Coating material-induced acidic electrolyte improves LiCoO2 performances

The surface of commercial LiCoO2 was coated with a thin layer of amorphous YPO4 at room temperature. The structure and electrochemical and thermal performances of the surface-modified LiCoO2 were characterized by X-ray diffraction, scanning electron microscopy, and differential scanning calorimetry techniques as well as galvanostatic cycling. It is found that surface modification improves the structural and thermal stability and rate performance of LiCoO2. These improvements were attributed to the interactions between the battery materials and the Lewis acids converted from the coating material based on comprehensive analyses to the electrolyte and the electrode. (c) 2006 The Electrochemical Society.