KR102248996B1 - Ion exchanging membrane, and energy storage system comprising the same - Google Patents

Abstract

The present invention relates to an ion exchange membrane and an energy storage device including the same, wherein the ion exchange membrane has a polymer membrane including an ion conductor, and a column shape, extending along the height direction of the column, and penetrating the column. It includes a porous metal oxide containing pores.
The ion exchange membrane prevents the penetration of vanadium pentavalent ions by limiting the size of the channel through which vanadium pentavalent ions permeate, thereby improving voltage efficiency and preventing deterioration.

Description

Ion exchange membrane and energy storage device including the same {ION EXCHANGING MEMBRANE, AND ENERGY STORAGE SYSTEM COMPRISING THE SAME}

The present invention relates to an ion exchange membrane and an energy storage device including the same, and more specifically, by limiting the size of a channel through which vanadium pentavalent ions permeate, the penetration of vanadium pentavalent ions is prevented, thereby improving voltage efficiency. It is a deterioration-prevented ion exchange membrane, a method for manufacturing the same, and to an energy storage device including the same.

In order to solve the problem of fossil fuel depletion and environmental pollution, efforts have been made to save fossil fuels or apply renewable energy to more fields by improving use efficiency.

Renewable energy sources such as solar and wind power are being used more efficiently than before, but these energy sources are intermittent and unpredictable. Due to these characteristics, dependence on these energy sources is limited, and the ratio of renewable energy sources among the current primary power sources is very low.

Since a rechargeable battery provides a simple and efficient method of storing electricity, efforts to use it as an intermittent auxiliary power supply or a power source for small home appliances such as laptops, tablet PCs, and mobile phones continue to increase mobility by miniaturizing them.

Among them, a redox flow battery (RFB) is a secondary battery that can be used by storing energy for a long period of time by repeating charging and discharging through an electrochemical reversible reaction of an electrolyte. The stack and the electrolyte tank, which each determine the capacity and output characteristics of the battery, are configured independently of each other, so the design of the battery is free and the installation space is limited.

In addition, the redox flow battery has a load leveling function that can respond to a rapid increase in power demand by installing it in a power plant, power system, or building, and a function of compensating or suppressing a power outage or an instantaneous low voltage, and can be freely combined as needed. It is a very powerful energy storage technology and a system suitable for large-scale energy storage.

The redox flow battery generally consists of two separate electrolytes. One stores the electroactive material in the negative electrode reaction and the other is used for the positive electrode reaction. In an actual redox flow battery, the electrolyte reaction is different between the positive electrode and the negative electrode, and since there is an electrolyte flow phenomenon, a pressure difference occurs between the positive electrode and the negative electrode. In a typical redox flow battery, a full vanadium-based redox flow battery, the reactions of the positive electrode and the negative electrode electrolyte are as shown in Scheme 1 and Scheme 2, respectively.

[Scheme 1]

[Scheme 2]

Therefore, in order to overcome the pressure difference at both electrodes and to exhibit excellent battery performance even when charging and discharging are repeated, an ion exchange membrane with improved physical and chemical durability is required. In the redox flow battery, the ion exchange membrane is a system It is a core material that accounts for about 10% of the price.

As described above, in the redox flow battery, the ion exchange membrane is a key component that determines battery life and price, and for commercialization of the redox flow battery, the selective permeability of ions of the ion exchange membrane is high, so that crossover of vanadium ions is possible. It should be low, its electrical resistance should be low, so its ionic conductivity should be high, and it should be mechanically and chemically stable to have high durability and low price.

On the other hand, polymer electrolyte membranes commercialized as ion exchange membranes have been used for several decades and are being studied steadily. Recently, direct methanol fuel cells (DMFCs) or polymer electrolyte membrane fuel cells (PEMFCs; polymers) Numerous studies on ion exchange membranes have been actively conducted as a medium for transferring ions used in electrolyte membrane fuel cells, proton exchange membrane fuel cells), redox flow cells, and water purification devices.

Currently, a material widely used as an ion exchange membrane is a Nafion™-based membrane, a polymer containing perfluorinated sulfonic acid groups from DuPont in the United States. This membrane has an ionic conductivity of 0.08 S/cm at room temperature, excellent mechanical strength, and chemical resistance when it has a saturated moisture content, and has stable performance as an electrolyte membrane enough to be used in fuel cells for automobiles. In addition, as a similar type of commercial film, Asahi Chemicals' Aciplex-S film, Dow Chemicals' Dow film, Asahi Glass's There are Flemion film, Gore & Associate's GoreSelcet film, etc., and a polymer that is perfluorinated in alpha or beta form by Ballard Power System of Canada Development research is underway.

However, the membranes are expensive and difficult to synthesize, so that mass production is difficult. In addition, ions such as crossover phenomenon in electric energy systems such as redox flow batteries and having low ionic conductivity at high or low temperatures. As an exchange membrane, it has a disadvantage that its efficiency is greatly reduced.

An object of the present invention is to provide an ion exchange membrane in which the penetration of vanadium pentavalent ions is prevented by limiting the size of a channel in which pentavalent vanadium ions permeate, thereby improving voltage efficiency and preventing deterioration.

Another object of the present invention is to provide an energy storage device including the ion exchange membrane.

According to an embodiment of the present invention, a polymer membrane including an ion conductor, and an ion comprising a porous metal oxide having a column shape and extending along the height direction of the column and including a plurality of pores penetrating the column Provide an exchange membrane.

The pore size of the porous metal oxide may be 0.35 nm to 1.2 nm.

The pillar-shaped porous metal oxide may have a height of 3 nm to 200 nm.

The pillar-shaped porous metal oxide may have an aspect ratio of 1:0.1 to 1:1.

The porous metal oxide may be any one selected from the group consisting of silica, organic silica, metal oxides other than silica, and metal oxides other than silica-silica composite.

The porous metal oxide may have a hexagonal column shape in which the plurality of pores are arranged in a hexagonal shape in a cross section in a direction perpendicular to the height direction of the column.

The hexagonal columnar porous metal oxide has a _{hexagonal electron diffraction pattern having a d 100} value of 18 Å or more, and a benzene adsorption capacity (@ 50 torr, 25° C.) of 15 g/100 g (Grams of benzene/grams of porous metal oxide) or more.

The ion exchange membrane may include 0.01 parts by weight to 0.50 parts by weight of the porous metal oxide based on 1 part by weight of the ion conductor.

The porous metal oxide may be mixed with the ion conductor and dispersed in the polymer membrane.

The ion exchange membrane may include a polymer membrane including the ion conductor, and a coating layer disposed on one or both surfaces of the polymer membrane and including the porous metal oxide.

The coating layer including the porous metal oxide may be 0.05 part by volume to 1.0 part by volume with respect to 1 part by volume of the polymer film.

The ion exchange membrane may include a first polymer membrane including the ion conductor, and a second polymer membrane including the ion conductor and the porous metal oxide mixed and dispersed with the ion conductor.

The second polymer membrane may be 0.05 part by volume to 1.0 part by volume with respect to 1 part by volume of the first polymer membrane.

The polymer membrane may include a porous support including a plurality of pores, and the ion conductor filling the pores of the porous support.

According to another embodiment of the present invention, an energy storage device including the ion exchange membrane is provided.

The energy storage device may be a redox flow battery.

The ion exchange membrane of the present invention prevents the penetration of vanadium pentavalent ions by limiting the size of the channel through which vanadium pentavalent ions permeate, thereby improving voltage efficiency and preventing deterioration.

1 is a diagram schematically showing the selective permeation of ions in an ion exchange membrane in which a first polymer membrane and a second polymer membrane are stacked.
2 is a schematic diagram schematically showing an all-vanadium-based redox battery according to another embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

Unless otherwise specified in the specification, an alkyl group includes a primary alkyl group, a secondary alkyl group and a tertiary alkyl group, and a straight chain or branched chain alkyl group having 1 to 10 carbon atoms, and a halogenated alkyl group The pulverized halogenated alkyl group having 1 to 10 carbon atoms, the allyl group is an allyl group having 2 to 10 carbon atoms, the aryl group is an aryl group having 6 to 30 carbon atoms, the alkoxy group is an alkoxy group having 1 to 10 carbon atoms, and the alkyl sulfonyl group is an alkyl having 1 to 10 carbon atoms The sulfonyl group, the acyl group means an acyl group having 1 to 10 carbon atoms, and the aldehyde group means an aldehyde group having 1 to 10 carbon atoms.

Unless otherwise specified in the specification, the amino group includes a primary amino group, a secondary amino group, and a tertiary amino group, and the secondary or tertiary amino group is an amino group having 1 to 10 carbon atoms.

In the present specification, all compounds or substituents may be substituted or unsubstituted unless otherwise specified. Here, substituted means that hydrogen is a halogen atom, a hydroxy group, a carboxyl group, a cyano group, a nitro group, an amino group, a thio group, a methylthio group, an alkoxy group, a nitrile group, an aldehyde group, an epoxy group, an ether group, an ester group, an ester group. , Carbonyl group, acetal group, ketone group, alkyl group, perfluoroalkyl group, cycloalkyl group, heterocycloalkyl group, allyl group, benzyl group, aryl group, heteroaryl group, derivatives thereof, and combinations thereof. It means that it has been replaced by one.

In the present specification, * indicated at both ends of a chemical formula indicates a connection with another adjacent chemical formula.

In the present specification, the ion conductor including a repeating unit represented by one general formula is not only meant to include only repeating units represented by any one of the formulas included in the general formula, but also included in the general formula. It may be meant to include repeating units represented by various types of chemical formulas.

The ion exchange membrane according to an embodiment of the present invention includes a polymer membrane including an ion conductor and a porous metal oxide.

The ion conductor may be a cationic conductor having a cation exchange group such as a proton, or an anion conductor having an anion exchange group such as a hydroxy ion, carbonate, or bicarbonate.

The cation exchange group may be any one selected from the group consisting of a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, an imide group, a sulfonimide group, a sulfonamide group, and a combination thereof, and generally may be a sulfonic acid group or a carboxyl group. have.

The cation conductor includes the cation exchange group, and a fluorine-based polymer containing fluorine in a main chain; Benzimidazole, polyamide, polyamideimide, polyimide, polyacetal, polyethylene, polypropylene, acrylic resin, polyester, polysulfone, polyether, polyetherimide, polyester, polyethersulfone, polyetherimide, poly Hydrocarbon-based polymers such as carbonate, polystyrene, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyarylethersulfone, polyphosphazene or polyphenylquinoxaline; Partially fluorinated polymers such as polystyrene-graft-ethylenetetrafluoroethylene copolymer or polystyrene-graft-polytetrafluoroethylene copolymer; And sulfone imide.

