JP4896497B2 - Liquid crystalline compound and ionic conductor using the same - Google Patents

Description

  The present invention relates to a liquid crystal compound and an ionic conductor using the same. More specifically, the present invention relates to an ion conductor having characteristics suitable for various devices such as lithium and lithium ion batteries, capacitors, photoelectrochemical cells, ion sensors, photochromic elements, and fuel cells.

  Conventionally known ion conductors include inorganic solid electrolytes using inorganic materials, polymer solid electrolytes using organic polymers, and liquid electrolytes using water or non-aqueous solvents. The polymer solid electrolyte is non-volatile without risk of liquid leakage, and has attracted attention as an electrolyte for next-generation lithium secondary batteries. However, the solid polymer electrolyte is not sufficiently high in ionic conductivity at this stage.

  In order to improve the ionic conductivity, a gel electrolyte obtained by solidifying a liquid electrolyte with a gelling agent has been studied. However, since a liquid component that easily volatilizes remains in the gel electrolyte, the safety of the device cannot be sufficiently ensured.

In recent years, an ionic conductor using a liquid crystalline compound having an intermediate property between a solid and a liquid and utilizing the orientation of the liquid crystalline compound has been proposed (Patent Documents 1 to 3).
JP 2001-338527 A JP 2002-105033 A JP 2002-358821 A

  Considering the conditions for practical use, it is desirable that the ionic conductor disposed between the electrodes exhibits high ionic conductivity in the direction between the electrodes at room temperature. However, conventional liquid crystal compounds are not suitable for obtaining such characteristics. For example, the liquid crystalline compounds disclosed in Patent Documents 2 and 3 have a smectic liquid crystal phase in which each compound (molecule) is aligned perpendicular to the surface of the electrode. In the smectic liquid crystal phase, an effective ion path is used. Is formed parallel to the surface of the electrodes, the ion conductivity in the direction between the electrodes is not sufficiently high. Further, for example, the liquid crystalline compound disclosed in Patent Document 1 has a discotic liquid crystal phase in which an ion path is formed in a direction perpendicular to the surface of the electrode. Ionic conductivity should not be high.

  Therefore, the present invention provides a liquid crystal compound represented by the following general formula.

However, n is an integer of 1 to 5, R ₁ is a CN group or F, R ₂ is an alkyl group or an alkyloxy group having 5 to 10 carbon atoms, X is none or a COO group, Y is an alkyl group having 1 to 5 carbon atoms. When X is “none”, the liquid crystalline compound has a structure in which three benzene rings are continuously bonded. R ₂ and Y are preferably straight chain alkyl (oxy) groups. Incidentally, according to conventional, has been simplified description above general formula, the repeating unit n is attached at the side chain, an oxyethylene unit (OCH ₂ CH _2).

  The present invention further provides an ionic conductor containing the liquid crystalline compound and an electrolyte.

  When the liquid crystalline compound according to the present invention is used, it is possible to provide an ionic conductor having high ionic conductivity in the direction between the electrodes arranged to face each other. The ionic conductor according to the present invention exhibits good ionic conductivity in the direction between the electrodes at room temperature.

  The liquid crystalline compound represented by the above general formula has a mesogenic group containing three benzene rings. And the ionic conductor containing this liquid crystalline compound shows high ionic conductivity in the direction between the electrodes when the mesogenic group is aligned perpendicular to the surface of the electrodes. This is because when the mesogenic group is oriented perpendicular to the surface of the electrode, the side chain containing oxyethylene units gathers in a region extending along the direction between the electrodes, and this region becomes an ion path. .

  In addition to the liquid crystal compound (A) represented by the above general formula (Formula 1), the ionic conductor according to the present invention further includes a liquid crystal compound (B) which is a different liquid crystal compound and exhibits a nematic liquid crystal phase. It should be included. This is because it becomes easy to align the liquid crystalline compound constituting the ionic conductor in the direction between the electrodes.

  The liquid crystal compound (B) may be represented by any one selected from the following general formulas (Chemical Formula 2) to (Chemical Formula 6). These liquid crystalline compounds have the property of being aligned perpendicular to an electrode substrate typified by a glass electrode on which an ITO (indium tin oxide) film is formed.

