JP2015205849A - Novel oxetane compound and polymer thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer having high conductivity and usable as a solid electrolyte for a secondary battery, and a monomer as a raw material of the polymer.SOLUTION: There are provided an oxetane compound represented by the formula (1) and a solid electrolyte containing a polymer obtained by polymerizing the compound. (1), where Ris a C1 to 6 alkyl group, Ris a C1 to 4 alkylene group, Rto Rare each independently H, a C1 to 10 alkyl group or a group having a nitrile group in a terminal represented by the formula (2), where Ris a C1 to 10 alkylene group which may contain one or more group selected from ether (-O-), sulfide (-S-) and amine (-NH-) and wavy line is a covalent bond to a carbon atom, provided that at least one of Rto Ris a group having a nitrile group in the terminal represented by the formula (2).

Description

  The present invention relates to a novel oxetane compound and a polymer thereof, and to a solid electrolyte containing the polymer.

  Lithium ion batteries are used as a power source for small electronic devices such as mobile phones and notebook computers, and are indispensable for modern society. Usually, a lithium ion battery includes a flammable organic solvent such as propylene carbonate or ethylene carbonate as an electrolyte. In recent years, lithium-ion batteries have come to be used as power sources for electric vehicles and large-sized secondary batteries for home use. There is a need for further improvements in sex.

  As a means for solving the safety problem, the use of a solid electrolyte containing no solvent in the electrolyte, that is, an intrinsic polymer electrolyte, for a lithium ion battery has attracted attention. The intrinsic polymer electrolyte is composed of a metal salt and a polymer, and has an advantage that the shape of the battery can be freely designed in addition to containing no solvent.

  However, intrinsic polymer electrolytes have problems such as low ionic conductivity and low flexibility compared with liquid electrolytes and poor adhesion to electrodes.

The inventors of the present invention have studied to solve the above problem, and have so far had a trimethylene oxide structure (—CH ₂ CH ₂ CH ₂ O—) as a polymer repeating structure, and a nitrile at the end of the side chain. A polymer having a group having a group is disclosed (Patent Documents 1, 2, and 3). It was found that the electrolyte containing the polymer was given flexibility by the trimethylene oxide structure, and the lithium salt was dissociated by the nitrile group to show ionic conductivity.

  However, the types of polymers used as the material for the intrinsic polymer electrolyte are limited to those shown in Patent Documents 1 and 3, and a new polymer with flexibility and high conductivity that can be actually used in batteries is used. Furthermore, it has been a challenge to expand the range of selection of the polymer that is the heading and material.

JP 2008-277218 A JP 2013-043980 A JP 2013-043880 A

  It is an object of the present invention to provide a polymer having excellent ionic conductivity and high flexibility and a monomer as a raw material thereof.

As a result of intensive studies to solve the above problems, a novel polymer having a trimethylene oxide structure (—CH ₂ CH ₂ CH ₂ O—) obtained by polymerizing a specific oxetane compound as a repeating structure of the polymer has excellent ionic conductivity. And found that it is very flexible.

That is, the present invention provides (1) an oxetane compound represented by formula (1),
[Wherein, R ¹ represents a C1-C6 alkyl group. R ² represents a C1-C4 alkylene group. R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom, a C1-C10 alkyl group, or a group having a nitrile group at the terminal represented by the formula (2).
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). And the wavy line represents a covalent bond to a carbon atom. However, at least one of R ³ , R ⁴ and R ⁵ is a group having a nitrile group at the terminal represented by the formula (2). ]
(2) R ³ is a group having a nitrile group at the terminal represented by formula (2)
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). The wavy line represents a covalent bond to a carbon atom), and R ⁴ and R ⁵ are a hydrogen atom or a C1-C10 alkyl group,
(3) R ³ and R ⁴ are groups having a nitrile group at the terminal represented by the formula (2)
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). And the wavy line represents a covalent bond to a carbon atom.), And R ⁵ is a hydrogen atom or a C1-C10 alkyl group,
(4) A group in which all of R ³ , R ⁴ and R ⁵ have a nitrile group at the terminal represented by the formula (2)
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). Wherein the wavy line represents a covalent bond to a carbon atom.)
(5) A group having a nitrile group at the terminal represented by the formula (2),
The compound according to any one of (1) to (4),
(6) R ¹ is an ethyl group, R ² is a methylene group, and a group having a nitrile group at the end represented by the formula (2)
The compound according to any one of (1) to (4),
(7) a polymer having a repeating unit represented by formula (3),

[Wherein, R ¹ represents a C1-C6 alkyl group. R ² represents a C1-C4 alkylene group. R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom, a C1-C10 alkyl group, or a group having a nitrile group at the terminal represented by the formula (2).
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). And the wavy line represents a covalent bond to a carbon atom. However, at least one of R ³ , R ⁴ and R ⁵ is a group having a nitrile group at the terminal represented by the formula (2). n represents the number of repeating units. ]
(8) R ³ is a group having a nitrile group at the terminal represented by the formula (2)
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). Wherein the wavy line represents a covalent bond to a carbon atom.), And R ⁴ and R ⁵ are a hydrogen atom or a C1-C10 alkyl group,
(9) R ³ and R ⁴ are groups having a nitrile group at the terminal represented by the formula (2)
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). Wherein the wavy line represents a covalent bond to a carbon atom.), And R ⁵ is a hydrogen atom or a C1-C10 alkyl group,
(10) A group in which all of R ³ , R ⁴ and R ⁵ have a nitrile group at the terminal represented by the formula (2)
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). Wherein the wavy line represents a covalent bond to a carbon atom.)
(11) A group having a nitrile group at the terminal represented by the formula (2)
The polymer according to any one of (7) to (10),
(12) R ¹ is an ethyl group, R ² is a methylene group, and a group having a nitrile group at the terminal represented by the formula (2)
The polymer according to any one of (7) to (10),
(13) A solid electrolyte comprising the polymer according to any one of (7) to (12),
(14) The solid electrolyte according to (13) above, which contains an ion carrier,
(15) The solid electrolyte according to (13) or (14) above, comprising a reinforcing material,
(16) A battery comprising the solid electrolyte according to any one of (13) to (15).

