WO2025183015A1 - Electrolytic capacitor - Google Patents

Abstract

An electrolytic capacitor according to the present disclosure comprises a capacitor element and a liquid component. The capacitor element comprises: an anode foil having a dielectric layer; a cathode foil disposed facing the dielectric layer; a separator interposed between the anode foil and the cathode foil; and a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator. The conductive polymer layer contains a conductive polymer. A solid-liquid electrolyte that includes the conductive polymer layer and the liquid component contains a first cationic component, a second cationic component, and an anionic component. The conductive polymer layer contains the first cationic component. The liquid component contains the second cationic component and the anionic component. In the solid-liquid electrolyte, the ratio A of the number of moles of the first cationic component, the ratio B of the number of moles of the anionic component, and the ratio C of the number of moles of the second cationic component to the mass of the conductive polymer satisfy a predetermined relationship.

Description

electrolytic capacitor

The present invention relates to an electrolytic capacitor.

An electrolytic capacitor, for example, comprises a capacitor element and an electrolyte. The capacitor element typically comprises an anode foil with a dielectric layer, a cathode foil arranged opposite the dielectric layer, and a separator interposed between the anode foil and the cathode foil. Known examples of such electrolytic capacitors include those in which the electrolyte contains a liquid component (such as an electrolytic solution) that fills the voids in the capacitor element and a conductive polymer that is interposed between the anode foil and the cathode foil. In other words, electrolytic capacitors with a solid-liquid electrolyte are known.

Patent Document 1 below describes an electrolytic capacitor comprising a capacitor element consisting of an anode foil and a cathode foil facing each other, and an electrolyte layer formed within the capacitor element, wherein the electrolyte layer comprises a solid electrolyte layer containing a dopant and a conjugated polymer, and a liquid filled in voids within the capacitor element on which the solid electrolyte layer is formed, and wherein the molar ratio of cationic components to 1 mol of functional groups that can contribute to the doping reaction of the dopant is 0.2 or more and 6 or less. Patent Document 1 below also describes that an electrolytic capacitor configured as described above is less likely to experience a sudden increase in ESR (equivalent series resistance) even after being exposed to thermal stress such as in a reflow soldering process (hereinafter also referred to as the reflow process) when mounted on a substrate or the like.

Patent No. 7196919

In recent years, there has been an increasing demand for electrolytic capacitors after the reflow process to not only prevent an increase in equivalent series resistance, but also to prevent a decrease in capacitance and an increase in leakage current.

However, in none of the publicly known documents, including the above-mentioned Patent Document 1, has sufficient research been conducted on simultaneously suppressing the decrease in capacitance, the increase in leakage current, and the increase in equivalent series resistance for electrolytic capacitors after the reflow process.

The present disclosure therefore provides an electrolytic capacitor that can simultaneously suppress capacitance reduction, leakage current increase, and equivalent series resistance increase, even after the reflow process.

One aspect of the present invention is an electrolytic capacitor comprising a capacitor element and a liquid component, wherein the capacitor element comprises an anode foil having a dielectric layer, a cathode foil arranged to face the dielectric layer, a separator interposed between the anode foil and the cathode foil, and a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator, wherein the conductive polymer layer comprises a conductive polymer, and a solid-liquid electrolyte comprising the conductive polymer layer and the liquid component comprises a first cationic component, a second cationic component, and an anionic component, and the conductive polymer layer comprises the The electrolytic capacitor comprises one cationic component, the liquid component comprising the second cationic component and the anionic component, and in the solid-liquid electrolyte, where A (mol/kg) is the ratio of the number of moles of the first cationic component to the mass of the conductive polymer, B (mol/kg) is the ratio of the number of moles of the anionic component to the mass of the conductive polymer, and C (mol/kg) is the ratio A, the ratio B, and the ratio C satisfy the relationship 0.20≦(A+C)/B≦1.01.

Another aspect of the present invention relates to an electrolytic capacitor comprising a capacitor element and a liquid component, wherein the capacitor element comprises an anode foil having a dielectric layer, a cathode foil arranged opposite the dielectric layer, a separator interposed between the anode foil and the cathode foil, and a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator, wherein the conductive polymer layer comprises a conductive polymer, and a solid-liquid electrolyte comprising the conductive polymer layer and the liquid component comprises a first cationic component and an anionic component, the conductive polymer layer comprising the first cationic component, and the liquid component comprising the anionic component, wherein, in the solid-liquid electrolyte, the ratio A (mol/kg) of the number of moles of the first cationic component to the mass of the conductive polymer is defined as A, and the ratio B (mol/kg) of the number of moles of the anionic component to the mass of the conductive polymer is defined as B, where A and B satisfy the relationship 0.20≦A/B≦1.01.

This disclosure makes it possible to provide an electrolytic capacitor that can simultaneously suppress capacitance reduction, leakage current increase, and equivalent series resistance increase, even after the reflow process.

FIG. 1 is a cross-sectional schematic view of an electrolytic capacitor according to an embodiment of the present disclosure. 2 is a schematic exploded view of a portion of a capacitor element included in the electrolytic capacitor of FIG. 1. FIG.

The following describes examples of embodiments of the present disclosure, but the present disclosure is not limited to the examples described below. In the following description, specific numerical values and materials may be used as examples, but other numerical values, materials, etc. may be applied as long as the effects of the present disclosure are obtained. Note that publicly known components may be applied to components characteristic of the present disclosure. In this specification, when a "range between numerical value A and numerical value B" is mentioned, the range includes numerical value A and numerical value B.

In the following explanation, when lower and upper limits for numerical values relating to specific physical properties or conditions are given as examples, any of the exemplified lower limits and any of the exemplified upper limits can be combined as desired, as long as the lower limit is not equal to or greater than the upper limit. When multiple materials are given as examples, one of the materials can be selected and used alone, or two or more can be used in combination, unless otherwise specified.

The present disclosure encompasses combinations of the features of two or more claims arbitrarily selected from the multiple claims set forth in the appended claims. In other words, the features of two or more claims arbitrarily selected from the multiple claims set forth in the appended claims may be combined as long as no technical contradiction arises.

[First embodiment]
The electrolytic capacitor according to the first embodiment of the present disclosure includes a capacitor element and a liquid component. In the electrolytic capacitor according to the first embodiment of the present disclosure, the capacitor element includes an anode foil having a dielectric layer, a cathode foil disposed opposite the dielectric layer, a separator interposed between the anode foil and the cathode foil, and a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator. In the electrolytic capacitor according to the first embodiment of the present disclosure, the conductive polymer layer includes a conductive polymer, and the solid-liquid electrolyte including the conductive polymer layer and the liquid component includes a first cationic component, a second cationic component, and an anionic component. In the electrolytic capacitor according to the first embodiment of the present disclosure, the conductive polymer layer includes a first cationic component, and the liquid component includes a second cationic component and an anionic component. In the electrolytic capacitor according to the first embodiment of the present disclosure, in the solid-liquid electrolyte, when the ratio of the number of moles of the first cation component to the mass of the conductive polymer is A (mol/kg), the ratio of the number of moles of the anion component to the mass of the conductive polymer is B (mol/kg), and the ratio of the number of moles of the second cation component to the mass of the conductive polymer is C (mol/kg), the ratio A, the ratio B, and the ratio C satisfy the relationship 0.20≦(A+C)/B≦1.01.

In the electrolytic capacitor according to the first embodiment of the present disclosure, when the conductive polymer layer containing the conductive polymer contains a first cationic component, the liquid component contains a second cationic component and an anionic component, and the ratio of the number of moles of the first cationic component to the mass of the conductive polymer is A (mol/kg), the ratio of the number of moles of the anionic component to the mass of the conductive polymer is B (mol/kg), and the ratio of the number of moles of the second cationic component to the mass of the conductive polymer is C (mol/kg), it is important that ratios A, B, and C satisfy the relationship 0.20≦(A+C)/B≦1.01. The reason for this is explained below.

In electrolytic capacitors, the conductive polymer layer is often formed by immersing an anode foil having a dielectric layer on at least one main surface in a polymer dispersion containing a conductive polymer. In such anode foil, at least one surface is often roughened by etching or other methods to increase capacitance. In such cases, it is preferable for the polymer dispersion to be thoroughly impregnated into the pores formed by the roughening process in order to fully extract capacitance from the interior of the pores. To fully impregnate the pores with the polymer dispersion, it is desirable for the polymer dispersion to have high wettability with at least one main surface of the anode foil. To enhance this wettability, it is desirable for the polymer dispersion to contain a cationic component. While conductive polymers are often doped with dopants, there is concern that the presence of excess cationic components may reduce the dopant's performance.

Furthermore, in a solid-liquid electrolyte containing a conductive polymer layer and a liquid component, if the amount of at least one of the first cationic component contained in the conductive polymer layer and the second cationic component contained in the liquid component is excessively small relative to the anionic component, the anionic component and the cationic component will not be sufficiently dissociated in the solid-liquid electrolyte, resulting in poor conductivity. In such a case, when exposed to thermal stress such as in a reflow process, the formation of an oxide film by the anionic component will be difficult to progress sufficiently on at least one main surface of the anode foil. In other words, the self-repairing function of the oxide film will not be fully exerted on at least one surface of the anode foil. When the self-repairing function of the oxide film is not fully exerted, leakage current will increase. Furthermore, if the solid-liquid electrolyte has poor conductivity, the equivalent series resistance of the electrolytic capacitor will decrease.

Furthermore, after an electrolytic capacitor is exposed to thermal stress, dedoping can occur in the conductive polymer, causing defects in the conductive polymer's structure. When such structural defects occur, the electrolytic capacitor's capacitance can decrease, leakage current can increase, and equivalent series resistance can rise.

However, in the electrolytic capacitor according to the first embodiment of the present disclosure, when the ratio of the number of moles of the first cationic component to the mass of the conductive polymer is A (mol/kg), the ratio of the number of moles of the anionic component to the mass of the conductive polymer is B (mol/kg), and the ratio of the number of moles of the second cationic component to the mass of the conductive polymer is C (mol/kg), the ratios A, B, and C satisfy the relationship 0.20≦(A+C)/B≦1.01. In other words, the ratios of the first cationic component and the second cationic component to the anionic component are appropriately balanced. Therefore, even when the electrolytic capacitor is subjected to thermal stress such as in a reflow process, it is believed that a decrease in capacitance, an increase in leakage current, and an increase in equivalent series resistance can be sufficiently suppressed.