However, R ₀ is a linear alkyl group having 2 to 8 carbon atoms, and R _{3 to} R ₆ are linear alkyl groups having 2 to 10 carbon atoms.

  Two or more liquid crystalline compounds (B) may be included. This is because the temperature range showing the liquid crystal phase can be expanded. Note that in this specification, even if they can be represented by the same general formula, they are treated as not being the same compound as long as the carbon number of the linear alkyl group is different.

  In addition to the liquid crystalline compound (B), the ionic conductor of the present invention may contain a liquid crystalline compound represented by any one selected from the following general formulas (Chemical Formula 7) to (Chemical Formula 11). This is because the temperature range showing the liquid crystal phase can be extended to the high temperature side.

R ₇ and R ₈ are straight chain alkyl groups having 3 to 6 carbon atoms, R ₉ is an ethyl group, R ₁₀ is an ethyl group or a propyl group, and R ₁₁ is a hexyl group. is there.

  In the ionic conductor of the present invention, the molar ratio of the liquid crystal compound (A) to the liquid crystal compound (B) is preferably 5:95 to 50:50. Moreover, it is good to make the content rate of the electrolyte with respect to the whole liquid crystalline compound into 1-30 mol%. When the electrolyte is insufficient, the ions necessary for the expression of conductivity are insufficient, and when the electrolyte is excessive, the expression of the liquid crystal phase is inhibited and it may be difficult to obtain high ionic conductivity.

  The ionic conductor of the present invention may further contain an oligomer. If the ion conductor is added with an oligomer, the ion conductivity may be further improved. Examples of oligomers include ethylene oxide oligomers, propylene oxide oligomers, and siloxane oligomers containing oxyethylene units in the side chain. An oligomer refers to a polymer having a low degree of polymerization, specifically a polymer having a degree of polymerization in the range of 2-20. As the oligomer added to the ionic conductor, a nonvolatile oligomer is preferable.

  In order to improve the ionic conductivity, it is preferable to add an ethylene oxide oligomer as the oligomer. Ethylene oxide oligomers having various molecular weights and end groups are commercially available, and those having 10 or less oxyethylene units may be selected. This is because if the number of oxyethylene units exceeds 10, phase separation tends to occur between the liquid crystalline compounds and it becomes difficult to obtain a uniform electrolyte. On the other hand, when the number of oxyethylene units is 2 or less, the oligomer becomes volatile. Considering the above, 3 to 10 is preferable as the oxyethylene unit. The ethylene oxide oligomer preferably has a methoxy group at its end.

  The oligomer such as ethylene oxide oligomer may be added so as to occupy 20 mol% or less, for example, 3 to 15 mol% of the entire ion conductor. If the ratio of the oligomer is too high, phase separation may occur. If the ratio of the oligomer is too low, the effect of improving the ionic conductivity by adding the oligomer cannot be obtained sufficiently.

As the electrolyte, alkali metal salts, are particularly suitable lithium salt, _{specifically, LiPF 6, LiBF 4, LiN} (C 2 F 5 SO 2) 2, LiAsF 6, LiSbF 6, LiAlF 4, LiGaF 4, LiInF ₄ , LiClO ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiCF ₃ SO ₃ , LiSiF ₆ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) or the like can be used.

The electrolyte may be appropriately selected according to the device. As an electrolyte other than lithium salt, LiI, NaI, KI, CsI, metal iodide such as CaI _2, iodine salt of a quaternary imidazolium compound, an iodine tetraalkylammonium compounds Motoshio, LiBr, NaBr, KBr, CsBr, CaBr Examples thereof include metal bromides such as ₂ .

