JPH051306B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a composition comprising an adduct between a polymer capable of forming a complex adduct with iodine and iodine, and/or a composition in which iodine is dispersed in a polymer capable of forming a complex adduct with iodine. The present invention relates to a conductive resin composition in which carbon is dispersed in a material.

Iodine is a substance that easily becomes an anion and is one of the materials suitable as a positive electrode active material.

This iodine is known to form charge transfer complexes with various organic compounds. Iodine charge transfer complexes consist of iodine (acceptor) and various electron-donating compounds (organic donor components). Examples of electron-donating compounds include heterocycles such as phenothiazine and carbazole; polycyclic aromatic compounds such as pyrene perylene; 2-vinylpyridine, polyvinylpyrrolidone, polyacrylonitrile, polyethylene,
polypropylene, polymethyl methacrylate,
Polystyrene, polyamide, polyurethane, polyvinyl alcohol, polyacrylamide, polyether, polyacetylene, polyparaphenylene,
Organic polymers such as polypyrrole and polyaniline are known.

Each of these charge transfer complexes exhibits a significant increase in conductivity compared to the original simple substance.

Among these, poly-2-vinylpyridine-iodine complexes have been put into practical use as positive electrode mixtures for lithium batteries. On the other hand, in recent years, polyacetylene, polypyrrole, polyaniline, polyparaphenylene, and the like have been actively developed as conductive compounds. It is known that the electrical conductivity of these compounds is increased by doping them with iodine. However, it has various problems such as being easily oxidized by oxygen and the like, being unstable, and having poor workability.

In particular, when these charge transfer complexes are used as a positive electrode mixture for a battery, the positive electrode mixture gradually loses its conductivity because iodine is released as it is discharged. For this reason, as discharge progresses, the resistance of the positive electrode mixture increases significantly, resulting in a significant decrease in the electromotive force of the battery.

In addition, when a positive electrode mixture made of this charge transfer complex is used in a secondary battery, most of the iodine is released from the positive electrode mixture during discharge, so the positive electrode mixture usually becomes an insulator and cannot be charged again. As a secondary battery that is said to be possible, it has a decisive drawback. This is a problem that inevitably occurs when using iodine complexes of polymers that are inherently insulating, such as polyamide, polyacrylonitrile, polyvinyl alcohol, polyether, and poly-2-vinylpyridine.

The present inventors have made intensive studies to overcome the drawbacks of such charge transfer complexes, and as a result, they have been able to overcome the above drawbacks by creating a composition in which carbon is added to the complex positive electrode mixture, and these drawbacks include, for example, ,
The present invention was completed based on the discovery that an excellent battery can be provided when the present invention is used as a positive electrode mixture for a battery. That is, the present invention provides an iodine-containing conductive material in which carbon is dispersed in a complex adduct of iodine and a polymer capable of forming a complex adduct, and/or a composition in which iodine is dispersed in the polymer. A resin composition is provided.

In the present invention, polymers capable of forming complex adducts with iodine include polyacrylonitrile, barrex resin, polyvinyl alcohol, polyvinyl acetate, polymethyl methacrylate, nylon-6, nylon-6,6, Polyurethane, polytetramethylene ether, polyvinylpyrrolidone, poly-4-vinylpyrrolidone,
Particularly preferred are poly-2-vinylpyridine, poly-N-vinylcarbazole, and the like, but the present invention is not limited thereto.

Moreover, it goes without saying that two or more of these may be used as a blend, or a copolymer thereof may be used.

Next, a general method for producing the conductive resin composition of the present invention will be explained. First, carbon is dispersed in a polymer capable of forming a complex adduct with a predetermined amount of iodine. Methods for adding carbon include a method in which the polymer is dissolved in a solvent, carbon is added and mixed therein, and the solvent is then removed, or a method in which carbon is kneaded and dispersed directly into the polymer. Iodine is added to the polymer carbon composite thus obtained. As an iodine addition method,
(1) A method of bringing iodine vapor into contact with the polymer-carbon composite as described above, (2) A method of immersing the polymer-carbon composite in a solution containing iodine, (3) A method of melting and kneading iodine into the polymer-carbon composite. etc. Note that instead of preparing the polymer-carbon composite in advance, a method may also be adopted in which carbon and iodine are added to a predetermined amount of polymer at the same time and kneaded in a dispersed state to produce a conductive resin composition in one step. In this case, there are no particular restrictions on the order of addition or mixing of the substances added for kneading.

