Synthesis and electrochemical characteristics of Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials for lithium ion batteries

LiNi1/3Co1/3Mn1/3O2 cathode materials have been coated with Al2O3 nano-particles using sol-gel processing to improve its electrochemical properties. The X-ray diffraction (XRD) pattern of the as-prepared Al2O3 nano-particles was indexed to the cubic structure of the gamma-Al2O3 phase and had an average size of similar to 4 nm. The XRD showed that the structure of LiNi1/3Co1/3Mn1/3O2 was not affected by the A1203 coating. However, the A1203 coatings on LiNi1/3Co1/3Mn1/3O2 improved the cyclic life performance and rate capability without decreasing its initial discharge capacity. These electrochemical properties were also compared with those of LiAlO2-coated LiNi1/3Co1/3Mn1/3O2 cathode material. The electrochemical impedance spectroscopy (EIS) was studied to understand the enhanced electrochemical properties of the Al2O3-coated LiNi1/3CO1/3Mn1/3O2 compared to uncoated LiNi1/3Co1/3Mn1/3O2, (c) 2006 Elsevier Ltd. All rights reserved.