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EP-4737520-A1 - CONDUCTIVE COMPOSITE DISPERSION LIQUID AND METHOD FOR PRODUCING SAME, CAPACITOR AND METHOD FOR PRODUCING SAME, AND CONDUCTIVE MULTILAYER BODY AND METHOD FOR PRODUCING SAME

EP4737520A1EP 4737520 A1EP4737520 A1EP 4737520A1EP-4737520-A1

Abstract

A conductive composite dispersion liquid contains a conductive composite containing a π-conjugated conductive polymer and a polyanion, water, a sugar alcohol having 4 to 7 carbon atoms and 3 to 7 hydroxy groups in a molecule, and polyvinylpyrrolidone, and the conductive composite dispersion liquid has a viscosity at 25°C of less than 50 mPa·s.

Inventors

  • ICHIKAWA, MUNEKI

Assignees

  • Shin-Etsu Polymer Co., Ltd.

Dates

Publication Date
20260506
Application Date
20240618

Claims (14)

  1. A conductive composite dispersion liquid comprising a conductive composite containing a π-conjugated conductive polymer and a polyanion, water, a sugar alcohol having 4 to 7 carbon atoms and 3 to 7 hydroxy groups in a molecule, and polyvinylpyrrolidone, the conductive composite dispersion liquid having a viscosity at 25°C of less than 50 mPa·s.
  2. The conductive composite dispersion liquid according to claim 1, wherein a content of the polyvinylpyrrolidone is 0.01 parts by mass or more and less than 0.30 parts by mass with respect to a total of 100 parts by mass of the conductive composite and the water.
  3. The conductive composite dispersion liquid according to claim 2, wherein a content of the conductive composite is 0.1 parts by mass or more and 3.0 parts by mass or less with respect to a total of 100 parts by mass of the conductive composite and the water.
  4. The conductive composite dispersion liquid according to claim 3, wherein a content of the water is 70 mass% or more and 99 mass% or less with respect to a whole mass of the conductive composite dispersion liquid.
  5. The conductive composite dispersion liquid according to claim 4, wherein the sugar alcohol contains at least one of sorbitol, mannitol, erythritol, and pentaerythritol.
  6. The conductive composite dispersion liquid according to claim 5, further comprising an organic solvent having a boiling point at 1 atm of 150°C or more.
  7. The conductive composite dispersion liquid according to claim 6, further comprising a neutralizer.
  8. The conductive composite dispersion liquid according to claim 5, wherein the π-conjugated conductive polymer is poly(3,4-ethylenedioxythiophene) or the polyanion is polystyrenesulfonic acid, or the π-conjugated conductive polymer is poly(3,4-ethylenedioxythiophene) and the polyanion is polystyrenesulfonic acid.
  9. A capacitor comprising: an anode formed from a porous body of a valve metal; a dielectric layer formed from an oxide of the valve metal; a cathode formed from a conductive material on a side opposite to the anode; and a solid electrolyte layer formed between the dielectric layer and the cathode, wherein the solid electrolyte layer is a cured product of the conductive composite dispersion liquid according to any one of claims 1 to 8.
  10. A conductive multilayer body comprising a substrate and a conductive layer formed on a surface of at least a portion of the substrate, wherein the conductive layer is a cured product of the conductive composite dispersion liquid according to any one of claims 1 to 8.
  11. A method for producing a conductive composite dispersion liquid, the method comprising a step of mixing a conductive composite containing a π-conjugated conductive polymer and a polyanion, a dispersion medium, and a sugar alcohol having 4 to 7 carbon atoms and 3 to 7 hydroxy groups in a molecule to obtain a conductive composite dispersion liquid having a viscosity at 25°C of less than 50 mPa·s.
  12. The method for producing a conductive composite dispersion liquid according to claim 11, wherein a dispersion liquid in which the conductive composite is dispersed in the dispersion medium is obtained and condensed, and the sugar alcohol is mixed.
  13. A method for producing a capacitor, the method comprising a step of applying the conductive composite dispersion liquid according to any one of claims 1 to 8 to a surface of a dielectric layer formed on a surface of an anode formed from a porous body of a valve metal and drying the conductive composite dispersion liquid to form a solid electrolyte.
  14. A method for producing a conductive multilayer body, the method comprising a step of applying the conductive composite dispersion liquid according to any one of claims 1 to 8 to at least a surface of a substrate and drying the conductive composite dispersion liquid to form a conductive layer.