More specifically, when the cationic conductor is a hydrogen ion cationic conductor, the polymers may include a cation exchange group selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a phosphonic acid group, and a derivative thereof in the side chain, and the Specific examples include poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), a copolymer of tetrafluoroethylene and fluorovinyl ether containing a sulfonic acid group, defluorinated sulfurized polyether ketone, or a mixture thereof. Fluorine-based polymer containing; Sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (SPEEK), sulfonated polybenzimi Dazole (sulfonated polybenzimidazole (SPBI)), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene and mixtures thereof Hydrocarbon-based polymers may be mentioned, but the present invention is not limited thereto.

The anion conductor is a polymer capable of transporting an anion such as hydroxy ion, carbonate or bicarbonate, and the anion conductor is commercially available in the form of hydroxide or halide (generally chloride), and the anion conductor is an industrial integer. (water purification), metal separation, or catalytic processes.

As the anionic conductor, a polymer doped with a metal hydroxide may be generally used, and specifically, poly(ethersulfone), polystyrene, a vinyl-based polymer, poly(vinyl chloride), and poly(vinylidene fluoride) doped with a metal hydroxide. , Poly(tetrafluoroethylene), poly(benzimidazole), poly(ethylene glycol), and the like can be used.

For example, the ion conductor may be a hydrocarbon-based polymer including a hydrophilic repeating unit and a hydrophobic repeating unit.

At least one monomer constituting the hydrophilic repeating unit is substituted with the ion exchange group, and the monomer constituting the hydrophobic repeating unit is not substituted with the ion exchange group or is substituted with a small number of ion exchange groups compared to the hydrophilic repeating unit. I can. In addition, although all the monomers constituting the hydrophilic repeating unit may contain the ion exchange group, the hydrophilic repeating unit may be made of a monomer substituted with the ion exchange group and a monomer not substituted with the ion exchange group.

The ionic conductor is a random copolymer in which the hydrophilic repeating unit and the hydrophobic repeating unit are randomly connected, or includes hydrophobic blocks made of hydrophilic blocks made of the hydrophilic repeating units and hydrophobic blocks made of the hydrophobic repeating units. It may be a block copolymer.

More specifically, the ion conductor may include a monomer in which the hydrophilic repeating unit is represented by Formula 2 below.

[Formula 2]

In Formula 2, R ¹¹¹ to R ¹¹⁴ , R ¹²¹ to R ¹²⁴ , R ¹³¹ to R ¹³⁴ and R ¹⁴¹ to R ¹⁴⁴ are each independently a hydrogen atom, a halogen atom, an ion conducting group, an electron ball It may be any one selected from the group consisting of excitation (electron donation group) and electron withdrawing group (electron withdrawing group).

The halogen atom may be any one selected from the group consisting of bromine, fluorine, and chlorine.

As described above, the ion exchange group may be any one cation exchange group selected from the group consisting of a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group, and the cation exchange group may preferably be a sulfonic acid group. In addition, the ion exchange group may be an anion exchange group such as an amine group.

In addition, the electron donating group may be any one selected from the group consisting of an alkyl group, an allyl group, an aryl group, an amino group, a hydroxy group, and an alkoxy group as an organic group that gives electrons, and the electron withdrawing group is an organic group that attracts electrons. As examples, it may be any one selected from the group consisting of an alkyl sulfonyl group, an acyl group, a halogenated alkyl group, an aldehyde group, a nitro group, a nitroso group, and a nitrile group.

The alkyl group may be a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, an amyl group, a hexyl group, a cyclohexyl group, an octyl group, and the like, and the halogenated alkyl group may be a trifluoromethyl group, pentafluoroethyl group, perfluoro It may be a propyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, and the like, the allyl group may be a propenyl group, and the aryl group may be a phenyl group, a pentafluorophenyl group, or the like. The perfluoroalkyl group refers to an alkyl group in which some hydrogen atoms or all hydrogen atoms are substituted with fluorine.

Z ¹¹ is a divalent organic group, and may be -O- or -S-, and preferably -O-.

At this time, in order for the repeating unit including the monomer represented by Formula 2 to become the hydrophilic repeating unit, the R ¹¹¹ to R ¹¹⁴ , R ¹²¹ to R ¹²⁴ , R ¹³¹ to R ¹³⁴ , in the monomer represented by Formula 2 And ^{at least one or more of R 141} to R ¹⁴⁴ may be an ion exchange group.

Specifically, the hydrophilic repeating unit may be represented by the following Formula 2-1 or Formula 2-2.

[Formula 2-1]

In Formula 2-1, the ^{detailed descriptions of R 111} to R ¹¹⁴ , R ¹²¹ to R ¹²⁴ , R ¹³¹ to R ¹³⁴ , R ¹⁴¹ to R ¹⁴⁴ , and Z ¹¹ are the same as described above, so a repetitive description is omitted. do.

R ²¹¹ to R ²¹⁴ , R ²²¹ to R ²²⁴ and R ²³¹ to R ²³⁴ are each independently a hydrogen atom; Halogen atom; An electron donation group selected from the group consisting of an alkyl group, allyl group, aryl group, amino group, hydroxy group and alkoxy group; And an electron withdrawing group selected from the group consisting of an alkyl sulfonyl group, an acyl group, a halogenated alkyl group, an aldehyde group, a nitro group, a nitroso group, and a nitrile group. Since detailed descriptions of the substituents are the same as described above, a repetitive description will be omitted.

Each of X ²¹ and X ²² may independently be a single bond or a divalent organic group. The divalent organic group is a divalent organic group that attracts or releases electrons, specifically -CO-, -SO ₂ -, -CONH-, -COO-, -CR' ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -and -(CH ₂ ) _n -may be any one selected from the group consisting of. In this case, R'is any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, and a halogenated alkyl group, and n may be an integer of 1 to 10. When X ²¹ or X ²² is a single bond, it means that phenyl groups present on both sides of X are directly connected, and a representative example thereof may be a biphenyl group.

Z ²¹ is a divalent organic group, may be -O- or -S-, preferably -O-.

[Formula 2-2]

In Formula 2-2, the ^{detailed description of R 111} to R ¹¹⁴ , R ¹²¹ to R ¹²⁴ , R ¹³¹ to R ¹³⁴ , R ¹⁴¹ to R ¹⁴⁴ , and Z ¹¹ is the same as described above, so a repetitive description is omitted. do.

R ³¹¹ to R ³¹⁴ and R ³²¹ to R ³²⁴ are each independently a hydrogen atom; Halogen atom; Ion conducting group; An electron donation group selected from the group consisting of an alkyl group, allyl group, aryl group, amino group, hydroxy group and alkoxy group; And an electron withdrawing group selected from the group consisting of an alkyl sulfonyl group, an acyl group, a halogenated alkyl group, an aldehyde group, a nitro group, a nitroso group, and a nitrile group. Since detailed descriptions of the substituents are the same as described above, a repetitive description will be omitted.

Wherein X ³¹ is a single bond, -CO-, -SO ₂ -, -CONH-, -COO-, -CR' ₂ -, -(CH ₂ ) _n -, a cyclohexylidene group, a cyclo containing an ion exchange group Selected from the group consisting of a hexylidene group, a fluorenylidene group, a fluorenylidene group including an ion exchange group, -C(CH ₃ ) ₂ -, -C(CF ₃ ) _{2 -, -O-, and -S-} Is any one divalent organic group, wherein R'is any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, and a halogenated alkyl group, and n may be an integer of 1 to 10. Since detailed descriptions of the substituents are the same as described above, a repetitive description will be omitted.

However, in the cyclohexylidene group containing the ion exchange group or the fluorenylidene group containing the ion exchange group, the hydrogen of the cyclohexylidene group or the fluorenylden group is a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, and these It means substituted with any one ion exchange group selected from the group consisting of a combination of.

Z ³¹ is a divalent organic group, and may be -O- or -S-, preferably -O-.

The n ³¹ may be an integer of 0 to 10, preferably 0 or 1.

Meanwhile, the ionic conductor may include a monomer represented by the following formula (3) in the hydrophobic repeating unit.

[Formula 3]

In Chemical Formula 3, since ^{detailed descriptions of R 211} to R ²¹⁴ , R ²²¹ to R ²²⁴ and R ²³¹ to R ²³⁴ , X ²¹ , X ²² and Z ²¹ are the same as described above, a repetitive description will be omitted.

Specifically, the hydrophobic repeating unit may be represented by the following Formula 3-1.

[Chemical Formula 3-1]

In Formula 3-1, the ^{detailed descriptions of R 211} to R ²¹⁴ , R ²²¹ to R ²²⁴ and R ²³¹ to R ²³⁴ , X ²¹ , X ²² and Z ²¹ are the same as described above, so a repetitive description will be omitted. .

R ⁴¹¹ to R ⁴¹⁴ and R ⁴²¹ to R ⁴²⁴ are each independently a hydrogen atom; Halogen atom; An electron donation group selected from the group consisting of an alkyl group, allyl group, aryl group, amino group, hydroxy group and alkoxy group; And an electron withdrawing group selected from the group consisting of an alkyl sulfonyl group, an acyl group, a halogenated alkyl group, an aldehyde group, a nitro group, a nitroso group, and a nitrile group. Since detailed descriptions of the substituents are the same as described above, a repetitive description will be omitted.

X ⁴¹ is a single bond, -CO-, -SO ₂ -, -CONH-, -COO-, -CR' ₂ -, -(CH ₂ ) _n -, cyclohexylidene group, fluorenylidene group, -C (CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -O- and -S- is any one divalent organic group selected from the group consisting of, and R'is a hydrogen atom, a halogen atom, an alkyl group, and Any one selected from the group consisting of a halogenated alkyl group, and n may be an integer of 1 to 10. Since detailed descriptions of the substituents are the same as described above, a repetitive description will be omitted.

Z ⁴¹ is a divalent organic group, may be -O- or -S-, preferably -O-.

The n ⁴¹ may be an integer of 0 to 10, preferably 0 or 1.

In addition, the ion conductor may include a monomer in which the hydrophobic repeating unit is represented by Formula 4 below.

[Formula 4]

In Formula 4, R ⁵¹¹ to R ⁵¹³ are each independently a hydrogen atom; Halogen atom; An electron donation group selected from the group consisting of an alkyl group, allyl group, aryl group, amino group, hydroxy group and alkoxy group; And an electron withdrawing group selected from the group consisting of an alkyl sulfonyl group, an acyl group, a halogenated alkyl group, an aldehyde group, a nitro group, a nitroso group, and a nitrile group. Since detailed descriptions of the substituents are the same as described above, a repetitive description will be omitted.

