ELECTROCHEMICAL CHARACTERIZATION OF CHEMICALLY SYNTHESIZED POLYTHIOPHENE DERIVATIVES FOR APPLICATION DM ELECTROCHEMICAL CAPACITORS.

摘要

Electronically conducting polymers (ECPs) have been extensively investigated over the past two decades due to their potential applications in energy storage systems, especially when high energy and power densities are required as in electrochemical supercapacitors (1). Among ECPs, those which can be p-and n-doped over a large potential window are the most promising ones due to the high working potential (up to 3 V) of the resulting devices. Polythiophene (PT) can generate such a cell voltage, but the extremely negative potential value of its n-doping process causes some irreversible phenomena, such as electrolyte and polymer degradation. So, many studies have been recently devested to low band gap conducting polymers such as poly diarylcyanovinylene that are n-dopable at less negative potential values (2,3). The present work was aimed to low band gap polymers (see Scheme I) that have been recently systematically characterized after electrodeposition onto carbon paper (3). In order to use conditions closer to industrial applications, it was decided to employ powdered polymers obtained from chemical polymerization of monomers in the presence of an appropriate oxidative agent. The making of large electrodes is then easy to achieve by employing a composite electrode technology comparable to the one used in the industry of lithium batteries and for other conductive polymer-based electrochemical capacitors (4).