Electrochemical characterization of AlPO4 coated LiNi1/3Co1/3Mn1/3O2 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 degrees C. The electrochemical studies suggest that the initial columbic efficiency is significantly enhanced. AnNCM sample coated with 1.0 wt% AlPO4 delivers a higher discharge capacity and shows excellent capacity retention ability.

Automated summary

Aluminum phosphate coating affects the surface structure and electrochemical properties of NCM cathode material, blocking Li+ insertion-extraction process and increasing surface film resistance, while aiding in stabilizing the solid electrolyte interface film and cell resistance.