Z ⁵¹ is a divalent organic group, and may be -O- or -S-, preferably -O-.

Specifically, the hydrophobic repeating unit may be represented by the following Formula 4-1.

[Formula 4-1]

In Formula 4-1, since ^{specific descriptions of R 511} to R ⁵¹³ , and Z ⁵¹ are the same as described above, a repetitive description will be omitted.

R ⁶¹¹ to R ⁶¹⁴ and R ⁶²¹ to R ⁶²⁴ are each independently a hydrogen atom; Halogen atom; An electron donation group selected from the group consisting of an alkyl group, allyl group, aryl group, amino group, hydroxy group and alkoxy group; And an electron withdrawing group selected from the group consisting of an alkyl sulfonyl group, an acyl group, a halogenated alkyl group, an aldehyde group, a nitro group, a nitroso group, and a nitrile group. Since detailed descriptions of the substituents are the same as described above, a repetitive description will be omitted.

X ⁶¹ is a single bond, -CO-, -SO ₂ -, -CONH-, -COO-, -CR' ₂ -, -(CH ₂ ) _n -, cyclohexylidene group, fluorenylidene group, -C (CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -O- and -S- is any one divalent organic group selected from the group consisting of, and R'is a hydrogen atom, a halogen atom, an alkyl group, and Any one selected from the group consisting of a halogenated alkyl group, and n may be an integer of 1 to 10. Since detailed descriptions of the substituents are the same as described above, a repetitive description will be omitted.

Each of Z ⁶¹ is independently a divalent organic group, and may be -O- or -S-, preferably -O-.

The n ⁶¹ may be an integer of 0 to 10, and preferably may be an integer of 0 or 1.

On the other hand, the ion conductor may include a monomer represented by the following formula 5-1 in the hydrophobic repeating unit.

[Chemical Formula 5-1]

In Formula 5-1, the R ³¹¹ to R ³¹⁴ , R ³²¹ to R ³²⁴ , R ⁴¹¹ to R ⁴¹⁴ , R ⁴²¹ to R ⁴²⁴ , X ³¹ , X ⁴¹ , Z ³¹ , Z ⁴¹ , n ³¹ , and n ⁴¹ Since the detailed description of is the same as described above, a repetitive description will be omitted. However, in this case, X ³¹ and X ⁴¹ may be different from each other.

In order for the repeating unit represented by Formula 3-1, Formula 4-1, and Formula 5-1 to become a hydrophobic repeating unit, in the repeating units represented by Formulas 3-1, 4-1, and 5-1, R ²¹¹ to R ²¹⁴ , R ²²¹ to R ²²⁴ , R ²³¹ to R ²³⁴ , R ³¹¹ to R ³¹⁴ , R ³²¹ to R ³²⁴ , R ⁴¹¹ to R ⁴¹⁴ , R ⁴²¹ to R ⁴²⁴ , R ⁵¹¹ to R ⁵¹³ , R ⁶¹¹ It is preferable that to R ⁶¹⁴ and R ⁶²¹ to R ⁶²⁴ substantially do not contain an ion exchange group. Here, the meaning of substantially not including an ion exchange group means that the substituents may contain a small amount of an ion exchange group, but the quantity does not interfere with the phase separation between the hydrophilic region and the hydrophobic region.

Meanwhile, the ionic conductors may each independently further include a monomer in which the hydrophilic repeating unit or the hydrophobic repeating unit is represented by Formula 6 below.

When the ion conductor further includes a monomer represented by Formula 6, the ion conductor includes a nitrogen-containing aromatic ring group in the main chain, thereby improving durability against radical attack and an acid-base interaction. Accordingly, the ion conductor does not cause an addition reaction to the aromatic ring of the ion exchange membrane or breakage of the aromatic ring due to the attack of radicals formed on the cathode side, and the function of the ion exchange group is maximized, so that it is in a low-humidity state. Can improve the driving performance of the car.

[Formula 6]

In Formula 6, Z may be -O- or -S-, preferably -O-.

Y is a divalent nitrogen-containing aromatic cyclic group. The nitrogen-containing aromatic ring group means containing at least one nitrogen atom as a hetero atom in the aromatic ring. In addition, an oxygen atom, a sulfur atom, and the like may be included as other heteroatoms together with the nitrogen atom.

Specifically, the divalent nitrogen-containing aromatic cyclic group is pyrrole, thiazole, isothiazole, oxazole, isoxazole, imidazole, imidazoline, imidazolidine, pyrazole, triazine, pyridine, pyrimidine, Pyridazine, pyrazine, indole, quinoline, isoquinoline, tetrazole, tetrazine, triazole, carbazole, quinoxaline, quinazoline, indolizine, isoindole, indazole, phthalazine, naphthyridine, bipyridine, benz It may be a divalent group of any one nitrogen-containing aromatic ring compound selected from the group consisting of imidazole, imidazole, pyrrolidine, pyrroline, pyrazoline, pyrazolidine, piperidine, piperazine, and indoline.

The ion conductor may have a weight average molecular weight of 10,000 g/mol to 1,000,000 g/mol, and preferably may have a weight average molecular weight of 100,000 g/mol to 500,000 g/mol. When the weight average molecular weight of the ion conductor is less than 100,000 g/mol, it is difficult to form a uniform film and durability may decrease. When the weight average molecular weight of the ion conductor exceeds 500,000 g/mol, solubility may decrease.

The ionic conductor may be prepared by preparing the hydrophilic repeating unit and the hydrophobic repeating unit, respectively, and then performing a nucleophilic substitution reaction between the hydrophilic repeating unit and the hydrophobic repeating unit.

In addition, the hydrophilic repeating unit and the hydrophobic repeating unit may also be prepared by a nucleophilic substitution reaction. For example, when the hydrophilic repeating unit is a repeating unit represented by Chemical Formula 2-2, the Chemical Formula 2-2 It can be prepared by an aromatic nucleophilic substitution reaction of two components of the active dihalide monomer and the dihydroxide monomer constituting the repeating unit represented by, and the hydrophobic repeating unit is a repeating unit represented by Formula 3-1. In the case of, it can be prepared by an aromatic nucleophilic substitution reaction between the active dihalide monomer of the two components and the dihydroxide monomer constituting the repeating unit represented by Chemical Formula 3-1.

For example, when the hydrophilic repeating unit is a repeating unit represented by Formula 2-2, as the active dihalide monomer, SDCDPS (sulfonated dichlorodiphenyl sulfone), SDFDPS (sulfonated difluorodiphenyl sulfone), SDCDPK (sulfonated dichlorodiphenyl ketone), DCDPS ( dichlorodiphenyl sulfone), DFDPS (difluorodiphenyl sulfone or Bis-(4-fluorophenyl)-sulfone) or DCDPK (dichlorodiphenyl ketone), etc., as the active dihydroxy monomer SHPF (sulfonated 9,9'-bis (4-hydroxyphenyl) fluorine or sulfonated 4,4'-(9-Fluorenylidene biphenol)) or HPF(9,9'-bis(4-hydroxyphenyl)fluorine or 4,4'-(9-Fluorenylidene biphenol)) I can.

In addition, when the hydrophobic repeating unit is a repeating unit represented by Formula 3-1, 1,3-bis(4-fluorobenzoyl)benzene (1,3-bis(4-fluorobenzoyl) as the active dihalide monomer benzene), etc., as the active dihydroxy monomer, dihydroxydiphenyl sulfone (DHDPS), dihydroxydiphenyl ketone or dihydroxybenzophenone (DHDPK), or BP (4,4'-biphenol), etc., can be prepared by a nucleophilic substitution reaction.

In addition, when the hydrophobic repeating unit is a repeating unit represented by Formula 4-1, as the active dihalide monomer, 2,6-difluorobenzonitrile, etc., and the active dihydroxy monomer DHDPS (dihydroxydiphenyl sulfone), DHDPK (dihydroxydiphenyl ketone or dihydroxybenzophenone) or BP (4,4'-biphenol) can be prepared by a nucleophilic substitution reaction.

Likewise, in the case of nucleophilic substitution reaction between the prepared hydrophilic repeating unit and the hydrophobic repeating unit, both ends of the hydrophilic repeating unit are hydroxyl groups, and both ends of the hydrophobic repeating unit are controlled by a halide group, or the hydrophobic repeating unit When both ends of the unit are hydroxy groups and both ends of the hydrophilic repeating unit are controlled by a halide group, the hydrophilic repeating unit and the hydrophobic repeating unit can be subjected to a nucleophilic substitution reaction.

At this time, the nucleophilic substitution reaction may be preferably carried out in the presence of an alkaline compound. The alkaline compound may be specifically sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate or sodium hydrogen carbonate, and one of them may be used alone or in combination of two or more.

In addition, the nucleophilic substitution reaction may be carried out in a solvent. In this case, as the solvent, specifically, N,N-dimethyl acetamide, N,N-dimethyl formamide, N-methyl ( Aprotic polar solvents such as methyl)-2-pyrrolidone, dimethyl sulfoxide, sulfolane, or 1,3-dimethyl-2-imidazolidinone These may be mentioned, and one of them may be used alone or in combination of two or more.

At this time, together with the aprotic solvent, benzene, toluene, xylene, hexane, cyclohexane, octane, chloro benzene, dioxane ( dioxane), tetrahydrofuran, anisole, and a solvent such as phenethyl may coexist.

Optionally, it may further comprise introducing an ion exchange group into the ion conductor. For example, when the ion exchange group is a sulfonic acid group, which is a cation exchange group, the step of introducing the ion exchange group into the ion conductor may include the following two methods.

First, when preparing the hydrophilic repeating unit of the ion conductor, it is a method of introducing an ion exchange group into a polymer prepared by polymerization using a monomer already containing an ion exchange group. In this case, as a monomer of the nucleophilic substitution reaction, SDCDPS (sulfonated dichlorodiphenyl sulfone) containing an ion exchange group, SDFDPS (sulfonated difluorodiphenyl sulfone), SDCDPK (sulfonated dichlorodiphenyl ketone), or SHPF (sulfonated 9,9'-bis ( 4-hydroxyphenyl)fluorine or sulfonated 4,4'-(9-Fluorenylidene biphenol)) can be used.

In addition, in this case, a monomer having a sulfonic acid ester group is reacted instead of the sulfonic acid group to prepare the polymer having the sulfonic acid ester group, and then the sulfonic acid ester is deesterified by the sulfonic acid ester group. A method of converting a group to a sulfonic acid group can also be used.

