JPH0574459A - Reversible electrode material - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] To provide an electrode material capable of producing a battery having a high energy density and forming an electrode having excellent reversibility capable of extracting a large current at room temperature. Provided is a highly safe lithium battery using the above electrode material. A combination of a compound having a disulfide group and a conductive polymer, or an electrode material having a conductive polymer having a disulfide group, wherein the S—S bond of the disulfide group is cleaved by electrolytic reduction, A sulfur-metal ion bond or a sulfur-proton bond is formed, and the sulfur-metal ion bond or the sulfur-proton bond forms an S-S bond by electrolytic oxidation.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a reversible electrode material, a method for producing a reversible electrode using the reversible electrode material, and a lithium battery using the reversible electrode.

[0002]

2. Description of the Related Art Since the discovery of conductive polyacetylene by Shirakawa et al. In 1971, the use of this conductive polymer as an electrode material has been actively studied. This is because when a conductive polymer is used as an electrode material, it can be expected to manufacture a lightweight and high energy density battery, a large-area electrochromic device, and an electrochemical device such as a biochemical sensor using a microelectrode. .. Since polyacetylene is unstable and poor in practicality as an electrode, other π-electron conjugated conductive polymers have been investigated, and polyaniline, polypyrro-
Relatively stable polymers such as lithium, polyacene, and polythiophene have been developed, and lithium secondary batteries using these as positive electrodes have been developed. Since these polymer electrodes take in not only cations but also anions in the electrolyte during the electrode reaction, the electrolyte in the battery not only acts as a transfer medium of ions but also participates in the battery reaction.
Therefore, there is a problem that an amount of electrolyte commensurate with the battery capacity is required in the battery, and as a result, the energy density of the battery is reduced. The energy density of such a battery is about 20 to 50 Wh / kg, which is about one half of that of an ordinary secondary battery such as a nickel-cadmium storage battery or a lead storage battery.

As an electrode material which can be expected to have a high energy density, US Pat. No. 4,833,048 discloses a disulfide compound. This compound is most simply denoted as R-S-S-R (R is an aliphatic or aromatic organic group and S is sulfur). S-S bond is cleaved by electrolytic reduction, R-S ^{chromatography} out with the cation (M ⁺⁾ in the electrolysis bath
-Forms a salt represented by M ⁺ . This salt returns to the original R-S-S-R by electrolytic oxidation. The above cation (M ⁺ )
A metal-sulfur secondary battery in which a metal M that supplies and captures hydrogen and a disulfide-based compound is combined has been proposed in the aforementioned US patent. In this secondary battery, 150Wh /
An energy density of more than kg, which is comparable to or higher than that of an ordinary secondary battery, can be expected. U.S. Patent No. 4833
048 specification or J. Electrochem Soc., Vol. 136, p.
2570-2575 (1989) describes introducing a catalyst into a disulfide compound electrode. Although an organometallic compound is disclosed as an electrode catalyst, its effect is not specifically shown.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention Although a disulfide compound has been proposed as an electrode material capable of achieving a high energy density as described above, the disulfide compound is disclosed by the inventors of US Pat. No. 4,833,048. J. Electroche
As reported in m.Soc, Vol.136, No.9, p.2570-2575 (1989), the oxidation and reduction potentials are very different.
For example, in the electrolysis of [(C ₂ H ₅ ) ₂ NCSS-] ₂ , the oxidation potential and the reduction potential are separated by more than 1 volt. Therefore, the electron transfer process is extremely slow according to the electrode reaction theory. Therefore, it is difficult to extract a large current suitable for practical use, for example, a current of 1 mA / cm ² or more near room temperature, and a battery having an electrode using such a compound can be used at a high temperature of 100 to 200 ° C. There was a problem of being limited.

The reversible electrode material of the present invention, the method for producing a reversible electrode using the electrode material, and the lithium battery using the reversible electrode solve the above-mentioned conventional problems.

[0006]

The electrode material of the present invention is a combination of a compound having a disulfide group and a conductive polymer, or an electrode material having a conductive polymer having a disulfide group. The S-S bond is cleaved by electrolytic reduction to form a sulfur-metal ion bond or a sulfur-proton bond, and the sulfur-metal ion bond or the sulfur-proton bond forms an S-S bond by electrolytic oxidation.

In a preferred embodiment, the electrode material is
It has a combination of a compound having a disulfide group and a conductive polymer, and the compound having a disulfide group has a cleavable disulfide bond in the molecule.

In a preferred embodiment, the conductive polymer having a disulfide group is obtained by introducing a disulfide group into a π-electron conjugated conductive polymer.

In a preferred embodiment, the conductive polymer having a disulfide group is capable of forming a π-electron conjugated conductive polymer and is obtained by electrolytically polymerizing a monomer having a disulfide group.

The method for producing a reversible electrode of the present invention comprises a step of dimerizing a compound having a thiol group to obtain a dimer having a disulfide group, a monomer capable of forming a π-electron conjugated conductive polymer. , A step of electrolytically polymerizing on an electrode substrate in the presence of the dimer.

The lithium secondary battery of the present invention has a positive electrode, a solid electrolyte, and a negative electrode, and the positive electrode has a sulfur-lithium ionic bond capable of forming an S--S bond of a disulfide group by electrolytic oxidation. And a composition containing a π-electron conjugated conductive polymer as a main component, or a π-electron conjugated conductive polymer having a sulfur-lithium ionic bond capable of forming an S—S bond of a disulfide group by electrolytic oxidation. Is a main component, the solid electrolyte is composed of a salt containing lithium, or a polymer containing the salt as a main component, and the negative electrode,
It is composed of a composition containing aluminum or an aluminum-containing alloy and carbon as main components.

In a preferred embodiment, the solid electrolyte is mixed with the composition forming the positive electrode or the composition forming the negative electrode.

In a preferred embodiment, the solid electrolyte is a polyether obtained by adding at least one selected from the group consisting of ethylene oxide and propylene oxide to a polyamine; a compound having ion-exchangeable layered crystals; and LiX. A lithium salt represented by (where X is an anion of a strong acid).

[0014]

As described above, by using the electrode material of the present invention, it is not necessary to handle chemically active metallic lithium or its alloy at the time of assembling the battery, so that the lithium secondary battery can be safely assembled. .. Further, in the lithium secondary battery assembled in this way, by storing the battery in a discharged state, since metallic lithium is substantially absent in the battery, there is no ignition when the battery is destroyed. Further, by using the battery of the present invention, a larger current can be taken out as compared with a conventional battery using metallic lithium or its alloy as a negative electrode.

[0015]

EXAMPLES The electrode material of the present invention contains (1) a combination of a compound having a disulfide group and a conductive polymer, or (2) a conductive polymer having a disulfide group.

The disulfide group-containing compound used in the first electrode material of the present invention is represented by the general formula (R (S) _y ) _n disclosed in the above-mentioned US Pat. No. 4,833,048.
There is a compound represented by. When this compound is reduced, it can be a reductant represented by R (S) _y H or R (S) _y M. Here, R is an aliphatic group or an aromatic group, S is sulfur, H is a proton, M is a metal atom, y is an integer of 1 or more,
And n is an integer of 2 or more. For example, the reduced form of the above compound is 2,5-dimercaptop-1, which is represented by C ₂ N ₂ S (SH) ₂ .
There are 3,4-thiadiazole and s-triazine-2,4,6-trithiol represented by C ₃ H ₃ N ₃ S ₃ .

A compound having a disulfide group in the molecule and having a configuration that allows cleavage of the S—S bond of the disulfide group to occur reversibly in the molecule is also preferably used. As such a compound, 1 , 8-disulfide naphthalene and the like. The compound having a disulfide group and the compound having a group capable of forming a disulfide group (mercapto group etc.) are collectively referred to as a disulfide compound.

As the electroconductive polymer, a π-electron covalent electroconductive polymer is used, and examples thereof include polymers obtained by polymerizing thiophene, pyrrole, aniline, furan, benzene and the like. Specifically, polyaniline,
There are polypyrrole, polythiophene, polyacene and the like.
These π-electron sharing conductive polymers cause a highly reversible redox reaction at 0 to ± 1.0 volt with respect to Ag / AgCl electrodes. These polymers can have a porous fibril structure depending on the polymerization conditions, can retain a disulfide compound in the pores, and can effectively produce a reversible electrode. The above conductive polymer doped with anions such as iodine exhibits excellent properties as a conductive polymer.

In the first electrode material of the present invention, the above disulfide compound and conductive polymer are used in combination. These combinations can be carried out by a known method such as mixing, impregnation, eutectoid, and overcoating. For example,
A composite electrode can be obtained by forming a conductive polymer fibril layer on a stainless steel substrate by electrolytic polymerization and then impregnating the sulfide layer with the salt of the disulfide compound. Alternatively, the disulfide compound particles may be dispersed in a solvent in which the conductive polymer is dissolved, and then the solvent may be removed to form a layer of the conductive polymer on the surface of the disulfide compound particles. Furthermore, the conductive polymer powder obtained by chemical polymerization or electrolytic polymerization and the disulfide compound powder can be mixed.

