JP3321201B2 - Ion conductive polymer electrolyte - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion conductive polymer electrolyte.

[0002]

2. Description of the Related Art Conventionally, ion conductive polymer electrolytes include, for example, an organic polymer electrolyte of polyethylene oxide (PEO), a polyethylene oxide portion and a polypropylene oxide portion of a polyfunctional polyether molecular structure. Is an organic polymer electrolyte contained in a random copolymerization type (for example,
249361), a solid polymer electrolyte comprising an ethylene oxide copolymer containing an ionic compound in a dissolved state (see, for example, JP-A-61-83249), and a thermoplastic homopolymer having no cross-linking or An ion-conductive polymer electrolyte (for example, see Japanese Patent Application Laid-Open No. 55-98480) using a polymer solid substance having plasticity substantially consisting of a branched chain of a copolymer is known.

[0003] However, even if these conventional ion-conductive polymer electrolytes are applied to electrolytes such as batteries, there is a problem that the ion conductivity is insufficient.
To solve this problem, it has been proposed to improve the conductivity by impregnating a polymer with a non-aqueous solvent such as propylene carbonate used in a conventional liquid electrolyte (for example, Japanese Patent Application Laid-Open No. 63-94501). Gazette). Although the conductivity of the solid polymer electrolyte obtained in this way is close to practical use, when the use environment temperature becomes high (60 ° C. or higher), the solvent is evaporated and the performance is remarkably deteriorated. In the case of a closed type such as a battery, there is a risk that the closed system is broken. Therefore, this solid polymer electrolyte cannot be applied to a large battery operated at a high temperature.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide an ion-conductive polymer electrolyte which is safe even at a relatively high temperature and has a high ionic conductivity. To provide.

[0005]

In order to achieve the above-mentioned object, the gist of the present invention is to provide a compound having an average molecular weight of 10 represented by a general formula.
An ion conductive polymer electrolyte characterized in that a soluble electrolyte salt compound is contained in an organic polymer obtained by cross-linking an organic compound having a molecular weight of from 0000 to 20,000.

[0006]

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Wherein Z is an active hydrogen-containing compound residue;
¹ is a group represented by the following general formula (n is an integer of 0 to 25, R is an alkyl group, alkenyl group or aryl group having 1 to 20 carbon atoms); R ² is a hydrogen or methyl group; It consists of an alkyl group, an alkenyl group or an aryl group of Formulas 1 to 20 and a polymerization reactive functional group, and the ratio of the alkyl group, alkenyl group or aryl group is 50 to 50.
98%, and the ratio of the polymerization reactive functional group is 2 to 50%
Where k is an integer of 1 to 12, p is an integer of 1 to 220,
m represents an integer of 1 to 240.

[0008]

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The organic compound represented by the general formula used as a raw material of the organic polymer is a polyether compound obtained by reacting an active hydrogen-containing compound with a glycidyl ether together with an alkylene oxide, and further comprising a polymerization reactive functional group-containing compound. It is obtained by introducing an alkyl group, an alkenyl group or an aryl group and a polymerization reactive functional group into a main chain terminal active hydrogen group by reacting, and usually has an average molecular weight of 500
It is preferably at most 00.

Examples of the active hydrogen-containing compound include, for example, polyhydric alcohols such as methanol, ethanol, ethylene glycol, propylene glycol, 1,4-butanediol, glycerin, trimethylolpropane, sorbitol, sucrose, and polyglycerin; -Amine compounds such as ethylhexylamine, ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, aniline, benzylamine, phenylenediamine, bisphenol A,
Examples thereof include phenolic active hydrogen compounds such as hydroquinone and novolak, and compounds having different types of active hydrogen-containing groups in one molecule such as monoethanolamine and diethanolamine. Among them, polyhydric alcohols are particularly preferable.

Next, examples of the glycidyl ethers to be reacted with the active hydrogen-containing compound include alkyl-, alkenyl-, aryl- or alkylaryl-polyethylene glycol glycidyl ethers represented by the following formula.

[0012]

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Wherein n is an integer of 0 to 25, and R is an alkyl, alkenyl, aryl or alkylaryl group having 1 to 20 carbon atoms. As a typical one,
R is, for example, a linear alkyl group such as a methyl group, an ethyl group or a butyl group; a branched alkyl group such as an isopropyl group, a sec-butyl group or a tert-butyl group; a vinyl group; an allyl group;
Examples thereof include an alkenyl group such as a propenyl group and a 1,3-butadienyl group, and an aryl or alkylaryl group such as a phenyl group, a nonylphenyl group, a tolyl group, and a benzyl group. Among them, n is 1 to 15, and R has 1 to 1 carbon atom.
Twelve are preferred.

