Growth of CuCo2O4@MnMoO4 core/shell nanosheet arrays for high energy density asymmetric supercapacitors

Abstract Three-dimensional CuCo2O4@MnMoO4 core/shell nanosheet arrays grown on nickel foam were designed and prepared through two-step hydrothermal processes followed by a low-temperature thermal treatment. The interconnected CuCo2O4 nanosheets are uniformly decorated by ultrathin MnMoO4 nanoflakes, forming highly porous hierarchical networks. The electrochemical results reveal that the binder-free CuCo2O4@MnMoO4 electrode exhibits a superb specific capacitance of 1327.5 F g−1 at 1 A g−1 and remarkable cycling stability (maintaining 92.8% of initial capacitance over 6000 cycles). The superior supercapacitive properties can be ascribed to the high mechanical stability, large surface area, high electron/ion transfer rate, and the strong synergistic contribution from CuCo2O4 and MnMoO4. Additionally, the assembled CuCo2O4@MnMoO4//graphene hybrid supercapacitor device delivers a maximum specific energy of 58.9 Wh kg−1 at a specific power of 670 W kg−1, manifesting the great potential of the CuCo2O4@MnMoO4 core/shell nanosheet arrays as advanced electrode materials for energy storage systems.