Nitrogen-Enriched Porous Carbon Nanofiber Mat as Efficient Flexible Electrode Material for Supercapacitors

Freestanding nitrogen-doped porous carbon nanofiber (NCNF) mats were prepared by electrospinning polyacrylonitrile/ poly(m-aminophenol) (PAN/PmAP) precursor blends with different polymeric compositions followed by thermal stabilization and carbonization. The morphology, pore structure, and surface elemental compositions of as-prepared NCNFs were characterized by different techniques such as scanning electron microscopy, transmission electron microscopy, N-2 adsorption, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The charge-storage capability of the fabricated NCNFs was investigated in KOH electrolyte. The electrochemical performances of NCNFs were evaluated by varying the PmAP loading in the blend compositions. The highest specific capacitance of 347.5 F g(-1) at 0.5 mA cm(-2) together with a capacitance retention of 173.2 F g(-1) at 20 mA cm(-2) was achieved for the PAN:PmAP (85:15 w/w) NCNFs (NCNF85:15). The volumetric capacitance of 200.8 F cm(-3) at 0.5 mA cm(-2) was recorded for NCNF85.15. The NCNF85:15 showed the maximum energy density of 12.1 Wh kg(-1) at 0.093 kW kg(-1) and good cycling stability with 90.5% capacitance retention after 10 000 cycles. The excellent capacitive performances of the NCNF85:5 were attributed to high effective surface area, high content of mesoporosity, good conducvity, and high fraction of heteroatom-doped carbon, which result in both electrochemical double-layer and Faradaic capacitance contributions.