Water-Lubricated Intercalation in V O ·nH O for High-Capacity and High-Rate Aqueous Rechargeable Zinc Batteries.

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 O on Zn intercalation into bilayer V O ·nH O is demonstrated. The results suggest that the H O-solvated Zn possesses largely reduced effective charge and thus reduced electrostatic interactions with the V O framework, effectively promoting its diffusion. Benefited from the "lubricating" effect, the aqueous Zn battery shows a specific energy of ≈144 Wh kg at 0.3 A g . Meanwhile, it can maintain an energy density of 90 Wh kg at a high power density of 6.4 kW kg (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.