JPS5854553A - Battery - Google Patents

Abstract

PURPOSE:To obtain a battery which has a large discharge capacity, a small self-discharge and an excellent stability to oxidation by using a P type conductive acetylene high-polymer which has a fibrous microcrystalline structure, as a positive active material, and using a light metal as a nagative active material. CONSTITUTION:A P tyoe conductive acetylene high-polymer is used as a positive active material and is prepared by doping an acetylene high-polymer having a bulk density of 0.7-1.2g/cm<3> with a dopant such as iodine or bromine. After a positive electrode 5 made of such an active material as above is placed in a concave part provided in the lower part of a case 1, a porous circular Teflon sheet 6 is superposed on the electrode 5, and the electrode 5 and the sheet 6 are fixed by caulking with a Teflon ring 8. Next, a felt 4 is superposed on the electrode 5, and impregnated with electrolyte. After that, a negative lithium electrode 2 is placed over the felt 4, with a diaphragm 3 interposed between teh electrode 2 and the felt 4, and these are caulked with a case 7, thereby constituiting a battery. As the above electrolyte, 1 mol/l LiClO4 solution of distilled dehydrated prpylene carbonate is used. A light metal used as a negative active material may be sodium, aluminum or magnesium in addition to lithium.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a P-type polymer obtained by doping an acetylene polymer having a fibrous microcrystalline (fibril) structure and a bulk density of 07 to 1.2 fi 7 cm3 with a dopant. The present invention relates to a battery characterized in that a conductive acetylene polymer is used as a positive electrode active material and a light metal is used as a negative electrode active material.

Conventionally, many proposals have been made regarding high energy density batteries that use light metals, especially lithium, as negative electrode active materials.For example, halogens such as Br2 and 12, CuF2, AgF2, Ag are used as positive electrode active materials.
F, NiF2. CuCl2 + AgC
/2+NiCl2. C0F3, CrF3. MnF3.
SbF,.

CdF2 * AsF31 HgF2 e Cu
Br, CdC1!2 +PbCl2. NiC1
and metal rhodanides, such as c o c z, etc., Ag
Metal rhodanides such as 5CN, CuSCN and N1(SCN)2, MnO2, Cr2o, etc.

V20s t 5n02 e pbo2@ Tl
O2e B1202 v”Os t”C204+
NiO, Ago + HgO + Cu2O, Cu
O, metal oxides such as Ag2WO4, NiS*
AgB5 e CuB5, Pb,, B2
Metal sulfides such as S3 and MnB4S4, Ti
Layered compounds such as C2°NbSe and ws2, fluorinated graphite, organic compounds such as benzoquinones, dinitrobenzene, and pocI! 2. s, ocz2 and 50
Batteries using oxilampalite such as 2C12 have been proposed. Specifically, for example, batteries are known that use graphite and fluorine intercalation compounds as positive electrode active materials, and lithium metal as negative electrode active materials (U.S. Pat. No. 3,514,337
In addition, lithium batteries (manufactured by Matsushita Electric Co., Ltd.) using fluorinated graphite as a positive electrode active material and lithium batteries (manufactured by Sanyo Electric Co., Ltd.) using manganese dioxide as a positive electrode active material are already commercially available. However, these batteries were not necessarily sufficient due to their battery characteristics.

In addition, halogen (C12, Br2゜I) is added to polyacetylene.
2. IC/, IBr, ICI! 3, etc.), or electron-withdrawing substances (PF5, AsF5, Sb
An ultra-thin solid electrolyte battery has also been proposed in which a cathode active material is chemically doped with F5, BFl, etc., and a lithium cathode is used as a negative electrode (Japanese Patent Laid-Open No. 56-52868).

Furthermore, electrochemically uF; , sbF;, s
bcm.

AsF6 e PF; * , ;' , C'1
04, a method of doping polyacetylene with CF3803 was also developed, and the development of a battery using polyacetylene as an electrode became active 39 (1981), J-C S-Ch
em-Commu・.

