The self-assembled nanofibers for supercapacitor material have been fabricated by electrospinning process. The characterizations of the nanofibers were investigated by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that P123 effectively inhibits grain growth of Co3O4, and plays a critical role in the formation of self-assemble nanofibers. Electrochemical properties were characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. (C) 2013 The Electrochemical Society. All rights reserved.