Lithium manganese oxide spinel (LiMn2O4) batteries show catastrophic capacities fading after extended storage and being work at 55 degrees C. In view of electrolyte, the performance deterioration of LiMn2O4 cathode mainly origins from acidic impurity HF from the decomposition of LiPF6 salt in the presence of trace water at 55 degrees C, which is believed to accelerate electrolyte decomposition. For that reason, the effect of p-toluenesulfonyl isocyanate (PTSI) as electrolyte additive on the stability of the electrolyte and cycling performance of LiMn2O4/Li cell at 55 degrees C was studied. To verify that PTSI suppress Mn3+ dissolution mechanism of LiMn2O4 cathode, diethyl carbonate (DEC)-based electrolyte using PTSI is newly evaluated as novel film-forming electrolyte additive. Comparative analysis of the electrolyte with and without PTSI by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Based on these results, PTSI can be used as effective electrolyte additive for formation of a good solid electrolyte interphase (SEI) layer on the LiMn2O4 electrode. The capacity fading of LiMn2O4/Li cells after extended storage and being work at 55 degrees C were obviously inhibited, which is mainly originated from the suppression of carbonate solvents electrolyte decomposition and the enhancement of SEI conductivity. (C) 2015 Elsevier Ltd. All rights reserved.