JP2007163865A - Electrochemical display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical display element facilitating manufacture and superior in durability without causing secondary trouble such as decomposition/degradation of a constituent material by solving the issues in conventional electrochemical display elements using liquid electrolytes. <P>SOLUTION: The electrochemical display element includes a pair of electrodes and at least the electrolyte between the pair of electrodes, wherein the electrolyte is a gel or solid electrolyte cured by heat by a chemical crosslinking agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrochemical display element using an electrolyte such as an electrochromic method or an electric field deposition method, and specifically to an electrochemical display device using a gel electrolyte or a solid electrolyte.

  An electrochromic (hereinafter, also referred to as “EC”) display element is used in so-called ECD (Electrochromic Display), and is an oxidation that occurs on or near an electrode surface by applying a voltage to an electrochromic active material. Applying a so-called electrochromism phenomenon in which the color and light transmittance reversibly change due to the reduction reaction, a voltage is applied between the display electrode that performs the electrochromism operation and the counter electrode, and the voltage is controlled by controlling the applied voltage. Repeated erasing. The electrolytic deposition display element repeats fading due to the electrochromism phenomenon associated with the reduction deposition (colored state) of metal ions and the oxidative dissolution (decolored state) of the deposited metal. Belongs to the scheme. ECD is a liquid crystal display that is generally used as a panel display that has a small viewing angle dependency, a high contrast, a reflective display that is kind to the eyes, a simple element configuration and low cost. There is no advantage, and many studies have been conducted as a next-generation display element (for example, see Patent Document 1).

  Electrochemical display elements (electrochemical display elements) that use electrolytes such as the electrochromic method and the field deposition method generally use liquids as the electrolyte, and the internal pressure rises at high temperatures, causing rupture or harmful. There were major practical problems such as leakage of the electrolyte solution, volatilization of the electrolyte with time / heating, and deterioration of the characteristics.

  In order to solve this problem, measures for gelling the electrolyte have been studied (see, for example, Patent Document, Appendix 2). However, the physical cross-link type shown here is liquefied in a high temperature environment. The problem is not solved. On the other hand, an ultraviolet (UV) chemical cross-linking type is also widely used for lithium ion batteries, which are similarly uses of an electrolyte. However, when this is used as an electrolyte of an electrochemical display element, the cross-linking reaction is performed. As a result of the UV irradiation, a secondary obstacle occurs in which the electrochromic active substance or the like is decomposed / degraded.

In addition to the physical crosslinking type or the UV chemical crosslinking type, there is a thermochemical crosslinking (thermosetting) type gel electrolyte, but there is no example in which this was actually applied to an electrochemical display device to verify the practicality. .
As described above, an electrochemical display element in which problems such as liquid leakage at the time of breakage are eliminated without causing secondary troubles such as decomposition / deterioration of constituent materials has not yet been obtained.
JP 2000-506629 A JP 2001-167629 A

The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, the present invention solves the problems of conventional electrochemical display elements using liquid electrolytes, and is easy to manufacture and excellent in durability without causing secondary obstacles such as decomposition / deterioration of constituent materials. An object is to provide an electrochemical display element.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> An electrochemical display element having a pair of electrodes, including at least an electrolyte between the pair of electrodes, wherein the electrolyte is a gel electrolyte or a solid electrolyte thermally cured by a chemical crosslinking agent.

<2> The electrochemical display device according to <1>, wherein the chemical crosslinking agent includes a compound having two or more hydroxyl groups at a terminal and a compound having two or more isocyanate groups.

<3> The electrochemical display device according to <2>, wherein the compound having two or more hydroxyl groups at the terminal is an oligoalkylene glycol derivative including a structure represented by the following general formula (1).
Formula ^{(1): - (CR 1} R 2 -CR 3 R 4 -O) n H

In general formula (1), R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a hetero atom-containing hydrocarbon group, and n is an integer of 2 to 10 To express.

<4> The electrochemical display device according to <1>, wherein the chemical crosslinking agent includes a compound having two or more nitrogen-containing groups and a compound having two or more electrophilic substituents.

<5> The electrochemical display device according to <4>, wherein the compound having two or more nitrogen-containing groups is represented by the following general formula (2).

  In the general formula (2), Z represents a nitrogen-containing heterocyclic group, L represents an organic group, p1 represents the number of the nitrogen-containing heterocyclic group bonded to the organic group L, and is an integer of 2 to 8. is there.

<6> The electrochemical display device according to <4>, wherein the compound having two or more electrophilic substituents is represented by the following general formula (3).

  In the general formula (3), Y represents an electrophilic substituent, L ′ represents an organic group, p2 represents the number of the electrophilic substituent bonded to the organic group L ′, It is an integer.

  <7> The electrochemical display element according to <4>, wherein the electrophilic substituent is at least one selected from a halogen atom, an acyloxy group, and a sulfonyloxy group.

<8> The electrochemical display element according to <1>, wherein a porous layer having a roughness coefficient in the range of 10 to 2000 is provided on at least one surface of the pair of electrodes.

<9> The electrochemical display device according to <8>, wherein an electrochromic active substance is provided on a surface of the porous layer.

<10> The electrochemical display device according to <1>, wherein a white separator that can be impregnated and permeated with an electrolyte is provided between the pair of electrodes.

  The present invention solves the problems of conventional electrochemical display elements using liquid electrolytes, and is easy to manufacture and excellent in durability without causing secondary obstacles such as decomposition / deterioration of constituent materials. An electrochemical display element can be provided.

Hereinafter, the present invention will be described in detail.
The electrochemical display element of the present invention has a pair of electrodes, includes at least an electrolyte between the pair of electrodes, and the electrolyte is a gel electrolyte or a solid electrolyte thermally cured by a chemical crosslinking agent.

  Since the electrochemical display element of the present invention uses a gel electrolyte or a solid electrolyte which is thermoset as the electrolyte, the electrolyte is not liquefied even when the element is left in a high temperature environment, and the volatilization or internal pressure of the electrolyte solution is prevented. The rise problem can be suppressed to a level where there is no practical problem. Also, when manufacturing an electrochemical display element, as will be described later, an electrolyte material is sealed between a pair of electrodes and cured at a relatively low temperature, so that an EC active substance or the like is not decomposed / deteriorated. The above points are also excellent.

