N, S self-doped hollow-sphere porous carbon derived from puffball spores for high performance supercapacitors

A novel N, S self-doped hollow-sphere porous carbon is directly prepared from abundant biomass puffball spores via a simple carbonization and KOH activation process for the first time. The electrochemical properties and porous structure of these carbons are explored by adjusting the amount of KOH. It is found that the obtained N, S self-doped hollow-sphere porous carbon with a KOH to carbon mass ratio of 4 (NS-HPC-4) exhibits the largest specific surface area (1431 m 2 /g), a well-developed hierarchical porous structure and moderate N/S contents. As a result, the NS-HPC-4 electrode in the supercapacitor delivers a large specific capacitance of 285 F/g at 0.5 A/g in KOH electrolyte. Furthermore, the symmetric supercapacitor based on NS-HPC-4 exhibits an energy density of 10.9 Wh/kg at a power density of 400.4 W/kg in 2 M KOH aqueous electrolyte, and achieves a high energy density of 58.4 Wh/kg at a high power density of 876.0 W/kg in 1 M Et 4 NBF 4 /AN organic electrolyte. These excellent results confirm that puffball spores derived porous carbons are promising candidates to be used in high performance supercapacitors.