JP2016199428A - Composition having ionic conductivity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition having ionic conductivity that maintains the high ionic conductivity of ionic liquid and has excellent flow characteristics.SOLUTION: A composition according to the present invention comprises imogolite with an average length of 1 μm or more and 10 μm or less, and ionic liquid, and has ionic conductivity.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a composition having ion conductivity.

  Ion conductive materials are involved in a wide range of industrial technologies, including batteries. Examples of widely used ion conductive materials include liquid electrolytes as disclosed in Patent Document 1. However, since many liquid electrolytes use an organic solvent, there is a concern about ignition, explosion, etc. when applied to batteries. Moreover, since it is liquid, sealing with a metal etc. was needed, and workability was low and weight reduction was difficult. Instead of such liquid electrolytes, solid electrolytes are being developed. Examples thereof include polymer electrolytes as disclosed in Patent Document 2 and Non-Patent Document 1. Such a polymer electrolyte is not easily ignited or leaked and has high workability, but its ionic conductivity is not always sufficient as compared with a liquid electrolyte.

  In recent years, an ionic liquid (hereinafter sometimes abbreviated as IL) has been attracting attention as an ion conductive material having high ion conductivity (see Patent Document 3 and Non-Patent Document 2). An ionic liquid is a kind of salt composed only of ions, but is a substance that takes a liquid state even near room temperature due to the size of molecules and the interaction between weak ions. Furthermore, the ionic liquid has the characteristics of (1) non-volatility, (2) high ionic conductivity, and (3) a wide liquidus temperature range, and is expected as an ionic conductive material. Since the ionic liquid is also a liquid, the processability and the like are not sufficient, and solidification is desired from this viewpoint. As an example of attempts to solidify, for example, Patent Document 4 and Non-Patent Document 3 disclose that constituent ions themselves are polymerized.

International Publication No. 2002/021631 JP 2010-287563 A US Patent Application Publication No. 2004/0097755 US Patent Application Publication No. 2014/0088207 JP 2013-213086 A

Y. Tominaga et al., Chem. Commun., 2014, 50, 4448 H. Ohno et al., Chem. Eng., 2011, 75, 376 P. Snedden et al., Macromolecules, 2003, 36, 4549

  However, if the ions constituting the ionic liquid are polymerized by the technique disclosed in Patent Document 4 and the like, the fluidity as the liquid can be suppressed, but the molecular motion of the constituent ions is inhibited, and the ionic conductivity is reduced. There was a problem of a decrease.

  By the way, the inventors are a polymer obtained by dispersing imogolite (hereinafter sometimes referred to as IG) in a solvent containing water and a water-soluble monomer, and polymerizing the water-soluble monomer, It has been found that the mechanical strength of a polymer can be improved by allowing imogolite to take a network structure (JP 2013-213086 A, etc.).

  Imogolite is a nanotube-like inorganic polymer made of aluminum and silicon. The outer shape of imogolite (IG) has a high aspect ratio with a length of several tens nm to several μm and an outer diameter of 2 nm to 3 nm. Moreover, since many hydroxyl groups exist on the surface of IG, it can be easily dispersed in a solvent such as water.

  Such imogolite can take a reversible network structure when dispersed in a medium. Therefore, when taking a network structure in the liquid, the viscosity can be increased or pseudoplasticity (thixotropic property) can be imparted. For example, while the fluidity at the time of fluidization is secured, It can be expected to reduce the fluidity.

  One of the objects according to some embodiments of the present invention is to provide an ion conductive composition that maintains high ionic conductivity of the ionic liquid and has excellent flow characteristics.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1] One aspect of the composition according to the present invention is:
Imogolite having an average length of 1 μm to 10 μm;
An ionic liquid,
And has ion conductivity.

  According to the composition of this application example, since the average length of imogolite is 1 μm or more and 10 μm or less, a plurality of imogolites are easily contacted and / or easily entangled in the ionic liquid. As a result, a reversible network structure of imogolite is formed in the composition. As a result, the composition of this application example can maintain the high ionic conductivity of the ionic liquid, and has low fluidity during standing, and The fluidity at the time of fluidity is high, and excellent fluidity can be exhibited. Therefore, workability is good when applied to batteries, conductive paints, and the like.

[Application Example 2] In Application Example 1,
The composition may have a shear strain region in which the loss elastic modulus G ″ is smaller than the storage elastic modulus G ′ in the dynamic viscoelasticity measurement.

  The composition of this application example has a shear strain region in which the loss elastic modulus G ″ is smaller than the storage elastic modulus G ′, and as a result, exhibits good fluidity during molding and good viscosity after molding. Therefore, the processability is good when applied to batteries, conductive paints, and the like.

[Application Example 3] One aspect of the composition according to the present invention is:
Imogolite having an average length of 50 nm to 10 μm,
An ionic liquid,
A polyfunctional compound;
And has ion conductivity.

  According to the composition of this application example, since the average length of imogolite is 50 nm or more and 10 μm or less and contains a polyfunctional compound, a plurality of imogolites can be reversibly crosslinked in an ionic liquid. . As a result, a reversible network structure is formed in the composition by the imogolite and the polyfunctional compound. As a result, the composition of this application example can maintain high ionic conductivity of the ionic liquid, and is also pseudoplastic (thixotropic). Property) and excellent flow characteristics. Therefore, workability is good when applied to batteries, conductive paints, and the like.

[Application Example 4] In Application Example 3,
In the dynamic viscoelasticity measurement, the composition may have a shear strain region in which the value of the loss modulus G ″ and the value of the storage modulus G ′ are reversed.

  The composition of this application example can exhibit good thixotropy as a result of having a shear strain region in which the value of the loss elastic modulus G ″ and the value of the storage elastic modulus G ′ are reversed. Workability is good when applied to conductive paints.

