JP2018119058A - Polyion complex, electrolyte for electric double-layered capacitor, and electric double-layered capacitor - Google Patents

Abstract

Provided is a polyion complex having excellent ion conductivity. A polyion complex having a polyether compound having a cationic group and a counter anion having two or more monovalent anionic groups in the molecule as a counter anion. In the polyion complex, the polyether compound having a cationic group is preferably composed of a monomer unit represented by the formula (1). (A + is a cationic group or a cationic group-containing group; R is a nonionic group; n is an integer of 2 or more; m is an integer of 0 or more; n + m ≧ 5) [Selection] None

Description

  The present invention relates to a polyion complex having excellent ion conductivity, and an electrolyte for an electric double layer capacitor and an electric double layer capacitor using such a polyion complex.

  In general, a complex salt of a polycation and a polyanion is collectively referred to as a polyion complex. In such a polyion complex, a cation and an anion become multivalent to form a network-like cross-linked structure in which individual ion pairs are covalently bonded, and application in a wide range of technical fields is expected. (For example, refer to Patent Document 1).

  On the other hand, since the polycation complex is a structure in which the polycation and the polyanion tend to inhibit each other's mobility, the ion mobility is generally very low, and therefore, in a bulk state or a solution state Occasionally, its ionic conductivity is very low, which makes it difficult to apply to applications that require ionic conductivity.

JP 2016-37596 A

  The present invention has been made in view of such a situation, and an object thereof is to provide a polyion complex having excellent ion conductivity. Another object of the present invention is to provide an electrolyte for an electric double layer capacitor and an electric double layer capacitor using such a polyion complex.

  As a result of intensive studies to achieve the above object, the present inventors have found that a polyether compound having a cationic group and a counter anion having two or more monovalent anionic groups in the molecule as a counter anion. It has been found that the polyion complex has excellent ionic conductivity, and the present invention has been completed.

（上記一般式（１）中、Ａ^＋は、カチオン性基またはカチオン性基含有基を表し、Ｒは非イオン性基を表し、ｎは２以上の整数であり、ｍは０以上の整数であり、ｎ＋ｍは５以上の整数である。） That is, according to the present invention, there is provided a polyion complex having a polyether compound having a cationic group and a counter anion having two or more monovalent anionic groups in the molecule as a counter anion.
In the polyion complex of the present invention, the polyether compound having a cationic group is preferably composed of a monomer unit represented by the following general formula (1).

(In the above general formula (1), A ⁺ represents a cationic group or a cationic group-containing group, R represents a nonionic group, n is an integer of 2 or more, and m is an integer of 0 or more. And n + m is an integer of 5 or more.)

Moreover, according to this invention, the electrolyte for electric double layer capacitors containing said polyion complex is provided.
Furthermore, according to this invention, an electrical double layer capacitor provided with said electrolyte for electrical double layer capacitors is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the electrolyte for electric double layer capacitors and electric double layer capacitor which use a polyion complex excellent in ion conductivity, and such a polyion complex can be provided.

<Polyion complex>
The polyion complex of the present invention is a complex salt of a polycation and a polyanion having a polyether compound having a cationic group and a counter anion having two or more monovalent anionic groups in the molecule as a counter anion. is there.
The polyion complex of the present invention may form a complex salt in the molecule of a polyether compound having a cationic group, or may form a complex salt between molecules of a polyether compound having a cationic group. May be. In addition, a complex salt may be formed both within and between the molecules of the polyether compound having a cationic group.

  The polyether compound having a cationic group used in the present invention is a polymer comprising an oxirane monomer unit as a main chain, which is a unit obtained by ring-opening polymerization of an oxirane structure portion of a compound containing an oxirane structure. An ether compound having a cationic group in its molecule.

  Specific examples of the oxirane monomer unit that forms the polyether compound having a cationic group used in the present invention include alkylene oxide monomer units such as ethylene oxide units, propylene oxide units, and 1,2-butylene oxide units; Epihalohydrin monomer units such as epichlorohydrin units, epibromohydrin units, epiiodohydrin units; alkenyl group-containing oxirane monomer units such as allyl glycidyl ether units; aromatic ether groups such as phenyl glycidyl ether units Examples thereof include, but are not limited to, containing oxirane monomer units; (meth) acryloyl group-containing oxirane monomer units such as glycidyl acrylate units and glycidyl methacrylate units.

