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
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.
