JP2001131246A - Polyelectrolyte and electric device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyelectrolyte capable of improving a transference number of a charge carrier ion, and an electrical device using the same. SOLUTION: This polyelectrolyte comprises a polymer compound bearing a tetravalent borom atom in its skeleton, preferably a polymer compound having a structural unit represented by formula I in the molecule. In formula I, Y is a residue of a polymerizable functional group; and R is a group having a mol.wt. of at least 40 and capable of bonding to the above polymerizable functional group and the boron atom; Ra, Rb and Rc are the same or different and are each a group capable of bonding to the boron atom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer electrolyte and an electric device using the same, and more specifically, an electrode is joined via a polymer electrolyte such as a lithium battery. The present invention relates to an electric device such as a battery and a polymer electrolyte suitably used for the electric device.

[0002]

2. Description of the Related Art Since the development of high-voltage, high-capacity batteries, various types of polymer electrolytes have been proposed.
However, polymer electrolytes have an ion conductivity lower than that of aqueous electrolytes by one digit or more, and polymer electrolytes using, for example, polyethylene glycol have disadvantages such as low transfer of charge carrier ions and low transport number. Attempts have been made to improve using various techniques.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a polymer electrolyte capable of improving the transport number of charge carrier ions, and an electric device such as a battery using the polymer electrolyte. That is the task.

[0004]

The polymer electrolyte of the present invention comprises a polymer compound having a tetravalent boron atom in a polymer skeleton in order to solve the above-mentioned problems.

The polymer compound preferably has a structural unit represented by the following general formula (1) in the molecule.

[0006]

Embedded image In the formula (1), Y represents a residue of a polymerizable functional group, and R represents a group having a molecular weight of 40 or more and capable of bonding to the polymerizable functional group and a boron atom. Ra, Rb, and Rc may be the same or different from each other, and each represents a group capable of bonding to a boron atom.

The polymer compound is also preferably a copolymer further having a structural unit represented by the following general formula (2).

[0008]

Embedded image In the formula (2), Y represents a residue of a polymerizable functional group, Z represents a residue of an active hydrogen compound, and R ′ represents 2 having a molecular weight of 150 or more.
And k represents an integer of 2 to 6.

The above-mentioned polymer electrolyte may further contain an aprotic solvent and / or an electrolyte salt, if necessary.

[0010] A secondary battery of the present invention uses any of the above-mentioned polymer electrolytes.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below, but the present invention is not limited to these.

1. Polymer Electrolyte As described above, the polymer electrolyte of the present invention contains a polymer compound having a tetravalent boron atom in the molecular skeleton, and the polymer compound is preferably represented by the general formula (1). It has the structural unit represented in the molecule.

In the general formula (1), the residue of the polymerizable functional group represented by Y is not particularly limited, but preferred examples thereof include acryloyl, methacryloyl, allyl, vinyl, glycidyl. And a residue such as a group.

R in the general formula (1) is not particularly limited either, but is preferably an alkyldiol residue or a copolymer of the compounds (A) and (B) represented by the following formula.

[0015]

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Further, in the general formula (1), Ra, Rb, R
c represents a hydrogen atom, a halogen atom, or a monovalent group, and examples of the monovalent group include an alkyl group, an alkoxy group, an aryl group, an alkenyl group, an alkynyl group, an aralkyl group, a cycloalkyl group, Cyano group, hydroxyl group, formyl group, aryloxy group, alkylthio group,
Arylthio group, acyloxy group, sulfonyloxy group, amino group, alkylamino group, arylamino group,
Carboxyamino group, oxysulfonylamino group, sulfonamide group, oxycarbonylamino group, ureido group,
Acyl group, oxycarbonyl group, carbamoyl group, sulfonyl group, sulfinyl group, oxysulfonyl group, sulfamoyl group, carboxylic acid group, sulfonic acid group, phosphonic acid group, heterocyclic group, -B (R ¹ ) (R ^m ), −OB (R ¹ ) (R
^m ) or —OSi (R ¹ ) (R ^m ) (R ⁿ ). Here, R ¹ , R ^m and R ⁿ each represent a hydrogen atom, a halogen atom, or a monovalent group, and examples of the monovalent group include an alkyl group, an alkoxy group, an aryl group, an alkenyl group,
Alkynyl group, aralkyl group, cycloalkyl group, cyano group, hydroxyl group, formyl group, aryloxy group, alkylthio group, arylthio group, acyloxy group, sulfonyloxy group, amino group, alkylamino group, arylamino group, carboxyamino group , Oxysulfonylamino group, sulfonamide group, oxycarbonylamino group, ureido group, acyl group, oxycarbonyl group, carbamoyl group, sulfonyl group, sulfinyl group,
Examples include an oxysulfonyl group, a sulfamoyl group, a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, a heterocyclic group, and derivatives thereof. In the formula (1), Ra, R
b and Rc may combine with each other to form a ring, and this ring may have a substituent. Further, each group may be substituted by a substitutable group.

