The wide range of battery systems: From micro- to structural batteries from biodegradable to high performance batteries

The wide range of battery systems: From microto structural batteries, from biodegradable to high performance batteries Carlos M. Costa a,b,1,* , Manuel Salado c,d , Chiara Ferrara e , Riccardo Ruffo e , Piercarlo Mustarelli f , Rui Mao f , Sheng Feng f , Yuxiang Shang f , Xiaochen Wang f , Zhenkun Lei f , Ruixiang Bai f , Cheng Yan g , Kwon-Hyung Lee h , Sang-Woo Kim i , Tae-Hee Kim j , Sang-Young Lee k , Long Kong l , Qiang Zhang m , Harsha Devnani n,o , Shikha Gupta p , James F. Rohan q , Neil S. Curtis q , Abhishek Lahiri r , Yinghe He r , S. Lanceros-Mendez a,c,d,* a Physics Centre of Minho and Porto Universities (CF-UM-UP) and Laboratory of Physics for Materials and Emergent Technologies, LapMET, University of Minho, 4710-057 Braga, Portugal b Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, 4710-053 Braga, Portugal c BCMaterials, Basque Center for Materials, Applications and Nanostructures, UPV/EHU Science Park, 48940 Leioa, Spain d IKERBASQUE, Basque Foundation for Science, Bilbao 48009, Spain e Department of Materials Science, University of Milano-Bicocca, and GISEL-INSTM, Via Cozzi, 55, 20125 Milano, Italy f State Key Laboratory of Structural Analysis, Optimization and CAE Software for Industrial Equipment, Dalian University of Technology, Dalian 116024, China g School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD 4001, Australia h Ulsan Advanced Energy Technology R&D Center, Korea Institute of Energy Research (KIER), Ulsan 44776, Republic of Korea i Department of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea j School of Chemical Engineering, University of Ulsan, Ulsan 44610, Republic of Korea k Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03772, Republic of Korea l Institute of Flexible Electronics, Northwestern Polytechnical University, Xi’an 710129, China m Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China n Department of Sciences, School of Sciences, Manav Rachna University, Faridabad 121004, India o University Instrumentation Center, Manav Rachna University, Faridabad 121004, India p Department of Chemistry, Faculty of Engineering and Technology, Manav Rachna International Institute of Research & Studies, Faridabad 121004, India q Tyndall National Institute, Lee Maltings, University College Cork T12 R5CP Cork, Ireland r Department of Chemical Engineering, Brunel University of London, UB8 3PH Uxbridge, United Kingdom ARTICLE INFO Keywords: Different battery systems Smart capabilities Circular Economy Recycling issues ABSTRACT Battery systems are essential components of the on-going energy transition and digitalization of society. With the need to power an increasing variety of portable and stationary systems, ranging from disposable point-of-care devices or smart packaging systems to applications in portable computers and electric cars, an increasing variety of batteries and battery systems are being developed, each aiming to specific sets of required performance parameters, including energy and * Corresponding authors at: Physics Centre of Minho and Porto Universities (CF-UM-UP) and Laboratory of Physics for Materials and Emergent Technologies, LapMET, University of Minho, 4710-057 Braga, Portugal. E-mail addresses: [email protected] (C.M. Costa), [email protected] (S. Lanceros-Mendez). 1 All authors contributed equally to the review, by being in charge of different sections. Contents lists available at ScienceDirect Progress in Materials Science journal homepage: www.elsevier.com/locate/pmatsci https://doi.org/10.1016/j.pmatsci.2025.101506 Received 16 January 2024; Received in revised form 18 January 2025; Accepted 7 May 2025 Progress in Materials Science 154 (2025) 101506 Available online 14 May 2025 0079-6425/© 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ). power density, cycling stability, flexibility, degradability, environmental impact or improved integration into the specific application context. This work analyzed the state of the art of the different materials and geometries, performance parameters and applications of the different battery systems. We discuss the rationale behind each material selection, the processing technologies and the integration into the specific application, taking into account the whole life-cycle of the battery. Further, the main challenges posed for each battery type will provide a roadmap for their successful development and application. 1. Introduction: performance parameters and main characteristics of batteries systems Energy and environmental issues are the two most pressing global issues that society will face in the next half century, considering that fossil fuels are currently the main source of energy used to satisfy human needs and that the reduction of their is necessary, as they decisively contribute to climate change and global warming [1–3]. Given the need to reduce greenhouse gas emissions from fossil fuels and the increasing energy demand, related to population growth and improved socio-economical conditions, the focus is directed towards the development and implementation of technologies and devices related to renewable energies, i.e. sustainable energy generation and storage, also related to the electrification of the economy and society [4,5]. There are a variety of systems to generate energy in a sustainable way, including solar, wind, or hydroelectric, among others, in which energy efficiency is often also closely linked to energy storage and conservation [6,7]. After electricity is produced, it needs to be effectively stored for its use in various applications or during times of low demand [8] where energy storage devices are also required [9]. Research and technology related to energy storage systems is a rapidly evolving area based on the objective challenges posed by energy transition and the need to power an increasing number of very different portable electronic devices, as well as by the rapid implementation of the electric car, among the most relevant areas [10,11]. In this scope batteries are one of the most suitable systems for a wide range of applications, for which it is necessary to properly tailor capacity, energy and power density, and operational potential window, all dependent on the materials used for battery development [12]. Further, rate capacity, cycle life and coulomb efficiency of the batteries must be optimized, while properly addressing the detrimental aspects leading to leakage current and selfdischarge [13]. Furthermore, additional issues such as safety, economic viability, material recovery and recyclability are important in the field of batteries [14]. A separator with electrolyte, and two electrodes with different potentials (i.e., cell voltage), together with the collectors, make up a traditional battery [15]. The electrodes (anode and cathode) are composed of a range of materials with various functions (active material, polymer binder and conductive additive) that vary depending on the type of battery [16,17]. Thus, innovations in battery systems are being implemented at different levels, mainly driven by the novel materials applied to their different components to improve performance and safety, while reducing environmental footprint [18]. The most implemented and efficient energy storage devices for a variety of uses, including computers, smartphones, electric cars, and even home storage systems, are lithium ion batteries [19]. With the growth of the electric vehicle market, there is a strong dependence on this technology which will lead to an increasing demand for lithium and other materials needed to manufacture batteries, creating dependence on these resources and bringing scarcity problems similar to those observed nowadays with fossil fuels [20]. Furthermore, using liquid electrolytes in lithium-ion batteries still has certain drawbacks, primarily related to durability and safety concerns [21]. Solid-state batteries, which are based on solid polymeric electrolytes, are an efficient way to get around these limitations [22]. These battery types have been developed and are implemented in applications that require high energy value and efficiency, but recently, the field of batteries is experiencing a strong evolution to develop batteries matching the specific application and performance parameters requirements instead of implementing a single battery concept for all applications. Thus, printed batteries, microbatteries, organic batteries or batteries following the life-cycle of a specific application (from disposable point-of-care systems to smart packaging or agriculture 4.0) are being developed [23–25]. Similarly, structural batteries are a focus of important developments to take advantage of the energy provided by renewable sources [26]. The structure of this review is presented schematically in the Scheme 1. The review is basically divided in 4 sections: fundamentals of batteries, wide range of batteries, smart capabilities for different battery systems and circular economy and recycling issues. Thus, in contrast to any other review on the area, the present one focus on all types of batteries, analyzing their most relevant materials, geometries, performance parameters, and applications areas. Further, the main challenges to be addressed in the near future for each battery type are also addressed. This contribution does not pretend to be just a summary of the relevant state of the art, but to critically analyze it and provide a roadmap for future developments in order to positively contribute to the implementation of the wide range of battery types in the areas for which they are more appropriate, contributing to the energy transition in the most efficient and sustainable way. 2. Processing and fabrication technologies The rapid expansion of the lithium-ion battery (LIB) market, driven primarily by the electric vehicle (EV) sector, has boosted C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 2 substantial advances in battery processing and manufacturing. This growth encompasses the complete LIB production cycle, from raw material preparation to cell assembly (Fig. 1), effectively bridging the gap between academic research and industrial-scale applications in a variety of ways [27]. The EV battery industry is driven by a commitment to efficiency and sustainability, with yield optimization emerging as a key priority. In this context, yield—the proportion of high-quality products within the total production output—serves as a vital measure of manufacturing efficiency, cost-effectiveness, and environmental impact. Due to the inherent complexities of the manufacturing process, battery cell production lines often face yield rates around 40–60%. However, as production lines mature (e.g. Asian battery manufacturers) and incorporate advanced technologies, this yield can be improved (e.g. 99%) [28]. As a result of the manufacturing process optimization, a significant sharp reduction in LIB pack costs, which declined by approximately ~90% between 2011 and 2024, reaching around $88 per kilowatt-hour, has been achieved [29]. Nevertheless, sustaining this trend of cost reduction will require continuous improvements in both material innovation and manufacturing processes. Materials remain the most substantial contributor to LIB costs, and integrating new active materials introduces additional challenges for established manufacturing techniques. For instance, the inclusion of silicon in graphite anodes (that will increase by a factor of 10 the capacity of the cell: graphite: 372 mAh⋅g −1 vs silicon: 3579 mAh⋅g −1 ) demands extra processing steps, such as surface passivation of silicon [30]. Also, due to the high cost of cobalt, there has been increasing interest in developing nickel-rich cathodes. However, due to the oxidation state of nickel in the material (e.g. Ni +3 in high-nickel NMCs), it is also important to understand the reactions between cathode materials and water that occur within industrially relevant time scales and processes to prevent gas generation [31]. Developing advanced processing methods that can accommodate new materials is essential for further progress. In Scheme 1. Schematic diagram illustrating the various sections into which the review is organized. Fig. 1. A) typical process steps applied in a lib cell production plant. b) average prismatic cell manufacturing cost (data adapted from Bonsai Technology Srl) [48]. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 3 addition to materials innovation, the approaches, challenges, and constraints in key stages of electrode fabrication and cell assembly are crucial. The energy-intensive electrode drying process (Fig. 1a and b), in particular, is a focal point for optimization due to its influence on both manufacturing costs and the final performance of the battery. Techniques including optimizing the mixing sequence, increasing solid content in slurries, applying multiple drying zones, and adopting radiative drying methods offer significant potential for reducing energy demands in this step [27,29,32,33]. Emerging electrode processing materials and methods, such as NMP-free [34], aqueous [35], and dry processing [36,37], promise to further decrease manufacturing costs, reduce energy use, and cut greenhouse gas emissions. For instance, while NMP-free electrode fabrication entails key advantages such as improved electrode quality (e.g. stronger adhesion and cohesion of the electrode components) as well as the potential for new applications (e.g. all-solid-state batteries (ASSBs) and pre-lithiation in LIBs), several challenges need to be addressed before widespread commercialization. Among them, 1) the tendency of different electrode materials to agglomerate during dry mixing makes it challenging to achieve a uniform distribution and good interfacial interactions between the active material, binder, and conductive additives. 2) Maintaining a consistent mass loading of electrodes is critical for ensuring reliable LIB performance. The dry mixture used in the solvent-free processing presents a lower fluidity than the slurry in the SC process, making it more challenging to achieve the same level of mass loading consistency and 3) Different binders are required for the various dry electrode fabrication techniques (e.g., PVDF for dry spraying, thermoplastics for 3D printing and melting extrusion) [38,39]. The stability and flexibility of these binders, especially for use with different active materials, need to be further investigated. Enhancing energy density through minimizing inactive components, developing self-supporting electrodes, and increasing electrode areal loading is also crucial. However, producing high-loading, thick electrodes introduces mechanical challenges related to their integrity and adhesion [40]. To address these technical hurdles, new electrode architectures are being developed, including gradient-structured electrodes [41] and vertically aligned pore designs [42]. Techniques such as laser processing [43], freeze casting [44], and co-extrusion [45] facilitate these innovative architectures, though the scalability, throughput, and cost-efficiency of these methods are yet to be fully proven. One of the most promising approaches is laser structuring of composite electrodes [46], as part of the 3D battery concept [43,47]. This can improve battery performance and safety, as well as production reliability. The key advantage is that laser-generated artificial porosity enables more homogeneous and rapid wetting of the electrode with the liquid electrolyte. As a result, inhomogeneous wetting with dry electrode areas are avoided which can initiate electrochemical degradation and cell failure. This offers a significant reduction in production costs, increased battery lifetime, and easier translation into high-energy and high-power thick-film batteries. Given the high standards for cycle life, calendar life, and defect tolerance—particularly in large-scale applications like EVs—LIB manufacturing increasingly relies on continuous processes, automation, and stringent quality control systems. Establishing the connection between defects and cell performance is critical for creating effective criteria for scrap and quality determination. Bearing this in mind, it has been proposed the use of a digital twin that consists on a dynamic, virtual replica that mirrors a physical product, process, or system in real time [49]. This sophisticated model serves as both a window into current operations and a laboratory for future possibilities (e.g. beyond lithium technologies). Engineers and operators can use it to predict performance, optimize maintenance schedules, and test scenarios without risking the actual asset. The true benefit of digital twins lies in their bi-directional connection with physical assets. As conditions change in the real world, sensors relay this information to update the digital model automatically. This continuous feedback loop enables predictive Fig. 2. Recycling processes in order to promote a circular economy. Adapted from Ref. [50] with permission from Wiley, Copyright 2022. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 4 maintenance, performance optimization, and data-driven decision making. As the first generation of EV batteries reaches the end of its operational life, LIB recycling has become increasingly important [48]. By 2040, projections indicate that electric vehicles will comprise about two-thirds of all cars. However, current LIB designs rarely account for recyclability, complicating the recovery of battery-grade materials. Europe is addressing this challenge by implementing new policies to foster battery circularity and improve the recovery of critical materials like lithium, cobalt, and nickel. These policies aim to mitigate environmental impact and reduce dependency on imported resources. Currently, however, European recycling rates remain low, with only 8–22% of materials successfully recovered [28]. As schematically illustrated in Fig. 2, when a LIB reaches its end of life, several pathways are possible. It can be disposed of in a landfill (an undesirable scenario), repurposed for a second-life application in a less demanding setting −typically stationary energy storage −or recycled to close the loops for both materials and energy [50]. While LIBs will continue to dominate the EV market, new battery technologies, including lithium-sulfur and solid-state batteries, are on the horizon. Developing specialized manufacturing processes for these next-generation battery systems will be essential to realize their potential and overcome unique challenges, such as stability, compatibility, conductivity, and interface issues between the cathode and solid-state electrolyte. 3. Conventional lithium-ion batteries The most widely used energy storage system is lithium-ion batteries (LIBs), which are expected to expand at a compound annual growth rate of 14.2% between 2023 and 2032 [51] due to the expansion of the electric vehicle market and applications in electronic devices like computers and smartphones [52]. Relaying on the discoveries achieved by M. Stanley Whittingham, John B. Goodenough, and Akira Yoshino— Nobel Prize in Chemistry in 2019—Sony commercialized the first battery prototype in 1991 [53]. In comparison to other battery systems like NiMH (nickel-metal hydride) and Ni-Cd (nickel–cadmium), lithium-ion batteries are characterized by improved characteristics including lightweight, higher power and energy density value, more charge/discharge cycles, and no memory effect, among others [52]. Fig. 3 shows the evolution of the different generations of these batteries in terms of materials, with the current generation 3 being based on different materials for both anodes and cathodes. Despite the success, more work is required to enhance the characteristics and features of its various components, including the electrodes and separator/electrolyte. The cathode, or positive electrode, establishes the battery’s capacity, while the anode, or negative electrode, needs to sow a low potential in order to deliver a high voltage to the cell [54]. Whatever the electrode type, it is formed by an active material, conductive additive, and binder polymer [55]. The conductive additive improves the electrode’s electrical characteristics, the polymer binder connects the other components (active material and conductive additive) and increases the electrode’s mechanical stability, whereas the active material is responsible for the intercalation and deintercalation process [55]. Because of its long life cycle, abundance, electrochemical stability, ease of production, and affordability, graphite is the most commonly used active material for anodes [56]. With respect to active materials for the cathode, it is selected depending on the specific application requirements. Lithium cobalt oxide (LiCoO 2 ) was the first active material used due to its good capacity retention, high structural reversibility (below 4.2 V vs Li + /Li) and good rate capability [57]. Among the different active materials, the ones that stand out are lithium iron phosphate (LiFePO 4 , LFP) and lithium-nickel–cobalt-manganese oxide (LiNiCoMnO 2 , NMC), often used in electric vehicles due to their as low-cost and nonFig. 3. Roadmap of the different generations of lithium batteries. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 5 toxicity, no memory effect, good thermal stability, and environmental friendliness, among others [58]. NMC active material exhibits higher capacity and tap density compared to other active materials, with both Ni and Co participate in surface redox, whereas Mn is non-redox active [59]. By preventing contact between the two electrodes, the separator—which takes the shape of a porous or gelatinous electrolyte—improves the battery’s mechanical flexibility and resilience while supplying the required ionic conductivity without electronic conductivity [60]. Currently, these battery systems are the most studied, developed, produced and integrated in devices. Every year, an increasing number of works are published that address fundamental concerns related to energy, power, safety, sustainability, processability and reliability in order to improve their performance [21,61]. Additionally, attempts are being made to develop new capabilities for the batteries, like self-sensing, self-healing, and thermal shutdown [62–64]. The development of solid electrolytes for solid-state batteries represents another strategy for improved durability and safety [65]. 4. Beyond lithium-ion batteries As discussed in Section 2, recycling spent lithium-ion batteries (LIBs) is essential for addressing environmental and resource-related challenges. Another possibility to address those issues is by developing alternatives to current main stream technology, the mains ones −sodium-ion, solid-state electrolyte, and lithium-sulfur (Li-S) batteries −offering potential advantages in safety, environmental impact, or energy capacity [66]. Sodium-ion batteries represent a promising alternative to traditional lithium-ion technology, offering a complex mix of benefits and limitations tailored to specific applications. One significant advantage is the abundant availability of sodium −approximately 1,000 times more prevalent than lithium −and its significantly lower water requirements for extraction, reducing production costs by 30–50% compared to lithium-ion [67,68]. Additionally, sodium batteries can be manufactured in existing facilities and safely transported due to their ability to discharge fully to zero volts. However, they currently fall short in energy density, with a range of 140–160 Wh kg −1 compared to lithium’s 150–220 Wh kg −1 , and they support fewer charging cycles. This lower density makes sodiumion batteries less suitable for applications where space and weight are critical, such as portable electronics or high-performance EVs [69]. Furthermore, limited commercial availability and fewer manufacturers restrict their current application potential. Nonetheless, sodium-ion batteries show promise in stationary energy storage, grid-scale implementations, and budget-focused EVs where cost benefits could outweigh density limitations. Solid-state batteries, which use solid electrolytes instead of liquid ones, offer several advantages, including a reduced risk of dendrite formation, higher energy density (potentially 2–3 times greater than lithium-ion batteries, enabling longer EV ranges), and faster charging [70]. They also perform well in extreme temperatures and show promising cycle longevity, with some prototypes enduring thousands more charge–discharge cycles than traditional batteries. Various solid-state electrolyte (SSE) materials are under study, such as polymeric, oxidic, and sulfidic types, each with unique ionic conducting and mechanical characteristics [71]. Emerging materials like metal–organic frameworks (MOFs) offer tunable functionality and structured ion channels [72], while chloride-based SSEs exhibit high ionic conductivity and compatibility with oxide cathodes [73]. However, high production costs and scaling challenges currently limit solid-state battery applications to smaller devices like wearables and IoT products. Technical issues related to the solid-electrolyte interface, dendrite prevention, and mechanical stress during charge–discharge cycles also impact their longevity. Despite these challenges, major companies continue to invest in solid-state technology, viewing it as a potential future standard for energy storage. This battery type is explained in more detail in the next section. Aqueous Zn-ion batteries (ZIBs) operating within a pH range of approximately 4 to 5.5, offer a compelling alternative to lithium-ion batteries for stationary grid energy storage. Their key advantages include high safety, environmental friendliness, non-toxicity, high specific power, excellent reversibility, and affordability due to the abundance and low cost of zinc [74]. These characteristics make ZIBs a viable, green, and cost-effective technology for large-scale applications. However, achieving widespread adoption requires overcoming specific challenges, such as enhancing energy density and addressing parasitic hydrogen evolution during zinc electrodeposition. In order to overcome these challenges, focused research on enhancing energy density (e.g cathode materials should be designed to deliver an average discharge voltage of at least 1.0–1.2 V) [75], optimizing electrolyte formulations (including the use of additives [76], e.g propylene glycol, 1,2-butanediol or pentanediol), and adhering to standardized testing [77], such as conducting long-term cycling tests at around 1C or testing under “electrolyte-starving” conditions to better simulate real-world scenarios rather than flooded conditions, will accelerate their readiness for deployment in power grid applications. Lithium-sulfur batteries combine lithium anodes with sulfur cathodes, offering an alternative that maintains lithium’s benefits while replacing critical materials with more abundant sulfur. These batteries have a theoretical energy density up to nine times higher than lithium-ion batteries but currently face issues with limited chargeability and cycle life. Research efforts focus on enhancing performance through several strategies: (a) modifying electrolyte solvation properties to improve voltage profiles, polysulfide solubility, and cyclability [78], (b) using sulfurized polyacrylonitrile (S@PAN) as a cathode material to reduce polysulfide dissolution and enhance cell stability [79], (c) incorporating kinetic promoters to accelerate sulfur cathode reactions (e.g., heterogeneous, homogeneous, and semi-immobilized promoters) [80], and (d) utilizing redox mediators (both solid and soluble) to catalyze sulfur redox reactions, which has shown promise in improving Li-S cell performance [81]. These advancements aim to address key limitations in LiS battery technology, making them increasingly viable for practical applications. Several other promising but commercially immature technologies, including lithium-air (Li-air), zinc-air (Zn-air) batteries, and multivalent systems like calcium (Ca 2+ ), magnesium (Mg 2+ ), and aluminium (Al 3+ ) batteries, are under active development. Recent C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 6 advancements have focused on improving catalysts, electrolytes, and electrode materials to enhance the performance, stability, and scalability of these alternatives (Table 1): •Li-Air Batteries: Research into NiO/ZrO 2 [82] and lattice-activated SnTe [83] catalysts has shown promise for improving LiOH decomposition and oxygen diffusion, as well as reducing exposure to CO 2 and H 2 O. Polymer electrolyte innovations also enhance stability and cycling under ambient conditions, addressing critical issues in cathode and electrolyte efficiency [84]. •Zn-Air batteries: Limited energy density remains a significant challenge for Zn-air batteries as practical applications have been struggled to achieve the potential high theoretical energy density. Research focused on pore size engineering of the electrode materials allows to increase the density of active sites, including core–shell design, space confinement, and hierarchical structures [85]. Additionally, electrolyte additives, such as zinc acetate and citric acid, or solid-state electrolytes such as polyacrylamide polymer with a highly amorphous dual-cation ionomer [86] can enhance the performance of Zn-air batteries by improving the shape change of the zinc electrode. •Calcium Batteries: Notable developments include a rechargeable Ca/Cl 2 system and enhanced cathode materials, such as carbonconfined sulphur and BaV 6 O 16 ⋅3H 2 O composites, offering high specific capacities and extended lifespans [87]. A solvation strategy using low-donor number (DN) propylene carbonate has also improved rate performance in vanadium-based systems [88]. •Magnesium Batteries: Efforts to stabilize FeS 2 cathodes aim to reduce shuttle effects and improve cycling stability, though challenges remain with dendrite formation and electrolyte flammability [89]. Ongoing work focuses on enhancing safety and scalability for large-scale applications. •Aluminium Batteries: Advances in chloroaluminate-based solid polymer electrolytes have achieved higher electrochemical stability and ionic conductivity, which are important for aluminium-graphite cells’ performance [90]. Rather than relying on a single replacement for lithium-ion batteries, a diversified approach tailored to specific applications is likely to be more sustainable. By developing multiple “fit-to-purpose” battery technologies, this approach could help mitigate the environmental and social impacts of lithium mining—such as high water usage, CO 2 emissions, and disruptions to Indigenous communities—while meeting the growing global demand for energy storage. 5. Solid-state lithium-ion batteries 5.1. Introduction Lithium-ion batteries (LIBs) have become ubiquitous electrochemical energy storage systems for portable electronics and electric vehicles [28,91]. The expansion of their market and fields of applications have been driven by their remarkable energy density, long cycle life, and low cost [92]. However, conventional LIBs on the market today rely on the use of liquid electrolytes composed of highly flammable organic solvents, which pose inherent safety risks. Today, commercial LIBs contain lithium hexafluorophosphate (LiPF 6 ), lithium bistrifluoromethanesulfonimide (LiTFSI), lithium bismethanesulfonimide (LiFSI), lithiumbis oxalateborate (LiBOB) dissolved in carbonate-type such as dimethylene carbonate (DMC), diethylene carbonate (DEC), ethyl methyl carbonate (EMC) and cyclic carbonates (like ethylene carbonate (EC) and propylene carbonate (PC)), sulfone-type (dimethyl sulfite, DMS) or sulfolane-based solvents. This liquid electrolyte is supported by a mechanical separator in polypropylene (PP) or/and polyethylene (PE), with addition of glass fiber providing the physical separation of the electrode [93,94]. The risks associated with this type of electrolyte include leakage, short-circuiting, and consequently the possibility of fires or explosions. Furthermore, the limited electrochemical window of liquid electrolytes hinders the use of high-capacity and high-voltage electrode materials, thus restricting the battery performance Table 1 Some representative battery technologies under research and development for next generation energy storage. Technology Advantages Drawbacks Li-air batteries •high theoretical energy density (10 times greater than that of lithium-ion) •specific energy (3000 Wh⋅kg −1 vs 250 Wh⋅kg −1 of Li-ion). •complex chemistries involved in the charge/discharge cycles •poor reversibility and cyclability •electrolyte instability •lithium metal anode instability Zinc-air batteries •theoretical energy density (3 times greater than that of lithium-ion) •minimal fire risk and non-toxic components •abundance of zinc, entails a lower cost compared to lithium •short cycle life due to zinc dendrite formation •sluggish oxygen reduction reactions Calcium batteries •abundant element in Earth’s crust •lower cost compared to lithium •higher energy density than lithium-ion batteries due to the transfer of multiple electrons •suitable cathode materials that can accommodate the larger size of calcium ions •dendrite formation and electrode deterioration Magnesium batteries •slow diffusion of magnesium ions in conventional electrolytes and cathode materials •cathode materials that can accommodate the insertion of Mg 2+ Aluminium batteries •parasitic hydrogen evolution reaction during charging, which reduces efficiency and can cause corrosion issues •cathode materials that can accommodate the insertion of Al 3+ C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 7 Fig. 4. Proposed classification for the solid-state electrolytes, identifying the categories and correlating them with some relevant physical and transport properties. