Improvement of electrochemical stability of LiMn2O4 by CeO2 coating for lithium-ion batteries

CeO2-coated LiMn2O4 spinel cathode was synthesized using two-step synthesis method. All the samples exhibited a pure cubic spinel structure without any impurities in the XRD patterns. The results of the electrochemical performances on CeO2-coated electrode are compared to those of electrodes based on LiMn2O4 spinel without CeO2 coating. CeO2-coated LiMn2O4 cathode improved the cycling stability of the electrode. The capacity retention of 2 wt% CeO2-coated LiMn2O4 was more than 82% after 150 cycles between 3.0 and 4.4 V at room temperature and 82% after 40 cycles at elevated temperature of 60 degrees C. The amounts of dissolved manganese-ions in CeO2-coated LiMn2O4 significantly are smaller than pristine LiMn2O4 systems especially at elevated temperatures. Surface-modified LiMn2O4 can suppress the dissolution reaction of manganese-ions at elevated temperature and clearly improve the cyclability of the spinel LiMn2O4 cathode materials. (c) 2006 Elsevier Ltd. All rights reserved.