Highly porous carbon nanofibers co-doped with fluorine and nitrogen for outstanding supercapacitor performance

One-dimensional (1D) carbon materials are typically used for electric double layer capacitor (EDLC) electrodes due to their excellent charge carrier mobility. However, improvement of the low capacitance and energy density of these carbon-based EDLCs has been required although they have a fast charge/discharge rate and long cycle life. In this work, nitrogen and fluorine doped mesoporous carbon nanofibers (NFMCNFs) were fabricated using a hydrothermal treatment for structural modification to create porosity and a vacuum plasma process for introducing heteroatoms into the carbon lattice. Applied to supercapacitor devices, the NFMCNFs exhibited a remarkable EDLC performance of 252.6 F g−1 at 0.5 A g−1 in a 1 M H2SO4 electrolyte. Additionally, all-solid-state flexible symmetric supercapacitors (SSCs) were assembled with a high specific capacitance of 58.1 F g−1 at 0.5 A g−1 and outstanding long-term cycle stability over 20 000 cycles. Remarkably, the SSCs also exhibited high energy and power densities of 8.07 W h kg−1 and 248 W kg−1, respectively. This dynamic porous structure and heteroatom co-doping based carbon material provides a sensational approach for designing energy storage systems.