JPH0422013A - Manufacture of complex material - Google Patents

Abstract

PURPOSE:To obtain a complex material that has no peeling off or falling off at the end by preliminarily molding a flexible conductive sheet material into the shape that can be built in an apparatus, by coating the surface and end part of a functional face to be coated with a conductive polymer of molding conductive sheet, with the conductive high polymer in a continuous mode. CONSTITUTION:A flexible conductive sheet material is preliminarily molded into the shape that can be built in an apparatus, and the surface as well as the end of a functional face to be coated with a conductive high polymer of a molding conductive sheet, is coated with the conductive high polymer in a continuous mode. The conductive sheet to be coated with the conductive high polymer must be preliminarily molded through the process of cutting and so on into the shape utilized for an apparatus to which it is to be used. A complex material can be obtained in such a form that is virtually ready for final use, and the process such as cutting, etc., for final shape which can cause damage such as the peeling off or falling off of the coating is omitted. The peeling off or falling off of the coating in use can thus be prevented, and a complex material of high reliability can be obtained.

Description

Detailed Description of the Invention [Industrial Fields of Application] The present invention relates to composites in which a conductive sheet formed into a shape for use in equipment is coated with a conductive polymer, particularly for battery electrodes, electromagnetic The present invention relates to a method for producing a composite useful as a shielding material and a capacitor electrode.

[Prior Art] When a composite consisting of a conductive sheet material and a conductive polymer is used as an electrode for a device such as a battery, the electrode is manufactured by first processing a large conductive sheet material. For example, the composite is coated with a conductive polymer by a method such as electrolytic polymerization, and then the composite is cut and molded into a shape for a battery electrode, and then incorporated into a battery. However, when cutting out a large number of composites from this large sheet, there was a problem in that the coated conductive polymer was damaged and the product yield was reduced. Also, at this time, due to processing, the ends of the composite are in a state where no conductive polymer exists (
(See Figure 8), flexible batteries such as vapor batteries may be subject to deformation such as bending during use.
Depending on the situation, the conductive polymer may peel off or be missing at the ends of the composite (electrode), making it impossible to exhibit stable battery characteristics over a long period of time.

[Problems to be Solved by the Invention] In view of these circumstances, the present invention provides a composite consisting of a conductive sheet coated with a conductive polymer material, which
It is an object of the present invention to provide a highly reliable method for manufacturing a composite that does not peel or fall off at its ends even when subjected to deformation.

[Means for Solving the Problems] As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have determined that the shape of the composite body when it is incorporated into a device is not limited to only the functional aspects of the composite body. First, it was discovered that it is important that the ends are also coated with a conductive polymer material, leading to the present invention.

That is, the present invention provides a method for producing a composite in which a flexible conductive sheet material is coated with a conductive polymer, in which the flexible conductive sheet material is previously molded into a shape to be incorporated into a device, and the molded conductive sheet is This is a method for manufacturing a composite, in which the functional surface and the end portions of the functional surface coated with the conductive polymer are continuously coated with the conductive polymer.

The most important thing in the method for manufacturing the composite of the present invention is that the conductive sheet covered with the conductive polymer is pre-shaped by processing such as cutting into a shape for use in the intended device. It is. That is, after being coated according to the present invention, the composite is not subjected to processing such as cutting from a large-sized composite to a large number of small composites suitable for each usage type as in the past.
They can be incorporated into equipment and used in their original shape or with only partial shape adjustment.

Therefore, the composite made according to the present invention does not require processing such as cutting of the entire circumferential surface of the composite that would damage the coated surface.

