Li─P─F─O Bonding Topology Governs Oxygen Redox and Interfacial Stability in High‐Rate LRMO‐Based All‐Solid‐State Lithium Batteries

ABSTRACT Lithium‐rich manganese‐based oxides (LRMO) derive high capacity from lattice‐oxygen redox, but oxygen release at high voltage oxidizes solid electrolytes and drives rapid interfacial resistance growth. Nanosizing improves solid‐state kinetics yet exposes more under‐coordinated surface oxygen, aggravating interfacial degradation. Here, density functional theory screening identifies phosphate as the most effective oxyanion motif for stabilizing surface oxygen. Guided by this insight, a Li─P─F─O bonding topology is constructed through a one‐step mechanochemical reaction between LRMO and LiPO 2 F 2 . This process simultaneously refines the particles, introduces near‐surface fluorine, and forms a conformal amorphous interphase featuring P─O, P─F, and Li─F bonding environments. P–O coordination stabilizes surface oxygen, delocalizes oxidation holes, and suppresses O─O coupling, while near‐surface fluorine widens the Li layers and facilitates Li + transport. Together, these effects suppress oxygen loss, electrolyte oxidation, impedance growth, and interfacial contact failure. The modified cathode delivers 248.5 mAh g −1 at 25°C and 268 mAh g −1 at 60°C (0.1 C), retains 85% capacity after 2000 cycles at 10 C, and operates up to 16 000 cycles. A high‐loading lithium‐metal pouch cell achieves 212 mAh g −1 with specific energy of 277 Wh kg −1 . This work demonstrates bonding‐topology regulation as an effective strategy for stabilizing oxygen redox in solid‐state batteries.