ARTICLE OPEN
Flexible aqueous Zn–S ba e y based on an S-deco a ed
Ti
3
C
2
T
x
ca hode
Ke al K. Soniga a
1
, Jay aj V. Vaghasiya
2
, Ca men C. Mayo ga-Ma inez
2
and Ma in Pume a
1,2,3,4
✉
Flexible aqueous zinc-ion ba e ies can s o e ene gy sa ely and a a low cos , which benefi s wea able elec onic gadge s; howe e ,
cu en ly used ca hodes es ic hese de ices wi h a low specific capaci y and ene gy densi y. He ein, we de eloped a flexible zinc-
sul u (Zn–S) ba e y cons uc ed by Ti
3
C
2
T
x
deco a ed wi h sul u (S@Ti
3
C
2
T
x
) as a ca hode and Zn me al anode wi h iodine-added
amphiphilic gel elec oly e (AGE). Benefi ing om he confinemen syne gy o S@Ti
3
C
2
T
x
ca hode, he Zn-S ba e y exhibi ed a high
s o age capaci y o 772.7 mAh g
−1
a 300 mA g
−1
, which is highe han a con en ional S-deco a ed ca bon ca hode
(491.7 mAh g
−1
). Mo e specially, he flexible de ice o e s good cycling s abili y (82.7%) and excellen mechanical s abili y wi h 91%
capaci y e en ion a e 90° bending (500 cycles). To demons a e eal applica ions, he flexible Zn–S ba e ies we e in eg a ed in
se ies o powe elec ical gadge s (e.g., digi al clock, ligh -emi ing diode, and obo ). I exhibi s excep ional flexibili y o sus ain
di e en de o ma ions and main ains a s eady supply o powe o un he wea able elec onic gadge . These findings o e a esh
s a ing poin o flexible ene gy s o age echnologies and show he p omising po en ial o he Zn–S ba e y in eal-wo ld
applica ions.
npj 2D Ma e ials and Applica ions (2023) 7:45 ; h ps://doi.o g/10.1038/s41699-023-00411-2
INTRODUCTION
The aqueous zinc-ion ba e y (ZIB) eme ges as a sus ainable
ene gy s o age de ice due o i s low-cos componen s and
en i onmen al iendliness
1–4
. I is also he mos in es iga ed
flexible ene gy s o age de ice due o i s sa e wea abili y. Howe e ,
many ZIB de ices a e cons uc ed using me al oxide-/polyme -
based in e cala ion- ype ca hodes (e.g., Mn, Ni, Ti, V, and
polyaniline)
5–8
, which limi s hei pe o mance due o hei low
heo e ical capaci y. Recen ly, sul u (S) ca hodes eme ged as an
inexpensi e al e na i e o he abo e ca hodes in ZIBs due o hei
low-cos , high heo e ical con e sion capaci y, and sa e Zn–S
con e sion po en ial in aqueous elec oly es
9–12
. Howe e , Zn–S
ba e ies a e s ill unde pe o ming in e ms o con e sion kine ics
and s abili y due o he insula ing na u e o sul u , sluggish Zn–S
con e sion eac ion, and he o ma ion o byp oduc s ha esul
in he loss o ac i e ma e ial
13,14
. To o e come he abo e issues, a
ew a emp s ha e been epo ed o imp o e he pe o mance o
sul u ca hodes by confining composi es wi h po ous ca bon
15,16
,
ca bon nano ubes
17
, ca bon nanofibe s
18
, Fe(CN)
64−
-doped poly-
aniline
19
, S@FeN
4
single si es/ni ogen-doped ca bon
20
, and sul u
in ionic liquid films
21
. Along wi h his, e o s ha e also been made
wi h modifica ions in elec oly es, i.e., adding ca aly ic iodine
edox addi i e
17
, mixing u ea as a co-media o
22
, sol a ion agen
s a egy by using eu ec ic elec oly e
23
, and using co-sol en s like
e aglyme
24
and e hylene glycol
18,25
. These e o s success ully
imp o ed he e e sibili y o Zn–S con e sion wi h a educed
ene gy ba ie .
To make he Zn–S ba e y a e sa ile componen , mo e e o is
needed o implemen e ficien ca hode confinemen wi h
ad anced s a egies and solid/gel- ype elec oly es ins ead o
liquid elec oly es ha could se e o de elop u u e flexible
ba e ies. Recen ly, he wo-dimensional (2D) ansi ion me al
ca bide (MXenes) ma e ials ha e eme ged as po en ial elec odes
and conduc i e confinemen ma e ials o imp o e ca hode
pe o mance in ZIBs due o hei high conduc i i y, la ge su ace
a ea, and di e se su ace unc ionali ies
26,27
. The model MXene,
Ti
3
C
2
T
x
, was ound as an e ficien bu e medium o inc ease Zn
2+
s o age in polyaniline ca hodes due o i s 2D nanoshee
mo phology, which p o ides a pla o m o as di usion pa h-
ways
28
. The confinemen o MXenes (e.g., Ti
3
C
2
T
x
and V
2
CT
x
) wi h
a ious me al oxide composi e ca hodes (e.g., MnO
229
,V
2
O
530,31
,
ZnMn
2
O
432
, and H
2
V
3
O
833
) g ea ly imp o ed he in e cala ion
pe o mance in ZIBs by enhanced conduc i i y and he impac o
su ace g oups. Li e al. epo ed aqueous I2=I edox kine ics
boos ed by MXene conduc i e confinemen o Zn-I
2
con e sion
chemis y benefi ed om he confinemen e ec and as e
cha ge ans e
34
. Looking a he e sa ili y o MXenes, i is
possible o design an MXene-confined sul u ca hode composi e
ha will enhance he Zn–S ba e y’s chemis y by p o iding
conduc i e confinemen o he sul u ca hode and inc easing he
ac i i y o edox addi i es like iodide– iiodide.
De eloping a flexible Zn–S ba e y wi h high pe o mance.
He ein, we p epa ed a flexible Zn–S ba e y using S@Ti
3
C
2
T
x
as
ca hode and AGE as gel elec oly e. The 2D mo phology and
me allic p ope y o Ti
3
C
2
T
x
o e conduc i e confinemen o he
sul u ca hode o imp o ed Zn–S edox kine ics and quick
di usion pa hs o he Zn
2+
ions. On he o he hand, he
amphiphilic na u e o AGE helps o de elop obus in e aces
wi h elec odes and es ic s he shu le o iodide species so hey
can benefi om egula ed sel -discha ge. The as- ab ica ed Zn–S
ba e y wi h S@Ti
3
C
2
T
x
ca hode o e s high powe capaci y, good
cycling s abili y, and excellen capaci y e en ion upon mul iple
bending modes. To demons a e a eal applica ion, he Zn–S
ba e ies we e connec ed in se ies o powe a digi al clock, ed-
1
Fu u e Ene gy and Inno a ion Labo a o y, Cen al Eu opean Ins i u e o Technology, B no Uni e si y o Technology, B no, Czech Republic.
2
Cen e o Ad anced Func ional
Nano obo s, Depa men o Ino ganic Chemis y, Facul y o Chemical Technology, Uni e si y o Chemis y and Technology P ague, P ague, Czech Republic.
3
Facul y o Elec ical
Enginee ing and Compu e Science, VSB - Technical Uni e si y o Os a a, Os a a, Czech Republic.
