The Influence of Solvents and Salts on the Properties of High-Voltage Cathode Materials

In . J. Elec ochem. Sci., 10 (2015) 6288 - 6301 In e na ional Jou nal o ELECTROCHEMICAL SCIENCE www.elec ochemsci.o g The In luence o Sol en s and Sal s on he P ope ies o High- Vol age Ca hode Ma e ials T. Kazda1,*, J. Vond ák1, M. Sedlaříko á1, P.Gómez-Rome o 2, M. Musil1,P Čudek1, A. Fedo ko á S ako á1 and V. Kašpá ek3 1 Depa men o Elec ical and Elec onic Technology, Facul y o Elec ical Enginee ing and Communica ion, BUT, Technická 10, 616 00 B no, Czech Republic 2 Ins i u Ca alà de Nanociència y Nano ecnologia, ICN2 (CSIC-ICN), Consejo Supe io de In es igaciones Cien í icas, Campus UAB 08193, Bella e a (Ba celona), Spain 3 CEITEC BUT, B no Uni e si y o Technology, Technicka 10, 616 00 B no, Czech Republic *E-mail: [email p o ec ed]c. u b .cz Recei ed: 22 Ma ch 2015 / Accep ed: 29 May 2015 / Published: 24 June 2015 Li hium - ion ba e ies play an inc easingly impo an ole in he ba e y indus y and hey ha e become he dominan sou ce o ene gy in he ecen yea s, especially o po able elec onic de ices due o hei high g a ime ic ene gy densi y. This a icle examines he in luence o mix u es o sol en s wi h di e en combina ions o li hium sal s on he s abili y o wo ypes o high- ol age ca hode ma e ials: LiNi0.5Mn1.5O4 and LiC 0.1Ni0.4Mn1.5O4 p oduced by a solid phase eac ion. These ma e ials we e combined wi h se e al di e en elec oly es, cycled a a ious loads and highe empe a u e. Va ious combina ions o sol en s e hylene ca bona e (EC), dime hyl ca bona e (DMC) and Te ahyd o hiophene 1.1-dioxide (Sul olane) we e used o hese measu emen s. Sal s LiPF6 , LiNO3 and LiTFSI we e used. The in luence o sol en s and sal s on he p ope ies o high- ol age ca hode ma e ials was es ed by cycling a di e en cu en loads and by cycling a high empe a u e. I was ound ou , by LSV analysis, ha he addi ion o Sul olane inc eases he s abili y o elec oly e. The addi ion o ch omium o he ca hode ma e ial LiNi0.5Mn1.5O4 causes inc easing o capaci y and s abili y a high empe a u e. The combina ion o he ca hode ma e ial LiC 0.1Ni0.4Mn1.5O4 wi h he elec oly e 1.5 M LiPF6 EC:DMC:Sul olane 1:2:1 w/w/w leads o inc eased s abili y in compa ison wi h o he elec oly es. Keywo ds: Li hium ion ba e y, LiNi0.5Mn1.5O4, elec oly e, sul olane 1. INTRODUCTION Highe ol age ma e ials a e mos ly based on ma e ial LiMn2O4. I is i s spinel s uc u e ha makes i mo e s able han LiCoO2. This ma e ial is less oxic because o he use o Mn, i has low In . J. Elec ochem. Sci., Vol. 10, 2015 6289 exo he mic co up ion. I s speci ic capaci y is ~ 120 mAh/g and he ol age agains li hium is 4 V.[1-3] I one ou h o manganese is subs i u ed by nickel, his ma e ial can be cha ged up o 5 V and he ol age agains li hium abou 4.7 V. This ol age is he e o e abou 1 V mo e han by o he commonly used ma e ials oday.[1-2] The heo e ical capaci y o LiNi0.5Mn1.5O4 ma e ial is ~ 147 mAh/g. I s ene gy densi y is 700Wh/kg due o i s capaci y and high ol age which is app oxima ely 20% highe han LiCoO2 and 30% highe han LiFePO4.