2-(triphenylphosphoranylidene) succinic anhydride as a new electrolyte additive to improve high temperature cycle performance of LiMn2O4/graphite Li-ion batteries

Abstract Aiming at improving the capacity retention abilities of LiMn 2 O 4 /graphite based Li-ion batteries (LIBs) at high temperatures, we report on 2-(triphenylphosphoranylidene) succinic anhydride (TPSA) as a new electrolyte additive. The unit cells with 0.1 wt.% of TPSA achieved a 43% capacity retention increase at high temperature operation (55 °C, 100 cycles, C/2 rate) compared to a control group without the additive. To understand the underlying principle on the enhanced capacity retention ability of the unit cells, the effect of TPSA was investigated by cyclic voltammetry, X-ray photoelectron spectroscopy, auger electron spectroscopy, and galvanostatic measurements. The results suggest that the electrochemical decomposition of TPSA takes place on both surfaces of the LiMn 2 O 4 and graphite during precycling, thereby reducing the decomposition reaction of the electrolyte during subsequent cycles.