Enhanced stability and high-rate performance of LiNi0.8Co0.1Mn0.1O2 by surface topological synthesis of rare earth polymetallic oxides coating

Abstract

The rapid capacity fading of the Ni-rich cathode has become the main obstacle to its development. Generally, the coating method can be used for modification, which can effectively isolate side reactions and maintain the original structure. In this study, novel rare earth (La, Ho, Tm) polymetallic oxide (REPMO) coating is topologically prepared on the surface of LiNi0.8Co0.1Mn0.1O2 (NCM811) by using high speed shearing with reduction method. After modification, the high-rate capacity at 5 C enhanced a lot (100.3 mA h g−1 vs 31.2 mA h g−1) which is 3.2 times higher. This is because the Ni2+ of the cathode could be changed into Ni3+ to reduce the mixing of Li+/Ni2+ and the structural stability has been improved. Moreover, the synergistic effect of REPMO coating can increase ionic conductivity, accelerate Li+ diffusion rate and inhibit the phase transition, cation mixing and volume shrinkage. Our work provides an innovative idea at this moment for the selection and synthesis method of coating material for modification of cathode material.