Electrolytic capacitor having a high capacitance and a low equivalent series resistance and method for producing the same
View Patent ↗An electrolytic capacitor includes a capacitor element. The capacitor element includes an anode body having a dielectric layer at a surface of the anode body, and an electrolyte covering part of the dielectric layer. The electrolyte contains a conjugated polymer, a polymer dopant having an anionic group, and a metal ion. The amount of the metal ion is less than 1 equivalent, relative to 1 equivalent of the anionic group.
1 . An electrolytic capacitor, comprising a capacitor element, wherein
the capacitor element includes an anode body having a dielectric layer at a surface of the anode body, an electrolyte covering part of the dielectric layer, and a liquid component,
the electrolyte contains a conjugated polymer, a polymer dopant having an anionic group, and a lithium ion,
an amount of the lithium ion is 0.1 equivalents or more and 0.95 equivalents or less, relative to 1 equivalent of the anionic group.
2 . The electrolytic capacitor according to claim 1 , wherein the anionic group of the polymer dopant is contained in the electrolyte in a form of at least one selected from the group consisting of an acid, an anion, and a salt with the lithium ion.
3 . The electrolytic capacitor according to claim 1 , wherein the electrolyte further contains an ammonium ion.
4 . The electrolytic capacitor according to claim 1 , further comprising a separator.
5 . The electrolytic capacitor according to claim 1 , wherein the amount of the lithium ion is 0.1 equivalents or more and 0.9 equivalents or less, relative to 1 equivalent of the anionic group.
6 . The electrolytic capacitor according to claim 1 , wherein the amount of the lithium ion is 0.3 equivalents or more and 0.5 equivalents or less, relative to 1 equivalent of the anionic group.
7 . An electrolytic capacitor, comprising a capacitor element, wherein
the capacitor element includes an anode body having a dielectric layer at a surface of the anode body, an electrolyte covering part of the dielectric layer, and a liquid component,
the electrolyte contains a conjugated polymer, a polymer dopant having an anionic group, and a metal ion,
the electrolyte includes a first portion on the dielectric layer side, and a second portion covering at least part of the first portion, and
a content C1 of the metal ion in the first portion and a content C2 of the metal ion in the second portion satisfy C1>C2.
8 . The electrolytic capacitor according to claim 7 , wherein the second portion does not contain the metal ion.
9 . A method for producing an electrolytic capacitor including a capacitor element that includes an anode body having a dielectric layer on a surface of the anode body, and an electrolyte covering part of the dielectric layer, the method comprising:
a step of preparing a liquid mixture containing a conjugated polymer, a first polymer dopant having an anionic group, and a lithium ion, an amount of the lithium ion being 0.1 equivalents or more and 0.95 equivalents or less, relative to 1 equivalent of the anionic group; and
a step of applying the liquid mixture onto the anode body, to form the electrolyte, wherein
the step of preparing a liquid mixture includes
a sub-step of polymerizing a precursor of the conjugated polymer in a presence of the first polymer dopant and an oxidizing agent, to obtain a first mixture containing the conjugated polymer and the first polymer dopant, and
a sub-step of further mixing the lithium ion with the first mixture, to prepare the liquid mixture as a second mixture.
10 . The method for producing an electrolytic capacitor according to claim 9 , wherein the lithium ion is mixed in a form of a salt of a second polymer dopant having an anionic group and the lithium ion, with the first mixture.
11 . The method for producing an electrolytic capacitor according to claim 9 , wherein the polymerization of the precursor is performed in an absence of the lithium ion.