Uniform Coating of Se on Selenophilic Surfaces of Nickel-Rich Layered Oxide Cathode Materials for High Performance Li-Ion Batteries

A novel and uniform Se coating layer on the selenophilic surface of the Ni-rich layered metal oxide (LNCM) cathode material was constructed via a facile melt-diffusion approach. The high selenophilicity of the LNCM surfaces should attribute to the strong interactions of the exposed Ni, Co, and Mn atoms with Se coating through the formation of metal-Se bonds, resulting in the conformal and homogenous deposition of Se layers. The uniform Se coating layers could not only protect the Ni-rich LNCM cathode materials from the side reaction with the electrolytes but also reduce the degree of Li+/Ni2+ cation disorder. Therefore, owing to the multifunctional effects of Se coating, the Se-coated LNCM811 cathode materials exhibit excellent cyclic stability and rate performances with a high initial capacity of 205 mA h g(-1) at 0.2 C and the high reversible capacities of 173 mA g(-1) at the 100th cycle at 0.2 C, 132 mA h g(-1) at 200th cycle at 2 C, and 103 mA h g(-1) at 300th cycle at 5 C. This present work indicates that the Se coating on the advanced Ni-rich layered metal oxide cathode material through the facile melt-diffusion approach should be promising for the high performance Li-ion battery.