Sumanta Sahoo

Investigations on doping of poly(3-methyl-thiophene) composites for supercapacitor applications

AbstractZinc ion (Zn2+)-doped poly(3-methyl-thiophene)/multi-walled carbon nano tubes (MWCNT) composites (M-PMT-ZN) and poly(3-methyl-thiophene)/MWCNT composites (M-PMT) were synthesized by in situ chemical oxidative polymerization and investigated as electrode material for supercapacitors. The interactions of Zn2+ ions with sulfur sites on the polymer chains were characterized by Fourier transform infrared spectroscopy. The morphology of the nanocomposites was characterized by scanning electron microscopy and high resolution transmission electron microscopy. The electrochemical properties were investigated using cyclic voltammetry, cyclic charging-discharging tests, and electrochemical impedance spectroscopy in a three-electrode system. Use of M-PMT-ZN resulted in a higher specific capacitance of 235 F/g. The specific capacitance retention after 500 cycles on M-PMT-ZN was also higher compared with that of the M-PMT composite. These results indicate that transition metal ion doping enhances the electrochemical properties of the conducting polymer.

In Situ Synthesis of Graphene/Amine-Modified Graphene, Polypyrrole Composites in Presence of SrTiO3 for Supercapacitor Applications

Composites based on both unmodified and amine-modified graphene were successfully prepared via in situ oxidative polymerization of pyrrole in presence of SrTiO3. To characterize the graphene/amine-modified graphene-polypyrrole-SrTiO3 composite electrodes, cyclic voltammetry test for measuring specific capacitance, cyclic charge discharge test and an ac impedance test were executed. The composite with unmodified graphene showed better specific capacitance but a little lower cyclability compared to that of modified graphene composite. The presence of SrTiO3 ensures the better thermal stability of the composites compared to that of simple graphene–polypyrrole composite.