ポリピロールを用いた固体電解コンデンサの自己修復性の解明

抄録

Current-voltage characteristics of aluminum, tantalum and platinum contacted to a pellet of chemically polymerized polypyrrole were investigated. A typical passivation curve was observed for both an anodic and a cathodic polarizations of aluminum and tantalum, which means a formation of an insulated layer at a contact surface, and there was a resemblance in the I-V curves between the anodic and the cathodic polarization curves of aluminum and tantalum. The current in the I-V characteristics was influenced by ambient moisture, decreasing with increases in relative humidity. Similar behavior has been found for a non-valve metal of platinum, which indicates the passivation is due to a transformation of conductive polypyrrole to an insulator. The deterioration of polypyrrole is assumed to be caused by a synergetic effect of oxygen and water. The self-healing behavior in a solid electrolytic capacitor with polypyrrole electrolyte would be caused mainly by a transforming reaction of a conductive polypyrrole electrolyte to an insulator occuring at the contact surface under applied voltage.