As an alternative method, a compound having a disulfide group in the molecule such as 1,8-disulfide naphthalene and having a configuration that allows cleavage of the S—S bond of the disulfide group to occur reversibly in the molecule The electrode material of the present invention can be obtained by polymerizing a monomer capable of forming a π-electron covalent conductive polymer in the presence of the monomer. For example, when aniline is electrolytically polymerized on an electrode substrate in the presence of 1,8-disulfidenaphthalene, a polyaniline-1,8-disulfidenaphthalene composite film is formed. Alternatively, as still another method, a dimerized compound having a thiol group can be used instead of the compound having a steric configuration in which the cleavage of the S—S bond can occur reversibly in the molecule. For example, a dimer of thiazoline is obtained, which is
By using instead of 8-disulfide naphthalene, a polyaniline-2-mercapto-2-thiazoline dimer composite film is formed. In any of the above cases, it is preferable to carry out the polymerization under polymerization conditions such that a film having a fibril structure is formed. In these methods, since the compound in which the thiol group is protected is used, the conductive polymer can be prepared without being hindered. In the obtained composite film, since the disulfide compound and the conductive polymer form a complex, for example, when this is used as a positive electrode of a reversible battery, the disulfide compound may leak into the electrolyte. Absent.

In the second electrode material of the present invention, a conductive polymer having a disulfide bond is used. The conductive polymer having such a disulfide bond may be formed by, for example, (1) introducing a disulfide group into a π-electron sharing conductive polymer; or (2) forming a π-electron sharing conductive polymer. And electrolytically polymerizing a monomer having a disulfide group. As the π-electron sharing system conductive polymer in the first method, the conductive polymer used in the first electrode material or a derivative thereof can be used. For example, a halogenated pyrrole is electrolytically polymerized to form a polyhalogenated pyrrole thin film on an electrode substrate. At this time, as in the case of the first electrode material, it is preferable to carry out the polymerization under the conditions for forming a thin film having a fibril structure. Next, the halogen group is converted into a mercapto group with thiourea or the like. Next, a compound having a mercapto group is reacted therewith to form a disulfide group. As the compound having a mercapto group, a disulfide compound (reduced type having an SH group) used in the first electrode material, for example, 2,5-dimercapto-1,3,4-thiadiazole is suitable. Used. The thin film conductive polymer having a disulfide bond formed in this manner can be used as a reversible electrode. As the monomer capable of forming the π-electron sharing conductive polymer in the second method, a disulfide group is contained in the monomer (thiophene, pyrrole, etc.) capable of forming the conductive polymer used in the first electrode material. The introduced monomer can be utilized. By polymerizing this monomer, a conductive polymer having a disulfide bond can be obtained. For example, a thiophene having a mercapto group is reacted with a dimercapto compound (which is a reduced type and has an SH group) used for the first electrode material, such as 2,5-dimercapto-1,3,4-thiadiazole. By doing so, a thiophene derivative having a disulfide group can be obtained. By electropolymerizing this on an electrode substrate, a film of a conductive polymer having a disulfide group is formed. It is preferable to carry out the polymerization under conditions such that a film having a fibril structure is formed. The conductive polymer film thus formed acts as a reversible electrode.

When electrolytic reduction is carried out when a metal ion or a proton coexists in an electrode using the electrode material of the present invention, the S—S bond of the disulfide group contained in the electrode material is cleaved, resulting in a sulfur-metal ion bond or sulfur. -Proton bonds are formed. When this is electrolytically oxidized again, the original SS
Return to join. Examples of the metal ions include alkali metal ions and alkaline earth metal ions. When an electrode made of the electrode material of the present invention is used as a positive electrode and lithium ions are used as alkali metal ions, an electrode composed of lithium metal or lithium alloy such as lithium-aluminum is used as an electrode for supplying and capturing lithium ions as a negative electrode. And a lithium ion conducting electrolyte is used, a battery having a voltage of 3 to 4 volt can be obtained. When a proton and an electrode composed of a metal hydride such as LaNi ₅ as an electrode for supplying and trapping the proton are used as a negative electrode and an electrolyte conducting protons is used, a battery having a voltage of 1 to 2 volt is obtained. Can be done.

In the combination of the disulfide compound of the electrode material of the present invention and the π-electron covalent conductive polymer, the π-electron covalent conductive polymer is the electrolytic oxidation / oxidation of the disulfide compound.
It acts as an electrode catalyst during the reduction. Also in the case of a π-electron sharing system conductive polymer having a disulfide group, the π-electron sharing system structure acts as an electrode catalyst in the electrolytic oxidation / reduction of the disulfide group. In the case of the conventional disulfide compound alone, the potential difference between the oxidation reaction and the reduction reaction is 1 volt or more. However, in the case of combining the π-electron sharing conductive polymer and the disulfide compound, or in the case of the conductive polymer having a disulfide group, , The potential difference between the oxidation reaction and the reduction reaction is 0.1 volt or less. A disulfide compound combined with a π-electron conjugated conductive polymer or incorporated in such a polymer promotes an electrode reaction, and thus a large current can be taken out even at room temperature. When electrolytic oxidation of the electrical material of the present invention is performed, first, the π-electron conjugated conductive polymer (in the conductive polymer having a disulfide group, the conjugated polymer portion) is oxidized to form an oxidized product of the polymer. Is a reduced disulfide compound (in the case of a conductive polymer having a disulfide group, S
(H or S-metal ion bond part) returns to the original reduced form and an oxidized form of the disulfide compound is generated (disulfide group is formed). When electrolytic reduction is performed,
The conductive polymer first undergoes reduction, and the resulting reductant reduces the disulfide compound (oxidant) and returns to the oxidant, and the disulfide compound becomes the reductant. Introducing an electrocatalyst into a disulfide compound electrode is described in US Pat.
33048 Specification or J. Electrochem Soc., Vol. 136,
p.2570-2575 (1989). However, only an organometallic compound is disclosed as the electrode catalyst, and the effect of the electrode catalyst is not specifically shown. As described above, the π-electron conjugated conductive polymer or the conjugated polymer portion has a function of promoting the transfer of electrons in the redox reaction, and thus acts as a catalyst in the redox reaction and increases the activation energy of the reaction. It has a function to reduce. At the same time, it has the effect of increasing the effective reaction area between the electrode and the electrolyte.

In the lithium battery of the present invention, the electrode made of the electrode material of the present invention is used as a positive electrode, and the electrode made of a composition containing aluminum or an aluminum-containing alloy as a main component is used as a negative electrode, and , A solid electrolyte composed of a salt containing lithium or a polymer containing the salt.

As the material of the positive electrode, a combination of a lithium salt of a reduced form of a compound having a disulfide group and a conductive polymer; or, the S—S bond of the disulfide group is cleaved to become a thiol group, which becomes the lithium salt. A conductive polymer having a group having For example, the lithium salt of the reduced form of the compound having a disulfide group, represented by _{C 2 N 2 S (SLi)} 2 2,5-
Dimercapto-1,3,4-lithium thiolate, (C
Diethyldithiocarbamate represented by ₂ H ₄ ) ₂ C (S) (SLi) and the like can be mentioned. The conductive polymer is
It has a group derived from these compounds. In such an electrode material, lithium ions are liberated by electrolytic oxidation to generate an S—S bond, and conversely, reduction causes an original S ion to return.
-Return to Li.

The carbon material contained in the negative electrode is
There are natural graphite, artificial graphite, amorphous carbon, fibrous carbon, powdery carbon, petroleum pitch carbon and coal coke carbon.
These carbon materials have a diameter or fiber diameter of 0.01 to 1
Particles or fibers having a size of 0 micron and a fiber length of several μm to several mm are preferable.

Examples of aluminum or its alloy contained in the negative electrode include Al, Al-Fe, Al-Si, Al-Zn, Al-Li, Al-Zn-S.
There are i etc. These metallic aluminum or its alloy are preferably flakes obtained by ultra-quenching, spherical or amorphous powder obtained by mechanical pulverization in air or in an inert gas such as nitrogen. The particle size is preferably 1 μm to 100 μm in diameter. The mixing ratio of the carbon material and aluminum or aluminum alloy is 0.01 to 5 parts by weight, preferably 0.
It is from 05 to 0.5 parts by weight. If the amount of the carbon material is 0.01 parts by weight or less, uniform dispersion with aluminum or aluminum alloy powder (including flakes) becomes difficult. For this reason, the carbon material (powder or the like) is agglomerated to cause poor conduction between the aluminum or aluminum alloy particles, and the electrode does not work effectively. On the other hand, when the amount exceeds 5 parts by weight, the aluminum or aluminum alloy powder particles are thickly covered with the carbon material. Therefore, the contact with the electrolyte is broken, and the potential becomes unstable and the polarization becomes large.

