Simultaneous cross-linking and pore-forming electrospun carbon nanofibers towards high capacitive performance

Abstract

Large effective surface area and high electrical conductivity are critical for the high-performance carbon-based electrode materials for supercapacitors. Herein, three-dimensional (3D) cross-linked nitrogen-enriched porous carbon nanofibers (C-CNFs) are facilely prepared by electrospinning of polyacrylonitrile/zinc chloride (PAN/ZnCl2) precursor, preoxidation and carbonization of the electrospun composite nanofibers. The ZnCl2 additive makes effects of both cross-linking and pore-forming electrospun carbon nanofibers simultaneously. The as-prepared C-CNFs exhibits a good rate capability of about 60% with current densities ranging from 1 to 60 A g−1, excellent cycling stability of 97.3% over 60,000 cycles in alkaline electrolyte, and high specific capacitance of 214 F g−1 at 1.0 A g−1 in acidic electrolyte, all of which are significantly superior to the non-cross-linked carbon nanofibers. The significant enhancement of capacitive performance of C-CNFs can be attributed the synergistic effect of its enlarged specific surface area for more charge accumulation and cross-linked architecture that enable the electrons to fast transfer throughout the fibrous membrane. Moreover, the 3D cross-linked carbon nanofiber networks is expected to be a building block of composite electrodes fabrication for the promising applications in other systems that involve a continuous pathway for electron transport, such as the metal ion batteries and catalysis.