Investigation of Lithium Tetrafluorooxalatophosphate [LiPF[sub 4](C[sub 2]O[sub 4])] as a Lithium-Ion Battery Electrolyte for Elevated Temperature Performance

The thermal stability of lithium tetrafluorooxalatophosphate electrolyte was investigated. Although the thermal stabilities of the solid and were comparable, the thermal stability of the liquid /carbonate electrolyte was better than /carbonate electrolytes. Lithium-ion cells containing electrolyte had better capacity retention than electrolyte containing cells upon cycling after storage at for 2 weeks. Ex situ analysis of the electrodes before and after storage at and cycling suggested that differences in the structures of the anode and cathode surface films contributed to the superior performance of cells containing electrolyte.