Abstract: A technique for forming a cathode of a wet electrolytic capacitor is provided. The cathode contains a metal substrate having a roughened surface and a conductive coating that contains a substituted polythiophene. The degree of surface contact between the conductive coating and the roughened surface is enhanced in the present invention by selectively controlling the manner in which the conductive coating is formed. More particularly, the conductive coating is formed by applying a precursor solution to the roughened surface that includes both a precursor thiophene monomer and an oxidative catalyst. Contrary to techniques in which either the monomer or catalyst is applied separately and initially contacts the metal surface, the presence of the monomer and catalyst within the same solution allows polymer chains to grow immediately adjacent to the surface of the metal substrate and within the pits.

Abstract: A method for forming an electrolytic capacitor is disclosed. The method includes forming a conductive polymer coating over the dielectric layer by polymerizing a monomer in the presence of an oxidative polymerization catalyst. The conductive polymer coating is formed by dipping the anode in a polymerization solution comprising the monomer, the oxidative polymerization catalyst, and a polar solvent. The polymerization solution has a temperature of less than about 20° C. Cooling the polymerization solution further stabilizes the polymerization solution and prevents premature polymerization of the monomer(s). Thus, the resulting conductive polymer layer can be more intimately positioned with respect to the anode. As a result, the formed capacitor can exhibit better performance.

Abstract: A capacitor assembly that includes an electrolytic capacitor that contains an anode body, dielectric overlying the anode, and a solid electrolyte overlying the dielectric is provided. An anode lead is also electrically connected to the anode body and extends in a longitudinal direction therefrom. The anode lead is connected to an “upstanding” portion of a leadframe. Among other things, this helps to limit substantial horizontal movement of the lead and thereby improve the mechanical robustness of the part. The capacitor and leadframe are enclosed and hermetically sealed within a ceramic housing in the presence of an inert gas. It is believed that the ceramic housing is capable of limiting the amount of oxygen and moisture supplied to the conductive polymer of the capacitor. In this manner, the solid electrolyte (e.g., conductive polymer) is less likely to undergo a reaction in high temperature environments, thus increasing the thermal stability of the capacitor assembly.

Abstract: An electrolytic capacitor that contains an anodically oxidized anode that is incorporated with an additional metallic element is provided. More specifically, the metallic element is built into the valve metal pentoxide of the dielectric layer. In one particular embodiment, the addition of the metallic element results in a niobium pentoxide dielectric that contains closely packed units of O atoms, Nb6 octahedral, and metal atoms (“A”) that serve as counter cations. The use of relatively small electropositive metal atoms (A?) helps fill the tetrahedral (e.g., Al, Si, Ti, Mg, or Mn), octahedral (e.g., Nb, V, Mg, or Mn) and trigonal bipyramid (e.g., V, Nb) interstices of the crystals. The stability of capacitor leakage current may be improved by variation in this crystal structure.

Abstract: An electrolytic capacitor anode etched with an organic acid prior to anodic oxidation of the anode to create the dielectric layer. Without intending to be limited by theory, it is believed that the organic acid can etch away at least a portion of any oxides on the anode. This provides a relatively uniform surface for the creation of the dielectric, which in turn leads to a dielectric layer having a substantially uniform thickness and homogeneous amorphous structure and thus improved leakage current and stability. The organic acid may also have other residual benefits, such as removing any metallic impurities from the surface of the anode.

Abstract: An electrolytic capacitor anode treated with a surfactant during anodic oxidation is provided. Without intending to be limited by theory, it is believed that the surfactant may lower the surface tension of an electrolyte, which inhibits the clustering of grown oxides and allows the dielectric layer to become more homogeneous and uniformly spread over the anode body. The resulting dielectric layer may thus have a substantially homogeneous thickness, smooth surface, and improved leakage current stability.

Abstract: The present invention relates to a method of manufacturing a porous article, in particular the anode of a valve action material based solid state capacitor, comprising the steps of combining a water soluble polymeric binder and particulate material before pressing the particulate material and the subsequent step of removing the binder form the pressed pellet. Thus, the present invention also relates to a method of removing a water soluble polymeric binder from pressed particulate material and to a composition comprising a water soluble polymeric binder for forming the anode of a valve action material based solid state capacitor.

Abstract: An electrolytic capacitor anode etched with an organic acid prior to anodic oxidation of the anode to create the dielectric layer. Without intending to be limited by theory, it is believed that the organic acid can etch away at least a portion of any oxides on the anode. This provides a relatively uniform surface for the creation of the dielectric, which in turn leads to a dielectric layer having a substantially uniform thickness and homogeneous amorphous structure and thus improved leakage current and stability. The organic acid may also have other residual benefits, such as removing any metallic impurities from the surface of the anode.

Abstract: An electrolytic capacitor anode treated with a surfactant during anodic oxidation is provided. Without intending to be limited by theory, it is believed that the surfactant may lower the surface tension of an electrolyte, which inhibits the clustering of grown oxides and allows the dielectric layer to become more homogeneous and uniformly spread over the anode body. The resulting dielectric layer may thus have a substantially homogeneous thickness, smooth surface, and improved leakage current stability.