4
Depa men o Medical Resea ch, China Medical Uni e si y Hospi al, China
Medical Uni e si y, Taichung, Taiwan. ✉email: [email p o ec ed]om
www.na u e.com/npj2dma e ials
Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS
1234567890():,;
ligh -emi ing diode, and obo o p o ide a s eady powe supply
in a ious de o ma ions. To he bes o ou knowledge, his is an
exclusi e wo k o a Ti
3
C
2
T
x
-assis ed flexible Zn-S (aqueous) ba e y
has been epo ed.
RESULTS AND DISCUSSIONS
Syn hesis and mo phology s udy o S@Ti
3
C
2
T
x
To de elop an e ficien ca hode elec ode, S@Ti
3
C
2
T
x
was p epa ed
by liquid shea in si u sul u deco a ion o ex olia ed Ti
3
C
2
T
x
in he
p esence o su ac an by s ong mechanical blending (Fig. 1a).
Mo e de ails a e gi en in he expe imen al sec ion. This me hod
a oids ene gy-consuming high- empe a u e me hods, which a e
commonly used o blend S wi h hos ma e ials
15–17
. A e ha ,
ca bon clo h was used as a conduc i e subs a e o c ea e a flexible
S@Ti
3
C
2
T
x
ca hode elec ode (Fig. 1b, c). Finally, a flexible aqueous
Zn–S ba e y was de eloped by employing S@Ti
3
C
2
T
x
as a ca hode,
Zn oil as an anode, and AGE as an elec oly e, which shows
significan applica ions o powe a ious elec onic de ices (Fig. 1d,
e). The ba e y wo ks wi h a epo ed hyb id mechanism
17,24
du ing
he discha ge p ocess:Zn2þþSþI
3þ4e!ZnS þ3Iand du -
ing he cha ging p ocess, ZnS þ3I!I
3þSþZn2þþ4e.He e,
he p oposed highly conduc i e Ti
3
C
2
T
X
as ca hode composi e
p o ides confinemen syne gy o ac i a e he insula ed sul u and
iodine o as e and acile edox eac ions and alle ia e he
conduc i e channels o Zn ion di usion. On he o he side, he
e hylene oxide and p opylene oxide g oups o he AGE ma ix allow
he good dissolu ion o iodine and also es ic he di usion o
iodides
35,36
. Be o e examining he S@Ti
3
C
2
T
x
ca hode’s ole in
flexible Zn–S ba e ies and hei ac ual applica ion o powe
elec ical de ices, i is c ucial o fi s look a he s uc u al,
mo phological, and elec ochemical p ope ies o S@Ti
3
C
2
T
x
com-
posi e and AGE. He e, he S@Ti
3
C
2
T
x
composi e was cha ac e ized
sys ema ically by he mog a ime ic analysis (TGA), X- ay di ac ion
(XRD), scanning elec on mic oscopy (SEM), scanning ansmission
elec on mic oscopy (STEM), ene gy-dispe si e X- ay spec oscopy
(EDS), ansmission elec on mic oscopy (TEM), and high- esolu ion
scanning ansmission elec on mic oscopy (HR-STEM) o alida e
he successi e composi ion p epa a ion.
The SEM image o p is ine Ti
3
C
2
T
x
in Fig. 2a shows an o de ed
a angemen o 2D nanoshee s ack clus e s wi h a size o
~5–6 µm leng h and a isible gap be ween he shee s. The EDS
elemen a y mapping (Supplemen a y Fig. 1) o hese nanoshee
s acks confi ms he p esence o elemen s Ti, C, F, and O. Fu he ,
solu ion-shea ed Ti
3
C
2
T
x
was analyzed by STEM and ound o
con ain well-dispe sed Ti
3
C
2
T
x
nanoshee s (Fig. 2b) simila in size
o he s acks. TEM and HR-TEM images (Fig. 2c, d) o ew-laye
nanoshee s show good c ys allini y as confi med by selec ed a ea
elec on di ac ion (SAED, inse o Fig. 2d), indica ing nea spli s in
he Ti
3
C
2
T
x
s acks du ing solu ion shea ing. The STEM image and
co esponding EDS elemen a y mapping o shea ed S@Ti
3
C
2
T
X
a e
p esen ed in Fig. 2e. We can see clea ly ha S is e enly a ached o
he su ace o he Ti
3
C
2
T
x
nanoshee s, c ea ing a uni o m
S@Ti
3
C
2
T
x
laye s uc u e. The EDS mappings alida ed he
p esence o S, Ti, and C dis ibu ion.
TGA analysis conduc ed unde a ni ogen a mosphe e es i-
ma ed he sul u p opo ion o ~60 w % in he composi e
p epa ed using he solu ion shea ing me hod (Supplemen a y
Fig. 2). XRD was used o examine he c ys alline p ope ies o
S@Ti
3
C
2
T
x
composi es (Supplemen a y Fig. 3). The XRD pa e n o
Ti
3
C
2
T
X
indica es he b oad di ac ion peak a 2θ=~8° (002),
ep esen ing he e ficien spli s o nanoshee s h ough he
shea ing me hod
28
. In he composi e samples, Ti
3
C
2
T
x
peaks
eme ge in s ong peaks o S and he ep esen a i e peak o
Ti
3
C
2
T
x
, s ill isible below 2θ=8°, indica es a la ge dis ance
be ween he Ti
3
C
2
T
x
nanoshee s by e ec i e in si u S deco a ion.
S@Ti3C2Tx
ca hode
Zinc
Anode
Amphiphilic
Gel
Elec oly e
Sul u Ti3C2Tx Zn2+
=
Ti
= C= O, OH, F
Polyme
Iodides
abc
d
e
Fig. 1 Schema ic illus a ion o p epa ing flexible Zn-S ba e y ca hode based on S@Ti
3
C
2
T
x
o powe ing a down-scaled obo .
aSyn hesis o S@Ti
3
C
2
T
x
by solu ion shea -assis ed me hod. bMolecula schema ic o S@Ti
3
C
2
T
x
composi e. cDeposi ion on ca bon clo h.
dFlexible Zn–S ba e y wi h S@Ti
3
C
2
T
x
ca hode, Zn anode, and amphiphilic gel elec oly e-in used cellulose as a sepa a o . eDown-scaled
obo powe ed by he p oduced wea able Zn–S ba e y.
K.K. Soniga a e al.
2
npj 2D Ma e ials and Applica ions (2023) 45 Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS
1234567890():,;
XRD s udy sugges s an e ec i e physical blending o Ti
3
C
2
T
x
wi h
S wi hou oxida ion o chemical eac ions. The quali y and ex en
o he S@Ti
3
C
2
T
x
can be s udied om he su ace a ea o he
ma e ials. BET analysis o Ti
3
C
2
T
x
and S@Ti
3
C
2
T
x
was ca ied ou o
s udy he specific su ace a ea, which is an impo an pa ame e
o he quali y o elec odes. The adso p ion–deso p ion iso he m
o bo h ma e ials is p o ided in Supplemen a y Fig. 4. I is no iced
ha he su ace a ea o Ti
3
C
2
T
x
was 17.34 m
2
g
−1
, which dec eased
when blended wi h S (10.04 m
2
g
−1
), hus confi ming he compac
physical mo phology o he ca hode’s composi ion
37
. This can be
beneficial o be e di usion o Zn ions by imp o ed conduc i i y
in he p esence o Ti
3
C
2
T
x
and good adso p ion o iodides du ing
cha ge–discha ge.
Elec ochemical s o age s udy o S@Ti
3
C
2
T
x
When imp o ing he elec ochemical s o age capabili ies o
p epa ed S@Ti
3
C
2
T
x
ca hodes wi h an aqueous sys em, he
selec ion o he cu en collec o and elec oly e is e y impo an .
