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.