[4] The ma e ial emains s able du ing cycling and handles well by highe cu en loads hanks o he spinel s uc u e. This ca hode ma e ial eaches he high ol age using se e al oxida ion s eps a which he e occu s con e sion LiNi0.5IIMn1.5IIIO4/Ni0.5IVMn1.5IVO4. Mn3+ oxidizes o Mn4+ a 4 V s Li and subsequen ly Ni2+ is oxidized o Ni3+ a he ol age ange 4.7 – 4.8 V s Li and hen o Ni4+.[5,6] The esul o hese successi e changes o alence o nickel is joining wo discha ge pla eaus in one e y s able discha ge pla eau. Two ypes o ca hode ma e ials (LiNi0.5Mn1.5O4 and i s modi ica ion LiC 0.1Ni0.4Mn1.5O4) we e chosen o he expe imen in his a icle hanks o hese p ope ies. The Modi ica ion o he ma e ial LiNi0.5Mn1.5O4 using ch omium is used o inc ease he s abili y o he ca hode ma e ial du ing cycling and highe loads. [1,7-11] C is mos o en a pa ial eplacemen o Ni du ing he p ocess o doping LiNi0.5Mn1.5O4 by ch omium. The ionic adius o C +3 is 0.615 Å which is close o he ionic adius o Ni+2 (0.65 Å). This pa ial subs i u ion – o example in LiC 0.05Ni0.45Mn1.5O4 - leads o he imp o ed elec ochemical p ope ies due o highe s eng h o he bond C -O han he bond be ween Ni- and Mn-O. This s onge C -O bond leads o an inc ease in he s eng h o he s uc u e and main ains i s p ope ies du ing long e m cycling e en a highe loads. [1,7,8] The modi ica ion LiC 0.05Ni0.45Mn1.5O4 o al e na i ely LiC 0.2Ni0.4Mn1.4O4 a e mos equen ly men ioned in scien i ic a icles. [8-11] The modi ica ion LiC 0.1Ni0.4Mn1.5O4 was chosen o his a icle o e i y whe he doping by C in a speci ic a io can imp o e he ma e ial p ope ies. The main pa o his a icle ocuses on in es iga ion o he e ec o u ilized elec oly es on he elec ochemical p ope ies o hese wo ca hode ma e ials. EC (e hylene ca bona e), DMC (dime hyl ca bona e) and sul olane we e chosen as sol en s. EC and DMC a e commonly used as sol en s and sul olane was chosen because o i s highe he mal s abili y and i was also expec ed i would be mo e s able a highe ol ages.[12] LiPF6, LiNO3 and LiTFSI we e chosen as sal s. The LiNO3 sal was selec ed o he assump ion ha i s addi ion in o he mix will inc ease he s abili y o he elec oly e. LiTFSI is used as a s able sal o Li- S ba e ies and i was chosen o he alida ion o he s abili y o hese ca hode ypes. [13] 2. EXPERIMENTAL The me hod o eac ion in solid s a e was chosen o he p oduc ion o his ma e ial. P ecu so s based on ca bona es and oxides we e chosen as basic ma e ials o he p oduc ion. Li2CO3 (Li hium(II) ca bona e), MnCO3 (Manganese ca bona e), NiO (Nickel oxide) and C 2O3 (Ch omium(III) oxide) we e chosen in ou case; hese ma e ials we e mixed in a s oichiome ic a io o 0.02 mol/l. The wo- s ep annealing p ocess was selec ed o he p epa a ion. Selec ed p ecu so s a e milled oge he o 4h du ing he i s s ep o his p ocess. In he i s annealing s ep, he esul an mix u e is annealed a 600 °C o 10h. The second s ep is annealing a 900 °C o 15h. [14] A e his syn hesis we ob ain In . J. Elec ochem. Sci., Vol. 10, 2015 6290 ma e ials wi h ace-cen e ed spinel s uc u e he e o e known as diso de ed. The p epa ed ma e ial was hen mixed in o a mix u e consis ing o NMP (N-Me hyl-2-py olidon) (sol en ), PVDF (Poly inyliden luo id) (binde ) and ca bon Supe P. The weigh a io o he ma e ials was: ac i e ma e ial 80%, Supe P 10%, PVDF 10%. The esul ing mix u e was subsequen ly deposi ed on an Al oil, d ied and p essed by he p essu e o 3200 kg/cm2. A disk wi h a diame e o 18 mm was cu ou o he coa ed aluminium oil and inse ed in o he elec ochemical es cell El-Cell© ECC-STD. The assembly was done in a glo e box illed wi h a gon a mosphe e. Me al Li hium was used as a ma e ial o he anode and he elec oly e was soaked in a glass ib e sepa a o . 