Manipulating Oxygen Vacancies to Spur Ion Kinetics in V 2 O 5 Structures for Superior Aqueous Zinc‐Ion Batteries

Abstract Vanadium‐based intercalation materials have attracted considerable attention for aqueous zinc‐ion batteries (ZIBs). However, the sluggish interlaminar diffusion of zinc ions due to the strong electrostatic interaction, severely restricts their practical application. Herein, oxygen vacancy‐enriched V 2 O 5 structures (Zn 0.125 V 2 O 5 ·0.95H 2 O nanoflowers, O v ‐ZVO) with expanded interlamellar space and excellent structural stability are prepared for superior ZIBs. In situ electron paramagnetic resonance (EPR) and X‐ray diffraction (XRD) characterization revealed that numerous oxygen vacancies are generated at a relatively low reaction temperature because of partially escaped lattice water. In situ spectroscopy and density functional theory (DFT) calculations unraveled that the existence of oxygen vacancies lowered Zn 2+ diffusion barriers in O v ‐ZVO and weakened the interaction between Zn and O atoms, thus contributing to excellent electrochemical performance. The Zn||O v ‐ZVO battery displayed a remarkable capacity of 402 mAh g −1 at 0.1 A g −1 and impressive energy output of 193 Wh kg −1 at 2673 W kg −1 . As a proof of concept, the Zn||O v ‐ZVO pouch cell can reach a high capacity of 350 mAh g −1 at 0.5 A g −1 , demonstrating its enormous potential for practical application. This study provides fundamental insights into formation of oxygen‐vacant nanostructures and generated oxygen vacancies improving electrochemical performance, directing new pathways toward defect‐functionalized advanced materials.