Enhanced cycling stability and rate performance of Co‐doped and La ₂ O ₃ ‐coated LiNi _0.9 Mn _0.1 O ₂ toward power battery

Abstract

Abstract Ultra‐high nickel layered oxide cathode material with high energy density is the most promising material to improve the electrochemical performance of lithium‐ion batteries (LIBs). However, the poor structural stability and severe surface/interface side reactions of the material lead to poor rate performance and cyclic stability, which limits its application in practice. In this paper, the dual‐modification strategy of Co doping and La 2 O 3 coating is used to meet the above challenges. Co doping can effectively widen layer spacing and reduce Li + /Ni 2+ mixing, and La 2 O 3 coating can effectively eliminate the residual alkali on the surface of active material, inhibit the thickening of cathode electrolyte interphase (CEI) film and reduce surface/interface side reactions. Therefore, the modified material (NM90‐CL) with excellent electrochemical properties is achieved through the synergistic enhancement of Co doping and La 2 O 3 coating. Its capacity retention rate can reach 77.9% after 200 cycles at 1.0 °C and 75.7% after 200 cycles at 5.0 °C. Its reversible capacity can up to 153.5 mAh·g –1 at 10.0 °C. This dual‐modification strategy will provide theoretical guidance and technical support for the synthesis of other high‐performance electrode materials.