1 M LiPF6 EC:DMC 1:1 w/w, 1.5 M LiPF6 EC:DMC 1:2 w/w, 1.5 M LiPF6 + 0.1 M LiNO3 EC:DMC 1:2 w/w, 1.5 M LiPF6 EC:DMC:Sul olane 1:2:1 w/w/w, 1.5 M LiPF6 + 0.1 M LiNO3 EC:DMC:Sul olane 1:2:1 w/w/w, 0.75 M LiTFSI + 0.1 M LiNO3 EC:DMC 1:2 w/w and 0.75 M LiTFSI + 0.1 M LiNO3 EC:DMC:Sul olane 1:2:1 w/w/w we e used as elec oly es. Linea Sweep Vol amme y (LSV) was used o es ing o he s abili y o elec oly es in he ol age window om 3.0 o 5.2 V e sus li hium. Scan a e was se o 5 mV/s and 1 mV/s. Gal anos a ic cycling was used o measu ing elec odes wi h di e en elec oly es; he po en ial window was se om 3.0 o 5.1 V e sus li hium. Two cycles o cha ging and discha ging ha e always been ca ied ou du ing which he used cha ging and discha ging cu en s we e 0.5 C (calcula ed om he weigh o he deposi ed ma e ial p o ided ha he capaci y o he ma e ial is 120 mAh/g). The eal alue o capaci y o he sample was deduc ed om hese wo cycles and he sample was hen exposu ed o long e m cycling du ing which i was cycled en imes by 0.5 C cu en . I was subsequen ly cycled i e imes by 1 C cu en , hen i e imes by 2 C cu en and hen i e imes by 5 C cu en . Nex s ep was cycling again i e imes by 2 C cu en , again i e imes by 1 C cu en , again i e imes by 0.5 C cu en , and inally he e we e en cycles by 0.5 C cu en a he empe a u e o 50 °C. SEM mic oscope TESCAN VEGA3 XMU whi B uke EDAX analyze was used o de e mine he dis ibu ion o he elemen s in he ma e ials. TGA analysis was used o he compa ison o s uc u al s abili y o he syn hesized ca hode ma e ial. 3. RESULTS AND DISCUSSION I is e iden ha he decomposi ion o elec oly es wi h sal s LiTFSI and LiNO3 occu s a e exceeding o 3.7 V when compa ing wi h he cu es in Fig. 1. The elec oly e 1.5 M LiPF6 EC:DMC 1:2 showed lowe s abili y om he o he elec oly es. The s abili y o he elec oly e was inc eased a e he addi ion o sal LiNO3 and i was e en be e a e he addi ion o Sul olane. The elec oly e 1.5 M LiPF6 EC:DMC:Sul olane 1:2:1 appea ed o be he mos s able. The LSV a a scan a e o 1 mV/s is shown in Fig. 2. I is e iden om hese g aphs ha he lowes s abili y again exhibi he elec oly es wi h he sal mix u e o LiTFI and LiNO3. Be e s abili y was again disco e ed, like in he p e ious measu emen , a e he addi ion o LiNO3 sal in o he elec oly e 1.5 M LiPF6 EC:DMC 1:2. 1.5 M LiPF6 EC:DMC:Sul olane 1:2:1 seems o be he mos s able elec oly e again. The elec oly es wi h a mix u e o LiTFI and LiNO3 sal s we e disca ded o he nex measu emen s o he p ope ies o ca hode ma e ials wi h di e en elec oly es due o hei high ins abili y. A simila ins abili y in he In . J. Elec ochem. Sci., Vol. 10, 2015 6291 egion abo e 4 V was shown also by he commonly used elec oly e 1 M LiPF6 EC: DMC 1:1 which is e iden a bo h scan a es. Fo his eason, he con en ional elec oly e 1 M LiPF6 EC: DMC 1:1 was excluded om he nex measu emen . -0.05 0.00 0.05 0.10 0.15 0.20 0.25 2.5 3.0 3.5 4.0 4.5 5.0 5.5 