Core-shell structured PANI-Co3O4 nanocomposites for supercapacitor applications were synthesized by combination of carbon-assisted method and in situ polymerization method. The crystalline structure, optical band gap, morphology, and hydrophilic property, as the major factors affecting the performances of supercapacitors, were investigated by X-ray diffraction (XRD), UV-vis spectrophotometry (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and water contact angle (WCA). The core-shell structured PANI-Co3O4 nanocompo sites are characterized by amorphous PANI, small bandgaps, large surface area and favorable hydrophilicity, which indicates the superior electrochemical performances of the nanocomposites as electrode material for supercapacitors. Cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) measurements were conducted in 6 M KOH aqueous solution to evaluate the electrochemical performances. The results shows that core-shell structured PANI-Co3O4 nanocomposites exhibit a high specific capacitance of 1184 F g(-1) at 1.25 A g(-1), excellent cycling stability of a capacitance retention of 84.9% after 1000 galvanostatic charge/discharge cycles, good electrical conductivity and ion diffusion behavior. (C) 2015 Elsevier B.V. All rights reserved.