JP2003068357A - Liquid crystal electrolyte and secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal electrolyte which has anisotropy in ionic conductivity and improved ionic conductivity in an electrolyte used in the filed of electronics such as a battery and a sensor device. SOLUTION: The electrolyte includes a liquid crystal compound, an organic boric acid compound and metal salt. The organic boric acid compound of higher Lewis acid is selectively coordinated to an anion through combination of the liquid crystal compound and the organic boric acid compound, and the ionic conductivity is improved by increasing the degree of dissociation of the metal salt. In addition, the anisotropy of the ionic conductivity can be improved by making use of the liquid crystal compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal electrolyte used in the field of electronics such as battery devices, photochromic devices and sensor devices, and a secondary battery using the same.

[0002]

BACKGROUND OF THE INVENTION Wright et al.
The ionic conduction property of a complex of polyethylene oxide (PEO) and an alkali metal salt was reported, Arma in 1979.
The fact that nd et al. have shown the possibility of electrolytes used in batteries has spread the research of solid electrolytes worldwide. Since the solid electrolyte is not a liquid in shape, it does not leak to the outside, and is advantageous over the liquid electrolyte in terms of heat resistance, reliability, safety, and device miniaturization. In addition, since organic substances are more flexible than inorganic substances, they have the advantage of being easy to process.

In general, the ionic conductivity of an electrolyte is represented by the product of carrier density, charge and ion mobility, so that a high polarity for dissociating ions and a low viscosity for moving dissociated ions are required. From that viewpoint, PEO cannot be said to have sufficient characteristics as a solid electrolyte. In the first place, the ion transport mechanism of PEO is based on ligand exchange in which ions dissociated by coordination with a donor polar group moiety are handed one after another by thermal segmental motion. Therefore, it is susceptible to temperature dependence. Further, if a large amount of metal ions are dissolved in order to increase the carrier density, crystallization will occur and conversely the ion mobility will decrease. In order to prevent this crystallization, PEO (M.W.
atanabe et al, “Solid Stat
e Ionics ", 28-30, 911, 198
8) Furthermore, PEO in which a side chain is introduced into the cross-linking portion in order to improve the ion mobility at low temperatures ("Proceedings of the 40th Symposium on Polymers", 3766, 1991) has been developed.
Recently, a molten salt type P with salt introduced at the end of PEO
EO (K. Ito et al., “Solid St.
ate Ionics ”, 86-88, 325, 199
6, K.I. Ito et al. , "Electoroc
him. Acta ", 42, 1561, 1997) has also been developed. However, at present, since an ionic conductivity is not sufficiently obtained, an electrolyte solution or an electrolyte solution in which a high dielectric constant organic solvent and a low viscosity solvent are mixed is used. The mainstream is gel electrolyte fixed with molecules.In addition, when a solid electrolyte is used as a battery device, it is desirable that only necessary ions, for example, lithium ions move in the case of a lithium battery. In this case, the anion species also move, which causes deterioration of cycle characteristics.
Further, not only the ion transport efficiency but also the efficiency of the electrochemical reaction at the contact surface with the electrode is a problem.

On the other hand, the discotic liquid crystal phase is 1977.
S. It is a liquid crystal phase discovered by Chandrasekhar et al. (“Pramana” 9 , 471 (1977)). For example, by the authors, Discotic
Under the title Liquid Crystals, "Rep.
log. Phys. 53 (1990) 57 or by Shunsuke Takenaka, entitled “Design and Synthesis of Discotic Liquid Crystal Molecules”, as described in the Chemical Society of Japan, Quarterly Chemistry Review, Vol. It is found in compounds in which a plurality of relatively long side chains are bound to the core of.

The kinds of the compounds can be classified mainly according to the structure of the core. Derivatives of 6-substituted benzene and 3-substituted benzene, derivatives of phthalocyanine and porphyrin, triphenylene, turksen and pyrylium derivatives, tribenzocyclononene derivative. , Azacrown derivatives, cyclohexane derivatives and the like. From the structural characteristics of discotic liquid crystals, several reports suggesting their application to devices have been made in the past. Application of electron (or hole) channels in systems with conjugated pi-electrons such as phthalocyanines and triphenylenes (Piechocki et al., "J. Am.
Chem. Soc. "1982, 104, pp524
5) In the case where the core has a ring shape such as an azacrown, an application of a molecular channel through which a molecule selectively passes through a central void portion (“J. Chem. Soc., Chem. Commu”).
n. , 1985, 1794, "J. Chem. So
c. Chem. Commun. ", 1995, 11
7, 9957).