  Since the polymer of the present invention is excellent in ionic conductivity and rich in flexibility, it can be used as a material for an intrinsic polymer electrolyte for use in a battery. Because it does not contain a flammable solvent, it can be used for large batteries without worrying about liquid leakage or fire. Further, the intrinsic polymer electrolyte is solid, and the shape of the battery can be designed freely. In addition, the polymer of the present invention includes known 3-ethyl-3- (hydroxymethyl) oxetane described in Patent Document 1 and N- [2- (2-cyanoethoxy) -1,1- Since the degree of polymerization can be made larger than that of a polymer obtained by polymerizing bis [(2-cyanoethoxy) methyl] ethyl] -3-ethyl-3-oxetanamide, the strength can be further increased.

¹ CEES ¹ HNMR chart 1 CES ¹³ C NMR chart 1CEES FT-IR chart ¹ HNMR chart of 2CEES ¹³ CNMR chart of 2CEES 2CEES FT-IR Chart ¹ HNMR chart of 3CEES ¹³ CNMR chart of 3CEES 3CEES FT-IR Chart ¹ HNMR chart of P1CEES P1CEES FT-IR chart P1CEES GPC Chart ¹ HNMR chart of P2CEES P2CEES FT-IR chart P2CEES GPC Chart ¹ HNMR chart of P3CEES P3CEES FT-IR chart P3CEES GPC Chart Ionic conductivity at each Li / CN value of P1CEES Ionic conductivity at each Li / CN value of P2CEES Ionic conductivity at each Li / CN value of P3CEES

(Compound)
The compound of this invention is the following oxetane compounds represented by Formula (1).

In the formula, R ¹ represents a C1-C6 alkyl group. R ² represents a C1-C4 alkylene group. R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom, a C1-C10 alkyl group, or a group having a nitrile group at the terminal represented by the formula (2).
Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). And the wavy line represents a covalent bond to a carbon atom. However, at least one of R ³ , R ⁴ and R ⁵ is a group having a nitrile group at the terminal represented by the formula (2).

The C1-C6 alkyl group in R ¹ means a linear or branched alkyl group having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and an n-butyl group. , Isobutyl group, tert-butyl group, n-pentyl group, n-hexyl group and the like.

The C1-C4 alkylene group in R ² means a linear or branched alkylene group having 1 to 4 carbon atoms, such as a methylene group, an ethylene group, an n-propylene group, an isopropylene group, n -Represents a butylene group, an isobutylene group, a tert-butylene group or the like.

The C1-C10 alkyl group in R ³ , R ⁴ and R ⁵ means a linear or branched alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, or isopropyl. A group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, nonyl group, isononyl group, decyl group and the like.

The C1-C10 alkylene group which may contain one or more groups selected from the group consisting of the ether (—O—), sulfide (—S—) and amine (—NH—) in R ⁶ is A C1-C10 linear or branched alkylene group which may contain ether (-O-), sulfide (-S-), amine (-NH-), for example, methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group, isobutylene group, tert-butylene group, hexylene group, octylene group and dodecylene group, —CH ₂ —O—CH ₂ —, —CH ₂ —O— (CH _{2) 2 -, - (CH} 2) 2 -O- (CH 2) 2 -, - CH 2 -S- (CH 2) 2 -, - CH 2 -NH- (CH 2) 2 -, - (CH ₂ ) ₂ -S- (CH ₂ ) ₂ -,-(CH ₂ ) ₂ -NH- (CH ₂ ) _2- and the like.

  Specific examples of the compound represented by the formula (1) include the compounds shown in Table 1.

(Synthesis of compounds)
The method for synthesizing the compound represented by the formula (1) of the present invention is not particularly limited. For example, a 3-alkyl-3-oxetanic acid represented by the formula (4) and the formula (5) Examples include a method in which the alcohol represented is dehydrated and condensed in an appropriate reaction solvent as necessary in the presence or absence of a condensing agent and a catalyst.

(R ¹ , R ² , R ³ , R ⁴ , R ⁵ represent the same meaning as described above.)

  The condensing agent is not particularly limited as long as it is a condensing agent usually used in a dehydration condensation reaction. For example, N, N′-dicyclohexylcarbodiimide (DCC), 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride Salt (EDC), N, N′-diisopropylcarbodiimide (DIC), 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride (WSC), diphenylphosphoryl azide (DPPA), (benzotriazol-1-yl -Oxy) trisdimethylaminophosphonium hexafluorophosphate (BOP), (benzotriazol-1-yl-oxy) tripyrrolidinophosphonium hexafluorophosphate (PyBOP), (7-azabenzotriazol-1-yloxy) trispyrrolidinophospho D Muphosphate (PyAOP), bromotrispyrrolidinophosphonium hexafluorophosphate (BroP), chlorotris (pyrrolidin-1-yl) phosphonium hexafluorophosphate (PyCroP), 3- (diethoxyphosphoryloxy) -1,2,3- Benzotriazin-4 (3H) -one (DEPBT), O- (benzotriazol-1-yl) -N, N, N ′, N′-tetramethyluronium hexafluorophosphate (HATU), 4- (5 6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholine hydrochloride (DMTMM) and the like. Although the usage-amount of a condensing agent is not specifically limited, As an equivalent ratio with respect to 3-alkyl-3-oxetanic acid represented by Formula (4), it is the range of 1.0-10, Preferably it is the range of 1.0-3.0. Is appropriately selected.

