KR101860541B1 - Method for producing crosslinked polymer electrolyte composite membranes, the composite membranes produced thereby and energy storage device comprising the composite membranes - Google Patents

Abstract

The present invention relates to a crosslinked polymer composite membrane and a method for producing the same, and more particularly, to a crosslinked polymer composite membrane having an improved strength and durability with mutual bonding properties through ionic crosslinking between a cation conductive polymer and an anionic conductive polymer, A composite membrane produced by the method, and an energy storage device comprising the composite membrane. [0002] The present invention relates to a composite membrane,

Description

FIELD OF THE INVENTION [0001] The present invention relates to a crosslinked polymer electrolyte composite membrane, a composite membrane prepared by the method, and an energy storage device comprising the composite membrane,

The present invention relates to a crosslinked polymer composite membrane and a method for producing the same, and more particularly, to a crosslinked polymer composite membrane having an improved strength and durability with mutual bonding properties through ionic crosslinking between a cation conductive polymer and an anionic conductive polymer, A composite membrane produced by the method, and an energy storage device comprising the composite membrane. [0002] The present invention relates to a composite membrane,

In recent years, development of a high performance fuel cell having high energy efficiency, operation at room temperature, and reliability has been urgently required along with exhaustion of environmental problems and energy sources, commercialization of fuel cell vehicle, and so on. Accordingly, development of a polymer electrolyte membrane capable of increasing the efficiency of a fuel cell is also required.

Currently used polymer electrolyte membranes are mainly composed of Nafion (a trade name of DuPont), Flemion (a trade name of Asahi Glass), Asiplex (trade name of Asahi Chemical), and Dow XUS , A perfluorosulfonate ionomer membrane such as an electrolyte membrane manufactured by Dow Chemical Co., Ltd.) is widely used, but it is a considerable burden in commercialization of the polymer electrolyte membrane because its cost is considerably high .

In order to solve these burdens, a hydrocarbon-based polymer such as polyether ether ketone, polysulfone, and polyimide, which is relatively inexpensive and has various commercial applications, Is being actively researched. The polymer is prepared by ion-conducting polymer by sulphonation reaction and then cast into an electrolyte membrane, which is applied as a fuel cell electrolyte membrane

In order to improve the oxidation resistance and thermal / mechanical stability, which are the biggest disadvantages of the above hydrocarbon-based polymers, and to improve the low bonding property with the electrode due to excessive swelling during the production of the membrane electrode assembly (MEA) A method of fabricating a composite membrane by impregnating pores of a perfluorocompound or a hydrocarbon-based polymer on a porous support having excellent mechanical, thermal, and oxidation resistance has been proposed. A commercially available example is W.L. Gore & Associates' Gore-select exhibits excellent mechanical and electrochemical properties with a thickness of 20 to 40 μm.

In order to produce the composite membrane as described above, styrene which is a hydrocarbon monomer instead of Nafion is impregnated with various polyvinyl supports such as Teflon, polyethylene (PE) and polyvinylidene difluoride (PVDF) together with a divinylbenzene crosslinking agent, And a method of producing an electrolyte membrane by impregnating a porous support with an acrylic sulfonic acid monomer and a water soluble crosslinking agent as described above and crosslinking the electrolyte membrane.

The styrene-divinylbenzene crosslinked electrolyte membrane is disadvantageous in that it becomes brittle with an increase in brittleness when it is in a dry state, resulting in mass production in the form of a thin film or a composite membrane and mechanical stability in processing into an electrode. In addition, since the acryl sulfonic acid crosslinked electrolyte pore filling membrane has poor durability, it is known that the hydrocarbon-based polymer membrane can not be widely commercialized due to such drawbacks.

As a result of efforts to solve the above problems, the present inventors have found that a crosslinked polymer electrolyte composite membrane having improved strength and durability can be produced at a high synthesis yield while greatly reducing the synthesis process, Completed.

Accordingly, it is an object of the present invention to provide a polymer electrolyte membrane which can exhibit a strength and durability that is 50% or more higher than that of a conventional polymer electrolyte membrane through a structure having mutual binding characteristics due to ionic crosslinking between the cation conductive polymer and the anionic conductive polymer, And to provide a crosslinked polymer electrolyte composite membrane capable of realizing excellent dimensional stability and high mechanical strength of 40 MPa or more even in a contacting condition.