1981, 317).

However, the acetylene polymers used in these methods are those produced by a conventionally widely known method (Japanese Patent Publication No. 32581/1983). The bulk density of the acetylene high polymer that can be produced by this method is at most 0.
．． It is porous with a size of 697 cm3, and when this acetylene polymer is doped with a dopant, the amount of doping is at most 6 mol per mol of repeating unit CH of polyacetylene, and if the amount of doping is higher than that, the polyacetylene will undergo oxidative deterioration. There was a drawback that the discharge capacity decreased. That is, when an acetylene polymer obtained by a conventionally widely known method is used as an electrode material, it cannot be said that the discharge capacity is necessarily sufficient.

Some of the present inventors have already proposed a method for producing an acetylene polymer having a bulk density of 0.7/i/l:m or more (Japanese Patent Application Laid-Open No. 129404/1983).

No. 55-128419, No. 55-142030, No. 55-145710, No. 55-145711, No. 5
No. 6-10428, Japanese Patent Application No. 55-34687).

In view of the above points, the inventors of the present invention have conducted various studies to obtain a battery with a large discharge capacity, and as a result, they have discovered the present invention.

That is, the present invention has a fibrous microcrystalline (fibril) structure and a bulk density of 0.7 to 1.211/crn3.
The present invention relates to a battery characterized in that a P-type conductive acetylene polymer obtained by doping an acetylene polymer with a dopant is used as a positive electrode active material, and a light metal is used as a negative electrode active material.

The battery of the present invention can be produced by the method (
Compared to a battery using a porous acetylene polymer with a bulk density of at most 0.6 II/crn3 obtained in Japanese Patent Publication No. 48-32581), it not only has a larger discharge capacity but also has a higher self-discharge rate. It is very useful industrially because it has good oxidation stability against oxygen.

In the present invention, examples of the light metal used as the negative electrode active material include alkali metals such as lithium and sodium, aluminum, and magnesium. These light metals have the fibrous microcrystalline (fibril) structure used in the present invention even when used in sheet form, similar to that of general lithium batteries, and have a bulk density of 0.7.
~1.2 g/crn3 acetylene polymer is disclosed in Japanese Patent Application Laid-Open No. 55-129404, which some of the present inventors have already proposed.
No. 55-128419, No. 55-145710, No. 55-145711, No. 56-10428, and Japanese Patent Application No. 55-34687, but are not necessarily limited to these methods. isn't it.

The method for doping the acetylene polymer with a dopant may be either chemical doping or electrochemical doping.

In the present invention, the dopants to be chemically doped into the acetylene polymer include conventionally known (I) halogens such as iodine, bromine, and bromine iodide, (I) arsenic pentafluoride, antimony pentafluoride, silicon tetra7tride, lean pentachloride, phosphorus pentafluoride, salts Φ□□□□□□ metal halide such as aluminum oxide, aluminum bromide and aluminum heptadide, l sulfuric acid, nitric acid, fluorosulfuric acid, Protonic acids such as trifluoromethane sulfuric acid and chlorosulfuric acid, ■ Triacid sulfur, diacid (tJ[, oxidizing agent such as difluorosulfonyl peroxide % (v)A
g Cl 04 , ■ Tetracyanoethylene, tetracyanoquinodimethane, Floranil, 2.3-dichloro-
Examples include 5,6-disiacbenzoquinone and 2,3-syfurome-5,6-disiacbenzoquinone.

On the other hand, examples of dopants to be electrochemically doped into the acetylene high polymer include PF6 and Al silicon.

SbF;, SbC/1”l BF, -, CI!O
, I3-, Arcζ, cp3so; etc., but are not necessarily limited to these.

There are no particular restrictions on the method of doping the acetylene polymer with a dopant, and known methods [for example, J-C-8e Cnem-Comm, 594 (197
9) *J, Electroanal, Chem, upper ball.

