JP2012248408A - Barrier membrane for redox flow battery and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a barrier membrane for a redox flow battery preservable in a dried state and having excellent battery performance, chemical resistance, and durability, and a manufacturing method thereof.SOLUTION: A barrier membrane for a redox flow battery is made by forming an ion exchange membrane, in which an inorganic porous granular material to which an ion exchange resin is deposited is dispersed in a matrix, on cavities and/or a surface of a sheet base material having a large number of the cavities communicating with the front and rear of a sheet. A manufacturing method of the barrier membrane includes the following steps of: depositing the ion exchange resin to the inorganic porous granular material; adjusting a mixed liquid containing the inorganic porous granular material to which the ion exchange resin is deposited, the matrix, and a dispersant; filling the sheet base material having a large number of the cavities communicating with the front and rear of the sheet with the inorganic porous granular material to which the ion exchange resin is deposited; impregnating the sheet base material filled with the inorganic porous granular material with the mixed liquid; and heating and drying the sheet base material impregnated with the mixed liquid, and forming the ion exchange membrane on the sheet base material.

Description

  The present invention relates to a redox flow battery membrane that can be stored in a dry state, is easy to handle, and has excellent battery performance and durability, and a method for producing the same.

Conventionally, the diaphragm used in the redox flow battery is a membrane that separates the catholyte and the anolyte in the cell container. The catholyte and the anolyte are in contact with each other through the diaphragm, and protons (hydrogen ions H ⁺ ) Moves through the diaphragm, but an ion exchange membrane having a property that the metal ions of the catholyte and anolyte do not permeate is used.

  As a general ion exchange membrane, for example, a porous base material membrane having pores communicating with the membrane surface direction and the front and back of the membrane by a melting method or a wet method, and electrolyte impregnation in which pores at all peripheral edges are closed The membrane is disclosed in Patent Document 1, and an example of perforation by corona discharge as a porous membrane containing an aromatic polyamide, a method of producing a porous membrane by a wet film-forming method, and the obtained porous membrane are used. Patent Document 2 discloses a discharge capacity of a battery, and a cross-linked polymer having an anion exchange group on a polytetrafluoroethylene porous membrane or a nonwoven fabric having a porous structure formed by a stretching method or a pore-forming method. Patent Document 3 discloses an invention relating to a composite battery diaphragm. However, in the above examples, the ion exchange resin is attached to a porous film or the like perforated by a melting method, a wet method, a corona discharge, a stretching method, etc. No membrane has been found for forming an ion exchange membrane on a sheet base material in which an ion exchange resin is adhered and the inorganic porous powder particles to which the ion exchange resin is adhered are dispersed in a matrix such as lacquer.

  There are two types of conventional battery diaphragms, a wet storage type and a dry storage type. For example, a dry storage type such as a perfluorocarbon sulfonic acid polymer membrane represented by Nafion (registered trademark). Other than the above, since the film deteriorates drastically when it is dried, for example, it is often required to be sealed in a bag filled with 3% saline solution and stored in a cool and dark place. Each of the above examples is a porous film as a base material, and an ion exchange resin is adhered to the porous film base material, and the bonding between the porous film as the base material and the ion exchange resin is performed. Because it is relatively weak, it may deteriorate due to repeated use or contact with air, resulting in a change in performance, or a shape change due to membrane swelling and shrinkage. However, there is a problem in handling that the membrane is attached in a facility such as a working pool and must be placed in a moist environment even after the attachment.

Japanese Patent Laid-Open No. 11-86909 JP 2008-106261 A JP 2000-235849 A

  Many of the battery membranes currently in wide use are ion exchange membranes in which an ion exchange resin is attached to a porous film having pores in a plastic film or an engineering plastic film as described above. The pores have a pore size diameter of 10 to 10,000 nm and a small carrying capacity for attaching the ion exchange resin. Therefore, there is a problem that the proton permeability is inferior, the charge / discharge efficiency is low, and the leakage of the polar liquid is liable to occur. Accordingly, the inventors of the present application have made extensive studies on battery diaphragms, and the pore size diameter is smaller and the variation is narrower than the porous film, for example, inorganic porous materials such as diatomaceous earth having a pore size diameter of 2 to 50 nm. By attaching an ion exchange resin to the powder and dispersing the inorganic porous powder with the ion exchange resin in a matrix such as lacquer, it is difficult for the ion exchange resin to be released even after repeated charge and discharge. In addition, the inventors have obtained the knowledge that the proton permeation amount is increased and the stable liquid can be obtained by preventing the leakage of the polar liquid, and the main object of the present invention is to improve the proton permeability. An excellent redox flow battery membrane having excellent battery performance, chemical resistance and durability, and excellent battery performance, chemical resistance and durability since it is excellent in preventing leakage of polar liquid and can be stored dry. And to provide a production method.

  In order to solve the above-described problems, the present invention provides an inorganic porous powder in which an ion exchange resin is adhered to the voids and / or the surface of a sheet substrate having a large number of voids communicating with the front and back of the sheet. A redox flow cell membrane characterized in that an ion exchange membrane in which particles are dispersed in a matrix is formed (claim 1).

