The effect of heptamethyldisilazane as additive on the stability of the electrolyte and cycling performance of LiMn2O4 batteries was studied by linear sweep voltammetry, charge–discharge of battery, stability measurement and high temperature test. The results show that the addition of heptamethyldisilazane to the electrolyte can suppress the contents of HF in the electrolyte and the cycling performance of LiMn2O4 batteries can be improved. After storage at 60°C for 7 days, the stability of batteries using electrolyte with heptamethyldisilazane can be improved, however the stability of batteries using the electrolyte with heptamethyldisilazane can be weakened after storage at 85°C for 4h.