115 (1980)], and the doping may be performed by any method, such as under a constant current, under a constant voltage, or under conditions where the current and voltage vary. The current value, voltage value, doping time, etc. during doping are as follows:
It cannot be unconditionally defined because it varies depending on the bulk density and area of the acetylene polymer used, the type of dopant, the type of electrolyte, the required electrical conductivity of the acetylene polymer, and the like. The amount of dopant doped into the acetylene polymer is 2 to 40 mol, preferably 4 to 30 mol, per mol of repeating unit CH in the acetylene polymer. Even if the amount of dopant doped is less than 2 molti or more than 40 molti, a battery with a sufficiently large discharge capacity cannot be obtained.

The electrical conductivity of the conductive acetylene polymer obtained by doping with a dopant in this way is 10-8 to 104Ω, c
rn, but the electrical conductivity of the conductive acetylene polymer used in the present invention is 10 Ω.
It is preferable to have a resistance of 1.0Ω or more, particularly preferably 1.0Ω·α or more.

The electrolyte used in the battery of the present invention includes, for example, an aprotic organic solvent such as propylene carbonate, ethylene carbonate, r-butyrolactone, dimethyl sulfoxide, acetonitrile, formamide, dimethylpolamide, nitromethane, and LiCl0. , LiAlIC
Known electrolytes generally used in batteries that use lithium as a negative electrode active material can be used, such as a combination with a lithium salt such as /4, LiBF4, LiC/, or a solid electrolyte or molten salt using Li as a conductor. .

Furthermore, if necessary in view of the battery structure, a diaphragm made of polypropylene or the like with porous chambers may be used.

Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these in any way.

In addition, in the examples, battery fabrication was performed under an argon gas atmosphere.

Example 1 [Production of acetylene polymer with high bulk density] Toluene 200Fd purified according to a conventional method as a polymerization solvent was added to 11 glass reactors completely purged with nitrogen gas,
A catalyst solution was prepared by sequentially charging 2.94 mmol of tetrabutoxytitanium and 7.34 mmol of triethylaluminum as a catalyst at room temperature. The catalyst solution was a homogeneous solution. Next, the reactor was cooled with liquid nitrogen, and the nitrogen gas in the system was exhausted using a vacuum pump. The reactor was cooled to −78° C., and purified acetylene gas at a pressure of 1 atmosphere was blown into the reactor while the catalyst solution was left standing. At the beginning of polymerization, the entire system became agar-like. The polymerization reaction was continued for 10 hours while maintaining the pressure of the acetylene gas at 1 atm. The system was agar-like with a reddish-purple color. After the polymerization, unreacted acetylene gas was removed, and the system was washed four times with 200 rnl of purified toluene while keeping the temperature at -78°C to form a swollen acetylene sheet with a toluene-swollen film thickness of about 0.5 crn. A high polymer was obtained. This swollen acetylene polymer was a swollen product in which fibrous microcrystals (fibrils) with a diameter of 300 to 500 A were regularly intertwined, and no powder or lump-like polymer was produced.

This sheet-like swollen acetylene high polymer was sandwiched between chromium-plated ferro plates, pre-pressed at room temperature at a pressure of 1ookp/crn2, and then high-pressure pressed at a pressure of 15tOn/crn2 to produce a uniform, reddish-brown metallic luster. A flexible acetylene polymer film having a thickness of 120 μm was obtained. This film was vacuum dried for 5 hours at room temperature.

The bulk density of the obtained acetylene polymer film was 1.
0517 cc, and the film was found to be non-porous by electron microscopy observation. Further, this acetylene polymer film was a P-type semiconductor with a cis content of 90% and an electrical conductivity at 20° C. (DC four-terminal method) of 4.8×10 Ω·sub.

