JPS62268057A - Secondary battery - Google Patents

Abstract

PURPOSE:To secure such an electrode that is excellent in shelf life and enhances the extent of battery performance, by processing a base material whose one side is hydrophobic, with an oxidant, making only one side of the base material hold this oxidant, and superposing a compound having conjugated double bond on the base material under a vapor-phase ambience. CONSTITUTION:An Fe (ClO4)3 component is held on one side of a hydrophobic, polyethylene-make porous film, by way of example, and it is made contact with pyrrolic steam, forming polypyrrole, and it is dried by air, thus such a film that is flexible and conductive, whose one side is black, is secured. And, such one that is punched out into the specified size is set down to a positive electrode 1, while lithium is set down to a negative electrode 2, and an electrolyte made up of dissolving LiBF4 into propylene carbonate is used, thus a battery is secured. This conductive material is excellent in resistance to oxidation so that it is in no case subjected to oxidizing degradation by oxygen and moisture in the air and, what is more, shelf life in the electrode itself is very good. Therefore, conversion and decomposition are not caused by the presence of oxygen and moisture inside the battery or overcharge and so on.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a secondary battery using a conductive material having a conductive polymer on either side of a specific base material as an electrode material. I'll go.

<Prior Art> In recent years, secondary batteries using conductive polymers made of various organic materials as electrode materials have been proposed.

The conductive polymer that serves as the electrode material for this type of secondary battery usually has little electrical conductivity, but it can be doped and undoped with dopants such as various anions and cations. The treatment dramatically increases the conductivity. Then, a conductive polymer doped with anions is used as a positive electrode material, a conductive polymer doped with cations is used as a negative electrode material, and the solution containing the dopant is used as an electrolytic solution, and doping and and- By electrochemically and reversibly performing pinging, a chargeable and dischargeable battery is constructed.

As such conductive polymers, polymers having co-19 double bonds in the main chain, such as polyacetylene, polyparaphenylene, polythenylene, polypyrrole, polyaniline, and polyparaphenylenevinylene, are conventionally known. For example, polyacetylene is used as the electrode material for at least one of the positive electrode and the negative electrode, and BF-1CJO-1SbF6-1P "7-ions such as 6-, or Li+, Na, R4-N CR represents an alkyl group", etc. A configuration is adopted in which cations are electrochemically and reversibly doped and undoped.

By the way, such conductive polymers are in powder form.

Granular, lumpy or film-like particles are classified as 18, but powder-like 2
In the case of granular or lumpy conductive polymers, when they are used as electrode materials to construct non-aqueous electrolyte secondary batteries or solid electrolyte secondary batteries, they may be used alone or with appropriate additives to improve conductivity. After adding a conductive material and/or a thermoplastic resin to increase the mechanical strength of the electrode, it is time-consuming to pressure-form the electrode into the shape of the electrode. On the other hand, in the case of conductive polymer films,
It has the advantage that it is relatively easy to manufacture electrodes because it can be made into electrodes simply by shaping them into electrode dimensions.

The above-mentioned conductive polymer films include polyacetylene films obtained by blowing acetylene gas onto a glass wall coated with a polymerization catalyst and then peeling from the glass wall, and polyacetylene films obtained by electrochemical oxidation reaction (electrolytic oxidation polymerization).
A polythenylene film or a polypyrrole film obtained by forming it on an electrolytic electrode and then peeling it off from this electrode, or a solution containing an oxidizing agent and a polymer binder is coated on a base material such as a PET film to form a polythenylene film or a polypyrrole film obtained by peeling it off from the electrode. A single layer of a film-like conductive polymer is formed on a substrate by contacting the vapor with the conductive polymer (a conductive composite film is known).

<Problems to be Solved by the Invention> However, when a secondary battery is constructed by using the above-mentioned conventional conductive polymer film as a battery electrode material, the presence of minute amounts of oxygen and moisture in the battery with the polyacetylene film This has the disadvantage that the performance of the electrode deteriorates as the polymer deteriorates during cycling, and the cycle life is significantly shortened due to a sudden increase in charging voltage and a decrease in charging/discharging efficiency during cycling. There have been problems such as the fact that the electrode fabrication work is difficult and complicated because it is easily oxidized, and the electrode has poor storage stability because the material deteriorates significantly due to oxidation.

