JPH06200018A - Polyaminoazothiophene and its production - Google Patents

Abstract

PURPOSE:To obtain a polyaminoazothiophene excellent in stability, conductivity, etc., and useful as a positive electrode active substance for a secondary battery by polymerizing 5,5'-diamino-2,2'-azothiophene through oxidation with an oxidizing agent in an organic solvent. CONSTITUTION:A polyaminoazothiophene of formula I (wherein n is 5-10000) is obtained by polymerizing 5,5'-diamino-2,2'-azothiophene or its hydrochloride through chemical oxidation in the presence of an oxidizing agent (e.g. sodium perborate) in an organic solvent (e.g. methanol). An anion-doped polyaminoazothiophene of formula II wherein a is 1, 2 or 3; m is 0.01-3; and X<-a> is an anion can be produced by molding the polyaminoazothiophenene powder into a pellet, attaching a lead wire to this pellet to make an electrode, and subjecting this electrode to electrolytic oxidation in a solution containing an anion source as a supporting electrolyte.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel polyaminoazothiophene, a method for producing the same, and a secondary battery using the polyaminoazothiophene as a positive electrode active material.

[0002]

2. Description of the Related Art In recent years, miniaturization of electronic devices has progressed, and along with this, there has been a demand for development of batteries that are lightweight and exhibit excellent characteristics. Conductive polymers have attracted attention as electrode active materials for such batteries, and many conductive polymers such as polyaniline, polypyrrole, and polythiophene have been developed so far. These polymers are generally synthesized from monomers by electrolytic oxidative polymerization or chemical oxidative polymerization. To date, the starting materials for conductive polymer materials have been polyaniline,
Since most of them are pyrrole, thiophene and their derivatives, in polymers other than polyaniline containing a nitrogen atom, the conjugated structure of the polymer main chain is composed of carbon-carbon double bonds. It has been considered to improve stability and conductivity by introducing an azo group as a new structural component into the main chain conjugated system composed of such a carbon-carbon double bond. Although azophenylene has been synthesized, it has not yet exhibited the performance superior to that of the carbon-carbon double bond material.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel conductive polymer having an azo group in its main chain and excellent in stability and conductivity.

Another object of the present invention is to provide a battery which uses such a novel conductive polymer and is lightweight and exhibits excellent characteristics.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor succeeded in synthesizing a polyaminoazothiophene having a novel structure, which was a conductive polymer. As a result, they have found that they are useful as positive electrode active materials for secondary batteries.

That is, the present invention provides the following inventions: General formula (1)

[0007]

[Chemical 8]

A polyaminoazothiophene represented by the formula (n represents an integer of 5 to 10000).

2. General formula (2)

[0010]

[Chemical 9]

(In the formula, n represents an integer of 5 to 10000; m is 0.01 to 2; a is 1, 2 or 3; X- ^a is an anion) Ion-doped polyaminoazothiophene.

3. 5,5′-diamino-2,2′-azothiophene or its hydrochloride is oxidized in an organic solvent in the presence of an oxidizing agent, the general formula (1)

[0013]

[Chemical 10]

A method for producing a polyaminoazothiophene represented by the formula (n represents an integer of 5 to 10000).

4. General formula (1)

[0016]

[Chemical 11]

A general formula (2) characterized by oxidizing a polyaminoazothiophene represented by the formula (n represents an integer of 5 to 10000)

[0018]

[Chemical 12]

(In the formula, n represents an integer of 5 to 10,000; m is 0.01 to 2; a is 1, 2 or 3; X- ^a is an anion) Method for producing ion-doped polyaminoazothiophene.

5. General formula (1)

[0021]

[Chemical 13]

(Wherein n represents an integer of 5 to 10000) or a polyaminoazothiophene represented by the general formula (2)

[0023]

[Chemical 14]

(Wherein n represents an integer of 5 to 10000; m is 0.01 to 2; a is 1, 2 or 3; X- ^a is an anion) A secondary battery using ion-doped polyaminoazothiophene as a positive electrode active material.