[Application Example 5] In Application Example 3 or Application Example 4,
The polyfunctional compound may be a bifunctional organic acid.

  According to the composition of this application example, a plurality of imogolites can be more efficiently and reversibly cross-linked in the ionic liquid.

[Application Example 6] In any one of Application Examples 3 to 5,
The polyfunctional compound is
A compound having 2 to 6 carbon atoms,
At least one group selected from a carboxyl group, a phosphoric acid group, a phosphoric acid group, a phosphorous acid group, a phosphonic acid group, a sulfonic acid group, and a sulfuric acid group;
At least one group selected from an amino group and a carboxamide group;
May be included.

  According to the composition of this application example, a plurality of imogolites can be more efficiently and reversibly cross-linked in the ionic liquid.

[Application Example 7] In any one of Application Examples 3 to 6,
The polyfunctional compound may be contained in an amount of 0.5% by mass to 4.2% by mass with respect to the total mass.

  According to the composition of this application example, a plurality of imogolites can be more efficiently and reversibly cross-linked in the ionic liquid.

[Application Example 8] In any one of Application Examples 1 to 7,
The imogolite may be contained in an amount of 2% by mass to 10% by mass with respect to the total mass.

  According to the composition of this application example, the plurality of imogolites are more likely to come into contact with each other in the ionic liquid, or the plurality of imogolites are easily reversibly crosslinked. Thereby, the further outstanding flow characteristic can be shown.

[Application Example 9] In any one of Application Examples 1 to 8,
The ionic liquid may be at least one selected from imidazolium salts, pyridinium salts, pyrrolidinium salts, phosphonium salts, ammonium salts, guanidinium salts, isouronium salts, and isothiouronium salts.

  According to the composition of this application example, further excellent ion conductivity can be exhibited.

The schematic diagram which shows the structure of imogolite (IG). The figure which shows the TEM observation result of IG which concerns on an experiment example. The figure which shows the FT-IR measurement result of IG which concerns on an experiment example. The figure which shows the TG-DTA measurement result of IG which concerns on an experiment example. The figure which shows the XRD measurement result of IG which concerns on an experiment example. The figure which shows the external appearance observation result of IG-IL (composition) which concerns on an experiment example. The figure which shows the TEM observation result of IG-IL (composition) which concerns on an experiment example. The figure which shows the external appearance observation result and TEM observation result of IG-IL-DA which concern on an experiment example. The Arrhenius plot of the measurement result of the ionic conductivity which concerns on an experiment example. The Arrhenius plot of the measurement result of the ionic conductivity which concerns on an experiment example. The Arrhenius plot of the measurement result of the ionic conductivity which concerns on an experiment example.

  Several embodiments of the present invention will be described below. The embodiments described below illustrate examples of the present invention. The present invention is not limited to the following embodiments, and includes various modified embodiments that are implemented within a range that does not change the gist of the present invention. Note that not all of the configurations described below are essential configurations of the present invention.

  The composition according to the present invention has ionic conductivity. In the first embodiment of the composition according to the present invention, imogolite having an average length of 1 μm or more and 10 μm or less and an ionic liquid are included. Moreover, in 2nd Embodiment of the composition based on this invention, the average length contains 50 nm or more and 10 micrometer or less imogolite, an ionic liquid, and a polyfunctional compound. Hereinafter, as an example of an embodiment of the present invention, a first embodiment and a second embodiment will be described in order.

1. 1st Embodiment The composition of this embodiment contains the imogolite whose average length is 1 micrometer or more and 10 micrometers or less, and an ionic liquid.

1.1. Imogolite Imogolite (hereinafter sometimes referred to as “IG”) is a cylindrical inorganic polymer composed of the basic unit (OH) ₃ Al ₂ O ₃ SiO, and contains aluminum chloride and sodium orthosilicate. It can be obtained by thermal polymerization under suitable pH conditions (FIG. 1; VCFarmeretal., J. Chem. Soc. Chem. Comm., 1977, 13, 462). The chemical composition formula of IG can also be expressed as Al ₂ SiO ₃ (OH) ₄ , but the composition measured by analysis or the like may deviate somewhat from the composition formula.

  It is reported that IG is a rigid cylindrical molecule having a cylinder length of 100 nm to several tens of μm, a cylinder outer diameter of 2 nm to 2.5 nm, and a cylinder inner diameter of about 1 nm (N. Donkaietal. Macromol. Chem. 1985, 186, 2623). That is, IG has a very high aspect ratio. Further, an Al—OH group is arranged on the outer surface of the cylinder of the IG, and an Si—OH group is arranged on the inner surface of the cylinder. When such IG is dispersed in an aqueous solvent, its dispersibility changes depending on the pH of the aqueous solvent. For example, under acidic and neutral conditions, it is dispersed in the form of a single filament or a thin bundle. In addition, it has been reported that, under basic conditions, a thick bundle may be dispersed or a network may be formed (J. Karube, ClaysClayMiner. 1998, 46 (5), 583).

The IG in the present embodiment has an average length of 1 μm or more and 10 μm or less. The average length of IG can be adjusted by, for example, a ball mill, a bead mill, a jet mill and / or ultrasonic crushing. Among these, it is more preferable to disperse IG in an appropriate solvent or an ionic liquid to be described later and adjust by irradiating ultrasonic waves because the distribution of IG length can be made relatively small. Here, the average length of the IG is the number average length, and the length distribution is not particularly limited, and may include an IG having a length of 1 μm or less, or including an IG having a length of 10 μm or more. But you can.

  The average length of IG in the composition of the present embodiment is 1 μm or more and 10 μm or less, preferably 1.3 μm or more and 10 μm or less, more preferably 1.5 μm or more and 10 μm or less, and further preferably 1.6 μm or more and 10 μm or less. It is.