In addition, for polythenylene films and polypyrrole films produced by electrochemical oxidative polymerization reactions, the size of the film is regulated by the size of the electrolytic electrode, and the manufacturing method is complicated and requires specific manufacturing equipment. This causes high battery costs. Furthermore, since it is difficult to obtain a thick and uniform film, when this film is used as a battery electrode in combination with a current collector, contact with the current collector may deteriorate during charge/discharge cycles, and the battery reaction may deteriorate. There was a problem in that since it is concentrated in a part of the electrode, it tends to cause deterioration of battery performance.

Furthermore, in the case of the above-mentioned conductive composite film, since a polymer binder is used to hold the oxidizing agent on the substrate, the conductive polymer 1q removed after the polymerization reaction is combined with the pyrrole or aniline polymer. It becomes a composite conductor mixed with a polymer binder. For this reason, the concentration of the conductive polymer such as pyrrole aniline in the conductive polymer decreases, and when this is used as an electrode material, compared to, for example, when using the conventional conductive polymer film mentioned above, Even if an attempt is made to achieve the same performance, there is a problem in that the polymer concentration is reduced and the performance is inferior.

Therefore, the present inventors first applied for patent application No. 60-225761.
No. 1, in which a compound having a conjugated double bond is polymerized in the gas phase on a base material having a space capable of holding the oxidizing agent in the presence of the oxidizing agent, and is formed into any shape, especially a film shape. A novel conductive material without the above-mentioned drawbacks was obtained, and in Japanese Patent Application No. 60-260923, it was proposed to use this conductive material as an electrode material for secondary batteries.

However, in the conductive material of the above-mentioned Japanese Patent Application No. 60-225761, when an oxidizing agent is to be held on only one side of a planar base material in order to form a single layer of conductive polymer on one side of the base material, the oxidizing agent is Since the oxidizing agent easily penetrates into the entire space of the base material and is retained, the oxidizing agent also permeates other surfaces of the base material, and after the above-mentioned gas phase polymerization, a conductive polymer is generated over the entire base material, and as a result, only one side of the base material is formed. It turns out that it is very difficult to produce conductive polymers.

Therefore, when using the above-mentioned conductive material as at least one of the positive electrode and the negative electrode, as in the case where the above-mentioned conventional conductive polymer film is used as the electrode material, make sure that the two electrodes do not come into direct contact between the opposing electrodes. It is necessary to place a diaphragm (separator) such as a non-woven fabric, or to place a current collector in close contact between the electrode and the battery can, when assembling the battery. Another drawback is that it requires a process of carefully and tightly pasting the current collector together.

Means for Solving the Problems〉 The present inventors conducted research to solve the above problems, and found that a plugging material having a space capable of retaining an oxidizing agent and having at least one surface that is hydrophobic can be used as an oxidizing agent. to retain the oxidizing agent only on either side of the base material, polymerize a compound having a conjugated double bond on the base material in a gas phase atmosphere, and apply the compound to either side of the base material. It has been found that the desired purpose can be achieved when a conductive material formed by forming a polymer of 1q is used as W2N for at least one of the positive electrode and the negative electrode.

The above-mentioned oxidizing agent is a compound that has polymerization activity toward a compound having a conjugated double bond, and can be used alone or in combination.
Used in combination of more than one type. Usually, metal salts and peroxides having strong acid residues such as halogen and cyan are used. Specifically, Fe (CJ204 > 3, Fe (B
F4)3.

Fe2 (S i F6 )3, Cu (C!2.
04)2.

Cu (BF4)2, cus! F6, FeCJ
23°CuC,22,K3 (Fe(CN)6).

RuCf! , 3, MOC, 25, WCl2.6.

(NH4)2S208. 2S208゜xa S
O, NaBO3, Town 02. etc., and those having water of crystallization or those that can be used as an aqueous solution can also be used.

