JPH0364013A - Solid electrolytic capacitor and manufacture thereof - Google Patents

Abstract

PURPOSE:To enhance generation efficiency of a solid electrolyte within a fine hole and a void and improve the electrostatic capacitance and the leakage current by forming an anion interface activation agent or a non-ion interface activation agent on a dielectric oxide film which is formed on an anode surface previously and by forming a solid electrolyte consisting of a conductive polymer film. CONSTITUTION:A lead is attached to an anode foil 1 where a dielectric oxide film 2 is formed and then is dipped into sodium di(2-ethylhexyl)sulfosuccinate solution after reformation, thus forming an anion interface activation agent layer 3. Then, after this anode foil 1 is dipped into an ethanolic solution of pyrrole, it is further dipped into ammonium persulfate solution, thus forming a polypyrrole film 4 by chemical oxidation polymerization on the surface. Then, it is dipped into an acetonitrile solution containing pyrrole monomer and a supporting electrolyte and electrolytic oxidation polymerization is performed with the polypyrrole film 4 as an anode, thus forming a polypyrrole 5. After that, a cathode layer is formed and resin sheathing is provided for obtaining a solid electrolytic capacitor.

Description

[Detailed Description of the Invention] [Object of the Invention] <Industrial Application Field> The present invention is directed to a solid electrolytic capacitor using a conductive polymer such as polypyrrole or polythiophene as a solid electrolyte, and a method for manufacturing the same. .

(Prior art) A solid electrolytic capacitor with a dielectric oxide film formed on the surface of a positive I7 body made of a film-forming metal such as aluminum or tantalum, and a conductive polymer such as polypyrrole, polythiophene, polyaniline, polyfuran, etc. as an electrolyte. It has been known.

Electrolytic capacitors using these conductive polymers have lower m-degree characteristics, frequency, and tXX negative load characteristic life than electrolytic capacitors using conventional liquid electrolytes or organic semiconductors.
Although these are excellent, the efficiency of solid electrolyte generation in the micropores and voids on the anode surface is low, resulting in a decrease in capacitance and a drop in withstand voltage.

There was a problem that large tanb was likely to occur.

(Problems to be Solved by the Invention) The present invention was proposed in order to eliminate the drawbacks of the prior art as described above, and its purpose is to eliminate micropores and sintering on the surface of an anode on which a dielectric oxide film is formed. By efficiently generating a conductive polymer film in the voids of the bonded anode body, the capacitance and withstand voltage drop that occur due to lack of solid electrolyte can be reduced.

The purpose is to improve tan δ and other factors.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a method of forming in advance an anionic surfactant or a nonionic surfactant layer having a wetting and permeation effect on a dielectric oxide film formed on the surface of an anode. This is a solid electrolytic capacitor on which a solid electrolyte made of a conductive polymer film is formed, and a method for manufacturing the same. iJ! It is characterized by improving the ability to form into ultra-fine pores.

(Function) According to the solid electrolytic capacitor and the manufacturing method thereof configured as described above, the anionic surfactant formed on the surface of the dielectric oxide film improves the wettability of the oxide film surface and the i! ! Since the moisture content is significantly increased, a conductive polymer film is often formed inside the micropores formed in the dielectric oxide film, and the t
This brings about improvements in capacitor characteristics such as a reduction in an δ and an increase in the rate of appearance of capacitance.

Further, similar effects can be obtained by using a nonionic surfactant instead of an anionic surfactant.

Note that even in a capacitor element formed by winding an anode foil and a cathode foil with a dielectric oxide film formed thereon with a separator paper in between, by forming the surfactant on the anode surface or on the anode surface and the cathode surface in advance, A similar effect can be obtained.

(Example) Example 1 As shown in Fig. 1, a high-purity etched aluminum foil was roughened and then 90V was applied in an ammonium adipate aqueous solution to form a dielectric coating g$2. A lead was attached to the anode foil 1, and after reconstitution, it was immersed in a 1% aqueous solution of sodium di(2-ethyl)hexylsulfosuccinate for 10 minutes, washed with water, and dried.
was formed. Next, this anode foil 1 was immersed in a pyrrole-ethanol solution for 10 minutes W1, and then further immersed in an aqueous ammonium persulfate solution for 10 minutes to coat the surface with polypyrrol It! by chemical oxidation polymerization. J4 was formed. Next, it was immersed in an acetonitrile solution containing a pyrrole monomer and a supporting electrolyte, and electrolytic oxidative polymerization was performed for 120 minutes using the polypyrrole WA4 formed by the chemical oxidative polymerization as an anode for 120 minutes to form polypyrrole 5. Thereafter, colloidal carbon 6 and silver paste 7 were applied and dried to form a cathode layer, and a resin exterior was applied to obtain a solid electrolytic capacitor.

In Example 1, a 0.1% aqueous solution of polyethylene glycol nonylphenyl ether (10T adduct of ethylene oxide) was used instead of the anionic surfactant to form a nonionic surfactant layer.

Thereafter, in the same manner as in Example 1, a polypyrrole film by chemical oxidation polymerization, a polypyrrole film by electrolytic oxidation polymerization, colloidal carbon 6 and silver paste 7 were formed, and an exterior was applied to obtain a solid electrolytic condenser.

Example 3 In Example 2, the reconstituted anode foil, separator paper, and cathode foil were each immersed in a 1% aqueous solution of sodium di(2-ethyl>hexylsulfosuccinate) to form the anionic surfactant layer. A capacitor element was fabricated by winding it.