  In addition, IG may be produced from a naturally occurring mineral, but it is more advantageous to obtain it by chemical synthesis as described above for reasons such as easier adjustment of the average length, fewer impurities, and lower costs. .

  Since the IG used in the present embodiment has an average length of 1 μm or more, when it is dispersed in an ionic liquid described later, it is likely to contact or entangle with each other. A network structure is formed in the ionic liquid by contacting and / or entwining a plurality of IGs. When such a network structure is formed, the viscosity of the composition increases, and a paste or solid property is obtained.

  Thus, although IG can form network structure in an ionic liquid, the addition amount of IG with respect to the whole composition is 0.1 mass% or more, for example. The ease of forming a network structure depends on the average length of IG, and the longer the average length, the smaller the addition amount. For example, when the average length of IG is about 1 μm, the amount of IG added to the entire composition is 0.01% by mass to 10% by mass, preferably 0.1% by mass to 8% by mass, More preferably, it is 1 mass% or more and 7 mass% or less. For example, when the average length of IG is about 10 μm, the amount of IG added to the whole composition is 0.001% by mass to 8% by mass, preferably 0.05% by mass to 7% by mass. More preferably, it is 0.1 mass% or more and 5 mass% or less.

  The compounding quantity of IG in a composition can be calculated | required by the method of a general chemical analysis and an instrumental analysis. The identification of IG is, for example, transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction (XRD) ) And the like.

1.2. Ionic liquid The composition of this embodiment contains an ionic liquid. An ionic liquid (hereinafter sometimes referred to as “IL”) is a kind of salt composed of only ions, but it is in a liquid or solid state depending on temperature due to molecular size and weak ionic interaction. It is a substance that takes Furthermore, the ionic liquid has the characteristics of (1) non-volatility, (2) high ionic conductivity, and (3) a wide liquidus temperature range.

  In the composition of this embodiment containing an ionic liquid whose temperature is adjusted to be liquid, the above-mentioned average length increases due to the presence of imogolite having a size of 1 μm or more and 10 μm or less, or becomes a paste solid property.

The ionic liquid blended in the composition of the present embodiment is not particularly limited, and a known ionic liquid can be used. Examples of the ionic liquid include at least one selected from imidazolium salts, pyridinium salts, pyrrolidinium salts, phosphonium salts, ammonium salts, guanidinium salts, isouronium salts, and isothiouronium salts. These salts may be used as a mixture of plural kinds. The anion species of these salts are not particularly limited, and examples thereof include halide ions (I ⁻ , Cl ⁻ , Br ⁻ etc.), SCN ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , SbF ₆ ⁻ , (CF ^{_{3 SO 2) 2 N -,}} (CF 3 CF 2 SO 2) 2 N -, Ph 4 B -, (C 2 H 4 O 2) 2 B -, (CF 3 SO 2) 3 C -, CF 3 COO _{^{-, CF 3 SO 3 -,}} C 6 F 5 SO 3 -, MeO (EtO) 2 SO 3 - , and the like.

  Specific examples of the ionic liquid of the imidazolium salt include 1,3-dimethylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium bis [oxalate (2-)] borate, 1-ethyl-3-methylimidazole. 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium Trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium methylsulfate, 1-ethyl-3-methylimidazolium p-toluenesulfonate, 1-ethyl-3-methyl Imidazolium thiocyanate, 1-ethyl-3-methylimidazolium 2- (2-methoxyethoxy) ethyl sulfate, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazole 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium methyl sulfate, 1-butyl-3- Methyl imidazolium chloride, 1-butyl-3-methyl imidazolium bromide, 1-butyl-3-methyl imidazolium trifluoroacetate, 1-butyl-3-methyl imidazolium octyl sulfate, 1-hex -3-Methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluoro Phosphate, 1-hexyl-3-methylimidazolium tris (pentafluoroethyl) trifluorophosphate, 3-methyl-1-octylimidazolium hexafluorophosphate, 3-methyl-1-octylimidazolium chloride, 3-methyl -1-octylimidazolium tetrafluoroborate, 3-methyl-1-octylimidazolium bis (trifluoromethylsulfonyl) imide, 3-methyl-1-octylimidazolium octyl sulfate, 3 -Methyl-1-tetradecylimidazolium tetrafluoroborate, 1-hexadecyl-3-methylimidazolium chloride, 3-methyl-1-octadecylimidazolium hexafluorophosphate, 3-methyl-1-octadecylimidazolium bis (tri Fluoromethylsulfonyl) imide, 3-methyl-1-octadecylimidazolium tri (pentafluoroethyl) trifluorophosphate, 1-ethyl-2,3-dimethylimidazolium bromide, 1-ethyl-2,3-dimethylimidazolium tetra Fluoroborate, 1-ethyl-2,3-dimethylimidazolium hexafluorophosphate, 1-ethyl-2,3-dimethylimidazolium chloride, 1-ethyl-2,3-dimethylimidazolium p-tolue Sulfonate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium chloride, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butyl- Examples include 2,3-dimethylimidazolium octyl sulfate, 1-hexyl-2,3-dimethylimidazolium chloride, 1-hexadecyl-2,3-dimethylimidazolium chloride and the like.

Specific examples of the ionic liquid of the pyridinium salt include N-ethylpyridinium chloride, N-ethylpyridinium bromide, N-butylpyridinium chloride, N-butylpyridinium tetrafluoroborate, N-butylpyridinium hexafluorophosphate, N-butylpyridinium Trifluoromethanesulfonate, N-hexylpyridinium tetrafluoroborate, N-hexylpyridinium hexafluorophosphate, N-hexylpyridinium bis (trifluoromethylsulfonyl) imide, N-hexylpyridinium trifluoromethanesulfonate, N-octylpyridinium chloride, 4- Methyl-N-butylpyridinium chloride, 4-methyl-N-butylpyridinium tetrafluoroborate, 4-methyl- - butyl pyridinium hexafluorophosphate,
Examples include 3-methyl-N-butylpyridinium chloride, 4-methyl-N-butylpyridinium bromide, 3,4-dimethyl-N-butylpyridinium chloride, 3,5-dimethyl-N-butylpyridinium chloride.

