JP2007210971A - Liquid complex compound, electrolyte containing the liquid complex compound, and electrochemical device having the electrolyte - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid complex compound which has good designability and high polarity, because of not having a free ion originated from a matrix, and is useful as a reaction solvent or an electrolyte, to provide an electrolyte which contains the liquid complex compound and exhibits an excellent ion conductive characteristic, and to provide an electrochemical device has the electrolyte and has an excellent electric characteristic. <P>SOLUTION: This liquid complex compound is characterized by having a boron alkylate-nitrogen-containing heterocyclic complex structure in which the boron alkylate and the nitrogen-containing heterocyclic group coexist. An electrolyte comprising an ionic compound and the liquid complex compound has excellent ion conductivity. An electrochemical device having the electrolyte can be used as one of various kinds of batteries, an electric double layer capacitor, or the like. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid complex compound, an electrolyte containing the liquid complex compound, and an electrochemical device including the electrolyte. More specifically, a liquid complex compound having excellent polarity while maintaining liquid physical properties and having excellent ion conductivity when used with an ionic compound, an electrolyte containing the liquid complex compound and having excellent ion conductivity, And an electrochemical device including the electrolyte and having excellent electrical characteristics.

  In recent years, research has been conducted on ionic liquids used as reaction solvents and electrolytes having high design properties, and further improvements in various properties have been demanded. An ionic liquid is a non-flammable, non-volatile, clean solvent that can be reused, and has high electrochemical stability and excellent ionic conductivity even when used as an electrolyte. is there. Such ionic liquids have been studied for use in various electrochemical devices such as various batteries such as lithium batteries and fuel cells, electrochromic displays, dye-sensitized solar cells, and electric double layer capacitors.

  In addition, in batteries and the like, not only high ion conductivity but also selective transport of target ions having reactivity with electrodes is important for improving characteristics. In the case of a general ionic liquid, the lithium ion transport number is 0.2 to 0.3 at room temperature like many aprotic polar solvents, and the mobility of lithium ions to anions is low. In the case of an ionic liquid, the matrix itself is composed of ions. However, in such a configuration, the constituent ions are considered to move along the potential gradient in the electrolyte. This is not easy to transport. Furthermore, when an electrolyte having such an ionic liquid is used in an electrochemical device such as a battery, there has also been a problem that polarization occurs inside the electrolyte during charging and discharging.

  On the other hand, as a means for solving such a problem, a zwitterionic molten salt in which ion migration derived from a matrix is suppressed by binding a cation and an anion with a covalent bond can be mentioned. An organic boron molten salt in which a Lewis acidic organic boron unit is introduced as an anion receptor is also a material with improved cation transport number (for example, Patent Document 1 to Patent Document 8 and Non-Patent Document 1 to Non-Patent Document 3). reference.).

JP-A-4-349365 Japanese Patent Laid-Open No. 10-92467 JP 11-86905 A JP 11-260400 A JP 2002-110230 A JP 2004-263004 A JP 2004-161615 A JP 2005-228588 A Yoshizawa (M), Hirao (Mira), Ito (Ito-Akita, K), Ohno (H), “Journal of Material Chemistry” (UK), 2001 Year, Volume 11, p. 1057 Matsumi (N), Mizumo, T, Ohno, H, “Polymer Bulletin” (Germany), 2004, Vol. 51, p.389. Matsumi (N), Miyake (Miyake, M), Ohno (H), "Chemical. Communications" (UK), 2004, p. 2852

  However, although the above-described prior art has improved the cation transport number, a significant amount of matrix-derived anion migration has been required. In addition, in such a prior art, the system in which the matrix maintains the liquid physical properties is very limited. Therefore, like an ionic liquid, the development of an electrolytic solution excellent in design property in which the matrix maintains liquid properties and essentially does not contain ions in the matrix is expected.

  The present invention has been made in view of the above problems, and in addition to exhibiting stable liquid physical properties at room temperature, since it does not have free ions derived from the matrix, it has good design and high polarity, and has a reaction. To provide a liquid complex compound useful as a solvent or an electrolytic solution, an electrolyte containing the liquid complex compound and exhibiting excellent ion conductivity, and an electrochemical device having the electrolyte and having excellent electrical characteristics. It is in.

  In order to achieve the above object, the liquid complex compound of the present invention is characterized in that an alkylated boron and a nitrogen-containing heterocycle coexist.

