ABSTRACT Aqueous batteries are gaining attention owing to their high safety and cost‐effectiveness. Among these, Zn‐based aqueous batteries excel because of Zn's low redox potential (−0.76 V vs. SHE), its abundance, and eco‐friendliness. However, despite their advantages, challenges, such as low energy density and limited cycle life limit their usage. This study addresses these issues by employing low‐crystalline V 2 O 4.86 as a cathode material, enhanced with oxygen vacancies created by controlled annealing time. The structure of low‐crystalline V 2 O 4.86 facilitates rapid structural transformation into the highly active phase Zn 3+ x (OH) 2 V 2 O 7 ·2(H 2 O). Electrochemical tests revealed a 22% capacity improvement for low‐crystalline V 2 O 4.86 (360 mAh g −1 ) over high‐crystalline V 2 O 5 (295 mAh g −1 ) at 0.8 A g −1 , attributed to the presence of active oxygen vacancies. Comprehensive structural analysis, spectroscopy, and diffusion path/barrier studies elucidate the underlying mechanisms for the first time, highlighting the potential of oxygen‐engineered V 2 O 5 . These findings indicate that electrodes engineered with oxygen vacancies offer promising insights in advancing cathode materials for high‐performance secondary battery technologies.