[Doping experiment of acetylene polymer] A small piece with a width of 0.5 crn and a length of 2°0 crn was cut out from the acetylene polymer with a bulk density of 1.0'59/CC produced by the above method. LiP is mechanically crimped and fixed to a platinum wire to serve as an anode electrode, and a platinum plate is used as the other electrode.
A propylene carbonate solution with a F6 concentration of 0.3 mol/l was used as the electrolyte under constant current (1.0 mA).
Doping was carried out for 10 hours. After doping, the doped acetylene polymer film was washed repeatedly with propylene carbonate to obtain a doped acetylene polymer with a golden metallic luster.The composition of this doped acetylene polymer film was From the analysis [
CH (PF6). 189:EX, and its electrical conductivity (DC four-terminal method) was 2,540Ω·m.

[Battery discharge experiment]' The composition obtained by the above method was (CH(PFa), ta
,'s.

A battery was constructed using a conductive acetylene polymer as a positive electrode active material and lithium as a negative electrode active material.

FIG. 1 is a schematic cross-sectional view of a battery cell for measuring the characteristics of a button-type battery, which is a specific example of the present invention, in which 1 is a brass container plated with Ni, 2 is a disc-shaped lithium negative electrode with a diameter of 20 cm,
3 is a circular porous polypropylene diaphragm with a diameter of 261 al, 4 is a circular felt made of carbon fiber with a diameter of 26 cm, 5 is a positive electrode, and 6 is a Teflon sheet with holes with an average diameter of 2 μm (manufactured by Sumitomo Electric Industries, Ltd., Fluo O゛Qui rFP-2
00), 7 is a Teflon container with a circular cross section, 8 is a Teflon ring for fixing the positive electrode, and 9 is a Ni lead wire.

The positive electrode was placed in the recess at the bottom of the container 1, and a circular porous Teflon sheet 6 was placed over the positive electrode, and then tightened and fixed with a Teflon ring 8.

Place the felt 4 in the recess at the top of the container 1 and overlap it with the positive electrode.
After being impregnated with the electrolyte, the lithium negative electrode 2 is inserted through the diaphragm 3.
was placed and tightened with container 7 to produce a battery. The electrolyte was L dissolved in distilled dehydrated propylene carbonate.
iCl0. A 1 mol/l solution of was used.

The open circuit voltage of the battery thus produced was 3.9V. When a constant current discharge of 0.5 mA was performed in argon, the relationship between discharge time and voltage was shown by the curve (a) in Figure 2.
) became like this.

Comparative Example 1 [Manufacture of acetylene high polymer with low bulk density] A 5.1 m glass reactor with an internal volume of 500 m was placed in a nitrogen atmosphere.
7! (15.0 mmol) of titanium tetrabutoxide was added and dissolved in 20.0 ml of toluene, and then 5.4 mJ (40 mmol) of triethylaluminum was added and reacted with stirring to prepare a catalyst solution.

The reaction vessel was cooled with liquid nitrogen, the nitrogen gas in the system was evacuated with a vacuum pump, and then the reaction vessel was cooled to -78°C.

After rotating the reaction container to uniformly adhere the catalyst solution to the inner wall of the reaction container, immediately add 1
Polymerization was initiated by introducing purified acetylene gas at a pressure of atmospheric pressure. Simultaneously with the initiation of polymerization, an acetylene high polymer with metallic luster was deposited on the inner wall of the reaction vessel. The polymerization reaction was carried out at a temperature of -78°C for 1 hour while maintaining the acetylene pressure at 1 atm, and then the unreacted acetylene was evacuated with a vacuum pump to stop the polymerization. After removing the remaining catalyst solution with a syringe under nitrogen atmosphere, purified toluene 1 was added while keeping it at -78℃.
Washing with 001 was repeated six times, followed by vacuum drying at room temperature.

At the portion where the catalyst solution adhered to the inner wall of the reactor, a film-like acetylene high polymer having an area equal to that portion, a thickness of 90 μm, and a cis content of 98% was obtained.