Another object of the present invention is to provide a method for preparing a polymer electrolyte membrane which can dissolve a cation conductive polymer and an anionic conductive polymer to form an ionic crosslinking structure in a polymer state instead of a monomer, And a method for producing a polymer electrolyte composite membrane.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to accomplish the objects of the present invention described above, the present invention provides a method for preparing a cationic conductive polymer solution, comprising: preparing a cationic conductive polymer solution by dissolving the cationic conductive polymer in a solvent; Preparing an anionic conductive polymer solution by dissolving an anionic conductive polymer in a solvent; And a crosslinking step of mixing and crosslinking the cationic conductive polymer solution, the anion conductive polymer solution and the crosslinking agent to form a solution precursor solution.

In a preferred embodiment, the cationic conducting polymer is selected from the group consisting of sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone S-PEEK), sulfonated polybenzimidazole (S-PBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS) Sulfonated polyphosphazene, and combinations thereof.

In a preferred embodiment, the anionically conductive polymer is selected from the group consisting of Im-bPPO, Chloromethylated bPPO, poly (1-allyl-3-methylimidazolium chloride and methyl methacrylate), ETFE-g-PDMAEMA (ethylene-tetrafluoroethylene-dimethylaminoethyl methacrylate) , chloromethylated / quaternized poly (phthalazinone ether ketone), ethylene-tetrafluoroethylene-dimethylamino ethyl methacrylate (DMAEMA), quaternary ammonium functionalized PAES, quaternary benzyl trimethylammonium and quaternized poly (phthalazinone ether sulfone ketone) Or more.

In a preferred embodiment, the solvent is an alcoholic solvent comprising methanol, ethanol, propanol, isopropanol, butanol, isobutanol; Ether-based solvents including diethyl ether, dipropyl ether, dibutyl ether, butyl ethyl ether, and tetrahydrofuran; Alcohol ether solvents including ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; Ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; An amide-based solvent including N-methyl-2-pyrrolidinone, 2-pyrrolidinone, N-methylformamide and N, N-dimethylformamide; A sulfoxide-based solvent containing dimethylsulfoxide and diethylsulfoxide; Diethylsulfone, and tetramethylene sulfone; Nitrile solvents including acetonitrile, benzonitrile; Amine-based solvents including alkylamines, cyclic amines, and aromatic amines; Ester solvents including methyl butyrate, ethyl butyrate and propyl propionate; A carboxylic acid ester-based solvent containing ethyl acetate and butyl acetate; Aromatic hydrocarbon solvents including benzene, ethylbenzene, chlorobenzene, toluene and xylene; An aliphatic hydrocarbon-based solvent including hexane, heptane, and cyclohexane; Halogenated hydrocarbon-based solvents including chloroform, tetrachlorethylene, carbon tetrachloride, dichloromethane, and dichloroethane; Propylene carbonate, ethylene carbonate, dimethyl carbonate, dibutyl carbonate, ethyl methyl carbonate, dibutyl carbonate, nitromethane, and nitrobenzene.

In a preferred embodiment, the crosslinking agent used in the crosslinking step is selected from the group consisting of dichloro xylene, xylylenediamine, o-xylylenediamine dihydrochloride, xylylenediamine / acrylonitrile adduct, 2,3,5,6-tetramethyl-1,4-xylylenediamine dihydrochloride, -dimethyl-1,4-xylylenediamine dihydrochloride.

In a preferred embodiment, the crosslinking step is carried out by mixing the cationic conductive polymer solution, the anionic conductive polymer solution, and the crosslinking agent, followed by stirring at 35 to 45 ° C.

In a preferred embodiment, the method further comprises a film-forming step of producing a crosslinked polymer composite membrane with the film-forming precursor solution formed in the crosslinking step.

In a preferred embodiment, the film-forming step includes casting the film-forming precursor solution on a flat plate to form a precursor film; A drying step of drying the cast precursor film to remove the solvent and the cross-linking agent contained in the precursor film; And immersing the dried precursor film in a basic aqueous solution.

The present invention also relates to a polymer electrolyte fuel cell comprising a cationically conductive polymer, an anionic conductive polymer, and a unit bonding unit comprising at least one ionic crosslinking formed between the cationic conductive polymer and the anionic conductive polymer; And a plurality of ionic crosslinks formed between the unit coupling units.

In a preferred embodiment, the cationic conducting polymer is selected from the group consisting of sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone S-PEEK), sulfonated polybenzimidazole (S-PBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS) Sulfonated polyphosphazene, and combinations thereof.

