Synthesis and Electrochemical Characterization of Polypyrrole/Sodium p-Toluenesulfonate Biofilms Supported on Cassava Starch Conductive Polymers for Applications in Electrical Charge Accumulators

Abstract

The aim of this study is to evaluate how the number of dopants in the cassava starch polymer and the oxidation potential of the cathode influence the electrical energy accumulation properties. Materials are synthesized by two stages: In the stage I, synthesis of the conductive polymer was performed from cassava starch, plasticizers and lithium perchlorate; later, in the stage II, salt-doped polypyrrole was electrochemically synthesized. Sodium ptoluenesulfonate and lithium perchlorate were used as doping salts. Characterization of materials were performed by Electrochemical Impedance Spectroscopy (EIS) and cyclic voltammetry. The best results were obtained for assays 1 and 4 constituted by1.5 g of starch and 0.5 V for the cathode and 3 g of starch and 0.7 V for the cathode, respectively. Respective specific charge capacities and specific energies were 3.765×10-4 Ah/kg and 3.477×10-5 Wh/kg for the assay 1 and 2.234×10-4 Ah/kg and 9.095×10-5 Wh/kg for the assay 4. These responses are associated with a higher values of electrical conductivity for the assay 1 and 4 by EIS, favoring the mobility of the charges within the materials; Finally, the stability of assay voltammograms indicates how their properties can be maintained at the time.