In the electrolytic capacitor according to the first embodiment, it is preferable that ratios A, B, and C satisfy the relationship 0.20≦(A+C)/B<1. In other words, it is preferable that in the solid-liquid electrolyte, the sum of the number of moles of the first cationic component and the second cationic component is less than the number of moles of the anionic component. By satisfying this relationship, it is possible to further suppress undoping in the conductive polymer. This makes it possible to further suppress the occurrence of defects in the structure of the conductive polymer.

The mass of the conductive polymer can be determined, for example, according to the following procedure 1.
Step 1
(1) The anode foil, the separator, and the cathode foil are stacked in this order and wound up to obtain a first wound body, and the mass (initial mass) W0 of the first wound body is measured.
(2) The first wound body is impregnated with a first cationic component-containing polymer dispersion containing a first cationic component and a conductive polymer to obtain a second wound body, which is then dried to obtain a third wound body, and the mass W1 of the third wound body is measured.
(3) After calculating the value of W1-W0, the mass of the conductive polymer is calculated using this calculated value and the initial concentrations of the first cationic component and the conductive polymer in the first cationic component-containing polymer dispersion.

The mass of the conductive polymer can also be determined, for example, by the following procedure 2.
Step 2
(1) The capacitor element is disassembled to remove the anode foil, separator, and cathode foil.
(2) The anode foil, separator, and cathode foil are immersed in water or an organic solvent and then subjected to ultrasonic irradiation or the like to remove the conductive polymer (containing the first cationic component).
(3) After measuring the mass of the conductive polymer that has fallen off, spectra of the conductive polymer and the first cation component are obtained by Raman spectroscopy or time-of-flight secondary ion mass spectrometry (TOFSIMS), and the spectra are analyzed to determine the mass of the conductive polymer.

The number of moles of the first cationic component can be measured by NMR (Nuclear Magnetic Resonance) analysis of the main surface of the anode foil of the capacitor element taken out of the electrolytic capacitor. The NMR analysis can be performed, for example, under the following conditions.
Conditions and analysis equipment: Bruller ANACES 500
・Resonance frequency: 500MHz
Lock solvent: heavy water Measurement temperature: room temperature (23±2°C)

The number of moles of the second cation component and anion component can also be measured by NMR analysis of the liquid component collected from the electrolytic capacitor. NMR analysis of the liquid component can also be performed under the above conditions.

<Capacitor element>
As described above, the capacitor element according to the first embodiment of the present disclosure includes an anode foil having a dielectric layer, a cathode foil disposed opposite the dielectric layer, a separator interposed between the anode foil and the cathode foil, and a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator. The anode foil, cathode foil, separator, and conductive polymer layer will be described below.

(anode foil)
The anode foil may be a metal foil containing at least one valve metal such as titanium, tantalum, aluminum, or niobium. The anode foil may be a metal foil of a valve metal (e.g., aluminum foil). The anode foil may contain the valve metal in the form of an alloy containing the valve metal or a compound containing the valve metal. The thickness of the anode foil may be 15 μm or more and 300 μm or less. At least one main surface of the anode foil may be roughened by etching or the like. It is preferable that both main surfaces of the anode foil are roughened.

A dielectric layer is formed on at least one main surface of the anode foil. The dielectric layer may be formed by chemically treating the anode foil. In this case, the dielectric layer may contain an oxide of a valve metal (e.g., aluminum oxide). Note that the dielectric layer may be formed of any dielectric other than an oxide of a valve metal as long as it functions as a dielectric.

In the electrolytic capacitor according to the first embodiment of the present disclosure, a conductive polymer layer may or may not be formed on the end surface of the anode foil. However, it is preferable that a conductive polymer layer is also formed on the end surface of the anode foil. For example, in a wound capacitor element such as that shown in Figure 2, it is preferable that a dielectric layer is formed on the upper and lower end surfaces of the wound body.

(cathode foil)
The cathode foil is not particularly limited as long as it functions as a cathode. Examples of the cathode foil include metal foils (e.g., aluminum foils). The type of metal contained in the metal foil is not particularly limited. The metal may be a valve metal or an alloy containing a valve metal. The thickness of the cathode foil may be 15 μm or more and 300 μm or less. If necessary, an etching layer or a dielectric layer may be formed on at least one main surface of the cathode foil, as with the anode foil. That is, if necessary, at least one main surface of the cathode foil may be roughened or chemically treated.

The cathode foil may include a conductive coating layer. If the metal foil includes a valve metal, the coating layer may include at least one of carbon and a metal with a lower ionization tendency than the valve metal. This makes it easier to improve the acid resistance of the metal foil. If the metal foil includes aluminum, the coating layer may include at least one selected from the group consisting of carbon, nickel, titanium, tantalum, and zirconium. With an emphasis on low cost and low resistance, the coating layer may include at least one of nickel and titanium.

The thickness of the coating layer may be 5 nm or more, or 10 nm or more. The thickness of the coating layer may be 200 nm or less. The coating layer may be formed by vapor deposition or sputtering the above-mentioned metal onto the metal foil. Alternatively, the coating layer may be formed by vapor deposition of a conductive carbon material onto the metal foil, or by applying a carbon paste containing a conductive carbon material. Examples of conductive carbon materials include graphite, hard carbon, soft carbon, and carbon black.

(separator)
A porous sheet can be used for the separator. Examples of porous sheets include woven fabric, nonwoven fabric, and microporous membrane. The thickness of the separator is not particularly limited and may be in the range of 10 μm to 300 μm. Examples of separator materials include cellulose, polyethylene terephthalate, polybutylene terephthalate, polyphenyl sulfide, vinylon, nylon, aromatic polyamide, polyimide, polyamideimide, polyetherimide, rayon, and glass.

(Conductive polymer layer)
The conductive polymer layer is formed of a conductive polymer. In the electrolytic capacitor according to the first embodiment of the present disclosure, the conductive polymer layer is preferably formed of conductive polymer particles. Examples of conductive polymers include polypyrrole, polythiophene, polyaniline, and derivatives thereof. The conductive polymer may be used alone or in combination of two or more types. The conductive polymer may be a copolymer of two or more types of monomers. Note that a derivative of a conductive polymer refers to a polymer having a conductive polymer as a basic skeleton. For example, a derivative of polythiophene includes poly(3,4-ethylenedioxythiophene).

The conductive polymer may contain a dopant. The dopant can be selected appropriately depending on the type of conductive polymer. Various known dopants may be used. Examples of dopants include naphthalenesulfonic acid, p-toluenesulfonic acid, polystyrenesulfonic acid, and salts thereof. An example of a conductive polymer is poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrenesulfonic acid (PSS). In the electrolytic capacitor according to the first embodiment of the present disclosure, the conductive polymer layer is preferably formed from particles of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrenesulfonic acid (PSS) (hereinafter also referred to as PEDOT/PSS).

In the electrolytic capacitor according to the first embodiment of the present disclosure, the conductive polymer layer contains a first cationic component in addition to a conductive polymer. Examples of the first cationic component include a base component. The same cationic component as the second cationic component described below can be used as the first cationic component. In a solid-liquid electrolyte containing a conductive polymer layer and a liquid component, the first cationic component exhibits the same function as the second cationic component contained in the liquid component. That is, like the second cationic component, the first cationic component contributes to the dissociation of the anionic component and the cationic component in the solid-liquid electrolyte. Therefore, even if the liquid component does not contain the second cationic component or contains only a small amount of the second cationic component, the anionic component and the cationic component can be sufficiently dissociated in the solid-liquid electrolyte as long as the first cationic component is present in a predetermined amount or more. This allows the anionic component contained in the liquid component to fully perform its function of repairing the oxide film on the anode foil.

The valence of the first cationic component is preferably monovalent. As explained above, the first cationic component functions in a solid-liquid electrolyte in the same way as the second cationic component contained in the liquid component. That is, it functions to contribute to the dissociation state between the anionic component and the cationic component in the solid-liquid electrolyte. Therefore, by making the valence of the first cationic component monovalent, the dissociation between the anionic component and the cationic component can be more fully promoted. This allows the anionic component to more fully exert its function of repairing the oxide film on the anode foil.

The pKa of the first cationic component is preferably 10 or less. By having the pKa of the first cationic component within this range, the basicity of the first cationic component can be prevented from becoming excessively high. This further prevents the first cationic component from reducing the ability of the dopant doped into the conductive polymer.

As described above, examples of the first cationic component that is monovalent and has a pKa of 10 or less include ammonia and N-alkylmorpholine. Therefore, it is preferable to use at least one of ammonia and N-alkylmorpholine as the first cationic component. Furthermore, it is preferable to use N-methylmorpholine as the N-alkylmorpholine.

It is preferable that the conductive polymer layer be in contact with the anode foil, cathode foil, and separator over a sufficiently large contact area. This allows the conductive polymer layer to form a sufficient conductive path between the anode foil and cathode foil. As a result, the equivalent series resistance (ESR) of the electrolytic capacitor can be reduced, thereby improving the reliability of the electrolytic capacitor.

The conductive polymer layer is preferably formed on at least one selected from at least one main surface of the dielectric layer of the anode foil and at least one main surface of the cathode foil. The conductive polymer layer may also be formed within the voids of the separator (i.e., on the surface of the separator's constituent material surrounding the voids). This allows a stronger conductive path to be formed between the anode foil and the cathode foil by the conductive polymer layer. The conductive polymer layer is preferably formed on at least the surface of the dielectric layer of the anode foil, and more preferably on both the surface of the dielectric layer and the surface of the cathode foil, and furthermore, within the voids of the separator. The conductive polymer layer is preferably formed so as to continuously connect the surface of the dielectric layer and the surface of the cathode foil.

(Exterior body)
The capacitor element may be covered with an exterior body. The exterior body includes at least one of a case and a sealing resin. The case and the sealing resin are not limited, and known cases and sealing resins can be used. The sealing resin may include a thermosetting resin. Examples of thermosetting resins include epoxy resin, phenolic resin, silicone resin, melamine resin, urea resin, alkyd resin, polyurethane resin, polyimide resin, and unsaturated polyester resin. The sealing resin may include at least one selected from the group consisting of a filler, a curing agent, a polymerization initiator, and a catalyst.