The electrolyte of the lithium secondary battery of the present invention is a lithium conductive solid electrolyte (solid or solid at -20 to 60 ° C.), and the solid electrolyte is a salt containing lithium, or It is composed of a polymer containing salt. As the salt containing lithium, LiI, Li ₃ N-LiI-B ₂ O ₃ , L
iI · H ₂ O, Li-β-Al ₂ O _3, etc. As a polymer electrolyte containing these, there is polyethylene oxide in which the lithium salt is dissolved, and a solid electrolyte membrane made of a polyacrylonitrile membrane containing propylene carbonate in which LiClO ₄ is dissolved can be used. As described below, when mixing an electrolyte with at least one of the positive electrode and the negative electrode, a polyether obtained by adding ethylene oxide and butylene oxide to polyamine,
A solid electrolyte composition composed of an ion-exchangeable compound having a layered crystal and a lithium salt is preferably used. The above-mentioned polyether is obtained by adding 10% to a polyamine under an alkaline catalyst.
It can be obtained by addition reaction of ethylene oxide and butylene oxide at 0 to 180 ° C. and 1 to 10 atm. As the polyamine which is a constituent component of the above polyether, polyethyleneimine, polyalkylenepolyamine or derivatives thereof can be used. Examples of the polyalkylene polyamine include diethylene triamine, triethylene tetramine, hexamethylene tetramine, dipropylene triamine and the like. The number of moles of ethylene oxide and butylene oxide added is 2 to 150 moles per active hydrogen atom of the polyamine. The molar ratio of ethylene oxide (EO) and butylene oxide (BO) added is 80/20 to 10/90.
(= EO / BO). The polyether thus obtained has an average molecular weight of 10 to 5,000,000. This polyether is preferably contained in the solid electrode composition in a proportion of 0.5 to 20% by weight. As the compound having an ion-exchangeable layered crystal structure, montmorillonite, hectorite, saponite, clay minerals containing silicates such as smectite, zirconium phosphate, phosphoric acid esters such as titanium phosphate, vanadic acid, antimonic acid, Tungstic acid; or those obtained by modifying them with an organic cation such as a quaternary ammonium salt or an organic polar compound such as ethylene oxide and butylene oxide. In this solid electrolyte composition, polyether, which is one of the constituent components, has a surface-active effect. Therefore, when the composition is mixed with at least one of the positive electrode and the negative electrode, the composition is uniformly dispersed by the action of the polyether, and the polarization becomes small.

The lithium secondary battery of the present invention can usually be prepared by the following method. For example, first, the components of the positive electrode, the negative electrode, and the electrolyte are mixed and formed into a film. A positive electrode film, an electrolyte film, and a negative electrode film are laminated in this order and pressure-bonded to obtain a unit cell. A lithium secondary battery of the present invention can be obtained by attaching a copper foil or a lead wire to the positive electrode and the negative electrode of the unit cell of this laminate, if necessary, and putting them in a case. It is recommended to mix the above electrolyte components with at least one of the positive electrode and negative electrode components to prepare a battery.

When the lithium secondary battery of the present invention is charged, Li is liberated from the S-Li bond of the positive electrode and the S-S bond is formed. Lithium metal is uniformly deposited on the surface of the negative electrode or inside the negative electrode (when the components of the negative electrode and the components of the electrolyte are mixed). Since lithium is directly deposited from the electrolyte, it is not mixed with impurities such as oxygen. Therefore,
Current concentration is less likely to occur even after repeated charging and discharging,
The internal short circuit of the battery is effectively prevented. Since the metallic lithium generated by charging (electrolysis) and the electrolyte are electrically connected very well, it is possible to reduce the polarization during discharging, and it is possible to extract a large current. Particularly effective results are obtained when the electrolyte is mixed with the positive electrode and / or the negative electrode as described above. In this case, it is particularly advantageous to use lithium salts, polyethers and compounds having layered crystals as the electrolyte.

By the way, conventional lithium secondary batteries (3 to
With a high voltage of 4 V and a high energy density of 100 Wh / Kg or more), metal lithium or lithium alloy is used for the negative electrode, and titanium disulfide, molybdenum disulfide capable of reversibly taking lithium ions in and out of the positive electrode, Batteries using inorganic materials such as vanadium oxide and cobalt oxide have been proposed. As the electrolyte, a liquid electrolyte prepared by dissolving a lithium salt such as lithium perchlorate or lithium borofluoride in an aprotic organic solvent such as propylene carbonate or dimethoxyethane is exclusively used. The ionic conductivity of this liquid electrolyte is two to three orders of magnitude lower than the aqueous electrolytes used in nickel-cadmium secondary batteries or lead-acid batteries, so in order to obtain a large current comparable to those batteries, It is necessary to have a large area and a thin separator. Therefore, the positive electrode is usually
It is prepared by processing a composition obtained by mixing a powdery positive electrode active component (such as the above titanium disulfide), a conductive material and a binder into a sheet. In addition to processing into a sheet shape, the electrode area of the positive electrode can be increased by reducing the particle size of the powder or using porous powder. However, in order to obtain a negative electrode with a large area, it is necessary to process it into a thin foil shape using metallic lithium or a lithium alloy that is soft and difficult to powder process. The lithium battery is obtained by stacking the positive electrode and the negative electrode, which have been processed into the thin sheet shape, with a separator such as a polypropylene non-woven fabric interposed therebetween, spirally winding them into a battery container and pouring an electrolytic solution. Since metallic lithium is used, it is necessary to perform all operations in a dry inert gas.

An important factor in assembling a lithium secondary battery is to make the electrodes that come into contact with the electrolyte uniform and homogeneous over the entire surface. The positive electrode is usually composed of a composition containing a positive electrode active component, a conductive material and a binder,
A relatively homogeneous material can be obtained by selecting a chemically stable positive electrode active material and mixing it uniformly. However, it is difficult for the negative electrode to uniformly and homogeneously process metallic lithium or lithium alloy foil having a thickness of several μm to several tens of μm through a multi-step rolling process, and it is difficult to locally pull it in the battery assembling process. It is difficult to receive and assemble uniformly. Therefore, during battery charging / discharging, the dissolution / deposition reaction of lithium progresses unevenly within the negative electrode surface, and the unevenness increases as the charging / discharging cycle is repeated.
Eventually, the current locally concentrates and dendritic lithium deposition occurs, breaking through the separator and connecting to the positive electrode, causing an internal short circuit. When an internal short circuit occurs, a large current flows, the battery heats up, the vapor pressure of the organic solvent rises and the battery bursts, metal lithium is exposed to the atmosphere and reacts with water, hydrogen is generated, and ignition occurs. It is extremely dangerous.

On the other hand, since the lithium secondary battery of the present invention can be prepared without using metallic lithium or a lithium alloy, it does not require complicated operations and is safe. When the battery is stored in the discharged state, the metallic lithium does not substantially exist in the battery in the discharged state, so that even if the battery is destroyed, it does not ignite. When the battery is charged, metallic lithium is uniformly deposited as described above, and therefore internal short circuits are extremely unlikely to occur even when repeatedly charged and discharged, which is safe. When powdery, fibrous or porous aluminum or its alloy is used as the material of the negative electrode, the electrode area becomes large, so that it is not necessary to process it into a thin sheet or film like in the past.

Example 1 1M (M = mol / dm ³ ) aniline and 5M Na ₂ SO ₄ were dissolved in a sulfuric acid aqueous solution to obtain a sulfuric acid acidic aqueous solution having a pH = 1.0. In this aqueous solution, electrolysis was performed at a constant potential of 1.2 to 1.5 volt with respect to the saturated calomel reference electrode to form a polyaniline film having a fibril structure and a thickness of about 20 μm on the graphite electrode. The graphite electrode having the polyaniline thin film thus obtained was vacuum-dried at 80 ° C. for a whole day and night, and then 2,5-dimercaptop-1,3,4-thiadiazole was added at 5 mM, L
Ag / Ag in dimethylformamide containing 1M iClO ₄
A composite electrode was prepared by electrolysis at a constant potential of +0.8 volt with respect to the potential of the Cl reference electrode.

In dimethylformamide in which 1M LiClO ₄ was dissolved, -0.7 to +0.2 volt with respect to the potential of the Ag / AgCl reference electrode.
This electrode was electrolyzed at room temperature by linearly increasing or decreasing the potential at a rate of 50 mV / sec between. As a result, the current-voltage characteristic shown by the curve A in FIG. 1 was obtained. Next, as a comparative example, similar electrolysis was performed using a graphite electrode having no polyaniline thin film. As a result, the current-voltage characteristic shown by the curve B in FIG. 1 was obtained. Further, similar electrolysis was performed using a graphite electrode having only a polyaniline thin film. As a result, the current-voltage characteristic shown by the curve C in FIG. 1 was obtained.

