One-step synthesis of nitrogen−fluorine dual-doped porous carbon for supercapacitors

The development of doped porous carbon materials has attracted much attention in the application of supercapacitors. This study reports a straightforward one-step method to prepare nitrogen−fluorine dual-doped porous carbon through direct carbonization of commercially available 2-methylimidazole and tetrafluoroterephthalonitrile in the presence of KOH. The obtained porous carbon demonstrated superb specific surface area of more than 2,000 m2 g−1 and high fluorine and nitrogen doping (> 10% in total). The obtained materials were investigated for fabrications of supercapacitive electrodes and devices. The doped carbon registered a specific capacitance of 354.4 F g−1 at 0.5 A g−1, with a capacitance retention of 72% at 10 A g−1 using H2SO4 electrolyte in a three-electrode system. In the cyclic stability test, little capacitance and Coulombic decays were observed after 5,000 cycles at 10 A g−1. An assembled symmetric supercapacitor with a voltage window of 0–1.2 V yielded a specific energy of 7.7 Wh kg−1 at 150 W kg−1 in Na2SO4 electrolyte. This work presents a new protocol for the synthesis of high-performance carbon-based materials for energy-storage applications.