Solid-state polymer electrolytes(SPEs)have attracted increasing attention due to good interfacial contact,light weight,and easy manufacturing.However,the practical application of SPEs such as the most widely studied p...Solid-state polymer electrolytes(SPEs)have attracted increasing attention due to good interfacial contact,light weight,and easy manufacturing.However,the practical application of SPEs such as the most widely studied poly(ethylene oxide)(PEO)in high-energy solid polymer batteries is still challenging,and the reasons are yet elusive.Here,it is found that the mismatch between PEO and 4.2 V-class cathodes is beyond the limited electrochemical window of PEO in the solid Li Ni_(1/3)Mn_(1/3)Co_(1/3)O_(2)(NMC)-PEO batteries.The initial oxidation of PEO initiates remarkable surface reconstruction of NMC grains in solid batteries that are different from the situation in liquid electrolytes.Well-aligned nanovoids are observed in NMC grains during the diffusion of surface reconstruction layers towards the bulk in solid batteries.The substantial interphasial degradation,therefore,blocks smooth Li+transport across the NMC-PEO interface and causes performance degradation.A thin yet effective Li F-containing protection layer on NMC can effectively stabilize the NMC-PEO interface with a greatly improved lifespan of NMC|PEO|Li batteries.This work deepens the understanding of degradations in high-voltage solid-state polymer batteries.展开更多
Although the operating mechanism of sodium-ion battery(SIB)resembles that of lithium-ion battery,common film-forming additive for lithium-ion battery does not play its role in SIB.Therefore,it is essential to tailor n...Although the operating mechanism of sodium-ion battery(SIB)resembles that of lithium-ion battery,common film-forming additive for lithium-ion battery does not play its role in SIB.Therefore,it is essential to tailor new additives for SIB.Hard carbon(HC),as the most used anode material of SIB,has the disadvantage of interphasial instability,especially under the condition of long-term cycling.The incessant accumulation of electrolyte decomposition products leads to a significant increase in interphasial impedance and a sharp decline in discharge capacity.In this work,N-phenyl-bis(trifluoromethanesulfonimide)(PTFSI)was proposed as a novel film-forming electrolyte additive,which effectively enhances the long-term cycling performance for HC anode in SIB.The passivation film generated from the preferential reduction of PTFSI improves the capacity retention of HC/Na half-cell from 0%to 68%after 500 cycles.Profoundly,the enhanced interphasial stability of HC anode results in a 52%increase in capacity retention of HC/Na_(3)V_(2)(PO_(4))_(3)full-cells after 100 cycles.展开更多
The non-flammability and high oxidation stability of sulfolane(SL)make it an excellent electrolyte candidate for lithium-ion batteries(LIBs).However,its incompatibility with graphitic anode prevents the realization of...The non-flammability and high oxidation stability of sulfolane(SL)make it an excellent electrolyte candidate for lithium-ion batteries(LIBs).However,its incompatibility with graphitic anode prevents the realization of these advantages.To understand how this incompatibility arises on molecular level so that it can be suppressed,we combined theoretical calculation and experimental characterization and reveal that the primary Li^(+) solvation sheath in SL is depleted of fluorine source.Upon reduction,SL in such fluorine-poor solvation sheath generates insoluble dimer with poor electronic insulation,hence leading to slow but sustained parasitic reactions.When fluorine content in Li^(+)-SL solvation sheath is increased via salt concentration,a high stability LiF-rich interphase on graphite can be formed.This new understanding of the failure mechanism of graphite in SL-based electrolyte is of great significance in unlocking many possible electrolyte solvent candidates for the high-voltage cathode materials for next-generation LIBs.展开更多
The conventional perspective suggests that low-concentration electrolytes(LCEs)face challenges in achieving stable charge/discharge properties due to the decreased ionic conductivity resulting from lower Li^(+) concen...The conventional perspective suggests that low-concentration electrolytes(LCEs)face challenges in achieving stable charge/discharge properties due to the decreased ionic conductivity resulting from lower Li^(+) concentrations.However,the successful utilization of LCEs in lithium/sodium-ion batteries has brought them into the forefront of consideration for high performance battery systems.It is possible to achieve improved interface stability and ion transport performance for LCEs through adjusting electrolyte components,such as salts,solvents,and additives.This review provides timely update of the recent research progress,design strategies and remaining challenges of LCEs to answer several questions:i)What is the key factor for designing LCEs?ii)How to balance the low salt concentration and good ionic conductivity?iii)What is the interphasial mechanism of anode/cathode in LCEs?Firstly,the development of LCEs is discussed with typical examples.Subsequently,effectiveness of solvents on overall performances of LCEs is comprehensively summarized in detail.Finally,the challenges and possible research direction of LCEs are discussed.This review provides critical guidance for designing novel electrolytes for secondary batteries.展开更多
基金supported by the National Natural Science Foundation of China (U21A2075, 22179117)the Fujian Science & Technology Innovation Laboratory for Energy Devices of China (21CLAB) (21C-OP-202107)the Program of Zhejiang University and Program of State Key Laboratory of Clean Energy Utilization at Zhejiang (ZJUCEU2020005)
文摘Solid-state polymer electrolytes(SPEs)have attracted increasing attention due to good interfacial contact,light weight,and easy manufacturing.However,the practical application of SPEs such as the most widely studied poly(ethylene oxide)(PEO)in high-energy solid polymer batteries is still challenging,and the reasons are yet elusive.Here,it is found that the mismatch between PEO and 4.2 V-class cathodes is beyond the limited electrochemical window of PEO in the solid Li Ni_(1/3)Mn_(1/3)Co_(1/3)O_(2)(NMC)-PEO batteries.The initial oxidation of PEO initiates remarkable surface reconstruction of NMC grains in solid batteries that are different from the situation in liquid electrolytes.Well-aligned nanovoids are observed in NMC grains during the diffusion of surface reconstruction layers towards the bulk in solid batteries.The substantial interphasial degradation,therefore,blocks smooth Li+transport across the NMC-PEO interface and causes performance degradation.A thin yet effective Li F-containing protection layer on NMC can effectively stabilize the NMC-PEO interface with a greatly improved lifespan of NMC|PEO|Li batteries.This work deepens the understanding of degradations in high-voltage solid-state polymer batteries.
