Surface engineering for high stable lithium-rich manganese-based cathode materials

Lithium-rich manganese-based material shows great potential as the high specific cathode materials due to its low cost, environmental friendliness, high operating voltage and simple preparation process. However, the poor capacity retention and cycling performance caused by its unstable structure during cycling restrict the commercialization. In this work, Li1.2Ni0.16Mn0.56Co0.08O2 was synthesized utilizing a Co-precipitation method and different amount of La(PO3)3 (La(PO3)3 = 2 wt%, 4 wt% and 6 wt%) was selected as the coating layer to resolve the above issues. During the calcination process, La(PO3)3 reacts with impurities such as LiOH and Li2CO3 on the lithium-rich surface to reduce the residual lithium on the surface, thus improving the interfacial stability, slowing down the corrosion of the electrolyte, and finally enhancing its electrochemical performance. The cathode materials coated with 4% of La(PO3)3 showed the best electrochemical performance in terms of capacity retention and cycling performance compared to the pristine NCM. The high initial discharge capacity of 214.21 mAh/g and capacity retention of 94.2% after 100 cycles at 0.1 C can be obtained. This work provides an effective strategy to protect the cathode from corrosion and will promote its further practical applications in high specific Li-ion batteries.