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 8 [93–95]. All Solid-State Batteries (ASSBs) have emerged as a promising strategy to produce next-generation energy storage technology, aiming to address these limitations [96–98]. The definition of ASSBs thus is specifically referred to the nature of the electrolyte. The switch to ASSBs allows not only to overcome the main limitations of traditional liquid-electrolytes based batteries, but also to meet the required standards for the next generation batteries, particularly in the field of electric mobility. Today, commercial LIBs are approaching their performance limit in terms of energy density, assessed around 300 Wh kg −1 . ASSBs indeed represent the picklock to access the lithium-metal battery design (LMBs), exploiting the advantages of metal lithium (3860 mAh.g −1 capacity, −3.04 V vs SHE potential) and allowing for super high energy density batteries. Indeed, the removal of the inert separator and the reduced electrolyte thickness can lead to energy density in the range of 500 Wh.kg −1 [96]. At the same time, this poses extra challenges as the use of metal lithium involved the formation of dendrites, large volume changes, interfacial reaction and new phases formation, and overall safety issues. Moreover, the traditional cathode materials and lithium metal anode (LMA) present inherently different challenges and problems, difficult to address with the same approach and thus making the development of suitable electrolyte systems even more demanding. ASSBs are distinguished by replacing the flammable liquid electrolyte and separator with a non-flammable and mechanically robust solid-state electrolyte (SSE). This fundamental shift offers mainly enhanced safety and improved cycle life stability [99,100]. Indeed, the ideal SSE should possess the following desirable characteristics: •High ionic conductivity in a wide temperature range, enabling for improved battery’s rate performance under different conditions (ideally σ ≥10 -3 S cm −1 at RT, with practically null electronic contribution, i.e. below 10 -10 S cm −1 ). High Li transference number, t Li + > 0.5, ideally ~ 1. This transference number is defined as the ratio between the current transported by cations and the overall current in the cell [101]. •Wide electrochemical stability window, ESW, up to 6 V vs Li + /Li, opening the route for the exploitation of high-voltage cathode, nickel-rich and cobalt-free cathodes, boosting the overall energy density of the battery. At present, liquid organic electrolytes have ESW ~ 4–4.5 V [102]. •Good chemical stability with traditional electrodes and new possible electrodes (metal anode), which is crucial for long cycle life and overall performance [102]. •Low interfacial resistance with the electrodes; minimizing the resistance at the interface between the SSE and the electrodes is vital for efficient battery charging and discharging [102]. •High safety, low flammability. Ideally, this should allow reaching EUCAR =1–2 for the overall battery in automotive applications [97,103]. •High mechanical strength (Young modulus >5.5 GPa to hinder dendrites formation). Resistance to dendrites’ formation, so opening the way to the use of LMA with 3870 mAh.g −1 capacity, density 0.59 g.cm −1 , the lowest possible potential −3.4 vs SHE, and improving the energy density [104]. 5.2. Materials, strategies, and applications Several approaches and classes of SSEs have been explored. In the early stage of this research’s field, three main categories could be identified: polymer electrolytes, ceramic inorganic electrolytes, and composite electrolytes. These classes will be discussed in detail in the following sections [100,104–108]. Considering the “end members”, i.e., the pure ceramic and pure polymer electrolytes, they have been considered and widely investigated, nevertheless their inherent weaknesses (such as poor ionic conductivity at room temperature for ceramic systems and mechanical properties not sufficient to block dendrite growth for the polymeric systems among the others), have led to the investigation of composite as main strategy to mitigate the drawbacks of these individual components. Today, the use of composites has overcome the other strategies, thus we here propose and discuss the specific classification of composite electrolytes, as following: −Ceramic-in-Polymer, CIP [106,109,110]. −Polymer-in-Ceramic, PIC [104,111]. −Quasi-Solid Electrolyte, QSE [112–114]. To properly discuss this classification, the end members (polymeric systems and ceramic materials) are here discussed to highlight both pros and cons of the single components and thus better understand the synergistic effect of the preparation of a composite, as reported in Fig. 4. 5.2.1. Ceramic materials Inorganic solid electrolytes (ISEs) can be further categorized into three main types based on the chemical composition, i.e. oxides, sulfides, and halides [115,116]. All these classes of materials share some common features. Generally, these systems are composed by a rigid (order or disordered) inorganic framework accommodating Li ions on sites ideally connected through planes or channels. The transport properties of Li ions within the structure are supported by the presence of point defects (such as vacancies, interstitial species, anti-site defects) allowing for the Li ion diffusion, generally controlled by proper doping and substitutions, and follow the activated diffusion described by the Arrhenius equation. This provides Li transference numbers close to 1; nevertheless, ISEs present lower ionic conductivity respect to the liquid systems (in the range of 10 -6 – 10 -3 S cm −1 at RT) but at the same time good electrochemical and thermal stability, while the chemical and mechanical properties should be discussed case by case [115,116]. Generally, they are also characterized by poor interfacial compatibility, high interfacial resistance, poor flexibility, high cost of production and scalability. Indeed, some of the C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 9 considered: the polymeric matrix, the ion-conducting filler, and the polymer-ceramic interface [106,111,168,169]. Critical aspects within CIPs are related to particles’ dimensions and filler-to-polymer ratio. If the filler is passive, a major role is played by the particles’ dimensions and, consequently, by the overall surface area. For particles in the micrometer range, which means surface area of the order of few m 2 /g, filler addition only determines an improvement of mechanical properties, whereas the conductivity decreases by dilution of the active phase. If the particles are in the nanometer range (i.e. specific areas of hundreds m 2 /g) there is an initial increase of the ionic conductivity, even by one order of magnitude or more due to space-charge effects [175]. The conductivity maximum is in the range 5-15 wt% of filler, followed by decrease for dilution. If the filler is active, the particles’ dimension plays a minor role, and it is possible to increase the filler phase content up to several tens wt.%. This leads to the possibility to fabricate PICs (see below). The introduction of an inorganic insoluble filler complicates the preparation of the electrolyte, that strongly affect the final performance of the final device. Indeed, the homogeneous dispersion of the filler, avoiding clustering or precipitation need to be controlled. Preparation methods include dry methods (dry mixing of components followed by cold or hot pressing), wet chemical methods (dispersion of components in a solvent of the polymer and non-solvent for the filler, casting, and evaporation of the solvent), high viscosity methods (formation of a paste without the use of a solvent, formation of the membrane with desired thickness) [176,177]. Fig. 10. (a) Scheme of mechanism of Li transport in the PIC system with LLZT and in situ polymerization. Reproduced from Ref. [98] with permission from Springer, Copyright 2024; (b) example of PIC based on garnet. Reproduced from Refs. [178,186] with permission from Springer and Elsevier, Copyright 2023, 2024. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 16 5.2.2.5. Polymer-in-ceramic. The polymer-in-ceramic (PIC) approach was initially developed to overcome the main limitation of ceramic electrolytes, essentially the poor mechanical properties, poor interface contact and grain boundaries resistance. In principle, the polymer is added in small or at least minority fraction (<50 % by weight) and can be an inert component (i.e. non-participating in the ionic conductivity) or an active one if present ionic conductivity [179]. The fine calibration of the weight ratio among the components is crucial for the enhancement of the mechanical and transport properties. Moreover, if the polymer fraction is inert, the existence of percolation thresholds should be considered. According to standard General Effective Medium theories, thresholds of inert around 33 wt% should be considered [180]. The morphology and particle size of the inorganic fraction should be carefully controlled. The electrolyte disks are obtained by mixing the polymer and inorganic components and subsequent hot pressing of pellet preparation by heating. However, free-standing membranes with high content of ceramic are not easy to achieve; thickness is relevant but contributes to determining the energy density of the cell. Other typical preparation procedures include dry methods (dry mixing and casting and tape casting, in situ polymerization, infiltration method with the use of solvents [181,182]. The contact with the electrode is also extremely relevant and different from the case of liquid electrolytes (LEs). Indeed, LE can penetrate the pores of the electrodes and wet the electrodes, forming a deep ionic connection, while with SE the ion transport is limited to the surface region as SE cannot penetrate the electrode. In addition, the electrodes can undergo volume variation during charge and discharge, and SE can undergo cracking due to the induced stress. These problems can be partially overcome with the use of a polymer fraction (active or inactive), used also as a binder in the electrode formulation. This not only provides intimate contact between the electrode and electrolyte components, with continuous ionic paths for ion diffusion, but also enhances the compatibility of the components. The use of active polymer eliminates the need of inactive binder in the cathode preparation, providing an additional beneficial effect. Several examples of PIC electrolytes have been recently reported by our group, including poly(ethylene oxide)/Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (PEO/LATP) [183], PEO-grafted TiO 2 nanocrystals [184] (Fig. 10). The PIC concept has been also linked to the CIP one to obtain Janus membranes to separately optimize the interfaces towards anode and cathode. Jiang et al reported a bilayer ultrathin (~11 μ m) composite solid electrolyte membrane by exploiting a spontaneous precipitation of Li 7 La 3 Zr 2 O 12 in a polymer-lithium salt matrix. The PIC layer is toward a high-voltage cathode, which can effectively inhibit oxidative decomposition of electrolytes. The CIP layer is toward the anode can provide good flexibility. Experimental results show that the CSE bilayer membrane has not only high ionic conductivity but also satisfactory Li + transference number [185]. 5.2.2.6. Quasi solid electrolytes. The interfacial issues between the SSE and the electrodes, both with the anode (SEI) and the cathode (CEI), may strongly limit the cyclability and the long-time performance of the cell. In the last few years, there has been growing evidence that some residual fraction of solvents or non-solvents from membrane fabrication can strongly influence the functional properties of the electrolyte. This was reported chiefly for PVDF-based systems due to excellent mechanical and chemical properties of the fluorinated backbone. PVDF–LiClO 4 solid electrolyte membranes were prepared via solution-casting method employing a N,Ndimethylformamide (DMF)-tetrahydrofuran (THF) binary solvent. The electrolytes showed conductivity values as high as 2.03 × Fig. 11. (a) Ionic conductivity of PVDF-based QSE vs. residual DMF content. Reproduced from Ref. [188] with permission from Wiley, Copyright 2020; (b) cycling capability of QSE with different lithium salts. Reproduced from Ref. [187] with permission from Wiley, Copyright 2019; (c) thermogravimetric curves of samples with different aging. Reproduced from Ref. [189] with permission from American Chemical Society, Copyright 2024; (d) DFT modeling of the interactions among the different components in PVDF-based QSE. Reproduced from Ref. [189]. with permission from American Chemical Society, Copyright 2024. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 17 10 −4 S cm −1 at 25 ◦C and excellent cyclability in lithium metal cells (Fig. 11) [187]. The exact nature (true solid or semisolid) of these electrolytes was strongly questioned in the literature, chiefly as far as the exact nature of the ion transport mechanism is concerned. In fact, residual (or better permanent) DMF amount in the range 10–20 wt% were observed in the membrane, which could give origin to liquid-assisted transport [187,188]. In a recent paper, we studied the Li + transport mechanism in a model system consisting of PFDFHFP, lithium bis(fluorosulfonyl)imide (LiFSI) salt and DMF as permanent residue, combining a large set of experimental techniques (thermal analysis, NMR, IR and Raman spectroscopy, impedance spectroscopy) and Density Functional Theory (DFT) modeling. We showed that Li + -DMF interactions are predominant in these quasi solid electrolytes (QSEs) and are the basis of the effective ion transport mechanism. Permanent solvent amounts of the order of [DMF]/[Li + ] ~ 2–3 are needed to make QSEs able to practically work in a real environment [189]. Further improvements of QSEs properties could be obtained by preparing nanocomposite membranes. Silica-based hybrid nanofillers were obtained by grafting chains of poly(ethylene glycol) methyl ether (PEG) with different molecular weight on the surface of silica nanoparticles. The functionalized nanofiller improved the mechanical, transport and electrochemical properties of the QSEs, which showed good ionic conductivity values and high resistance against dendrite penetration, ensuring boosted long and safe device operation. The most promising result was obtained by dispersing 5 wt% of SiO 2 functionalized with short PEG chains (Mw =750 g mol −1 ). This system displayed ionic conductivity of 0.1 mS cm −1 at 25 ◦C, more than 250 h resistance to stripping/plating, and impressive results during cycling tests in LMB with LiFePO 4 cathode [190]. Other QSEs were recently reported in the literature to allow efficient strategies towards the improvement of functional properties, including: i) maximum attainable power density, ii) chemical and electrochemical stability, and iii) safety. These systems included patterned microporous and mesoporous membranes, metal–organic-framework based systems, and “soggy sand” electrolytes. Full details on these solutions could be found in this work [104]. 5.3. Emerging Horizons and outlook Despite the promising advantages of ASSBs, some major challenges need to be faced to reach the widespread commercialization of such devices. Overcoming these issues is crucial to unlocking the full potential of ASSBs. The key aspects to be addressed can be outlined in the following. •Enhancing ionic conductivity at room temperature. Efforts are underway to develop new SSE materials with higher ionic conductivity, especially at room temperature. This includes exploring novel electrolyte compositions, designing innovative electrolyte structures, and engineering ionic conduction pathways and mechanisms within SSEs. Considering the single components, several strategies can be developed. The ionic conductivity in the polymeric fraction can be improved by: i) suppressing the crystallization, ii) lowering the Tg, iii) modifying the intraand inter-chain path and coordination sites for Li ions. Functionalization, branching, copolymerization, polymer blending should be considered [159,191,192]. As the Li + transport number in the polymeric matrix is known to be low, work can be done in restricting or blocking the mobility of the anion. The anion groups could be immobilized within the polymeric chains by functionalization through covalent bond formation [193,194]. Due to the relevance of the polymer-ceramic interface as a possible fast ion pathway, the surface engineering of the filler can open new possibilities. Particle size, surface orientation, morphology could be tuned to modify the interface properties of the final systems [195]. •Improving interfacial stability. The electrode–electrolyte interface plays a crucial role in determining the performance of the whole battery, both in terms of power density and cyclability [195–197]. The SSEs are characterized by low contact area, resulting in limited transport properties at the interface; moreover, the resistance as the interphase generally increases with cycling due to electrode volume variations and SEI/CEI formation. Interfacial engineering strategies should be thus considered, including the introduction of buffer layers, modifying electrolyte compositions, and optimizing fabrication processes to stabilize these interfaces and reduce interfacial resistance. Introduction of bilayer systems (so called Janus membrane type), multilayer electrolyte (symmetrical and asymmetrical) could represent a strategy to properly face the specific cathode and anode interface problems [198,199]. Considering the cathode side, it must be considered that the problem of poor interfacial contact is here even more relevant as the cathode materials present a complex and inhomogeneous surface. The main strategy is represented by the preparation of composite catholyte, mixing the traditional cathode materials with the SCE. This can represent a further benefit for the aspect of energy density as the inactive binder can be substituted with the ionically conductive SCE [200,201]. •Suppressing dendrite growth. Preventing lithium dendrite formation and propagation is essential for ensuring the safety and longevity of ASSBs and the main challenge related to the use of LMA. Research in this area focuses on understanding dendrite growth mechanisms, developing SSEs with high mechanical strength, and exploring innovative cell design strategies to mitigate dendrite growth. Dendrite formation is not completely suppressed by SSE due to a combination of contributions such as the low Li metal C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 18 hardness, the surface and bulk defect in the SE, imperfect and poor interfacial contact. Actually, the first step is the deep and complete comprehension of the dendrite growth mechanism and the parameters affecting their growth, the electrode and SE degradation. The main strategy is suppressing the dendrite growth using high shear modulus SCEs, the minimum values required is 6.8 GPa. To this the implementation of rigid ceramic filler has been proposed [170,174,202,203]. •Large scale production and cost-effectiveness. Scaling up ASSB fabrication processes at competitive costs is essential for their commercial adoption. Efforts are underway to develop scalable and cost-effective manufacturing methods for SSE materials and cell assembly, paving the way for mass production of ASSBs [152,204]. •Design-for-recycling. This sector is becoming progressively more important considering the expected exponential growth of the automotive market. This growth, soon, will increasingly concern the ASSB sector. It will be necessary to design cells that can be disassembled with simple mechanical methods, reducing as much as possible the processes of formation of extensive interphases during the life of the battery. Furthermore, the materials will have to be reprocessable in a safe way and with low environmental impact. Being able to use processes in an aqueous environment will be of fundamental importance [205]. The most recent research is pointing out that CIP approach can lead to flexible and down-sizable devices, thanks to their high flexibility, low cost of components and scalable production. In contrast, the PIC approach is more appealing for EVs applications due to the high energy density, high mechanical properties and globally increased safety. Wide development possibilities are connected to the realization of quasi-solid systems with the introduction of optimal quantities of ionic liquids, solvents or non-solvents, etc. Also, the fabrication of Janus-type systems, optimized separately for the two anodic and cathodic interfaces, will allow to improve the long-term performance, the safety and the possibility of direct recycling-recovery of the components. In conclusion, solid-state batteries represent an exciting path toward safer, more energy-dense, and longer-lasting energy storage systems. Solid-state electrolytes are key to realizing the transformative potential of ASSBs. Addressing the remaining challenges through continuous research and development efforts will pave the way for the widespread adoption of ASSBs, revolutionizing the energy storage landscape across various sectors. 6. Structural batteries 6.1. Introduction The transportation industry is the largest contributor to greenhouse gas emissions, responsible for approximately 29 % of global emissions [206]. To protect the environment and expedite the transition towards green, low-carbon energy, industries such as new energy vehicles and aerospace are being heavily promoted. One of the primary challenges faced by batteries today is their capacity. Both electric vehicles (EVs) and aircraft require multiple battery packs for extended range; however, this leads to increased weight, larger battery volumes, and reduced energy density [207,208]. Although significant efforts are underway to develop high-energy–density electrode materials, such as lithium-sulphur batteries [209,210] and metal-air batteries [211–213], these technologies remain some way from widespread commercialization and application [214]. As a result, an alternative research direction involves enhancing the functionality of batteries. In addition to providing energy storage, batteries can also serve as structural components, which are expected to meet the stringent demands for lightweight structures, reliability, spatial integration, and high energy density in sectors such as automotive and aerospace. Common structural materials, such as fibre-reinforced polymers, can reduce structural weight by 50 % to 70 % [215]. Among the various reinforced composite materials, carbon fibre (CF) is frequently utilized in the production of lightweight structural components due to its high specific strength and stiffness. Moreover, CF exhibits excellent electrical conductivity [216], presenting innovative possibilities for the development of lightweight batteries. The U.S. Army Research Laboratory (ARL) was the first to propose the combination of CF with battery materials, including CF as the anode, LiFePO 4 (LFP) and LiCoO 2 -coated metal substrates as the cathode, Fig. 12. A) uncoupled structural battery. reproduced from ref. [222] with permission from Elsevier, Copyright 2020, and b) coupled structural battery. Reproduced from Ref. [223] with permission from Elsevier, Copyright 2021. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 19 glass fibre as the separator, and integrating electrolyte into resin to preserve ion transport capability while providing structural support [217,218]. Subsequently, the potential of this structure for use in composite fuel cells and composite capacitors was also investigated [219]. Johannison et al. [220] estimated that employing a composite structural battery (CSB) with a similar design could reduce mass by 22 % when replacing traditional steel car roofs, by 4 % when replacing interior panels in aircraft, by 12 % when replacing electric ferry hulls, and by 20 % when replacing laptop chassis. Consequently, CSBs offer significant potential across multiple sectors, including electric vehicles, aircraft, spacecraft, marine vessels, sports equipment, and robotics. Current methods for CSBs can be classified into two categories [221]: Uncoupled structural battery: The battery and the structure remain as two distinct components. Specifically, a battery system is integrated into the composite structure, with the battery positioned within the interlayer of the composite material, as illustrated in Fig. 12a) [17–19]. Coupled structural battery: In this method, the energy storage material is combined with the structural material, often by coating or depositing the active material onto CFs. These CFs can serve as current collectors or active materials. Furthermore, both traditional liquid electrolytes and solid-state electrolytes (SSE) can function as the electrolyte, allowing materials such as anodes, cathodes, and electrolytes to demonstrate both structural and energy storage properties. In this case, the structure itself effectively becomes a “large battery,” as shown in Fig. 12b) [19–21]. To broaden the application of structural batteries, these batteries also exhibit significant plasticity and high flexibility. Depending on varying operational conditions, different structural forms, such as tubular [224] and wavy designs [225], have been developed. Additionally, advanced manufacturing techniques like co-extrusion deposition and 3D printing technology [226–228] are employed to create these innovative designs as shown in Fig. 13. Fig. 13. A) tubular csb. reproduced from ref. [224] with permission from Elsevier, Copyright 2021, b) wavy CSB. Reproduced from Ref. [225] with permission from Elsevier, Copyright 2023, c) and d) 3D printed CSB. Reproduced from Ref. [226,228] with permission from Elsevier, Copyright 2020 and 2022. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 20 6.2. Main materials and geometries Structural batteries are composed of five key components: anode, cathode, electrolyte, separator, and collector. However, as uncoupled structural battery electrode materials are predominantly used in as same as commercial batteries. So, the technology is wellestablished, this section will not delve into extensive detail on that aspect. Instead, the focus will be on coupled structural batteries. (1) Anode. The main forms of anodes in CSB can be categorized into two approaches. The first involves directly using CF as anodes. A notable example is developed by Leif’s research group at Chalmers University of Technology [229,230], which employs ultrathin Fig. 14. a) and b) structural battery anode. Reproduced from Ref. [230,233] with permission from Wiley and Royal Society of Chemistry, Copyright 2022 and 2020. c) Structural battery cathode. Reproduced from Ref. [229] with permission from Wiley, Copyright 2024. d) GPE. Reproduced from Ref. [249] with permission from American Chemical Society, Copyright 2021 e) Heterogeneous electrolyte and the corresponding SEM micrographs Reproduced from Ref. [250] with permission from Royal Society of Chemistry, Copyright 2013. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 21 unidirectional (UD) tapes made from polyacrylonitrile (PAN)-based CFs, as illustrated in Fig. 14a). To optimise the selection of CF, Kjell [231] and Snyder [216] evaluated the factors influencing the reversible capacity, microstructure, and the mechanical–electrical properties of common commercial CF, ultimately identifying the model with the best performance. The second approach utilizes conventional active materials such as graphite [232–235], which are mixed with binders and conductive agents to form a slurry. This slurry is then coated or deposited onto a CF collector, as shown in Fig. 14b). It is worth noting that the insertion and extraction of lithium ions into and from the electrode during electrochemical cycling (lithiation and delithiation) can cause volume changes of the active material. Especially for carbon materials, the volume expansion is approximately 10 % [236,237]. Conventional metal collectors do not experience changes in volume or modulus, which leads to interlayer mismatch strain and high stress concentration between electrodes. In severe cases, this can result in the delamination and peeling of electrode materials from the metal current collectors, ultimately causing electrode structure failure. Such failure significantly affects the electrochemical processes within the electrode and leads to a decline in electrode cycling performance and reduced battery lifespan [238–240]. In composite electrode structures where CF is used as the collector, the fibre has a disordered core surrounded by a graphite sheath and can also undergo lithium insertion. The expansion and contraction of CF as an electrode material during battery cycling can induce stress changes of CF. The lateral expansion of fully-lithiated CF is around 10 %, while the longitudinal extension along the fibre axis is about 1 % [241]. Mao et al. [242] studied the lithium insertion-induced deformation behaviour of dual graphite-CF electrodes during electrochemical cycling and developed a theoretical model of electrochemical stress for a bi-layer electrode cantilever structure. Their findings demonstrated that CF, when used as a collector, can effectively mitigate electrode volume expansion mismatch strain. (2) Cathode. The design of the cathode in structural batteries is relatively straightforward. In most cases, a cathode active material is mixed into a slurry and applied to CFs. For instance, Park [243] mixed LFP with polyvinylidene fluoride (PVDF), dried the mixture, and then added it to N-methylpyrrolidone (NMP), stirring the components to form a mud-like electrode slurry. This slurry was coated onto woven carbon fibre (WCF) and treated with silicone rubber in a high-pressure reactor within a vacuum bag to form the cathode. As shown in Fig. 14c), the electrode achieved a maximum capacity of 114 mAh.g −1 at a rate of 0.1C. Additionally, the LFP/WCF single electrode, measuring 35 mm ×5 mm, demonstrated a tensile strength of 250 N. (3) Electrolytes and separators. Some structural batteries retain the traditional design of separators and liquid electrolytes. For instance, Ladpli et al. [224,225,232–235] utilized liquid electrolytes in various battery systems, including conventional lithium salts like LiPF 6 or electrolyte solvents dissolved in organic compounds such as ethylene carbonate (EC), diethyl carbonate (DEC), and dimethyl carbonate (DMC). In these systems, the separators are immersed in the electrolyte solution. The separators are typically made of polypropylene or glass fibre. For structural batteries, an electrolyte that provides both structural support and ion transport channels is essential. SSE offer several advantages over liquid electrolytes, as they are less prone to issues such as corrosion, combustion, leakage, and internal short circuits. Additionally, they are inert to metallic lithium and can act as separators while also helping to suppress dendrite growth [244,245]. One type of solid electrolyte is gel polymer electrolyte (GPE), which is formed by expanding a thinly-crosslinked thermoset polymer with a liquid electrolyte [246]. For example, Tikekar’s research [247] demonstrated that fixing only a small portion (5 %) of anions on the membrane can inhibit dendritic growth by more than 20 times. Some structural cells utilize gel electrolytes. For instance, Liu et al. [248] used a polymer blend of PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene) and polyethylene glycol dimethacrylate to form a high-strength polymer gel electrolyte with LiPF 6 electrolyte solution. Chen added monomer PVA to the ZnCl 2 and MnSO 4 electrolyte and injected it into a fibre film to create a solid electrolyte. Dong et al. [249] mixed and ground PEO, lithium aluminium titanium phosphate (LATP), and LiTFSI powders into a thin SSE layer, which was then fused with a glass fibre separator through hot pressing, as shown in Fig. 14d). This electrolyte material exhibited a high Young’s modulus of 1.62 GPa and a conductivity of 6.3 × 10 −2 mS cm −1 at 25 ◦C, with conductivity increasing as the temperature rises. Another is heterogeneous electrolyte, comprising a uniform bi-continuous network of two pure phases, one phase for mechanical properties (monomers) and the other for ion transport (electrolytes) as shown in Fig. 14e). While high concentrations of lithium salts can improve the ion conductivity of polymers but reduce mechanical strength. To address this, Shirshova et al. [250,251] investigated the relationship between conductivity and Young’s modulus by adjusting the volume/weight ratio of monomers to electrolytes, identifying the optimal balance between mechanical strength and ion transport. A systematic study on electrolyte structure was carried out by the Chalmers University of Technology and the KTH Royal Institute of Technology team. Ihrner et al. [252] combined dimethyl methylphosphonate (DMMP) with LiTFS and cured it with ultraviolet light to form a solid-state electrolyte (SSE) film on the outer layer of CFs. The Young’s modulus is about 0.5 GPa and ion conductivity is 0.2 mS cm −1 . The following year, Johannison et al. [220,253,254] made further improvements by using different materials to create a uniform, low-viscosity solution. This solution was then vacuum-assisted and applied to CFs, followed by UV curing at 100 ◦C for 3.5 min to form a half-cell electrode. This process increased conductivity to 0.3 mS cm −1 , and the elastic modulus to 0.69 GPa. As structural batteries are typically composed of sealed and opaque materials, ultraviolet radiation is not always effective for curing. Subsequently, Schneider et al. [255] improved this electrolyte solution, which could be heated to form a solid electrolyte with a conductivity of 0.15 mS cm − 1, showing great promise for use in composite structural batteries. Schneider’s group later applied this electrolyte to produce high-performance composite structural batteries [256]. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 22 6.3. Figures of merit and functional characteristics The evaluation of structural batteries can be approached from two key aspects: electrical performance and mechanical performance. Electrical performance is typically characterized by battery capacity, while mechanical performance is assessed through various mechanical tests, including conventional methods such as tensile, compression, and bending tests. (1) Electrical performance. The energy density of various reported structural batteries has been compared as shown in Fig. 15. Batteries 1–5 represent uncoupled structural batteries, while 6–11 are coupled structural batteries. Uncoupled structural batteries 1 and 2 consist of commercial batteries embedded in CF or CF-foam sandwich structures, whereas batteries 3, 4, and 5 were prepared in the laboratory, where the battery packaging was directly replaced with CF. It is evident that these batteries exhibit much higher energy densities compared to other types. In particular, Ladpli et al. [232] used carbon fiber reinforced polymer (CFRP) laminates to replace traditional battery packaging, reinforcing the electrode stacks mechanically with interlocking polymer rivets. Their battery featured multi-layer electrodes, fixed by polymer rivets and clamped between CFRP panels, achieving an energy density of up to 130 Wh/kg. Dong et al. [257] ’s structural battery, designed with a self-supporting LFP (SS-LFP) cathode, incorporates LFP particles uniformly distributed within the SS-LFP cathode, surrounded by MXene nanosheets, CNTs, and cellulose, enhancing both electron transfer efficiency and structural stability, resulting in a high energy density. Coupled structural batteries also demonstrate strong electrical performance. For instance, Chen et al. [223] developed a Zn-MnO 2 battery, and Moyer et al. [234] created a lithium battery, both of which involve depositing or coating electrode slurry onto a CF current collector, significantly reducing the weight of the battery. Scholz et al. [258] suggested that battery for small electric aircraft would require a minimum energy density of 51.8 Wh/kg. Several structural batteries can meet or exceed this requirement, showcasing promising potential for future applications. (2) Mechanical performance. Based on reported mechanical properties in the literature, the electrical performance of structural batteries has been compared with commercial batteries. Due to the varying sizes and strengths of these batteries, elastic modulus or stiffness was chosen as the basis for comparison. As listed in Table 2, both forms of structural batteries have significantly enhanced mechanical performance. To date, the coupled structural battery produced by Richa et al. [229] demonstrates the best mechanical performance. The structural battery boasts an elastic modulus exceeding 76 GPa, an energy density of 30 Wh/kg, stability for up to 1000 cycles, and a coulombic efficiency of nearly 100 %, achieving a balance between energy and mechanical performance. Structural batteries with excellent mechanical properties are often analyzed to ensure the continuity and integrity of the structure. Coupled structural batteries, particularly those using heterogeneous electrolytes or packaged with CF, exhibit superior mechanical performance. However, due to a lack of adhesion Fig. 15. Comparison of the energy density of structural batteries [222,223,225,229,232–235,257,259,260]. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 23 between electrode materials, these batteries are susceptible to interface debonding, delamination damage, and other issues during mechanical loading [261,262]. These challenges can lead to a lower modulus, reduced energy storage capacity, and diminished electrical performance. (3) Multifunctional coefficient. However, the electrical performance of most structural batteries is still far below traditional batteries capacity, but their mechanical performance has improved by thousands or even higher. Therefore, in order to verify if it is worth to sacrifice electrical performance to improve mechanical performance, O’Brien et al. [264,265] proposed the concept of multifunctional efficiency of overall system performance to compete design criteria between the electrochemical and mechanical properties of structural batteries. Table 2 Comparison of mechanical properties of structural batteries. Reference Catergory Mechanical propties Value Elham [263] lithium polymer pouch cells Young’s ModulusShear modulus 180 Mpa 300 MPa Goal [222] DSB Flexural modulus 12.8 ±0.48 GPa Thomas [259] DSB Bending stiffness 985 ±31 N⋅m 2 Dong [257] DSB Flexural modulus 42.1 GPa Ladpi [232] DSB Flexural Rigidity. 12 N⋅m 2 Mao [225] DSB Flexural modulus 7.7 GPa Chen [223] CSB Young’s ModulusFlexural modulusCompressive modulus 12.8 Gpa4.4 GPa5.0 GPa Moyer [234] CSB Young’s Modulus 1.8 GPa Han [260] CSB Young’s Modulus 13.07 Gpa Richa [229] CSB Young’s Modulus 76 GPa Fig. 16. A) CSB in EV application. Reproduced from Ref. [267] with permission from Elsevier, Copyright 2020, b) integrating CSB within a 1U CubeSat. Reproduced from Ref. [241] with permission from Elsevier, Copyright 2013, c) CSB in hybrid aircraft (CS-23). Reproduced from Ref. [273] with permission from American Society of Civil Engineers, Copyright 2020. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 24 Multi functional efficiency is divided into the ratio of energy density and modulus (or stiffness) to that of a single functional system, η e and η s (equations (1) and (2). η e=Γmf Γ(1) η s=Emf E(2) The sum of two ratios is the multifunctional efficiency, and each term cannot be 0. When the multifunctional coefficient is greater than 1, it means that the multifunctional system has achieved an improvement in the balance of electromechanical performance (equation (3), η mf ≡ η s+ η e>1 (3) Snyder et al. [266] further enhanced the multifunctional coefficient by taking into account that structural batteries often employ anisotropic materials. In such cases, the modulus can be replaced by plane shear stress or shear modulus, and the minimum value of stress or modulus in each direction of anisotropy should be selected for comparison. Similarly, the electrical coefficient should be calculated by choosing the minimum value of energy density and specific power. Johannison et al. [220] introduced a new multifunctional coefficient to evaluate the weight savings of structural batteries, assuming that these batteries possess the same mechanical stiffness as traditional CFRP laminate under specific loads. Additionally, they assumed that both structural batteries and standard lithium-ion batteries store an equal amount of electrical energy. If based on this situation, the structural battery has a lower mass than the combined mass of the laminated panel and battery, it indicates that the structural battery outperforms the traditional single-function panel and battery. 6.4. Applications David Carlstedt and Leif E. Asp [267] evaluated the potential application of structural batteries in EVs based on their designed battery structure [246]. Using the BMW i3 and Tesla Model S as examples, as illustrated in Fig. 16a), they assumed the complete removal of all traditional batteries from the vehicle. In their scenario, 70 % of the inner and outer panels, as well as 60 % of the space frame and lifespan module, were replaced by their heterogeneous electrolyte structural battery. This modification resulted in a mileage increase of approximately 70 %, while maintaining the vehicle’s original weight. Reza et al. [268] conducted a similar study, using the Tesla Model S as a case example. They proposed that by replacing components such as the roof and hood with structural batteries, the vehicle’s mileage could increase by 23 %, all while maintaining good mechanical performance. CubeSats are a type of microand nano-scale scientific research spacecraft that utilize novel packaging and integration methods, multifunctional composite structures, embedded microsystems, and miniaturized propulsion systems. They are employed in various applications such as small payload delivery, rendezvous and docking operations, and satellite constellation arrangements in low Earth orbit (LEO) [269]. Typically, CubeSats have a standard size of 10 ×10 ×10 cm 3 and weigh 1.33 kg, known as 1U (one unit), as illustrated in Fig. 16b) [270]. Due to their small size and modular nature, CubeSats help reduce costs while presenting greater technological innovation challenges for system integration, miniaturization, multifunctionality, and intelligence. Batteries are critical to CubeSat operation, as the average daily power generation and consumption of onboard solar panels range from 2 to 6 W, necessitating energy storage for operations during periods of solar eclipses. To increase payload capacity and maximize usable space, CubeSat power systems have increasingly adopted new energy storage technologies, especially lithium-ion batteries. Batteries typically account for about 13 % of the total CubeSat mass. Moyer et al.[234] demonstrated that integrating CSB within a 1U CubeSat frame reduced battery mass by 30 % and increased available space, aligning CubeSat designs more closely with NASA’s operational requirements for mission injection. In terms of aircraft, Thomas et al. [271,272] designed and developed lithium cobalt oxide (LiCoO 2 )-graphite batteries, which were encased in DaiNippon EP-40 and used as structural wing materials for drones. This innovation allowed drones to increase their flight time by up to 26 %, while maintaining the same specific energy as traditional battery structures. Riboldi et al. [273] investigated the use of CSBs in hybrid aircraft (CS-23), incorporating them into 38 % of the wings and 66 % of the fuselage, as shown in Fig. 16c). They found that, while maintaining the original power performance, the overall weight of the aircraft structure and battery could be reduced by approximately 20 % compared to traditional carbon fibre-reinforced polymer (CFRP) structures, and by about 29 % compared to aluminium alloy structures with traditional battery packs. Mauro et al. [274] expanded on this research by replacing 38 % and 75 % of the wing and fuselage structures with structural batteries for the P2012 Traveller aircraft. This resulted in a fuel savings of approximately 18 % for the design mission (1100 km) and 20 % for a typical mission (370 km). Elitza et al. [275] examined the A320 aircraft and found that replacing 50 % of the fuselage with CSBs could increase fuel efficiency by 15 % during a 1500 km mission, compared to the traditional hybrid A320. Compared to a fully electric A320, structural batteries could halve the specific energy or mass required for 1000 km of flight. In another case, Sang et al. [276] replaced the floor of the Airbus A220-100 with a clip-on CSBs to power the in-flight entertainment system. This modification saved approximately 260 kg in weight and 510 L in volume. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 25 constructing printed electrodes with macroand microscopic 3D porous structures [310,316,317]. Graphene oxide (GO), in particular, offers beneficial properties for designing 3D printable electrode inks. The numerous oxygen-containing functional groups on the GO surface enable high dispersion in aqueous solutions. Furthermore, GO can achieve high electrical conductivity after reduction (i.e., reduced-GO). Lacey et al. introduced holey graphene oxide (hGO) as a hierarchically porous cathode for Li-O 2 batteries utilizing 3D printing (Fig. 19d) [304]. The trimodal porosity—nanoscale (4–25 nm on hGO sheets), microscale (tens of micrometer-sized pores introduced by freeze-drying), and macroscale (<500 μ m square pores of the mesh design by 3D printing)—enables full active-site utilization of the air electrodes. Electrolyte-embedded printable composite electrodes present a fascinating alternative by incorporating a liquid-state electrolyte precursor as the dispersion solvent for electrode inks. This approach ensures that the electrolyte-containing electrodes remain free from structural collapse and component migration issues during the drying process. Kim et al. and their colleagues have reported a series of electrolyte-embedded printable electrodes, demonstrating their versatility across various electrochemical systems. For instance, printable LIB electrodes have been successfully produced via the stencil printing technique. These electrodes comprise electrode powders (e.g., LCO or LTO and a conductive agent) and a UV-curable solid-state gel electrolyte precursor ink (composed of lithium salt and carbonate/nitrile solvent with acrylate monomers) [288,318]. This type of printable electrode has also been successfully utilized to demonstrate a printed Li-S battery [305]. Two thermodynamically immiscible and nonflammable gel electrolytes, derived from ethyl methyl sulfone and tetraethylene glycol dimethyl ether, were employed to address longstanding concerns related to the polysulfide shuttle effect (Fig. 19d). 7.3.1.2. Sodium-/zinc batteries. While lithium batteries offer several advantages, they also have significant drawbacks, such as high material costs and safety concerns, leading to increased interest in post-lithium battery systems. Sodium-ion batteries (SIBs) have attracted considerable attention recently owing to their abundant sodium resources, lower cost, smaller solvation shell, and operational principles similar to those of lithium-ion batteries. However, Na + ions (1.02 Å) are larger than Li + ions (0.76 Å), leading to phase instability in the electrode active materials during electrochemical reactions. Moreover, sodium is heavier than lithium (23 g mol −1 vs. 6.9 g mol −1 ) and has a higher standard electrode potential (−2.71 V vs. SHE compared to −3.02 V vs. SHE for lithium), which results in a lower energy density for sodium-ion batteries compared to lithium-ion batteries [319–321]. To address these challenges, much research has focused on increasing the energy density and material stability of active materials. Recently, 3D-printed SIBs have been demonstrated with 3D interconnected conductive thick microelectrodes, achieving ultrahigh areal capacity and enhanced rate capability [306]. The 3D-printed SIB electrodes, featuring adjustable viscosity and superior rheological properties, were composed of well-dispersed high-capacity Na 3 V 2 (PO 4 ) 2 O 2 F or high-rate carbon-coated NaTi 2 (PO 4 ) 3 , along with highly conductive additives such as 2D electrochemically exfoliated graphene (EG) nanosheets and 1D carbon nanotubes (CNTs) (Fig. 19f). Zn-ion batteries (ZIBs) have recently garnered significant attention owing to the abundance of zinc, which provides a high theoretical capacity (820 mAh g Zn -1 ) and cost-competitive cell fabrication [322,323]. Notably, utilizing aqueous electrolytes ensures excellent safety compared to organic electrolytes, making ZIBs suitable for human-oriented applications such as wearable devices and implantable electronics. Furthermore, aqueous electrolytes are advantageous for various printing techniques because they do not require a dehumidified environment (i.e., dry room). Recently, Ahn et al. reported on-demand conformal (ZIB) on non-developable surfaces utilizing DIW-based nonplanar 3D printing (Fig. 19g) [307]. The manganese dioxide (MnO 2 ) cathodes consisted of α -MnO 2 nanorod active particles, carbon black (CB)/multi-walled carbon nanotube (MWNT) conductive additives, and Tempo-oxidized cellulose nanofiber (TOCN) as an anionic 1D binder. The TOCN binder effectively enhanced dispersion state via non-covalent hydrophobic attraction and interparticle electrostatic repulsion. Zn particles were combined with activated carbon (AC) for the anodes to improve Zn plating/stripping cyclability because of their highly developed micropores. The rationally designed ZIB component inks enable geometrical matching of the printed batteries with arbitrary curvilinear substrates without experiencing deformation strain. Liquid metal is another fascinating candidate for fabricating printable electrodes owing to its liquid state, which ensures high printability and electrical conductivity comparable to conventional metals. Recently, eutectic gallium-indium (EGaIn) has been introduced as a structuring agent for Zn anodes in ZIBs, leveraging the unique physical properties of liquid metal, such as extremely high surface tension and high electrical conductivity [324]. A 3D-printed polyacrylamide-hemicellulose/EGaIn microdroplet hydrogel was developed as a self-standing scaffold [308]. This EGaIn-based hydrogel acted as an electrically and ionically conductive microporous matrix, enabling isotropic deposition of Zn 2+ to form a stable anode host capable of stress dissipation (Fig. 19h). It was confirmed that the EGaIn-based hydrogel exhibits a double-covalent hydrogen-bonding system with self-healing and shear-thinning behavior, which is crucially advantageous for preventing liquid metal loss and facilitating 3D printing processes. 7.3.1.3. Supercapacitors. Supercapacitors are the most widely adopted electrochemical systems in printable power sources owing to their ease of fabrication, material versatility, long cycle life, and fast charging/discharging rates. Previous studies have employed various printing techniques for printable supercapacitors, including stencil [325], spray [326,327], inkjet [309,328,329], EHD jet [292], dispenser [330], 3D [331–335], and stamping [336]. Inkjet printing is one of the most frequently utilized methods to fabricate the printed supercapacitors owing to its capability for monolithic integration with inkjet-printed electronics. Choi et al. successfully function of printed layers. Reproduced from Ref. [312] with permission from Wiley-VCH GmbH, Copyright 2019. m) A photograph of the MXene ink with various organic solvents. Reproduced from Ref. [313] with permission from Nature Publishing Group, Copyright 2019. n) (left) A SEM image of 3D-printed N-Ti 3 C 2 T x electrodes featuring abundant open pores, and (right) Schematic representation showing charging process of the n-Ti 3 C 2 T x // activated carbon hybrid capacitor. Reproduced from Ref. [314] with permission from American Chemical Society, Copyright 2020. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 32 integrated inkjet-printed supercapacitors onto A4 paper coated with a CNF nanomat-based primer to achieve high printing resolution [309]. To enhance electrical conductivity, the printed electrodes, composed of SWNT and AC, also functioned as a sintering agent for silver nanowires, in which the SWNT are exploited as UV light absorbers and hear-transfer pathways. Although supercapacitors are attractive electrochemical systems for printable power sources, they have conventionally suffered from low energy density. To address this issue, many studies have focused on 3D-printed supercapacitors with thick electrodes to increase their areal energy density [331–335]. Tang et al. demonstrated the 3D printing of graphene-based aerogels for supercapacitors, achieving various arbitrary predesigned architectures and out-of-plane patterns on curved surfaces via mixed-dimensional materials (e.g., 0D quantum dots, 1D nanowires/nanorods, 2D boron nitrides, carbon nitrides, and transition-metal carbide nanosheets) (Fig. 19j) [310]. Furthermore, 3D-printed quasi–solid-state asymmetric MSCs with a high areal energy density of 73.9 μ Wh cm −2 were demonstrated (Fig. 19k). They utilized vanadium pentoxide (V 2 O 5 ) for the cathode and graphene-vanadium nitride quantum dots (G-VNQDs) with highly concentrated GO-based anode inks, achieving electrode thicknesses exceeding 400 μ m [311]. To achieve extremely high energy density, Gao et al. presented supercapacitor electrodes with a woodpile configuration, achieving an ultrahigh thickness of 3D-printed electrodes [312]. Their ten-layer printed electrodes exhibited a thickness of 2220 μ m, resulting in an areal capacitance of 4.56F cm −2 and an areal energy density of 0.63 mWh cm −2 . MXene has recently garnered significant attention as a high-capacitance material. The most extensively researched MXene, titanium carbide (Ti 3 C 2 T x , with T x representing the functional groups that terminate the structure), boasts a high electronic conductivity of up to approximately 10,000 S cm −1 and a surface chemistry similar to TiO 2 , exhibiting extremely high volumetric capacitance (~1500F cm −3 ). Zhang et al. demonstrated two types of MXene ink for both inkjet and dispenser printing to fabricate MSCs [313]. The negative surface charge on the hydrophilic Ti 3 C 2 T x nanosheets enabled a stable dispersion state in both aqueous and organic inks without adding surfactants or polymer stabilizers (Fig. 19m). Owing to the surface moieties of the MXene, a nitrogen-doped Ti 3 C 2 T x (N-Ti 3 C 2 T x ) was synthesized for the anode of sodium-ion hybrid capacitors (Fig. 19n) [314]. The 3D-printed N-Ti 3 C 2 T x electrodes feature abundant open and hierarchical pores, facilitating ion/electrolyte transport and accommodating volume changes during cycling. As a result, the 3D-printed hybrid capacitors exhibited high areal mass loading up to 15.2 mg cm −2 and areal energy density of 1.18 mWh cm −2 . 7.3.1.4. Electrolyte or separator. Another key component of printed batteries is the printable electrolyte, which plays a crucial role in the design and flexibility of the resulting devices. Despite their important role as a medium for electrochemical reactions, electrolytes have not advanced as much as electrodes in the development of printed batteries [282,285]. Due to their fluid nature, conventional liquid electrolytes necessitate rigid and bulky packaging, which significantly hinders the shape diversity, safety, and miniaturization of printed batteries. Given these limitations, the focus has shifted to solid-state electrolytes, which can be classified into organic and inorganic categories. Each type of solid-state electrolyte has its own physical and electrochemical characteristics that affect the fabrication processes and battery performance. 7.3.1.5. Inorganic solid-state electrolyte. Owing to their inherent single-ion conducting properties and the improvements in their ionic conductivity, solid inorganic electrolytes, especially those based on sulfides and oxides, have garnered substantial research interest [337,338]. However, severe interfacial issues and the necessity for harsh post-treatments (e.g., thermal sintering or mechanical pressing) pose hurdles in demonstrating printable solid-state electrolytes. Poor contact between the electrodes and electrolytes also results in increased internal cell resistance. To address this issue, McOwen et al. demonstrated the 3D-printed electrolyte comprising Li 7 La 3 Zr 2 O 12 (LLZ) to enlarge contact area between the Li-metal electrodes and the electrolytes [339]. Based on the physical properties of binder materials, two types of printable LLZ inks were designed: self-supporting and conformal ink (Fig. 20a), which were utilized according to the final shape of the printed electrolytes. Hence, Li-metal symmetric cells with the 3D-printed LLZ electrolyte exhibited dramatically lower full-cell resistance and higher energy density (Fig. 20b and c). One of the major drawbacks of oxide solid-state electrolytes is that the harsh sintering conditions (500–1100 ℃) required to ensure moderate ionic conductivity result in severe lithium loss [348]. To address this issue, Ping et al. presented a printing and radiative heating fabrication method that allowed for the thin-film deposition and quick sintering of Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 solid-state electrolytes (Fig. 20d and e) [340]. The printed garnet electrolyte film exhibited a high Li ionic conductivity up to 10 -3 S cm −1 , which is comparable to that of garnet bulk electrolyte. Sulfide solid-state electrolytes are an attractive candidate for printable electrolytes owing to their high ionic conductivity (10 2 –10 3 S cm −1 ) and ease of solution processability. Several studies have successfully demonstrated solution-processable sulfide solid-state electrolytes utilizing various fabrication techniques, highlighting their potential as printable electrolyte materials (Fig. 20f) [341,349]. 7.3.1.6. Organic solid-state electrolyte. Organic material-based solid-state electrolytes offer several advantages over inorganic ones, including ease of processability, mechanical flexibility, and intimate interfacial contact with electrodes. Generally, printable organic solid-state electrolytes comprise an ion-conducting medium (e.g., liquid electrolyte or polar polymer with salts) and a mechanical skeleton (e.g., polymer matrix or ceramic filler) mixed with a dispersing solvent. Typically, the printed electrolytes undergo a drying process to remove the dispersing solvent [282,285]. However, this drying process can induce unwanted shrinkage, resulting in structural disruption. UV-assisted in-situ solidification of electrolyte inks is a facile method for developing scalable printable solid-state electrolytes without needing solvent drying (Fig. 20g). Various UV-curable printed solid-state electrolytes have been demonstrated to exhibit moderate ionic conductivity and excellent electrochemical performance. These electrolytes utilize a wide range of materials, such as C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 33 Fig. 20. a) A photograph of two-type of 3D-printable LLZ electrolyte ink deposited onto a tilted substrate. b) Schematic of Li-filled pores between 3D-printed LLZ grid in a stacked-array pattern on LLZ substrate. c) Cross-sectional SEM image of 3D-printed LLZ//Li metal interfaces. Reproduced from Ref. [339] with permission from Wiley-VCH GmbH, Copyright 2018. d) Photographs showing (d) appearance and e) printing processes of printable LLZTO solid-state electrolyte inks. Reproduced from Ref. [340] with permission from American Association for the Advancement of Science, Copyright 2020. f) Schematic representation of solution-processible sulfide solid-state electrolyte. Reproduced from Ref. [341] with permission from Wiley-VCH GmbH, Copyright 2018. g) Schematic of the procedure used to fabricate the stencil-printed solid-state electrolyte using UV-assisted in-situ solidification. Reproduced from Ref. [288] with permission from Royal Society of Chemistry, Copyright 2018. h) Microcomputed tomography (Micro-CT) image of UV-curable 3D-printed solid-state electrolyte infiltrated into interstitial voids between the 3D-printed adjacent electrode layers. Reproduced from Ref. [342] with permission from Wiley-VCH GmbH, Copyright 2022. i) Schematic representation of SLA 3D-printed solid polymer electrolyte. Reproduced from Ref. [343] with permission from Wiley-VCH GmbH, Copyright 2020. j) Schematics of printable single-ion conducting quasi-solid-state soft electrolyte. Reprinted with permission from [344]. Copyright 2021, Wiley-VCH GmbH. k) C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 34 High-resolution transmission electron microscopy (HRTEM) image showing the FLS-based printable Ni current collectors. Reproduced from Ref. [345] with permission from Wiley-VCH GmbH, Copyright 2020. l) Schematic showing the 3D printing and FLS process of 3D printable Cu circuit. Reproduced from Ref. [346] with permission from Wiley-VCH GmbH, Copyright 2020. m) Photographs showing the printing process and printed electric circuit using substrate-versatile CNT ink. Reproduced from Ref. [347] with permission from Wiley-VCH GmbH, Copyright 2021. Fig. 21. Shape-versatile power sources. a) Cross-sectional SEM image of the printed bipolar cells, where three cells were connected in series, along with a schematic illustrating their structure. The Al foil is a common current collector shared between the LTO anode and LCO cathode. b) The charge/discharge profiles of the printed bipolar cells connected in series as a function of cell number (under charge/discharge current density of 0.1C/0.1C). c) Sequential photographs depicting the stepwise fabrication of the printed bipolar two-stacked cell on the curved roof of a miniature toy car. Reproduced from Ref. [288] with permission from The Royal Society of Chemistry, Copyright 2018. d) Bipolar ASSLSB in the shape of ’UNIST’ letters (two cells connected in series) directly fabricated on a toy aircraft’s surface. Photographs demonstrating the operation (LED and propeller) of the printed bipolar ASSLSB in the toy craft. Reproduced from Ref. [305] with permission from Wiley-VCH GmbH, Copyright 2019. e) Schematic of 3D-printed interdigitated micro-LIBs. f) Photograph of LFP/GO and LTO/GO inks in syringes. g) Digital images of micro-scale 3Dprinted electrodes. Reproduced from Ref. [316] with permission from Wiley-VCH GmbH, Copyright 2016. h) Cross-section SEM image of the interdigitated electrodes, alternatively electroplated V 2 O 5 cathode and lithium metal anode for Li-ion micro-batteries. i) Red micro-LED powered by a packaged cell. Reproduced from Ref. [353] with permission from Wiley-VCH GmbH, Copyright 2021. j) Photographs of on-chip UHD SS–MSCs (36 unit cells in series) with an area of 8.0 ×8.2 mm, smaller than a coin. Inset: optical microscopy image of a unit cell in the UHD SS–MSCs. Reproduced from Ref. [292] with permission from American Association for the Advancement of Science, Copyright 2020. k) GCD profiles of TNPMSC configured with nine unit cells connected in series (3S) and in parallel (3P) in a combined 3S ×3P arrangement. The inset depicts a photograph of a micro-LED powered by the MSC. Reproduced from Ref. [299] with permission from Wiley-VCH GmbH, Copyright 2022. l) Photographs of the accordion-foldable MSC and the compact arrangement of its constituent cells. Reproduced from Ref. [330] with permission from Wiley-VCH GmbH, Copyright 2023. m) Photograph of flexible M−MIMSCs containing 400 cells. Reproduced from Ref. [354] with permission from Oxford University Press, Copyright 2023. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 35 carbonate-, ether-, or nitrile-based liquid electrolytes as the ion-conducting medium, tri-acrylate UV-curable monomers, and linear polymers as the mechanical skeleton, and ceramic fillers as rheology modifiers [288,305,341,350,351]. Because of the ease of the solidification process and material versatility, UV-curable solid-state electrolytes are beneficial for fabricating 3D-printed solid-state batteries [302,307,352]. Lee et al. presented ionic liquid-based UV-curable 3D-printed solid-state electrolytes that enable dense infiltration into interstitial voids between the 3D-printed adjacent electrode layers [342]. The click-cross-linkable thiol-ene monomers quickly solidified the electrolyte inks after UV irradiation, which exhibited stable mechanical integrity without any collapse or unwanted void (Fig. 20h). The material versatility of printable organic solid-state electrolytes can also be leveraged to enhance electrochemical performance. He et al. demonstrated stereolithography 3D-printing of a solid polymer electrolyte composed of lithium salt, succinonitrile, and poly (ethylene glycol) diacrylate [343]. The 3D-structured solid-state electrolyte successfully increased the contact area between the electrode and electrolyte, which reinforced interfacial adhesion, improved the mass loading of active materials, and enhanced mechanical strength (Fig. 20i). Furthermore, introducing single-ion conductive materials to printed solid-state electrolytes plays a crucial role in stabilizing the interfaces with electrodes. Recently, Oh et al. demonstrated a single-ion conducting quasi-solid-state soft electrolyte by utilizing a cationic copolymer-based ion-rectifying polymer and anion-trapping titanium/silica-modified alumina nanoparticles as the mechanical skeleton and rheology tuning agent, respectively (Fig. 20j) [344]. The single-ion conducting capability of the quasi-solid-state electrolyte enabled stabilizing the surface of the Li metal anode and LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode, thereby prolonging the cyclability of the printed solid-state lithium metal batteries. 