  Specific examples of pyrrolidinium salt ionic liquids include: 1-butyl-1-methylpyrrolidinium chloride, 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, 1-butyl-1-methylpyrrolidinium bis ( Trifluoromethylsulfonyl) imide, 1-butyl-1-methylpyrrolidinium tetrafluoroborate, 1-butyl-1-methylpyrrolidinium hexafluorophosphate, 1-butyl-1-methylpyrrolidinium tris (pentafluoro) Ethyl) trifluorophosphate, 1-butyl-1-methylpyrrolidinium trifluoroacetate, 1-hexyl-1-methylpyrrolidinium chloride, 1-methyl-1-octylpyrrolidinium chloride and the like.

  Specific examples of ionic liquids of phosphonium salts include trihexyl (tetradecyl) phosphonium chloride, trihexyl (tetradecyl) phosphonium tris (pentafluoroethyl) trifluorophosphate, trihexyl (tetradecyl) phosphonium tetrafluoroborate, trihexyl (tetradecyl) phosphonium bis (tri Fluoromethylsulfonyl) imide, trihexyl (tetradecyl) phosphonium hexafluorophosphate, trihexyl (tetradecyl) phosphonium bis [oxalate (2-)] borate and the like.

  Specific examples of the ionic liquid of the ammonium salt include methyl trioctyl ammonium trifluoroacetate, methyl trioctyl ammonium trifluoromethanesulfonate, methyl trioctyl ammonium bis (trifluoromethylsulfonyl) imide and the like.

  Specific examples of ionic liquids of guanidinium salts include: N) -ethyl-N, N, N ′, N′-tetramethylguanidinium tris (pentafluoroethyl) trifluorophosphate, guanidinium tris (pentafluoroethyl) ) Trifluorophosphate, guanidinium trifluoromethanesulfonate, N ″ -ethyl-N, N, N ′, N′-tetramethylguanidinium trifluoromethanesulfonate.

  Specific examples of ionic liquids of isouronium salts include O-ethyl-N, N, N ′, N′-tetramethylisouronium trifluoromethanesulfonate, O-ethyl-N, N, N ′, N′-tetramethyl. An isouronium tri (pentafluoroethyl) trifluorophosphate may be mentioned.

  Specific examples of the ionic liquid of isothiouronium salt include S-ethyl-N, N, N ′, N′-tetramethylisothiouronium trifluoromethanesulfonate, S-ethyl-N, N, N ′, N′— Examples include tetramethylisothiouronium tris (pentafluoroethyl) trifluorophosphate.

As already described, since the Al—OH group is present on the outer surface of the IG cylinder, the ionic liquid is hydrophilic from the viewpoint that IG is more easily dispersed in the composition. It is preferable to use a high one. Examples of such ionic liquids include 1-ethyl-3-methylimidazolium 2- (2-methoxyethoxy) ethyl sulfate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methyl. Examples thereof include imidazolium tetrafluoroborate.
The content of the ionic liquid in the composition of the present embodiment is not particularly limited.

1.3. Other Components The composition of the present embodiment can contain various substances in addition to the above-described IG and IL as long as the fluidity and ion conductivity are not impaired. Examples of such substances include inorganic oxide particles, supporting electrolyte salts, surfactants, water, and the like, which can be appropriately blended depending on the purpose. Moreover, these substances may be contained as impurities.

As inorganic oxide particles, Li, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Y, Nb, Zr Of one or more metals selected from the group consisting of Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, La, Ta, Hf, W, Ir, Tl, Pb, Bi and rare earth metals Examples of the particles include oxides, and specific examples include titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, calcium oxide, strontium oxide, and barium oxide. , Indium oxide, tin oxide, lead oxide, scandium oxide, yttrium oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, summer Au, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, lutetium oxide, and complex oxides composed of these oxides, lithium niobate and potassium niobate , Lithium tantalate, aluminum / magnesium oxide (MgAl ₂ O ₄ ), and the like, and a plurality of these may be used.

Further, as the supporting electrolyte salt, a salt of a metal ion belonging to Group Ia or Group IIa of the periodic table may be used. As the metal ions belonging to Group Ia or Group IIa of the periodic table, ions of lithium, sodium and potassium are preferable. As the anion of the metal ion salt, the anions exemplified in the section of the ionic liquid described above can be used. Typical supporting electrolyte salts include LiCF ₃ SO ₃ , LiPF ₆ , LiClO ₄ , LiI, LiBF ₄ , LiCF ₃ CO ₂ , LiSCN, LiN (SO ₂ CF ₃ ) ₂ , NaI, NaCF ₃ SO ₃ , NaClO _4. , NaBF ₄ , NaAsF ₆ , KCF ₃ SO ₃ , KSCN, KPF ₆ , KClO ₄ , KAsF _{6 and the} like.

1.4. Flow characteristics and ionic conductivity of the composition The composition of the present embodiment exhibits non-Newtonian properties. That is, as a result of the contact and / or entanglement of IG in IL, the viscosity increases particularly in a region where the shear rate is low as compared with the case of IL alone. In other words, the composition of the present embodiment has a shear strain region in which the loss elastic modulus G ″ is smaller than the storage elastic modulus G ′ in the dynamic viscoelasticity measurement. The method can be used.

  For this reason, the composition of this embodiment behaves as a pasty, gel-like or solid high-viscosity viscoelastic body when left standing, but is deformed, fluidized, or applied to an object. In some cases, it can behave as a low-viscosity viscoelastic body. Thereby, for example, when introduced into a suitable container, it is in a liquid state, and when left in the container, a thickened state can be formed.