In the polyaminoazothiophene of the present invention represented by the general formula (1), the value of n is usually 5 to 1000.
It is an integer of 0, and more preferably an integer of 10 to 1000.

In the polyaminoazothiophene doped with an anion represented by the general formula (2), the value of n is usually about 5 to 10000, and more preferably about 10 to 1000. In the polyaminoazothiophene doped with an anion represented by the general formula (2), the value of m is usually in the range of 0.001 to 2, and preferably in the range of 0.01 to 1. a
The value of is an integer of 1 to 3, more preferably 1.

In the polyaminoazothiophene of the present invention represented by the general formula (2) doped with anion,
As the anion represented by X- ^a , inorganic ions such as perchlorate ion, tetrafluoroborate ion, fluoroarsenate ion, sulfate ion, and iron chloride ion; p-toluenesulfonate ion, trifluoromethanesulfonate ion Examples thereof include organic acid ions such as; and halogen ions such as fluorine ion, chlorine ion, bromine ion, and iodine ion.

The polyaminoazothiophene represented by the general formula (1) is, for example, 5,5 'represented by the general formula (1).
-Diamino-2,2'-azothiophene or its hydrochloride can be obtained by subjecting it to chemical oxidative polymerization in the presence of an oxidizing agent.

As the polymerization solvent, 5,5'-diamino-
The one that dissolves 2,2'-azothiophene is used,
Specifically, alcohols such as methanol, ethanol and isopropanol, organic acids such as glacial acetic acid and formic acid, inorganic acids such as hydrochloric acid and sulfuric acid, dimethyl sulfoxide, dimethylformamide, pyrrolidone, N-methylpyrrolidone,
Examples include pyridine and water. You may use these in mixture of 2 or more types. Among these solvents, methanol, acetic acid, water and the like are more preferable. In the polymerization, a solution having a 5,5′-diamino-2,2′-azothiophene concentration of about 0.01 to 1 mol / liter, more preferably about 0.1 to 0.5 mol / liter is used. .

As the oxidizing agent in this chemical oxidative polymerization,
Sodium perborate, a mixture of sodium perborate and boric acid, etc. are used. The amount of sodium perborate used is usually about 2 to 10 times (molar ratio) of 5,5'-diamino-2,2'-azothiophene, more preferably 2 to 5 times.
It is about double. When boric acid is used in combination, it is used in a proportion of about 0.5 to 2 times (molar ratio), and more preferably about 0.5 to 1 times that of sodium perborate.

The polymerization reaction is not particularly limited, but is usually performed at a temperature of about 20 to 80 ° C. for about 0.5 to 16 hours, more preferably at about 40 to 60 ° C. for about 2 to 6 hours. To do.

By the above reaction, polyaminoazothiophene represented by the general formula (1) is obtained as a black powder, which is purified by washing with a solvent if necessary.

The anion-doped polyaminoazothiophene represented by the general formula (2) can be obtained by, for example, molding the polyaminoazothiophene powder represented by the general formula (1) obtained as described above into pellets. , A lead wire is attached, an electrode is produced, and then the electrode is subjected to electrolytic oxidation treatment in a solution containing an anion source as a supporting electrolyte.

As the anion source as the supporting electrolyte,
Perchloric acid and its salts corresponding to the above-mentioned ions, tetrafluoroboric acid and its salts, fluoroarsenic acid and its salts, sulfuric acid and its salts, iron chloride; p-toluenesulfonic acid and its salts, trifluoromethanesulfonic acid and Examples thereof include organic acids such as salts thereof and salts thereof; halogen compounds such as fluorine compounds, chlorine compounds, bromine compounds and iodine compounds. The solvent used for the electrolytic oxidation treatment for this doping is preferably one that dissolves the supporting electrolyte as an anion source well, and specifically, alcohols such as methanol, ethanol, and isopropanol; tetrahydrofuran, dioxane, dimethylethylene glycol. And the like; carbonates such as propylene carbonate, ethylene carbonate, and diethyl carbonate; nitro compounds such as nitrobenzene and nitromethane; and other acetonitrile, dimethylformamide, dimethylsulfoxide, hexamethylphosphoramide, and the like. Among these solvents, acetonitrile, propylene carbonate and tetrahydrofuran are more preferable. The concentration of the supporting electrolyte in the solvent is usually about 0.01 to 1 mol / liter, more preferably about 0.05 to 0.5 mol / liter.

