JPS61279060A - 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 a specified aniline family compound and benzene family compound and/or phenol family 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 one or more compounds selected from benzene family compound indicated in the formula (a) and phenol family compound indicated in the formula (b), and benzene family compound and/or phenol compound is used as the positive electrode. The content of the benzene family compound and/or the phenol family compound 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 1] A so-called polymer battery, in which a polymer compound having a conjugated double bond in its main chain is used as an electrode, is expected to be used as a high energy density secondary battery. Many reports have already been made regarding polymer batteries, such as B.G.
Nigley et al., Digital of +A Chemical
Tsunaiati, Chemical Communication, No. 59
4 pages (1979) (P, J, Nigrey et al., J, C
,S,,Chem,Commun,, 197
9゜594): General Electrochemical Society, p. 1651 (1981) (J, F
Electrochem.

Soc, 191N, 1651), Japanese Patent Publication No. 1983
-136469, 57-121168, 59-
No. 3870, No. 59-3a7z@, No. 59-3873, No. 59-19 [1566 bow, No. 59-196573, No. 59-203368@, No. 59-203369, etc. can be mentioned as some of them. .

In addition, 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 (
A.G. Matsuku Diarmid et al., Polymer Preprints, Volume 25, Number 2. Page 248 (1984
year) [^, G, HacDiarmid, etc., Po1l/l
1ler Preprints, Wataru No. 2.248 (
1984)], Sasaki et al., Proceedings of the 50th Annual Conference of the Electrochemical Society, 123 (1983), Collected Proceedings of the 51st Annual Conference of the Electrochemical Society, 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 (iV) 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 the electrode material r1 that satisfies the above four battery performances at the same time, the present inventors found that a specific aniline compound, benzene compound and/or phenol compound By using an oxidized copolymer of
The inventors have discovered that a non-aqueous secondary battery that satisfies the four battery performances described above can be obtained, and have arrived at the present invention.

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 benzene-based compound represented by the following general formula (a>) and a benzene compound represented by the general formula (b) are used as the positive electrode. A non-aqueous dihydride characterized by using an oxidized copolymer of an aniline compound containing 1 to 50 mol% of at least one kind of phenolic compound selected from the benzene compound and/or the phenol compound. Regarding the next battery.

[In the formula, R' and R" are alkyl groups having 1 to 10 carbon atoms, and m and n are 0.1 or 2.] The aniline compound used in the present invention has the general formula [However, in the formula, R is a hydrogen atom or an alkyl group or alkoxy group having 1 to 10 carbon atoms, and × is 1 or 2
It is. ] 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,
3-Methoxy-aniline, 2,3-dimethoxy-aniline, 2,5-dimethoxy-aniline, 3,5-dimethoxy-aniline, 2-ethoxy-aniline, 3-ethoxy-aniline, 2,3-jethoxy -Aniline, 3°5
-Ch-1-xyaniline, 2,5-jethoxy-aniline, and the like. Among these aniline compounds, aniline is preferred.

Specific examples of the benzene compound represented by the general formula (a) used as a copolymerization component of the aniline compound in the present invention include benzene, methylbenzene, ethylbenzene, 0-1m=, p-xylene, etc. Among these, bempine is preferred.

Further, specific examples of the phenol compound represented by the general formula (b) used as a copolymerization component of the aniline compound include phenol, 2-methyl-phenol,
Examples include 3-methyl-phenol and 2,6-dimethylphenol. Among these phenolic compounds, phenol is preferred.

A benzene compound represented by general formula (a) and a general formula (
The phenolic compound represented by b') may be used in combination.

