JP6895678B2 - Supramolecular complex manufacturing method, supramolecular complex and electrolyte - Google Patents

Description

The present invention relates to a method for producing a supramolecular complex, a supramolecular complex and an electrolyte, and for example, a method for producing a supramolecular complex containing a boroxine compound, a supramolecular complex and an electrolyte.

Conventionally, a polymer electrolyte containing a boroxine compound has been proposed (see, for example, Patent Document 1). In the polymer electrolyte described in Patent Document 1, by adding a boroxine compound to the polymer electrolyte, an anion trapping effect derived from the boroxine ring of the boroxine compound can be obtained. This makes it possible to improve battery characteristics such as positive electrode capacity and cycle characteristics when the polymer electrolyte is used as a binder for the positive electrode of a polymer lithium battery.

Japanese Unexamined Patent Publication No. 2004-6237

By the way, in lithium ion secondary batteries (LiB: Li ion secondary batteries), an organic electrolyte having volatile and flammable properties is being replaced with a solid electrolyte having excellent safety and functionality. However, with conventional solid electrolytes, the ionic conductivity is as low as about 10% of that of organic electrolytes, and the lithium ion transport number is about 30% of the total ions, so that the electrochemical characteristics can be sufficiently adapted to high-speed charging and discharging. There is a fact that I do not have.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for producing a supramolecular complex, a supramolecular complex, and an electrolyte, which can obtain an electrolyte having excellent electrochemical properties.

（上記式（１）中、Ｒ_１は、２価の脂肪族基、２価の脂環族基、又は２価の芳香族基を表す。） The method for producing a supramolecular complex of the present invention is characterized by comprising a step of dehydrating and condensing diboronic acid represented by the following general formula (1) in the presence of polyalkylene oxide diamine to obtain a supramolecular complex. To do.

(In the above formula (1), R ₁ represents a divalent aliphatic group, a divalent alicyclic group, or a divalent aromatic group.)

According to this method, since the boroxine ring of the boroxine compound formed by dehydration condensation of diboronic acid has electrophilicity, the anion coordination ability is improved and the anion is easily captured, and the ionic conductivity and the lithium ion transport number are improved. Is improved. In addition, since the polyalkylenediamine intervenes between the boroxine compounds, an amino group is coordinated with the boroxine ring to improve the stability against hydrolysis between the boroxines. Therefore, it is possible to realize a method for producing a supramolecular complex in which an electrolyte having excellent electrochemical properties can be obtained.

（上記式（２）中、Ｒ_２、Ｒ_３、及びＲ_４は、それぞれ独立して、水素原子、又は炭素数１以上１０以下の炭化水素基を表す。ｘ、及びｚは、１以上１００以下の整数である。ｙは、０以上７０以下の整数である。ｘ＋ｚは、２以上１００以下の整数である。） In the method for producing a supramolecular complex of the present invention, the polyalkylene oxide diamine is preferably represented by the following general formula (2). By this method, the flexibility of the molecular chain of the polyalkylene diamine is improved, so that it is possible to obtain an electrolyte excellent in ionic conductivity and lithium ion transport number.

(In the above formula (2), R ₂ , R ₃ , and R ₄ independently represent a hydrogen atom or a hydrocarbon group having 1 or more and 10 or less carbon atoms. X and z are 1 or more and 100. The following integers. Y is an integer of 0 or more and 70 or less. X + z is an integer of 2 or more and 100 or less.)

In the method for producing a supramolecular complex of the present invention, it is preferable that the polyalkylene oxide diamine is at least one selected from the group consisting of an ethylene oxide polymer, a propylene oxide polymer and an ethylene oxide propylene oxide copolymer. .. By this method, the flexibility of the molecular chain of the polyalkylene diamine is improved, so that it is possible to obtain an electrolyte excellent in ionic conductivity and lithium ion transport number.

In the method for producing a supramolecular complex of the present invention, it is preferable that the diboronic acid is at least one selected from the group consisting of phenylenediboronic acid and phenylenediboronic acid derivatives. By this method, the electrophilicity of the boroxin ring of the boroxine compound formed by dehydration condensation of diboronic acid is further improved, so that an electrolyte having further excellent ionic conductivity and lithium ion transport number can be obtained.

（上記式（３）中、Ｒ_５、Ｒ_６、Ｒ_７は、２価の脂肪族基、２価の脂環族基、又は２価の芳香族基を表す。） The supramolecular complex of the present invention is characterized in that a polyalkylene oxide diamine is interposed between boroxine compounds containing a repeating structural unit represented by the following general formula (3).

(In the above formula (3), R ₅ , R ₆ , and R ₇ represent a divalent aliphatic group, a divalent alicyclic group, or a divalent aromatic group.)