I [mA/cm2] UWE [V] 1.5M LiPF₆ EC:DMC 1:2 1.5M LiPF₆ EC:DMC:Sul olane 1:2:1 1.5M LiPF₆+ 0.1 M LiNO₃ EC:DMC 1.5M LiPF₆+ 0.1M LiNO₃ EC:DMC:Sul olane 0.75M LiTFSI+ 0.1M LiNO₃ EC:DMC 0.75M LiTFSI+ 0.1M LiNO₃ EC:DMC:Sul olane 1M LiPF₆ EC:DMC 1:1 Figu e 1. LSV cu es o hal -cells using di e en elec oly es a he scan a e o 5 mV/s. The wo king elec ode used in he hal -cells is Al -0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 2.5 3.0 3.5 4.0 4.5 5.0 5.5 I [mA/cm2] UWE [V] 1.5M LiPF₆ EC:DMC 1:2 1.5M LiPF₆ EC:DMC:Sul olane 1:2:1 1.5M LiPF₆+ 0.1 M LiNO₃ EC:DMC 1.5M LiPF₆+ 0.1M LiNO₃ EC:DMC:Sul olane 0.75M LiTFSI+ 0.1M LiNO₃ EC:DMC 0.75M LiTFSI+ 0.1M LiNO₃ EC:DMC:Sul olane 1M LiPF₆ EC:DMC 1:1 Figu e 2. LSV cu es o hal -cells using di e en elec oly es a he scan a e o 1 mV/s. The wo king elec ode used in he hal -cells is Al The ma e ials LiNi0.5Mn1.5O4 and LiC 0.1Ni0.4Mn1.5O4 we e analysed using SEM mic oscopy. We can see s uc u es o bo h syn hesised ma e ials in Fig. 3, he ield o iew o bo h samples is 41.5 In . J. Elec ochem. Sci., Vol. 10, 2015 6292 μm. I is possible o obse e he c ys al s uc u e o syn hesized samples in bo h cases. We can see ha he c ys al size o he ma e ial LiC 0.1Ni0.4Mn1.5O4 is somewha smalle han in he ma e ial LiNi0.5Mn1.5O4. Figu e 3. SEM analysis o he samples A) LiNi0.5Mn1.5O4 and B) LiC 0.1Ni0.4Mn1.5O4 iew ield used - 41.5μm The las analysis ca ied ou on samples LiNi0.5Mn1.5O4 and LiC 0.1Ni0.4Mn1.5O4 was EDX analysis o hei composi ion. Resul s o bo h ma e ials a e shown in Fig. 4. As shown in Fig. 4-1) he dis ibu ion o elemen s in he ma e ial is uni o m and he esul ing ma e ial con ains oxygen, nickel and manganese. Fig. 4-2) shows he esul o EDX analysis o he sample LiC 0.1Ni0.4Mn1.5O4, i is again e iden ha , like in he ma e ial LiNi0.5Mn1.5O4, uni o m dis ibu ion o elemen s on he su ace o he sample was achie ed, and he e a e nickel, oxygen, manganese and ch omium. Figu e 4. Mapping o he sample o 1) LiNi0.5Mn1.5O4 A) SEM pa icles LiNi0.5Mn1.5O4 B) dis ibu ion o oxygen C) dis ibu ion o manganese D) dis ibu ion o nickel 2) LiC 0.1Ni0.4Mn1.5O4 A) SEM pa icles LiC 0.1Ni0.4Mn1.5O4 B) dis ibu ion o oxygen C) dis ibu ion o manganese D) dis ibu ion o nickel E) dis ibu ion o ch omium In . J. Elec ochem. Sci., Vol. 10, 2015 6293 The s uc u al s abili y o he ca hode ma e ials LiNi0.5Mn1.5O4 and LiC 0.1Ni0.4Mn1.5O4 was in es iga ed by he mal analysis (Fig. 5). 95 96 97 98 99 100 101 0200 400 600 800 1000 Weigh loss [%] Tempa a u e [ C] O₄ ₄ O₄ Figu e 5. TGA analysis o he samples A) LiNi0.5Mn1.5O4 and B) LiC 0.1Ni0.4Mn1.5O4 -1000 -800 -600 -400 -200 0 200 400 600 800 1000 3.8 4 4.2 4.4 4.6 4.8 5 I [mA/g] UWE [V] LiNi0.5Mn1.5O4 Mn3+ → 4+ Ni2+ → 3+ Ni3+ → 4+ Ni3+ ← 4+ Ni2+ ← 3+ Mn3+ ← 4+ a) -800 -600 -400 -200 0 200 400 600 800 3.8 4 4.2 4.4 4.6 4.8 5 I [mA/g] UWE [V] LiC 0.1Ni0.4Mn1.5O4 Mn3+ → 4+ Ni2+ → 3+ Ni3+ → 4+ C 2+ ← C 3+ Ni3+ ← 4+ Ni2+ ← 3+ Mn3+ ← 4+ b) Figu e 6. CV o a) LiNi0.5Mn1.5O4 b) LiC 0.1Ni0.4Mn1.5O4 and alence changes ongoing du ing cycling. Hal -cell whi elec oly e 1.5 M LiPF6 EC:DMC 1:2 a he scan a e o 0.5 mV/s. In . J. Elec ochem. Sci., Vol. 10, 2015 6294 TGA analysis was pe o med in he empe a u e ange om oom empe a u e o 900 °C and he empe a u e was