Ultra-high nitrogen content biomass carbon supercapacitors and nitrogen forms analysis

Doping of heteroatoms is an effective way to improve the specific capacitance of carbon-based supercapacitors. In this paper, we prepared an active biomass carbon electrode with a considerable nitrogen content of 10.82%. In the N-doped biomass carbon materials, pyridine nitrogen and pyrrole nitrogen were the main forms of nitrogen, and the presence of sp3 hybrid nitrogen greatly enhanced the specific capacitance. Among the precursors of biomass in this study, fungal hypha (FH) enabled the best electrochemical performance of carbon electrode with specific capacitances of up to 279 F/g and 190 F/g at a high current density of 1 A/g and 20 A/g, respectively. In addition, the sample possessed an excellent anti-radiation capability, with the specific capacity of 227 F/g at 1 A/g after irradiated by γ-ray (50 kGy). This universal and cost-friendly method will expand the specific surface area of biomass materials and augment the amount of nitrogen in biomass carbon materials.