Improved electrochemical performance of ZnMn2O4/CuO composite as cathode materials for aqueous zinc-ion batteries

Spinel manganese-based oxide, as a promising cathode material for aqueous zinc-ion batteries (ZIBs), has attracted wide attention due to advantages of high voltage platform, and non-toxic and environmental friendliness. However, the poor conductivity and structural collapse due to the dissolution of Mn2+ limit the properties of the material. In this paper, the ZnMn2O4 nanoparticles with coating of Cu0-doped CuO (ZnMn2O4/CuO) were prepared by hydrothermal reaction and subsequent sintering process. The coating of Cu0-doped CuO displays a synergistic effect of two-phase composite, which effectively improves the conductivity and the charging/discharging electrochemical performance of the composite. As cathode materials for ZIBs, the ZnMn2O4/CuO composite shows a discharge-specific capacity of 150 mAh g−1 after an activation process at 300 mA g−1, it exhibits improved electrochemical performance than the pure ZnMn2O4. At a high current density of 2 A g−1, the composite displays a capacity of 118 mA h g−1, and the Coulomb efficiency of above 96% can be maintained throughout the cycles, indicating the high reversibility of charging and discharging.