inc eased a 10 °C/min a e. I is e iden ha he la ges weigh loss was obse ed in he ange be ween 600 °C o 900 °C. This d op o weigh is caused by losing o oxygen and li hium om he ca hode ma e ial s uc u e. [15] Ma e ial wi h C exhibi s he highes s abili y du ing hea ing. Adding o ch omium caused s abiliza ion o he s uc u e o he ca hode ma e ial which leads o a signi ican s abiliza ion o weigh in compa ison wi h he p is ine ma e ial. We can see CV o bo h ypes o high- ol age ca hode ma e ials (LiNi0.5Mn1.5O4 and LiC 0.1Ni0.4Mn1.5O4) used in combina ions wi h 1.5 M LiPF6 EC:DMC 1:2 elec oly e in Fig. 6. The peaks co esponding o he changes o alence ongoing in hese ma e ials a e isible in he cha s. The e is an e iden edox peak o abou 4 V in bo h ca hode ma e ials which is caused by he change in he alence o Mn3+ o Mn4+ and back. This peak is mo e signi ican in he case o he ma e ial LiC 0.1Ni0.4Mn1.5O4 whe e i leads o an inc ease o he 4 V discha ge pla eau. We can see edox peaks ela ed o he change o he oxida ion s a e o nickel in bo h ca hode ma e ials. In he ma e ial LiC 0.1Ni0.4Mn1.5O4, we can ano he educ ion peak co esponding o he change in he alence o ch omium a abou 4.85 V. We can see a compa ison o he wo discha ge cycles o he ma e ials LiNi0.5Mn1.5O4 and LiC 0.1Ni0.4Mn1.5O4 in Fig. 7. I is e iden om hese cu es ha he ma e ial LiC 0.1Ni0.4Mn1.5O4 has a sligh ly highe discha ge pla eau due o he inco po a ion o ch omium in i s s uc u e and i s s eepe decline due o he la ge spacing o changes in he alence o nickel. This ma e ial also shows a g ea e pla eau a 4 V. This change is also caused by ch omium doping which leads o g ea e change in he alence o manganese. These changes co espond wi h he da a ob ained by using CV. 2.5 3.0 3.5 4.0 4.5 5.0 5.5 020 40 60 80 100 120 140 UWE [V] Capaci y [mAh/g] O₄ ₄ O₄ Figu e 7. Compa ison o i s discha ge cu es o Li/LiNi0.5Mn1.5O4 (do -dash line) and Li/LiC 0.1Ni0.4Mn1.5O4 (blue line) in hal -cells a 0.5 C using he 1.5 M LiPF6 EC:DMC 1:2 elec oly e Fig. 8 shows he cycling o he ma e ial LiNi0.5Mn1.5O4 in combina ion wi h di e en elec oly es a di e en loads. I is e iden ha all ou samples achie e simila capaci ies o abou 112 In . J. Elec ochem. Sci., Vol. 10, 2015 6295 mAh / g du ing he i s 10 cycles a 0.5C and he mos s able sample seems be he elec oly e 1.5M LiPF6 EC:DMC 1:2 which eached 100.5 % o he capaci y o he i s cycle in he en h cycle. The leas s able was he sample wi h he elec oly e 1.5M LiPF6 + 0.1M LiNO3 EC:DMC:Sul olane 1:2:1 which los 2.3 % o i s capaci y in he i s cycle a e en cycles. Di e en declines o capaci y can be seen o ca hode ma e ials wi h di e en elec oly es du ing nex cycling a highe loads up o 5 C. The ma e ial LiNi0.5Mn1.5O4 wi h he elec oly e 1.5M LiPF6 EC:DMC 1:2 appea s o be he mos s able one eaching 89.2 % o he capaci y om he i s cycle a he end o cycling a 5 C (99.5 mAh/g) ollowed by he sample wi h he elec oly e 1.5M LiPF6 EC:DMC:Sul olane 1:2:1 which eached 82.2 % capaci y hus 92.1 mAh/g. I we compa e hese esul s wi h he esul s which we e epo ed in he p e ious a icle [16] we can see ha bo h he capaci y and he s abili y achie ed du ing cycling in he expe imen desc ibed in he pape a e highe han hose in he case o using a