  The polyether compound having a cationic group used in the present invention may contain two or more oxirane monomer units. In this case, the distribution pattern of the plurality of repeating units is not particularly limited. However, it is preferable to have a random distribution.

  Among the above monomer units, the epihalohydrin monomer unit, the alkenyl group-containing oxirane monomer unit, and the (meth) acryloyl group-containing oxirane monomer unit are oxirane monomer units having a crosslinkable group. Yes, by containing an oxirane monomer unit having such a crosslinkable group, in the polyether compound having a cationic group used in the present invention, a crosslinkable group can be introduced in addition to the cationic group, In this case, a polyether compound having a cationic group can be crosslinked by using a combination of crosslinking agents. In this case, the ratio of the oxirane monomer unit having a crosslinkable group can be any ratio. The oxirane monomer unit having a crosslinkable group may be a monomer unit having a crosslinkable group, and is not particularly limited to those described above. Further, in the oxirane monomer unit constituting the polyether compound having a cationic group, the cationic group and the crosslinkable group may be contained as the same repeating unit or as separate repeating units. However, it is preferably contained as a separate repeating unit.

  The polyether compound having a cationic group used in the present invention contains an oxirane monomer unit having a cationic group as at least a part of the oxirane monomer unit.

  Although it does not specifically limit as a cationic group which can be contained in the polyether compound which has a cationic group used by this invention, From a viewpoint that the ionic conductivity as a polyion complex can be improved more, it is a periodic table 15th. The group or group 16 atom is preferably a cationic group having an onium cation structure, and the nitrogen atom is more preferably a cationic group having an onium cation structure.

  Specific examples of the cationic group include ammonium group, methylammonium group, butylammonium group, cyclohexylammonium group, anilinium group, benzylammonium group, ethanolammonium group, dimethylammonium group, diethylammonium group, dibutylammonium group, and nonylphenylammonium. Group, trimethylammonium group, triethylammonium group, n-butyldimethylammonium group, n-octyldimethylammonium group, n-stearyldimethylammonium group, tributylammonium group, trivinylammonium group, triethanolammonium group, N, N-dimethyl Ammonium groups such as ethanolammonium group and tri (2-ethoxyethyl) ammonium group; piperidinium group, 1-pyrrolidinium Group, 1-methylpyrrolidinium group, imidazolium group, 1-methylimidazolium group, 1-ethylimidazolium group, benzimidazolium group, pyrrolium group, 1-methylpyrrolium group, oxazolium group, benzoxazolium group Group, benzisoxazolium group, pyrazolium group, isoxazolium group, pyridinium group, 2,6-dimethylpyridinium group, pyrazinium group, pyrimidinium group, pyridazinium group, triazinium group, N, N-dimethylanilinium group, A group comprising a heterocyclic ring containing a cationic nitrogen atom such as quinolinium group, isoquinolinium group, indolinium group, isoindolinium group, quinoxalium group, isoquinoxalium group, thiazolium group; triphenylphosphonium salt, tributyl Phosphonium group, etc. Groups comprising a cationic phosphorus atom; but like, but is not limited thereto. Among these, 1-methylpyrrolidinium group, trimethylammonium group, n-butyldimethylammonium group, imidazolium group, 1-methylimidazolium group, 1-ethylimidazolium group, benzimidazolium group, pyridinium group, 2 A 6-dimethylpyridinium group or the like is preferable. In the polyether compound having a cationic group used in the present invention, all the cationic groups contained may be the same, or an embodiment containing two or more different groups may be used. .

  Further, in the polyether compound having a cationic group used in the present invention, it is sufficient that at least a part of the oxirane monomer units constituting the polyether compound is an oxirane monomer unit having a cationic group. For example, all of the oxirane monomer units constituting the polyether compound may have a cationic group, or the oxirane monomer unit having a cationic group and the oxirane unit having no cationic group. There may be a mixture of unit units. In the polyether compound having a cationic group used in the present invention, the proportion of the oxirane monomer unit having a cationic group is not particularly limited, and the oxirane monomer unit constituting the polyether compound having a cationic group 1 mol% or more is preferable with respect to the whole, 10 mol% or more is more preferable, and 30 mol% or more is especially preferable. In addition, the upper limit of the ratio for which the oxirane monomer unit which has a cationic group accounts is not specifically limited. By setting the ratio of the oxirane monomer unit having a cationic group to the above range, the ionic conductivity as the polyion complex can be more appropriately increased.

