Enhanced Electrochemical Performance of LiNi_0.8Co_0.1Mn_0.1O₂ Cathode Materials by Al₂O₃ Coating

The Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) is considered as a promising high capacity (more than 160 mAh/g) cathode for lithium-ion batteries. However, NCM811 suffers the rapid capacity fading and potential safety hazard during cycling, which hinders further commercial application. Herein, a homogeneous Al₂O₃ film is successfully coated on the NCM811 surface by the liquid phase deposition. The Al₂O₃ coating layer is evidenced by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results clearly demonstrate that the Al₂O₃ film is uniformly covered on the NCM811. In particular, the 2 wt% Al₂O₃-coated materials delivers a high discharge capacity of 162.2 mAh/g and with retention of 82.67% after 100 cycles at 0.5 C than that of the pristine NCM811 electrode with retention of 64.90% and discharge capacity of 111.50 mAh/g. The improved electrochemical performance can be ascribed to the thin and dense coating layer not only effectively inhibits the direct contact between the material and the electrolyte but also promotes the transfer of Li⁺ in the layered structure material.