JPH0821383B2 - Secondary battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a secondary battery, and more particularly to a secondary battery in which a conductive material composed of an oxidized polymer of a specific aniline compound is used as an electrode material. .

<Related Art> In recent years, a secondary battery using a conductive polymer made of various organic materials as an electrode material has been proposed.

The conductivity of a conductive polymer used as an electrode material of a secondary battery of this kind is dramatically increased by doping with a dopant such as various anions and cations.

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 a solution containing a dopant is used as an electrolytic solution to perform doping and dedoping. A battery that can be charged and discharged is constructed by performing the chemical reversible process.

Such conductive polymers include polyacetylene,
Polypyrrole, polythiophene, polyaniline, etc. are known. Among them, particularly, research and development of an oxidation polymer of an aniline compound represented by polyaniline is active, and the characteristics of the oxidation polymer of this aniline compound are There are various suggestions for improvement.

<Problems to be Solved by the Invention> However, the oxidation polymers of aniline-based compounds that have been conventionally used are still low in conductivity, and the liquid content of the electrolytic solution is insufficient. The secondary battery using the above-mentioned oxidized polymer has a problem that satisfactory battery capacity and charge / discharge capacity efficiency cannot be obtained, and further improvement of these battery characteristics is desired.

The present invention has been made in view of the above circumstances, and by using an oxidative polymer of an aniline-based compound having improved characteristics as an electrode material, the battery capacity is large, and high charge / discharge capacity efficiency is achieved over a long cycle. An object is to provide a secondary battery that can be maintained.

<Means for Solving the Problems> The inventors of the present invention have made diligent studies on such an oxidative polymer of a specific aniline-based compound, and have found that the intended purpose can be achieved by using the following means. After knowing this, the present invention was completed.

That is, the present invention resides in a secondary battery characterized in that a conductive material obtained by treating an oxidized polymer of an aniline-based compound with an organic aliphatic carboxylic acid is used as at least one of a positive electrode and a negative electrode.

The aniline compound used in the present invention has a general formula (In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, an alkylamino group and an arylamino group, and R ³ and R ⁴ represent a hydrogen atom, an alkyl group, An aniline-based compound represented by the formula (1) represents an aryl group.

In the aniline-based compound represented by the general formula (1), R ¹ and R ² are, specifically, hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group. , Sec-butyl group, tert-butyl group,
Methoxy, ethoxy, n-propoxy, n-butoxy, phenyl, toluyl, naphthyl, phenoxy, methylphenoxy, naphthoxy, amino, dimethylamino, diethylamino, phenylamino, diphenyl Represents an amino group, a methylphenylamino group, and a phenylnaphthylamino group, and R ³ and R ⁴ represent a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a phenyl group, a toluyl group, and a naphthyl group. Represents a group.

Specific examples of such aniline compounds include aniline, methylaniline, ethylaniline, n-propylaniline, isopropylaniline, n-butylaniline,
Methoxyaniline, ethoxyaniline, n-propoxyaniline, phenylaniline, toluylaniline, naphthylaniline, phenoxyaniline, methylphenoxyaniline, naphthoxyaniline, aminoaniline, dimethylaminoaniline, diethylaminoaniline, phenylaminoaniline, diphenylaminoaniline, methyl Examples include phenylaminoaniline and phenylnaphthylaminoaniline.

Next, the organic aliphatic carboxylic acids used in the present invention will be described in detail. Examples of such organic aliphatic carboxylic acids include saturated aliphatic monocarboxylic acids, saturated aliphatic dicarboxylic acids, unsaturated aliphatic monocarboxylic acids, unsaturated aliphatic dicarboxylic acids, and the like. Examples of the saturated aliphatic monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, lauric acid, myristic acid, parsitic acid, stearic acid and the like. Examples of the saturated aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, as well as azelaic acid and sebacic acid. On the other hand, examples of unsaturated aliphatic monocarboxylic acids include acrylic acid, propiolic acid, methacrylic acid, crotonic acid, isocrotonic acid and oleic acid. Further, examples of the unsaturated aliphatic dicarboxylic acids include maleic acid and fumaric acid.

