Nanostructured SnO2 was prepared by the sol-gel method. Aniline monomer was polymerized in the suspension of nanocrystalline SnO2 to form inorganic-organic composite materials, in which SnO2 nanoparticles were embedded within netlike polyaniline (PANI). Structural and morphological characterizations of SnO2 and PANI/SnO2 were carried out using power X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Their electrochemical properties were also investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The as-prepared composites had excellent properties in the capacitance, and its specific capacitance was up to 305.3 F g(-1) with a specific energy density of 42.4 Wh kg(-1) and a coulombic efficiency of 96%. The results indicated that the PANI/SnO2 had a synergistic effect of the complementary properties of both components. (C) 2009 Published by Elsevier B.V.