A capacitor and methods of processing an anode metal foil are presented. The capacitor includes a housing, one or more anodes disposed within the housing, one or more cathodes disposed within the housing, one or more separators disposed between an adjacent anode and cathode, and an electrolyte disposed around the one or more anodes, one or more cathodes, and one or more separators within the housing. The one or more anodes each include a metal foil that includes a first plurality of tunnels through a thickness of the metal foil in a first ordered arrangement, the first ordered arrangement being a close packed hexagonal array arrangement, and having a first diameter, and a second plurality of tunnels through the thickness of the metal foil having a second ordered arrangement and a second diameter greater than the first diameter.

Anode foil, preferably aluminum anode foil, is etched using a process of treating the foil in an electrolyte bath composition comprising a perfluoroalkylsulfonate, a sulfate, a halide, and an oxidizing agent. The anode foil is etched in the electrolyte bath composition by passing a direct current charge through the bath. The etched anode foil is suitable for use in an electrolytic capacitor.

Anode foil, preferably aluminum anode foil, is etched using a process of treating the foil in an electrolyte bath composition comprising a perfluoroalkylsulfonate, a sulfate, a halide, and an oxidizing agent. The anode foil is etched in the electrolyte bath composition by passing a direct current charge through the bath. The etched anode foil is suitable for use in an electrolytic capacitor.

An electrode foil for an electrolytic capacitor includes an anode body foil having a porous part, and a dielectric layer covering a surface of a metal framework constituting the porous part. The dielectric layer includes a first layer containing an oxide of a second metal, the second metal being different from a first metal contained in the metal framework. An underlayer that is continuous with the first layer is provided between the metal framework and the first layer. The underlayer contains phosphorus and carbon.

An electrode foil for an electrolytic capacitor includes an anode body foil having a porous part, and a dielectric layer covering a surface of a metal framework constituting the porous part. The dielectric layer includes a first layer containing an oxide of a second metal, the second metal being different from a first metal contained in the metal framework. An underlayer that is continuous with the first layer is provided between the metal framework and the first layer. The underlayer contains phosphorus and carbon.

An electrode foil for an electrolytic capacitor includes a metal foil having a porous part, and a dielectric layer covering a surface of a metal framework constituting the porous part. The dielectric layer includes a first layer containing an oxide of a second metal different from a first metal contained in the metal framework. The first layer has a thickness T1. The first layer contains at least one kind of additive element selected from the group consisting of carbon, phosphorus, boron, and nitrogen. The first layer includes a first region from an outer surface of the first layer to a center of the first layer in a thickness direction, and a second region from the center to an inner surface of the first layer. A content of the at least one kind of additive element in the second region is greater than a content of the at least one kind of additive element in the first region.

An electrode foil for an electrolytic capacitor includes a metal foil having a porous part, and a dielectric layer covering a surface of a metal framework constituting the porous part. The dielectric layer includes a first layer containing an oxide of a second metal different from a first metal contained in the metal framework. The first layer has a thickness T1. The first layer contains at least one kind of additive element selected from the group consisting of carbon, phosphorus, boron, and nitrogen. The first layer includes a first region from an outer surface of the first layer to a center of the first layer in a thickness direction, and a second region from the center to an inner surface of the first layer. A content of the at least one kind of additive element in the second region is greater than a content of the at least one kind of additive element in the first region.

In an embodiment, a capacitor includes a winding element having a diameter of more than 10 mm, at least two tabs electrically contacted with an anode foil and at least two tabs electrically contacted with a cathode foil, wherein the capacitor is a hybrid polymer aluminum electrolytic capacitor, wherein the winding element is arranged inside a can having a can bottom, and wherein the can comprises a corrugation which fixes the winding element.

In an embodiment, a capacitor includes a winding element having a diameter of more than 10 mm, at least two tabs electrically contacted with an anode foil and at least two tabs electrically contacted with a cathode foil, wherein the capacitor is a hybrid polymer aluminum electrolytic capacitor, wherein the winding element is arranged inside a can having a can bottom, and wherein the can comprises a corrugation which fixes the winding element.

An electrolytic capacitor includes a capacitor element, an exterior body that seals the capacitor element, and an external electrode. The capacitor element includes an anode foil, a dielectric layer, and a cathode part. The anode foil includes an anode lead-out part and a cathode forming part. The anode lead-out part has a first end of the anode foil. The cathode forming part has a second end of the anode foil. The dielectric layer is disposed on a surface of the cathode forming part. The cathode part covers at least part of the dielectric layer. The first end in the anode lead-out part protrudes from an end surface of the exterior body. At least part of the first end is in contact with the external electrode.