Coupled optimization of electronic and lattice structure for sodium storage stability in layered sodium vanadate cathodes

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Layered sodium vanadate has attracted considerable attention as a promising cathode material for sodium-ion batteries, due to its multiple accessible vanadium valence states and large interlayer spacing. However, its inherent limitations in electronic/ionic conductivity and lattice stability result in poor Na + storage stability. To address these challenges, a coupled electronic and lattice modulation strategy is proposed, in which metal-ion pre-intercalation is employed to tune the electronic structure of lattice oxygen. It is revealed that Zn 2+ pre-intercalation elevates the p-band center of lattice O (Oεp) by forming the interlayer local coordination structure of ZnO 4 tetrahedral. This electronic modulation simultaneously increases both oxygen vacancy formation energy and Na + adsorption energy, leading to two critical improvements of significant suppression of potential attenuation and enhanced Na + transport kinetics. Furthermore, the Oεp position serves as a critical descriptor for Na + storage stability, exhibiting an approximately linear correlation with both average potential retention and capacity retention. Consequently, Zn 2+ pre-intercalated cathode exhibits outstanding long-term cycling stability, achieving a high capacity retention of 81.2% after 500 cycles at 1.65 A g −1 , with potential attenuation nearly eliminated. This study advances both the fundamental understanding and practical design of layered oxide cathodes through structural modification for enhanced cycling stability. • The newly developed layered sodium vanadate cathode demonstrates an outstanding capacity retention of 81.2% after 500 cycles at a high current density of 1.65 A g −1 . • Zn 2+ pre-intercalation effectively elevates the O p-band center (Oεp) by forming the interlayer local coordination structure of ZnO 4 tetrahedral. • The p-band center of lattice O (Oεp) is found to be a key descriptor for Na + storage stability, exhibiting approximate linear correlation with both average potential retention and capacity retention.

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