JPS61183873A - Secondary cell - Google Patents

Abstract

PURPOSE:To obtain high energy density, low self-discharge and high coulomb efficiency by making a positive electrode of a polymer of a fixed pyrrole derivative while making a negative electrode of an acetylene high polymer and a solvent of electrolyte of an ether system compound. CONSTITUTION:A polymer to be used as a positive electrode is obtained by polymerizing a pyrrole derivative to be expressed by the formula as shown. N-methyl-pyrrole and N-tolyl-pyrrole are used as the pyrrole derivative. The kinds of acetylene high polymers to be used as a negative electrode are not especially limited, for instance, the acetylene high polymer or the like to be obtained in a filmy state when being polymerized is used. Further, as an ether system compound to be used for a solvent of an electrolyte the aliphatic family, alicyclic type and aromatic family ether system compounds are used.

Description

[Detailed description of the invention] It is something that

So-called polymer batteries, in which a polymer compound having a conjugated double bond in the main chain is used as an electrode, are expected to be used as high-energy-density secondary batteries.

Many reports have already been made regarding polymer batteries, such as P. J. Nigray et al., J. C. S.
,,Chem,Commun,, 1979.594
:J, E 1ectrochea+, Soc,
JJJ], 1651, JP-A-56-136469@
, No. 57-121168, No. 59-3870, No. 5
No. 9-3872, No. 59-3873, No. 59-196
No. 566, No. 59-196573, No. 59-2033
No. 68, No. 59-203369, etc. can be mentioned as some of them.

However, conventionally known documents disclose polymer batteries in which various positive electrodes, negative electrodes, supporting electrolytes, and organic solvents are combined; No material has been obtained that simultaneously satisfies the following three performances: I) high energy density, (II) low self-discharge, and (I[[) high Coulombic efficiency.

The present inventors have arrived at the present invention as a result of various studies on combinations of electrode materials and electrolyte solvents that simultaneously satisfy the three battery performances described above.

That is, the present invention provides a secondary battery whose main components are an electrode and an electrolyte, in which the negative electrode is made of an acetylene polymer, the positive electrode is a polymer of a pyrrole derivative represented by the general formula below, and the solvent of the electrolyte is an ether-based one. The present invention relates to a secondary battery characterized by being made of a compound.

[However, in the formula, R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. ] The polymer used as the positive electrode of the secondary battery of the present invention is obtained by polymerizing the pyrrole derivative represented by the above general formula.

Methyl-pyrrole, N-ethylpyrrole, N-phenyl-pyrrole, N-tolyl-pyrrole and the like can be mentioned.

The polymer of the pyrrole derivative may optionally be a copolymer of the pyrrole derivative and another compound that can be copolymerized. Examples of compounds copolymerizable with pyrrole derivatives include other pyrrole derivatives such as monoalkyl- or dialkyl-substituted pyrrole and monohalogen- or dihalogen-substituted pyrrole at the carbon atom, cyclopentadiene, azulene, etc. and its derivatives such as benzazulene, kayaazulene, and also fulpene, indene or quadrate acids are also suitable.

Heterocyclic compounds such as imidazoles, thiazoles, furans or thiophenes may also be used. Additionally, 2-bromothiophene, 2,6-dimethylpyridine and pyrazine can be used. For 1 mole of pyrrole derivative, the copolymer is
A compound copolymerizable with a pyrrole derivative may be contained in an amount of 0.1 mol or more and less than 1 mol.

The polymer of pyrrole derivative used in the present invention is preferably obtained by electrochemical polymerization of the pyrrole derivative, in which case the polymerization of the upper layer is carried out by anodic oxidation. For this purpose, a current density of 2 to 20 mA/cM2 is used, for example. In most cases, a voltage of 10 to 300 volts is applied. The polymerization is preferably carried out in the presence of an auxiliary liquid in which the pyrrole derivative is soluble. For this purpose, polar organic solvents can be used. When using a water-miscible solvent, a small amount of water may be added. Suitable solvents are alcohols, ethers such as dioxane or tetrahydrofuran, acetone or acetonitrile, dimethylformamide or N-methylpyrrolidone.

