Designing CuO@MnCo2O4 nanowire arrays electrode on copper foam and foil substrates via chemical synthesis methods for asymmetric supercapacitor

Abstract

In this study, CuO nanowires were grown on copper foam (Cufoam) and copper foil (Cufoil) substrate with a cost-effective anodization method as core, and then MnCo2O4 nanowires were grown by hydrothermal synthesis method and three-dimensional (3D) core-shell nanowire arrays (NWAs) were obtained. The synthesized CuO NWAs, which provide a high surface area, contribute to the capacitance with the faradaic redox reaction and act as a current collector for the MnCo2O4 NWAs. Therefore, the 3D electrode design can increase the redox reaction, shorten the ions diffusion pathway, and exhibit low intrinsic resistance. The areal capacitance values of Cufoil/CuO, Cufoam/CuO, and Cufoam/CuO@MnCo2O4 electrodes were obtained at a current density of 0.5 mA cm−2 as 0.21, 1.02, and 2.82 F cm−2, respectively. The Cufoam/CuO@MnCo2O4 NWAs electrode exhibits excellent cycling stability of 97.3 % retention after 5000 cycles. In addition, an asymmetric supercapacitor (ASC) device was assembled by using the Cufoam/CuO@MnCo2O4 electrode and active carbon (AC) as the positive and negative electrodes, respectively. The ASC device operates in a potential range of 0–1.5 V and an energy density of up to 7.1 × 10−2 mWh cm−2 at a power density of 1.56 mW cm−2. This work may contribute to developing low-cost materials for energy storage devices.