Anion Coordination Field Enables Ni/Mn Spin‐Orbital Reconstruction for Stable High‐Voltage Sodium Layer‐Structured Cathodes

ABSTRACT Ni/Mn‐based O3‐typed layer‐structured oxides are attractive for high‐voltage cathodes toward sodium batteries; however, the deep‐desodiation stability is constrained by transition‐metal orbital instability and localized oxygen redox. The anion‐coordination local‐electronic network was thus reconstructed in single‐crystalline Na[Ni 0.3 Mn 0.5 Cu 0.1 Ti 0.1 ]O 2 through a polyvinylpyrrolidone‐assisted mild nitridation strategy. The resulting Ni‐N‐Mn coordination can enhance Ni/Mn 3 d ‐N 2 p orbital coupling, driving Ni‐to‐Mn charge redistribution and stabilizing the low‐spin Mn 3+ ‐like states by increasing local crystal‐field splitting. This coordination‐induced spin/orbital reconstruction can further generate an extended TM‐(O,N)‐TM p‐d charge network that disperses high‐voltage ligand holes and stabilizes lattice oxygen. The modified cathode delivers reduced polarization, improved Na + ‐transport kinetics, and a durable cycling lifespan at high voltage, with 91% capacity retention after 300 cycles at 2 C coupled with hard carbon. These findings demonstrate anion‐coordination reconstruction as a direct route to regulating orbital occupation and oxygen redox in high‐voltage layer‐structured cathodes.