Surface of LiCo1/3Ni1/3Mn1/3O2 modified by CeO2-coating

A novel method to improve the cycling performance of LiCo1/3Ni1/3Mn1/3O2 in lithium-ion batteries by 1.0 wt.% CeO2-coating is presented in this work. The crystalline structure and morphology of the synthesized powder have been characterized by XRD, SEM, TEM and their electrochemical performances were evaluated by CV, EIS and galvonostatic charge/discharge tests. It is found that CeO2 forms a layer on the surface of LiCo1/3Ni1/3Mn1/3O2 without destroying the crystal structure of the core material. Electrochemical test indicates that CeO2-coating could improve the cycling performance of LiCo1/3Ni1/3Mn1/3O2. At room temperature, the capacity retention of 1.0 wt.% CeO2-coated material is 93.2% after 12 cycles at 3.0 C while that of the bare sample is only 86.6%. ICP-OES proves the coating layer could protect the dissolution of the transition metal ions from LiCo1/3Ni1/3Mn1/3O2. From the analysis of EIS, the improvement of cycle ability could be attributed to the suppression of the reaction between cathode and electrolyte. (C) 2009 Elsevier Ltd. All rights reserved.