Nitrogen/sulfur co-doping assisted chemical activation for synthesis of hierarchical porous carbon as an efficient electrode material for supercapacitors

Abstract

The microstructure of carbon materials in terms of its specific surface area and pore structure by its activation, are the key issues which determine the electrochemical performance of supercapacitors. In this work, we developed a particular chemical activation process assisted by nitrogen/sulfur co-doping for the preparation of hierarchical porous carbon materials with high specific surface area, aiming at improving the energy density of supercapacitors. The as-obtained hierarchical porous carbon materials exhibited both high Brunauer-Emmett-Teller surface area of up to 3652m2g−1 for more ions adsorption and high porosity (2.61cm3g−1) for rapid ion transport. Attributed to the synergistic effects of these two features, the porous carbon displays high gravimetric specific capacitance (324Fg−1) in KOH aqueous electrolyte with outstanding rate performance (73.3% capacitance retention at 100Ag−1). The symmetrical supercapacitor based on our hierarchical porous carbon displays a maximum specific energy of 9.76Whkg−1 and 94.5% retention over 10000 cycles at 15Ag−1. This synthesis strategy is facile, low-cost and industrialized, which provide a promising route to prepare the hierarchical porous carbon materials for energy storage and renewable delivery devices.