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.