NiCo2S4 nanosheet-modified hollow Cu-Co-O nanocomposites as asymmetric supercapacitor advanced electrodes with excellent performance

Abstract

In this study, hollow CuCo2O4/CuO nanocomposites were fabricated by a hydrothermal method for the first time. NiCo2S4 nanosheets were coated on these nanocomposites by simple potentiostatic electrodeposition to form NiCo2S4 nanosheet-modified hollow CuCo2O4/CuO nanocomposites as advanced electrodes for asymmetric supercapacitors. A unique three-dimensional (3D) nanoarchitecture was built using one-dimensional (1D) hollow CuCo2O4/CuO nanocomposites and two-dimensional (2D) NiCo2S4 nanosheets. This multidimensional synergistic effect resulted in hollow CuCo2O4/CuO@NiCo2S4 nanocomposites with high areal capacitance (10.33 F cm−2, 2459 F g−1) at 10 mA cm−2, good rate capability, and high stability (93.2% retention after 10,000 cycles). Moreover, an environmentally friendly and economical asymmetric supercapacitor was prepared by using hollow CuCo2O4/CuO@NiCo2S4 nanocomposites and activated carbon (AC) as positive and negative electrodes, respectively. This assembly displayed a high energy density of 0.824 mWh cm−2 at a power density of 8 mW cm−2, and 91.2% of the specific capacitance was preserved after 10,000 cycles at 20 mA cm−2. The novel electrode material with a coordinative nanostructure prepared herein provides new possibilities for fabricating high-performance supercapacitors.