Al2O3 coating on LiMn2O4 by electrostatic attraction forces and its effects on the high temperature cyclic performance

Bare LiMn2O4 was coated by a thin Al2O3 layer using electrostatic attraction forces to investigate the effects of the Al2O3 coating on the high-temperature cyclic performance of LiMn2O4. Transmission electron microscopy (TEM) studies indicated that 5-nm thin and amorphous Al2O3 layer formed uniformly on the surface of 2 wt.% Al2O3 coated LiMn2O4. The high-temperature cyclic performance of the LiMn2O4 was significantly improved by the coating. From the Electrochemical Impedance Spectroscopy (EIS) and X-ray Fluorescence (XRF) analysis, the coating reduced the charge transfer resistance and inhibited the Mn dissolution. The improved electrochemical performance of the Al2O3 coated LiMn2O4 was attributed to the decrease in the Mn dissolution by the coating.