Among these organic aliphatic carboxylic acids, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, acrylic acid and the like which are liquid at room temperature are preferable.

These organic aliphatic carboxylic acids may be used alone or as a mixture of two or more kinds. Further, it is also possible to dissolve them in an organic solvent or the like that does not affect the treatment and use them in a solution state.

Next, a method for producing an oxidation polymer of an aniline compound used in the present invention will be described.

This oxidative polymer can be produced by either an electrochemical polymerization (electrolytic polymerization) method or a chemical polymerization method. In the case of the electrochemical polymerization method, the oxidative polymerization of the aniline compound is performed by anodic oxidation. The electrolytic current at that time is 0.001 to 100 mA / cm ² , and the electrolytic voltage is 0.1 to 100 V.
The constant current method, the constant voltage method, and any other method can be used. Further, this oxidative polymerization is carried out in an aqueous solution, a non-aqueous solvent such as alcohols, or a mixed solvent thereof. Further, this oxidative polymerization is carried out in the presence of an acid. Specific examples of the acid used at this time include, but are not limited to, HCl, H ₂ SO ₄ , HBF ₄ , CF ₃ COOH and HClO ₄ .

On the other hand, when the oxidative polymer of the aniline-based compound is produced by a chemical polymerization method, the aniline-based compound or a salt which is a reaction product of these compounds and an acid is oxidatively polymerized. The acid used at this time is HCl, H ₂ SO ₄ , HBF ₄ , CF ₃ COOH, HCl.
For example, but not limited to O ₄ . The oxidizing agent used in this chemical polymerization is, for example, a peroxide such as potassium persulfate or ammonium persulfate, potassium dichromate or potassium permanganate, ferric chloride or ferric perchlorate, or Examples include a system in which a dicopper compound and a nitrile compound are combined. The oxidative polymerization is carried out in an aqueous solution or a non-aqueous solution such as alcohols, nitrites, or a mixed solvent thereof.

Further, in both of the electrochemical polymerization method and the chemical polymerization method, other additives such as a conductive material may be added to the polymerization system in the presence thereof. Examples of such conductive materials include carbon black such as acetylene black, activated carbon, metal powder, and inorganic oxides. Other additives include, for example, Teflon powder, polyethylene oxide and the like.

Among the above-mentioned production methods, particularly preferable is a chemical polymerization method using an oxidizing agent in which a cupric compound and a nitrile compound are combined.

Therefore, a method for producing an oxidized polymer of an aniline compound using an oxidizing agent composed of a cupric compound and a nitrile compound will be described in detail below.

First, when reacting an aniline compound with an acid,
The amount of acid used is 0.01-10 with respect to 1 mol of the aniline compound.
It is a double mole, preferably 0.05 to 5 moles. The reaction temperature at this time is -50 to 150 ° C, preferably -20 to 1
It is 00 ° C. Reaction time is related to reaction temperature, but usually
It is 0.01 to 200 hours, preferably 0.5 to 100 hours.

Then, the aniline-based compound reacted with the acid is reacted with an oxidizing agent composed of a cupric compound and a nitrile-based compound to form an oxidized polymer. Such cupric compounds, _{specifically, Cu (BF 4) 2,} CuCl 2, Cu (ClO 4) 2, Cu (PF 6) 2, Cu (AsF 6) 2, Cu (SbF 6) _{2, Cu (C 6 H 5} SO 3) 2, Cu (CH 3 C 6 H 4 SO 3) 2, CuSO 4, Cu (CF 3 SO 3) 2, CuZrF 6, CuTiF 6, a CuSiF _6, these Is usually used as a compound with water of crystallization or as an aqueous solution.

The nitrile compound, specifically, acetonitrile,
Examples thereof include, but are not limited to, n-propionitrile, isopropionitrile, n-butyronitrile, isobutyronitrile, acrylonitrile, and adiponitrile.

