Engineering a Robust Interface on Ni-Rich Cathodes via a Novel Dry Doping Process toward Advanced High-Voltage Performance

Ni-rich layered oxides have become the main force of cathode materials for EV cells with high energy density owing to their satisfactory theoretical capacity, cost-effectiveness, and low toxicity. However, the high-voltage stability of Ni-rich cathode materials still has not fulfilled the demand of power batteries due to their intrinsic structural and electrochemical instability. The commonly used modification procedures are achieved via a wet process, which may lead to surface lithium-ion deficiency, phase change, and high costs during manufacturing. Herein, we construct a multifunctional Ti-based interfacial architecture on the surface of LiNi_0.6Co_0.2Mn_0.2O₂ (NCM) cathode materials via a novel dry interface modifying process in which no solvent is employed. The Ti-based interfacial architecture accelerates the transportation of lithium ions and consequently stabilizes the interfacial structure. This approach significantly improves the cycling stability in half cells, with a 15% increase in capacity retention over 100 cycles at 1 C under a high voltage of 4.5 V. Impressively, few internal cracks are observed in a modified sample after 500 times of charge and discharge between 2.75 and 4.35 V at 1 C rate, and the capacity retention can reach 93%.