（上記一般式（１）中、Ａ^＋は、カチオン性基またはカチオン性基含有基を表し、Ｒは非イオン性基を表し、ｎは２以上の整数であり、ｍは０以上の整数であり、ｎ＋ｍは５以上の整数である。） Although it does not specifically limit as a structure of the polyether compound which has a cationic group used by this invention, It is preferable that it is what consists of a monomer unit represented by following General formula (1).

(In the above general formula (1), A ⁺ represents a cationic group or a cationic group-containing group, R represents a nonionic group, n is an integer of 2 or more, and m is an integer of 0 or more. And n + m is an integer of 5 or more.)

In the general formula (1), A ⁺ represents a cationic group or a cationic group-containing group, and specific examples of the cationic group include those described above. As the cationic group-containing group, The group containing the cationic group mentioned above is mentioned. In the above general formula (1), the cationic groups or the cationic group-containing groups represented by A ⁺ may all be the same, or may contain two or more different groups. There may be.

In the general formula (1), R is a nonionic group and is not particularly limited as long as it is a nonionic group.
R is, for example, a hydrogen atom; an alkyl group having 1 to 10 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a t-butyl group; a vinyl group or an allyl group. Group, alkenyl group having 2 to 10 carbon atoms such as propenyl group; alkynyl group having 2 to 10 carbon atoms such as ethynyl group and propynyl group; 3 to 20 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group A C6-C20 aryl group such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group;
Moreover, among these, a C1-C10 alkyl group, a C2-C10 alkenyl group, a C2-C10 alkynyl group, a C3-C20 cycloalkyl group, and a C6-C20 The aryl group may have a substituent at any position.

  Examples of the substituent include an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an ethoxy group and an isopropoxy group; and a carbon number such as a vinyloxy group and an allyloxy group. 2-6 alkenyloxy groups; aryl groups optionally having substituents such as phenyl group, 4-methylphenyl group, 2-chlorophenyl group, 3-methoxyphenyl group; fluorine atom, chlorine atom, bromine atom, etc. Halogen atoms of 1 to 6 carbon atoms such as methylcarbonyl group and ethylcarbonyl group; (meth) acryloyloxy groups such as acryloyloxy group and methacryloyloxy group; and the like. In the general formula (1), all of the nonionic groups represented by R may be the same, or may be an embodiment containing two or more different groups.

  In the general formula (1), n is an integer of 2 or more, and m may be an integer of 0 or more. However, n is preferably an integer of 2 to 500, and an integer of 2 to 300. Is more preferable, and an integer of 3 to 150 is more preferable. M is preferably an integer of 0 to 498, more preferably an integer of 0 to 298, and still more preferably an integer of 0 to 147. N + m is an integer of 5 or more, preferably an integer of 5 to 500, more preferably an integer of 5 to 300, and still more preferably an integer of 5 to 150. By appropriately adjusting n, m, and n + m in the general formula (1), the ion conductivity as the polyion complex can be more appropriately increased.

  In addition, when the structure of the polyether compound having a cationic group used in the present invention is a monomer unit represented by the general formula (1), the polymer chain end is not particularly limited, It can be any group. Examples of the polymer chain end group include the above-described cationic group, hydroxyl group, or hydrogen atom.

  Further, the counter anion having two or more monovalent anionic groups in the molecule used in the present invention is a counter anion of the above-described polyether compound having a cationic group, and the monovalent anionic group is An anion having two or more in the molecule. The counter anion having two or more monovalent anionic groups in the molecule used in the present invention is one having two or more monovalent anionic groups in one molecule. Although it becomes a valent anion, it has a structure in which a plurality of negatively charged monovalent groups exist at different positions in the molecule. In the anion having two or more monovalent anionic groups in the molecule used in the present invention, such negatively charged monovalent groups (monovalent anionic groups) are usually directly It has a structure bonded through a covalent bond, or a structure bonded through another bonding group.