Also, the amount of the cupric compound used is 0.1 to 100 times mol per 1 mol of the aniline compound or a salt thereof,
The molar amount is preferably 0.2 to 50 times.

The nitrile compound is used in coexistence with the cupric compound, and examples of its usage include the following methods.

1) A nitrile compound and a cupric compound are allowed to coexist in advance, and then an aniline compound or a salt thereof is allowed to act.

2) A cupric compound is allowed to act on a system in which an aniline compound or a salt thereof and a nitrile compound coexist.

3) A nitrile compound is allowed to act on a system in which an aniline compound or a salt thereof and a cupric compound coexist.

4) A system in which a cupric compound and a nitrile compound coexist is allowed to act on a system in which an aniline compound or a salt thereof and a nitrile compound coexist.

5) The reaction product of the cupric compound and the nitrile compound is isolated in advance, and it is reacted with the aniline compound or a salt thereof.

The amount of the nitrile compound used in these methods is 0.01 to 10,000 times mol, preferably 0.1 to 1,000 times mol, relative to 1 mol of the cupric compound.

When the nitrile compound is a liquid substance, it is used as a reaction solvent, and when it is a solid substance, an arbitrary solvent such as an alcohol solvent such as water, methanol or ethanol, tetrahydrofuran, dioxane or benzene. A general organic solvent such as toluene, toluene, dichloromethane, dichloroethane or acetic acid can be used as a reaction solvent.

The reaction temperature is -50 to 150 ° C, preferably -20 to 100
° C. The reaction time is related to the reaction temperature, but is usually 0.
It is 5 to 200 hours, preferably 1.0 to 100 hours.

The reaction product is a dark brown to black powdery substance, and in the reaction in the presence of the solvent, after the reaction is completed, the solvent is removed by a usual method, and then in the present invention, a liquid nitrile compound such as acetonitrile is used. It is preferable to wash and purify the reaction product several times with a solvent such as propionitrile and to dissolve and remove the by-produced cuprous compound so that a product having higher conductivity can be obtained.

Next, the reaction product (oxidized polymer of aniline compound)
The reaction product is washed with an organic amine compound several times in order to remove the soluble component in the organic solvent. Specific examples of the organic amine compound include, but are not limited to, pyridine, methylpyridine, and quinoline.

The amount of the organic amine compound used is 1 to 10,000 times, preferably 2 to 100 times the weight of the aniline compound polymer.
It is 0 times. When the organic amine compound is a liquid substance, it is used as a reaction solvent as it is, and when it is a solid substance, an arbitrary solvent such as alcohols such as methanol and ethanol, ethers such as tetrahydrofuran and dioxane, etc. General organic solvents such as aromatic hydrocarbons such as benzene and toluene, nitriles such as acetonitrile and propionitrile, and esters such as ethyl acetate and butyl acetate can be used. In addition, since the soluble component is not sufficiently removed with the aqueous solution of the organic amine, the aqueous solution cannot be used.

Washing temperature is -20 ~ 150 ℃, preferably -10 ℃ ~ 1
It is 00 ° C. Cleaning time is related to cleaning temperature, but is usually
It is 0.5 to 200 hours, preferably 1.0 to 100 hours.

Next, the reaction product (oxidized polymer of aniline compound)
The method of treating the organic compound with an organic aliphatic carboxylic acid will be described.

The amount of the organic aliphatic carboxylic acid used is 1 to 500 times, preferably 2 to 250 times by weight that of the oxidized polymer of the aniline compound.

When the organic aliphatic carboxylic acid is a liquid substance at room temperature, it may be used as a solvent as it is,
In addition, alcohol solvents such as methanol and ethanol,
An ether solvent such as diethyl ether, and a general organic solvent such as tetrahydrofuran, dioxane, toluene, acetonitrile, etc. can be used.