Polymerization of 7mer is carried out in the presence of a complexing agent. This is BFi, As Fi as an anion.

ASFi, SbFi, SbC official, PFi.

It means a salt containing the groups cioi, H8Oi and SO42-.

These salts contain, for example, quaternary ammonium cations, lithium, sodium or potassium as cations. The use of compounds of this type is known and is not the subject of the present invention. These compounds are usually used in rivers where the polymer of pyrrole derivative contains 20 to 40 mole % of the anionic complexing agent.

However, other known methods are also available for producing polymers of pyrrole derivatives. For example, pyrrole derivatives can be polymerized in aqueous solution with strong acids or with inorganic peroxides, such as potassium persulfate. According to the last mentioned method, a polymer of pyrrole derivative is obtained in the form of a fine powder. Since salt is present in these methods as well, the polymer of pyrrole derivative is a complex compound with the corresponding anion.

The molded pyrrole derivative polymer used as the electrode of the battery of the present invention can be obtained by various methods. For example, in the case of anodizing polymers of pyrrole derivatives, a polymer is formed which is complexed with anions and assumes the form of the anode used.

If the anode has a flat shape, a flat layer of polymer will be formed. When using a method for producing a fine polymer powder of a pyrrole derivative, this fine powder can be compression molded into a molded body by a known method under pressure and heat. often 150
Temperatures of ˜300° C. and pressures of 50 to 150 bar are used. According to this known method for producing polymers of anionic complexed pyrrole derivatives, shaped bodies of any desired shape can be obtained. Thus, for example, thin films, plates or three-dimensional moldings are used.

The type of acetylene polymer used as the negative electrode of the secondary battery of the present invention is not particularly limited. For example, (1) an acetylene polymer obtained in the form of a film during polymerization (Japanese Patent Publication No.
581), (2) Acetylene polymer molded products obtained by pressure molding an acetylene polymer swollen with a gel or organic solvent (JP-A-55-128419, JP-A-55-128419, JP-A No. 56)
-10428, No. 56-133133), (3)
(4) Acetylene polymer molded product obtained by pressure molding short fibrous acetylene polymer powder having a fibrous microcrystalline (fibril) structure; (4) Pressure molding of spherical acetylene polymer powder Acetylene high polymers such as acetylene high polymer molded products obtained by

Among these acetylene high polymers, for the purpose of maximizing the effects of the present invention, the above (2) or (3) is preferred.
Particularly preferred are those.

The pyrrole derivative polymer and the acetylene polymer used in the electrode of the secondary battery of the present invention may also contain other suitable conductive materials, such as graphite, carbon black, acetylene black, etc., as is well known to those skilled in the art. , metal powder, carbon fiber, metal fiber, etc. may be mixed. Also,
Polyethylene, modified polyethylene, polypropylene, poly(detrafluoroethylene), ethylene-propylene-dieneter polymer (EPDM), sulfonated EP
It may be reinforced with thermoplastic resin such as DM.

Further, in the present invention, there is no problem in doping at least one of the pyrrole derivative polymer and the acetylene high polymer in advance. Doping can be carried out both chemically and electrochemically.

As the ether compounds used as the solvent of the electrolyte of the secondary battery of the present invention, aliphatic, alicyclic and aromatic ether compounds are used. Among these, alicyclic and aromatic ether compounds are used. type compounds are preferred, and alicyclic ether type compounds are particularly preferred.

Specific examples of ether compounds include tetrahydrofuran, 2-methyl-tetrahydrofuran, 2,5-dimethyl-tetrahydrofuran, 3-methyl-tetrahydrofuran, 3,4-dimethyl-tetrahydrofuran, biran, dioxolane, dimethyl ether, dioxane, 1,
2-dimethoxyethane, dimethoxyethane, diglyme, 1,3-dioxolane, anisole, etc. can be used. These solvents can be used alone or as a mixture of two or more. In addition, organic solvents other than ether compounds that are inactive during battery operation, such as tetraethylsulfonamide, methyl formate, dimethyl sulfoxide, 3-methyl-2-oxazolidinone, 1-
Methyl-2-pyrrolidinone, dimethylformamide, 3
-Methyl-2-oxazolidinone, 1-methyl-2-pyrrolidinone, dimethylformamide, hequinamedylphosphorylamide, sulfolane, 3-methyl-sulfolane,
A mixed solvent of γ-butyrolactone or the like and the above-mentioned ether compounds can also be used.