  Another preferred example of the electrolyte is a protonic acid. The proton acid may be an inorganic acid or an organic acid. Inorganic acids include nitric acid, sulfuric acid, sulfurous acid, bisulfite, phosphoric acid, phosphorous acid, hypophosphoric acid, metaphosphoric acid, hypophosphorous acid, amidophosphoric acid, carbonic acid, bicarbonate, hydrochloric acid, hydrobromic acid, hydroiodic acid, orthoboron. Examples thereof include acid, metaboric acid, aluminate, amidosulfuric acid, hydrazinosulfuric acid and sulfamic acid. Organic acids include isovaleric acid, isobutyric acid, octanoic acid, cyclohexanecarboxylic acid, lactic acid, acetic acid, butyric acid, crotonic acid, azelaic acid, citric acid, succinic acid, oxalic acid, tartaric acid, fumaric acid, malonic acid, Malic acid, lauric acid, myristic acid, palmitic acid, stearic acid, anisic acid, benzoic acid, p-aminobenzoic acid, naphthoic acid, terephthalic acid, pyromellitic acid, asparagine, aspartic acid, 4-aminobutyric acid, alanine, arginine , Isoleucine, glycine, glutamic acid, cysteine, serine, valine, histidine, methionine, leucine, benzoic acid, benzoic acid-2-phosphate, adenosine-2'-phosphate, phenol-3-phosphate, galactose-1-phosphate, benzenephosphone Acid, 2-aminoethylphosphonic acid, 2-bromo-p-tri Phosphonic acid, 2-methoxyphenylphosphonic acid, t-butylphosphinic acid, o-cresol, m-cresol, p-cresol, 4-amino-m-cresol, 2,4-dinitrophenol, o-bromophenol, p- Phenolsulfonic acid, p-acetylphenol, ascorbic acid, reductin, 3-hydroxyphenylboric acid, 3-aminophenylboric acid, β-phenylethylboronic acid, hydrazine-N, N-diacetic acid, hydrazine-N, N ′ -Diacetate can be exemplified. The proton acid is not limited to the above, and may be, for example, sulfonylimide acid, a derivative thereof, or the like.

  The ionic conductor of the present invention may contain a gelling agent and other components in addition to the liquid crystalline compound and the electrolyte, but the content of other components is preferably 20 mol% or less.

  The ion conductor of the present invention is easily vertically aligned with respect to a substrate, particularly an electrode substrate such as a glass electrode on which an ITO film is formed. However, if it is necessary to improve the vertical alignment, a vertical alignment agent such as lecithin or hexadecylamine may be added. The electric field or magnetic field may be applied between the electrode substrates to enhance the vertical alignment of the liquid crystalline compound.

  The ion conductor of the present invention can be applied to various devices such as lithium ion batteries and fuel cells. For example, in a dye-sensitized solar cell, a nonvolatile ion conductor is required, but the ion conductor of the present invention sufficiently satisfies the required characteristics.

Hereinafter, the present invention will be described more specifically with reference to examples. First, a method for measuring ion conductivity will be described.
(Measurement method of vertical ionic conductivity)
FIG. 1 shows a cell used for measurement of ionic conductivity. In order to produce this cell, first, in the argon glove box, a sample filling unit 1 is placed on a glass plate 4 (a glass electrode with an ITO film) 4 mm in length and 10 mm in which an ITO film 3 is previously formed as a transparent conductive film. As a spacer 2, a polyimide film with an adhesive (see FIG. 2) having a thickness of 25 μm obtained by punching a circle having a diameter (r) of 6 mm was attached. Next, the sample filling portion 1 is filled with a sample (ion conductor) heated to an isotropic liquid state, and then the ITO film 3 is connected to the filling portion 1 side of another glass electrode 4 with an ITO film. Arranged to be.

  The vertical ion conductivity measurement cell thus obtained was naturally cooled to room temperature (23 ° C), and using an impedance measurement device (Yokogawa Hewlett Packard 4284A), the complex impedance method was used to determine the high frequency arc and low frequency. The real component impedance at the intersection with the straight line on the side was determined, and the conductivity σ (S / cm) was calculated based on the following equation.

σ _v = d / (R × A)
d: spacer thickness (cm), R: real component impedance (Ω), A: electrode plate area (cm ² )

(Measurement method of ionic conductivity in the horizontal direction)
FIG. 3 shows the comb-shaped electrode used for the measurement of horizontal ionic conductivity. The comb-shaped electrode 11 was formed by vapor-depositing ITO on a glass plate so as to have a thickness of 30 nm and further depositing an alloy composed of Ag and Au so that the total thickness becomes 0.8 μm. The comb electrodes 11 arranged so as to face each other have three comb portions 12, each comb portion 12 has a width W of 2 mm, a distance D between the comb portions 12 is 3 mm, and an overlapping width V of the facing comb portions is 7 mm. . A sample to be measured is heated between the comb portions 12 of the comb-shaped electrode 11 so as to be in an isotropic state and then applied, and a glass plate having a length of 10 mm and a width of 25 mm is overlapped on a region covering the sample. The sample was held only in this region (measurement region 13). Thereafter, the conductivity σ _p was determined in the same manner as the measurement of the ionic conductivity in the vertical direction. The absolute value of the conductivity σ _p was corrected with the measured value when the sample was in an isotropic liquid state.

