Effect of methylene methanedisulfonate as an additive on the cycling performance of LiMn2O4 cathode at elevated temperature

In order to overcome the capacity fading of LiMn2O4 cathode lithium-ion batteries (LIBs) cycled at elevated temperature, methylene methanedisulfonate (MMDS) is newly evaluated as an electrolyte additive. With the addition of 0.5 wt.% MMDS into the electrolyte (1.0 M LiPF6-EC/DMC/EMC), the capacity retention of the LiMn2O4/Li cell cycled at 55 °C is significantly increased from 51.6% to 72.8% after 200 cycles, showing the promising prospect in the electrolyte. In addition, the results of electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscopy (TEM) demonstrate that a thin and good conductive film can be formed on the LiMn2O4 surface ascribed to MMDS additive, which resulting the suppression of the electrolyte oxidized decomposition, the improvement of SEI conductivity and a good ability of Li+ migration.