  In the liquid complex compound of the present invention, the alkylated boron and the nitrogen-containing heterocycle coexist, whereby the nitrogen atom of the nitrogen-containing heterocycle is coordinated to the boron atom of the alkylated boron, and the alkylated boron-nitrogen-containing heterocycle Form a composite structure. That is, in the liquid complex compound according to the present invention, an alkylated boron and a nitrogen-containing heterocycle coexist and an alkylated boron-nitrogen-containing heterocyclic complex structure is formed, so that charges are generated on both boron and nitrogen atoms. Therefore, it is possible to provide high polarity without having free ions derived from the matrix while maintaining the liquid physical properties, and the design as a solution is also good. Therefore, when applied to various organic compounds and ionic compounds, the effect of increasing the solubility is obtained, and when used together with the ionic compound, the effect of increasing the dissociation can be achieved. It becomes an electrolytic solution or a reaction solvent that can constitute an electrolyte having high ionic conductivity.

  In the liquid complex compound of the present invention, the nitrogen-containing heterocycle is preferably one selected from the group consisting of an imidazole ring, a pyridine ring, and derivatives thereof. According to such a configuration, an imidazole ring, a pyridine ring, or the like is employed as the nitrogen-containing heterocycle described above, and these have a composite structure with an alkylated boron, so that the charges are stable on both boron and nitrogen atoms. Thus, a high polarity can be obtained, and a liquid complex compound in which no ions that can move alone in the matrix are present, and the above-described effects can be efficiently achieved.

  The liquid complex compound of the present invention preferably has a molecular structure represented by the following formula (I).

（式（Ｉ）中、３つのＲ_１のうち少なくとも１つはアルキル基、残りはアルキル基または水素原子であり、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５はそれぞれ水素原子または１価の基、を示す。）

(In formula (I), at least one of the three R ₁ is an alkyl group, the rest is an alkyl group or a hydrogen atom, and R ₂ , R ₃ , R ₄ and R ₅ are each a hydrogen atom or a monovalent group. )

  According to such a configuration, the compound according to the present invention, as represented by the formula (I), has an alkylated boron-imidazole composite structure, thereby improving the dissociation property of the ionic compound used therewith. And a liquid complex compound capable of constituting an electrolyte having high ionic conductivity.

  The liquid complex compound according to the present invention preferably has a molecular structure represented by the following formula (II).

（式（II）中、３つのＲ_１のうち少なくとも１つはアルキル基、残りはアルキル基または水素原子であり、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５、Ｒ_６はそれぞれ水素原子または１価の基、を示す。）

(In the formula (II), at least one of the three R ₁ is an alkyl group, the rest is an alkyl group or a hydrogen atom, and R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are each a hydrogen atom or 1 Valent group.)

  According to such a configuration, as represented by the formula (II), the compound according to the present invention has an alkylated boron-pyridinium composite structure, thereby further improving the dissociation property of the ionic compound used therewith. An effect is obtained and it becomes a liquid complex compound which can constitute an electrolyte having high ionic conductivity.

In the liquid complex compound of the present invention, it is preferable that all of R ₁ are alkyl groups.
According to the present invention, by all alkyl groups R ₁ in formula (I) or Formula (II), the alkyl boron becomes trialkyl borane, activation energy during transport compound carrier ions It becomes a small, low-viscosity liquid complex compound.

  The electrolyte of the present invention is characterized by containing an ionic compound and the above-described liquid complex compound of the present invention. Since the electrolyte of the present invention contains the liquid complex compound of the present invention having high polarity, the dissociation property is enhanced by using it together with the ionic compound, and the electrolyte has high ionic conductivity.

  Moreover, the electrochemical device of the present invention includes the above-described electrolyte of the present invention. Since the electrochemical device according to the present invention includes the electrolyte of the present invention having high ionic conductivity, the electrochemical device has excellent electrical characteristics.

  According to the liquid complex compound of the present invention, by taking an alkylated boron-nitrogen-containing heterocyclic complex structure, it is possible to express high polarity while maintaining liquid properties with low viscosity, so that the design as a solution is also good. There is provided an electrolytic solution or a reaction solvent that can constitute an electrolyte having high ionic conductivity. Moreover, the electrolyte of the present invention containing such a liquid complex compound is an electrolyte that exhibits high ionic conductivity and excellent in ionic conductivity. The electrochemical device of the present invention provided with the electrolyte has excellent electrical characteristics, such as various batteries such as a lithium primary battery, a lithium secondary battery, a lithium ion battery, a fuel cell, and a solar cell, It can be applied to a multilayer capacitor or the like.