<Liquid ingredients>
The liquid component includes a nonaqueous solvent and an electrolyte. The electrolyte can be a nonaqueous electrolyte containing a nonaqueous solvent and a solute dissolved in the nonaqueous solvent. The nonaqueous solvent and solute can be any of those used in various known electrolytic capacitors. The liquid component can be a component that is liquid at room temperature (25°C) or at the temperature at which the electrolytic capacitor is used.

The non-aqueous solvent may be an organic solvent or an ionic liquid.

Organic solvents include glycol compounds, sulfone compounds, and lactone compounds. Glycol compounds include ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), and propylene glycol (PG). Sulfone compounds include sulfolane (SL), dimethyl sulfoxide (DMSO), and diethyl sulfoxide (DESO). Lactone compounds include gamma-butyrolactone (GBL), gamma-valerolactone (GVL), and the like.

The organic solvent may also include carbonate compounds and monohydric, trihydric or higher alcohols. Examples of carbonate compounds include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), and fluoroethylene carbonate (FEC). Examples of monohydric, trihydric or higher alcohols include glycerin and polyglycerin. These may be used alone or in combination of two or more.

If the group of organic solvents consisting of glycol compounds, sulfone compounds, and lactone compounds is defined as Group 1, and the group of organic solvents consisting of carbonate compounds and monohydric or trihydric or higher alcohols is defined as Group 2, then organic solvents belonging to Group 1 preferably account for more than 50% by mass of the organic solvents, more preferably 60% by mass or more, and more preferably 70% by mass or more. All of the organic solvents may be organic solvents belonging to Group 1. In other words, the organic solvents belonging to Group 1 may be the main solvents, and the organic solvents belonging to Group 2 may be the secondary solvents.

The liquid component preferably contains at least one organic solvent selected from the group consisting of glycol compounds, sulfone compounds, and lactone compounds. When the liquid component contains at least one of these compounds, the dielectric layer can be efficiently reconstituted using the acid component contained in the liquid component. Furthermore, the liquid component containing a glycol compound can easily donate protons (H ⁺ ) in the glycol compound (specifically, protons (H ⁺ ) contained in hydroxyl groups) to the conductive polymer constituting the conductive polymer layer. This improves affinity with the conductive polymer layer. Furthermore, since sulfone compounds and lactone compounds are aprotic, the liquid component containing at least one of a sulfone compound and a lactone compound can prevent the liquid component from reacting with the acid component (e.g., esterification reaction). This improves the stability of the liquid component even in high-temperature environments (e.g., 145°C). This stabilizes the characteristics of the electrolytic capacitor.

When the liquid component contains at least one organic solvent selected from the group consisting of glycol compounds, sulfone compounds, and lactone compounds, the proportion of glycol compounds in the liquid component is preferably 40% by mass or more and 80% by mass or less, the proportion of sulfone compounds in the liquid component is preferably 20% by mass or more and 60% by mass or less, and the proportion of lactone compounds in the liquid component is preferably 40% by mass or more and 80% by mass or less. By containing glycol compounds, sulfone compounds, and lactone compounds in the above numerical ranges, re-chemical conversion of the dielectric layer by the acid component contained in the liquid component can be carried out more efficiently.

In order to donate protons to the conductive polymer, the liquid component may contain compounds other than glycol compounds. Examples of such compounds include glycerin and polyglycerin.

The liquid component may contain water. The water content in the liquid component may be 0.1% by mass or more and 6.0% by mass or less, 0.2% by mass or more and 4.0% by mass or less, or 0.5% by mass or more and 2.0% by mass or less. By containing water in the above range in the liquid component, the repairability of the dielectric layer by the liquid component can be improved. Furthermore, fluctuations in the equivalent series resistance (ESR) value can be suppressed when the electrolytic capacitor is used at high temperatures (for example, when used at 145°C). Furthermore, since sulfone compounds have excellent hydrolysis resistance, when the liquid component contains a sulfone compound, as described above, the hydrolysis resistance of the liquid component can be improved.

In the electrolytic capacitor according to the first embodiment of the present disclosure, the liquid component contains a second cationic component and an anionic component as solutes. Examples of the second cationic component include a base component (base), and examples of the anionic component include an acid component (acid). The second cationic component may be any of the cationic components exemplified as the first cationic component. At least a portion of the first cationic component may be the same as at least a portion of the second cationic component. The proportion of the solute in the liquid component is preferably 70% by mass or less, and more preferably 50% by mass or less.

The valence of the second cationic component is preferably monovalent. Having a monovalent second cationic component allows dissociation between the anionic component and the cationic component to proceed more fully in the solid-liquid electrolyte. This allows the anionic component to more fully perform its function of repairing the oxide film on the anode foil. When the valence of the second cationic component is monovalent, it is preferable that the valence of the first cationic component is also monovalent. This allows dissociation between the anionic component and the cationic component to proceed more fully in the solid-liquid electrolyte. This allows the anionic component to more fully perform its function of repairing the oxide film on the anode foil.

The acid component includes at least one selected from the group consisting of aromatic carboxylic acids, aliphatic carboxylic acids, and salts thereof. The aromatic carboxylic acids and aliphatic carboxylic acids may be polycarboxylic acids or monocarboxylic acids. Aliphatic polycarboxylic acids include saturated polycarboxylic acids and unsaturated polycarboxylic acids. Saturated polycarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,6-decanedicarboxylic acid, and 5,6-decanecarboxylic acid. Unsaturated polycarboxylic acids include maleic acid, fumaric acid, and itaconic acid. Aromatic polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, and benzoic acid. The phthalic acid may be o-phthalic acid. An aromatic monocarboxylic acid includes salicylic acid.

Polycarboxylic acids also include alicyclic polycarboxylic acids. Examples of alicyclic polycarboxylic acids include cyclohexane-1,2-dicarboxylic acid and cyclohexene-1,2-dicarboxylic acid.

Examples of monocarboxylic acids include aliphatic monocarboxylic acids and aromatic monocarboxylic acids. In this specification, aromatic monocarboxylic acids are used to encompass hydroxycarboxylic acids. Examples of aliphatic monocarboxylic acids include saturated monocarboxylic acids and unsaturated monocarboxylic acids. Examples of saturated monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid, stearic acid, and behenic acid. Examples of unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, and oleic acid. Examples of aromatic monocarboxylic acids include benzoic acid, cinnamic acid, and naphthoic acid. Examples of hydroxycarboxylic acids include salicylic acid, mandelic acid, and resorcylic acid.

As the aromatic carboxylic acid, it is preferable to use at least one selected from the group consisting of o-phthalic acid, salicylic acid, and benzoic acid. As the aliphatic carboxylic acid, it is preferable to use at least one selected from the group consisting of adipic acid, azelaic acid, and sebacic acid.

An inorganic acid may be used as the acid component. Examples of inorganic acids include phosphoric acid, phosphorous acid, hypophosphorous acid, alkyl phosphate esters, boric acid, fluoroboric acid, tetrafluoroboric acid, hexafluorophosphoric acid, benzenesulfonic acid, and naphthalenesulfonic acid. Furthermore, a composite compound of an organic acid and an inorganic acid may be used as the acid component. Examples of such composite compounds include dicarboxylic acid derivatives such as borodiglycolic acid, borodisalic acid, and borodisalicylic acid.

The base component may be a compound having an alkyl-substituted amidine group, such as an imidazole compound, a benzimidazole compound, or an alicyclic amidine compound (pyrimidine compound, imidazoline compound). Specifically, 1,8-diazabicyclo[5,4,0]undecene-7; 1,5-diazabicyclo[4,3,0]nonene-5; 1,2-dimethylimidazolinium; 1,2,4-trimethylimidazoline; 1-methyl-2-ethylimidazoline; 1,4-dimethyl-2-ethylimidazoline; 1-methyl-2-heptylimidazoline; 1-methyl-2-(3'heptyl)imidazoline; 1-methyl-2-dodecylimidazoline; 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine; 1-methylimidazole; and 1-methylbenzimidazole are preferred. By using these, electrolytic capacitors can be made to have excellent impedance characteristics.

A quaternary salt of a compound having an alkyl-substituted amidine group may also be used as the base component. Examples of such base components include imidazole compounds, benzimidazole compounds, and alicyclic amidine compounds (pyrimidine compounds, imidazoline compounds) quaternized with an alkyl or arylalkyl group having 1 to 11 carbon atoms. Specifically, 1-methyl-1,8-diazabicyclo[5,4,0]undecene-7; 1-methyl-1,5-diazabicyclo[4,3,0]nonene-5; 1,2,3-trimethylimidazolinium; 1,2,3,4-tetramethylimidazolinium; 1,2-dimethyl-3-ethyl-imidazolinium; 1,3,4-trimethyl-2-ethylimidazolinium; 1,3-dimethyl-2-heptylimidazolinium; 1,3-dimethyl-2-(3'heptyl)imidazolinium; 1,3-dimethyl-2-dodecylimidazolinium; 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidium; 1,3-dimethylimidazolium; 1-methyl-3-ethylimidazolium; 1,3-dimethylbenzimidazolium is preferred. Using these materials can also give electrolytic capacitors excellent impedance characteristics.

A tertiary amine may be used as the base component. Examples of tertiary amines include trialkylamines and phenyl-containing amines. Examples of trialkylamines include trimethylamine, dimethylethylamine, methyldiethylamine, triethylamine, dimethyl-n-propylamine, dimethylisopropylamine, methylethyl-n-propylamine, methylethylisopropylamine, diethyl-n-propylamine, diethylisopropylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, and tri-tert-butylamine. Examples of phenyl-containing amines include dimethylphenylamine, methylethylphenylamine, and diethylphenylamine. From the perspective of increasing conductivity, trialkylamines are preferred, and among trialkylamines, it is preferable to use at least one selected from the group consisting of trimethylamine, dimethylethylamine, methyldiethylamine, and triethylamine. Examples of the base component may include secondary amines such as dialkylamines, primary amines such as monoalkylamines, and ammonia.

Heterocyclic amines may be used as the base component. Examples of heterocyclic amines include morpholines, such as morpholine and morpholine derivatives. Specific examples include morpholine, N-alkyl morpholine, and N-hydroxyalkyl morpholine. Examples of N-alkyl morpholines include N-methyl morpholine, N-butyl morpholine, and 4-isobutyl morpholine. Pyridine and imidazole may also be used as heterocyclic amines.

