Preparation of Hierarchical Micro-Meso Porous Carbon and Carbon Nanofiber from Polyacrylonitrile/Polysulfone Polymer Via One-Step Carbonization for Supercapacitor Electrodes

•The same polymer precursor of polyacrylonitrile/polysulfone is used to prepare carbon nanofiber and porous carbon.•Polysulfone can be as a sacrificial polymer to prepare carbon nanofiber with a large specific surface area.•Both carbon nanofiber and porous carbon electrodes show excellent electrochemical performances.•The carbon nanofiber electrode has a higher specific capacitance of ∼ 360 f g−1 than the PC electrode ∼ 290 f g−1 at 10 mV s−1.