Further, the base material used has a space for holding the oxidizing agent as described above, and has at least one surface that is hydrophobic. Hydrophobicity is defined as having a water contact angle of 90' or more. The oxidizing agent is used as an aqueous solution so that it is easily retained on only one side of the substrate. When organic solvents such as methanol, ethanol, acetonitrile, and tetrahydrofuran are used as solvents for oxidizing agents, they penetrate into the substrate.
Even if one surface of the substrate is hydrophobic, the oxidizing agent easily permeates into that surface, so it is difficult to retain the oxidizing agent only on one surface of the substrate. For example, if one side of the sheet-like base material is hydrophobic and the other side is hydrophilic, the base material may be immersed in an oxidizing agent aqueous solution, or the oxidizing agent aqueous solution may be applied to the hydrophilic side. The oxidizing agent can be easily retained on the hydrophilic surface of the substrate. Further, when both surfaces of the sheet-like base material are hydrophobic, the oxidizing agent can be retained on one surface by repeatedly applying an oxidizing agent aqueous solution to one surface. Furthermore, if both sides of the sheet-like base material are hydrophilic, one side is treated with 1 g of a silicone-based, fluorine-based, etc. water agent to make it hydrophobic, and then immersed in an oxidizing agent aqueous solution, or the other side is hydrophilic. By applying an oxidizing agent aqueous solution to the surface, the oxidizing agent can be retained on this hydrophilic surface.

The space that can hold the oxidizing agent may have a spatial size that can hold the oxidizing agent used at least in the form of molecules or aggregates. It is not preferable if the space is too small to hold the oxidizing agent in a molecular state, or if the space is too large to hold the oxidizing agent in an aggregated state. This space is distributed on or inside the substrate as pores or gaps of various shapes. Specifically, in the case of pores, the size thereof is such that the average pore diameter is from o, ooi to 1t) O, um, preferably from 0.005 to 50 μm. Further, the depth of the pores is 0.00 μm or more, preferably 0.00 μm or more.
It is known that 1σ is greater than 0.005 μm.

For example, the shape of a planar base material having such characteristics is as follows:
Specifically, porous materials (plate-shaped molded products, films, filaments), woven fabrics.

Mixed with non-woven fabrics, etc.

In addition, as the base material, arborescent or inorganic materials are used.

The most suitable organic base materials are polyolefin, polyhalogenated vinyl, and polyfluorine.

Polyester-based, polyamide-based, polyimide-based.

Materials such as polyvinyl alcohol-based, polyacrylic-based, polycarbonate-based, rayon-based, cellulose-based, copolymers thereof, and mixed material systems are used. In addition, as the inorganic base material, carbonaceous type, metal type 1 alloy type,
Metal oxides, metal carbides, metal nitrides, and mixtures thereof are used. Furthermore, a mixed base material of an organic base material and an inorganic base material may also be used.

Specifically, such base materials include polyethylene, polypropylene, ethylene-propylene copolymer, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polytetrafluoroethylene, and polyethylene terephthalate. , polybutylene terephthalate, polystyrene, polyamide, polyimide, polyamideimide, polyvinyl alcohol.

Ethylene-vinyl acetate copolymer, polyacrylonitrile, polymethacrylonitrile.

Polymethyl methacrylate, polybutyl methacrylate, borostyrene-acrylonitrile, polycarbonate,
Rayon, methylcellulose, nitrocellulose, carboxymethylcellulose, activated carbon, carbon black,
Graphite, chromium.

Titanium, nickel, gold, platinum, tantalum, copper.

Silver, iron, stainless steel, alumina, wrinkle strength, silica alumina, zirconia, kaika berylli cum, potassium titanate, silicon carbide, boron carbide, titanium carbide, molybdenum carbide, tantalum carbide, boron nitride, silicon nitride,
Niobium nitride and the like are used.

The compounds having a co-IQ double bond used in the present invention include pyrrole compounds, thiophene compounds, etc. alone or in combination. Preferably, a pyrrole or thiophene compound having no substituents at the 2 or 5 positions of the ring structure of pyrrole or thiophene is used. Specific examples of pyrrole compounds include pyrrole, N-methylpyrrole, N-ethylpyrrole, and N-n-propylpyrrole.

\-n-butylpyrrole, N-phenylpyrrole, N-
Toluylpyrrole, N-naphthylpyrrole, 3-methylpyrrole, 3,5-dimethylpyrrole, 3-ethylpyrrole, 3-n-propylpyrrole, 3-n-butylpyrrole, 3-phenylpyrrole, 3-toluylpyrrole,
3-pufthylpyrrole, 3-methoxypyrrole, 3-5
-dimethoxypyrrole, 3-ethoxypyrrole.

-l, 3-n-probogycypyrrole, 3-phenoxypyrrole, 3-methylN-methylpyrrole, 3-methyl-xyN-methylpyrrole, 3-talolvirol, 3-bromopyrrole, 3-methylthiopyrrole, 3-methylthiopyrrole N-methylpyrrole and the like.