The monovalent anionic group constituting the counter anion having two or more monovalent anionic groups in the molecule is not particularly limited as long as it is a negatively charged monovalent group. However, examples include anionic groups derived from conjugate acids such as sulfonylimide groups, sulfonic acid groups, carboxyl groups, and hydroxyl groups. The anionic group derived from a sulfonyl imide ^{_{group, - (SO 2) N -}} (SO 2) -, - (SO 2) N - (SO 2 CF 3), - (SO 2) N - (SO 2 F ^{_{), - (SO 2) N}} - (SO 2 CF 2 CF 3) , and the like. The anionic group derived from a sulfonic acid ^{_{group, -CF 2 SO 3 -, -CH}} 2 SO 3 -, -PhSO 3 - and the like. The anionic group derived from a carboxyl ^{_{group, -CF 2 COO -, -CH 2}} COO -, -PhCOO - and the like. The anionic group derived from a hydroxyl ^{_{group, -CF 2 O -, -CH 2}} O - , and the like.

Specific examples of the counter anion having two or more within a monovalent anionic group ^{_{molecule, - O 3 SCF 2 CF 2}} CF 2 SO 3 -, - O 3 SCF 2 CF 2 SO 3 -, CF 3 SO 2 ^{_{N - SO 2 CF 2 CF 2}} OCF 2 CF 2 OCF 2 CF 2 SO 2 N - SO 2 CF 3, poly ^{_{(CH 2 = CHCOO -),}} CF 3 SO 2 N - SO 2 CF 2 CF 2 OCF 2 CF 2 ^{_{OCF 2 CF 2 SO 2 N -}} SO 2 CF 2 CF 2 OCF 2 CF 2 OCF 2 CF 2 SO 2 N - CF 2 CF 2 OCF 2 CF 2 OCF 2 CF 2 SO 2 N - SO 2 CF 3, poly (CH ^{_{2 = CHPh-SO 2 N -}} SO 2 CF 3), poly ^{_{(CH 2 = CHCOO-SO 2}} N - SO 2 CF 3) , and the like.

On the other hand, although sulfate ion (SO ₄ ²⁻ ) and carbonate ion (CO ₃ ²⁻ ) are polyvalent anions, they are anions having one divalent anionic group in the molecule. It does not correspond to a counter anion having two or more monovalent anionic groups in the molecule.

  The polyion complex of the present invention only needs to contain a counter anion having two or more monovalent anionic groups in the molecule as the counter anion of the cationic group of the polyether compound having a cationic group. In the range where the effects of the present invention are not impaired, a counter anion other than the counter anion having two or more monovalent anionic groups in the molecule may be contained. However, from the viewpoint of realizing excellent ion conductivity, the ratio of the counter anion having two or more monovalent anionic groups in the molecule to the entire counter anion is preferably 10 mol% or more, and more It is preferably 50 mol% or more, and it is particularly preferable that all counter anions are counter anions having two or more monovalent anionic groups in the molecule.

The production method of the polyion complex of the present invention is not particularly limited, and any production method can be adopted as long as the target complex salt can be obtained. As an example of the production method, first, a base polymer (polyether compound having no cationic group) is obtained by the following method (A) or (B).
(A) A monomer containing an oxirane monomer including at least an epihalohydrin such as epichlorohydrin, epibromohydrin, epiiodohydrin, etc. is disclosed in JP 2010-53217 A as a catalyst. In the presence of a catalyst comprising an onium salt of a compound containing a group 15 or 16 atom of the periodic table and a trialkylaluminum in which all of the alkyl groups contained are linear alkyl groups. A method of obtaining a base polymer by ring-opening polymerization.
(B) A monomer containing an oxirane monomer including at least an epihalohydrin such as epichlorohydrin, epibromohydrin, epiiodohydrin, etc. is disclosed in JP-B-46-27534. A method for obtaining a base polymer by ring-opening polymerization in the presence of a catalyst obtained by reacting phosphoric acid and triethylamine with isobutylaluminum.

  Then, by reacting the base polymer obtained in the above method (A) or (B) with an amine compound such as an imidazole compound, the halogen group constituting the epihalohydrin monomer unit of the base polymer is converted into an onium halide group. By converting, a polyether compound having a cationic group (a polyether compound having an onium halide group composed of a cationic group and a halide ion) is obtained, and then halide ions are converted by anion exchange reaction. A polyion complex can be obtained by converting it into an anion having two or more monovalent anionic groups in the molecule.