Abstract: An electrolytic capacitor that contains an anodically oxidized anode that is incorporated with an additional metallic element is provided. More specifically, the metallic element is built into the valve metal pentoxide of the dielectric layer. In one particular embodiment, the addition of the metallic element results in a niobium pentoxide dielectric that contains closely packed units of O atoms, Nb6 octahedral, and metal atoms (“A”) that serve as counter cations. The use of relatively small electropositive metal atoms (A?) helps fill the tetrahedral (e.g., Al, Si, Ti, Mg, or Mn), octahedral (e.g., Nb, V, Mg, or Mn) and trigonal bipyramid (e.g., V, Nb) interstices of the crystals. The stability of capacitor leakage current may be improved by variation in this crystal structure.

Abstract: A method for forming an electrolytic capacitor is disclosed. The method includes forming a conductive polymer coating over the dielectric layer by polymerizing a monomer in the presence of an oxidative polymerization catalyst. The conductive polymer coating is formed by dipping the anode in a polymerization solution comprising the monomer, the oxidative polymerization catalyst, and a polar solvent. The polymerization solution has a temperature of less than about 20° C. Cooling the polymerization solution further stabilizes the polymerization solution and prevents premature polymerization of the monomer(s). Thus, the resulting conductive polymer layer can be more intimately positioned with respect to the anode. As a result, the formed capacitor can exhibit better performance.

Abstract: The present invention relates to a solid state capacitor having a conductive polymer cathode layer counter electrode comprising acrylate binder and a method for its manufacture. In particular the present invention relates to a solid state capacitor comprising: providing a porous anode body of valve action material; forming a dielectric layer on said porous body; forming a cathode layer in contact with said dielectric layer, which cathode layer comprises a conductive polymer and an acrylic binder; and providing an anode terminal in electrical connection with the porous body anode and a cathode terminal in electrical connection with the cathode layer and a method for its manufacture.

Abstract: A method for forming an electrolytic capacitor is disclosed. The method includes forming a conductive polymer coating by polymerizing a monomer in the presence of less than a stoichiometric amount of an oxidative polymerization catalyst. The present inventor has found that the use of less than the stoichiometric amount of the oxidative polymerization catalyst per mole of monomer can slow the polymerization of the monomer, creating oligomers that are shorter in length than if fully polymerized into a polymer. Without wishing to be bound by theory, it is believed that these shorter oligomers provide better penetration into the porous anode. Thus, the resulting conductive polymer layer can be more intimately positioned with respect to the anode. As a result, the formed capacitor can exhibit better performance.

Abstract: An electrolytic capacitor containing an anode and solid electrolyte overlying the anode is provided. The capacitor may also include a barrier layer that overlies the solid electrolyte to help protect the capacitor from its working environment. More specifically, the barrier layer may include a three-dimensional crosslinked network that provides excellent adhesion to the underlying layers, and also improved barrier properties to moisture. In this manner, the barrier layer can enable the electrolytic capacitor to increase it performance in relatively high humidity and/or high temperature environments.

Abstract: The present invention concerns the field of solid state capacitors and is directed more particularly to a method for manufacturing solid state electrolytic capacitors formed from porous conductive metal oxide anode bodies and having a cathode layer of conducting polymer, and capacitors thereby formed. There is disclosed a solid state capacitor comprising a porous anode body, a dielectric layer formed on surfaces of the porous anode body and a cathode layer formed on the dielectric layer, characterised by the combination of the anode body being formed from an electrically conducting ceramic material and the cathode layer being formed from an electrically conductive polymer material. The conducting ceramic material may be a metal oxide or nitride.

Abstract: An electrolytic capacitor containing a protective adhesive layer positioned between the dielectric layer and the solid electrolyte layer (e.g., a conductive polymer layer, manganese dioxide) is generally disclosed. The protective adhesive layer can include a polymer having a repeating unit with a functional hydroxyl group, such as poly(vinyl alcohol). For instance, the polymer can be at least 90 mole % hydrolyzed. The polyvinyl alcohol can be a co-polymer of vinyl alcohol and a monomer, such as an acrylic ester like a methacrylic ester (e.g., methyl methacrylate).

Abstract: An electrolytic capacitor containing an anode and solid electrolyte overlying the anode is provided. The capacitor may also include a barrier layer that overlies the solid electrolyte to help protect the capacitor from its working environment. More specifically, the barrier layer may include a three-dimensional crosslinked network that provides excellent adhesion to the underlying layers, and also improved barrier properties to moisture. In this manner, the barrier layer can enable the electrolytic capacitor to increase it performance in relatively high humidity and/or high temperature environments.

Abstract: An electrolytic capacitor containing a protective adhesive layer positioned between the dielectric layer and the solid electrolyte layer (e.g., a conductive polymer layer, manganese dioxide) is generally disclosed. The protective adhesive layer can include a polymer having a repeating unit with a functional hydroxyl group, such as poly(vinyl alcohol). For instance, the polymer can be at least 90 mole % hydrolyzed. The polyvinyl alcohol can be a co-polymer of vinyl alcohol and a monomer, such as an acrylic ester like a methacrylic ester (e.g., methyl methacrylate).

Abstract: A method for forming an electrolytic capacitor is disclosed. The method includes forming a conductive polymer coating by polymerizing a monomer in the presence of less than a stoichiometric amount of an oxidative polymerization catalyst. The present inventor has found that the use of less than the stoichiometric amount of the oxidative polymerization catalyst per mole of monomer can slow the polymerization of the monomer, creating oligomers that are shorter in length than if fully polymerized into a polymer. Without wishing to be bound by theory, it is believed that these shorter oligomers provide better penetration into the porous anode. Thus, the resulting conductive polymer layer can be more intimately positioned with respect to the anode. As a result, the formed capacitor can exhibit better performance.