In electrochemical display elements, substances that inhibit electrochemical reactions associated with electrochromism, substances that cause unwanted chemical reactions with the redox state of electrochromic active substances, and unwanted electrochemical reactions. If there is a substance that suffers from the loss, the efficiency of the decoloring reaction decreases, the repeated stability of the decoloring reaction decreases, the power consumption as ECD increases, the gas is generated and an image defect occurs, or the device When the electrolyte is chemically gelled or solidified, in addition to the characteristics of the gelling agent / solidifying agent itself used, the secondary agent associated with the gelation / solidification reaction may occur. Careful attention to the product is also required.
When the present inventors use a thermosetting gel electrolyte or the like as an electrolyte, by elaborating the material type or composition of the electrolyte to be used, the gel can be realized without causing the above-mentioned problems. The inventors have found an electrolyte and a solid electrolyte and have completed the present invention.

  The electrochemical display element in the present invention includes not only the electrochromic system but also all display elements that can display by an electrochemical action, such as an electrolytic deposition system and an electrophoretic system.

Hereinafter, as an electrochemical display element of the present invention, ECD will be described as an example.
FIG. 1 schematically shows a schematic cross section of an electrochromic display element which is an example of the present invention. As shown in the figure, an electrode 102 is formed on a substrate 101, and an electrochromic (EC) material layer 103 is formed on the surface of the electrode 102. A separator 104 is provided on the surface of the EC material layer 103.

  On the other hand, the counter substrate 108 provided with the counter electrode 107 is disposed so as to face the substrate 101 through the electrolyte layer 110 so that the electrode surface is on the inner side. The separator 104 is formed with a plurality of minute through holes, and the through holes are filled with an electrolyte. The electrolyte may be either a gel electrolyte or a solid electrolyte.

  In the ECD having this configuration, the EC material causes an electrochemical redox reaction in response to voltage application, and exhibits a phenomenon in which the color of the EC material layer 103 changes. In this case, if the EC material takes a colored state and a colorless state due to the oxidation-reduction reaction, a white separator 104 is provided to display the colored state and the white state in response to voltage application. Can do.

(Electrolytes)
First, the electrolyte used for the electrolyte layer 110, which is a feature of the present invention, will be described.
The electrolyte in the present invention is not particularly limited as long as it is a gel electrolyte or a solid electrolyte cured with a chemical crosslinking agent. Here, the chemical cross-linking agent refers to one that can form a cross-linked structure by forming a chemical bond.

The electrolyte in the present invention is preferably made of the chemical cross-linking agent shown in the following two classifications.
As a first classification, the chemical cross-linking agent is composed of a compound having two or more hydroxyl groups at a terminal and a compound having two or more isocyanate groups (sometimes referred to as “first electrolyte”). In this case, the electrolyte is in the form of a gel or solid containing a crosslinked polymer obtained by reacting a compound having two or more hydroxyl groups at the terminal with a compound having two or more isocyanate groups.

That is, since this electrolyte is a solid or gel-like body containing a specific cross-linked polymer and an electrolyte salt, it does not substantially contain a volatile organic solvent, and is easy to manufacture and safe. It is a novel solid or gel electrolyte that is excellent and has no variation in electrolyte concentration and variation in characteristics. In addition, when the specific cross-linked polymer and the electrolyte are combined, it has a stable composite structure that does not undergo macrophase separation over a long period of time, and has high ionic conductivity even in a solid or gel form. Showing gender.
Therefore, if the above electrolyte is used for ECD, it does not adversely affect the electrochemical characteristics during production, and the device itself has not only excellent impact resistance but also an ECD excellent in responsiveness over a long period of use. Can do.

  The components that are subjected to a crosslinking reaction, such as a compound having two or more hydroxyl groups at a terminal and a compound having two or more isocyanate groups, are each preferably a liquid compound from the viewpoint of manufacturability of an electrochromic device or the like described later. Here, the “liquid compound” refers to a compound that is liquid at room temperature (around 25 ° C.).

  The chemical reaction that forms a crosslinked structure includes polycondensation reaction, polyaddition reaction, radical polymerization reaction, etc., but when it contains an EC active substance that is redox activity, the EC active substance reacts with radical species. In many cases, a radical polymerization reaction system cannot be employed. In addition, in polycondensation reactions, low-molecular-weight by-products such as water and alcohol are generally generated during the condensation, and when used as an electrolyte while the by-products are present, they have a negative effect on the target electrochemical reaction. Sometimes. When the polycondensation reaction proceeds under heating, low molecular weight by-products are distilled off, and the above-mentioned problems can be solved, but for the production of electrochemical display elements such as bubbles are generated during distillation and volume shrinkage occurs. A related problem occurs. In contrast, polyaddition reactions generally have the advantage that they are not inhibited by redox active species and are free from by-products.

  Examples of combinations of reactive groups that perform polyaddition reactions include hydroxyl groups and isocyanate groups; amino groups and isocyanate groups; vinyl groups and hydroxysilyl groups; It is preferable to use a combination of a hydroxyl group and an isocyanate group from the viewpoint of overall stability.

  As a compound having two or more isocyanate groups at the terminal, many compounds have been developed for general-purpose urethane resins, and these can be used. For example, tolylene diisocyanate, hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate and the like, and multimers thereof, or adducts thereof with compounds having a plurality of hydroxyl groups, and the like can be mentioned. Among these, an isocyanuric trimer of an aliphatic diisocyanate is particularly preferable in terms of stability, generally in a liquid state. In order to perform the three-dimensional crosslinking reaction, it is preferable to use a compound having three or more isocyanate groups.

  As the compound having two or more hydroxyl groups at the terminal, those having the hydroxyl group at the terminal of the compound are used. The presence of a hydroxyl group at the end of the compound minimizes the problem of intramolecular and intermolecular association due to hydrogen bonding, and has favorable effects such as low viscosity of the liquid containing it and long pot life. can get.

  Specifically, alkylene glycols (ethylene glycol, propylene glycol, butylene glycol, tetramethylene glycol, etc.) and their multimers; polyhydric alcohols or polyhydric phenols added with alkylene oxide (bis (oligo) Oxyethyl) -modified bisphenol A, (tris (oligooxypropyl) -modified glycerin, etc.); oligoesters, oligocarbonates, oligourethanes having a terminal hydroxyl group.

Among these, in particular, a compound containing a structure represented by the following general formula (1) is generally a liquid, and has a high affinity with an electrolyte or a solvent, and the resulting solid or gel has a high flexibility. Etc. are preferable.
Formula ^{(1): - (CR 1} R 2 -CR 3 R 4 -O) n H

In the general formula (1), R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a hetero atom-containing hydrocarbon group, and n is 2 to 10 Represents an integer.