In the curve A, the current peak value corresponding to redox is calculated from the current peak value of the graphite electrode having only polyaniline and the current peak value of 2,5-dimercaptop-1,3,4-thiadiazole. Is also big. By this,
It can be seen that a large current can be taken out by using the electrode of the present invention using polyaniline and a disulfide compound. Further, in the curve A, the current peak position corresponding to redox exists between the current peak position of the graphite electrode having only polyaniline and the current peak position of 2,5-dimercaptop-1,3,4-thiadiazole. .. Among the current peaks corresponding to the redox of 2,5-dimercaptop-1,3,4-thiadiazole, the current peak position corresponding to the reduction reaction was obtained at around -0.2 volt. In the graphite electrode without (curve C), the current peak position was obtained near -0.6 volt). That is, π
It can be seen that the presence of polyaniline, which is an electron-conjugated conductive polymer, promotes the redox of 2,5-dimercaptop-1,3,4-thiadiazole. In the current-voltage characteristic curve B obtained with the graphite electrode having no polyaniline thin film as described above, the oxidation peak and the reduction peak corresponding to the redox of 2,5-dimercaptop-1,3,4-thiadiazole. -Potential difference
It is close to 0.6volt. As described above, in the graphite electrode having no polyaniline thin film, the redox is quasi-reversible and the reaction rate is slow. For example, when this electrode is used as a positive electrode of a battery, the voltage difference between charging and discharging is as large as 0.6 volt or more, so that a battery whose efficiency significantly decreases when charged and discharged with a large current can be obtained.

Example 2 Aniline was chemically polymerized in an acidic aqueous solution by using cupric borofluoride as an oxidizing agent. As a result, a porous polyaniline powder having an average particle size of 0.3 μm and a fibril structure was obtained.
1 part by weight of this polyaniline powder and 2,5-dimercaptop-1,3,4
-1 part by weight of thiadiazole powder and 0.1 part by weight of carbon black are mixed with low density polyethylene (trade name: Excellen V
L-200, density = 0.9, manufactured by Sumitomo Chemical Co., Ltd.) was mixed in toluene. Next, this mixture was applied onto a 200-mesh stainless steel net and dried to form a sheet-shaped composite electrode having a thickness of about 100 μm.

Using this composite electrode as a positive electrode, a solid electrolyte membrane was prepared by dissolving 1M LiClO ₄ in a propylene carbonate.
A solid battery A having a size of 28 × 28 mm was constructed by using a polyacrylonitrile film having a thickness of about 70 μm and containing metallic lithium as a negative electrode.

This battery was charged at room temperature with a constant voltage of 3.6 V for 17 hours, and then charged at 1 μA, 10 μA and 100 μA.
A, 500 μA and 1 mA of current were discharged for 3 seconds each. The current-voltage characteristics were evaluated by recording the voltage of each battery. The result is shown in the curve (a) of FIG. As a comparative example, a sheet-like electrode having a thickness of about 100 μm and containing no polyaniline powder was prepared by using the same method. Battery B was constructed by using this electrode. The current-voltage characteristic of this battery is shown by the curve (b) in FIG. Battery A has a smaller polarization than battery B, and a large current can be obtained by using battery A.

In these examples, by using an electrode in which a disulfide compound and a π-electron conjugated conductive polymer were compounded, it was difficult to use a conventional disulfide compound at a large current. Electrolysis is possible.
By using this composite electrode for the positive electrode and metallic lithium for the negative electrode, charging and discharging can be expected with a large current,
A secondary battery having a high energy density can be constructed.

In this example, only the battery using the composite electrode was shown. However, by using the composite electrode of the present invention as a counter electrode, an electrochromic device having a fast coloring / fading speed, a biochemical sensor such as a glucose sensor having a fast response speed, and an electrochemical analog memory having a fast writing / reading speed are configured. You can also do it.

Example 3 2-Pyrrolecarboxylic acid 11
Dissolve g (0.1 mol) in 200 ml of acetonitol and dissolve at 0 ℃
After cooling to 16 g (0.1 mol) of bromine was added dropwise to this solution. The solution was stirred for 60 minutes and then neutralized by adding a 20% aqueous sodium carbonate solution. Ether was added to this solution, and the aqueous layer was extracted with ether. After the extracted ether solution was dried, ether was removed. As a result, 3,
A mixture of 2-pyrrolecarboxylic acid disubstituted with bromine at positions 4 and 5 and 2-pyrrolecarboxylic acid monosubstituted with bromine was obtained. 6 g of this mixture was added to 20 xylene.
Dissolve in a mixed solution of 0 ml and ethanolamine 10 ml. 2
Heated to reflux for hours. Then wash with 30% aqueous acetic acid,
The organic layer was separated and dried. Xylene was removed from this solution to obtain 3 g of a mixture of 2-substituted bromopyrrole and 1-substituted bromopyrrole. Redissolve this mixture in xylene,
Fractionation was performed by using a silica gel column to obtain 1 g of 3-bromopyrrole.

The 3-bromopyrrole thus obtained was dissolved in an aqueous sulfuric acid solution to give 1 mol / mol of 3-bromopyrrole.
1 and 5 mol / l pH 1.0 sulfuric acid aqueous acid solutions were obtained, respectively. In this aqueous solution, by electrolyzing at a constant potential of 1.2 to 1.5 V with respect to the potential of the saturated calomel reference electrode, a poly 3-containing fibril structure having a thickness of about 20 μm is formed.
A bromopyrrole film was formed on the graphite electrode. The graphite electrode having the poly-3-bromopyrrole thin film thus obtained was vacuum dried at 80 ° C. for 24 hours. This polybromopyrrole 1g (0.01mol) was reacted with thiourea 0.8g (0.01mol) to introduce a mercapto group, and in the presence of chlorine, 2,
1.2 g (0.01 mol) of 5-dimercapto-1,3,4-thiadiazole was reacted to obtain an electrode made of polypyrrole into which disulfide shown in the following formula was introduced.

[0044]

[Chemical 1]

By changing the potential linearly at a rate of 50 mV / sec between -0.7 and +0.2 V with respect to the potential of the Ag / AgCl reference electrode in dimethylformamide in which 1 mol / l LiClO ₄ was dissolved, The electrodes were electrolyzed at room temperature. As a result, the current-voltage characteristic shown by the curve A in FIG. 3 was obtained.

As a comparative example, a graphite electrode was used in dimethylformamide in which 0.05 mol / l of 2,5-dimercapto 1,3,4-thiadiazole and 0.5 mol / l of LiClO ₄ were dissolved, and the potential of the Ag / AgCl reference electrode was used. In contrast, electrolysis was performed at a constant potential of + 0.8V. By similarly electrolyzing the electrode having no polypyrrole, the current-voltage characteristic shown by the curve B in FIG. 3 was obtained. further,
A graphite electrode having only a polypyrrole thin film was prepared, and similar electrolysis was performed using the graphite electrode to obtain a current-voltage characteristic shown by a curve C in FIG. In the curve A, the current peak value corresponding to redox is larger than the current peak value of the graphite electrode having only polypyrrole and the current peak value of 2,5-dimercaptop-1,3,4-thiadiazole. This shows that a large current can be extracted by using the electrode of the present invention using polypyrrole and a disulfide compound. Further, in the curve A, the current peak value corresponding to redox is present between the current peak position of the graphite electrode having only polypyrrole and the current peak position of 2,5-dimercaptop-1,3,4-thiadiazole. To do. Among the current peaks corresponding to the redox of 2,5-dimercapto-1,3,4-thiadiazole, the current peak position particularly corresponding to the reduction reaction is near -0.2 V (when using a graphite electrode having only polypyrrole) -0.6V
Is). That is, by using polypyrrole, which is a π-electron conjugated conductive polymer in which 2,5-dicarcapto-1,3,4-4 thiadiazole is incorporated, the 2,5-dimercapto-1,
It can be seen that the redox of 3,4-thiadiazole is promoted.

In the current-voltage characteristic curve B obtained with the graphite electrode having no polypyrrole thin film, 2,5-dimercaptop-
The potential difference between the oxidation peak and the reduction peak, which corresponds to the redox of 1,3,4-thiadiazole, is near 0.6V. In such an electrode, redox is quasi-reversible and the reaction rate is slow. For example, when this electrode is used as the positive electrode of a battery, the voltage difference between charging and discharging is as large as 0.6 V or more, so that charging / discharging with a large current gives a battery with poor charging / discharging efficiency.

In this embodiment, the case where pyrrole is used as the monomer capable of forming the conductive polymer has been described. However, the present invention is not limited to this,
Needless to say, the same effect can be obtained by using other monomers such as aniline.

As is clear from the above description of the embodiment, in this embodiment, the electrode is obtained by introducing the disulfide compound into the conductive polymer. By using this electrode, it becomes possible to carry out electrolysis at a large current, which is difficult when using an electrode composed only of a conventional disulfide compound. Then, by using this electrode for the positive electrode and metallic lithium for the negative electrode, a secondary battery having a high energy density capable of charging and discharging with a large current can be formed.

By using the electrode of the present invention as the counter electrode,
In addition to batteries, electrochromic devices with fast coloring / fading speed, biochemical sensors such as glucose sensor with fast response speed, and electrochemical analog memory with fast writing / reading speed can be obtained.