When the organic aliphatic carboxylic acid is a solid substance at room temperature, it is mixed with a liquid organic aliphatic carboxylic acid and used as a dissolved state with it, or an alcohol solvent such as methanol or ethanol, diethyl. It may be used by dissolving it in an ether solvent such as ether or a general organic solvent such as tetrahydrofuran, dioxane, toluene or acetonitrile.

The treatment temperature is -10 to 150 ° C, preferably -5 to 100
° C. Processing time is related to the processing temperature, but is usually 0.
It is 5 to 100 hours, preferably 1.0 to 50 hours.

This reaction product has conductivity as described in Examples. In the present invention, such a reaction product is formed into a required shape by a known method such as pressure molding and used as an electrode of a secondary battery. In this case, it is possible to use such a reaction product alone. And the like are preferably added. Such a thermoplastic resin can be used without any particular limitation as long as it is substantially insoluble in the electrolytic solution of the battery. Usually, those having a molecular weight of 10,000 or more are used. Specific examples include polyethylene, polypropylene,
Ethylene-propylene copolymer, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene,
Polytrifluoroethylene, polydifluoroethylene,
Ethylene tetrafluoride-perfluoroalkylvinyl ether copolymer, ethylene tetrafluoride-propylene hexafluoride copolymer, poly (ethylene trifluoride) chloride, polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymer, chlorotrifluoro Ethylene-ethylene copolymer, polyamide,
Examples include polyester, polycarbonate, and modified polyolefin.

The conductive member is a material that does not dissolve even after repeated charging and discharging, such as metals such as stainless steel, gold, platinum, nickel, copper, molybdenum, and titanium, carbon, and the like.
There is no particular limitation as long as it is made of a member such as carbon fiber, but a lightweight and highly conductive material is particularly preferable. Specific examples include a metal net made of such a metal, a metal plated fiber, a metal vapor-deposited fiber, a metal-containing synthetic fiber, and a net, a woven fabric and a non-woven fabric made of carbon fiber, carbon composite fiber and the like. .

The amount of such thermoplastic resin and conductive member added is 100 parts by weight of the reaction product (conductive material).
It is preferable to use 0.02 to 1000 parts by weight and 2 to 100 parts by weight of the conductive member.

In the secondary battery of the present invention, an electrode formed by using such a reaction product as an electrode material is used for both positive and negative electrodes, and this electrode is used for only one electrode, and the other electrode is made of metal or metal. In some cases, an oxide or other inorganic compound, or a known conductive polymer other than the reaction product of the present invention, an organic compound, an organometallic compound, or the like is used as an electrode material. Using an electrode using this reaction product only for the positive electrode,
Taking the case of using a metal as the electrode material of the negative electrode, it is preferable to use one having an electronegativity of 1.6 or less as the metal constituting the negative electrode, and examples of such a metal include Li, Na, K, Mg, Al or their alloys, etc.
i and Li alloys are preferred.

On the other hand, as the electrolytic solution used in the secondary battery of the present invention, for example, a solution in which an electrolyte is dissolved in an organic solvent is used. 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,
An oxonium ion etc. are mentioned. As the _{^{anion, BF 4 -, ClO 4 -}} , PF 6 -, AsF 6 -, CF 3 SO 3 -, I -, B
r ^-, Cl ^-, F ^-, and the like. Specific examples of such an electrolyte include lithium tetrafluoroborate (LiBF ₄ ), lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrachloroaluminate (LiAlCl ₄ ). , Tetraethylammonium tetrafluoroborate (Et ₄ NBF ₄ ), tetra-perchlorate tetra-
Examples include but are not limited to butylammonium (nBu ₄ NClO ₄ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium iodide (LiI), lithium bromide (LiBr), and the like. . Then, using the conductive material of the present invention for both the positive and negative electrodes, and taking as an example a battery configured using an electrolytic solution obtained by dissolving LiBF ₄ as an electrolyte, during charging, the conductive material in the positive electrode is BF
₄ ⁻ , and the conductive material in the negative electrode is doped with Li ⁺ in the electrolytic solution, respectively. On the other hand, during discharge, BF ₄ ⁻ and Li ⁺ doped in the positive and negative electrodes are released into the electrolytic solution, respectively.