Second, an ion exchange group may be introduced into the hydrophilic repeating unit by preparing a polymer using a monomer not containing the ion exchange group and then sulfonating it using a sulfonating agent.

Sulfuric acid may be used as the sulfonating agent, but as another example, the prepared polymer is used in the presence of an excess of chlorosulfonic acid (1 to 10 times, preferably 4 to 7 times the total weight of the polymer). An ion conductor having hydrogen ion conductivity may be prepared by performing a reaction in a chlorinated solvent such as dichloromethane, chloroform, or 1,2-dichloroethane.

When the ion conductor includes a sulfonic acid group as an ion exchange group, the ion conductor may have a sulfonation degree of 1 to 100 mol%, preferably 50 to 100 mol%. That is, the ion conductor may be 100 mol% sulfonation at a site that can be sulfonated, and even if 100 mol% sulfonation is performed, dimensional stability and durability are not reduced due to the structure of the block copolymer of the ion conductor. Does not have an effect. In addition, when the ion conductor has a degree of sulfation in the above range, excellent ionic conductivity may be exhibited without deteriorating dimensional stability.

When the ion conductor includes the hydrophilic repeating unit and the hydrophobic repeating unit, after primary synthesis of the hydrophilic repeating unit and the hydrophobic repeating unit in an oligomer state, the hydrophilic repeating unit and the hydrophobic repeating unit are desired. By synthesizing to have a molar ratio, it is possible to easily control the structure, and through this, the characteristics as an ion conductor can be easily controlled. The structure-controlled ion conductor may provide an ion conductor having improved ionic conductivity and durability within all humidification ranges due to fine phase separation between the hydrophilic repeating unit and the hydrophobic repeating unit.

At this time, the molar ratio of the hydrophilic repeating unit and the hydrophobic repeating unit means the number of moles of the hydrophobic repeating unit that the ion conductor contains per 1 mole of the hydrophilic repeating unit, and the ion conductor is the hydrophilic repeating unit and the hydrophobic repeating unit The molar ratio of 1: 0.5 to 1: 10 may be, specifically 1: 1 to 1: 5 may be, and more specifically 1: more than 1.2 to 1: 5 may be. When the molar ratio of the hydrophobic repeating unit is less than 0.5, the moisture content increases, thereby reducing dimensional stability and durability, and when it exceeds 10, ionic conductivity performance may not be expressed.

Meanwhile, the polymer membrane may be in the form of a single membrane made of the ion conductor, or may be in the form of a reinforced membrane in which the ion conductor is supported by a porous support.

When the polymer membrane is in the form of a reinforced membrane, the polymer membrane may include a porous support including a plurality of pores, and the ion conductor filling the pores of the porous support.

The porous support may include, as an example, a perfluorinated polymer having excellent resistance to thermal and chemical decomposition. For example, the porous support is polytetrafluoroethylene (PTFE) or tetrafluoroethylene and CF ₂ =CFC _n F _2n+1 (n is an integer of 1 to 5) or CF ₂ =CFO-(CF ₂ CF (CF ₃ )O) It _{may be a copolymer with m} C _n F _2n+1 (m is an integer of 0 to 15, n is an integer of 1 to 15).

Since the PTFE is commercially used, it can be suitably used as the porous support. In addition, expanded polytetrafluoroethylene polymer (e-PTFE) having a microstructure of a polymer fibrils or a microstructure in which nodes are connected to each other by fibrils can also be suitably used as the porous support, and the nodes do not exist. Films having a microstructure of non-polymeric fibrils can also be suitably used as the porous support.

The porous support comprising the perfluorinated polymer can be produced by extrusion-molding dispersion-polymerized PTFE on a tape in the presence of a lubricant, and stretching the material thus obtained to form a more porous and stronger porous support. In addition, by heat-treating the e-PTFE at a temperature exceeding the melting point of the PTFE (about 342 °C), the amorphous content of PTFE may be increased. The e-PTFE film prepared by the above method may have microporosity and porosity having various diameters. The e-PTFE film prepared by the above method may have at least 35% pores, and the diameter of the micropores may be about 0.01 μm to 1 μm. In addition, the thickness of the porous support including the perfluorinated polymer can be varied in various ways, for example, it may be 2 µm to 40 µm, preferably 5 µm to 20 µm. If the thickness of the porous support is less than 2 µm, mechanical strength may be significantly lowered, whereas if the thickness exceeds 40 µm, resistance loss increases, and weight reduction and integration may fall.

As another example of the porous support, the porous support may be a nonwoven fibrous web composed of a plurality of randomly oriented fibers.

The non-woven fibrous web is interlaid, but refers to a sheet having a structure of individual fibers or filaments, not in the same manner as a woven fabric. The nonwoven fibrous web includes carding, garneting, air-laying, wet-laying, melt blowing, spunbonding, and stitch bonding ( It can be manufactured by any one method selected from the group consisting of stitch bonding).

The fibers may include one or more polymer materials, and any one may be used as long as it is generally used as a fiber-forming polymer material, and specifically, a hydrocarbon-based fiber-forming polymer material may be used. For example, the fiber-forming polymeric materials may be polyolefins such as polybutylene, polypropylene and polyethylene; Polyesters such as polyethylene terephthalate and polybutylene terephthalate; Polyamides (nylon-6 and nylon-6,6); Polyurethane; Polybutene; Polylactic acid; Polyvinyl alcohol; Polyphenylene sulfide; Polysulfone; Fluid crystalline polymers; Polyethylene-co-vinyl acetate; Polyacrylonitrile; Cyclic polyolefin; Polyoxymethylene; Polyolefin-based thermoplastic elastomers; And any one selected from the group consisting of combinations thereof, but is not limited thereto.

As another example of the porous support in the form of a nonwoven fibrous web, the porous support may include a nanoweb in which nanofibers are integrated into a nonwoven fabric including a plurality of pores.

The nanofibers exhibit excellent chemical resistance, have hydrophobicity, and may preferably use a hydrocarbon-based polymer that does not have a fear of shape deformation due to moisture in a high humidity environment. Specifically, the hydrocarbon-based polymer includes nylon, polyimide, polyaramid, polyetherimide, polyacrylonitrile, polyaniline, polyethylene oxide, polyethylene naphthalate, polybutylene terephthalate, styrene butadiene rubber, polystyrene, polyvinyl chloride, Polyvinyl alcohol, polyvinylidene fluoride, polyvinyl butylene, polyurethane, polybenzoxazole, polybenzimidazole, polyamideimide, polyethylene terephthalate, polyphenylene sulfide, polyethylene, polypropylene, copolymers thereof , And a mixture thereof may be used selected from the group consisting of, among them, a polyimide having more excellent heat resistance, chemical resistance, and morphological stability may be preferably used.

The nanoweb is an aggregate of nanofibers in which nanofibers produced by electrospinning are randomly arranged. At this time, the nanofibers were calculated from the average by measuring the diameter of 50 fibers using a scanning electron microscope (JSM6700F, JEOL) in consideration of the porosity and thickness of the nanoweb, 40 nm to 5000 nm. It is preferable to have an average diameter of. If the average diameter of the nanofibers is less than 40 nm, the mechanical strength of the porous support may be reduced, and if the average diameter of the nanofibers exceeds 5,000 nm, the porosity may be significantly decreased and the thickness may be increased.

The thickness of the nonwoven fibrous web may be 10 µm to 50 µm, and specifically 15 µm to 43 µm. When the thickness of the nonwoven fibrous web is less than 10 μm, mechanical strength may decrease, and when it exceeds 50 μm, resistance loss may increase, and weight reduction and integration may decrease.

The nonwoven fibrous web may have a basic weight of 5 g/m ² to 30 g/m ² . When the basis weight of the nonwoven fibrous web is ^{less than 5 g/m 2} , visible pores may be formed and thus it may be difficult to function as a porous support, and ^{when it exceeds 30 g/m 2} , paper or fabric with almost no pores formed It can be manufactured in the form of

The porosity of the porous support may be 45% or more, and specifically 60% or more. On the other hand, it is preferable that the porous support has a porosity of 90% or less. If the porosity of the porous support exceeds 90%, morphological stability is deteriorated, so that the post-process may not proceed smoothly. The porosity can be calculated by the ratio of the air volume to the total volume of the porous support according to Equation 1 below. At this time, the total volume is calculated by preparing a rectangular sample and measuring the width, length, and thickness, and the air volume can be obtained by subtracting the polymer volume inverted from the density after measuring the mass of the sample.

[Equation 1]

Porosity (%) = (air volume in porous support/total volume of porous support) X 100

The ion exchange membrane is an ion exchange membrane in the form of a reinforced composite membrane in which an ion conductor is filled in the pores of the porous support.

When the polymer membrane is in the form of the reinforced membrane, the polymer membrane may further include an ion conductor layer positioned on one or both sides of the porous support. The ion conductor layer fills the pores of the porous support when the polymer membrane in the form of the reinforcement membrane is prepared, and then the ion conductor remaining after filling the pores of the porous support is coated on one or both surfaces of the porous support. The ion conductor layer may be formed.

In addition, when the ion conductor is a hydrocarbon-based copolymer composed of a hydrophilic repeating unit and a hydrophobic repeating unit as illustrated above, it is advantageous in terms of stability of the ion exchange membrane to use a hydrocarbon-based porous support as the porous support. Specifically, when a porous support having different properties and an ionic conductor are combined, for example, when a fluorine-based porous support and a hydrocarbon-based ion conductor are combined, the ion conductor may be easily detached or discharged from the porous support, or impregnation may be poor.

Meanwhile, the size of the hydronium ions formed in the process of transporting hydrogen ions (H ⁺ ) through the ion exchange membrane is about 320 pm, and the vanadium pentavalent ions (VO ₂ ⁺ ) that affect the deterioration of the polymer and the voltage efficiency. The size of is about 1.15 nm. The size of the ion cluster formed during operation of the redox flow battery is 2 nm to 3 nm, and has a size that allows the vanadium pentavalent ions to pass in addition to the hydronium ions to be transferred. This causes permeation of vanadium ions, causing a deterioration reaction in the ion exchange membrane, or lowering voltage efficiency. In the present invention, the porous metal oxide is used to limit the size of the passage through which the vanadium pentavalent ions move, thereby preventing the penetration of vanadium ions.