Example 4 (1) Synthesis of 1,8-disulfide naphthalene 60 g (0.27) of 1-aminonaphthalene-8-sulfonic acid
(mol) was kneaded with water in a mortar to form a paste. The paste was transferred to a flask and 200 ml of water and 20 ml of sulfuric acid were added. To this, a solution of 30 g (0.43 mol) of sodium nitrate in 100 ml of water was added with stirring for about 30 minutes. The temperature of the obtained solution is -10-
The polymerization reaction was carried out for about one and a half hours while keeping at 15 ° C. The diazonium salt formed was filtered and the reaction solution was washed with 100 ml of cold water. Then 200 ml of sodium disulfide solution was added to this salt. This solution was left at room temperature for 3 hours. Hydrochloric acid was added dropwise to this to adjust the pH to 7.5, and the precipitated sulfur was removed. Thus, 45 g of 8,8′-dithiodi-1-naphthalene sulfate sodium salt was obtained. This salt was put into cold water, and then 30 g (0.14 mol) of phosphorus pentachloride was slowly added and reacted. The reaction solution was returned to room temperature and left for 30 minutes. The reaction product was washed with benzene until decolorized, and the filtrate obtained by filtration was concentrated to obtain a solid product. This was recrystallized using methanol. Thus, 16 g of naphtho [1,8-c, d] -1,2-dithiol 1,1 dioxide was obtained. 16 g of this compound was reacted in a hydrochloric acid solution containing zinc powder for 1 hour to obtain 10 g of 1,8-disulfide naphthalene. (2) Preparation of composite electrode of 1,8-disulfide naphthalene and polyaniline 0.5M Na ₂ SO ₄ (adjusted to pH 1) and aniline 0.1M solution were added to the solution obtained in (1) 8-Disulfide naphthalene was added so as to have a concentration of 10 mmol / l. This solution was measured against the potential of a saturated calomel reference electrode to 1.
A polyaniline-1,8-disulfide naphthalene composite film having a fibril structure and a thickness of about 20 μm was formed on the graphite electrode by electrolysis at a constant potential of 2V. (3) Cyclic voltammetry LiClO ₄ dissolved in 1 M in dimethylformamide was -0.7 to the potential of Ag / AgCl reference electrode.
The potential was linearly increased and decreased at a rate of 50 mV / sec between +0.2 V and the electrode obtained in (2) was electrolyzed at room temperature. As a result, the current-voltage characteristic shown by the curve A in FIG. 4 was obtained. As a comparative example, 10 mol / l of 1,8-disulfide naphthalene was used.
And in dimethylformamide in which LiClO ₄ was dissolved at 0.5 mol / l, the potential was linearly increased / decreased at a rate of 50 mV / sec between −0.7 and +0.2 V with respect to the potential of the Ag / AgCl reference electrode. The graphite electrode was electrolyzed. As a result, the current-voltage characteristic shown by the curve B in FIG. 4 was obtained. Further, the same electrolysis was performed on the graphite electrode having only the polyaniline polymerized film to obtain the current-voltage characteristics shown by the curve C in FIG.

In the curve A, the current peak value corresponding to redox is larger than the current peak value of the graphite electrode having only the polyaniline polymer film and the current peak value of 1,8-disulfide naphthalene. This shows that a large current can be extracted by using the electrode of the present invention using the polyaniline polymer film and the disulfide compound. Further, in the curve A, the current peak position corresponding to redox exists between the current peak position of the graphite electrode having only the polyaniline polymer film and the current peak position of 1,8-disulfide naphthalene. Among the current peaks corresponding to redox of 1,8-disulfide naphthalene, the current peak position particularly corresponding to the reduction reaction is −
It is around 0.2 V (at the 1,8-disulfide naphthalene electrode without polyaniline (curve B), −0.
6V). It can be seen that the oxidation-reduction of 1,8-disulfide naphthalene is promoted by the presence of the thiophene derivative polymer, which is an ionic-electron mixed conductor polymer.

As described above, in the current characteristics (curve B) obtained with the graphite electrode having no polyaniline,
The potential difference between the oxidation peak and the reduction peak corresponding to the redox of 8-disulfide naphthalene is close to 0.6V. In such an electrode, redox is quasi-reversible and the reaction rate is slow. For example, when this electrode is used as the positive electrode of a battery, the voltage difference between charging and discharging is as large as 0.6 V or more, so that a battery with a large decrease in efficiency can be obtained by charging and discharging with a large current.

In this embodiment, the case of using polyniline has been described, but the same effect can be obtained by using other conductive polymers. Although electrolytic polymerization is used as the polymerization method in this example, a composite film can be prepared by ordinary oxidative polymerization. Further, it goes without saying that the same effect can be obtained by pulverizing the polymer film of the present invention and mixing it with a current collector.

The reversible electrode of this embodiment is used as an application other than a battery, by using an electrode as a counter electrode, an electrochromic element having a fast coloring / fading speed, a biochemical sensor such as a glucose sensor having a fast response speed, writing / reading. Used for high speed electrochemical analog memory.

As is clear from the above description of the embodiment,
According to the present invention, since a reversible electrode is constituted by using a compound having a disulfide bond in the molecule and a conductive polymer, it is difficult for a conventional electrode constituted only by a disulfide compound to generate a large current. Can be electrolyzed. By using this electrode for the positive electrode and metallic lithium for the negative electrode, a secondary battery which can be charged and discharged with a large current and has a high energy density can be formed.

Example 5 84 g (1 mol) of thiophene and 100
ml of carbon tetrachloride was mixed and cooled to 0 ° C. To this, 500
A solution of g (3.1 mol) of bromine in 300 ml of carbon tetrachloride was gradually added. After mixing all of these, carbon tetrachloride was distilled off, 15 g of sodium hydroxide was added, and the mixture was heated on a steam bath for 4 hours. The alkali layer was separated and removed from this mixture, the residue was dried, and then a mixture of mono-substituted, di-substituted and tri-substituted thiophene bromide was obtained by distillation. This mixture was dissolved in xylene and fractionated by using a silica gel column to obtain 30 g of 2,2,3-tribromothiophene.
Obtained.

32 g (0.1 mol) of 2, thus obtained,
2,3-tribromothiophene and 6.5 g (0.2 mol) zinc metal
6 g (0.2 mol) of acetic acid was mixed and reacted to obtain 3-bromothiophene.

8.0 g (0.05 mol) of 3-bromothiophene thus obtained was reacted with 4 g of thiourea in acetonitrile to obtain 2.0 g (0.01 mol) of 3-mercaptothiophene. This 3-mercaptothiophene was dissolved in chlorine to give 2,5-dimercapto-1,3,4-thiadiazole 1.2 g (0.01 mol).
It was reacted with l) to obtain thiophene having a disulfide group introduced therein.

By using the thus obtained thiophene derivative (1 mol / l) as a monomer and lithium perchlorate as a supporting electrolyte in propylene carbonate, 1.2 to 1.5 relative to the potential of a saturated calomel reference electrode was obtained. Electrolysis was performed at a constant potential of V. Thereby, a thiophene derivative polymer film having a fibril structure and a thickness of about 20 μm was formed on the graphite electrode.

In dimethylformamide in which 1M LiClO ₄ was dissolved, the potential of the Ag / AgCl reference electrode was -0.7 to +0.
The potential was linearly increased and decreased at a rate of 50 mV / sec between 2 V, and this electrode was electrolyzed at room temperature. As a result, the current-voltage characteristic referred to by the curve A in FIG. 5 was obtained. As comparative examples, 0.05 mol / l of 2,5-dimercaptose 1,3,4-thiodiazole and 0.5 mol / l of LiClO ₄ were used.
l Potential electrolysis was carried out in dissolved dimethylformamide at +0.8 V against the potential of the Ag / AgCl reference electrode, and a graphite electrode without polythiophene was electrolyzed in the same manner. As a result, the current-voltage characteristic shown by the curve B in FIG. 5 was obtained. Further, similarly, a graphite electrode having only a polythiophene thin film was electrolyzed. As a result, the current-voltage characteristic shown by the curve C in FIG. 5 was obtained.

In the curve A, the current peak value corresponding to redox was calculated from the current peak value of the graphite electrode having only polythiophene and the current peak value of 2,5-dimercaptop-1,3,4-thiadiazole. Is also big. This shows that a large current can be taken out by using the electrode of the present invention using polythiophene and a disulfide compound.
Furthermore, in curve A, the current peak position corresponding to redox exists between the current peak position of the graphite electrode having only polythiophene and the current peak position of 2,5-dimercaptop-1,3,4-thiadiazole. To do. Among the current peaks corresponding to redox of 2,5-dimercapto-1,3,4-thiadiazole, the position of the current peak particularly corresponding to the reduction reaction is around -0.2V (2,5-dimercapto-containing no polythiophene- At the 1,3,4-thiadiazole electrode (curve B) -0.6V). It can be seen that the presence of the conductive polymer polythiophene promotes the redox of 2,5-dimercaptop-1,3,4-thiadiazole.

As described above, in the current-voltage characteristic curve B obtained with the graphite electrode having no polyaniline thin film,
The potential difference between the redox peak and the redox peak corresponding to redox of 2,5-dimercaptop-1,3,4-thiadiazole is close to 0.6V. In such an electrode, redox is quasi-reversible and the reaction rate is slow. For example, when this electrode is used as the positive electrode of a battery, the voltage difference between charging and discharging is as large as 0.6 V or more, so that a battery with poor charging / discharging efficiency is obtained when charging / discharging with a large current.