基金supported by the National Natural Science Foundation of China(No.21972049)the Guangdong Program for Distinguished Young Scholar(No.2017B030306013).
文摘Although the operating mechanism of sodium-ion battery(SIB)resembles that of lithium-ion battery,common film-forming additive for lithium-ion battery does not play its role in SIB.Therefore,it is essential to tailor new additives for SIB.Hard carbon(HC),as the most used anode material of SIB,has the disadvantage of interphasial instability,especially under the condition of long-term cycling.The incessant accumulation of electrolyte decomposition products leads to a significant increase in interphasial impedance and a sharp decline in discharge capacity.In this work,N-phenyl-bis(trifluoromethanesulfonimide)(PTFSI)was proposed as a novel film-forming electrolyte additive,which effectively enhances the long-term cycling performance for HC anode in SIB.The passivation film generated from the preferential reduction of PTFSI improves the capacity retention of HC/Na half-cell from 0%to 68%after 500 cycles.Profoundly,the enhanced interphasial stability of HC anode results in a 52%increase in capacity retention of HC/Na_(3)V_(2)(PO_(4))_(3)full-cells after 100 cycles.
基金supported by the National Natural Science Foundation of China(21972049)the Guangdong Program for Distinguished Young Scholar(2017B030306013)the Science and Technology Planning Project of Guangdong Province(2017B090901020)。
文摘The non-flammability and high oxidation stability of sulfolane(SL)make it an excellent electrolyte candidate for lithium-ion batteries(LIBs).However,its incompatibility with graphitic anode prevents the realization of these advantages.To understand how this incompatibility arises on molecular level so that it can be suppressed,we combined theoretical calculation and experimental characterization and reveal that the primary Li^(+) solvation sheath in SL is depleted of fluorine source.Upon reduction,SL in such fluorine-poor solvation sheath generates insoluble dimer with poor electronic insulation,hence leading to slow but sustained parasitic reactions.When fluorine content in Li^(+)-SL solvation sheath is increased via salt concentration,a high stability LiF-rich interphase on graphite can be formed.This new understanding of the failure mechanism of graphite in SL-based electrolyte is of great significance in unlocking many possible electrolyte solvent candidates for the high-voltage cathode materials for next-generation LIBs.
基金financially supported by the National Natural Science Foundation of China(No.22209106)Shanghai Pujiang Program(21PJ1408700)+1 种基金the National Key Research and Development Program of China(2022YFB2402300)supported by the Assistant Secretary for Energy Efficiency and Renewable Energy(EERE),Vehicle Technology Office(VTO)of the US Department of Energy(DOE)through the Advanced Battery Materials Research(BMR)Program under contract no.DE-SC0012704.
文摘The conventional perspective suggests that low-concentration electrolytes(LCEs)face challenges in achieving stable charge/discharge properties due to the decreased ionic conductivity resulting from lower Li^(+) concentrations.However,the successful utilization of LCEs in lithium/sodium-ion batteries has brought them into the forefront of consideration for high performance battery systems.It is possible to achieve improved interface stability and ion transport performance for LCEs through adjusting electrolyte components,such as salts,solvents,and additives.This review provides timely update of the recent research progress,design strategies and remaining challenges of LCEs to answer several questions:i)What is the key factor for designing LCEs?ii)How to balance the low salt concentration and good ionic conductivity?iii)What is the interphasial mechanism of anode/cathode in LCEs?Firstly,the development of LCEs is discussed with typical examples.Subsequently,effectiveness of solvents on overall performances of LCEs is comprehensively summarized in detail.Finally,the challenges and possible research direction of LCEs are discussed.This review provides critical guidance for designing novel electrolytes for secondary batteries.