  In order to solve the above-mentioned problems, the present invention provides a redox flow battery diaphragm comprising an ion exchange membrane in which an inorganic porous granular material to which an ion exchange resin is adhered is dispersed in a matrix. ).

  In order to solve the above-mentioned problems, the present invention preferably uses the redox flow battery diaphragm, wherein the ion-exchange resin is a polysulfone ion-exchange resin. ).

（式中、ｍは繰り返し単位を表す０または１以上の整数、ｎは１以上の整数とする。）
（式中、Ｘはイオン交換基を有するフェノール・その塩またはイオン交換基を有する４，４’−ジヒドロキシジフェニルスルホン・その塩、Ｒはアルキル基とする。）
で表される架橋が導入された重合体からなることを特徴とする前記のレドックスフロー電池用隔膜とすることが好ましい（請求項４）。 In order to solve the above-mentioned problem, the present invention provides:
The ion exchange resin is

(In the formula, m is 0 or an integer of 1 or more representing a repeating unit, and n is an integer of 1 or more.)
(In the formula, X is a phenol / ion salt having an ion exchange group or 4,4′-dihydroxydiphenyl sulfone / a salt having an ion exchange group, and R is an alkyl group.)
It is preferable to use the redox flow battery diaphragm characterized in that it is made of a polymer introduced with a crosslink represented by the formula (Claim 4).

  In order to solve the above-mentioned problems, the present invention provides a resin comprising the matrix, lacquer, other synthetic resins having a hydroxyl group or a naturally-derived resin, and a combination of these resins and an ion exchange resin. Preferably, the redox flow battery diaphragm is made of at least one of them.

  Further, in order to solve the above-mentioned problems, the present invention provides the inorganic porous granular material comprising diatomaceous earth, sepiolite, zeolite, perlite, calcium silicate, kaolin, attapulgite, vermiculite, cristobalite, and other silica porous bodies. Preferably, the redox flow battery diaphragm is characterized by comprising at least one of the above (Claim 6).

  In order to solve the above problems, the present invention includes a step of attaching an ion exchange resin to an inorganic porous powder granule, an inorganic porous powder particle to which the ion exchange resin is adhered, a matrix, and a dispersion medium. A step of preparing a mixed liquid containing, a step of filling an inorganic porous powder granule in which the ion exchange resin is attached to a sheet base material having a large number of voids communicating with the front and back of the sheet, and the inorganic porous powder Impregnating the sheet base material filled with the granular material with the mixed liquid; and heating and drying the sheet base material impregnated with the mixed liquid to form an ion exchange membrane on the sheet base material. A method for producing a featured redox flow battery diaphragm is provided.

  In order to solve the above problems, the present invention includes a step of attaching an ion exchange resin to an inorganic porous powder granule, an inorganic porous powder particle to which the ion exchange resin is adhered, a matrix, and a dispersion medium. And a method for producing a redox flow battery membrane, comprising: a step of preparing a mixed solution comprising: a step of forming an ion exchange membrane by heating and drying after planarizing the mixed solution; (Claim 8).

  In order to solve the above problems, the present invention is preferably a method for producing a redox flow battery membrane according to the present invention, wherein the ion exchange resin is a polysulfone ion exchange resin ( Claim 9).

（式中、ｍは繰り返し単位を表す０または１以上の整数、ｎは１以上の整数とする。）
（式中、Ｘはイオン交換基を有するフェノール・その塩またはイオン交換基を有する４，４’−ジヒドロキシジフェニルスルホン・その塩、Ｒはアルキル基とする。）
で表される芳香族ポリスルホン系重合体であって架橋導入性能を有する重合体およびそのプレポリマーからなることを特徴とする請求項７〜９記載のレドックスフロー電池用隔膜の製造方法とすることが好ましい（請求項１０）。 In order to solve the above-mentioned problem, the present invention provides:
The ion exchange resin is

(In the formula, m is 0 or an integer of 1 or more representing a repeating unit, and n is an integer of 1 or more.)
(In the formula, X is a phenol / ion salt having an ion exchange group or 4,4′-dihydroxydiphenyl sulfone / a salt having an ion exchange group, and R is an alkyl group.)
The process for producing a redox flow battery diaphragm according to claim 7, comprising a polymer having a cross-linking ability and a prepolymer thereof. Preferred (claim 10).

  In order to solve the above-mentioned problems, the present invention provides a resin comprising the matrix, lacquer, other synthetic resins having a hydroxyl group or a naturally-derived resin, and a combination of these resins and an ion exchange resin. It is preferable to use the method for producing a redox flow battery diaphragm according to any one of the above, characterized by comprising at least one of them.

  In order to solve the above-mentioned problems, the present invention provides that the inorganic porous powder particles are diatomaceous earth, sepiolite, zeolite, perlite, calcium silicate, kaolin, attapulgite, vermiculite, cristobalite and other silica porous bodies. Preferably, the method for producing a redox flow battery diaphragm is characterized in that it comprises at least one of the above.