The present invention is a liquid complex compound in which an alkylated boron-nitrogen-containing heterocyclic complex structure is formed by allowing a nitrogen-containing heterocyclic ring to coexist with an alkylated boron.
First, boron, monoalkylated boron, dialkylated boron, and trialkylated boron can be applied as the alkylated boron constituting the liquid complex compound of the present invention, but the liquid complex compound of the present invention is a carrier ion. A low-viscosity system having a small activation energy during transportation is preferred. From this viewpoint, trialkylated boron (trialkylborane) is preferred.

  Examples of the group other than the alkyl group in the alkylated boron include, for example, a hydrogen atom, aryl group, allyl group, benzyl group, alkenyl group, alkynyl group, alkyl ether group, alkyl ester group, alkyl ketone group, heterocyclic group, or these groups. Derivatives (hereinafter also referred to as “hydrogen atom etc.”). These may have not only a straight chain structure but also a side chain, and may further have a cyclic structure.

Examples of the alkyl group include a methyl group (CH ₃ —), an ethyl group (CH ₃ CH ₂ —), a propyl group (CH ₃ CH ₂ CH ₂ —), an isopropyl group ((CH ₃ ) ₂ CH—), and butyl. group _{(CH 3 CH 2 CH 2 CH} 2 -), an isobutyl group _{((CH 3) 2 CHCH 2} -), s- butyl group _{(CH 3 CH 2 CH (CH} 3) -), t- butyl ((CH ₃ ) ₃ C-), phenyl group (C ₆ H _5- ) and the like.

  Examples of the nitrogen-containing heterocycle coexisting with the alkylated boron constituting the liquid complex compound of the present invention include, for example, an imidazole ring, a pyridine ring, a pyrrolidine ring, a piperidine ring, a pyrroline ring, a pyrrole ring, a pyrazole ring, and an indole ring. , A carbazole ring, and derivatives thereof. Among these nitrogen-containing heterocycles, it is preferable to have an imidazole ring, a pyridine ring, or a derivative thereof. By adopting these as nitrogen-containing heterocycles, a stable charge is generated on both boron and nitrogen atoms. Thus, a high polarity is obtained, and a liquid complex compound in which ions that can move alone in the matrix do not exist is obtained.

  Furthermore, the liquid complex compound of the present invention preferably has a structure represented by formula (I) or formula (II) as its molecular structure. In the case of forming an electrolyte with an ionic compound by having an alkylated boron-imidazole composite structure represented by formula (I) or an alkylated boron-pyridinium composite structure represented by formula (II) Provides an effect of increasing the dissociation property of the ionic compound used together, and becomes a liquid complex compound that can constitute an electrolyte having high ionic conductivity. Moreover, since the imidazole compound and pyridine compound for forming an imidazole ring or a pyridine ring can be obtained at low cost, the liquid complex compound of the present invention can be provided at low cost.

In the structures represented by formula (I) and formula (II), at least one of the three R ₁ is an alkyl group, the rest is an alkyl group or a hydrogen atom, and is preferably an alkyl group or a hydrogen atom. . On the other hand, as described above, the liquid complex compound of the present invention is preferably a low-viscosity system having a small activation energy when transporting carrier ions, and from this point of view, all three R ₁ are all alkyl groups. Particularly preferred.

Further, _R 2 to R ₅ in formula (I), _R 2 ~R ₆ in formula (II) are each hydrogen atom or a monovalent group, the monovalent group include an alkyl group, an aryl group , Allyl group, alkenyl group, vinyl group, alkynyl group, alkyl ether group, alkyl ester group, alkyl ketone group, cyano group, hydroxyl group, formyl group, aryloxy group, alkylthio group, arylthio group, acyloxy group, sulfonyloxy group Amino group, alkylamino group, arylamino group, carboxylicamino group, oxysulfonylamino group, sulfonamido group, oxycarbonylamino group, acyl group, oxycarbonyl group, carbamoyl group, sulfonyl group, sulfinyl group, oxysulfonyl group, Sulfamoyl group, carboxylic acid group, sulfonic acid group, ben Group, phosphonic acid group, a heterocyclic group, and derivatives thereof. These may have not only a linear structure but also a side chain, and may further have a cyclic structure.

Hereinafter, preferred examples of the structure represented by the formula (I) are shown. Formula (III) is a compound in which three R ₁ and R ₃ are alkyl groups and R ₂ , R ₄ , and R ₅ are hydrogen atoms in Formula (I). In I), three R ₁ are alkyl groups, R ₃ is an allyl group, and R ₂ , R ₄ , and R ₅ are hydrogen atoms. Note that m and n are positive integers.