In addition, specific examples of thiophene-based compounds include 2,2-bithiophene, 3-methyl-2,2'-bithiophene, 3
, 3-dimethyl-2,2°-bithiophene, 3,4-dimethyl-242°-bithiophene.

3,4-dimethyl-3°,4゛-dimethyl-2,2゛-
Bithiophene, 3-methoxy-2,2'-bithiophene, 3,3'-dimethoxy-2,2-bithiophene.

2.2°,5',2°°-terthiophene, 3-methyl-2,2',5°,2°"-terthiophene, 3,3°
-dimethyl-2,2',5'',2'°-terthiophene, etc.

The ratio of the oxidizing agent to the compound having a conjugated double bond is related to the amount of polymer produced, but is usually 0.001 to io
, ooo times the mole, preferably 0.005 to 5,
000 moles.

Forming a polymer of a compound having a conjugated double bond on a substrate is carried out in a gas phase atmosphere.

That is, the polymer formation is performed in a gas phase atmosphere in the presence of vapor of only the compound having a conjugated double bond or with nitrogen, argon, air, other gases, or mixed gases. Although the entire system can be operated under elevated pressure, normal pressure, or reduced pressure, it is usually preferable to carry out the process under normal pressure from the viewpoint of process control.

The reaction temperature is not particularly defined as long as it is a temperature at which a compound having a conjugated double bond can polymerize, but it is usually -20 to
It is carried out at 150°C, preferably from 0 to 100°C. In addition, the reaction time is related to the reaction temperature, the amount of oxidizing agent, the mother of the compound having a conjugated double bond, etc., but is usually 0.01 to 2
00 hours, preferably 0.02 to 100 hours.

After the polymerization reaction, a dark brown to black homogeneous polymer is produced on the portion of the base material that retains the oxidizing agent.

Once formed, an oxidizing agent is further held on top of the above-mentioned polymer, and the polymerization reaction is continued by contacting with a compound having the same or different type of conjugated double bond to increase the number of polymer-forming groups or to increase the number of two or more types of polymer-forming groups. The production of polymers can be obtained.

After the polymerization reaction is completed, the compound having a conjugated double bond and the oxidizing agent remaining on the substrate are removed. Usually, it can be removed by immersing and washing the substrate in water, alcohol, or an organic solvent. Thereafter, the conductive material of the present invention can be obtained by drying the base material using a conventional drying method.

In the secondary battery of the present invention, there are cases in which electrodes made of such conductive materials are used for both positive and negative electrodes, and cases in which this electrode is used only for one electrode and metals, metal oxides, or other electrodes are used for the other electrodes. Further, known conductive polymers, organic compounds, and interline metal compounds other than the reaction products of the present invention may be used as electrode materials. For example, if an electrode using this conductive material is used only for the positive electrode and a metal is used as the negative electrode material, it is recommended to use a metal with an electronegativity of 1.6 or less as the negative electrode. Preferred examples of such metals include L1. Na, Mg.

/l or alloys thereof, and 1-i and li alloys are particularly preferred.

On the other hand, when the present invention is applied to a non-aqueous electrolyte secondary battery, the electrolyte used at that time is a solution in which an electrolyte is dissolved in an interline solvent. Examples of such electrolytes include salts with cations and anions such as metal cations and organic cations having an electronegativity of 1.6 or less. Examples of onium ions include quaternary ammonium ions, carbonium ions, oxonium ions, and the like. In addition, as an anion, BF-1C
,20-1PF6-1ASF-,CF3SO3-,
I-, 13r-10°C-1F-, and the like. Specific examples of such electrolytes include lithium tetrafluoroborate (LiBF4) and lithium perchlorate (L
iCλ04), lithium hexafluorophosphate (LiP
F6), lithium tetrachloroaluminate (LiAβC
β4), tetraedylammonium tetrafluoroborate ((C2H5)4NBF4), tetraethylammonium perchlorate ((C2H5)4NCbu04), lithium 1-lifluoromethanesulfonate (L! CF330)
3>, lithium iodide (LiI>, lithium bromide (
Examples include, but are not limited to, LiBr) and the like.