In the present invention, the composite in which the ends of the sheet-like conductor are also coated with a conductive polymer is the one shown in the plan view of FIG. 1 and the cross section of FIG. At the end of the sheet, it appears that the conductive polymer, which is a composite material, is connected to the front and back surfaces of the sheet by coating. According to this configuration, compared to the configuration shown in FIG. 8, the composite part (adhesive part) of the conductive polymer and sheet-like conductor is not fully exposed at the end, so the composite part as described above is not exposed. Bending stress will not be concentrated on defects (such as minute cracks). Furthermore, since the composite portion at the end is covered with a conductive polymer, the stress generated at the end due to bending can be alleviated to some extent within the conductive polymer compared to the structure shown in FIG. For this reason, by covering the entire end of the sheet-like conductor with a conductive polymer, it is possible to prevent the conductive polymer from peeling off or falling off from the sheet-like conductor, thereby increasing the flexibility of the composite. It becomes possible to improve the The ratio of the end portion of the sheet-like conductor covered with the conductive polymer is most preferably 100%.
It is. However, although the lower limit can be made smaller depending on the bending conditions during use of the composite and the method of covering the edges, the coverage rate cannot be uniformly determined. That is, what percentage of coverage is required to achieve the objective is determined by the quality of the composite material, the method of composite, the curvature of the composite during use, the position of the coating, etc.

For example, even with the same coverage rate of 50%, the coating methods shown in Figures 3 and 4 are possible, and in the case of usage where the same curvature is applied to the entire composite, the method shown in Figure 3 is better. More peeling,
Less likely to fall off.

Even the coating method shown in FIG. 4 may be usable if different curvatures occur depending on the part of the composite. In other words, when using a spirally wound composite as shown in Fig. 9, the covered part A in Fig. 4 is used for the center part, which has a higher curvature, and the outer periphery part, which has a lower curvature, is used. One possibility is to place the uncovered portion of B.

Furthermore, the lower limit of the coverage will vary depending on the material, thickness, flexibility, and method of combining the materials to be composited.

Examples of the conductive sheet material used in the present invention include metal sheets such as Ni, Pt, Au, and A1, alloy sheets such as stainless steel, and conductive polymer films with high conductivity and mechanical strength such as polypyrrole. Or conductive sheets made by uniformly mixing carbon fibers or carbon powder with resin, or forming Au onto plastic films, etc.
, Pt, metals such as Ni5A1, SnO2, In2O: +
A film made by vapor-depositing or coating a metal oxide such as ITO1 carbon material, etc. to make it conductive, or a plastic film such as a polyester film coated with polypyrrole by oxidative polymerization is used.

However, the electrical conductivity is usually 10' S cm-'
If it is above, there are no particular restrictions or additions,
It is selected as appropriate depending on what kind of device the composite is to be applied to. For example, when considering the application of the composite as a battery positive electrode, the conductive sheet material is preferably metal, and the redox potential of the polymeric material serving as the active material is higher than the redox potential of the conductive sheet material. It is preferable to select a material combination that has a negative potential. When considering the application of conductive polymers to capacitors, it is common to use Al.

Through holes can also be formed in the conductive sheet material used in the present invention. By providing through-holes in the conductive composite sheet, the polymer material composited with the sheet conductor is bonded through the through-holes, improving the adhesion between the conductive sheet material and the conductive polymer, and preventing the polymer from peeling off when bent. , can prevent falling off. Furthermore, since a good electrical connection can be achieved due to improved adhesion (reduced interfacial impedance), it becomes possible to efficiently inject and extract charges from the polymer material. The size of the through hole provided in the conductive sheet material varies depending on the material used in the composite and the method of use, and cannot be determined unconditionally. More preferably, it is 500 to 1200 μm. If it is less than 100 μm, the degree of adhesion between the conductive polymers will be low and sufficient strength will not be obtained. ratio), the strength of the sheet-like conductor itself becomes low. As for the percentage of through-holes, C can be changed depending on the materials used in the composite and how they are used, and is not determined by law. Taking the example of the positive electrode mentioned above, it is a sheet-like conductive material. The total area of the pores is 5 to 50% of the total area of the body, more preferably 10 to 30%.
% is desirable. If it is less than 5%, the degree of adhesion between the conductive polymers is low, and the effect of peeling resistance against bending and falling off is small. If it is 50% or more, the mechanical strength of the sheet-like conductor itself tends to decrease.

The shape of the through hole is not particularly limited, but when the composite is used as an electric element, it is preferably a shape that avoids concentration of electric field. That is, it has a rounded shape with no corners. The through-holes may be arranged in a regular pattern such as a lattice pattern or a staggered pattern, or randomly arranged, but it is usually preferable to arrange them regularly.