  Since the polyion complex of the present invention has a polyether compound having a cationic group and a counter anion having two or more monovalent anionic groups in the molecule as a counter anion, it has excellent ion conductivity. Therefore, taking advantage of such characteristics, it can be suitably used for various applications such as an electrolyte application for an electric double layer capacitor described later. In particular, when the polyion complex of the present invention is used as an electrolyte for an electric double layer capacitor, it can act as an electrolyte for an electric double layer capacitor due to its excellent ionic conductivity. Capacitance (capacitance) as a capacitor can be improved, and therefore, it can be suitably used as an electrolyte for an electric double layer capacitor.

<Electrolyte for electric double layer capacitor>
The electrolyte for an electric double layer capacitor of the present invention contains the above-described polyion complex of the present invention. The electrolyte for an electric double layer capacitor of the present invention may be composed of only the polyion complex of the present invention (that is, 100% by weight of the polyion complex of the present invention) or other than the polyion complex of the present invention. These components may be included.

  Components other than the polyion complex of the present invention are not particularly limited, but water, methanol, ethanol, toluene, acetone, tetrahydrofuran, ethylene carbonate, propylene carbonate, dimethyl carbonate, vinylene carbonate, ethyl methyl carbonate, diethyl carbonate, γ-butyrolactone Solvents such as; ionic liquids such as ethylmethylimidazolium tetrafluoroborate, ethylmethylimidazolium bistrifluoromethanesulfonylimide, trimethylethylammonium tetrafluoroborate; nanocarbons such as carbon nanotubes, graphite, graphene, graphene oxide; zinc oxide, Metal oxynitrides such as magnesium oxide, boron nitride, gallium nitride; But it is not limited thereto. Among these, a solvent and an ionic liquid are preferable because the ion conductivity of the electrolyte of the present invention can be appropriately increased.

  In the electrolyte for an electric double layer capacitor of the present invention when the electrolyte for an electric double layer capacitor of the present invention contains other components such as a solvent and an ionic liquid in addition to the polyion complex of the present invention described above. In the polyion complex, the content of the polyion complex is a molar concentration of the cationic group in the polyion complex, preferably 0.1 to 5.0 mol / L, more preferably 0.3 to 4.0 mol / L, still more preferably. Is 0.5 to 3.0 mol / L. By setting the content of the polyion complex in the above range, the ionic conductivity of the electrolyte of the present invention can be increased more appropriately, and thus, when applied to an electric double layer capacitor, the electric double layer capacitor obtained can be obtained. The output can be further increased.

  Moreover, when using what has a crosslinkable group as a polyether compound which has a cationic group which comprises the polyion complex contained in the electrolyte for electric double layer capacitors, in the electrolyte for electric double layer capacitors, a crosslinking agent It is good also as what was set as the crosslinkable composition by making it contain and bridge | crosslinked this.

  What is necessary is just to select suitably as a crosslinking agent according to the kind etc. of the crosslinkable group which the polyether compound which has a cationic group has. Specific examples of the crosslinking agent include organic peroxides such as dicumyl peroxide and ditertiarybutyl peroxide; quinone dioximes such as p-quinone dioxime and p, p'-dibenzoylquinone dioxime; triethylenetetramine and hexa Organic polyamine compounds such as methylenediamine carbamate and 4,4′-methylenebis-o-chloroaniline; triazine compounds such as s-triazine-2,4,6-trithiol; alkylphenol resin having a methylol group; 2-methyl -1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl ] Various ultraviolet rays such as alkylphenone type photopolymerization initiators such as 1-butanone Bridge agent; and the like. For example, when the crosslinkable group of the polyether compound having a cationic group is an ethylenic carbon-carbon unsaturated bond-containing group, the organic peroxide and the ultraviolet crosslinking agent are selected from the above crosslinking agents. It is preferable to use a crosslinking agent, and it is particularly preferable to use an ultraviolet crosslinking agent. These crosslinking agents can be used alone or in combination of two or more. Although the compounding quantity of a crosslinking agent is not specifically limited, Preferably it is 0.1-10 weight part with respect to 100 weight part of polyion complexes, More preferably, 0.2-7 weight part is more preferable, More preferably, it is 0.8. 3 to 5 parts by weight. By making the compounding quantity of a crosslinking agent into the said range, it can bridge | crosslink appropriately, maintaining ion conductivity favorable. In addition, it does not specifically limit as a method for bridge | crosslinking, Arbitrary methods are employable according to the kind etc. of the crosslinking agent to be used.