  The catalyst is not particularly limited as long as it is usually used in a dehydration condensation reaction and has an action of activating carboxylic acid, and examples thereof include 4-dimethylaminopyridine (DMAP). Although the usage-amount of a catalyst is not specifically limited, As an equivalent ratio with respect to 3-alkyl-3- oxetanoic acid represented by Formula (4), it is 0.01-10, Preferably it is from the range of 0.05-1.0. It is selected appropriately.

  Examples of the solvent in the dehydration condensation include aromatic hydrocarbon solvents such as benzene and toluene, amide solvents such as acetonitrile, N, N-dimethylacetamide and N, N-dimethylformamide, and ethers such as tetrahydrofuran and diethyl ether. System solvents, halogen solvents such as dichloromethane, dichloroethane, and chloroform. These reaction solvents may be used alone or in appropriate combination of two or more. Although the usage-amount of a solvent is not specifically limited, The compound represented by Formula (4) is 0.01-2 (mol / L), Preferably it is a density | concentration of 0.05-1.0 (mol / L). The range is appropriately selected.

  The temperature during the dehydration condensation reaction is usually 0 to 200 ° C., preferably 20 to 130 ° C., and is appropriately selected depending on the solvent used. The reaction may be carried out in an air atmosphere, but usually it is preferably carried out in an inert gas atmosphere. Examples of the inert gas include argon, helium, and nitrogen gas.

  After concentrating the reaction solution after completion of the dehydration condensation reaction as necessary, the residue may be used as it is or after appropriate post-treatment, and then used as a compound represented by the formula (1). Specific methods for the post-treatment include known purification such as extraction, crystallization, recrystallization, chromatography and the like.

The 3-alkyl-3-oxetanoic acid represented by the above formula (4) is obtained by condensing the aldehyde (6) with formaldehyde, followed by Patolson's method (J. Am. Chem. Soc., 1957, 79). It is obtained by synthesizing alcohol (8) from (7) and then oxidizing it by a known method (Japanese Patent Laid-Open No. 2013-43880). As the alcohol (7), commercially available 3-methyl-3-oxetanemethanol, 3-ethyl-3-oxetanemethanol (ECO), or the like may be used.

(R ¹ represents the same meaning as described above.)

Alcohol (5)
R ³ is a group having a nitrile at the terminal represented by the formula (2)

(Wherein R ⁶ and the wavy line represent the same meaning as described above), and R ⁴ and R ⁵ are a hydrogen atom or a C1-C10 alkyl group (alcohol I);
When R ³ and R ⁴ are a group having a nitrile at the terminal represented by the formula (2), and R ⁵ is a hydrogen atom or a C1-C10 alkyl group (alcohol II);
When all of R ³ , R ⁴ and R ⁵ are groups having a nitrile at the terminal represented by the formula (2) (alcohol III)
There are three cases, and each is synthesized by the following method.

[Synthesis of Alcohol I]
A method (method A) of halogenating the diol represented by the formula (9) and then nitrifying with a cyanide compound such as potassium cyanide and sodium cyanide is not limited thereto.

(Method A)

(R ² and R ⁶ represent the same meaning as described above. R ⁴ and R ⁵ represent a hydrogen atom or a C1-C10 alkyl group, and X represents a halogen atom.)

In particular, a group having a nitrile at the terminal represented by formula (2) is represented by formula (2-1),

(R ⁶ ′ represents a C1-C8 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). The wavy line represents a covalent bond to a carbon atom.)
The alcohol I can be synthesized by reacting the diol represented by the formula (9-1) with commercially available acrylonitrile (Method B).

(Method B)

^{(R 6} ', ^{R 2} is, .R ⁴ and ^{R 5} as defined above represents a hydrogen atom or an alkyl group C1 -C10.)

  Examples of the diol represented by the formula (9) and the formula (9-1) include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5- Pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol, diethanolamine, N-methyldiethanolamine, N-methyl Examples include ethanolamine and 2-hydroxyethyl sulfide.

[Synthesis of Alcohol II]
Examples of the method include, but are not limited to, a method (Method C) in which the triol represented by the formula (11) is halogenated and then nitrified with a cyanide compound such as potassium cyanide and sodium cyanide.

(Method C)

(R ² , R ⁶ and X are as defined above. R ⁵ represents a hydrogen atom or a C1-C10 alkyl group.)

In particular, a group having a nitrile at the terminal represented by formula (2) is represented by formula (2-1),

(R ⁶ ', the wavy line represents the same meaning as described above.)
The alcohol II can be synthesized by reacting the triol represented by the formula (11-1) with commercially available acrylonitrile (Method D).

(Method D)

(R ² and R ⁶ ′ have the same meaning as described above. R ⁵ represents a hydrogen atom or a C1-C10 alkyl group.)

Examples of the triol represented by the formula (11) and the formula (11-1) include 1,1,1-tris (hydroxy) by a reaction between an aldehyde represented by the formula (13) and formaldehyde as shown below. It can be synthesized as a methyl) alkane. Commercially available 1,1,1-tris (hydroxymethyl) ethane, 1,1,1-tris (hydroxymethyl) propane and the like are used as the triols represented by the formulas (11) and (11-1). You can also.

(R ⁵ represents a hydrogen atom or a C1-C10 alkyl group.)

