Nitrogen-doped graphitic hierarchically porous carbon nanofibers obtained via bimetallic-coordination organic framework modification and their application in supercapacitors

Abstract

Herein, N-doped graphitic hierarchically porous carbon nanofibers (NGHPCF) were prepared by electrospinning the composite of bimetallic-coordination metal–organic frameworks and polyacrylonitrile, followed by a pyrolysis and acid wash process. Control over the N content, specific surface area, and degree of graphitization of NGHPCF materials has been realized by adjusting the Co/Zn metal coordination content as well as the pyrolysis temperature. The obtained NGHPCF with a high specific surface area (623 m² g⁻¹) and nitrogen content (13.83 wt%) exhibit a high capacitance of 326 F g⁻¹ at 0.5 A g⁻¹. In addition, the capacitance of 170 F g⁻¹ is still maintained at a high current density (40 A g⁻¹); this indicates a high capacitance retention capability. Furthermore, a superb energy density (9.61 W h kg⁻¹) is obtained with a high power density (62.4 W kg⁻¹) using an organic electrolyte. These results fully illustrate that the prepared NGHPCF binder-free electrodes are promising candidates for high-performance supercapacitors.