According to this configuration, since the boroxine ring of the booxine compound represented by the above general formula (3) has electrophilicity, the anion coordination ability is improved, the anion is easily captured, and the lithium ion transport number is improved. To do. In addition, since the polyalkylenediamine intervenes between the boroxine compounds, an amino group is coordinated with the boroxine ring to improve the stability against hydrolysis between the boroxines. Therefore, it is possible to realize a supramolecular complex in which an electrolyte having excellent electrochemical properties can be obtained.

（上記式（２）中、Ｒ_２、Ｒ_３、及びＲ_４は、それぞれ独立して、水素原子、又は炭素数１以上１０以下の炭化水素基を表す。ｘ、及びｚは、１以上１００以下の整数である。ｙは、０以上７０以下の整数である。ｘ＋ｚは、２以上１００以下の整数である。） In the supramolecular complex of the present invention, the polyalkylene oxide diamine is preferably represented by the following general formula (2). With this configuration, the flexibility of the molecular chain of the polyalkylene diamine is improved, so that it is possible to obtain an electrolyte excellent in ionic conductivity and lithium ion transport number.

(In the above formula (2), R ₂ , R ₃ , and R ₄ independently represent a hydrogen atom or a hydrocarbon group having 1 or more and 10 or less carbon atoms. X and z are 1 or more and 100. The following integers. Y is an integer of 0 or more and 70 or less. X + z is an integer of 2 or more and 100 or less.)

In the supramolecular composite of the present invention, the polyalkylene oxide diamine is preferably at least one selected from the group consisting of ethylene oxide polymers, propylene oxide polymers and ethylene oxide propylene oxide copolymers. By this method, the flexibility of the molecular chain of the polyalkylene diamine is improved, so that it is possible to obtain an electrolyte excellent in ionic conductivity and lithium ion transport number.

The electrolyte of the present invention is characterized by containing the supramolecular complex.

According to this configuration, since the boroxine ring of the boroxine compound formed by dehydration condensation of diboronic acid has electrophilicity, the anion coordination ability is improved, the anion is easily captured, and the lithium ion transport number is improved. In addition, since the polyalkylenediamine intervenes between the boroxine compounds, an amino group is coordinated with the boroxine ring to improve the stability against hydrolysis between the boroxines. Therefore, an electrolyte having excellent electrochemical characteristics can be realized.

According to the present invention, it is possible to realize a method for producing a supramolecular complex, a supramolecular complex, and an electrolyte, which can obtain an electrolyte having excellent electrochemical properties.

FIG. 1 is an explanatory diagram of dehydration condensation of diboronic acid in the method for producing a supramolecular complex according to the present embodiment. FIG. 2 is a diagram showing a reaction formula of dehydration condensation of diboronic acid in the method for producing a supramolecular complex according to the present embodiment. FIG. 3 is a conceptual diagram of the supramolecular complex according to the present embodiment. FIG. 4 is an explanatory diagram of an electrolyte using the supramolecular complex according to the present embodiment. FIG. 5 is an explanatory diagram of an electrolyte using the supramolecular complex according to the present embodiment. FIG. 6 is a diagram showing the measurement results ^{of 11} B-NMR of the supramolecular complex obtained in Example 1. FIG. 7 is a diagram showing the measurement results of the infrared absorption spectrum of the supramolecular complex obtained in Example 1. FIG. 8A is a scanning electron micrograph of the raw material 1,4-phenylenediboronic acid used in Example 1. FIG. 8B is a scanning electron micrograph of the dehydrated condensate of 1,4-phenylenediboronic acid according to Example 1. FIG. 8C is a scanning electron micrograph of the supramolecular complex obtained in Example 1. FIG. 9 is a diagram showing the result of the LSV evaluation according to the first embodiment. FIG. 10 is a diagram showing the results of the CV evaluation according to the first embodiment. FIG. 11 is a diagram showing the results of the CV evaluation according to the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments, and can be modified as appropriate.

（上記式（１）中、Ｒ_１は、２価の脂肪族基、２価の脂環族基、又は２価の芳香族基を表す。） (Method of producing supramolecular complex)
The method for producing a supramolecular complex according to the present embodiment includes a step of dehydrating and condensing diboronic acid represented by the following general formula (1) in the presence of polyalkylene oxide diamine to obtain a supramolecular complex.

(In the above formula (1), R ₁ represents a divalent aliphatic group, a divalent alicyclic group, or a divalent aromatic group.)

FIG. 1 is an explanatory diagram of dehydration condensation of diboronic acid in the method for producing a supramolecular complex according to the present embodiment. Note that FIG. 1 shows an example in which 1,4-phenylenediboronic acid is used as the diboronic acid 11 represented by the general formula (1). As shown in FIG. 1, the diboronic acid 11 is increased in quantity by dehydration condensation to become a boroxine compound (boroxine dehydration condensate) 12 having a plurality of boroxine rings 12A. This booxine ring 12A becomes a plane six-membered ring isoelectronic with benzene because an empty p-orbital on a boron atom and an unshared electron pair on oxygen form a π bond. As a result, the boroxine compound 12 has a structure in which a plurality of diboronic acids 11 are quantified by dehydration condensation and extend in a plane.

