Heteroatoms-doped hierarchical porous carbon with multi-scale structure derived from petroleum asphalt for high-performance supercapacitors

Rational pore structure and surface properties of carbon materials are significant for their practical application in supercapacitors (SCs). Pursuing a simple and costless synthesis approach is of great importance, yet full of challenges. Herein, heteroatoms-doped hierarchical porous carbon (h-PC) with nanosheets/hollow nanospheres multi-scale structure is fabricated via a facile dual templates strategy with using petroleum asphalt as carbon precursor. The multi-scale pores are controlled by changing the ratio of target templates. Benefitting from high conductivity, plentiful ion-available surfaces, hierarchical porosity with suitable micro-mesoporous channels, and N, O, S heteroatoms, the resultant h-PC electrodes exhibit high specific capacitance of 437 F g−1 at 1 A g−1, and superior rate capability of 336 F g−1 at 50 A g−1 in three-electrode system with KOH electrolyte. The assembled symmetric SCs manifest the maximum energy density of 12.95 Wh kg−1 at 250 W kg−1 and robust cycling stability. Impressively, the energy density is further enhanced to 25.5 Wh kg−1 at 450 W kg−1 with using Na2SO4 electrolyte. Even in all-solid-state symmetric SCs, it still demonstrates an encouraging property. This work may provide new insights for designing advanced carbon-based materials for capacitive energy storage.