In addition to being used as a display element of a liquid crystal display, smectic liquid crystals have been studied for application in various fields due to the functionality of liquid crystals. For example,
Application to optical switching element (M. Ozaki et al.
al, "Jpn. J. Appl. Phys.", 23,
ppL843, 1990), application to nonlinear optical elements (M. Ozaki et al, "Ferroelec").
trics ", 121, pp259, 1991), etc., and various smectic liquid crystal compounds have been synthesized accordingly.

As an application of the smectic liquid crystal to an electrolyte, a liquid crystal compound in which one ethylene oxide chain is introduced into a mesogen group (“J. Mater. Chem.”, 107).
9-1086,6 (7), 1996) and a dimer liquid crystal in which a mesogen group is introduced at both ends of an ethylene oxide chain ("Proceedings of the Liquid Crystal Society of Japan", 432, 1998).
, Etc. have been developed, but the ionic conductivity has not been sufficiently obtained. Further, in order to suppress the dendrite of the lithium negative electrode, it has been developed to add a smectic liquid crystal compound to the electrolytic solution (JP-A-10-112333). Regarding the electrolyte containing a borate ester, JP-A-2000-100469 and JP-A-2001-1557.
Known as 71 etc.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional techniques, and has anisotropy in ionic conductivity, and by containing an organic boric acid compound, ionic conductivity is improved. An object of the present invention is to provide an improved liquid crystal electrolyte and a secondary battery containing the same.

[0009]

That is, the present invention is a liquid crystal electrolyte containing a liquid crystal compound, an organic boric acid compound and a metal salt.

The liquid crystal compound is preferably a discotic liquid crystal compound. The liquid crystal compound is preferably a liquid crystal compound having at least a smectic phase. The liquid crystal compound is preferably polymerized by a polymerization reaction. The metal salt is preferably an alkali metal salt. The liquid crystal electrolyte preferably contains an organic solvent. The organic boric acid compound is preferably a borate ester.

The present invention is also a secondary battery using the above liquid crystal electrolyte.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The electrolyte of the present invention is characterized by containing a liquid crystal compound, an organic boric acid compound and a metal salt.

As the liquid crystal compound, a nematic liquid crystal compound represented by a rod-shaped liquid crystal, a smectic liquid crystal compound, and preferably a discotic liquid crystal compound having a columnar phase is used.

Further, it is preferable that these liquid crystal compounds are polymerized by polymerizing to fix the liquid crystal phase. In this case, a method of polymerizing a liquid crystal side chain having a polymerizable group such as an acrylic group, a methacrylic group, an epoxy group or a vinyl group, and a method of copolymerizing with another polymerizable compound are preferable. Other polymerizable compounds are not particularly limited, but include acrylic acid derivatives, methacrylic acid derivatives, vinyl derivatives,
Examples thereof include styrene derivatives, urethane derivatives and epoxy derivatives.

The content of the liquid crystal compound contained in the electrolyte of the present invention is usually 50 to 99% by weight, preferably 7%.
0 to 95% by weight is desirable. If it is less than 50% by weight, it is difficult to maintain the liquid crystallinity, and if it exceeds 99% by weight, the ionic conductivity is lowered, which is not preferable.

The organic boric acid compound is preferably an organic boric acid ester. Examples of the organic borate ester include alkyl borate ester, polyethylene borate ester,
Examples thereof include polypropylene borate ester and aromatic borate ester.

The content of the organic boric acid compound contained in the electrolyte of the present invention is preferably 1 in order to obtain the effects of the present invention.
˜50% by weight is desirable. Also, more preferably 5 to 3
0 wt% is desirable. If it is less than 1% by weight, the effect of the present invention is small, and if it exceeds 50% by weight, it becomes difficult to maintain liquid crystallinity, which is not preferable.

In the metal salt, MClO ₄ , MB
F ₄ , MPF ₆ , MCF ₃ SO ₃ (M is Li, Na, K
Indicates. ) Other than alkali metal salts such as CuSO ₄ , N
It preferably contains a metal salt such as i (NO ₃ ) ₂ or Ni (BF ₄ ) ₂ . Particularly preferably LiClO ₄ ,
LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , Li (C
It is a lithium metal salt such as F ₃ SO ₂ ) ₂ N. The content of the metal salt contained in the electrolyte of the present invention is usually 0.
01 to 50% by weight, preferably 0.1 to 30% by weight is desirable.

