Boron‐Chemistry Engineering for Sodium Layered Oxide Cathodes: From Bulk Modulation to Interfacial Reconstruction

ABSTRACT Sodium layered oxide cathodes (Na _x TMO ₂ ) are regarded as promising candidates for sodium‐ion batteries (SIBs) owing to their simple synthesis and high capacity. However, issues like irreversible phase transitions, structural degradation, sluggish Na ⁺ diffusion kinetics, and lattice oxygen instability at high voltages hinder their practical implementation. The electronic‐structure‐guided design has emerged as an effective strategy to tackle these challenges. Herein, B, with its unique electron‐deficient 1s ² 2s ² 2p ¹ configuration and low electronegativity, is chosen as a strategic nonmetal element to modulate local coordination environment and strengthen interatomic bonding. This selection facilitates the modification of Na _x TMO ₂ cathodes spanning from bulk modulation to interfacial reconstruction. B‐doping introduces strong B ─ O ─ TM bonds to suppress irreversible phase transitions and enable smooth structural evolution. Meanwhile, B‐chemistry induces interfacial reconstruction (like NaBO ₂ or Na ₂ B ₄ O ₇ derived layers) rather than forming an inert coating, which effectively protects material surface, mitigates electrolyte corrosion, and parasitic side reactions. Moreover, B‐induced interlayer expansion accelerates Na ⁺ diffusion kinetics, while the high B ─ O bond energy (809 kJ mol ⁻¹ ) stabilizes the lattice oxygen. B‐modification provides design guidelines for high‐performance SIBs. Furthermore, this review offers perspectives on using advanced techniques to deepen the mechanistic understanding and highlights the broad application prospects of SIBs in next‐generation energy storage systems.