FIG. 2 is a diagram showing a reaction formula of dehydration condensation of diboronic acid in the method for producing a supramolecular complex according to the present embodiment. Note that FIG. 2 shows an example in which 1,4-phenylenediboronic acid is used as the diboronic acid 11 represented by the general formula (1), as in FIG. Further, in FIG. 2, n of the polyalkylene oxide diamine 13 represents a predetermined integer. As shown in FIG. 2, in the method for producing a supramolecular complex according to the present embodiment, diboronic acid 11 and polyalkylene oxide diamine 13 are mixed in advance, and then diboronic acid 11 is dehydrated and condensed. By this dehydration condensation, a plurality of diboronic acids 11 are dehydrated and condensed to form planar boroxine compounds 121 and 122, respectively, and the polyalkylene oxide diamine 13 is interposed between the boroxine compounds 121 and 122. It becomes. As a result, a supramolecular complex 14 in which the alkylene oxide diamine 13 is interposed between the pair of boroxine compounds 121 and 122 is obtained.

FIG. 3 is a conceptual diagram of the supramolecular complex 14 according to the present embodiment. As shown in FIG. 3, the supramolecular complex 14 contains a plurality of flat plate-shaped boroxine compounds 12 (five in the present embodiment) formed by dehydration condensation of a plurality of diboronic acids, and the plurality of boroxine compounds 12 The polyalkylene oxide diamine 13 is interposed between them. In the example shown in FIG. 3, the polyalkylene oxide diamine 131 is interposed between the boroxine compounds 121 and 122, the polyalkylene oxide diamine 132 is interposed between the boroxine compounds 123 and 124, and the polyalkylene oxide diamine 133 is interposed between the boroxine compounds 121 and 125. Intervening, polyalkylene oxide diamine 134 is intervening between boroxine compounds 124 and 125. Although the detailed structure of the supramolecular complex 14 is not always clear, the nitrogen atoms of the two amino groups of the polyalkylene oxide diamine 13 are coordinated on the boron atom of the booxine ring 12A of the booxine compound 12, respectively. It is thought that there is. As a result, a supramolecular complex 14 in which a crosslink is formed between the boroxine compounds 12 by the polyalkylene oxide diamine 13 is obtained.

FIG. 4 is an explanatory diagram of an electrolyte using the supramolecular complex 14 according to the present embodiment. In FIG. 4, the periphery of the boroxine ring 12A of the boroxine compound of the supramolecular complex 14 is shown enlarged. As shown in FIG. 4, in the present embodiment, the electrophilic booxine ring 12A has an anion coordinating ability to coordinate and capture the anion 21 present in the electrolyte 20. As a result, the movement of the anion 21 in the electrolyte 20 is suppressed, so that the movement of the lithium ion 22 as a cation that becomes the counter ion of the anion 21 becomes easy, and the ionic conductivity and the lithium ion transport number in the electrolyte 20 are improved. To do.

FIG. 5 is an explanatory diagram of an electrolyte using the supramolecular complex 14 according to the present embodiment. In FIG. 5, the central portion of the polyalkylene oxide diamine 13 of the supramolecular complex 14 is shown in an enlarged manner. As shown in FIG. 5, since the molecular structure of the linear alkylene oxide of the polyalkylene oxide diamine 13 is maintained in the central portion of the polyalkylene oxide diamine 13, it is interposed between the molecular chains of the polyalkylene oxide diamine 13. The anion 21 and the lithium ion 22 can move rapidly, and the ionic conductivity and the lithium ion transport number of the electrolyte 20 are improved. Further, it is also possible to maintain the motility of the molecular chain of the polyalkylene oxide diamine 13 to form a film.

As the diboronic acid, the one represented by the above general formula (1) is used. The divalent aliphatic group and the divalent aromatic group in _{R 1} of the general formula (1) may have a substituent or may be unsubstituted. Examples of the substituent here include an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an alkenyl group, an alkynyl group, a silyl group, a halogen atom, an acyl group, an acyloxy group and an oxycarbonyl group. , Carboxy group, hydroxy group, nitro group, cyano group and the like. These substituents may further have the above-mentioned substituents.

_{Examples of the divalent aliphatic group in R 1} of the general formula (1) include an alkylene group and an alkylidene group. The number of carbon atoms of the divalent aliphatic group is preferably 1 or more and 10 or less, and more preferably 3 or more and 7 or less. The divalent aliphatic group may be a linear group or a branched chain group. Examples of the divalent aliphatic group include a methylene group, an ethylene group, a propylidene group, a propylene group, a trimethylene group, an isopropylidene group, a tetramethylene group, a butylidene group, an isobutylidene group, a sec-butylidene group and an isobutylene group. Be done.