Specifically, the porous metal oxide may _{have micropores similar to the size (1.15 nm) of the vanadium pentavalent ions (VO 2} ⁺ ), thereby preventing the penetration of the vanadium ions. Meanwhile, since the pore size of the porous metal oxide is larger than the size of the proton or hydronium ion to be transferred (< 0.32 nm), ions can be selectively transmitted. Accordingly, the porous metal oxide may have a pore size of 0.35 nm to 1.2 nm, and specifically 0.5 nm to 1 nm.

As the porous metal oxide having the pore size, a silica-based metal oxide such as silica or organic silica, or a metal oxide other than the silica such as zirconia, alumina, titania, silica or ceria, zeolite, alumina-silica, titania -Any one selected from the group consisting of silica or metal oxide-silica composites such as ceria-silica may be exemplified. The organic silica includes all silicas in which an aliphatic compound or an aromatic compound is included in the repeating unit.

The porous metal oxide may have a pillar shape. In this case, the pores may extend along the height direction of the pillar and may be formed to penetrate through the pillar. When the porous metal oxide has a columnar shape as described above, extends along the height direction of the column and includes a plurality of pores penetrating the column, the degree of permeation of vanadium ions may be further adjusted according to the arrangement direction. That is, when the direction of the pores and the movement path of ions do not coincide, the permeation of vanadium ions can be further prevented when the porous metal oxide is disposed. On the other hand, when the pores are formed in a random direction, the above-described additional effect cannot be obtained.

The columnar shape means a shape other than a spherical shape, and can be any shape as long as the edge between the surface and the surface is observed. However, here, even if the surface is not completely flat, it is sufficient as long as it can be substantially recognized as a surface, and even if the corner is not completely chamfered and is rounded, it is sufficient as long as it can be substantially recognized as an edge.

For example, the column shape may be any one shape selected from the group consisting of a circular column, a square column, a pentagonal column, a hexagonal column, a heptagonal column, an octagonal column, and similar shapes thereof, preferably a hexagonal column shape. I can. Here, for example, the similar shape of a hexagonal column refers to a shape that can be recognized as a substantially hexagonal column shape as a case in which the top, bottom and main six corners are observed, even if the shape of the hexagonal column is not a complete hexagonal column shape.

The columnar porous metal oxide may have a height of 3 nm to 200 nm, and specifically, a height of 4 nm to 50 nm. The height of the columnar shape means the length of the side surface. When the height of the columnar shape is less than 3 nm, the transmission of vanadium ions may not be effectively prevented, and when the height of the columnar shape exceeds 200 nm, oxides in the ion exchange membrane may act as foreign substances, thereby reducing physical properties.

The pillar-shaped porous metal oxide may have an aspect ratio of 1:0.1 to 1:1, and specifically, an aspect ratio of 1:0.5 to 1:1. When the aspect ratio of the columnar shape is less than 1:0.1, the pores may not have a uniform structure.

In this case, the porous metal oxide extends along the height direction of the pillar and includes pores formed to penetrate the pillar. The porous metal oxide extends along the height direction of the pillar and may include pores extending in a direction perpendicular to the height direction of the pillar or not penetrating the pillar, in addition to pores formed to penetrate the pillar. The oxide extends along the height direction of the pillar and includes at least a plurality of pores formed to pass through the pillar.

As described above, the pores may have a pore size of 0.35 nm to 1.2 nm, specifically 0.5 nm to 1 nm, so that the vanadium pentavalent ions do not pass and the proton or hydronium ions selectively pass. Can be

The porous metal oxide may have a hexagonal column shape in which the plurality of pores are arranged in a hexagonal shape in a cross section in a direction perpendicular to the height direction of the column. Arrangement of the pores in a hexagonal shape means not only mathematically perfect hexagonal symmetry, but also includes those having a significant observable deviation from this abnormal state. For example, the pores arranged in a hexagonal shape may be surrounded by six nearest neighboring pores. However, depending on the quality of the porous metal oxide due to defects and imperfections during manufacturing, a significant number of pores may violate this standard. Therefore, if the number of pores surrounded by six nearest neighboring pores in the porous metal oxide is 50% by number or more, specifically 75% by number or more of the total number of pores, it may be included in the definition of the hexagonal column shape.

The porous metal oxide in which the pores are arranged in a hexagonal shape shows an X-ray diffraction pattern having several distinct maximum values, and the positions of the peaks are of the hkO reflection from the hexagonal grid. Roughly corresponds to the location. In addition, the microstructure of the porous metal oxide in which the pores are arranged in a hexagonal shape may be confirmed through a transmission electron microscope and electron diffraction. The porous metal oxide in which the pores are arranged in a hexagonal shape shows a hexagonal arrangement of large pores, and an electron diffraction pattern corresponding thereto shows a hexagonal arrangement.

Specifically, the d ₁₀₀ value of the electron diffraction pattern is the distance between adjacent spots in the hkO projection of the hexagonal grating, and by observing the _{repeat distance a o between the pores in the electron micrograph, d It} can be obtained through the formula 100 = a _{o √(3/2).} Accordingly, the porous metal oxide in which the measured pores are arranged in a hexagonal shape may have a hexagonal electron diffraction pattern having a _{d 100 value of 18 Å or more.}

_{In addition, the value of d 100} in the electron diffraction pattern corresponds to d-spacing of the low angle peak in the X-ray diffraction pattern of the material, and the porous metal oxide in which the pores are arranged in a hexagonal shape is 10 It is possible to have an X-ray diffraction pattern having two or more peaks at a position greater than Å unit d-spacing (8.842 degrees two-theta for Cu K-alpha radiation). At least one of the two or more peaks is at a position greater than 18 Å unit d-spacing, and at a position less than 10 Å unit d-spacing, there may be no peak having a relative intensity of about 20% or more of the strongest peak.

The X-ray diffraction data can be measured in the Scintag PAD X automatic diffraction system using theta geometry, Cu K-alpha radiation and energy dispersive X-ray detector. have. At this time, both the incident ray and the diffracted X-ray ray may be collimated by a double slit incident and diffraction collimation system. The sizes of the slits are 0.5 mm, 1.0 mm, 0.3 mm and 0.2 mm, respectively. Further, the diffraction data can be recorded by step scan at 0.04 degrees of 2θ, where θ is the Bragg angle, and the counting time for each step is 10 seconds.

In addition, the porous metal oxide in which the pores are arranged in a hexagonal shape may have a benzene adsorption capacity (@ 50 torr, 25° C.) of 15 g/100 g (grams of benzene/grams of porous metal oxide) or more. The benzene adsorption capacity can be determined by treating the porous metal oxide with the pores arranged in a hexagonal shape with benzene until equilibrium is reached at 25° C. and 50 torr, and then the weight of the adsorbed benzene can be measured. Optionally, before measuring the benzene adsorption capacity, the porous metal oxide having the pores arranged in a hexagonal shape may be dehydrated or calcined, and the firing may be performed at 540° C. for 1 hour, for example.

The porous metal oxide in which the pores are arranged in a hexagonal shape is, for example, alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) in a weight ratio of 0: 1 to 0.5: 1, specifically 0.001: 1 to 0.5: 1 It can be prepared by crystallizing the containing reactant at a temperature of 25°C to 175°C, specifically 50°C to 150°C. At this time, it is preferable that the pH is maintained between 9 and 14.

A silicon source may be used in place of the silica, and an organic silicate such as quaternary ammonium silicate may be used as the silicon source, and specifically tetra methyl ammonium silicate or tetra ethyl ortho silicate may be exemplified.

In addition, the reactant for preparing a porous metal oxide in which the pores are arranged in a hexagonal shape may further include an alkali metal or an alkaline earth metal (M), or an organic inducing additive (R) together with the reactant including the alumina and silica. In addition, the reactant may be dissolved in a solvent such as _{the C 1} to C ₆ alcohol, C ₁ to C _{6 diol and/or water.}

The alkali metal or alkaline earth metal (M) may be, for example, sodium, potassium, magnesium, or calcium. The organic inducing additive (R) assists in the formation of a crystal structure, and functions as a template of the reactant in the process of nucleation and growth. Non-limiting examples of organic inducing additives capable of this function include cetyl trimethyl ammonium, cetyl trimethyl phosphonium, octadecyl trimethyl phosphonium, benzyl trimethyl ammonium, cetyl pyridinium, myristyl trimethyl ammonium, decyl trimethyl ammonium, dodecyl trimethyl Ammonium and dimethyl didodecyl ammonium, and the like.

The alkali metal or alkaline earth metal (M) may have an oxide molar ratio of M _{2 /e} O/(SiO ₂ +Al ₂ O ₃ ) of 0 to 5, and specifically 0 to 3. E is the weighted average valence of M. In addition, the organic induction additive (R) may have an oxide molar ratio of R _{2 /f} O/(SiO ₂ +Al ₂ O ₃ ) of 0.01 to 2, and specifically 0.03 to 1. F is the weighted average valency of R.

Specifically illustrating an example of a method of manufacturing a porous metal oxide in which the pores are arranged in a hexagonal shape, _{the molar ratio of the solvent/R 2 /f} O to the organic inducing additive (R) is 50 to 800, specifically 50 to 500 The mixture is mixed to prepare a primary mold mixture. A mixture is prepared by adding an oxide source such as silica and/or alumina so that the molar ratio _{of R 2/f} O/(SiO ₂ +Al ₂ O ₃ ) is 0.01 to 2.0 to the primary template mixture. The prepared mixture is stirred at 20° C. to 40° C. for 5 minutes to 3 hours, and then stirred at 20° C. to 100° C. for 10 minutes to 24 hours or left without stirring. The stirred mixture may be crystallized at a temperature of 50° C. to 175° C. for 1 hour to 72 hours to prepare a porous metal oxide in which the pores are arranged in a hexagonal shape. Optionally, the porous metal oxide having the prepared pores arranged in a hexagonal shape may be dehydrated or calcined, and the firing may be performed at 540° C. for 1 hour, for example.

Meanwhile, the ion exchange membrane may include 0.01 parts by weight to 0.50 parts by weight of the porous metal oxide based on 1 part by weight of the ion conductor, and specifically 0.05 parts by weight to 0.25 parts by weight. When the content of the porous metal oxide is less than 0.01 parts by weight based on 1 part by weight of the ion conductor, it may be difficult to effectively prevent permeation of vanadium ions, and when it exceeds 0.50 parts by weight, aggregation in the ion exchange membrane or physical properties of the ion exchange membrane It can be degraded.

The porous metal oxide may be included in the ion exchange membrane in various forms. For example, the porous metal oxide may be mixed with the ion conductor and dispersed in the polymer membrane.

