Rapid Electrochemical Activation of V₂O₃@C Cathode for High‐Performance Zinc‐Ion Batteries in Water‐in‐Salt Electrolyte

Abstract

Aqueous Zn-ion batteries (ZIBs), with the advantages of low cost, high safety, and high capacity, have great potential for application in grid energy storage and wearable flexible devices. However, their commercial application is still restricted by their inferior long-term cycling stability, Zn dendrite formation, and the decomposition of aqueous electrolyte. In this study, a Zn|Zn(CF₃ SO₃ )₂ +LiTFSI|V₂ O₃ @C cell is constructed to address the above issues. The V₂ O₃ @C electrode can be fully oxidized into amorphous V₂ O₅ @C simultaneously with Zn²⁺ and H₂ O co-insertion. The cell delivers a high specific capacity of more than 240 mAh g^-1 at 3 A g^-1 , with extraordinary coulombic efficiency and capacity retention. The excellent electrochemical performances are attributed to synergistic effects between the V₂ O₃ @C electrode and the water-in-salt electrolyte with enhanced stability and improved interface reaction kinetics. Systematic improvements of this architecture indicate much promise for application.