7.3.1.7. Current collector. To realize an all-printed battery, one of the key printable components is the current collector. However, there has been relatively little research on printable current collectors compared to other components. Metal foil is commonly utilized as a current collector in conventional bulk-type batteries, but it severely limits design diversity when utilized in printed batteries. Although metal particles-based printable inks are an alternative candidate to demonstrate printed current collector, common metal species for the current collector, such as aluminum (Al) and copper (Cu), tend to be easily oxidated, and they require harsh posttreatment processes, including thermal sintering or chemical reduction to reduce contact resistance between the metal particles. To address these issues, printable nickel (Ni) current collectors were recently demonstrated through flash-light sintering (FLS) process in a timescale of 10 -3 s [345]. During the FLS process, the printed particulate layer composed of Ni flakes and Ni nanoparticles was converted into a metallic current collector with an electrochemically robust and conductive surface passivation layer (Fig. 20k). The printed Ni current collector exhibited stable electrochemical operation in printed MSCs with an operating voltage of 3 V. A similar approach was applied to printed Cu circuits, which demonstrated a resistivity of 15 μ Ω cm (corresponding to 670 kS m −1 ) (Fig. 20l) [346], exhibiting potential as an anode current collector for printed batteries. Carbon nanomaterials are typical alternatives to metal current collectors owing to their high electrical conductivity and good electrochemical stability without requiring additional post-treatments. Owens et al. presented a substrate-versatile printed CNT electric circuit with a conductivity of 10 kS m −1 (Fig. 20m) [347]. Owing to the mechanical properties of CNTs, the printed circuit exhibited excellent flexibility, exhibiting less than 3 % change in DC resistance with a bending radius down to 1 mm. 7.4. Applications of printed batteries for device-tailored energy storage solutions 7.4.1. Shape-versatile form factors As the demand grows across various industries for diverse forms of electronic devices in daily life, shape-versatile batteries are increasingly spotlighted for their ability. Recent research has explored printed solid-state batteries and supercapacitors, which provide superior shape adaptability and aesthetic versatility beyond conventional batteries technologies. 7.4.1.1. Bipolar configuration. Bipolar configurations, utilizing solid-state electrolytes, enable straightforward electrical connections between individual cells in a single package through shared current collectors. Combined with advanced printing techniques, unit cells can be systematically assembled into a stable structure within a limited space. This technique enables the achievement of high voltages and high volumetric energy densities with a customizable cell design. Kim et al. utilized stencil-printing and UV-light-assisted in situ processes to fabricate solid-state batteries [288]. They applied UVcuring-assisted multi-step printing to produce bipolar-stacked cells, where both stencil-printed anode and cathode shared an Al foil as a current collector. Fig. 21a) presents a cross-sectional SEM image illustrating a sequentially three-stacked bipolar cell featuring the battery components. The charge/discharge profile of series-printed bipolar cells depict a voltage increase from 2.4 to 7.2 V as the number of stacked cells increases (Fig. 21b). This multi-step printing technique enables the sequential printing of parallel bipolar cells on top of a target object (Fig. 21c). Similarly, printable bipolar all-solid-state Li-S batteries (ASSLSBs) have also been reported [305]. These ASSLSBs, configured in the shape of the letters and comprising two cells connected in series (3.0–5.6 V), are manufactured without solvent drying directly on the surface of a toy aircraft. The printed ASSLSBs successfully powered a light emitting diode (LED) and a propeller integrated with the toy airplane (Fig. 21d). 7.4.1.2. Micro power sources. The rapid advancement of portable and wearable electronics has heightened the demand for lightweight, compact, and integrated microscale power sources. Advanced printing techniques are crucial tools for developing these miniaturized energy devices. They are noted for their efficient space utilization, adaptability for device-specific integration, reliable C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 36 electrochemical performance, and capability for precise high-resolution electrode design. 3D-printed micro-scale LIBs with an interdigitated configuration of electrodes is a typical example of the micro power sources. (Fig. 21e) [316]. The rheology-tuned LFP/GO cathode and LTO/GO anode inks enable DIW printing (Fig. 21f). A micro-scale LIB was fabricated by injecting poly(vinylidene fluoride)–co-hexafluoropropylene (PVDF-co-HFP)-based solid-state electrolyte between the interdigitated electrodes. This configuration featured uniformly miniaturized electrodes with a high aspect ratio on a glass substrate (Fig. 21g). Sun et al. proposed a novel 3D-structured battery (Li metal anode/gel electrolyte/V 2 O 5 cathode) fabricated via imprint lithography for high-resolution micro-and nanofabrication [353]. Fig. 21h presents a cross-sectional SEM image of interdigitated microelectrodes. The electrodes are approximately 70 μ m wide, with gaps of around 20 μ m between them, demonstrating a highly precise microstructure. The packaged micro-battery exhibits an energy density of 1.24 J cm −2 and a power density of 75.5 mW cm −2 , successfully powering a red LED (Fig. 21i). EHD printing is stateof-the-art technique to fabricate micro power sources owing to its high printing fidelity. Leveraging the highprecision capabilities, MSCs with interdigitated electrodes with a 10-µm resolution were printed onto the chip substrate [292]. To further emphasize the architectural and electrochemical performance of the downsized on-chip MSC, they successfully fabricated 36 unit cells connected in series on a chip with an area of 8.0 mm ×8.2 mm, smaller than a coin (Fig. 21j). The areal number density of the MSC was approximately 60 cells cm −2 with an areal operating voltage of 65.9 V cm −2 . 7.4.1.3. Integrated configuration. Conventional energy storage devices typically comprise a sandwich-type stacked configuration. However, this structure restricts performance customization within a single substrate for each unit cell. To overcome this challenge, the stepwise printing technique facilitates the construction of multiple cells on a single substrate, enabling easy integration and electrical connection in series or in parallel. This approach enhances either output voltage or capacity, depending on the configuration. On-demand cell configuration could be easily demonstrated where nine unit cells of MSC were connected in series (3S) and in parallel (3P) to achieve tunable voltages and capacitances within a single transparent body (Fig. 21k) [299]. Via EHD printing, various micro-scale electrode structures were fabricated on a transparent nanocellulose paper with UV-curable mask ink. These structures were integrated with solid-state aqueous gel electrolytes that isolate MSC unit cells ionically, enabling the transparent power sources to maintain high transparency while offering customizable cell configurations. Fig. 22. Conformal power sources. a) Fabrication process of stencil-printed SC on T-shirts. b) Photograph of wearable electronic garments featuring SCs designed as a bulb symbol capable of operating LEDs. Reproduced from Ref. [325] with permission from Wiley-VCH GmbH, Copyright 2018. c) Photographs depicting the sequential fabrication and integration of conformal ZIB with human ear. d) Photograph of ear-shaped conformal ZIB connected to hearing aid connected with an LED, demonstrating successful operation of the LED and amplifier by the conformal ZIB. Reproduced from Ref. [307] with permission from Wiley-VCH GmbH, Copyright 2023. e) Schematic and photo images of a 3D DIW-printed LIB with packaging on an eyeglasses temple. f) Photographs of fabricated conformal printed battery onto 3D eyeglasses, powering connected micro-LEDs. Reproduced from Ref. [355] with permission from Elsevier, Copyright 2023. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 37 Lee et al. employed an accordion folding strategy to compactly integrate on-demand MSCs with a high-fill factor-based cell design [330]. The DIW process of the metallic MoS 2 -based inks allows for microscale manufacturing of MSCs with multiple integrated electrodes. This enables on-demand (in series/in parallel) in a footprint of 22.75 mm 2 and a thickness of 0.8 mm. The integrated 12 MSC unit cells achieve a high space utilization and demonstrate an areal capacitance of 180.7 mF⋅cm −2 and an areal energy density of 89.2 μ Wh⋅cm −2 (Fig. 21l). Recently, Wang et al. proposed a practical multi-step lithographic patterning and spray printing method for Ti 3 C 2 T x MXene-based microelectrodes.[78] They developed a mass production for these micro-electrodes, effectively enhancing the integration level with the high cell density of MXene-MSCs. By connecting 334 cells and precisely 3D printing the polyvinyl alcohol/H 2 SO 4 (PVA/H 2 SO 4 ) gel electrolyte, they achieved an extremely high voltage of 200 V in a small area of 3.5 cm ×3.5 cm (Fig. 21m). 7.4.1.4. Target-oriented applications. This chapter presents studies that have implemented specific target-oriented power sources, including conformal power sources, monolithic integration with devices, printed frameworks for Li-metal batteries, and 3D structural electrodes for high-mass loading. Building upon the materials and printing technologies discussed in earlier chapters, we review typical examples of printed batteries that ensure stable operation and enhance the electrochemical performance of flexible and Fig. 23. Monolithic integration with devices. a) A diagram illustrating the direct printing of additive-free MXene aqueous inks at room temperature on diverse substrates, intended for flexible wireless electronics applications including sensors, MSCs, and antennas. b) Multi-functional pattern printed entirely with MXene for integrated electronics enabled with NFC. Reproduced from Ref. [356] with permission from Nature Publishing Group, Copyright 2022. c) Schematic depicting design of soft robot integrated with rechargeable power sources. d) Hand-shaped SL-PS with cells configured in series (3S) and in parallel (2P) at 100 ◦C autonomously morphing into a soft gripper. Reproduced from Ref. [327] with permission from Elsevier, Copyright 2022. e) Schematic of smart contact lens and DIW-based fabrication process of the monolithically integrated SC with an arc-shaped form factor. f) Photo of a person wearing soft smart contact lenses with operated LEDs. Reproduced from Ref. [357] with permission from American Association for the Advancement of Science, Copyright 2019. g) Photograph of printing-based cSiPV–bQSSB (h) Photo-charge and galvanostatic-discharge profiles of cSiPV–bQSSB with photo-charging from 3.0 to 5.4 V under 1-sun illumination, followed by galvanostatic discharge at a discharge current density of 0.1C. Reproduced from Ref. [358] with permission from The Royal Society of Chemistry, Copyright 2020. i) Photographic image displays the epidermal sweat sensing patch, illustrating instant target concentration readout (i), electrolyte concentration changes and sensor readout (ii), and the intermittent discharge mode of the Ag 2 O–Zn battery powering the system (iii). Reproduced from Ref. [359] with permission from Nature Publishing Group, Copyright 2022. j) Schematic of nonplanar 3D printed quasi–solid-state ZIMB for cranium electronics. k) Comparison of the weight between the cranium-customized ZIMB and conventional pouch-type ZIMB. l) Optical stereomicrograph of liquid metal-based neural interface on a mouse cranium (top) and ZIMB integration on the neural interface (bottom). Reproduced from Ref. [291] with permission from American Association for the Advancement of Science, Copyright 2024. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 38 wearable electronic devices tailored to specific applications. 7.4.1.4.1. Conformal power sources. Conventional batteries with rigid components are difficult to integrate seamlessly into wearable electronics. Direct integration into targe devices is most powerful advantages of the printed batteries. Lee et al. fabricated wearable SCs on cotton T-shirts via UV-assisted stencil-printing [325]. They utilized a commercial sewing machine to incorporate electrically conductive stainless steel threads as the current collector into the aesthetically designed structure. Then, electrode active ink (AC, MWNT, and ionic liquid) and ionic liquid-based UV-curable gel electrolytes were printed onto cotton to realize wearable energy storage textiles (Fig. 22a). Furthermore, they fabricated daily electronic garments employing a stencil printing method to create a bulb symbol. The printed SCs exhibit an areal capacitance of 15 mF⋅cm −2 and an output voltage of 3 V. They can operate the LEDs in various mechanical deformation modes and even when ironed at 140 ◦C (Fig. 22b). Implementing nonplanar printing on arbitrarily curved substrates is challenging because of the gravitational deformation of the printed ink. To address these challenges, Ahn et al. optimized the composition by designing colloidal interactions for conformal printing (described in the section on Sodium-/zinc batteries) [307]. Fig. 22c showed the stepwise fabrication and integration procedure of the conformal ZIB with a human ear. They also emphasized versatile printing technology by monolithic integrating ZIBs with the human ear and then connecting them to LED-equipped hearing aids (Fig. 22d). Recently, versatile-shaped electronics were successfully integrated within the scalable Li-ion system via the 3D DIW-printing technique, as illustrated in Fig. 22e [355]. The current collectors were printed conformally onto the desired target surface utilizing conductive silver and carbon paste. The rheological optimized LFP cathode and LTO anode inks were stably deposited on the surfaces of versatile-shaped objects, such as 3D eyeglasses. Subsequently, the LIB system was completed by sequentially printing a gel polymer electrolyte and UV-curable polydimethylsiloxane packaging ink, resulting in the successful illumination of micro-LEDs (Fig. 22f). Utilizing printable battery materials with sequential 3D DIW results in fully 3D-printed, shape-versatile batteries with a low device footprint. These conformal power sources offer a practical solution for powering specific applications, featuring flexible aesthetics, competitive electrochemical performance, and adaptable designs. 7.4.1.4.2. Monolithic integration with devices. Printed power sources provide optimal solutions for applications in flexible and wearable electronics, emphasizing mechanical properties and electrochemical performance in multifunctional devices. Combining energy storage systems with electronic devices and energy harvesting can sustainably power electronic devices without relying on external electrical charging. MXenes (Ti 3 C 2 T x ) have been widely employed in numerous studies as a key material for supercapacitors and electrical circuits, owing to their outstanding electronic conductivity and dispersion stability as described in the section on Supercapacitors. (Fig. 23a) [356]. The printed MXene-based wireless sensors platform (T/H sensor/MSC/NFC antenna) is presented in Fig. 23b). This study incorporated the printed MXene patterns into a flexible printed circuit board containing a microcontroller unit, NFC antenna, and matching network. This integrated system responded to temperature and humidity changes, wirelessly sending the power/data to smartphones for monitoring the microenvironment of plant growth. Soft electronics are garnering attention for their adaptability in complex environments, however, they encounter challenges such as restricted mobility due to tethered cords and bulky power sources. Recently, printed supercapacitors were monolithically integrated within an untethered soft robot to demonstrate light-triggered, shape-reconfigurable, and locomotive rechargeable power sources [327]. They fabricated supercapacitors utilizing flexible Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/ MWNT/solid-state gel electrolyte materials on a liquid crystalline polymer network (LCN) substrate via a dispenser printing process (Fig. 23c). The LCN-based soft robot demonstrates autonomous and reversible morphological changes upon exposure to light or heat without compromising the electrochemical performance of the power source. Experimental validation showcases its application as a soft robot, where the hand-shaped device exhibited stable capacitive behavior and reliably powered a red LED even as it autonomously transformed into a soft gripper at 100 ◦C (Fig. 23d). As an application for the implantable devices, printed solid-state supercapacitors were monolithically integrated into a soft, smart contact lens with wireless charging. (Fig. 23e) [357]. This precision fine arc-shaped SC was fabricated via a DIW process. The smart contact lens system, including an antenna, rectifier, and LED, was monolithically integrated via microfabrication techniques. The printed SCs possess enough energy density to power the LED within the confined 9-mm diameter of the lens (Fig. 23f). Interest in photovoltaics as a burgeoning energy-harvesting technology is rapidly growing. However, effective energy storage systems are indispensable for storing the harvested energy, and fully integrating these technologies poses substantial challenges. Recent advances have facilitated the development of integrated PV–battery systems utilizing printable solid-state LIBs. Kim et al. demonstrated printed bipolar quasi–solid-state LIBs (bQSSBs) with a bipolar cell configuration directly on the aluminum electrode of a crystalline silicon PV (cSiPV) module utilizing an in-series printing process [358]. This approach enables seamless architectural and electrical integration of PVs and energy storage systems (Fig. 23g). As depicted in Fig. 23h, the cSiPV–bQSSB system exhibited stable photo-charge and galvanostatic discharge behavior, achieving a rapid charge to 5.4 V within 30 s under 1-sun illumination, followed by a controlled discharge to 3.0 V over 36 min at a discharge current density of 0.1C. Lu et al. introduce a robust, stretchable epidermal sweat-sensing platform integrating an Ag 2 O-Zn battery and a low-power electrochromic display (Fig. 23i) [359]. This platform operates independently to directly display various electrolytes or metabolites concentrations, eliminating the need for external connections. The battery system was fabricated in a stacked configuration utilizing customized inks for the silver current collector, zinc anode, Ag 2 O cathode, and titanium dioxide (TiO 2 ) separator. The sequential layerby-layer construction ensured precise assembly and optimal performance, enabling the system to conduct sensing sessions over a week. The wearable patch features electrochemical sensors, ten individually addressable electrochromic pixels, and a microcontroller unit, all fabricated via screen printing. Furthermore, it maintained mechanical stability under 1,500 stretching cycles at 20 % strain and 10,000 on/off cycles. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 39 Recent advancements in implantable neural probes have enabled precise monitoring of brain activity by converting neural signals into electronic signals. Conventional tethered connections restrict movement of subjects, underscoring the need for wireless neural recording devices to observe natural behaviors. Very recently, Kwon et al. reported that a conformal quasi–solid-state ZIB seamlessly integrated the power source with the biological system, utilizing an aqueous quasi–solid-state electrolyte (Fig. 23j) [352]. For optimal integration, the Zn-ion microbattery (ZIMB) was 3D conformally printed directly onto a model of a mouse’s skull, produced via additive manufacturing. This approach resolves the mismatch challenge between flat batteries and curved surfaces, resulting in a streamlined battery system. Demonstrating superiority, the printed ZIMB proved significantly lighter than the pouch-type variant, with no discernible difference in active material mass loading (Fig. 23k). When implanted into a live animal for wireless neural recording, the preprinted skull model with ZIMBs exhibited promising results (Fig. 23l). 7.4.1.4.3. Performance-oriented applications. Novel 3D-shaped electrodes improve electrochemical performance across various applications, including lithium metal anodes and thick electrodes with complex structures. Various structural designs achieved via printing methods enhance efficient ion transport and stable high-mass loading, improving energy density. This achievement surpasses the performance of conventional slurry-cast electrodes. An electrically active lithium host was successfully demonstrated for Li-metal batteries based on a micro-patterned Si electrode (MPS) [360]. The MPS host is manufactured by applying micro-scale direct ink writing technology (Fig. 24a). The printed MPS host is engineered with designed electrical conductivity and a porous structure onto the lithiophilic conductive substrate (lc-substrate). The fabricated MPS host stands at a height of 21 µm and enables customization of pitch sizes (Fig. 24b). Here, a pitch of 150 µm was determined to be optimal, supported by the uniform deposition of Li within the pores (Fig. 24c). The MPS host is designed with a regular structure, featuring an areal capacity of 3.8 mAh cm 2 , high cell energy density (644 Wh kg cell -1 / 1538 Wh L cell -1 ), and stable cycling performance. Lim et al. developed a safe Li anode with high areal capacity and high-rate capability by employing a 3D-printed Cu framework (3DP-Cu) (Fig. 24d) [361]. The framework possessed high mechanical robustness, effectively restraining Li dendrite growth and volume expansion. Porous structure and a large specific surface area, which simultaneously suppressed Li dendrite growth. The Li@3DP-Cu cell demonstrates superior performance even with an increased areal capacity of 2.5 mA h cm −2 at a current density of 1 Fig. 24. Performance-oriented power sources. a) Schematic illustrating the structural and electrochemical characteristics of the printed MPS host. b) Cross-sectional SEM images of the MPS host consisting of the lithiophilic conductive (lc)-substrate (left) and the microgrid Si electrode active layer (right). c) Optical microscopy images and COMSOL simulation of the current density distribution of the MPS hosts (Pore size of 150 μ m). Reproduced from Ref. [360] with permission from The Royal Society of Chemistry, Copyright 2022. d) Fabrication and SEM image of a 3D Printed Cu framework (3DP-Cu). e) The symmetric cell profiles at a current density of 1.0 mA cm −2 and a capacity of 2.5 mAh cm −2 . Reproduced from Ref. [361] with permission from The Royal Society of Chemistry, Copyright 2020. f) A schematic depicting the additive manufacturing process of structured electrodes for 3D graphite thick electrodes. g) SEM images of the 3D graphite electrode. Reproduced from Ref. [362] with permission from American Chemical Society, Copyright 2022. h) Schematic depiction of 3D printed honeycomb electrodes utilizing high-loaded filaments. Reproduced from Ref. [363] with permission from Wiley-VCH GmbH, Copyright 2023. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 40 mA cm −2 . It maintains stable stripping/plating cycling with moderate charge/discharge profiles over extended periods compared to the compromised stabilities of Li@Cu and Li foil cells (Fig. 24e). This study provides an innovative approach employing 3D printing to fabricate copper-based framework for advanced Li metal battery systems. To achieve higher areal energy density with thicker electrodes, 3D printing is fascinating approach to enhance the electrochemical performances that exceed that of conventional one. Park et al. developed a method known as structured electrode additive manufacturing (SEAM) [362]. This approach enables the production of thick electrodes without the need for solvents or drying processes. This approach aligns anisotropic active materials, such as graphite flakes, along their longitudinal directions through highpressure induced shear flow. The multiscale porous structure through the thickness and oriented graphite flakes reduces lithium-ion path tortuosity, improving ion transport and providing more utilizing intercalation paths within the graphite flakes (Fig. 24f). A graphite anode fabricated with SEAM was densely stacked to a thickness of 2 mm, demonstrating no structural defects such as delamination or layer shifting (Fig. 24g). This precise alignment enhances areal and specific capacities at high current density, resulting in improvements of 260 % in specific and areal capacity at 1C when compared to slurry-cast electrodes. Fused deposition modeling has been introduced to enhance the areal capacity of printable electrodes [363]. This technique provides superior design flexibility and scalability compared to conventional 3D printing and post-processing techniques (Fig. 24h). The researchers utilized highly loaded filaments composed of 65 wt% of active materials, conductive additives, and thermoplastics such as polyethylene glycol diglycidyl ether and polylactic acid. Hence, the structural full cell achieved a capacity of 12.28 mAh cm −2 at a current density of 0.92 mA cm −2 . Moreover, the honeycomb-shaped electrode designs enhance area loading and promote uniform electrolyte distribution, resulting in more durable and structurally stable electrodes. 7.5. Conclusion and outlook In the past few years, printed batteries have attracted much attention owing to the ever-growing interest in portable/wearable electronics. We have briefly reviewed the recent developments and challenges of the printed batteries, with a focus on the printing techniques, ink materials/chemistry, and integration with devices of ink formulation, printing techniques, printable materials, and applications. Several notable progresses have been discussed in the printed batteries, surpassing the capabilities of conventional battery technologies. However, practical use and commercialization of printed batteries lie far behind those of conventional batteries. In this regard, the future development and practical prospects for the printed batteries can be summarized as follows: Enhancement of the electrochemical performances: Compared to the rapid growth of conventional batteries, especially Li-ion, driven by the expanded global market of electric vehicles and energy storage systems (ESS), printable batteries have not yet been widely commercialized. One of the significant reasons is their inferior electrochemical performances compared with their conventional batteries. For instance, in traditional sheet-type electrodes, mechanical calendaring process is conducted to ensure effective electrical conduction and increase of energy density reducing the voids in the electrodes. However, the direct integration of the printed batteries with various devices makes it difficult to exploit mechanical pressing. To address this performances issue, it is desirable to adapt highenergy–density electrochemical systems such as Li-S and Li-metal as an alternative approach. For the stable operation of these post-Liion systems, there are several hurdles have to be tackled including polysulfide shuttling, lithium dendrite growth and formation of dead-lithium. Defining the killer applications: Despite the performance of printed battery’s lagging behind the conventional one, the most compelling strength of the printed batteries lies in their monolithic integration with other devices. For instance, batteries required for implantable devices often cannot be manufactured using traditional battery manufacturing processes because their fixed form factor. Printed batteries utilizing tailored printing technology for specific applications present a highly attractive means to achieve this goal. Another significant advantage of printed batteries is their micro-fabrication ability. Conventional roll-to-roll manufacturing processes lack the precision required for fabrication of microbatteries (device footprint <1 cm 2 ) Furthermore, when the size of batteries shrank down, volumetric/gravimetric proportion of packaging substance within the battery increased exponentially [364]. In this regard, high-precision printing technologies are a very attractive way to fabricate the microbatteries, which also reduce the proportion of packaging materials through direct integrated with the target devices. Scale up and cost reduction: For commercialization and wide distribution of printed batteries, scaling up production and reducing unit costs are essential. Particularly, with the rapid increase in battery production driven by the widespread adoption of electric vehicles, battery manufacturing based on roll-to-roll processes has achieved significant enhancement of the production speed (e.g. commercial electrode manufacturing speed: 100 m min −1 ). However, the printing process, especially DIW printing method favorable for direct integration with device, exhibit lower throughput compared to roll-to-roll processes [285]. This low production rate consequently leads to increase of the battery cost. Therefore, scaling up and resulting decrease of the battery production cost can play a crucial role in practical application of commercialization of printed batteries. The printed batteries described here hold great promise as an energy storage platform that can bring us closer to a battery of things (BoT) era featuring human-oriented technologies. 