In this embodiment, the case of using polythiophene has been described, but the present invention is not limited to this, and the same effect can be obtained by using other conductive polymers. Further, it goes without saying that the same effect can be obtained by crushing the polymer film of this example and mixing it with a current collector.

As is clear from the above description of the embodiment,
According to the present invention, a polymer is obtained by polymerizing a monomer obtained by introducing a disulfide compound into a monomer capable of forming a conductive polymer, and an electrode is constituted by using this polymer as a main constituent component. It is possible to perform electrolysis with a large current, which was difficult with an electrode composed only of a disulfide compound. By using this electrode for the positive electrode and metallic lithium for the negative electrode, charging / discharging with a large current is possible,
A secondary battery having a high energy density can be constructed.

The reversible electrode of this embodiment is used as an application other than a battery, by using an electrode as a counter electrode, an electrochromic element having a fast coloring / fading speed, a biochemical sensor such as a glucose sensor having a fast response speed, writing / reading. Used for high speed electrochemical analog memory.

(Example 6) (1) Oxidative polymerization of 2-mercapto-2-thiazoline (preparation of dimer) 60 g (0.5 mol) of 2-mercapto-2-thiazoline was dissolved in 100 ml of dimethyl sulfoxide. Oxygen was blown into this solution, and the solution was left at room temperature for one day to allow oxidative polymerization. The reaction solution is subjected to preparative thin layer chromatography,
The target 2-mercapto-2-thiazoline dimer
8 g (0.2 mol) was obtained. (2) Preparation of composite electrode of 2-mercapto-2-thiazoline dimer and polyaniline 2-mercapto-2-in a solution containing 0.5M Na ₂ SO ₄ (adjusted to pH = 1) and 0.1M aniline The 2-mercapto-2-thiazoline dimer obtained in the item (1) of this Example was added so that the amount of the thiazoline dimer was 10 mmol / l. This solution was measured against the potential of a saturated calomel reference electrode to 1.
By electrolyzing at a constant potential of 2 to 1.5 V, polyaniline-2- having a fibril structure and a thickness of about 20 μm-2-
A mercapto-2-thiazoline dimer composite film was formed on a graphite electrode.

For comparison, 0.5 M Na ₂ SO ₄ (pH =
2) so that 2-mercapto-2-thiazoline becomes 10 mmol / l in a solution containing 1) and 0.1 M aniline.
-Mercapto-2-thiazoline was added and electrolysis was attempted at a constant potential of 1.2 to 1.5 V with respect to the potential of the saturated calomel reference electrode, but an attempt was made to produce an electropolymerized membrane, but a composite membrane was not produced. .. (3) Cyclic voltammetry At room temperature, with respect to the potential of the Ag / AgCl reference electrode in dimethylformamide in which 1M LiClO ₄ was dissolved,
The polyaniline-2-mercapto-2-thiazoline dimer composite electrode obtained in the item (2) of this example was obtained by linearly increasing / decreasing the potential between 0.7 and +0.2 V at a rate of 50 mV / sec. Was electrolyzed. As a result, the current-voltage characteristic curve shown by the curve A in FIG. 1 was obtained. As a comparative example, 2-mercapto-
2-thiazoline 10 mmol / l, LiClO ₄ 0.5 mol
/ l Using a graphite electrode in dissolved dimethylformamide, -0.7 to +0.2 relative to Ag / AgCl reference electrode
Electrolysis was performed by linearly increasing or decreasing the potential between V at a rate of 50 mV / sec. As a result, the current-voltage characteristic curve shown by the curve B in FIG. 6 was obtained. Furthermore, a graphite electrode having only a polyaniline polymer film was electrolyzed by the same method. as a result,
The current-voltage characteristic curve shown by the curve C in FIG. 8 was obtained.

In the curve A, the current peak value corresponding to redox is larger than the current peak value of the graphite electrode having only the polyaniline polymer film and the current peak value of 2-mercapto-2-thiazoline. This shows that a large current can be taken out by using the electrode according to the method of the present invention using the polyaniline polymer film and the disulfide compound. Furthermore, in the curve A, the current peak position corresponding to redox is the same as the current peak position of the graphite electrode having only the polyaniline polymerized film and 2-mercapto-
It exists between the current peak position of 2-thiazoline. Two
-Among the current peaks corresponding to the redox of mercapto-2-thiazoline, the current peak position particularly corresponding to the reduction reaction is around -0.2 V (only the polyaniline polymer film having no 2-mercapto-2-thiazoline It has -0.6 V in the graphite electrode (curve B). It can be seen that the presence of polyaniline promotes the redox of 2-mercapto-2-thiazoline.

In the current-voltage characteristic (curve B) obtained with the graphite electrode having no polymer as described above, the potential difference between the oxidation peak corresponding to the redox of 2-mercapto-2-thiazoline and the reduction peak was found. It is close to 0.6V. In such an electrode, redox is quasi-reversible and the reaction rate is slow.
For example, when this electrode is used as the positive electrode of a battery, the voltage difference between charging and discharging is as large as 0.6 V or more, so that a battery with a large decrease in efficiency can be obtained by charging and discharging with a large current. (4) Charging / discharging cycle characteristics A battery was made with the following constitution. As the working electrode, the polyaniline-2-mercapto-2 obtained in the item (2) of this Example was used.
-Using a thiazoline dimer composite electrode, L as a reference electrode
i-line was used. A Li foil was used as a counter electrode, and a dimethylformamide solution in which 1M LiClO ₄ was dissolved was used as an electrolyte solution. With this battery, the charging potential is 4.0V and the
After charging for an hour, final voltage 2.0V, discharge current 0.5mA
A charge / discharge cycle characteristic test was performed under the conditions of. As a result, the charge / discharge cycle characteristic curve shown by the curve A in FIG. 7 was obtained. In FIG. 7, the horizontal axis represents the number of cycles, and the vertical axis represents the discharge capacity after each charge / discharge cycle test when the discharge capacity in the first cycle is 100. As a comparative example, a similar battery was constructed using a composite electrode prepared by mixing polyaniline, 2-mercapto-2-thiazoline and polyethylene oxide in a weight ratio of 3: 1: 1 as a working electrode. Using this battery, a charge / discharge cycle characteristic test was conducted under the same conditions. As a result, the curve B in FIG.
The charge-discharge cycle characteristic curve referred to in FIG.

In the charge / discharge cycle characteristic curve (curve A) of this example, the charge / discharge cycle characteristic is 50% of the initial capacity at 50 cycles, and the charge / discharge cycle characteristic is excellent. On the other hand, in the charge / discharge cycle characteristic curve (curve B) of the comparative example, the charge / discharge efficiency decreases from about 10 cycles.

Although the case where polyaniline is used as the conductive polymer has been described in this embodiment, the same effect can be obtained by using the other conductive polymers described above. Although the case where electrolytic polymerization is used as the polymerization method has been described, the composite film can be prepared by using ordinary oxidative polymerization. Further, it is obvious that the same effect can be obtained by pulverizing the polymer film of this example and mixing it with the current collector.

In this embodiment, 2-mercapto-2-thiazoline was used as the compound having a thiol group, but the same reaction can be performed by using another compound having a thiol group. Further, the electrode can be formed by using a compound having two or more kinds of thiol groups. For example, a compound having a plurality of thiol groups in a molecule and a compound having one thiol group are prepared by oxidative copolymerization to form a copolymer, and a polymer having an apparently protected thiol group (multimer It is also possible to co-exist during the electrolytic polymerization of the monomer capable of forming a conductive polymer.

As is clear from the above description of the embodiment,
A conventional disulfide compound was used by using an electrode mainly composed of a conductive polymer and a dimer (multimer) obtained by intermolecularly disulfide-bonding a compound having a thiol group according to the method of the present invention. It is possible to electrolyze with a large current, which was difficult with a reversible electrode. This electrode can be produced by electrolytic polymerization or chemical oxidative polymerization. By using this electrode for the positive electrode and metallic lithium for the negative electrode, a high energy density secondary battery capable of charging and discharging with a large current can be constructed.

The electrode according to the method of this embodiment is used as an electrode other than a battery, by using the electrode as a counter electrode, an electrochromic device having a fast coloring / fading speed, a biochemical sensor such as a glucose sensor having a fast response speed, writing / reading. It is possible to obtain an electrochemical analog memory having a high speed.

Example 7 Polyethyleneimine containing 10 N atoms in the molecule was mixed with ethylene oxide (E
O) and butylene oxide (BO) were added so that the ratio of EO and BO was 30/70. The polyether having an average molecular weight of 180,000 thus obtained was dissolved in acetonitrile to prepare a 20 wt% polyether solution. Further, LiCF ₃ SO ₃ as a lithium salt was dissolved in the polyether solution at a ratio of 10% by weight. In this polyether solution, the solid content (polyether, LiCF ₃
A γ-zirconium phosphate powder having an average particle diameter of 15 μm was added so that the total amount of SO ₃ and γ-zirconium phosphate) was 30% by weight. This solution was stirred and mixed at 40 ° C. for 24 hours to obtain an electrolyte slurry. The electrolyte slurry was applied onto a smooth Teflon plate by using a doctor blade. This was dried in a stream of dry argon at 130 ° C. for 1 hour and further vacuum dried for 5 hours to obtain an electrolyte sheet having a size of 80 × 80 mm and a thickness of 85 μm.