Typical cationic components of the supporting electrolyte used in the electrolytic solution of the secondary battery of the present invention include, for example, metal cations of metals whose Pauling electronegativity value does not exceed 1.6 or whose general formula is R4-xMHx+ or R3E” (however, R
is an alkyl group or aryl group having 1 to 10 carbon atoms, M
is N, P or AS, E is O or 3. (x is an integer from O to 4), and typical anion components of the supporting electrolyte include, for example, t
Bacuoi, PFi, As Fi, As Fi
.

SO3CFi, BF''4, and BRi (wherein, R is an alkyl group or aryl group having a carbon bed number of 1 to 10). Specific examples of supporting electrolytes include Li PFa,
, LiSbFa, LiClO4.

Li As Fa, CF3803 Li, Li B
F4.

LiB(Bu)4. LiB(Et)2 (Btl)2゜j'Ja PFa, Na BF4, NaΔS Fa
.

Na B (3u) 4, KB (BIJ) 4
, KAS Fa, etc., but are not necessarily limited to these. These supporting electrolytes may be used alone or in combination of two or more.

The concentration of the supporting electrolyte cannot be unconditionally defined because it varies depending on the type of pyrrole derivative polymer or acetylene polymer used, charging conditions, operating temperature, type of supporting electrolyte, type of solvent, etc., but in general is 0
．． It is preferably within the range of 5 to 10 mol/1. The electrolyte may be homogeneous or heterogeneous.

1. The secondary battery of the present invention has the features of (I>small self-discharge and (n) good cycle life compared to conventionally known polymer batteries, and furthermore, Compared to secondary batteries currently on the market (lead-acid batteries, I'Ji-cd batteries), it has the advantage of having a higher energy density, and can be used in various portable electrical devices.
Extremely useful as a power source for computers and electric vehicles.

Shio 1 Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 [Manufacture of negative electrode] In a 1-hour glass reaction vessel that was completely replaced with nitrogen gas,
A 100-mesh stainless steel mesh was inserted, and then 10% of toluene purified according to a conventional method was used as a polymerization solvent.
0Id, tetrabutoxytitanium as catalyst 4.41
A catalyst solution was prepared by sequentially charging mmol and 11.01 mmol of triethylaluminum at room temperature. The catalyst solution was a homogeneous solution. Next, the reaction vessel 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. 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 d of purified toluene while keeping the system temperature at -78°C to form a stainless steel film with a toluene-swollen film thickness of about 0.5 CM. A sheet-like swollen acetylene polymer containing a network of This 8-water acetylene high monomer polymer was a swollen product in which fibrous microcrystals (fibrils) having a diameter of 300 to 500 people were regularly intertwined, and no powder or lump-like polymer was produced.

This sheet-like swollen acetylene polymer containing the stainless steel mesh is sandwiched between chrome-plated ferro plates.
Preliminary pressing was carried out at a pressure of 100 kg/υ2 at room temperature, and then pressing was carried out at a pressure of 15 ton 7 cm2 to obtain a uniform and flexible composite having a reddish-brown gloss and a film thickness of 280 μm. This composite was vacuum dried at V temperature for 5 hours.

This composite contained 43% by weight stainless steel mesh.

[Manufacture of positive electrode] In a glass container, add 120 d of acetonitrile, N-methyl-
Pyrrole 0.52 fJ and lithium perchlorate 0.2
0 g was charged. 1 each at intervals of 4 ctn in solution.
After inserting two platinum electrodes of 4α2, electrolysis was carried out at 1140 ampere-seconds while stirring. At this time, a black N-methyl-pyrrole polymer film was deposited on the anode. Clean the coated anode with acetonitrile and heat at 60°C.
After drying, the resulting polymer film of N-methyl-pyrrole was peeled off from the platinum.

