Hierarchical MoS2 nanowires/NiCo2O4 nanosheets supported on Ni foam for high-performance asymmetric supercapacitors

The hierarchical MoS2 nanowires/NiCo2O4 nanosheets (MS/NCO) supercapacitor electrode materials supported on Ni foam were synthesized by a two-step hydrothermal method. The capacitance was investigated by using various electrochemical methods including cyclic voltammetry, constant-current galvanostatic charge/discharge curves and electrochemical impedance spectroscopy. The MS/NCO networks show 7 times more capacitance (7.1 F cm−2) than pure NiCo2O4 nanosheets by CV at a scan rate of 2 mV s−1. The specific capacitance of the assembled MS/NCO//active carbon (AC) asymmetric supercapacitor could reach up to 51.7 F g−1 at a current density of 1.5 A g−1. Also, the maximum energy density of 18.4 W h kg−1 at a power density of 1200.2 W kg−1 was achieved, with 98.2% specific capacitance retention after 8000 cycles. These exciting results exhibit potential application in developing energy storage devices with high energy density and high power density.