Stability study of polypyrrole and application to highly thermostable aluminum solid electrolytic capacitor

• Published in: Synthetic metals Vol. 66; no. 2; pp. 157 - 164
• Main Authors: Kudoh, Yasuo, Fukuyama, Masao, Yoshimura, Susumu
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30.09.1994; Amsterdam Elsevier Science; New York, NY
• Subjects: Application fields; Applied sciences; Capacitor; Capacitors. Resistors. Filters; Electrical engineering. Electrical power engineering; Exact sciences and technology; Polymer industry, paints, wood; Polypyrrole; Stability; Technology of polymers; Various equipment and components; Capacitor; Polypyrrole; Stability; Electrical conductivity; Electrical properties; Use; Thermooxidative degradation; Electrolytic capacitor; Experimental study; Thermal stability; Sulfonate; Reaction mechanism; Doped polymer; Kinetics; Electrical conductor; Pyrrole polymer; Electrical characteristic
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/0379-6779(94)90093-0

This paper describes the stability of electropolymerized polypyrrole and a highly thermostable aluminum solid electrolytic capacitor in which polypyrrole is applied as an electrolyte. We found that polypyrrole doped with tri-i-propylnaphthalenesulfonate (PPy/TIPNS) shows excellent thermostability and its conductivity decay stems from the addition reaction of oxygen followed by thermal decomposition in which oxygen participates. On the basis of these results, we developed a highly thermostable aluminum solid electrolytic capacitor which is composed of an etched and anodized aluminum foil anode covered with electropolymerized PPy/TIPNS and is hermetically sealed. The capacitor continuously functioned for more than 3600 h at 150 °C without any deterioration. Moreover, the capacitor also showed ideal impedance-frequency characteristics comparable to those of the multilayer ceramic capacitor and flat temperature characteristics in the wide range of −50 to 150 °C.