In he p esen case, we ha e adop ed hyd ophobic ca bon clo h as
a cu en collec o due o he non-pola p ope ies o elemen al
sul u . The elec oly e de eloped he e wi h zinc ace a e, iodine,
and he block copolyme is amphiphilic and possesses a sol–gel-
ype na u e o ensu e good in e acial con ac o ma ion
(Supplemen a y Fig. 5a); his is inspi ed by polyme hyd ogel
elec oly e om plu onic polyme , which p o ed excellen o
ZIBs
38
. To confi m he in e acial compa ibili y o he ca hode, we
compa ed he op ical obse a ion o a d op o liquid elec oly e on
op o ca bon clo h coa ed wi h p is ine Ti
3
C
2
T
x
and S@Ti
3
C
2
T
x
.
The elec ode su ace o S@Ti
3
C
2
T
x
composi ion becomes highly
hyd ophobic compa ed o he o me and seems incon enien o
he sys em (Supplemen a y Fig. 5b). The issue is sol ed by he
compac in e ace c ea ed due o he AGE elec oly e’s amphi-
philic and he mo- e e sible p ope ies, which allows i o be well-
we ed on he S@Ti
3
C
2
T
x
ca hode in he sol phase be o e u ning
in o a gel (Supplemen a y Fig. 5b). AGE is also esponsible o he
acile dissolu ion o iodine due o he p esence o polyme in he
ma ix; hence, i helps o m a acile I
−
/I
3
−
edox couple.
Supplemen a y Figu e 6 shows he na u e o iodine dissolu ion
in compa ison o elec oly es wi h and wi hou polyme and
e eals a clea solu ion wi h polyme by as e dissolu ion. The
AGE main ains good ionic conduc i i y o 4.01 S cm
−1
(Supple-
men a y Fig. 7 and supplemen a y equa ion 1) and shows a zinc-
ion ans e ence numbe o 0.45 measu ed om DC pola iza ion
be ween zinc-blocking elec odes (Supplemen a y Fig. 8 and
supplemen a y equa ion 2). The zinc s ipping–pla ing cycles o
AGE conduc ed be ween symme ical zinc elec odes esul in a
s abilized ol age p ofile o 100 cycles, indica ing he good
elec ochemical sui abili y o AGE (Supplemen a y Fig. 9). No ably,
AGE also shows a wide elec ochemical ope a ional ol age
window up o 2.0 V s. Zn sui able o sa e aqueous sys ems
(Supplemen a y Figu e 10). Fu he , he gel p ope y o AGE also
benefi s he flexibili y o he de ice
39
.
To e alua e he elec ochemical pe o mance o S@Ti
3
C
2
T
x
and
S@C (S confined wi h ca bon nanopowde ) ca hodes, h ee-
elec ode cyclic ol amme y (CV) was conduc ed in he I=I
3
solu ion (Supplemen a y Fig. 11). I is obse ed ha bo h S ca hodes
show e e sible edox peaks o I=I
3, simila ly e e enced o glassy
ca bon elec odes. Besides, educed cu en densi y was obse ed
on bo h ca hodes due o he p esence o insula ing S. Howe e ,
S@Ti
3
C
2
T
x
shows a highe elec ochemical esponse wi h low
pola iza ion compa ed o S@C, which indica es he supe io
conduc i i y and su ace o S@Ti
3
C
2
T
x
.Fu he ,Zn–S ba e ies we e
ab ica ed in CR2032 coin cells wi h he configu a ion o Zn/AGE-
cellulose sepa a o /S@Ti
3
C
2
T
x
-ca bon clo h. The ab ica ed de ice
builds up a s able open ci cui po en ial (OCP) o 1.068 ± 0.010 V s.
Zn/Zn
2+
, sligh ly de ia ing om he heo e ical OCP o he Zn–S
sys em explained elsewhe e (1.044 V s. Zn
2+
/Zn)
23
. This de ia ion
may be assigned o he composi e con ibu ion o a modified
ca hode and elec oly e sys em. Figu e 3a shows he CV scans o he
ca hodes S@Ti
3
C
2
T
x
and S@C be ween 0.05 and 1.6 V a 0.1 mV s
−1
scan speed, e ealing a ba e y- ype quasi- e e sible cha ac e is ic.
The ca hodic peak eco ded a 0.5 V s. Zn/Zn
2+
belongs o he ZnS
o ma ion and he anodic peak a 1.47 V s. Zn/Zn
2+
is o he
e o ma ion o sul u om ZnS in aqueous elec ochemis y
19,24
.The
edox peaks o S@Ti
3
C
2
T
x
a e sha p and include a la ge s o age a ea
compa ed o b oad and educed S@C peaks, indica ing he supe io
confinemen e ec and as e zinc con e sion s o age.
Figu e 3b illus a es he gal anos a ic cha ging–discha ging
(GCD) ol age p ofile o bo h elec odes wi h simila ol age ange
a a cu en densi y o 300 mA g
−1
. The S@Ti
3
C
2
T
x
deli e ed highe
Zn s o age and an imp o ed elec ochemical p ofile wi h a lowe
pola iza ion ol age window compa ed o he ca bon sca old. The
deli e ed specific capaci y o S@Ti
3
C
2
T
x
is 772.7 mAh g
−1
, which is
highe han he con en ional S@C ca hode (491.7 mAh g
−1
). He e,
Ti
3
C
2
T
x
could p o ide a be e -conduc ing en i onmen and Zn
ion anspo flux ha leads he enhanced s o age pe o mance.
The capaci y o he S@Ti
3
C
2
T
x
/AGE-based de ice is imp o ed
compa ed o a ailable epo s o gel-based Zn-S ba e y as lis ed
in Fig. 3h
18,19,21
and also eaches an imp essi e ene gy densi y o
363.16 Wh kg
−1
, which is abo e he epo ed solid-s a e ZIBs
38–43
.
Supplemen a y Figu e 12 enlis s he capaci y o a ious epo ed
MXene-suppo ed ca hodes o he ZIBs
28–34,40–43
as S@Ti
3
C
2
T
x
ca hodes b eak he specific capaci y limi a ion o such ca hodes.
5 µm
5 µm 200 nm
1 µm 1 µm 1 µm 1 µm
TiSC
abc
e
d
100 nm
Fig. 2 Mo phology s udy. a SEM image o p is ine Ti
3
C
2
T
X.
bSTEM image o shea ed Ti
3
C
2
T
X
nanoshee . cTEM image o Ti
3
C
2
T
X
nanoshee .
dHR-TEM image o Ti
3
C
2
T
X
nanoshee (inse ep esen s SAED pa e n). eSTEM o shea ed S@Ti
3
C
2
T
X
and co esponding EDS elemen a y
mapping.
K.K. Soniga a e al.
3
Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS npj 2D Ma e ials and Applica ions (2023) 45
This indica es ha he combina ion o S and MXene can be a
p omising high-capaci y ca hode compa ed o o he combina-
ions wi h MXenes.