  Moreover, in the composition of this embodiment, the ion of an ionic liquid is hardly restrained by IG and can exist in a state with a high freedom degree of movement. Such a state can be maintained even when the composition is allowed to stand and becomes a pasty or solid high-viscosity viscoelastic body.

The ionic conductivity of the composition of the present embodiment can be calculated, for example, by measuring complex impedance. As a specific measurement, for example, a sample sandwiched between electrodes made of SUS can be performed in a glove box with a circulation purifier in a dry argon atmosphere using Potentiostat / Galvanostat SP-150 (manufactured by BioLogic). . The measurement frequency range is not limited, but is, for example, 100 Hz to 1 MHz.

The value of ionic conductivity of the composition of the present embodiment is 1 × 10 ⁻⁴ (S / cm) or more, preferably 2 × 10 ⁻⁴ (S) in a temperature range of about 30 ° C. or more and 100 ° C. or less. / Cm) or more, more preferably 1 × 10 ⁻³ (S / cm) or more. If the ionic conductivity of the composition of this embodiment is in this range, it can be said that it has good ionic conductivity.

1.5. Effects According to the composition of the present embodiment (first embodiment), the average length of imogolite to be blended is 1 μm or more and 10 μm or less. Therefore, a plurality of imogolites are likely to contact and / or easily entangle with each other in the ionic liquid. As a result, a reversible network structure of imogolite is formed in the composition. As a result, the high ionic conductivity of the ionic liquid can be maintained, the flowability at the time of standing is low, and the flowability at the time of flow is high. It can exhibit excellent flow characteristics. Therefore, the composition having good ion conductivity and processability is suitable for application to batteries, conductive paints, and the like.

2. Second Embodiment The composition of the present embodiment includes imogolite having an average length of 50 nm to 10 μm, an ionic liquid, and a polyfunctional compound.

2.1. Imogolite (IG) blended in the composition of the second embodiment has an average length of 50 nm to 10 μm. The adjustment, distribution, synthesis, and the like of the average length of IG are the same as described in the first embodiment, and a description thereof is omitted.

  The average length of IG in the composition of the present embodiment is from 50 nm to 10 μm, preferably from 80 nm to 10 μm, more preferably from 100 nm to 10 μm, and still more preferably from 130 nm to 10 μm.

  When the IG used in the present embodiment is dispersed in an ionic liquid together with a polyfunctional compound described later, the IG is easily linked to each other via a non-covalent bond by the polyfunctional compound. By reversibly bonding a plurality of IGs, a network structure at a molecular level is formed by IGs and polyfunctional compounds in the composition. When such a network structure is formed, the composition exhibits pseudoplasticity (thixotropic properties).

  The IG used in the composition of the present embodiment may have a smaller average length than the IG used in the composition of the first embodiment. This is because a plurality of IGs are non-covalently bonded by a polyfunctional compound by the polyfunctional compound. Examples of the non-covalent bond include ionic bonds, and include a bond by an electric attractive force between a hydroxyl group on the IG surface and a carboxyl group of a polyfunctional compound. Here, the hydroxyl group and the carboxyl group are reversible bonds because they do not form a covalent bond such as an ester bond. For example, when a flow due to shearing occurs, the position of the molecule is not fixed. .

In this embodiment, although IG can form a network structure in a composition with a polyfunctional compound, the addition amount of IG with respect to the whole composition is 0.01 mass% or more, for example. Also in this embodiment, the ease of forming a network structure depends on the average length of IG, and the smaller the amount added, the longer the average length. For example, when the average length of IG is about 1 μm, the amount of IG added to the entire composition is 0.01% by mass or more and 8% by mass or less, preferably 0.1% by mass or more and 7% by mass or less, More preferably, it is 1 mass% or more and 6 mass% or less. For example, when the average length of IG is about 100 nm, the amount of IG added to the entire composition is 1% by mass or more and 7% by mass or less, preferably 1.5% by mass or more and 6% by mass or less. Preferably they are 2 mass% or more and 5 mass% or less.

  The compounding quantity of IG and a polyfunctional compound in the composition of this embodiment can be calculated | required by the method of a general chemical analysis and an instrumental analysis.

2.2. Ionic liquid The ionic liquid used in the composition of the present embodiment is the same as that of the first embodiment, and thus detailed description thereof is omitted. The content of the ionic liquid in the composition of the present embodiment is not particularly limited.

2.3. Polyfunctional compound The composition of this embodiment (2nd Embodiment) contains a polyfunctional compound. The number of functional groups of the polyfunctional compound is not particularly limited as long as it is plural, but it is preferably two and bifunctional in that the crosslinking density when reversibly crosslinking between IGs is not too high. It is preferable that it is an ionic compound.

  Examples of the polyfunctional compound include a compound having two acidic functional groups, a compound having one acidic functional group, and one non-acidic functional group. Here, the acidic functional group refers to a functional group capable of releasing hydrogen ions in the compound. Examples of the acidic functional group include a carboxyl group, a phosphoric acid group, a phosphoric acid group, a phosphorous acid group, a phosphonic acid group, a sulfonic acid group, and a sulfuric acid group. Among them, a carboxyl group and a phosphonic acid group are preferable.

  Preferably, the compound having two acidic functional groups has a carboxyl group as the first functional group (acidic functional group) and has a carboxyl group or a phosphonic acid group as the second functional group (acidic functional group). It is. Examples of the compound having a carboxyl group as the first functional group and a carboxyl group as the second functional group include maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, citraconic acid, and mesaconic acid. Can be mentioned. Moreover, as a compound which has a carboxyl group as a 1st functional group and has a phosphonic acid group as a 2nd functional group, 4-phosphonobutanoic acid (PBA) etc. are mentioned, for example.

