V2O5-based cathodes for aqueous zinc ion batteries: Mechanisms, preparations, modifications, and electrochemistry

Aqueous zinc ion batteries (ZIBs) are considered one of the extremely promising energy storage devices due to their high safety, low cost, and environmental friendliness. In the past five years, V2O5, the most common and stable layered vanadium oxide, has been widely investigated as a cathode material in aqueous ZIBs for its high theoretical capacity and the possibility of multi-electron redox. However, Zn/V2O5 batteries still suffer from considerable challenges in achieving long-cycle capacity and high energy density. Nowadays, various modification strategies are employed to enhance the electrochemical performance and other key performance parameters of V2O5 cathodes. In this review, we systematically discuss the structure, energy storage mechanisms, and preparation methods of V2O5. In addition, modification strategies such as ion/molecule pre-intercalation, composite with other materials, defect engineering, and morphological structure design as well as their recent research progress are highlighted. Finally, the challenges faced by high-performance V2O5-based cathodes and promising research directions are pointed out, aiming at the realization of mature applications with Zn/V2O5 batteries.