Further, it is more preferable that the sheet-like conductor not only have through holes but also have a roughened surface. The rough surface has microscopic irregularities that do not penetrate through the surface, and the irregularities may have a non-sharp shape to avoid concentration of the electric field. This surface roughening can be carried out using emery paper, an abrasive, mechanical polishing using a polishing machine, ion sputtering, electrochemical methods such as electric field etching, etc.

Among these, the blasting method and the electric field etching method are easy and reliable and are considered preferable. By roughening the surface of the sheet-like conductor, the polymer material covers the unevenness of the surface, which improves the adhesion between the sheet-like conductor and the conductive polymer, preventing it from peeling off or falling off. It will be strong against. Furthermore, since the contact area becomes larger, electrical connection becomes better, and it becomes possible to efficiently inject and extract charges from the polymer material.

Either the through hole or the rough surface may be processed first. When using a composite of a base material and a conductive material, or a metal coated with a conductive polymer material, as a sheet-like conductor, a through hole and a rough surface are formed in the base material in advance, and the conductive material is vapor-deposited and coated there. Alternatively, they can be combined by electrolysis, chemical polymerization, or the like.

Examples of the polymer materials used in the composite of the present invention include polymers of five-membered heterocyclic compounds containing monomers such as virol and thiophene, and polymers of aromatic hydrocarbon compounds containing monomers such as benzene and azulene. An amine compound polymer containing monomers such as aniline, diphenylbenzidine, etc. can be used. As a method for polymerizing the monomer, a chemical polymerization method using an oxidizing agent or an electrolytic polymerization method using electrical energy can be used.

The chemical polymerization method is carried out by adding an oxidizing agent to a solution containing monomers to oxidize the monomers. Examples of oxidizing agents include halogens such as iodine, sulfuric acid, and fluorine iodide; arsenic pentafluoride, antimony pentafluoride, silicon fluoride,
Metal halides such as phosphorous pentachloride; protic acids such as sulfuric acid, fluorosulfuric acid, and chlorosulfuric acid; oxygenated compounds such as sulfur trioxide, nitrogen dioxide, potassium permanganate, and potassium dichromate - sodium persulfate, persulfate Persulfates such as potassium and ammonium persulfate; hydrogen peroxide,
Oxidizing agents such as peroxides such as peracetic acid and difluorosulfonyl peroxide may be used. In the chemical polymerization method, when a polymer with a high degree of polymerization is synthesized, the polymer is insoluble and synthesized in the form of a powder. Therefore, in order to implement the composite of the present invention, it is necessary to mechanically bring the sheet-like conductor and the polymer into close contact, but this method has poor adhesion between the sheet-like conductor and the polymer material, resulting in a low interfacial impedance. It has the disadvantage of being expensive. On the other hand, in the electrolytic polymerization method that utilizes electrochemical reactions, by using a sheet-like conductor as a reaction electrode, a sheet-like conductor-polymer material composite can be produced in virtually one step. Polymerization also progresses on the end surfaces of the sheet-like conductor, which has the advantage that the end surfaces are naturally coated with a conductive polymer. Furthermore, polymerization and compounding of the polymer to the sheet-like conductor progresses at the same time.
The adhesion between the polymer and the sheet-like conductor is improved, and peeling and falling off due to bending can be suppressed. Furthermore, the improved adhesion also lowers the interfacial impedance, making it easier to inject and extract charges from the conductive polymer when the composite is used as an electric element. Therefore, when both chemical polymerization and electrolytic polymerization can be used to produce the composite of the present invention, it is considered that electrolytic polymerization is preferable to chemical polymerization.

Electropolymerization methods are generally described, for example, in J.

Electrochea+, Soc,, Vol, 13
0. No. 7, 1506-1509 (1983), El
ectochem, Acta, Vol. 27. No
, 1. [il~65 (1982), J. Chem.
Soc, Chem, Conunun, 11.99~
(1984), etc., a monomer and an electrolyte dissolved in a solvent are placed in a designated electrolytic bath, electrodes are immersed, and an electrolytic polymerization reaction is caused by anodic oxidation or cathodic reduction. be able to.