The pKa of the second cationic component, such as a base component, is preferably 11 or less. Examples of second cationic components with a pKa of 11 or less include triethylamine, dimethylethylamine, morpholine, and ammonia. In other words, it is preferable to use at least one selected from the group consisting of triethylamine, dimethylethylamine, morpholine, and ammonia as the second cationic component. By ensuring that the pKa of the second cationic component is 11 or less, the basicity of the second cationic component can be prevented from becoming excessively high. This further prevents the second cationic component from reducing the performance of the dopant doped into the conductive polymer. As a result, various properties of the electrolytic capacitor can be further improved. For example, in an electrolytic capacitor, a decrease in capacitance can be further suppressed, and an increase in equivalent series resistance can be further suppressed.

The liquid component may contain a salt of an acid component and a base component. The salt may be an inorganic salt or an organic salt. An organic salt is a salt in which at least one of the anion and cation contains an organic substance. Examples of organic salts include trimethylamine maleate, triethylamine borodisalicylate, ethyldimethylamine phthalate, mono 1,2,3,4-tetramethylimidazolinium phthalate, and mono 1,3-dimethyl-2-ethylimidazolinium phthalate. The organic salt may also be an amine salt of a long-chain dibasic carboxylic acid. An example of an amine salt of a long-chain dibasic carboxylic acid is diethylamine 2-butyloctanedioate (2BA).

Ionic liquid is synonymous with molten salt (molten salt), and is, for example, an ionic substance that is liquid at 25°C.

Cations that make up ionic liquids include, for example, cations of nitrogen-containing heterocycles (imidazolium, pyrrolidinium, piperidinium, pyridinium, morpholinium, etc.), ammonium, phosphonium, sulfonium, and derivatives thereof (e.g., substituted compounds having a substituent such as an alkyl group). The cation may also be an organic cation.

Examples of anions that constitute ionic liquids include hydrogen sulfate ion (HSO ₄ ⁻ ), sulfate ion (SO ₄ ²⁻ , —SO ₄ ⁻ ), carboxylate anion (—COO ⁻ ), nitrate anion, sulfonate anion (—SO ₃ ⁻ ), and phosphonate anion (PO ₃ ²⁻ , —HPO ₃ ⁻ ). Acids that can generate these anions include sulfuric acid, sulfate monoesters (methyl sulfate, etc.), carboxylic acids (acetic acid, lactic acid, benzoic acid, trifluoromethaneacetic acid, etc.), nitric acid, sulfonic acids (methanesulfonic acid, trifluoromethanesulfonic acid, bis(trifluoromethylsulfonyl)imide anion, etc.), phosphonic acids (diethylphosphonic acid, etc.), and derivatives thereof (e.g., substituted derivatives having a substituent such as an alkyl group, an alkyl halide, or a halogen atom). The anion may contain a fluorine atom. Examples of fluorine atom-containing anions include the above-mentioned trifluoromethaneacetic acid, trifluoromethanesulfonic acid, bis(trifluoromethylsulfonyl)imide anions, and derivatives thereof.

Specific examples of ionic liquids include 1-butyl-3-methylimidazolium hydrogen sulfate, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, and 1-ethyl-3-methylimidazolium diethylphosphonate.

The liquid component may contain a polymeric compound. Examples of polymeric compounds include polyalkylene glycols, polyalkylene glycol derivatives, and compounds in which at least one hydroxyl group of a polyhydric alcohol has been substituted with polyalkylene glycol (including derivatives). Specific examples include polyethylene glycol (PEG), polyethylene glycol glyceryl ether, polyethylene glycol diglyceryl ether, polyethylene glycol sorbitol ether, polypropylene glycol, polypropylene glycol diglyceryl ether, polypropylene glycol sorbitol ether, and polybutylene glycol.

The polyalkylene glycol may be a copolymer (random copolymer, block copolymer, random block copolymer, etc.). For example, it may be a copolymer of ethylene glycol and propylene glycol, a copolymer of ethylene glycol and butylene glycol, or a copolymer of propylene glycol and butylene glycol.

The polymer compound may be a copolymer having ethylene oxide (EO) units and propylene oxide (PO) units. The copolymer includes a copolymer of EO and PO (EO-PO copolymer) and derivatives thereof. These may be used alone or in combination of two or more. The copolymer may be crosslinked with a crosslinking agent. Examples of the derivative include an EO-PO copolymer in which the hydroxyl group (—OH) normally present at the terminal is substituted with an acrylic group (O—CO—CH═CH ₂ ). The molar ratio of EO units to PO units, based on 1 mole of the entire EO-PO copolymer, is preferably 0.9:0.1 to 0.5:0.5. In other words, the EO-PO copolymer preferably contains at least the same amount of EO units as the PO units. This makes it possible to prevent the EO-PO copolymer contained in the liquid component from permeating through the sealing member in an electrolytic capacitor in which a capacitor element is housed in a bottomed case and the opening of the bottomed case is sealed with a sealing member (such as sealing rubber).

In the electrolytic capacitor according to the embodiment of the present disclosure, the mass average molecular weight Mw of the polymer compound may be 200 or more, 300 or more, 400 or more, or 500 or more. The mass average molecular weight Mw of the polymer compound may be 5000 or less, 4000 or less, 3000 or less, 2000 or less, or 1000 or less.

The mass average molecular weight Mw of a polymer compound is a polystyrene-equivalent value measured by gel permeation chromatography (GPC). GPC measurements are typically performed using a polystyrene gel column and water/methanol (volume ratio 8/2) as the mobile phase.

Measurement by GPC can be performed, for example, using a column consisting of two connected Shodex OHpak SB804HQ and SB8025HQ columns, using a ₅₀ mM aqueous NaNO3 solution as an eluent, using an RI detector, setting the column temperature to 40°C, the flow rate of the eluent to 0.7 mL/min, and the analysis time to 40 min.

[Second embodiment]
An electrolytic capacitor according to a second embodiment of the present disclosure includes a capacitor element and a liquid component. In the electrolytic capacitor according to the second embodiment of the present disclosure, the capacitor element includes an anode foil having a dielectric layer, a cathode foil disposed opposite the dielectric layer, a separator interposed between the anode foil and the cathode foil, and a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator. In the electrolytic capacitor according to the second embodiment of the present disclosure, the conductive polymer layer includes a conductive polymer, and the solid-liquid electrolyte including the conductive polymer layer and the liquid component includes a first cation component and an anion component. In the electrolytic capacitor according to the second embodiment of the present disclosure, the conductive polymer layer includes the first cation component, and the liquid component includes an anion component. In the electrolytic capacitor according to the second embodiment of the present disclosure, in the solid-liquid electrolyte, when the ratio of the number of moles of the first cation component to the mass of the conductive polymer is A (mol/kg) and the ratio of the number of moles of the anion component to the mass of the conductive polymer is B (mol/kg), the ratio A and the ratio B satisfy the relationship 0.20≦A/B≦1.01.

As described above, the electrolytic capacitor according to the first embodiment and the electrolytic capacitor according to the second embodiment differ primarily in that, in the electrolytic capacitor according to the first embodiment, the solid-liquid electrolyte contains three ionic components: a first cation component, a second cation component, and an anion component, whereas, in the electrolytic capacitor according to the second embodiment, the solid-liquid electrolyte contains two ionic components: a first cation component and an anion component.

Even if the liquid component does not contain the second cationic component, if the ratio A (mol/kg) of the number of moles of the first cationic component to the mass of the conductive polymer and the ratio B (mol/kg) of the number of moles of the anionic component to the mass of the conductive polymer in the solid-liquid electrolyte satisfy the appropriate relationship described above, the electrolytic capacitor according to the second embodiment, like the electrolytic capacitor according to the first embodiment, can simultaneously suppress a decrease in capacitance, an increase in leakage current, and an increase in equivalent series resistance, even after the reflow process.

In the electrolytic capacitor according to the second embodiment, it is preferable that ratio A and ratio B satisfy the relationship 0.20≦A/B<1. In other words, it is preferable that the number of moles of the first cation component is smaller than the number of moles of the anion component in the solid-liquid electrolyte. By satisfying this relationship, it is possible to further suppress the occurrence of undoping in the conductive polymer. This makes it possible to further suppress the occurrence of defects in the structure of the conductive polymer.

The specific configuration of an electrolytic capacitor according to one embodiment of the present disclosure will now be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view showing a schematic diagram of an electrolytic capacitor 100 according to one embodiment of the present disclosure, and Figure 2 is a schematic diagram showing a portion of a capacitor element 10 included in the electrolytic capacitor 100.

The electrolytic capacitor 100 comprises a capacitor element 10, a bottomed case 101 that houses the capacitor element 10, a sealing member 102 (e.g., a rubber seal) that closes the opening of the bottomed case 101, a seat plate 103 that covers the sealing member 102, the seat plate 103 that is arranged on the outside of the bottomed case 101 so as to cover the sealing member 102 from the opening side of the bottomed case 101, a pair of lead wires 104A, 104B that extend from the sealing member 102 and pass through the seat plate 103, and a pair of lead tabs 105A, 105B that connect each of the pair of lead wires 104A, 104B to electrodes of the capacitor element (e.g., an anode foil 11 and a cathode foil 12, described below). The bottomed case 101 is drawn near its open end to create an inward recess, and the open end of the bottomed case 101 is curled to fit onto the sealing member 102. In the example shown in Figure 1, lead wire 104A is connected to the electrode of the capacitor element via lead tab 105A, and lead wire 104B is connected to the electrode of the capacitor element via lead tab 105B.

The sealing member 102 is formed from an elastic material containing a rubber component. Examples of rubber components that can be used include butyl rubber (IIR), nitrile rubber (NBR), ethylene propylene rubber, ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), isoprene rubber (IR), Hypalon (trademark) rubber, silicone rubber, and fluororubber. The sealing member 102 may also contain fillers such as carbon black and silica.

Capacitor element 10 is configured, for example, as a wound body as shown in Figure 2. The wound body includes anode foil 11 connected to lead tab 105A, cathode foil 12 connected to lead tab 105B, and separator 13. Capacitor element 10 includes a conductive polymer layer (not shown). Note that electrolytic capacitor 100 shown in Figure 1 includes capacitor element 10 shown in Figure 2, and is therefore referred to as a wound-type electrolytic capacitor.