The polymer membrane in which the porous metal oxide is dispersed may be prepared by physically mixing the porous metal oxide with the ion conductor solution and then forming the ion conductor solution.

The ion conductor solution may be in the form of a dispersion, and the ion conductor solution or dispersion may be used by purchasing a commercially available ion conductor solution or dispersion, or may be prepared by dispersing the ion conductor in a solvent.

As a solvent for preparing the ion conductor solution or dispersion, a solvent selected from the group consisting of water, a hydrophilic solvent, an organic solvent, and one or more mixtures thereof may be used. The hydrophilic solvent is a group consisting of alcohols, isopropyl alcohols, ketones, aldehydes, carbonates, carboxylates, carboxylic acids, ethers, and amides containing linear, branched saturated or unsaturated hydrocarbons having 1 to 12 carbon atoms as the main chain. It may have one or more functional groups selected from, and these may include an alicyclic or aromatic cyclo compound as at least a part of the main chain. The organic solvent may be selected from N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, and mixtures thereof.

The method of forming the polymer film using the ion conductor solution may be performed by applying the ion conductor solution on a substrate and then drying it. The coating may use any one method selected from the group consisting of bar coating, comma coating, slot die, screen printing, spray coating, doctor blade, laminating, and combinations thereof. The drying may be drying at 60° C. to 150° C. for 0.5 to 12 hours.

As another example, the porous metal oxide may be included in the form of a coating layer on one or both surfaces of the polymer film. That is, the ion exchange membrane may include a polymer membrane including the ion conductor, and a coating layer disposed on one or both surfaces of the polymer membrane and including the porous metal oxide. In this case, the coating layer including the porous metal oxide may be 0.05 part by volume to 1.0 part by volume, and specifically, it may be 0.05 part by volume to 0.2 part by volume, based on 1 part by volume of the polymer film. When the coating layer is less than 0.05 part by volume with respect to 1 part by volume of the polymer film, the effect of preventing the penetration of vanadium ions may be reduced.

The ion exchange membrane may be prepared by forming the polymer membrane and then forming a coating layer thereon using a solution containing the porous metal oxide. The solution containing the porous metal oxide may be prepared by adding the porous metal oxide to a solvent, and the solvent may be water, a hydrophilic solvent, an organic solvent, and one of them, which are solvents that can be used to prepare the ion conductor solution. A solvent selected from the group consisting of the above mixtures may be used in the same manner. In addition, the method of forming the coating layer may be performed by applying a solution containing the porous metal oxide on the polymer film and then drying it. The method of applying the solution containing the porous metal oxide on the polymer film may be any one method selected from the group consisting of bar coating, comma coating, slot die, screen printing, spray coating, doctor blade, laminating, and combinations thereof. Can be used. The drying may be drying at 60° C. to 150° C. for 0.5 to 12 hours.

As another example, the ion exchange membrane may be in a form in which a first polymer membrane in which the porous metal oxide is not dispersed and a second polymer membrane in which the porous metal oxide is dispersed are stacked. That is, the ion exchange membrane may include a first polymer membrane including the ion conductor, and a second polymer membrane including the ion conductor and the porous metal oxide mixed and dispersed with the ion conductor. A plurality of the first polymer membranes and the second polymer membranes may be alternately stacked. In this case, the second polymer membrane may be from 0.05 part by volume to 1.0 part by volume, and specifically from 0.05 part by volume to 0.2 part by volume with respect to 1 part by volume of the first polymer membrane. When the second polymer film is less than 0.05 part by volume with respect to 1 part by volume of the first polymer film, the effect of preventing permeation of vanadium ions may be reduced.

The ion exchange membrane may be prepared by forming the first polymer membrane and the second polymer membrane, respectively, and then compressing the two polymer membranes, and a laminating method or the like may be applied when the plurality of polymer membranes are laminated.

1 is a diagram schematically showing the selective permeation of ions in an ion exchange membrane in which the first polymer membrane and the second polymer membrane are stacked.

Referring to FIG. 1, the ion exchange membrane 104 is mixed with a first polymer membrane 10 including a first ion conductor 11, a second ion conductor 21, and the second ion conductor 21 The second polymer film 20 including the dispersed porous metal oxide 22 is stacked. 1 shows a case in which the porous metal oxide 22 has a hexagonal column shape in which the pores are arranged in a hexagonal shape. The porous metal oxide 22 prevents the penetration of the vanadium ions by having micropores similar to the size (1.15 nm) of the vanadium _{pentavalent ions (VO 2} ^{+ ), while preventing the transmission of the proton (H +} ) or hydro By being larger than the size of nium ions (< 0.32 nm), ions can be selectively transmitted.

An energy storage device according to another embodiment of the present invention includes the ion exchange membrane. Hereinafter, a case where the energy storage device is a redox flow battery will be described in detail, but the present invention is not limited thereto, and the ion exchange membrane may be applied to an energy storage device in the form of a fuel cell or a secondary battery.

In one example of the energy storage device, the ion exchange membrane has low vanadium ion permeability by blocking vanadium ions due to a small ion channel, and when applied to a vanadium redox flow battery, the vanadium active material crossover. As a result, high energy efficiency can be achieved by solving the problem of lowering energy efficiency. The energy storage device may preferably be a redox flow battery.

The redox flow battery may perform charging and discharging by supplying a positive electrode electrolyte and a negative electrode electrolyte to a battery cell including a positive electrode and a negative electrode disposed to face each other, and the ion exchange membrane disposed between the positive electrode and the negative electrode.

The redox flow battery includes an all-vanadium-based redox battery using a V(IV)/V(V) redox couple as a positive electrolyte and a V(II)/V(III) redox couple as a negative electrolyte; A vanadium-based redox battery using a halogen redox couple as a positive electrode electrolyte and a V(II)/V(III) redox couple as a negative electrode electrolyte; A polysulfide bromine redox battery using a halogen redox couple as a positive electrolyte and a sulfide redox couple as a negative electrolyte; Alternatively, it may be a zinc-bromine (Zn-Br) redox battery using a halogen redox couple as a positive electrolyte and a zinc (Zn) redox couple as a negative electrolyte, but in the present invention, the type of the redox flow battery is Not limited.

Hereinafter, a case where the redox flow battery is an all-vanadium-based redox battery will be described as an example. However, the redox flow battery of the present invention is not limited to the all-vanadium-based redox battery.

2 is a schematic diagram schematically showing the all-vanadium-based redox battery.

Referring to FIG. 2, the redox flow battery includes a cell housing 102, the ion exchange membrane 104 installed to divide the cell housing 102 into a positive cell 102A and a negative cell 102B, and the It includes an anode 106 and a cathode 108 positioned in the anode cell 102A and the cathode cell 102B, respectively.

In addition, the redox flow battery may further include a positive electrolyte storage tank 110 in which the positive electrolyte is stored and a negative electrolyte storage tank 112 in which the negative electrolyte is stored.

In addition, the redox flow battery includes a cathode electrolyte inlet and a cathode electrolyte outlet at the top and bottom of the anode cell 102A, and a cathode electrolyte inlet and a cathode electrolyte outlet at the top and bottom of the cathode cell 102B. can do.

The positive electrolyte stored in the positive electrolyte storage tank 110 flows into the positive electrode cell 102A through the positive electrolyte inlet by the pump 114, and then from the positive electrode cell 102A through the positive electrolyte outlet. Is discharged.

Likewise, the negative electrolyte stored in the negative electrolyte storage tank 112 is introduced into the negative electrode cell 102B through the negative electrolyte inlet by the pump 116, and then the negative electrode cell 102B through the negative electrolyte outlet. ) Is discharged from.

In the anode cell 102A, movement of electrons through the anode 106 occurs according to the operation of the power/load 118, and accordingly, an oxidation/reduction reaction of ^{V 5+} ↔ ^{V 4+ occurs.} Likewise, in the cathode cell 102B, the movement of electrons through the cathode 108 occurs according to the operation of the power/load 118, and accordingly, an oxidation/reduction reaction of ^{V 2+} ↔ ^{V 3+ occurs.} After the oxidation/reduction reaction is completed, the positive electrolyte and the negative electrolyte are circulated to the positive electrolyte storage tank 110 and the negative electrolyte storage tank 112, respectively.

The anode 106 and the cathode 108 are Ru, Ti, Ir. A composite material containing oxides of at least one metal selected from Mn, Pd, Au, and Pt, and at least one metal selected from Ru, Ti, Ir, Mn, Pd, Au, and Pt (for example, on a Ti substrate Ir oxide or Ru oxide coated), a carbon composite comprising the composite material, a dimensionally stable electrode (DSE) comprising the composite material, a conductive polymer (e.g., a polymer that conducts electricity such as polyacetylene or polythiophene) Material), graphite, glassy carbon, conductive diamond, conductive DLC (Diamond-Like Carbon), nonwoven fabric made of carbon fiber, and woven fabric made of carbon fiber.

The positive and negative electrolytes may include any one metal ion selected from the group consisting of titanium ions, vanadium ions, chromium ions, zinc ions, tin ions, and mixtures thereof.

For example, the negative electrolyte includes vanadium divalent ions (V ²⁺ ) or vanadium trivalent ions (V ³⁺ ) as negative electrolyte ions, and the positive electrolyte is vanadium tetravalent ions (V ^{4) as positive electrolyte ions. +} ) Or vanadium ^pentavalent ion (V 5+) may be included.

It is preferable that the concentration of the metal ions contained in the positive and negative electrolytes is 0.3 M to 5 M.

As a solvent for the positive and negative electrolytes, H ₂ SO ₄ , K ₂ SO ₄ , Na ₂ SO ₄ , H ₃ PO ₄ , H ₄ P ₂ O ₇ , K ₂ PO ₄ , Na ₃ PO ₄ , K ₃ PO Any one selected from the group consisting of ₄ , HNO ₃ , KNO ₃ and NaNO _{3 may be used.} Since all of the metal ions used as the positive and negative active materials are water-soluble, an aqueous solution may be suitably used as a solvent for the positive and negative electrolytes. In particular, when any one selected from the group consisting of sulfuric acid, phosphoric acid, nitric acid, sulfate, phosphate and nitrate is used as the aqueous solution, the stability, reactivity, and solubility of the metal ion can be improved.