Next, an electrolyte slurry 1 having the same composition as the above
0.1 part by weight of artificial graphite powder having a degree of graphitization of 48% and an average particle diameter of 2 μm, 2 parts by weight of 2,5-dimercaptop-1,3,4-lithium thiolate, and polyaniline powder of 0. 5 parts by weight was added and mixed to obtain a positive electrode slurry. The above polyaniline powder is 1
PH = 1.0 with M (M = mol / dm ³ ) aniline and 5M Na ₂ SO ₄
It was obtained by electrolysis at a constant potential of 1.2 to 1.5 volt with respect to the potential of a saturated calomel reference electrode in the sulfuric acid acidic aqueous solution. This positive electrode slurry was applied onto a smooth Teflon plate by using a doctor blade. This was dried in an atmosphere of dry argon at 130 ° C. for 1 hour and then vacuum dried for 5 hours to obtain a size of 80 ×.
A positive electrode sheet composition having a thickness of 80 mm and a thickness of 160 μm was obtained.

Further, 1 part by weight of metallic aluminum powder having an average particle size of 18 μm and a purity of 99.98% was added to a polyether solution having the same composition as described above and artificial graphite having a graphitization degree of 48% and an average particle size of 2 μm. Add powder mixed with 0.1 part by weight of powder so that the solid content becomes 50%, and add 2 at 40 ° C.
The mixture was mixed for 4 hours to obtain a negative electrode slurry. An electrode composition slurry was obtained by mixing the negative electrode slurry and the electrolyte slurry having the same composition as described above for 24 hours in an alumina ball mill so that the solid content ratio was 1: 2. The electrode composition slurry was applied onto a smooth Teflon plate by using a doctor blade. This was dried in a stream of dry argon at 130 ° C. for 1 hour and further vacuum dried for 5 hours to give a size of 80 × 80 mm and a thickness of 18 mm.
A 0 μm negative electrode sheet was obtained.

A carbon sheet having a thickness of 50 μm, which is formed of a mixture mainly containing a fluororesin and carbon powder, a positive electrode sheet, an electrolyte sheet, a negative electrode sheet, and a carbon sheet (having the same composition as above) are sequentially laminated. , Temperature 150
Thermocompression bonding was performed under the conditions of ° C and pressure of 200 kg / cm ² . This was cut into a size of 28 × 28 mm to obtain a unit cell. A thickness of 30μ, which also functions as an electrode lead, via a heat-adhesive conductive film having a thickness of 10μm, which is mainly composed of synthetic rubber and carbon fiber
m copper foil was heat-bonded to both sides of the unit cell. Further, the whole unit cell was sealed with a laminate film composed of a polyethylene terephthalate film having a thickness of 38 μm, an aluminum foil having a thickness of 50 μm, and a polyethylene film having a thickness of 50 μm to obtain a battery A.

Next, as a comparison, battery B was prepared by the following method.
Was prepared. First, in acetonitrile in which 1 mol of LiBF ₄ was dissolved, electrolytic oxidation was performed at a potential of 1.0 V with respect to the potential of the Ag / AgCl electrode to obtain a disulfide compound containing no lithium ion. A battery A was prepared except that this was used in place of 2,5-dimercaptop-1,3,4-lithium thiolate, and a lithium alloy plate having an aluminum content of 30 atomic% and a thickness of 200 μm was used for the negative electrode. A battery B was obtained in the same manner as described above.

Next, another lithium battery of the present invention was prepared by the following method. 2,5-dimercaptop-1,3,4-lithium thiolate powder 1 part by weight, polyaniline powder 0.2 part by weight,
0.1 parts by weight of carbon black, 1 part by weight of LiI-Li ₃ NB ₂ O ₃ (molar ratio = 1: 1: 1) powder, and low-density polyethylene 6
A toluene solution containing wt% was mixed. The polyaniline powder is a porous polyaniline powder having an average particle diameter of 0.3 μm and a fibril structure, which is synthesized by chemically polymerizing aniline by using cupric fluoroborate as an oxidizing agent in an acidic aqueous solution. is there. The low-density polyethylene is Excellen VL-200 (trade name; density = 0.9, manufactured by Sumitomo Chemical Co., Ltd.), and when the mixture is dried, the low-density polyethylene content is 5% by volume.
Was added. Next, this solution was applied onto a 200-mesh nylon net and dried to obtain a positive electrode sheet having a size of 80 × 80 mm and a thickness of about 155 μm.

Next, LiI-Li ₃ NB ₂ O ₃ powder and a 6 wt% toluene solution of low density polyethylene were mixed so that the content of low density polyethylene when dried was 35% by volume. Next, this solution is applied onto a 200-mesh nylon net and dried to obtain a size of 80 × 8.
An electrolyte sheet having a thickness of 0 mm and a thickness of about 90 μm was obtained.

Furthermore, 1 part by weight of metallic aluminum powder
And 0.1 parts by weight of graphite powder, LiI-Li ₃N-B₂O₃Powder 0.
5 parts by weight and the same low density polyethylene tolue as above
Content of low density polyethylene when dried
Was mixed so as to be 7.5% by volume. Above metal
Minium has an average particle size of 18 μm and a purity of 99.
Using 98% metallic aluminum powder as graphite powder
Is artificial black with a graphitization degree of 90% and an average particle size of 0.6 μm.
Lead powder was used. Then add this solution to a 200 mesh screen.
Size 8 by applying on Ronnet and drying
A negative electrode sheet having a size of 0 × 80 mm and a thickness of about 190 μm was obtained.
These positive electrode sheet, electrolyte sheet, and negative electrode sheet
A battery C was obtained in the same manner as above.

Next, as a comparison, Battery D was prepared by the following method. First, a disulfide compound containing no lithium ion was obtained by electrolytically oxidizing in 1 mol of LiBF ₄ dissolved in acetonitrile at a potential of 1.0 V with respect to the potential of an Ag / AgCl electrode. This was used in place of 2,5-dimercaptop-1,3,4-lithium thiolate, and the negative electrode contained 30 atomic% of aluminum.
A battery D was obtained by the same method as that for preparing the battery C, except that a lithium alloy plate having a thickness of 200 μm was used.

Battery A, Battery B prepared in this manner,
After applying a constant voltage of 3.6 V for 17 hours at 65 ° C. to battery C and battery D, 1 μA, 10 μA, 10 at 65 ° C.
It was discharged for 3 seconds at each current of 0 μA, 500 μA, and 1 mA. The current-voltage characteristics were evaluated by recording the battery voltage at that time. The result is shown in FIG. Comparing the current-voltage characteristics of the batteries A and C with the current-voltage characteristics of the batteries B and D of the comparative example, it can be seen that the former has a smaller drop in voltage and a larger current can be obtained.

As is clear from the above description of the embodiments, in the lithium secondary battery of the present invention, a lithium thiolate compound having a sulfur-lithium ionic bond, which forms a sulfur-sulfur bond by electrolytic oxidation, and π A positive electrode mainly composed of a mixture with an electron conjugated conductive polymer is used, and a composition mainly composed of metallic aluminum or its alloy and a carbon material is used as the negative electrode. Therefore, it is possible to safely assemble the lithium secondary battery without handling chemically active metallic lithium or its alloy when assembling the battery. In the lithium secondary battery assembled in this way, by storing the battery in a discharged state, since metallic lithium is substantially absent in the battery, it does not ignite when the battery is destroyed. Further, by using the lithium battery of the present invention, a larger current can be obtained as compared with the conventional battery using metallic lithium or its alloy as the negative electrode.

(Example 8) 84 g (1 mol) of thiophene and 100
Mix with ml of carbon tetrachloride and cool to 0 ° C. To this, 5
A solution of 00 g (3.1 mol) of bromine in 300 ml of carbon tetrachloride was slowly added. After mixing all of these, carbon tetrachloride was distilled off, 15 g of sodium hydroxide was added, and the mixture was heated on a steam bath for 4 hours. The alkaline layer was separated and removed from this mixture, and the residue was dried and then distilled to obtain 1
A mixture of substituted, disubstituted and trisubstituted thiophene bromides was obtained. This mixture was dissolved in xylene and fractionated by using a silica gel column to obtain 30 g of 2,2,3-tribromothiophene.

32 g (0.1 mol) of 2,2,3 thus obtained
-Tribromothiophene and 6.5 g (0.2 mol) zinc metal and 6 g
(0.2 mol) acetic acid was mixed and reacted to obtain 3-bromothiophene.

8.0 g (0.05 mol) of 3-bromothiophene was added to 4
g of thiourea was added and reacted in acetonitrile to obtain 2 g (0.01 mol) of 3-mercaptothiophene. This 3-mercaptothiophene was reacted with 0.8 g (0.01 mol) of 1-propylmercaptan in chlorine to obtain disulfide-introduced thiophene.