  Specific examples of the hydrocarbon group having 1 to 10 carbon atoms or the hetero atom-containing hydrocarbon group include a methyl group, an ethyl group, an octyl group, a cyclohexyl group, a phenyl group, a trifluoromethyl group, a methoxyethyl group, and a cyanoethyl group. Is mentioned.

  As the compound having 2 or more hydroxyl groups at the terminal, it is preferable to use a compound having 3 to 6 hydroxyl groups and a compound having 2 hydroxyl groups in combination. A compound having 7 or more hydroxyl groups has high crosslinkability due to hydrogen bonding between molecules, and is generally a highly viscous liquid or solid, and is difficult to handle. In addition, when only a compound having three or more hydroxyl groups is used as the compound having a hydroxyl group, the crosslinking density becomes too high and it becomes difficult to take in an electrolyte and / or a plastic solvent, and the mobility of the electrolyte salt decreases, or Problems such as inability to form a stable gel state may occur. This problem can be improved by using a compound having only two hydroxyl groups and controlling the crosslinking density.

  Furthermore, when performing a three-dimensional crosslinking reaction, it is preferable to use together a compound having only one reactive group capable of polyaddition reaction (for example, a hydroxyl group). Thereby, it becomes possible to control the glass transition temperature of a solid or gel state, and when an electrolyte salt described later is contained, the moving speed can be increased. Moreover, the ionic conductivity can be improved by appropriately selecting the above-mentioned compounds and, in some cases, combining them; improving the affinity between the electrolyte salt, the plastic solvent, etc. and the crosslinked product; improving the flexibility of the crosslinked product Or flame retardancy can be imparted.

  Preferable examples of the compound having only one reactive group capable of polyaddition reaction include oligoalkylene glycol monoalkyl ether, oligoalkylene glycol monocarboxylic acid ester, hydroxypropionitrile, hydroxymethyltetrahydrofuran, ethyl (hydroxyethyl). ) Carbonate, hydroxypropylene carbonate, N- (hydroxypropyl) pyrrolidone, tributyl (hydroxybutyl) ammonium salt, N- (hydroxyethyl) pyridinium salt, 1,2-dimethyl-3- (hydroxypropyl) imidazolium salt, dibutyl ( Hydroxybutyl) phosphate and the like. A preferable addition amount of the compound having only one reactive group is 1 to 30% by mass, and a more preferable addition amount is 5 to 20% by mass with respect to all components that are subjected to the crosslinking reaction.

  The polyaddition reaction generally proceeds even at room temperature, but it is preferable to perform heat treatment and / or addition of a catalyst in order to increase the reaction rate. As heating temperature, 30-200 degreeC is preferable and 50-150 degreeC is more preferable.

  As the catalyst used for the polyaddition reaction, tertiary amines and various metal compounds are known, and tin compounds are particularly preferable, and among them, dialkyltin derivatives such as dibutyltin diacetate are preferable.

  The molar ratio between the compound having two or more hydroxyl groups at the terminal and the compound having two or more isocyanate groups is the ratio of the number of moles of all hydroxyl groups to the number of moles of all isocyanate groups (number of moles of all hydroxyl groups: mole of all isocyanate groups). The number) is preferably in the range of 1:10 to 10: 1, more preferably in the range of 1: 2 to 2: 1.

  In the case of a gel electrolyte or solid electrolyte, if the component that is subjected to the polyaddition reaction is a liquid, the electrolyte salt and, if necessary, a catalyst, leveling agent, antifoaming agent, surfactant, flame retardant, etc. The other components are dissolved and solidified or gelled. A plasticizer may be used for the purpose of improving ion conductivity.

  Specific examples of preferable plasticizers include carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; acetonitrile, propionitrile, malononitrile, methoxypropionitrile, benzonitrile, Nitriles such as; carboxylic acid esters such as butyrolactam, ethylene glycol diacetate, perfluorohexyl acetate; amides such as N-methylcaprolactam, N-methylpyrrolidone, N, N-dimethylacetamide; ethylene glycol dimethyl ether; Ethers such as tetrahydrofuran and methyltetrahydrofuran; ion-containing compounds such as sulfolane and dimethyl sulfoxide; Sufeto, triphenyl phosphate, tributoxyethyl phosphate, tris (bromobutyl) phosphate esters such as phosphate; and the like, they may be used by mixing plural be used alone. These plasticizers are generally volatile liquids and should be kept to a minimum. When using a liquid plasticizer, the boiling point of 150 ° C. or higher, more preferably 200 ° C. or higher is used, so that the problem of volatilization during production and use can be suppressed to a substantially problem-free level. it can.

  In addition, when adding a catalyst for the purpose of accelerating the polyaddition reaction, it can be added simultaneously with the preparation of the solution, but a solution containing only the catalyst and a solution containing the catalyst alone or containing the catalyst are prepared separately. It is preferable from the viewpoint of the pot life of the precursor solution that the mixing is performed immediately before the actual gel solidification. As a method for mixing the two, in addition to a usual method such as a stirring mixing method, a shaking mixing method, an ultrasonic mixing method, etc., a solution containing only the catalyst is used as a coating film, and a solution containing the catalyst alone or the catalyst on its surface A method such as spraying is also effective.

  As the electrolyte salt, for example, an organic room temperature molten salt (organic ionic liquid) is preferable, and as the organic room temperature molten salt, any organic salt that is liquid at room temperature (about 25 ° C.), for example, under the handling environment. The structure may be selected depending on the application. Examples of organic room temperature molten salts include imidazolium salts, pyridinium salts, pyrrolidinium salts {Oono, Industrial Materials, Vol. 48, no. 4, p. 37 (2000); B. McEwen et al. , J .; Electrochem. Soc. , Vol. 146, no. 5, p. 1687 (2000); Bonhotet et al. Iong. Chem. , Vol. 35, p. 1168 (1996)} and the like, and N, N-dialkylated quaternary imidazolium salts are particularly preferable.

  The abundance ratio of the electrolyte salt to the crosslinked polymer (salt: crosslinked polymer) is preferably in the range of 100: 1 to 1:10, more preferably in the range of 50: 1 to 1: 1. Yes, more preferably in the range of 20: 1 to 5: 1.

  In addition, according to the purpose, the electrolyte of the present invention can contain an EC active substance, a redox species on the counter electrode side, a metal ion for electrolytic deposition, and the like.