The acidic functional group in the compound having one acidic functional group and one non-acidic functional group can be the above-described acidic functional group. Examples of non-acidic functional groups include amino groups and acid amide groups. The acid amide group refers to a group formed by a reaction between an acid (oxo acid) and ammonia or an amine, and —OH (number is not particularly limited, but preferably 1) in the acidic functional groups exemplified above. Refers to a group substituted with an amino group. Examples of the acid amide group include a carboxamide group (—CONH ₂ ), a sulfonamide group (—SO ₂ NH ₂ ), and a phosphoric acid amide (—PO (OH) NH ₂ ). Among these, as the acid amide group, a carboxamide group is preferable, and those derived from a carboxyl group are preferable. Examples of the compound having one acidic functional group and one acid amide group include maleic acid monoamide, fumaric acid monoamide, succinic acid monoamide, glutaric acid monoamide, adipic acid monoamide, citraconic acid monoamide, and mesaconic acid monoamide. It is done. The compound having one acidic functional group and one acid amide group preferably has a carboxyl group as the acidic functional group and a carboxamide group as the acid amide group.

In addition, the compound having two acidic functional groups or the compound having one acidic functional group and one acid amide group (hereinafter referred to as a bifunctional compound) has 2 to 6 carbon atoms. Is more preferable. The carbon number includes carbon atoms contained in the functional group. The main chain is preferably composed of a carbon-carbon single bond or a double bond, and when a double bond is included, the number is preferably 1 or 2.

  The compounding quantity of the polyfunctional compound in the composition of this embodiment is not specifically limited, For example, it is 0.1 mass% or more with respect to the whole composition. You may adjust the compounding quantity of a polyfunctional compound with the average length of IG, and the compounding quantity of IG, for example. For example, when the amount of IG added to the entire composition is small, the blending amount may be increased to compensate for this. Moreover, when the average length of IG is long, you may make a compounding quantity small.

  Specifically, for example, when the average length of IG is about 50 nm to 1.5 μm and the content of IG is about 0.01% by mass to 5% by mass, blending of a multifunctional compound The amount is from 0.1% by weight to 15% by weight, preferably from 0.3% by weight to 10% by weight, more preferably from 0.5% by weight to 5% by weight, and even more preferably from 0.5% by weight. It is 4.2 mass% or less.

2.4. Other components In the composition of the present embodiment (second embodiment), in addition to the above-described IG, IL, and multifunctional compound, various substances can be included as long as fluidity and ion conductivity are not inhibited. . Examples of such substances include inorganic oxide particles, supporting electrolyte salts, surfactants, water, and the like, which can be appropriately blended depending on the purpose. Moreover, these substances may be contained as impurities. Since these details are the same as those in the first embodiment, description thereof will be omitted.

2.5. Flow characteristics and ionic conductivity of the composition The composition of the present embodiment exhibits thixotropic properties (pseudoplasticity). That is, as a result of IG reversible non-covalent bonding in the IL together with the polyfunctional compound, the viscosity is lowered particularly in a region where the shear rate is large as compared with the case of IL alone. In other words, the composition of the present embodiment has a shear strain region in which the value of the loss elastic modulus G ″ and the value of the storage elastic modulus G ′ are reversed in the dynamic viscoelasticity measurement. Elasticity measurement can be performed by a known method.

  For this reason, the composition of this embodiment behaves as a gel-like or solid high-viscosity viscoelastic body when allowed to stand, and is deformed, fluidized, or sheared when applied to an object. In a large area, it can behave as a low-viscosity viscoelastic body. Thereby, for example, when introduced into a suitable container, it is in a liquid state, and when left in the container, a thickened state can be formed.

  Moreover, also in the composition of this embodiment, the ion of an ionic liquid is hardly restrained by IG and can exist in a state with a high freedom degree of movement. Such a state can be maintained even when the composition is allowed to stand and is a solid high-viscosity viscoelastic body.

The ionic conductivity of the composition of the present embodiment can be measured in the same manner as described in the first embodiment. The value of the ionic conductivity of the composition of the present embodiment is 2 × 10 ⁻⁴ (S / cm) or more, preferably 5 × 10 ⁻⁴ (S) in a temperature range of about 30 ° C. to 100 ° C. / Cm) or more, more preferably 1 × 10 ⁻³ (S / cm) or more. If the ionic conductivity of the composition of this embodiment is in this range, it can be said that it has good ionic conductivity.

2.6. Effects According to the composition of the present embodiment (second embodiment), the average length of imogolite is 50 nm or more and 10 μm or less, and contains a polyfunctional compound. It can crosslink reversibly. As a result, a reversible network structure is formed in the composition by the imogolite and the polyfunctional compound. As a result, high ionic conductivity of the ionic liquid can be maintained, and pseudoplasticity (thixotropic property) can be exhibited. Excellent flow characteristics. As a composition having good ion conductivity and workability, it is suitable for application to batteries, conductive paints and the like.

3. Experimental Examples The experimental examples are shown below to further explain the present invention, but the present invention is not limited to the following examples.

3.1. Synthesis of imogolite (IG) and preparation of aqueous dispersion of IG Reagents used in this section were purchased from Wako Pure Chemical. After mixing an aluminum chloride aqueous solution (0.10 M, 369 mL) and a sodium orthosilicate aqueous solution (0.11 M, 362 mL), an aqueous NaOH (1 M) solution was slowly added dropwise to adjust to pH = 6. The mixture was stirred at room temperature for 1 hour to obtain a white IG precursor aqueous solution.