The electrolytic oxidation for the anion doping may be carried out by any of the constant current method, the constant potential method, the potential scanning method and the like. For example, the current density in the constant current method is about 0.01 to 10 mA / cm ² ,
More preferably, it is about 0.1 to 1 mA / cm ² . The potential in the potentiostatic method is usually about 0.1 to V, more preferably about 0.2 to 0.6 V (vs. Ag / Ag.
⁺ ).

The polyaminoazothiophene of the present invention doped with an anion represented by the general formula (2) is 5,5
It can also be obtained by electropolymerizing ′ -diamino-2,2′-azothiophene in an electrolytic solution containing a supporting electrolyte.

On the contrary, the polyaminoazothiophene represented by the general formula (1) can also be obtained by electrolytically reducing the anion-doped polyaminoazothiophene represented by the general formula (2). This reduction reaction is performed, for example, by reducing under a constant current of about 0.1 to 1 mA / cm ² until the working electrode shows about −0.6 to −0.1 V with respect to Ag / AgCl. .

As a battery using the polyaminoazothiophene of the present invention as a positive electrode active material, various secondary batteries can be mentioned. Other constituent materials such as the negative electrode active material and the electrolytic solution in such a battery may be the same as the known constituent materials in the battery. As the negative electrode active material in the polymer secondary battery, polyacetylene, polyparaphenylene,
Conductive polymers such as polypyridine and carbon materials can be used. As a negative electrode active material in a lithium secondary battery, L
Examples thereof include alloys of i or Li and Al, Mg, Pb, Si, Ga, In or the like. As the electrolytic solution, a solution in which a known electrolyte is dissolved in an organic solvent is used. Examples of the electrolyte include salts with metal cations, cations such as organic cations, and anions. Examples of cations include quaternary ammonium ions.
Further, as anions, BF ₄ ⁻ , ClO ₄ ⁻ , PF ₆ ⁻ ,
As ₆ ⁻ , CF ₃ SO ₃ ⁻ , I ⁻ , Br ⁻ , Cl ⁻ , F ⁻ . Specific examples of such an electrolyte include lithium tetrafluoroborate, lithium perchlorate, lithium hexafluorophosphate, tetraethylammonium tetrafluoroborate, tetra-n-butylammonium perchlorate, lithium trifluoromethanesulfonate, and iodine. Examples thereof include lithium bromide and lithium bromide.

As the organic solvent for dissolving the electrolyte, those having high conductivity and aprotic property are preferable, and nitriles, carbonates, ethers, nitro compounds, amides, sulfur-containing compounds, chlorinated carbon compounds are preferable. , Ketones,
Esters and the like can be used. You may use these organic solvents in mixture of 2 or more types. More preferable specific examples of the organic solvent include acetonitrile, propylene carbonate, tetrahydrofuran, dioxane, nitromethane, N, N-dimethylformamide, dimethyl sulfoxide, 1,2-dichloroethane, γ-butyrolactone and the like.

Inorganic and organic solid electrolytes can also be used as the electrolyte. Examples of the inorganic solid electrolyte include metal halides such as AgCl, AgBr, AgI and LiI, RbAg ₄ I ₅ and RbAg ₄ I ₄ N. Examples of the organic solid electrolyte include a polymer electrolyte such as polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, polyacrylamide, and the like, in which the above-mentioned electrolytic salt is dissolved in a polymer matrix, or a cross-linked body of these composites. .

[0041]

The polyaminoazothiophene of the present invention is
Since it is electrochemically active and highly stable, it is possible to obtain a secondary battery that is lightweight and exhibits excellent characteristics by using it.