  Examples of the method for producing the first electrolyte include, for example, components that are subjected to the above-described crosslinking reaction (components that are subjected to polyaddition reaction), electrolyte salts, and EC active substances, metal ions, catalysts, leveling agents, Prepare precursor solution from foaming agent, surfactant, diluting solvent, plasticizing solvent, etc., wet coating such as spin coating method, wire bar coating method, blade coating method, dip coating method, spray coating method, printing method, etc. A method of forming an electrolyte solution layer in a desired place (for example, on an electrode) by a method, and then proceeding with a crosslinking reaction by heat treatment (thermosetting) to form a solid or gel electrolyte layer; A support film having pores such as paper is impregnated with the above precursor solution, and this is pressure-clamped between a pair of electrodes, and then a crosslinking reaction is advanced by heat treatment, so that a solid or gel electrolyte is supported on the support film. To bear A method of injecting the precursor solution into a desired gap (for example, between a pair of electrodes) by capillary action or the like, and then proceeding with a crosslinking reaction by heat treatment to form a solid or gel electrolyte layer And the like.

  The heating temperature is appropriately selected depending on the heat resistant temperature of the EC material, but is preferably 30 ° C. or higher and 200 ° C. or lower, more preferably 50 ° C. or higher and 150 ° C. or lower. The heating time depends on the heating temperature and the like, but may be about 1 minute to 24 hours.

Next, the second classification of the chemical crosslinking agent in the present invention will be described.
As a second classification, the chemical crosslinking agent comprises a compound having two or more nitrogen-containing groups and a compound having two or more electrophilic substituents (sometimes referred to as “second electrolyte”). It is. In this case, the electrolyte is gelled or solidified (gel electrolyte or solid electrolyte) using a reaction product of a compound having two or more nitrogen-containing heterocyclic groups and a compound having two or more electrophilic substituents as a matrix; Become.

That is, in this electrolyte, the nitrogen atom of the compound having a nitrogen-containing group undergoes a nucleophilic substitution reaction with the atom to which the electrophilic substituent of the compound having an electrophilic substituent is bonded, and A strong cross-linked structure is formed by the formation of a new chemical bond with desorption. Along with the reaction, a quaternary nitrogen cation and an anion derived from an electrophilic substituent are formed, but these are generally electrochemically stable and have a high affinity with an electrolyte salt.
Therefore, when the electrolyte is used for ECD, not only the element itself is excellent in durability, but also an ECD excellent in display characteristics and preventing deterioration of characteristics over time can be obtained.

  As the gel electrolyte or solid electrolyte, those obtained by reaction of a compound having two or more nitrogen-containing heterocyclic groups and a compound having two or more electrophilic substituents are preferred. Hereinafter, these compounds and reaction conditions will be described in detail.

  The compound having two or more nitrogen-containing heterocyclic groups in the present invention means a heterocyclic group containing in the ring a nitrogen atom that can be quaternized with an electrophile. As a compound containing a preferable nitrogen-containing heterocyclic group, the following formula (2) may be mentioned.

  However, in the said General formula (2), Z represents a nitrogen-containing heterocyclic group, L represents an organic group, p1 represents the number of the said nitrogen-containing heterocyclic group couple | bonded with the said organic group L, and 2-8. Is an integer.

  The nitrogen-containing heterocyclic ring in the nitrogen-containing heterocyclic group represented by Z may be an unsaturated ring or a saturated ring, and may have an atom other than a nitrogen atom. Examples of the unsaturated heterocyclic ring include a pyridine ring, an imidazole ring, a thiazole ring, an oxazole ring, and a triazole ring. Examples of saturated heterocycles include morpholine ring, piperidine ring, piperazine ring and the like. Preferred nitrogen-containing heterocycles are unsaturated heterocycles, more preferably pyridine rings or imidazole rings. These are preferably unsubstituted, but may be substituted with an alkyl group such as a methyl group.

  The organic group L is not particularly limited as long as it has a site to which 2 to 8 nitrogen-containing heterocyclic groups Z can be bonded. In the following, it will be called 2-8 valence according to the number of the sites. In each case where the organic group L is divalent to octavalent, preferred structures are as follows.

When L is a divalent organic group, any divalent organic group having at least one atom selected from the group consisting of C, O, N and S may be used, but an alkylene group, an arylene group, -CR ⁵ = CR ^6- , -CR ⁵ = N-, -N = N-, -N (O) = N-, -CO-, -O-, -S-, -NR ⁷ -,-(C≡C) ₁ to ₃ —, or an organic group composed of a combination of these organic groups (units) (for example, —COO—, —COS—, —CONR ⁷ —, —COCH ₂ —, —OCH ₂ —, —OCH ₂ CH ₂ —, —O (CH ₂ ) ₃ to ₁₂ —, —CH ₂ NR ⁷ —, —CR ⁵ ═CR ⁶ —CO—, —OCOO—, etc.) or those having a plurality of these organic group units are preferred. . Of these, an organic group containing an alkylene group, an arylene group, —CO—, or an oxyalkylene group (consisting of an alkylene group and —O—) is more preferable. Particularly preferred is an organic group containing —OCH ₂ CH ₂ —.
In the above, R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group.

When L is a trivalent organic group, a trivalent organic group represented by the following basic structure (where R ₁₀ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms), or any of them: The trivalent organic group comprised by the combination with the said bivalent organic group is preferable.

  When L is an organic group having 5 to 8 valences, an organic group having a configuration in which the above trivalent organic group and / or a tetravalent organic group are combined or a divalent organic group is added thereto is used. Can do.

  The number p1 of the nitrogen-containing heterocyclic group Z bonded to the organic group L may be anything as long as it is an integer of 2 or more, but generally 2 to 8 is preferable, and 2, 3 or 4 is more preferable. If p1 is less than 2, the reaction product with the compound having an electrophilic substituent does not become a polymer, and if it exceeds 8, the mobility of the electrolyte salt may decrease, which may be undesirable.

The organic group L may have a substituent, and examples of preferred substituents include the following.
(A) Substituted or unsubstituted alkyl group (which may be linear or branched): those having 1 to 24 carbon atoms are preferred. Examples of the substituent that can be bonded to the alkyl group include a halogen atom, a cyano group, and alkoxy. Group, alkoxycarbonyl group, aryl group, heterocyclic group and the like are preferable. Preferable specific examples of such a substituted or unsubstituted alkyl group include, for example, methyl group, ethyl group, i-propyl group, butyl group, t-butyl group, octyl group, 2-ethylhexyl group, trifluoromethyl group, Cyanomethyl group, benzyl group, 3- (1-octylpyridinium-4-yl) propyl group, 3- (1-butyl-3-methylpyridinium-4-yl) propyl group, 2-methoxyethyl group, propoxyethyl group, An ethoxycarbonylmethyl group etc. are mentioned.

