Gradient Concentration Refilling of N Stabilizes Oxygen Vacancies for Enhanced Zn2+ Storage

Abstract The introduction of oxygen vacancies into aqueous zinc ion battery (ZIB) cathodes can significantly improve the diffusion kinetics of Zn 2+ , endowing enhanced electrochemical performance. However, the stability of oxygen vacancies in batteries during aqueous electrolyte cycling has been overlooked. Here, the oxygen vacancy is stabilized by the refilling of different impurity atoms, and gradient concentration refilling of N achieves the most stable state of the oxygen vacancy with minimum formation energy (4.77 eV). The obtained Zn 3 V 2 O 7 (OH) 2 ·2H 2 O with gradient N refilling of partial oxygen vacancies (N‐V O ‐ZVO) achieves more stable oxygen vacancies and a low Zn 2+ diffusion energy barrier (0.19 eV) with an ultra‐high rate performance of 186 mAh g −1 at 100 A g −1 and capacity retention rate of 84.9% after 10 000 cycles.