Nitrogen-doped hollow activated carbon nanofibers as high performance supercapacitor electrodes

• Novel continuous hollow carbon nanofibers with randomly distributed open swells.
• NH3 activation leads to high content of N-doping and superior areal capacitance.
• The HACNFs can be directly used as the electrodes for supercapacitor.
• The HACNFs electrode shows excellent rate capability and cycling stability.

Nitrogen-doped hollow activated carbon nanofibers (HACNFs) have been prepared by the concentric electrospinning and the following NH3 activation. The as-obtained samples were directly used as supercapacitor electrode without binders and conductive additives. Owing to the unique hollow architecture and high N-doping level (8.2%), the HACNFs exhibit a high specific capacitance of 197 F g−1 at 0.2 A g−1, which is 1.33 times than that of the solid electrospun nanofibers activated in the same condition. The samples also possess a superior rate capability of 72.1% (143 F g−1) at 20 A g−1 and long-term cycling stability with a retention of 98.6% after 1000 cycles at 5 A g−1 in 6 M KOH.