8. Flexible batteries Flexible battery is a device that combines the considerable specific energy and the characteristics of being stretched, bended and twisted [365–369]. These characteristics are determinedly needed by the specific applications of powering wearable electronic devices, electronic skins, flexible displays and implantable medical equipment. In recent years, the development of powering devices towards diversification, flexibility, lightweight and thickness facilitates the rapidly evolution of flexible batteries [370–373], and C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 41 of the ‘anode-free’ LiPON based 2D microbattery from Cymbet [438] delivered 0.3 mWh cm −2 and peak discharge currents of 0.46 mA cm −2 for 20 ms. This was based on the fully packaged, surface mount technology (SMT) compatible, 8 ×8 mm footprint battery. The cells achieved 1,000 cycles to 50 % depth of discharge. To go beyond the capacities and peak current capabilities of these 2D micron scale active materials in thin-film format researchers looked to 3D or even 1D nanowires as higher capacity options per unit footprint. Some impressive results with non-planar micro and nanostructures [422,439–445] were reported, mostly for half-cells and efforts to integrate those as active materials in full cell microbatteries have been intensively pursued. Templates such as porous anodic alumina, with sub-micron diameter openings, have been used to form the 1D active materials and were even investigated to form an array of nanobatteries [446]. The alumina template was placed on a 400 nm SnO 2 thin-film anode material followed by infilling of the pores with 20 μ m polyethylene oxide (PEO) electrolyte and 40 μ m V 2 O 5 ambigel cathode and with which they achieved ~ 90 μ Wh cm −2 μ m −1 for the arrays. Another option to structure the battery materials [447] utilized high aspect ratio 3D etched structures, such as through holes in substrates or interposers, that connected the top and bottom surfaces and greatly increase the potential active surface area per unit footprint by up to 23 times. As in the previous case, this hybrid cell was not fully solid-state. The complex processing required that the substrate was activated and coated with a conductive electroless nickel barrier layer prior to molybdenum oxysulphide cathode electroplating. The electrolyte was poly(vinylidene difluoride) (PVDF) based polymer with conduction enhancers and the anode was carbon in bead format infiltrated into the structure with binder and solvent. Both of these layers were spin coated sequentially and vacuum processed to increase the coverage uniformity. Using a mid-discharge voltage of 1.7 V the energy achieved was 1.7 mWh cm −2 . The maximum discharge current investigated was 1 mA cm −2 . Deep reactive ion etching (DRIE) of silicon has also been utilized to increase the surface area per unit footprint [448,449]. The small feature sizes enabled by the DRIE necessitate ultrathin-film active materials deposition in the high aspect ratio structures with vertical sidewalls. Etch depths of 135 μ m can result in a surface area enhancement of 28 times for such substrates and an estimated 5 mWh cm −2 energy capacity. The difficulty with such structured substrate use, is the need to deposit successive, conformal, pinhole-free layers in even smaller features than previously envisioned to include, barrier layers, current collectors and the three active battery material layers. The timing of these efforts coincided with the commercial development of atomic layer deposition (ALD) precursors and equipment as a highly controlled and conformal method for materials deposition which is particularly well suited to oxide materials deposition, as required for most high energy battery cathodes. Electrodeposition has been utilized on a number of occasions to achieve the 3D structuring of active materials or substrates [422,444,445,450,451]. In cases where an interdigitated structure can be realized, electrodeposition is a viable technique to deposit nm to mm scale materials in high aspect ratio, for both anodes and cathodes. Three-dimensional bi-continuous interdigitated microelectrodes [452], based on plated nickel supports was achieved by electrodeposition through self-assembled polystyrene (PS) spheres at a substrate. This resulted in a porous nickel scaffold onto which the active materials could be plated, a nickel-tin alloy for the anode and manganese dioxide for the cathode. The maximum active material thickness investigated was nanoscale, 90 nm for the anode and 67 nm for the cathode. The PS spheres diameter, and IDE width and separation were varied to modify the density and output characteristics of the cells. When tested in perchlorate-based ethylene carbonate (EC) / dimethyl carbonate (DMC) organic solvent electrolyte at 1.5C rate the energy density was 0.225 mWh cm −2 , limited by the nanoscale thin-film active material. The highly conducting and structured support did enable a power density of mW cm −2 even up to very high C rates. A modification of this work to improve manufacturability and extend the cycle life used holographic lithography and SU8 photoresist processing to structure the porous substrate [453]. The active electrode material thickness was again limited to 100 nm and for 10 μ m thick electrode supports an energy density of 0.045 mWh cm −2 was achieved and 0.006 mWh cm −2 retained even at 1000C discharge rates. The cycle life was Fig. 29. a) Schematic of 3D printed and packaged microbattery. Reproduced from Ref. [290] with permission from Wiley, Copyright 2013. b) Interfacial nanoengineering by ALD coating of alumina on lithium cobalt oxide (LCO) and the resulting improved high rate capability by comparison with untreated bare LCO. Reproduced from Ref. [462] with permission from American Chemical Society, Copyright 2018. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 48 extended to 200 with a 12 % decrease in capacity at that point. A recent review has described the range of cathode materials that can electroplated to potentially go beyond the planar, conformal and low thickness levels of standard vacuum processed thin-films [454]. That work lists the wide variety of materials and processing media to achieve electrodeposition of cathodes such as LiCoO 2 from molten salts [455], MnO 2 [456], and V 2 O 5 [457], from aqueous solutions and LiFePO 4 from ionic liquids [458]. They also highlight the possibility of using lithium-free plated cathodes which when combined with a lithium metal anode eliminates the issues associated with high energy density anodes, such as, Si and Ge, that become embrittled and rapidly lose capacity on cycling. Lithium-free cathodes described include MoS 2 [447], FeS 2 [459], and V 2 O 5 [460]. 3D printing technology or additive manufacturing is another potential option to achieve 3D structured microbatteries. The technique can be utilized to deposit established battery materials or potentially provide novel energy storage solutions as described in a comprehensive review [461]. An example of 3D printing capabilities has been reported for microbattery cells consisting of Li 4 Ti 5 O 12 and LiFePO 4 as the anode and cathode, respectively [290] and shown in Fig. 29a). The printed electrodes were annealed at 600 ◦C in an inert gas to remove the organic additives and promote nanoparticle sintering. A poly(methyl methacrylate) (PMMA) preform was laser cut and placed around the microbattery before sealing with poly(dimethyl siloxane) (PDMS) gel cured at 150 ◦C. The assembly was then filled with liquid electrolyte and sealed with a small glass cover and PDMS. The equipment utilized had a minimum resolution of 1 μ m and was capable of printing interdigitated electrodes over 1 mm 2 to 1 m 2 in area. For the cells reported, the electrode width was 60 μ m processed using a 30 μ m diameter nozzle. In an eight-layer full cell tested with lithium perchlorate in EC/DMC solvent the energy density was 2.7 mWh cm −2 for the 30 cycles reported. As the printing technology and more printing inks become available it is likely that we will see further developments in this additive processing to achieve bespoke solutions for particular energy storage options, such as on flexible substrates. The use of LiPON as the solid-state electrolyte of choice for thin-film microbatteries was based on introducing a nitriding step into the use of lithium phosphate electrolytes which resulted in an electrolyte with increased ionic conductivity and cycling stability. First principles analysis shows that many of the solid-state electrolytes investigated to date are thermodynamically unstable with respect to both electrodes and it is the development of in situ formed protective films or deliberately deposited protective layers, and in some cases, the resulting improved kinetic effects which offers the possibility of their use [463–465]. An approach to develop appropriate interlayers has been the use of combinatorial high-throughput physical vapour deposition (PVD) techniques to provide a range of electrolyte/cathode interlayer materials [466]. In that work, compositions of a series of amorphous, as-deposited LiNbTa films were crystallised over a range of temperatures. The resulting film properties were examined for optimised conductivity and dielectric component, and fast charge transfer reactions at the interface in a 5 V class of all-solid-state lithium batteries. For the majority of the microbattery materials under investigation, interface nanoengineering is a viable option, as they are thinfilm and solid-state and potentially well-suited to ALD or chemical processing. In addition to improving interface compatibility, some unexpected benefits may arise, such as that shown in recent work which utilised ALD alumina on LiCoO 2 particles for analysis in standard organic solvent electrolyte [462]. The nanoscale alumina, shown in Fig. 29b), maintained the capacity of the cathode and significantly improve the reaction kinetics, it was postulated, by aluminium doping into the LiCoO 2 cathode material at the interface. They also argued that the protective film suppressed the high potential phase transition of the cathode and decreased any potential Co dissolution. Over 80 % of the discharge capacity was accessible at 20C discharge rates for samples subjected to a 3 nm alumina layer process by comparison with less than 15 % in the absence of the alumina at the same discharge rate. The differences in rate capability only became significant at those above 1C. Sputter deposited thin-films of LiCoO 2 also showed an improvement in output characteristics when subjected to an ALD alumina coating [467]. When tested in standard EC/diethyl carbonate (DEC) electrolyte the alumina coating permitted cycling to 4.4 V for the LiCoO 2 without loss of activity and enabled greater than 80 % of the capacity to be accessed at 2.7C. Even with this high potential limit for the cathode, 61 % of the capacity was accessed at cycle 500 for the high discharge rate. A similar benefit of interface engineering was shown recently for a plated V 2 O 5 cathode. In that case, 1 nm coatings with ALD alumina were sufficient to enhance the cycle life against a lithium metal anode and rate capabilities for the cathode when tested in organic solvent, ionic liquid or polymer gel ionic liquid-based electrolytes [467]. The polymer gel ionic liquid (PGIL) electrolyte was prepared by mixing the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (C4mpyrTFSI), LiTFSI and poly (vinylidene difluoride-co-hexafluoropropylene) (PVDF-HFP) [468]. The alumina coated V 2 O 5 retained 93.5 % capacity to cycle 800 for a 1C discharge rate with a lithium metal anode indicating the potential for ionic liquid gel electrolytes which have similar conductivities to standard organic solvents to be used rather than ceramic or glassy all-solid-state electrolytes for microbatteries. Although most research has been focused on the lithium-based microbatteries discussed so far, sodium microbatteries provide an alternative solution to the problem of microenergy storage with unique advantages and challenges. Often considered the bulky and inefficient analogue of lithium, sodium’s main benefits are its natural abundance and resulting low cost. In their latest 2023 report, the European Commission has recognized lithium as a critical raw material both in terms of its supply risk and also its economic importance [469]. While sodium cannot compete with lithium for high end energy storage performance, its cost effectiveness could render it an excellent alternative for particular applications [470]. The similarities between sodium and lithium and potential electrolyte/cathode materials means it is as close to a ‘drop-in replacement’ as possible in manufacturing technology requiring minimal processing equipment modifications [401]. Compatible materials include the use of layered oxides or phosphate analogues as cathodes [471]. For microbatteries sodium metal would be the anode of choice and its use may also require the use of solid-state or nearly solid electrolytes. Solid-state NASICON or b-alumina electrolytes have higher ionic conductivity than solid-state lithium electrolytes [470] and offer an opportunity for development of the microbattery format with higher power capabilities. As is the case for larger batteries, the thermodynamic stability of aluminium with respect to sodium at low potentials, means that it can be used as the low-cost current collector for both electrodes, further reducing cost C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 49 by replacing the more expensive copper required for lithium systems. Aluminium is also a material that has been used in microelectronics applications for many decades and significant expertise exists for its deposition and patterning. Sodium microbattery designs based on 1D, 2D, and 3D architectures have been reported [472,473]. The 1D architectures include coaxial, twisted and parallel electrode configurations [409,474]. However, 2D planar and 3D designs are more common, as observed for lithium systems. Although the number of articles on sodium-ion batteries is growing each year, much of the discussion is focused on large scale storage with relatively few focused on the development on full cell sodium microbatteries. The European Union project Nereid (Nanoelectronics Roadmap for Europe) [475] included a chapter dedicated to energy harvesting which included an analysis of microbattery energy storage. The assessment concluded that in the short term (to 2026) microbatteries will be deployed for internal use in factory environments and externally to power autonomous sensors. The first deployment in healthcare systems is envisaged in medical patches. In the longer term (to 2033) the roadmap suggests that they will be employed in the home, extensively in agriculture and in implantable devices for each of the three cases. In terms of areal energy density, it was suggested that the realized 5 mWh cm −2 would be achieved by 2023. Incremental increases to 6. 5, 8 and then 10 mWh cm −2 were foreseen for the years 2026, 2029 and 2033, respectively. It is anticipated that these improvements will occur due to new and optimized deposition techniques, multilayer processing and novel electrode and electrolyte materials combinations. 10.3. Applications Microbatteries have long been perceived as the option to power microdevices and the recent focus on ‘internet of things’ (IoT) devices and applications, facilitated by advances in communications technologies, is providing a large potential or target market for rechargeable microbatteries integrated with energy harvesting. There are cases where IoT devices do not require an energy storage option, such as for RFID chips or those which can be powered solely by harvested energy. However, a significant proportion of the IoT devices will require energy for operation beyond that provided by ambient harvesting sources or require energy when none is available for harvesting. Stored energy can also assist with optimization of device functionality and operation during periods of high energy requirements, such as, during sensing or external communication. As with many new technologies one of the first technology applications to explore the potential use of thin-film solid-state microbatteries was the space industry. Key drivers for that technology are decreased weight and appropriately sourced energy provision. On-chip integrated microbatteries can minimize unnecessary cabling by co-locating the microbatteries and electronic chips to provide point-of-use power, reduce device weight and packaging and match the energy requirements of the system with the capacity of the rechargeable battery. Some early work in this area showed the potential to pattern and size microbatteries as required, such as, by their connection in series (Fig. 28b) or parallel to match the microspacecraft applications and a specific example of a switch array microsystem [425,476]. In addition to the basic needs for the energy source, many space applications have requirements that are inherently aligned with thin-film microbatteries including the ability to operate safely without leakage over a wide temperature range. The robust all-solidstate microbatteries have also shown high reliability, very low self-discharge and long cycle-life which is a requirement for space applications or missions where the energy source cannot be easily replaced. Similar baseline characteristics apply to batteries for medical wearable or implantable devices. These two sectors are the least cost sensitive application domains for which the market may support more early adoption and costly fabrication and packaging options than those of more mainstream energy storage markets. A key requirement for their more general use is to match the available energy which can be harvested or supplied by short term wireless power transfer with the stored energy of the microbattery and minimization of the energy required by the microdevice for operation. This requires innovative circuit design and specifically developed ultra-low power management integrated circuit chips. Options to integrate miniaturized photovoltaic (PV) cells from 0.07 to 1 mm 2 have been described for use in intraocular pressure Fig. 30. A) 1.5 mm 3 size MEMS pressure sensor with PV cell, microbattery, antennae and integrated electronics. Reproduced from Ref. [477] with permission from IEEE, Copyright 2011. b) 8.75 mm 3 temperature sensor in three layers with PC cell, integrated circuits and thin-film microbattery. Reproduced from Ref. [478]. with permission from IEEE, Copyright 2013. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 50 sensors (1.5 mm 3 ) [477] and for a wireless temperature sensor [478]. In both cases the electronics and energy harvester were integrated in microsystems with Cymbet supplied microbatteries. In the first case the microbattery was custom made with 1 μ Ah capacity. This was fabricated for the miniature device application limited by the acceptable incision dimensions for the device implant, the curvature of the cornea and dilation of the pupil. The electronic circuits included a wireless transceiver, capacitance to digital converter (CDC), a DC-DC switched capacitor network (SCN), microcontroller, and the memory was fabricated in 0.18 μ m complementary metal oxide semiconductor (CMOS) as shown in Fig. 30a). The custom made microbattery demonstrates a significant advantage of these thin-film microbatteries which can be varied in footprint simply by changing the mask designs for the thin-film deposition. They can be fabricated in irregular or elongated shapes to match scenarios that require specific dimensions such as a narrow but long battery maintaining the stored energy density. This may be true of many medical device applications, particularly implantables for future sensors. In the case of the 200 nW temperature sensor they developed a larger 8.75 mm 3 microsystem using 1 mm 2 PV energy harvesting cells, a 12 μ Ah thin-film microbattery from Cymbet and ultra-low-power circuits integrating an ARM Cortex-M3 microcontroller Fig. 30b). The microsystem consumed 7.7 W in active mode and 550 pW in standby mode between measurements. The microsystem was capable of processing temperature data hourly for 5 years using only the initial energy stored in the battery or had indefinite lifetime using the energy harvesting of the PV cells to recharge the battery for long-life autonomous operation. To increase the energy density for implantable devices where size can be critically constrained one option is to increase the thickness of the electrodes [479]. Using a 20 μ m sputter deposited LiCoO 2 cathode the authors achieved an energy density of ~ 3.3 mWh cm −2 at device level. In this cell they utilized a 3 μ m LiPON electrolyte and a ‘lithium-free’ anode. The 3.1 ×1.7 mm 2 thin-film microbatteries which were 95 μ m in total thickness had a discharge capacity of 25 μ Ah and were capable of maintaining 60 % of this value at 0.25 mA or 10C discharge rate. This flexibility of design again illustrates the potential for thin-film microbatteries for medtech applications. A further, more recent development in solid state microbattery fabrication for commercial applications that maintains the areal dimensions has been the demonstration of stacked cells that go beyond the placement of cells in a pyramidal format one over the other to increase capacity [480]. Ilika in the UK [481] extended their portfolio by developing processes to stack the Stereax M50 or 50 μ Ah capacity cell which has a 5.5 ×3.5 mm footprint and a normalised energy density of 0.9 mWh cm −2 . The six cell stack of the Stereax M300 product can deliver 5.45 mWh cm −2 in a package which is still under 1 mm in height. This is potentially a key development as models of solid state and/or 3D microbatteries which consist of poor electronic conducting active materials and low ionic conductivity in the electrolyte have shown that they will have non-uniformity issues except at very low current drain or C-rates [436,482–484]. Most of the applications envisaged for microbatteries require the periodic delivery of high currents during sensing operations or data transmission. This multilayer option is directed towards applications in the medical device or implant sectors. An alternative to the vacuum deposited solid-state batteries discussed so far is the recently introduced multilayered fabricated batteries using techniques similar to multilayer co-fired ceramic capacitor fabrication for surface mount component assemblies. The Fig. 31. Powering the IoT ecosystem including scientific disciplines, enabling technologies, IoT applications and stakeholders. Adapted from Ref. [487] with permission from IEEE, Copyright 2019. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 51 initial product developed by TDK [485] is a multilayer packaged battery in a standard 1812 format (4.5 mm ×3.2 mm ×1.1 mm) which has a capacity of 100 µAh at a rated voltage of 1.5 V giving an areal energy density of ~ 1 mWh cm −2 . It is solid-state, ceramic based, and therefore compatible with solder reflow typical of surface mount devices and initially targeted at the IoT application space. It is less energy dense with a lower rated voltage and, therefore, likely to service the higher volume and more cost sensitive IoT markets in conjunction with energy harvesting technologies. Providing energetic autonomy to electronic devices for remote monitoring is seen as a large potential market for sensor networks and IoT devices: •Where a simple primary battery is not sufficient •If using power cables significantly increases the cost or complexity (i.e., avionics, or space applications) •If devices are so numerous that changing batteries increases the maintenance cost and the logistics become unmanageable •In harsh environments where electronic devices cannot be accessed easily In these cases, remote monitoring can eliminate breakdowns and productivity losses by identifying failure modes or condition monitoring to increase lifetime or tracking of assets. The integration of energy storage with developing energy harvesting technologies also has the potential benefit of improving the sustainability of the energy solution. Less primary batteries would be required and disposed of at the end of their short lifetime. There is also a significant focus on the use of more sustainable or plentiful materials that are safe and readily recyclable to support a circular economy. An international workshop (https://www.enerharv.com) dedicated to the development and promotion of the energy harvesting, storage and micropower management circuits was established in 2018 and the third biennial event took place in June 2024 in Perugia, Italy. The community and related workshops are dedicated to ‘Powering the IoT’ ecosystem [486,487], with the various contributors outlined in Fig. 31. The ecosystem consists of stakeholders to assist with integration of these fields of research for new materials, devices and systems with developers for applications, and end-users and to accelerate the roll-out of IoT devices. The goal is to create awareness and foster collaborations that will result in demonstrators/products aligned with technology roadmaps, and provide options to realize the development of standardized, interoperable and system-optimized IoT solutions. 10.4. Conclusions and future challenges Microbatteries for energy storage, particularly for IoT applications or integrated in electronic devices, have areal energy densities of ~ 5 mWh cm −2 when used with µm scale lithium-based thin-film materials. They can be cycled thousands of times with little capacity fade, particularly when the depth of discharge is minimized. Solid-state materials offer advantages in terms of safety, cycle life and energy per electrode thickness. Based of the early research on solid-state lithium microbatteries including lithium metal-based cells, research is now being extended for their potential use in larger cell formats appropriate to EV applications. This increased interest in solid-state electrolytes, interface improvement and novel analysis including operando studies [488] and potentially microelectrodes for undistorted and high-rate analysis [489–491] will assist with developments at all scales and all materials combinations for energy storage applications. A particular area of interest is in the electrolytes given that the ionic conductivity of the all-solid-state options is still significantly lower than the more common liquid-based electrolytes of current commercial lithium-ion batteries. Solidstate electrolytes offer enhanced safety by eliminating organic solvents of typical lithium-ion batteries and optimized charge times with thinner active electrode and electrolyte materials. The analysis above has described how, despite efforts to 1D or 3D structure microbatteries, 2D stacking of individual microbattery unit cells is most likely the preferred realistic option to increase the energy and power density in the same footprint while maintaining the advantages of the thin-film format. Laminated ceramic components under development for multilayer stacked microbatteries are just now entering the market and may play a significant role in solderable surface mount devices for integrated electronics and IoT applications. With higher energy density materials, their use may be extended to other larger scale applications. Significant efforts are underway to utilize more sustainable, safe and lower cost materials as the active battery components, or in particular cases, even using biodegradable materials and substrates for batteries in distributed sensors. In the latter case, with less energy dense materials, larger cell formats may be required. As with lithium-ion chemistries it is desirable to exclude cobalt in the cathode and ultimately move towards the more abundant sodium-based analogues of the benchmark lithium systems. Alternative electrolyte materials tending towards near solid-state are of interest with optimization of polymer, ceramic or gel-based electrolytes. Those were intensively investigated in the early days of lithium-ion development but can now include the developing field of ionic liquids or their polymer gel analogues. The desire is to include the benefits of the nearly solid-state materials while maintaining the ionic conductivity at current lithium-ion solvent system levels. Interface nanoengineering which is also now possible through a variety of processing options, including ALD, is also a developing field of research to minimize unwanted interfacial reactions while permitting low interfacial contact resistance with novel electrolytes and therefore, enhanced kinetics with extended cycle life. Microbatteries can assist with the enhanced performance of distributed sensors. Ongoing research is required to integrate appropriately sized storage elements with energy harvesting options and power management systems to optimize the offering for the anticipated billions of sensor devices in the predicted future IoT scenario. An even more integrated option for future devices could be the use of photobatteries or those in which active battery materials can be recharged directly. Recent analysis of such materials in a dedicated test cell demonstrated that photo-charging is feasible when the conduction band quasi-Fermi level is positioned above the anode intercalation/plating potential [492]. Simulations and models describing microbattery characteristics have provided guidance for the architectures and fabrication of the devices. These will require updates to assist with design and optimization of the new specific C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 52 active architectures, dimensions, electrode materials, interfaces and electrolytes. 11. Smart capabilities for the different battery systems Smart materials are revolutionizing lithium batteries by enhancing efficiency, durability, and adaptability while paving the way for sustainable, flexible, and shape-adjustable battery designs [493]. These innovations include self-healing polymers, shape-memory alloys [494], and adaptive nanostructures [495], which significantly improve performance and lifespan as represented in Fig. 32. For instance, self-healing materials allow to repair micro-cracks that develop during charging cycles, reducing capacity loss and extending operational life [496,497]. Smart coatings and separators adapt to environmental changes, such as overheating, by altering their properties to prevent thermal runaway [498]. Flame-retardant materials, such as phosphate-based compounds [499] and ceramic-coated separators [500], suppress combustion and enhance safety. Advanced electrolyte additives and modified cathode or anode coatings further boost safety by reducing flammability and mitigating lithium dendrite growth, all while maintaining high energy density and performance. In critical scenarios, built-in safety mechanisms ensure secure operation [501]; for example, separator membranes can melt at extreme temperatures to block ion flow [502], or built-in circuits can disconnect power if voltage, current, or temperature exceeds safe thresholds [503]. These innovations make lithium batteries more reliable, versatile, and suitable for demanding applications like electric vehicles and renewable energy storage. Self-sensing to enhance life and safety through status monitoring and prediction is another capability of next-generation batteries. The Fiber Optic Bragg Grating (FBG), Distributed Fiber Optic Sensors (DFOS) sensors and a thin-film resistance temperature detectors allows to assess temperature, strength, and displacement at the cell level [504,505]. 12. Circular economy and recycling issues 12.1. Introduction The environmental problems that contemporary society faces, have become prevalent and important social concerns. These problems, especially those related to air quality and climate change, are mostly caused by the economy’s heavy reliance on fossil fuels. As the transition from a fossil fuel powered society to a society strongly relying on renewable energy requires an increasing use of energy storage systems, the reuse and recycling of those systems also becomes a critical issue, since it promotes the idea of a circular economy, reduces the need to extract additional resources and strongly contributes to the reduction of the associated environmental impact. In fact, the drive to achieve a net zero emission by 2050 has brought about a surge in the utilization of energy from renewable sources. Due to the intermittent nature of the predominant renewable energy sources such as solar and wind, energy storage systems has become an integral part of the solution to emission reduction of greenhouse gases (GHG) [506]. Rechargeable batteries, also known as secondary batteries, are currently the dominant energy storage systems. The installed capacity of energy storage batteries in the world increased from 9.6 GW h in 2020 to 50.8 GW h in 2022 and is projected to reach 288.3 GW h by 2025. This represents a Fig. 32. Smart capabilities for the next generation of battery systems. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 53 compound annual growth rate of more than 100 % from 2020 to 2025 [507]. There are a variety of secondary batteries in the market, ranging from the very common and traditional lead-acid batteries, to nickel–metal hydride battery (NiMH) and Lithium-ion polymer batteries (LiPo). However, since its commercialization in the early 1990 s, lithium-ion battery technology (LIB) has dominated the secondary battery market due to their high energy and power densities, as well as their cycle stability [508]. The large-scale production of electric vehicles (EV) has further accelerated the growth of the LIB industry. The global production capacity of LIBs has increased from 25.6 GWh in 2009 to 218 GWh in 2019 and predicted to be more than 2500 GWh in 2030 [509]. With a life span of 3 – 8 years for LIBs used on mobile devices and 10 – 15 years for the EV power battery packs, the quantity of LIBs reaching their end of life (EoL) has also been increasing over the years. The spent LIB capacity is expected to reach 300 GWh by 2030, as shown in Fig. 33 [510–512]. Regardless of their chemistries, all secondary batteries contain transition metals such as cobalt (Co), nickel (Ni), manganese (Mn), iron (Fe) and lead (Pb). A direct consequence of the sharp increase in the production of secondary batteries is the huge demand on transition metals. In the conventional linear economy (LE) where manufacturing industry takes the form of take-make-waste/discard, such a growth cannot be sustained with the finite natural resources on planet Earth [513]. Furthermore, concentration of some transition metal reserves only in a limited number of countries, particularly those for cobalt and nickel, makes their supply vulnerable. Many economically developed regions have classified them as critical materials [514]. It’s long been recognized that the significant quantity of transition metals in the spent LIBs is valuable secondary resources for their future manufacturing. This, coupled with the fact that the electrolyte in the spent LIBs is a potent contaminant to the environment if directly discarded, necessitates recycling of spent LIBs [509,515]. Reviews on LIB recycling are extensive; notable ones include Yang et al.[61] and Li et al.[516]. Most of the reviews focus on the technologies and their progresses for the materials recovery from the spent LIBs [510]. This review will, using LIB as a case study, take a holistic approach to assess the development of secondary battery industry as a whole from a sustainability and circular economy (CE) perspective. The review will start with a brief summary of the currently used recycling and materials recovery technologies. The emphasis is on the new technology developments, particularly the use of deep eutectic solvents (DESs) in the extraction of metals that has started to attract serious research attention only in recent years. It will then outline some major issues and challenges currently faced in battery recycling. The review will discuss how the CE and sustainability principles can be applied to the design of battery cells and systems before concluding with recommendations. 