Phenylenediamine-formaldehyde chemistry derived N-doped hollow carbon spheres for high-energy-density supercapacitors

Benefiting from the ultrahigh surface area (2044 m2/g), suitable pore size and moderate N-doping, the N-doped hollow carbon spheres (NHCSs) demonstrate a high specific capacitance of 234 F/g in ionic liquid electrolyte (EMIBF4). The NHCSs-based symmetric supercapacitor achieves an ultrahigh energy density of 114.8 Wh/kg (based on the mass of active material). [Display omitted] Porous carbon spheres represent an ideal family of electrode materials for supercapacitors because of the high surface area, ideal conductivity, negligible aggregation, and ability to achieve space efficient packing. However, the development of new synthetic methods towards porous carbon spheres still remains a great challenge. Herein, N-doped hollow carbon spheres with an ultrahigh surface area of 2044 m2/g have been designed based on the phenylenediamine-formaldehyde chemistry. When applied in symmetric supercapacitors with ionic electrolyte (EMIBF4), the obtained N-doped hollow carbon spheres demonstrate a high capacitance of 234 F/g, affording an ultrahigh energy density of 114.8 Wh/kg. Excellent cycling stability has also been achieved. The impressive capacitive performances make the phenylenediamine-formaldehyde resin derived N-doped carbon a promising candidate electrode material for supercapacitors.