JPS63248054A - Conductive high-molecular electrode material and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a conductive high-molecular electrode material having both high ion permeability and adhesiveness to a substrate, by forming an electrolytic polymer of an aromatic compound in two kinds of insulating high- molecular films, which are laid on an electrode followed by extraction-removing the upper layer insulating high-molecular film only. CONSTITUTION:An electrolytic polymer of an aromatic compound, is composed electrochemically into two kinds of laminated high-molecular films 1 and 2, and only the high-molecular film of the upper layer 1 is extracted and removed from the obtained composite film. Thereby, a conductive electrode material being porous and having high ion diffusion speed and high electrode adhesiveness can be obtained and high molecular electrodes of various structures can be formed from this film depending upon its material for being used as an electrode material for a cell and an electrode for an electrochromic element.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new conductive polymer electrode material that can be used in various electrochemical devices and a method for producing the same.

[Conventional technology]

Conventionally, methods for obtaining conductive polymer electrode materials include (1
) a method of chemically polymerizing conductive polymers onto an electrode substrate;
(2) A method of electrochemically oxidizing and polymerizing an aromatic compound on an electrode substrate is known. Such conductive polymer electrodes are expected to be in demand as electrodes for batteries and electrochromics. In order to improve properties as an electrode material, it is desirable to have a film that has a high ion diffusion rate within the film, a low internal resistance, and excellent adhesion to the electrode.

Polyacetylene has been studied as a representative example of (1) above. Polyacetylene film is fibrous and provides a porous film with a large surface area. Therefore, it is attracting attention as a film-like battery material because it easily incorporates a large amount of ions and its low conductivity changes through electrochemical doping of ions. As an example of (2), electropolymerized conductive films of polypyrrole, polythiophene, polyaniline, etc. obtained by electrochemically oxidizing virol, thiophene, aniline, etc. have been studied. The structure of these polymer films can be changed by changing the voltage, substrate, solvent, and electrolyte, and ions can be reversibly doped/undoped by voltage application, and the amount of ions that can be contained is large, so they can be used as battery materials. It is being researched as Furthermore, since a reversible color change occurs with the above reaction, its application to display elements is also being studied.

[Problem that the invention seeks to solve]

Although polyacetylene film has good properties as an electrode material, it is unstable in the atmosphere and is extremely difficult to handle. On the other hand, electrolytically polymerized films have excellent stability and can change the film structure and electrochemical properties depending on the polymerization conditions, but the structures that can be obtained by changing the polymerization conditions are limited and generally have a uniform structure and porous It is difficult to realize a layered structure with high quality, excellent ion diffusivity, and excellent adhesion. The present inventors have already discovered that a new conductive polymer film can be obtained by electrochemically compounding an electrolytic polymer of an aromatic compound into an insulating polymer film (
Japanese Patent Application No. 58-186991, No. 58-215201, No. 58-215204). In other words, a conductive polymer film produced by electrolytic polymerization is produced by placing a common electrode substrate on a counter electrode in a solution containing an aromatic compound that will become a monomer for electrolytic polymerization and an electrolyte for conducting electricity in an organic solvent such as acetonitrile. K
It is well formed. At this time, if the electrode substrate is coated with an insulating polymer film, no current can be passed and no conductive film is formed at all. However, the present inventors applied various types of polymer films on electrode substrates and combined them with an appropriate electrolytic reaction solution that does not dissolve the films, thereby allowing the electrolytic reaction to proceed in the same way as on ordinary electrodes. It was discovered that a composite film of an insulating polymer and an electrolytically polymerized polymer can be obtained.

Furthermore, the present inventors extracted and removed the insulating polymer from the composite film using a solvent, and developed a film with excellent ion permeability that is asymmetrical in the film thickness direction (Japanese Patent Application No. 1986-12).
No. 5654). Although this film has improved ion permeability in the membrane compared to conventional electropolymerized films, it peels off from the electrode during extraction, making it difficult to improve adhesion to the electrode.