<Electric double layer capacitor>
The electric double layer capacitor of the present invention contains the above-described electrolyte for electric double layer capacitors of the present invention. The configuration of the electric double layer capacitor of the present invention is not particularly limited. For example, the capacitor element including a pair of polarizable electrodes and a separator interposed between the polarizable electrodes, and the electric double layer of the present invention described above. The thing provided with the electrolyte for capacitors is mentioned.

As the polarizable electrode, for example, an electrode obtained by forming a polarizable electrode layer containing a carbonaceous material and a binder on a current collector can be used. The carbonaceous material is not particularly limited, and activated carbon is generally used. Examples of the activated carbon include powders such as phenols, pitches, and polyacrylonitriles, or fibers, and those having a specific surface area of 1000 m ² / g or more are preferable.

  The separator is not particularly limited as long as it can insulate between polarizable electrodes. Specifically, polyolefins such as polyethylene and polypropylene, microporous membranes or nonwoven fabrics made of rayon or glass fiber, and porous membranes mainly made of pulp called electrolytic capacitor paper can be used. Although the thickness of a separator is suitably selected according to a use purpose, it is 1-100 micrometers normally, Preferably it is 10-80 micrometers, More preferably, it is 20-60 micrometers.

  The electric double layer capacitor of the present invention is obtained by, for example, impregnating the above-described electrolyte for an electric double layer capacitor of the present invention into a capacitor element composed of a pair of polarizable electrodes and a separator interposed between the polarizable electrodes. Can be manufactured. Specifically, a capacitor element composed of a pair of polarizable electrodes and a separator interposed between the polarizable electrodes is placed in a container by winding, stacking, or folding as necessary, and the book described above in the container. It can be manufactured by injecting the electrolyte for an electric double layer capacitor of the invention, impregnating it under reduced pressure as required, and then sealing. Alternatively, it can also be produced by storing a capacitor element impregnated with the above-described electrolyte for electric double layer capacitor of the present invention in a container. Any known container such as a coin shape, a cylindrical shape, a square shape, or a laminate shape can be used as the container.

  Since the electric double layer capacitor of the present invention includes the above-described electrolyte for an electric double layer capacitor containing the polyion complex of the present invention, the electric double layer capacitor is good as an electric double layer capacitor due to the high ion conductivity of the polyion complex of the present invention. In addition, a high capacitance can be realized. Therefore, taking advantage of such characteristics, it can be suitably used for various applications such as power storage applications such as automobiles and construction machinery, and circuit drive applications such as personal computers and smartphones.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples. In the following, “part” is based on weight unless otherwise specified. Moreover, the test and evaluation followed the following.

(1) Number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)
The number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the base polymer (polyether compound having no cationic group) were determined by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent. It was measured as a polystyrene equivalent value. In addition, HLC-8320 (manufactured by Tosoh Corp.) is used as a measuring device, four TSKgel SuperMultipore HZ-H (manufactured by Tosoh Corp.) are connected in series, and a detector is a differential refractometer RI-8320 (Tosoh Corp. Made).

(2) Structure of the polyether compound having a cationic group and the content of the oxirane monomer unit having a cationic group in the polyether compound having a cationic group Structure of the polyether compound having a cationic group, and The content of the oxirane monomer unit having a cationic group was measured as follows using a nuclear magnetic resonance apparatus (NMR). That is, first, 30 mg of a polyether compound having a cationic group as a sample was added to 1.0 mL of heavy dimethyl sulfoxide and shaken for 1 hour to be uniformly dissolved. And the NMR measurement was performed about the obtained solution, the < ¹ > H-NMR spectrum was obtained, and the structure of the polyether compound was assigned according to the usual method.
Moreover, the content rate of the oxirane monomer unit which has a cationic group in the polyether compound which has a cationic group was computed with the following method. That is, first, the number of moles B1 of all oxirane monomer units was calculated from the integral value of protons derived from the main chain oxirane monomer units. Next, the number of moles B2 of the oxirane monomer unit having a cationic group was calculated from the integral value of protons derived from the cationic group. And the ratio (percentage) of B2 with respect to B1 was calculated | required as content rate of the oxirane monomer unit which has a cationic group in the polyether compound which has a cationic group.