In a preferred embodiment, the anionically conductive polymer is selected from the group consisting of Im-bPPO, Chloromethylated bPPO, poly (1-allyl-3-methylimidazolium chloride and methyl methacrylate), ETFE-g-PDMAEMA (ethylene-tetrafluoroethylene-dimethylaminoethyl methacrylate) , chloromethylated / quaternized poly (phthalazinone ether ketone), ethylene-tetrafluoroethylene-dimethyl aminoethyl methacrylate (DMAEMA), quaternary ammonium functionalized PAES, quaternary benzyl trimethylammonium, quaternized poly (phthalazinone ether sulfone ketone) Or more.

In a preferred embodiment, the VO ²⁺ ion permeability is 4.0 ㅧ 10 ^-9 ㎠ / min or less.

In a preferred embodiment, it has a mechanical strength of at least 40 MPa.

The present invention also provides an energy storage device comprising a crosslinked polymer electrolyte composite membrane produced by any one of the above-described production methods or any one of the crosslinked polymer electrolyte composite membranes described above.

In a preferred embodiment, the energy storage device is a redox flow cell or a fuel cell.

The present invention has the following excellent effects.

First, the crosslinked polymer electrolyte composite membrane of the present invention can exhibit strength and durability that is 50% or more higher than that of the conventional polymer electrolyte membrane through a structure having mutual bonding properties due to ionic crosslinking between the cation conductive polymer and the anionic conductive polymer, It is possible to realize excellent dimensional stability and high mechanical strength of 40 MPa or more even under direct contact with water.

In addition, according to the method for producing a crosslinked polymer electrolyte composite membrane of the present invention, by dissolving a cationic conductive polymer and an anionic conductive polymer, ion bridging in a polymer state rather than a monomer is achieved, a synthesis process can be greatly reduced and a high synthesis yield can be obtained The manufacturing cost can be reduced.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

FIG. 1 is a view showing a part of a unit bonding unit constituting a crosslinked polymer electrolyte composite membrane according to an embodiment of the present invention.
2 is a graph showing the results of measurement of ionic conductivity of a crosslinked polymer electrolyte composite membrane according to an embodiment of the present invention.
3 is a graph showing the results of measuring the tensile strength of a crosslinked polymer electrolyte composite membrane according to an embodiment of the present invention.
4 is a schematic view of a vanadium redox flow cell including a crosslinked polymer electrolyte composite membrane according to another embodiment of the present invention.
FIG. 5 is a graph showing a result of measuring the permeability of vanadium ions measured in FIG.
FIG. 6 is a graph showing a result of measuring the Coulombic efficiency in FIG.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprising" or "having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless expressly defined in the present invention, are to be interpreted as an ideal or overly formal sense Do not.

Hereinafter, the technical structure of the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Like reference numerals used to describe the present invention throughout the specification denote like elements.

The technical feature of the present invention is that a method of dissolving a cationic conductive polymer and an anionic conductive polymer in a polymer state instead of a monomer to form an ionically crosslinked polymer can be manufactured at a high synthesis yield with a greatly reduced synthesis process, Method and a structure having a mutual bonding property due to the ionic crosslinking of the cationic conductive polymer and the anionic conductive polymer can exhibit a strength and durability that is 50% or more higher than that of the conventional polymer electrolyte membrane and excellent Dimensional stability and high mechanical strength of 40 MPa or more.

Accordingly, the method for preparing a composite polymer electrolyte membrane of the present invention comprises: preparing a solution of a cationic conductive polymer by dissolving the cationic conductive polymer in a solvent; Preparing an anionic conductive polymer solution by dissolving an anionic conductive polymer in a solvent; And a cross-linking step of mixing the cation-conductive polymer solution, the anion-conducting polymer solution and the cross-linking agent and crosslinking them to form a film-forming precursor solution. At this time, the solvent used for dissolving the cationic conductive polymer and the anionic conductive polymer may be the same or at least the same kind of solvent having similar physical and chemical properties for smooth crosslinking reaction in the crosslinking step.

In the present invention, the cationic conductive polymer may be any known cationic conductive polymer. However, in one embodiment, the cationic conductive polymer may be a sulfonated hydrocarbon-based polymer, particularly sulfonated polyimide (S-PI), sulfonated polyarylether sulfone polyaryl ether sulfone (S-PAES), sulfonated polyetheretherketone (S-PEEK), sulfonated polybenzimidazole (S-PBI), sulfonated polysulfone A sulfonated polystyrene (S-PS), a sulfonated polyphosphazene, and a combination thereof.

