Layered MnO2@PDA as cathode material toward high-performance aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) can benefit from a deep understanding of the electrochemical reaction mechanism of cathode materials, which can assist in resolving issues such as cathode dissolution and electrostatic interactions. We reported a straightforward two-step synthesis of polydopamine coated MnO 2 (MnO 2 @PDA) and revealed the energy storage mechanisms in AZIBs. The layered structure of MnO 2 creates a generous passage for the insertion of H + /Zn 2+ ions. Simultaneously, the plethora of functional groups within PDA exerts a robust desolvation effect, bolstering the transfer rate of H + /Zn 2+ . This effect significantly enhances the overall efficiency and performance of cathode. The AZIBs, incorporating MnO 2 @PDA cathode material, consequently exhibit a satisfactory cycling capacity (412 mAh g −1 at 0.1 A g −1 ) and a superb specific energy (561.6 Wh kg −1 at 136.34 W kg −1 ). This work provides a new path for design strategies and catalytic mechanisms of MnO 2 @PDA cathode.