Zn/V₂O₅ Aqueous Hybrid-Ion Battery with High Voltage Platform and Long Cycle Life

TLDR

Aqueous zinc‑ion batteries attract increasing attention due to their low cost, high safety, and potential for stationary energy storage, yet achieving both high cycling stability and high energy density remains a major challenge. The study aims to develop a novel Zn/V₂O₅ rechargeable aqueous hybrid‑ion battery system using porous V₂O₅ as cathode and metallic zinc as anode. The system employs porous V₂O₅ as cathode, metallic zinc as anode, and a water‑in‑salt electrolyte to raise the discharge platform. The V₂O₅ cathode delivers 238 mAh g⁻¹ at 50 mA g⁻¹, retains 80 % of capacity after 2000 cycles at 2000 mA g⁻¹, and the water‑in‑salt electrolyte increases the discharge platform from 0.6 to 1.0 V, demonstrating simultaneous enhancement of energy density and cycling stability.

Abstract

Aqueous zinc-ion batteries attract increasing attention due to their low cost, high safety, and potential application in stationary energy storage. However, the simultaneous realization of high cycling stability and high energy density remains a major challenge. To tackle the above-mentioned challenge, we develop a novel Zn/V2O5 rechargeable aqueous hybrid-ion battery system by using porous V2O5 as the cathode and metallic zinc as the anode. The V2O5 cathode delivers a high discharge capacity of 238 mAh g-1 at 50 mA g-1. 80% of the initial discharge capacity can be retained after 2000 cycles at a high current density of 2000 mA g-1. Meanwhile, the application of a "water-in-salt" electrolyte results in the increase of discharge platform from 0.6 to 1.0 V. This work provides an effective strategy to simultaneously enhance the energy density and cycling stability of aqueous zinc ion-based batteries.