Realizing Superior Cycle Stability of a Ni-Rich Layered LiNi0.83Co0.12Mn0.05O2 Cathode with a B2O3 Surface Modification

Ni-rich cathode is considered a promising cathode for its high specific capacity. However, a sharp capacity attenuation induced by interface problems limits the application of the cathode material. Herein, we propose a practical surface modification strategy by introducing diboron trioxide (B2O3) to the surface of LiNi0.83Co0.12Mn0.05O2 (NCM) cathode materials. B2O3-modified NCM shows superior cyclic stability with a capacity retention of 87.7 % at 1 C after 200 cycles in comparison to 69.4 % for a bare NCM. On the basis of material and electrochemical characterizations, we conclude that the superior cycle stability of B2O3-modified NCM material benefits from the formation of B2O3 coating and B3+ doping on the surface. The B2O3 coating layer that is confirmed by scanning and transmission electron microscopy can suppress surface side reactions and reduce the content of Li2CO3 on the surface. The B3+-doping surface is verified by X-ray diffraction and X-ray photoelectron spectroscopy and triggers a reduction of a small amount of Ni3+ to Ni2+. Furthermore, the combination of surface B2O3 coating and B3+ doping inhibits the irreversible phase transitions and extension of microcracks in the NCM material. The above surface modification strategy provides a direction for the acquisition of long-life cathode materials.