As the organic solvent for dissolving the electrolyte, an aprotic solvent having a high dielectric constant is preferable, and a nitrile, carbonate, ether, nitro compound, amide, sulfur-containing compound, chlorinated hydrocarbon, ketone, ester, or the like is preferably used. Can be. Further, such solvents may be used as a mixture of two or more kinds. As typical examples of these, acetonitrile, propionitrile, butyronitrile, benzonitrile, propylene carbonate, ethylene carbonate, tetrahydrofuran, dioxolane, 1,4-dioxane, nitromethane, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, 1,2 -Dichloroethane, γ-butyrolactone, 1,2-dimethoxyethane, methyl phosphate, ethyl phosphate and the like,
It is not limited to these.

The concentration of the electrolytic solution of the present invention is usually 0.001 to 10 mol / day, preferably 0.1 to 3 mol / day.

Such an electrolytic solution may be used not only by injecting it but also by impregnating the electrode using the conductive material of the present invention in advance.

In the above, the method of forming the electrode as it is without performing the doping treatment on the conductive material has been described.However, the conductive material is previously doped with a dopant, and thereafter, alone or together with the conductive member and / or the above-described conductive member. It is also possible to use a plastic resin by molding it into an electrode.

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

In the battery of the present invention, a glass filter paper, a porous membrane of Teflon, polyethylene, polypropylene, nylon or the like may be used as the separator.

<Operation> By treating with an organic aliphatic carboxylic acid as in the present invention, the electrical conductivity of the oxidized polymer of the aniline-based compound is remarkably improved as compared with the case where it is not treated, and the oxidized polymer is also improved. In, the number of pores with a large radius increases.

By using the oxidized polymer of the aniline-based compound having good electrical conductivity for the electrode of the secondary battery, the voltage increase during charging can be suppressed to a small level, and the secondary solution such as decomposition of the electrolytic solution caused by the voltage increase can be suppressed. As a result of the reaction being suppressed, the electromagnetic charge / discharge capacity efficiency is improved and the cycle characteristics are improved.

Further, by increasing the number of pores having a large radius in the oxide polymer in this manner, the liquid content of the electrolytic solution is increased, and thus the utilization rate of the oxide polymer is improved, and the charge / discharge capacity per unit weight is increased. And battery capacity can be increased.

<Example> Hereinafter, the present invention will be described specifically with reference to examples.

Production Example 1 of Conductive Material Into a round-bottomed flask of 11 was placed 9.3 g (0.1 mol) of aniline, and while stirring in a nitrogen atmosphere, a 42% HBF ₄ aqueous solution was added thereto under ice cooling (0 to 5 ° C.). 20.9 g (0.1 mol) was added dropwise over 10 minutes.

Exotherm was observed with the dropping, and after the reaction became cloudy, a powdery solid substance was deposited in the reaction solution to give a slurry form. After continuing stirring for 30 minutes, a mixed solution (oxidizing agent) of 52.7 g (0.1 mol) of 45% Cu (BF ₄ ) ₂ aqueous solution preliminarily adjusted at room temperature (15 to 20 ° C.) and 60 g of acetonitrile was added. Dropwise over 15 minutes.

A small amount of heat was observed with dropping, the reaction liquid immediately turned black, and powdery solid matter was deposited in the post-reaction liquid to give a slurry form. After continuing stirring for 4 hours, the mixture was left overnight at room temperature.

Then, when the reaction product was separated, a black powdery substance mixed with a white crystalline substance was obtained. When this was washed 3 times with 300 ml of acetonitrile, the white crystalline substance was removed by this operation.

Next, this black powdery substance was washed three times each at room temperature with 300 g of pyridine for 30 minutes with stirring, and then washed with 300 ml of acetonitrile to remove pyridine from the obtained black powdery substance. did. Then temperature 6
After drying under reduced pressure at 0 ° C., 3.0 g of a black powdery substance was obtained.