_{Examples of the divalent alicyclic group in R 1} of the general formula (1) include a cycloalkylene group and a cycloalkylidene group. The number of carbon atoms of the divalent alicyclic group is preferably 5 or more and 15 or less, and more preferably 4 or more and 7 or less. Examples of the divalent alicyclic group include a cyclobutanediyl group, a cyclopentanediyl group and a cyclohexanediyl group.

_{Examples of the divalent aromatic group in R 1} of the general formula (1) include an arylene group. The number of carbon atoms of the arylene group is preferably 6 or more and 60 or less, and more preferably 6 or more and 30 or less. The arylene group includes a group having a benzene ring and a group having a condensed ring. Examples of the arylene group include a phenylene group such as a 1,4-phenylene group, a 1,3-phenylene group and a 1,2-phenylene group, a 1,4-naphthalenedyl group, a 1,5-naphthalenedyl group, and a 2, 6-Naphthalenediyl group, Naphthalenediyl group such as 2,7-Naphthalenediyl group, 1,4-Anthracendyl group, 1,5-Anthracendyl group, 2,6-Anthracendyl group, 9,10-Anthracendyl group, etc. Anthracendyl group, phenanthrendiyl group such as 2,7-phenanthrendiyl group, 1,7-naphthacendyl group, 2,8-naphthacendyl group, naphthacendyl group such as 5,12-naphthacendyl group, 2,7-full orangeyl group. Group, full-orange-yl group such as 3,6-full-orange-yl group, 1,6-pyreneyl group, 1,8-pyreneyl group, 2,7-pyrerangeil group, 4,9-pyrerangeil group and other pyrienyl groups, 3 , 8-Perylene diyl group, 3,9-perylene diyl group, 3,10-perylene diyl group and the like.

_{Among these, R 1} of the above general formula (1) is a divalent group having 6 or more and 30 or less carbon atoms from the viewpoint of improving ionic conductivity and lithium ion transport rate and obtaining an electrolyte having excellent electrochemical characteristics. The arylene group is preferable, a phenylene group, a naphthalenediyl group, an anthracendiyl group, a phenanthrenidyl group, a naphthalsendiyl group, a full orangeyl group, a pyrenyl group and a perylenediyl group are more preferable, a phenylene group is further preferable, and a 1,4-phenylene group is preferable. Is even more preferable.

As the diboronic acid represented by the above general formula (1), phenylenediboronic acid, naphthalenediboronic acid, and the like, from the viewpoint of improving the ionic conductivity and the lithium ion transport rate and obtaining an electrolyte having excellent electrochemical characteristics. At least one selected from the group consisting of anthracendiboronic acid, phenanthrenediboronic acid, naphthacendiboronic acid, fluorangeboronic acid, pyrenediboronic acid and peryleneboronic acid, and derivatives thereof is preferable, and phenylenediboronic acid is preferable. , Naphthalenediboronic acid and anthracendiboronic acid, and at least one selected from the group consisting of these derivatives is more preferable, and at least one selected from the group consisting of phenylenediboronic acid and phenylenediboronic acid derivatives. Is more preferable, and at least one selected from the group consisting of 1,4-phenylenediboronic acid and 1,4-phenylenediboronic acid derivatives is particularly preferable.

Examples of the polyalkylene oxide diamine include an alkylene oxide polymer having an amino group at both ends and an alkylene oxide copolymer. Examples of the alkylene oxide copolymer include an ethylene oxide copolymer, a propylene oxide copolymer, and a butylene oxide copolymer. Examples of the alkylene oxide copolymer include block copolymers such as random copolymers, diblock copolymers, triblock copolymers and tetrablock copolymers. Among these, as the alkylene oxide copolymer, a diblock copolymer or triblock of an alkylene oxide can be obtained from the viewpoint of improving the flexibility of the molecular chain and obtaining an electrolyte excellent in ionic conductivity and lithium ion transport rate. Copolymers are preferred, and triblock copolymers are preferred. Examples of the alkylene oxide used for the copolymer include ethylene oxide, propylene oxide and butylene oxide.

Among these, as polyalkylene oxide diamine, ethylene oxide polymer, propylene oxide polymer and ethylene oxide propylene oxide can be obtained from the viewpoint of improving the flexibility of the molecular chain and obtaining an electrolyte excellent in ionic conductivity and lithium ion transport number. It is preferably at least one selected from the group consisting of copolymers.