That is, in short, it is only necessary to create a composite in which carbon is dispersed in a complex adduct of a polymer and iodine and/or a dispersion composition of iodine, and the manufacturing method is not particularly limited. .

Examples of the carbon added in the present invention include carbon black, acetylene black, graphite, and Kettien black (trademark of AKZO). are preferably used. The amount of carbon used varies depending on the type of carbon, but it is usually 0.5 to 60% of the polymer to be added.
(wt%, the same applies hereinafter), which is 0.5% to 50% for Ketschien black and 0.5% to 40% for crushed graphite. If the iodine content is less than this value, the efficiency of addition is low and the electrical conductivity decreases rapidly when the iodine content is low, and even if it is used in excess of the above value, the effect will not improve any further and the moldability will deteriorate. For example, in Ketsuchen Black, 5~
40% is more preferred, and 10-30% is particularly preferred.

The iodine-containing conductive resin composition of the present invention does not reduce its conductivity even if iodine is released, so when it is used, for example, as a positive electrode mixture for a battery, the electromotive force of the battery will increase even as discharge progresses. can be held constant.

The iodine-containing resin composition of the present invention has excellent electrical conductivity, the electrical conductivity hardly changes depending on the iodine content, and since it is mainly made of plastic, it has excellent processability. Positive electrode mixture, electrolytic capacitor, conductive film,
It can be suitably applied to various fields such as conductive plastic plates.

The present invention is particularly suitable for general-purpose resins that are inexpensive, mass-produced, and have excellent processability. For example, when applied to iodine charge transfer complexes of polymers such as polyacrylonitrile, polyether, polyvinyl alcohol, polyamide, and polyurethane, its practical effects are greatly exhibited.

For example, in order to use the composition as a positive electrode mixture for a battery, it is molded into an appropriate shape and used as the positive electrode, and a metal such as lithium, aluminum, magnesium, zinc, or cadmium is used as the negative electrode and ion conductive material is formed in between. All you have to do is put your body in there and make contact.

When the composition is applied to a wet aqueous battery, a positive electrode made of the composition may be brought into contact with a metal negative electrode via a liquid electrolyte. At this time, in addition to the electrolyte generated by discharge, electrolyte solutions such as ammonium chloride, sodium chloride, zinc chloride, sodium bromide, potassium bromide, lithium iodide, and zinc iodide may be used as auxiliary electrolytes. .

Furthermore, it is convenient to sandwich a porous separator between both active materials to prevent self-discharge.

In addition, if it is applied to a wet non-aqueous battery, for example, if lithium or sodium is used as the negative electrode, propylene carbonate or γ
- It is desirable to use less reactive solvents such as butyllactone. Furthermore, it is convenient to use the metal iodide dissolved in these solvents by impregnating it into a porous material capable of holding a large amount of liquid, such as short glass fiber mat, as a support. A battery can be assembled by sandwiching the porous material impregnated with such an electrolyte between a positive electrode and a negative electrode made of the above-described composition of the present invention.

Furthermore, if it is applied to a solid electrolyte battery, the positive electrode mixture and the negative electrode metal may be brought into contact via a solid electrolyte thin film.

Hereinafter, embodiments of the present invention will be explained in more detail with reference to Examples, but these are merely illustrative, and the technical scope of the present invention as defined in Article 70 of the Patent Law is not limited by these. shall not be construed as being construed.

Example 1 Polyacrylonitrile (average molecular weight 152000) 8
(weight, the same hereinafter) was dissolved in dimethylformamide, and dissolved in dimethylformamide.
2 parts (trademark) was added and well dispersed. Dimethylformamide was removed by evaporation to obtain a black composition. After crushing 10 parts of this composition, 8 parts of each
Place 72 parts of iodine into a 100 ml three-necked flask, seal the flask under reduced pressure, and mix at 140°C with stirring.
An iodine-containing conductive composition A of the present invention was obtained by kneading and dispersing iodine and varying the iodine content.

The electrical conductivity of this composition at room temperature (25°C) is 6
(Scm ^-1 ) is shown in Figure 1.

For comparison, the same measurements were conducted on Composition B, which was prepared in the same manner except that Kettchen black was not added, and the results are shown in FIG.

