Na and Cl co-doping modified LiNi_0.5Co_0.2Mn_0.3O₂as cathode for lithium-ion battery

In recent years, ternary nickel-rich layered oxides have gradually replaced traditional binary cathode materials in the lithium-ion battery market due to their advantages of high energy density and environmental protection. However, their structural instability of cathode materials has seriously affected the cycle performance of the battery. In order to optimize the internal structure of LiNi_0.5Co_0.2Mn_0.3O₂(NCM523), the modified LiNi_0.5Co_0.2Mn_0.3O₂was prepared byin situdoping Na and Cl wet grinding solid phase method. After 80 cycles at 1 C, the capacity retention rate was 80.91%, which was higher than that of LiNi_0.5Co_0.2Mn_0.3O₂by 70.00%. Scanning electron microscopy showed that the surface corrosion of LiNi_0.5Co_0.2Mn_0.3O₂was effectively alleviated by Na and Cl co-doping. In addition, the band structure, state density and volume changes were obtained by simulation. The results show that the impedance, capacity and capacity retention data are very compatible with the simulation results. Therefore, Na and Cl doping can effectively optimize the internal structure of LiNi_0.5Co_0.2Mn_0.3O₂and improve its electrochemical performance. The combination of simulation and experiment provides a new approach for the modification of ternary cathode materials.