  Since the redox flow battery diaphragm according to the present invention can be stored dry as described above, when the diaphragm is attached to the cell container, it can be operated in a dry space area without working in water. The robot can be automatically assembled by a robot, can be mounted very easily, and does not require a facility such as a work pool, and has an economic effect. In addition to the above-mentioned effects on handling, when an inorganic porous granular material having pores with a pore size of several nanometers such as mesopore diatomaceous earth and sepiolite is used, proton permeability is improved and leakage of polar liquid is improved. There is an effect of reducing liquidity. Furthermore, it is considered possible to apply to fuel cells.

It is explanatory drawing of the cell used for the redox flow battery for performance tests. It is explanatory drawing which shows the redox flow battery for performance tests. It is a manufacturing-process figure of the membrane for redox flow batteries which concerns on Example 1. FIG. It is a manufacturing-process figure of the membrane for redox flow batteries which concerns on Example 2. FIG. It is a manufacturing-process figure of the membrane for redox flow batteries which concerns on Example 3. FIG. It is a manufacturing-process figure of the membrane for redox flow batteries which concerns on Example 4. FIG.

  Modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail below. However, the present invention is not limited to such an embodiment. The membrane for redox flow battery according to the embodiment of the present invention is an inorganic porous material in which an ion exchange resin is attached to the voids and / or the sheet substrate surface of a sheet substrate having a large number of voids communicating with the front and back sides of the sheet. It is characterized by forming an ion exchange membrane in which a granular powder is dispersed in a matrix.

  The sheet base material used in the present embodiment has at least a large number of voids communicating with the front and back sides of the sheet or in the sheet surface direction, can hold the inorganic porous powder particles in the voids, and is compatible with the polar liquid. Although it does not specifically limit as long as it has acid resistance and intensity | strength, As a shape of a base material, what is well-known as base materials of ion exchange membranes, such as a woven / knitted cloth, a nonwoven fabric, a net-like thing, or a porous sheet, is used widely. For example, staple fibers such as polyester fiber, polyethylene fiber, polypropylene fiber, glass fiber, aramid fiber, polyamide fiber, and other synthetic fibers, or natural fibers such as hemp and pulp, or a combination of these short fibers and inorganic porous materials such as diatomaceous earth Examples thereof include a powdery granular material and, if necessary, a binder added to form a sheet by a dry method or a wet method. The mixing ratio of the sheet base material is not particularly limited. For example, the inorganic porous powder is 50 to 70 parts by mass, the fibrous material is 30 to 50 parts by mass, and the binder is 1 to 7 as necessary. What added the mass part is preferable.

  As the inorganic porous powder particles, those having fine pores to which ion exchange resin adheres are preferable, and porous materials such as diatomaceous earth, sepiolite, zeolite, perlite, calcium silicate, kaolin, attapulgite, vermiculite, cristobalite and other silicas. The granular material is preferable. Diatomite and sepiolite are particularly preferred. In addition, natural or artificial silica porous material, for example, silica porous material TMPS (registered trademark) having a honeycomb-shaped uniform mesopore having a pore size diameter of 2 to 50 nm synthesized using a surfactant micelle as a casting mold Etc.

Diatomaceous earth is mainly composed of silicon dioxide (silica SiO ₂ ) and has strong acid resistance and high moisture absorption and release. Especially, mesoporous diatomaceous earth with a pore size of 2 to 50 nm has a specific surface area of 100 m ² / g, which is about 4 times that of ordinary diatomaceous earth. In addition, since the micropore volume is about 5 times larger and the capacity for holding the ion exchange resin in the micropore is large, it is more preferable as a redox flow battery diaphragm. In addition, the calcined mesopore diatomaceous earth improves the proton conductivity because the organic contaminants or combustible contaminants clogged in the fine pores disappear and more ion exchange resin can be taken in and retained in the fine pores.

Sepiolite is mainly composed of hydrous magnesium silicate, contains magnesium oxide and aluminum oxide, etc., has a pore size diameter of 1 to 20 nm, a specific surface area of 230 to 300 m ² / g and a void that is open on the particle surface. Since the particles are connected in a mesh shape inside the particles, the ion exchange resin can be easily held. Sepiolite has a silanol group and adsorbability due to hydrogen bonds with water and organic substances, and it is difficult to swell in the presence of water or a solvent due to covalent bonds, so it has excellent retention of ion exchange resins.

  As the ion exchange resin to be attached to the inorganic porous powder particles contained in the sheet base material, polycondensates having a known ion exchange group can be widely used. For example, negatively charged ion exchange groups include sulfonic acid groups, carboxylic acid groups, phosphonic acid groups, phosphinic acid groups, etc., and positively charged ion exchange groups include pyridinium base, quaternary ammonium base, third There are secondary amine groups, phosphonium groups, and the like. Among these, the sulfonic acid group improves proton conductivity, and the pyridinium base is suitable as the exchange group of the present invention because it has excellent proton selective permeability and both have oxidation resistance. The resin into which these ion exchange groups are introduced may be any resin, but is generally made of a crosslinked polymer that is three-dimensionally crosslinked with, for example, a crosslinking agent in order to prevent swelling or deformation. It is.

