As an energy storage device, supercapacitors are practically used in many fields due to their high power density and long service life. Among the components of supercapacitors, electrode materials play a key role in the performance of the device, it is thus of great significance to prepare electrode materials with superior electrochemical performance. NiCo2S4 was prepared by a hydrothermal method using nickel acetate and cobalt acetate as raw materials, glutathione as a morphology control agent and a sulfur source. The effect of hydrothermal reaction time on the microstructure, morphology and electrochemical performance of NiCo2S4 was investigated. The results show that the NiCo2S4 material prepared under the action of glutathione has a yolk?shell structure. The specific capacitance is 1 552.7 F/g when the current density is 0.5 A/g, and the specific capacitance can be maintained at 61.3% at 10 A/g. After 2 000 cycles, the specific capacitance retention of the material can be maintained at 79.3%. A supercapacitor can be assembled with NiCo2S4 and activated carbon as positive and negative electrodes, respectively. This hybrid supercapacitor can provide 33.9 W·h/kg energy density when the power density is 800 W/kg. After 2 000 charge and discharge cycles, the specific capacitance retention rate is 89%.