A simple and scalable method is reported for fabricating a porosity-controlled carbon nanofibers with a skin-core texture by electrospinning a selected blend of polymer solutions. Simple thermal treatment of the electrospun nanofibers from solution blends of various compositions creates suitable ultramicropores on the surface of carbon nanofibers that can accommodate many ions, removing the need for an activation step. The intrinsic properties of the electrode (e.g., nanometre-size diameter, high specific surface area, narrow pore size distribution, tuneable porosity, shallow pore depth, and good ionic accessibility) enable construction of supercapacitors with large specific capacitance (130.7 Fg(-1)), high power (100 kW kg(-1)), and energy density (15.0 Wh kg(-1)). (C) 2011 Elsevier B.V. All rights reserved.