Synthesis and performances of a ZnCo₂O₄@MnMoO₄ composite for a hybrid supercapacitor

To overcome the disadvantages of poor intrinsic conductivity and stability of ZnCo₂O₄, a ZnCo₂O₄@MnMoO₄ composite as an emerging pseudocapacitor electrode material with high specific capacitance, environmental friendliness, morphological diversity, and unique hierarchical structure was synthesized via a simple two-step hydrothermal method. The research results indicate that the ZnCo₂O₄@MnMoO₄ composite can present a high specific capacity of 1628 F g^-1 at a current density of 1 A g^-1 and good cycling stability with 69% capacity retention after 10 000 cycles at 10 A g^-1. Hybrid supercapacitors (HSCs) assembled with the ZnCo₂O₄@MnMoO₄ cathode and activated carbon anode can deliver an energy density of 48 W h kg^-1 at a power density of 695 W kg^-1, and their capacity retention reached 61% after 8000 charge-discharge cycles at a current density of 10 A g^-1. This could be attributed to the synergistic effect of the specific surface area and electrical conductivity enhanced by compositing ZnCo₂O₄ with MnMoO₄. As a result, the excellent electrochemical properties show that the ZnCo₂O₄@MnMoO₄ composite has strong application potential for high-performance supercapacitors.