（上記式（２）中、Ｒ_２、Ｒ_３、及びＲ_４は、それぞれ独立して、水素原子、又は炭素数１以上１０以下の炭化水素基を表す。ｘ、及びｚは、１以上１００以下の整数である。ｙは、０以上７０以下の整数である。ｘ＋ｚは、２以上１００以下の整数である。） Further, as the polyoxyalkylene diamine, those represented by the following general formula (2) are preferable from the viewpoint of improving the flexibility of the molecular chain and obtaining an electrolyte having excellent ionic conductivity and lithium ion transport number.

(In the above formula (2), R ₂ , R ₃ , and R ₄ independently represent a hydrogen atom or a hydrocarbon group having 1 or more and 10 or less carbon atoms. X and z are 1 or more and 100. The following integers. Y is an integer of 0 or more and 70 or less. X + z is an integer of 2 or more and 100 or less.)

_{The hydrocarbon group having 1 or more and 10 or less carbon atoms in R 2} , R ₃ and R ₄ of the above general formula (2) may have a substituent or may be a non-substituted hydrocarbon group. .. The substituent here may be the same as the substituents exemplified in the description of R ₁ in the formula (1) described above. Further, the hydrocarbon groups having 1 or more and 10 or less carbon atoms in _{R 2} , R ₃ and R ₄ of the above formula (2) may have an ether bond. The _{number of carbon atoms of the hydrocarbon groups in R 2} , R ₃ , and R ₄ is more preferably 1 or more and 5 or less, and further preferably 1 or more and 3 or less.

_{Examples of the hydrocarbon group having 1 or more and 10 or less carbon atoms in R 2} , R ₃ and R ₄ of the above general formula (2) include methyl group, ethyl group, propyl group, isopropyl group, butyl group and sec-butyl. Group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group, methoxymethyl group, methoxyethyl group, methoxypropyl group, methoxybutyl group, methoxypentyl group, methoxyhexyl Group, methoxyheptyl group, methoxyoctyl group, methoxynonyl group, methoxydecyl group, ethoxymethyl group, ethoxyethyl group, ethoxypropyl group, ethoxybutyl group, ethoxypentyl group, ethoxyhexyl group, ethoxyheptyl group, ethoxyoctyl group, Examples thereof include an ethoxynonyl group and an ethoxydecyl group. Among these, R _{2, R 3,} and as R _4, from the viewpoint of improved flexibility of the molecular chain of polyalkylene amine ion conductivity and lithium ion transport number by excellent electrolyte can be obtained, a hydrogen atom, Methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group and pentyl group are preferable, and hydrogen atom, methyl group, ethyl group, propyl group and isopropyl group are more preferable. , Hydrogen atom, methyl group and ethyl group are more preferable.

The x and z in the general formula (2) are 1 or more and 70 or less from the viewpoint of improving the flexibility of the molecular chain of the polyalkylene diamine and obtaining an excellent electrolyte with ionic conductivity and lithium ion transport number. An integer is preferable, 2 or more and 50 or less is more preferable, and 3 or more and 10 or less is further preferable. As y in the above general formula (2), an integer of 25 or more and 60 or less is preferable from the viewpoint of improving the flexibility of the molecular chain of the polyalkylene diamine and obtaining an electrolyte excellent in ionic conductivity and lithium ion transport number. , An integer of 30 or more and 50 or less is more preferable. As x + z in the above general formula (2), an integer of 2 or more and 10 or less is preferable from the viewpoint of improving the flexibility of the molecular chain of the polyalkylene diamine and obtaining an electrolyte excellent in ionic conductivity and lithium ion transport number. An integer of 2 or more and 70 or less is more preferable, an integer of 3 or more and 50 or less is further preferable, and an integer of 4 or more and 10 or less is further preferable.

The weight average molecular weight of the polyalkylene oxide diamine is preferably 500 g / mol or more and 5000 g / mol or less, preferably 1000 g / mol, from the viewpoint of improving the ionic conductivity and the lithium ion transport rate and obtaining an electrolyte having excellent electrochemical characteristics. More than 4000 g / mol is more preferable, and 1500 g / mol or more and 3000 g / mol or less is further preferable.

Examples of the polyalkylene oxide diamine represented by the general formula (2) include Jeffamine (registered trademark) (model numbers "ED-2003", "D-2000", "D-4000", manufactured by Huntsman) and the like. Commercially available products may be used.

In the present embodiment, boronic acid represented by the general formula (1) and polyalkylene oxide diamine are mixed in a reaction solvent and dehydrated and condensed. The reaction solvent is not particularly limited as long as it can dehydrate and condense diboronic acid in the presence of polyoxyalkylene diamine. Examples of the reaction solvent include 1,4-dioxane, mesitylene, tetrahydrofuran, tetrahydropyran, 1,3-dioxane and the like. Among these, a mixed solvent of 1,4-dioxane and mesitylene is preferable. As the mixing ratio of 1,4-dioxane and mesitylene in the mixed solvent, for example, the mixing ratio of 1,4-dioxane: mesitylene is preferably 25:75 to 75:25, more preferably 35:65 to 65:35. Preferably, 40:60 to 60:40 is more preferable, and 50:50 is particularly preferable.

