Fabrication of ultrahigh supercapacitor device based on ZnCo2O4@MnO2 with porous nanospheres decorated on flower-shaped structure

Abstract

Being a fundamental component of energy storage devices, high-performance supercapacitors are always of utmost significance. In addition to long-term cycle durability, these supercapacitors should have higher power and energy densities. So, here we report an innovative approach for designing the hierarchical flower-like structures of binary metal oxides decorated with porous nanospheres of manganese oxide. The synergistic coupling of ZnCo2O4 and MnO2 offers a twofold charging capacity, while the porous framework provides good accessibility to the ions of electrolytes for storage inside the material. Furthermore, the Asymmetric device (ASD) is fabricated to achieve high energy density by employing ZnCo2O4@MnO2 as an anode material and activated carbon as a cathode material. The fabricated device exhibits an ultrahigh energy density of 247 Wh/kg at 1250 W/kg power density and good cycle stability after 5000 charge-discharge cycles with 97.2 % retention. Moreover, an array of 51 LEDs is lightened for nearly 16 min by connecting six asymmetrical devices in series to each other. As an astonishing result of the fabricated electrochemical asymmetric supercapacitive device, it holds great promise for industrial energy storage solutions.