Macroscopic synthesis of ultrafine N–doped carbon nanofibers for superior capacitive energy storage

Carbon nanofibers (CNFs) with excellent electric conductivity and high surface area have attracted immense research interests in supercapacitors. However, the macroscopic production of CNFs still remains a great challenge. Herein, ultrafine N–doped CNFs (N–CNFs) with a diameter of ∼20 nm are synthesized through a simple and scalable sol-gel method based on the self-assembly of phenolic resin and cetyltrimethylammonium bromide. When employed in aqueous supercapacitors, the obtained activated N–CNFs manifest a high gravimetric/areal capacitance (380 F g⁻¹/1.7 F cm⁻²) as well as outstanding rate capability and cycling stability. Besides, the activated N–CNFs also demonstrate excellent capacitive performance (330 F g⁻¹) in flexible quasi-solid-state supercapacitors. The remarkable electrochemical performance as well as the easy and scalable synthesis makes the N–CNFs a highly promising electrode material for supercapacitors.