Then, using the conductive material of the present invention for both the positive and negative electrodes,
For example, if a battery is constructed using an electrolyte solution in which 4 is dissolved as an electrolyte, during charging, BF4- in the electrolyte is added to the conductive material in the positive electrode, and BF4- in the electrolyte is added to the conductive material in the negative electrode. Ll in each layer is doped. On the other hand, during discharge, BF4-Ll doped into the positive and negative electrodes is released into the electrolyte, respectively.

In addition, as the organic solvent for dissolving the electrolyte, it is preferable to use an aprotic one with a high dielectric constant, such as nitrile, carbonate, ether, nitro compound, amide, sulfur-containing compound,
Chlorinated hydrocarbons, ketones, esters, etc. can be used. Moreover, two or more kinds of such solvents can also be used in combination. Representative examples of these include acetonitrile, propionitrile, butyronitrile, benzonitrile, propylene carbonate, ethylene carbonate,
Tetrahydrofuran, dioxolane, 1,4-dioxane, nitromethane, N,N-dimethylformamide, dimethylsulfoxide, sulfolane, 1,2-dichloroethane, T-butyrolactone, 1,2-dimethoxyethane, methyl phosphate, ethyl phosphate, etc. These include, but are not limited to.

The concentration of the electrolytic solution of the present invention is usually o, ooi~
Used at 10 mol/β, preferably 0.1 to 3 mol/β
Used in λ.

In addition to being injected, such an electrolytic solution can also be used by impregnating an electrode made of the conductive material of the present invention in advance.

Moreover, in the present invention, a solid electrolyte can also be used instead of the above electrolyte solution. Such solid electrolytes include, for example, L;r, L;■-Abu203, Li3N, as a lithium conductive solid electrolyte.
LISICON, lithium ion conductive glass (for example, 2S-P2S5-Lil system, etc.), γ■-Li3P○
Lithium ion conductors with type 4 structure (e.g. L!
4 S! 04-L! 3 PO4 series, etc.), lithium ion conductive polymer electrolytes (for example, polyethylene oxide-LiCiQ04 series, etc.), and those with additives added thereto.

Moreover, although the above description has been made of a method of forming an electrode as is without subjecting the conductive material to doping treatment, it is also possible to dope the conductive material with a dopant in advance and then use it as an electrode.

Further, in the present invention, in order to fix the electrode in the electrolyte, the electrode may be covered with a slat-like or holed glass, Teflon, polyethylene, plate, or the like.

When the conductive material according to the present invention uses, for example, the above organic base material, the organic base material can also serve as a separator. Further, if a conductive material using an inorganic base material as described above is used, the base material can also be used as a current collector.

Further, for example, when the base material also serves as a current collector, a porous membrane such as glass filter paper, Teflon, polyethylene, polypropylene, or nylon may be used as the separator.

<Function> The above-mentioned conductive materials have excellent oxidation resistance and do not deteriorate due to oxidation due to oxygen or moisture in the air, making it easy to control the electrode manufacturing environment, and not only has a good shelf life of the electrode itself. The battery does not undergo denaturation or decomposition due to the presence of oxygen or moisture inside the battery or overcharging, and there is no sudden voltage increase during charging, making it possible to improve charging efficiency and cycle life.

In addition, this conductive material is obtained by polymerizing a compound having a conjugated double bond on a suitable base material in a gas phase atmosphere in the presence of an oxidizing agent, so it is easy to manufacture and relatively inexpensive. Not only that, even if the film is thick, a uniform thickness can be obtained, and an electrode material integrated with a separator or current collector can be easily obtained, so that the battery assembly process can be greatly simplified. Furthermore, when a porous material is used as the plugging material, there are advantages such as improvement in the liquid impregnation property (gold electrolyte property) of the electrode inner body and improvement in the charging and discharging efficiency of the battery.

<Example> The present invention will be specifically described below with reference to manufacturing examples of conductive materials and examples of secondary batteries according to the present invention.

Production Examples 1 to 3 of Conductive Materials A polyethylene porous film with a pore diameter of 0.1 to 10 μm and a film thickness of 20 μm and hydrophobic on both sides (height: 10 cm, width: 20 cm)
A Fe (CJ2c) -8H20-water saturated solution was applied three times to one side of the film to maintain the three Fe (C!;104) components uniformly on one side of the film. Then,
Pyrrole (4 m, l) was placed at the bottom of a glass container (depth 10 cm, width 25 cm, height 15 cm), the porous film obtained by the above treatment was suspended from the top of the glass container, and the top of the container was covered with a glass plate. It was sealed and exposed to pyrrole vapor.