(Orientation observation)
The liquid crystal phase was observed using a polarizing microscope (manufactured by Olympus).

(Synthesis Example 1)
A liquid crystal compound corresponding to n = 3, R ₁ = CN group, R ₂ = octyloxy group, and X = COO group in the general formula (Chemical Formula 1) was synthesized according to the scheme shown in FIG. The compound was identified by ¹ H and ¹³ C NMR measurements. Hereinafter, each compound is expressed as “Compound 1” or the like by the numbers given in FIG.

[Synthesis of Compound 3]
To a 10 mL solution of 2,4-dihydroxybenzoic acid (3.02 g, 19.6 mmol) in dimethylformamide (DMF) was added sodium hydrogen carbonate (5.00 g, 59.5 mmol), and the mixture was brought to an argon atmosphere. Stir vigorously for hours. Benzyl bromide (4.01 g, 23.4 mmol) was added to this solution, and the mixture was further stirred vigorously at 70 ° C. for 10 hours. After the reaction solution was cooled to room temperature, ethyl acetate and a saturated aqueous ammonium chloride solution were added to extract the organic layer, and the organic layer was washed with a saturated aqueous sodium chloride solution. Magnesium sulfate was added, the organic layer was dried and filtered, and then the solvent was distilled off under reduced pressure using a rotary evaporator. The residue was purified by silica gel chromatography (developing solvent: dichloromethane) to obtain Compound 3 as a white solid in 89% yield (4.26 g, 17.4 mmol).

[Synthesis of Compound 4]
To a solution of compound 3 (4.26 g, 17.4 mmol) and octyl bromide (3.69 g, 19.1 mmol) in 50 mL of DMF was added potassium carbonate (8.00 g, 57.9 mmol), and the mixture was brought to an argon atmosphere. Stir vigorously for 5 hours. Ethyl acetate and saturated aqueous ammonium chloride solution were added to the reaction solution to extract the organic layer, and the organic layer was washed with saturated aqueous sodium chloride solution. Magnesium sulfate was added, the organic layer was dried and filtered, and then the solvent was distilled off under reduced pressure using a rotary evaporator. The residue was purified by silica gel chromatography (developing solvent: hexane) to obtain Compound 4 as a white solid in 68% yield (4.19 g, 11.8 mmol).

[Synthesis of Compound 5]
To a solution of compound 4 (1.01 g, 2.83 mmol) and triethylene glycol monomethyl ether monotosylate (1.06 g, 3.33 mmol) in 50 mL of DMF was added potassium carbonate (1.28 g, 9.26 mmol), and the mixture was placed in an argon atmosphere. Then, the mixture was vigorously stirred at 70 ° C. for 3 hours. Ethyl acetate and saturated aqueous ammonium chloride solution were added to the reaction solution to extract the organic layer, and the organic layer was washed with saturated aqueous sodium chloride solution. Magnesium sulfate was added, the organic layer was dried and filtered, and then the solvent was distilled off under reduced pressure using a rotary evaporator. The residue was purified by silica gel chromatography (developing solvent: hexane / ethyl acetate = 5/1) to obtain Compound 5 as a colorless viscous liquid in a yield of 96% (1.37 g, 2.73 mmol).

¹ H NMR (CDCl ₃ , 400 MHz): δ = 0.89 (t, J = 6.8 Hz, 3H), 1.25-1.46 (m, 10H), 1.74-1.81 (m, 2H), 3.36 (s, 3H), 3.51 -3.70 (m, 8H), 3.84 (t, J = 5.1Hz, 2H), 3.96 (t, J = 6.6Hz, 2H), 4.16 (t, J = 5.1Hz, 2H), 5.30 (s, 2H) , 6.46-6.49 (m, 2H), 7.27-7.45 (m, 5H), 7.87 (d, J = 4.6Hz, 1H) 13 C NMR (CDCl 3, 100MHz):. δ = 13.95, 22.48, 25.80, 28.94 , 29.05, 29.15, 31.62, 58.83, 65.95, 68.07, 68.54, 69.23, 70.31, 70.47, 70.72, 71.74, 100.42, 105.63, 112.15, 127.76, 127.90, 128.27, 133.80, 136.40, 160.52, 163.68, 165.36.