The IG precursor aqueous solution was centrifuged (5000 × g, 15 minutes × 3 + 30 minutes × 1), and the resulting pellet was washed with 400 mL of ultrapure water to remove chloride ions from the system. The residue obtained by centrifugation was dispersed in 2800 mL of ultrapure water, and an aqueous HCl (1M) solution was slowly added dropwise to adjust the pH to 4.5. The mixture was heated to reflux at 100 ° C. for 96 hours to obtain an IG dispersion (LIGaq .; average length 1.6 μm, hereinafter, IG at this point may be referred to as “LIG” (Long IG)). IG was aggregated by adding NaCl to the dispersion, and IG was isolated as a pellet by centrifugation (5000 × g). The pellet was washed and suction filtered with 1600 mL of ultrapure water to obtain a gel-like IG from which NaCl was removed.

  Then, after reprecipitation using tetrahydrofuran (THF) as a poor solvent, IG powder was obtained by vacuum drying at room temperature for 8 hours. A predetermined amount of IG powder was mixed with ultrapure water and subjected to ultrasonic treatment for 4 hours to obtain an IG dispersion (IG-131aq .; average length of 131 nm; hereinafter, this IG may be referred to as “IG-131”). Obtained. IG-131 was identified by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry-differential thermal analysis (TG-DTA), and X-ray diffraction (XRD).

  TEM was observed with an acceleration voltage of 200 kV by JEM-2100 (manufactured by JEOL Ltd.). An aqueous dispersion was dropped onto a copper mesh (150 mesh) with a formval film, and the excess dispersion was blotted with a filter paper and dried. The observation result of IG-131 is shown in FIG.

  FT-IR was measured by FT / IR-4100 (manufactured by JASCO Corporation). After mixing the IG powder with the potassium bromide fine powder, the pellet formed by applying pressure was used as a measurement sample. The measurement result of IG-131 is shown in FIG.

  TG-DTA was measured by Rigaku Thermo Plus TG8129 (manufactured by Rigaku Corporation). The change in weight was measured under dry nitrogen at a heating rate of 10 ° C./min in the range of room temperature to 1000 ° C. The measurement result of IG-131 is shown in FIG.

  XRD was measured by SmartLab (manufactured by Rigaku Corporation). It measured in the range of 3 degrees-70 degrees with respect to the IG powder put on the glass plate at room temperature. The measurement result of IG-131 is shown in FIG.

  From the results of the above measurements, it was confirmed that cylindrical IG was synthesized.

3.2. Preparation and evaluation of imogolite (IG) -ionic liquid (IL) complex IG-131aq. And LIGaq. Were each mixed with ionic liquid (IL). I
L may be abbreviated as 1-Ethyl-3-methylimidazolium 2- (2-Methoxyethoxy) ethyl Sulfate ([EmIm] [MeSO ₃ ]) and 1-Butyl-3-methylimidazolium Tetrafluoroborate ([BmIm] [BF ₄ ] may be abbreviated.) (Both manufactured by Tokyo Chemical Industry Co., Ltd.). In order to remove water from the mixture, the mixture was evaporated at 60 ° C. for 3 hours, and further dried under vacuum heating at 60 ° C. for 12 hours. As a result, a composition (IG-IL) in which IG and IL were uniformly mixed was obtained.

  IG-1100; average length 1.1 μm, IG-800; average length 0.8 μm were prepared in the same manner as IG-131 except that the time of ultrasonic irradiation was changed to 1 hour and 2 hours. The types and blending amounts of IG and IL in each experimental example are shown in Table 1.

External appearance photograph (FIG. 6 (a)) of IG-IL (Experimental Example 1) using IG-131 and [EmIm] [MeSO ₃ ] as raw materials, and LIG and [EmIm] [MeSO 3 ₃ ] shows an external view photograph (Fig. 6 (b)) of a state where IG-IL (Experimental example 2) made from a raw material is placed on a slide glass. As shown in FIG. 6 (a), it was found that in Experimental Example 1, the liquid was almost transparent and operative. On the other hand, as shown in FIG. 6 (b), in Experimental Example 2, it was found to be a white pasty solid.

  Next, TEM observation was performed. FIGS. 7A, 7B, and 7C are diagrams showing TEM observation results of Experimental Example 1, Experimental Example 2, and Experimental Example 3, respectively. In FIG. 7, any IG-IL confirmed a nanotube structure that was partly aggregated in a bundle. From this, it was found that IG was present in the IG-IL (composition) of Experimental Examples 1 to 3 while maintaining the network structure.

3.3. Preparation and Evaluation of Imogolite (IG) -Ionic Liquid (IL) -Bifunctional Compound (DA) Composite IG-131aq. Was mixed with ionic liquid (IL). [EmIm] and [BmIm] [BF ₄ ] were used for IL. In order to remove water from the mixture, evaporation at 60 ° C. for 3 hours and vacuum heat drying at 60 ° C. for 12 hours were performed to obtain a composition (IG-IL) in which IG and IL were uniformly mixed. A dibasic acid (maleic acid (MA) or 4-phosphonobutanoic acid (PBA), both manufactured by Wako Pure Chemical Industries, Ltd.) in which IG-IL is dissolved in IL is mixed, and a gel-like composition (composite) ( IG-IL-DA) was obtained. In addition, except having changed the time of ultrasonic irradiation to 12 hours, IG-50; average length 50nm was created like IG-131.

  The types and blending amounts of IG, IL and DA in each experimental example are shown in Table 2.

FIG. 8 shows that IG-131 [EmIm] [MeSO ₃ ] and IG-IL-DA (Experimental Example 13) made of MA as raw materials are put in a screw vial in a fluidized state and left standing for one hour. And externally photographed when the screw vial is inverted by gently reversing the top and bottom (FIG. 8 (a)), and TEM observation result of IG-IL-DA of the experimental example 13 (FIG. 8 (b)) ).