  Examples of known monomers having ion exchange groups used in the cation exchange membrane include phenolsulfonic acid, α, β, β′-halogenated vinylsulfonic acid, methacrylic acid, acrylic acid, styrenesulfonic acid, Examples thereof include vinyl sulfonic acid, maleic acid, itaconic acid, styrene phosphonylic acid, maleic anhydride and vinyl phosphoric acid, and salts and esters thereof. Examples of known monomers having ion exchange groups used in anion exchange membranes include, for example, vinyl pyridine, methyl vinyl pyridine, ethyl vinyl pyridine, vinyl pyrrolidone, vinyl carbazole, vinyl imidazole, aminostyrene, alkylamino. Examples thereof include styrene, dialkylaminostyrene, trialkylaminostyrene, methyl vinyl ketone, chloromethyl styrene, acrylic amide, acrylamide, oxime, styrene, vinyl toluene and the like.

  In the present invention, the ion exchange resin may be produced by any method, but in general, a monomer having a functional group or ion exchange group suitable for introduction of an ion exchange group, a crosslinking agent, and a polymerization initiator. Etc. can be produced by adhering to a sheet substrate having the above-mentioned inorganic porous powder or inorganic porous powder and polymerizing it. Or after making the prepolymer etc. of the said polymerization composition adhere to the sheet | seat base material which has an inorganic porous granular material or an inorganic porous granular material, it can manufacture by growing a polymer.

  The polymerization composition obtained by the above or its prepolymer is attached to a sheet substrate having inorganic porous powder or inorganic porous powder and polymerized to be three-dimensionally crosslinked. The method for adhering the polymerization composition or its prepolymer to the sheet substrate is not particularly limited. For example, a known method such as coating, impregnation, or dipping can be used. Alternatively, it may be appropriately selected according to the properties of the polymerization composition or its prepolymer.

（式中、ｍは繰り返し単位を表す０または１以上の整数、ｎは１以上の整数とする。）
（式中、Ｘはイオン交換基を有するフェノール単量体・その塩またはイオン交換基を有する４，４’−ジヒドロキシジフェニルスルホン単量体・その塩、Ｒはアルキル基とする。）
で表される芳香族ポリスルホン系重合体、該重合体のプレポリマーおよび該重合体に架橋が導入された重合体の中の少なくとも何れかを用いることができる。 As the ion exchange resin in the present embodiment, for example,

(In the formula, m is 0 or an integer of 1 or more representing a repeating unit, and n is an integer of 1 or more.)
(In the formula, X is a phenol monomer having an ion exchange group / a salt thereof or 4,4′-dihydroxydiphenylsulfone monomer / an salt having an ion exchange group, and R is an alkyl group.)
At least any one of the aromatic polysulfone-based polymer represented by formula (1), a prepolymer of the polymer, and a polymer in which crosslinking is introduced into the polymer can be used.

The water-soluble phenol polycondensate comprising the above prepolymer comprises a 4,4′-dihydroxydiphenylsulfone monomer and formaldehyde condensation part [(C ₁₃ H ₁₀ O ₄ S) m], an ion exchange group (sulfonic acid). ) Having a block copolymer of (Na) and formaldehyde condensation part [(C ₇ H ₅ NaO ₄ S) n], the latter segment having a sulfonic acid group on the aromatic ring (—SO ₃ H) or a salt thereof (Na) is introduced. Although it does not specifically limit as a manufacturing method of the said water-soluble phenol polycondensate, For example, the method of Unexamined-Japanese-Patent No. 2010-285383 or Unexamined-Japanese-Patent No. 2005-15607 is used.

  The water-soluble phenol polycondensate having an average molecular weight of 10,000 to 20,000 was obtained by diluting an aqueous solution of water-soluble phenol polycondensate having about 30% by mass and water having about 70% by mass with an acetic acid aqueous solution. After immersing the inorganic porous granular material in the diluted liquid and stirring it under reduced pressure as necessary to infiltrate the diluted liquid into the outer peripheral portion and fine pores of the inorganic porous granular material, the excess diluted liquid When the heat treatment is carried out after removing the water, the water-soluble phenol polycondensate is three-dimensionalized and cured by self-crosslinking by heating under acidic conditions to form an ion exchange resin.

  As a result of the formation of an ion exchange membrane in which a large number of inorganic porous powder particles to which the ion exchange resin has adhered dispersed in the matrix are formed in the voids of the sheet base material and the surface of the sheet base material, separation of the ion exchange resin is prevented. As a result, the durability of the liquid can be improved and the leakage of the polar liquid can be prevented. In addition, the affinity between the matrix and the polar liquid is improved by dispersing a large number of inorganic porous particles with ion-exchange resin adhering to the outer periphery and micropores in the matrix having hydroxyl groups such as lacquer. In addition, a large number of proton conducting paths are formed along the outer peripheral surfaces of the granular material and the granular material in the ion-exchange membrane and along the fine pore wall surfaces in the granular material, so that protons are more easily transmitted. It is considered to be.

