NiCo 2 S 4 nanosheet arrays have been successfully grown on carbon cloth via an easy hydrothermal way, which were then used to assemble asymmetric supercapacitors. The microstructures, the crystal structures and the electrochemical properties were carefully studied, and the NiCo 2 S 4 nanosheet arrays exhibited impressive specific capacitance (SC) of 184.2 mAh/g at 1 A/g. The asymmetric supercapacitors (ASCs) with NiCo 2 S 4 nanosheets as positive electrode demonstrated the energy density of 55.6 Wh/kg at 1.6 kW/kg. Furthermore, good cycle stability (93.72% after 5000 cycles) can be also possessed.