Regarding the blending amount of diboronic acid and polyoxyalkylenediamine during dehydration condensation, from the viewpoint of improving ionic conductivity and lithium ion transport number and obtaining an electrolyte having excellent electrochemical characteristics, diboronic acid: polyoxyalkylenediamine The mass ratio is preferably 2: 1 to 4: 1, more preferably 2.5: 1.5 to 3.5: 1, and even more preferably 3: 1.

The reaction temperature at the time of dehydration condensation is not particularly limited as long as the boroxine compound can be obtained by dehydration condensation of diboronic acid. The reaction temperature is, for example, preferably 70 ° C. or higher and 150 ° C. or lower, more preferably 80 ° C. or higher and 140 ° C. or lower, and further preferably 90 ° C. or higher and 130 ° C. or lower. The reaction time for dehydration condensation is, for example, 10 minutes or more and 3 hours or less.

As described above, according to the above embodiment, since the boroxine ring of the boroxine compound formed by dehydration condensation of diboronic acid has electrophilicity, the anion coordination ability is improved and it becomes easier to capture anions. Ion conductivity and lithium ion transport number are improved. In addition, since the polyalkylenediamine intervenes between the boroxine compounds, an amino group is coordinated with the boroxine ring to improve the stability against hydrolysis between the boroxines. Further, as shown in FIGS. 2 and 3, a plurality of boroxine compounds (boroxine polymers) formed by dehydration condensation of a plurality of diboronic acids extend on a plane due to the presence of polyalkylene oxide diamine. Since a crosslink is formed between the boroxine rings of the boroxine compound of the above, it is possible to form a film while maintaining the excellent molecular motility of the polyalkylene oxide. Therefore, it is possible to realize a method for producing a supramolecular complex in which an electrolyte having excellent electrochemical properties can be obtained.

（上記式（３）中、Ｒ_５、Ｒ_６、Ｒ_７は、それぞれ独立して、２価の脂肪族基、２価の脂環族基、又は２価の芳香族基を表す。） (Supramolecular complex)
The supramolecular complex according to the present embodiment is obtained by the method for producing a supramolecular complex according to the above embodiment. The supramolecular complex is formed by interposing a polyalkylene oxide diamine between boroxine compounds containing a repeating structural unit represented by the following general formula (3). In this supramolecular complex, the polyalkylene oxide diamine is considered to have two amino groups coordinated to the boroxine ring of the boroxine compound.

(In the above formula (3), R ₅ , R ₆ and R ₇ each independently represent a divalent aliphatic group, a divalent alicyclic group, or a divalent aromatic group).

_{As R 5} , R ₆ and R ₇ of the general formula (3), the same ones as _{R 1} in the general formula (1) described above are used. Further, R ₅ , R ₆ and R ₇ may be the same or different from each other. Further, as the polyalkylene oxide diamine, the same one as described in the above-mentioned description of the method for producing a supramolecular complex can be used.

(Electrolytes)
The electrolyte according to the present embodiment is a gel-like solid electrolyte containing the supramolecular complex according to the above embodiment. This electrolyte is an organic electrolyte in which the supramolecular complex according to the above embodiment is mixed with a carbonate such as ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC), lithium hexafluorophosphate and the like. Obtained by impregnating the liquid. The concentration of the organic electrolyte is preferably 0.5 mol / L or more and 1.5 mol / L or less with respect to the electrolyte, for example. According to this electrolyte, since the boroxine ring of the boroxine compound formed by dehydration condensation of diboronic acid has electrophilicity, the anion coordination ability is improved, the anion is easily captured, and the lithium ion transport number is improved. In addition, since the polyalkylenediamine is interposed between the boroxine compounds, an amino group is coordinated with the boroxine ring to improve the stability against hydrolysis between the boroxines. Therefore, an electrolyte having excellent electrochemical characteristics can be realized.

Hereinafter, a more detailed description will be given based on an example carried out for clarifying the effect of the present invention. The present invention is not limited to the following examples and comparative examples.

(Example 1)
^{1.5 g (9.0 × 10 -3} mol) of 1,4-phenylenediboronic acid and polyalkylene oxide diamine (weight average molecular weight (Mw) = 2000 g) in a 200 mL flask so that the substance amount ratio is 3: 1. ^{After adding 6.0 g (3.0 × 10 -3} mol) of / mol, x + z = 6 and y = 39, trade name: Jeffamine (registered trademark), model number “ED-2003”, manufactured by Huntsman). , 1,4-dioxane (18 mL) and mecitylene (18 mL) were added, and the mixture was stirred at 120 ° C. for 1 hour to carry out a dehydration condensation reaction. Next, the obtained composition was dried, the obtained white solid was pulverized, washed with 500 ml of acetone, filtered and dried under reduced pressure at 60 ° C. for 24 hours, whereby the supramolecular shown in FIG. 2 was obtained. 4.6 g of a white powder of the complex was obtained.