  The matrix in the present invention refers to a component that can form a coating on the voids of the sheet substrate and the sheet substrate surface, adhesion to the sheet substrate and affinity with the ion exchange resin that is a component of the coating liquid, It is preferable to select from resins that meet conditions such as the ability to suppress the leakage of polar liquid, such as natural lacquer or cashew nut shell oil mainly composed of urushiol. Lacquers containing polymers and other synthetic resins, for example, polyester resins, acrylic resins, urethane resins, vinyl chloride resins, epoxy resins, melamine resins, fluorine resins, which are conventionally used as paint vehicles Resin, silicone resin, butyral resin, phenol resin, vinyl acetate resin, water soluble resin, hydrophilic resin, and mixtures thereof Copolymer coating resins made of modified products, or alkoxysilanes hydrolyzable organic silicon compound and the like of these partial hydrolyzates thereof. Moreover, proton conductivity can be further improved by adding an ion exchange resin to these resins.

  The lacquer used as the matrix in the present embodiment is not particularly limited in type and production area, and general-purpose lacquer can be widely used. In addition to general-purpose lacquer, cashew nut shell oil extracted from cashew husks belonging to the Urushi family is also included. In general, lacquer is refined so that the lacquer solution “Rakumi Urushi” collected from lacquer wood can be used as paint. First of all, "Rakumi Urushi" is filtered under heating to remove dust and bark, and the filtered "Nama-lacquer" is uniformed to give quality and smoothness and luster. What was stirred under heating and adjusted to a moisture content of 3 to 4% is preferable.

  Lacquer is attached to the sheet base material and then dried to form a coating film, but this does not evaporate the water, but the main function of lacquer is under the conditions of moderate temperature and humidity by the action of an enzyme called laccase. This is because the component urushiol is polymerized, and further, a polymer is formed in a network and cured. Moreover, it hardens | cures by baking by heating at around 20-190 degreeC. In the present embodiment, it is preferable to work by using hardening by baking in consideration of shortening of time.

  A coating liquid is prepared by adding an inorganic porous powder granular material in which an ion exchange resin is previously adhered to the lacquer and a dispersion medium, and stirring and mixing them. When the ion-treated substrate is immersed in the coating solution and impregnated with the coating solution, and then dried by heating, the lacquer is cured and the ion exchange resin adheres firmly to the inorganic porous granular material and the sheet substrate. At this time, it is preferable to increase the mixing ratio of the inorganic porous powder as much as possible within a range in which the leakage of the polar liquid does not occur. That is, the higher the mixing ratio of the inorganic porous granular material, the higher the probability of contact between the inorganic porous granular material and the electrolytic solution, and the higher the proton selective permeability.

  Then, in adjustment of a coating liquid, 50-350 mass parts of inorganic porous granular materials (diatomaceous earth) are preferable with respect to 100 mass parts of lacquer. 200 to 300 parts by mass of the inorganic porous powder (diatomaceous earth) is particularly preferable. If the inorganic porous granular material (diatomaceous earth) is less than 50 parts by mass, the proton selective permeability is small, and if it exceeds 350 parts by mass, the inorganic porous granular material (diatomaceous earth) may be separated. Furthermore, it is preferable to add an ion exchange resin material, for example, a phenol aqueous solution shown below in a comparative amount with the addition ratio of lacquer, and add and mix appropriately. The lacquer dispersion medium is not particularly limited, but turpentine oil, ethanol, or a mixed dispersion medium of these and water is preferable. You may use surfactant and a viscosity modifier as needed.

  Examples A method for producing a redox flow battery membrane according to the present invention will be described below with reference to FIGS. 3 to 6, but the present invention is not limited to these examples. In the following examples, as the ion exchange resin material represented by the chemical structural formula (1) of claim 1, in the chemical structural formula (1), m / n = 7 to 9/3 to 1, average molecular weight Was a phenol polycondensate aqueous solution (hereinafter referred to as “phenol aqueous solution”) having a concentration of 10,000 to 20,000 and a concentration of 30% by mass.

First, as shown in FIG. 1, an appropriate amount of acetic acid and water are added to the aqueous phenol solution based on the following formulation to adjust the ion exchange resin dilution so as to be acidic (PH 4 to 4.5). A known sulfuric acid or other acid used for pH adjustment instead of or together with acetic acid may be used.
<Adjustment of ion exchange resin diluent>
Phenol aqueous solution 3 (unit: parts by mass)
Water 100
Acetic acid (concentration 60% by mass) 0.5 (variation)

Next, a sheet base material by a wet method (paper making method) having the following composition is prepared as an aggregate.
The weight of the sheet substrate (100 × 100 mm) is 1.4 to 1.5 g, and the total thickness is 0.25 to 0.35 mm.
<Basic composition of sheet base material>
Diatomaceous earth powder (Mesopore diatomaceous earth, average particle diameter: φ2.5 μm) 60 (unit: part by mass)
(True specific gravity: 2.0 to 2.1, Apparent specific gravity: 0.5 to 0.7)
Synthetic fiber staple (polyester fiber, specific gravity: 1.4) 40

  The sheet base material (S1) is immersed (11) while the ion exchange resin dilution liquid prepared above is heated to 80 to 100 ° C., and the sheet base material is impregnated with the ion exchange resin dilution liquid. Thereafter, the surface was naturally dried (12), heat-treated at 130 to 160 ° C. for about 1 hour (13) and crosslinked to obtain a treated sheet substrate (S2) having an ion exchange resin attached to the sheet substrate.