As an anionic conductive polymer, any known anion conductive polymer may be used. However, in one embodiment, the anionic conductive polymer may be an im-bPPO, a chloromethylated bPPO, a poly (1-allyl-3-methylimidazolium chloride and methyl methacrylate), an ethylene- (dimethylaminoethyl methacrylate), cardo-polyetherketone, chloromethylated / quaternized poly (phthalazinone ether ketone), ethylene-tetrafluoroethylene-dimethylaminoethyl methacrylate (DMAEMA), quaternary ammonium functionalized PAES, quaternary benzyl trimethylammonium and quaternized poly It may be any one or more selected from the group.

As the solvent for dissolving the cationic conductive polymer and the anionic conductive polymer, any known solvent may be used as long as it can simultaneously dissolve the cationic conductive polymer and the anionic conductive polymer. In one embodiment, the alcohol-based solvent includes methanol, ethanol, propanol, isopropanol, butanol, and isobutanol; Ether-based solvents including diethyl ether, dipropyl ether, dibutyl ether, butyl ethyl ether, and tetrahydrofuran; Alcohol ether solvents including ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; Ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; An amide-based solvent including N-methyl-2-pyrrolidinone, 2-pyrrolidinone, N-methylformamide and N, N-dimethylformamide; A sulfoxide-based solvent containing dimethylsulfoxide and diethylsulfoxide; Diethylsulfone, and tetramethylene sulfone; Nitrile solvents including acetonitrile, benzonitrile; Amine-based solvents including alkylamines, cyclic amines, and aromatic amines; Ester solvents including methyl butyrate, ethyl butyrate and propyl propionate; A carboxylic acid ester-based solvent containing ethyl acetate and butyl acetate; Aromatic hydrocarbon solvents including benzene, ethylbenzene, chlorobenzene, toluene and xylene; An aliphatic hydrocarbon-based solvent including hexane, heptane, and cyclohexane; Halogenated hydrocarbon-based solvents including chloroform, tetrachlorethylene, carbon tetrachloride, dichloromethane, and dichloroethane; Propylene carbonate, ethylene carbonate, dimethyl carbonate, dibutyl carbonate, ethyl methyl carbonate, dibutyl carbonate, nitromethane, and nitrobenzene.

The step of preparing the cation conductive polymer solution and the solution of the anionic conductive polymer may be carried out in any order. The cation conductive polymer and the anionic conductive polymer obtained by the purchase or direct preparation are completely dissolved in the same solvent, Prepare the conductive polymer solution separately. Here, the mixing ratio of the solvent and the cationic conductive polymer or the anionic conductive polymer may be 5 to 30 parts by weight based on 100 parts by weight of the solvent. The blending ratio was experimentally determined. When the weight of the polymer was less than 5 parts by weight or more than 30 parts by weight, the crosslinked polymer electrolyte membrane was not formed well in the film forming step.

The crosslinking step may be carried out by mixing the prepared cation conductive polymer solution, the anion conductive polymer solution, and the crosslinking agent in a single reactor and mixing and stirring at 35 to 45 ° C for several hours to several tens of hours. Any known cross-linking agent can be used as long as it can form a cross-link between the cation-conducting polymer and the anion-conducting polymer. One embodiment comprises dichloro xylene, xylylenediamine, o-xylylenediamine dihydrochloride, xylylenediamine / acrylonitrile adduct, 2,3,5,6-tetramethyl-1,4-xylylenediamine dihydrochloride, 2,5-dimethyl-1,4-xylylenediamine dihydrochloride May be any one or more selected from the group.

Meanwhile, the method for producing a crosslinked polymer composite membrane of the present invention may further include a membrane formation step, wherein the membrane formation step is a step of producing a crosslinked polymer composite membrane using a membrane precursor solution formed in the crosslinking step. In one embodiment, a precursor film is formed by casting a film forming precursor solution on a flat plate; A drying step of drying the cast precursor film to remove the solvent and the cross-linking agent contained in the precursor film; And immersing the dried precursor film in a basic aqueous solution.

Next, the crosslinked polymer electrolyte composite membrane of the present invention comprises a cation-conducting polymer, an anion-conducting polymer, and a unit bonding unit comprising at least one ion-crosslinked bond formed between the cation-conducting polymer and the anion-conducting polymer; And a plurality of ionic bridges formed between the unit bonding units.