The content of the benzene compound and/or phenol compound in the oxidized copolymer is 1 to 50 mol%, preferably 1 to 30% by mole. /or If the content of the phenolic compound is less than 1 mol%, no copolymerization effect can be obtained,
No effect on improving battery performance was observed. On the other hand, the content of benzene compounds and/or phenolic compounds is 5
If it is more than 0 mol %, a sufficiently high doping rate cannot be obtained, making it difficult to obtain a battery 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 using electrochemical polymerization methods, polymerization of monomers is carried out by anodic oxidation. For that purpose, for example, 2 to 20 m
A current density of A/as 2 is used. Most are 10
A voltage of ~300 volts is applied. The polymerization is preferably carried out in the presence of an auxiliary liquid in which the aniline, benzene and phenolic compounds are soluble. Water or polar organic solvents can be used for this purpose. If you use a solvent that is miscible with water, add a small amount of water to
Good too. Good alternative OFJ agents are alcohols, ethers such as dioxane or hydrofuran, acetone or acetonitrile, benzonilyl, dimethylboramide or N-methylpyrrolidone, but
It is not necessarily limited to these.

The procedure is carried out in the presence of a complexing agent. This includes BF″i, Δsl″i, and ASFi as anions.

Sb Fi , Sb Cl −, PF′; B, C1Oi.

It means a salt containing the groups H3O1 and SO42-.

These salts contain, for example, H+, quaternary ammonium cations, lithium, sodium or potassium as cadions. The use of compounds of this type is known and is not the subject of the present invention. In these compounds, the oxidized copolymer usually contains 20 to 100 mol% of the anionic complexing agent.
It is used in the amount contained.

When producing the oxidized copolymer by a chemical method, for example, a mixture of an aniline compound and a benzene compound and/or a phenol compound is polymerized in an aqueous solution with a strong acid or with an inorganic peroxide such as potassium persulfate. can be done. According to this method, the oxidized copolymer is obtained in the form of a fine powder. Since a 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 produced by various methods.
It will be done. For example, in the case of electrochemical oxidative copolymerization processes, the oxidized copolymer is usually complexed with anions to form a copolymer in the form of the anode used. 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 anionic complexed oxidized copolymers, shaped bodies of any desired 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 jq 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 removing the complexed anion chemically or electrochemically.

The negative electrode used in the nonaqueous secondary battery of the present invention is not particularly limited, and examples thereof include polypyrrole and polypyrrole derivatives, polythiophene and polythiophene derivatives, polyquinoline, boriacene, polyparaphenylene, polyacetylene, etc. 1~, intercalation compounds such as Ti32, alkali metals such as lithium, sodium, lithium-aluminum, etc., or alloys thereof, etc., and among these, preferred are polyacetylene, polyvaphenylene, and lithium-aluminum alloy. I can do it.

The oxidized copolymer and lightning conductive +1 polymer used as the electrode of the secondary battery of the present invention may contain other suitable conductive materials such as carbon black, acetylene black, etc., as well known to those skilled in the art. Metal powder, metal! ! A cloth, carbon fiber, etc. may be mixed.

Further, it may be reinforced with a thermoplastic resin such as polyethylene, modified polyethylene, polypropylene, poly(tetra-rough ethylene), 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.