Further, the electrolyte of the present invention may contain an organic solvent. A polar organic solvent is preferable, and examples thereof include ethylene carbonate, propylene carbonate, γ-butyrolactone, tetrahydrofuran, dioxane, ethyl ethyl ketone, methyl propionate, dimethoxyethane, and glycols.

As described in the prior art, an electrolyte containing a boric acid ester in an organic solvent is known. However, in the present invention, an organic boric acid compound having a high Lewis acidity is obtained by combining a liquid crystal compound and an organic boric acid compound. Not only improves the ionic conductivity by selectively coordinating with anions and increasing the dissociation degree of the metal salt, but also improves the characteristic anisotropy of ionic conductivity by utilizing a liquid crystal electrolyte. It is a finding of what can be done.

The specific structures of the preferred organic boric acid compounds used in the present invention are shown below by the general formulas (a) to (a).
It shows with (d). However, the present invention is not limited to these.

[0022]

[Chemical 4]

(Wherein R _{21 to} R ₂₉ represent H or F, an alkyl group or an alkoxy group having 1 to 18 carbon atoms, (OCH ₂ CH ₂ ) _m OCH ₃ ; n is 1 to 18).
Indicates an integer up to. )

Next, the liquid crystal compound used in the present invention is
Preferred are compounds represented by the following general formulas (I) to (II).

[0025]

[Chemical 5]

In the general formula (I), R ₁ , R ₂ , R
₃ , R ₄ , R ₅ , and R ₆ are each independently two or more OCs.
A side chain composed of an H ₂ CH ₂ segment or an OCH ₂ CH ₂ CH ₂ segment and having a branched or straight-chain alkyl group having 1 to 20 carbon atoms at the terminal portion is shown. However, a hydrogen atom in the alkyl group may be replaced with a fluorine atom, and one or more methylene groups are -O-,
It may be replaced with -CO-, -CH = CH-, -C≡C- or an epoxy group.

In the above general formula (I), preferably R
₁ , R₂ , R₃ , R_Four , R_Five , R₆Each independently
(OCH₂CH₂)_n OR₈Or (OCH₂CH₂CH₂)
_n OR ₈Is. In the formula, n is an integer of 1 to 20 and R₈Is
Branched or straight-chain alkyl group having 4 to 20 carbon atoms
Indicates. The hydrogen atom in the alkyl group is placed at the fluorine atom.
It may be substituted, and one or more methylene groups are -O.
-, -CO-, -CH = CH-, -C≡C- or Epo
It may be replaced with a xy group.

[0028]

[Chemical 6]

In the general formula (II), A is A1-B1
-A2-B2-A3-B3-A4-B4-A5-B5-
A6 is shown. A1, A2 and A3 represent 1,4-phenylene (one or more CH may be replaced by CF or N) or 1,4-cyclohexylene. A4
A5 and A6 represent a single bond or 1,4-phenylene (one or more CH may be replaced by CF or N) or 1,4-cyclohexylene.

B1, B2, B3, B4 and B5 are single bonds or --CH ₂ O--, --OCH _2- , --COO--, --OOC.
-Indicates. X is -CH ₂ CH ₂ O- or -CHCH ₃ C
H ₂ O- are shown. Y represents -OCH ₂ CH ₂ - or -OCH ₂
CHCH ₃ − is shown.

R ₁₁ and R ₁₂ are each independently a linear or branched alkyl group having 1 to 100 carbon atoms, and at least one methylene in the alkyl group is —O—,
It may be replaced by -CO-, -S-, -CH = CH-, -C≡C- or an epoxy group. Further, the hydrogen atom in the alkyl group may be replaced with a fluorine atom.

M1 and n1 are integers from 3 to 25. It may be an optically active compound. Further, preferably, in the general formula (II), A of the compound is represented by the following general formula (IIa).
To (IIi).

In the formula, z each independently represents an integer of 0-4.

[0034]

[Chemical 7]

[0035]

[Chemical 8]

Specific structural formulas of liquid crystal compounds used in the electrolyte of the present invention are shown in Tables 1 to 14 below. However, the present invention is not limited to these. The abbreviations in the table indicate the following groups.