Upon contact with pyrrole vapor, the porous film rapidly changed color from yellow to dark green to black, forming polypyrrole on one side of the porous film. After the predetermined contact time shown in Table 1, the film was removed and diluted with methanol for 3 hours.
The sample was immersed for Q minutes to extract and remove unreacted pyrrole and the three Fe (C104) components. After continuing this operation three times and air drying, 1 q of flexible film with black on one side was obtained.

Table 1 also shows the thickness of this film and the results of measuring the electrical conductivity in the horizontal direction on one side of the film by placing an electrode on one side of the film.

Table 1 Incidentally, the electrical conductivity was measured by a four-terminal method.

In addition, when we measured the electrical conductivity of the film in the vertical direction by placing electrodes on one side and the other, both values were less than 10-103 cm, indicating that we were able to make only one side conductive. It could be confirmed.

Manufacturing example of conductive material 4° Maximum pore diameter 0.02 x O, 2 μm, film thickness 25 μm, double-sided hydrophobic polypropylene porous membrane (Duraguard)
As a result, a glossy film having a thickness of 28 μm and black on one side was obtained.

The horizontal electrical conductivity of this film is 6,5 x 10-
2S Cm", and the vertical conductivity is 10"1
03 cm-1 or less, and only one side could be made conductive.

Manufacturing example 5 of conductive material: Surface hydrophilized with surfactant, film thickness 220 μm
, 30 pieces of polypropylene nonwoven fabric of 1875 mm2
% potassium hydroxide aqueous solution and heat-treated at a temperature of 60° C. for 1 hour, and then thoroughly washed with water and dried, the surfactant is removed and the surface of the cloth becomes hydrophobic.

Except for using this nonwoven fabric, the same procedure as in Production Example 2 above was carried out to hold three components of Fe (CaO2) on one side of the nonwoven fabric and to bring it into contact with pyrrole vapor. A nonwoven fabric with a film thickness of 230 μm and one side black was obtained. Ta. The electrical conductivity of this nonwoven fabric in the horizontal direction is 1.8X'IO'S Cm-1, and the electrical conductivity in the vertical direction is -to-1O8CIIl-1 or less, making only one side of the nonwoven fabric conductive. I was able to do that.

Comparative Production Example 1 of Conductive Materials The same process as in Production Example 5 above was carried out except that the treatment with 30% potassium hydroxide aqueous solution was not carried out. As a result, it was impossible to retain the oxidizing agent on only one side of the nonwoven fabric, and polypyrrole vapor was removed. Upon contact, polypyrrole was generated on both sides of the nonwoven fabric, resulting in a black color.

The electrical conductivity of this nonwoven fabric in the horizontal direction is 1.5×10'S
cm-', vertical S air conductivity 4.8x10'5c
m-1, and it was not possible to make only one side of the nonwoven fabric conductive.

Comparative Production Example 2 of Conductive Materials Same as Production Example 1 above, except that a 3.8 day 20 methanol saturated solution of Fe (C2O4) was used instead of a 3.8 day 20 water saturated solution of Fe(CflO4) as the oxidizing agent solution. As a result of carrying out the same procedure, a film was obtained in which both sides were blackened due to the formation of polypyrrole. The electrical conductivity of this film in the horizontal direction is 2.
8X 10-15cm, vertical direction is 1.8x 1
It was not possible to make only one side of the film conductive for 5 o-25 cm-1 cy.

Manufacturing example 6 of conductive material: pore diameter 0.1 to 1Qμm, film thickness 80. czm,! 1
On one side of a polyethylene porous film measuring 0 cm and 20 cm wide and hydrophobic on both sides, draw 40 straight lines with a width of 2 II 1 m in the vertical direction with a water saturated solution of FeCJ2.3 6H20.
After air drying, it was placed in a pyrrole vapor atmosphere in the same manner as in Production Example 1 above. As a result, 1q of films having 40 black straight lines with a width of 2 mm in the longitudinal direction on one side were formed. This film exhibited electrical conductivity of 1.3x 10-1S0-1S in the longitudinal direction, and insulating properties in the lateral and vertical directions.

In this way, it was possible to obtain a conductive film having conductivity only in the vertical direction on one side of the film.