  Next, the diatomaceous earth powder (K1) is put into the ion exchange resin diluted solution adjusted as described above, and the mixture is stirred and mixed for about 1 hour (14) to adhere the ion exchange resin to the diatomaceous earth powder. If necessary, you may process under reduced pressure. Then, put in a container and heat-treat at 150-170 ° C. for about 1 hour (15). Then, a mass in which the ion exchange resin is fixed to the diatomaceous earth powder is obtained, and this mass is crushed with a ball mill (16), A powdery pretreated diatomaceous earth (K2) was obtained.

According to the following formulation, ion exchange resin (concentration 30% by weight aqueous solution), lacquer, dispersion medium (ethanol), pretreated diatomaceous earth (K2), and surfactant were mixed by stirring (17) to obtain a coating liquid (C).
<Composition of coating liquid>
Pre-treated diatomaceous earth 100 (Unit: parts by mass)
Aqueous phenol 100
Lacquer (specific gravity: 0.44) 35
Dispersion medium (ethanol) 30
Surfactant 0.5

  The treatment sheet substrate (S2) is immersed in the coating solution (C) (18), and the treatment sheet substrate is impregnated with the coating solution. Thereafter, the treated sheet substrate (S2) is pulled up from the coating solution, and the coating solution adhering to the front and back surfaces of the substrate is scraped off with a glass rod, leaving a predetermined thickness on the plane, and then at a temperature of about 20 to 190 ° C. for a predetermined time. Heat drying (19) to obtain a redox flow battery diaphragm (1). The obtained redox flow battery diaphragm sample (100 × 100 mm) had a total thickness of about 1.15 to 1.18 mm and a weight of 4.2 to 4.3 g.

  The application method of the coating liquid is not limited to the dip coating method. For example, the knife coating method, roller coating method, spraying coating method, rotary screen coating method, spread coating method, roll coating method (direct roll coater, Reverse roll coater), equalizer rod coating method, impregnation coating (impregnation method), slash molding method, rotational molding method, cavity molding method, etc. can be used.

  Next, Example 2 will be described with reference to FIG. In Example 1, instead of the ion exchange resin diluent, the sheet base material was impregnated with the following ion exchange resin diatomaceous earth mixture, dried, immersed in 1 to 3% water diluted acetic acid, and then heated at about 80 ° C. for 1 hour. A membrane (1) for redox flow battery was obtained in the same manner as in Example 1 except that (13) the treated sheet substrate (S2) obtained in the above was immersed in a coating liquid (C) having the following composition (18). .

<Preparation of ion exchange resin diatomaceous earth mixture>
Phenol aqueous solution 100 (Unit: parts by mass)
Pretreatment diatomaceous earth 33.2
Water 16.6

<Composition of coating liquid>
Lacquer 100 (67) (Unit: parts by mass)
Pretreatment Diatomite 150 (100)
Dispersion medium (1.3 times water diluted ethanol) 325 (217)

  Next, Example 3 will be described with reference to FIG. In Example 2, after impregnating the ion-exchange resin diatomaceous earth mixed solution into the sheet base material, heat-treating at 130 ° C. for 10 minutes, washing with water and naturally drying the surface (12), and then dipping in the water-diluted acid The treated sheet base material (S2) obtained by pulling up and heating at 130 ° C. for 10 minutes (13) is immersed in the following coating liquid (C). In the same manner as above, a redox flow battery diaphragm (1) was obtained.

<Composition of coating liquid>
Lacquer 60 (150) (unit: parts by mass)
Pretreatment diatomaceous earth 40 (100)
Dispersion medium (1.2 times water diluted ethanol) 120 (300)

  Next, Example 4 will be described with reference to FIG. The sheet base material was impregnated with the following coating liquid (C) and then heated and dried (19). Next, after being immersed in the following ion exchange resin diatomaceous earth mixed solution, it is taken out and dried naturally. Next, it was taken out after being immersed in 5% strength water-diluted acetic acid, and then heated and dried to obtain a redox flow battery diaphragm (1) in the same manner as in Example 2 except for (19).

<Composition of ion exchange resin diatomaceous earth mixture>
Phenol aqueous solution 75 (Unit: parts by mass)
Pretreatment Diatomite 25
Water 10

<Composition of coating liquid>
Lacquer 60 (100) (unit: parts by mass)
Pre-treated diatomaceous earth 60 (100)
Dispersion medium (3 times water diluted ethanol) 360 (600)

  Next, Example 5 will be described. In Example 1, the treated sheet base material (S2) was allowed to stand for 2-3 minutes in this coating liquid (C) and then pulled up repeatedly. The treated liquid was impregnated in the treated sheet base material by repeated 2-3 times, followed by drying by heating. A membrane (1) for a redox flow battery was obtained in the same manner as in Example 1 except that.

