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

TLDR

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 H₂O on Zn²⁺ intercalation into bilayer V₂O₅·nH₂O is demonstrated. The H₂O‑solvated Zn²⁺ exhibits a reduced effective charge that weakens electrostatic interactions with the V₂O₅ framework, enhancing diffusion and enabling the aqueous Zn battery to deliver ≈144 Wh kg⁻¹ at 0.3 A g⁻¹ and maintain 90 Wh kg⁻¹ at 6.4 kW kg⁻¹, demonstrating high‑capacity, high‑rate performance.

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 H2 O on Zn2+ intercalation into bilayer V2 O5 ·nH2 O is demonstrated. The results suggest that the H2 O-solvated Zn2+ possesses largely reduced effective charge and thus reduced electrostatic interactions with the V2 O5 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.