[Synthesis of Compound 6]
Sodium hydroxide (0.63 g, 15.8 mmol) was added to a solution of compound 5 (1.37 g, 2.73 mmol) in 50 mL of ethanol and stirred at reflux for 3 hours. The reaction solution was cooled to room temperature and neutralized by adding 5% aqueous hydrochloric acid. The solvent was distilled off under reduced pressure using a rotary evaporator, ethyl acetate and water were added to the residue, and the organic layer was extracted. Magnesium sulfate was added to the organic layer, dried and filtered, and then the solvent was distilled off under reduced pressure using a rotary evaporator. The residue was purified by silica gel chromatography (developing solvent: hexane / ethyl acetate = 5/1) to obtain Compound 6 as a colorless viscous liquid in a yield of 71% (0.80 g, 1.94 mmol).

¹ H NMR (CDCl ₃ , 400 MHz): δ = 0.89, (t, J = 6.8Hz, 3H), 1.25-1.49 (m, 10H), 1.76-1.83 (m, 2H), 3.37 (s, 3H), 3.53-3.55 (m, 2H), 3.64-3.75 (m, 6H), 3.92 (d, J = 4.4Hz, 2H), 4.00 (d, J = 6.6Hz, 2H), 4.33 (d, J = 4.6Hz , 2H), 6.51 (d, J = 2.0Hz, 1H), 6.61-6.64 (m, 1H), 8.09 (d, J = 8.8Hz, 1H), 10.82 (S, 1H). ¹³ C NMR (CDCl ₃ , 100MHz): δ = 14.05, 22.59, 22.88, 28.97, 29,14, 29.23, 31.71, 58.94, 68.51, 68.56, 68.93, 70.51, 70.53, 70.71, 71.79, 100.26, 107.55, 110,83, 135.23, 158.74, 164.42, 165.48.

[Synthesis of Compound 1]
Compound 6 (2.64 g, 6.40 mmol), 4′-hydroxy-4-cyanobiphenyl (1.58 g, 8.09 mmol), 4-dimethylaminopyridine (DMAP) (8.4 g, 0.069 mmol), 1 A solution of ethyl-3- (3-dimethylaminopropyl) -carbodiimide hydrochloride (ECD) (1.42 g, 7.41 mmol) in dichloromethane (50 mL) was stirred at room temperature for 3 hours. Ethyl acetate and saturated aqueous sodium chloride solution were added to the reaction solution, and the organic layer was extracted. Magnesium sulfate was added to the organic layer, dried and filtered, and then the solvent was distilled off under reduced pressure using a rotary evaporator. The residue was purified by silica gel chromatography (developing solvent: hexane / ethyl acetate = 4/1) to obtain Compound 1 as a white solid in a yield of 55% (2.06 g, 3.50 mmol).

¹ H NMR (CDCl ₃ , 400 MHz): δ = 0.81 (t, J = 6.8 Hz, 3H), 1.17-1.42 (m, 10H), 1.69-1.76 (m, 2H), 3,25 (s, 3H) , 3.41-3.43 (m, 2H), 3.51-3.55 (m, 4H), 3.65-3.68 (m, 2H), 3.83 (t, J = 5.1Hz, 2H), 3.94 (t, J = 6.6Hz, 2H ), 4.13 (t, J = 5.1Hz, 2H), 6.45-6.49 (m, 2H), 7.23 (d, J = 8.8Hz, 2H), 7.53 (d, J = 6.8Hz, 2H), 7.59 (d , J = 8, 3Hz, 2H ), 7.64 (d, J = 8.3Hz, 2H), 7.96 (d, J = 8.3Hz, 1H) 13 C NMR (CDCl 3, 100MHz):. δ = 13.57, 22.11, 25.43, 28.54, 28.67, 28.76, 31.25, 58.45, 67.86, 68.26, 68.94, 69.94, 70.10, 70.45, 71.34, 99.99, 105.47, 110.32, 110.50, 118.37, 122.19, 127.11, 127.72, 132.08, 133.90, 135.88, 144.41, 151.16, 160.87, 163.19,164.06.