3.0 g of this black powdery substance was treated at room temperature with a mixed solution of 50 g of formic acid and 100 ml of ethanol for 2 hours, and then washed with 100 ml of ethanol. Then, when dried under reduced pressure at a temperature of 60 ° C., 3.0 g of a black powdery substance was obtained. Elemental analysis of this black powdery substance showed that C74.21%, H4.63%, N1
It was found to be 4.49% and F5.36%, which correspond to C _6.00 , H _4.50 , N _1.00 and F _0.28 assuming that carbon is 6.

The electrical conductivity of this black powdery substance was measured by the two-terminal method. As a result, 6.3 × 10 ^-6 Scm ^-1 was obtained, which proved to be an organic semiconductor having conductivity in the semiconductor region. .

The measurement of the electric conductivity was performed as follows. First, the black powdery substance obtained by the above treatment was pulverized in a mortar to a sufficiently fine size, and then pressure-molded into a disc having a diameter of 10 mm (1
Ton / cm ²⁾ was. Next, this disk sample is sandwiched between two copper cylinders of the same size, 1.2 kg of weight is applied from the top, and the lead wires are taken out from the upper and lower copper cylinders and connected to a digital multimeter (Takedariken TR 6851). The electrical conductivity of the disk sample was measured with a meter.

Next, the specific surface area of the black-colored material molded in this way, the distribution of the pore radius, respectively, when measured by a nitrogen adsorption method, mercury porosimetry, the specific surface area is 13 m ² / g, the distribution of the pore radius is It was 20 to 1000Å, and especially 60% of the pores had a radius of 100Å or more.

Comparative Example of Conductive Material 1. Reaction was performed in the same manner as in Production Example 1 above, and the reaction product was similarly washed with acetonitrile, pyridine and acetonitrile, and then dried under reduced pressure at 60 ° C. to obtain polyaniline. .

When this polyaniline was molded in the same manner as in Production Example 1 and the electric conductivity was measured, it was 9.8 × 10 ^-8 Scm ^-1 .

The distribution of specific surface area and pore radius is 13 m ² / g,
It was 20 to 1000Å, and in particular, 45% of the pores had a radius of 100Å or more.

From the above results, it can be seen that by treating an oxidized polymer of an aniline-based compound with an organic aliphatic carboxylic acid, the electrical conductivity of this oxidized polymer increases and the number of pores with a large radius increases. confirmed.

Production Example of Conductive Material 2. An experiment was conducted in the same manner as in Production Example 1 except that 100 g of propionic acid was used instead of formic acid.
0 g was obtained.

The electric conductivity of this material was 4.5 × 10 ^-6 Scm ^-1 . The specific surface area and pore distribution are 13 m ² / g and 20 to 1000, respectively.
Å, especially pores with a radius of 100 Å or more
It was 6%.

Manufacturing Example of Conductive Material 3. Ortho-toluidine 10.7 g (0.1 mol) instead of aniline
l), 37% HCl aqueous solution instead of HBF ₄ aqueous solution 9.9g (0.1mo
l), Production Example 1 except that 150 g of acetic acid was used instead of formic acid, and 0.5 g of acetylene black was allowed to coexist when an oxidizing agent was further reacted.
When the reaction operation was performed in the same manner as in 3., a black powdery substance 3.
8 g was obtained.

The electric conductivity of this material is 9.8 × 10 ^-6 Scm ^-1 , the specific surface area and the distribution of the pore radius are 14 m ² / g, 20 ~ 1500 Å, especially the pores with a radius of 100 Å or more are the whole. 51% of
Met.

Production Example of Conductive Material 4.1 In a round bottom flask, 12.3 g of ortho-anisidine was added.
(0.1 mol) was taken, and while stirring in a nitrogen atmosphere, under ice-cooling (0-5 ° C.), 16.7 g of a 42% HClO ₄ aqueous solution was added.
(0.1 mol) and 100 ml of distilled water were added over 10 minutes.