[Battery Experiment] Disks with a diameter of 20JI11 were cut out from the stainless steel-reinforced acetylene polymer and N-methyl-pyrrole polymer films obtained by the above method, and used as negative and positive electrodes to form a battery. Configured.

The figure is a schematic cross-sectional view of a battery cell for measuring the characteristics of a secondary battery, which is an integral example of the present invention, and 1 is a platinum lead wire for the negative electrode;
2 is a platinum wire mesh current collector for negative electrode with a diameter of 20#l111,80 mesh, 3 is a disc-shaped negative electrode with a diameter of 20 m, and 4 is a diameter of 20 m.
5 is a circular porous polypropylene diaphragm with a thickness that can be sufficiently impregnated with electrolyte, 5 is a disk-shaped positive electrode with a diameter of 20 #I, 6 is a platinum wire mesh current collector for the positive electrode with a diameter of 20 m and 80 meshes, 7 is a positive electrode lead wire, and 8 is a screw-type Teflon container.

First, the platinum wire mesh current collector 6 for the positive electrode is placed in a Teflon container 8.
Further, the positive electrode 5 is placed on the platinum wire mesh current collector 6 for the positive electrode, the porous polypropylene diaphragm 4 is placed on top of it, and after sufficiently impregnated with the electrolyte, the negative electrode 3 is placed on top of the positive electrode 5.
Further, a platinum wire mesh current collector 2 for a negative electrode was placed on top of the current collector 2, and a Teflon container 8 was tightened to produce a battery.

As the electrolytic solution, a 1 mol/1 solution of L; BF4 dissolved in 2-methyl-tetrahydrofuran which had been distilled and dehydrated according to a conventional method was used.

Using the battery prepared in this way, an electric chamber was run under a constant current (0.4 mA/IJ2) in an argon atmosphere with doping levels corresponding to 20 mol% and 6 mol% for the positive and negative electrodes, respectively. I charged it. After charging is finished,
Immediately, the battery was discharged under a constant current (1, OmA/α2), and when the battery voltage reached 0.2V, the battery was charged again under the same conditions as in the library. ! The number of repetitions of charging and discharging was recorded as 288 times until the i-electric efficiency decreased to 50%. The highest value of Coulombic efficiency was 100%.

The theoretical energy density of this battery is 123W・hr/K
It was ff. Furthermore, when the battery was left charged for 24 hours, its self-discharge rate was 2.0%.

Comparative Example 1 A battery was produced in exactly the same manner as in Example 1, except that an acetylene polymer was used instead of the N-medylene pyrrole polymer used in the positive electrode in Example 1, and a battery was prepared in the same manner as in Example 1. A battery experiment was conducted. As a result, the number of charge/discharge cycles is 29 times, and the theoretical energy density is 119W.
-hr//(y, self-discharge rate was 37.0%.

Comparative Example 2 N was used instead of the acetylene polymer used in the negative electrode in Example 1.
- Example 1 except that a polymer of methyl-pyrrole was used
A battery was prepared in exactly the same manner as in Example 1, and a battery experiment was conducted in exactly the same manner as in Example 1, but repeated charging and discharging was not possible.

Example 2 A test was carried out except that N-phenyl-pyrrole was used in place of the N-methyl-pyrrole used in Example 1. As a result, the number of charging/discharging cycles was 251 times, and the theoretical energy density was 120 W-hr/N.
g, and the self-discharge rate was 1.8%.

[Brief explanation of drawings]

The figure is a schematic cross-sectional view of a battery cell for measuring characteristics of a secondary battery, which is a specific example of the present invention. 1... Platinum lead wire for negative electrode 2... Platinum wire mesh current collector for negative electrode 3... Negative electrode 4.
・・Porous boli-O-pyrene diaphragm 5 ・Porous electrode 6 ・Platinum wire mesh current collector for positive electrode 7 ・Porous electrode lead wire ・Teflon container

Claims (1)

[Claims] In a secondary battery whose main components are an electrode and an electrolyte,
A secondary battery characterized in that the negative electrode is made of an acetylene polymer, the positive electrode is made of a pyrrole derivative polymer represented by the following general formula, and the solvent of the electrolytic solution is made of an ether compound. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, in the formula, R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. ]