Alkylene nitrile: Examples, crotonitrile (liquid range, -si, i°C to 120°C) two trialkyl borates, trimethyl borate, (CH30>3 B (liquid range, -29,3°C to 67°C) tetraalkyl Silicates: e.g. detramethyl silicate, (Ct-430)4S
i (boiling point, 121°C) Nitroalkanes: e.g., nitromethane, CH3NO2 (liquid range, -17°C to 100.8°C) Alkylnitrile: e.g., acetonitrile, C+-13ON
(Liquid range, -45°C to 81.6°C) Dialkylamide: e.g., dimethylformamide, IC0N (CH
3) 2 (Liquid range, -60,48℃~149℃) (Liquid range,
-16°C to 202°C) Monocarboxylic acid esters: e.g., ethyl acetate (liquid range,
-83,13~77,06℃) Enlutoester: e.g.
Trimethyl orthoformate, HC(OCH3)3
<boiling point, 103℃) (liquid range, -42~206℃
) 2 dialkyl carbonates, dimethyl carbonate, QC (OCI-13) 2 (liquid range, 2-90°C
) 2 alkylene luponates, propylene carbonate, (liquid range, -48 to 242°C) 2 monoethers, diethyl ether (liquid range, -116 to 34.5°C) Polyethers: examples, 1, 1- and 1 , 2-dimethoxyethane (liquid range, -113, 2 to 64.5°C, respectively)
and -58-83°C) two cyclic ethers, tetrahydrofuran (liquid range, -
65-67°C): 1,3-dioxolane (liquid range, -
95-78°C) 21-B Aromatic M: e.g., nitrobenzene (liquid range, 5.7-210.8°C) Aromatic carboxylic acid halide: e.g., benzoyl chloride (
Liquid range, 0 to 197°C), benzoyl bromide (liquid range, -24 to 218°C) Aromatic sulfonic acid halide: e.g., benzenesulfonyl chloride (liquid range, 14.5 to 251°C) Aromatic phosphonic acid di 2 halides, benzenephosphonyl dichloride (boiling point, 258°C), 2 aromatic thiophosphonic acid dihalides, benzene diophosphonyl dichloride (boiling point, 124°C at 5M) (melting point, 22°C) 3-methylsulfolane (1 point, -1℃) two alkyl sulfonic acid halides, methane sulfonyl chloride (boiling point, 161℃) Alkyl carboxylic acid halides: e.g. range, -96 to 76°C), propionyl chloride (
Liquid range, -94 to 80°C) Saturated heterocyclic compounds: e.g., tetrahydrothiophene (Liquid range, -96 to 121°C): 3-Methyl-2-oxazolidone (melting point, 15.9°C) Dialkyl sulfamic acid halide 2, dimethyl sulfamyl chloride (boiling point, 80°C at 16Illal) 1 and 2 alkyl halosulfones, ethyl chlorosulfonate (boiling point, 151°C) vesicles 1 (1 heterocyclic carboxylic acid halide: e.g. 2 chlorides)
- Furoyl (liquid range, -2 to 173°C), two five-membered vesicular heterocyclic compounds, 1-methylvirol (boiling point, 114
℃), 2,4-dimethylthiazole (boiling point, 144℃)
, furan (liquid range, -85,65~31, 36℃)
, two Nisder and/or halides of dibasic carboxylic acids, ethyl oxalyl chloride (boiling point, 135°C) two mixed alkylsulfonic acid halides/carboxylic acid halides, chlorosulfonylacetyl chloride (boiling point, 98 at 10#Ial) °C) Dialkyl sulfoxide: e.g. dimethyl sulfoxide (liquid range, 18.
4-189℃) dialkyl sulfate: e.g., dimethyl sulfate (liquid range, -31.75-188.5℃)
) Dialkyl sulfite: e.g., dimethyl sulfide (boiling point, 126°C) Alkylene sulfide: e.g., ethylene glycol
Sulfide (liquid range, -11~173℃) Two halogenated alkanes, methylene chloride (liquid range, -
95-40°C), 1,3-dichloropropane (liquid range, -99.5-120.4°C) Among the above, preferred organic solvents are sulfolane, crotonitrile, nitrobenzene, tetrahydrofuran, methyl-substituted tetrahydrofuran, 1,3-dichloropropane (liquid range, -99.5-120.4°C) - dioxolane, 3-methyl-2-oxazolidone, propylene or ethylene carbonate, sulfolane, γ-butyrolactone, ethylene glycol sulfide, dimethylsulfide 1-, 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 make the cathode material highly and efficiently available. be.

Typical cation components of the supporting electrolyte used in the electrolyte of the secondary battery of the present invention include, for example, a gold a cation of a metal whose Pauling electronegativity value does not exceed 1.6, or a metal whose general formula is RMH+. 4-x × or R3E+ (where R is an alkyl group or aryl group having 1 to 10 carbon atoms, M is N, P or As atom, E
is an O or S atom, x is an integer from O to 4), and representative anion components of the supporting electrolyte include, for example, Cjl OM,
PFi, As F's, As F:i.