  Further, the triol represented by the formula (11) and the formula (11-1) can also be synthesized by carbonizing the 1,1,1-tris (hydroxymethyl) alkane by oxidation, Wittig reaction, or hydroboration. it can. Further, the 1,1,1-tris (hydroxymethyl) alkane and a primary hydroxyl group such as 2-bromoethanol and an alkane containing a primary halogen are subjected to a Williamson reaction to construct an ether bond, Triols represented by (11) and formula (11-1) can also be synthesized.

When R ⁶ and R ⁶ ′ are C1-C10 alkylene groups containing sulfide (—S—), first, the 1,1,1-tris (hydroxymethyl) alkane is converted into a hydroxyl group by a method such as an Appel reaction. After being halogenated, it is induced to thiol by a method of reacting with hydrogen sulfide in the presence of alkali or a method of reacting with thiourea. Next, sulfide (—S—) can be introduced into the C1-C10 alkylene group by nucleophilic substitution reaction of the alkane containing the primary hydroxyl group and the primary halogen.

When R ⁶ and R ⁶ ′ are a C1-C10 alkylene group containing an amine (—NH—), first, the 1,1,1-tris (hydroxymethyl) alkane is converted into a hydroxyl group by a method such as an Appel reaction. Is halogenated and then reacted with ammonia (NH ₃ ). Next, an amine (—NH—) can be introduced into the C1-C10 alkylene group by nucleophilic substitution reaction of the alkane containing the primary hydroxyl group and the primary halogen.

[Synthesis of Alcohol III]
Examples of the method include, but are not limited to, a method (Method E) in which the tetraol represented by the formula (13) is halogenated and then nitrified with a cyanide compound such as potassium cyanide and sodium cyanide.

(Method E)

(R ² , R ⁶ and X have the same meaning as described above.)

In particular, a group having a nitrile at the terminal represented by formula (2) is represented by formula (2-1),

(R ⁶ ', the wavy line represents the same meaning as described above.)
The alcohol III can be synthesized by reacting the tetraol represented by the formula (13-1) with commercially available acrylonitrile (Method F).

(Method F)

(R ⁶ 'and R ² represent the same meaning as described above.)

  Examples of the tetraol represented by the formula (13) and the formula (13-1) include pentaerythritol. Further, tetraols represented by the formula (13) and the formula (13-1) can also be synthesized by increasing the amount of carbon by oxidation, Wittig reaction, or hydroboration of pentaerythritol. Furthermore, the formula (13) and the formula (13-) can also be obtained by Williamson reaction of pentaerythritol with a primary hydroxyl group such as 2-bromoethanol and an alkane containing a primary halogen to construct an ether bond. The tetraol represented by 1) can be synthesized.

When R ⁶ and R ⁶ ′ are C1-C10 alkylene groups containing sulfide (—S—), first, tetraols represented by formula (13) and formula (13-1) are subjected to an Appel reaction, etc. After the hydroxyl group is halogenated by this method, it is induced to thiol by a method of reacting with hydrogen sulfide in the presence of an alkali or a method of reacting with thiourea. Next, sulfide (—S—) can be introduced into the C1-C10 alkylene group by nucleophilic substitution reaction of the alkane containing the primary hydroxyl group and the primary halogen.

When R ⁶ and R ⁶ ′ are a C1-C10 alkylene group containing an amine (—NH—), first, tetraols represented by the formula (13) and the formula (13-1) are subjected to an Appel reaction or the like. After the hydroxyl group is halogenated by this method, it is reacted with ammonia (NH ₃ ). Next, an amine (—NH—) can be introduced into the C1-C10 alkylene group by nucleophilic substitution reaction of the alkane containing the primary hydroxyl group and the primary halogen.

(polymer)
The polymer of the present invention is the following polymer represented by the formula (3) obtained by polymerizing the compound represented by the formula (1).

In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ represent the same meaning as described above. n represents the number of repeating units.

  As a method for obtaining the polymer represented by the formula (3), the compound represented by the formula (1) is oxetane ring in an appropriate reaction solvent as necessary in the presence or absence of a Lewis acid catalyst. Is a method of ring-opening polymerization.

The Lewis acid catalyst is not particularly limited as long as it has an action of coordinating and activating the oxygen atom of the oxetane ring. For example, zinc chloride, iron chloride, cobalt chloride, tin chloride, aluminum chloride, titanium chloride, etc. Metal halides, boron trifluoride compounds such as boron trifluoride-ethyl ether complex (BF ₃ .Et ₂ O), and triflate compounds such as yttrium triflate and hafnium triflate. Although the usage-amount of a catalyst is not specifically limited, As an equivalent ratio with respect to the compound represented by Formula (1), it is suitably selected from the range of 0.01-10, Preferably it is 0.1-5.0.

  Examples of the solvent include aromatic hydrocarbon solvents such as benzene and toluene, amide solvents such as acetonitrile, N, N-dimethylacetamide and N, N-dimethylformamide, ether solvents such as tetrahydrofuran and diethyl ether, Examples thereof include halogen solvents such as dichloromethane, dichloroethane, and chloroform. These reaction solvents may be used alone or in appropriate combination of two or more.

  The temperature during the polymerization reaction is usually −20 to 200 ° C., preferably 20 to 130 ° C., and is appropriately selected depending on the solvent used. The reaction may be carried out in an air atmosphere, but usually it is preferably carried out in an inert gas atmosphere. Examples of the inert gas include argon, helium, and nitrogen gas.

  If necessary, the polymerization reaction is stopped with a solvent such as ethanol, the reaction solution after completion is concentrated as necessary, the residue is left as it is or after appropriate post-treatment, It can be used as a polymer represented by (3). Specific methods for the post-treatment include known purification such as extraction, crystallization, reprecipitation, and chromatography.