The electrical conductivity (DC four-terminal method) of this film-like acetylene polymer was 2.5×10 Ω·G at 20°C. The bulk density of this film was 0.5297 cc.

[Doping experiment of acetylene polymer] From the acetylene polymer with a bulk density of 0.52 g/cc manufactured by the above method, a width of 0.5 crn and a length of 2°0 crn was obtained.
A small piece was cut out and mechanically crimped and fixed to a platinum wire to serve as the anode electrode, and a platinum plate was used as the other electrode.
A propylene carbonate solution with a concentration of iPF6 of 0.3 mo/l was used as the electrolyte, and a constant current (1,01
01A) for 5 hours. After the doping was completed, the doped acetylene polymer film was repeatedly washed with propylene carbonate to obtain a doped acetylene polymer having a golden metallic luster. The composition of the doped acetylene polymer film was determined by elemental analysis [CH(PF'6). jQ2:)%, and its electrical conductivity (DC four-terminal method) was 820Ω·α.

[Battery discharge experiment]

A battery was prepared in exactly the same manner as in Example 1, except that the conductive acetylene polymer obtained by doping PFi with the acetylene polymer having a bulk density of 0.521/cc obtained in Example 1 was used as the positive electrode active material. When we conducted a discharge experiment, the relationship between discharge time and voltage was K as shown in Figure 2 (bl).
The open circuit voltage of this battery was 3.7V.

Example 2 [Doping experiment on acetylene polymer] Using the acetylene polymer with a bulk density of 1.05 g/cc obtained in Example 1, LiPF was used as the supporting electrolyte in Example 1.
6 instead of LiCl0. Example 1 except that
A doping experiment was carried out in exactly the same manner as in , and the composition was (
CH(CI!04)o, +oo]x (7) An electrically conductive acetylene polymer having an N gas conductivity (DC four-probe method) of 540 Ω-1·crn-1 was obtained.

[Battery discharge experiment] The composition used as the positive electrode active material in Example 1 was [CH(PF
6). , 8゜
) o, loo ]

Further, the open circuit voltage of this battery was 3.75V.

Comparative Example 2 [Doping experiment of acetylene polymer] The bulk density used in Example 2 was 1.05. The bulk density obtained in Comparative Example 1 was 0.529 instead of the acetylene high polymer with p/σ3.
A doping experiment was carried out in exactly the same manner as in Example 2 except that an acetylene polymer of /Crn3 was used, and the composition was (CH(CJO+)., fill)×,
Obtain an electrically conductive acetylene polymer having an electrical conductivity (DC four terminal method) of 861-1 Ω.

[Battery discharge experiment]

The composition used as the positive electrode material in Example 1 was (CH(PF6
). , tso]x, the composition obtained by the above method instead of the conductive acetylene polymer (cH(czo, )., IQ
A battery discharge experiment was conducted in the same manner as in Example 1 except that the conductive acetylene polymer of IIX was used.
The results shown in figure (d) were obtained. Further, the open circuit voltage of this battery was 370V.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a battery cell for measuring the characteristics of a button-type battery, which is a specific example of the present invention, and FIG. 2 is a diagram showing the relationship between battery discharge time and voltage in an example of the present invention. . 1... Container, 2... Lithium negative electrode, 3...
Diaphragm, 4... Felt, 5... Positive i, 6
...Porous Teflon sheet 7...Teflon container, 8...Teflon ring, 9...Ni lead wire. Patent applicant Showa Denko K.K. agent Patent attorney Sei Kikuchi

Claims (1)

[Claims] A P-type conductive acetylene polymer obtained by doping a dopant into an acetylene polymer having a fibrous microcrystalline (fibril) structure and a bulk density of 0.7 to 1.2 g 7 cm3 is used as a positive electrode active material. A battery characterized by using a light metal as a negative electrode active material.