The anode foil 11 and cathode foil 12 are wound with a separator 13 interposed between them to form a wound body. The outermost periphery of this wound body is secured with a stop tape 14. Note that Figure 2 shows the wound body in a partially unfolded state before the outermost periphery is secured with the stop tape 14.

The electrolytic capacitor according to the present disclosure may have at least one capacitor element, or may have multiple capacitor elements. The number of capacitor elements included in the electrolytic capacitor is determined appropriately depending on the application.

Although Figures 1 and 2 illustrate a wound-type electrolytic capacitor, the electrolytic capacitor according to the embodiment of the present disclosure is not limited to this and may be a chip-type electrolytic capacitor or a stacked-type electrolytic capacitor.

[Manufacturing method of electrolytic capacitors]
An example of a method for manufacturing an electrolytic capacitor according to an embodiment of the present disclosure includes the steps of: (a) preparing an anode foil, a cathode foil, and a separator each having a dielectric layer; (b) applying a polymer dispersion containing a conductive polymer and a dopant dispersed in a liquid medium to the surface of the dielectric layer, at least one main surface of the cathode foil, and voids in the separator, the polymer dispersion including a first cationic component (hereinafter also referred to as a first cationic component-containing polymer dispersion); (c) forming a conductive polymer layer on the one main surface and in the voids in the separator by removing at least a portion of the liquid medium from the first cationic component-containing polymer dispersion; (d) forming a capacitor element by disposing a separator between the anode foil and the cathode foil; and (e) filling the voids in the capacitor element with a liquid component including a second cationic component and an anionic component. In the method for manufacturing an electrolytic capacitor according to an embodiment of the present disclosure, the steps (a) to (e) are preferably performed in this order.

<(a) Process>
The process for preparing the anode foil, cathode foil, and separator having a dielectric layer is not particularly limited. The materials for the anode foil, cathode foil, and separator are also not particularly limited. For example, the above-described materials can be used as the anode foil, cathode foil, and separator.

<(b) Process>
In step (b), the first cationic component-containing polymer dispersion may be applied to the surface of the dielectric layer and the separator, or to at least one main surface of the cathode foil and the separator. Alternatively, the first cationic component-containing polymer dispersion may be applied to the surface of the dielectric layer, at least one main surface of the cathode foil, and the separator. When dielectric layers are formed on both main surfaces of the anode foil, the first cationic component-containing polymer dispersion may be applied to the surfaces of the dielectric layers formed on both main surfaces of the anode foil. The first cationic component-containing polymer dispersion may also be applied to both main surfaces of the cathode foil. A conductive polymer layer is formed at the location where the first cationic component-containing polymer dispersion is applied. The first cationic component may be any of those described above.

Examples of methods for applying the first cationic component-containing polymer dispersion include coating. Coating can be carried out by various known methods. Examples of coating include coating using a coater, spray coating, and coating by immersing the object to be coated in the first cationic component-containing polymer dispersion. Examples of coating using a coater include gravure coating and die coating. Note that the liquid medium can be, for example, water.

<(c) Process>
In step (c), the method for removing at least a portion of the liquid medium from the first cation component-containing polymer dispersion is not particularly limited. The liquid medium is preferably removed by at least heating. The liquid medium may be removed by heating under reduced pressure. When the liquid medium is water, the liquid medium is preferably removed by heating the liquid medium to 100°C or higher.

If the electrolytic capacitor is a wound-type electrolytic capacitor 100 as shown in Figure 1, the conductive polymer layer can be formed by impregnating a capacitor element 10 configured as a wound body as shown in Figure 2 with a polymer dispersion containing a first cation component, and then heating the capacitor element 10 at a predetermined temperature.

<(d) Process>
In step (d), a conductive polymer layer is formed on the surface of the dielectric layer, on at least one main surface of the cathode foil, and on a separator, and then the separator is disposed between the anode foil and the cathode foil to form a capacitor element (specifically, a capacitor element including a conductive polymer layer). This step is also a step in which the anode foil and the cathode foil are laminated with the separator interposed therebetween.

The method for forming the capacitor element is not particularly limited. The capacitor element may be formed by any known method. The capacitor element may be a wound body as shown in Figure 2. In the wound body as shown in Figure 2, the anode foil, cathode foil, and separator are stacked in the radial direction of the wound body.

A capacitor element may be formed by stacking flat anode foils, flat cathode foils, and flat separators in one direction. For example, a capacitor element may be formed by stacking multiple anode foils, multiple cathode foils, and multiple separators in one direction. An electrolytic capacitor including such a stacked capacitor element is called a stacked electrolytic capacitor. In a typical example of a stack, the anode foils and cathode foils are arranged alternately, and a separator is placed between the anode foils and cathode foils.

<(e) Process>
The method for filling the voids in the capacitor element with the liquid component is not particularly limited. For example, the voids in the capacitor element may be filled with the liquid component by impregnating at least a portion of the capacitor element with a liquid component containing the second cationic component and the anionic component. Note that the second cationic component and the anionic component may be those described above.

By carrying out steps (a) through (e) as described above, a capacitor element is formed having a conductive polymer layer containing a first cationic component and a liquid component containing a second cationic component and an anionic component. The capacitor element is then encapsulated in an exterior body (case) as needed. In this manner, an electrolytic capacitor according to an embodiment of the present disclosure is manufactured.

In the above, an example was described in which a conductive polymer layer is formed on the surface of the dielectric layer and at least one main surface of the cathode foil, and on the separator before the anode foil and cathode foil are laminated together with the separator interposed therebetween. However, the example of forming a conductive polymer layer is not limited to this. The conductive polymer layer may also be formed after the anode foil and cathode foil are laminated together with the separator interposed therebetween. For example, after obtaining a wound body in which the anode foil and cathode foil are laminated together with the separator interposed therebetween, the wound body may be immersed in a polymer dispersion containing a first cation component, thereby forming a conductive polymer layer on the surface of the dielectric layer and at least one main surface of the cathode foil, and on the separator.

(Additional Note)
The above description discloses the following techniques.
(Technology 1)
An electrolytic capacitor comprising a capacitor element and a liquid component,
The capacitor element is
an anode foil having a dielectric layer;
a cathode foil disposed so as to face the dielectric layer;
a separator interposed between the anode foil and the cathode foil;
a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator,
the conductive polymer layer includes a conductive polymer,
the solid-liquid electrolyte containing the conductive polymer layer and the liquid component contains a first cationic component, a second cationic component, and an anionic component;
the conductive polymer layer contains the first cationic component,
the liquid component includes the second cationic component and the anionic component,
In the solid-liquid electrolyte, when the ratio of the number of moles of the first cation component to the mass of the conductive polymer is A (mol/kg), the ratio of the number of moles of the anion component to the mass of the conductive polymer is B (mol/kg), and the ratio of the number of moles of the second cation component to the mass of the conductive polymer is C (mol/kg),
the ratio A, the ratio B, and the ratio C satisfy the relationship 0.20≦(A+C)/B≦1.01,
Electrolytic capacitor.
(Technology 2)
An electrolytic capacitor comprising a capacitor element and a liquid component,
The capacitor element is
an anode foil having a dielectric layer;
a cathode foil disposed so as to face the dielectric layer;
a separator interposed between the anode foil and the cathode foil;
a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator,
the conductive polymer layer includes a conductive polymer,
the solid-liquid electrolyte containing the conductive polymer layer and the liquid component contains a first cation component and an anion component;
the conductive polymer layer contains the first cationic component,
the liquid component includes the anion component,
In the solid-liquid electrolyte, when the ratio of the number of moles of the first cation component to the mass of the conductive polymer is A (mol/kg) and the ratio of the number of moles of the anion component to the mass of the conductive polymer is B (mol/kg),
the ratio A and the ratio B satisfy the relationship 0.20≦A/B≦1.01,
Electrolytic capacitor.
(Technology 3)
the ratio A, the ratio B, and the ratio C satisfy the relationship 0.20≦(A+C)/B<1,
The electrolytic capacitor according to the first aspect of the present invention.
(Technology 4)
The ratio A and the ratio B satisfy the relationship of 0.20≦A/B<1.
The electrolytic capacitor according to the second aspect of the present invention.
(Technique 5)
The ratio A is in the range of 1 mol/kg or more and 30 mol/kg or more, the ratio B is in the range of 25 mol/kg or more and 45 mol/kg or more, and the ratio C is in the range of 1 mol/kg to 25 mol/kg or more.
The electrolytic capacitor according to any one of claims 1 to 3.
(Technology 6)
the valence of the first cationic component and the second cationic component is both 1;
6. The electrolytic capacitor according to claim 1, 3, or 5.
(Technology 7)
The pKa of the first cationic component is 10 or less.
7. The electrolytic capacitor according to any one of the first to sixth aspects.
(Technology 8)
the pKa of the second cationic component is 11 or less;
The electrolytic capacitor according to any one of claims 1 to 7.
(Technology 9)
The anion component is at least one selected from the group consisting of aromatic carboxylic acids, aliphatic carboxylic acids, and salts thereof.
The electrolytic capacitor according to any one of the first to eighth aspects.
(Technology 10)
The aromatic carboxylic acid is at least one selected from the group consisting of o-phthalic acid, salicylic acid, and benzoic acid.
The electrolytic capacitor according to claim 9.
(Technology 11)
The aliphatic carboxylic acid is at least one selected from the group consisting of adipic acid, azelaic acid, and sebacic acid.
The electrolytic capacitor according to claim 9.

Although the present invention has been described with reference to the presently preferred embodiments, such disclosure should not be interpreted as limiting. Various modifications and alterations will no doubt become apparent to those skilled in the art to which the present invention pertains upon reading the above disclosure. Accordingly, the appended claims should be interpreted to cover all modifications and alterations without departing from the true spirit and scope of the invention.

The present disclosure will be specifically explained below based on examples and comparative examples, but the present disclosure is not limited to the following examples.

[Example 1]
(A) Preparation of Components (A-1) Anode Foil Both main surfaces of an aluminum foil (thickness 100 μm) were etched to obtain an aluminum foil with roughened main surfaces. After etching, both main surfaces of the aluminum foil were subjected to a chemical conversion treatment to form a dielectric layer on both main surfaces. In this way, an anode foil with a dielectric layer formed on both main surfaces was obtained.

(A-2) Cathode Foil Both main surfaces of an aluminum foil (thickness 50 μm) were subjected to an etching treatment to obtain a cathode foil with both main surfaces roughened.