The alkylene oxides include ethylene oxide, propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, and 1,2-epoxyoctane. , 1,2-epoxynonane and the like having 4 to 4 carbon atoms
9, α-olefin oxides having 10 or more carbon atoms, styrene oxides, etc., among which ethylene oxide and propylene oxide are preferred.

The terminal group Y of the organic compound of the formula of the present invention is
One part is an alkyl group, an alkenyl group, or an aryl group, and the other part is a polymerization reactive functional group. Of the alkyl, alkenyl, and aryl groups, an alkyl group is particularly preferable, and a lower alkyl group, that is, a methyl group, an ethyl group, and the like are more preferable. These proportions are preferably 50 to 98% with respect to the terminal group Y. Examples of the polymerization reactive functional group include an acryloyl group, a methacryloyl group, and an allyl group, and an acryloyl group or a methacryloyl group is preferable. The ratio of the polymerization reactive functional group is 2 to 5 with respect to the terminal group Y.
0% is preferred. This means that the polymerization reactive functional groups are 2%
If the amount is less, the mechanical strength of the obtained ion-conductive polymer is low, while if it is more than 50%, a high ionic conductivity cannot be obtained.

As a method for introducing these groups to the terminal group Y, for example, a part of the terminal hydroxyl groups existing after the polymerization of the above-mentioned glycidyl ethers and alkylene oxides can be converted to an alkoxyl group by using an alkyl halide or the like. After the conversion, a method of further substituting the remaining hydroxyl groups by esterification or the like can be employed.

After doping the organic compound thus obtained with a soluble electrolyte salt compound exemplified below, a polymerization initiator or a sensitizer may be used, if necessary, to increase the activity of light, heat, electron beams or the like. The ion conductive polymer electrolyte of the present invention can be obtained by crosslinking under irradiation. As the soluble electrolyte salt compound, for example, lithium fluoride, lithium chloride, lithium bromide, lithium iodide, lithium nitrate, lithium thiocyanate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium tetrafluorofluoride, bistrifluoro Lithium methylsulfonylimide,
Lithium tristrifluoromethylsulfonylmethide, sodium thiocyanate, sodium perchlorate, sodium trifluoromethanesulfonate, sodium tetrafluorofluoride, potassium thiocyanate, potassium perchlorate, potassium trifluoromethanesulfonate, potassium tetrafluorofluoride And at least one or more selected from the group consisting of magnesium thiocyanate, magnesium perchlorate and magnesium trifluoromethanesulfonate.

[0018]

The ion-conductive polymer electrolyte of the present invention is composed of an organic polymer obtained by cross-linking a polyether compound having a specific structure having a side chain similar to the main chain, thereby stabilizing an amorphous phase contributing to ion conduction. It exhibits high ionic conductivity from low to high temperatures. In addition, since the main chain terminal group contains an appropriate amount of the polymerization reactive functional group, a certain mechanical strength can be maintained without lowering the ionic conductivity.

[0019]

Embodiments of the present invention will be described below. (Example 1) 18 g of glycerin and 730 g of methyldiethylene glycol glycidyl ether represented by the following formula
And 182 g of ethylene oxide were reacted in the presence of a catalyst (2 g of potassium hydroxide) and subjected to desalting and purification to obtain 876 g of a polyether having a molecular weight of 4700 (calculated from a hydroxyl value).

[0020]

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Then, 0.72 equivalents of sodium methylate with respect to the number of hydroxyl groups were added to the polyether, methanol was removed at 100 ° C. to alcoholate terminal hydroxyl groups, and then methyl iodide was added. For 6 hours to methoxylate 70% of the terminal hydroxyl groups. Then, by reacting 1.1 equivalents of acrylic acid with respect to the remaining number of hydroxyl groups, 20 times (by weight) of the acrylic acid, toluene and sulfuric acid 0.01 mol% at 80 to 90 ° C. for 8 hours to obtain a terminal. 70% of the groups are methoxylated to give 30
% Acrylated polyether was obtained. To 3.6 g of the terminal-modified polyether thus obtained, 0.4 g of lithium perchlorate and 0.02 g of a polymerization initiator (1-hydroxycyclohexyl phenyl ketone) were added, and the mixture was uniformly dissolved. Downflow, 7mw in nitrogen atmosphere
By irradiating ultraviolet rays at an intensity of / cm ² for 2 minutes, an ion-conductive polymer electrolyte having a thickness of 50 μm was obtained.

