A Comprehensive Solution for Ni-Rich Cathodes by Lithium Silicate Coating

Abstract

Ni-rich materials are among the most promising cathode materials for use in the electric vehicle industry with high energy density, excellent low temperature performance and rate performance. However, with the increase of Ni content, many problems emerge in Ni-rich materials, such as residual alkali and the side reactions at the electrode surface. In this work, we find that part of the residual lithium at the surface of the Li[Ni0.8Co0.1Mn0.1]O2 material can be converted into lithium silicate as a lithium-ion conductor, through the surface treatment of tetraethyl orthosilicate, thereby solving the above problems. Specifically, at a rate of 3C, the material with a coating amount of 2 wt% showed a capacity retention rate of 83.33% after 300 cycles, with the pristine material at only 64.60%. Furthermore, under the protection of the coating layer, the dissolution of the transition metal and side reactions on the cathode electrode surface were effectively suppressed. Experimental results proved that this method is reliable and easy to implement and can serve as a comprehensive solution for common problems of Ni-rich materials.