JPH10265674A - Polymer compound composite material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polymer compound composite material as a solid electrolyte being noncorrosive and stable for a long time and having high ionic conductivity by converting an ionic liquid being a polymer compound and comprising a mixture of a lithium salt with an onium salt of a cyclic amidine or pyridine into a solid. SOLUTION: The polymer compound used is desirably a synthetic polymer compound such as a polymethyl methacrylate polymer, a polyacrylonitrile, a polyethylene oxide or an ionene polymer capable of converting an ionic liquid into films or castings. The ionic liquid used is a mixture of a lithium salt with an onium salt of a cyclic amidine or pyridine. The lithium salt is desirably a lithium salt of an organic acid or of an inorganic acid such as bis(trifluoromethylsulfonyl)imide acid lithium salt, LiBF4 . The other component of the ionic liquid comprises a cation of a cyclic amidine of formula I or a cation of pyridine of formula II and an anion being one of an organic carboxylic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polymer compound complex and a method for producing the same. For more information,
The present invention relates to a polymer compound composite that can be used as a solid electrolyte for an electrochemical device and an antistatic material and an electrostatic shielding material for electronic devices.

[0002]

2. Description of the Related Art Conventionally, as an electrolyte of an electrochemical device such as a lithium primary battery, a lithium secondary battery, an electrolytic capacitor, an electric double layer capacitor, and an electrochromic display element, for example, gamma-butyrolactone, N, N-dimethyl For example, an electrolytic solution in which an ionic compound as an ionogen such as lithium perchlorate, tetraethylammonium borofluoride, or tetramethylammonium phthalate is dissolved in a liquid solvent such as formamide, propylene carbonate, or tetrahydrofuran is used.

[0003] However, the electrolytic solution has a drawback that it easily leaks, is easily volatilized, and lacks long-term reliability. On the other hand, the solid electrolyte does not have such a drawback, and when used in the above-mentioned electrochemical device, the manufacturing process can be simplified, and the device itself can be reduced in size and weight. In particular, polymer solid electrolytes are excellent in flexibility, light weight, elasticity, thin film formability, processability, transparency, etc., and are applied to high-energy batteries for electric vehicles and built-in batteries in thin products such as IC cards. (Watanabe, Electrochemistry, 62, 304, 1994)
Year).

The above-mentioned solid polymer electrolyte is a solid electrolyte obtained by compounding a polyalkylene ether polymer compound such as polyethylene oxide or polypropylene oxide with an alkali metal salt such as lithium sulfonimide, LiClO ₄ or LiCF ₃ SO _3. (Salt-in-P
polymer type) has been studied, but it has been revealed that ionic conductivity is caused by thermal motion of polymer chains,
Although various attempts such as amorphization have been made,
Technical limits have been reached in terms of ion conductivity and shape stability.

[0005] Therefore, a ionic liquid is responsible for ionic conductivity and a polymer compound is responsible for mechanical properties. A polymer solid electrolyte of a function separation type (Polymer-in-Salt).
The concept of type was proposed independently by two research groups. One is N-, which is known as an ionic liquid.
A complex of butylpyridinium halide and aluminum halide immobilized with a polymer compound (Watanabe et al., JCS Chem. Commun., 9
29, 1993). Another is a supercooled liquid in which two or more lithium salts are mixed and immobilized with a polymer compound (CA Angell et al., Nat.
ure, 362, 137, 1993). However, the former complex has a problem in corrosiveness due to halide ions, and the latter complex crystallizes with time because a thermodynamically unstable supercooled liquid is immobilized. There is a problem.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polymer compound composite as a solid electrolyte which is non-corrosive, stable over time, and has high ionic conductivity.

