Implanting an electrolyte additive on a single crystal Ni-rich cathode surface for improved cycleability and safety

Abstract

Interfacial modification is one of the most important technologies to improve the overall electrochemical properties of Ni-rich cathodes. Herein, a novel strategy of in situ planting of an electrolyte film-forming additive on a single crystal NCM811 surface is proposed by consuming the residual lithium to develop a functional Al(Li)BOB nano-layer. Different from traditional physical coating, this approach cleverly consumed the undesirable residual lithium on the NCM811 surface. The in situ grown 30–50 nm Al(Li)BOB layer on the single crystal NCM811 cathode surface contributes to its much enhanced electrochemical performances. At a high operating voltage (charge voltage limit of 4.5 V vs. Li/Li⁺), the capacity retention is greatly increased from 57.0% to 83.5% after 295 cycles. Meanwhile, the incorporation of aluminum is effective in improving the thermal stability of the Ni-rich cathode. The novel interfacial strategy by in situ implanting of an electrolyte additive is of important significance for solving the critical interfacial issue for Ni-rich cathode materials.