FIG. 6 is a diagram showing the measurement results ^{of 11} B-NMR of the supramolecular complex obtained in Example 1. ^{The 11} B-NMR measurement results shown in FIG. 6 show that the supermolecular complex was dissolved in a solvent (deuterated methanol (CD ₃ OD, boron trifluoride (BF ₃ ) / diethyl ether complex) and then at 500 MHz. It was measured by a nuclear magnetic resonance apparatus (manufactured by JEOL Ltd.). As shown in FIG. 6, in the obtained supermolecular complex, the signal of 29 ppm based on the raw material 1,4-phenylenediboronic acid disappeared. , 26 ppm and 14 ppm new signals were generated.

FIG. 7 is a diagram showing the measurement results of the infrared absorption spectrum of the supramolecular complex obtained in Example 1. The infrared absorption spectrum shown in FIG. 7 is the result of measurement by a total reflection measurement method (ATR: Attenuated Total Reflection). As shown in FIG. 7, the supramolecular complex generated a new signal based on the BO bond in the region of ^{wave number 1347 cm -1.} From this result, it was confirmed that the supramolecular complex has a boroxine ring.

FIG. 8A is a scanning electron micrograph of the raw material 1,4-phenylenediboronic acid used in Example 1, and FIG. 8B is a dehydration condensate of 1,4-phenylenediboronic acid according to Example 1. FIG. 8C is a scanning electron micrograph of the supermolecular complex obtained in Example 1. As shown in FIGS. 8A to 8C, the supramolecular composites obtained in Example 1 are 1,4-phenylenediboronic acid having a crystal structure and 1,4-phenylenediboronic acid having an aggregated structure. Unlike the dehydrated condensate of acid (see FIG. 1), it had an amorphous structure without a crystal structure. From this result, it can be seen that the supramolecular complex obtained in Example 1 has a three-dimensional supramolecular structure.

Next, the supramolecular complex obtained in Example 1 was compression-molded into pellets, and the obtained pellets consisted of 1 mL of ethylene carbonate, 1 mL of ethyl methyl carbonate, 1 mL of dimethyl carbonate and 19.7 mg of lithium hexafluorophosphate. An electrolyte was prepared by impregnating with an organic electrolytic solution. The prepared electrolyte was evaluated for electrochemical performance of the prepared electrolyte by linear sweep voltammetry (LSV) and cyclic voltammetry (CV).

(LSV evaluation)
The LSV evaluation was carried out using a multipotentiometer / galvanostat (or electrochemical measuring device) (model number "VSP-300", manufactured by Biologic). Platinum was used as the working electrode, lithium metal was used as the reference electrode and the counter electrode, and the produced electrolyte was placed between the working electrode and the reference electrode and the counter electrode. Next, the redox potential was measured by sweeping the potential of the working electrode from 3 V to 6 V at a sweep rate of 10 mV / sec at 60 ° C. FIG. 9 is a diagram showing the result of the LSV evaluation of Example 1. As shown in FIG. 9, the electrolyte obtained in Example 1 has an oxidation initiation potential of 4.4 V with respect to a ^{current density of 0.1 mA / cm 2, and has excellent electrochemical stability.} Was.

(CV evaluation)
The CV evaluation was carried out using a multipotentiometer / galvanostat (or electrochemical measuring device) (model number "VSP-300", manufactured by Biologic). Nickel was used as the working electrode, lithium metal was used as the reference electrode and the counter electrode, and the produced electrolyte was placed between the working electrode and the reference electrode and the counter electrode. Next, the charge / discharge characteristics of the electrolyte were measured by repeatedly sweeping the potential of the working electrode between 1 V and −0.25 V at a sweep rate of 1 mV / sec at 60 ° C. for 10 cycles. FIG. 10 is a diagram showing the results of the CV evaluation of Example 1. As shown in FIG. 10, the electrolyte obtained in Example 1 is the third cycle (see broken line C3 in FIG. 10), the fifth cycle (see the alternate long and short dash line C5 in FIG. 10), and the seventh cycle (dotted line in FIG. 10). Stable oxidation-reduction of lithium ions was confirmed at both the C7) and the 10th cycle (see the dotted line C10 in FIG. 10).