[0037]

[Chemical 9]

[0038]

[Chemical 10]

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

[Table 5]

[0044]

[Table 6]

[0045]

[Table 7]

[0046]

[Table 8]

[0047]

[Table 9]

[0048]

[Table 10]

[0049]

[Table 11]

[0050]

[Table 12]

[0051]

[Table 13]

[0052]

[Table 14]

Next, a secondary battery will be described as an application example of the electrolyte of the present invention. FIG. 1 is a schematic configuration example of a secondary battery. Reference numerals 11 and 12 are negative and positive electrodes, respectively. Reference numeral 13 is an electrolyte layer through which ions of a specific polarity are transferred from the negative electrode to the positive electrode or from the positive electrode to the negative electrode through the layer. Since the negative and positive electrodes are required to have a wide range of functions such as a function of releasing and absorbing ions, a function of cooperating with an external device (for example, an electronic conductivity function), and a mechanical supporting function, they are usually separated from each other. In many cases, it will be a composite composed of a plurality of members.

As the negative electrode 11, an electron conductive support 111 made of copper, aluminum, gold, platinum or the like which also has an electronic connection function with an external circuit is coated with a negative electrode active material 112. Alternatively, a negative electrode active material that also functions as a support can be used. As the negative electrode active material, as a material having the ability to release cations such as alkali ions such as Li ions, Na ions, and K ions, alkaline earth ions, and hydrogen ions, lithium metal foil, lithium-aluminum among metal materials can be used. Among the polymer materials, polyacetylene, polythiophene, polyp-phenylene, polyacene and the like and their derivatives which are preferably n-type doped among polymer materials, and among carbon materials, graphite (graphite), pitch, coke, A sintered body of an organic polymer or a composite of these materials and an organic polymer is selectively used as appropriate.

As the positive electrode 12, an electron conductive support 121 made of copper, aluminum, gold, platinum or the like, which also has an electronic connection function with an external circuit, is coated with a positive electrode active material 122. Alternatively, a positive electrode active material that also functions as a support can be used. As the positive electrode active material, among inorganic materials, chalcogen compounds and oxides of transition metals such as cobalt, vanadium, titanium, molybdenum, iron, and manganese, and a complex of these with lithium are used as carbon materials such as graphite and fluorine. A series of layered compounds such as carbonized carbon, or a composite of these materials and an organic polymer, which is preferably p-type or n-type doped from among polymer materials, is polyacetylene, polyaniline, polypyrrole, polythiophene, polyp-phenylene. , Polyacene, polyphthalocyanine, polypyridine and the like, and derivatives thereof are appropriately and selectively used.

[0056]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Synthesis Example 1 2,3,6,7,10,11-hexa (2-hexyloxyethyloxy) triphenylene (exemplified compound T-
6) Manufacturing

Production of 2-hexyloxyethyl p-toluenesulfonate 3.29 g of 2-hexyloxyethanol in a reaction vessel.
(22.5 mmol) and pyridine 5.33 g (67.5)
mmol), and 4.72 g (24.7 mmol) of p-toluenesulfonic acid chloride in an ice bath,
After stirring for 1 hour, the mixture was further stirred at room temperature for 3 hours. After the reaction was completed, 3N-HCl was added to acidify the mixture, and then 2 toluene was added.
Extracted twice. The extract was washed with water, dried over anhydrous sodium sulfate and dried. After the solvent was distilled off, the residue was purified by silica gel column chromatography (eluent: toluene / ethyl acetate = 10/1) and 2-hexyloxyethyl p-toluenesulfonate 6.45 g (21.5 mm)
ol) was obtained. 95% yield

Production of 2,3,6,7,10,11-hexa (2-hexyloxyethyloxy) triphenylene Dry N, N-dimethylformamide (DM
F) 15 ml and sodium hydride (60% in oi
1 (mineral oil)) 0.77 g (19.3 mmol),
Also, in a water bath, 0.93 g (2.84 mmo) of 2,3,6,7,10,11-hexahydroxytriphenylene
1) was added and stirred for 1 hour. Then, 6.3 g (21.0 m) of 2-hexyloxyethyl p-toluenesulfonate.
mol) and 5 ml of dry DMF were added dropwise, and the temperature was 80 ° C.
It was stirred for 5 hours. After completion of the reaction, add water and add 2 with toluene.
Extracted twice. The extract was washed with water, dried over anhydrous sodium sulfate and dried. After the solvent was distilled off, silica gel column chromatography (eluting solvent: toluene / ethyl acetate = 5/1) was performed twice for purification, and 2,3,6,7,1
0,11-hexa (2-hexyloxyethyloxy)
1.15 g (1.0 mmol) of triphenylene was obtained.
Yield 35%

