Rechargeable Aqueous Zn–V₂O₅ Battery with High Energy Density and Long Cycle Life

TLDR

The study reports an aqueous Zn–V₂O₅ battery chemistry using commercial V₂O₅ cathode, Zn anode, and 3 M Zn(CF₃SO₃)₂ electrolyte. The Zn‑storage mechanism involves reversible intercalation of hydrated Zn²⁺ into the layered V₂O₅ structure, with co‑intercalated H₂O shielding electrostatic interactions and the material transforming into porous nanosheets during cycling to increase active sites. The battery delivers a reversible capacity of 470 mAh g⁻¹ at 0.2 A g⁻¹ and retains 91.1 % after 4000 cycles at 5 A g⁻¹, demonstrating high energy density, long cycle life, safety, scalable synthesis, and suitability for stationary grid storage.

Abstract

We report an aqueous Zn–V2O5 battery chemistry employing commercial V2O5 cathode, Zn anode, and 3 M Zn(CF3SO3)2 electrolyte. We elucidate the Zn-storage mechanism in the V2O5 cathode to be that hydrated Zn2+ can reversibly (de)intercalate through the layered structure. The function of the co-intercalated H2O is revealed to be shielding the electrostatic interactions between Zn2+ and the host framework, accounting for the enhanced kinetics. In addition, the pristine bulk V2O5 gradually evolves into porous nanosheets upon cycling, providing more active sites for Zn2+ storage and thus rendering an initial capacity increase. As a consequence, a reversible capacity of 470 mAh g–1 at 0.2 A g–1 and a long-term cyclability with 91.1% capacity rentention over 4000 cycles at 5 A g–1 are achieved. The combination of the good battery performance, safety, scalable materials synthesis, and facile cell assembly indicates this aqueous Zn–V2O5 system is promising for stationary grid storage applications.