(A-3) Separator A nonwoven fabric (50 μm thick) was prepared as a separator. The nonwoven fabric was composed of 50% by mass of synthetic fibers (25% by mass of polyester fibers and 25% by mass of aramid fibers) and 50% by mass of cellulose, and contained polyacrylamide as a paper strength agent. The density of the nonwoven fabric was 0.35 g/ ^cm3 .

(B) Preparation of First Cationic Component-Containing Polymer Dispersion 3,4-ethylenedioxythiophene and poly(4-styrenesulfonic acid) (PSS, mass-average molecular weight Mw 100,000; dopant) were dissolved in ion-exchanged water to prepare a mixed solution. Next, while stirring this mixed solution, an oxidizing agent (iron(III) sulfate and ammonium persulfate) dissolved in ion-exchanged water was added to the mixed solution to carry out a polymerization reaction. After the polymerization reaction, the resulting reaction solution was dialyzed to remove unreacted monomer and excess oxidizing agent. This resulted in a polymer dispersion doped with PSS (PEDOT/PSS). Next, 0.0044 mmol (1.47 mol per kg of PEDOT/PSS) of ammonia was added to this polymer dispersion as the first cationic component to obtain a first cationic component-containing polymer dispersion.

(C) Fabrication of a Wound Body The anode foil, cathode foil, and separator were each cut to have predetermined planar dimensions. An anode lead tab was connected to the anode foil, and a cathode lead tab was connected to the cathode foil. Next, the anode foil and cathode foil were wound with the separator interposed therebetween to obtain a wound body. At this time, the ends of the outer surface of the wound body were fixed with winding tape. An anode lead wire was connected to the end of the anode lead tab, and a cathode lead wire was connected to the end of the cathode lead tab. The wound body obtained as described above was again subjected to chemical conversion treatment to form a dielectric layer on the end surface of the anode foil. Specifically, dielectric layers were formed on the upper and lower end surfaces of the wound body as shown in FIG. 2.

(D) Formation of Conductive Polymer Layer The wound body was immersed in a first cationic component-containing polymer dispersion contained in a designated container in a reduced pressure atmosphere (40 kPa) for 5 minutes. The first cationic component-containing polymer dispersion was almost entirely (98% by volume or more) impregnated into the wound body. The wound body impregnated with the first cationic component-containing polymer dispersion was then dried in a drying oven at 150°C for 20 minutes to form a conductive polymer layer covering at least a portion of the dielectric layer. In other words, a wound body containing a conductive polymer layer (hereinafter also referred to as a wound body containing a conductive polymer layer) was obtained.

(E) Impregnation with Liquid Component A mixed solvent containing polyethylene glycol (PEG), ethylene glycol (EG), and sulfolane (SL) was prepared. The volume ratio of PEG, EG, and SL in this mixed solvent was PEG:EG:SL = 30:20:50. Phthalic acid (FT) as the anion component and dimethylethylamine (DEA) as the second cation component were added to this mixed solvent in the amounts shown in Table 1A below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 29.68 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 23.74 mol per kg of PEDOT/PSS. Next, the wound body containing the conductive polymer layer was immersed in this electrolyte solution for 5 minutes. Note that the wound body containing the conductive polymer layer was almost entirely (98% by volume or more) immersed in the electrolyte solution. As a result, a capacitor element according to Example 1 was obtained. Furthermore, when the ratio of the number of moles of the first cation component to the mass of the conductive polymer was A (mol/kg), the ratio of the number of moles of the anion component to the mass of the conductive polymer was B (mol/kg), and the ratio of the number of moles of the second cation component to the mass of the conductive polymer was C (mol/kg), (A+C)/B was 0.85.

The capacitor element of Example 1 was sealed to produce an electrolytic capacitor as shown in Figure 1. An aging treatment was then performed at 95°C for 90 minutes while a voltage was applied. In this way, the electrolytic capacitor of Example 1 was obtained. Note that an elastic member containing butyl rubber as the rubber component was used as the sealing member for sealing the capacitor element. Note that 60 electrolytic capacitors were produced. The same applies to each of the following examples.

[Example 2]
The electrolytic capacitor of Example 2 was obtained in the same manner as Example 1, except that an electrolyte solution (liquid component) was prepared by adding phthalic acid (FT) as the anion component and dimethylethylamine (DEA) as the second cation component to the mixed solvent in the molar ratios shown in Table 1A below. Specifically, phthalic acid (FT) was added in an amount of 32.89 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 16.44 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 2, (A + C)/B was 0.54.

[Example 3]
The electrolytic capacitor of Example 3 was obtained in the same manner as in Example 1, except that 0.0132 mmol (4.41 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component when obtaining the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Example 3, (A+C)/B was 0.95.

[Example 4]
The electrolytic capacitor of Example 4 was obtained in the same manner as in Example 2, except that 0.0132 mmol (4.41 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component to obtain the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Example 4, (A+C)/B was 0.63.

[Example 5]
The electrolytic capacitor of Example 5 was obtained in the same manner as Example 1, except that phthalic acid (FT) as the anion component and dimethylethylamine (DEA) as the second cation component were added to the mixed solvent in the amounts shown in Table 1A below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 38.43 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 3.84 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 5, (A + C)/B was 0.21.

[Example 6]
The electrolytic capacitor of Example 6 was obtained in the same manner as in Example 2, except that 0.0229 mmol of ammonia (7.65 mol per kg of PEDOT/PSS) was used as the first cationic component when obtaining the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Example 6, (A+C)/B was 0.73.

[Example 7]
The electrolytic capacitor of Example 7 was obtained in the same manner as in Example 5, except that 0.0229 mmol of ammonia (7.65 mol per kg of PEDOT/PSS) was used as the first cationic component to obtain the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Example 7, (A+C)/B was 0.30.

[Example 8]
The electrolytic capacitor of Example 8 was obtained in the same manner as in Example 2, except that 0.0441 mmol (14.71 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component when obtaining the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Example 8, (A+C)/B was 0.95.

[Example 9]
The electrolytic capacitor of Example 9 was obtained in the same manner as in Example 5, except that 0.0441 mmol (14.71 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component to obtain the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Example 9, (A+C)/B was 0.48.

[Example 10]
The electrolytic capacitor of Example 10 was obtained in the same manner as in Example 8, except that the electrolyte solution (liquid component) contained only phthalic acid (FT) as the anion component in the molar ratio shown in Table 1A below. Specifically, the electrolyte solution (liquid component) contained 40.13 mol of phthalic acid (FT) per kg of PEDOT/PSS. In addition, the A/B ratio for the electrolytic capacitor of Example 10 was 0.37.

[Example 11]
The electrolytic capacitor of Example 11 was obtained in the same manner as in Example 5, except that 0.0882 mmol (29.41 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component when obtaining the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Example 11, (A+C)/B was 0.87.

[Example 12]
The electrolytic capacitor of Example 12 was obtained in the same manner as in Example 11, except that the electrolyte solution (liquid component) contained only phthalic acid (FT) as the anion component in the molar ratio shown in Table 1A below. Specifically, the electrolyte solution (liquid component) contained 40.13 mol of phthalic acid (FT) per kg of PEDOT/PSS. In addition, the A/B ratio for the electrolytic capacitor of Example 12 was 0.73.

[Example 13]
The electrolytic capacitor of Example 13 was obtained in the same manner as in Example 8, except that triethylamine (TEA) was used as the second cationic component, and phthalic acid (FT) and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1A below to prepare the electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 30.76 mol per kg of PEDOT/PSS, and triethylamine (TEA) was added in an amount of 15.38 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 13, (A + C)/B was 0.98.

[Example 14]
The electrolytic capacitor of Example 14 was obtained in the same manner as in Example 13, except that phthalic acid (FT) and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1A below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 37.82 mol per kg of PEDOT/PSS, and triethylamine (TEA) was added in an amount of 3.78 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 14, (A + C)/B was 0.49.

[Example 15]
The electrolytic capacitor of Example 15 was obtained in the same manner as in Example 13, except that 1,2,3,4-tetramethylimidazolinium (TMI) was used as the second cation component, and phthalic acid (FT) and 1,2,3,4-tetramethylimidazolinium (TMI) were added to the mixed solvent in the amounts shown in Table 1A below to prepare the electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 29.02 mol per kg of PEDOT/PSS, and 1,2,3,4-tetramethylimidazolinium (TMI) was added in an amount of 14.51 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 15, (A + C)/B was 1.01.

[Example 16]
The electrolytic capacitor of Example 16 was obtained in the same manner as Example 15, except that phthalic acid (FT) and 1,2,3,4-tetramethylimidazolinium (TMI) were added to the mixed solvent in the amounts shown in Table 1A below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 37.27 mol per kg of PEDOT/PSS, and 1,2,3,4-tetramethylimidazolinium (TMI) was added in an amount of 3.73 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 16, (A+C)/B was 0.49.

[Example 17]
The electrolytic capacitor of Example 17 was obtained in the same manner as in Example 2, except that 0.0445 mmol (14.83 mol per kg of PEDOT/PSS) of methylmorpholine (MHP) was used as the first cationic component when obtaining the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Example 17, (A+C)/B was 0.95.

[Example 18]
The electrolytic capacitor of Example 18 was obtained in the same manner as in Example 17, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1A below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 38.43 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 3.84 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 18, (A + C)/B was 0.49.

[Example 19]
The electrolytic capacitor of Example 19 was obtained in the same manner as in Example 17, except that the electrolyte solution (liquid component) contained only phthalic acid (FT) as the anion component in the amount shown in Table 1A below. Specifically, the electrolyte solution (liquid component) contained 40.13 mol of phthalic acid (FT) per kg of PEDOT/PSS. In addition, the A/B ratio for the electrolytic capacitor of Example 19 was 0.37.

[Example 20]
The electrolytic capacitor of Example 20 was obtained in the same manner as in Example 8, except that methylmorpholine (MHP) was used as the second cation component, and phthalic acid (FT) and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1A below to prepare the electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 30.76 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 15.38 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 20, (A + C)/B was 0.98.

[Example 21]
The electrolytic capacitor of Example 21 was obtained in the same manner as in Example 20, except that phthalic acid (FT) and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1A below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 37.82 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 3.78 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 21, (A + C)/B was 0.49.