An object of the present invention is to provide a conductive polymer electrode material that eliminates the conventional drawbacks and has both high ion permeability and adhesion to a substrate, and a method for manufacturing the same.

[Means for solving problems]

To summarize the present invention, the first invention relates to a conductive polymer electrode material, in which an electrolytic polymer of an aromatic compound is contained in two types of insulating polymer films coated on an electrode. It is characterized in that it is a material obtained by extracting and removing only the upper layer of the insulating polymer film after formation.

The second invention of the present invention relates to a method for manufacturing a conductive polymer electrode material, which includes a step of coating a lower layer of an insulating polymer film on the electrode, and a step of coating an upper layer of an insulating polymer film on the electrode. a step of electrolytically polymerizing an aromatic compound on the electrode substrate with the film to composite the polymer of the aromatic compound into the lower and upper polymer films; It is characterized by including each step of extracting and removing only the molecular film.

Specifically, the electrode material of the present invention is an electropolymerized composite film formed on an electrode such as a metal, and as shown in FIG. It is characterized by having layers. That is, FIG. 1 is a schematic cross-sectional view showing the structure of the conductive polymer electrode material of the present invention, where 1 is the porous electropolymerized layer after the upper insulating polymer film has been extracted and removed, and 2 is the lower layer. Insulating polymer-electrolytically polymerized polymer composite layer, S means an electrode.

The aromatic compound that provides the electrolytic polymer that can be used in the present invention may be any compound that can be electrolytically polymerized, such as Ehahirol, 3-methylvirol, 11-methylvirol, N-
phenylvirol, thiophene, furan, phenol,
3-Methylthiophene, 5-ethylthiophene, 3-propylthiophene, 3-methoxythiophene, selenophene, tellurophene, biphenyl, azulene, aniline, isothianaphthene, carbazole, p-terphenyl, 0-terphenyl, biteophene, α- Examples include aromatic compounds such as terchenyl and pyrene.

Next, as the electrolyte for electrolytic polymerization, any electrolyte that is normally used in electrolytic polymerization may be used, such as organic quaternary ammonium salts, inorganic salts, protonic acids, esters, and other common compounds. Polyanions can also be used.

As the solvent, acetonitrile or an acetonitrile/nitrobenzene mixed solvent is usually used, but any solvent can be used as long as it is capable of electrolytically polymerizing aromatic compounds and can dissolve an appropriate electrolyte and conduct electricity.

The lower insulating polymer film coated on the electrode can form a uniform thin film, swells slightly in the polymerization solvent, and has good adhesion to the electrode, allowing the upper insulating polymer film to be extracted and removed. It can be used as long as it is insoluble in the solvent used. As such a film, for example, novolac resin, methacrylate polymer material, polyimide, rubber polymer material, etc. can be used.

As the upper insulating polymer film material to be coated on the electrode with the lower polymer film, any material can be used as long as it can form a uniform film and can be extracted and removed with a solvent after composite formation.

Examples of such film materials include polyvinyl chloride resins, polystyrene resins, and acrylate resins.

On the other hand, as a substrate for electrolytic polymerization, noble metals such as gold, platinum, and palladium, metals with oxide films such as chromium, titanium, and stainless steel, or conductive metal oxides such as tin oxide and indium oxide, or appropriate combinations of these can be used. It is possible to use a material deposited on a substrate by, for example, plating, vapor deposition, sputtering, or the like, and it is also possible to continuously manufacture the material using a strip-shaped metal foil electrode.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.
The invention is not limited to these examples.

Example 1 After evaporating 10 nm of chromium onto a T1 foil substrate, polyglycidyl methacrylate was spin-coded to a thickness of α1μ. After drying, polyvinyl chloride (molecule i near 000
A film having a thickness of 20 μm was formed from the methyl ethyl keto/-tetrahydrofuran mixed solution of Example 0) by a casting method.

