Copper chloride (CuCl2)-doped polypyrrole (PPy)/multiwalled carbon nanotube (MWCNTs) nanocomposites were synthesized by an insitu oxidative polymerization method with ammonium persulfate as the oxidant in HCl medium and investigated as electrode materials for supercapacitors. The interaction of metal cations (Cu2+ ions) with PPy was confirmed by Fourier transform infrared spectroscopic analysis. The morphology of the nanocomposites was characterized by field emission scanning electron microscopy and high-resolution transmission electron microscopy. Electrochemical characterizations of the composites materials were carried out by a three-electrode probe method, where platinum and a saturated standard calomel electrode were used as the counter and reference electrodes, respectively. A 1M KCl solution was used as the electrolyte for all of the electrochemical characterizations. The transition-metal-ion doping enhanced the electrochemical properties of the conducting polymer. Among all of the composites, the CuCl2-doped PPy/MWCNTs showed the highest specific capacitance value of 312 F/g at a 10 mV/s scan rate. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013