Using the thiophene derivative (1 mol / l) thus obtained as a monomer, propylene carbonate was obtained.
In the solution, by using lithium perchlorate as a supporting electrolyte, the potential of the saturated calomel reference electrode was 1.
Electrolysis was performed at a constant potential of 2 to 1.5 volt. As a result, a conductive polymer containing a lithium thiolate group was obtained.

Next, an electrolyte sheet having the same composition and size as the battery A of Example 7 was prepared.

Next, an electrolyte slurry (Battery A of Example 7)
1 parts by weight, the same composition as the electrolyte slurry used to prepare the above), 0.1 part by weight of artificial graphite powder having a graphitization degree of 48% and an average particle size of 2 μm, and the above-mentioned lithium thiolate group-containing conductive material. The positive electrode slurry was obtained by mixing with 2 parts by weight of the organic polymer. This positive electrode slurry was applied onto a smooth Teflon plate by using a doctor blade. This was dried in a stream of dry argon at 130 ° C for 1 hour and further 5
80 x 80 mm in size by vacuum drying for
A positive electrode sheet having a thickness of 160 μm was obtained.

Next, a negative electrode sheet having the same composition and size as in the case of the battery A of Example 7 was prepared.

Using the above positive electrode sheet, electrolyte sheet and negative electrode sheet, a battery A of this example was prepared in the same manner as in the preparation of battery A of example 7.

Next, as a comparison, Battery B was prepared by the following method. First, a disulfide compound containing no lithium ion was obtained by electrolytically oxidizing 1 mol of LiBF4 in acetonitrile at a potential of 1.0 V with respect to the potential of an Ag / AgCl electrode. This battery A was used except that this was used instead of the above-mentioned conductive polymer containing a lithium thiolate group, and a 200 μm thick lithium alloy plate with an aluminum content of 30 atomic% was used for the negative electrode. A battery B was obtained in the same manner as in the preparation.

Next, another lithium secondary battery of the present invention was prepared by the following method. The thiophene derivative having a disulfide group synthesized above was chemically polymerized by using cupric borofluoride as an oxidizing agent in an acidic aqueous solution.
As a result, a porous thiophene derivative polymer having an average particle size of 0.3 μm and a fibril structure was synthesized. 0.2 parts by weight of this thiophene derivative polymer powder, 0.1 parts by weight of carbon black, and LiI-Li ₃ NB ₂ O ₃
(Mole ratio = 1: 1: 1) 1 part by weight of powder was mixed with a toluene solution containing 6% by weight of low-density polyethylene. The low density polyethylene was Excellen VL-200 (trade name; density = 0.9, manufactured by Sumitomo Chemical Co., Ltd.), and was added so that the content of the low density polyethylene was 5% by volume when the mixture was dried. Then, this solution is coated on a 200-mesh nylon net, and by drying it,
A positive electrode sheet having a size of 80 × 80 mm and a thickness of about 155 μm was obtained.

Next, the same electrolyte sheet and negative electrode sheet as those used when preparing the battery C of Example 7 were prepared. Using the positive electrode sheet, the electrolyte sheet and the negative electrode sheet, a battery C of this example was manufactured by the same method as described above.

Next, for comparison, battery D was prepared by the following method.
Was prepared. First, a disulfide compound containing no lithium ion was obtained by electrolytically oxidizing 1 mol of LiBF4 in acetonitrile at a potential of 1.0 V with respect to the potential of an Ag / AgCl electrode. A battery C is prepared except that this is used instead of a conductive polymer containing a lithium thiolate group and a lithium alloy plate having a thickness of 200 μm and an aluminum content of 30 atomic% is used as a negative electrode. A battery D was produced in the same manner as in.

Battery A, Battery B prepared in this way,
After applying a constant voltage of 3.6 V for 17 hours at 65 ° C. to battery C and battery D, at 65 ° C., 1 μA, 10 μA,
It was discharged for 3 seconds at each current of 100 μA, 500 μA, and 1 mA. The current-voltage characteristics were evaluated by recording the battery voltage. The result is shown in FIG. In this example, comparing the current-voltage characteristics of the batteries A and C with the current-voltage characteristics of the batteries B and D of the comparative example, it can be seen that the former has a smaller drop in voltage and a larger current can be obtained. .

[0100]

As described above, by using the electrode material of the present invention, it is not necessary to handle chemically active metallic lithium or its alloy at the time of battery assembly, so that battery assembly work is safe. Further, in the lithium secondary battery assembled in this way, no ignition occurs when the battery is destroyed.

Furthermore, by using the battery of the present invention, a larger current can be taken out as compared with the conventional battery using metallic lithium or its alloy as the negative electrode.

[Brief description of drawings]

FIG. 1 is a current-voltage characteristic diagram of a reversible electrode using the electrode material according to the first embodiment of the present invention and a conventional electrode.

FIG. 2 is a current-voltage characteristic diagram of a battery using a reversible electrode using the electrode material of the second embodiment of the present invention and a battery using a conventional electrode for the positive electrode.

FIG. 3 is a current-voltage characteristic diagram of a reversible electrode using an electrode material and a conventional electrode in a third embodiment of the present invention.

FIG. 4 is a current-voltage characteristic diagram of a reversible electrode using the electrode material of the fourth embodiment of the present invention and a conventional electrode.

FIG. 5 is a current-voltage characteristic diagram of a reversible electrode using the electrode material of the fifth embodiment of the present invention and a conventional electrode.

FIG. 6 is a current-voltage characteristic diagram of a reversible electrode using the electrode material of the sixth embodiment of the present invention and a conventional electrode.

FIG. 7 is a charge / discharge cycle characteristic diagram of a reversible electrode using the electrode material of the sixth embodiment of the present invention and a conventional electrode.

FIG. 8 is a current-voltage characteristic diagram of a lithium battery according to a seventh embodiment of the present invention and a conventional lithium battery.

FIG. 9 is a current-voltage characteristic diagram of a lithium battery according to an eighth embodiment of the present invention and a conventional lithium battery.

 ─────────────────────────────────────────────────── ─── Continuation of front page (31) Priority claim number Japanese Patent Application No. 3-35865 (32) Priority date Hei 3 (1991) March 1 (33) Country of priority claim Japan (JP) (31) Priority Claim No. Japanese Patent Application No. 3-44734 (32) Priority Date No. 3 (1991) March 11 (33) Country of priority claim Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-137415 (32) Priority Hihei 3 (1991) June 10 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 3-145856 (32) Priority Day Hei 3 (1991) June 18 (33) ) Japan in which priority is claimed (JP) (72) Inventor Yoshiko Sato 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kenichi Takeyama, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Noboru Koyama 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Katsuhiko Naoi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A combination of a compound having a disulfide group and a conductive polymer, or an electrode material having a conductive polymer having a disulfide group, wherein the S—S bond of the disulfide group is cleaved by electrolytic reduction. An electrode material in which a sulfur-metal ion bond or a sulfur-proton bond is formed, and the sulfur-metal ion bond or the sulfur-proton bond forms an S-S bond by electrolytic oxidation. 2. The electrode material according to claim 1, which has a combination of a compound having a disulfide group and a conductive polymer, wherein the compound having a disulfide group has a cleavable disulfide group in the molecule. And electrode material. 3. A conductive polymer having a disulfide group,
The electrode material according to claim 1, which is obtained by introducing a disulfide group into a π-electron conjugated conductive polymer. 4. A conductive polymer having a disulfide group,
The electrode material according to claim 1, which is capable of forming a π-electron conjugated conductive polymer and is obtained by electrolytically polymerizing a monomer having a disulfide group. 5. A step of dimerizing a compound having a thiol group to obtain a dimer having a disulfide group and a monomer capable of forming a π-electron conjugated conductive polymer in the presence of the dimer. A method for producing a reversible electrode, comprising a step of electrolytically polymerizing on an electrode substrate. 6. A lithium thiolate and a π-electron conjugated conductive polymer having a positive electrode, a solid electrolyte, and a negative electrode, the positive electrode having a sulfur-lithium ionic bond capable of forming a disulfide bond by electrolytic oxidation. A salt containing a lithium ion-bonding conductive polymer having a sulfur-lithium ion bond capable of forming a disulfide bond by electrolytic oxidation as a main component, and the solid electrolyte containing lithium. Or a lithium secondary battery characterized by comprising a composition containing a polymer containing the salt as a main component, and the negative electrode containing a composition containing aluminum or an aluminum-containing alloy and carbon as the main components. battery. 7. The lithium secondary battery according to claim 6, wherein the electrolyte is mixed with the composition forming the positive electrode or the composition forming the negative electrode. 8. A polyether 3 obtained by adding at least one selected from the group consisting of ethylene oxide and propylene oxide to a polyamine as a solid electrolyte.
And a compound having an ion-exchangeable layered crystal structure and a lithium salt represented by LiX (where X is an anion of a strong acid), the lithium secondary battery according to claim 6.