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US 6,987,663 B2Granted
Electrolytic capacitors with a polymeric outer layer
AssigneeH.C. Starck GmbH
InventorsUdo Merker, Klaus Wussow, Friedrich Jonas
Life of this patent
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Abstract
Electrolytic capacitors having low equivalent series resistance and low leakage current are described. The electrolytic capacitors include a solid electrolyte layer of a conductive material in particular a conductive polymer, and an outer layer that includes binders, polymeric anions and conductive polymers (e.g., polythiophenes). Also described is a method of preparing electrolytic capacitors that involves forming the conductive polymer of the solid electrolyte layer in situ by means of chemical oxidative polymerization or electrochemical polymerization. Electronic circuits that include the electrolytic capacitors are also described.
Claims30
An electrolytic capacitor comprising:
- (a) a porous electrode body comprising an electrode material, said porous electrode body having a surface;
- (b) a dielectric material covering the surface of the porous electrode body, said dielectric material having a surface;
- (c) a solid electrolyte comprising a conductive material preferably a conductive polymer that at least partially covers the surface of said dielectric material, said solid electrolyte having a surface;
- (d) a layer covering the entire external surface or a portion of the external surface of the porous electrode body thereby covering at least a portion of the surface of said solid electrolyte and optionally a portion of the surface of said dielectric material, said layer comprising at least one polymeric anion, and at least one member selected from the group consisting of polyaniline, optionally substituted poylaniline and polythiophene, said polythiophene having recurring units selected from the group consisting of general formula (I), general formula (II) and combinations thereof,
- wherein
- A represents a member selected from the group consisting of C1 to C5 alkylene radical and C1 to C5 alkylene radical substituted with at least one member selected from the group consisting of alkyl, cycloalkyl, aryl, halogen, ether, thioether, disulphide, sulphoxide, sulphone, sulphonate, amino, aldehyde, keto, carboxylic acid ester, carboxylic acid, carbonate, carboxylate, cyano, alkylsilane, alkoxysilane and carboxylamide,
- R represents a member selected from the group consisting of linear or branched C1 to C18 alkyl radical, C5 to C12 cycloalkyl radical, C6 to C14 aryl radical, C7 to C18 aralkyl radical, C1 to C4 hydroxyalkyl radical and hydroxyl radical,
- x represents an integer from 0 to 8, and provided that if x is at least 2, each R may be the same or different,
- wherein layer (d) further comprises at least one binder.
6 more elements
A method of preparing an electrolytic capacitor comprising,
- (a) a porous electrode body comprising an electrode material, said porous electrode body having a surface;
- (b) a dielectric material covering the surface of the porous electrode body, said dielectric material having a surface;
- optionally coated with further layers
- (c) a solid electrolyte comprising a conductive polymer that at least partially covers the surface of said dielectric material, said solid electrolyte having a surface;
- (d) a layer covering at least a portion of the surface of said solid electrolyte and optionally a portion of the surface of said dielectric material, said layer comprising at least one polymeric anion, and at least one member selected from the group consisting of polyaniline and polythiophene, said polythiophene having recurring units selected from the group consisting of general formula (I), general formula (II) and combinations thereof,
- wherein
- A represents a member selected from the group consisting of C1 to C5 alkylene radical and C1 to C5 alkylene radical substituted with at least one member selected from the group consisting of alkyl, cycloalkyl, aryl, halogen, ether, thioether, disulphide, sulphoxide, sulphone, sulphonate, amino, aldehyde, keto, carboxylic acid ester, carboxylic acid, carbonate, carboxylate, cyano, alkylsilane, alkoxysilane and carboxylamide,
- R represents a member selected from the group consisting of linear or branched C1 to C18 alkyl radical, C5 to C12 cycloalkyl radical, C6 to C14 aryl radical, C7 to C18 aralkyl radical, C1 to C4 hydroxyalkyl radical and hydroxyl radical,
- x represents an integer from 0 to 8, and provided that if x is at least 2, each R may be the same or different,
- wherein layer (d) further comprises at least one binder, said process comprising:
- (I) forming said solid electrolyte (c) by a method selected from the group consisting of,
- applying, together or in succession, with or without in the form of a solution, to said surface of said dielectric material,
- precursors of conductive polymers,
- at least one oxidizing agent, and
- optionally counterions, and
- polymerizing the applied materials by means of chemical oxidation at a temperature of −10° C. to 250° C., and
- applying, together or in succession, with or without in the form of a solution, to said surface of said dielectric material,
- precursors of conductive polymers, and
- counterions, and
- polymerizing electrochemically the applied materials at a temperature of −78° C. to 250° C.;
- and
- (II) forming layer (d) by applying, to at least a portion of the external surface of said solid electrolyte and optionally a portion of the surface of said dielectric material, a dispersion comprising said binder, at least one polymeric anion, and at least one member selected from the group consisting of optionally substituted polyaniline and polythiophene, said polythiophene having recurring units selected from the group consisting of general formula (I), general formula (II) and combinations thereof.
19 more elements
Dependencies are inferred from the claim text.