  The redox flow battery diaphragm obtained through the above steps is completely different from the one in which an ion exchange resin is attached to the hole formed in the plastic film, like the conventional redox flow battery diaphragm. Since the porous body is impregnated with an ion exchange resin and fixed with natural lacquer or ion exchange resin, it has excellent proton conductivity, suppresses permeation of polar liquid, and can be stored in a dry state. It has excellent battery performance, chemical resistance and durability, and does not need to be stored in a wet state. However, it is the same as in the case of the conventional diaphragm that the diaphragm is attached and immersed in the polar liquid to sufficiently wet the polar liquid in the diaphragm and then charged and discharged.

  Next, the redox flow battery sample obtained above was attached to a redox flow battery, and its performance was confirmed. As shown in FIG. 1, the redox flow battery used for the performance test of the diaphragm includes the redox flow battery diaphragm 1 and a positive electrode frame 3a in which a carbon felt electrode 2 (a positive electrode 2a and a negative electrode 2b) is arranged at the center. A cell 5 sandwiched from both sides by the negative electrode frame 3b and having the bipolar plates 4a and 4b in contact with the outside is used as a structural unit, wiring as shown in FIG. Using. The positive electrode frame 3a and the negative electrode frame 3b are each provided with a suction port 7 and a discharge port 8. The suction ports 7a on the positive electrode frame 3a side are connected to each other by pipes and connected to the positive electrode liquid tank 9a via the positive electrode pump 10a. The discharge ports 8a on the frame 3a side are connected to each other by pipes and connected to the cathode solution tank 9a. Similarly, the suction ports 7b on the negative electrode frame 3b side are connected by pipes and connected to the negative electrode liquid tank 9b via the negative electrode pump 10b, and the discharge ports 8b on the negative electrode frame 3b side are connected by pipes. Connected to the liquid tank 9b. The polar liquid was circulated by the positive electrode pump 10a and the negative electrode pump 10b.

  The redox flow battery diaphragm 1 obtained in the example was set in the redox flow battery for performance test, and when the pump 10 was operated and the redox flow battery diaphragm 1 was sufficiently wetted with the polar liquid, In the meantime, a voltage was applied via an AC / DC converter, and the change in the color of the polar liquid was visually observed. The positive electrode solution and the negative electrode solution are separately sent from the positive electrode solution tank 9a and the negative electrode solution tank 9b to the positive electrode frame 3a side and the negative electrode frame 3b side by the pump 10, respectively. In the initial charge, when a tetravalent vanadium electrolyte is placed in each of the positive electrode liquid tank 9a and the negative electrode liquid tank 9b and the electrolytic reduction starts, vanadium is changed from tetravalent (blue) to pentavalent (pink yellow) at the positive electrode. Oxidized and reduced from tetravalent (blue) to trivalent (blue green) to divalent (black blue) at the negative electrode, and the color changes, so that it can be judged visually.

  When the performance test was carried out by assembling each of the redox flow battery diaphragms obtained in the above-described examples dried and stored in the above-described redox flow battery for performance test in a spatial region, the positive electrode solution was tetravalent for Examples 1 to 5. The color changed from blue to pentavalent pink yellow, and the negative electrode solution changed from tetravalent blue to trivalent blue-green, and further to divalent black blue. The diaphragm obtained in Example 1 did not have a mixed liquid phenomenon due to the flow of the positive electrode liquid and the negative electrode liquid, and the color of the polar liquid changed rapidly. Although the diaphragm obtained in Example 5 is excellent in the effect of suppressing liquid leakage as compared with the diaphragm obtained in Example 1, it takes some time to wet the polar liquid. In addition, the diaphragms of Examples 2 to 4 require some time for wetting of the polar liquid and further takes time to fully charge, but can be dealt with by increasing the voltage of the AC / DC converter. The electromotive force was 1.3 V per unit cell. Thereafter, charging and discharging were repeated a plurality of times, but no performance degradation was observed in any of the diaphragms.

The results obtained by measuring the AC impedance of the redox flow battery diaphragm obtained in Example 1 at the Aichi Industrial Technology Research Institute and determining the proton conductivity are shown below.
Measuring equipment: Potentiometer / galvano with fuel cell evaluation system (FC5100series manufactured by Chino)
Stat (PGSTAT302 made by AUTO LAB)
Resistance value (Ω) 89.33
Film thickness (cm) 0.0456
Distance between electrodes (cm) 0.5
Proton conductivity (S / cm) 0.2455

Moreover, the measured value of the oxidation-reduction potential (ORP) of the polar liquid which measured the positive electrode solution and the negative electrode solution in the said performance test with the oxidation-reduction potentiometer is as follows.
ORP of tetravalent electrode solution (blue) before charging: 380 mV
ORP of pentavalent cathode solution (pink yellow) after charging: 990 mV
ORP of the divalent cathode solution (black blue) after charging: -227 mV

  The membrane for the redox flow battery of the present invention is used as an electrolyte membrane for various fuel cells in addition to the redox flow battery, or in various applications such as electrodialysis, desalting / salting, pharmaceuticals, food processing, plating solvent treatment, waste liquid treatment, etc. Is possible. In addition, the technical scope of the present invention is wide as long as it does not contradict the spirit of the present invention.

