JPS61279059A - Nonaqueous secondary battery - Google Patents

Abstract

PURPOSE:To concurrently meet high energy density, low self discharge, high charge-discharge efficiency, and long cycle life by using an oxidation copolymer of aniline compound containing a specified heterocyclic compound and heterocyclic compound in a positive electrode. CONSTITUTION:In a nonaqueous secondary battery mainly comprising a positive electrode, a negative electrode, and a nonaqueous electrolyte, an oxidation copolymer of aniline family compound containing 1-50mol% of at least one compound selected from heterocyclic compounds indicated in the formulas (a)-(e) and heterocyclic compound is used as the positive electrode. The content of thiophene compound, pyrrole compound, furan compound, or these mixture in the oxidation copolymer is 1-50mol%, preferably 1-30mol%. When the content is less than 1mol%, the effect of copolymer is not obtained and the battery performance is not improved. When the content exceeds 50mol%, the doping rate is decreased and the battery performance is also decreased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has high energy density, low self-discharge,
The present invention relates to a non-aqueous secondary battery that has a long cycle life and good charge/discharge efficiency (Coulombic efficiency).

[Prior Art] 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, for example, B.J.
Nigley et al., Journal of the Chemical Society, Chemical Communication, f:t55
94 pages (1979) (P, J, former gr'ey et al., J
, C, S, , CheIIl, Commun, ,
1979゜594): Journal Electrochemical Society, page 1651 (1981)
(J, Electrochem.

Sac,, t98t, t651), JP-A-1983
-136469, 57-121168, 59-
No. 3870, No. 59-3872, No. 59-3873, No. 59-196566, No. 59-196573,
No. 59-203368, No. 51203369, etc. can be mentioned as some of them.

Additionally, there have already been proposals to use polyaniline, which is obtained by oxidative polymerization of aniline, which is a type of conjugated polymer, as an electrode for aqueous or non-aqueous batteries.
Polymer prebriefings such as A.G. Manc Diarmid. Volume 25, number 2. Page 248 (198
4th year) [A, G, HacDiarmid et al., Pol
ymer Preprints, 25. No, 2.
248 (1984)], Sasaki et al., Electrochemical Society Vol.
0th Conference Abstracts, 123 (1983), Electrochemical Society 51st Conference Abstracts, 228 (1984)).

[Problems to be Solved by the Invention] However, polymer batteries using conventionally known polymers as electrodes have problems such as (i) high energy density, (ii) low self-discharge, (iii) high discharge efficiency, and (1v) It has not been possible to obtain a product that satisfies long cycle life at the same time.

[Means for Solving the Problems] As a result of various studies on electrode materials that simultaneously satisfy the above-mentioned four battery performances, the inventors found that aniline compounds containing polycyclic compounds and complex The inventors have discovered that by using an oxidized copolymer with a cyclic compound as a positive electrode, a nonaqueous secondary battery that satisfies the four battery performances described above can be obtained, and the present invention has been achieved.

That is, the present invention provides a non-aqueous secondary battery having a positive electrode, a negative electrode, and a non-aqueous electrolyte as main components, in which a heterocyclic battery represented by the following general formulas (a), (b), and (c) is used as a positive electrode. At least one compound selected from compounds 1 to 5
The present invention relates to a non-aqueous secondary battery characterized in that it uses an oxidized copolymer of an aniline compound containing 0 mol % of the heterocyclic compound.

[In the formula, 1 or r, Rn and RILL have 1 to 1 carbon atoms
0 alkyl group, X, Y and Z are 0.1 or 2) The aniline compound used in the present invention has the general formula n is 0, 1 or 2; ] Typical examples are aniline, 2
-Methyl-aniline, 3-methyl-aniline, 2,3-
Dimethyl-aniline, 2,5-dimethyl-aniline, 3
．． 5-dimethyl-aniline, 2-methoxy-aniline,
Examples include 3-methoxy-aniline, 2,3-dimethoxy-aniline, 2,5-dimethoxy-aniline, 2-ethoxy-aniline, 2-ethyl-aniline, 2,5-diethoxyaniline and the like. Among these aniline compounds, aniline is preferred.

