Interlinking Primary Grains with Lithium Boron Oxide to Enhance the Stability of LiNi_0.8Co_0.15Al_0.05O₂

Destructive effects of surface lithium residues introduced in synthesis and degradation of the microstructure and electrode/electrolyte interface during cycling of Ni-rich cathode materials are the major problems hindering their wide application. Herein, we demonstrate an exquisite surface modification strategy that can utilize lithium residues on the surface of LiNi0.8Co0.15Al0.05O2 to form a uniform coating layer of lithium boron oxide on the surface of the material. The resulting lithium boron oxide layer can not only efficiently serve as a protective layer to alleviate the side reactions at the electrode/electrolyte interface but also tightly interlink the primary grains of the LiNi0.8Co0.15Al0.05O2 material to prevent the material from degradation of the microstructure. As a result, the optimized lithium boron oxide-coated LiNi0.8Co0.15Al0.05O2 material exhibits a high initial discharge capacity of 202.1 mAh g–1 at 0.1 C with a great capacity retention of 93.59% after 100 cycles at 2 C. Thus, the uniform lithium boron oxide coating endows the NCA material with excellent structural stability and long-term cycling capability.