[0007]

The present invention relates to a polymer compound composite obtained by solidifying an ionic liquid (B) with a polymer compound (A), wherein the ionic liquid (B) is a lithium salt ( a polymer compound complex comprising a mixture of b1) and an onium salt of a cyclic amidine or pyridine (b2).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Polymer compound (A): The polymer compound used in the present invention is a compound which can solidify an ionic liquid into a film or a cast product, and is preferably a synthetic polymer compound. Specifically, polyvinyl polymer compounds such as polyvinyl chloride, polyacrylonitrile, polymethyl methacrylate, and polyvinylidene fluoride; polyether polymer compounds such as polyoxymethylene, polyethylene oxide, and polypropylene oxide; nylon 6, nylon 66, a polyester-based polymer compound such as polyethylene terephthalate, a polycarbonate-based polymer compound, an ionene-based polymer compound, and the like. Polymethylmethacrylate-based polymers, polyacrylonitrile, polyethylene oxide, and ionene Preferred are high molecular compounds.

Ionic liquid (B): In the present invention,
The ionic liquid (B) comprises a lithium salt (b1) and a cyclic amidi.
Or a mixture with pyridine or onium salt of pyridine (b2)
I do. As the lithium salt, a lithium salt of an organic acid or
And lithium salts of inorganic acids. Lithium salt of organic acid
Examples include, for example, lithium acetate, trifluoroacetic acid
Titanium, lithium benzoate, trifluoromethanesulfo
Lithium phosphate, lithium p-toluenesulfonate, bis
Lithium (trifluoromethylsulfonyl) imidate,
Lithium tris (trifluoromethylsulfonyl) carboxylate
And lithium salts of inorganic acids, for example,
If LiNO_Three, LiSCN, LiClO _Three, LiCl
O_Four, LiBF_Four, LiPF₆, LiAsF₆, LiS
bF₆And the like. Preferred lithium among these
The salt is bis (trifluoromethylsulfonyl) imidic acid
Lithium, tris (trifluoromethylsulfonyl) charcoal
Lithium oxide, LiBF_Four, LiPF_FourEtc. lithium salt
It is. The component of the other ionic liquid (B) has the formula (I)
Cation of cyclic amidine represented by

[0010]

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[Wherein R ¹ and R ³ each independently represent an alkyl group having 1 to 5 carbon atoms, and R ² represents hydrogen or 1 to 5 carbon atoms.
Q is an alkylene having 2 to 5 carbon atoms,
Represents arylene or alkenylene. Or a cation of pyridine represented by the formula (II)

[0012]

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[Wherein R ⁴ represents an alkyl group having 1 to 6 carbon atoms, and R ⁵ represents a methyl or ethyl group. ] And an anion. Examples of anions include bis (trifluoromethylsulfonyl) imidic acid, perchloric acid, tetrafluoroboric acid, hexafluorophosphoric acid, tris (trifluoromethylsulfonyl) carbonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid, and propionic acid And organic carboxylic acids such as butyric acid, isobutyric acid, maleic acid, phthalic acid, benzoic acid, salicylic acid, succinic acid, and apicin acid.

As the onium cation of cyclic amidine or pyridine, 1,3-dialkylimidazolium,
Those having an imidazole ring such as 1,2,3-trialkylimidazolium, those having an imidazoline ring such as 1,3-dialkyl-imidazolinium, and those having a pyrimidine ring such as 1,3-dialkyltetrahydropyrimidinium And cyclic imine compounds such as those having a diazabicyclo ring such as 1,5-diazabicyclo [4.3.0] nonene-5 and those having a pyridine ring such as 1-alkylpyridinium.

Specific examples of the onium salt of cyclic amidine or pyridine include 1-ethyl-3-methylimidazolium tetrafluoroborate, 1,2-dimethyl-3-
Ethyl imidazolium tetrafluoroborate, 1,3
-Dimethyl-imidazolinium tetrafluoroborate, 1-ethylpyridinium tetrafluoroborate,
1,5-diazabicyclo [4.3.0] nonene-5-methyltetrafluoroborate, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-butylpyridinium bis (trifluoromethylsulfonyl) Imide, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3
-Methylimidazolium trifluoroacetate.

The ionic liquid component lithium salt (b1) and a cyclic amidine or pyridine onium salt (b
The compounding ratio with 2) is within a range compatible with each other, and generally, the lithium salt (b1) is used in an amount of 0.1 to 99 parts by weight, preferably 1 to 99 parts by weight, based on 100 parts by weight of the onium salt. 30
Used in parts by weight.