In the present invention, the heterocyclic compound used as a copolymerization component of the aniline compound is a thiophene compound represented by the general formula <a>, a virol compound represented by the general formula (b), and a virol compound represented by the general formula (c). ) is a furan compound represented by

Examples of thiophene compounds represented by general formula (a) include thiophene, 2-methyl-thiophene, 3-
Among these thiophene compounds, thiophene is preferred.

Specific examples of the virol compound represented by the general formula (b) include virol, 2-methyl-virol, 3-methyl-virol, and the like. Among these virol compounds, virol is preferred.

Specific examples of the furan compound represented by the general formula (c) include furan, 2-methyl-furan, and 3-methyl-furan, and among these furan compounds, furan is preferred.

A thiophene compound represented by the general formula (a), a virol compound represented by the general formula (b) and a general formula (c
) may be used in combination.

The content of thiophene compounds, virol compounds, furan compounds, or mixtures thereof in the oxidized copolymer is
The amount is 1 to 50% by mole, preferably 1 to 30% by mole. If the content of the thiophene compound, virol compound, furan compound, or a mixture thereof in the oxidized copolymer is less than 1 mol%, no copolymerization effect can be obtained;
No improvement effect on battery performance was observed. On the other hand, if the content of the thiophene compound, virol compound, furan compound, or a compound thereof in the oxidized copolymer is more than 50 mol%, a sufficiently high doping rate cannot be obtained;
It is difficult to obtain batteries with good performance.

The oxidized copolymer used in the positive electrode of the secondary battery of the present invention is
It can be produced by either electrochemical polymerization or chemical polymerization.

When an electrochemical polymerization method is used, the polymerization of the seven polymers is carried out by anodic oxidation. For that purpose, for example, 2~20m△
A current density of /12 is used. 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 aniline compound, thiophene compound, virol compound, or furan compound is soluble. Water or polar organic solvents can be used for this purpose. When using a water-miscible solvent, a small amount of water may be added.

Suitable organic solvents are, but are not necessarily limited to, alcohols, ethers such as dioxane or detrahydrofuran, acetone or acetonitrile, benzonitrile, dimethylformamide or N-methylpyrrolidone.

Polymerization is carried out in the presence of a complexing agent. This includes anions such as BF, As Fi, and ASFi;

5bFi, 5bCj-, PFi, C10i.

It means a salt containing the groups ISO';i and 5042-.

These salts contain cations such as H+, quaternary ammonium cations, lithium, sodium or potassium. The use of compounds of this type is known and is not the subject of the present invention. These compounds usually contain an oxidized copolymer containing an anionic complexing agent of 20 to 100T.
It is used in small amounts containing 1%.

If the oxidized copolymers are prepared by chemical methods, for example, mixtures of aniline compounds and thiophene, virol or furan compounds can be prepared in aqueous solution with strong acids or with free peroxides such as potassium persulfate. It can be polymerized by According to this method, the oxidized copolymer is obtained in the form of a fine powder. Since salt is present in these methods as well, the oxidized copolymer becomes a complex compound with the corresponding anion.

Molded bodies that can be used as electrodes can be obtained by various methods. For example, in the case of electrochemical oxidative copolymerization method, usually
The oxidized copolymer is complexed with anion, and what type of anode is used? A copolymer is formed. If the anode has a flat shape, a flat layer of copolymer is formed. When using a method for producing a fine oxidized copolymer powder, this fine powder can be compression molded into a molded body under pressure and heat by known methods. Temperatures from room temperature to 300°C and pressures from 50 to 150 bar are often used.

According to this known method for producing an oxidized copolymer formed into an anionic complex, a molded article of any shape can be obtained. That is, for example, a thin film, a plate or a three-dimensional shaped molding is used.

