Simultaneous Regulating the Surface, Interface, and Bulk via Phosphating Modification for High-Performance Li-Rich Layered Oxides Cathodes

Li-rich Mn-based layered oxides (LRMOs) are regarded as the leading cathode materials to overcome the bottleneck of higher energy density. Nevertheless, they encounter significant challenges, including voltage decay, poor cycle stability, and inferior rate performance, primarily due to irreversible oxygen release, transition metal dissolution, and sluggish transport kinetics. Moreover, traditionally single modification strategies do not adequately address these issues. Herein, an innovative “all-in-one” modification strategy is developed, simultaneously regulating the surface, interface, and bulk via an in-situ gas–solid interface phosphating reaction to create P-doped Li_1.2Mn_0.54Ni_0.13Co_0.13O₂@Spinel@Li₃PO₄. Specifically, Li₃PO₄ surface coating layer shields particles from electrolyte corrosion and enhances Li⁺ diffusion; in-situ constructed spinel interfacial layer reduces phase distortion and suppresses the lattice strain; the strong P─O bond derived from P-doping stabilizes the lattice oxygen frame and inhibits the release of O₂, thereby improving the reversibility of oxygen redox reaction. As a result, the phosphatized LRMO demonstrates an exceptional capacity retention of 82.1% at 1C after 300 cycles (compared to 50.8% for LRMO), an outstanding rate capability of 170.5 mAh g⁻¹ at 5C (vs 98.9 mAh g⁻¹ for LRMO), along with excellent voltage maintenance and thermostability. Clearly, this “all-in-one” modification strategy offers a novel approach for high-energy-density lithium-ion batteries.