Roles of Al-doped ZnO (AZO) modification layer on improving electrochemical performance of LiNi1/3Co1/3Mn1/3O2 thin film cathode

Al-doped ZnO (AZO) was sputtered on the surface of LiNi1/3Co1/3Mn1/3O2 (NCM) thin film electrode via radio frequency magnetron sputtering, which was demonstrated to be a useful approach to enhance electrochemical performance of thin film electrode. The structure and morphology of the prepared electrodes were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer, and transmission electron microscopy techniques. The results clearly demonstrated that NCM thin film showed a strong (104) preferred orientation and AZO was uniformly covered on the surface of NCM electrode. After 200 cycles at 50 mu A mu m(-1) cm(-2), the NCM/AZO-60s electrode delivered highest discharge capacity (78.1 mu Ah mu m(-1) cm(-2)) compared with that of the NCM/AZO-120s electrode (62.4 mu Ah mu m(-1) cm(-2)) and the bare NCM electrode (22.3 mu Ah mu m(-1) cm(-2)). In addition, the rate capability of the NCM/AZO-60s electrode was superior to the NCM/AZO-120s and bare NCM electrodes. The improved electrochemical performance can be ascribed to the appropriate thickness of the AZO coating layer, which not only acted as HF scavenger to keep a stable electrode/electrolyte interface but also reduced the charge transfer resistance during cycling.