As described above, the polymer compound contained in the polymer electrolyte of the present invention preferably further has a structural unit represented by the general formula (2) in the molecule.

In the general formula (2), the polymerizable functional group residue represented by Y is not particularly limited, but preferred specific examples include those described for Y in the general formula (1). Similar ones can be mentioned.

The active hydrogen compound residue represented by Z is not particularly limited, and examples thereof include residues of ethylene glycol, glycerin, trimethylolethane, diglycerin, pentaerythritol and the like. k represents an integer of 2 to 6, and preferably 2 to 4.

The divalent group represented by R 'is also preferably a copolymer of compounds (A) and (B) represented by the following formula, and the molecular weight is preferably from 150 to 1.7 million. .

[0021]

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Further, it is particularly preferable that R 'is represented by the following formula.

[0023]

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The polymer electrolyte of the present invention contains one or more of the above-mentioned polymer compounds as essential components, and further contains the following electrolyte salts and / or solvents as appropriate. .

As the electrolyte salt, a lithium salt is preferable, and examples thereof include LiBF ₄ , LiPF ₆ , LiClO ₄ , LiA
sF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂
F ₅ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiCl, LiF, LiB
r, LiI, and derivatives thereof. One of these lithium salts may be used alone, or two or more thereof may be used in combination.

The concentration of the electrolyte salt is preferably 10 mol /
kg or less, more preferably 6.0 mol / kg or less.

[0027] The solvent is preferably an aprotic solvent, examples of which include carbonates, lactones,
Examples include ethers, sulfolanes, and dioxolanes. One of these non-aqueous solvents may be used alone, or two or more thereof may be used in combination.

The mixing ratio of the polymer compound and the solvent is by weight.
1/99 to 99/1, preferably 5/95 to 95/5, more preferably 10/90 to 90/10.

2. Electric Device The battery of the present invention is one in which a positive electrode and a negative electrode are joined via any one of the above polymer electrolytes.

Here, a composite metal oxide capable of inserting and extracting lithium ions is used for the positive electrode, and examples thereof include lithium cobaltate, lithium nickelate, lithium manganate, and vanadium pentoxide. Can be

A material capable of reversibly occluding and releasing lithium metal, a lithium alloy or lithium ions is used for the negative electrode. Examples of such a material include carbon.

[0032]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[Preparation of Monomer (Compound (B))] Monomer A Starting material 1 mol of ethylene glycol monobutyl ether
After adding 0.01 mol of potassium hydroxide to the flask and performing nitrogen replacement while stirring, the pressure in the system was reduced using a vacuum pump. Next, the temperature was raised to 120 ° C., and the reaction was carried out using 1 mol of ethylene oxide as a monomer. After the completion of the reaction, the system was cooled to room temperature, and sodium methylate 1.1 was cooled.
A methanol solution of mol was added, and the temperature was slowly raised to 50 ° C. while reducing the pressure. After the methanol was completely removed, 1.2 mol of epichlorohydrin was added and reacted for 4 hours. After the completion of the reaction, an adsorption treatment was carried out, followed by dehydration under reduced pressure and filtration to obtain a target product.

Monomer B The desired product was obtained in the same manner as in Monomer A except that ethylene glycol monomethyl ether was used as a starting material and 9 mol of ethylene oxide was used as a monomer.