s anda d elec oly e 1M LiPF6 EC: DMC (1: 1) and he o e all esul s a e be e han he ones achie ed in he case o using sal LiBOB. We can see simila esul s in compa ison wi h he da a om he a icle [17] in his a icle he au ho again epo ed lowe capaci ies in all es ed C- a es in he case o s anda d elec oly e 1M LiPF6 EC: DMC (1: 1). In his a icle he e is also epo ed inc ease o achie ed capaci ies in he case o use o he elec oly e wi h addi ion o Sul olane bu he eached capaci y and s abili y a e again lowe han he ones achie ed in ou measu emen s. The highes dec ease was eco ded o he ma e ial wi h elec oly e LiPF6 + 1.5M 0.1M LiNO3 EC:DMC:Sul olane 1:2:1 which a he end o cycling a 5 C had 72.8 % o he capaci y om he i s cycle, hus 81.8 mAh/g. The load was a e wa ds educed again o he alue o 0.5 C. Fi e cha ge and discha ge cycles we e ca ied ou by his load, ollowed by cycling a 50 °C. 0 20 40 60 80 100 120 010 20 30 40 50 Q discha ge [mAh/g] Cycle numbe LiNi0.5Mn1.5O4 1.5M LiPF₆ EC:DMC 1:2 1.5M LiPF₆ EC:DMC:Sul olane 1:2:1 1.5M LiPF₆+ 0.1 M LiNO₃ EC:DMC 1:2 1.5M LiPF₆+ 0.1M LiNO₃ EC:DMC:Sul olane 1:2:1 0.5 C 1 C5 C 2 C2 C1 C0.5 C0.5 C -50°C Figu e 8. Compa ison o capaci y change depending on load and empe a u e changes o he ma e ial LiNi0.5Mn1.5O4 wi h di e en elec oly es In . J. Elec ochem. Sci., Vol. 10, 2015 6296 The ca hode ma e ial wi h he highes capaci y in he las cycle a 0.5 C a oom empe a u e was he one wi h he elec oly e 1.5M LiPF6 EC:DMC 1:2 ha a e o y cycles a di e en loads los 2.1 % o he capaci y om he i s cycle. I was ollowed by he sample wi h elec oly e 1.5M LiPF6 EC:DMC:Sul olane 1:2:1 which los 5.8 % o i s capaci y in compa ison wi h he i s cycle. The highes dec ease was obse ed in he sample wi h elec oly e 1.5M LiPF6 + 0.1M LiNO3 EC:DMC:Sul olane 1:2:1 which capaci y dec eased by 8.1 %. The dec ease o capaci y can be seen o all samples du ing cycling a 50 °C. This is e y signi ican o he samples wi h elec oly e con aining LiNO3 and he cell p ac ically s ops wo king. The mos s able ma e ial is he one wi h elec oly e 1.5M LiPF6 EC:DMC 1:2 whe e he dec ease o he capaci y is g adual and om he six h cycle he capaci y s abilizes. The capaci y o his sample a he end o he cycling was 88.5 % o he capaci y om he i s cycle. The cycling o he sample wi h elec oly e 1.5M LiPF6 EC:DMC:Sul olane 1:2:1 p o ided simila esul s. The capaci y was somewha lowe - i was equal o 78.4 % o he capaci y in he i s cycle a he end o cycling a 50°C. 0 20 40 60 80 100 120 140 010 20 30 40 50 Q discha ge [mAh/g] Cycle numbe LiC 0.1Ni0.4Mn1.5O4 1.5M LiPF₆ EC:DMC 1:2 1.5M LiPF₆ EC:DMC:Sul olane 1:2:1 1.5M LiPF₆+ 0.1 M LiNO₃ EC:DMC 1:2 1.5M LiPF₆+ 0.1M LiNO₃ EC:DMC:Sul olane 1:2:1 0.5 C 1 C5 C 2 C2 C1 C0.5 C0.5 C -50°C Figu e 9. Compa ison o capaci y change depending on load and empe a u e changes in ma e ials LiC 0.1Ni0.4Mn1.5O4 wi h di e en elec oly es Fig.9 shows he cycling o he ma e ial LiC 0.1Ni0.4Mn1.5O4 in combina ion wi h di e en elec oly es a di e en loads simila ly as in he case o ma e ial LiNi0.5Mn1.5O4. Ma e ial LiC 0.1Ni0.4Mn1.5O4 showed highe capaci y han LiNi0.5Mn1.5O4 du ing he i s en cycles. Thei capaci y was a ound 130 mAh/g in he case o he elec ode an elec oly e o which did no con ain he