The phase transition temperature of the obtained compound by DSC is shown below. Temperature rising process Cry (-24 ° C) Xl (17 ° C) X2 (29 ° C) Dh
(84 ° C) Iso Cooling process Iso (81 ° C) Dh (16 ° C) X2 (5 ° C) Xl (<
-50 ° C.) Cry Cry: crystalline phase, X1, X2: unidentified phase, Dh: discotic columnar phase, Iso: isotropic phase

Synthesis Example 2 4 '-[Methyloxytri (ethyleneoxy) ethyloxy] -4-biphenylcarboxylic acid 4- [methyloxytri (ethyleneoxy) ethyloxy] -4'-biphenyl (Exemplary Compound S-11) Manufacturing

Methyloxytri (ethyleneoxy)
Production of ethyloxytosylate In a 100 ml round-bottomed flask, tetraethylene glycol monomethyl ether 20 g (96 mmol) and pyridine 2 were added.
0 ml was charged and cooled to 0 ° C. in an ice bath. 23.8 g (125 mmol) of p-toluenesulfonic acid chloride was slowly added, and the mixture was stirred at 0 ° C for 12 hours. Water was added and extracted with chloroform. The organic layer was dried over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and the residue was separated and purified by silica gel chromatography (chloroform / methanol = 100/1) to give 34.5 g of methyloxydi (ethyleneoxy) ethyloxytosylate (95. 2 mmol, yield 99%) was obtained.

Production of 4 '-[methyloxytri (ethyleneoxy) ethyloxy] -4-biphenylcarboxylic acid In a 500 ml round bottom flask, 5 g (23 mmol) of 4'-hydroxy-4-biphenylcarboxylic acid, 3.3 g of potassium hydroxide, 400 ml of methanol was charged and the mixture was heated under reflux for 1 hour. Methyloxytri (ethyleneoxy)
8.5 g (23 mmol) of ethyl oxytosylate was added, and the mixture was heated under reflux for 24 hours. The reaction solution was cooled to room temperature, neutralized with 1N hydrochloric acid, water was added, and the mixture was extracted with chloroform. After drying the organic layer with anhydrous sodium sulfate,
The solvent was distilled off under reduced pressure, and the residue was separated and purified by silica gel chromatography (chloroform / methanol = 30/1),
White solid 4 '-[Methyloxytri (ethyleneoxy)
Ethyloxy] -4-biphenylcarboxylic acid 3.8 g
(9.4 mmol, yield 40%) was obtained.

Preparation of 4 '-[methyloxytri (ethyleneoxy) ethyloxy] -4-hydroxybiphenyl 4,4'-biphenol in a 500 ml round bottom flask.
6 g (14 mmol), 1.8 g of potassium hydroxide and 250 ml of methanol were charged and the mixture was heated under reflux for 1 hour.
5.1 g (14 mmol) of methyloxytri (ethyleneoxy) ethyloxytosylate was added, and the mixture was further heated under reflux for 24 hours. The reaction solution was cooled to room temperature, neutralized with 1N hydrochloric acid, water was added, and the mixture was extracted with chloroform. The organic layer was dried over anhydrous sodium sulfate, the solvent was evaporated under reduced pressure, and the residue was separated and purified by silica gel chromatography (chloroform / methanol = 50/1) to give a white solid 4′-
[Methyloxytri (ethyleneoxy) ethyloxy]
1.8 g of 4-hydroxybiphenyl (4.7 mmo
l, yield 33.6%).

4 ′-[methyloxytri (ethyleneoxy) ethyloxy] -4-biphenylcarboxylic acid 4
Production of-[methyloxytri (ethyleneoxy) ethyloxy] -4'-biphenyl (Exemplary Compound S-11) 4 '-[methyloxytri (ethyleneoxy) ethyloxy] -4-biphenylcarboxylic acid 2 g ( 5.0 mmol), 4 '-[methyloxytri (ethyleneoxy) ethyloxy] -4-hydroxybiphenyl 1.9 g (5.0 mmol), 1,3-
Dicyclocarbodiimide 0.8 g (10 mmol), 4
-Dimethylaminopyridine (0.6 g, 5 mmol) and dry chloroform (20 ml) were charged, and the mixture was stirred at room temperature for 24 hours.

