JP2000322931A - High molecular solid electrolyte - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the electrolyte that is composed of material capable of being polymerized at a temperature at which electrolyte salt is not decomposed, has high ion conductivity, and is stable chemically, by composing the electrolyte of a polymer formed by polymerizing poly (diethyleneglycolcarbonate) diacrylic acid ester and salt of metal of Ia-th group in the periodic table. SOLUTION: This high molecular solid electrolyte is composed of a polymer formed by polymerizing poly (diethyleneglycolcarbonate) diacrylic acid ester and salt of metal of Ia-th group in the periodic table. In the formula, n is 1 to 1000. preferably an integer of 5 to 500. Ester represented by the formula, an ester of poly (diethyleneglycolcarbonate) and acrylic acid, the poly (diethyleneglycolcarbonate) is composed by reacting diethyleneglycol, diester carbonate, and phosgene or carbonyl component such as chloroformate in a predetermined method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid polymer electrolyte used for primary batteries, secondary batteries, capacitors and the like.

[0002]

BACKGROUND OF THE INVENTION Conventionally, primary batteries, secondary batteries,
Liquid electrolytes, that is, electrolytes, have been used for electrochemical devices such as capacitors. However, there is a problem that the liquid electrolyte leaks or lacks long-term reliability.

As a method for solving such a problem, a method using a solid electrolyte is known, and when a solid electrolyte is used, a highly reliable element is provided without liquid leakage. In addition, the size and weight of the element itself can be reduced.

In recent years, various polymer solid electrolytes have been studied as such solid electrolytes. In addition, the polymer solid electrolyte has the characteristics of a solid electrolyte and has flexibility, so that it can be flexibly applied to a volume change occurring in an ion-electron exchange reaction process between an electrode and a polymer solid electrolyte. It is expected to be an electrolyte for electrochemical devices.

[0005] As such a solid polymer electrolyte, Japanese Patent Application Laid-Open No. 1-241764 discloses a crosslinked polymer obtained by polymerizing a methacrylic acid ester with a monomer having an ethylene oxide or propylene oxide chain, a polar polymer, and a polar polymer. A solid electrolyte comprising an aprotic liquid and an alkali metal is described. This Japanese Patent Application Laid-Open No. 1-24
No. 1764 describes as an example an example in which poly (diethylene glycol carbonate) dimethacrylate represented by the following formula (2) is used as a methacrylate.

[0006]

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However, methacrylic acid esters generally have a low polymerization rate. For example, when thermal polymerization is carried out by adding a polymerization initiator, it is necessary to carry out the polymerization at a relatively high temperature. At this time, if the polymerization is performed in a state where the electrolyte salt is dissolved, there is a problem that the salt is likely to be decomposed by heat.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polymer solid electrolyte which is formed from a material which can be polymerized at a temperature which does not decompose an electrolyte salt, has high ionic conductivity, and is chemically stable. I have.

[0009]

SUMMARY OF THE INVENTION The present inventor has made intensive studies to solve the above-mentioned problems of the prior art, and as a result, used poly (diethylene glycol carbonate) diacrylate ester having high polymerizability, By polymerizing the electrolyte salt and the electrolyte salt at a temperature at which the electrolyte salt does not decompose, it is found that a polymer solid electrolyte having high ionic conductivity and being chemically stable can be obtained.
The present invention has been completed.

That is, the present invention provides a poly (diethylene glycol carbonate) represented by the following general formula (1):
A polymer obtained by polymerizing diacrylate,

[0011]

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And a salt of a metal of Group Ia of the periodic table.

[Detailed Description of the Invention] Hereinafter, the polymer electrolyte according to the present invention will be specifically described. In the present specification, the term "polymerization" may be used in a sense that encompasses not only homopolymerization but also copolymerization, and the term "polymer" is used not only for homopolymers but also for copolymers. Is sometimes used in a sense that also includes

The polymer solid electrolyte according to the present invention comprises a polymer obtained by polymerizing poly (diethylene glycol carbonate) diacrylate represented by the general formula (1):

[0015]

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In the formula, n is from 1 to 1,000, preferably from 5 to
It is an integer of 500. And a salt of a metal of Group Ia of the periodic table. Poly (diethylene glycol carbonate) diacryl
Polymer of acid ester Poly (diethylene glycol carbonate) diacrylate represented by formula (1) is an ester of poly (diethylene glycol carbonate) and acrylic acid, and poly (diethylene glycol carbonate) is diethylene glycol and carbonate diester, phosgene. Or a carbonyl component such as chloroformate by a well-known method.

