Improvement of the cycling performance of LiCoO2 with assistance of cross-linked PAN for lithium ion batteries

Abstract

LiCoO2 has been widely used in lithium ion batteries for digital electronic products. However, the limited cycling performance under high cut-off voltage hinders its commercial application. Many metal oxides and/or phosphorus coating have been reported to improve the cycling performance of LiCoO2. In this paper, we report on cross-linked PAN coated LiCoO2 composite as a cathode material for lithium ion batteries. The coating layer was obtained by intermolecular crosslinking of PAN polymer chain by heat treatment at high temperature in air. The air heating process avoids the possible damage arising from the carbon thermal reduction to the surface structure of LiCoO2. Electrochemical test indicates that the LiCoO2 with the cross-linked PAN coating layer shows much improved cycle performance compared with that of bare and Al2O3 coated LiCoO2. These findings might also open new avenues to explore polymer coating for other cathode materials of lithium ion batteries.