Polymer compound composite: The polymer compound composite is prepared by directly adding the polymer compound (A) to the above ionic liquid (B), heating and dissolving the mixture, cooling it, or forming it by an appropriate organic compound. It is obtained by mixing and molding both in a solvent, and then distilling off the solvent by a method such as drying under reduced pressure. Further, in the ionic liquid, a raw material monomer of the polymer compound is mixed, a polymerization initiator is added, and the raw material is subjected to heat polymerization or condensation reaction to obtain a polymer compound complex.

The heating temperature is preferably from room temperature to 150 ° C. Examples of the polymerization initiator include diacyl peroxides such as benzoyl peroxide, peroxides such as cumene hydroperoxide and hydrogen peroxide, azo compounds such as 2,2-azobisisobutyronitrile, and dibenzoyl disulfides. Examples thereof include disulfides and sulfinic acids such as p-toluenesulfinic acid.

Ionic liquid (B) and polymer compound (A)
May be any mixing ratio as long as they are compatible with each other, but generally, the amount of the polymer compound (A) used is 100 parts by weight of the ionic liquid (B). 1 to 99 parts by weight, preferably 5 to 60 parts by weight based on parts. The polymer compound composite has no problem of liquid leakage, is not corrosive, and is stable, and thus is a solid electrolyte for an electrochemical device that can withstand long-term reliability. Further, it can be used as an antistatic material or an electrostatic shielding material for electronic devices by utilizing its ionic conductivity.

[0020]

The present invention will be described in more detail with reference to the following examples. Example 1 In a glove box under an argon atmosphere, polyacrylonitrile (PAN: average molecular weight 86,000) 100
mg, 1-ethyl-3-methylimidazolium tetrafluoroborate 384 mg, lithium tetrafluoroborate 16 mg and N, N-dimethylformamide (D
MF) was added, and the mixture was heated and stirred at 95 ° C. for 30 minutes to obtain a clear solution.

After allowing this solution to cool, it is heated under reduced pressure (70 ° C.,
The solvent DMF was distilled off at 1 mmHg) to obtain a polymer composite thin film having a thickness of 60 μm. 1 cm in diameter and 1 m in thickness between stainless steel electrodes which have been polished with this polymer compound composite.
m, using a sealed conductivity measuring cell, an impedance analyzer and a thermostat, with a frequency range of 5 to 13 MHz and a temperature range of 100.
Oscillation level 500mV at ~ 0 ° C
And the ionic conductivity was measured.

The ionic conductivity at 30 ° C. is 1.6 ×
It was 10 ^-3 S / cm. Further, the tensile strength was measured and found to be 70 kg / cm ² . No corrosion of stainless steel was observed after storage for 6 months. Example 1
The ionic conductivity of the polymer compound composite thin film obtained at the above was measured at different temperatures and shown in FIG. 1 as a temperature-ion conductivity correlation diagram of the polymer compound composite.

Example 2 In a glove box under an argon atmosphere, polyethylene oxide (PEO: average molecular weight 600,000) 8
4 mg, 1-ethyl-3-methylimidazolium tetrafluoroborate (258 mg), lithium tetrafluoroborate (10.8 mg) and N, N-dimethylformamide (DMF) (5.5 g) were added, and the mixture was heated and stirred at 95 ° C. for 30 minutes to give a transparent solution. A solution was obtained.

After allowing the solution to cool, the solvent D
The MF was distilled off to obtain a polymer composite thin film having a thickness of 100 μm.
Was. The thin film of this polymer compound composite at 30 ° C.
The on-conductivity is 1.1 × 10^-3S / cm. Ma
The tensile strength is 60 kg / cm ^TwoMet. 6 months storage
No subsequent corrosion of stainless steel was observed. The implementation
With respect to the polymer compound composite thin film obtained in Example 2,
The ionic conductivity at different temperatures was measured and
FIG. 1 shows a correlation diagram between the temperature of the coalescence and the ionic conductivity.
Was.