  Here, in the structures represented by the formulas (III) and (IV), when m is an integer of 16 or more, the resulting liquid complex compound has high viscosity and low polarity, and is used as a solvent, an electrolyte solution or an electrolyte. Therefore, m is preferably 15 or less.

  Further, in the structure represented by the formula (III), when n is an integer of 5 or more, the polarity of the generated compound decreases, and the dissociation property of the ionic compound used for the electrolyte containing the liquid complex compound of the present invention. N is preferably 4 or less because the effect of increasing the pH cannot be sufficiently obtained, and also when used as a solvent, the ability to dissolve various substrates decreases.

  Below, the preferable specific example of the structure represented by Formula (III) and Formula (IV) is illustrated as Formula (V) and Formula (VI).

Similarly, preferred examples of the structure represented by formula (II) are shown. In the formula (VII), three R ₁ and R ₄ in the formula (II) are alkyl groups, R ₂ , R ₃ , R ₅ and R ₆ are hydrogen atoms, and the formula (VIII) is In the formula (II), three R ₁ are alkyl groups, R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are hydrogen atoms, and the formula (IX) R ₁ is an alkyl group, R ₄ is a vinyl group, and R ₂ , R ₃ , R _5, and R ₆ are hydrogen atoms. Note that m and n are positive integers.

  Here, in the structure represented by formula (VII), formula (VIII), or formula (IX), when m is an integer of 16 or more, the resulting liquid complex compound has high viscosity and low polarity, Alternatively, m is preferably 15 or less because sufficient performance as an electrolyte or electrolyte cannot be obtained.

  Further, in the structure represented by the formula (VII), when n is an integer of 4 or more, the polarity of the generated compound decreases, and the dissociation property of the ionic compound used for the electrolyte containing the liquid complex compound of the present invention. N is preferably 3 or less because the effect of increasing the pH cannot be sufficiently obtained, and also when used as a solvent, the dissolving ability of various substrates decreases.

Below, the preferable specific example of the structure represented by Formula (IX) is illustrated as Formula (X).

Below, the preferable manufacturing method of the liquid complex compound which concerns on embodiment of this invention is illustrated and demonstrated.
As shown in the following scheme, the alkylated boron represented by the formula (X) is reacted with a nitrogen-containing heterocyclic compound such as imidazoles represented by the formula (Y) to form the formula (I ′). A liquid complex compound according to an embodiment of the present invention is obtained. In the formula (I ′), n is a positive integer as in the above formula (III), and n is preferably 4 or less.

  Here, as the alkylated boron represented by the formula (X), for example, triethylborane, tributylborane and the like can be preferably exemplified. Moreover, as imidazole represented by Formula (Y), for example, imidazole, 1-methylimidazole, 1-ethylimidazole and the like can be preferably exemplified, and commercial products such as those manufactured by Tokyo Chemical Industry Co., Ltd. are used. can do.

  As mentioned above, although the preferable example of the liquid complex compound which concerns on embodiment of this invention which has a structure represented by Formula (I) was demonstrated, the liquid which concerns on embodiment of this invention which has a structure represented by Formula (II) The complex compound can be produced in the same manner. That is, as shown in the following scheme, the alkylated boron represented by the formula (X) is reacted with the nitrogen-containing heterocyclic compound of the pyridine ring represented by the formula (Z) to thereby obtain the formula (II ′ The liquid complex compound according to the embodiment of the present invention represented by formula (I) is obtained in the same manner as in the formula (I ′). Here, as a pyridine compound represented by a formula (Z), a pyridine can be mentioned, for example, and commercial items, such as the Tokyo Chemical Industry Co., Ltd. product, can be used. In the formula (II ′), n is a positive integer like the above formula (VII), and n is preferably 3 or less.

  In the liquid complex compound of the present invention, the alkylated boron and the nitrogen-containing heterocyclic ring coexist, the nitrogen atom of the nitrogen-containing heterocyclic ring is coordinated to the boron atom of the alkylated boron, and the alkylated boron-nitrogen-containing heterocyclic complex structure By forming a charge on both boron and nitrogen atoms, it can have high polarity while maintaining liquid properties without having free ions derived from the matrix, and design as a solution The property is also good. Therefore, when applied to various organic compounds and ionic compounds, the effect of increasing the solubility is obtained. For example, when used together with the ionic compound, the high ion having the effect of increasing the dissociation property is obtained. It becomes an electrolytic solution or a reaction solvent that can constitute an electrolyte having conductivity.