As the electrolyte, for example, as an anion, BF4-
ASF6- SbF6″″ PF&ClO4-H3O
4-5O42″″ and aromatic sulfonic acid anion are also cations H″ quaternary ammonium cation,
Examples include, but are not limited to, lithium, sodium, and potassium.

Examples of the solvent include water, acetonitrile, benzonitrile, propylene carbonate, γ-butyrolactone, dichloromethane, dioxane, dimethylformamide, and nitro solvents such as nitromethane, nitroethane, nitropropane, and nitrobenzene. , but is not particularly limited to these. Electrolytic polymerization can be carried out by constant voltage electrolysis, constant current electrolysis, or constant potential electrolysis.

Next, a battery using a composite of a sheet-like conductor and a conductive polymer material as an electrode will be described. The battery of the present invention basically consists of a positive electrode, a negative electrode, and an electrolyte, and a separator may be provided between the electrodes. The electrolytic solution is composed of a solvent and an electrolyte, but it is also possible to use a solid electrolyte. As mentioned above, the advantage of using the composite of the present invention as a battery is that the polymer is less likely to fall off or peel off when the electrode (composite) is bent, which prevents a decrease in capacity and an increase in interfacial impedance. This improves the reliability of the electrode, and since the exposed portion of the sheet conductor on the end face is reduced, leakage current (current that does not involve energy storage) during charging can be reduced, and self-discharge is also reduced. It is possible to make it smaller. As a result, it is possible to improve energy efficiency and energy capacity. Furthermore, the conductive polymer swells during the doping and dedoping process.
Since it has the characteristic of repeatedly shrinking, if the end of the sheet-like conductor is exposed, stress due to swelling and shrinkage will be generated at the end, and the polymer will easily peel off. This drawback can be easily avoided by coating the ends with a conductive polymer as in the present invention. In addition, by roughening the surface of the sheet-like conductor (current collector) and/or providing through holes, bonding between the front and back polymers and an increase in the contact area between the sheet-like conductor and the polymer occur. As a result, it is possible to prevent the polymer from peeling off or falling off when the composite is bent, and it is also possible to keep the interfacial impedance low. Furthermore, if an electrolytic polymerization method is used as a method for producing the composite, further improvement in properties can be expected. The composite of the present invention can be considered as a sheet-like electrode, and there are no restrictions on how it can be used as a battery electrode. It is expected that it will be effective as an electrode for spiral mounting (the electrode is rolled into a thin spiral) or for flexible sheet batteries.

The battery of the present invention is doped with anions or cations to store energy and dedoped to release energy through an external circuit. Furthermore, in the battery of the present invention, this doping-dedoping is performed reversibly, so it can be used as a secondary battery.

In the present invention, the composite of the sheet-like conductor and conductive polymer material of the present invention is used at least for the positive electrode.

Examples of dopants for polymer electrodes include the following anions and cations.A conductive polymer complex doped with a cation is an n-type material, and a conductive polymer complex doped with an anion is an n-type material. Provides p-type material. Can p-type material be used for the positive electrode and n-type material for the negative electrode?
Polyaniline is also suitable for the positive electrode because it becomes a stable p-type material when doped with anions.

(1) Anion: PF6″″ 5bF6AsF6 5
halide anions of group Va elements such as bC16-; halide anions of group Ia elements such as BF4-'', perchlorate anions such as ClO4, or sulfonate ions such as CFzSO3-.

(2) Cation: Alkali metal ion such as Li"Na"K", (R4N) [R: hydrocarbon group having 1 to 20 carbon atoms], etc.

Specific examples of compounds providing the above dopant include Teha, L
iPF5, LiSbF6, LiAsF6, LiC10<, NaClO4, Kl, K
PF6, KSbFb, KAsF6, KClO4, [(n
-Bu)4N] "ASF6[(n -Bu)
< N co-CI O4-, LiCP
Examples include zSO3, LiAlC1<, and LiBF4, which are used as electrolytes for batteries.

