Electrochemical characterization of AlPO 4 coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode materials for high temperature lithium battery application

Aluminum phosphate (AlPO4) was used to modify the surface of LiNi1/3Co1/3Mn1/3O2 (NCM) cathode material. The surface structure and electrochemical properties of the coated materials were investigated by X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The results confirm the formation of aluminum-containing solid solution on the surface of NCM particles. An aluminum phosphate coating blocks the Li+ insertion-extraction process in cells charged at high rates at room temperature, increasing surface film resistance and decreasing discharge capacity. However, an aluminum phosphate aids the formation of a stable solid electrolyte interface film on NCM surface and stabilizes the Rct of cell as samples electrochemically cycled at 55 °C. The electrochemical studies suggest that the initial columbic efficiency is significantly enhanced. An NCM sample coated with 1.0 wt% AlPO4 delivers a higher discharge capacity and shows excellent capacity retention ability.