Preparation of rGO/Ni2ZnS4 and high-performance asymmetric supercapacitors with GO/ZIF-8 template

Graphene oxide (GO) was used as a substrate, and ZIF-8 was grown in situ on the GO surface and used as a template. The rGO/Ni2ZnS4 composite was prepared by nickel nitrate etching, carbonization, and hydrothermal vulcanization. X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and morphology of the composite material. Then the rGO/ Ni2ZnS4 composite material was made into a cathode material, and its electrochemical performance was tested. The test results showed that the specific capacitance value of the rGO/Ni2ZnS4-1.5h electrode material was as high as 1150 F center dot g 1 at a current density of 1 A center dot g 1, when the current density reaches 10 A center dot g 1, the rate performance is 63.3%. After 2000 cycles at a current density of 10 A center dot g 1, the capacitance retention rate is 59.7%. In addition, an asymmetric capacitor composed of AC//rGO/Ni2ZnS4-1.5h has an energy density of 31.06 Wh center dot kg 1, when the power density is 750.44 W center dot kg 1. When the high power density is 7489.18 W center dot kg 1, the energy density remains at 12.69 Wh center dot kg 1.