Polythiophene (PTh) was prepared by chemical oxidation and cobalt nanoparticles (Co-nps) by modified polyol process. The nanocomposites were prepared by mixing mechanically the PTh and Co-nps in the weight percentage, PTh_100-xCo_x, x = 10, 20, 30, 40 and 50. XRD of these nanocomposites showed amorphous nature. DC conductivity variation with temperature in the range from 303 K to 473 K indicated semiconducting behavior. Conduction mechanism was found to be small polaron hopping at high temperature and 3D variable range hopping at low temperatures. Conductivity and activation energy values points out that addition of Co-nps to the PTh induces electrically insulating effect. The SQUID magnetometer measurements at 10 K and 300 K showed perfect ferromagnetic nature and magnetically softness of the composites. Cyclic voltammetry study has been carried out on all the composites and in that a composite having 30% of Co-nps measured Specific Capacitance (SC) value as high as 583.20 F/g. This can be the best candidate for capacitor applications. This is for the first time that PTh-Co nanocomposites have been thoroughly probed for structure, conduction mechanism, magnetization and supercapacitor applications.

Keywords: Polythiophene; Nanocomposites; Conductivity; Magnetization; Voltammetry;