Progress of vanadium-based oxides as cathode materials for aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) present the advantages of high theoretical capacity, good safety and environmental friendliness, also with desirable application prospects in the field of energy storage. Here, vanadium-based cathode materials have attracted wide attention due to their high theoretical specific capacity and various structures. This work offers a comprehensive review of the status and research progress of vanadium-based oxides as cathode materials for AZIBs. At first, we describe the evolution of zinc-ion batteries (ZIBs) and the strengths of AZIBs. Subsequently, we elaborate the classification and Zn storage mechanisms of AZIBs cathode materials, including the mechanisms of Zn²⁺ intercalation/deintercalation, Zn²⁺/H⁺ co-insertion, chemical conversion reactions and dissolution/deposition mechanism. Among them, vanadium-based oxides mainly store energy through the first three mechanisms. Then, this review focuses on the structural characteristics of vanadium-based oxides, and introduces the research progress of vanadium-based monometallic oxides, vanadium-based bimetallic oxides, vanadium-based polymetallic oxides and other types, along with their electrochemical performances summarization. In addition, we discuss the improvement design approaches of vanadium-based oxides, such as morphology optimization, lattice optimization, heterostructure construction and so on. Finally, the shortcomings of vanadium-based oxides in current study of AZIBs cathode materials are summarized, also with their future research prospects.