Specific examples of the carbonyl component include diester carbonates such as dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, dibutyl carbonate, diphenyl carbonate, ethylene carbonate and propylene carbonate, methyl chloroformate, ethyl chloroformate and phenyl chloroformate. Examples include chloroformate and phosgene.

The charging ratio of the carbonyl component to diethylene glycol is as follows.
It is preferably 0.5 to 2 moles with respect to the moles.
The number average molecular weight of such poly (diethylene glycol carbonate) determined by GPC analysis is 200 to 10
0000, preferably 1,000 to 50,000.

The poly (diethylene glycol carbonate) acrylate used in the present invention can be produced by a well-known esterification reaction, and specific examples thereof include the following methods.

A method in which poly (diethylene glycol carbonate) and acrylic acid halide are condensed in the presence of a base. In this method, acrylic acid halide is added to the hydroxyl group of poly (diethylene glycol carbonate) in an amount of 0.5 to 1
It is desirable to charge so as to be 0 equivalent.

Examples of the base used in the reaction include organic bases such as triethylamine, pyridine, dimethylaminopyridine and diazabicycloundecene (DBU); and inorganic bases such as sodium carbonate, potassium carbonate, sodium hydroxide and potassium hydroxide. Can be mentioned. Such a base is generally used in an amount of 1 to 5 equivalents per 1 mol of the acrylic acid halide. The reaction at this time is
It is also possible to carry out without solvent, but a solvent inert to the reaction, for example, a halogenated hydrocarbon such as dichloromethane, chloroform, dichloroethane, an aromatic hydrocarbon such as benzene, toluene, xylene, hexane, heptane, decane, The reaction may be performed in the presence of an aliphatic hydrocarbon such as cyclohexane, or an ether such as diethyl ether or tetrahydrofuran (THF). The reaction temperature is usually -20 to 100C, preferably -5 to 50C.
Is desirably within the range.

A method in which poly (diethylene glycol carbonate) and acrylic anhydride are condensed in the presence of a catalyst. In this method, acrylic anhydride is added to hydroxyl groups of poly (diethylene glycol carbonate) in an amount of from 0.2 to 5%.
It is desirable that the raw materials are charged so as to be equivalent, preferably 0.5 to 2 equivalent. Examples of the catalyst used for the reaction include sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, pyridine, and dimethylaminopyridine. Such a catalyst is generally used in an amount of 0.01 to 0.5 equivalent based on acrylic anhydride. This reaction can be performed in the presence of a solvent as described above.

The reaction temperature is usually in the range of -5 to 120 ° C, preferably 25 to 100 ° C. A method in which poly (diethylene glycol carbonate) and acrylic acid are condensed in the presence of an acid catalyst.

In this method, acrylic acid is added to the hydroxyl group of poly (diethylene glycol carbonate) in an amount of 0.1%.
It is desirable to charge so as to be 2 to 10 equivalents, preferably 1 to 5 equivalents. Examples of the acid catalyst used in the reaction include sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, and the like. Such acid catalysts are usually
It is used in an amount of 0.01 to 0.5 equivalent based on acrylic acid. This reaction is preferably performed in the presence of a solvent capable of azeotropic dehydration since water is generated at equilibrium.

The reaction temperature is usually in the range of 25 to 180 ° C., preferably 50 to 150 ° C. In producing poly (diethylene glycol carbonate) diacrylate as described above, a polymerization inhibitor may be used.

Examples of the polymer obtained by polymerizing the poly (diethylene glycol carbonate) diacrylate include (i) the homopolymer of the poly (diethylene glycol carbonate) diacrylate, and (ii) the poly (diethylene glycol carbonate). (Iii) a copolymer of the poly (diethylene glycol carbonate) diacrylate and another monomer copolymerizable with the poly (diethylene glycol carbonate) diacrylate, and the like. Is mentioned.

Other monomers copolymerizable with the poly (diethylene glycol carbonate) diacrylate include vinyl monomers, vinylidene monomers, and vinylene monomers. As such other monomers, vinyl esters, vinyl ethers, (meth) acrylates, allyl ethers, and allyl esters are preferable, and specifically, ethyl (meth) acrylate, ethoxyethyl (meth) acrylate, (meth) acrylate ) Ethoxyethoxyethyl acrylate, polyethylene glycol (meth) acrylate, allyl alcohol, vinyl acetate, styrene, α-methylstyrene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, acrylonitrile, vinyl cyanoacetate, allylamine, isopropyl Acrylamide, vinylene carbonate, maleic anhydride and the like can be mentioned.

Such other monomers are usually present in the polycarbonate (meth) acrylate polymer in an amount of from 0.1 to 90%.
% By weight, preferably 1 to 50% by weight.