[0042]

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 5,5'-diamino-azothiophene dihydrochloride 0.3 in a three-necked flask equipped with a stirrer, a condenser and a thermometer.
0 g, sodium perborate tetrahydrate 0.47 g, boric acid 0.12 g and methanol 5 cc were added to prepare a solution, which was then reacted at 50 ° C. for 6 hours under stirring. After completion of the reaction, the reaction solution was suction filtered to obtain a black solid. The solid was thoroughly washed with boiling water and further with methanol. The product was dried under reduced pressure at 100 ° C. for 5 hours to obtain 0.14 g of polyaminoazothiophene.

The FT-IR data of the product obtained above is shown below.

FT-IR (KBr) ν (cm ^-1 ): 33
44, 3192, 1668, 1612, 1438, 14
13,1205,1129,1040,983,79
Table 1 shows the elemental analysis values of the obtained products.

[0046]

[Table 1]

From the elemental analysis values shown in Table 1, the result of carbon / nitrogen (molar ratio) = 2.67 (theoretical value 2.67) was obtained, and this product was aminoazo which is the target substance. It was confirmed to be a polymer having thiophene as a repeating unit.

The following analytical instruments were used.

IR: Nicolet 20SXC type Elemental analysis: PERKIN ELMER 2400 Example 2 Polyaminoazothiophene obtained in the same manner as in Example 1 was molded into pellets using acetylene black as a conductive additive, and further formed into a stainless steel mesh. The electrodes were sandwiched and electrodes were prepared.

The obtained electrode was immersed in an acetonitrile solution containing 0.1 M LiClO ₄ and then 0.5 V (vs.
X = Cl by performing potentiostatic oxidation with Ag / Ag ⁺ ).
A polymer represented by the general formula (2) which is O ₄ ⁻ was obtained.

Example 3 The electrode obtained in the same manner as in Example 2 was immersed in a methanol solution containing 0.1 M p-toluenesulfonic acid, and
A polymer represented by the general formula (2) having X = TsO ⁻ was obtained by performing potentiostatic oxidation at 5 V (vsAg / Ag ⁺ ).

[0052] By the electrode obtained in the same manner as in Example 4 Example 2 is immersed in hydrochloric acid solution, X = Cl ^- to give a polymer represented by a is Formula (2).

Reference Example 1 An electrode obtained in the same manner as in Example 2 was treated with 0.1 M LiClO ₄
Dipped in an acetonitrile solution containing -1.5-1.
As a result of scanning the potential at 0 V (vs Ag / AgCl) and 0.1 V / sec, a redox peak was observed at around 0.2 V, and it was found that the polymer according to the present invention can be used as an electrode active material in a secondary battery. did.

Front page continuation (72) Inventor Kenji Seki, 1-2-2 Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Osaka Gas Co., Ltd.

Claims (5)

[Claims] 1. A general formula (1): (In formula, n shows the integer of 5-10,000) Polyaminoazo thiophene shown. 2. A general formula (2): (In the formula, n represents an integer of 5 to 10000; m represents 0.0
1 to 2; a is 1, 2 or 3; X- ^a represents an anion), and polyaminoazothiophene doped with an anion. 3. A compound represented by the general formula (1): wherein 5,5'-diamino-2,2'-azothiophene or its hydrochloride is oxidized in an organic solvent in the presence of an oxidizing agent. (In formula, n shows the integer of 5-10,000) The manufacturing method of polyamino azothiophene shown by these. 4. General formula (1): (Wherein n represents an integer of 5 to 10000), polyaminoazothiophene represented by the general formula (2): (In the formula, n represents an integer of 5 to 10000; m represents 0.0
1 to 2; a is 1, 2 or 3; X- ^a represents an anion), and a method for producing a polyaminoazothiophene doped with an anion. 5. A compound represented by the general formula (1): (In the formula, n represents an integer of 5 to 10,000) or a polyaminoazothiophene represented by the general formula (2): (In the formula, n represents an integer of 5 to 10000; m represents 0.0
1 to 2; a is 1, 2 or 3; X ^−a represents an anion), and a secondary battery characterized by using a polyaminoazothiophene doped with an anion as a positive electrode active material. .