This film-coated substrate was placed in an electrolytic solution containing a mixed solution of acetonitrile/nitrobenzene (4:1), 0.3 mol/l of tetraethelammonium verchlorate, and 1 mol/l of thiophene, and a platinum-coated titanium electrode was placed as a counter electrode. t6 for the silver/silver ion electrode, immersed as
A black composite film was obtained by electrolytically polymerizing the charge amount: 10/a/deophene at a potential of v. After polymerization, the composite film with electrodes was immersed in tetrahydrofuran for 60 minutes to remove polyvinyl chloride. When the surface of the film after extraction was observed with a scanning electron microscope, it was found that 1μ
A porous electrode material with roughness comparable to that of a ridge was obtained. The adhesion between the extracted film and the chromium-coated titanium electrode was high, and no peeling occurred between the film and the electrode even when the doping/dedoping reaction was performed in acetonitrile. The same polymerization conditions (potential:
Comparing the magnitude of the doping current peak value of the polythiophene film produced at 1.6V, charge amount: 10/i) and the film obtained by the present invention, it is found that the peak value of the film obtained by the present invention is 15%. Improved.

Example 2 After evaporating 10 nm of chromium onto a T1 foil substrate, polyglycidyl methacrylate was spin-coded to a thickness of L2μ and cured at 100° C. for 30 minutes.

After drying, a film having a thickness of 20 μm was formed from a mixed solution of polyvinyl chloride (molecular weight: 70,000) in methyl ethyl ketone and tetrahydrofuran by a casting method. A platinum-coated titanium electrode was placed as a counter electrode in an electrolytic solution prepared by dissolving Q, 3 mol/l of tetraethylammonium verchlorate, and 1 mol/l of thiophene in a mixed solution of total acetonitrile/nitrobenzene (4:1). A black composite film was obtained by electrolytically polymerizing thiophene by a charge amount of 1.50/crl at a potential of 1.8 V with respect to a silver/silver ion electrode. After polymerization, the composite film with electrodes was immersed in tetrahydrofuran for 60 minutes to remove polyvinyl chloride. When the surface of the film after extraction was observed with a scanning electron microscope, irregularities of about 1.5 microns were observed on the surface, indicating that a porous electrode material was obtained. The adhesion between the extracted film and the chromium-coated titanium electrode was high, and even when the doping/dedoping reaction was performed in acetonitrile, the film and electrode did not peel off. The same polymerization conditions (potential: 1.8 V, charge amount:
Comparing the magnitude of the doping current peak value between the polythiophene film produced using t 5 C/ tJ ) and the film obtained according to the present invention, the peak value was improved by 12 cm, etc. in the film obtained according to the present invention.

Example 5 The same substrate as in Example 1 was used, and a novolac resin having a thickness of 12 μm was coated as the lower layer insulating polymer film material, and a 25 Pm polyvinyl chloride was coated as the upper layer insulating polymer film material. This film-based substrate was added to a mixed solution of acetonitrile/nitrobenzene (4:1) at 15 mol/l.
A platinum-coated titanium electrode was immersed as a counter electrode in an electrolytic solution containing 1 mol/l of tetraethylammonium paratoluenesulfonate and 1 mol/l of virol, and the electrode was immersed at a potential of 1.2 V with respect to the silver/silver ion electrode. 5/
A black composite film was obtained by electrolytically polymerizing virole with a charge amount of . After polymerization, the composite film with electrodes was immersed in tetrahydrofuran for 60 minutes to remove polyvinyl chloride. When the surface of the film after extraction was observed with a scanning electron microscope, fine irregularities of 15 to zOμ inertia' were observed on the surface. The conductive polymer electrode obtained in the present invention is made of tetraethelammonium paratoluenesulfonate =
The sample was immersed in acetonitrile containing 11'mol/2, and doping/undoping of paratoluenesulfonate anion was repeated. Even after repeating doping/dedoping more than 500 times, the film did not peel off from the metal electrode. The doping current used the same electrode without film coating, and the same polymerization conditions (potential: t2V, charge amount = α80/51"
), a value 20 cm larger was obtained compared to the polypyrrole film produced in

Example 4 A gold coated plastic electrode with a thickness of L5m was coated with polyglycidyl methacrylate having a thickness of αIPg as the lower layer insulating polymer film material and vinylidene fluoride-trifluoride with a thickness of approximately 15 μm as the upper layer insulating polymer film material. Ethylene copolymer (copolymerization ratio 52.5: 47.5
) was coated.

