Heterointerface‐Regulated Deep Charging in Vanadium Oxides for Aqueous Zinc‐Ion Batteries With Wide Voltage Window

ABSTRACT Vanadium‐based cathodes in aqueous zinc‐ion batteries are generally considered unstable at wide voltage windows due to structural dissolution and interfacial side reactions, which limit reversibility under deep‐charging conditions. To address whether deep charging leads to irreversible structural changes, we construct a core‐shell vanadium‐based oxide material (FeVO) using a one‐step hydrothermal strategy, enabling stable operation over a 0.2–1.8 V voltage window. The FeVO cathode delivers a high capacity of ∼500 mAh g −1 at 0.1 A g −1 and retains 66% of its capacity after 1200 cycles at 5 A g −1 within a wide voltage window of 0.2–1.8 V. Structural and electrochemical analyses show that deep charging activates a cooperative response within the Fe‐V‐O framework, while the energy‐storage mechanism remains governed by reversible Zn 2+ /H + co‐insertion. Fe incorporation stabilizes the wide‐voltage‐window reaction pathway, suppresses side reactions, and promotes Zn 2+ diffusion, redefining the intrinsic reaction nature of vanadium‐based cathodes under deep‐charging conditions and provides a mechanistic framework for designing deep charging‐discharging aqueous zinc‐ion battery cathodes.