(B) Substituted or unsubstituted alkenyl group (which may be linear or branched): those having 2 to 24 carbon atoms are preferred, and examples thereof include a vinyl group and an allyl group.
(C) An aryl group which may be substituted or condensed: those having 6 to 24 carbon atoms are preferred, and the substituent which can be bonded to the aryl group is preferably a halogen atom, a cyano group, an alkyl group or the like. . Specific examples of such a substituted or unsubstituted aryl group include a phenyl group, a 4-methylphenyl group, a 3-cyanophenyl group, a 2-chlorophenyl group, and a 2-naphthyl group.

(D) a nitrogen-containing heterocyclic group which may be substituted or condensed (in the case of a heterocyclic group, the nitrogen in the ring may be quaternized): preferably has 2 to 24 carbon atoms The substituent that can be bonded to the heterocyclic group is preferably a halogen atom, a cyano group, an alkyl group, or the like. Preferable specific examples of such a substituted or unsubstituted heterocyclic group include, for example, 4-pyridyl group, 2-pyridyl group, 1-octylpyridinium-4-yl group, 2-pyrimidyl group, 2-imidazolyl group, 2 -Thiazolyl group and the like.

(E) Substituted or unsubstituted alkoxy group: Preferably it has 1 to 24 carbon atoms, and the substituent that can be bonded to the alkoxy group is preferably a halogen atom, a cyano group, an alkyl group or the like. Preferable specific examples of such a substituted or unsubstituted alkoxy group include, for example, methoxy group, ethoxy group, butoxy group, octyloxy group and the like.

(F) Acyloxy group: Preferably it is C1-C24, for example, an acetyloxy group, a benzoyloxy group, etc. are mentioned.
(G) Substituted or unsubstituted alkoxycarbonyl group: Preferably, it has 2 to 24 carbon atoms, and the substituent that can be bonded to the alkoxycarbonyl group is preferably a halogen atom, a cyano group, an alkyl group or the like. Preferable specific examples of such a substituted or unsubstituted alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.
(H) Others include cyano group, halogen (for example, chlorine, bromine) and the like.

  Preferred specific examples of the compound having a nitrogen-containing heterocyclic group falling within the category of the general formula (2) are exemplified in (1-1) to (1-17), but the present invention is not limited to these. Absent.

  As the compound having two or more nitrogen-containing heterocyclic groups, polyvinyl pyridine, a copolymer of vinyl pyridine and any other vinyl monomer, or the like can also be used.

  The compound having two or more electrophilic substituents in the present invention is a bifunctional or higher functional alkylating agent capable of quaternizing a nitrogen-containing group, and the electrophilic substituent is removed during the alkylation reaction. If it is a substituent which can become a leaving group, there will be no limitation in particular. A compound having a preferable electrophilic substituent includes a compound represented by the following formula (3).

  In general formula (3), Y represents an electrophilic substituent, L ′ represents an organic group, p2 represents the number of the electrophilic substituent bonded to the organic group L ′, and 2 to 8 Is an integer.

  Examples of Y include a halogen atom (chlorine, bromine, iodine), a substituted or unsubstituted acyloxy group (the substituent is preferably a halogen atom, an alkyl group, etc., and specific examples include an acetoxy group, a trifluoroacetyloxy group, A trichloroacetyloxy group, etc.), a sulfonyloxy group (a methylsulfonyloxy group, a tolylsulfonyloxy group, a trifluoromethylsulfonyloxy group, etc.) can be mentioned, and chlorine is particularly preferred. Bromine and iodine have relatively high electrochemical activity, and depending on the type of EC active substance used, the EC reaction may be inhibited.

  L ′ and p2 in the general formula (3) are the same as those described for L and p1 in the general formula (2), respectively.

  Preferred specific examples of the compound having two or more electrophilic substituents are shown in (2-1) to (2-22), but the present invention is not limited to these.

  When the compound represented by the general formula (2) and the compound represented by the general formula (3) are combined, at least one of p1 and p2 is preferably 3 or more. If both p1 and p2 are less than 3, it is not preferable because gelation or solidification is difficult.

  The gelation or solidification reaction is preferably carried out in the presence of an electrolyte salt in addition to the compound having two or more nitrogen-containing heterocyclic groups and the compound having two or more electrophilic substituents. In the gel electrolyte or solid electrolyte in the present invention, an electrolyte salt is essential as an electrolyte. A salt can be added after gelation or solidification, but in this case, it is difficult to uniformly disperse the electrolyte salt in the gel, which is not preferable.

  As the electrolyte salt, the same salt as that used for the first electrolyte can be used.

  As a method for producing the second electrolyte, first, a compound having two or more nitrogen-containing heterocyclic groups, a compound having two or more electrophilic substituents, and an electrolyte salt are dissolved in a common solvent (plasticizer). To make an electrolyte solution. Moreover, when using the above-mentioned organic room temperature molten salt, it is not necessary to use a solvent.

  As a solvent (plasticizer), the thing similar to what was used for the 1st electrolyte can be used.

  The concentration of the compound having a nitrogen-containing heterocyclic group in the electrolyte solution is preferably in the range of 0.1 to 1 mol / L, more preferably in the range of 0.2 to 0.6 mol / L. If the compound having a nitrogen-containing heterocyclic group is less than 0.1 mol / L, the crosslinking strength is insufficient, and if it exceeds 1 mol / L, the mobility of the electrolyte salt may decrease, which may be undesirable. In addition, the compound which has a nitrogen-containing heterocyclic group may be used independently, or may use 2 or more types together.

  The amount of the compound having an electrophilic substituent in the electrolyte solution is such that the molar ratio of the electrophilic substituent to the reactive nitrogen atom in the compound having a nitrogen-containing heterocyclic ring is in the range of 0.01 to 2. It is preferable to set, and it is more preferable to set it in the range of 0.05 to 1.5. A compound having an electrophilic substituent may be used alone or in combination of two or more.

Other adjustments in the formulation of the electrolyte solution, the application method, and the like are the same as those described in the first electrolyte.
The heating temperature is appropriately selected depending on the heat resistant temperature of the EC material, but is preferably 30 ° C. or higher and 200 ° C. or lower, more preferably 50 ° C. or higher and 150 ° C. or lower. The heating time depends on the heating temperature and the like, but may be about 1 minute to 24 hours.

