A nitrogen-doped 3D open-structured graphite nanofiber matrix for high-performance supercapacitors

Abstract

An N-doped 3D ordered mesoporous graphite nanofiber (3D OMGNF-N) with an N-doping level of up to 16.5 at% for high-performance supercapacitors is designed and synthesized. OMGNF-N shows a conductive 3D open-structured matrix, large surface area, hierarchical porous structure, and great number of electrochemically active sites by N-doping. The supercapacitors (SCs) based on OMGNF-N show a remarkably excellent electrochemical behavior with a high specific capacitance of 460, 420, and 345 F g⁻¹, respectively, in KOH, H₂SO₄, and KCl electrolytes when measured in a three-electrode configuration. In practical devices, the material can achieve a remarkably high capacitance of 426 F g⁻¹, good cycling stability with 92% capacitance retention after 50 000 cycles. Moreover, the OMGNF-N based SCs show a remarkably excellent electrochemical behavior with good rate capability and low internal resistance, thereby leading to both high power density and relatively high energy density.