Here, the cation-conducting polymer and the anion-conducting polymer constituting the unit-bonding unit are not limited, but may be the cation-conducting polymer and the anion-conducting polymer described above as an embodiment. More specifically, a unit combining unit may be implemented as shown in FIG.

Therefore, the crosslinked polymer electrolyte composite membrane of the present invention has a very strong mechanical strength of 40 MPa or more as well as VO ^{2 +} Ion permeability is significantly lowered to 4.0 ㅧ 10 ^-9 ㎠ / min or less.

As described above, the crosslinked polymer electrolyte composite membrane of the present invention can exhibit strength and durability improved by 50% or more as compared with conventional polymer electrolyte membranes, and exhibits excellent dimensional stability and mechanical strength of 40 MPa or more even under direct contact with high temperature water Therefore, the energy storage device such as the redox flow cell or the fuel cell including the crosslinked polymer electrolyte composite membrane of the present invention can improve the long-term performance.

Example 1

1. Preparation of Polymer Solution Having Cationic Conductivity

A 3 wt% solution of PPO and Chloroform was added to a 300 ml volume three-necked beaker. A 3 wt% solution was prepared and stirred vigorously. A 5 wt% CSA solution dissolved in Chloroform was prepared and dripped at room temperature for 24 hours Strongly stirred. The resulting sulfonated polyphenylene oxide (sPPO) was washed with distilled water, dried and dissolved in NMP to prepare a 10 wt% cationic polymer solution.

2. Preparation of Polymer Solution Having Anionic Conductivity

(1) Bromination step of brominating an aromatic hydrocarbon-based polymer

12 g of PPO (polyphenylene oxide) is dissolved in 100 cc of chlorobenzene as a solvent in a three-necked reactor for 20 minutes. Then, 9.8 g of N-bromosuccinimide (NBS) and 0.5 g of AIBN are added and stirred. At this time, the stirring speed in the reactor is maximized to proceed for 3.5 hours. After 7 hours, the temperature of the reactor was maintained at 140 占 폚 for 3 hours or more. The reaction mixture was placed in a beaker for 20 minutes in ice water. After stirring, the mixture was precipitated in 500 cc of isopropyl alcohol (IPA) and filtered. The IPA washing process was performed one more time, and then the reaction was resolved by precipitating in 120 cc of Chloroform. The solution was subjected to IPA precipitation and filtration to obtain a brominated aromatic hydrocarbon polymer, i.e., B-PPO (or BPPO). The obtained B-PPO was dried in an oven at 55 캜 under vacuum for a day. To prepare the anionic conductive polymer solution, 3 g of B-PPO, 17 g of NMP and 0.42 cc of imidazole were stirred in a hot-plate at 40 ° C. for 12 hours to obtain an anionic conductive polymer solution of 10 wt%.

3. Cross-linking step

10 g of the prepared cation-conductive polymer solution, 10 g of the anionic conductive polymer solution and 0.5 g of dichloro-p-xylene were mixed and stirred for 24 hours at 40 ° C in a hot-plate to obtain a solution precursor solution.

4. Film-forming step (crosslinked polymer electrolyte composite film forming step)

The prepared precursor solution was cast on a glass plate, and then dried in an oven at 50 ° C. for 6 hours to form a precursor film. Thereafter, the precursor film formed was dried at 180 DEG C for 24 hours while being raised at 20 DEG C. [ The finally dried precursor membrane was immersed in a 1M NaOH aqueous solution for 24 hours to prepare a crosslinked polymer electrolyte membrane (Crosslinked membrane).

 Experimental Example 1

The crosslinked polyelectrolyte composite membrane prepared in the example was immersed in distilled water at room temperature for 24 hours. The ion conductive cell was fixed without removing the water on the surface of the membrane, the membrane was inserted between the electrodes, and the AC impedance of 20 kHz to 100 mHz was measured The ionic conductivity of the membrane was measured and the results are shown in FIG.

From FIG. 2, which is a graph of ion conductivity of Nafion 212 and crosslinked membrane, Nafion 212 has higher ionic conductivity than crosslinked membrane, Crosslinked membrane is much larger than that of crosslinked membrane. Crosslinked membrane showed DBR of about 50% and DS of about 28%, and the water content was measured to be low, and the ion conductivity tended to be low.

Experimental Example 2

The tensile force (kpsi) of the crosslinked polymer electrolyte membrane (Crosslinked membrane) was measured according to the method described in ASTM 882, and the results are shown in FIG. Here, the mechanical strength is greatly influenced by the measurement conditions, and the experiment was conducted at 100 mm / min.