To unde s and he edox kine ics in hese wo di e en
en i onmen s, he cha ge ans e and ion di usion in he
elec ode a e s udied using elec ochemical impedance spec o-
scopy (EIS). The ob ained Nyquis plo s om EIS a e shown in
Fig. 3c and he inse is he Randles equi alen ci cui used o
ex ac he esis ance pa ame e s
44
. The S@Ti
3
C
2
T
x
ca hode
elec ode shows low bulk esis ance (R
s
=11.12 Ω) and cha ge
ans e esis ance (R
c
=16.83 Ω), whe eas he S@C elec ode
shows R
s
=14.77 Ωand R
c
=45.47 Ω, indica ing a good conduc-
i e pla o m and as e cha ge ans e in MXene confinemen . The
kine ics o Zn
2+
ions in he elec ode ma ix can be es ima ed by
he Wa bu g ac o , which is ob ained om he ela ionship o Z
eal
and he low- equency egion o he EIS spec um eflec ed as a
s aigh line
44
. Figu e 3d illus a es he ela ionship be ween Z
eal
and he low- equency egion o he EIS spec um, and he slope o
his g aph is he Wa bu g ac o based on supplemen a y
equa ions (3) and (4) in he Supplemen a y In o ma ion, and i is
in e sely p opo ional o he di usion. The lowe alue o he
Wa bu g ac o o S@Ti
3
C
2
T
x
(σ=5.69) sugges s as e di usion
kine ics o Zn
2+
ions due o acile confinemen suppo o a 2D
mo phology belonging o la ge mic o-size Ti
3
C
2
T
x
(3.40 ± 1.2 µm).
The S@C ealizes a high Wa bu g ac o (σ=6.42), meaning a
slowe di usion ha may be ela ed o he small pa icle size o he
ca bon (0.72 ± 0.2 µm) su ounded wi h ine sul u
45
.
Fu he , he S@Ti
3
C
2
T
x
de ice was cycled a highe a es o 500,
700, and 1000 mA g
−1
and s ill deli e ed a capaci y o 344, 263, and
187 mAh g
−1
, espec i ely, while e aining coulombic e ficiency
abo e 90% (Fig. 3e). The pola iza ion ol age inc eased significan ly
a he high cu en a e ha may be ela ed o ising in esis ance
con ibu ion. The a e capabili y was analyzed o 50 cycles by
applying an inc emen al a e o 300 o 1000 mA g
−1
ollowed by a
e u n o 300 mAh g
−1
(Fig. 3 ). De ice capaci y declined o
137.2 mAh g
−1
a 1000 mA g
−1
and e u ned o he same pe o -
mance a he ini ial a e, indica ing acile and well-con olled ene gy
s o age. Fu he , he de ice shows s able pe o mance o 300 cycles
and e ained capaci y e en ion o 92.8% excep o a ew ini ial
cycles (Fig. 3g). The ade in capaci y obse ed he e is o en
associa ed wi h he loss o ac i e sul u in aqueous media due o he
o ma ion o sul a e byp oduc s a he ca hode su ace
(2ZnS þ4H2Oþ10e!2Zn2þþSO2
4þSþ8Hþ)
20,22,24
.The
XPS spec a o he p is ine and cycled ca hode confi m he p esence
o sul a e and zinc in he ca hode as e idenced by byp oduc s on
he cycled ca hode (Supplemen a y Fig. 13).
The highe ac i e ma e ial-loaded de ices we e ab ica ed o
explo e he possibili y o scaling o he Zn–S ba e y. I can also
deli e a capaci y o 522 mAh g
−1
and 400 mAh g
−1
o loading o
3.0 and 5.0 mg cm
−2
, espec i ely (Supplemen a y Fig. 14). I was
ound ha he capaci y is linea
ill 1.5 mg cm
−2
, bu shows significan decay in capaci y a
loading abo e 2 mg cm
−2
due o possible inc eased in e nal
esis ance and a longe di usion pa hway
46
(Supplemen a y Fig.
15). I should be no ed ha de ice pe o mance is also capaci i ely
con ibu ed by Ti
3
C
2
T
x
, conduc i e ca bon, and ca bon clo h. Fo
he compa ison, he de ice wi h Ti
3
C
2
T
x
as a ca hode elec ode
was ab ica ed and es ed simila ly on he abo e de ices. A a
300 mA g
−1
a e, he Ti
3
C
2
T
x
can deli e a capaci y o
65.2 mAh g
−1
(Supplemen a y Fig. 16). Fo he sake o compa ison,
he de ice was also p epa ed wi h a liquid elec oly e wi h
modifica ion in polyme con en . The Zn–S ba e y wi h 5 w %
polyme con en elec oly e exhibi s a discha ge capaci y o
1016 mA g
−1
a 300 mA g
−1
, wi h supe io ac i a ion compa ed o
Fig. 3 Elec ochemical s udy o S@Ti
3
C
2
T
x
ca hodes in Zn-S ba e y. a CV o S@Ti
3
C
2
T
x
and S@C elec ode a a scan a e o 0.1 mV s
−1
and
bGCD cu es a 300 mA g
−1
.c,dNyquis plo s o S@Ti
3
C
2
T
x
and S@C, and co esponding cha ac e is ic o Z
eal
o high- equency ela ionship.
e, GCD cu es o S@Ti
3
C
2
T
x
a di e en a es and a e capabili y. gS abili y measu emen o S@Ti
3
C
2
T
x
a 500 mA g
−1
o 300 cycles.
hCompa ison o he specific capaci y pe o mance o S@Ti
3
C
2
T
x
a 300 mA g
−1
wi h epo ed Zn–S ba e ies wi h gel elec oly es.
K.K. Soniga a e al.
4
npj 2D Ma e ials and Applica ions (2023) 45 Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS
AGE due o high conduc i i y (Supplemen a y
Fig. 17). Howe e , liquid elec oly e su e s om issues ela ed o
di ficul sealing and leakage p oblems, and may no be sui able o
a obus flexible de ice.
In es iga ion o zinc-ion s o age in S@Ti
3
C
2
T
x
To in es iga e he cha ge–discha ge mechanism o Zn s o age, an
ex si u spec oscopy s udy was adop ed o iden i y he chemical
s o age con e sion in he S@Ti
3
C
2
T
x
ca hode by XRD, Raman, and
FT-IR (Fou ie - ans o m in a ed) echniques. Figu e 4a shows he
ypical cha ge–discha ge ol age p ofile o a Zn-S ba e y wi h
selec ed ol age poin s o ace he S o ZnS ans o ma ion and
ice e sa by XRD. The co esponding eco ded X- ay di ac ion
pa e ns a e p o ided in Fig. 4b. The ep esen a i e XRD peak o S
can be iden ified a 2θ=23° on he ca bon clo h, whe e he b oad
cha ac e is ic a 2θ=20–30° a ises om he ca bon clo h
subs a e as compa ed in he s udy. Fi s , he discha ge analysis
is ooled a a discha ge ol age o 0.4, 0.2, and 0.05 V, whe e he S
peak is con inuously dec eased while he new peaks ha a ise a
28°, 48°, and 56° belong o ZnS o ma ion. This obse a ion is in
good ag eemen wi h p e iously epo ed Zn–S sys ems
19,23
. F om
0.4 V o 0.2 V, ZnS o ma ion s a s and a 0.05 V he peaks a e
mo e in ensely isible. While in cha ging mode om 1.3 V o 1.6 V,
he ZnS peaks nea ly disappea wi h he e o ma ion o he sul u
peak. He e, he sul u peak is no in ense as i was in beginning,
which could be ela ed o sul u loss du ing he side eac ion and
sul a e o ma ion obse ed in he XPS s udy. This ac also
co ela es wi h he ep esen a i e b oad peak o Ti
3
C
2
T
x
nanoshee composi ion in he ca hode, which is isible in he
discha ged s a e bu is also isible in a ully cha ged s a e a 1.6 V.
