Solid electrolytic capacitor and method for producing the same

• US 6,466,421 B1
• Filed: 01/19/2000
• Issued: 10/15/2002
• Est. Priority Date: 05/21/1998
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Inventors: Monden, Ryuji, Sakai, Atsushi, Konuma, Hiroshi, Furuta, Yuji, Shirane, Koro, Ohata, Hideki, Sawaguchi, Toru, Yamazaki, Katsuhiko, Ikenoue, Yoshiaki
• Primary Examiner(s): Jackson, Stephen W.
• Application Number:
  US09/487,329
• Time in Patent Office: 1,000 Days
• Field of Search: 361/15, 361/115, 361/58
• US Class Current: 361/15
• CPC Class Codes: H01G 9/012 specially adapted for solid capacitors
• CPC Class Codes: H01G 9/022 Electrolytes; Absorbents
• CPC Class Codes: H01G 9/028 Organic semiconducting electrolytes, e.g. TCNQ

Abstract

Disclosed are a solid electrolytic capacitor comprising a valve-acting metal, an oxide dielectric layer formed on a surface of the valve-acting metal and a solid electrolyte layer provided on the dielectric film layer, in which the electrically conducting polymer composition layer contains as a dopant at least one anion selected from (1) an alkoxy-substituted naphthalene monosulfonate anion, (2) a heterocyclic sulfonate anion, and (3) an anion of an aliphatic polycyclic compound or a combination thereof with another anion having a dopant ability and a method for producing such a solid electrolytic capacitor.

The solid electrolytic capacitor of the invention is excellent in voltage resistance, high frequency property, tan δ, leakage current, heat resistance (reflow property), etc.

Claims

1. A method for producing a solid electrolytic capacitor comprising an oxide dielectric film having provided thereon an electrically conducting polymer composition layer, the method comprising polymerizing a polymerizable monomer compound on an oxide dielectric film by an oxidizing agent, wherein the polymerizable monomer compound is a compound represented by the following general formula (III):

wherein R¹ and R² each independently represents any one monovalent group selected from hydrogen, a linear or branched, saturated or unsaturated alkyl group having from 1 to 6 carbon atoms, a linear or branched, saturated or unsaturated alkoxy group having from 1 to 6 carbon atoms, a hydroxyl group, a halogen atom, a nitro group, a cyano group, a trihalomethyl group, a phenyl group and a substituted phenyl group, R¹ and R² may be combined to each other at any position to form at least one divalent chain for forming at least one 5-, 6- or 7-membered saturated or unsaturated ring structure, and X represents a hetero atom selected from S, O, Se, Te or NR³, R³ represents hydrogen, a linear or branched, saturated or unsaturated alkyl group having form 1 to 6 carbon atoms, a phenyl group or a linear or branched, saturated or unsaturated alkoxy group having from 1 to 6 carbon atoms, the alkyl group and the alkoxy group represented by R¹, R² or R³ may optionally contain in the chain thereof a carbonyl bond, an ether bond, an ester bond, an amide bond or an imino bond, and the polymerization reaction takes place in the presence of a compound capable of providing at least one organic anion selected from (1) an alkoxy-substituted naphthalene monosulfonate anion substituted by at least one linear or branched, saturated or unsaturated alkoxy group having from 1 to 12 carbon atoms, (2) a sulfonate anion of a heterocyclic compound having a 5- or 6-membered heterocyclic ring, and (3) an anion of an aliphatic polycyclic compound.

2. The method for producing a solid electrolytic capacitor as claimed in claim 1, wherein the polymerizable monomer compound represented by formula (III) is a compound represented by the following general formula (IV):

wherein R⁴ and R⁵ each independently represents hydrogen, a linear or branched, saturated or unsaturated alkyl group having from 1 to 6 carbon atoms, or a substituent for forming at least one 5-, 6- or 7-membered heterocyclic structure containing the two oxygen elements shown in the formula by combining the linear or branched, saturated or unsaturated alkyl groups having from 1 to 6 carbon atoms to each other at any position.

3. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing a polymerizable monomer compound and a step of dipping the metal anode foil in a solution containing an oxidizing agent and above-described organic anion.

4. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing an oxidizing agent and a step of dipping the metal anode foil in a solution containing a polymerizable monomer compound and above-described organic anion.

5. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing an oxidizing agent and then a step of dipping the metal anode foil in a solution containing a polymerizable monomer compound and above-described organic anion.

6. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing a polymerizable monomer compound and then a step of dipping the metal anode foil in a solution containing an oxidizing agent and above-described organic anion.

7. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing an oxidizing agent and above-described organic anion and then a step of dipping the metal anode foil in a solution containing a polymerizable monomer compound.

8. The method for producing a solid electrolytic capacitor as. claimed in claim 1 or 2, wherein said method comprises a step of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing a polymerizable monomer compound and above-described organic anion and then a step of dipping the metal anode foil in a solution containing an oxidizing agent.

9. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of repeating multiple times a process of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing an oxidizing agent and above-described organic anion and then a process of dipping the metal anode foil in a solution containing a polymerizable monomer compound.

10. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of repeating multiple times a process of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing a polymerizable monomer compound and above-described organic anion and then a process of dipping the metal anode foil in a solution containing an oxidizing agent.

11. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of repeating multiple times a process of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing an oxidizing agent and then a process of dipping the metal anode foil in a solution containing a polymerizable monomer compound and above-described organic anion.

12. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of repeating multiple times a process of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing a polymerizable monomer compound and then a process of dipping the metal anode foil in a solution containing an oxidizing agent and above-described organic anion.

13. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of repeating multiple times a process of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing an oxidizing agent and above-described organic anion and then a process of dipping the metal anode foil in a solution containing a polymerizable monomer compound, followed by a step of washing and drying the metal anode foil.

14. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of repeating multiple times a process of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing a polymerizable monomer compound and above-described organic anion and then a process of dipping the metal anode foil in a solution containing an oxidizing agent, followed by a step of washing and drying the metal anode foil.

15. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of repeating multiple times a process of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing an oxidizing agent and then a process of dipping the metal anode foil in a solution containing a polymerizable monomer compound and above-described organic anion, followed by a step of washing and drying the metal anode foil.

16. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein said method comprises a step of repeating multiple times a process of dipping a valve-acting metal anode foil having formed thereon an oxide dielectric film layer in a solution containing a polymerizable monomer compound and then a process of dipping the metal anode foil in a solution containing an oxidizing agent and above-described organic anion, followed by a step of washing and drying the metal anode foil.

17. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein the organic anion is an alkoxy-substituted naphthalene monosulfonate anion substituted by at least one linear or branched, saturated or unsaturated alkoxy group having from 1 to 12 carbon atoms.

18. The method for producing a solid electrolytic capacitor as claimed in claim 17, wherein at least one hydrogen on an aromatic ring of the alkoxy-substituted naphthalene monosulfonate anion is substituted by a substituent selected from a halogen atom, a nitro group, a cyano group, and a trihalomethyl group.

19. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein the organic anion is a heterocyclic sulfonate anion.

20. The method for producing a solid electrolytic capacitor as claimed in claim 19, wherein the heterocyclic sulfonate anion is an anion having at least one heterocyclic skeleton selected from the group consisting of compounds containing a chemical structure of morpholine, piperidine, piperazine, imidazole, furan, 1,4-dioxane, benzimidazole, benzothiazolylthio, benzisoxazole, benzotriazole or benzofuran.

21. The method for producing a solid electrolytic capacitor as claimed in claim 19, wherein the heterocyclic sulfonate anion contains at least one alkylsulfonate substituent in the chemical structure thereof.

22. The method for producing solid electrolytic capacitor as claimed in claim 1 or 2, wherein the organic anion as a dopant is an anion of an aliphatic polycyclic compound.

23. The method for producing a solid electrolytic capacitor as claimed in claim 1 or 2, wherein the oxidizing agent is a persulfate.

24. The method for producing a solid electrolytic capacitor as claimed in claim 2, wherein the 5-, 6- or 7-membered heterocylic structure containing the two oxygen elements shown in formula (IV) is a substituted vinylene group or a substituted o-phenylene group.