Ce-modified LiNi0.5Co0.2Mn0.3O2 cathode with enhanced surface and structural stability for Li ion batteries

The well-established LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode materials possess a broad prospect for Li-ion batteries. However, the NCM523 still suffers severe capacity fading and structural instability. In this research, Ce-doped and CeO2-coated NCM523 cathode materials are synthesized by a smart one-step calcination process. It is found that the CeO2 coating layer is formed during high-temperature calcination. The CeO2 coating layers stop the electrode from being exposed to the electrolyte directly and promote the kinetics of lithium deintercalation. Besides, Ce doping could suppress the bulk cation-mixing degree. Electrochemical tests suggest that Ce-modification improves the capacity retention of cathode materials. The optimized Ce-modification cathode material, among 2.7 V and 4.6 V, not only shows the best capacity retention of 76.2%, but also delivers a discharge capacity of 178.2 mAh g−1 at 1 C. This smart modification strategy provides novel ideas for advanced LIBs.