Monomer C The desired product was obtained in the same manner as in Monomer A except that ethylene glycol monopropyl ether was used as a starting material and 2 mol of ethylene oxide was used as a monomer.

Monomer D The desired product was obtained in the same manner as in Monomer A except that ethylene glycol monoethyl ether was used as a starting material and 49 mol of ethylene oxide was used as a monomer.

Monomer E The desired product was obtained in the same manner as in Monomer A except that ethylene glycol monomethyl ether was used as a starting material and 9 mol of ethylene oxide was used as a monomer.

[Production of Compounds A-1 to A-10] Compound A-1 2 mol of 1,4-butanediol, 2 mol of acrylic acid, 0.1 ml of sulfuric acid, and 0.001 mol of hydroquinone are dissolved in 100 ml of toluene, and water produced is removed. While refluxing for 4 hours. After completion of the reaction, the solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography using acetone as an eluent to obtain 4-hydroxybutyl acrylate. Acrylic acid 4-hydroxybutyl ester obtained
1 mol, 1 mol of catechol, and 1 mol of borane were reacted in dichloromethane at room temperature, and 1 mol of LiBr was added and dissolved to obtain the desired product.

Compound A-2 8-hydroxyoctyl acrylate was obtained by using 1,8-octanediol instead of 1,4-butanediol. 1 mol of the obtained 8-hydroxyoctyl acrylate, 1 mol of salicylic acid, and 1 mol of borane were reacted in dichloromethane at room temperature, and 1 mol of MeOLi was added and dissolved to obtain the desired product.

Compound A-3 1 mol of potassium hydroxide was added to 500 g of toluene, the atmosphere was replaced with nitrogen while stirring, and the pressure inside the system was reduced using a vacuum pump. Elevated temperature to 120 ° C and ethylene oxide as monomer
The reaction was carried out using 220 mol. After the completion of the reaction, the temperature in the system is cooled to room temperature, and sodium methylate 1.1 mol
Was added, and the temperature was slowly raised to 50 ° C. while reducing the pressure. After completely removing methanol, allow to cool and add 1 kg of toluene, and then add 1 mol of acrylic acid chloride.
Was added and reacted for 4 hours. After performing acid-alkali adsorption treatment, the mixture was filtered, and toluene was removed under reduced pressure to obtain a monol having a polymerizable functional group. Monol obtained 1
1 mol of 2,3-naphthalene diol and 1 mol of borane were reacted in dichloromethane at room temperature, and 1 mol of LiCl was added and dissolved to obtain the desired product.

Compound A-4 Using 240 mol of propylene oxide as a monomer,
A monol having a polymerizable functional group was synthesized in the same manner as in Compound A-1, except that methacrylic acid chloride was used instead of acrylic acid chloride. Monol obtained 1
mol, 1 mol of biphenyl-2,2'-diol and 1 mol of borane were reacted in dichloromethane at room temperature, and 1 mol of LiBr was added and dissolved to obtain the desired product.

Compound A-5 30 mol of ethylene oxide and 8 mol of 1,2-epoxyhexane
Monool having a polymerizable functional group was synthesized in the same manner as in Compound A-1, except that l was used as a monomer and allyl chloride was used instead of acrylic acid chloride. 1 mol of the obtained monol, 1 mol of malonic acid and 1 mol of borane were reacted in dichloromethane at room temperature, and 1 mol of LiI was added.
The desired product was obtained by dissolving.

Compound A-6 A monol having a polymerizable functional group was synthesized in the same manner as in Compound A-1, except that 4 mol of ethylene oxide was used as a monomer and vinyl chloride was used instead of acrylic acid chloride. 1 mol of the obtained monol, 40 t-BuOLi
Dissolved in ethylene glycol dimethyl ether at
A product obtained by reacting 3 mol of fluorophenol and 1 mol of borane in dichloromethane at room temperature was added to obtain the desired product.

Compound A-7 A monol having a polymerizable functional group was synthesized in the same manner as in the compound A-3 except that 240 mol of the monomer A was used as a monomer. The resulting monol (1 mol, t-BuOLi) was dissolved in ethylene glycol dimethyl ether at 40 ° C.
A product obtained by reacting 3 mol of 1-trifluoroethanol with 1 mol of borane in dichloromethane at room temperature was added to obtain the desired product.