  N which is the number of repeating units of the polymer of the present invention is 2 to 10,000, preferably 2 to 1,000. The polymer has a molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of 5 or less, preferably 3 or less.

(Electrolytes)
The electrolyte in the present invention contains the polymer represented by the formula (3) of the present invention and inorganic salts used as an ion carrier, and can be used alone as a solid electrolyte in a battery or the like. In order to enhance the maintenance force, other polymer substances may be mixed as a reinforcing material.

As the inorganic salts used as the ion carrier, monovalent or divalent metal salts used in conventional lithium batteries and the like can be used. For example, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , Li ₂ SiF ₆ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (CF ₃ CF ₂ SO ₂ ) ₂ N, LiB (C ₂ Lithium salts such as O ₂ ) ₂ , LiPF ₃ (CF ₃ CF ₂ ) ₃ , LiTFSA (lithium bistrifluoromethanesulfonylimide), magnesium salts such as Mg (ClO ₄ ) ₂ , Mg (CF ₃ SO ₃ ) _2, etc. However, it is not limited to these. Also preferred are LiPF ₆ , LiBF ₄ , and LiTFSA.

  The inorganic salt is generally mixed in the solid electrolyte in an amount of about 10 to 90% by mass with respect to the total mass of the solid electrolyte (not including the reinforcing material described later). Preferably, it is 50-80 mass%. If it is less than 10 mass%, it is inferior to electroconductivity and high load charge / discharge property. Moreover, it is difficult to mix a large amount of inorganic salts exceeding 100% by mass, and the whole becomes hard and brittle, resulting in poor moldability.

  Other polymer substances as the reinforcing material include vinylidene fluoride-hexafluoropropylene copolymer (abbreviated as PVDF-HFP), polyacrylonitrile, acrylate ester, or methacrylate polymer, acrylic acid, Alternatively, a polymer having a polar group such as a polymer of methacrylic acid, polyvinyl acetate, polyvinyl alcohol, or polyethylene oxide can be used, but PVDF-HFP is particularly preferable because of its durability.

  Other polymer substances as the reinforcing material can generally be mixed up to about 200% by mass with respect to the polymer of the present invention. If the mixing ratio of the reinforcing material is small, the strength at the time of formation is inferior, and if it is mixed in a large amount exceeding 200% by mass, the strength is improved, but the conductivity is lowered. Therefore, in general, the mixing ratio may be appropriately determined according to the purpose with about 50 to 100% by mass as a guide.

(battery)
The battery in the present invention is not limited as long as it contains the electrolyte of the present invention, and the structure thereof is not particularly limited, and a general battery, particularly a primary battery using a known solid electrolyte or The same structure as the secondary battery is adopted. For example, a positive electrode, a negative electrode, and a short-circuit prevention diaphragm are disposed between the positive electrode and the negative electrode as necessary, and a solid electrolyte is present between both electrodes.

The positive electrode is a material that can occlude and release ion carriers. Examples of the positive electrode include LixMO ₂ and LiyM ₂ O ₄ (where M is a transition metal, X is a number from 0 to 1, and y is a number from 0 to 2) as a positive electrode active material containing lithium. Specifically, LiCoO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LizMO ₂ (M represents Ni, Mn, Co, Al or Mg, Z represents a number of 0.9 to 1.2). . Examples of the positive electrode active material not containing lithium include S, MnO ₂ , FeO ₂ , FeS ₂ , V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , TiS ₂ , MoS ₂ , NbSe, or polyaniline, polythiophene, polyacetylene. Polypyrrole or the like can also be a positive electrode active material.
Among these, a lithium-containing compound is preferable because a high voltage and a high energy density can be obtained.

  The particle diameter of the positive electrode active material is generally 0.1 μm to 100 μm, preferably 1 μm to 10 μm.

  The positive electrode is generally applied to the positive electrode current collector by adding a conductive additive or a binder to the positive electrode active material to form a paste. In the present invention, since the polymer itself of the present invention has adhesiveness, the conductive auxiliary agent and the binder can be omitted, which is further advantageous.

  The positive electrode current collector is Al, Ni or stainless steel foil or nonwoven fabric.

  The negative electrode is an inorganic salt constituting metal serving as an ion carrier as a negative electrode active material, for example, a material that can occlude or release lithium ions, such as metallic lithium, or amorphous carbon, graphite, pyrolytic carbon, coke, glassy carbon, carbon Carbon, such as fiber, activated carbon, carbon black, or a fired body of phenol resin or furan resin can also be used. Furthermore, metal ions that serve as ion carriers, for example, alloys of lithium and other metals can also serve as the negative electrode active material. For example, alloys such as Ti, Sn, Pb, Al, In, Si, Zn, Sb, Bi, Ga, Ge, As, Ag, Hf, Zr, and Y can also be used. Among these, Ti, Si, Sn and the like are preferable alloy materials.

  The negative electrode active material has a particle size of 0.1 μm to 100 μm, preferably 1 μm to 10 μm.

  As with the positive electrode, a conductive additive and a binder are added to the negative electrode, and if necessary, dispersed in a solvent to form a base and applied to the negative electrode current collector. As with the positive electrode, the viscosity and stretching of the polymer itself of the present invention are used. You can also

  The current collector for the negative electrode is, for example, a foil or a non-woven fabric such as Cu, Ni, or stainless steel.

  Moreover, the separator used as needed is an insulating film having high ion permeability and excellent mechanical strength. For example, a woven cloth, a porous film such as polyethylene, polypropylene, or the like is used.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the technical scope of the present invention is not limited thereto.