Example 2 Polyvinyl alcohol (manufactured by Kuraray Co., Ltd.) 7.2 parts (weight, same hereinafter) and polymelamine resin Cymel
303 (trademark of Mitsui Toatsu Co., Ltd.) was dissolved in water, and 2 parts of Ketchen Black KB-EC was added to this aqueous solution and well dispersed. Water was removed by evaporation to obtain a black composition. After crushing this composition, each
Place 72 parts of iodine into a 100 ml three-necked flask, seal it tightly under reduced pressure, and bring it to a molten state at 140°C with stirring.
An iodine-containing conductive composition A of the present invention was obtained by kneading and dispersing iodine and varying the iodine content.

The electrical conductivity of this composition A at room temperature (25°C) is 6
(Scm ^-1 ) is shown in Figure 2. For comparison, the results for Composition B, which was prepared in the same manner except that Ketchen Black was not added, are also shown in FIG.

Example 3 8 parts (weight, same hereinafter) of nylon-6 (manufactured by Toray Industries, Inc.) was dissolved in formic acid to prepare KETSUCHEN BLACK KB.
-Two parts of EC (trademark of AKZO) were added and well dispersed. Formic acid was removed by evaporation to obtain a black composition. After crushing this composition, 72 parts each from 8 parts
of iodine was placed in a 100 ml three-necked flask, sealed under reduced pressure, and brought to a molten state at 115° C. while stirring to obtain an iodine-containing conductive composition A of the present invention in which iodine was dispersed and the iodine content was varied.

The electrical conductivity of this composition A at room temperature (25°C) is 6
(Scm ^-1 ) is shown in Figure 3.

For comparison, the results for Composition B, which was prepared in the same manner except that Ketchen Black was not added, are also shown in FIG.

Example 4 Polymethyl methacrylate (average molecular weight
152000) (weight, same hereinafter) was dissolved in ethyl acetate, and dissolved in ethyl acetate,
2 parts (trademark) was added and well dispersed. Ethyl acetate was removed by evaporation to obtain a black composition.
After pulverizing this composition, 8 parts to 72 parts of iodine were placed in a 100 ml three-necked flask, sealed tightly under reduced pressure, and melted at 115°C with stirring to disperse the iodine and change the iodine content. An iodine-containing conductive composition A was obtained.

The electrical conductivity of this composition A at room temperature (25°C) is 6
(Scm ^-1 ) is shown in Figure 4.

For comparison, the results for Composition B, which was prepared in the same manner except that Ketchen Black was not added, are also shown in FIG.

Example 5 Polyvinylpyrrolidone (average molecular weight 163000) 8
(weight, same hereinafter) dissolved in tetrahydrofuran,
2 parts (trademark) was added and well dispersed. Tetrahydrofuran was removed by evaporation to obtain a black composition. After pulverizing this composition, 8 parts to 72 parts of iodine were placed in 100 ml three-necked flasks, sealed tightly under reduced pressure, and melted at 115°C with stirring to disperse iodine and change the iodine content. An iodine-containing conductive composition A was obtained.

The electrical conductivity of this composition A at room temperature (25°C) is 6
(Scm ^-1 ) is shown in Figure 5.

For comparison, the results for Composition B, which was prepared in the same manner except that Ketchen Black was not added, are also shown in FIG.

Example 6 Poly-2-vinylpyridine (average molecular weight 80000)
Dissolve 8 parts (weight, same below) in tetrahydrofuran and add KETSUCHEN BLACK KB-EC.
(trademark of AKZO) was added and well dispersed.
Tetrahydrofuran was removed by evaporation to obtain a black composition. After pulverizing this composition, 8 parts to 72 parts of iodine were placed in a 100 ml three-necked flask, sealed tightly under reduced pressure, and melted at 115°C with stirring to disperse the iodine and change the iodine content. An iodine-containing conductive composition A was obtained.

The electrical conductivity of this composition at room temperature (25°C) is 6
(Scm ^-1 ) is shown in Figure 6.

For comparison, the results for Composition B, which was prepared in the same manner except that Ketchen Black was not added, are also shown in FIG.

Example 7 Polytetramethylene ether (reduced viscosity 1.12 in 0.1% benzene solution; T.Otsu, eta,
Makromol, Chem., 71 150 (1964)) was dissolved in ethyl cellosolve acetate, and 2 parts of Ketsutien Black KB-EC (trademark of AKZO) were added and well dispersed. Ethyl cellosolve acetate was removed by evaporation to obtain a black composition.
After pulverizing this composition, 8 parts to 72 parts of iodine were placed in a 100 ml three-necked flask, sealed tightly under reduced pressure, and melted at 115°C with stirring to disperse iodine and change the iodine content. An iodine-containing conductive composition A was obtained.