  The obtained compound was examined for thermal phase transition behavior by differential scanning calorimetry and observation with a polarizing microscope. The melting point was 67 ° C., and a nematic liquid crystal phase was observed at −37 ° C. to 8 ° C. during cooling.

(Synthesis Example 2)
Instead of triethylene glycol monomethyl ether monotosylate, the liquid crystalline compound corresponding to n = 2, R ₁ = CN group, R ₂ = octyloxy group, X = COO group in the general formula (Chemical Formula 1) is replaced by diethylene glycol The compound was synthesized according to the scheme shown in FIG. 4 in the same manner as in Synthesis Example 1 except that monomethyl ether monotosylate was used. The compound was identified by ¹ H and ¹³ C NMR measurements.

Only the ¹ H and ¹³ C NMR of compound 2 is described below.

1H NMR (CDCl3, 400MHz): δ = 0.89 (t, J = 6.8Hz, 3H), 1.26-1.48 (m, 10H), 1.78-1.83 (m, 2H), 3.35 (s, 3H), 3.51-3.53 (m, 2H), 3.73-3.75 (m, 2H), 3.92-3.94 (m, 2H), 4.02 (t, J = 6.4Hz, 2H), 4.24 (t, J = 5.2Hz, 2H), 6.54- 6.58 (m, 2H), 7.32 (d, J = 8.8KHz, 2H), 7.62 (d, J = 8.8H, 2H), 7.68 (d, J = 8.4Hz, 2H), 7.74 (d, J = 8.4 . Hz, 2H), 8.05 ( d, J = 8.8Hz, 1H) 13 C NMR (CDCl 3, 100MHz): δ = 14.09, 22.63, 25.95, 29.07, 29.19, 29.30, 31.77, 57.70, 59.00, 68.40, 68.81 , 69.50, 70.90, 71.92, 100.50, 106.07, 110.85, 110.99, 118.90, 122.71, 127.64, 128.25, 132.61, 134.43, 136.43, 144.95, 151.67, 161.40, 163.72, 164.60.

  The obtained compound was examined for thermal phase transition behavior by differential scanning calorimetry and observation with a polarizing microscope. The melting point was 84 ° C., and a nematic liquid crystal phase was observed at 43 ° C. or lower during cooling.

Example 1
The liquid crystal compound obtained in Synthesis Example 1 and LiN (CF ₃ SO ₂ ) ₂ (manufactured by Kishida Chemical Co., Ltd., LiTFSi) were mixed at a molar ratio of 95: 5.

Using the ionic conductor thus obtained, a vertical ionic conductivity measurement cell was prepared. At this time, the ion conductor was dissolved at 100 ° C. By observing this cell with a polarizing microscope at room temperature, it was confirmed that the ionic conductor was in an isotropic liquid state. The ionic conductivity in the vertical direction at room temperature (ie, between the electrodes) was 1.0 × 10 ⁻⁷ S / cm.

(Example 2)
The liquid crystal compound obtained in Synthesis Example 1, 4′-pentyloxy-biphenyl-4-carbonitrile (5OCB, manufactured by Wako Chemical Co., Ltd.) in which R ₃ corresponds to a pentyl group in the general formula (Formula 3), 3) 4'-heptyloxy-biphenyl-4-carbonitrile (7OCB, manufactured by Wako Chemical Co., Ltd.) in which R ₃ corresponds to a heptyl group, and 4'- in which R ₈ in the general formula (Chemical Formula 8) corresponds to a pentyl group (4-Pentylcyclohexyl) -biphenyl-4-carbonitrile (manufactured by Valiant Fine Chemicals, BCH5) and LiTFSi (manufactured by Kishida Chemical) in a molar ratio of 50: 21.4: 21.4: 4.75: 5 so as to be mixed.

Using the ionic conductor thus obtained, a vertical ionic conductivity measurement cell was prepared. At this time, the ion conductor was dissolved at 100 ° C. By observing the cell with a polarizing microscope at room temperature, a schlieren structure of a nematic liquid crystal phase was observed. The ionic conductivity in the vertical direction at room temperature (that is, between the electrodes) was 2.3 × 10 ⁻⁷ S / cm, which was higher than that in Example 1.