These changes a e also obse ed in Raman spec oscopy whe e
he ini ial abso p ion cha ac e is ic o he ca hode being
consumed in he discha ge s a e and e o med again in he
cha ge s a e belongs o he consump ion and e o ma ion o S
(Supplemen a y Fig. 18). The FT-IR spec a p o ided in Fig. 4c
show he p ofiles o subsequen ini ial discha ge, cha ge, and
second discha ge, which alida e he e e sible cha ge–discha ge
cha ac e is ics om he iden ified peaks o ZnS (1624, 1376, and
1103 cm
−1
)
19,47
. Those peaks a e o med du ing he fi s
discha ge, pa ially disappea du ing cha ging, and hen e o m
again du ing he second cha ge. STEM and EDS analyses we e
pe o med o his cycled elec ode o obse e he dis ibu ion o
discha ged p oduc s and composi ions. Figu e 4d p esen s a STEM
image o he discha ged p oduc o cycled ca hode and
co esponding EDS elemen al mapping o a simila a ea iden ifies
he dis ibu ion o Ti, Zn, and S elemen s. I can be no ed ha he
scanning o he Zn elemen is iden ical o he S elemen scanning.
This is e iden and suppo s he p e ious obse a ion o sul u
consump ion and ZnS o ma ion obse ed in spec oscopic
me hods.
Usually, Zn–S aqueous ene gy s o age is benefi ed om sulfide
shu le- ee elec ochemis y compa ed o he Zn–MnO
2
sys em
23
,
bu he use o addi i es like I=I
3in elec oly es may impac he
ba e y wi h iodide di usion and leads o sel -discha ge. Howe e ,
he p esen Zn–S ba e y ealizes 98.1% capaci y e en ion a e
es ing 27 h sel -discha ge es by con olling e y well he
di usion, which may be by he combined e ec o AGE and
Ti
3
C
2
T
x
(Supplemen a y Fig. 19). To unde s and he ole o AGE
and Ti
3
C
2
T
x
on he con olling sel -di usion o iodide, liquid-s a e
Zn–S ba e ies o S@Ti
3
C
2
T
x
and S@C a e p epa ed wi h liquid
elec oly e and s udied he sel -di usion in de ices a e he
cha ging o 1.6 V (Supplemen a y Fig. 20a, b). The obse ed
capaci y e en ion o bo h ca hodes is 86.01% and 90.23% o
S@C and S@Ti
3
C
2
T
x
, espec i ely, which is qui e a bi lowe han
AGE-based de ices. The lowe decay obse ed in he S@Ti
3
C
2
T
x
sugges s pola su aces can play an impo an ole in holding he
iodides simila ly obse ed in Zn–I
2
and Li–S ba e ies
34,48
.To
isualize he di usion phenomena, a liquid elec oly e-based
beake cell and an AGE-based la e al de ice we e ab ica ed on a
glass subs a e, and biased cons an a 1.6 V o moni o he iodide
o ma ion and di usion. Supplemen a y Fig. 21 shows he g adual
o ma ion o iodides ha la e on di used h ough he elec oly e
and a eled o he Zn oil. In he case o AGE-based de ice, iodide
colo change was only ealized a he in e ace o he elec ode
and AGE (Supplemen a y Fig. 22). The mic o-le el pho og aph can
isualize he colo o ma ion e y clea ly, which is in a e y sho
ange. Fu he , he compa ibili y o Zn me al was compa ed wi h
AGE and liquid-based elec oly es o he S@Ti
3
C
2
T
x
ca hode o
iden i y he ole o AGE in s abilizing he Zn anode. Zn anode
mo phology was analyzed by SEM a he ini ial and hen cycled in
Fig. 4 Ex si u cha ac e iza ion o cha ged and discha ged sul u ca hode. a,bGCD and ol age poin s o XRD measu ed du ing one cycle.
cFT-IR spec oscopy o wo cycles. dSTEM and co esponding EDS elemen al analysis o he discha ged S@Ti
3
C
2
T
x
ca hode.
K.K. Soniga a e al.
5
Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS npj 2D Ma e ials and Applica ions (2023) 45

bo h elec oly es (Supplemen a y Fig. 23). The Zn anode in AGE
shows a uni o m su ace a he ini ial s a e ha becomes laye ed
a e long- e m cycling due o Zn s ipping and pla ing e en s.
This indica es ha he elec oly e is much mo e sui able wi h a Zn
anode. In he case o liquid elec oly es, he SEM image o Zn was
obse ed wi h une enly g own solid clus e s on he su ace. This
obse a ion sugges s ha he AGE and Ti
3
C
2
T
x
e ec i ely
con ibu e o ad ancing he Zn-S ba e y.
Flexible Zn–S ba e y and applica ions
To e alua e he flexibili y o his de ice, he ab ica ion o a Zn–S
flexible ba e y was p epa ed by a aching Zn oil o he flexible
plas ic subs a e o p o ide a flexible backbone. Figu e 5a shows
he a e capabili y o flexible Zn–S ba e y a di e en cu en
densi ies anging om 500 mA g
−1
o 2000 mA g
−1
. The capaci y
dec eases wi h inc easing cu en densi y, eaching up o
325 mA g
−1
a a slow a e and 137 mA g
−1
a a as e a e. The
flexible ba e y shows he ideal cha ge–discha ge edox p ofile
obse ed in he model coin cell de ice (Fig. 3e). Du ing he long-
e m s abili y a 700 mA g
−1
, i akes nea ly 20 cycles o achie e
s able pe o mance and hen e ains 82.7% capaci y wi h a e age
coulombic e ficiency o 98.3% (Fig. 5b). The as e cu en a e
along wi h scaled elec odes makes an impac on deg ada ion in
capaci y belonging o possible enhanced side eac ions and
cha ge losses. The pe o mance and s abili y o he flexible Zn–S
ba e y a e qui e supe io and compa able o ha epo ed o
flexible solid-s a e ZIBs wi h me al oxide ca hodes and sul u
ca hodes (Supplemen a y Tables 1 and 2).
Flexibili y analysis was pe o med by cycling he ba e y de ice
a 90° and 180° bending condi ions wi h a 500 mA g
−1
a e whe e
capaci y pe o mance was e ained a 81% and 72%, espec i ely,
compa ed o he fla de ice (Fig. 5c). Figu e 5d illus a es he
demons a ion o he p ac icali y o a flexible de ice wi h fla , ben
in an upwa d and down di ec ions, and wis ed while powe ing a
digi al clock wi h i (Supplemen a y Mo ie 1). The de ice an
undis u bed du ing he ope a ion, which sugges s he compac -
ness o he elec odes/elec oly e in e aces. To alida e flexibili y
in e ms o ene gy s o age pe o mance, he de ice was e alua ed
by moni o ing he OCP and specific capaci y a 90° o 500
bending cycles (Fig. 5e, ). I e ains i s OCP e y well wi h s able
Fig. 5 Flexible Zn-S ba e y and eal-wo ld applica ions. a Cha ge–discha ge p ofile o flexible Zn–S ba e y a di e en a es. bS abili y
p ofile o he flexible Zn–S ba e y. cSpecific capaci y o he flexible Zn–S ba e y a fla , 90°, and 180° bending. dPowe ing o a digi al clock
upon di e en bending ope a ion o flexible Zn–S ba e y. e–hFlexibili y analysis o de ices a long- e m bending cycles in e ms o OCP and
capaci y e en ion. iDischa ge p ofile o se ies-connec ed flexible Zn–S ba e ies. jDigi al pho og aphs showing he ol age o se ies-
connec ed flexible Zn–S ba e y. Real-wo ld applica ions o flexible Zn-S ba e y. kPowe ing o LED gadge wi h flexible Zn–S ba e y module.
lDC mo o -ope a ed oy obo powe ed wi h Zn-S ba e y module.
K.K. Soniga a e al.