The oxidized copolymer that is complexed with anions and tq is
It may be used as it is as the positive electrode of the secondary battery of the present invention, or it may be used as the positive electrode after the complexed anions have been chemically or electrochemically removed.

The negative electrode used in the non-aqueous secondary battery of the present invention is not particularly limited, and includes, for example, polypyrrole and polypyrrole derivatives, polythiophene and polythiophene derivatives, conductive polymers such as polyquinoline, boriacene, polyparaphenylene, ren, polyacetylene, graphite, Ti 82, etc. intercalation compounds, alkali metals such as lithium, sodium, lithium-aluminum, and alloys thereof, among which preferred are polyacetylene, polyvaraphenylene, and lithium-aluminum alloys.

The oxidized copolymer and conductive polymer used as the electrode of the secondary battery of the present invention may include other suitable conductive materials, such as carbon black,
Acetylene black, metal powder, metal fiber, carbon fiber, etc. may be mixed.

Further, it may be reinforced with a thermoplastic resin such as polyethylene, modified polyethylene, polypropylene, poly(tetrafluoroethylene), ethylene-propylene dieneter polymer (EPDM), or sulfonated EPDM.

Examples of organic solvents that can be used alone or in combination as a solvent for the electrolyte of the non-aqueous secondary battery of the present invention include the following.

Two examples of alkylene nitrile, crotonitrile (liquid range, -51.1°C to 120°C), two examples of trialkyl borate, trimethyl borate, (cH30) 3B (1-state t
-29,3°C to 67°C) Tetraalkyl silicate: e.g., tetramethyl silicate, (cH30)4 St
(boiling point, 121°C) nitroalkane, nitromethane, Cl-1NO2 (liquid range, -17°C to 100.8°C
) Alkyl nitrile: e.g., acetonitrile, Cl-13
ON (Liquid range, -45°C to 81.6°C) Dialkylamide: e.g., dimethylformamide, IC0N
(cH3)2 (liquid range, -60,48℃~149℃) (liquid range,
-16℃～202℃) Two monocarboxylic acid esters, ethyl acetate (liquid range,
-83.6~77.06℃) 9 18721 cases 1.9.
A/lz t /lz l-□1. ~To, HC (OCH
3) 3 (boiling point, 103°C) (liquid range, -42~
206℃) Dialkyl carbonate example, Dimethyl carbonate, ○C(OCH3)2 (Liquid range, 2~90℃) (Liquid range, -48~242℃) Monoether: Example, Diethyl needle (Liquid range, - 116-34.5°C) Polyethers: Examples, 1,1- and 1,2-dimethoxyethane (liquid range, -113, 2-64.5°C, respectively)
and -58-83°C) cyclic ethers: e.g., tetrahydrofuran (liquid range, -
65-67°C): 1,3-dioxolane (liquid range, -
95-78℃) Two nitroaromatics, nitrobenzene (liquid range, 5.7-210.8℃) Aromatic carboxylic acid halides: e.g., benzoyl chloride (
Liquid range, 0 to 197°C>, benzoyl bromide (liquid range, -24 to 218°C) Aromatic sulfonic acid halide, benzenesulfonyl chloride (liquid range, 14.5 to 251°C) Aromatic phosphonic acid dihydride Halides: Examples, benzenephosphonyl dichloride (boiling point, 258°C), two aromatic thiophosphonic acid dihalides, benzene thiophosphonyl dichloride (boiling point, 124°C at 5M) (melting point, 22°C) 3-methylsulfolane (melting point, - 1°C) Alkyl sulfonic acid halides: e.g., methane sulfonyl chloride (boiling point, 161°C) Alkyl carboxylic acid halides: e.g., acetyl chloride (liquid range, -112 to 50,9°C), acetyl bromide (
Liquid range, -9f3 to 76°C), propionyl chloride (liquid range, -94 to 80°C), two saturated polycyclic compounds, tetrahydrothiophene (liquid range, -96 to 121°C): 3-methyl-2- Oxazolidone (!!! point, 15.9°C) dialkyl sulfamic acid halide: e.g., dimethyl sulfamyl chloride (boiling point, 80°C at 10 mm) alkyl halosulfonate: e.g., ethyl chlorosulfonate (FM point, 151°C) unsaturated hetero Ring carboxylic acid halides: e.g., 2-furoyl chloride (liquid range, -2 to 173°C) Five-membered unsaturated heterocyclic compounds: e.g., 1-methylbicol (boiling point, 114°C)
), 2,4-dimethyldeazole (boiling point, 144°C),
Furan (liquid range, -85,65-3136°C), Nisder and/or halides of dibasic carboxylic acids: e.g., ethyl oxalyl chloride (boiling point, 135°C) Mixed alkylsulfonic acid halides/carboxylic acid halides: Example, chlorosulfonylacetyl chloride (boiling point, 98°C at 10M) dialkyl sulfoxide:
Example, dimethyl sulfoxide (liquid range, 18.4-1
89°C) 2 dialkyl sulfates, dimethyl nalphate (liquid range, -31.75~188.5°C) 2 dialkyl nalphites, 1 to dimethyl sulfite
(Boiling point, 126℃) Two alkylene sulfites, ethylene glycol
Sulfide (liquid range, -11 to 173°C) Halogenated alkanes: e.g., methylene chloride (liquid range, -
95-40°C), 1,3-dichloropropanino (liquid range, -995-120.4°C) Among the above, preferred organic solvents are sulfolane, crotonitrile, nitrobenzene, tetrahydrofuran, methyl-substituted tetrahydrofuran, 1,3- Di-quaternary-solane, 3-methyl-2-oxazolidone, propylene or ethylene carbonate, sulborane, γ-butyrolacone, ethylene glycol nalphi-1, dimethyl sulfite, dimethyl
sulfoxide, and 1,1- and 1,2-dimethoxyethane. This is because they are believed to be the most chemically inert towards battery components and have a wide liquid range, especially since they allow for high and efficient use of cathode materials. It is.