(Example 2) A mixture of 18 g of glycerin, 730 g of methyldiethylene glycol glycidyl ether represented by the following formula, and 182 g of ethylene oxide was reacted in the presence of a catalyst (2 g of potassium hydroxide).
After desalting and purification, 876 g of a polyether having a molecular weight of 4700 (calculated from the hydroxyl value) was obtained.

[0023]

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To this polyether was added 0.91 equivalent of sodium methylate based on the number of hydroxyl groups, methanol was removed at 100 ° C. to alcoholate the terminal hydroxyl groups, and methyl iodide was added. For 6 hours to methoxylate 90% of the terminal hydroxyl groups. Then, by reacting 1.1 equivalents of acrylic acid with respect to the remaining number of hydroxyl groups, 20 times (by weight) of the acrylic acid, toluene and sulfuric acid 0.01 mol% at 80 to 90 ° C. for 8 hours to obtain a terminal. 90% of the groups are methoxylated and 10
% Acrylated polyether was obtained. To 3.6 g of the terminal-modified polyether thus obtained, 0.4 g of lithium perchlorate and 0.02 g of a polymerization initiator (1-hydroxycyclohexyl phenyl ketone) were added, and the mixture was uniformly dissolved. Downflow, 7mw in nitrogen atmosphere
By irradiating ultraviolet rays at an intensity of / cm ² for 2 minutes, an ion-conductive polymer electrolyte having a thickness of 50 μm was obtained.

Example 3 A mixture of 20 g of sorbitol, 1320 g of methyltriethylene glycol glycidyl ether represented by the following formula, and 30 g of ethylene oxide was reacted in the presence of a catalyst (2.7 g of potassium hydroxide) to remove salts. Purification was performed to obtain 1251 g of a polyether (compound represented by the above formula) having a molecular weight of 12310 (calculated from a hydroxyl value). Here, R ¹ in the formula is a group represented by the above formula, and the symbols Z, p, m, Y,
The meanings of k, n and R are as shown in the following formula.

[0026]

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[0027]

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Then, 0.82 equivalents of sodium methylate with respect to the number of hydroxyl groups was added to the polyether, methanol was removed at 100 ° C. to alcoholate the terminal hydroxyl groups, and methyl iodide was added. For 6 hours to methoxylate 80% of the terminal hydroxyl groups. Then, by reacting 1.1 equivalents of acrylic acid with respect to the remaining number of hydroxyl groups, 20 times (by weight) of the acrylic acid, toluene and sulfuric acid 0.01 mol% at 80 to 90 ° C. for 8 hours to obtain a terminal. 80% of the groups are methoxylated to give 20
% Acrylated polyether was obtained. To 3.6 g of the terminal-modified polyether thus obtained, 0.4 g of lithium perchlorate and 0.02 g of a polymerization initiator (1-hydroxycyclohexyl phenyl ketone) were added, and the mixture was uniformly dissolved. Downflow, 7mw in nitrogen atmosphere
By irradiating ultraviolet rays at an intensity of / cm ² for 2 minutes, an ion-conductive polymer electrolyte having a thickness of 50 μm was obtained.

Example 4 20 g of ethylenediamine, 5520 g of phenylhexaethylene glycol glycidyl ether represented by the following formula, and ethylene oxide 117
The mixture with 3 g was reacted in the presence of a catalyst (9.4 g of potassium hydroxide) and subjected to desalination purification to give a molecular weight of 1992.
0590 g (calculated from the hydroxyl value) of polyether was obtained.

[0030]

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Then, 0.85 equivalent of sodium methylate was added to the polyether based on the number of hydroxyl groups, methanol was removed at 100 ° C. to alcoholate terminal hydroxyl groups, and methyl iodide was added. For 6 hours to methoxylate 85% of the terminal hydroxyl groups. Then, by reacting 1.1 equivalents of acrylic acid with respect to the remaining number of hydroxyl groups, 20 times (by weight) of the acrylic acid, toluene and sulfuric acid 0.01 mol% at 80 to 90 ° C. for 8 hours to obtain a terminal. 85% of the groups are methoxylated to give 15
% Acrylated polyether was obtained. To 3.6 g of the terminal-modified polyether thus obtained, 0.4 g of lithium perchlorate and 0.02 g of a polymerization initiator (1-hydroxycyclohexyl phenyl ketone) were added, and the mixture was uniformly dissolved. Downflow, 7mw in nitrogen atmosphere
By irradiating ultraviolet rays at an intensity of / cm ² for 2 minutes, an ion-conductive polymer electrolyte having a thickness of 50 μm was obtained.

