Polytetrafluoroethylene-assisted N/F co-doped hierarchically porous carbon as a high performance electrode for supercapacitors

Abstract

In this study, we propose a novel template and chemical activation method to fabricate the nitrogen and fluorine co-doped hierarchically porous carbon with polytetrafluoroethylene-polyaniline as the precursor and KOH as the activation reagent. The key to this strategy is the utilization of polytetrafluoroethylene as an additive during the process, which not only serves as a fluorine source but also acts as a template to increase the specific surface area. Moreover, polytetrafluoroethylene disappears after carbonization without requiring a complicated template-removal process. The as-prepared materials possess a favorable hierarchical porous structure that is conductive to the transportation and diffusion of ions. They also acquire effective nitrogen and fluorine co-doping to further improve the electrochemical performance. The optimized carbon material displays a high specific capacitance (291 F g−1 at 0.5 A g−1) and maintains 180 F g−1 even at 100 A g−1 in 6 M KOH. Moreover, it presents an excellent cycling performance with 95.5% capacitance retention after 10,000 cycles. The fabricated symmetric supercapacitor delivers high energy densities of 12.91 Wh kg−1. These results represent a new performance record for nitrogen and fluorine co-doped porous carbon-based supercapacitors, rendering the polytetrafluoroethylene particles to be a promising template for producing porous carbon materials.