As the solvent for the battery electrolyte, it is preferable to use a so-called polar apronto solvent, which is an apronto solvent and has a large dielectric constant. Specifically, for example, ketones, nitriles, esters (lactones), ethers, carbonates,
A nitro compound, a sulfolane compound, or a mixed solvent thereof can be used, and among these, nitriles, carbonates, and sulfolane compounds are preferred. Typical examples include acetonitrile, propionitrile, butyronitrile, valeronitrile, benzonitrile, ethylene carbonate, propylene carbonate, γ-butyrolactone, sulfolane, 3-methylsulfolane, tetrahydrofuran, 2-methyltetrahydrofuran, and the like.

It is also possible to add polymers to these electrolytes to make them into a paste and improve processability.

In addition to the above-mentioned polymeric materials, the negative electrode in the battery of the present invention includes LiSZ n s Cu SA g, Al5A
l-Li binary alloy, Li-Al-Mg.

Metals and alloys such as Li-Al-Mn ternary alloy, Wood alloy, etc. can also be used.

In this case, when the metal itself has a current collecting function with the active material, when the current collecting material such as l'J l-, A1, etc. is used in close contact with the active material, or when the active material is connected to the electrolyte by using a current collector. In some cases, it is supplied by precipitation of cations.

When using a current collector, it is preferable that the ends of the current collector are covered with an active material.

As the separator, one is used that has low resistance to ion movement of the electrolyte solution and has excellent solution retention properties. For example, glass fiber filter; polyester, Teflon, polyflon 1. A polymer bore filter such as polypropylene, a nonwoven fabric; or a nonwoven fabric made of glass fiber and these polymers can be used.

Further, a solid electrolyte can be used as a component in place of the electrolyte and the separator.

For example, in inorganic systems, AgC1, AgBr, AgI,
Metal halides such as Li1, RbAg4I5, Rb
Examples include Ag+ I4 CN. In addition, in organic systems, polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, polyacrylonitrile, etc. are used as a polymer matrix, and composites in which the electrolyte salt mentioned above is dissolved in the polymer matrix, or crosslinked products of these, and low molecular weight polyethylene oxide are used. Examples include polymer electrolytes in which ionic dissociative groups such as , polyethyleneimine, and crown ether are grafted onto the polymer main chain.

[Example] The present invention will be explained in more detail with reference to Examples below.

Example 1 Staggered through holes with a diameter of 0.9n+mφ and a pitch of 1.8) were provided in a 4×30cm, 20μm thick SUS foil, and emery particles No. 200, Ikg/c+n 2
An electrode was prepared that was blasted at a pressure of . An aqueous solution containing 0.75M aniline and 3.0M HB F-14 was prepared as a polymerization solution, and a SUS plate was used as a counter electrode.

The electrode was immersed in the polymerization solution so that the effective polymerization area was 4×25 cm, and polyaniline was composited on both sides of the SUS foil at a current density of 3 mA/cm′.

After polymerization, the post-coalescence was left in running water for 12 hours, and then 0.3ML
Washing was repeated in iBF4/γ-butyllactone solution. After leaving this in running water for 2 hours, O.1M HB
Fully dedoped to a potential of -0.4V vsS CH in FJ, 20vol 1% hydrazine 1-permanent -M
e After being immersed in an OH solution overnight, vacuum drying was performed at 80° C. for 5 hours. The thickness of the prepared composite is approximately 1200 μm
The weight of 1 polyaniline was approximately 2 g. This composite was compressed to a thickness of 400 μm. The shape of the composite was as shown in Figure 5, and all parts except B were covered with polyaniline and SUS foil. This composite was wound once in a spiral with part A as the center of the winding, and when it was opened, there was no part where the SUS foil and the composite had separated.

Comparative Example 1 Same as Example 1 except that the ends C and D of 5US foil were masked with fluororesin adhesive tape as shown in Figure 6, and polymerization was carried out using an electrode with a width of 4 cm from the exposed metal surface. A composite was prepared in the same manner (the mask part was cut out last). The winding was tightened in the same way as in Example 1, and when it was opened, it was found that the polyaniline had peeled off from the SUS foil in the parts C and D near the center of the winding (parts with high curvature).

