Surface Li⁺/Ni²⁺ Antisite Defects Construction for Achieving High-Voltage Stable Single-Crystal Ni-Rich Cathode by Anion/Cation Co-Doping

Ni-rich cathode material possesses a considerable theoretical capacity, yet achieving their full capacity potential remains challenging. Elevating its operation voltage is an effective approach, while the stability of Ni-rich cathode material is relatively poor, which is limited by Li+/Ni2+ mixing. Herein, a strategy of cation/anion co-doping is proposed for single-crystal ultrahigh-nickel cathode LiNi0.92Co0.04Mn0.04O2 operated at 4.5 V. The enhancement mechanism is explicitly revealed by in situ/ex situ tests and theory calculations. Specifically, Mo6+ and F- are introduced to construct an appropriate Li+/Ni2+ antisite defects structure at the particle surface, which can maintain the low-defect Li+ layered channel inside the bulk simultaneously, inducing a stable access portal for Li+ transport from the cathode/electrolyte interface. More importantly, the Li+/Ni2+ antisite passivation layer on the surface can uphold the stability of Li-layer and optimize the reactive behavior of Ni2+, thus boosting the interfacial stability and reducing the lattice mismatch. As a result, it can achieve high capacity (204 mAh g(-1) at 1 C-degrees) and stable retention during long-term high-voltage measurements both in half-cell (87.1% after 200 cycles) and full-cell (91.9% after 400 cycles). This facile strategy provides a feasible technical reference for further exploiting the ultrahigh-capacity of Ni-rich cathode for commercial application.