6
npj 2D Ma e ials and Applica ions (2023) 45 Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS
capaci y measu ed a e e y 100 in e als and finally eaches 91%
capaci y e en ion. Fu he , he de ice was subjec ed o ex eme
180° bending o mo e han 300 cycles and s ill achie ed 86%
capaci y e en ion (Fig. 5g, h). O e all, he de ice demons a ed
good flexibili y and elec ochemical pe o mance.
The de eloped flexible Zn–S ba e y has he po en ial o
wea able applica ions and o un elec onic gadge s due o i s
high capaci y and flexibili y. Owing o good ene gy densi y, he
discha ge ol age o his ba e y ealizes deli e ing powe a a
e y low ol age, which may limi he applicabili y. To enable i o
p ac ical applica ion, we in es iga ed a Zn–S ba e y module
p epa ed by se ies connec ion o cells o achie e highe ou pu
ol age. The p epa ed module possesses good flexibili y as
demons a ed (Supplemen a y Fig. 24). Se ies-connec ed de ices
discha ge cu es and co esponding OCP a e p o ided in Fig. 5i, j.
In compa ison o a single de ice wi h a wo king ol age o 1.065 V,
he wo and h ee de ices connec ed in se ies exhibi 2.1 V and
3.2 V, espec i ely, wi h simila discha ge imes. The discha ge
ol age p ofile also showed pe iodic enhancemen in he ol age,
mainly imp o ed ini ially, which could be help ul o igge high-
ol age gadge s. Howe e , he quick ol age decay a e ini ial
gain may a ibu e o he inc eased ex e nal esis ance o module
de ices. Fo he demons a ion, a wea able w is bel o wo
se ies-connec ed Zn–S ba e ies was p epa ed o success ully
illumina e a ed-colo ed LED indica o and powe i o o e 5 min
(Fig. 5k). Nowadays, au omo i e obo ics un on DC mo o s
powe ed by igid li hium-ion ba e ies ha limi po abili y and
p esen sa e y and cos issues. He e, o demons a ion and o
highligh he po en ial o a flexible Zn–S ba e y wi h low-cos
componen s, we powe ed a oy obo equipped wi h a 1.5 V DC
mo o . The flexible Zn–S ba e y module designed he e can powe
and un he oy obo o 30–60 s wi h wo de ices (Fig. 5l and
Supplemen a y Mo ie 2). This demons a ion applica ion p o es
ha sys ema ic la ge-scale module design and de elopmen could
e ficien ly sol e he powe ing o obo ics wi h his low-cos ,
flexible Zn–S ba e y.
In his wo k, Ti
3
C
2
T
x
was deco a ed wi h S o use as ca hode
along wi h AGE o imp o e he pe o mance o flexible Zn-S
ba e ies. Illus a ions o wo composi ions o S@Ti
3
C
2
T
x
and S@C
elucida e he impac o Ti
3
C
2
T
x
in Zn–S edox imp o emen whe e
i plays an impo an ole o inc ease he edox kine ics,
con olling soluble iodide shu ling by pola su ace and p o iding
a backbone o as e Zn
2+
di usion channels. I is concluded ha
he AGE coupled wi h S@Ti
3
C
2
T
x
ca hode enables con ol o sel -
discha ge and also p o ec s he Zn anode agains co osion. The
de ice o he S@Ti
3
C
2
T
x
ca hode pe o ms wi h a high ene gy
densi y o 363.16 Wh kg
−1
, which is imp essi e compa ed o me al
oxide-based in e cala ion ca hodes popula o ZIBs. The flexibili y
and bending s udy showed good pe o mance a e many
de o ma ions wi hou significan de e io a ion o capaci y. Fo
he fi s ime, s a egic eal-scale applica ions o he flexible and
wea able Zn–S ba e y modules a e demons a ed o un an LED
display and powe a mo o ized ab ica ed down-scale obo by
connec ing Zn–S ba e ies in se ies. This case s udy and wo k
ep esen a low-cos op ion o u u e wea able de ices and also a
g een sou ce o ene gy o au omo i e obo ics.
METHODS
P epa a ion o S@Ti
3
C
2
T
x
composi es
S@Ti
3
C
2
Tx composi e (60 w % S) was p epa ed by in si u solu ion-
shea ed me hod by modifica ion in he p e iously epo ed
me hod
49
. Fi s , su ac an solu ion was p epa ed in mixed sol en
me hanol (40 %) and chlo o o m (60 %) by adding su ac an
sodium chola e (2 mg/mL). Acco ding o he equi emen o S and
Ti
3
C
2
T
x
composi ion, he weigh o bo h componen s in w /w %
was added o he su ac an solu ion whe e he concen a ion o
Ti
3
C
2
T
x
was kep a 3 mg/mL. The esul an solu ion was shea ed
a 15,000 pm o 45 min (15 min, 3 imes a 10-min in e als) in an
ice ba h wi h a s ainless s eel blade s i e om IKA. The blended
solu ion was hen aken o sol en e apo a ion unde s i ing a
50 °C. The d ied mass was pou ed in o he me hanol and washed
h ee imes o emo e sodium chola e om he composi e
ollowed by d ying o 12 h a 60 °C. The d ied mass con ains he
p opo ional composi ion weigh added o he solu ion. A simila
p ocedu e was used o p epa e he S@C ( ~ 60 w % S) sample by
eplacing ca bon powde wi h Ti
3
C
2
T
x
.
P epa a ion o amphiphilic gel elec oly e (AGE)
Amphiphilic gel elec oly e was p epa ed by ollowing ou
p e ious me hod
33
. 1 M aqueous zinc ace a e solu ion was
p epa ed wi h 0.20 w % iodine addi i e and mixed wi h 30 w %
(w/w) P123 plu onic block-copolyme
37,38
. B iefly, he polyme was
allowed o dissol e in solu ion o 3 h ollowed by gen le mixing
wi h a spa ula. Fu he , he gel was subjec ed o h ee
cooling–hea ing cycles (0 °C/25 °C) o sol-gel ansi ions o
achie e a uni o m gel phase elec oly e. Fo he ba e y
applica ion, a cellulose sepa a o was in used in he sol s a e o
achie e a uni o mly coa ed sepa a o a oom empe a u e in he
gel s a e.
Fab ica ion o elec odes and ba e y
The ca hode was p epa ed on ca bon clo h using a slu y coa ing
me hod. A fi s , as-p epa ed ac i e ma e ial (80 w %) and ca bon
black (10 w %) we e mixed well in a mo a o 30 min, and hen
he slu y was p epa ed in NMP wi h PVDF (10 w %) o a u he
30 min o mixing. The homogenized slu y was doc o -bladed on
he ca bon clo h and d ied a 70 °C o 24 h. The d ied elec ode
was hen uni o mly p essed well and cu in o a 1 cm
2
-sized piece.
The ac i e S loading o elec odes a ied om 0.8 o 1.0 mg cm
−2
o low loading, 3.0 o 5.0 mg cm
−2
o high loading, and 1.0 o
1.5 mg cm
−2
o he flexible ba e y and modules. The Zn oil was
used as an anode and polished o emo e he oxide laye . The
ba e y cell was ab ica ed in 2032 coin cells whe ein he fi s -
placed Zn oil was ollowed by a d op o sol-phase elec oly e and
elec oly e-in used sepa a o . Finally, he ca hode was placed on
op o he sepa a o and he de ice was sealed. Fu he , wo
cooling–hea ing cycles (0 °C/25 °C) we e applied o achie e
enough pene a ion o elec oly e and uni o m in e aces. In he
flexible de ice ab ica ion elec odes we e scaled o 3 cm
2
.An
anode was s uck on he flexible PET subs a e ollowed by he
placemen o he gel-in used sepa a o s and ca hode. The
sandwich assembly was sealed wi h glue ape wi h h ee laye s
o make i leak-p oo . The de ice was allowed o s abilize o 12 h
be o e obse ing measu emen s.
