N-doped porous carbon nanofibers derived from N-rich cross-linked polymer for high-performance supercapacitors

Porous carbon materials with regular morphological structure and high heteroatom content have great application potentials in the area of novel energy storage devices. Herein, a family of novel N-doped porous carbon nanofibers are prepared by using a facile CuCl2-mediated activation of a fiber-like N-rich cross-linked polymer, which is readily accessible based on a solvent-thermal reaction between 2,4,6-tris(4-aminophenyl)triazine and dimethyl succinyl succinate. With the assistance of the mild activating reagent (CuCl2), the as-prepared carbon nanofibers (C-X-CuCl2) retain the fibrous morphology of precursor and achieve abundant heteroatom species in the carbon skeleton. The C-X-CuCl2 samples obtain the highest specific surface area of 1964.9 m2 g-1 and the highest N/O doping contents of 10.10 and 15.06 at.%, respectively, all of which are favorable for improving electrochemical performance when applied in supercapacitors. The C-750-CuCl2 electrode delivers the best-performed overall capacitance of 281.5 F g-1 at 0.5 A g-1, and its symmetrical supercapacitors with aqueous electrolyte (6 M KOH) show 93.1% of capacity retention after 10000 charging/discharging operations at 5.0 A g-1. An outstanding energy density of 75.5 Wh kg-1 at a power density of 300 W kg-1 is realized as well for the C-750-CuCl2-based symmetrical supercapacitors when 1-ethyl-3-methylimidazolium tetrafluoroborate is used as the electrolyte. These results indicate that the C-750-CuCl2 carbon nanofiber is a promising material for high-performance supercapacitors.