Water‐Lubricated Intercalation in V2O5·nH2O for High‐Capacity and High‐Rate Aqueous Rechargeable Zinc Batteries

Abstract Low‐cost, environment‐friendly aqueous Zn batteries have great potential for large‐scale energy storage, but the intercalation of zinc ions in the cathode materials is challenging and complex. Herein, the critical role of structural H 2 O on Zn 2+ intercalation into bilayer V 2 O 5 ·nH 2 O is demonstrated. The results suggest that the H 2 O‐solvated Zn 2+ possesses largely reduced effective charge and thus reduced electrostatic interactions with the V 2 O 5 framework, effectively promoting its diffusion. Benefited from the “lubricating” effect, the aqueous Zn battery shows a specific energy of ≈144 Wh kg −1 at 0.3 A g −1 . Meanwhile, it can maintain an energy density of 90 Wh kg −1 at a high power density of 6.4 kW kg −1 (based on the cathode and 200% Zn anode), making it a promising candidate for high‐performance, low‐cost, safe, and environment‐friendly energy‐storage devices.