After completion of the reaction, water was added and the mixture was extracted with chloroform. The organic layer was dried over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and the residue was separated and purified by silica gel chromatography (chloroform / methanol = 30/1) and then recrystallized (acetone) to give a white solid 4 '-[methyl]. Oxytri (ethyleneoxy) ethyloxy] -4-biphenylcarboxylic acid 4- [methyloxytri (ethyleneoxy)
Ethyloxy] -4'-biphenyl 2.9 g (3.8 m
mol, yield 75.2%) was obtained.

The phase transition temperatures are shown below. Temperature rising process Cry (51 ° C) SmX (104 ° C) SmC (154
℃) N (173 ℃) Iso Cooling process Iso (170 ℃) N (150 ℃) SmC (99 ℃) S
mX (9 ° C.) CryCry: crystalline phase, SmX: higher order smectic phase, SmC: smectic C phase, N: nematic phase, Iso: isotropic phase

Example 1 Next, 2, 3, 6, 7, 10, 11- synthesized in Synthesis Example 1
To 65.6 mg (0.06 mmol) of hexa (2-hexyloxyethyloxy) triphenylene was added 1 ml of dry dichloromethane, and the mixture was stirred and completely dissolved. And tris (methyloxytri (ethyleneoxy) ethyl)
Borate ester 19.0 mg, lithium perchlorate 3.1
9 mg (0.030 mmol) and dry ethanol 1 ml
Was added and stirred for 2 hours. After confirming that it was completely dissolved, the solvent was distilled off and the residue was dried under reduced pressure to obtain an electrolyte A.
The obtained electrolyte A showed a discotic liquid crystal phase at room temperature.

Next, an IT with a thickness of 700 Å is used as a transparent electrode.
A pair of glass substrates having an O film and having a thickness of 1.1 mm were prepared. On the transparent electrode of the substrate, silica beads having an average particle diameter of 2.4 μm were scattered as a spacer on one substrate to prepare a cell A having a uniform cell gap. The electrolyte A prepared in Example 1 was injected into this cell in an isotropic liquid state, and cooled from the isotropic phase to a temperature showing a discotic columnar phase at 20 ° C./h. When the texture of this cell was observed with a polarizing microscope under crossed Nicols, a dark field was obtained, and it was found that the discotic columnar phase had homeotropic orientation.

Next, 0.001 to 100 kHz, 10 mV
The current when the AC voltage was applied was measured to measure the complex impedance, and the ionic conductivity was calculated. The results are shown below.

Measurement temperature Ionic conductivity 40 ° C. 3.1 × 10 ⁻⁷ S / cm

Next, a cell B was prepared by the same method except that silica beads having an average particle size of 20 μm were used in place of the silica beads having an average particle size of 2.4 μm, electrolyte A was injected, and a texture was obtained by a polarizing microscope. As a result, multidomain orientation was observed, and it was found that the discotic columnar phase was randomly oriented.

Further, the complex impedance was measured by the same method, and the ionic conductivity was calculated. The results are shown below. Measurement temperature Ionic conductivity 40 ° C 5.6 × 10 ^-9 S / cm

EXAMPLE 2 2,3,6,7,10,11-hexa (2-hexyloxyethyloxy) triphenylene 65.6 mg (0.
(06 mmol) was added with 1 ml of dry dichloromethane and stirred to completely dissolve it. And 4-fluoro-2- (4
-Fluorophenyl) benzo [1,3,2] dioxaborol 7.0 mg, lithium perchlorate 3.19 mg
(0.030 mmol) and 1 ml of dry ethanol were added and stirred for 2 hours. After confirming that it was completely dissolved, the solvent was distilled off and the residue was dried under reduced pressure to obtain an electrolyte B. The obtained electrolyte B showed a discotic liquid crystal phase at room temperature.

Next, two types of cells were prepared and injected by the same method as in Example 1 except that the electrolyte B was used in place of the electrolyte A, and the texture was observed with a polarizing microscope.
It was found that the cell A made of silica beads having an average particle diameter of 2.4 μm as a spacer provided a dark field, and the discotic columnar phase had homeotropic orientation. It was found that the cell B made of silica beads having an average particle size of 20 μm had a multi-domain orientation, and the discotic columnar phase had a random orientation.

