Realizing Superior Cycle Stability of a Ni‐Rich Layered LiNi 0.83 Co 0.12 Mn 0.05 O 2 Cathode with a B 2 O 3 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 (B 2 O 3 ) to the surface of LiNi 0.83 Co 0.12 Mn 0.05 O 2 (NCM) cathode materials. B 2 O 3 ‐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 B 2 O 3 ‐modified NCM material benefits from the formation of B 2 O 3 coating and B 3+ doping on the surface. The B 2 O 3 coating layer that is confirmed by scanning and transmission electron microscopy can suppress surface side reactions and reduce the content of Li 2 CO 3 on the surface. The B 3+ ‐doping surface is verified by X‐ray diffraction and X‐ray photoelectron spectroscopy and triggers a reduction of a small amount of Ni 3+ to Ni 2+ . Furthermore, the combination of surface B 2 O 3 coating and B 3+ 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.