(3) Electrochemical measurement of electrolyte for electric double layer capacitor As working electrode, platinum electrode (BAS PTE platinum electrode outer diameter 6 mm, inner diameter 3 mm), and reference electrode, Ag / AgCl electrode (BAS RE-7 non-aqueous) Solvent system reference electrode (Ag / AgCl)) as counter electrode, platinum (BAS Co., Ltd., Pt counter electrode, 5 cm electrode, electrode diameter 0.5 mm), respectively, for the electrolyte for electric double layer capacitor, Cyclic voltammetry measurement was performed. For measurement, "solartron 1281 Multiplexer" (manufactured by Toyo Technica) and "solartron 1281 Electrochemical Interface" (manufactured by Toyo Technica) were used. All measurements were performed in a circulating glove box filled with dry nitrogen.

[Production Example 1]
(Living anionic polymerization of epichlorohydrin)
To a glass reactor equipped with a stirrer substituted with argon, 0.322 g of tetranormalbutylammonium bromide and 5 ml of toluene were added and cooled to 0 ° C. Next, 0.137 g of triethylaluminum (1.2 molar equivalent to tetranormalbutylammonium bromide) dissolved in 0.5 ml of normal hexane was added and reacted for 15 minutes to obtain a catalyst composition. . And 10.0 g of epichlorohydrin was added to the obtained catalyst composition, and a polymerization reaction was performed at 0 ° C. After the polymerization reaction started, the viscosity of the solution gradually increased. After reacting for 1 hour, a small amount of 2-propanol was added to the polymerization reaction solution to stop the reaction. The obtained polymerization reaction liquid was diluted with toluene and then poured into 2-propanol to obtain a white rubbery substance with a yield of 11.9 g. Moreover, the number average molecular weight (Mn) by GPC of the obtained rubber-like substance was 10,300, and molecular weight distribution (Mw / Mn) was 1.20. Further, ¹ H-NMR measurement was performed on the obtained rubber-like substance, and it was confirmed that this rubber-like substance was composed of a repeating unit in which epichlorohydrin was opened. From the above, it can be said that the obtained rubber-like substance is a polymer composed of epichlorohydrin units (degree of polymerization = 110; on average, 110-mer of epichlorohydrin units).

[Production Example 2]
(Quaternization of epichlorohydrin unit in polymer with 1-methylimidazole)
8.0 g of the polymer obtained in Preparation Example 1, 22.0 g of 1-methylimidazole, and 16.0 g of N, N-dimethylformamide were added to a glass reactor equipped with a stirrer replaced with argon, and the mixture was heated to 80 ° C. The reaction was started by heating. After reacting at 80 ° C. for 144 hours, the reaction was stopped by cooling to room temperature. A part of the obtained reaction solution was extracted and dried under reduced pressure at 50 ° C. for 120 hours to obtain a reddish brown resinous substance in a yield of 15.0 g. ¹ H-NMR measurement was performed on this resinous substance, and ¹ H-NMR (DMSO-d6) δ = 9.80-9.40 (brs, 1H, MeIm +), 8.10-7.70 ( _{brs, 2H, MeIm +),} 4.80-3.75 (brs, -CH 2 CH (CH 2 R) O -), a 3.63 (3H, MeIm +), from the area ratio of the proton, the starting material It was identified as poly (methylglycidylimidazolium chloride) in which chloro groups in all epichlorohydrin units in the polymer obtained in Production Example 1 were substituted with 1-methylimidazolium chloride groups. When elemental analysis was performed, the composition ratio of each element was in good agreement with the composition ratio predicted from the structure. From the above, it was identified as a polyether compound having a 1-methylimidazolium chloride group and a polymerization degree of 110.

