Reasonable design of high-capacity MnO2/MXene/CF flexible cathodes for quasi-solid-state aqueous zinc-ion batteries

Manganese-based aqueous zinc-ion batteries (AZIBs) have garnered growing interest in the area of adaptable and wearable devices because of their properties of simple manufacturing, superior safety, and ecological compatibility. Nevertheless, the actual implementation of Mn-based cathodes has faced challenges due to their inadequate conductivity and poor cycling performance. In this study, a chemical synthesis approach was employed to directly grow MnO 2 on the surface and within the interlayer spaces of MXene. Subsequently, the composite was coated onto carbon felt (CF) using the impregnation method to fabricate binder-free MnO 2 /MXene/CF cathodes for AZIBs. The excellent conductivity and structural stability of MXene effectively enhance ion/electron transport kinetics and mitigate irreversible volume changes of MnO 2 during charge and discharge processes. CF with excellent electrical conductivity and flexibility serves as an ideal current collector and substrate material for loading active materials. Moreover, its distinctive three-dimensional porous structure facilitates optimal interaction between the electrode material and the electrolyte. Consequently, the flexible quasi-solid-state AZIB, consisting of the optimized MnO 2 /MXene/CF cathode and zinc foil anode, exhibits high charge storage performance (a specific capacity of 429.1 mAh g −1 at 0.1 A g −1 and an excellent energy density of 343.2 Wh kg −1 at 79.9 W kg −1 ). Density functional theory analysis reveals that the incorporation of MXene enhances electron adsorption on MnO 2 and significantly alters the density of states of MnO 2 , thus markedly improving its conductivity. These encouraging findings suggest that manganese-based materials hold great potential for application as cathodes in flexible quasi-solid-state AZIBs.