DATA AVAILABILITY
The da a ha suppo he findings o his s udy a e a ailable om he co esponding
au ho upon easonable eques .
Recei ed: 25 Janua y 2023; Accep ed: 15 June 2023;
REFERENCES
1. Lee, S., Hwang, J., Song, W.-J. & Pa k, S. Towa d high ene gy densi y aqueous zinc-
ion ba e ies: ecen p og ess and u u e pe spec i es. Ba e ies Supe caps 5,
e202200237 (2022).
2. Zhang, T. e al. Fundamen als and pe spec i es in de eloping zinc-ion ba e y
elec oly es: a comp ehensi e e iew. Ene gy En i on. Sci. 13, 4625–4665 (2020).
K.K. Soniga a e al.
7
Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS npj 2D Ma e ials and Applica ions (2023) 45
3. Jia, X., Liu, C., Neale, Z. G., Yang, J. & Cao, G. Ac i e ma e ials o aqueous zinc ion
ba e ies: syn hesis, c ys al, s uc u e, mo phology, and elec ochemis y. Chem.
Re . 120, 7795–7866 (2020).
4. Dong, H. e al. Insigh s on flexible zinc-ion ba e ies om lab esea ch o com-
me cializa ion. Ad . Ma e . 33, 2007548 (2021).
5. Li, N. e al. Highly flexible MnO
2
@polyaniline co e-shell nanowi e film owa d
subs an ially expedi ed zinc ene gy s o age. Chem. Eng. J. 452, 139408 (2023).
6. Han, Q. e al. Du able, flexible sel -s anding hyd ogel elec oly es enabling high-sa e y
echa geable solid-s a e zinc me al ba e ies. J. Ma e . Chem. A 6, 23046–23054 (2018).
7. Ma, Y. e al. Nanos uc u ed polyaniline–cellulose pape s o solid-s a e flexible
aqueous Zn-ion ba e y. ACS Sus ain. Chem. Eng. 6, 8697–8703 (2018).
8. Zhao, J. e al. High-pe o mance flexible quasi-solid-s a e Zinc-ion ba e ies wi h
laye -expanded anadium oxide ca hode and Zinc/s ainless s eel mesh compo-
si e anode. Nano Ene gy 62,94–102 (2019).
9. Sungjemmenla, Soni, C. B., Vinee h, S. K. & Kuma , V. Explo a ion o he unique
s uc u al chemis y o sul u ca hode o high-ene gy echa geable beyond-Li
ba e ies. Ad . Ene gy Sus ain. Res. 3, 2100157 (2022).
10. Liu, J. e al. Sul u -based aqueous ba e ies: elec ochemis y and s a egies. J. Am.
Chem. Soc. 143, 15475–15489 (2021).
11. Luo, L. W. e al. A Zn–S aqueous p ima y ba e y wi h high ene gy and fla
discha ge pla eau. Chem. Commun. 57, 9918–9921 (2021).
12. Liu, D. e al. A du able ZnS ca hode o aqueous Zn-S ba e ies. Nano Ene gy 101,
107474 (2022).
13. Xu, Z. e al. The key ole o concen a ed Zn(OTF)
2
elec oly e in he pe o mance
o aqueous Zn–S ba e ies. Chem. Commun. 58, 8145–8148 (2022).
14. Liu, J., Ye, C., Wu, H., Ja oniec, M. & Qiao, S. Z. 2D mesopo ous zincophilic sie e o
high- a e sul u -based aqueous zinc ba e ies. J. Am. Chem. Soc. 145, 5384–5392
(2023).
15. Dai, C. e al. Maximizing ene gy s o age o flexible aqueous ba e ies h ough
decoupling cha ge ca ie s. Ad . Ene gy Ma e . 11, 2003982 (2021).
16. Dai, C. e al. A cascade ba e y: coupling wo sequen ial elec ochemical eac ions
in a single ba e y. Ad . Ma e . 33, 2105480 (2021).
17. Li, W., Wang, K. & Jiang, K. A low cos aqueous Zn-S ba e y ealizing ul ahigh
ene gy densi y. Ad . Sci. 7, 2000761 (2020).
18. Ami i, A., Selle s, R., Na aghi, M. & Polyca pou, A. A. Mul i unc ional quasi-solid-
s a e zinc−sul u ba e y. ACS Nano 17, 1217–1228 (2023).
19. Zhang, H. e al. Redox ca alysis p omo ed ac i a ion o sul u edox chemis y o
ene gy-dense flexible solid-s a e Zn–S ba e y. ACS Nano 16, 7344–7351 (2022).
20. Zhang, W. e al. Bidi ec ional a omic i on ca alysis o sul u edox con e sion in
high-ene gy flexible Zn-S ba e y. Ad . Fun. Ma e . 33, 2210899 (2023).
21. Zhao, Y. e al. Ini ia ing a e e sible aqueous Zn/sul u ba e y h ough a “liquid
film. Ad . Ma e . 32, 2003070 (2020).
22. Chang, G. e al. Bi unc ional elec oly e addi i e wi h edox media ion and
capaci y con ibu ion o sul u ca hode in aqueous Zn-S ba e ies. Chem. Eng. J.
457, 141083 (2023).
23. Cui, M., Fei, J., Mo, F., Lei, H. & Huang, Y. Ul a-high-capaci y and dend i e- ee zinc
−sul u con e sion ba e ies based on a low-cos deep eu ec ic sol en . ACS Appl.
Ma e . In e aces 13, 54981–54989 (2021).
24. Yang, M. e al. Boos ing ca hode ac i i y and anode s abili y o Zn-S ba e ies in
aqueous media h ough cosol en -ca alys syne gy. Angew. Chem. In . Ed. 61,
e202212666 (2022).
25. Zhou, T. e al. Regula ing uni o m nuclea ion o ZnS enables low-pola ized and
high s able aqueous Zn-S ba e ies. Ma e . Today Ene gy 27, 101025 (2022).
26. Ja ed, M. S. e al. The eme gence o 2D MXenes based Zn-ion ba e ies: ecen
de elopmen and p ospec s. Small 18, 2201989 (2022).
27. Li, X. e al. Mxene chemis y, elec ochemis y and ene gy s o age applica ions.
Na . Re . Chem. 6, 389–404 (2022).
28. Liu, Y. e al. Sul onic-g oup-g a ed Ti
3
C
2
Tx MXene: a sil e bulle o se le he
ins abili y o polyaniline owa d high-pe o mance Zn-ion ba e ies. ACS Nano 15,
9065–9075 (2021).
29. Qi, M. e al. Th ee-dimensional in e connec ed ul a hin manganese dioxide
nanoshee s g own on ca bon clo h combined wi h Ti
3
C
2
T
x
MXene o high-
capaci y Zinc-ion ba e ies. J. Colloid In e ace Sci. 615, 151–162 (2022).
30. Venka ka hick, R. e al. Vanadium-based oxide on wo-dimensional anadium
ca bide MXene (V
2
O
x
@V
2
CT
x
) as ca hode o echa geable aqueous zinc-ion,
ba e ies. ACS Appl. Ene gy Ma e . 3, 4677–4689 (2020).
31. Zhao, F. e al. In si u cons uc ing amo phous V
2
O
5
@Ti
3
C
2
T
x
he e os uc u e o high-
pe o mance aqueous zinc-ion ba e ies. J. Powe Sou ces 544, 231883 (2022).