  Moreover, the electrolyte of this invention is comprised by containing an ionic compound and the above-mentioned liquid complex compound of this invention. Since the electrolyte having such a configuration contains the liquid complex compound of the present invention having excellent polarity, the electrolyte has high ionic conductivity. Since the electrolyte of the present invention provides carrier ions, an ionic compound composed of such carrier ions can be obtained by coexisting with the liquid complex compound of the present invention. Although there is no restriction | limiting in particular, What is necessary is just to contain as an active ingredient, and if it considers a viscosity and polarity, what is necessary is just about 0.1-10 mol / liter, for example, but it is not limited to this range.

Examples of ionic compounds composed of carrier ions include LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiSCN, LiBr, LiI, Li ₂ SO ₄ , Li ₂ B ₁₀ Cl ₁₀ , LiAlCl ₄ , LiSbF ₆ , Inorganic ion salts containing one of lithium (Li), sodium (Na), or potassium (K) such as LiCl, NaClO ₄ , NaI, NaSCN, NaBr, KClO ₄ , and KSCN can be given.
In addition, LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) ₃ and organic ion salts containing lithium such as LiC (C ₂ F ₅ SO ₂ ) ₃ .
Furthermore, (CH ₃ ) ₄ NBF ₄ , (CH ₃ ) ₄ NBr, (CH ₃ ) ₄ N (CF ₃ SO ₂ ) ₂ N, (CH ₃ ) ₄ N (C ₂ F ₅ SO ₂ ) ₂ N, (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NClO ₄ , (C ₂ H ₅ ) ₄ NI, (C ₂ H ₅ ) ₄ N (CF ₃ SO ₂ ) ₂ N, (C ₂ H _{5) 4 n (C 2 F} 5 SO 2) 2 n, (C 3 H 7) 4 NBr, (n-C 4 H 9) 4 NBF 4, (n-C 4 H 9) 4 n (CF 3 SO _{2) 2 n, (n-} C 4 H 9) 4N (C 2 F 5 SO 2) 2 n, (n-C 4 H 9) 4 NClO 4, (n-C 4 H 9) 4 NI, (C _{2 H 5) 4 N-maleate} , (C 2 H 5) 4 N-benzoate, (C 2 H 5) quaternary ammonium such as 4N-phtalate Umm salts and the like. These ionic compounds can be used alone or in combination of two or more.

  The electrolyte according to the present invention may be an organic solvent such as propylene carbonate, polyethylene oxide, dimethoxyethane, 1-ethyl-3methylimidazole-bistrifluoromethylsulfonylimide (TFSI) or 1- 1 An ionic liquid such as ethyl-3methylimidazole-tetrafluoroborate may be added as long as the effects of the present invention are not hindered.

  There are no particular restrictions on the preparation of the electrolyte of the present invention. For example, the liquid complex compound of the present invention and an ionic compound are mixed in a solvent such as tetrahydrofuran under a nitrogen atmosphere by means such as stirring, and then mixed. It can be easily obtained by removing the solvent and drying.

  Moreover, the electrochemical device of the present invention is characterized by comprising the electrolyte of the present invention. Since such an electrochemical device includes the electrolyte of the present invention having excellent ionic conductivity, an electrochemical device having excellent electrical characteristics can be obtained. Here, examples of the electrochemical device include various batteries such as a lithium primary battery, a lithium secondary battery, a lithium ion battery, a fuel battery, and a solar battery, and an electric double layer capacitor.

FIG. 1 is a cross-sectional view showing an example of the configuration of a lithium secondary battery 1 which is an embodiment of the electrochemical device of the present invention. Various batteries represented by such lithium secondary batteries include a positive electrode, a negative electrode, and the electrolyte of the present invention.
A lithium secondary battery 1 shown in FIG. 1 includes a positive electrode current collector 12 with a positive electrode terminal (not shown), a positive electrode 13 in contact therewith, a negative electrode current collector 14 with a negative electrode terminal (not shown), and a negative electrode in contact therewith. 15, an electrolyte 11 sandwiched between the positive electrode 13 and the negative electrode 15, and a container 18 for storing them.

  Here, examples of the positive electrode active material of the positive electrode 13 include transition metal oxides such as lithium manganate, lithium nickelate, and lithium cobaltate, and conventionally known conductive polymers such as polyacetylene, polyphenylene, polyaniline, and polypyrrole. Used. On the other hand, as the negative electrode active material of the negative electrode 15, for example, conventionally known materials such as a carbon material capable of storing lithium ions, lithium metal, a lithium alloy, and a conductive polymer are used. As the positive electrode current collector 12 and the negative electrode current collector 14, for example, conventionally known materials such as metals such as aluminum and copper, and carbon materials are used.