Comparative Example 1 In a glove box under an argon atmosphere, PAN20 was
0 mg, triethylmethylammonium benzoate 332
mg, lithium acetate 26.4 mg, LiTFSI
4 mg and 5.5 g of DMF were added, and the mixture was heated and stirred at 95 ° C. for 30 minutes to obtain a clear solution. After allowing this solution to cool, DMF as a solvent was distilled off under reduced pressure while heating (70 ° C., 1 mmHg) to obtain a thin film of a polymer composite. The ionic conductivity of this thin film of the polymer compound composite at 30 ° C. was 3.2 × 10 ⁻⁶ S /
cm.

[0026]

The polymer compound complex of the present invention has no problem of liquid leakage, is not corrosive, and is stable, so it can withstand long-term reliability, and can be used for lithium primary batteries, lithium secondary batteries, Electrolytic capacitors, electric double layer capacitors,
It is suitable as a solid electrolyte for an electrochemical device such as an electrochromic display element. Further, by utilizing the ionic conductivity, it can be used as an antistatic material or an electrostatic shielding material for electronic devices.

[Brief description of the drawings]

FIG. 1 is a correlation diagram of temperature-ionic conductivity of a polymer compound composite.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 69/00 C08L 69/00 71/00 71/00 77/00 77/00 H01B 1/12 H01B 1/12 Z // H01M 6/18 H01M 6/18 E 10/40 10/40 B (72) Inventor Ayako Yonei 3-1-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Pref.

Claims (9)

[Claims] 1. A polymer compound complex obtained by solidifying an ionic liquid (B) with a polymer compound (A), wherein the ionic liquid (B) is composed of a lithium salt (b1) and a cyclic amidine or pyridine. A polymer compound complex comprising a mixture with an onium salt (b2). 2. An onium salt (b) of an ionic liquid (B)
2) has the formula (I) [Wherein, R ¹ and R ³ each independently represent an alkyl group having 1 to 5 carbon atoms, R ² represents hydrogen or an alkyl group having 1 to 5 carbon atoms, and Q represents an alkylene having 2 to 5 carbon atoms. , Arylene or alkenylene. Or a cyclic amidine represented by the formula (II): [In the formula, R ⁴ represents an alkyl group having 1 to 6 carbon atoms, and R ⁵ represents a methyl or ethyl group. The polymer compound complex according to claim 1, which is an onium salt of pyridine represented by the formula: 3. The cyclic amidine has an imidazole ring, 2-
The polymer compound complex according to claim 2, which is a compound having a ring selected from an imidazoline ring, a tetrahydropyrimidine ring, a diazabicyclo ring, and a pyridine ring. 4. An anion constituting an onium salt of the ionic liquid (B) is bis (trifluoromethylsulfonyl)
Imidic acid, perchloric acid, tetrafluoroboric acid, hexafluorophosphoric acid, tris (trifluoromethylsulfonyl)
The polymer compound complex according to claim 1, wherein the complex is at least one selected from carbon acids, trifluoromethanesulfonic acid, trifluoroacetic acid, and organic carboxylic acids. 5. The polymer compound (A) is at least one selected from the group consisting of a polyvillyl polymer, a polyether polymer, a polyamide polymer, a polyester polymer, a polycarbonate polymer and an ionene polymer. The polymer compound complex according to claim 1, which is at least one kind. 6. The polymer compound composite according to claim 1, wherein the polymer compound (A) is used in an amount of 1 to 99 parts by weight based on 100 parts by weight of the ionic liquid (B). 7. The lithium salt (b1) is an onium salt (b
2) The polymer compound composite according to claim 1, which is used in a ratio of 0.1 to 99 parts by weight based on 100 parts by weight. 8. The method for producing a polymer compound complex according to claim 1, wherein the polymer (A) and the ionic liquid (B) are dissolved in a solvent, and then the solvent is removed. 9. The polymer compound composite according to claim 1, wherein an ionic liquid (B) and a polymerization initiator are added to the raw material monomer of the polymer compound (A), and the polymerization is carried out. How to make.