(Example 2)
Example 1 except that lithium bis (trifluoromethylsulfonyl) amide (manufactured by Kanto Chemical Co., Inc.) was added to the supramolecular complex prepared in the same manner as in Example 1 without impregnation with the organic electrolytic solution. An electrolyte was prepared in the same manner as in the above. The ionic conductivity of the prepared electrolyte was measured to evaluate the electrochemical performance of the prepared electrolyte.

(Measurement of ionic conductivity)
Ion conductivity has a frequency range of 1 MHz to 100 MHz using a frequency response device (or impedance analyzer) (model number "SI1260", manufactured by Sollatron Analytical) and a constant temperature maintenance device (model number "SU-262", manufactured by ESPEC). , The measurement was performed under the condition that the applied voltage was 300 mV. As a result, the electrolyte produced in Example 2 has an ionic conductivity of 9.31 × ^10-6 Scm ^-1 at 25 ° C., and has excellent electrochemical characteristics as a solid electrolyte not impregnated with an organic electrolyte. Was found to have.

(CV evaluation)
The CV evaluation was carried out using a multipotentiometer / galvanostat (or electrochemical measuring device) (model number "VSP-300", manufactured by Biologic). Nickel was used as the working electrode, lithium metal was used as the reference electrode and the counter electrode, and the produced electrolyte was placed between the working electrode and the reference electrode and the counter electrode. Next, the charge / discharge characteristics of the electrolyte were measured by repeatedly sweeping the potential of the working electrode between 1 V and −0.25 V at a sweep rate of 1 mV / sec at 60 ° C. for 20 cycles. FIG. 11 is a diagram showing the results of the CV evaluation of Example 2. As shown in FIG. 11, in the electrolyte obtained in Example 2, stable redox of lithium ions was confirmed even at the 20th cycle (see the solid line C20 in FIG. 11).

As described above, according to the supramolecular composite according to the above-mentioned example, an electrolyte capable of excellent electrochemical stability and stable redox of lithium ions can be obtained, so that an electrolyte having excellent electrochemical characteristics can be obtained. It turned out to be. Further, according to the supermolecular composite according to the above-mentioned example, excellent electrochemical properties can be obtained not only in the gel-like solid electrolyte impregnated with the organic electrolytic solution but also in the solid electrolyte not impregnated with the organic electrolytic solution. It turned out to be.

11 Diboronic acid 12,121,122,123,124,125 Boroxine compound 12A Boroxine ring 13,131,132,133,134 Polyalkylene oxide diamine 20 Electrolyte 21 Anion 22 Lithium ion

Claims (8)

A method for producing a supramolecular complex, which comprises a step of dehydrating and condensing diboronic acid represented by the following general formula (1) in the presence of polyalkylene oxide diamine to obtain a supramolecular complex.

(In the above formula (1), R ₁ represents a divalent aliphatic group, a divalent alicyclic group, or a divalent aromatic group.) The super alkylene oxide diamine according to claim 1, wherein the polyalkylene oxide diamine is at least one selected from the group consisting of an ethylene oxide polymer, a propylene oxide polymer and an ethylene oxide propylene oxide copolymer having amino groups at both ends. Method for producing a molecular complex. The method for producing a supramolecular complex according to claim 1 or 2, wherein the polyalkylene oxide diamine is represented by the following general formula (2).

(In the above formula (2), R ₂ , R ₃ , and R ₄ independently represent a hydrogen atom or a hydrocarbon group having 1 or more and 10 or less carbon atoms. X and z are 1 or more and 100. The following integers. Y is an integer of 0 or more and 70 or less. X + z is an integer of 2 or more and 100 or less.) The method for producing a supramolecular complex according to any one of claims 1 to 3, wherein the diboronic acid is at least one selected from the group consisting of phenylenediboronic acid and phenylenediboronic acid derivatives. .. A supramolecular complex characterized in that a polyalkylene oxide diamine is interposed between boroxine compounds containing a repeating structural unit represented by the following general formula (3).

(In the above formula (3), R ₅ , R ₆ , and R ₇ represent a divalent aliphatic group, a divalent alicyclic group, or a divalent aromatic group.) The super alkylene oxide diamine according to claim 5, wherein the polyalkylene oxide diamine is at least one selected from the group consisting of an ethylene oxide polymer, a propylene oxide polymer and an ethylene oxide propylene oxide copolymer having amino groups at both ends. Molecular complex. The supramolecular complex according to claim 5 or 6, wherein the polyalkylene oxide diamine is represented by the following general formula (4).

(In the above formula (4) , R ₈ , R ₉ , and R ₁₀ each independently represent a hydrogen atom or a hydrocarbon group having 1 or more and 10 or less carbon atoms , and a and c are 1 or more and 100. The following integers. B is an integer of 0 or more and 70 or less. A + c is an integer of 2 or more and 100 or less.) An electrolyte comprising the supramolecular complex according to any one of claims 5 to 7.

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