Improving the Electrochemical Performance of Core-Shell LiNi0.8Co0.1Mn0.1O2 Cathode Materials Using Environmentally Friendly Phase Structure Control Process

The phase structure of the precursor is crucial for the microstructure evolution and stability of Ni-rich cathode materials. Using sodium lactate as a green complexing agent, cathode electrode materials with different phase structures and unique core-shell structures were prepared by the co-precipitation method in this study. The influence of the phase structure of the nickel-rich precursor on the cathode electrode materials was studied in depth. It was found that alpha-NCM811 had large interlayer spacing, which was beneficial for the diffusion of lithium ions. In contrast, beta-NCM811 had smaller interlayer spacing, a good layered structure, and lower ion mixing, resulting in better cycling performance. The core-shell- alpha beta-NCM811 with alpha-NCM811 as the core and beta-NCM811 as the shell was prepared by combining the advantages of the two different phases. The core-shell-alpha beta-NCM811 showed the highest discharge capacity of 158.7 mAh/g at 5 C and delivered excellent rate performance. In addition, the fi-NCM811 shell structure with smaller layer spacing could prevent corrosion of the beta-NCM811 core by the electrolyte. Thus, the capacity retention rate of the core-shell- alpha beta-NCM811 was still as high as 86.16% after 100 cycles.

Automated summary

The phase structure of the precursor plays a crucial role in the microstructure evolution and stability of Ni-rich cathode materials. In this study, cathode electrode materials with different phase structures and a unique core-shell structure were prepared using sodium lactate as a green complexing agent. The influence of the phase structure of the nickel-rich precursor on the cathode electrode materials was deeply examined. The core-shell- alpha beta-NCM811, with alpha-NCM811 as the core and beta-NCM811 as the shell, showed excellent performance in terms of discharge capacity and rate performance.