Suppresses Vanadium Dissolution via Superlattice Strategy for Practical Zinc‐Vanadium Batteries with Ultralong Lifespan at Low Current Density

ABSTRACT Aqueous zinc‐vanadium batteries face severe capacity decay and rapid failure, particularly at low current densities (< 1 A g ⁻¹ ), primarily due to the poor structural stability of the vanadium cathode and corrosion by highly active free water, which severely hinders their practical application. Here, we propose the superlattice vanadium oxide (Superlattice‐V ₂ O ₅ ) as a cathode material to improve the cycle stability at low current density. Its larger interlayer spacing of 21.5 Å reduces structural stress during hydrated Zn ²⁺ insertion/extraction, thus mitigating structural collapse, and effectively weakening the electrostatic interaction between Zn ²⁺ and the interlayer. Furthermore, the superlattice structure diminishes the release of highly active water molecules during the desolvation of hydrated Zn ²⁺ and increases the dissolution energy of the VO ²⁺ ion from 0.96 to 1.72 eV. These synergistic effects suppress vanadium dissolution and shuttling. Consequently, the Superlattice‐V ₂ O ₅ achieves a specific capacity of 445.1 mAh g ⁻¹ at a low current density of 0.2 A g ⁻¹ and enables vanadium shuttle‐free cycling for 750 cycles (lasting 106 days). Furthermore, the superlattice structure facilitates ion insertion into the deep regions of the high mass loading electrode, which effectively improves active material utilization, thereby achieving a stability of 2800 cycles at 0.5 A g ⁻¹ with a mass loading of 19.3 mg cm ⁻² .