[Example 22]
The electrolytic capacitor of Example 22 was obtained in the same manner as in Example 13, except that azelaic acid was used as the anion component, and azelaic acid and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1A below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 33.61 mol per kg of PEDOT/PSS, and triethylamine (TEA) was added in an amount of 3.36 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 22, (A + C)/B was 0.54.

[Example 23]
The electrolytic capacitor of Example 23 was obtained in the same manner as in Example 22, except that the electrolyte (liquid component) contained only azelaic acid as the anion component in the amount shown in Table 1A below. Specifically, the electrolyte (liquid component) contained 35.42 mol of azelaic acid per kg of PEDOT/PSS. In addition, the A/B ratio for the electrolytic capacitor of Example 23 was 0.42.

[Example 24]
The electrolytic capacitor of Example 24 was obtained in the same manner as in Example 22, except that methylmorpholine (MHP) was used as the second cation component, and azelaic acid and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1A below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 33.61 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 3.36 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Example 24, (A + C)/B was 0.54.

[Comparative Example 1]
The electrolytic capacitor of Comparative Example 1 was obtained in the same manner as in Example 1, except that the first cationic component was not used to obtain the polymer dispersion, and phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare the electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.03 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 29.74 mol per kg of PEDOT/PSS. Furthermore, the C/B ratio of the electrolytic capacitor of Comparative Example 1 was 1.10.

[Comparative Example 2]
An electrolytic capacitor according to Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.86 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 27.86 mol per kg of PEDOT/PSS. In addition, the C/B ratio for the electrolytic capacitor according to Comparative Example 2 was 1.00.

[Comparative Example 3]
An electrolytic capacitor according to Comparative Example 3 was obtained in the same manner as Comparative Example 1, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 28.74 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 25.87 mol per kg of PEDOT/PSS. In addition, the C/B ratio for the electrolytic capacitor according to Comparative Example 3 was 0.90.

[Comparative Example 4]
The electrolytic capacitor of Comparative Example 4 was obtained in the same manner as Comparative Example 1, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.03 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 29.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 4, (A+C)/B was 1.15.

[Comparative Example 5]
An electrolytic capacitor according to Comparative Example 5 was obtained in the same manner as in Example 1, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.86 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 27.86 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 5, (A+C)/B was 1.05.

[Comparative Example 6]
An electrolytic capacitor according to Comparative Example 6 was obtained in the same manner as in Example 1, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 38.43 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 3.84 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 6, (A+C)/B was 0.14.

[Comparative Example 7]
The electrolytic capacitor of Comparative Example 7 was obtained in the same manner as Comparative Example 4, except that the electrolyte solution (liquid component) contained only phthalic acid (FT) as the anion component in the amount shown in Table 1B below. Specifically, the electrolyte solution (liquid component) contained 40.13 mol of phthalic acid (FT) per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 7, the A/B ratio was 0.04.

[Comparative Example 8]
An electrolytic capacitor according to Comparative Example 8 was obtained in the same manner as in Example 3, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.03 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 29.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 8, (A+C)/B was 1.26.

[Comparative Example 9]
An electrolytic capacitor according to Comparative Example 9 was obtained in the same manner as in Example 3, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.86 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 27.86 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 9, (A+C)/B was 1.16.

[Comparative Example 10]
An electrolytic capacitor according to Comparative Example 10 was obtained in the same manner as Comparative Example 8, except that the electrolyte solution (liquid component) contained only phthalic acid (FT) as the anion component in the amount shown in Table 1B below. Specifically, the electrolyte solution (liquid component) contained 40.13 mol of phthalic acid (FT) per kg of PEDOT/PSS. In addition, the A/B ratio for the electrolytic capacitor according to Comparative Example 10 was 0.11.

[Comparative Example 11]
An electrolytic capacitor according to Comparative Example 11 was obtained in the same manner as in Example 6, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.03 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 29.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 11, (A+C)/B was 1.38.

[Comparative Example 12]
An electrolytic capacitor according to Comparative Example 12 was obtained in the same manner as in Example 6, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.86 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 27.86 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 12, (A+C)/B was 1.27.

[Comparative Example 13]
An electrolytic capacitor according to Comparative Example 13 was obtained in the same manner as in Example 6, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 29.68 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 23.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 13, (A+C)/B was 1.06.

[Comparative Example 14]
An electrolytic capacitor according to Comparative Example 14 was obtained in the same manner as Comparative Example 11, except that the electrolyte solution (liquid component) contained only phthalic acid (FT) as the anion component in the amount shown in Table 1B below. Specifically, the electrolyte solution (liquid component) contained 40.13 mol of phthalic acid (FT) per kg of PEDOT/PSS. In the electrolytic capacitor according to Comparative Example 14, the A/B ratio was 0.19.

[Comparative Example 15]
An electrolytic capacitor according to Comparative Example 15 was obtained in the same manner as in Example 8, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.03 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 29.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 15, (A+C)/B was 1.64.

[Comparative Example 16]
An electrolytic capacitor according to Comparative Example 16 was obtained in the same manner as in Example 8, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.86 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 27.86 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 16, (A+C)/B was 1.53.

[Comparative Example 17]
An electrolytic capacitor according to Comparative Example 17 was obtained in the same manner as in Example 8, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 29.68 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 23.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 17, (A+C)/B was 1.30.

[Comparative Example 18]
An electrolytic capacitor according to Comparative Example 18 was obtained in the same manner as in Example 11, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.03 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 29.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 18, (A+C)/B was 2.19.

[Comparative Example 19]
An electrolytic capacitor according to Comparative Example 19 was obtained in the same manner as in Example 11, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.86 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 27.86 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 19, (A+C)/B was 2.06.

[Comparative Example 20]
An electrolytic capacitor according to Comparative Example 20 was obtained in the same manner as in Example 11, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 29.68 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 23.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 20, (A+C)/B was 1.79.

[Comparative Example 21]
An electrolytic capacitor according to Comparative Example 21 was obtained in the same manner as in Example 11, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1B below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 32.89 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 16.44 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 21, (A+C)/B was 1.39.

[Comparative Example 22]
An electrolytic capacitor according to Comparative Example 22 was obtained in the same manner as in Comparative Example 4, except that 0.1059 mmol (35.29 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component to obtain the first cationic component-containing polymer dispersion. In the electrolytic capacitor according to Comparative Example 22, (A+C)/B was 2.41.

[Comparative Example 23]
An electrolytic capacitor according to Comparative Example 23 was obtained in the same manner as in Comparative Example 5, except that 0.1059 mmol (35.29 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component to obtain the first cationic component-containing polymer dispersion. In the electrolytic capacitor according to Comparative Example 23, (A+C)/B was 2.27.

[Comparative Example 24]
An electrolytic capacitor according to Comparative Example 24 was obtained in the same manner as in Comparative Example 13, except that 0.1059 mmol (35.29 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component to obtain the first cationic component-containing polymer dispersion. In the electrolytic capacitor according to Comparative Example 24, (A+C)/B was 1.99.

[Comparative Example 25]
The electrolytic capacitor of Comparative Example 25 was obtained in the same manner as in Comparative Example 21, except that 0.1059 mmol (35.29 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component to obtain the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Comparative Example 25, (A+C)/B was 1.57.

[Comparative Example 26]
The electrolytic capacitor of Comparative Example 26 was obtained in the same manner as in Comparative Example 6, except that 0.1059 mmol (35.29 mol per kg of PEDOT/PSS) of ammonia was used as the first cationic component to obtain the first cationic component-containing polymer dispersion. In the electrolytic capacitor of Comparative Example 26, (A+C)/B was 1.02.

[Comparative Example 27]
The electrolytic capacitor of Comparative Example 27 was obtained in the same manner as Comparative Example 22, except that the electrolyte solution (liquid component) contained only phthalic acid (FT) as the anion component in the amount shown in Table 1C below. Specifically, the electrolyte solution (liquid component) contained 40.13 mol of phthalic acid (FT) per kg of PEDOT/PSS. In addition, the A/B ratio for the electrolytic capacitor of Comparative Example 27 was 0.88.

[Comparative Example 28]
The electrolytic capacitor of Comparative Example 28 was obtained in the same manner as in Example 13, except that phthalic acid (FT) and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 24.03 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 26.43 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 28, (A + C)/B was 1.71.

[Comparative Example 29]
An electrolytic capacitor according to Comparative Example 29 was obtained in the same manner as in Example 13, except that phthalic acid (FT) and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 24.94 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 24.94 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 29, (A+C)/B was 1.59.

[Comparative Example 30]
An electrolytic capacitor according to Comparative Example 30 was obtained in the same manner as in Example 13, except that phthalic acid (FT) and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 26.98 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 21.58 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 30, (A+C)/B was 1.35.

[Comparative Example 31]
An electrolytic capacitor according to Comparative Example 31 was obtained in the same manner as in Example 15, except that phthalic acid (FT) and 1,2,3,4-tetramethylimidazolinium (TMI) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 21.78 mol per kg of PEDOT/PSS, and 1,2,3,4-tetramethylimidazolinium (TMI) was added in an amount of 23.96 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 31, (A+C)/B was 1.78.

[Comparative Example 32]
An electrolytic capacitor according to Comparative Example 32 was obtained in the same manner as in Example 15, except that phthalic acid (FT) and 1,2,3,4-tetramethylimidazolinium (TMI) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 22.73 mol per kg of PEDOT/PSS, and 1,2,3,4-tetramethylimidazolinium (TMI) was added in an amount of 22.73 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 32, (A+C)/B was 1.65.

[Comparative Example 33]
An electrolytic capacitor according to Comparative Example 33 was obtained in the same manner as in Example 15, except that phthalic acid (FT) and 1,2,3,4-tetramethylimidazolinium (TMI) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 24.88 mol per kg of PEDOT/PSS, and 1,2,3,4-tetramethylimidazolinium (TMI) was added in an amount of 19.91 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 33, (A+C)/B was 1.39.

[Comparative Example 34]
An electrolytic capacitor according to Comparative Example 34 was obtained in the same manner as in Example 17, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.03 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 29.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 34, (A+C)/B was 1.65.

[Comparative Example 35]
An electrolytic capacitor according to Comparative Example 35 was obtained in the same manner as in Example 17, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 27.86 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 27.86 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 35, (A+C)/B was 1.53.

