Preparation of biomass composite activated carbon based supercapacitor materials and their application in energy storage devices

We prepared expired bread activated carbon (AC), ganoderma spore AC and mixed biomass AC by charring and chemical activation methods. The biomass AC based composite was obtained by simple mechanical compounding of graphene and biomass AC. The specific capacitance was 290.47F/g at a current density of 1 A/g. It retained a 99.92% specific capacitance value after 5000 cycles at a current density of 10 A/g. Assembled with hollow NiCo2S4 micron spheres into devices, the specific capacitance of the device was 148.40F/g at a current density of 1 A/g, and the energy density reached 56.11Wh/kg at a power density of 807.98 W/kg. The biomass composite AC based supercapacitor material not only shows a higher specific capacitance value than that of a commercial activated carbon by itself, it also demonstrated significant importance in improving the overall performance of the assembled supercapacitor devices.