Next, another configuration of the ECD (electrochemical display element) will be further described with reference to FIG.
As the substrates 101 and 108, as long as at least the display side is transparent and can be used as a base material on which an electrode is provided, the material, shape, structure, size, and the like are not particularly limited and can be appropriately designed. Specifically, a glass plate, a polymer film, etc. are mentioned suitably, for example. Polymer film materials include tetraacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate ( PAr), polysulfone (PSF), polyethersulfone (PES), polyetherimide (PEI), cyclic polyolefin and the like.

  The electrodes 102 and 107 are not particularly limited as long as they are transparent at least on the display side and can conduct electricity, and can be appropriately selected according to the purpose. For example, indium tin oxide (ITO), tin oxide zinc (IZO) ), Tin oxide doped with antimony (ATO), tin oxide doped with fluorine (FTO), indium oxide, zinc oxide, platinum, gold, silver, rhodium, copper, chromium, carbon and the like. Among these, tin-doped oxide (FTO) and indium tin oxide (ITO) doped with fluorine from the viewpoints of low surface resistance, good heat resistance, chemical stability, high light transmittance, and the like. preferable.

  The material used for the EC material layer 103 (electrochromic active substance (EC active substance)) is not particularly limited as long as it exhibits an action of color development or decoloration by at least one of an electrochemical oxidation reaction and a reduction reaction. The organic compound, metal complex, etc. are mentioned suitably, for example. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the metal complex include Prussian blue, metal-bipyridyl complex, metal phenanthroline complex, metal-phthalocyanine complex, metaferricyanide, and derivatives thereof.

  Examples of the organic compound include (1) pyridine compounds, (2) conductive polymers, (3) styryl compounds, and (4) other organic dyes.

  Examples of the (1) pyridine compounds include methylenebispyridinium, phenanthroline, viologen, and derivatives thereof.

  Examples of the conductive polymer (2) include polypyrrole, polythiophene, polyaniline, polyphenylenediamine, polyaminophenol, polyvinylcarbazole, and derivatives thereof.

  Examples of the (3) styryl compounds include 2- [2- [4- (dimethylamino) phenyl] ethenyl] -3,3-dimethylindolino [2,1-b] oxazolidine, 2- [4- [4- (Dimethylamino) phenyl] -1,3-butadienyl] -3,3-dimethylindolino [2,1-b] oxazolidine, 2- [2- [4- (dimethylamino) phenyl] ethenyl]- 3,3-dimethyl-5-methylsulfonylindolino [2,1-b] oxazolidine, 2- [4- [4- (dimethylamino) phenyl] -1,3-butadienyl] -3,3-dimethyl-5 -Sulfonylindolino [2,1-b] oxazolidine, 3,3-dimethyl-2- [2- (9-ethyl-3-carbazolyl) ethenyl] indolino [2,1-b] oxazolidine 2- [2- [4- (acetylamino) phenyl] ethenyl] -3,3-dimethyl-indolino [2,1-b] oxazolidine, and the like.

  Examples of (4) other organic dyes include carbazole, methoxybiphenyl, anthraquinone, quinone, diphenylamine, aminophenol, Tris-aminophenylamine, phenylacetylene, cyclopentyl compound, benzodithiolium compound, squalium salt, cyanine, merocyanine Phenanthroline, pyrazoline, redox indicator, pH indicator, derivatives thereof, and the like.

In addition, the EC active substance is a reduction coloring type that shows colorless or ultra-light color in the oxidation state and develops color in the reduction state, and an oxidation coloring type that shows colorless or ultra-light color in the reduction state and develops color in the oxidation state Any of the multicolor coloring types that exhibit color development in the reduced state or in the oxidized state and develop several kinds of colors depending on the degree of reduction or oxidation may be appropriately selected according to the purpose.
Of the EC active substances, a viologen derivative is preferably used from the viewpoint of repeated stability.

  There is no restriction | limiting in particular as a combination in the case of using together 2 or more types of said EC active substance, According to the objective, it can select suitably.

  In the present invention, it is preferable that the EC material layer 103 has a porous structure with a roughness coefficient in the range of 10 to 2000, and an electrochromic active substance is provided on the surface thereof. As a result, the electrode area can be substantially increased, and the color development efficiency in ECD can be improved.

In the present invention, the “roughness coefficient” is defined as the ratio of the actual surface area to the projected area (actual surface area / projected area), and the actual surface area is the total surface area of the porous structure, and the projected area is the effective electrode portion. It is a physical property value generally used as an index of a porous electrode.
If the roughness coefficient is less than 10, a sufficient electrode area expansion effect may not be obtained. If the roughness coefficient exceeds 2000, voids in the porous structure may become too small, and movement of the electrolyte salt may be inhibited.

  In the present invention, the porous layer is formed of a semiconductor material, and the EC active substance is chemically adsorbed on the surface thereof in a monomolecular layer state, so that the EC is fully exposed in the fine pores on the surface of the porous layer. It is preferable to support the active substance to form the EC material layer 103 because the response speed and the repeated durability can be improved as the electrode area is increased.

The porous layer can be obtained, for example, by forming semiconductor fine particles in a layer form on the electrode surface.
The material of the semiconductor fine particles is preferably a metal oxide, and specifically includes titanium oxide, vanadium oxide, tungsten oxide, indium oxide, iridium oxide, nickel oxide, zinc oxide, tantalum oxide, and the like. Among these, titanium oxide and zinc oxide are preferable in terms of electrochemical stability.

  The shape of the fine particles is not particularly limited and may be appropriately selected depending on the purpose. The shape may be any of spherical, tube, rod, and whisker shapes, and two or more types of fine particles having different shapes may be used. It can also be mixed. In the case of the spherical particles, the average particle size is preferably 1 to 1000 nm, more preferably 5 to 100 nm. Two or more kinds of fine particles having different particle size distributions may be mixed.

  The method for forming the porous layer is not particularly limited and can be appropriately selected according to the type of fine particles. For example, the metal anodizing method, electrolytic deposition method, electrophoretic electrodeposition method, fine particle dispersion Screen printing method, sol-gel method, thermal oxidation method, vacuum vapor deposition method, dc and rf sputtering method, chemical vapor deposition method, molecular beam deposition method, laser ablation method, etc. are mentioned. You can also.