Example 2 The SUS foil of Example 1 was made with a square hole in the B part as shown in Figure 7, and the end face of the B part was made of polyaniline with 80 mm
Processed to cover more than %. A composite was produced in the same manner as in Example 1 except that this SUS foil was used as an electrode.

After cutting off the unpolymerized SO5 part from part B, wrapping it around part B and opening it, it was found that the SUS foil and polyaniline in part B had not peeled off.

Example 3 The composite of Example 1 was cut out at a length of 20 cm from point A, and SUS foil terminals were attached. This was used as a positive electrode and as a negative electrode with a thickness of 80 μm (4 cm width).
), using polypropylene (Daicel Chemical Industries: Celguard #3401) as a separator, start winding so that the center of the winding is at part A (Fig. 9), and the inner size is 13.6a + mφ, height (inner dimension). It was mounted inside a 47.2 mm cylinder.

After injecting an electrolytic solution in which 4 mo I/kg of solvent LiAsF6 was dissolved in ethylene carbonate, 2-methyltetrahydrofuran:dimethoxyethane-8:8:5 (volume ratio), the voltage was 2.5 to 3.7 V1 ± 30 mA.
When charging and discharging was performed, the 10th capacity was 1411n.
The performance was 93 mAh/g (polyaniline).

Example 4 The SUS foil portion was cut out from part B of the composite of Example 1 and a SUS foil terminal was attached. Using this as a positive electrode, a negative electrode made of the same material as in Example 5, a separator, and propylene carbonate as an electrolyte; dimethoxyethane-7=3 (volume ratio), LiBF of 3a+l151
A flexible sheet type battery as shown in FIG. 10 was fabricated using an electrolytic solution in which + was dissolved. The exterior material is a heat-melting plastic film with an aluminum core. When charging and discharging were performed at 2.5 to 3.7 V and ±30 mA, the capacity at the fifth time was 189IIIAh. After that, this sheet-type battery was wound around a rod with a diameter of 1c+a so that the part A was in the center, and then stretched out and charged and discharged, resulting in a capacity of 173mAh.

Comparative Example 2 When the electrode of Comparative Example 1 was subjected to a charge/discharge test under the same conditions as in Example 4, it was 173 mAh on the 5th time and 14 mAh after winding.
It dropped to 6mAh.

[Effects of the Invention] As explained above, according to the present invention, it is possible to obtain a composite in substantially the final use shape, and therefore, unlike the conventional method, there is no need to avoid the final use, which may cause damage such as peeling or falling off of the coating. Processing such as cutting into shapes is no longer necessary, which improves yield and productivity. The obtained composite also has excellent durability against bending deformation, and can prevent the coating from peeling off or falling off during use, thereby improving the reliability of equipment incorporating the composite.

[Brief explanation of drawings]

FIG. 1 is a plan view illustrating an example of a composite obtained by the present invention, FIG. 2 is an enlarged cross-sectional view taken along line X-X in FIG. 1, and FIGS. 3 and 4 are composites obtained by the present invention. FIG. 5 is a plan view illustrating the details of the present invention obtained in Example 1, and FIG. 6 is a plan view illustrating the electrode used in Comparative Example 1. , FIG. 7 is a plan view illustrating the electrode used in Example 2, FIG. 8 is a diagram illustrating the configuration of a conventional composite (electrode), and FIG. 9 is a diagram illustrating the configuration of the battery in Example 3. Figure, 10th
The figure is a diagram illustrating the configuration of a battery of Example 11.

Claims (1)

[Claims] In a method for producing a composite in which a flexible conductive sheet material is coated with a conductive polymer, the flexible conductive sheet material is molded in advance into a shape to be incorporated into a device, and the conductive polymer of the molded conductive sheet is coated with a conductive polymer. 1. A method for producing a composite, comprising continuously coating the functional surface and the end thereof with a conductive polymer.