The complex impedance was measured by the same method as in Example 1 to calculate the ionic conductivity. The results are shown below. Average particle size 2.4 μm Silica bead cell measurement temperature Ionic conductivity 40 ° C. 1.4 × 10 ⁻⁷ S / cm Average particle size 20 μm silica bead cell measurement temperature Ionic conductivity 40 ° C. 9.8 × 10 ⁻⁹ S / cm

Comparative Example 1 2,3,6,7,10,11-hexa (2-hexyloxyethyloxy) triphenylene 65.6 mg (0.
(06 mmol) was added with 1 ml of dry dichloromethane and stirred to completely dissolve it. Lithium perchlorate 3.1
9 mg (0.030 mmol) and dry ethanol 1 ml
Was added and stirred for 2 hours. After confirming that the solvent was completely dissolved, the solvent was distilled off and the residue was dried under reduced pressure to obtain an electrolyte C.
The obtained electrolyte C was the same as that of Example 1 except that the electrolyte C was used instead of the electrolyte A that exhibited a discotic liquid crystal phase at room temperature.
When two types of cells were prepared and injected by the same method as above, and the texture was observed with a polarizing microscope, cell A prepared with 2.4 μm silica beads as a spacer gave a dark field and had a discotic columnar phase. It was found that they had homeotropic alignment, but it was found that the cell B made of 20 μm silica beads had multi-domain alignment and the discotic columnar phase had random alignment. The complex impedance was measured by the same method as in Example 1 to calculate the ionic conductivity.

The results are shown below. Average particle size 2.4 μm Silica bead cell measurement temperature Ionic conductivity 40 ° C. 7.9 × 10 ⁻⁹ S / cm Average particle size 20 μm silica bead cell measurement temperature Ionic conductivity 40 ° C. 8.8 × 10 ⁻¹⁰ S / cm

Example 3 37.0 m of the exemplified compound (S-11) synthesized in Synthesis Example 2
1 g of dry dichloromethane was added to g (0.05 mmol) and stirred to completely dissolve it. Tris (methyloxytri (ethyleneoxy) ethyl) borate 19.0 mg, lithium trifluoromethanesulfonate 3.6 mg (0.023 mmol) and dry THF 1 ml.
Was added and stirred for 2 hours. After confirming that the solvent was completely dissolved, the solvent was distilled off and the residue was dried under reduced pressure to obtain an electrolyte D.
The obtained electrolyte D had a liquid crystal phase.

Next, two glass plates were prepared, a gold film having a thickness of 400 Å was formed on one glass plate, and etching was performed in the pattern shown in FIG. Polyimide resin precursor [SP-710 manufactured by Toray Industries, Inc.] on each glass plate
2000% rotation of 1.5% dimethylacetamide solution
r. p. m. Was applied for 15 seconds with the spinner of. After film formation,
A heat condensation baking treatment was performed at 300 ° C. for 60 minutes. At this time, the film thickness of the coating film was about 250Å. After the baking, the coating film is rubbed with an acetate flocked cloth, washed with an isopropyl alcohol solution, and silica beads having an average particle size of 2.0 μm are sprinkled on one of the glass plates. Are parallel to each other, and the glass plates are stuck together using an adhesive sealant [Mitsui Toatsu Co., Ltd. Structbond] for 60 minutes, 170
A cell C was prepared by heating and drying at ℃.

Electrolyte D was injected into this cell C in an isotropic liquid state, and cooled from the isotropic phase to a temperature showing a smectic A phase at 3 ° C./min. When the texture of this cell was observed with a polarizing microscope under crossed Nicols, smectic A
A homogeneous homogeneous orientation of the phases was observed.

Next, 0.001 to 100 kHz, 3000
The ionic conductivity was calculated by measuring the current when an alternating voltage of mV was applied to measure the complex impedance. The results are shown below.

Measurement temperature in X direction Ionic conductivity 40 ° C. 9.2 × 10 ⁻⁷ S / cm Measurement temperature in Y direction Ionic conductivity 40 ° C. 9.5 × 10 ⁻⁴ S / cm

Comparative Example 2 Production of Electrolyte E Exemplified Compound (S-11) 50 mg (0.066 mmo)
4 ml of dry chloroform was added to 1) and stirred to completely dissolve it. TH in which 4.09 mg (0.026 mmol) of lithium trifluoromethanesulfonate was dissolved
1 ml of F solution was added and stirred for 2 hours. The solvent was slowly distilled off under reduced pressure and then dried under reduced pressure to obtain an electrolyte E. The obtained electrolyte E had a liquid crystal phase.

Two types of cells were prepared and injected by the same method as in Example 3 except that the electrolyte E was used in place of the electrolyte D, and the complex impedance was measured by the same method as in Example 3 to determine the ionic conductivity. It was calculated.

