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. [ABSTRACT FROM AUTHOR]