Novel method to enhance the cycling performance of spinel LiMn2O4

In this study, a novel method was presented to improve the cycle performance of the spinel LiMn2O4 This method is quite different from the traditional way of coating LiMn2O4 particle itself with inorganic and organic compounds. First we covered the current collector with the mixture of LiMn2O4 particle, conductive agents and binders, and then deposited an aluminum film onto it by means of vacuum evaporation. The pure electrode and the modified electrode were investigated using a combination of scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and charge-discharge tests. The enhancement of the capacity retention of modified electrode is significant, maintaining 93.5% of the maximum capacity after 200 cycles at charge-discharge rate of C/2, while pure electrode only 63.7%. It was found that the improvement of cycling performance is greatly ascribed to the good electrical conductivity of aluminum film deposited on the surface of spinel LiMn2O4. (c) 2007 Elsevier B.V. All rights reserved.