Enhanced structure stability and electrochemical performance of LiNiO2 by Li2SeO4 coating and gradient surface SeO32−/ SeO42− doping

LiNiO2 has gained much attention due to its high capacity and low cost. However, rapid capacity decay due to structural degradation limits the application of LiNiO2. Herein, a fast ionic conductor Li2SeO4 coating and gradient surface SeO32−/ SeO42− doping are simultaneously achieved by consuming the residual lithium on the LiNiO2's surface. The synergistic effect of the Li2SeO4 coating and the gradient surface SeO32−/ SeO42− doping significantly stabilizes the interface and bulk phase structure and promotes Li+ ions diffusion. Therefore, the double-modified LiNiO2 delivers a capacity of 112 mAh g−1 at 10C (90 mAh g−1 for the pristine LiNiO2) and maintains capacity retention of 91 % (73 % for the pristine LiNiO2) after 100 cycles at 0.5C. Our work provides a novel strategy to improve structural stability and electrochemical performance, which is significant in developing high-performance LiNiO2.