Grafting a Polymer Coating Layer onto Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ Cathode by Benzene Diazonium Salts to Facilitate the Cycling Performance and High‐Voltage Stability

Abstract Li‐rich Mn‐based cathodes have been regarded as promising cathodes for lithium‐ion batteries because of their low cost of raw materials (compared with Ni‐rich layer structure and LiCoO₂ cathodes) and high energy density. However, for practical application, it needs to solve the great drawbacks of Li‐rich Mn‐based cathodes like capacity degradation and operating voltage decline. Herein, an effective method of surface modification by benzene diazonium salts to build a stable interface between the cathode materials and the electrolyte is proposed. The cathodes after modification exhibit excellent cycling performance (the retention of specific capacity is 84.2% after 350 cycles at the current density of 1 C), which is mainly attributed to the better stability of the structure and interface. This work provides a novel way to design the coating layer with benzene diazonium salts for enhancing the structural stability under high voltage condition during cycling.