Thereafter, each polypyrrole film was formed by chemical and oxidative polymerization in the same manner as in Example 2, and the outer casing was removed to obtain a solid electrolytic capacitor.

Example 4 A porous sintered body of aluminum powder was treated in an ammonium adibate aqueous solution to form a dielectric oxide film, thereby producing an anode element. This anode element was immersed in a 0.5% aqueous solution of polyethylene glycol nonylphenyl ether (15 moles of ethylene oxide) for 30 minutes, and then washed with water.

It was dried. Next, a polypyrrole layer was formed by chemical oxidation polymerization and a polypyrrole layer was formed by electrolytic oxidation polymerization in the same manner as in Example 2. After that, colloidal carbon and silver paste were applied and dried to form a cathode layer, and a resin exterior was applied. A solid electrolytic capacitor was obtained.

Example 5 As shown in Figure 2, a high-purity etched aluminium plate (
700 μm rL> was cut into a certain size, anodized in phosphoric acid, and then 90 μm thick in ammonium adipate aqueous solution.
V is applied to form a dielectric oxide film 12 to form an anode 11. The anode 11 on which insulation disease 18 was formed by applying #l fat to this side was immersed in a 0.1% aqueous solution of polyethylene glycol lauryl ether (ethylene oxide 12 mole adduct) for 10 minutes, and then washed with water.

A surfactant layer 13 was formed by drying.

Next, chemical oxidative polymerization and electrolytic PIIF were performed in the same manner as in Example 2.
! After forming polypyrrole 114e by i-polymerization, colloidal carbon 16 was applied to the surface, air-dried, and then laminated as shown in FIG. 2, followed by heating and drying. positive l4i11
A silver paste layer 15 was formed on the end of the colloidal carbon 16 and the end of the colloidal carbon 16 to serve as an anode and a cathode, respectively.

Thereafter, a resin outer device 9 was applied to obtain a solid electrolytic capacitor.

Reference Example 1 Same as Example 1 and rF4 except that a 1% aqueous solution of lauryltrimethylammonium bromide was used as a cationic surfactant instead of sodium di(2-ethyl)-hexylsulfosuccinate. A solid electrolytic capacitor was obtained.

Reference PA2 A solid electrolytic capacitor was obtained in the same manner as in Example 1 except that sodium di(2-ethyl>-hexylsulfosuccinate was omitted).

The characteristics of the embodiments and reference examples described above are shown in the vestibule.

Table The surfactant used in the present invention is preferably an anion (anion) surfactant whose anionic moiety exhibits surface activity and a surfactant that does not have a group that dissociates into ions, preferably an anionic surfactant. Examples include a dialkyl sulfosuccinate salt (aerosol/OT) represented by the general formula % and a monobranched alkylbenzene sulfonate salt of a second-hand higher alcohol sulfate ester represented by R,〉Crow0803Na.

The total number of carbon atoms is 14 to 20, such as α-sulfo fatty acid alkyl ester base, and the hydrophilic group (-8o
Suitable are those in which Na, -0803Na) are located, and C- as a nonionic surfactant.
Among intermediate to higher alcohol/ethylene oxide adducts of 8 to 16 and alkylphenol/ethylene oxide adducts, those with an added mole of ethylene oxide of 5 to 15 are suitable for dielectric oxide films of aluminum and tantalum. It has been found.

Further, although the case where polypyrrole is used as the solid electrolyte has been described, polythiophene, polyaniline, and polyfuran have the same effect.

[Effects of the Invention] According to the solid electrolytic capacitor and the manufacturing method thereof according to the present invention, in a solid electrolytic capacitor using a conductive polymer as an electrolyte, the anode surface or the anode surface and the cathode surface on which a dielectric oxide film is formed. By forming an anionic or nonionic surfactant layer in advance, the pores and
The production efficiency of the solid electrolyte in the void increases, and the capacitance l, tan δ, leakage m flow, etc. of the capacitor can be significantly improved.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a sectional view for explaining the element structure of a solid electrolytic capacitor according to Example 1, and FIG. 2 is a cross-sectional view for explaining the element structure of a solid electrolytic capacitor according to Example 5. FIG. 1... lil polar foil 2... dielectric oxide film 3... surfactant disease 4... polypyrrole film by chemical oxidative polymerization 5... polypyrrole film by electrolytic oxidative polymerization 6... colloidal carbon 7 ...Silver paste...Anode 12...Dielectric oxide film 3...
・Surfactant disease 14...Polypyrrole film 5...Silver paste 16...Colloidal carbon 8...Insulating layer 19...Exterior resin Applicant Applicant Marcon Electronics Co., Ltd. Nippon Carlit Co., Ltd.

Claims (4)

[Claims] (1) In a solid electrolytic capacitor consisting of an anode and a cathode made of a film-forming metal with a dielectric oxide film formed on at least the surface, and a solid electrolyte of a conductive polymer film, at least the surface of the dielectric oxide film in contact with the solid electrolyte is A solid electrolytic capacitor characterized by forming a surfactant layer. (2) The solid electrolytic capacitor according to claim (1), wherein the surfactant is an anionic surfactant or a nonionic surfactant. (3) Claim (1) or (2) wherein the solid electrolyte is polypyrrole, polythiophene, polyaniline, or polyfuran.
The solid electrolytic capacitor described. (4) The method for manufacturing a solid electrolytic capacitor according to any one of claims (1) to (3), wherein the solid electrolyte is formed after forming the surfactant layer.