Example 1.3 Synthesis of 3-propoxy-propanenitrile 3-ethyl-3-oxetanoate, 1CEES

A 2 wt% aqueous sodium hydroxide solution (150 g), dichloromethane (150 mL), 1,3-propanediol (86.1 mL, 1.2 mol) and acrylonitrile (26.2 mL, 0.4 mol) were added to the eggplant flask, Stir for hours. After completion of the reaction, the mixture was extracted 3 times with dichloromethane (150 mL), and the organic layer was dehydrated with anhydrous magnesium sulfate. The solvent was removed from the obtained organic layer under reduced pressure using a rotary evaporator, and the obtained residue was purified by column chromatography (silica gel / ethyl acetate: hexane 3: 1) to obtain 1CE as a colorless liquid.
In an eggplant flask, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) (23.00 g, 0.12 mol), ECO synthesized by a known method (Japanese Patent Laid-Open No. 2013-043880) (13 0.01 g, 0.1 mol), 1CE (12.90 g, 0.1 mol), 4-dimethylaminopyridine (DMAP) (6.11 g, 0.05 mol) and dichloromethane (150 mL) were added, and the mixture was stirred at room temperature for 16 hours. did. After completion of the reaction, washing was performed twice with brine (150 mL). Thereafter, the organic layer was dehydrated with anhydrous magnesium sulfate. The solvent was removed from the obtained organic layer under reduced pressure using a rotary evaporator, and the resulting residue was purified by column chromatography (silica gel / ethyl acetate-hexane 2: 3) to obtain the desired product (1CEES) as a colorless liquid. Got as. ¹ HNMR of the obtained 1CEES is shown in FIG. 1, ¹³ CNMR is shown in FIG. 2, and FT-IR is shown in FIG.

Example 2.2, 2-[(2-cyanoethoxy) methyl] -butane 3-ethyl-3-oxetanoate (2,2-[(2-cyanoethoxy) methyl] -butane 3-ethyl-3-oxetanoate, 2CEES ) Synthesis

A 2 wt% aqueous sodium hydroxide solution (150 mL), 1,1,1-tris (hydroxymethyl) propane (40.25 g, 0.3 mol), and dichloromethane (150 mL) were added to the eggplant flask. Acrylonitrile (43.2 mL, 0.66 mol) was added while the mixture was refluxed, and the mixture was stirred at room temperature for 24 hours. After completion of the reaction, it was washed twice with water (150 mL), and the organic layer was dehydrated with anhydrous magnesium sulfate. The obtained organic layer was subjected to removal of the solvent under reduced pressure using a rotary evaporator, and the obtained residue was purified by column chromatography (silica gel / acetonitrile: toluene 1: 4) to obtain 2CE as a colorless liquid.
In a recovery flask, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) (16.24 g, 0.0847 mol), ECO (9.18 g, 0.0706 mol), 2CE (16.95 g, 0 0.0706 mol), 4-dimethylaminopyridine (DMAP) (4.31 g, 0.0353 mol) and dichloromethane (200 mL) were added, and the mixture was stirred at room temperature for 16 hours. After completion of the reaction, washing with water (150 mL) was performed twice. Thereafter, the organic layer was dehydrated with anhydrous magnesium sulfate. The solvent was removed from the resulting organic layer under reduced pressure using a rotary evaporator, and the resulting residue was purified by column chromatography (silica gel / ethyl acetate-hexane 1: 1) to obtain the desired product (2CEES) as a colorless liquid. Got as. FIG. 4 shows the ¹ HNMR of the obtained 2CEES, FIG. 5 shows the ¹³ CNMR, and FIG. 6 shows the FT-IR.

Example 3. 2,2-bis [(2-cyanoethoxy) methyl] -3-propoxy-propanenitrile 3-ethyl-3-oxetanoate (2, 2-bis [(2-cyanoethoxy) methyl] -3-propoxy -propanenitrile 3-ethyl-3-oxetanoete, 3CEES)

A 2 wt% aqueous sodium hydroxide solution (75 mL), pentaerythritol (20.42 g, 0.15 mol), dichloromethane (75 mL) and acrylonitrile (31.44 mL, 0.48 mol) were added to the eggplant flask and refluxed for 13 hours. After completion of the reaction, it was washed twice with water (75 mL), and the organic layer was dehydrated with anhydrous magnesium sulfate. The solvent was removed from the resulting organic layer under reduced pressure using a rotary evaporator, and the resulting residue was purified by column chromatography (silica gel / ethyl acetate: hexane 2: 1) to obtain 3CE as a colorless liquid.
In a recovery flask, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) (11.41 g, 0.0595 mol), ECO (6.45 g, 0.0496 mol), 3CE (14.65 g, 0 4.096 mol), 4-dimethylaminopyridine (DMAP) (3.03 g, 0.0248 mol) and dichloromethane (140 mL) were added, and the mixture was stirred at room temperature for 40 hours. After completion of the reaction, washing was performed twice with water (100 mL). Thereafter, the organic layer was dehydrated with anhydrous magnesium sulfate. The solvent was removed from the obtained organic layer under reduced pressure using a rotary evaporator, and the obtained residue was purified by column chromatography (silica gel / ethyl acetate-hexane 3: 2) to obtain the desired product (3CEES) as a colorless liquid. Got as. FIG. 7 shows ¹ HNMR of the obtained 3CEES, FIG. 8 shows ¹³ CNMR, and FIG. 9 shows FT-IR.