The results are shown below. X-direction measurement temperature Ionic conductivity 40 ° C. 5.2 × 10 ⁻⁷ S / cm Y-direction measurement temperature Ionic conductivity 40 ° C. 3.2 × 10 ⁻⁵ S / cm

Comparing the electrolytes A and B of Examples 1 and 2 with the electrolyte C of Comparative Example 1 and the electrolyte D of Example 3 and the electrolyte E of Comparative Example 2, the electrolytes A, B and D of the present invention were It can be seen that the value of ionic conductivity is large and the ionic conductivity is anisotropic.

[0088]

As described above, according to the present invention, there is provided a liquid crystal electrolyte having an anisotropic ionic conductivity and an improved ionic conductivity in an electrolyte used in the electronics field such as a battery and a sensor device. Can be done.

The present invention can also provide a secondary battery using the above-mentioned electrolyte having anisotropic ionic conductivity.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a secondary battery.

FIG. 2 is a pattern diagram of cell C.

[Explanation of symbols]

11 Negative electrode 111 Electronically conductive support 112 Negative electrode active material 12 Positive electrode 121 Electronically conductive support 122 Positive electrode active material 13 Electrolyte layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07F 5/04 C07F 5/04 C F term (reference) 4H006 AA01 AB64 BJ50 BP10 BP30 GP01 GP03 4H048 AA01 AB64 VA75 VA77 5H029 AJ00 AK02 AK03 AK05 AK07 AK16 AL06 AL07 AL12 AL16 AM00 AM03 AM04 AM07 DJ11 EJ11 HJ02

Claims (10)

[Claims] 1. A liquid crystal electrolyte containing a liquid crystal compound, an organic boric acid compound, and a metal salt. 2. The liquid crystal electrolyte according to claim 1, wherein the liquid crystal compound is a discotic liquid crystal compound. 3. The liquid crystal electrolyte according to claim 1, wherein the liquid crystal compound is a liquid crystal compound having at least a smectic phase. 4. The liquid crystal electrolyte according to claim 1, wherein the liquid crystal compound is a liquid crystal compound represented by the following general formula (I) or (II). [Chemical 1] (In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ are each independently two or more OCH ₂ CH ₂ segments or OCH ₂
A side chain composed of a CH ₂ CH ₂ segment and having a branched or straight-chain alkyl group having 1 to 20 carbon atoms at the terminal portion is shown. However, a hydrogen atom in the alkyl group may be replaced with a fluorine atom, and one or more methylene groups are -O-, -CO-, -CH = CH-, -C≡C.
-Or may be replaced by an epoxy group). [Chemical 2] (In the formula, A is A1-B1-A2-B2-A3-B3-A
4-B4-A5-B5-A6 is shown. A1, A2, A3
Is 1,4-phenylene (one or more CH is CF or N
Or 1,4-cyclohexylene. A4, A5 and A6 are single bonds or 1,4
Represents phenylene (one or more CH may be replaced by CF or N) or 1,4-cyclohexylene. B1, B2, B3, B4 and B5 are single bonds or-
_{CH 2 O -, - OCH 2} -, - COO -, - OOC- shows a. X is -CH ₂ CH ₂ O- or -CHCH ₃ CH ₂ O-
Indicates. Y represents -OCH ₂ CH ₂ - or -OCH ₂ CHC
H ₃ − is shown. R ₁₁ and R ₁₂ are each independently a linear or branched alkyl group having 1 to 100 carbon atoms, and at least one methylene in the alkyl group is —O.
It may be replaced with-, -CO-, -S-, -CH = CH-, -C≡C- or an epoxy group. Further, the hydrogen atom in the alkyl group may be replaced with a fluorine atom. m1 and n1 represent integers from 3 to 25. It may be an optically active compound. ) 5. The liquid crystal compound has the following structural formula (III):
The liquid crystal electrolyte according to claim 1, which is a liquid crystal compound represented by (IV). [Chemical 3] 6. The liquid crystal electrolyte according to claim 1, wherein the liquid crystal compound is polymerized by a polymerization reaction. 7. The liquid crystal electrolyte according to claim 1, wherein the metal salt is an alkali metal salt. 8. The liquid crystal electrolyte according to claim 1, which contains an organic solvent. 9. The liquid crystal electrolyte according to claim 1, wherein the organic boric acid compound is a boric acid ester. 10. A secondary battery using the liquid crystal electrolyte according to any one of claims 1 to 9.