303 CFi, BF″4. and BR i (however, R
is an alkyl group or aryl group having 1 to 10 carbon atoms), and the like.

A specific example of the supporting electrolyte is LiPFa.

LtSbFo, Li(1!04.LiA3Fe.

CF3303 Li, Li BF4, Li B
(BLI>4.

Li B (Et) 2 (BLI) 2 ,
NaPFa.

NaBF4, NaAsFa, NaB(Bu)4
.

Examples include KB (BIJ)4, KAS Fe, 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 oxidized copolymer used in the positive electrode, the type of cathode, charging conditions, operating temperature, type of supporting electrolyte, type of organic solvent, etc., but in general is 0.5 to 10 mol/
It is preferably within the range of 1. 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 15 mol%, per 1 mol of repeating units of the oxidized copolymer. %.

The dope m 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 a natural membrane may be used. lff
There is no problem in using paper as a diaphragm.

In addition, some of the electrodes used in the secondary battery of the present invention may react with oxygen or water and reduce 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 good voltage flatness during discharge. be. Furthermore, the secondary battery of the present invention is lightweight, compact, and has a high energy density, making it ideal for use in portable devices, electric vehicles, gasoline vehicles, and power storage batteries.

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

Example 1 [Production method of oxidized copolymer] Distilled water, HBF4, aniline and phenol were added to a glass container, and the concentration of HBF4 was 1.5 mol, and the concentrations of aniline and phenol were 081 mol and 0, respectively.
．． W4 was prepared to have a concentration of 1 mol. Two platinum electrodes of 6aR2 were placed in the aqueous solution at a distance of 2 cm, and then electrolysis was carried out at an electric current of 120 amperes/sec while stirring. On this occasion,
An oxidized copolymer of black 4A color was deposited on the anode plate. The coated sunflower was repeatedly washed three times with distilled water and then heated to 70°C.
After vacuum drying, the produced oxidized copolymer film was peeled off from the platinum plate. IR-spectral analysis showed that the resulting oxidized copolymer contained 5.2 mol% phenol.

[Manufacture of film-like acetylene polymer] In a nitrogen atmosphere Q, 1 go of titanium tetrabutoxide was added to a glass reaction vessel with an internal volume of 500 cm, and 30 ai!
A catalyst solution was prepared by dissolving 2.7 d of triethylaluminum in 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 evacuated to stop the polymerization.

After removing the catalyst solution with a syringe under nitrogen atmosphere, -78
It was washed repeatedly with 100ml of purified toluene 5 times while keeping the temperature at °C. The film-like acetylene polymer swollen with toluene was a uniform film-like swollen product in which fibrils were tightly intertwined. Next, this swollen product was vacuum-dried to obtain a reddish-purple film with a metallic luster, a thickness of 180 μm, and a cis-containing FF of 198%. In addition, the bulk density of this film-like acetylene polymer is 0.30 g/cc, and its electrical conductivity (DC four-probe method) is 3.2 x 10-
It was 9Ω-1·cffi-1.

[Battery experiment] Disks with a diameter of 20M were cut out from the aniline and phenol 4-11°C-8 copolymer film and the membranous acetylene polymer obtained by the above method, and used as active materials for the positive and negative electrodes, respectively. , constructed the battery.

The figure is a schematic cross-sectional view of a battery cell for measuring the characteristics of a non-aqueous secondary battery, which is an example of the present invention, in which 1 is a platinum lead wire for the negative electrode, 2 is a platinum wire mesh current collector for the negative electrode with a diameter of 20 am and 80 meshes. 3 is a disc-shaped negative electrode with a diameter of 20 m, 4 is a circular porous polypropylene diaphragm with a diameter of 20 m and is thick enough to be sufficiently impregnated with the electrolyte, 5 is a disc-shaped positive electrode with a diameter of 20 #l, Reference numeral 6 indicates a platinum wire mesh current collector for the positive electrode with a diameter of 20M and 80 meshes, 7 indicates a positive electrode lead wire, and 8 indicates a screw-in 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, and the porous polypropylene diaphragm 4 is placed on top of it, and after sufficiently impregnated with the electrolyte, the negative electrode 3 is placed in the lower part of the recess. They were stacked one on top of the other, and a platinum wire mesh current collector 2 for negative electrode was placed on top of the stack, and a Teflon container 8 was tightened to produce a battery.