The electrical conductivity of this composition A at room temperature (25°C) is 6
(Scm ^-1 ) is shown in Figure 7. For comparison, FIG. 7 also shows the results for Composition B, which was prepared in the same manner except that Ketchen Black was not added.

Example 8 A polyurethane synthesized from 4.2 parts of tolylene diisocyanate (TDI-80/20) manufactured by Mitsui Nisso Urethane Co., Ltd. and 3.8 parts of tripropylene glycol was dissolved in phenol to obtain Ketsutien Black KB-EC.
(trademark of AKZO) was added and well dispersed.
Phenol was removed by evaporation to obtain a black composition. After crushing this composition, 8 parts each
72 parts of iodine was placed in a 100 ml three-necked flask, the flask was sealed tightly under reduced pressure, and the flask was brought to a molten state at 150° C. while stirring to obtain an iodine-containing conductive composition A of the present invention in which the iodine content was varied by dispersing the iodine. .

The electrical conductivity of this composition A at room temperature (25°C) is 6
(Scm ^-1 ) is shown in Figure 8. For comparison, the results for Composition B, which was prepared in the same manner except that Ketchen Black was not added, are also shown in FIG.

As is clear from the above examples, the iodine-containing conductive resin composition of the present invention has excellent characteristics in that the conductivity hardly changes depending on the iodine content and exhibits high conductivity.

This effect is particularly greatest when the composition has a low iodine content, and can be said to be an extremely desirable characteristic when applied to battery positive electrode mixes and electrolytic capacitors.

However, resin compositions that do not contain carbon have low conductivity even when the iodine content is high, and the conductivity rapidly decreases as the iodine content decreases, making them difficult to use as positive electrode mixtures for batteries or storage batteries or electrolytic capacitors. It turns out that it is very difficult to apply it to

Example 9 Polyacrylonitrile (average molecular weight 152000)
24 g was dissolved in dimethylformamide, 6 g of Ketsien Black KB-EC (trademark of AKZO) was added, and the mixture was well dispersed. Dimethylformamide was removed by evaporation to obtain a black composition. After pulverizing 30 g of this composition, it was placed in a 100 ml three-necked flask with 30 g of iodine, sealed tightly under reduced pressure, and heated to 140°C while stirring.
The resin composition of the present invention was obtained by kneading and dispersing iodine.

600 mg of this composition was applied to a disk-shaped carbon fiber (E-715, manufactured by Kureha Chemical Industry Co., Ltd.) with a diameter of 4.5 cm, and this was used as a positive electrode.

A 0.3 mm thick zinc plate (manufactured by Mitsui Mining & Mining Co., Ltd.) was used as the negative electrode.

The electrolyte is a 1 mol/aqueous solution of NH ₄ C, and two sheets of glass fiber paper are impregnated with 2 ml of this, and a separator, Selemion (manufactured by Asahi Glass Co., Ltd.), is used as a separator between them.
A CMV membrane was sandwiched.

This material was placed between the two electrodes to form a battery.

The experiment was conducted at 25° C. under a nitrogen stream, and the initial short circuit current (Isc) during discharge was measured to be 76 mA/cm ² . Moreover, the open circuit voltage at this time was 1.35V. When this battery was discharged at a constant current of 1mA, it could be discharged for 50 hours until the voltage dropped to 0.9V.

Also, this battery can be changed from 1.35V to 0.9V at 2mA constant current.
A charge/discharge test was conducted by discharging for 15 hours to 15 hours and charging from 0.9V to 1.5V for 15 hours, and it was possible to perform at least 300 cycles.

This shows that this battery can be used not only as a primary battery but also as a secondary battery.

For comparison, a battery was made in exactly the same manner as above using a positive electrode mixture without the addition of Ketsuchen Black KB-EC, and evaluated under the same conditions. The initial short circuit current (Isc) during discharge of this battery was measured.
It was 8mA/ ^cm2 . Also, the open circuit voltage at this time is
It was 1.35V. Furthermore, when I conducted a charge/discharge test, I charged the battery after discharging, but the voltage rose so sharply that I was unable to charge it.

[Brief explanation of the drawing]

1 to 8 are graphs showing the characteristics of the conductive resin composition of the present invention.

Claims (1)

[Claims] 1. An iodine-containing conductive resin composition obtained by dispersing carbon in a complex adduct of iodine and a polymer capable of forming a complex adduct and/or a composition in which iodine is dispersed in the polymer.