12.2. Recycling and material recovery technologies Recycling of spent batteries starts with battery collection and transportation to sorting and preliminary processing stations or centers. These steps are important to the overall recycling process and will be discussed briefly in other sections in the context of the efficiencies and economics of the whole recycling process. This section will only discuss the development of technologies for the Fig. 33. Quantity of spent LIBs and its projection to 2030. Reproduced from Ref. [512] with permission from American Association for the Advancement of Science, Copyright 2021. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 54 recovery of materials from the recycled spent LIBs. The technologies that have been used for the recovery of materials from the spent LIBs can be broadly classified into three categories, namely, direct recycling, pyrometallurgy and hydrometallurgy. Fig. 34 shows the process steps each of the technologies goes through. Except the pyrometallurgical method, both direct recycling and hydrometallurgical method require pre-processing the recycled spent LIBs to obtain the active electrode materials, termed the ‘black mass’ in industry, as the feed material. The pre-processing steps include discharging, dismantling, crushing, sieving, and physical separation [517–520]. Discharging removes the residual energy from the spent batteries to avoid short circuit current of the charged electrodes during the dismantling step, which could cause explosive reactions due to the presence of flammable electrolyte [521]. Discharging of a battery pack or a module from an EV is often achieved by connecting it to an external load which can harvest energy from the batteries. For individual battery cells, or sometimes the small-sized modules, discharging is done by submerging the batteries in electrolyte solutions such as sodium chloride (NaCl), sodium carbonate (Na 2 CO 3 ), manganese sulphate (MnSO 4 ), sodium sulphate (Na 2 SO 4 ), ferrous (II) sulphate (FeSO 4 ) [522]. The batteries are then crushed into pieces up to millimetres in size [519]. The crushed materials are separated using different separation methods including sieving, magnetic, eddy current, electrostatic, gravity separation, and froth flotation [522] to obtain the final product of the pre-processing, namely, the black mass. 12.2.1. Direct recycling One of the main degradation mechanisms for LIBs is the loss of lithium ions from the cathode. This is caused by the repeated charging-discharging cycles that eventually lead to changes in the crystal structure that can no longer accommodate the chemical reinsertion of the lithium ion back into the cathode materials [514]. Direct recycling is essential to relithiate the cathode material to restore the LIB functionality. Various techniques have been employed in the direct regeneration of spent cathode materials including chemical relithiation [523], hydrothermal relithiation [524], solid-state sintering [525], electrochemical relithiation [526], molten salt relithiation [527], and ionothermal relithiation [528]. These methods involve exposing the spent cathode material to an environment rich in lithium and utilizing both physical and chemical processes to reintegrate lithium ion into the crystal structure of the cathode material. Further, the lithium loss, due to a capacity loss of the LIBs, denotes that a proportion of the transition metals in the cathode material are permanently in the higher valence state. Consequently, the regeneration process also necessitates the reduction of this portion of the transition metals back to their lower valence state [529]. Chemical relithiation and hydrothermal relithiation, along with solid-state sintering, operate at lower temperatures in lithium-rich solutions with the assistance of a reductant, whereas hydrothermal relithiation requires a high pressure [523,524]. Solid-state sintering mimics the cathode material production process by embedding lithium ions back into the crystal structure of the cathode material under high-temperature conditions, resulting in high crystallinity and ideal stoichiometry [525]. Electrochemical regeneration, recognized as a sustainable and environmentally friendly technology, drives lithium ions back into cathode materials through electrochemical means for direct regeneration. Ionic liquids with good thermal stability can serve as effective reaction or flux media for cathode material regeneration under mild conditions [528]. A eutectic salt mixture has also been used as a medium to provide a lithium source for cathode relithiation. When heated to a sufficiently high temperature, the molten salt facilitates enhanced lithiumFig. 34. Process steps of typical materials recovery technologies. Reproduced from Ref. [514] with permission from Elsevier, Copyright 2024. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 55 ion diffusion, thereby aiding in the regeneration of cathode materials [527]. The residual lithium source left after the cathode regeneration reaction is easily soluble and recoverable for future use. 12.2.2. Pyrometallurgical processes Pyrometallurgy is a traditional process to recover metals from the spent battery wastes using high temperature processes such as incineration, smelting, drossing, sintering, and melting [530,531]. Heat treatment in air is typically conducted in incinerators, blast furnace, or plasma arc furnace, where the volatile matter and other organic constituents (e.g. plastics) are removed as gases [530]. Heat treatment under reducing conditions results in the formation of pure metals, metal alloys and metals containing slag [519]. To recover and selectively separate the metals, pyrometallurgical process is often followed by hydrometallurgical and electrochemical processes. The pyrometallurgical process for LIB recycling has been industrialized by Umicore where the spent batteries are incinerated to produce a metal alloy, which are then fed into a hydrometallurgical process to recover 95 % of the cobalt, copper and nickel [532]. The biggest advantage of pyrometallurgical approach for the recovery of materials from the spent LIBs is its ability to treat the batteries without the delicate dismantling and battery crushing processes described before. However, due to the inherent high temperature nature of this approach, it consumes a significant amount of energy, which translates to a high carbon footprint. This method also releases toxic gases (e.g. dioxins) and a process waste stream [519,533]. Several modifications (e.g. metal extraction with vacuum, ultrasonic assisted pyrometallurgical metal recovery, addition of ammoniation in the pyrolysis step) have been proposed to improve the conventional pyrometallurgical process to reduce waste emission and increase recovery efficiency [526,530]. 12.2.3. Hydrometallurgical processes Hydrometallurgical processes involve dissolution of metals/metal oxides from the black mass using a leaching agent, which is the most critical process step that determines the overall efficiency of this approach. The agents can broadly be categorized into three groups, namely, inorganic acids, organic acids and DESs. Fig. 35 compares the various advantages and disadvantages of the leaching agents used for materials recovery from spent LIBs. From the figure, DESs are seen to be the best owing to their higher biocompatibility and biodegradability, improved dissolution kinetics and lower costs of their synthesis compared to the traditional inorganic and organic acids [534–538]. To date, however, only strong inorganic acids are used at industrial scale. For example, Umicore Val´ eas (Bruxelles, Belgium) used sulphuric acid (H 2 SO 4 ) to leach the alloy from its pyrometallurgical process to recover primarily Co and Ni from spent LIBs [532]. The use of organic acids and DESs, together with bio-based leaching agents, is still at the lab scale research stage and the use of salt as a leaching agent depicted in Fig. 35 is in fact uncommon. Details on the use of strong inorganic acids (e.g. H 2 SO 4 , HCl, HNO 3 , aqua regia), organic acids (e.g. malonic, tartaric, oxalic citric, salicylic glycolic, succinic, lactic acid etc.) and alkalis (e.g. NaOH, NH 3 ) for the extraction of metals from the recycled spent LIBs are available in extensive reviews by Pradhan et al. [536] and P. Li et al. [516]. Interested readers are referred to those papers for further information. Further, P. Li, et al. [516], Zhao et al. [510] and Millian et al. [514] provided detailed summaries on bioleaching while Yu et al. [539] presented a comprehensive review on process intensification for the hydrometallurgical processes. This section will only provide a brief review on the leaching of black mass from the recycled LIBs using a DES, which has emerged as very promising and attracted significant research interests in recent years. A DES is a mixture that contains a hydrogen bond acceptor and a hydrogen bond donor [534]. The ability of a DES to extract metals from the ores and electronic wastes was reported in the mid-2000 but application of DES to extract metals from the black mass from spent LIBs was not studied intensively until 2019 [534]. Although DES leaching of metals does not strictly belong to hydrometallurgy as DESs do not naturally contain water, it is often classified as hydrometallurgy due to its extraction of metals in a liquid state at a relatively low temperature. Depending on the hydrogen bond donor and acceptor used, various DESs with different physicochemical properties can be prepared. The ability of a DES to leach metals depends on its reducibility and acidity, whereas the kinetics of the leaching process depends Fig. 35. Spider chart of hydrometallurgical recycling from different solutions. Reproduced from Ref. [529] with permission from Elsevier, Copyright 2021. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 56 on its viscosity [534]. The reducibility of the DES is determined by its Fukui function, which can be calculated with DFT, and ionization potential [540,541]. A low ionization potential would indicate a strong reducing DES, which is beneficial to the recovery of transition metals [541]. The acidity of a DES is governed by the hydrogen bond donor used. Generally, higher acidity DESs are reported to be better in dissolving most of the metal oxides. Most studies on DESs have used choline chloride or betaine as the hydrogen bond acceptor to pair with various hydrogen bond donors such as thiourea, glucose, fructose, xylose, citric acid, tartaric acid, malonic acid, glycerol, oxalic acid [529]. The viscosity of most of the DES was found to be >100 cP at ambient temperature [542]. This is high and limits mass transfer processes, resulting in low leaching kinetics. It can be reduced by 10–30 times through addition of water [543]. However, the amount of water added has to be limited as it significantly affects the hydrogen bonding in the DES, which in turn affects the leaching kinetics and dissolution processes [543]. Compared with those on hydrophilic DESs, investigations on the utilization of hydrophobic DESs, which usually have a low polarity, high viscosity and lower ionic conductivity, are limited [544,545]. Osch et al [546] showed the possibility to selectively remove transition metals from water using decanoic acid and lidocaine. Since then, several more hydrophobic DESs have been developed and used to extract In and Au. However, no application of hydrophobic DESs to the recycling of batteries has been reported, which could be a fruitful research direction to pursue [547,548]. In addition to tuning the properties of the DESs, researchers have also attempted other means to improve the DES leaching efficiency. For example, Chen et al (2021) [549] showed that Co, Li and Mn could be recovered together in a two-step process where formic acid was first used to selectively extract Li, followed by DES extraction of Co and Mn before the final separation step using Na 2 CO 3 as the precipitation reagent. Peeters et al [550] showed that the addition of Al or Cu could reduce Co(III) in the black mass to Co(II), thus improving the leaching efficiency. Application of UV light to DES leaching was shown to affect the leaching efficiency which can be attributed to the absorption of UV light of Choline compounds [551]. Exposure of DES leaching to microwave irradiation was also shown to improve leaching kinetics [552]. However, due to its high energy density, microwave could cause DES to decompose. As this would affect the reusability of DES, the mechanism by which the leaching kinetics is improved needs to be carefully assessed. To recover the leached metal ions from DES, precipitation is the preferred method. The addition of oxalic acid to the DES after leaching results in precipitation of the transition metals of Co, Ni and Mn in the LIBs in the form of their respective oxalates, which is further oxidized to produce their oxides [553–555]. Other reagents such as NaOH and Na 2 CO 3 have also been used to precipitate the different metal oxides [534,540,556,557]. In contrast, little has been investigated of metal/metal oxide recovery from DES using electrodeposition wherein mainly metals and their alloys could be recovered [558,559]. Although studies have shown that DESs are an excellent media to leach various metal ions from the black mass, issues related to recovery, reuse of DES in the process remain a challenge. For electrochemical recovery, due to the limited electrochemical potential window, not all the metal ions can be electrodeposited [534]. The precipitation technique usually leads to a change in the hydrogen bonding and therefore the performance of DES deteriorates in its reuse. The maximum number of reuses of an oxalic acid-based DES was shown to be 15 [555]. For other DESs, it would be even lower. Therefore, a combination of precipitation, electrochemical recovery and solvent extraction might be required to improve the recovery of metals/metal oxides from DES while minimizing changes to the DES to allow its reuse for further leaching. 12.2.4. Comparison of industrial recycling processes Industrial scale recycling efficiencies of companies using the three materials recovery technologies discussed before are shown in Table 3. These are much lower than the reported lab-scale leaching efficiencies where near 100 % of the metals in the black mass have been reported to be extracted into the solution. This is expected as the recycling efficiency of a whole multi-step process would always be lower than the efficiency of any single step process and, in the case of an industrial scale recycling efficiency, the effect of scaling-up also comes into play. Nevertheless, it is evident that, from both the data shown in Table 3 and literature results from lab scale research, the efficiency of hydrometallurgy is the highest while that of pyrometallurgy is the lowest. A spider chart comparison of the three technologies on other performance measures such as cost, requirement on pre-treatment, process maturity/reliability, and waste generation is shown in Fig. 36a) [539]. Considering process maturity and requirements on pre-treatment, pyrometallurgical process is favourable. From the perspective of waste generation and the recovery rates of critical materials, direct recycling is better. Taking all performance measures into consideration as a whole, as well as process profitability that is now included in the chart, however, hydrometallurgy is the best. Many studies confirmed that producing LIBs from recycled materials is environmentally less intensive than producing them from virgin materials/ores, despite that recycling processes themselves generate net emissions [511]. One example of such studies on emission from recycling processes is shown in Fig. 36b). It can be seen that CO 2 equivalent emissions from the recycling processes Table 3 Industrial recycling processes in Europe and their recycling efficiency. Name Group Recycling efficiency Reference Akkuser Oy Direct physical full process 50–90 % [535,560] Duesenfeld GmbH Direct physical full process 72 % [561] Umicore Pyro-metallurgical refinement 50–61 % [562] Duesenfeld GmbH Hydro-metallurgical full process 91 % [563] C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 57 by the Ministry of Science and ICT (RS-2024-00344021). The authors thank BBSRC (BB/X011445/1) for financial support. Cheng Yan appreciate the financial support from two ARC Discovery Projects (DP250102887 and DP250102885). The authors also acknowledge support from the Science Foundation Ireland (SFI)/Research Ireland (RI) Connect Research Centre project co-funded by the European Regional Development Fund under Grant Number 13/RC/2077_P2, and the Sustainable Energy Authority of Ireland (SEAI) BatterySense project under Grant Number RDD 864. Data availability Data will be made available on request. References [1] Holechek JL, Geli HME, Sawalhah MN, Valdez R. A Global Assessment: Can Renewable Energy Replace Fossil Fuels by 2050? Sustainability 2022;14(8):4792. [2] Abbasi T, Abbasi SA. Decarbonization of fossil fuels as a strategy to control global warming. Renew Sustain Energy Rev 2011;15(4):1828–34. [3] Al-Ghussain L. Global warming: review on driving forces and mitigation. Environ Prog Sustain Energy 2019;38(1):13–21. [4] Zhang L, Jia C, Bai F, Wang W, An S, Zhao K, et al. A comprehensive review of the promising clean energy carrier: Hydrogen production, transportation, storage, and utilization (HPTSU) technologies. Fuel 2024;355:129455. [5] I.B. Boa Morte, O.d.Q.F. Araújo, C.R.V. Morgado, J.L. de Medeiros, Electrification and decarbonization: a critical review of interconnected sectors, policies, and sustainable development goals, Energy Storage and Saving 2(4) (2023) 615-630. [6] Hassan Q, Algburi S, Sameen AZ, Salman HM, Jaszczur M. A review of hybrid renewable energy systems: Solar and wind-powered solutions: Challenges, opportunities, and policy implications. Results Eng 2023;20:101621. [7] Sayed ET, Olabi AG, Alami AH, Radwan A, Mdallal A, Rezk A, et al. Renewable Energy and Energy Storage Systems. Energies 2023;16(3):1415. [8] El Haj Assad M, Khosravi A, Malekan M, Rosen MA, Nazari MA. Chapter 14 - Energy storage. In: Assad MEH, Rosen MA, editors. Design and Performance Optimization of Renewable Energy Systems. Academic Press; 2021. p. 205–19. [9] Yoo HD, Markevich E, Salitra G, Sharon D, Aurbach D. On the challenge of developing advanced technologies for electrochemical energy storage and conversion. Mater Today 2014;17(3):110–21. [10] De Carne G, Maroufi SM, Beiranvand H, De Angelis V, D’Arco S, Gevorgian V, et al. The role of energy storage systems for a secure energy supply: A comprehensive review of system needs and technology solutions. Electr Pow Syst Res 2024;236:110963. [11] Amir M, Deshmukh RG, Khalid HM, Said Z, Raza A, Muyeen SM, et al. Energy storage technologies: An integrated survey of developments, global economical/ environmental effects, optimal scheduling model, and sustainable adaption policies. J Storage Mater 2023;72:108694. [12] Noori A, El-Kady MF, Rahmanifar MS, Kaner RB, Mousavi MF. Towards establishing standard performance metrics for batteries, supercapacitors and beyond. Chem Soc Rev 2019;48(5):1272–341. [13] Yang F, Song X, Dong G, Tsui K-L. A coulombic efficiency-based model for prognostics and health estimation of lithium-ion batteries. Energy 2019;171: 1173–82. [14] Ramasubramanian B, Ling J, Jose R, Ramakrishna S. Ten major challenges for sustainable lithium-ion batteries. Cell Rep Phys Sci 2024;5(6). [15] Finkelstein SH, Ricci M, B¨ otticher T, Schmidt-Rohr K. How lithium-ion batteries work conceptually: thermodynamics of Li bonding in idealized electrodes. PCCP 2024;26(36):24157–71. [16] Meng J, Guo H, Niu C, Zhao Y, Xu L, Li Q, et al. Advances in Structure and Property Optimizations of Battery Electrode Materials. Joule 2017;1(3):522–47. [17] Heard DM, Lennox AJJ. Electrode Materials in Modern Organic Electrochemistry. Angew Chem Int Ed 2020;59(43):18866–84. [18] Fleischmann J, Hanicke M, Horetsky E, Ibrahim D, Jautelat S, Linder M, et al. Battery 2030: Resilient, sustainable, and circular. McKinsey & Company 2023: 2–18. [19] Njema GG, Ouma RBO, Kibet JK. A Review on the Recent Advances in Battery Development and Energy Storage Technologies. Journal of Renewable Energy 2024;2024(1):2329261. [20] Lehtim¨ aki H, Karhu M, Kotilainen JM, Sairinen R, Jokilaakso A, Lassi U, et al. Sustainability of the use of critical raw materials in electric vehicle batteries: A transdisciplinary review. Environ Challenges 2024;16:100966. [21] Chen Y, Kang Y, Zhao Y, Wang L, Liu J, Li Y, et al. A review of lithium-ion battery safety concerns: The issues, strategies, and testing standards. Journal of Energy Chemistry 2021;59:83–99. [22] Machín A, Morant C, M´ arquez F. Advancements and Challenges in Solid-State Battery Technology: An In-Depth Review of Solid Electrolytes and Anode Innovations. Batteries 2024;10(1):29. [23] Mottaghi M, Pearce JM. A Review of 3D Printing Batteries. Batteries 2024;10(3):110. [24] Costa CM, Gonçalves R, Lanceros-M´ endez S. Recent advances and future challenges in printed batteries. Energy Storage Mater 2020;28:216–34. [25] Barbosa JC, Fidalgo-Marijuan A, Dias JC, Gonçalves R, Salado M, Costa CM, et al. Molecular design of functional polymers for organic radical batteries. Energy Storage Mater 2023;60:102841. [26] Jin T, Singer G, Liang K, Yang Y. Structural batteries: Advances, challenges and perspectives. Mater Today 2023;62:151–67. [27] Ghasemi Yeklangi A, Ghafari A, Asgari Sima F, Akbari S. Advancing lithium-ion battery manufacturing: novel technologies and emerging trends. J Appl Electrochem 2024;54(12):2653–82. [28] IEA, Global EV Outlook 2024, IEA, Paris https://www.iea.org/reports/global-ev-outlook-2024, Licence: CC BY 4.0, 2024. [29] Li J, Fleetwood J, Hawley WB, Kays W. From Materials to Cell: State-of-the-Art and Prospective Technologies for Lithium-Ion Battery Electrode Processing. Chem Rev 2022;122(1):903–56. [30] Toki GFI, Hossain MK, Rehman WU, Manj RZA, Wang L, Yang J. Recent progress and challenges in silicon-based anode materials for lithium-ion batteries. Ind Chem Mater 2024;2(2):226–69. [31] Kim T. The origin of the aggressive degradation of Ni-rich transition metal oxide cathodes for high-energy density lithium-ion batteries. J Solid State Chem 2022;310:123040. [32] Tagawa K, Brodd RJ. Production Processes for Fabrication of Lithium-Ion Batteries. In: Yoshio M, Brodd RJ, Kozawa A, editors. Lithium-Ion Batteries: Science and Technologies. New York, New York, NY: Springer; 2009. p. 181–94. [33] Sharma R, Kumar H, Kumar G, Sharma S, Aneja R, Sharma AK, et al. Progress and challenges in electrochemical energy storage devices: Fabrication, electrode material, and economic aspects. Chem Eng J 2023;468:143706. [34] Ryu M, Hong Y-K, Lee S-Y, Park JH. Ultrahigh loading dry-process for solvent-free lithium-ion battery electrode fabrication. Nat Commun 2023;14(1):1316. [35] Heidbüchel M, Schultz T, Placke T, Winter M, Koch N, Schmuch R, et al. Enabling Aqueous Processing of Ni-Rich Layered Oxide Cathode Materials by Addition of Lithium Sulfate. ChemSusChem 2023;16(2):e202202161. [36] Lippke M, Ohnimus T, Frankenberg F, Schilde C, Kwade A. Drying and calendering of Lithium Ion battery electrodes: A combined simulation approach. Powder Technol 2024;444:119984. [37] Jin W, Song G, Yoo J-K, Jung S-K, Kim T-H, Kim J. Advancements in Dry Electrode Technologies: Towards Sustainable and Efficient Battery Manufacturing. ChemElectroChem 2024;11(17):e202400288. [38] Sun X, Zhou Y, Li D, Zhao K, Wang L, Tan P, et al. A review of electrospun separators for lithium-based batteries: Progress and application prospects. Carbon Energy 2024;6(9):e539. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 64 [39] Liang Z, Li T, Chi H, Ziegelbauer J, Sun K, Wang M, et al. Solvent-Free Manufacturing of Lithium-Ion Battery Electrodes via Cold Plasma. Energy Environ Mater 2024;7(1):e12503. [40] Liu X, Zeng Y, Yuan W, Zhang G, Zheng H, Chen Z. Advances in multi-scale design and fabrication processes for thick electrodes in lithium-ion batteries. Energy Rev 2024;3(2):100066. [41] Deng J, Ren X, Lin H, Hu L, Bai Y, Yu X, et al. Functionally gradient materials for sustainable and high-energy rechargeable lithium batteries: Design principles, progress, and perspectives. Journal of Energy Chemistry 2024;99:426–49. [42] Zhang X, Hui Z, King ST, Wu J, Ju Z, Takeuchi KJ, et al. Gradient Architecture Design in Scalable Porous Battery Electrodes. Nano Lett 2022;22(6):2521–8. [43] Pfleging W. A review of laser electrode processing for development and manufacturing of lithium-ion batteries. Nanophotonics 2018;7(3):549–73. [44] Ju Z, Zheng T, Calderon J, Checko S, Zhang B, Yu G. Scalable Fast-Charging Aligned Battery Electrodes Enabled by Bidirectional Freeze-Casting. Nano Lett 2023;23(18):8787–93. [45] Dixit MB, Zaman W, Bootwala Y, Zheng Y, Hatzell MC, Hatzell KB. Scalable Manufacturing of Hybrid Solid Electrolytes with Interface Control. ACS Appl Mater Interfaces 2019;11(48):45087–97. [46] W. Pfleging, Ultrafast laser structuring of electrodes to boost electrochemical performance of lithium-ion batteries, Proc´ ed´ es Laser Pour L’Industrie Conf´ erences (PLI 2023), Rennes, Frankreich, 27.09. 2023–28.09. 2023, 2023. [47] Huo S, Sheng L, Su B, Xue W, Wang L, Xu H, et al. 3D Printing Manufacturing of Lithium Batteries: Prospects and Challenges toward Practical Applications. Adv Mater 2024;36(8):2310396. [48] T. B.. Lithium Battery Equipmnet: Everything You Need to Know! 2023. [49] Naseri F, Gil S, Barbu C, Cetkin E, Yarimca G, Jensen AC, et al. Digital twin of electric vehicle battery systems: Comprehensive review of the use cases, requirements, and platforms. Renew Sustain Energy Rev 2023;179:113280. [50] Salado M, Lizundia E, Oyarzabal I, Salazar D. The Role of Critical Raw Materials for Novel Strategies in Sustainable Secondary Batteries, physica status solidi (a) 2022;219(15):2100710. [51] M.a. Markets, Lithium-ion battery market size, share and growth analysis, 2024. [52] Nitta N, Wu F, Lee JT, Yushin G. Li-ion battery materials: present and future. Mater Today 2015;18(5):252–64. [53] Xie J, Lu Y-C. A retrospective on lithium-ion batteries. Nat Commun 2020;11(1):2499. [54] Goodenough JB, Park K-S. The Li-Ion Rechargeable Battery: A Perspective. J Am Chem Soc 2013;135(4):1167–76. [55] G¨ oren A, Costa CM, Silva MM, Lanceros-M´ endez S. State of the art and open questions on cathode preparation based on carbon coated lithium iron phosphate. Compos B Eng 2015;83:333–45. [56] Mishra AK, Monika BSP. A review on recent advances in anode materials in lithium ion batteries. Mater Today Electron 2024;7:100089. [57] Wu Q, Zhang B, Lu Y. Progress and perspective of high-voltage lithium cobalt oxide in lithium-ion batteries. Journal of Energy Chemistry 2022;74:283–308. [58] Costa CM, Gonçalves R, Lanceros-M´ endez S. Advances in Cathode Nanomaterials for Lithium-Ion Batteries. In: Zhen Q, Bashir S, Liu JL, editors. Nanostructured Materials for Next-Generation Energy Storage and Conversion: Advanced Battery and Supercapacitors. Berlin Heidelberg, Berlin, Heidelberg: Springer; 2019. p. 105–45. [59] Britala L, Marinaro M, Kucinskis G. A review of the degradation mechanisms of NCM cathodes and corresponding mitigation strategies. J Storage Mater 2023; 73:108875. [60] Costa CM, Lee Y-H, Kim J-H, Lee S-Y, Lanceros-M´ endez S. Recent advances on separator membranes for lithium-ion battery applications: From porous membranes to solid electrolytes. Energy Storage Mater 2019;22:346–75. [61] Yang Y, Okonkwo EG, Huang G, Xu S, Sun W, He Y. On the sustainability of lithium ion battery industry – A review and perspective. Energy Storage Mater 2021;36:186–212. [62] Narayan R, Laberty-Robert C, Pelta J, Tarascon J-M, Dominko R. Self-Healing: An Emerging Technology for Next-Generation Smart Batteries. Adv Energy Mater 2022;12(17):2102652. [63] Vegge T, Tarascon J-M, Edstr¨ om K. Toward Better and Smarter Batteries by Combining AI with Multisensory and Self-Healing Approaches. Adv Energy Mater 2021;11(23):2100362. [64] Fichtner M, Edstr¨ om K, Ayerbe E, Berecibar M, Bhowmik A, Castelli IE, et al. Rechargeable Batteries of the Future—The State of the Art from a BATTERY 2030 +Perspective. Adv Energy Mater 2022;12(17):2102904. [65] Moradi Z, Lanjan A, Tyagi R, Srinivasan S. Review on current state, challenges, and potential solutions in solid-state batteries research. J Storage Mater 2023; 73:109048. [66] Ahmed MD, Maraz KM. Revolutionizing energy storage: Overcoming challenges and unleashing the potential of next generation Lithium-ion battery technology. Materials Engineering Research 2023;5(1):265–78. [67] Yang Y, Yang S, Xue X, Zhang X, Li Q, Yao Y, et al. Inorganic All-Solid-State Sodium Batteries: Electrolyte Designing and Interface Engineering. Adv Mater 2024;36(1):2308332. [68] Ahmad H, Kubra KT, Butt A, Nisar U, Iftikhar FJ, Ali G. Recent progress, challenges, and perspectives in the development of solid-state electrolytes for sodium batteries. J Power Sources 2023;581:233518. [69] Rudola A, Sayers R, Wright CJ, Barker J. Opportunities for moderate-range electric vehicles using sustainable sodium-ion batteries. Nat Energy 2023;8(3): 215–8. [70] Kim J-S, Yoon G, Kim S, Sugata S, Yashiro N, Suzuki S, et al. Surface engineering of inorganic solid-state electrolytes via interlayers strategy for developing long-cycling quasi-all-solid-state lithium batteries. Nat Commun 2023;14(1):782. [71] K¨ orber N, Lu Y, Friess B, Birke KP. Meso-scale mechanical characterization of polymeric, oxidic and sulfidic solid-state electrolytes until failure. J Storage Mater 2024;83:110643. [72] Yang W, Wang J, Jian J. Metal organic framework-based materials for metal-ion batteries. Energy Storage Mater 2024;66:103249. [73] Zheng M, Li X, Sun J, Wang X, Liu G, Yu W, et al. Research progress on chloride solid electrolytes for all-solid-state batteries. J Power Sources 2024;595: 234051. [74] Zampardi G, La Mantia F. Open challenges and good experimental practices in the research field of aqueous Zn-ion batteries. Nat Commun 2022;13(1):687. [75] Li G, Sun L, Zhang S, Zhang C, Jin H, Davey K, et al. Developing Cathode Materials for Aqueous Zinc Ion Batteries: Challenges and Practical Prospects. Adv Funct Mater 2024;34(5):2301291. [76] Wei J, Zhang P, Sun J, Liu Y, Li F, Xu H, et al. Advanced electrolytes for high-performance aqueous zinc-ion batteries. Chem Soc Rev 2024;53(20):10335–69. [77] Ge H, Xie X, Xie X, Zhang B, Li S, Liang S, et al. Critical challenges and solutions: quasi-solid-state electrolytes for zinc-based batteries. Energ Environ Sci 2024; 17(10):3270–306. [78] Kim SC, Gao X, Liao S-L, Su H, Chen Y, Zhang W, et al. Solvation-property relationship of lithium-sulphur battery electrolytes. Nat Commun 2024;15(1):1268. [79] Wu X, Zhao Y, Li H, Zhou C, Wang X, Du L. Sulfurized polyacrylonitrile as cathodes for advanced lithium–sulfur batteries: advances in modification strategies. Nanoscale 2024;16(10):5060–78. [80] Zhao M, Peng H-J, Li B-Q, Huang J-Q. Kinetic Promoters for Sulfur Cathodes in Lithium–Sulfur Batteries. Acc Chem Res 2024;57(4):545–57. [81] Zhou J, Sun A. Redox mediators for high performance lithium-sulfur batteries: Progress and outlook. Chem Eng J 2024;495:153648. [82] Anchieta CG, Francisco BAB, Júlio JPO, Trtik P, Bonnin A, Doubek G, et al. LiOH Decomposition by NiO/ZrO2 in Li-Air Battery: Chemical Imaging with Operando Synchrotron Diffraction and Correlative Neutron/X-Ray Computed-Tomography Analysis. Small Methods 2024;8(10):2301749. [83] Zhang X, Zhang G, Yang R, Zhang D, Lian G, Hou C, et al. Lattice-dependent activation of highly efficient SnTe cathode catalyst for Li–air batteries. Energy Storage Mater 2024;69:103392. [84] Pan K, Li M, Wang W, Xing S, Dou Y, Gao S, et al. A leap by the rise of solid-state electrolytes for Li-air batteries. Green Energy Environ 2023;8(4):939–44. [85] Zhou T, Shan H, Yu H, Zhong CA, Ge J, Zhang N, Chu W, Yan W, Xu Q, Wu HA, Wu C, Xie Y. Nanopore Confinement of Electrocatalysts Optimizing Triple Transport for an Ultrahigh-Power-Density Zinc–Air Fuel Cell with Robust Stability. Adv Mater 2020;32(47):2003251. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 65 [86] Xu M, Cao R, Hao B, Wang D, Luo D, Dou H, et al. Single-Anion Conductive Solid-State Electrolytes with Hierarchical Ionic Highways for Flexible Zinc-Air Battery. Angew Chem Int Ed 2024;63(36):e202407380. [87] Wang X, Xi B, Ma X, Feng Z, Jia Y, Feng J, et al. Boosting Zinc-Ion Storage Capability by Effectively Suppressing Vanadium Dissolution Based on Robust Layered Barium Vanadate. Nano Lett 2020;20(4):2899–906. [88] Adil M, Sarkar A, Sau S, Muthuraj D, Mitra S. Non-aqueous rechargeable calcium-ion batteries based on high voltage zirconium-doped ammonium vanadium oxide cathode. J Power Sources 2022;541:231669. [89] Chen J, Zhao Z, Niu R, Yao Y, Liang M, Huang Q, et al. Highly stabilized FeS2 cathode design and energy storage mechanism study for advanced aqueous FeS2–Cu battery. J Power Sources 2024;621:235240. [90] Leung OM, Gordon LW, Messinger RJ, Prodromakis T, Wharton JA, Ponce de Le´ on C, et al. Solid Polymer Electrolytes with Enhanced Electrochemical Stability for High-Capacity Aluminum Batteries. Adv Energy Mater 2024;14(8):2303285. [91] Greim P, Solomon AA, Breyer C. Assessment of lithium criticality in the global energy transition and addressing policy gaps in transportation. Nat Commun 2020;11(1):4570. [92] Picatoste A, Schulz-M¨ onninghoff M, Niero M, Justel D, Mendoza JMF. Comparing the circularity and life cycle environmental performance of batteries for electric vehicles. Resour Conserv Recycl 2024;210:107833. [93] Liu Y-K, Zhao C-Z, Du J, Zhang X-Q, Chen A-B, Zhang Q. Research Progresses of Liquid Electrolytes in Lithium-Ion Batteries. Small 2023;19(8):2205315. [94] Kainat S, Anwer J, Hamid A, Gull N, Khan SM. Electrolytes in Lithium-Ion Batteries: Advancements in the Era of Twenties (2020’s). Mater Chem Phys 2024; 313:128796. [95] Liu M, Zeng Z, Wu Y, Zhong W, Lei S, Cheng S, et al. Reviewing recent progress of liquid electrolyte chemistry for mitigating thermal runaway in lithium–ion batteries. Energy Storage Mater 2024;65:103133. [96] Zheng Y, Shen Y, Guo J, Li J, Wang J, Ning D, et al. Recent advances in solid-state lithium batteries based on anode engineering. Nano Research Energy 2024;3: e9120118. [97] Wu M, Han S, Liu S, Zhao J, Xie W. Fire-safe polymer electrolyte strategies for lithium batteries. Energy Storage Mater 2024;66:103174. [98] Nguyen A-G, Lee M-H, Kim J, Park C-J. Construction of a High-Performance Composite Solid Electrolyte Through In-Situ Polymerization within a SelfSupported Porous Garnet Framework. Nano-Micro Letters 2024;16(1):83. [99] Sau K, Takagi S, Ikeshoji T, Kisu K, Sato R, dos Santos EC, et al. Unlocking the secrets of ideal fast ion conductors for all-solid-state batteries. Communications Materials 2024;5(1):122. [100] Raza S, Bashir T, Hayat A, Abd-Rabboh HSM, Shen L, Orooji Y, et al. Recent progress and fundamentals of solid-state electrolytes for all solid-state rechargeable batteries: Mechanisms, challenges, and applications. J Storage Mater 2024;92:112110. [101] Ko JS, Hamann T, Fortunato J, Augustyn V. Recent Advances in Electrolytes for Enabling Lithium-Ion Batteries across a Wide Temperature Range. J Phys Chem C 2024;128(8):3113–26. [102] He P, Tang Y, Tan Z, Lei C, Qin Z, Li Y, et al. Solid-state batteries encounter challenges regarding the interface involving lithium metal. Nano Energy 2024;124: 109502. [103] BATTERIES EUROPE SECRETARIAT D3.6-KPIs Benchmarking & Target KPIs. . [104] Quartarone E, Mustarelli P. Review—Emerging Trends in the Design of Electrolytes for Lithium and Post-Lithium Batteries. J Electrochem Soc 2020;167(5): 050508. [105] Agrawal RC, Pandey GP. Solid polymer electrolytes: materials designing and all-solid-state battery applications: an overview. J Phys D Appl Phys 2008;41(22): 223001. [106] Yang H, Wu N. Ionic conductivity and ion transport mechanisms of solid-state lithium-ion battery electrolytes: A review. Energy Sci Eng 2022;10(5):1643–71. [107] Gali´ nski M, Lewandowski A, Stępniak I. Ionic liquids as electrolytes. Electrochim Acta 2006;51(26):5567–80. [108] Armand M. The history of polymer electrolytes. Solid State Ion 1994;69(3):309–19. [109] Quartarone E, Mustarelli P, Magistris A. PEO-based composite polymer electrolytes. Solid State Ion 1998;110(1):1–14. [110] Jagan M, Vijayachamundeeswari SP. The significance of fillers in composite polymer electrolytes for optimizing lithium battery. Ionics 2024;30(2):647–75. [111] D.K. Maurya, B. Bazri, P. Srivastava, J.-Y. Huang, Y.-T. Hung, W.-T. Huang, D.-H. Wei, R.-S. Liu, Ceramic Rich Composite Electrolytes: An Overview of Paradigm Shift toward Solid Electrolytes for High-Performance Lithium-Metal Batteries, Advanced Energy Materials n/a(n/a) 2402402. [112] Song JY, Wang YY, Wan CC. Review of gel-type polymer electrolytes for lithium-ion batteries. J Power Sources 1999;77(2):183–97. [113] Aruchamy K, Ramasundaram S, Divya S, Chandran M, Yun K, Oh TH. Gel Polymer Electrolytes: Advancing Solid-State Batteries for High-Performance Applications. Gels 2023;9(7):585. [114] Gentili V, Panero S, Reale P, Scrosati B. Composite gel-type polymer electrolytes for advanced, rechargeable lithium batteries. J Power Sources 2007;170(1): 185–90. [115] Fergus JW. Ceramic and polymeric solid electrolytes for lithium-ion batteries. J Power Sources 2010;195(15):4554–69. [116] Wang Z, Luo S-H, Zhang X, Guo S, Li P, Yan S. Glass and glass ceramic electrodes and solid electrolyte materials for lithium ion batteries: A review. J Non Cryst Solids 2023;619:122581. [117] Yin J-H, Zhu H, Yu S-J, Dong Y-B, Wei Q-Y, Xu G-Q, et al. Recent Advances of LATP and Their NASICON Structure as a Solid-State Electrolyte for Lithium-Ion Batteries. Adv Eng Mater 2023;25(20):2300566. [118] Luo C, Yi M, Cao Z, Hui W, Wang Y. Review of Ionic Conductivity Properties of NASICON Type Inorganic Solid Electrolyte LATP. ACS Appl Electron Mater 2024;6(2):641–57. [119] Wang Y, Chen Z, Jiang K, Shen Z, Passerini S, Chen M. Accelerating the Development of LLZO in Solid-State Batteries Toward Commercialization: A Comprehensive Review. Small 2024;20(35):2402035. [120] Wang J-C, Li Y, Li Z-X, Wang P-F, Zhu Y-R, Sun Y, et al. Review on Interface Issues between a Garnet Li7La3Zr2O12 Solid Electrolyte and Li Anode: Advances and Perspectives. Energy Fuel 2024;38(14):12528–45. [121] Z. Zou, Z. Xiao, Z. Lin, B. Zhang, C. Zhang, F. Wei, Lithium Phosphorous Oxynitride as an Advanced Solid-State Electrolyte to Boost High-Energy Lithium Metal Battery, Advanced Functional Materials n/a(n/a) 2409330. [122] Dai W, Qiao Y, Ma Z, Wang T, Fu Z. All-solid-state thin-film batteries based on lithium phosphorus oxynitrides. Materials Futures 2022;1(3):032101. [123] Goodenough JB, Hong HYP, Kafalas JA. Fast Na+-ion transport in skeleton structures. Mater Res Bull 1976;11(2):203–20. [124] Hong HYP. Crystal structure and ionic conductivity of Li14Zn(GeO4)4 and other new Li+superionic conductors. Mater Res Bull 1978;13(2):117–24. [125] Krauskopf T, Culver SP, Zeier WG. Bottleneck of Diffusion and Inductive Effects in Li10Ge1–xSnxP2S12. Chem Mater 2018;30(5):1791–8. [126] Kamaya N, Homma K, Yamakawa Y, Hirayama M, Kanno R, Yonemura M, et al. A lithium superionic conductor. Nat Mater 2011;10(9):682–6. [127] Ohara K, Mitsui A, Mori M, Onodera Y, Shiotani S, Koyama Y, et al. Structural and electronic features of binary Li2S-P2S5 glasses. Sci Rep 2016;6(1):21302. [128] Warren Z, Rosero-Navarro NC. Solution-Based Suspension Synthesis of Li2S–P2S5 Glass-Ceramic Systems as Solid-State Electrolytes: A Brief Review of Current Research. ACS Omega 2024;9(29):31228–36. [129] Kato Y, Hori S, Saito T, Suzuki K, Hirayama M, Mitsui A, et al. High-power all-solid-state batteries using sulfide superionic conductors. Nat Energy 2016;1(4): 16030. [130] Kanno R, Murayama M. Lithium Ionic Conductor Thio-LISICON: The Li2 S - GeS2 - P 2 S 5 System. J Electrochem Soc 2001;148(7):A742. [131] Luo M, Wang C, Duan Y, Zhao X, Wang J, Sun X. Surface Coating Enabling Sulfide Solid Electrolytes with Excellent Air Stability and Lithium Compatibility. Energy Environ Mater 2024;7(6):e12753. [132] Zhen Y, Yang W, Qin Z, Ji M, Qie Y, Li J, et al. Improved ionic conductivity and air stability of Li7P3S11 by SnSe2 doping and two-step pressing sintering method. Electrochim Acta 2024;503:144888. [133] Yang J, Jiang Z, Liu C, Li L, Li S, Wu Z, et al. Tin-based dual-modification enabling enhanced air stability and electrochemical performance for Li5.5PS4.5Cl1.5 in all-solid-state lithium metal batteries. Chem Eng J 2024;500:157027. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 66 [134] Helm B, Strotmann K, B¨ oger T, Samanta B, Banik A, Lange MA, et al. Reducing the Defect Formation Energy by Aliovalent Sn(+IV) and Isovalent P(+V) Substitution in Li3SbS4 Promotes Li+Transport. ACS Appl Energy Mater 2024;7(5):1735–47. [135] Zhang N, He Q, Zhang L, Zhang J, Huang L, Yao X. Homogeneous Fluorine Doping toward Highly Conductive and Stable Li10GeP2S12 Solid Electrolyte for AllSolid-State Lithium Batteries. Adv Mater 2024;36(36):2408903. [136] Wang Q, Zhou Y, Wang X, Guo H, Gong S, Yao Z, et al. Designing lithium halide solid electrolytes. Nat Commun 2024;15(1):1050. [137] Li X, Kim JT, Luo J, Zhao C, Xu Y, Mei T, et al. Structural regulation of halide superionic conductors for all-solid-state lithium batteries. Nat Commun 2024;15 (1):53. [138] Chen S, Yu C, Chen S, Peng L, Liao C, Wei C, et al. Enabling ultrafast lithium-ion conductivity of Li2ZrCl6 by indium doping. Chin Chem Lett 2022;33(10): 4635–9. [139] Rosa C, Ravalli M, Pianta N, Mustarelli P, Ferrara C, Quartarone E, et al. Aliovalent Substitution in Li3InCl6: A Combined Experimental and Computational Investigation of Structure and Ion Diffusion in Lithium-Halide Solid State Electrolytes. ACS Appl Energy Mater 2024;7(10):4314–23. [140] Banik A, Samanta B, Helm B, Kraft MA, Rudel Y, Li C, et al. Exploring Layered Disorder in Lithium-Ion-Conducting Li3Y1–xInxCl6. Inorg Chem 2024;63(19): 8698–709. [141] Liu X-K, Zhou Y-X, Mi F-H, Ma X-L, Sun C-W. Superionic halide solid electrolyte Li1.7Zr0.7Ta0.3Cl6 for durable all-solid-state lithium batteries. Energy Storage Mater 2024;72:103737. [142] Miyazaki R, Yamaguchi G, Yagi E, Yoshida T, Tomita T. Enhancement of the Li+Conductivity of Li3AlF6 for Stable All-Solid-State Lithium-Ion Batteries. ACS Appl Energy Mater 2024;7(6):2533–41. [143] Sun A, Tu H, Sun Z, He Z, Wang Y, Wang J, et al. Dual-Halide Interphase Enabling High-Performance Lithium Metal Batteries in Wide-Temperature Range. ACS Energy Lett 2024;9(6):2545–53. [144] Chen HM, Maohua C, Adams S. Stability and ionic mobility in argyrodite-related lithium-ion solid electrolytes. PCCP 2015;17(25):16494–506. [145] Park J-S, Jo C-H, Myung S-T. Comprehensive understanding on lithium argyrodite electrolytes for stable and safe all-solid-state lithium batteries. Energy Storage Mater 2023;61:102869. [146] Deiseroth H-J, Kong S-T, Eckert H, Vannahme J, Reiner C, Zaiß T, et al. Li6PS5X: A Class of Crystalline Li-Rich Solids With an Unusually High Li+Mobility. Angew Chem Int Ed 2008;47(4):755–8. [147] Adeli P, Bazak JD, Park KH, Kochetkov I, Huq A, Goward GR, et al. Boosting Solid-State Diffusivity and Conductivity in Lithium Superionic Argyrodites by Halide Substitution. Angew Chem Int Ed 2019;58(26):8681–6. [148] Kraft MA, Ohno S, Zinkevich T, Koerver R, Culver SP, Fuchs T, et al. Inducing High Ionic Conductivity in the Lithium Superionic Argyrodites Li6+xP1–xGexS5I for All-Solid-State Batteries. J Am Chem Soc 2018;140(47):16330–9. [149] Yu C, Zhao F, Luo J, Zhang L, Sun X. Recent development of lithium argyrodite solid-state electrolytes for solid-state batteries: Synthesis, structure, stability and dynamics. Nano Energy 2021;83:105858. [150] Wang J, Chen F, Hu L, Ma C. Alternate Crystal Structure Achieving Ionic Conductivity above 1 mS cm–1 in Cost-Effective Zr-Based Chloride Solid Electrolytes. Nano Lett 2023;23(13):6081–7. [151] Tanaka Y, Ueno K, Mizuno K, Takeuchi K, Asano T, Sakai A. New Oxyhalide Solid Electrolytes with High Lithium Ionic Conductivity >10 mS cm−1 for AllSolid-State Batteries. Angew Chem Int Ed 2023;62(13):e202217581. [152] Hu L, Wang J, Wang K, Gu Z, Xi Z, Li H, et al. A cost-effective, ionically conductive and compressible oxychloride solid-state electrolyte for stable all-solid-state lithium-based batteries. Nat Commun 2023;14(1):3807. [153] Quartarone E, Mustarelli P. Electrolytes for solid-state lithium rechargeable batteries: recent advances and perspectives. Chem Soc Rev 2011;40(5):2525–40. [154] Xi G, Xiao M, Wang S, Han D, Li Y, Meng Y. Polymer-Based Solid Electrolytes: Material Selection, Design, and Application. Adv Funct Mater 2021;31(9): 2007598. [155] Sanchez J-Y, Alloin F, Saunier J. Chapter 14 - PVdF-based polymers for lithium batteries. In: Nakajima T, Groult H, editors. Fluorinated Materials for Energy Conversion. Amsterdam: Elsevier Science; 2005. p. 305–33. [156] Meyer WH. Polymer Electrolytes for Lithium-Ion Batteries. Adv Mater 1998;10(6):439–48. [157] Gao J, Wang C, Han D-W, Shin D-M. Single-ion conducting polymer electrolytes as a key jigsaw piece for next-generation battery applications. Chem Sci 2021; 12(40):13248–72. [158] Raphael E, Avellaneda CO, Manzolli B, Pawlicka A. Agar-based films for application as polymer electrolytes. Electrochim Acta 2010;55(4):1455–9. [159] Wang Z-L, Tang Z-Y. A novel polymer electrolyte based on PMAML/PVDF-HFP blend. Electrochim Acta 2004;49(7):1063–8. [160] Croce F, Persi L, Ronci F, Scrosati B. Nanocomposite polymer electrolytes and their impact on the lithium battery technology. Solid State Ion 2000;135(1): 47–52. [161] Chen S, Wen K, Fan J, Bando Y, Golberg D. Progress and future prospects of high-voltage and high-safety electrolytes in advanced lithium batteries: from liquid to solid electrolytes. J Mater Chem A 2018;6(25):11631–63. [162] Fenton DE, Parker JM, Wright PV. Complexes of alkali metal ions with poly(ethylene oxide). Polymer 1973;14(11):589. [163] Marzantowicz M, Dygas JR, Krok F, Florja´ nczyk Z, Zygadło-Monikowska E. Influence of crystalline complexes on electrical properties of PEO:LiTFSI electrolyte. Electrochim Acta 2007;53(4):1518–26. [164] Halder B, Mohamed MG, Kuo S-W, Elumalai P. Review on composite polymer electrolyte using PVDF-HFP for solid-state lithium-ion battery. Mater Today Chem 2024;36:101926. [165] Armand M, Axmann P, Bresser D, Copley M, Edstr¨ om K, Ekberg C, et al. Lithium-ion batteries – Current state of the art and anticipated developments. J Power Sources 2020;479:228708. [166] Hoang Huy VP, So S, Hur J. Inorganic Fillers in Composite Gel Polymer Electrolytes for High-Performance Lithium and Non-Lithium Polymer Batteries. Nanomaterials 2021;11(3):614. [167] Zhou S, Zhong S, Dong Y, Liu Z, Dong L, Yuan B, et al. Composition and Structure Design of Poly(vinylidene fluoride)-Based Solid Polymer Electrolytes for Lithium Batteries. Adv Funct Mater 2023;33(20):2214432. [168] Wieczorek W, Florjanczyk Z, Stevens JR. Composite polyether based solid electrolytes. Electrochim Acta 1995;40(13):2251–8. [169] Fu J, Li Z, Zhou X, Guo X. Ion transport in composite polymer electrolytes. Mater Adv 2022;3(9):3809–19. [170] Huo H, Chen Y, Luo J, Yang X, Guo X, Sun X. Rational Design of Hierarchical “Ceramic-in-Polymer” and “Polymer-in-Ceramic” Electrolytes for Dendrite-Free Solid-State Batteries. Adv Energy Mater 2019;9(17):1804004. [171] Han L, Lehmann ML, Zhu J, Liu T, Zhou Z, Tang X, et al. Recent Developments and Challenges in Hybrid Solid Electrolytes for Lithium-Ion Batteries. Front Energy Res 2020;8. [172] Gao H, Grundish NS, Zhao Y, Zhou A, Goodenough JB. Formation of Stable Interphase of Polymer-in-Salt Electrolyte in All-Solid-State Lithium Batteries. Energy Mater Adv 2021;2021. [173] Zhao T, Gai Q, Deng X, Ma J, Gao H. A new type of LATP doped PVDF-HFP based electrolyte membrane with flame retardancy and long cycle stability for solid state batteries. J Storage Mater 2023;73:108576. [174] Wang C, Bai G, Yang Y, Liu X, Shao H. Dendrite-free all-solid-state lithium batteries with lithium phosphorous oxynitride-modified lithium metal anode and composite solid electrolytes. Nano Res 2019;12(1):217–23. [175] Capiglia C, Mustarelli P, Quartarone E, Tomasi C, Magistris A. Effects of nanoscale SiO2 on the thermal and transport properties of solvent-free, poly(ethylene oxide) (PEO)-based polymer electrolytes. Solid State Ion 1999;118(1):73–9. [176] Pandian AS, Chen XC, Chen J, Lokitz BS, Ruther RE, Yang G, et al. Facile and scalable fabrication of polymer-ceramic composite electrolyte with high ceramic loadings. J Power Sources 2018;390:153–64. [177] Chen A, Qu C, Shi Y, Shi F. Manufacturing Strategies for Solid Electrolyte in Batteries. Front Energy Res 2020;8. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 67 [178] Song Z, Chen F, Martinez-Iba˜ nez M, Feng W, Forsyth M, Zhou Z, et al. A reflection on polymer electrolytes for solid-state lithium metal batteries. Nat Commun 2023;14(1):4884. [179] Chen L, Li Y, Li S-P, Fan L-Z, Nan C-W, Goodenough JB. PEO/garnet composite electrolytes for solid-state lithium batteries: From “ceramic-in-polymer” to “polymer-in-ceramic”. Nano Energy 2018;46:176–84. [180] McLachlan DS. Measurement and analysis of a model dual-conductivity medium using a generalised effective-medium theory. J Phys C Solid State Phys 1988; 21(8):1521. [181] Hailu Mengesha T, Lemma Beshahwured S, Wu Y-S, Wu S-H, Jose R, Yang C-C. A polydopamine-modified garnet–based polymer-in-ceramic hybrid solid electrolyte membrane for high-safety lithium metal batteries. Chem Eng J 2023;452:139340. [182] Wang Q, Wang S, Lu T, Guan L, Hou L, Du H, et al. Ultrathin Solid Polymer Electrolyte Design for High-Performance Li Metal Batteries: A Perspective of Synthetic Chemistry. Adv Sci 2023;10(1):2205233. [183] Bonizzoni S, Ferrara C, Berbenni V, Anselmi-Tamburini U, Mustarelli P, Tealdi C. NASICON-type polymer-in-ceramic composite electrolytes for lithium batteries. PCCP 2019;21(11):6142–9. [184] Colombo F, Bonizzoni S, Ferrara C, Simonutti R, Mauri M, Falco M, et al. Polymer-in-Ceramic Nanocomposite Solid Electrolyte for Lithium Metal Batteries Encompassing PEO-Grafted TiO2 Nanocrystals. J Electrochem Soc 2020;167(7):070535. [185] Jiang H, Wu Y, Ma J, Liu Y, Wang L, Yao X, et al. Ultrathin polymer-in-ceramic and ceramic-in-polymer bilayer composite solid electrolyte membrane for highvoltage lithium metal batteries. J Membr Sci 2021;640:119840. [186] Wang Z, Liu R, Ba Z, Xu K, Li X, Dong J, et al. Built-in garnet-rich composite solid electrolyte towards fast ion transport and dendrite-free for high-energy lithium batteries. Compos Commun 2024;47:101871. [187] Zhang X, Wang S, Xue C, Xin C, Lin Y, Shen Y, et al. Self-Suppression of Lithium Dendrite in All-Solid-State Lithium Metal Batteries with Poly(vinylidene difluoride)-Based Solid Electrolytes. Adv Mater 2019;31(11):1806082. [188] Callegari D, Bonizzoni S, Berbenni V, Quartarone E, Mustarelli P. Is It Possible to Obtain Solvent-Free, Li+-Conducting Solid Electrolytes Based on Pure PVdF? Comment on “Self-Suppression of Lithium Dendrite in All-Solid-State Lithium Metal Batteries with Poly(vinylidene difluoride)-Based Solid Electrolytes”. Adv Mater 2020;32(14):1907375. [189] Vallana N, Carena E, Ceribelli N, Mezzomo L, Di Liberto G, Mauri M, et al. Host–Guest Interactions and Transport Mechanism in Poly(vinylidene fluoride)- Based Quasi-Solid Electrolytes for Lithium Metal Batteries. ACS Appl Energy Mater 2024;7(4):1606–17. [190] Carena E, Mezzomo L, Vallana N, Ceribelli N, Di Liberto G, Mostoni S, et al. PVDF-HFP Based, Quasi-Solid Nanocomposite Electrolytes for Lithium Metal Batteries. Small 2024;20(30):2311805. [191] Nguyen A-G, Park C-J. Insights into tailoring composite solid polymer electrolytes for solid-state lithium batteries. J Membr Sci 2023;675:121552. [192] He R, Kyu T. Effect of Plasticization on Ionic Conductivity Enhancement in Relation to Glass Transition Temperature of Crosslinked Polymer Electrolyte Membranes. Macromolecules 2016;49(15):5637–48. [193] Zhang H, Oteo U, Zhu H, Judez X, Martinez-Iba˜ nez M, Aldalur I, et al. Enhanced Lithium-Ion Conductivity of Polymer Electrolytes by Selective Introduction of Hydrogen into the Anion. Angew Chem Int Ed 2019;58(23):7829–34. [194] Qiao L, Rodriguez Pe˜ na S, Martínez-Iba˜ nez M, Santiago A, Aldalur I, Lobato E, et al. Anion π – π Stacking for Improved Lithium Transport in Polymer Electrolytes. J Am Chem Soc 2022;144(22):9806–16. [195] Zhu X, Wang K, Xu Y, Zhang G, Li S, Li C, et al. Strategies to Boost Ionic Conductivity and Interface Compatibility of Inorganic - Organic Solid Composite Electrolytes. Energy Storage Mater 2021;36:291–308. [196] Chi S-S, Liu Y, Zhao N, Guo X, Nan C-W, Fan L-Z. Solid polymer electrolyte soft interface layer with 3D lithium anode for all-solid-state lithium batteries. Energy Storage Mater 2019;17:309–16. [197] Yang C, Xie H, Ping W, Fu K, Liu B, Rao J, et al. An Electron/Ion Dual-Conductive Alloy Framework for High-Rate and High-Capacity Solid-State Lithium-Metal Batteries. Adv Mater 2019;31(3):1804815. [198] Tang J, Wang L, Tian C, Huang T, Zhang J, Zeng L, et al. Multilayer structure solid-state electrolyte composite membranes for long-life quasi-solid-state battery. J Alloy Compd 2023;960:170736. [199] Hu Y, Li W, Zhu J, Hao S-M, Qin X, Fan L-Z, et al. Multi-layered electrolytes for solid-state lithium batteries. Next Energy 2023;1(3):100042. [200] Nie K, Hong Y, Qiu J, Li Q, Yu X, Li H, et al. Interfaces Between Cathode and Electrolyte in Solid State Lithium Batteries: Challenges and Perspectives. Front Chem 2018;6. [201] Xiao Y, Miara LJ, Wang Y, Ceder G. Computational Screening of Cathode Coatings for Solid-State Batteries. Joule 2019;3(5):1252–75. [202] Khan K, Fu B, Xin H, Beshiwork BA, Hanif MB, Wu J, et al. Composite polymer electrolyte incorporating WO3 nanofillers with enhanced performance for dendrite-free solid-state lithium battery. Ceram Int 2023;49(3):4473–81. [203] Li G, Monroe CW. Dendrite nucleation in lithium-conductive ceramics. PCCP 2019;21(36):20354–9. [204] Gaines L, Cuenca R. Costs of lithium-ion batteries for vehicles. IL (US): Argonne National Lab; 2000. [205] Ahuis M, Doose S, Vogt D, Michalowski P, Zellmer S, Kwade A. Recycling of solid-state batteries. Nat Energy 2024;9(4):373–85. [206] Bauer A, Song J, Vail S, Pan W, Barker J, Lu Y. The Scale-up and Commercialization of Nonaqueous Na-Ion Battery Technologies. Adv Energy Mater 2018;8 (17):1702869. [207] Saw LH, Ye Y, Tay AAO. Integration issues of lithium-ion battery into electric vehicles battery pack. J Clean Prod 2016;113:1032–45. [208] Lin J, Liu X, Li S, Zhang C, Yang S. A review on recent progress, challenges and perspective of battery thermal management system. Int J Heat Mass Transf 2021;167:120834. [209] Huang S, Wang Z, Von Lim Y, Wang Y, Li Y, Zhang D, et al. Recent Advances in Heterostructure Engineering for Lithium–Sulfur Batteries. Adv Energy Mater 2021;11(10):2003689. [210] Hu Y, Chen W, Lei T, Jiao Y, Huang J, Hu A, et al. Strategies toward High-Loading Lithium–Sulfur Battery. Adv Energy Mater 2020;10(17):2000082. [211] Chen Y, Xu J, He P, Qiao Y, Guo S, Yang H, et al. Metal-air batteries: progress and perspective. Science Bulletin 2022;67(23):2449–86. [212] Pan J, Xu YY, Yang H, Dong Z, Liu H, Xia BY. Advanced Architectures and Relatives of Air Electrodes in Zn–Air Batteries. Adv Sci 2018;5(4):1700691. [213] Liu Q, Pan Z, Wang E, An L, Sun G. Aqueous metal-air batteries: Fundamentals and applications. Energy Storage Mater 2020;27:478–505. [214] Borchardt L, Oschatz M, Kaskel S. Carbon Materials for Lithium Sulfur Batteries—Ten Critical Questions, Chemistry – A. European Journal 2016;22(22): 7324–51. [215] Liu Q, Lin Y, Zong Z, Sun G, Li Q. Lightweight design of carbon twill weave fabric composite body structure for electric vehicle. Compos Struct 2013;97:231–8. [216] Snyder JF, Wong EL, Hubbard CW. Evaluation of Commercially Available Carbon Fibers, Fabrics, and Papers for Potential Use in Multifunctional Energy Storage Applications. J Electrochem Soc 2009;156(3):A215. [217] Snyder J, Carter R, Wong E, Nguyen P, Xu K, Ngo E, et al. Multifunctional Structural Composite Batteries, International SAMPE Technical Conference 2007:18. [218] Wong E, Baechle D, Xu K, Carter R, Snyder J, Wetzel E. Design and Processing of Structural Composite Batteries. International SAMPE Symposium and Exhibition (Proceedings) 2007;52:20. [219] South JT, Carter RH, Snyder JF, Hilton CD, O’Brien DJ, Wetzel ED. Multifunctional Power-Generating and Energy-Storing Structural Composites for U.S. Army Applications. MRS Online Proc Libr 2004;851(1):269–80. [220] Johannisson W, Zenkert D, Lindbergh G. Model of a structural battery and its potential for system level mass savings. Multifunct Mater 2019;2(3):035002. [221] Hopkins BJ, Long JW, Rolison DR, Parker JF. High-Performance Structural Batteries. Joule 2020;4(11):2240–3. [222] Galos J, Best AS, Mouritz AP. Multifunctional sandwich composites containing embedded lithium-ion polymer batteries under bending loads. Mater Des 2020; 185:108228. [223] Chen J, Zhou Y, Islam MS, Cheng X, Brown SA, Han Z, et al. Carbon fiber reinforced Zn–MnO2 structural composite batteries. Compos Sci Technol 2021;209: 108787. [224] Pyo J, Park H-W, Jang M-S, Choi J-S, Sathish Kumar SK, Kim C-G. Tubular laminated composite structural battery. Compos Sci Technol 2021;208:108646. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 68 [225] Mao Y-Q, Dong G-H, Fu Y-T, Li Y-Q, Huang P, Fu S-Y. High performance shape-adjustable structural lithium-ion battery based on hybrid fiber reinforced epoxy composite. Compos Struct 2023;325:117598. [226] Thakur A, Dong X. Printing with 3D continuous carbon fiber multifunctional composites via UV-assisted coextrusion deposition. Manuf Lett 2020;24:1–5. [227] Pappas JM, Thakur AR, Dong X. Effects of cathode doping on 3D printed continuous carbon fiber structural battery composites by UV-assisted coextrusion deposition. J Compos Mater 2021;55(26):3893–908. [228] Qian J, Chen Q, Hong M, Xie W, Jing S, Bao Y, et al. Toward stretchable batteries: 3D-printed deformable electrodes and separator enabled by nanocellulose. Mater Today 2022;54:18–26. [229] Chaudhary R, Xu J, Xia Z, Asp LE. Unveiling the Multifunctional Carbon Fiber Structural Battery. Advanced Materials n/a(n/a) 2024:2409725. [230] Xu J, Geng Z, Johansen M, Carlstedt D, Duan S, Thiringer T, et al. A multicell structural battery composite laminate. EcoMat 2022;4(3):e12180. [231] Kjell MH, Jacques E, Zenkert D, Behm M, Lindbergh G. PAN-Based Carbon Fiber Negative Electrodes for Structural Lithium-Ion Batteries. J Electrochem Soc 2011;158(12):A1455. [232] Ladpli P, Nardari R, Kopsaftopoulos F, Chang F-K. Multifunctional energy storage composite structures with embedded lithium-ion batteries. J Power Sources 2019;414:517–29. [233] Moyer K, Boucherbil NA, Zohair M, Eaves-Rathert J, Pint CL. Polymer reinforced carbon fiber interfaces for high energy density structural lithium-ion batteries. Sustainable Energy Fuels 2020;4(6):2661–8. [234] Moyer K, Meng C, Marshall B, Assal O, Eaves J, Perez D, et al. Carbon fiber reinforced structural lithium-ion battery composite: Multifunctional power integration for CubeSats. Energy Storage Mater 2020;24:676–81. [235] Choi J-S, Park H-W, Noh J-E, Cha J, Jang W-H, Kim C-G. Composite-fabric-based structure-integrated energy storage system. Compos Struct 2023;310:116757. [236] Hahn M, Buqa H, Ruch PW, Goers D, Spahr ME, Ufheil J, et al. A Dilatometric Study of Lithium Intercalation into Powder-Type Graphite Electrodes. Electrochem Solid St 2008;11(9):A151. [237] Qi Y, Guo H, Hector LG, Timmons A. Threefold Increase in the Young’s Modulus of Graphite Negative Electrode during Lithium Intercalation. J Electrochem Soc 2010;157(5):A558. [238] Zhang P, Ma Z, Wang Y, Zou Y, Sun L, Lu C. Lithiation-induced interfacial failure of electrode-collector: A first-principles study. Mater Chem Phys 2019;222: 193–9. [239] Zhao Y, Stein P, Bai Y, Al-Siraj M, Yang Y, Xu B-X. A review on modeling of electro-chemo-mechanics in lithium-ion batteries. J Power Sources 2019;413: 259–83. [240] Verma A, Kotaka T, Tabuchi Y, Mukherjee PP. Mechano-Electrochemical Interaction and Degradation in Graphite Electrode with Surface Film. J Electrochem Soc 2018;165(10):A2397. [241] Jacques E, Hellqvist Kjell M, Zenkert D, Lindbergh G, Behm M. Expansion of carbon fibres induced by lithium intercalation for structural electrode applications. Carbon 2013;59:246–54. [242] Mao R, Lei Z, Liu X, Li Q, Zhong J, Bai R, et al. Study on electrochemical lithiation stress model of graphite-carbon fiber bilayer electrode. Carbon 2024;226: 119214. [243] Park H-W, Jang M-S, Choi J-S, Pyo J, Kim C-G. Characteristics of woven carbon fabric current collector electrodes for structural battery. Compos Struct 2021; 256:112999. [244] Zhou G, Li F, Cheng H-M. Progress in flexible lithium batteries and future prospects. Energy Environmental Science 2014;7(4):1307–38. [245] Xu K. Electrolytes and interphases in Li-ion batteries and beyond. Chem Rev 2014;114(23):11503–618. [246] Asp LE, Johansson M, Lindbergh G, Xu J, Zenkert D. Structural battery composites: a review. Funct Compos Struct 2019;1(4):042001. [247] Tikekar MD, Archer LA, Koch DL. Stabilizing electrodeposition in elastic solid electrolytes containing immobilized anions. Sci Adv 2016;2(7):e1600320. [248] Liu P, Sherman E, Jacobsen A. Design and fabrication of multifunctional structural batteries. J Power Sources 2009;189(1):646–50. [249] Dong G-H, Mao Y-Q, Yang G-M, Li Y-Q, Song S-F, Xu C-H, et al. High-Strength Poly (ethylene oxide) Composite Electrolyte Reinforced with Glass Fiber and Ceramic Electrolyte Simultaneously for Structural Energy Storage. ACS Appl Energy Mater 2021;4(4):4038–49. [250] Shirshova N, Bismarck A, Carreyette S, Fontana QP, Greenhalgh ES, Jacobsson P, et al. Structural supercapacitor electrolytes based on bicontinuous ionic liquid–epoxy resin systems 2013;1(48):15300–9. [251] Shirshova N, Bismarck A, Greenhalgh ES, Johansson P, Kalinka G, Marczewski MJ, et al. MJTJoPCC Wienrich, Composition as a means to control morphology and properties of epoxy based dual-phase structural electrolytes 2014;118(49):28377–87. [252] Ihrner N, Johannisson W, Sieland F, Zenkert D, Johansson M. Structural lithium ion battery electrolytes via reaction induced phase-separation. J Mater Chem A 2017;5(48):25652–9. [253] Johannisson W, Ihrner N, Zenkert D, Johansson M, Carlstedt D, Asp LE, et al. Multifunctional performance of a carbon fiber UD lamina electrode for structural batteries. Composites Science Technology 2018;168:81–7. [254] D. Carlstedt, W. Johannisson, D. Zenkert, P. Linde, L.E. Asp, Conceptual design framework for laminated structural battery composites, Proc. 18th Eur. Conf. Compos. Mater., Athens, Greece, 2018, pp. 24-8. [255] Schneider LM, Ihrner N, Zenkert D, Johansson M. Bicontinuous electrolytes via thermally initiated polymerization for structural lithium ion batteries. ACS Appl Energy Mater 2019;2(6):4362–9. [256] Asp LE, Bouton K, Carlstedt D, Duan S, Harnden R, Johannisson W, et al. A structural battery and its multifunctional performance. Advanced Energy Sustainability Research 2021;2(3):2000093. [257] Dong G-H, Mao Y-Q, Guo F-L, Li Y-Q, Huang P, Fu S-Y. Structural battery composites with remarkable energy storage capabilities via system structural design. Compos Struct 2023;306:116615. [258] Scholz AE, Hermanutz A, Hornung M. Feasibility analysis and comparative assessment of structural power technology in all-electric composite aircraft. Deutscher Luft-und Raumfahrtkongress; 2018. [259] Thomas JP, Qidwai SM, Pogue WR, Pham GT. Multifunctional structure-battery composites for marine systems. J Compos Mater 2012;47(1):5–26. [260] Han Z, Zhu J, Feng Y, Zhang W, Xiong Y, Zhang W. Manufacturing carbon fabric composite structural batteries using spray with high-pressure and hightemperature and vacuum-bag assisted infusion techniques. Compos Sci Technol 2024;245:110321. [261] Landowski M, Strugała G, Budzik M, Imieli´ nska K. Impact damage in SiO2 nanoparticle enhanced epoxy – Carbon fibre composites. Compos B Eng 2017;113: 91–9. [262] Eskizeybek V, Avcı A, Gülce A. Preparation and mechanical properties of carbon nanotube grafted glass fabric/epoxy multi-scale composites. Adv Compos Mater 2017;26(2):169–80. [263] Sahraei E, Hill R, Wierzbicki T. Calibration and finite element simulation of pouch lithium-ion batteries for mechanical integrity. J Power Sources 2012;201: 307–21. [264] D.J. O’Brien, D.M. Baechle, E.D. Wetzel, Performance Metrics for Structural Composite Capacitiors, ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, 2010, pp. 215-221. [265] O’Brien DJ, Baechle DM, Wetzel ED. Design and performance of multifunctional structural composite capacitors. J Compos Mater 2011;45(26):2797–809. [266] Snyder JF, Gienger EB, Wetzel ED. Performance metrics for structural composites with electrochemical multifunctionality. J Compos Mater 2015;49(15): 1835–48. [267] Carlstedt D, Asp LE. Performance analysis framework for structural battery composites in electric vehicles. Compos B Eng 2020;186:107822. [268] Pejman R, Gorman J, Najafi AR. Multi-physics design of a new battery packaging for electric vehicles utilizing multifunctional composites. Compos B Eng 2022; 237:109810. [269] Woellert K, Ehrenfreund P, Ricco AJ, Hertzfeld H. Cubesats: Cost-effective science and technology platforms for emerging and developing nations. Adv Space Res 2011;47(4):663–84. [270] CubeSats, NASA, https://www.nasa.gov/mission_pages/cubesats/index.html. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 69 [271] Thomas JP, Qidwai MA. The design and application of multifunctional structure-battery materials systems. JOM 2005;57(3):18–24. [272] Qidwai S, Baucom J, Thomas J, Horner D. Multifunctional Applications of Thin Film Li Polymer Battery Cells. Materials Science Forum - MATER SCI FORUM 2005;492–493:157–62. [273] Riboldi Carlo ED, Trainelli L, Biondani F. Structural Batteries in Aviation: A Preliminary Sizing Methodology. J Aerosp Eng 2020;33(4):04020031. [274] Di Mauro G, Corcione S, Cusati V, Marciello V, Guida M, Nicolosi F. The Potential of Structural Batteries for Commuter Aircraft Hybridization. J Mater Eng Perform 2023;32(9):3871–80. [275] Karadotcheva E, Nguyen SN, Greenhalgh ES, Shaffer MSP, Kucernak ARJ, Linde P. Structural Power Performance Targets for Future Electric Aircraft. Energies 2021. [276] Nguyen SN, Millereux A, Pouyat A, Greenhalgh ES, Shaffer MSP, Kucernak ARJ, et al. Conceptual Multifunctional Design, Feasibility and Requirements for Structural Power in Aircraft Cabins. J Aircr 2021;58(3):677–87. [277] Kim J, Campbell AS, de ´ Avila B-E-F, Wang J. Wearable biosensors for healthcare monitoring. Nat Biotechnol 2019;37(4):389–406. [278] Lim H-R, Kim HS, Qazi R, Kwon Y-T, Jeong J-W, Yeo W-H. Advanced Soft Materials, Sensor Integrations, and Applications of Wearable Flexible Hybrid Electronics in Healthcare, Energy, and Environment. Adv Mater 2020;32(15):1901924. [279] Park J, Lee Y, Cho S, Choe A, Yeom J, Ro YG, et al. Soft Sensors and Actuators for Wearable Human–Machine Interfaces. Chem Rev 2024;124(4):1464–534. [280] Armand M, Tarascon JM. Building better batteries. Nature 2008;451(7179):652–7. [281] Choi K-H, Ahn DB, Lee S-Y. Current Status and Challenges in Printed Batteries: Toward Form Factor-Free. Monolithic Integrated Power Sources, ACS Energy Letters 2018;3(1):220–36. [282] Ahn DB, Lee K-H, Lee S-Y. Printed solid-state electrolytes for form factor-free Li-metal batteries. Curr Opin Electrochem 2022;32:100889. [283] Ahn DB, Lee S-S, Lee K-H, Kim J-H, Lee J-W, Lee S-Y. Form factor-free, printed power sources. Energy Storage Mater 2020;29:92–112. [284] Lyu Z, Lim GJH, Koh JJ, Li Y, Ma Y, Ding J, et al. Design and Manufacture of 3D-Printed Batteries. Joule 2021;5(1):89–114. [285] Lee K-H, Ahn DB, Kim J-H, Lee J-W, Lee S-Y. Printed Built-In Power Sources. Matter 2020;2(2):345–59. [286] Lewis JA. Colloidal Processing of Ceramics. J Am Ceram Soc 2000;83(10):2341–59. [287] Fairhurst D. An Overview of the Zeta Potential Part 3: Uses and Applications. Americal Parmaceutical Review 2013. [288] Kim S-H, Choi K-H, Cho S-J, Yoo J, Lee S-S, Lee S-Y. Flexible/shape-versatile, bipolar all-solid-state lithium-ion batteries prepared by multistage printing. Energ Environ Sci 2018;11(2):321–30. [289] Singh N, Galande C, Miranda A, Mathkar A, Gao W, Reddy ALM, et al. Paintable Battery. Sci Rep 2012;2(1):481. [290] Sun K, Wei T-S, Ahn BY, Seo JY, Dillon SJ, Lewis JA. 3D Printing of Interdigitated Li-Ion Microbattery Architectures. Adv Mater 2013;25(33):4539–43. [291] Sarma Choudhury S, Katiyar N, Saha R, Bhattacharya S. Inkjet-printed flexible planar Zn-MnO2 battery on paper substrate. Sci Rep 2024;14(1):1597. [292] Lee K-H, Lee S-S, Ahn DB, Lee J, Byun D, Lee S-Y. Ultrahigh areal number density solid-state on-chip microsupercapacitors via electrohydrodynamic jet printing. Sci Adv 2020;6(10):eaaz1692. [293] Choi K-H, Kim H-W, Lee S-S, Yoo J, Lee D-G, Lee S-Y. All-Hand-Drawn Zn–Air Batteries: Toward User-Customized On-the-Fly Power Sources. Adv Sustainable Syst 2018;2(5):1700132. [294] Lei Y, Zhao W, Zhu Y, Buttner U, Dong X, Alshareef HN. Three-Dimensional Ti3C2Tx MXene-Prussian Blue Hybrid Microsupercapacitors by Water Lift-Off Lithography. ACS Nano 2022;16(2):1974–85. [295] Liu Z, Wu Z-S, Yang S, Dong R, Feng X, Müllen K. Ultraflexible In-Plane Micro-Supercapacitors by Direct Printing of Solution-Processable Electrochemically Exfoliated Graphene. Adv Mater 2016;28(11):2217–22. [296] Shi X, Wu Z-S, Qin J, Zheng S, Wang S, Zhou F, et al. Graphene-Based Linear Tandem Micro-Supercapacitors with Metal-Free Current Collectors and HighVoltage Output. Adv Mater 2017;29(44):1703034. [297] Kim S-W, Kang K-N, Min J-W, Jang J-H. Plotter-assisted integration of wearable all-solid-state micro-supercapacitors. Nano Energy 2018;50:410–6. [298] Nardekar SS, Krishnamoorthy K, Manoharan S, Pazhamalai P, Kim SJ. Two Faces Under a Hood: Unravelling the Energy Harnessing and Storage Properties of 1T-MoS2 Quantum Sheets for Next-Generation Stand-Alone Energy Systems. ACS Nano 2022;16(3):3723–34. [299] Kim S-W, Lee K-H, Lee Y-H, Youe W-J, Gwon J-G, Lee S-Y. Transparent and Multi-Foldable Nanocellulose Paper Microsupercapacitors. Adv Sci 2022;9(34): 2203720. [300] Li J, Shi Q, Shao Y, Hou C, Li Y, Zhang Q, et al. Cladding nanostructured AgNWs-MoS2 electrode material for high-rate and long-life transparent in-plane micro-supercapacitor. Energy Storage Mater 2019;16:212–9. [301] Li C, Bu F, Wang Q, Liu X. Recent Developments of Inkjet-Printed Flexible Energy Storage Devices. Adv Mater Interfaces 2022;9(34):2201051. [302] Wei T-S, Ahn BY, Grotto J, Lewis JA. 3D Printing of Customized Li-Ion Batteries with Thick Electrodes. Adv Mater 2018;30(16):1703027. [303] Cao D, Xing Y, Tantratian K, Wang X, Ma Y, Mukhopadhyay A, et al. 3D Printed High-Performance Lithium Metal Microbatteries Enabled by Nanocellulose. Adv Mater 2019;31(14):1807313. [304] Lacey SD, Kirsch DJ, Li Y, Morgenstern JT, Zarket BC, Yao Y, et al. Extrusion-Based 3D Printing of Hierarchically Porous Advanced Battery Electrodes. Adv Mater 2018;30(12):1705651. [305] Kim S-H, Kim J-H, Cho S-J, Lee S-Y. All-Solid-State Printed Bipolar Li–S Batteries. Adv Energy Mater 2019;9(40):1901841. [306] Ma J, Zheng S, Chi L, Liu Y, Zhang Y, Wang K, et al. 3D Printing Flexible Sodium-Ion Microbatteries with Ultrahigh Areal Capacity and Robust Rate Capability. Adv Mater 2022;34(39):2205569. [307] Ahn DB, Kim W-Y, Lee K-H, Lee S-S, Kim S-H, Park S, et al. Enabling On-Demand Conformal Zn-Ion Batteries on Non-Developable Surfaces. Adv Funct Mater 2023;33(18):2211597. [308] Shi G, Peng X, Zeng J, Zhong L, Sun Y, Yang W, et al. A Liquid Metal Microdroplets Initialized Hemicellulose Composite for 3D Printing Anode Host in Zn-Ion Battery. Adv Mater 2023;35(25):2300109. [309] Choi K-H, Yoo J, Lee CK, Lee S-Y. All-inkjet-printed, solid-state flexible supercapacitors on paper. Energ Environ Sci 2016;9(9):2812–21. [310] Tang X, Zhou H, Cai Z, Cheng D, He P, Xie P, et al. Generalized 3D Printing of Graphene-Based Mixed-Dimensional Hybrid Aerogels. ACS Nano 2018;12(4): 3502–11. [311] Shen K, Ding J, Yang S. 3D Printing Quasi-Solid-State Asymmetric Micro-Supercapacitors with Ultrahigh Areal Energy Density. Adv Energy Mater 2018;8(20): 1800408. [312] Gao T, Zhou Z, Yu J, Zhao J, Wang G, Cao D, et al. 3D Printing of Tunable Energy Storage Devices with Both High Areal and Volumetric Energy Densities. Adv Energy Mater 2019;9(8):1802578. [313] Zhang C, McKeon L, Kremer MP, Park S-H, Ronan O, Seral-Ascaso A, et al. Additive-free MXene inks and direct printing of micro-supercapacitors. Nat Commun 2019;10(1):1795. [314] Fan Z, Wei C, Yu L, Xia Z, Cai J, Tian Z, et al. 3D Printing of Porous Nitrogen-Doped Ti3C2 MXene Scaffolds for High-Performance Sodium-Ion Hybrid Capacitors. ACS Nano 2020;14(1):867–76. [315] Wang Z, Lee Y-H, Kim S-W, Seo J-Y, Lee S-Y, Nyholm L. Why Cellulose-Based Electrochemical Energy Storage Devices? Adv Mater 2021;33(28):2000892. [316] Fu K, Wang Y, Yan C, Yao Y, Chen Y, Dai J, et al. Graphene Oxide-Based Electrode Inks for 3D-Printed Lithium-Ion Batteries. Adv Mater 2016;28(13):2587–94. [317] Tagliaferri S, Nagaraju G, Panagiotopoulos A, Och M, Cheng G, Iacoviello F, et al. Aqueous Inks of Pristine Graphene for 3D Printed Microsupercapacitors with High Capacitance. ACS Nano 2021;15(9):15342–53. [318] Kim S-H, Choi K-H, Cho S-J, Choi S, Park S, Lee S-Y. Printable Solid-State Lithium-Ion Batteries: A New Route toward Shape-Conformable Power Sources with Aesthetic Versatility for Flexible Electronics. Nano Lett 2015;15(8):5168–77. [319] Hwang J-Y, Myung S-T, Sun Y-K. Sodium-ion batteries: present and future. Chem Soc Rev 2017;46(12):3529–614. [320] Delmas C. Sodium and Sodium-Ion Batteries: 50 Years of Research. Adv Energy Mater 2018;8(17):1703137. [321] Yabuuchi N, Kubota K, Dahbi M, Komaba S. Research Development on Sodium-Ion Batteries. Chem Rev 2014;114(23):11636–82. [322] Tang B, Shan L, Liang S, Zhou J. Issues and opportunities facing aqueous zinc-ion batteries. Energ Environ Sci 2019;12(11):3288–304. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 70 [323] Fang G, Zhou J, Pan A, Liang S. Recent Advances in Aqueous Zinc-Ion Batteries. ACS Energy Lett 2018;3(10):2480–501. [324] Kang H, Kim S-H, Ahn DB, Wang X, Wu Z-S, Lee S-Y. Liquid Metal-Skinned Zn Powder Anodes Enabled by Capillary Suspension. ACS Energy Lett 2024;9(6): 2816–25. [325] Lee S-S, Choi K-H, Kim S-H, Lee S-Y. Wearable Supercapacitors Printed on Garments. Adv Funct Mater 2018;28(11):1705571. [326] Yun Y, Nandanapalli KR, Choi J-H, Son W, Choi C, Lee S. Extremely flexible and mechanically durable planar supercapacitors: High energy density and lowcost power source for E-skin electronics. Nano Energy 2020;78:105356. [327] Lee K-H, Jeon J, Cho W, Kim S-W, Moon H, Wie JJ, et al. Light-triggered autonomous shape-reconfigurable and locomotive rechargeable power sources. Mater Today 2022;55:56–65. [328] Wang S, Liu N, Tao J, Yang C, Liu W, Shi Y, et al. Inkjet printing of conductive patterns and supercapacitors using a multi-walled carbon nanotube/Ag nanoparticle based ink. J Mater Chem A 2015;3(5):2407–13. [329] Hu L, Wu H, Cui Y. Printed energy storage devices by integration of electrodes and separators into single sheets of paper. Appl Phys Lett 2010;96(18). [330] Lee K-H, Kim S-W, Kim M, Ahn DB, Hong Y-K, Kim S-H, et al. Folding the Energy Storage: Beyond the Limit of Areal Energy Density of Micro-Supercapacitors. Adv Energy Mater 2023;13(20):2204327. [331] Jiang Y, Xu Z, Huang T, Liu Y, Guo F, Xi J, et al. Direct 3D Printing of Ultralight Graphene Oxide Aerogel Microlattices. Adv Funct Mater 2018;28(16):1707024. [332] Wang Z, Zhang QE, Long S, Luo Y, Yu P, Tan Z, Bai J, Qu B, Yang Y, Shi J, Zhou H, Xiao Z-Y, Hong W, Bai H. Three-Dimensional Printing of Polyaniline/ Reduced Graphene Oxide Composite for High-Performance Planar Supercapacitor. ACS Appl Mater Interfaces 2018;10(12):10437–44. [333] Yao B, Chandrasekaran S, Zhang J, Xiao W, Qian F, Zhu C, et al. Efficient 3D Printed Pseudocapacitive Electrodes with Ultrahigh MnO2 Loading. Joule 2019;3 (2):459–70. [334] Tang X, Zhu C, Cheng D, Zhou H, Liu X, Xie P, et al. Architectured Leaf-Inspired Ni0.33Co0.66S2/Graphene Aerogels via 3D Printing for High-Performance Energy Storage. Adv Funct Mater 2018;28(51):1805057. [335] Yang W, Yang J, Byun JJ, Moissinac FP, Xu J, Haigh SJ, et al. 3D Printing of Freestanding MXene Architectures for Current-Collector-Free Supercapacitors. Adv Mater 2019;31(37):1902725. [336] Zhang C, Kremer MP, Seral-Ascaso A, Park S-H, McEvoy N, Anasori B, et al. Stamping of Flexible, Coplanar Micro-Supercapacitors Using MXene Inks. Adv Funct Mater 2018;28(9):1705506. [337] Banerjee A, Wang X, Fang C, Wu EA, Meng YS. Interfaces and Interphases in All-Solid-State Batteries with Inorganic Solid Electrolytes. Chem Rev 2020;120 (14):6878–933. [338] Zhao Q, Stalin S, Zhao C-Z, Archer LA. Designing solid-state electrolytes for safe, energy-dense batteries. Nat Rev Mater 2020;5(3):229–52. [339] McOwen DW, Xu S, Gong Y, Wen Y, Godbey GL, Gritton JE, et al. 3D-Printing Electrolytes for Solid-State Batteries. Adv Mater 2018;30(18):1707132. [340] Ping W, Wang C, Wang R, Dong Q, Lin Z, Brozena AH, et al. Printable, high-performance solid-state electrolyte films. Sci Adv 2020;6(47):eabc8641. [341] Nam YJ, Cho S-J, Oh DY, Lim J-M, Kim SY, Song JH, et al. Bendable and Thin Sulfide Solid Electrolyte Film: A New Electrolyte Opportunity for Free-Standing and Stackable High-Energy All-Solid-State Lithium-Ion Batteries. Nano Lett 2015;15(5):3317–23. [342] Lee S-S, Kim S-H, Ahn DB, Lee K-H, Jo Y, Jeong S, et al. All-Direct-Ink-Writing of Artistic Supercapacitors: Toward On-Demand Embodied Power Sources. Adv Funct Mater 2022;32(34):2202901. [343] He Y, Chen S, Nie L, Sun Z, Wu X, Liu W. Stereolithography Three-Dimensional Printing Solid Polymer Electrolytes for All-Solid-State Lithium Metal Batteries. Nano Lett 2020;20(10):7136–43. [344] Oh K-S, Kim J-H, Kim S-H, Oh D, Han S-P, Jung K, et al. Single-Ion Conducting Soft Electrolytes for Semi-Solid Lithium Metal Batteries Enabling Cell Fabrication and Operation under Ambient Conditions. Adv Energy Mater 2021;11(38):2101813. [345] Chae C, Han JH, Lee SS, Choi Y, Kim T-H, Jeong S. A Printable Metallic Current Collector for All-Printed High-Voltage Micro-Supercapacitors: Instantaneous Surface Passivation by Flash-Light-Sintering Reaction. Adv Funct Mater 2020;30(25):2000715. [346] Jo Y, Park HJ, Kim Y-B, Lee SS, Lee SY, Kim S-K, et al. Form-Factor Free 3D Copper Circuits by Surface-Conformal Direct Printing and Laser Writing. Adv Funct Mater 2020;30(45):2004659. [347] Owens CE, Headrick RJ, Williams SM, Fike AJ, Pasquali M, McKinley GH, et al. Substrate-Versatile Direct-Write Printing of Carbon Nanotube-Based Flexible Conductors, Circuits, and Sensors. Adv Funct Mater 2021;31(25):2100245. [348] Manthiram A, Yu X, Wang S. Lithium battery chemistries enabled by solid-state electrolytes. Nat Rev Mater 2017;2(4):16103. [349] Lee Y-G, Fujiki S, Jung C, Suzuki N, Yashiro N, Omoda R, et al. High-energy long-cycling all-solid-state lithium metal batteries enabled by silver–carbon composite anodes. Nat Energy 2020;5(4):299–308. [350] Kil E-H, Choi K-H, Ha H-J, Xu S, Rogers JA, Kim MR, et al. Imprintable, Bendable, and Shape-Conformable Polymer Electrolytes for Versatile-Shaped LithiumIon Batteries. Adv Mater 2013;25(10):1395–400. [351] Choi K-H, Kim S-H, Ha H-J, Kil E-H, Lee CK, Lee SB, et al. Compliant polymer network-mediated fabrication of a bendable plastic crystal polymer electrolyte for flexible lithium-ion batteries. J Mater Chem A 2013;1(17):5224–31. [352] Kwon YW, Ahn DB, Park Y-G, Kim E, Lee DH, Kim S-W, et al. Power-integrated, wireless neural recording systems on the cranium using a direct printing method for deep-brain analysis. Sci Adv 2024;10(14):eadn3784. [353] Sun P, Li X, Shao J, Braun PV. High-Performance Packaged 3D Lithium-Ion Microbatteries Fabricated Using Imprint Lithography. Adv Mater 2021;33(1): 2006229. [354] Wang S, Li L, Zheng S, Das P, Shi X, Ma J, et al. Monolithic integrated micro-supercapacitors with ultra-high systemic volumetric performance and areal output voltage. Natl Sci Rev 2022;10(3). [355] Bae J, Oh S, Lee B, Lee CH, Chung J, Kim J, et al. High-performance, printable quasi-solid-state electrolytes toward all 3D direct ink writing of shape-versatile Li-ion batteries. Energy Storage Mater 2023;57:277–88. [356] Shao Y, Wei L, Wu X, Jiang C, Yao Y, Peng B, et al. Room-temperature high-precision printing of flexible wireless electronics based on MXene inks. Nat Commun 2022;13(1):3223. [357] Park J, Ahn DB, Kim J, Cha E, Bae B-S, Lee S-Y, et al. Printing of wirelessly rechargeable solid-state supercapacitors for soft, smart contact lenses with continuous operations. Sci Adv 2019;5(12):eaay0764. [358] Kim J-H, Hwang I, Kim S-H, Park J, Jin W, Seo K, et al. Voltage-tunable portable power supplies based on tailored integration of modularized silicon photovoltaics and printed bipolar lithium-ion batteries. J Mater Chem A 2020;8(32):16291–301. [359] Yin L, Cao M, Kim KN, Lin M, Moon J-M, Sempionatto JR, et al. A stretchable epidermal sweat sensing platform with an integrated printed battery and electrochromic display. Nat Electron 2022;5(10):694–705. [360] Ryou M-H, Kim S-H, Kim S-W, Lee S-Y. A microgrid-patterned silicon electrode as an electroactive lithium host. Energ Environ Sci 2022;15(6):2581–90. [361] Lim GJH, Lyu Z, Zhang X, Koh JJ, Zhang Y, He C, et al. Robust pure copper framework by extrusion 3D printing for advanced lithium metal anodes. J Mater Chem A 2020;8(18):9058–67. [362] Park S, Shi B, Shang Y, Deng K, Fu K. Structured Electrode Additive Manufacturing for Lithium-Ion Batteries. Nano Lett 2022;22(23):9462–9. [363] Park S, Cao Z, Sung DH, Fu KK. High-Loaded Electrode Filaments for Additive Manufacturing of Structural Batteries. Adv Energy Mater 2023;13(38):2301704. [364] Lee K-H, Lee S-Y. Cell architecture designs towards high-energy-density microscale energy storage devices. Nano Research Energy 2024;3:e9120101. [365] Gao Y, Guo Q, Zhang Q, Cui Y, Zheng Z. Fibrous Materials for Flexible Li–S Battery. Adv Energy Mater 2021;11(15):2002580. [366] Kong L, Tang C, Peng H-J, Huang J-Q, Zhang Q. Advanced energy materials for flexible batteries in energy storage: A review. SmartMat 2020;1(1):1–35. [367] Shi Q, Dong B, He T, Sun Z, Zhu J, Zhang Z, et al. Progress in wearable electronics/photonics—Moving toward the era of artificial intelligence and internet of things. InfoMat 2020;2(6):1131–62. [368] Choi JW, Aurbach D. Promise and reality of post-lithium-ion batteries with high energy densities. Nat Rev Mater 2016;1(4):16013. [369] Zhang X, Cheng X, Zhang Q. Nanostructured energy materials for electrochemical energy conversion and storage: A review. Journal of Energy Chemistry 2016; 25(6):967–84. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 71 [370] Xu C, Niu Y, Ka-Man Au V, Gong S, Liu X, Wang J, et al. Recent progress of self-supported air electrodes for flexible Zn-air batteries. Journal of Energy Chemistry 2024;89:110–36. [371] Jia SK, Yang BZ, Zhao CF, Zhang ZY, Yin YH, Liu XB, et al. Tab engineering-mediated resistance of flexible lithium-ion batteries for high output current. Journal of Energy Chemistry 2021;58:264–70. [372] Wang Y, Zhu J, Chen A, Guo X, Cui H, Chen Z, et al. Spider Silk-Inspired Binder Design for Flexible Lithium-Ion Battery with High Durability. Adv Mater 2023; 35(47):2303165. [373] Nishide H, Oyaizu K. Toward Flexible Batteries. Science 2008;319(5864):737–8. [374] Peng J, Snyder GJ. A figure of merit for flexibility. Science 2019;366(6466):690–1. [375] Ashby MF. The deformation of plastically non-homogeneous materials, The Philosophical Magazine: A Journal of Theoretical Experimental and Applied. Physics 1970;21(170):399–424. [376] Kong L, Peng H-J, Huang J-Q, Zhang Q. Review of nanostructured current collectors in lithium–sulfur batteries. Nano Res 2017;10(12):4027–54. [377] Ye Y, Chou L-Y, Liu Y, Wang H, Lee HK, Huang W, et al. Ultralight and fire-extinguishing current collectors for high-energy and high-safety lithium-ion batteries. Nat Energy 2020;5(10):786–93. [378] Yang W, Yang W, Zeng J, Chen Y, Huang Y, Liu J, et al. Biopolymer-based gel electrolytes for electrochemical energy Storage: Advances and prospects. Prog Mater Sci 2024;144:101264. [379] Li X, Wang D, Ran F. Key approaches and challenges in fabricating advanced flexible zinc-ion batteries with functional hydrogel electrolytes. Energy Storage Mater 2023;56:351–93. [380] Deimede V, Elmasides C. Separators for Lithium-Ion Batteries: A Review on the Production Processes and Recent Developments. Energ Technol 2015;3(5): 453–68. [381] Zhuang T-Z, Huang J-Q, Peng H-J, He L-Y, Cheng X-B, Chen C-M, et al. Rational Integration of Polypropylene/Graphene Oxide/Nafion as Ternary-Layered Separator to Retard the Shuttle of Polysulfides for Lithium–Sulfur Batteries. Small 2016;12(3):381–9. [382] Li B-Q, Zhang S-Y, Wang B, Xia Z-J, Tang C, Zhang Q. A porphyrin covalent organic framework cathode for flexible Zn–air batteries. Energ Environ Sci 2018;11 (7):1723–9. [383] Wang H-F, Tang C, Wang B, Li B-Q, Cui X, Zhang Q. Defect-rich carbon fiber electrocatalysts with porous graphene skin for flexible solid-state zinc–air batteries. Energy Storage Mater 2018;15:124–30. [384] Peng H-J, Huang J-Q, Zhang Q. A review of flexible lithium–sulfur and analogous alkali metal–chalcogen rechargeable batteries. Chem Soc Rev 2017;46(17): 5237–88. [385] Jin J, Cai W, Cai J, Shao Y, Song Y, Xia Z, et al. MOF-derived hierarchical CoP nanoflakes anchored on vertically erected graphene scaffolds as self-supported and flexible hosts for lithium–sulfur batteries. J Mater Chem A 2020;8(6):3027–34. [386] Li H, Tang Z, Liu Z, Zhi C. Evaluating Flexibility and Wearability of Flexible Energy Storage Devices. Joule 2019;3(3):613–9. [387] Song Z, Ma T, Tang R, Cheng Q, Wang X, Krishnaraju D, et al. Origami lithium-ion batteries. Nat Commun 2014;5(1):3140. [388] Song Z, Wang X, Lv C, An Y, Liang M, Ma T, et al. Kirigami-based stretchable lithium-ion batteries. Sci Rep 2015;5(1):10988. [389] Liu W, Chen J, Chen Z, Liu K, Zhou G, Sun Y, et al. Stretchable Lithium-Ion Batteries Enabled by Device-Scaled Wavy Structure and Elastic-Sticky Separator. Adv Energy Mater 2017;7(21):1701076. [390] Shi C, Wang T, Liao X, Qie B, Yang P, Chen M, et al. Accordion-like stretchable Li-ion batteries with high energy density. Energy Storage Mater 2019;17: 136–42. [391] Chen X, Liu B, Zhong C, Liu Z, Liu J, Ma L, et al. Ultrathin Co3O4 Layers with Large Contact Area on Carbon Fibers as High-Performance Electrode for Flexible Zinc–Air Battery Integrated with Flexible Display. Adv Energy Mater 2017;7(18):1700779. [392] Zhu Y-H, Yang X-Y, Liu T, Zhang X-B. Flexible 1D Batteries: Recent Progress and Prospects. Adv Mater 2020;32(5):1901961. [393] Liao M, Wang C, Hong Y, Zhang Y, Cheng X, Sun H, et al. Industrial scale production of fibre batteries by a solution-extrusion method. Nat Nanotechnol 2022; 17(4):372–7. [394] Xi Z, Zhang X, Ma Y, Zhou C, Yang J, Wu Y, et al. Recent Progress in Flexible Fibrous Batteries. ChemElectroChem 2018;5(21):3127–37. [395] Wang L, Chen D, Jiang K, Shen G. New insights and perspectives into biological materials for flexible electronics. Chem Soc Rev 2017;46(22):6764–815. [396] Juqu T, Willenberg SC, Pokpas K, Ross N. Advances in paper-based battery research for biodegradable energy storage. Adv Sens Energy Mater 2022;1(4): 100037. [397] Senthilkumar ST, Abirami M, Kim J, Go W, Hwang SM, Kim Y. Sodium-ion hybrid electrolyte battery for sustainable energy storage applications. J Power Sources 2017;341:404–10. [398] Ani PC, Nzereogu PU, Agbogu AC, Ezema FI, Nwanya AC. Cellulose from waste materials for electrochemical energy storage applications: A review. Appl Surf Sci Adv 2022;11:100298. [399] Wu M, Zhang Y, Xu L, Yang C, Hong M, Cui M, et al. A sustainable chitosan-zinc electrolyte for high-rate zinc-metal batteries. Matter 2022;5(10):3402–16. [400] Ali AMM, Subban RHY, Bahron H, Yahya MZA, Kamisan AS. Investigation on modified natural rubber gel polymer electrolytes for lithium polymer battery. J Power Sources 2013;244:636–40. [401] Abraham KM. How Comparable Are Sodium-Ion Batteries to Lithium-Ion Counterparts? ACS Energy Lett 2020;5(11):3544–7. [402] Col` o F, Bella F, Nair JR, Destro M, Gerbaldi C. Cellulose-based novel hybrid polymer electrolytes for green and efficient Na-ion batteries. Electrochim Acta 2015;174:185–90. [403] Chen HY, Keller A, Conn AT, Rossiter J. GelBat: An Edible Gelatin-Based Battery. IEEE International Conference on Soft Robotics (RoboSoft) 2023;2023:1–6. [404] Gouda A, Masson A, Hoseinizadeh M, Soavi F, Santato C. Biosourced quinones for high-performance environmentally benign electrochemical capacitors via interface engineering. Communications Chemistry 2022;5(1):98. [405] Rahmanudin A, Mohammadi M, Isacsson P, Li Y, Seufert L, Kim N, et al. Stretchable and biodegradable plant-based redox-diffusion batteries. Mater Horiz 2024;11(18):4400–12. [406] Sun L, Yao Y, Dai L, Jiao M, Ding B, Yu Q, et al. Sustainable and high-performance Zn dual-ion batteries with a hydrogel-based water-in-salt electrolyte. Energy Storage Mater 2022;47:187–94. [407] Leong KW, Pan W, Yi X, Luo S, Zhao X, Zhang Y, et al. Next-generation magnesium-ion batteries: The quasi-solid-state approach to multivalent metal ion storage. Sci Adv 2023;9(32):eadh1181. [408] Tsang M, Armutlulu A, Martinez AW, Allen SAB, Allen MG. Biodegradable magnesium/iron batteries with polycaprolactone encapsulation: A microfabricated power source for transient implantable devices. Microsyst Nanoeng 2015;1(1):15024. [409] Mei T, Wang C, Liao M, Li J, Wang L, Tang C, et al. A biodegradable and rechargeable fiber battery. J Mater Chem A 2021;9(16):10104–9. [410] Luo P, Zheng C, He J, Tu X, Sun W, Pan H, et al. Structural Engineering in Graphite-Based Metal-Ion Batteries. Adv Funct Mater 2022;32(9):2107277. [411] Noh SH, Kwon C, Hwang J, Ohsaka T, Kim B-J, Kim T-Y, et al. Self-assembled nitrogen-doped fullerenes and their catalysis for fuel cell and rechargeable metal–air battery applications. Nanoscale 2017;9(22):7373–9. [412] Jiang Z, Zhao Y, Lu X, Xie J. Fullerenes for rechargeable battery applications: Recent developments and future perspectives. Journal of Energy Chemistry 2021; 55:70–9. [413] Zhu S, Sheng J, Chen Y, Ni J, Li Y. Carbon nanotubes for flexible batteries: recent progress and future perspective. Natl Sci Rev 2020;8(5). [414] Ning J, Jiang T, Men K, Dai Q, Li D, Wei Y, et al. Syntheses, Characterizations, and Applications in Lithium Ion Batteries of Hierarchical SnO Nanocrystals. J Phys Chem C 2009;113(32):14140–4. [415] Muraliganth T, Vadivel Murugan A, Manthiram A. Facile synthesis of carbon-decorated single-crystalline Fe3O4nanowires and their application as high performance anode in lithium ion batteries. Chemical Communications (47) 2009:7360–2. [416] Yao B, Zhang J, Kou T, Song Y, Liu T, Li Y. Paper-Based Electrodes for Flexible Energy Storage Devices. Adv Sci 2017;4(7):1700107. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 72 [417] Sampaio PGV, Gonz´ alez MOA, de Oliveira Ferreira P, da Cunha J´ acome P, Vidal JPP, Pereira HR, et al. Overview of printing and coating techniques in the production of organic photovoltaic cells. Int J Energy Res 2020;44(13):9912–31. [418] R. Szentgy¨ orgyv¨ olgyi, E. Novotny, M. Weimert, DETERMINING AND SELECTING SCREEN PRINTING FORM PARAMETERS FOR PRINTING ON PAPER AND TEXTILE, 2018. [419] A. C, Łuszczy´ nska B, Dupont B, Sieradzki Z. Inkjet Printing Technique and Its Application in Organic Light Emitting Diodes †. Display and Imaging 2017;2: 339–58. [420] Wang Y, Pan W, Kwok HYH, Zhang H, Lu X, Leung DYC. Liquid-free Al-air batteries with paper-based gel electrolyte: A green energy technology for portable electronics. J Power Sources 2019;437:226896. [421] Navarro-Segarra M, Tortosa C, Ruiz-Díez C, Desma¨ ele D, Gea T, Barrena R, et al. A plant-like battery: a biodegradable power source ecodesigned for precision agriculture. Energ Environ Sci 2022;15(7):2900–15. [422] Edstr¨ om K, Brandell D, Gustafsson T, Nyholm L. Electrodeposition as a Tool for 3D Microbattery Fabrication. The Electrochemical Society Interface 2011;20 (2):41. [423] Jones SD, Akridge JR, Shokoohi FK. Thin film rechargeable Li batteries. Solid State Ion 1994;69(3):357–68. [424] Jones SD, Akridge JR. A thin-film solid-state microbattery. J Power Sources 1993;44(1):505–13. [425] West WC, Whitacre JF, White V, Ratnakumar BV. Fabrication and testing of all solid-state microscale lithium batteries for microspacecraft applications. J Micromech Microeng 2002;12(1):58. [426] J.B. Bates, N.J. Dudney, G.R. Gruzalski, C.F. Luck, Thin film battery and method for making same, 1994. [427] Bates JB, Gruzalski GR, Luck CF. Rechargeable solid state lithium microbatteries. Proceedings IEEE Micro Electro Mechanical Systems 1993;1993:82–6. [428] Bates JB, Dudney NJ, Gruzalski GR, Zuhr RA, Choudhury A, Luck CF, et al. Fabrication and characterization of amorphous lithium electrolyte thin films and rechargeable thin-film batteries. J Power Sources 1993;43(1):103–10. [429] Bates JB, Dudney NJ, Lubben DC, Gruzalski GR, Kwak BS, Yu X, et al. Thin-film rechargeable lithium batteries. J Power Sources 1995;54(1):58–62. [430] Neudecker BJ, Dudney NJ, Bates JB. “Lithium-Free” Thin-Film Battery with In Situ Plated Li Anode. J Electrochem Soc 2000;147(2):517. [431] Wenzel S, Randau S, Leichtweiß T, Weber DA, Sann J, Zeier WG, et al. Direct Observation of the Interfacial Instability of the Fast Ionic Conductor Li10GeP2S12 at the Lithium Metal Anode. Chem Mater 2016;28(7):2400–7. [432] Yoon K, Kim J-J, Seong WM, Lee MH, Kang K. Investigation on the interface between Li10GeP2S12 electrolyte and carbon conductive agents in all-solid-state lithium battery. Sci Rep 2018;8(1):8066. [433] Murugan R, Thangadurai V, Weppner W. Fast Lithium Ion Conduction in Garnet-Type Li7La3Zr2O12. Angew Chem Int Ed 2007;46(41):7778–81. [434] Liu X, Garcia-Mendez R, Lupini AR, Cheng Y, Hood ZD, Han F, et al. Local electronic structure variation resulting in Li ‘filament’ formation within solid electrolytes. Nat Mater 2021;20(11):1485–90. [435] Jiang Z, Han Q, Wang S, Wang H. Reducing the Interfacial Resistance in All-Solid-State Lithium Batteries Based on Oxide Ceramic Electrolytes. ChemElectroChem 2019;6(12):2970–83. [436] Hart RW, White HS, Dunn B, Rolison DR. 3-D Microbatteries. Electrochem Commun 2003;5(2):120–3. [437] Long JW, Dunn B, Rolison DR, White HS. Three-Dimensional Battery Architectures. Chem Rev 2004;104(10):4463–92. [438] Enerchip, Enerchip CBC050 datasheet DS-72-01 Rev10 www.Cymbet.com 2009., 2009. [439] Patrissi CJ, Martin CR. Sol-Gel-Based Template Synthesis and Li-Insertion Rate Performance of Nanostructured Vanadium Pentoxide. J Electrochem Soc 1999; 146(9):3176. [440] Sides CR, Martin CR. Nanostructured Electrodes and the Low-Temperature Performance of Li-Ion Batteries. Adv Mater 2005;17(1):125–8. [441] Ortiz GF, Hanzu I, Djenizian T, Lavela P, Tirado JL, Knauth P. Alternative Li-Ion Battery Electrode Based on Self-Organized Titania Nanotubes. Chem Mater 2009;21(1):63–7. [442] Roberts M, Johns P, Owen J, Brandell D, Edstrom K, El Enany G, et al. 3D lithium ion batteries—from fundamentals to fabrication. J Mater Chem 2011;21(27): 9876–90. [443] Wang C, Taherabadi L, Jia G, Madou M, Yeh Y, Dunn B. C-MEMS for the Manufacture of 3D Microbatteries. Electrochem Solid St 2004;7(11):A435. [444] Hasan M, Chowdhury T, Rohan JF. Nanotubes of Core/Shell Cu / Cu2O as Anode Materials for Li-Ion Rechargeable Batteries. J Electrochem Soc 2010;157(6): A682. [445] Perre E, Taberna PL, Mazouzi D, Poizot P, Gustafsson T, Edstr¨ om K, et al. Electrodeposited Cu2Sb as anode material for 3-dimensional Li-ion microbatteries. J Mater Res 2010;25(8):1485–91. [446] Vullum F, Teeters D. Investigation of lithium battery nanoelectrode arrays and their component nanobatteries. J Power Sources 2005;146(1):804–8. [447] Nathan M, Golodnitsky D, Yufit V, Strauss E, Ripenbein T, Shechtman I, et al. Three-dimensional thin-film Li-ion microbatteries for autonomous MEMS. J Microelectromech Syst 2005;14(5):879–85. [448] Notten PHL, Roozeboom F, Niessen RAH, Baggetto L. 3-D Integrated All-Solid-State Rechargeable Batteries. Adv Mater 2007;19(24):4564–7. [449] Baggetto L, Niessen RAH, Roozeboom F, Notten PHL. High Energy Density All-Solid-State Batteries: A Challenging Concept Towards 3D Integration. Adv Funct Mater 2008;18(7):1057–66. [450] A.V. Jeyaseelan, J.F. Rohan, Fabrication of three-dimensional substrates for Li microbatteries on Si, Applied Surface Science 256(3, Supplement) (2009) S61S64. [451] Chamran F, Yeh Y, Min HS, Dunn B, Kim CJ. Fabrication of High-Aspect-Ratio Electrode Arrays for Three-Dimensional Microbatteries. J Microelectromech Syst 2007;16(4):844–52. [452] Pikul JH, Gang Zhang H, Cho J, Braun PV, King WP. High-power lithium ion microbatteries from interdigitated three-dimensional bicontinuous nanoporous electrodes. Nat Commun 2013;4(1):1732. [453] Ning H, Pikul JH, Zhang R, Li X, Xu S, Wang J, et al. Holographic patterning of high-performance on-chip 3D lithium-ion microbatteries. Proc Natl Acad Sci 2015;112(21):6573–8. [454] Behboudikhiavi S, Omale JO, Babu B, Piraux L, Vlad A. Electrodeposition of Li-Ion Cathode Materials: The Fascinating Alternative for Li-Ion Micro-Batteries Fabrication. J Electrochem Soc 2023;170(2):020509. [455] Zhang H, Ning H, Busbee J, Shen Z, Kiggins C, Hua Y, et al. Electroplating lithium transition metal oxides. Sci Adv 2017;3(5):e1602427. [456] Johns P, Roberts M, Owen J. Conformal electrodeposition of manganese dioxide onto reticulated vitreous carbon for 3D microbattery applications. J Mater Chem 2011;21(27):10153–9. [457] Armstrong E, McNulty D, Geaney H, O’Dwyer C. Electrodeposited Structurally Stable V2O5 Inverse Opal Networks as High Performance Thin Film Lithium Batteries. ACS Appl Mater Interfaces 2015;7(48):27006–15. [458] Chen Y, Tarascon J-M, Gu´ ery C. Electrochemically assisted growth of LiFePO4 in ionic liquid media. Electrochem Commun 2011;13(7):673–6. [459] Yufit V, Freedman K, Nathan M, Burstein L, Golodnitsky D, Peled E. Thin-film iron sulfide cathodes for lithium and Li-ion/polymer electrolyte microbatteries. Electrochim Acta 2004;50(2):417–20. [460] McGrath LM, Rohan JF. High-Rate Lithium-Ion Cycling in Electrodeposited Binder-Free Thin-Film Vanadium Oxide Cathodes with Lithium Metal Anodes in Ionic Liquid and Polymer Gel Analogue Electrolytes. Batteries Supercaps 2021;4(3):485–92. [461] Egorov V, Gulzar U, Zhang Y, Breen S, O’Dwyer C. Evolution of 3D Printing Methods and Materials for Electrochemical Energy Storage. Adv Mater 2020;32 (29):2000556. [462] Teranishi T, Yoshikawa Y, Yoneda M, Kishimoto A, Halpin J, O’Brien S, et al. Aluminum Interdiffusion into LiCoO2 Using Atomic Layer Deposition for High Rate Lithium Ion Batteries. ACS Appl Energy Mater 2018;1(7):3277–82. [463] Janek J, Zeier WG. A solid future for battery development. Nat Energy 2016;1(9):16141. [464] Zhu Y, He X, Mo Y. First principles study on electrochemical and chemical stability of solid electrolyte–electrode interfaces in all-solid-state Li-ion batteries. J Mater Chem A 2016;4(9):3253–66. C.M. Costa et al. Progress in Materials Science 154 (2025) 101506 73