Conductive polymer and solid electrolytic capacitor using same

Abstract

The conductive polymer of the present invention is prepared by means of oxidation polymerization. On the matrix of the conductive polymer, at least one organic sulfonate formed by an anion of an organic sulfonic acid and a cation of other than transition metals is coated. Alternatively, in the matrix of the conductive polymer, at least one organic sulfonate formed by an anion of an organic sulfonic acid and a cation of other than transition metals is included. The conductive polymer of the present invention is excellent in the conductivity, heat resistance and moisture resistance. By using it as a solid electrolyte, a reliable solid electrolytic capacitor can be prepared which is unlikely to decrease the properties when being kept in a hot and humid condition.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a conductive polymer and a solid electrolytic capacitor using the conductive polymer as a solid electrolyte. BACKGROUND OF THE INVENTION [0002] Conductive polymers have a high conductivity, which are used as solid electrolytes of a solid electrolytic capacitor such as aluminum capacitors and tantalum capacitors. [0003] As a conductive polymer used therefor, ones are often used which are synthesized by subjecting thiophenes or the derivatives thereof to chemical oxidation polymerization or electrolysis oxidation polymerization. [0004] In carrying out the chemical oxidation polymerization, an organic sulfonic acid is generally used as a dopant, and ammonium persulfate, hydrogen peroxide, and transition metal salts are generally used as an oxidant. Generally, in case where a process of a chemical oxidation polymerization is used to synthesize a conductive polymer, especially by using transition metal salts as an oxidant, it...

AI Technical Summary

Benefits of technology

[0007] In view of the objectives of the prior art, the present invention provides a conductive polymer excellent in conductivity, heat resistance and moisture resistance, which is less changeable in the electric conductivity when being kept in a hot and humid condition, so as to avoid the decomposition in a hot condition. Also, the objective of the present invention is to use the conductive polymer as a solid electrolyte, to provide a reliable solid electrolytic capacitor which less decreases the properties in a hot and humid condition.

[0010] The conductive polymer of the present invention is excellent in conductivity, heat resistance, and moisture resistance, which less decreases the electric conductivity when being kept in a hot and humid condition and to decompose in a hot condition. Also, the solid electrolyte capacitor of the present invention by using the conductive polymer as a solid electrolyte is reliable because it has the properties less decreased when being kept in a hot and humid condition.

[0026] The organic sulfonate treated conductive polymer of the present invention, as polymerized and treated by the organic sulfonate, is excellent in conductivity, heat resistance and moisture resistance, is less in decreasing the electric conductivity when being kept in a hot and humid condition, and is less in being decomposed in a hot condition. Thus, it is reliable so that it can be useful in cathode layers of a capacitor, electrodes of a battery, electrical conductive agent for an antistatic sheet and so on. Especially, the solid electrolytic capacitor using the organic sulfonate treated conductive polymer of the present invention as a solid electrolyte is excellent in electric properties.

Problems solved by technology

However, such a washing process causes the dopant to be de-doped, decreasing the electric conductivity of the conductive polymer.

However, the conductive polymer in which an excessive amount of an organic sulfonic acid remains is apt to generate SO3 that is toxic when it is kept in hot condition than the conductive polymer which is washed to remove an excessive amount of an organic sulfonic acid, because the excessive (free) organic sulfonic acid is apt to be decomposed in a hot condition.