(Example 3)
A liquid crystal compound obtained by Synthesis Example 2, 5OCB (manufactured by Wako Chemical) in which R ₃ corresponds to a pentyl group in the general formula (Chemical Formula 3), and 7OCB in which R ₃ in the general formula (Chemical Formula 3) corresponds to a heptyl group LiTFSi (manufactured by Kishida Chemical Co., Ltd.) was mixed so that the molar ratio was 9.5: 42.75: 42.75: 5.

Using the ionic conductor thus obtained, a vertical ionic conductivity measurement cell was prepared. At this time, the ion conductor was dissolved at 100 ° C. When the cell was observed with a polarizing microscope at room temperature, dark field was observed by orthoscope observation, and isogyre was observed by conoscopic observation. The ionic conductivity in the vertical direction at room temperature (ie, between the electrodes) was 3.8 × 10 ⁻⁶ S / cm. In addition, the ionic conductivity in the horizontal direction of this ionic conductor was 3.0 × 10 ⁻⁶ S / cm, which was slightly lower than the ionic conductivity in the vertical direction.

Example 4
A liquid crystal compound obtained by Synthesis Example 2, 5OCB (manufactured by Wako Chemical) in which R ₃ corresponds to a pentyl group in the general formula (Chemical Formula 3), and 7OCB in which R ₃ in the general formula (Chemical Formula 3) corresponds to a heptyl group , Tetraethylene glycol dimethyl ether corresponding to an ethylene oxide oligomer having 4 oxyethylene units having a methoxy group at the terminal (manufactured by Tokyo Chemical Industry) and LiTFSi (manufactured by Kishida Chemical Co., Ltd.) in a molar ratio of 3.8: 43. 7: 43.7: 3.8: 5 The mixture was mixed.

Using the ionic conductor thus obtained, a vertical ionic conductivity measurement cell was prepared. At this time, the ion conductor was dissolved at 100 ° C. When the cell was observed with a polarizing microscope at room temperature, dark field was observed by orthoscope observation, and isogyre was observed by conoscopic observation. The ionic conductivity in the vertical direction at room temperature (that is, between the electrodes) was 1.0 × 10 ⁻⁵ S / cm, which was higher than those in Examples 1 to 3.

  The ionic conductor of the present invention is non-volatile and has a high conductivity between electrodes which is important in practical use. The ion conductor of the present invention has a great utility value as a material for various devices represented by lithium ion batteries and fuel cells.

It is sectional drawing of the cell for ion conductivity measurement used in the Example of this invention. It is a top view of the spacer used for the cell of FIG. It is a top view which shows the comb-shaped electrode in the cell for horizontal direction ionic conductivity measurement used in the Example of this invention. 1 is a structural formula of a liquid crystal compound synthesized in an example of the present invention and a synthesis scheme thereof.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sample filling part 2 Spacer 3 ITO film 4 Glass electrode with ITO film 11 Comb electrode 12 Comb part 13 Measurement area

Claims (6)

A liquid crystal compound represented by the following general formula (Formula 1).

However, n is an integer of 1 to 5, R ₁ is a CN group or F, R ₂ is an alkyl group or an alkyloxy group having 5 to 10 carbon atoms, X is none or a COO group, Y is an alkyl group having 1 to 5 carbon atoms.   An ionic conductor comprising the liquid crystalline compound (A) according to claim 1 and an electrolyte.   The ionic conductor according to claim 2, further comprising a liquid crystal compound (B) which is a liquid crystal compound different from the liquid crystal compound (A) and exhibits a nematic liquid crystal phase. The ionic conductor according to claim 3, wherein the liquid crystal compound (B) is represented by any one of the following general formulas (Chemical Formula 2) to (Chemical Formula 6).

However, R ₂ is a linear alkyl group having 2 carbon atoms 8, R ₃ ~R ₆ is a straight-chain alkyl group having 2 to 10 carbon atoms.   The ionic conductor according to claim 3 or 4, comprising two or more liquid crystalline compounds (B).   The ionic conductor according to claim 2, further comprising an ethylene oxide oligomer.

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