Example 4 Synthesis of P1CEES

1CEES (1.00 g, 0.00415 mol) was added to a 30 mL eggplant flask. Next, BF ₃ .Et ₂ O (0.261 mL, 0.00207 mol) was added and stirred at room temperature. After stirring for 1 minute, the stirring bar stopped rotating, and then left to stand for 10 minutes. Next, dichloromethane (5 mL) was added to dissolve, and ethanol (2 mL) was added to stop the reaction. After stopping the reaction, the solvent was removed under reduced pressure using a rotary evaporator. Thereafter, dichloromethane was added as a good solvent and ethanol was added as a poor solvent, followed by reprecipitation seven times. After reprecipitation, it was dried under reduced pressure at 80 ° C. for 16 hours to obtain 0.45 g of pale yellow P1CEES (yield 45%, number average molecular weight: about 2700 g / mol). FIG. 10 shows the ¹ HNMR of the obtained P1CEES, FIG. 11 shows the FT-IR, and FIG. 12 shows the GPC chart.

Embodiment 5 FIG. Synthesis of P2CEES

2CEES (1.00 g, 0.00284 mol) was added to a 30 mL eggplant flask. Next, BF ₃ .Et ₂ O (0.358 mL, 0.00284 mol) was added at room temperature and stirred. After stirring for 1 hour, the stirring bar stopped rotating, and then allowed to stand for 36 hours. Next, dichloromethane (5 mL) was added to dissolve, and ethanol (2 mL) was added to stop the reaction. After stopping the reaction, the solvent was removed under reduced pressure using a rotary evaporator. Thereafter, dichloromethane was added as a good solvent and ethanol was added as a poor solvent, followed by reprecipitation three times. After reprecipitation, it was dried under reduced pressure at 80 ° C. for 24 hours to obtain 0.72 g of pale yellow P2CEES (yield 72%, number average molecular weight: about 3700 g / mol). FIG. 13 shows the ¹ HNMR of the obtained P2CEES, FIG. 14 shows the FT-IR, and FIG. 15 shows the GPC chart.

Example 6 Synthesis of P3CEES

3CEES (1.00 g, 0.00246 mol) was added to a 30 mL eggplant flask. Next, BF ₃ .Et ₂ O (0.310 mL, 0.00246 mol) was added at room temperature and stirred. After stirring for 1 hour, the stirring bar stopped rotating, and then left to stand for 30 minutes. Next, dichloromethane (5 mL) was added to dissolve, and ethanol (2 mL) was added to stop the reaction. After stopping the reaction, the solvent was removed under reduced pressure using a rotary evaporator. Thereafter, dichloromethane was added as a good solvent and ethanol was added as a poor solvent, followed by reprecipitation five times. After reprecipitation, it was dried under reduced pressure at 80 ° C. for 16 hours to obtain 0.82 g of pale yellow P3CEES (yield 82%, number average molecular weight: about 1900 g / mol). FIG. 16 shows the ¹ HNMR of the obtained P3CEES, FIG. 17 shows the FT-IR, and FIG. 18 shows the GPC chart.

Example 7 Preparation of electrolyte membrane containing P1CEES

P1CEES electrolyte membranes were prepared by changing the ratio of the amount of Li / CN substance in the following procedure. Li / CN represents the amount of lithium per mol of nitrile group. For example, in a film containing P1CEES and vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) at a weight ratio of 1: 1, 1 mol of nitrile group When 0.5TFol of LiTFSA is included, it is expressed as Li / CN = 0.557.
LiTFSA and 2 mL of acetone were added to the sample tube to dissolve LiTFSA. This solution was added to the sample tube containing P1CEES and PVDF-HFP obtained in Example 4 and stirred at room temperature for 4 hours. The obtained mixed solution is poured onto a Teflon (registered trademark) plate, cast on a Teflon (registered trademark) plate using a plate, etc., and the solvent is removed at 60 ° C. under reduced pressure for 17 hours. The film was formed. The amount of LiTFSA, P1CEES, PVDF-HFP mixed is shown in Table 2 below.

Example 8 FIG. Preparation of electrolyte membrane containing P2CEES

P2CEES electrolyte membranes were prepared by changing the Li / CN substance amount ratio in the following procedure.
LiTFSA and 2 mL of acetone were added to the sample tube to dissolve LiTFSA. This solution was added to the sample tube containing P2CEES and PVDF-HFP obtained in Example 5, and stirred at room temperature for 15 hours. The obtained mixed solution is poured onto a Teflon (registered trademark) plate and cast on a Teflon (registered trademark) plate using a plate or the like, and the solvent is removed at 80 ° C. under reduced pressure for 21 hours. The film was formed. The amount of LiTFSA, P2CEES, PVDF-HFP mixed is shown in Table 3 below.

Example 9 Preparation of electrolyte membrane containing P3CEES

P3CEES electrolyte membranes were prepared by changing the ratio of the amount of Li / CN substances in the following procedure.
LiTFSA and 2 mL of acetone were added to the sample tube to dissolve LiTFSA. This solution was added to the sample tube containing P3CEES and PVDF-HFP obtained in Example 6 and stirred at room temperature for 4 hours. The obtained mixed solution is poured onto a Teflon (registered trademark) plate, cast on a Teflon (registered trademark) plate using a plate, etc., and the solvent is removed at 60 ° C. under reduced pressure for 17 hours. The film was formed. The amount of LiTFSA, P3CEES, PVDF-HFP mixed is shown in Table 4 below.