Metal salts of Group Ia of the periodic table Metal salts of Group Ia of the periodic table include LiClO ₄ and LiB.
F ₄ , LiPF ₆ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (C
One or more Li salts selected from F ₃ SO ₂ ) ₂ and LiC (CF ₃ SO ₂ ) ₃ are preferred.

Polymer Solid Electrolyte The polymer solid electrolyte according to the present invention comprises the above-mentioned polymer of poly (diethylene glycol carbonate) diacrylate and a metal salt of Group Ia of the periodic table.

Such a solid polymer electrolyte can be prepared by using the poly (diethylene glycol carbonate) diacrylate alone or in the presence of another monomer copolymerizable with the poly (diethylene glycol carbonate) diacrylate in the periodic table. It is preferable to produce by integrally polymerizing with a metal salt of Group Ia.

The polymerization is carried out by coating on a flat substrate in the presence of at least one kind of poly (diethylene glycol carbonate) diacrylic acid and a metal salt of Group Ia of the periodic table, and irradiating with ultraviolet light, radiation or heat. .

In the case of polymerization by heat, a thermal polymerization initiator can be used, and depending on the polymerization mode, peroxides such as benzoyl peroxide and peroxydicarbonate, 2,
Azo compounds such as 2-azobisisobutyronitrile, nucleophiles such as alkali metals, and electrophiles such as Lewis acids can be used alone or in combination. The polymerization temperature at this time is 0
The reaction is carried out at a temperature of from 100 to 100 ° C, preferably from 20 to 90 ° C, at which the electrolyte salt does not decompose.

In the case of polymerization by irradiation with ultraviolet rays, a photosensitizer can be used. Examples of such a photosensitizer include benzophenone, acetophenone, and 2,2-dimethoxy-2-phenylacetophenone. Can be illustrated.

Further, the solid polymer electrolyte according to the present invention comprises:
In addition to the poly (diethylene glycol carbonate) diacrylate polymer and the metal salt of Group Ia of the periodic table, a non-aqueous solvent such as a carbonate ester is added to 100 parts by weight of the poly (diethylene glycol carbonate) diacrylate polymer. Preferably 0 to 1000 parts by weight,
Particularly preferably, it may be contained in an amount of 100 to 700 parts by weight. As a method for containing a non-aqueous solvent, for example, when producing a solid polymer electrolyte, polymerization may be carried out in the presence of a non-aqueous solvent, or the non-aqueous solvent may be impregnated after the polymerization. Carbonic acid esters or lactones are preferably used as the non-aqueous solvent. Examples of the carbonate include ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, and dipropyl carbonate. Examples of the lactone include γ-butyl lactone, δ-valerolactone, ε-caprolactone and the like.

The solid polymer electrolyte according to the present invention has high ionic conductivity and is electrochemically stable. Such a polymer solid electrolyte can be used for, for example, primary batteries, secondary batteries, capacitors, electrochemical devices such as electrochromic display devices, medical actuators, and the like.

Further, the solid polymer electrolyte according to the present invention comprises:
It can be used as an alternative to an organic electrolyte for a lithium ion secondary battery. Furthermore, it can also be used as a binder used for dispersing and fixing the powdered electrode material into a current collector.

When such a solid polymer electrolyte is used in a battery, the battery can be manufactured by forming the solid polymer electrolyte into a film in advance and sandwiching it between a positive electrode and a negative electrode.

In a battery manufacturing process having a step of forming a three-layer structure of a positive electrode, a separator, and a negative electrode and then impregnating with an electrolyte, a poly (diethylene glycol carbonate) diacrylate and a periodic table are used instead of the electrolyte. It is also possible to impregnate a solution consisting of a Group Ia metal salt and a non-aqueous solvent and then polymerize it, minimizing process modifications.

[0040]

According to the present invention as described above, since an acrylic acid ester is used, the polymerization rate is high and the polymerization can be carried out even at a relatively low temperature. Therefore, even when the polymerization is performed in a state where the electrolyte salt is dissolved, the salt is not decomposed by heat.

Therefore, according to the present invention, a polymer solid electrolyte which is formed from a material which can be polymerized at a temperature which does not decompose the electrolyte salt, has high ionic conductivity, and is chemically stable can be obtained. Such a polymer solid electrolyte,
It can be used for primary batteries, secondary batteries, capacitors, electrochemical devices such as electrochromic display devices, and medical actuators.

[0042]

EXAMPLES The present invention will now be described with reference to specific examples, but the present invention is not limited to these examples.

