Mechanism of capacity fade of MCMB/Li-1.1[Ni1/3Mn1/3Co1/3](0.9)O-2 cell at elevated temperature and additives to improve its cycle life

The performance degradation of graphite/Li-1.1[Ni1/3Mn1/3Co1/3](0.9)O-2 lithium-ion cells at elevated temperature was investigated. The electrochemical data suggest that the migration of dissolved transition metals from the cathode to the anode is the key contributor to the performance degradation. With the help of density function theory calculations, lithium difluoro[oxalato] borate was tested to be an effective electrolyte additive to mitigate the performance degradation of lithium-ion cells. The application of this novel electrolyte additive was found to significantly improve both the life and safety characteristics of graphite/Li-1.1[Ni1/3Mn1/3Co1/3](0.9)O-2 lithium-ion cells.