Enhancing LiNiO₂ cathode materials by concentration-gradient yttrium modification for rechargeable lithium-ion batteries

Lithium nickel oxide (LiNiO2) cathode materials are featured with high capacity and low cost for rechargeable lithium-ion batteries but suffer from severe interface and structure instability. Here we report that rationally designed LiNiO2 via concentration-gradient yttrium modification exhibits alleviative side reactions and improved electrochemical performance. The LiNiO2 cathode with LiYO2-Y2O3 coating layer delivers a discharge capacity of 225 mAh g(-1) with a high initial Coulombic efficiency of 93.4%. These improvements can be attributed to the formation of in-situ modified hybrid LiYO2-Y2O3 coating layer, which suppresses phase transformation, electrolyte oxidation and salt dissociation due to the formation of protective cathode electrolyte interface. The results indicate promising application of concentration-gradient yttrium coating as a facile approach to stabilize nickel-rich cathode materials. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.