Manufacturing example 7 of conductive material Using 3-methylpyrrole instead of pyrrole, Fe
(CJ204 > 3 ・Cu(BF4 instead of 8H20)
) A 40% aqueous solution of 2 was used in the same manner as in Production Example 1 above, and as a result, a film having a thickness of 22 μm and black on one side was obtained. The electrical conductivity of this film in the horizontal direction was 1,8x 1Q'3 cm-1, and the electrical conductivity in the vertical direction was less than 10-10-1 OS'.

Production Examples 8 to 14 of Conductive Materials Various pyrrole compounds and various oxidizing agents shown in Table 2 were present on one side of various porous films, and 2
The results of polymerization after 4 hours of contact are also shown in Table 2.

Manufacturing Examples 15 to 21 of Conductive Materials The results were shown in Table 3 in the same manner as Manufacturing Example 1 above, except that the various nonwoven fabrics shown in Table 3 were used.

In the case of Production Examples 16, 17, 18, and 20. 21, one side of each nonwoven fabric was spray-coated with a fluorine-based water repellent to make this one side hydrophobic, and then each nonwoven fabric was soaked in a saturated aqueous solution containing an oxidizing agent. The nonwoven fabric was dipped, and the oxidizing agent was retained on the surface that had not been made hydrophobic.

Production Examples 22 to 28 of Conductive Materials Table 4 also shows the results of production conducted in the same manner as in Production Example 1 above, except that various woven or nonwoven fabrics shown in Table 4 were used.

In addition, in these production examples, each woven fabric and non-woven fabric is treated by spraying a silicone-based water repellent on one side to make it hydrophobic, and then applying an oxidizing agent to the side that has not been made hydrophobic. and held it.

Manufacturing Example 29 of Conductive Material Table 5 shows the results of measuring changes over time in the electrical conductivity of the conductive film obtained in Manufacturing Example 2 above.

The results shown in Table 5 and above show that the change in electrical conductivity of the conductive film according to the present invention is extremely small.

Production example of conductive material 30 2,2'-bithiophene instead of pyrrole 5. The same procedure as in Conductive Material Production Example 3 was conducted except that OC1 was used and the reaction temperature was 70'C. As a result, 1q of porous films with one side black were obtained. The electrical conductivity of this film is 7.5X 10'SCm in the horizontal direction and 10-1 in the vertical direction.
A must-see again below °s cm-'.

The conductive material obtained in Production Example 1 was used as a positive electrode material, the material was punched to a predetermined size to serve as a positive electrode, and the lithium was punched to a predetermined size to serve as a negative electrode. and,
These positive and negative electrodes and lithium tetrafluoroborate LiBF4 (electrolyte) were mixed with propylene carbonate (
Using an electrolytic solution dissolved in a solvent), a battery according to the present invention (product A of the present invention) having the structure shown in FIG. 1(A) was made.

In addition, the conductive material obtained in Production Example 23 above was used as the positive electrode material, the positive electrode was made by punching this into a bag of predetermined dimensions, and a separator made of polypropylene nonwoven fabric was used, but in the same manner as product A of the present invention, A battery according to the present invention (product B of the present invention) shown in FIG. 1 (8) was produced.

On the other hand, a polypyrrole film obtained by conventional electrolytic oxidative polymerization is used as a positive electrode material, and this is punched to a predetermined size to make a positive electrode, and this positive electrode is pressed and crimped to the bottom of a positive electrode can through a positive electrode current collector. A comparative battery (comparative quantity C) was produced in the same manner as inventive product A except that a separator made of polypropylene nonwoven fabric was used.

After charging the above three batteries with a current of 0.1 mA for 1 hour, the battery voltage decreased to 2°5V with a current of 0.1 mA.
A series of charging and discharging υ cycles was repeated until the voltage was reached.

FIG. 2 shows the change in battery voltage over time in the 60th cycle of charging and discharging for the product A of the present invention and the comparative product C. still,
In the figure, the solid line shows the voltage change during charging, and the dotted line shows the voltage change during discharging. As is clear from FIG. 2, the product A of the present invention has a lower charging voltage and a higher discharging voltage than the comparative product C, which indicates that its distribution discharge efficiency is improved.

