Mixed Salts of LiFSI and LiODFB for Stable LiCoO₂-Based Batteries

Abstract

Mixed salts of lithium bis(fluorosulfonyl)imide Li[N(SO2F)2] (LiFSI) and Lithium difluoro(oxalato)borate (LiODFB) were used to improve excellent long-term cycling stability of Lithium cobaltate (LiCoO2)-based batteries and substituted the Lithium hexafluorophosphate (LiPF6) salt in non-aqueous electrolytes. SEM and CV demonstrated that adding LiODFB into LiFSI-based electrolytes could restrain aluminum corrosion caused by LiFSI-based electrolytes. Compared to LiCoO2-based batteries using LiPF6-based electrolytes, the cycling stability and rate capability of LiCoO2-based batteries using LiFSI0.7-LiODFB0.3-based electrolytes were excellent.