Compound A-8 A monol having a polymerizable functional group was synthesized in the same manner as in Compound A-4 except that 15 mol of ethylene oxide and 5 mol of monomer B were used as monomers. 1 mol of the obtained monol and t-BuOLi were dissolved in ethylene glycol dimethyl ether at 40 ° C, and 3 mol of hexafluorophenol was dissolved.
And a product obtained by reacting 1 mol of trichloroborane with dichloromethane at room temperature was added to obtain the desired product.

Compound A-9 A monol having a polymerizable functional group was synthesized in the same manner as in Compound A-5 except that 1 mol of ethylene oxide and 1 mol of monomer C were used as monomers. The resulting monol
1 mol, t-BuOLi was dissolved in ethylene glycol dimethyl ether at 40 ° C, and the product of reacting 3 mol of 1,1,1,3,3,3-hexafluoro-2-propanol and 1 mol of borane in dichloromethane at room temperature was added. To obtain the desired product.

Compound A-10 A monol having a polymerizable functional group was synthesized in the same manner as in Compound A-4 except that 10 mol of ethylene oxide and 2 mol of monomer E were used as monomers. 1 mol of the obtained monool, t-BuOLi was dissolved in ethylene glycol dimethyl ether at 40 ° C., and 2-trifluoromethyl-1,1,1,3,
3,3-hexafluoro-2-propanol 3mol and borane 1mo
The reaction product of l with dichloromethane at room temperature was added to obtain the desired product.

[Production of Compounds B-1 to B-10] Compound B-1 Starting material: 0.5 mol of ethylene glycol and potassium hydroxide
0.01 mol was added, the atmosphere was replaced with nitrogen while stirring, and the system was evacuated using a vacuum pump. Next, the temperature was raised to 120 ° C., and the reaction was carried out using 38000 mol of ethylene oxide as a monomer. After completion of the reaction, the system was cooled to room temperature, a methanol solution of 1.1 mol of sodium methylate was added, and the temperature was slowly raised to 50 ° C. while reducing the pressure. After completely removing methanol and allowing to cool, 1 kg of toluene was added, and 1 mol of acrylic acid chloride was added, followed by a reaction for 4 hours. After performing an acid / alkali adsorption treatment, the mixture was filtered, and toluene was removed under reduced pressure to obtain the desired product.

Compound B-2 The desired product was obtained in the same manner as in Compound B-1, except that 0.33 mol of glycerin was used as a starting material, 28000 mol of propylene oxide was used as a monomer, and methacrylic acid chloride was used instead of acrylic acid chloride. Was.

Compound B-3 Compound B-1 was prepared except that 0.25 mol of diglycerin was used as a starting material, 150 mol of ethylene oxide and 600 mol of 1,2-epoxyhexane were used as monomers, and allyl chloride was used in place of acrylic acid chloride. Was obtained in the same manner as described above.

Compound B-4 In the same manner as in Compound B-1, except that 0.5 mol of ethylene glycol was used as a starting material, 2 mol of ethylene oxide and 1 mol of butylene oxide were used as monomers, and vinyl chloride was used instead of acrylic acid chloride. The desired product was obtained.

Compound B-5 The desired product was obtained in the same manner as in Compound B-1, except that 0.33 mol of glycerin was used as a starting material, and 300 mol of ethylene oxide and 20 mol of 1,2-epoxypentane were used as monomers.

Compound B-6 The desired product was obtained in the same manner as in Compound B-1, except that 600 mol of monomer A was used as a monomer.

Compound B-7 The desired product was obtained in the same manner as in Compound B-2 except that 50 mol of ethylene oxide and 15 mol of monomer B were used as monomers.

Compound B-8 The desired product was obtained in the same manner as in Compound B-3, except that 1 mol of ethylene oxide and 1 mol of monomer C were used as monomers.

Compound B-9 The desired product was obtained in the same manner as for Compound B-4, except that 1600 mol of ethylene oxide and 400 mol of monomer D were used as monomers.

