Comparative studies on ZnO-coated and uncoated LiCoO₂ cycled at various rates and temperatures

Modification by surface coating of cathode materials is one of the preferred methods to achieve improved electrochemical performance, especially at a high-charge cut-off voltage. In this study, ZnO-coated LiCoO₂ powders were prepared by plasma-enhanced chemical vapor deposition (PE-CVD). In our previous work [1], the roles of ZnO coating in the capacity retention of LiCoO₂ during high-voltage cycling in the range of 3.0 V-4.5 V and the thermal stability of the charged LiCoO₂ electrode were investigated as a function of the coating amount. This study confirms the positive effect of ZnO coating on cyclic performances of LiCoO₂, in particular at various C-rates and operating temperatures. In addition, the structural stability of the LiCoO₂ materials coated with different amount of ZnO during cycling was investigated using cyclic voltammetry.