Description

Field The present invention relates to a conductive composite dispersion liquid containing a π-conjugated conductive polymer and a polyanion, a capacitor, and a conductive multilayer body. The present application claims priority based on Japanese Patent Application No. 2023-108090, filed June 30, 2023, the content of which is incorporated herein by reference. Background A polyanion having an anionic group is doped into a π-conjugated conductive polymer having a π-conjugated main chain to form a conductive composite, resulting in dispersibility in water. A method for producing a capacitor by applying a coating material in which a conductive composite dispersion liquid containing a conductive composite is used as a material to a dielectric layer disposed on the surface of an anode formed from a valve metal, drying the coating material to form a solid electrolyte layer, and arranging a cathode so as to face the solid electrolyte layer is disclosed (e.g., Patent Literature 1). In this disclosure, the coating material that contains a specific unsaturated aliphatic alcohol compound improves the performance of the capacitor. Citation List Patent Literature Patent Literature 1: Japanese Patent Application Laid-open No. 2022-071400 Summary Technical Problem In order to penetrate a porous structure of a dielectric layer, a conductive composite dispersion liquid used in production of a capacitor is required to have a low viscosity. Meanwhile, the conductive composite dispersion liquid having penetrated is required to increase in viscosity as drying and solidification progress and to stably remain in the porous structure. In order to stably retain the conductive composite dispersion liquid in the porous structure, adding a thickener is considered, but the thickener increases the viscosity of the conductive composite dispersion liquid. Therefore, a conductive composite dispersion liquid that has a low viscosity sufficiently to penetrate the porous structure and increases in viscosity during drying after penetration has been required. The present invention provides a conductive composite dispersion liquid suitable for production of a high-performance capacitor. Solution to Problem [1] A conductive composite dispersion liquid containing a conductive composite containing a π-conjugated conductive polymer and a polyanion, water, a sugar alcohol having 4 to 7 carbon atoms and 3 to 7 hydroxy groups in a molecule, and polyvinylpyrrolidone, the conductive composite dispersion liquid having a viscosity at 25°C of less than 50 mPa·s.[2] The conductive composite dispersion liquid according to [1], wherein a content of the polyvinylpyrrolidone is 0.01 parts by mass or more and less than 0.30 parts by mass with respect to a total of 100 parts by mass of the conductive composite and the water.[3] The conductive composite dispersion liquid according to [1] or [2], wherein a content of the conductive composite is 0.1 parts by mass or more and 3.0 parts by mass or less with respect to a total of 100 parts by mass of the conductive composite and the water.[4] The conductive composite dispersion liquid according to any one of [1] to [3], wherein a content of the water is 70 mass% or more and 99 mass% or less with respect to a whole mass of the conductive composite dispersion liquid.[5] The conductive composite dispersion liquid according to any one of [1] to [4], wherein the sugar alcohol contains at least one of sorbitol, mannitol, erythritol, and pentaerythritol.[6] The conductive composite dispersion liquid according to any one of [1] to [5], further containing an organic solvent having a boiling point at 1 atm of 150°C or more.[7] The conductive composite dispersion liquid according to any one of [1] to [6], further containing a neutralizer.[8] The conductive composite dispersion liquid according to any one of [1] to [7], wherein the π-conjugated conductive polymer is poly(3,4-ethylenedioxythiophene) or the polyanion is polystyrenesulfonic acid, or the π-conjugated conductive polymer is poly(3,4-ethylenedioxythiophene) and the polyanion is polystyrenesulfonic acid.[9] A capacitor including an anode formed from a porous body of a valve metal, a dielectric layer formed from an oxide of the valve metal, a cathode formed from a conductive material on a side opposite to the anode, and a solid electrolyte layer formed between the dielectric layer and the cathode, wherein the solid electrolyte layer is a cured product of the conductive composite dispersion liquid according to any one of [1] to [8].[10] A conductive multilayer body including a substrate and a conductive layer formed on a surface of at least a portion of the substrate, wherein the conductive layer is a cured product of the conductive composite dispersion liquid according to any one of [1] to [8].[11] A method for producing a conductive composite dispersion liquid, the method including a step of mixing a conductive composite containing a π-conjugated conductive polymer and a po