Typical cavon components of the supporting electrolyte used in the electrolyte of the nonaqueous secondary battery of the present invention include, for example, a metal cation of a metal whose Pauling electronegativity value does not exceed 1.6 or a general formula of RMH+ or R3E" (wherein, R is an alkyl group or aryl group having 1 to 10 carbon atoms, M is N,
P or AS atom, E is ○ or S atom, × is O to 4
Typical anion components of the supporting electrolyte include, for example, CJJO'';+, PFi.

As Fii, As Fi, SO3CF'i,
BF'4. and BR″4 (however, R has 1 carbon number
~10 alkyl groups or aryl groups), and the like.

A specific example of the supporting electrolyte is LiPFa.

Li Sb Fa, Li CJ 04, Li
AsFa.

CF35○3 Li, Li 13F4, 1i B
(Bu)4.

Li B (ET)2 (Bu)2. Na PFs
.

NaBF4, NaΔSFo, NaB(Bu)4°KB(Bu)4. Examples include, but are not limited to, KAsFa and the like. These supporting electrolytes may be used alone or in combination of two or more.

The i11 degree of the supporting electrolyte cannot be unconditionally defined as it varies depending on the type of oxidized copolymer used in the positive electrode, the type of cathode, charging conditions, operating temperature, type of supporting electrolyte, type of organic solvent, etc. Generally, it is preferable that the amount is within the range of 0.5 to 10 mol/cross. The electrolyte may be homogeneous or heterogeneous.

In the non-aqueous secondary battery of the present invention, the amount of dopant doped into the oxidized copolymer is 10 to 100 mol%, preferably 10 to 75 mol%, per mol of the repeating unit of the oxidized copolymer. %.

The dope level can be freely controlled by measuring the amount of electricity flowing during electrolysis. The doping can be carried out either under constant current, constant voltage or under varying conditions of current and voltage.