Meanwhile, the ion exchange membrane may also be applied to a membrane-electrode assembly for a fuel cell, and specifically, the membrane-electrode assembly includes an anode electrode and a cathode electrode positioned opposite to each other, and the above-described ions positioned between the anode electrode and the cathode electrode. It may include an exchange membrane.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[Production Example 1: Preparation of ion conductor]

(Production Example 1-1)

1) Preparation of hydrophobic repeating unit

DMAc in the presence of potassium carbonate (bisphenol A) and 1,3-bis (4-fluorobenzoyl) benzene (1,3-bis (4-fluorobenzoyol) benzene) as shown in Scheme 3 below. /Toluene was reacted for 30 hours between 160°C and 180°C using a co-solvent, discharged to purified water, washed, and then dried with hot air. At this time, carother's equation was used to control the degree of polymerization of the oligomer.

[Scheme 3]

2) Preparation of hydrophilic repeating unit

As shown in Scheme 4 below, 4,4'-(9-fluorenylidene)diphenol (4,4'-(9-fluorenyliene)diphenol) and bis(4-fluorophenyl)sulfone (bis(4-fluorophenyl) )sulfone) was reacted for 30 hours between 160° C. and 180° C. using a DMAc/Toluene co-solvent in the presence of Potassium carbonate, then discharged to purified water, washed, and then dried with hot air. At this time, carother's equation was used to control the degree of polymerization of the oligomer.

[Scheme 4]

3) Preparation of polymer

The prepared hydrophobic repeating unit and hydrophilic repeating unit were reacted for 30 hours between 160° C. and 180° C. using a DMAc/Toluene co-solvent in the presence of potassium carbonate, then discharged to purified water, washed, and then dried with hot air. I did. The hydrophilic repeating unit of the prepared polymer: the molar ratio of the hydrophobic repeating unit was 1:3.5.

4) Preparation of ion conductor

After dissolving the prepared polymer in dichloromethane, it was slowly added to a 5-fold excess of chlorosulfonic acid/DCM solution and stirred for 24 hours. The solution was discarded, the precipitated solid was washed with purified water, and then dried with hot air.

(Production Example 1-2)

In Preparation Example 1-1, an ion conductor was prepared in the same manner as in Preparation Example 1-1, except that the polymer was prepared so that the molar ratio of the hydrophilic repeating unit: the hydrophobic repeating unit was 1:2.5. I did.

(Production Example 1-3)

1) Preparation of hydrophobic repeating unit

4,4'-dihydroxybenzophenone (4,4'-dihydroxybenzophenone) and 2,6-difluorobenzonitrile in the presence of potassium carbonate as shown in Scheme 5 below. Then, it was reacted for 30 hours between 160° C. and 180° C. using a DMAc/Toluene co-solvent under, and then discharged to purified water, washed, and then dried with hot air. At this time, carother's equation was used to control the degree of polymerization of the oligomer.

[Scheme 5]

2) Preparation of hydrophilic repeating unit

As shown in Scheme 6 below, 4,4'-(9-fluorenylidene)diphenol (4,4'-(9-fluorenyliene)diphenol) and bis(4-fluorophenyl)sulfone (bis(4-fluorophenyl) )sulfone) was reacted for 30 hours between 160° C. and 180° C. using a DMAc/Toluene co-solvent in the presence of Potassium carbonate, then discharged to purified water, washed, and then dried with hot air. At this time, carother's equation was used to control the degree of polymerization of the oligomer.

[Scheme 6]

3) Preparation of polymer

The prepared hydrophobic repeating unit and hydrophilic repeating unit are reacted for 30 hours at 160° C. to 180° C. using a DMAc/Toluene co-solvent in the presence of potassium carbonate, then discharged to purified water, washed, and then dried with hot air. I did. The molar ratio of the hydrophilic repeating unit (Y) to the hydrophobic repeating unit (X) of the prepared polymer was 1:3.5.

4) Preparation of ion conductor

After dissolving the prepared polymer in dichloromethane, it was slowly added to a 5-fold excess of chlorosulfonic acid/DCM solution and stirred for 24 hours. The solution was discarded, the precipitated solid was washed with purified water, and then dried with hot air.

(Production Example 1-4)

In Preparation Example 1-3, when the polymer was prepared, an ion conductor was prepared in the same manner as in Preparation Example 1-3, except that the polymer was prepared so that the molar ratio of the hydrophilic repeat unit: the hydrophobic repeat unit was 1: 2.5. I did.

(Production Example 1-5)

1) Preparation of hydrophobic repeating unit

4,4'-dihydroxybenzophenone (4,4'-dihydroxybenzophenone) and bis (4-fluorophenyl) sulfone (bis (4-fluorophenyl) sulfone) in the presence of potassium carbonate (Potassium carbonate) DMAc / Toluene After reacting for 30 hours between 160° C. and 180° C. using a co-solvent, it was discharged into purified water, washed, and then dried with hot air. At this time, carother's equation was used to control the degree of polymerization of the oligomer.

2) Preparation of hydrophilic repeating unit

4,4'-(9-fluorenylidene)diphenol (4,4'-(9-fluorenyliene)diphenol) and 1,3-bis(4-fluorobenzoyl)benzene (1,3-bis(4 -fluorobenzoyol)benzene) was reacted with a DMAc/Toluene co-solvent for 30 hours in the presence of potassium carbonate (Potassium carbonate) between 160° C. and 180° C., discharged to purified water, washed, and then dried with hot air. At this time, carother's equation was used to control the degree of polymerization of the oligomer.

3) Preparation of polymer

The prepared hydrophobic repeating unit and hydrophilic repeating unit were reacted for 30 hours between 160° C. and 180° C. using a DMAc/Toluene co-solvent in the presence of potassium carbonate, then discharged to purified water, washed, and then dried with hot air. Thus, a polymer represented by the following formula (8) was prepared. The molar ratio of the hydrophilic repeating unit (X) to the hydrophobic repeating unit (Y) of the prepared polymer was 1:3.5.

[Formula 8]

4) Preparation of ion conductor

After dissolving the prepared polymer in dichloromethane, it was slowly added to a 5-fold excess of chlorosulfonic acid/DCM solution and stirred for 24 hours. The solution was discarded, the precipitated solid was washed with purified water, and then dried with hot air.

(Production Example 1-6)

In Preparation Example 1-5, an ion conductor was prepared in the same manner as in Preparation Example 1-5, except that the polymer was prepared so that the molar ratio of the hydrophilic repeating unit: the hydrophobic repeating unit was 1:2.5. I did.

[Production Example 2: Preparation of porous support]

(Production Example 2-1)

Polyamic acid was dissolved in dimethylformamide to prepare 5 L of a spinning solution of 480 poise. After transferring the prepared spinning solution to a solution tank, it was supplied to a spinning chamber composed of 20 nozzles and applied at a high voltage of 3 kV through a quantitative gear pump, and spun to prepare a web of nanofiber precursors. At this time, the amount of solution supplied was 1.5 ml/min. The prepared web of the nanofiber precursor was heat-treated at 350° C. to prepare a porous support (porosity: 40% by volume).

The weight per unit area of the polyimide nanofibers in the porous support was 6.8 gsm.

[Production Example 3: Preparation of Porous Metal Oxide]

(Production Example 3-1)

100 g of cetyl trimethyl ammonium (CTMA) hydroxide solution and 100 g of tetramethyl ammonium (TMA) silicate solution (10% by weight silica) were mixed while stirring. 25 g of HiSil, a precipitated hydrated silica having a particle size of 0.02 μm, was added to the mixture. The silica-added mixture was placed in a polypropylene bottle and crystallized overnight in a vapor box at 95°C.

The resulting solid product was recovered by filtration and dried in air at ambient temperature. The product was then calcined at 540° C. for 1 hour in nitrogen and then in air for 6 hours.

The calcined product had a surface area of 475 m ² /g and a benzene adsorption capacity (@ 50 torr, 25° C.) of 21.5 g/100 g.

In addition, as a result of measuring the X-ray diffraction pattern of the product, 10 Å units d-spacing was 8.842 degrees 2-theta (Cu K-alpha radiation), and 18 Å units d-spacing was 4.909 degrees 2-theta (Cu K-alpha radiation). The product showed very strong peaks at 37.8±2.0 Å d-spacing, and weak peaks at 21.6±1.0 and 19.2±1.0 Å d-spacing.

In addition, the product produced an image of a hexagonal electron diffraction pattern having uniform pores arranged in a hexagonal shape in a transmission electron microscope (TEM) image and having a d _{100 value of about 39 Å.}

The pore size of the prepared porous metal oxide was 1 nm, the height was 20 nm, and the aspect ratio was 1:1.

[Example 1: Preparation of single membrane type ion exchange membrane]

(Examples 1-1 to 1-6)

0.2 parts by weight of the ion conductor prepared in Preparation Examples 1-1 to 1-6 and 0.04 parts by weight of the porous metal oxide prepared in Preparation Example 3-1 were dissolved in 1 part by weight of DMAc, respectively, and formed into a single film. An ion exchange membrane was prepared.

The prepared ion exchange membrane contained 0.2 parts by weight of the porous metal oxide based on 1 part by weight of the ion conductor.

(Comparative Examples 1-1 to 1-6)

After dissolving 0.2 parts by weight of the ion conductors prepared in Preparation Examples 1-1 to 1-6, respectively, in 1 part by weight of DMAc, the film was formed to prepare an ion exchange membrane in the form of a single membrane.

[Example 2: Preparation of an ion exchange membrane in the form of a coating layer]

(Examples 2-1 to 2-6)

After dissolving 0.2 parts by weight of the ion conductors prepared in Preparation Examples 1-1 to 1-6, respectively, in 1 part by weight of DMAc, the film was formed to prepare a polymer film in the form of a single film.

0.2 parts by weight of the porous metal oxide prepared in Preparation Example 3-1 was dissolved in 1 part by weight of DMAc to prepare a solution containing the porous metal oxide. The solution containing the porous metal oxide was first applied to one side of the polymer membrane, dried at 90° C. for 1 hour, applied secondly on the first drying, and dried at 90° C. for 1 hour to form a coating layer. Formed.

The prepared ion exchange membrane contained 0.04 parts by weight of the porous metal oxide based on 1 part by weight of the ion conductor, and the coating layer including the porous metal oxide was 0.2 parts by volume based on 1 part by volume of the polymer membrane.

(Example 2-7)

After dissolving 0.2 parts by weight of the ion conductor prepared in Preparation Example 1-1 in 1 part by weight of DMAc, the film was formed to prepare a polymer film in the form of a single film.

Using the same method as in Preparation Example 3-1, but dissolving 0.04 parts by weight of a porous metal oxide prepared so that the pore size is 2 nm in 1 part by weight of DMAc, a solution containing the porous metal oxide was prepared. The solution containing the porous metal oxide was first applied to one side of the polymer membrane, dried at 90° C. for 1 hour, applied secondly on the first drying, and dried at 90° C. for 1 hour to form a coating layer. Formed.

