Comparative Study of the Electrochemical Behaviors for LiCoO2 Electrode Coated with Two Different Al2O3 Coating Layer

The two samples of coated LiCoO2 electrode with different microstructures of Al2O3 coating layer are prepared. The XRD, SEM and TEM results reveal that both Al2O3 coating layers attached on the surface of LiCoO2 have different uniformity, thickness, morphology and crystallinity. The charge-discharge cycling results show different initial discharge capacity and cycle ability for both Al2O3-coated LiCoO2 samples. The reasons causing electrochemical performance difference are ascribed to some following aspects: the different microstructure of both Al2O3 coating layer poses to the distrinct interface resistance, which may lead to the different transport ability of Li ions as well as electrons through Al2O3 coating layer. And meantime, the electrolyte penetration to the Al2O3 coating is also different, which pose to different side reaction on the interface between cathode and electrolyte for both samples.