Enhanced Cycling Stability of Lithium‐Rich Cathode Materials Achieved by in‐situ Formation of LiErO2 Coating

Abstract

AbstractLithium‐rich manganese‐based cathode materials are considered ideal for the next‐generation lithium‐ion power batteries due to their high specific capacity. However, their widespread commercial deployment has received serious limitations, such as low initial coulombic efficiency (ICE), severe voltage and capacity degradation. To solve these issues, the surface of Li‐rich layered oxide (LLO) material is uniformly coated with a layer of ternary lithium‐rare earth oxides LiErO2 by synchronous lithium strategy. The LiErO2‐coated material exhibits higher capacity retention of 83.79 % with 182.7 mAh g−1 compared with that of the pristine material, which retained 60.54 % with 144.1 mAh g−1 after 200 cycles at 0.5 C. The excellent electrochemical performance is owing to the high Li+ conductivity of the LiErO2 coating which enhanced the lithiation kinetics of the material, and X‐ray photoelectron spectrometer (XPS) results indicate coating layer has abundant oxygen vacancies that facilitate reversible redox processes of oxygen. Meanwhile, the results of high resolution transmission electron microscope (HRTEM) and XPS analyses of the materials after cycling shows the uniform coating can suppress the side reactions between the electrode and electrolyte during long‐term cycling, reduce the phase transition of the surface structure, and enhance interfacial stability. This work provides innovative ideas for the design of lithium‐rich cathode materials.