EP0509451A1
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Improved solid electrolytic capacitors and method for manufacturing the same
Assignee: Panasonic Holdings Corp
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Filing: 1992-04-14
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Granted: —
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Expires: 2012-04-14
Abstract
Abstract The invention relates to solid electrolytic capacitors (10) which comprise a valve metal member (12) having a dielectric oxide film (14) and a conductive underlying layer (16) formed on the member in this order, and a conductive polymer film (18) formed on the conductive underlying layer (16). The conductive polymer film (18) is formed by electrolytic polymerization of a polymerizable monomer contained in a system containing the monomer and a support electrolyte consisting of a compound having at least one nitro group. By this, high temperature stability of the capacitor is significantly improved. Alternatively, the electrolytic polymerization may be effected in a system which comprises a monomer, a support electrolyte and a phenol or phenoxide derivative having at least one nitro group. Methods for fabricating such capacitors are also described.
Inventors
- 👤 Yasuo Kudoh
- 👤 Masao Fukuyama
- 👤 Toshikuni Kojima
- 👤 Norishige Nanai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 18:11
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/004; H01G9/022; H01G9/025; H01G9/008; H01G9/012; H01G9/028; Y; Y10; Y10T; Y10T29/00; Y10T29/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
124 words
A solid electrolytic capacitor which comprises a valve metal member having a dielectric oxide film and a conductive underlying layer formed thereon in this order, and a conductive polymer film which is formed on the conductive underlying layer and is obtained by electrolytic polymerization of a polymerizable monomer, the electrolytic polymerization being effected in an electrolytic polymerization system which comprises, in a liquid medium, the polymerizable monomer and a support electrolyte which consists essentially of a compound having at least one nitro group, or in an electrolytic polymerization system which comprises, in a liquid medium, the polymerizable monomer, a support electrolyte, and a phenol or phenoxide derivative having at least one nitro group, thereby forming the conductive polymer film on the conductive underlying layer.
Claim 2
Dependent Claim
34 words
The solid electrolytic capacitor according to Claim 1, wherein said compound of the first-mentioned polymerization system has at least one nitro group and at least one sulfo group or at least one carboxyl group.
Claim 3
Dependent Claim
31 words
The solid electrolytic capacitor according to Claim 2, wherein said compound is a member selected from the group consisting of arylnitrosulfonic acids and salts thereof, and arylnitrocarboxylic acids and salts thereof.
Claim 4
Dependent Claim
31 words
The solid electrolytic capacitor according to Claim 1, wherein said support electrolyte in the first-mentioned polymerization system is used in an amount of from 0.01 to 0.5 moles/liter of the system.
Claim 5
Dependent Claim
23 words
The solid electrolytic capacitor according to Claim 1, wherein said valve metal member is selected from the group consisting of aluminium and tantalum.
Claim 6
Dependent Claim
18 words
The solid electrolytic capacitor according to Claim 1, wherein said conductive underlying layer is a manganese oxide layer.
Claim 7
Dependent Claim
27 words
The solid electrolytic capacitor according to Claim 1, wherein the polymerizable monomer is a member selected from the group consisting of pyrrole, pyrrole derivatives and mixtures thereof.
Claim 8
Dependent Claim
48 words
The solid electrolytic capacitor according to Claim 1, wherein the support electrolyte of the second-mentioned polymerization system is a member selected from the group consisting of naphthalenesulfonates having an alkyl substituent having from 1 to 12 carbon atoms and alkyl phosphates having from 2 to 12 carbon atoms.
Claim 9
Dependent Claim
19 words
The solid electrolytic capacitor according to Claim 1, wherein said derivative used in the second-mentioned polymerization system is nitrophenol.
Claim 10
Dependent Claim
25 words
The solid electrolytic capacitor according to Claim 1, wherein said derivative is used in an amount of from 0.001 to 0.5 moles/liter of the system.
Claim 11
Independent Claim
106 words
A method for fabricating the solid electrolytic capacitor which comprises providing a valve metal member having a dielectric oxide film and a conductive underlying layer formed thereon, and subjecting the valve metal member to electrolytic polymerization of a polymerizable monomer in a system which comprises, in a liquid medium, the polymerizable monomer and a support electrolyte consisting essentially of a compound having at least one nitro group, or in a system which comprises, in a liquid medium, the polymerizable monomer, a support electrolyte and a phenol or phenoxide derivative having at least one nitro group, thereby forming a conductive polymer film on the conductive underlying layer.
Claim 12
Dependent Claim
12 words
The method according to Claim 11, wherein the liquid medium is water.
References Cited (Backward Citations)
EP0295676A2
Cited
EP0336299A2
Cited
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