[0043]

Synthesis Example 1 26.5 g of diethylene glycol was placed in a glass reaction vessel equipped with a stirrer, a thermometer, a rectification tower, and the like.
Mix 22.5 g of dimethyl carbonate and 0.095 g of a 28% sodium methoxide methanol solution as a catalyst,
Hold at 95 ° C under normal pressure for 2 hours, then 155 ° C for 5 hours
And further heated at 155 ° C. for 4 hours. At this time, methanol generated by the reaction was distilled off.

Then, under reduced pressure of 5 mmHg,
While maintaining the temperature at 155 ° C., 4.5 g of diethylene glycol produced during the polymerization reaction was distilled off. After cooling to room temperature, 50 ml of chloroform and 1 g of activated clay were added, and the mixture was added at 55 ° C for 1 hour.
Stirred for hours. After cooling to room temperature, the activated clay was filtered and the filtrate was concentrated to obtain 25.4 g of poly (diethylene glycol carbonate) as a viscous oil. GP of the obtained poly (diethylene glycol carbonate)
The number average molecular weight of C was 1,400.

Next, 25.4 g of the obtained poly (diethylene glycol carbonate), 16.0 g of triethylamine and 100 ml of dichloromethane were mixed in a glass reaction vessel equipped with a stirrer, thermometer, dropping funnel and the like, and cooled to 5 ° C. Acrylic chloride (11.9 g) was added dropwise from the dropping funnel over 10 minutes, and the mixture was further stirred at 5 ° C. for 1 hour. The temperature was gradually raised to room temperature, and the mixture was further stirred at room temperature for 2 hours. The reaction solution was filtered, the filtrate was washed with saturated saline, dried over anhydrous magnesium sulfate, and concentrated to obtain 27.1 g of the target poly (diethylene glycol carbonate) diacrylate as a viscous oil. .

[0046]

[Synthesis Example 2] In Synthesis Example 1, 13.8 methacrylic acid chloride was used instead of acrylic acid chloride in the esterification reaction.
The reaction was carried out in the same manner except that g was used. 27.3 g of the target poly (diethylene glycol carbonate) dimethacrylate was obtained as a viscous oil.

[0047]

Example 1 22.2 parts by weight of poly (diethylene glycol carbonate) diacrylate produced in Synthesis Example 1, 66.5 parts by weight of propylene carbonate, LiP
F ₆ 11.3 parts by weight of 1, Peroyl IPP-50
(Manufactured by Nippon Oil & Fats Co., Ltd.)
The solution made uniform by adding mol% is placed in an inert gas atmosphere.
Cast on a glass plate and place on a hot plate at 70 ° C.
The mixture was cured by heating for 5 minutes to obtain a solid polymer electrolyte having a thickness of about 0.5 mm as a free-standing film.

This polymer electrolyte was punched out into a 10 mmφ disk shape, sandwiched between electrodes provided on a conductivity measuring holder, and controlled at 25 ° C. with a Peltier device to control the impedance of the polymer electrolyte (HP4285A).
Was used to measure the complex impedance (measurement voltage: 10 mV), and the ionic conductivity was determined analytically. The ionic conductivity was 2.1 × 10 ⁻³ S / cm.

[0049]

[Comparative Example 1] Poly (diethylene glycol carbonate) prepared in Synthesis Example 2 dimethacrylate 25 parts by weight, equal volume mixture of ethylene carbonate and propylene carbonate in a LiPF ₆ (weight ratio) at a concentration of 1 mol / l electrolyte Mix 75 parts by weight of the liquid
A solution made uniform by adding 2 mol% of PP-50 to the content of the polymerizable double bond was cast on a glass plate in an inert gas atmosphere, and cured by heating at 70 ° C. for 15 minutes on a hot plate. However, the strength was insufficient and a free-standing membrane as a polymer solid electrolyte could not be obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01M 6/18 H01M 10/40 B 5H024 10/40 C08F 20/28 5H029 // C08F 20/28 290/06 290/06 C08G 63/64 C08G 63/64 H01G 9/02 331Z (72) Inventor Masaharu Shindo 3-5-2 Kasumigaseki, Chiyoda-ku, Tokyo F-term in Mitsui Chemicals, Inc. 4J002 BG071 CG011 DD036 DE196 DH006 DK006 EV256 GQ00 4J027 AC03 AH03 BA04 BA05 BA07 CA14 CD00 4J029 AA09 AB01 AD01 BF09 HC01 HC04A HC09 KH01 4J100 AL66P BA02P BA22P CA01 JA45 5G301 CA16 CA17 CA30 CD01 5H024 FF22 FF31 FF36 5H012 AJ02A02

Claims (1)

[Claims] 1. A polymer obtained by polymerizing a poly (diethylene glycol carbonate) diacrylate represented by the following general formula (1): A solid polymer electrolyte comprising a salt of a metal of Group Ia of the Periodic Table.