Improved strategies for ammonium vanadate-based zinc ion batteries

Aqueous zinc ion batteries (ZIBs) are becoming increasingly popular as a new form of resource for electrochemical energy storage due to their high safety, affordability, availability of natural zinc resources, and high gravimetric energy density. However, the development of high-performance ZIB cathode materials remains a great challenge because current ZIB cathode materials tend to have low conductivity and relatively complex energy storage mechanisms. Compared with other cathode materials, ammonium vanadate-based materials have been extensively investigated as cathode materials for ZIBs due to their plentiful availability and high potential capacity. In this review, we highlight the mechanisms and challenges of ammonium vanadate-based materials and summarize the progress in improved strategies including the design of different morphologies, doping with different impurities, the introduction of different intercalators, and combination with other materials for high-performance ZIBs. Finally, the paper also provides an outlook on the future challenges and development prospects of ammonium vanadate-based cathode materials in ZIBs.