The average diameter of the micropores in the porous layer is preferably in the range of 1 to 1000 nm. The pore size particle size distribution of the micropores can be determined by a known method, and for example, it is preferable to measure by a gas adsorption method obtained from an adsorption isotherm such as nitrogen or krypton, or an X-ray small angle scattering method.
The thickness of the porous layer is preferably in the range of 1 to 100 μm.

  The method for supporting the EC active substance on the surface of the porous layer is not particularly limited, and a known technique can be used. For example, a dry process such as a vacuum deposition method, a coating method such as spin coating, an electric field deposition method, an electric field polymerization method, and a natural adsorption method in which the material to be supported is immersed in a solution can be appropriately selected. In particular, the natural adsorption method does not require a special device that can support the EC active material evenly, for example, even in the fine pores of the metal oxide layer. In many cases, it is about a monomolecular layer. It is a preferable method because it has many advantages such as no extra amount. Specifically, in this natural adsorption method, after forming a metal oxide layer (porous layer) having micropores on a substrate, the substrate is immersed in a solution containing an EC active substance, and the EC active substance Is penetrated into the metal oxide layer, and the EC active substance is supported on the surface of the fine pores of the metal oxide layer. In particular, it is preferable to use a compound having a functional group such as a phosphoric acid group, a carboxylic acid group, a boric acid group, and a hydroxyl group that can be chemically adsorbed on the surface of the metal oxide as the EC active substance.

  In the present invention, the separator 104 provided as necessary is usually provided between the counter electrode 107 and the electrochromic material layer 103, and has a structure in which a large number of insulating and fine through-holes are formed. The electrolyte can be impregnated and permeated through the through hole.

  In the ECD having the configuration shown in FIG. 1, the through hole of the separator 104 is filled with an electrolyte. Therefore, in the manufacture of ECD, an insulating separator layer having a plurality of micropores is formed on the surface of the EC material layer 103, and then the electrolyte solution before thermosetting is applied or sealed on the separator layer to form the finer layer. After filling the pores with the electrolyte, the electrolyte is thermally cured.

As the separator 104, an insulating resin is preferably used. For example, a sheet of polyethylene terephthalate (PET), polypropylene, polyethylene, polyimide, or the like can be used. As described above, the separator 104 in the present invention is preferably white as a white background in the display element. In this case, a white pigment or the like may be dispersed in the material.
The thickness of the separator 104 is preferably in the range of 1 to 100 μm.

  The electrochemical display element of the present invention has been described above by taking the electrochromic display element as an example. In the electrochemical display element of the present invention, since gel electrolyte or solid electrolyte thermally cured with a chemical crosslinking agent is used as an electrolyte, there is no concern about decomposition of display dyes such as UV chemical crosslinking type electrolytes, and physical crosslinking. There is no need for heating when impregnating the porous electrode layer such as a type of electrolyte (gel solid at normal temperature and liquid at high temperature), and it is extremely excellent in manufacturability.

  Furthermore, chemical cross-linking by thermosetting is tough, and when the electrochemical display element of the present invention is used as a flexible display element, it is resistant to pushing and bending, and leakage of electrolyte solution at the time of breakage, etc. In addition, the volatilization rate of the solvent is remarkably suppressed. In addition, in the crosslinking reaction at the time of heat curing, since there is no desorbing component that adversely affects electrochemically such as water, the display characteristics do not change not only during production but also during long-term use.

  The electrochemical display element of the present invention can be suitably used in various fields. For example, a large commercial display device such as a stock price or a timetable display plate; a light control element such as an antiglare mirror or a light control glass; It can be suitably used for mobile display devices such as electronic paper, electronic albums, electronic books, and electronic medical records; monitor display elements for personal computers, copiers, and the like.

Hereinafter, the present invention will be described specifically by way of examples.
<Example 1>
(Production of element)
-Formation of porous layer and EC material layer-
Prepare a 20 mm x 30 mm PET film (substrate) with an ITO transparent conductive layer (electrode) on the surface by sputtering, and apply spacer spacers to both ends of the ITO transparent conductive layer (5 mm wide from the end). Tape was affixed. Next, a titanium oxide nano paste (manufactured by Solaronix, titanium oxide average particle size: 13 nm) was applied onto the ITO transparent conductive layer using a glass rod. The pressure-sensitive adhesive tape was peeled off and air-dried at room temperature for 2 hours, and then heat-treated on a hot plate at 150 ° C. for 10 minutes to form a porous layer having a thickness of 10 μm on the electrode (roughness coefficient: about 1000).

  Next, an ethanol solution of a chloride salt of a viologen derivative having a phosphoric acid group having the following structure, which is a dye having both chemisorption and electrochromic activity on the titanium oxide surface, is formed on the substrate on which the porous layer is formed ( (Concentration: 10 mmol / L) for 3 hours. This was taken out, washed with ethanol, and then naturally dried to form an EC material layer as an adsorption layer on the porous layer surface. In the following structural formula, Hex represents a hexyl group.

-Fabrication of electrochromic display elements-
As an electrolyte solution, γ-butyrolactone (boiling point: 204 ° C.) as a solvent, ferrocene as a redox species at the counter electrode, chloride salt of 1-methyl-3-hexylimidazolium as an electrolyte salt, two or more as a chemical crosslinking agent A solution was prepared by dissolving polyvinylpyridine having a nitrogen-containing group (weight average molecular weight: 2000) and 1,2,4,5-tetra (chloromethyl) benzene having two or more electrophilic substituents. (Electrolyte solution A). The content of each component is such that the molar ratio of the nitrogen-containing group to the electrophilic substituent is 1: 1, the mass ratio of all the crosslinking agent components to the solvent is 1: 4, and ferrocene is 1% by mass of the solvent amount. It adjusted so that it might become.

  Next, a white polypropylene porous separator (manufactured by Ube Industries, thickness: 100 μm) is stacked on the porous layer provided with the EC material layer, and the electrolyte solution A is sufficiently suspended on the surface of the separator. The micropores were filled with electrolyte. On the other hand, a platinum thin film is sputtered on the ITO side of the PET film provided with the same ITO transparent conductive layer as described above, and the platinum side is overlapped with the electrolyte, and both PET films are pressed and fixed at 150 ° C. at 30 ° C. Heat treatment was performed for a minute, and the electrolyte solution was gelled to obtain an electrochromic display element (ECD1).