In the present invention, if necessary, a porous membrane made of synthetic resin such as polyethylene or polypropylene or natural fiber paper may be used as the diaphragm.

In addition, some of the electrodes used in the secondary battery of the present invention may react with oxygen or water and deteriorate the performance of the battery, so the battery should be sealed and substantially oxygen-free and water-free. It is desirable that the condition is as follows.

[Effects of the Invention] The non-aqueous secondary battery of the present invention has high energy density, high charge/discharge efficiency, long cycle life, low self-discharge rate, and flatness of voltage during discharge. In good condition. Also,
The secondary battery of the present invention is made of pumice, is small in size, and has a high energy density, so it is suitable for use in portable devices, electric vehicles, gasoline vehicles, and power storage batteries.

[Examples] Hereinafter, the present invention will be explained in more detail by giving Examples and Comparative Examples.

Example 1 [Production method of oxidized copolymer] Distilled water, 1-IBF4, aniline and thiophene were added to a glass container, and the concentrations of HBF4 were 1.5 mol, and the concentrations of aniline and thiophene were 0.7 mol and 0, respectively. The amount was adjusted to .1 mol. 2 c in aqueous solution
Two platinums of 6α2 each with a spacing of m? After charging Tfi, electrolysis was carried out with an electric charge of 120 ampere-seconds while stirring.

At this time, a black-purple oxidized copolymer was deposited on the anode plate.

The coated anode was repeatedly washed three times with distilled water, and then after vacuum drying at 10° C., the resulting oxidized copolymer film was peeled off from the platinum plate. (R-spectrum analysis showed that the obtained oxidized copolymer contained 4.7 mol% thiophene.

Add 1.7d of titanium tetrabutoxide to the container,
A catalyst solution was prepared by dissolving 30 d of anisole and then adding 2.7 d of triethylaluminum with stirring.

This reaction vessel was cooled with liquid nitrogen, and the nitrogen gas in the system was exhausted using a vacuum pump. Next, this reaction vessel was
After cooling to 0.degree. C. and keeping the catalyst solution stationary, purified acetylene gas at a pressure of 1 atmosphere was bubbled through.

Immediately, polymerization occurred on the surface of the catalyst solution, producing a film-like acetylene high polymer. Thirty minutes after the introduction of acetylene, the acetylene gas in the reaction vessel system was exhausted to stop the polymerization.

After removing the catalyst solution with a syringe under nitrogen atmosphere, -78
It was washed repeatedly with 100 ml of purified toluene five times while maintaining the temperature at °C. , 1 - The film-like acetylene polymer swollen with luene was a uniform film-like swollen product in which fibrils were tightly intertwined. Next, this swollen product was vacuum-dried to a reddish-purple color with a metallic luster, a thickness of 180 μm, and a cis-wrinkle content of 98 μm.
% film-like acetylene polymer was obtained. In addition, the bulk density of this film-like acetylene polymer is 0.309/CC, and its electrical conductivity (DC four-probe method) is 3.2× at 20°C.
10 −9 Ω−1·cm”.

[Battery Experiment] Disks with a diameter of 20 m were cut out from the aniline and thiophene L oxidized copolymer film and the membranous acetylene polymer prepared in the above method, and used as active materials for the positive and negative electrodes, respectively, to form a battery. Configured.

The figure is a schematic cross-sectional view of a battery cell for measuring characteristics of a non-aqueous secondary battery, which is a specific example of the present invention, in which 1 is a platinum lead wire for the negative electrode, 2 is a diameter of 20 mm. ．． 8α mesh platinum wire mesh current collector for the negative electrode, 3 is a disc-shaped negative electrode with a diameter of 201 m, 4 is a circular porous polypropylene diaphragm with a diameter of 20#, and is thick enough to be sufficiently impregnated with the electrolyte, 5 is a A disk-shaped positive electrode with a diameter of 20WIR, 6 is a diameter of 20. ．． 80 mesh platinum wire mesh current collector for the positive electrode, 7 a positive electrode lead wire, and 8 a screw-in Teflon container.

