Challenges and perspectives for manganese-based oxides for advanced aqueous zinc-ion batteries

Li-ion batteries (LIBs) with excellent cycling stability and high-energy densities have already occupied the commercial rechargeable battery market. Unfortunately, the high cost and intrinsic insecurity induced by organic electrolyte severely hinder their applications in large-scale energy storage. In contrast, aqueous Zn-ion batteries (ZIBs) are being developed as an ideal candidate because of their cheapness and high security. Benefiting from high operating voltage and acceptable specific capacity, recently, manganese-based oxides with different various crystal structures have been extensively studied as cathode materials for aqueous ZIBs. This review presents research progress of manganese-based cathodes in aqueous ZIBs, including various manganese-based oxides and their zinc storage mechanisms. In addition, we also discuss some optimization strategies that aim at improving the electrochemical performance of manganese-based cathodes, and the design of flexible aqueous ZIBs based on manganese-based cathodes (MZIBs). Finally, this review summarizes some valuable research directions, which will promote the further development of aqueous MZIBs. image