Improvement of capacitive performances of symmetric carbon/carbon supercapacitors by addition of nanostructured polypyrrole powder

A nanostructured polypyrrole powder was synthesized in a previous work from the oxidation of pyrrole by a nanostructured MnO2 powder used simultaneously as an oxidizing agent and a sacrificial template in a redox heterogeneous mechanism. In this study, this original PPy powder was used as an active additive material with different ratio in carbon/carbon symmetrical supercapacitors whose performances were studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) using a Swagelok-type cell. From the EIS spectra, the complex capacitance was extracted using a model involving two Cole-Cole type complex capacitances linked in series. The specific capacitance values evaluated by EIS and cyclic voltammetry are in a good agreement between them. The results show that the addition of nanostructured polypyrrole powder improves significantly the specific capacitance of the carbon electrode and consequently the performances of carbon/carbon supercapacitors. The original and versatile synthesis method used to produce this polypyrrole powder appears to be attractive for large scale production of promising additives for electrode materials of supercapacitors.