An electrolytic capacitor includes a capacitor element and a solution containing a solute. The capacitor element includes: an anode foil provided with a dielectric layer on the anode foil; a cathode foil disposed to face the anode foil; and a conductive polymer layer disposed between the anode foil and the cathode foil. The cathode foil is provided with a first layer disposed on the cathode foil, the first layer including at least one selected from the group consisting of carbon, nickel, a nickel compound, titanium, and a titanium compound. The conductive polymer layer includes a conductive polymer in contact with at least a part of a surface of the first layer. The cathode foil has a roughened surface, and the roughened surface of the cathode foil has a surface expansion rate ranging from 1.5 cm.sup.2/cm.sup.2 to 500 cm.sup.2/cm.sup.2, inclusive.

An electrode foil for an electrolytic capacitor includes a base material containing a valve metal and a dissimilar metal composite layer covering a surface of the base material. The dissimilar metal composite layer includes a mixed region in which a first metal and a second metal are mixed. The second metal is different from the first metal. The mixed region constitutes at least 50% of the dissimilar metal composite layer in a thickness-wise direction of the dissimilar metal composite layer. Each of a content M1 of the first metal and a content M2 of the second metal with respect to all metals in the mixed region is 1 atomic % or more.

A solid electrolytic capacitor element includes an anode foil that includes a porous part in a surface layer of the anode foil, a dielectric layer,and a cathode part. The cathode part includes a solid electrolyte layer that covers the at least a part of the dielectric layer and a cathode lead-out layer that covers at least a part of the solid electrolyte layer. The anode foil includes a first part that is a cathode forming part where the solid electrolyte layer is formed and a second part where the solid electrolyte layer is not formed. And the anode foil includes a dense part in the surface layer in at least one of the first part and the second part. The dense part has a porosity smaller than a porosity of the porous part. The second part includes at least an anode part including an end part of the anode foil opposite to the first part.

A solid electrolytic capacitor element includes an anode body including a porous part, a dielectric layer, and a cathode part. The cathode part includes a solid electrolyte layer covering the dielectric layer. The anode body includes a first anode body part on which the solid electrolyte layer is disposed and a second anode body part on which the solid electrolyte layer is not disposed. The solid electrolyte layer includes a first solid electrolyte layer disposed in the porous part and a second solid electrolyte layer disposed outside the porous part. When a length of the first anode body part in a longitudinal direction thereof is defined as a length L, a thickness of the second solid electrolyte layer in a first region is more than or equal to 1 μm. The first region is a region between boundary between the first anode body part and the second anode body part and a position located away from boundary in a length 0.05L in the first anode body part.

A solid electrolytic capacitor capable of improving manufacturing yield is provided. A solid electrolytic capacitor according to one aspect of the present disclosure includes an anode lead-out wire and a capacitor element in which the anode lead-out wire is embedded. The cross section of at least a part of the anode lead-out wire in a direction in which the anode lead-out wire is extended has a flat shape, and a recess provided in a central part, a first linear part that is extended outward from one side of the recess, and a second linear part that is extended outward from another side of the recess are formed in at least one of an upper surface and a lower surface of the anode lead-out wire having the flat shape.

A solid electrolytic capacitor capable of improving manufacturing yield is provided. A solid electrolytic capacitor according to one aspect of the present disclosure includes an anode lead-out wire and a capacitor element in which the anode lead-out wire is embedded. The cross section of at least a part of the anode lead-out wire in a direction in which the anode lead-out wire is extended has a flat shape, and a recess provided in a central part, a first linear part that is extended outward from one side of the recess, and a second linear part that is extended outward from another side of the recess are formed in at least one of an upper surface and a lower surface of the anode lead-out wire having the flat shape.

An electrode foil having high capacitance per unit volume is provided. The electrode foil is an electrode foil for an electrolytic capacitor. The electrode foil is an electrode foil extending in a longitudinal direction and having a width direction orthogonal to the longitudinal direction, the electrode foil including an enlarged surface portion on a surface of the electrode foil, wherein a crack is formed in the enlarged surface portion in a direction oblique to the width direction.

An electrochemical device which is an alkali metal battery or an alkaline earth metal battery, wherein only a positive electrode is an electrode having a perfluoropolyether group-containing compound in a surface thereof.

An electrochemical device which is an alkali metal battery or an alkaline earth metal battery, wherein only a positive electrode is an electrode having a perfluoropolyether group-containing compound in a surface thereof.

Fabricating a capacitor includes performing an oxide formation operation on a sheet of material. The oxide formation operation forms an anode metal oxide on an anode metal. A thermal compression is performed on the sheet of material after the oxide formation operation is performed. The thermal compression applies thermal energy to the sheet of material while applying pressure to the sheet of material. After the thermal compression, the capacitor is assembled such that at least one electrode in the capacitor includes at least a portion of the sheet of material.