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.