As the electrolytic solution, 1 mole of 1iPFe dissolved in tetrahydrofuran distilled and dehydrated according to a conventional method was used.

Using the battery prepared in this manner, the electrical temperature at which the doping load to the positive and negative electrodes corresponds to 50 mol% and 6 mol%, respectively, was raised under a constant current (1.7 mA/crR2) in an argon atmosphere. I drained it and charged it. Immediately after charging, the battery was discharged under a constant current (1.5TrLA/cIR2), and when the battery voltage reached 0.20 V, the battery was charged again under the same conditions as above.A repeated charge/discharge test was conducted. The number of repetitions of charging and discharging was recorded as 564 times until the charging and discharging efficiency decreased to 60%.

The energy density at the fifth repetition is 126W.
-hr/Kg, the maximum discharge efficiency was 100%. 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, Puritin of the Chemical Society of Japan, Vol. 51, p. 2091 (1978
) (Bull, Chem, Soc,
Japan.

51, 2091 (1978)) at 1 tan/cm.
[Battery experiment] was carried out in exactly the same manner as in Example 1, except that a disk shape of 20 mm φ was formed at a pressure of 2 and used as the 91 pole, and as a result, the charging/discharging efficiency decreased to 60%. The number of repetitions until this point was 493. The energy density of this battery was 131 W-hr/lGy, and the maximum discharge efficiency was 100%. Also, when left charged for 62 hours, the self-discharge rate was 2.6%.
Met.

Example 3 [Battery Experiment ) was carried out. As a result, the number of repetitions until the charging/discharging efficiency decreased to 60% was recorded as 606 times. The energy density of this battery was 206 W·hr/Ky, and the maximum discharge efficiency was 100%. Also, it can be used for up to 62 seconds while being charged.
When the battery was left to stand for a while, its self-discharge rate was 1.8%.

Example 4 An oxidized copolymer of aniline and benzene was obtained in exactly the same manner as in Example 1, except that the same mole of benzene was used in place of the phenol used as a copolymerization component in Example 1. IR-spectral analysis revealed that 4.9 mol% of benzene was copolymerized in this oxidized copolymer. [Battery experiment] was carried out in exactly the same manner as in Example 1, except that the oxidized copolymer of aniline and benzene obtained above was used instead of the oxidized copolymer of aniline and phenol used in Example 3. I did it. As a result, the number of repetitions until the charging/discharging efficiency decreased to 60% was 621 times. The energy density of this battery is 202W-hr/
kg, and the maximum discharge efficiency was 100%.

Moreover, the self-discharge rate after 62 hours was 1.9%.

Comparative Example An oxidized polymer of aniline was obtained in exactly the same manner as in Example 1 except that phenol was not used as a copolymerization component. [Battery experiment] was carried out in exactly the same manner as in Example 1 except that this oxidized polymer was used for the positive electrode. As a result, the number of repetitions until the charging/discharging efficiency decreased to 60% was 315 times. The energy density of this battery was 120 W-hr/Ky, and the maximum discharge efficiency was 98%. Moreover, the self-discharge rate after 62 hours was 6.7%.

[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)

[Scope of Claims] A non-aqueous secondary battery having a positive electrode, a negative electrode, and a non-aqueous electrolyte as main components, the positive electrode comprising a benzene-based compound represented by the following general formula (a) and a benzene-based compound represented by the general formula (b). A non-aqueous dihydride characterized by using an oxidized copolymer of an aniline compound containing 1 to 50 mol% of at least one kind of phenolic compound selected from the benzene compound and/or the phenol compound. Next battery. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R' and R'' are alkyl groups having 1 to 10 carbon atoms,
m and n are 0, 1 or 2. ]