[Comparative Example 36]
An electrolytic capacitor according to Comparative Example 36 was obtained in the same manner as in Example 17, except that phthalic acid (FT) and dimethylethylamine (DEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 29.68 mol per kg of PEDOT/PSS, and dimethylethylamine (DEA) was added in an amount of 23.74 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 36, (A+C)/B was 1.30.

[Comparative Example 37]
An electrolytic capacitor according to Comparative Example 37 was obtained in the same manner as in Example 20, except that phthalic acid (FT) and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 24.03 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 26.44 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 37, (A+C)/B was 1.71.

[Comparative Example 38]
The electrolytic capacitor of Comparative Example 38 was obtained in the same manner as in Example 20, except that phthalic acid (FT) and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 24.94 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 24.94 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 38, (A+C)/B was 1.59.

[Comparative Example 39]
An electrolytic capacitor according to Comparative Example 39 was obtained in the same manner as in Example 20, except that phthalic acid (FT) and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, phthalic acid (FT) was added in an amount of 26.98 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 21.59 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 39, (A+C)/B was 1.35.

[Comparative Example 40]
The electrolytic capacitor of Comparative Example 40 was obtained in the same manner as in Example 22, except that azelaic acid and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 22.26 mol per kg of PEDOT/PSS, and triethylamine (TEA) was added in an amount of 24.48 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 40, (A + C)/B was 1.76.

[Comparative Example 41]
The electrolytic capacitor of Comparative Example 41 was obtained in the same manner as in Example 22, except that azelaic acid and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 23.04 mol per kg of PEDOT/PSS, and triethylamine (TEA) was added in an amount of 23.04 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 41, (A + C)/B was 1.64.

[Comparative Example 42]
The electrolytic capacitor of Comparative Example 42 was obtained in the same manner as in Example 22, except that azelaic acid and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 24.77 mol per kg of PEDOT/PSS, and triethylamine (TEA) was added in an amount of 19.81 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 42, (A + C)/B was 1.39.

[Comparative Example 43]
The electrolytic capacitor of Comparative Example 43 was obtained in the same manner as in Example 22, except that azelaic acid and triethylamine (TEA) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 27.92 mol per kg of PEDOT/PSS, and triethylamine (TEA) was added in an amount of 13.96 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 43, (A + C)/B was 1.03.

[Comparative Example 44]
An electrolytic capacitor according to Comparative Example 44 was obtained in the same manner as in Example 24, except that azelaic acid and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 22.26 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 24.48 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor according to Comparative Example 44, (A+C)/B was 1.76.

[Comparative Example 45]
The electrolytic capacitor of Comparative Example 45 was obtained in the same manner as in Example 24, except that azelaic acid and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 23.04 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 23.04 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 45, (A + C)/B was 1.64.

[Comparative Example 46]
The electrolytic capacitor of Comparative Example 46 was obtained in the same manner as in Example 24, except that azelaic acid and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 24.77 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 19.81 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 46, (A + C)/B was 1.39.

[Comparative Example 47]
The electrolytic capacitor of Comparative Example 47 was obtained in the same manner as in Example 24, except that azelaic acid and methylmorpholine (MHP) were added to the mixed solvent in the amounts shown in Table 1C below to prepare an electrolyte solution (liquid component). Specifically, azelaic acid was added in an amount of 27.92 mol per kg of PEDOT/PSS, and methylmorpholine (MHP) was added in an amount of 13.96 mol per kg of PEDOT/PSS. In addition, in the electrolytic capacitor of Comparative Example 47, (A + C)/B was 1.03.

For Examples 1 to 24, the compositions of the conductive polymer layer and electrolyte solution, as well as (A+C)/B, are shown in Table 1A below. For Comparative Examples 1 to 24, the compositions of the conductive polymer layer and electrolyte solution, as well as (A+C)/B, are also shown in Table 1B below. For Comparative Examples 25 to 47, the compositions of the conductive polymer layer and electrolyte solution, as well as (A+C)/B, are also shown in Table 1C below.

<Evaluation>
<Initial measurement of capacitance, equivalent series resistance, and leakage current>
For each electrolytic capacitor according to each example (Examples 1 to 24 and Comparative Examples 1 to 47), the initial capacitance (unit: μF) and the initial equivalent series resistance (unit: mΩ) at a frequency of 120 kHz were measured using an LCR meter. The measurement temperature was 20°C. Measurements of the initial capacitance and initial equivalent series resistance were taken for 20 samples each, and the arithmetic mean of the obtained measurements was calculated. The arithmetic mean was used as the initial capacitance and initial equivalent series resistance value for each electrolytic capacitor according to each example. A 1 kΩ resistor was connected in series to each electrolytic capacitor according to each example, and the initial leakage current (unit: μA) was measured after applying a rated voltage of 25 V from a DC power supply for 120 seconds. The arithmetic mean of the initial leakage current values obtained for the 20 samples was used as the initial leakage current value for each electrolytic capacitor according to each example. The initial capacitance, initial equivalent series resistance, and initial leakage current for the electrolytic capacitors of Examples 1 to 24 are shown in Table 2A below. The initial capacitance, initial equivalent series resistance, and initial leakage current for the electrolytic capacitors of Comparative Examples 1 to 24 are shown in Table 2B below. The initial capacitance, initial equivalent series resistance, and initial leakage current for the electrolytic capacitors of Comparative Examples 25 to 47 are shown in Table 2C below.
<<Measurement of capacitance, equivalent series resistance, and leakage current after reflow processing>>
Assuming exposure to high temperatures during the reflow (RF) process, the electrolytic capacitors according to each example were heated at 200°C to 260°C for 70 seconds. The electrolytic capacitors according to each example were then measured for capacitance, equivalent series resistance, and leakage current after the heating process. That is, the electrolytic capacitance, equivalent series resistance, and leakage current after the reflow process were measured. These measurements were performed in the same manner as described above. For the electrolytic capacitors according to Examples 1 to 24, the electrostatic capacitance, equivalent series resistance, and leakage current after the reflow process are shown in Table 2A below. For the electrolytic capacitors according to Comparative Examples 1 to 24, the electrostatic capacitance, equivalent series resistance, and leakage current after the reflow process are shown in Table 2B below. For the electrolytic capacitors according to Comparative Examples 25 to 47, the electrostatic capacitance, equivalent series resistance, and leakage current after the reflow process are shown in Table 2C below.

Table 2A shows that the electrolytic capacitors of Examples 1 to 24 have high capacitance, low leakage current, and low equivalent series resistance even after reflow processing. On the other hand, Tables 2B and 2C show that the electrolytic capacitors of Comparative Examples 1 to 47 exhibit at least one of a decrease in capacitance, an increase in leakage current, and an increase in equivalent series resistance after reflow processing.

The electrolytic capacitor disclosed herein can be used in applications that require simultaneous suppression of capacitance reduction, leakage current increase, and equivalent series resistance increase, even after exposure to thermal stress such as reflow soldering.

10: Capacitor element, 11: Anode foil, 12: Cathode foil, 13: Separator, 14: Winding tape, 100: Electrolytic capacitor, 101: Bottomed case, 102: Sealing member, 103: Seat plate, 104A, 104B: Lead wire, 105A, 105B: Lead tab

Claims (11)

An electrolytic capacitor comprising a capacitor element and a liquid component,
The capacitor element is
an anode foil having a dielectric layer;
a cathode foil disposed so as to face the dielectric layer;
a separator interposed between the anode foil and the cathode foil;
a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator,
the conductive polymer layer includes a conductive polymer,
the solid-liquid electrolyte containing the conductive polymer layer and the liquid component contains a first cationic component, a second cationic component, and an anionic component;
the conductive polymer layer contains the first cationic component,
the liquid component includes the second cationic component and the anionic component,
In the solid-liquid electrolyte, when the ratio of the number of moles of the first cation component to the mass of the conductive polymer is A (mol/kg), the ratio of the number of moles of the anion component to the mass of the conductive polymer is B (mol/kg), and the ratio of the number of moles of the second cation component to the mass of the conductive polymer is C (mol/kg),
the ratio A, the ratio B, and the ratio C satisfy the relationship 0.20≦(A+C)/B≦1.01,
Electrolytic capacitor. An electrolytic capacitor comprising a capacitor element and a liquid component,
The capacitor element is
an anode foil having a dielectric layer;
a cathode foil disposed so as to face the dielectric layer;
a separator interposed between the anode foil and the cathode foil;
a conductive polymer layer interposed between the anode foil and the cathode foil and in contact with the separator,
the conductive polymer layer includes a conductive polymer,
the solid-liquid electrolyte containing the conductive polymer layer and the liquid component contains a first cation component and an anion component;
the conductive polymer layer contains the first cationic component,
the liquid component includes the anion component,
In the solid-liquid electrolyte, when the ratio of the number of moles of the first cation component to the mass of the conductive polymer is A (mol/kg) and the ratio of the number of moles of the anion component to the mass of the conductive polymer is B (mol/kg),
the ratio A and the ratio B satisfy the relationship 0.20≦A/B≦1.01,
Electrolytic capacitor. the ratio A, the ratio B, and the ratio C satisfy the relationship 0.20≦(A+C)/B<1,
2. The electrolytic capacitor according to claim 1. The ratio A and the ratio B satisfy the relationship 0.20≦A/B<1.
3. The electrolytic capacitor according to claim 2. The ratio A is in the range of 1 mol/kg or more and 30 mol/kg or less, the ratio B is in the range of 25 mol/kg or more and 45 mol/kg or less, and the ratio C is in the range of 1 mol/kg or more and 25 mol/kg or less.
4. The electrolytic capacitor according to claim 1 or 3. the valence of the first cationic component and the second cationic component is both 1;
4. The electrolytic capacitor according to claim 1 or 3. The pKa of the first cationic component is 10 or less.
The electrolytic capacitor according to claim 1 . the pKa of the second cationic component is 11 or less;
4. The electrolytic capacitor according to claim 1. The anion component is at least one selected from the group consisting of aromatic carboxylic acids, aliphatic carboxylic acids, and salts thereof.
5. The electrolytic capacitor according to claim 1. The aromatic carboxylic acid is at least one selected from the group consisting of o-phthalic acid, salicylic acid, and benzoic acid.
10. The electrolytic capacitor according to claim 9. The aliphatic carboxylic acid is at least one selected from the group consisting of adipic acid, azelaic acid, and sebacic acid.
10. The electrolytic capacitor according to claim 9.