Electroactivation-induced hydrated zinc vanadate as cathode for high-performance aqueous zinc-ion batteries

Highlights: • Hydrated zinc vanadate was formed from V₂O₅ via an initial activated phase transformation process induced by H₂O. • Hydrated zinc vanadate combines two modification strategies of special morphology and crystal structure adjustment. • Hydrated zinc vanadate exhibited considerable exhibited enhanced cycle performance and improved reaction kinetics. • Activated phase transformation was demonstrated to be an effective method to improve the electrochemical performance. -- Abstract: Aqueous zinc-ion batteries have great potential applications in the field of energy storage; however, their development is limited by the low availability of high-performance cathode materials. In this study, the phase transformation of Yolk-shell V₂O₅ (YS-V₂O₅) to hydrated zinc vanadate (Zn_0.34V₂O₅• 0.37H₂O; HZVO) was driven by water molecules via electrochemical activation. The resulting HZVO was used as the host material for the insertion/extraction of zinc ions. The HZVO material exhibited a specific capacity of 85.2% (113.3 mAh g⁻¹) after 1000 cycles at a current density of 8.0 A g⁻¹. Moreover, the diffusion coefficient of zinc ions was larger than that of conventional cathode materials, ranging from 10⁻⁹ to 10⁻⁸ cm² s⁻¹. We believe that our approach can contribute to the development of advanced cathode materials for application in zinc-ion batteries.