In this, ferric perchlorate hexahydrate 46.2g (0.1mol)
Was dissolved in 100 ml of distilled water and 16.7 g (0.1 ml) of 60% HClO ₄ aqueous solution, and the mixture was added dropwise over 30 minutes. Then 15
After stirring at ℃ for 3 hours, it was left overnight at room temperature (25 ℃).

Thereafter, the reaction product was separated, and the washing treatment with 300 ml of distilled water for 30 minutes each was repeated three times.

After that, it was washed with acetonitrile, pyridine and acetonitrile in the same manner as in Production Example 1. This black powdery substance is treated with 200 g of formic acid, washed with acetonitrile and again at 60 ° C.
When dried under reduced pressure in, 5.0 g of a black powdery substance was obtained.

The electric conductivity of this substance is 2.4 × 10 ^-7 Scm ^-1 , the specific surface area and the distribution of pores are 13 m ² / g and 20 to 1000 Å, especially the pores with a radius of 100 Å or more are the whole. Was 50%.

Example of production of conductive material 5. Distilled water, HBF ₄ and aniline were added to a glass container, and HB was added.
The concentration of F ₄ was adjusted to 2.0 mol and the concentration of aniline was adjusted to 0.5 mol.

Two suspension nets (SUS-316,400 mesh) of 1 cm ² each were charged into this aqueous solution at intervals of 1 cm, and electrolysis was performed at a constant current of 2 mA for 7 hours. At this time, a black substance was deposited on the anode. The black powdery substance obtained from the anode was taken and washed with 50 ml of distilled water for 30 minutes and repeated three times.

After this, washing with 100 ml of acetonitrile and 100 g of pyridine was repeated three times for 30 minutes each. This black powdery substance was immersed in 6 g of propionic acid for 24 hours, washed with methanol, and dried under reduced pressure at 60 ° C. to obtain 30 mg of a black powdery substance.

The electric conductivity of this substance is 4.1 × 10 ^-6 Scm ^-1 , the distribution of specific surface area and pore radius is 10 m ² / g, 20 ~ 800 Å, especially the pores with a radius of 100 Å or more are the whole. 60% of
Met.

Battery Example Using the conductive material obtained in Production Example 1 above as a positive electrode material,
This was mixed with acetylene black (conducting agent) and polytetrafluoroethylene (binder) at a weight ratio of 85: 10: 5, and then pressure-molded into a disk shape to obtain a positive electrode. In addition, lithium was punched into a predetermined size to form a negative electrode.

Then, as shown in the accompanying drawings, a negative electrode portion obtained by pressing the negative electrode 2 onto the bottom surface of the negative electrode can 7 via the negative electrode current collector 8 and the positive electrode 1 via the positive electrode current collector 6 to the positive electrode. Can 5
And a positive electrode portion that is in close contact with the bottom surface of the sheet through a separator 3 made of polypropylene nonwoven fabric,
A battery according to the present invention (Battery A of the present invention) was produced using an electrolytic solution obtained by dissolving lithium borofluoride (electrolyte) in propylene carbonate (solvent). In addition, in FIG.
Is an insulating gasket.

Further, the conductive materials obtained in the above Production Examples 2, 3, 4 and 5 were used as positive electrode materials, respectively, and these, acetylene black, and polytetrafluoroethylene were used in a weight ratio of 85: 1.
Batteries according to the present invention (invention batteries B, C, D and E) were prepared in the same manner as battery A of the present invention, except that the mixture was mixed at a ratio of 0: 5 and pressure-molded into a disk shape as the positive electrode. Each was produced.

On the other hand, the conductive material obtained in Comparative Example 1 was used as a positive electrode material, which was mixed with acetylene black and polytetrafluoroethylene at a weight ratio of 85: 10: 5 and pressure-molded into a disk shape. A battery for comparison (comparative battery F) was produced in the same manner as battery A of the present invention except for the positive electrode.