Incidentally, the charging/discharging efficiency in this cycle was 92% for the product A of the present invention, whereas the efficiency for the comparative product C was 80%. The reason why the charge/discharge efficiency of product A of the present invention was improved in this way is that the conductive material used as the positive electrode for the product of the present invention is made of a porous film with good liquid absorption properties as a base material. In addition to improving the liquid-retaining property of the positive electrode itself, in the product A of the present invention, the distance between the electrodes is smaller compared to the comparative amount, and the internal resistance of the valve is reduced. As a result, the increase in charging voltage is suppressed and the discharging voltage is reduced. This seems to be because improvements were made.

Further, FIG. 3 shows the cycle change in charge/discharge efficiency (%) of the product B of the present invention and the comparative product C. As shown in the figure, the charging/discharging efficiency of the comparison amount C begins to decrease after 60 cycles, and decreases to 50% at 100 cycles. On the other hand, product B of the present invention not only exhibits higher charge/discharge efficiency than comparative amount C throughout the entire cycle, but also has a
It can be seen that a high charge/discharge efficiency of 90% is maintained even in the 1st cycle. The reason why the cycle characteristics of comparative amount C are so bad is thought to be that the polypyrrole film of the positive electrode peels off from the positive electrode current collector during the charge/discharge cycle, and the adhesion and contact between the two gradually deteriorate. It will be done. In the case of product B of the present invention, a conductive material made of carbon cloth as a base material is used as the positive electrode, and this base material also serves as a positive electrode current collector, so that polypyrrole, which is the positive electrode material, and current collector are used. The degree of adhesion to the body was extremely good, and the degree to which the polypyrrole peeled off from the current collector during the charge/discharge cycle was extremely small, which is thought to be the reason for the improved cycle characteristics.

Although the above description has been made of a case in which a conductive material is used only for the positive electrode, it is clear that similar effects can be obtained when the conductive material of the present invention is used for the negative electrode or the positive and negative electrodes.

<Effects of the Invention> According to the secondary battery of this invention purchased as described above,
Since we used an electrode made of a conductive material that has excellent oxidation resistance, is easy to manufacture, and is inexpensive, it is easier to manage the electrode production environment, improve the shelf life of the electrode itself, and eliminate inconveniences such as sudden increases in charging voltage. Moreover, the battery cost does not increase. Furthermore, this conductive material can be used as an electrode material that integrates a base material that also serves as a separator or current collector with a single layer of conductive polymer, which not only simplifies the battery assembly process, but also allows the use of a separator as a base material. When used in combination, it is possible to reduce the charging voltage and increase the discharge voltage by reducing the internal resistance of the battery, and when it is used in combination as a current collector, it is possible to improve cycle characteristics. In this case, when a porous material is used as the base material of the conductive material used, there is an advantage that the liquid impregnation of the electrode is improved and the battery characteristics are improved, and its industrial utility value is great.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are cross-sectional views showing battery structures of examples of the present invention, respectively, and Figure 2 is a graph showing changes in battery voltage over time during charge/discharge cycles of the invention product and a comparative amount. , FIG. 3 is a graph showing the cycle characteristics of the product of the present invention and a comparative amount. 1...Positive electrode, 2...Negative electrode, 3...Separator, 4
... Insulating backing, 5... Positive electrode can, 6... Negative electrode can, 7... Negative electrode current collector, 8... Carbon cloth, 9
...Porous polyethylene film.

Claims (1)

[Claims] 1. A base material having a space capable of retaining an oxidizing agent and having at least one surface that is hydrophobic is treated with an oxidizing agent to retain the oxidizing agent only on one surface of the base material. A conductive material obtained by polymerizing a compound having a conjugated double bond on the substrate in a gas phase atmosphere and forming a polymer of the compound on either surface is applied to at least one of the positive electrode or the negative electrode. A secondary battery characterized by being used as one electrode. 2. Dip a base material with one side hydrophobic and the other side hydrophilic in an oxidizing agent aqueous solution, or apply the oxidizing agent aqueous solution to the other side to retain the oxidizing agent on the other side. 2. A secondary battery according to claim 1, characterized in that a conductive material is used. 3. Claim 1, characterized in that a conductive material is used, which is made by applying an aqueous oxidizing agent solution to one side of a base material whose both sides are hydrophobic, and retaining the oxidizing agent on the one side. Secondary batteries listed in section. 4. The secondary battery according to claim 1, which uses a conductive material obtained by treating one side of a hydrophilic base material with a water repellent. 5. The secondary battery according to claim 1, 2, 3, or 4, wherein the compound having a conjugated double bond is a pyrrole-based or thiophene-based compound.