Towards high-performance cathodes: Design and energy storage mechanism of vanadium oxides-based materials for aqueous Zn-ion batteries

Aqueous rechargeable Zn-ion batteries (AZIBs) have regarded as promising secondary chemical battery system because of the excellent safety, low cost and environmental friendliness. Nonetheless, it is still a great challenge to exploit suitable cathode materials for the insertion of zinc ions. The vanadium oxides-based materials are regarded as hopeful cathode materials of AZIBs because of their various coordination numbers and oxidation states. Especially, the hydrated, monovalent (divalent)-cations co-preinserted vanadium oxides show more excellent electrochemical performance because of the enlarged interlayer space. In this review, a comprehensive overview of the energy storage mechanisms and research development of various efficient ways to improve electrochemical performance for vanadium oxides-based compounds is presented. Finally, some insights into the future developments, challenges, and prospects of vanadium oxides-based compounds for AZIBs are proposed. This review illustrates electrochemical reaction mechanism of vanadium oxides-based compounds for AZIBs, and benefits the discovery of new AZIBs cathode materials, gives a novel viewpoint to shed light on the future innovation in vanadium oxides-based cathode materials, then facilitates the fast development and large-scale applications of AZIBs. The article will provide useful guidance for future design and construction of high-performance cathode materials for AZIBs.