[Example 1]
(Anion exchange of polyether compound having 1-methylimidazolium chloride group with bislithium (hexafluoropropenyl bissulfonate))
30 ml of distilled water in which 0.92 g of bislithium (hexafluoropropenyl bissulfonate) (LiO ₃ SCF ₂ CF ₂ CF ₂ SO ₃ ) Li was dissolved was added to a glass reactor equipped with a stirrer. Next, 1.0 g of the polyether compound having 1-methylimidazolium chloride group obtained in Production Example 2 was dissolved in 10 ml of distilled water, dropped into a glass reactor and reacted at room temperature for 30 minutes. After the reaction, the precipitated viscous water-like substance was collected and washed repeatedly with 10 ml of distilled water to remove inorganic salts. When the water-like substance obtained by coagulation was dried under reduced pressure at 50 ° C. for 12 hours, a colorless and transparent glassy substance was obtained in a yield of 1.5 g. When the obtained glassy substance was subjected to ¹ H-NMR measurement, ¹ H-NMR (DMSO-d6) δ = 8.80-9.00 (brs, 1H, MeIm +), 7.50-7. _{80 (brs, 2H, MeIm +} ), 4.50-3.20 (brs, -CH 2 CH (CH 2 R) O -), 3.90 (3H, MeIm +) is, as a starting material production example 2 all of chloride ions of 1-methylimidazolium chloride groups in the repeating units of the polyether compound having obtained 1-methyl imidazolium chloride group is hexafluoro propenyl bis sulfonate dianion ^(- O ₃ SCF ₂ CF ₂ CF ₂ SO 3 ^_-) is replaced with, having a hexafluoropropylene propenyl bis sulfonate dianion as a counter anion, the degree of polymerization = 110 poly It was identified to be on complex A. When elemental analysis was performed, the composition ratio of each element was in good agreement with the composition ratio predicted from the structure.

[Example 2]
By mixing the polyion complex A obtained in Example 1 with propylene carbonate so that the molar concentration of the cationic group is 1.0 mol / L, a transparent composition (electrolyte for electric double layer capacitor) Got. The obtained composition was subjected to electrochemical measurement in the above-described measurement system in a dry nitrogen atmosphere at 23 ° C. Specifically, when a potential of −0.75 V was applied to the platinum electrode of the working electrode with respect to the Ag / AgCl electrode as the reference electrode, and the capacitance on the working electrode was measured, the capacitance at saturation was 15 μF / cm. ² . On the other hand, when a potential of +0.75 V was applied to the platinum electrode of the working electrode with respect to the Ag / AgCl electrode as the reference electrode, and the capacitance on the working electrode was measured, the capacitance at saturation was 18 μF / cm ² . .

[Comparative Example 1]
Ethylmethylimidazolium trifluoromethylsulfonate is mixed with propylene carbonate so that the molar concentration of the ionic group is 1.0 mol / L to obtain a transparent composition (electrolyte for electric double layer capacitor). It was. The obtained composition was subjected to electrochemical measurement in the above-described measurement system in a dry nitrogen atmosphere at 23 ° C. Specifically, when a potential of −0.75 V was applied to the platinum electrode of the working electrode with respect to the Ag / AgCl electrode as the reference electrode, and the capacitance on the working electrode was measured, the capacitance at saturation was 8 μF / cm. ² . On the other hand, when a potential of +0.75 V was applied to the platinum electrode of the working electrode with respect to the Ag / AgCl electrode as the reference electrode, and the capacitance on the working electrode was measured, the capacitance at saturation was 8 μF / cm ² . .

[Evaluation]
As described above, from the results of Example 2 and Comparative Example 1, a polyion complex having a polyether compound having a cationic group and a counter anion having two or more monovalent anionic groups in the molecule as a counter anion, When used as an electrolyte for an electric double layer capacitor, the electric double layer capacitor can be operated satisfactorily, and its excellent ionic conductivity was shown. Moreover, the effect of increasing the capacitance of both the cathode and anode of the electric double layer capacitor was also confirmed.

Claims (4)

  A polyion complex having a polyether compound having a cationic group and a counter anion having two or more monovalent anionic groups in the molecule as a counter anion. The polyion complex according to claim 1, wherein the polyether compound having a cationic group comprises a monomer unit represented by the following general formula (1).

(In the above general formula (1), A ⁺ represents a cationic group or a cationic group-containing group, R represents a nonionic group, n is an integer of 2 or more, and m is an integer of 0 or more. And n + m is an integer of 5 or more.)   The electrolyte for electric double layer capacitors containing the polyion complex of Claim 1 or 2.   An electric double layer capacitor comprising the electrolyte for an electric double layer capacitor according to claim 3.