(Element evaluation)
-EC display characteristics, storage stability-
When a rectangular wave voltage of ± 1.5 V was applied to the ITO electrode of the obtained element (1 sec cycle), it was blue when the electrode on the side where the porous layer was provided became negative, and transparent when the electrode became positive (the separator The electrochromic behavior associated with the reduction and oxidation of the viologen derivative that turns white) is confirmed, and it was verified that this device can effectively function as an electrochromic display device. Incidentally, it is presumed that the ferrocene redox reaction occurs at the counter electrode in response to the reduction oxidation reaction of the viologen derivative at the electrode on the side where the porous layer is provided.

  When the ECD1 was left in a room temperature atmosphere for one week without performing a sealing process separately, and then subjected to the same test as described above, it showed an electrochromic behavior equivalent to that in the initial stage and had excellent stability. confirmed.

-Heat resistance and scratch resistance-
When ECD1 was left in an environment of 80 ° C. for 5 hours and then subjected to the same test as described above, it was confirmed that it showed an electrochromic behavior equivalent to that in the initial stage and was excellent in heat resistance.
Moreover, although the display part of ECD1 was pressed with a hard metal and scratched, liquid leakage or the like did not occur.

<Example 2>
(Production of element)
As an electrolyte solution, N-methylpyrrolidone (boiling point: 202 ° C.) is used as a solvent, ferrocene as a redox species on the anode side, chloride salt of 1-methyl-3-hexylimidazolium as electrolyte salt, three isocyanate groups Isocyanuric ring trimer of hexamethylene diisocyanate, which is a liquid compound (D-170HN, manufactured by Takeda Pharmaceutical Company Limited), tris (oligooxypropyl) glycerin (manufactured by Sanyo Chemical Co., Ltd.), which is a liquid compound having three terminal hydroxyl groups Sanix GP-1000) and a solution in which dibutyltin diacetate as a polyaddition reaction catalyst was dissolved were prepared (electrolyte solution B). The content of each component is such that the molar ratio of isocyanate group to hydroxyl group is 1: 2, the mass ratio of all crosslinker components to the solvent is 1: 4, ferrocene is 1% by mass of the solvent amount, and the polyaddition reaction catalyst is It adjusted so that it might become 0.1 mass% of the total amount of crosslinking agent components.

  Next, ECD2 was produced in the same manner as in Example 1 except that the electrolyte solution B was used instead of the electrolyte solution A as the electrolyte solution.

(Element evaluation)
With respect to ECD2, the display characteristics, storage stability, heat resistance characteristics and scratch resistance characteristics were examined in the same manner as in Example 1. As a result, it was confirmed that it had excellent characteristics in all points as in Example 1.

<Comparative Example 1>
In the electrolyte solution A used for manufacturing the device of Example 1, a mixed solution from which the chemical cross-linking agent (polyvinylpyridine and 1,2,4,5-tetra (chloromethyl) benzene) was removed was used, and this mixed solution was used as the electrolyte solution. ECD3 was produced in the same manner as in Example 1 except that it was used as.

Evaluation similar to Example 1 was performed about obtained ECD3.
As a result, the same results were obtained for the initial notation characteristics, but in the evaluation after standing for one week and after standing at 80 ° C., the electrolyte was volatilized or flowed out, and the color development and decoloring properties were remarkably lowered. Further, when the ECD was broken after the evaluation was completed, the electrolyte solution leaked.

<Comparative Example 2>
In Example 1, instead of the heat treatment for thermally cross-linking and curing the chemical cross-linking agent, a UV irradiation treatment generally used for UV cross-linking and curing of a UV-curing type chemical cross-linking agent (UV manufactured by Ushio Electric Co., Ltd.) ECD4 was produced in the same manner as in Example 1 except that the irradiation apparatus was performed.

  Evaluation similar to Example 1 was performed about obtained ECD4. As a result, compared to Example 1, the blue color density was significantly lower. This is presumably because the viologen derivative was directly photodegraded by UV irradiation treatment, or the viologen derivative was oxidatively decomposed by the photocatalytic action of titanium oxide.

  As can be seen from the above results, the electrochemical display element (ECD) of the present invention of the example has excellent heat resistance and scratch resistance in addition to stable display characteristics. On the other hand, in the ECD using the conventional type electrolyte, a problem has occurred in either display characteristics or stability.

It is a schematic structure sectional view showing an example of the electrochemical display element of the present invention.

Explanation of symbols

101, 108 Substrate 102, 107 Electrode 103 EC material layer 104 Separator 110 Electroplasma layer

Claims (10)

  An electrochemical display element comprising a pair of electrodes, including at least an electrolyte between the pair of electrodes, wherein the electrolyte is a gel electrolyte or a solid electrolyte thermally cured by a chemical crosslinking agent.   The electrochemical display element according to claim 1, wherein the chemical crosslinking agent comprises a compound having two or more hydroxyl groups at a terminal and a compound having two or more isocyanate groups. The electrochemical display element according to claim 2, wherein the compound having two or more hydroxyl groups at the terminal is an oligoalkylene glycol derivative having a structure represented by the following general formula (1).
Formula ^{(1): - (CR 1} R 2 -CR 3 R 4 -O) n H
(In the general formula (1), R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a hetero atom-containing hydrocarbon group, and n is an integer of 2 to 10) Represents.)   2. The electrochemical display element according to claim 1, wherein the chemical crosslinking agent comprises a compound having two or more nitrogen-containing groups and a compound having two or more electrophilic substituents. The electrochemical display element according to claim 4, wherein the compound having two or more nitrogen-containing groups is represented by the following general formula (2).

(In the general formula (2), Z represents a nitrogen-containing heterocyclic group, L represents an organic group, p1 represents the number of the nitrogen-containing heterocyclic group bonded to the organic group L, and is an integer of 2 to 8 .) The electrochemical display element according to claim 4, wherein the compound having two or more electrophilic substituents is represented by the following general formula (3).

(In General Formula (3), Y represents an electrophilic substituent, L ′ represents an organic group, p2 represents the number of the electrophilic substituents bonded to the organic group L ′, and 2-8. Is an integer.)   The electrochemical display element according to claim 4, wherein the electrophilic substituent is at least one selected from a halogen atom, an acyloxy group, and a sulfonyloxy group.   2. The electrochemical display element according to claim 1, wherein a porous layer having a roughness coefficient in the range of 10 to 2000 is provided on at least one surface of the pair of electrodes.   The electrochemical display element according to claim 8, wherein an electrochromic active material is provided on a surface of the porous layer.   The electrochemical display element according to claim 1, wherein a white separator capable of impregnating and transmitting an electrolyte is provided between the pair of electrodes.

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