  Since the diaphragm for redox flow battery according to the present invention can be stored dry as described above, when attaching the diaphragm to the cell container, it can be operated in the space without working in water, so the installation work is extremely It is easy to use, is economical because it does not require equipment such as a working pool, is extremely useful because it has excellent hydrogen ion permeability, low leakage of metal ions and water, and excellent durability. is there.

1: redox flow battery diaphragm, 2: carbon felt electrode, 2a: positive electrode carbon felt electrode, 2b: negative electrode carbon felt electrode, 3: frame, 3a: positive electrode frame, 3b: negative electrode frame, 4: bipolar plate, 4a: positive electrode Bipolar plate, 4b: negative electrode bipolar plate, 5: cell, 6: cell stack, 7: suction port, 7a: positive electrode suction port, 7b: negative electrode suction port, 8: discharge port, 8: discharge port, 8a: positive electrode discharge port 8b: negative electrode outlet, 9: polar liquid tank, 9a: positive electrode liquid tank, 9b: negative electrode liquid tank, 10: pump, 10a: positive electrode pump, 10b: negative electrode pump,
11: Immersion step, 12: Washing / drying step, 13: Heat treatment step, 14: Stirring and mixing step, 15: Heating step, 16: Crushing step, 17: Stirring and mixing step, 18: Dipping step, 19: Heat drying Process, S1: Sheet base material, S2: Sheet processing base material, K1: Diatomaceous earth powder, K2: Pre-treated diatomaceous earth, C: Coating liquid

Claims (12)

Forms an ion exchange membrane in which an inorganic porous granular material with an ion exchange resin attached is dispersed in a matrix on the surface and / or the surface of the sheet substrate having a large number of voids communicating with the front and back of the sheet. A diaphragm for a redox flow battery. A diaphragm for a redox flow battery comprising an ion exchange membrane in which an inorganic porous granular material to which an ion exchange resin is adhered is dispersed in a matrix. The redox flow battery diaphragm according to claim 1, wherein the ion exchange resin is a polysulfone ion exchange resin. The ion exchange resin is

(In the formula, m is 0 or an integer of 1 or more representing a repeating unit, and n is an integer of 1 or more.)
(In the formula, X is a phenol / ion salt having an ion exchange group or 4,4′-dihydroxydiphenyl sulfone / a salt having an ion exchange group, and R is an alkyl group.)
The diaphragm for a redox flow battery according to claim 1, comprising a polymer into which a cross-linkage represented by formula (1) is introduced. The resin constituting the matrix is composed of at least one of lacquer, a synthetic resin having a hydroxyl group, a naturally derived resin, and a combination of these resins and an ion exchange resin. The diaphragm for redox flow batteries in any one of 1-4. The inorganic porous powder granule is composed of at least one of diatomaceous earth, sepiolite, zeolite, pearlite, calcium silicate, kaolin, attapulgite, vermiculite, cristobalite, and other silica porous bodies. Item 6. The redox flow battery diaphragm according to any one of Items 1 to 5. The step of adhering an ion exchange resin to the inorganic porous powder granule, the step of adjusting a mixed liquid containing the inorganic porous powder granule adhering the ion exchange resin, matrix and dispersion medium, and communicating with the front and back of the sheet A step of filling an inorganic porous powder granule in which the ion exchange resin is adhered to a sheet base material having a large number of voids, and impregnating the mixed liquid into a sheet base material filled with the inorganic porous powder granule A process for producing a redox flow battery diaphragm, comprising: a step of heating and drying a sheet base material impregnated with the mixed solution to form an ion exchange membrane on the sheet base material. A step of adhering to form an ion exchange resin on the inorganic porous granular material, a step of adjusting a mixed liquid containing the inorganic porous granular material to which the ion exchange resin is adhered, a matrix and a dispersion medium, and the mixing And a step of forming an ion exchange membrane by heating and drying after planarizing the liquid. A method for producing a membrane for a redox flow battery. 9. The method for manufacturing a redox flow battery diaphragm according to claim 7, wherein the ion exchange resin is a polysulfone ion exchange resin. The ion exchange resin is

(In the formula, m is 0 or an integer of 1 or more representing a repeating unit, and n is an integer of 1 or more.)
(In the formula, X is a phenol / ion salt having an ion exchange group or 4,4′-dihydroxydiphenyl sulfone / a salt having an ion exchange group, and R is an alkyl group.)
The method for producing a redox flow battery diaphragm according to claim 7, comprising a polymer having a cross-linking ability and a prepolymer thereof. The resin constituting the matrix is composed of at least one of lacquer, a synthetic resin having a hydroxyl group, a naturally derived resin, and a combination of these resins and an ion exchange resin. The manufacturing method of the diaphragm for redox flow batteries in any one of 7-10. The inorganic porous powder granule is composed of at least one of diatomaceous earth, sepiolite, zeolite, pearlite, calcium silicate, kaolin, attapulgite, vermiculite, cristobalite, and other silica porous bodies. Item 12. A method for producing a redox flow battery diaphragm according to any one of Items 7 to 11.

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