A tiny amount of electrode additive breaks the dilemma of achieving high energy density and fast charging lithium-ion battery cathode

It is crucial to achieve high energy density and fast charging simultaneously for automotive lithium-ion batteries. The nickel-rich layered oxide LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode enables high energy density due to its high theoretical capacity and high working voltage. However, the fast charging performance is compromised because the electrode-electrolyte interface kinetics deteriorates when working at high voltage. A new approach is proposed to solve this dilemma, where [60] Fullerenoacetic acid (C₆₀-COOH) is used to tune the interface structure of the NCM811. The carboxylic acid functional group ensures preferential deposition of C₆₀ onto the NCM811 surface through the reaction with the surface residual alkaline species/transition metals. An electronic and ionic conductive thin coating layer is formed on the NCM811 surface, which inhibits electrolyte decomposition and facilitates formation of high voltage stable cathode electrolyte interface. With 0.50 wt.‰ of C₆₀-COOH, the NCM811 cathode exhibits significantly improved electrochemical performance at 4.6 V in terms of reversible capacity, and capacity retention ratio, where an exceptional fast charging/discharging performance at 10 C is demonstrated as well. This work is of great significance for promoting high energy density and fast charging automotive lithium-ion batteries.