Effect of electrolyte additives in improving the cycle and calendar life of graphite/Li1.1[Ni1/3Co1/3Mn1/3]0.9O2 Li-ion cells

Lithium-rich layered metal oxide Li1.1[Ni1/3Co1/3Mn1/3]0.9O2 was investigated as a potential positive electrode material for high-power batteries for hybrid electric vehicle (HEV) applications. In order to evaluate the power and life characteristics of the graphite/Li1.1[Ni1/3Co1/3Mn1/3]0.9O2 cell chemistry, hybrid pulse power characterization (HPPC) and accelerated calendar life tests were conducted on several pouch cells containing electrolytes with and without additives. The data show that the cells containing 0.5 wt% lithium bis(oxalate)borate (LiBOB) or vinyl ethyl carbonate (VEC) additives, or the novel lithium difluoro(oxalato)borate (LiDFOB) additive, have much improved cycle and calendar life performance.