Example 10 Measurement of ionic conductivity of electrolyte membrane

The ionic conductivity of the polymer solid electrolyte membranes produced in Examples 7 to 9 was measured by the AC impedance method. The measurement sample is a polymer solid electrolyte membrane cut into a circle with a diameter of 1.5 cm, and is controlled using a screw cell in a thermostatic chamber [Tokyo Rika Kikai Co., Ltd. EYELA PRO COOL BATH NCB-3100]. Measurements were made in a temperature range of ˜70 ° C. For the measurement, an LCR meter [Hioki Electric Co., Ltd. 3532-80 CHEMICAL IMPEDANCE METER] was used. Moreover, the ionic conductivity was calculated using the following formula.
[Formula 1]
σ = d / (SZ (cos θ))
(In the formula, σ is conductivity (S / cm), d is the thickness of the sample (cm), S is the area of the sample (cm ² , Z is impedance (Ω), and θ is the phase angle).
FIG. 19 shows the ionic conductivity at each Li / CN value of P1CEES. FIG. 20 shows the ionic conductivity at each Li / CN value of P2CEES. FIG. 21 shows the ionic conductivity at each Li / CN value of P3CEES.
The larger the σ value, the higher the ionic conductivity, and it became clear that P3CEES has the highest ionic conductivity regardless of the lithium salt concentration. Moreover, it became clear that in all of P1CEES, P2CEES, and P3CEES, the ionic conductivity was high when the lithium salt concentration was 0.557.

Example 11 P1CEES measured synthesis of the glass transition point _{(T g),} it was carried out P2CEES, P3CEES and glass transition point _{(T g)} Differential scanning calorimetry of the electrolyte membrane produced from them (Differential scanning calorimetry, DSC) by.
For measurement, each sample is weighed 2 to 5 mg in a predetermined aluminum sealed container, sealed with a sample sealer, and set in a measuring apparatus together with a standard sample packed with 2 to 5 mg α-alumina in another sealed container. Measurements were made. The measurement conditions were a temperature rise rate and a temperature drop rate of 10 ° C./min, and measurement was performed in a temperature range of −100 to 100 ° C.
For the measurement, differential scanning calorimetry [Bruker AXS DSC3100S] was used.
Table 5 shows the T _g of each polymer.
Table 6 shows the T _{g of the} electrolyte membrane containing P1CEES.
Table 7 shows the T _{g of the} electrolyte membrane containing P2CEES.
Table 8 shows the T _{g of the} electrolyte membrane containing P3CEES.

  It was found that each of the P1CEES, P2CEES, and P3CEES polymers and the electrolyte membrane containing the polymer had a low glass transition temperature and excellent flexibility at room temperature.

  The solid electrolyte of the present invention does not contain a flammable solvent contained in a normal battery, and has little risk of liquid leakage or fire. Therefore, it can be used for batteries that require safety, such as electric vehicles and large-sized secondary batteries for home use. Further, since the electrolyte of the present invention is solid, there is an advantage that the shape of the battery can be freely set. Furthermore, the solid electrolyte of the present invention has flexibility and excellent adhesion to the electrode.

Claims (16)

An oxetane compound represented by formula (1).

[Wherein, R ¹ represents a C1-C6 alkyl group. R ² represents a C1-C4 alkylene group. R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom, a C1-C10 alkyl group, or a group having a nitrile group at the terminal represented by the formula (2).

Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). And the wavy line represents a covalent bond to a carbon atom. However, at least one of R ³ , R ⁴ and R ⁵ is a group having a nitrile group at the terminal represented by the formula (2). ] R ³ is a group having a nitrile group at the terminal represented by the formula (2)

Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). The wavy line represents a covalent bond to a carbon atom.) And R ⁴ and R ⁵ are a hydrogen atom or a C1-C10 alkyl group. R ³ and R ⁴ are groups having a nitrile group at the terminal represented by the formula (2)

Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). The wavy line represents a covalent bond to a carbon atom.), And R ⁵ is a hydrogen atom or a C1-C10 alkyl group. R ³ , R ⁴ and R ⁵ are all groups having a nitrile group at the terminal represented by the formula (2)

Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). The wavy line represents a covalent bond to a carbon atom.) The compound according to claim 1. A group having a nitrile group at the terminal represented by the formula (2)
The compound according to any one of claims 1 to 4. R ¹ is an ethyl group, R ² is a methylene group, and the group represented by the formula (2) has a nitrile group at the terminal.
The compound according to any one of claims 1 to 4. A polymer having a repeating unit represented by formula (3).

[Wherein, R ¹ represents a C1-C6 alkyl group. R ² represents a C1-C4 alkylene group. R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom, a C1-C10 alkyl group, or a group having a nitrile group at the terminal represented by the formula (2).

Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). And the wavy line represents a covalent bond to a carbon atom. However, at least one of R ³ , R ⁴ and R ⁵ is a group having a nitrile group at the terminal represented by the formula (2). n represents the number of repeating units. ] R ³ is a group having a nitrile group at the terminal represented by the formula (2)

Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). The wavy line represents a covalent bond to a carbon atom.), And R ⁴ and R ⁵ are a hydrogen atom or a C1-C10 alkyl group. R ³ and R ⁴ are groups having a nitrile group at the terminal represented by the formula (2)

Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). And the wavy line represents a covalent bond to a carbon atom.) And R ⁵ is a hydrogen atom or a C1-C10 alkyl group. R ³ , R ⁴ and R ⁵ are all groups having a nitrile group at the terminal represented by the formula (2)

Wherein R ⁶ is a C1-C10 alkylene group which may contain one or more groups selected from the group consisting of ether (—O—), sulfide (—S—) and amine (—NH—). The wavy line represents a covalent bond to a carbon atom.) The polymer of claim 7. A group having a nitrile group at the terminal represented by the formula (2) is
The polymer according to any one of claims 7 to 10. R ¹ is an ethyl group, R ² is a methylene group, and the group represented by the formula (2) has a nitrile group at the terminal.
The polymer according to any one of claims 7 to 10.   A solid electrolyte comprising the polymer according to claim 7.   The solid electrolyte according to claim 13, comprising an ion carrier.   The solid electrolyte according to claim 13 or 14, further comprising a reinforcing material. A battery comprising the solid electrolyte according to claim 13.