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

Abstract

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.