Preparation of N-doped porous carbon nanofibers derived from their phenolic-resin-based analogues for high performance supercapacitor

Carbon nanofibers (CNFs), possessing high electrical conductance and facilitating fast electron transfer due to 1D structure, attract more research interests in the field of energy storage/conversion. It is highly desirable to develop a simple synthetic approach to prepare high quality CNFs for high efficient electrode material. Herein, a facile method is developed to prepare nitrogen-doped porous CNFs with high aspect ratio by direct pyrolysis of phenolic-resin-based precursors which are synthesized via a simple hydrothermal approach. After activation by KOH, the nitrogen-doped porous CNFs demonstrate a high surface area up to 1814.1 m2/g thereby offering a high capacitance while working as the electrode material assembled in a supercapacitor. The activated CNFs as electrode material present a high specific capacitance of 333.5F g−1 at a current density of 0.5 A g−1 in a three-electrode cell. After 10,000 cycles of charge–discharge tests at 5A g−1, the decay in specific capacitance is only 3.7 %, indicating a high reversibility. Also, the tests in a two electrode system show a high energy density of 8.6 Wh kg−1 at a power density of 25 W kg−1. Therefore, the nitrogen-doped CNFs derived from its phenolic-resin-based precursor hold a promise for an efficient electrode material in supercapacitor.