First, the platinum wire mesh current collector 6 for the positive electrode is placed in a Teflon container 8.
The positive electrode 5 is placed on the positive electrode platinum wire mesh current collector 6, and the porous polypropylene ceramic 1 is placed on top of the positive electrode platinum wire mesh current collector 6.
f! After putting J4 on the market and sufficiently impregnating it with the electrolyte solution, the negative electrode 3 is stacked, and the platinum wire mesh current collector 2 for the negative electrode is placed on top of it,
A battery was produced by tightening the Teflon container 8.

As the electrolytic solution, a 1 mol/ml solution of 1ipFe dissolved in tetrahydrofuran which had been distilled and dehydrated according to a conventional method was used.

Using the battery prepared in this way, the battery was operated under a constant current (1,7771 A/eta 2) in an argon atmosphere.
The battery was charged by passing current in an amount corresponding to a doping amount of 50 mol % and 6 mol % to the positive electrode and negative electrode, respectively.

Immediately after charging is completed, turn the battery under a constant current (1,571'LA/C).
When the battery was discharged and the battery voltage reached 0.20 V, a repeated charging/discharging test was performed in which the battery was charged again under the same conditions as above, and the charging/discharging efficiency was 6.
The number of times charging and discharging is repeated until it drops to 0% is 53
0 times were recorded.

The energy density at the fifth repetition is 124W.
-hr/K9, the maximum discharge efficiency was ioo%. Also, when I left it charged for 62 hours,
Its self-discharge rate was 2.3%.

Example 2 In Example 1, instead of the acetylene high polymer used for the negative electrode, the acetylene polymer used in Bulletin of the Chemical Society of Japan, Vol. 51, p. 2091 (1978
Year > (Bull, Chem, Soc,
Japan.

51, 2091 (1978)) at 1 ton/cm.
[Battery experiment] was carried out in exactly the same manner as in Example 1, except that a 20 mφ disc formed at a pressure of The number of repetitions to date was 481. The energy density of this battery was 130 W-hr/K9, and the maximum discharge efficiency was 100%. In addition, when the battery was left charged for 62 hours, its self-discharge rate was 2.7%.
Met.

Example 3 [Battery Experiment 〕of(
It became 1. As a result, the number of repetitions until the charging/discharging efficiency decreased to 60% (615 times) was recorded.The energy density of this battery was 204 W・hr/Kg,
The discharge efficiency was 100%. Also, you can use it for 6 hours while it is charged.
When left for 2 hours, the self-discharge rate was 1.6%.

Examples 4 to 5, Comparative Example [Oxidation] was carried out in exactly the same manner as in Example 1, except that the same moles of the monomers shown in the table were used as copolymerization components instead of thiophene used as copolymerization components in Example 1. [Production of copolymer] and [Battery experiment] were conducted. Similarly, for the comparative example that does not use a copolymer component, row 4i 1
．． The results are shown in the table.

table

[Brief explanation of drawings]

The figure is a schematic cross-sectional view of a battery cell for measuring characteristics of a non-aqueous secondary battery, which is an 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 polypropylene diaphragm 5... Positive electrode 6... Platinum wire mesh collection for positive electrode Electric body 7...Positive lead wire 8...Teflon container Patent applicant Showa Denko Co., Ltd. Hitachi, Ltd.

Claims (1)

[Claims] In a non-aqueous secondary battery that has a positive electrode, a negative electrode, and a non-aqueous electrolyte as main components, the positive electrode is formed by the following general formula (a), (
It is characterized by using an oxidized copolymer of an aniline compound containing 1 to 50 mol% of at least one compound selected from the heterocyclic compounds represented by b) and (c) and the heterocyclic compound. A non-aqueous secondary battery. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R', R'' and R'' are alkyl groups having 1 to 10 carbon atoms, and X, Y and Z are 0, 1 or 2. ]