  In the case where the electrolyte 11 is a lithium secondary battery as shown in FIG. 1, the electrolyte 11 preferably has lithium ions as carrier ions, so that the liquid complex compound according to the present invention, It is preferable to apply an ionic compound having lithium ions. Moreover, as the container 18, conventionally well-known things, such as a metal case, a resin case, a resin film, are used, for example.

  Next, FIG. 2 is a cross-sectional view showing an example of the configuration of an electric double layer capacitor 2 which is another aspect of the electrochemical device of the present invention. The electric double layer capacitor 2 includes a separator 21 made of the electrolyte of the present invention and a polarizable electrode 22 disposed so as to face the separator 21 and, in addition, a gasket 23 that holds the separator 21 and the polarizable electrode 22 from the side. And a pair of current collectors 24 in contact with the polarizable electrode 22 as a basic configuration.

  As the polarizable electrode 22, for example, activated carbon or a material obtained by impregnating activated carbon into a solidified binder with an electrolytic solution is used. As the gasket 23, for example, a conventionally known constituent material such as a resin material is used. As the current collector 24, for example, a conventionally known one such as a conductive resin imparted with conductivity by carbon powder or the like can be used.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiments or examples are merely examples in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention. Further, although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

For example, as an example of an electrochemical device, the configuration of the lithium secondary battery 1 is shown in FIG. 1 and the configuration of the electric double layer capacitor 2 is shown in FIG. It is not limited.
In addition, the specific structure, shape, and the like in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not restrict | limited at all by these Examples.

[Example 1]
(Preparation of liquid complex compound A)
In a nitrogen atmosphere at room temperature, 0.961 g of 1-ethylimidazole was added to 10 ml of tetrahydrofuran solution as 1.0 M tributylborane and a solvent, and the reaction solution was stirred for 2 hours. Thereafter, the solvent was distilled off and dried under reduced pressure to obtain 2.76 g of 1-ethylimidazole-tributylborane complex (yield 99%). This is designated as Compound A of the present invention. The measurement results of ¹ H-NMR and ¹¹ B-NMR are shown below. In addition, FIG. 3 shows a chart of ¹ H-NMR, and FIG. 4 shows a chart of ¹¹ B-NMR.

(Measurement results of ¹ H-NMR and ¹¹ B-NMR)
¹ H-NMR (solvent: CDCl ₃ , δ (ppm): 0.87, 1.30, 1.46, 4.01, 6.91, 7.09, 7.63)
¹¹ B-NMR (solvent: CDCl ₃ , δ (ppm): −11.9)

[Example 2]
(Preparation of liquid complex compound B)
In a nitrogen atmosphere at room temperature, 1.08 g of 1-allylimidazole was added to 10 ml of a tetrahydrofuran solution as 1.0 M tributylborane and a solvent, and the reaction solution was stirred for 2 hours. Then, the solvent was distilled off and dried under reduced pressure to obtain 2.84 g of 1-allylimidazole-tributylborane complex (yield 98%). This is designated as Compound B of the present invention. The measurement results of ¹ H-NMR and ¹¹ B-NMR are shown below. In addition, FIG. 5 shows a chart of ¹ H-NMR, and FIG. 6 shows a chart of ¹¹ B-NMR.

(Measurement results of ¹ H-NMR and ¹¹ B-NMR)
¹ H-NMR (solvent: CDCl ₃ , δ (ppm): 0.80, 1.27, 4.56, 5.19 to 5.31, 5.94, 6.89, 7.10, 7.61 )
¹¹ B-NMR (solvent: CDCl ₃ , δ (ppm): −11.6)

[Example 3]
(Preparation of liquid complex compound C)
In a nitrogen atmosphere at room temperature, 0.681 g of imidazole was added to 10 ml of a tetrahydrofuran solution as 1.0 M tributylborane and a solvent, and the reaction solution was stirred for 2 hours. Then, the solvent was distilled off and dried under reduced pressure to obtain 2.40 g of imidazole-tributylborane complex (yield 98%). This is designated as Compound C of the present invention. The measurement results of ¹ H-NMR and ¹¹ B-NMR are shown below. In addition, FIG. 7 shows a chart of ¹ H-NMR, and FIG. 8 shows a chart of ¹¹ B-NMR.

