Storage mechanisms and improved strategies for manganese-based aqueous zinc-ion batteries

Aqueous Zn-ion rechargeable batteries have been regarded as a promising large-scale energy storage system due to their abundant resources, high security, environmental friendliness and acceptable energy density. Various manganese-based compounds with low cost and high theoretical capacity are widely used in aqueous Zn-ion batteries (AZIBs). In addition, AZIBs using manganese-based cathode materials have different energy storage mechanism. In this review, four different zinc ion storage mechanisms of AZIBs with manganese-based cathode materials are analyzed in detail on the basis of previous studies, and various strategies for improving the electrochemical performance of manganese-based positive electrode materials are analyzed, including structural design, synthesis of manganese-based composites, intercalation, defect engineering, interfacial modification and electrolyte optimization. Finally, we discuss the limitations that need to be overcome and perspectives on AZIBs are summarized to provide potential future research directions.