Implanting An Electrolyte Additive On A Single Crystal Ni-Rich Cathode Surface For Improved Cycleability And Safety

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.