Carbon/polypyrrole composites for electrochemical capacitors

• Composite materials demonstrated enhanced energy/power characteristics.
• Addition of carbon material improved charge propagation in the electrode material.
• Energy between 3–4 Wh kg−1 with power increase from 20 to 400 W kg−1 was obtained.

Composite materials made ​​of electrically conductive polymer–polypyrrole (PPy) and carbon materials have been prepared and characterized. Oxidative chemical polymerization has been selected as the synthesis method. FeCl3 was used as oxidizing agent. Process was carried out in aqueous acidic medium. Composites were prepared by immersion of selected carbon materials in the solution of monomer and followed by addition of oxidant specimen to subjected solution under vigorous stirring. Obtained composite materials were characterized by three electrochemical methods (cyclic voltammetry, galvanostatic charging/discharging, electrochemical impedance spectroscopy) to determine capacitive parameters for further applications in the electrochemical capacitors. Capacitance of the materials varied in the range of 90–135 F g−1 and has been retained during 5000 cycles of galvanostatic charging/discharging, working in the acidic medium (1 mol L−1 H2SO4 aqueous solutions). Moreover, the measurements confirmed a very high electrochemical stability of polypyrrole supported by carbon materials with a current load of up to 50 A g−1.