Preparation of hierarchical micro-meso porous carbon and carbon nanofiber from polyacrylonitrile/polysulfone polymer via one-step carbonization for supercapacitor electrodes

Currently, the supercapacitor attracts much attention because of its long cycling life, fast charge-discharge, high power density, and excellent security. Carbon-based active materials have already become promising electrode materials for supercapacitors, which determine the performance of supercapacitors. Compared to other carbon based active materials, carbon nanofiber (CNF) and porous carbon (PC) have many advantages of low cost, easy manufacture, good conductivity, and stability. However, it is still a challenge to prepare CNF and PC electrodes used for supercapacitors with excellent physical-chemical properties through simple strategies. Herein, we innovatively use the same precursor, i. e. polyacrylonitrile/polysulfone blend polymer to prepare CNF and PC through one-step carbonization. The morphologies, chemical elements, graphitization extents, and porosity textures of as-prepared carbon materials are analyzed by Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD)/Raman, and N2 physisorption, respectively. Both CNF and PC have large specific surface areas, hierarchical micro-meso pores, and perfect graphitization extents, which show excellent electrochemical performances when they are used as electrodes in supercapacitors. By contrast, the CNF electrode has a higher specific capacitance of 360 F g-1 than the PC electrode 290 F g-1 at 10 mV s-1. The difference in results may stem from the larger surface area, interconnected fiber-fiber structure, and nanoscale structure within CNF.