A charging / discharging cycle test was performed on the above six batteries, in which they were charged at a constant current of 1 mA until the battery voltage reached 4.0 V, and then discharged at a constant current of 1 mA until the battery voltage reached 2.5 V. Table 1 shows the discharge capacity of each battery in the 20th cycle of this charge / discharge test.

As shown in Table 1, the batteries A, B, C, D and E of the present invention are 7.60mAh
The capacity of Comparative Battery F was 5.80 mAh, while the capacity was high at ˜8.90 mAh.

Considering this reason, all of the conductive materials used as the positive electrode materials of the batteries A to E of the present invention were treated with an organic aliphatic carboxylic acid to increase the number of pores having a large radius. Therefore, it is considered that the charge / discharge capacity per unit weight was larger than that of the comparative battery F using the untreated conductive material as the positive electrode material, and the battery capacity was increased.

Next, a charge-discharge cycle test was performed in which the above 6 electrons were charged at a constant current of 1 mA for 8 hours and discharged at a constant current of 1 mA until the battery voltage reached 2.5V. Table 2 shows the charge end voltage (voltage at the end of charge) and charge / discharge capacity efficiency of each battery in the 100th cycle of this test.

It can be seen from Table 2 that the batteries A to E of the present invention show a smaller increase in battery voltage during charging and a higher charge / discharge capacity efficiency than the comparative battery F.

The charging / discharging capacity efficiency of the comparative battery F is as low as 86%, because the voltage increase during charging is large, which causes the decomposition of the electrolyte solvent or solute, the corrosion of the battery can and the current collector material, and the deterioration of the conductive material itself. It is thought that the cause is.

On the other hand, in the case of the battery of the present invention, since the conductive material having a large electric conductivity and the positive electrode were used, the voltage increase during charging was small, and therefore the above-mentioned side reactions hardly occur, resulting in good battery characteristics. It is thought that this can be maintained.

In the above, the battery using the conductive material only as the positive electrode material has been described, but it is clear that the same effect can be obtained when the conductive material according to the present invention is used as the negative electrode material or the positive and negative electrode material.

<Effects of the Invention> According to the secondary battery of the present invention configured as described above, since the charge / discharge capacity per unit weight of the electrode is increased, the battery capacity can be increased, and the electrical conductivity of the electrode can be improved. With the accompanying improvement in charge / discharge capacity efficiency, it is possible to improve battery characteristics such as charge / discharge cycle life.

[Brief description of drawings]

The accompanying drawings are cross-sectional views showing a battery structure according to an embodiment of the present invention. 1 ... Positive electrode, 2 ... Negative electrode, 3 ... Separator, 5 ... Positive electrode can, 7 ... Negative electrode can.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Ando 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryoh Chemical Industry Co., Ltd. Research Institute Address Sanyo Electric Co., Ltd. (72) Inventor Koji Nishio 2-18 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (5)

[Claims] 1. A conductive material obtained by treating an oxidized polymer of an aniline compound with an organic aliphatic carboxylic acid,
A secondary battery, which is used as at least one of a positive electrode and a negative electrode. 2. The aniline-based compound has the general formula (In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, an alkylamino group and an arylamino group, and R ³ and R ⁴ represent a hydrogen atom, an alkyl group, The secondary battery according to claim 1, which is an aniline-based compound represented by an aryl group. 3. The organic aliphatic carboxylic acids are saturated aliphatic monocarboxylic acids, saturated aliphatic dicarboxylic acids, unsaturated aliphatic monocarboxylic acids, unsaturated aliphatic dicarboxylic acids. The secondary battery according to item 1. 4. The secondary battery according to claim 1, wherein the oxidative polymer of the aniline-based compound is obtained by electrochemically polymerizing the aniline-based compound. 5. The aniline-based compound oxidation polymer is characterized in that the aniline-based compound or a salt which is a reaction product of these compounds and an acid is treated with an oxidizing agent. The secondary battery according to item 1 above.