(Measurement results of ¹ H-NMR and ¹¹ B-NMR)
¹ H-NMR (solvent: CD ₃ OD, δ (ppm): 0.60, 1.15, 1.89, 6.89, 7.84)
¹¹ B-NMR (solvent: CD ₃ OD, δ (ppm): −21.6, −18.3)

[Test Example 1]
(Viscosity measurement)
About this invention compound A, B, and C, the viscosity was measured according to JISZ8803. Table 1 shows the viscosity of each compound at 25 ° C.

(Measurement result)

  As shown in Table 1, the viscosities of the compounds A to C of the present invention at 25 ° C. were 36 cP, 28 cP, and 109 cP, respectively. These values are comparable to viscosities (43 to 45 cP) such as 1-ethyl-3methylimidazole-bistrifluoromethylsulfonylimide (TFSI), which is a typical ionic liquid, and are suitable for reaction solvents and electrolytes. The viscosity is sufficiently low even if the use of is considered.

[Test Example 2]
(Polarity evaluation)
The polarities of the compounds A to C of the present invention were evaluated using a Reichard dye. Table 2 shows the polar parameter E _T (30) value calculated from the absorption maximum wavelength of the Reichard dye measured for each compound.

(Measurement result)

As shown in Table 2, the values of the polarity parameter E _T (30) were as high as 44, 43 and 60 for the compounds A, B and C of the present invention, respectively. The polarities of the compounds A and B of the present invention were approximately the same as the polar parameter values (40 to 45) of acetone and acetonitrile, which are aprotic polar solvents.

[Example 4]
(Preparation of electrolyte A)
In 10 ml of tetrahydrofuran as a solvent, 2 ml of the compound A of the present invention and 0.0574 g of LiN (CF ₃ SO ₂ ) _{2 as} an ionic compound were mixed in a nitrogen atmosphere at room temperature and stirred for 1 hour. Was removed and vacuum-dried for 24 hours to obtain an electrolyte A of the present invention.

[Example 5]
(Preparation of electrolyte B)
In 10 ml of tetrahydrofuran as a solvent, 2 ml of the compound A of the present invention and 0.144 g of LiN (CF ₃ SO ₂ ) _{2 as} an ionic compound were mixed in a nitrogen atmosphere at room temperature and stirred for 1 hour. Was removed and vacuum-dried for 24 hours to obtain an electrolyte B of the present invention.

[Example 6]
(Preparation of electrolyte C)
In 10 ml of tetrahydrofuran as a solvent, 2 ml of the compound A of the present invention and 0.287 g of LiN (CF ₃ SO ₂ ) _{2 as} an ionic compound were mixed in a nitrogen atmosphere at room temperature and stirred for 1 hour. Was removed and vacuum-dried for 24 hours to obtain an electrolyte C of the present invention.

[Example 7]
(Preparation of electrolyte D)
In 10 ml of tetrahydrofuran as a solvent, 2 ml of the compound A of the present invention and 0.574 g of LiN (CF ₃ SO ₂ ) _{2 as} an ionic compound were mixed in a nitrogen atmosphere at room temperature and stirred for 1 hour. Was removed and vacuum-dried for 24 hours to obtain an electrolyte D of the present invention.

[Example 8]
(Preparation of electrolyte E)
In 10 ml of tetrahydrofuran as a solvent, 2 ml of the compound B of the present invention and 0.0574 g of LiN (CF ₃ SO ₂ ) _{2 as} an ionic compound were mixed in a nitrogen atmosphere at room temperature and stirred for 1 hour. Was removed and vacuum-dried for 24 hours to obtain an electrolyte E of the present invention.

[Example 9]
(Preparation of electrolyte F)
In 10 ml of tetrahydrofuran as a solvent, 2 ml of the compound B of the present invention and 0.144 g of LiN (CF ₃ SO ₂ ) _{2 as} an ionic compound were mixed in a nitrogen atmosphere at room temperature and stirred for 1 hour. Was removed and vacuum-dried for 24 hours to obtain an electrolyte F of the present invention.

[Example 10]
(Preparation of electrolyte G)
In 10 ml of tetrahydrofuran as a solvent, 2 ml of the compound B of the present invention and 0.287 g of LiN (CF ₃ SO ₂ ) _{2 as} an ionic compound were mixed in a nitrogen atmosphere at room temperature and stirred for 1 hour. Was removed and vacuum-dried for 24 hours to obtain an electrolyte G of the present invention.

[Example 11]
(Preparation of electrolyte H)
In 10 ml of tetrahydrofuran as a solvent, 2 ml of the compound B of the present invention and 0.574 g of LiN (CF ₃ SO ₂ ) _{2 as} an ionic compound were mixed in a nitrogen atmosphere at room temperature and stirred for 1 hour. Was removed and vacuum-dried for 24 hours to obtain the electrolyte H of the present invention.