This film-coated substrate was washed with ethanol/acetonitrile (
A gold-coated glass electrode was immersed as a counter electrode in an electrolyte solution containing 100 mol/l of tetraethylammonium paratoluenesulfonate and 1 morph of virol dissolved in a mixed solution of 4:1), and a silver/silver ion electrode was used. against t
When virol was electrolytically polymerized at a potential of 2 V and a charge amount of t 50 /cJ, a black composite film was obtained. After polymerization, the composite film with electrodes was placed in acetonitrile for 6 hours.
The sample was immersed for 0 minutes to remove the vinylidene fluoride-trifluoroethylene copolymer.

When the surface of the film after extraction was observed with a scanning electron microscope, the surface was observed to have a pine mushroom shape with a thickness of 1 to 20 μm. The conductive polymer electrode obtained in the present invention was made of tetraethylammonium para-toluene sulfonate: α1 mol/
1 was immersed in tr-containing acetonitrile, and doping/dedoping of para-toluenesulfonate anion was repeated. Even after repeating doping/dedoping more than 500 times, the film did not peel off from the metal electrode.

For the doping current, an electrode not coated with an insulating film was used under the same polymerization conditions (potential: t2V).

Compared to the polypyrrole film prepared with charge amount: t50/J), a value 12 times larger was obtained.

Example 5 A platinum-coated titanium substrate was used, and the lower insulating polymer film material was coated with 11 μm thick nylon, and the upper layer was coated with 20 μm polyvinyl alcohol.

This film-coated substrate was immersed in an aqueous solution of hydrochloric acid of 1 mol/l and aniline of 1 mol/l, with a gold-coated glass electrode as a counter electrode, and Q, 6
A black composite film was obtained by electrolytically polymerizing aniline by the amount of charge t00/♂ at a potential of v. After polymerization, the composite film with electrodes was immersed in warm water for 5 hours to remove polyvinyl alcohol. When the surface of the film after extraction was observed using a scanning electron microscope, irregularities of 1 to 2 μm in diameter were observed on the surface. The conductive polymer electrode obtained in the present invention was immersed in acetonitrile containing 1 mol/l of tetraethelammonium chloride, and doping/undoping with chlorine ions was repeated. Even after repeating doping/undoping more than 1000 times, the film did not peel off from the metal electrode. Dogue'g1m obtained a value 124 larger than that of a polyaniline film prepared under the same polymerization conditions (potential: (L6V, charge amount = taa/, ri) using the same electrode not coated with an insulating film.

[Effects of Invention 1] As explained above, according to the present invention, an electrolytic polymer of an aromatic compound is electrochemically composited into two laminated polymer films, and the upper layer of the obtained composite film is By extracting and removing only the polymer film, a conductive electrode material that is more porous, has a higher ion diffusion rate, and has higher electrode adhesion than K can be obtained. This film can be used to create polymer electrodes with various structures depending on the material, and has industrial applications as an electrode material for batteries and electrodes for electrochromic devices.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of the conductive polymer electrode material of the present invention.

Claims (1)

[Claims] 1. After forming an electrolytic polymer of an aromatic compound in two types of insulating polymer films coated on an electrode, only the upper insulating polymer film is extracted and removed. A conductive polymer electrode material characterized in that it is a material that can be used as a conductive polymer. 2. A step of coating a lower insulating polymer film on the electrode, a step of coating an upper insulating polymer film thereon, and electrolytic polymerization of an aromatic compound on the electrode substrate with the film to form the aromatic compound. A conductive polymer characterized by comprising the steps of: combining a polymer of a group compound into the lower and upper polymer films; and extracting and removing only the upper polymer film from the composite film. Method for manufacturing electrode materials.