Multi-wall carbon nanotubes (CNTs) were coated with protonated polyaniline (PAni) in situ during the chemical polymerization of aniline. Uniform coating of CNT with PAni was observed by scanning electronic microscopy. An improvement in the covering of CNT composites was found by the association of poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT). The conductivity of composites has been compared with the conductivity of the PAni and CNT. A maximum conductivity of 96.8 S cm(-1) has been found for a PAni/PDMcT/CNT composite. High capacitance value (289.4 F g(-1)) was also determined for this composite, indicating that all materials, PAni, PDMcT and CHT, remain active during the charge-discharge cycling. The reduction in the capacitance after 100 cycles was found to be less than 25%. The capacitive behavior of all materials was confirmed by impedance analysis. (c) 2009 Elsevier Ltd. All rights reserved.