Lithium difluoro(sulfato)borate as a novel electrolyte salt for high-temperature lithium-ion batteries

Abstract High-temperature electrochemical behaviors of the novel salt named lithium difluoro(sulfato)borate (LiBF 2 SO 4 ) were studied by employment of ethylene carbonate (EC) and dimethyl carbonate (DMC) as mixed solvents. In Li/MCMB (mesophase carbon microbeads) cells at 80 °C, LiBF 2 SO 4 -EC/DMC electrolyte favourably facilitates the formation of a thermal stable, effective and conductive interface film on the surface of carbonaceous anode. Besides, in LiFePO 4 /Li cells at 80 °C, LiBF 2 SO 4 -EC/DMC electrolyte exerts several advantages, such as stable cycling performance, low polarization resistance, and good rate performance. It suggests that LiBF 2 SO 4 is an excellent candidate salt for advanced high-temperature lithium-ion batteries.