32. Shi, M. e al. 3D assembly o MXene-s abilized spinel ZnMn
2
O
4
o highly du able
aqueous zinc-ion ba e ies. Chem. Eng. J. 399, 125627 (2020).
33. Liang, P. e al. He e ogeneous in e ace-boos ed zinc s o age o H
2
V
3
O
8
nano-
wi e/Ti
3
C
2
T
x
MXene composi e owa d high- a e and long cycle li espan aqueous
zinc-ion ba e ies. Ene gy S o . Ma e . 50,63–74 (2022).
34. Li, X. e al. Enhanced edox kine ics and du a ion o aqueous I
2
/I−con e sion
chemis y by Mxene confinemen . Ad . Ma e . 33, 2006897 (2021).
35. Soniga a, K. K., Zhao, J., Machhi, H. K., Cui, G. & Soni, S. S. Sel -assembled solid-
s a e gel ca holy e comba ing iodide di usion and sel -discha ge o a s able
flexible aqueous Zn–I
2
ba e y. Ad . Ene gy Ma e . 10, 2001997 (2020).
36. Machhi, H. K., Soniga a, K. K., Ba iya, S. N., Soni, H. P. & Soni, S. S. Hie a chically
po ous me al−o ganic gel hos ing ca holy e o limi ing iodine di usion and sel -
discha ge con ol in sus ainable aqueous zinc−I
2
ba e ies. ACS Appl. Ma e .
In e aces 13, 21426–21435 (2021).
37. Bao, W. e al. Facile syn hesis o c umpled ni ogen-doped Mxene nanoshee s as
a new sul u hos o li hium–sul u ba e ies. Ad . Ene gy Ma e . 8, 1702485
(2018).
38. Zhao, J. e al. A sma flexible zinc ba e y wi h cooling eco e y abili y. Angew.
Chem. In . Ed. 56, 7871–7875 (2017).
39. Soniga a, K. K. e al. A sma flexible solid s a e pho o ol aic de ice wi h in e -
acial cooling eco e y ea u e h ough he mo e e sible polyme gel elec oly e.
Small 14, 1800842 (2018).
40. Li, M. e al. Halogena ed Ti
3
C
2
MXenes wi h elec ochemically ac i e e minals o
high-pe o mance zinc ion ba e ies. ACS Nano 15, 1077–1085 (2021).
41. Li, X. e al. Ve ically aligned Sn
4+
p ein e cala ed Ti
2
CT
X
MXene sphe e wi h
enhanced Zn ion anspo a ion and supe io cycle li espan. Ad . Ene gy Ma e .
10, 2001394 (2020).
42. Zhu, X. e al. Supe io -pe o mance aqueous zinc-ion ba e ies based on he in si u
g ow h o MnO
2
nanoshee s on V
2
CT
X
MXene. ACS Nano 15,2971–2983 (2021).
43. Shi, J. e al. The high-pe o mance MoO
3−x
/MXene ca hodes o zinc-ion ba e ies
based on oxygen acancies and elec oly e enginee ing. Nano Ene gy 91, 106651
(2022).
44. Ba d, A. J. & Faulkne , L. R. Elec ochemical Me hods. 2 Edn., 211 (JOHN WILEY &
SONS, INC. 2001).
45. Bläubaum, L. e al. Impac o pa icle size dis ibu ion on pe o mance o li hium-
ion ba e ies. Chem. Elec o Chem. 7, 4755–4766 (2020).
46. Kim, Y. e al. In es iga ion o mass loading o ca hode ma e ials o high ene gy
li hium-ion ba e ies. Elec ochem. Commun. 147, 107437 (2023).
47. Wang, M., Zhang, Q., Hao, W. & Sun, Z.-X. Su ace s oichiome y o zinc sulfide and i s
e ec on he adso p ion beha io s o xan ha e. Chem. Cen . J. 5, 732011 (2011).
48. Pai, R. e al. Tuning unc ional wo-dimensional Mxene nanoshee s o enable
e ficien sul u u iliza ion in li hium-sul u ba e ies. Cell Rep. Phys. Sci. 2, 100480
(2021).
49. Mayo ga-Ma inez, C. C., Gusmão, R., So e , Z. & Pume a, M. Pnic ogen-based
enzyma ic phenol biosenso s: phospho ene, a senene, an imonene, and bis-
mu hene. Angew. Chem. In . Ed. 58, 134–138 (2019).
ACKNOWLEDGEMENTS
K.K.S. acknowledges he financial suppo by he Eu opean Union’s Ho izon 2020
esea ch and inno a ion p og am unde he Ma ie Skłodowska-Cu ie G an
ag eemen no. 101067295. We acknowledge he CzechNanoLab Resea ch In a-
s uc u e suppo ed by MEYS CR (LM2018110). M.P. acknowledges he financial
suppo o he Ad anced Func ional Nano obo s p ojec (Reg. No. CZ.02.1.01/0.0/0.0/
15_003/0000444 financed by he EFRR). We acknowledge P o . Ma in T unec, CEITEC
BUT o he mog a ime ic analysis.
AUTHOR CONTRIBUTIONS
K.K.S.: ma e ial p epa a ion, de ice ab ica ion, elec ochemis y, da a analysis o BET,
XRD, TEM, and Raman (measu ed a UCT cen al acili y), XPS measu emen and
analysis (CEITEC Nano), and w i ing he o iginal d a ; J.V.V.: SEM and EDS
measu emen s, gadge esou ces, and w i ing o iginal d a ; C.C.M.-M.: concep ualiza-
ion, supe ision, and e ised o iginal d a ; M.P.: financial suppo , me hodology,
supe ision, ini ia ed and o e saw he p ojec . All au ho s con ibu ed o w i ing he
manusc ip .
COMPETING INTERESTS
The au ho s decla e no compe ing in e es s.
ADDITIONAL INFORMATION
Supplemen a y in o ma ion The online e sion con ains supplemen a y ma e ial
a ailable a h ps://doi.o g/10.1038/s41699-023-00411-2.
Co espondence and eques s o ma e ials should be add essed o Ma in Pume a.
Rep in s and pe mission in o ma ion is a ailable a h p://www.na u e.com/
ep in s
K.K. Soniga a e al.
8
npj 2D Ma e ials and Applica ions (2023) 45 Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS
Publishe ’s no e Sp inge Na u e emains neu al wi h ega d o ju isdic ional claims
in published maps and ins i u ional a filia ions.
Open Access This a icle is licensed unde a C ea i e Commons
A ibu ion 4.0 In e na ional License, which pe mi s use, sha ing,
adap a ion, dis ibu ion and ep oduc ion in any medium o o ma , as long as you gi e
app op ia e c edi o he o iginal au ho (s) and he sou ce, p o ide a link o he C ea i e
Commons license, and indica e i changes we e made. The images o o he hi d pa y
ma e ial in his a icle a e included in he a icle’s C ea i e Commons license, unless
indica ed o he wise in a c edi line o he ma e ial. I ma e ial is no included in he
a icle’s C ea i e Commons license and you in ended use is no pe mi ed by s a u o y
egula ion o exceeds he pe mi ed use, you will need o ob ain pe mission di ec ly
om he copy igh holde . To iew a copy o his license, isi h p://
c ea i ecommons.o g/licenses/by/4.0/.
© The Au ho (s) 2023
K.K. Soniga a e al.
9
Published in pa ne ship wi h FCT NOVA wi h he suppo o E-MRS npj 2D Ma e ials and Applica ions (2023) 45