The prepared ion exchange membrane contained 0.04 parts by weight of the porous metal oxide based on 1 part by weight of the ion conductor, and the coating layer including the porous metal oxide was 0.2 parts by volume based on 1 part by volume of the polymer membrane.

(Comparative Examples 2-1 to 2-6)

After dissolving 0.2 parts by weight of the ion conductors prepared in Preparation Examples 1-1 to 1-6, respectively, in 1 part by weight of DMAc, the film was formed to prepare a polymer film in the form of a single film.

A solution containing a porous metal oxide was prepared by dissolving 0.04 parts by weight of silica (manufacturer: ACS Materials, product name: MCM-48) having a 3D cubic shape and a pore size of 1 nm in 1 part by weight of DMAc. The solution containing the porous metal oxide was first applied to one side of the polymer membrane, dried at 90° C. for 1 hour, applied secondly on the first drying, and dried at 90° C. for 1 hour to form a coating layer. Formed.

The prepared ion exchange membrane contained 0.04 parts by weight of silica based on 1 part by weight of the ion conductor, and the coating layer including the porous metal oxide was 0.2 parts by volume based on 1 part by volume of the polymer membrane.

[Example 3: Preparation of an ion exchange membrane in the form of a laminated membrane]

(Examples 3-1 to 3-6)

After dissolving 0.2 parts by weight of the ion conductors prepared in Preparation Examples 1-1 to 1-6, respectively, in 1 part by weight of DMAc, the film was formed to prepare a first polymer film having a thickness of 40 μm.

0.2 parts by weight of the ion conductor prepared in Preparation Examples 1-1 to 1-6 and 0.04 parts by weight of the porous metal oxide prepared in Preparation Example 3-1 were dissolved in 1 part by weight of DMAc, respectively, and then formed to have a thickness of 10. A second polymer membrane of µm was prepared.

The first polymer membrane and the second polymer membrane were stacked and then thermally compressed at 150° C. and 1500 MPa to prepare an ion exchange membrane.

The prepared ion exchange membrane contained 0.04 parts by weight of the porous metal oxide based on 1 part by weight of the ion conductor, and the second polymer membrane was 0.2 parts by volume based on 1 part by weight of the first polymer membrane.

[Example 4: Preparation of an ion exchange membrane in the form of a reinforced membrane]

(Examples 4-1 to 4-6)

An ion conductor solution was prepared by dissolving 0.2 parts by weight of the ion conductor prepared in Preparation Examples 1-1 to 1-6 and 0.04 parts by weight of the porous metal oxide prepared in Preparation Example 3-1, respectively, in 1 part by weight of DMAc. .

Next, the porous support prepared in Preparation Example 2-1 was impregnated in the ion conductor solution twice for 30 minutes, left to stand under reduced pressure for 1 hour, and dried for 10 hours at 80° C. An exchange membrane was prepared.

The prepared ion exchange membrane contained 0.2 parts by weight of the porous metal oxide based on 1 part by weight of the ion conductor.

(Comparative Examples 4-1 to 4-6)

An ion conductor solution was prepared by dissolving 0.2 parts by weight of the ion conductors prepared in Preparation Examples 1-1 to 1-6, respectively, in 1 part by weight of DMAc.

Next, the porous support prepared in Preparation Example 2-1 was impregnated in the ion conductor solution twice for 30 minutes, left to stand under reduced pressure for 1 hour, and dried for 10 hours at 80° C. An exchange membrane was prepared.

[Experimental Example 1: Analysis of vanadium permeability of the prepared ion exchange membrane]

Vanadium permeability was measured for the ion exchange membranes prepared in Examples 1-1 to 4-6 and Comparative Examples 1-1 to 4-6, and the results are shown in Table 1 below.

The vanadium permeability was _{measured by UV-vis spectroscopy by placing a membrane between the MgSO 4} solution and the vanadium solution, and the amount of vanadium ions transmitted over time.

Vanadium transmittance (cm ² /min) Example 1-1 1.57×10 ^-7 Example 2-1 2.26×10 ^-8 Example 2-7 9.78×10 ^-8 Example 3-1 2.40×10 ^-8 Comparative Example 1-1 9.71×10 ^-7 Comparative Example 2-1 6.32×10 ^-8 Example 4-1 6.78×10 ^-9 Comparative Example 4-1 1.03×10 ^-8 Nafion212
Commercial film 2.48×10 ^-6

Referring to Table 1, in the case of the ion exchange membrane prepared in the above examples, it was confirmed that the penetration of vanadium pentavalent ions was prevented by including the porous metal oxide compared to the ion exchange membrane prepared in the comparative examples. I can.

[Experimental Example 2: Performance Analysis of the Prepared Ion Exchange Membrane]

Voltage efficiency, current efficiency, and system efficiency were measured for the ion exchange membranes prepared in Examples 1-1 to 4-6 and Comparative Examples 1-1 to 4-6, and the results are shown in Table 2 below. Indicated.

The system efficiency (EE, Energy Efficiency) of the ion exchange membrane was measured by configuring the following apparatus to measure electrochemical properties.

The device for measuring the energy efficiency consisted ^{of a unit cell having an electrode area of 25 cm 2} , two aqueous solution tanks, and a pump for measuring electrochemical properties in VRFB. A solution containing 30 mL of 1.7 M VOSO ₄ and 2.5 MH ₂ SO ₄ (a solution of tetravalent vanadium) was used as the anolyte, and an aqueous solution obtained by electrolytic reduction of the anolyte (aqueous solution of trivalent vanadium) was used as the catholyte. The anolyte was used in an amount slightly larger than that of the catholyte to suppress overcharging. The unit cell for measurement consisted of a film to be measured, a heat treated carbon felt (made by Nippon Carbon, Inc.) having a size of ^{25 cm 2, and a current collector.} For charging/discharging the unit cell for measurement, a static potential/constant current device was used, and the charging/discharging current density was measured at ^{60 mA/cm 2.} In addition, charging/discharging of the unit cell was set to 1.6 V for charging and 1.0 V for discharging and proceeded in a cur-off method, and charging/discharging was performed 5 times, and current efficiency (CE) and voltage efficiency were used by using Equation 2 below. (VE) and energy efficiency (EE) were calculated.

[Equation 2]

CE=Q _D /Q _C

VE=E _AD /E _AC

EE=CE×VE

Here, Q _C [C] and Q _D [C] are coulomb amounts during charging and discharging, and E _AC [V] and E _AD [V] are cell voltages during charging and discharging.

Film thickness(㎛) Voltage efficiency
(VE) Current efficiency
(CE) System efficiency
(EE) Example 1-1 55 92% 94% 86% Example 2-1 55 91% 94% 86% Example 2-7 55 92% 93% 86% Example 3-1 55 92% 94% 86% Comparative Example 1-1 55 89% 94% 84% Comparative Example 2-1 55 90% 94% 85% Example 4-1 55 91% 93% 85% Comparative Example 4-1 55 89% 94% 84% Nafion212
Commercial film 25 87% 94% 82%

Referring to Table 2, in the case of the ion exchange membrane prepared in the Examples, as compared to the ion exchange membrane prepared in Comparative Examples, the penetration of vanadium pentavalent ions was prevented, as compared to the ion exchange membrane prepared in Comparative Examples. It can be seen that the efficiency is improved and deterioration is prevented.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also present. It belongs to the scope of rights of

104: ion exchange membrane
10: first polymer membrane
11: first ion conductor
20: second polymer membrane
21: second ion conductor
22: porous metal oxide
102: cell housing
102A: anode cell 102B: cathode cell
104: ion exchange membrane
106: anode
108: cathode
110: anode electrolyte storage tank
112: cathode electrolyte storage tank
114, 116: pump
118: power/load

Claims (16)

A polymeric membrane containing an ionic conductor, and
Porous metal oxide having a pillar shape, extending along the height direction of the pillar and including a plurality of pores penetrating the pillar
Including,
The pore size of the porous metal oxide is 0.35 nm to 1.2 nm,
Ion exchange membrane. The method of claim 1,
The size of the pores of the porous metal oxide is 0.5 nm to 1 nm of the ion exchange membrane. The method of claim 1,
The columnar porous metal oxide is an ion exchange membrane having a height of 3 nm to 200 nm. The method of claim 1,
The pillar-shaped porous metal oxide has an aspect ratio of 1: 0.1 to 1: 1. The ion exchange membrane. The method of claim 1,
The porous metal oxide is any one selected from the group consisting of silica, organic silica, metal oxide other than silica, and metal oxide other than silica-silica composite. The method of claim 1,
The porous metal oxide is an ion exchange membrane having a hexagonal column shape, wherein the plurality of pores are arranged in a hexagonal shape in a cross section in a direction perpendicular to the height direction of the column. The method of claim 6,
The hexagonal columnar porous metal oxide has a _{hexagonal electron diffraction pattern having a d 100} value of 18 Å or more,
An ion exchange membrane having a benzene adsorption capacity (@ 50 torr, 25 ℃) of 15 g/100 g (grams of benzene/grams of porous metal oxide) or more. The method of claim 1,
The ion exchange membrane is an ion exchange membrane containing the porous metal oxide in an amount of 0.01 parts by weight to 0.50 parts by weight based on 1 part by weight of the ion conductor. The method of claim 1,
The porous metal oxide is mixed with the ion conductor and dispersed in the polymer membrane. The method of claim 1,
The ion exchange membrane
A polymer membrane comprising the ion conductor, and
It is positioned on the surface of one or both surfaces of the polymer membrane, the ion exchange membrane comprising a coating layer containing the porous metal oxide. The method of claim 10,
The coating layer including the porous metal oxide is an ion exchange membrane in which 0.05 parts by volume to 1.0 parts by volume per 1 part by volume of the polymer membrane. The method of claim 1,
The ion exchange membrane
A first polymer membrane comprising the ion conductor,
The ion conductor and the second polymer membrane including the porous metal oxide dispersed by being mixed with the ion conductor is stacked
Ion exchange membrane. The method of claim 12,
The second polymer membrane is an ion exchange membrane in which 0.05 part by volume to 1.0 part by volume with respect to 1 part by volume of the first polymer membrane. The method of claim 1,
The polymer membrane is
A porous support comprising a plurality of pores, and
The ion conductor filling the pores of the porous support
The ion exchange membrane comprising a. An energy storage device comprising the ion exchange membrane according to claim 1. The method of claim 15,
The energy storage device is an energy storage device that is a redox flow battery.

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