Example 5 Pentaethylenehexamine 3
0 g, 480 g of methyltriethylene glycol glycidyl ether represented by the following formula, and ethylene oxide 46
0 g of the mixture was reacted in the presence of a catalyst (6.9 g of potassium hydroxide), desalted and purified to give a molecular weight of 7250.
850 g of a polyether (calculated from the hydroxyl value) (compound represented by the above formula) was obtained. Here, R ¹ in the formula is a group represented by the above formula, and the symbols Z, p,
The meanings of m, Y, k, n and R are as shown in the following formula.

[0033]

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[0034]

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To this polyether was added 0.51 equivalent of sodium methylate based on the number of hydroxyl groups, methanol was removed at 100 ° C. to alcoholate terminal hydroxyl groups, and methyl iodide was added. For 6 hours to methoxylate 50% of the terminal hydroxyl groups. Then, by reacting 1.1 equivalents of acrylic acid with respect to the remaining number of hydroxyl groups, 20 times (by weight) of the acrylic acid, toluene and sulfuric acid 0.01 mol% at 80 to 90 ° C. for 8 hours to obtain a terminal. 50% of the groups are methoxylated to give 50
% Acrylated polyether was obtained. To 3.6 g of the terminal-modified polyether thus obtained, 0.4 g of lithium perchlorate and 0.02 g of a polymerization initiator (1-hydroxycyclohexyl phenyl ketone) were added, and the mixture was uniformly dissolved. Downflow, 7mw in nitrogen atmosphere
By irradiating ultraviolet rays at an intensity of / cm ² for 2 minutes, an ion-conductive polymer electrolyte having a thickness of 50 μm was obtained.

Comparative Example In place of polyether having a molecular weight of 4700, ethylene oxide: propylene oxide =
An ion-conductive polymer electrolyte was obtained in the same manner as in Example 1 except that a random ether having an average molecular weight of 3000 was used at 8: 2 to produce a polyether whose terminal was completely acrylated.

(Lithium ion conductivity test) Next, in order to measure the ion conductivity of the ion-conductive polymer electrolytes of Examples 1 to 5 and Comparative Example thus obtained, each polymer electrolyte was plated with a platinum plate. The AC impedance between the electrodes was measured, and a complex impedance analysis was performed. The results are shown in Table 1 below. In addition, 100
Table 1 also shows the ionic conductivity after storage at 100 ° C for 100 days. The measuring instrument used was an impedance analyzer (model: 4192) manufactured by Yokogawa Hewlett-Packard Company.
A) was used, and the measurement conditions were as follows: applied voltage = 10
mV, measurement use frequency = 5 Hz to 13 MHz.

[0038]

[Table 1]

As is evident from Table 1, the ion-conductive polymer electrolyte of the present invention exhibits excellent ionic conductivity, particularly at relatively high temperatures.

[0040]

The ionic conductive polymer electrolyte according to the present invention exhibits high ionic conductivity stably from low to high temperatures. In addition, since it is a crosslinked polymer electrolyte, it does not have the fluidity found in conventional thermoplastic polymer electrolytes and can be used safely even at high temperatures.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01B 1/06 H01M 6/18 H01M 10/40

Claims (2)

(57) [Claims] 1. An average molecular weight of 1000 represented by the general formula
An ion-conductive polymer electrolyte comprising a soluble electrolyte salt compound in an organic polymer obtained by crosslinking an organic compound of up to 20,000. Embedded image Wherein Z is an active hydrogen-containing compound residue, R ¹ is a group represented by the following general formula (n is an integer of 0 to 25, R is an alkyl group, alkenyl group or aryl group having 1 to 20 carbon atoms); ² is a hydrogen or methyl group, terminal group Y is 1 carbon atom
To 20 alkyl groups, alkenyl groups or aryl groups and a polymerization reactive functional group;
The ratio of the phenyl group or the aryl group is 50 to 98%;
Wherein the ratio of the polymerization reactive functional groups is 2 to 50%, k is an integer of 1 to 12, p is an integer of 1 to 220, and m is 1 to 24.
Indicates an integer of 0. Embedded image 2. The ion conductive polymer electrolyte according to claim 1, wherein the polymerization reactive functional group constituting the terminal group Y is an acryloyl group, a methacryloyl group or an allyl group.