N‐Doped Porous Carbon Nanofiber Mats for High‐Performance Flexible Supercapacitor Electrodes

Carbon materials are widely utilized as a versatile material for supercapacitors in energy storage for their extraordinary electrical conductivity, chemical stability, and cost‐effectiveness. But achieving commercial viability still poses a significant challenge in improving the capacitance and energy density. To meet the requirements, an N‐doped carbon nanofiber mat (porous carbon nanofiber (PCNF)) is prepared for free‐standing electrodes with polyacrylonitrile and polyvinylpyrrolidone (PVP) electrostatically spun nanofibers as precursors. PVP is a pore‐forming agent that decomposes on the carbon nanofibers during calcination to form pores, and the unique porous structure results in a remarkable performance of supercapacitor. The result shows that the PCNF30 exhibits high flexibility and electrochemical properties with a specific capacitance of 255.6 F g −1 at 2 A g −1 about 2.5 times higher than PCNF0 (105.3 F g −1 at 2 A g −1 ) and satisfactory rate performance with only about 39.8% specific capacitance loss at 100 A g −1 . In addition, the symmetrical supercapacitor of PCNF30//PCNF30 has high energy density, up to 8.85 Wh kg −1 at 1.25 kW kg −1 , and a 90.8% retention rate after undergoing 10 000 cycles. Those results suggest an efficient approach for PCNFs‐based materials in flexible electronic devices.