  As shown to Fig.8 (a), it turned out that IG-IL-DA of Experimental example 13 shows the outstanding reversible gel / sol transition (thixotropic property). Moreover, in FIG.8 (b), the network (network structure) which a nanotube makes was confirmed. From this, the composition of IG-IL-DA is considered that IG forms the network structure in the composition and is gelatinized.

3.4. Measurement of ion conductivity Ion conductivity was measured for the above experimental example. The ionic conductivity was calculated from the complex impedance. The sample was vacuum dried at room temperature for 12 hours before measurement. The measurement was carried out on a sample sandwiched between SUS electrodes in a glove box with a circulation purifier in a dry argon atmosphere using Potentiostat / Galvanostat SP-150 (manufactured by BioLogic). The measurement frequency range was 100 Hz to 1 MHz. Moreover, the measurement temperature measured 7 points | pieces in the range of 30 to 100 degreeC.

FIG. 9 is an Arrhenius plot of the measurement results of ion conductivity in the case of Experiment 1, Experiment 2, and only IL ([EmIm] [MeSO ₃ ]) used therein.

FIG. 10 is an Arrhenius plot of the measurement results of ion conductivity in the case of Experimental Example 3, Experimental Example 5, and only IL ([BmIm] [BF ₄ ]) used in these.

FIG. 11 is an Arrhenius plot of measurement results of ion conductivity in the case of Experimental Example 13, Experimental Example 16, and only IL ([EmIm] [MeSO ₃ ]) used therein.

  As shown in FIGS. 9 to 11, it was found that the composition of each experimental example exhibited high ionic conductivity over a wide temperature range.

Moreover, about each experiment example described in Table 1 and Table 2, regarding IG-IL, the property observation by visual observation is performed, and what became solid (paste) form is A, and although it is a liquid form, the thickening effect is recognized. The IG-IL-DA is shown in each table as IG-IL-DA, where A is clearly observed thixotropy and B is not thixotropy. Furthermore, in each experimental example, those having an ionic conductivity at 30 ° C. of 1 × 10 ⁻³ or more are shown in each table as A and those having an ion conductivity of less than 1 × 10 ⁻³ as B.

  When Table 1 was seen, about any experimental example, it turned out that a thickening effect and favorable ion conductivity are shown. It was also found that the longer the average IG length, the more likely it becomes solid. Moreover, regardless of the type of IL, high ionic conductivity was exhibited, and it was found that such ionic conductivity did not greatly depend on the blending amount of IG. Furthermore, even if there was little content of IG, when the average length was large, it turned out that it can become solid state sufficiently.

Moreover, when Table 2 was seen, about any experimental example, it turned out that favorable ion conductivity is shown. On the other hand, regarding thixotropy, there was no clear correlation with the average length and blending amount of IG, the type and blending amount of DA, and the like. From this, it is considered that thixotropic properties are manifested by the balance between the average length and blending amount of IG, and the type and blending amount of DA. In addition, regarding the ionic conductivity, when the type of IL is [BmIm] [BF ₄ ], there is a tendency that it becomes better with a smaller amount than in the case of [EmIm] [MeSO ₃ ], but [EmIm ] When comparing experimental examples using [MeSO ₃ ], no clear tendency was observed. From this, it is considered that the ion conductivity is also expressed by the balance of the average length and blending amount of IG, the type and blending amount of DA, and the type of IL.

  In the present invention, a part of the configuration may be omitted within a range having the characteristics and effects described in the present application, or each embodiment or modification may be combined. In addition, the invention includes substantially the same configuration (the configuration having the same function, method, and result, or the configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

According to the present invention, a composition useful as an electrolyte material having both “excellent processability derived from thixotropic / solid properties” and “high ionic conductivity derived from an ionic liquid” can be obtained. Therefore, the composition according to the present invention has significant industrial and academic significance. Moreover, the composition according to the present invention can be carried out by a simple process of mixing or drying each component. Therefore, application to a wide range of industrial fields including batteries is expected. Furthermore, since imogolite can be synthesized by thermal polymerization of aluminum chloride and sodium orthosilicate, it can be produced (synthesized) cheaply and easily compared to materials such as carbon nanotubes that are dispersed in an ionic liquid and solidify the ionic liquid. Further, since it is possible to increase the scale of production, this point is also advantageous industrially and industrially.

Claims (9)

Imogolite having an average length of 1 μm to 10 μm;
An ionic liquid,
And a composition having ionic conductivity. In claim 1,
The composition has a shear strain region in which the loss elastic modulus G ″ is smaller than the storage elastic modulus G ′ in the dynamic viscoelasticity measurement. Imogolite having an average length of 50 nm to 10 μm,
An ionic liquid,
A polyfunctional compound;
And a composition having ionic conductivity. In claim 3,
The composition has a shear strain region in which the value of the loss modulus G ″ and the value of the storage modulus G ′ are reversed in the dynamic viscoelasticity measurement. In claim 3 or claim 4,
The composition wherein the polyfunctional compound is a difunctional organic acid. In any one of Claims 3 thru | or 5,
The polyfunctional compound is
A compound having 2 to 6 carbon atoms,
At least one group selected from a carboxyl group, a phosphoric acid group, a phosphoric acid group, a phosphorous acid group, a phosphonic acid group, a sulfonic acid group, and a sulfuric acid group;
At least one group selected from an amino group and a carboxamide group;
A composition comprising: In any one of Claims 3 thru | or 6,
The polyfunctional compound is a composition comprising 0.5% by mass to 4.2% by mass with respect to the total mass. In any one of Claims 1 thru | or 7,
The imogolite is a composition containing 2% by mass to 10% by mass with respect to the total mass. In any one of Claims 1 thru | or 8,
The composition, wherein the ionic liquid is at least one selected from imidazolium salts, pyridinium salts, pyrrolidinium salts, phosphonium salts, ammonium salts, guanidinium salts, isouronium salts, and isothiouronium salts.