Supercapacitance of nitrogen-sulfur-oxygen co-doped 3D hierarchical porous carbon in aqueous and organic electrolyte

This work report the synthesis of porous carbon with hierarchical pore structure and uniform nitrogen-sulfur-oxygen doping. The favorable pore structure (micro-, meso-, and macro-pores) is beneficial to ion adsorption and transportation, and the doping heteroatoms can introduce electrochemical active sites which contribute to additional pseudocapacitance. Therefore, the carbon material shows good electrochemical performance when employed as supercapacitor electrode. High specific capacitance (367 F g−1 at 0.3 A g−1), good rate performance and stable cycling characteristics are obtained in 6 M KOH. In addition, when tested in 1 M H2SO4, a higher specific capacitance (382 F g−1 at 0.3 A g−1) is delivered. Furthermore, the assembled symmetric cell yields a maximum specific energy of 35.3 W h kg−1 in 1 M TEABF4/AN, significantly improving the specific energy of carbon-based supercapacitors.