Improved cycling performance of CeO2-inlaid Li-rich cathode materials for lithium-ion battery

Abstract The Li-rich cathode material for long cycle performance and long-term storage performance is a challenge for next-generation lithium-ion batteries due to the rapid capacity degradation over cycling and the formation of residual lithium on the surface during long-term storage. Herein, an elevated performance of Li1.2Mn0.54Ni0.13Co0.13O2 materials via CeO2 inlay is reported, which was prepared from Li1.2Mn0.54Ni0.13Co0.13O2 by sol-gel inlay with CeO2. It was proved by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy that cerium oxide cladding not only covered the surface of the material but also diffused into the interior of the material change crystal structure. Cerium oxide on the cladding not only reduces the material's contact with water and carbon dioxide in the air, but also prevents the material from being corroded by electrolyte during electrochemical test. The position of the transition metal atom is replaced Ce atoms, which increases the unit cell volume and the stability of the Li-rich material during the cycling. The results show that the storage property and the electrochemical cycling property of the material have been improved obviously. The CeO2 inlaid lithium rich material discharged 204.6 mAh/g for the first time at the current of 1C, and 164.4 mAh/g after 150 charge and discharge cycles with corresponding capacity retention rate of 80.35%, compared with the retention rate of 57.26% for pristine Li-rich material capacity. After being stored in humid air for 40 days, the CeO2 inlaid lithium-rich material showed better electrochemical performance than the pristine one. It is powerfully demonstrated that the CeO2 inlay strategy here holds huge promise for surface modification of electrode materials for lithium-ion batteries.