Compound B-10 The desired product was obtained in the same manner as in Compound B-5, except that 10 mol of ethylene oxide and 10 mol of monomer E were used as monomers.

Compounds A-1 to A-1 obtained above
0 and the structures of compounds B-1 to B-10 are as shown in the following chemical formulas and tables.

[Structures of Compounds A-1 to A-10]

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[0060]

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[0061]

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[Structures of Compounds B-1 to B-10]

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[0063]

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[0064] [polyelectrolyte preparation Example 1 Compound A-1 1 g and _{B-10 9g, LiBF 4 1mol} / kg, azobisisobutyronitrile (AIBN) and 0.01 g .gamma.-butyrolactone (GBL) 1.2 g After melting at 40 ° C and pouring between glass plates, leave at 80 ° C for 2 hours to obtain thickness.
A 500 μm polymer electrolyte was obtained.

Example 2 Compounds A-22 and B-88, LiPF ₆ 0.01 mol / kg, AIB
0.01 g of N was dissolved in 0.2 g of acetonitrile at 40 ° C., poured into a glass plate, left at 80 ° C. for 2 hours, and acetonitrile was distilled off under reduced pressure to obtain a polymer electrolyte having a thickness of 500 μm.

Examples 3 to 9 Polymer electrolytes were obtained in the same manner as in Example 2 except that the kinds and amounts of compounds and salts shown in Table 1 below were used.

Examples 10 to 12 Polymer electrolytes were obtained in the same manner as in Example 1 except that the types and amounts of the compounds, salts and aprotic solvents shown in Table 1 below were used.

Comparative Examples 1 and 2 A polymer electrolyte was obtained in the same manner as in Example 2 except that the types and amounts of compounds and salts shown in Table 1 below were used.

Comparative Example 3 1 g of polyethylene oxide (PEO) having a molecular weight of 1,000,000, LiBF
₄ 1 mol / kg was dissolved in 0.2 g of acetonitrile at 40 ° C. and poured between glass plates, and then acetonitrile was distilled off under reduced pressure to obtain a 500 μm-thick polymer electrolyte.

[Measurement of Lithium Ion Transport Number] The polymer electrolytes obtained in the above Examples and Comparative Examples were punched into a circular sheet of 13φ, sandwiched between lithium metal electrodes of the same diameter, and the lithium ion transport number was measured by a DC polarization method. It was measured. The results are shown in Table 1.

[0071]

[Table 1]

[0072]

According to the polymer electrolyte of the present invention, the charge carrier ion transport number is greatly improved. This is because the transport number is the rate at which anions and cations are transported, and when the anions become immobile due to being fixed to the polymer chain, as a result, the rate at which cations are transported is relatively improved. It is believed that there is.

Therefore, by using the polymer electrolyte of the present invention, for example, it is possible to obtain a battery having a higher voltage and a higher capacity than the conventional one.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 1/06 H01B 1/06 A 1/12 1/12 Z H01M 10/40 H01M 10/40 B F term (Ref.)

Claims (6)

[Claims] 1. A polymer electrolyte comprising a polymer compound having a tetravalent boron atom in a polymer skeleton. 2. The polymer electrolyte according to claim 1, wherein the polymer compound has a structural unit represented by the following general formula (1) in the molecule. Embedded image In the formula (1), Y represents a residue of a polymerizable functional group, and R represents a group having a molecular weight of 40 or more and capable of bonding to the polymerizable functional group and a boron atom. Ra, Rb, and Rc may be the same or different from each other, and each represents a group capable of bonding to a boron atom. 3. The polymer electrolyte according to claim 2, wherein the polymer compound is a copolymer further having a structural unit represented by the following general formula (2). Embedded image In the formula (2), Y represents a residue of a polymerizable functional group, Z represents a residue of an active hydrogen compound, and R ′ represents 2 having a molecular weight of 150 or more.
And k represents an integer of 2 to 6. 4. The polymer electrolyte according to claim 1, further comprising an aprotic solvent. 5. The method according to claim 1, further comprising an electrolyte salt.
The polymer electrolyte according to any one of items 1 to 4, wherein 6. A secondary battery using the polymer electrolyte according to any one of claims 1 to 5.