Determination of the specific capacitance of conducting polymer/nanotubes composite electrodes using different cell configurations

• Published in: Electrochimica acta Vol. 50; no. 12; pp. 2499 - 2506
• Main Authors: Khomenko, V., Frackowiak, E., Béguin, F.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15.04.2005; Elsevier
• Subjects: Applied sciences; Asymmetric capacitor; Capacitors. Resistors. Filters; Carbon nanotubes; Conducting polymers; Electrical engineering. Electrical power engineering; Exact sciences and technology; Polyaniline; Polypyrrole; Supercapacitor; Various equipment and components; Conducting polymers; Supercapacitor; Carbon nanotubes; Polyaniline; Polypyrrole; Asymmetric capacitor; Scanning electron microscopy; Discharge charge cycle; Composite material; Surface structure; Electrodes; Morphology; Nanocomposite; Critical assessment of techniques for protein structure prediction; Specific capacity; Pyrrole polymer; Aniline polymer; Electrical characteristic
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2004.10.078

Composite materials containing 20 wt.% of multiwalled carbon nanotubes (MWNTs) and 80 wt.% of chemically formed conducting polymers (ECP) as polyaniline (PANI) and polypyrrole (PPy) have been prepared and used for supercapacitor electrodes. The well conducting properties of MWNTs and their available mesoporosity allow a good charge propagation in the composites. Moreover, due to the good resiliency of MWNTs, an excellent stability of the supercapacitor electrodes is observed. It has been shown that the capacitance values for the composites strongly depend on the cell construction. In the case of three electrode cells, extremely high values can be found from 250 to 1100 F/g, however in the two electrode cell much smaller specific capacitance values of 190 F/g for PPy/MWNTs and 360 F/g for PANI/MWNTs have been measured. It highlights the fact that only two-electrode cells allow a good estimation of materials performance in electrochemical capacitors. The applied voltage was found to be the key factor influencing the specific capacitance of nanocomposites. For operating each electrode in its optimal potential range, asymmetric capacitors have been built with PPy/MWNTs as negative and PANI/MWNTs as positive electrodes giving capacitance values of 320 F/g per electrode material.