[Test Example 3]
(Ion conductivity measurement)
Using the electrolytes A to H of the present invention prepared in Examples 4 to 11, two-terminal cells were produced as electrochemical devices. The configuration of the two-terminal cell 5 is shown as a cross-sectional view in FIG. The two-terminal cell 5 is configured by laminating two electrodes 51 and 52 by a conventionally known hot press so as to sandwich the electrolyte 11, and stainless steel is used as one electrode 51 and the other electrode 52 in this test. .

  Using this two-terminal cell 5, ion conductivity was measured as electrochemical characteristics of these electrolytes. Ionic conductivity was measured by the AC impedance method. Table 3 shows the ionic conductivity measured at 50 ° C.

(Measurement result)

  As shown in Table 3, the electrolytes A to H of the present invention show good ionic conductivity in a wide range of salt concentrations, and do not contain ions derived from the electrolyte, and can be expected as electrolytes suitable for more selective ion transport. Met.

  As can be seen from this result, the polarity and viscosity as a solvent are controlled by selecting a substituent on boron or a nitrogen-containing heterocycle, and preferably the ionic conductivity is considered by simultaneously considering the cation transport number. Can be further improved. As described above, the liquid complex compound according to the present invention has high polarity and low viscosity, and when an electrolyte is formed together with an ionic compound, the liquid complex compound is an electrolyte having high ionic conductivity and excellent electrical characteristics. It was confirmed that a chemical device could be provided.

  The liquid complex compound according to the present invention can be widely applied as an electrolyte for electrochemical devices such as lithium primary batteries, lithium secondary batteries, lithium ion batteries, electric double layer capacitors, and fuel cells, in addition to reaction solvents. Moreover, the electrochemical device excellent in electrical characteristics, such as charging / discharging performance and charging / discharging cycling performance, can be provided by using the electrolyte concerning this invention for these electrochemical devices.

It is sectional drawing which showed an example of the structure of the lithium secondary battery which is one aspect | mode of the electrochemical device of this invention. It is sectional drawing which showed an example of the structure of the electrical double layer capacitor which is an aspect of the electrochemical device of this invention. 1 is a diagram showing a ¹ H-NMR chart of the compound A of the present invention obtained in Example 1. FIG. 1 is a diagram showing an ¹¹ B-NMR chart of the compound A of the present invention obtained in Example 1. FIG. 3 is a diagram showing a ¹ H-NMR chart of the compound B of the present invention obtained in Example 2. FIG. 4 is a diagram showing an ¹¹ B-NMR chart of the compound B of the present invention obtained in Example 2. FIG. 3 is a diagram showing a ¹ H-NMR chart of the compound C of the present invention obtained in Example 3. FIG. 4 is a diagram showing an ¹¹ B-NMR chart of the compound C of the present invention obtained in Example 3. FIG. 6 is a cross-sectional view showing a configuration of a two-terminal cell used in Test Example 3. FIG.

Explanation of symbols

1 Lithium secondary battery (electrochemical device)
2 Electric double layer capacitor (electrochemical device)
5 Two-terminal cell 11 Electrolyte 12 Positive electrode current collector 13 Positive electrode 14 Negative electrode current collector 15 Negative electrode 18 Container 21 Separator (electrolyte)
22 Polarized electrode 23 Gasket 24 Current collector 51 Electrode 52 Electrode

Claims (7)

  A liquid complex compound in which an alkylated boron and a nitrogen-containing heterocycle coexist.   The liquid complex compound according to claim 1, wherein the nitrogen-containing heterocycle is one selected from the group consisting of an imidazole ring, a pyridine ring, and derivatives thereof. The liquid complex compound according to claim 1 or 2, which has a molecular structure represented by the following formula (I).

(In formula (I), at least one of the three R ₁ is an alkyl group, the rest is an alkyl group or a hydrogen atom, and R ₂ , R ₃ , R ₄ and R ₅ are each a hydrogen atom or a monovalent group. ) The liquid complex compound according to claim 1 or 2, which has a molecular structure represented by the following formula (II).

(In the formula (II), at least one of the three R ₁ is an alkyl group, the rest is an alkyl group or a hydrogen atom, and R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are each a hydrogen atom or 1 Valent group.) The liquid complex compound according to claim 3 or 4, wherein all of R ₁ are alkyl groups.   An electrolyte comprising an ionic compound and the liquid complex compound according to any one of claims 1 to 5. An electrochemical device comprising the electrolyte according to claim 6.

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