From FIG. 3, which is a result of measurement of the tensile strength of Nafion 212 and crosslinked polymer electrolyte membrane (crosslinked membrane), it can be seen that the crosslinked polymer electrolyte composite membrane exhibits a very high tensile strength characteristic as compared with Nafion 212.

Example 2

A crosslinked membrane was prepared using the battery system (857 redox cell test system, Scribner associated) shown in FIG. 4 including the crosslinked polymer electrolyte composite membrane (Crosslinked membrane) obtained in Example 1.

Comparative Example

A comparative vanadium redox flow cell (Nafion 212) was prepared in the same manner as in Example 2, except that a Nafion 212 membrane was used instead of a crosslinked polymer electrolyte composite membrane (Crosslinked membrane).

Experimental Example 3

Permeability of the crosslinked polymer electrolyte composite membrane and the Nafion 212 membrane was measured using the battery system comprising the crosslinked polymer electrolyte composite membrane and the Nafion 212 membrane prepared in Example 2 and Comparative Example. The equipment configuration is the same as the cell test, and the tank is equipped with different solutions. In order to achieve electronic equilibrium, 1.5M MgSO4 solution in 3M H2SO4 solution was added to one tank and the solution was dissolved in 1.5M VOSO4 solution in the other tank. A solution of the tank containing the magnesium sulfate solution at 1, 2, 4, 8, 12, and 24 hour intervals was sampled. The amount of transmitted VO ²⁺ was measured using UV, and the wavelength used in the measurement was 765.5 nm. The permeation amount was calculated by the following formula, and the results are shown in Table 1 and FIG.

Here, the transmission rate (Permeability) The experiment electrolyte vessel for one VRFB (A) has 1.5M VOSO ₄ /3.0MH ₂ SO _4, the other end (B) is put into a 1.5M MgSO ₄ /3.0MH ₂ SO ₄ solution and a unit cell assembled Both solutions were pumped to the cell side and the concentration was measured by taking the solution (B) over time.

Nafion 212 sPPO Im-bPPO Crosslinked membrane Permeability
(cm < ² > / min) 1.41 × 10 ^-6 5.41 × 10 ^-9 1.75 × 10 ^-8 4.03 × 10 ^-9

Nafion 212, sPPO, Im-bPPO, and VO ²⁺ ions of the crosslinked polymer electrolyte composite membrane From Table 1 and FIG. 5 showing the change in the permeability and the concentration of VO ²⁺ (V (V)) over time, the permeability was measured as 1.41 × 10 ^-6 cm ^{2 /} min for Nafion 212 and sPPO, Im-bPPO, The polymer electrolyte composite membranes were 5.41 × 10 ^-9 , 1.75 × 10 ^-8 , 4.03 × 10 ^-9 , cm ² / min. The cross-linked polymer electrolyte membranes showed very low permeation of VO ²⁺ ions compared to Nafion 212 and other hydrocarbon-based polymer membranes.

Experimental Example 4

A cyclic voltammogram of a vanadium redox flow cell (RFB) was carried out on a crosslinked membrane obtained in Example 2 and a comparative vanadium redox flow cell (Nafion 212) obtained in Comparative Example under a condition of 40 mA / cm 2 And Coulombic efficiency (CE) was measured. The results are shown in FIG.

As shown in FIG. 6, the efficiency of the crosslinked membrane was higher than that of Nafion 212 in CE.

From FIG. 6, it can be seen that the crosslinked membrane using the polymer electrolyte composite membrane of the present invention as an ion exchange membrane, compared to the vanadium redox flow cell (Nafion 212), which uses Nafion as an ion exchange membrane, And the long-term operation performance can be improved as well.

The above-described experimental results illustrate only the case where the polymer electrolyte composite membrane of the present invention is used in a redox flow cell. However, even when used in an energy storage device such as another kind of secondary battery or a fuel cell, It can be predicted that performance can also be improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, Various changes and modifications will be possible.

Claims (15)

Preparing a cationic conductive polymer solution by dissolving the cationic conductive polymer in a solvent; Preparing an anionic conductive polymer solution by dissolving an anionic conductive polymer in a solvent; And a cross-linking step of mixing and crosslinking the cation-conductive polymer solution, the anion-conducting polymer solution and the cross-linking agent to form a solution precursor solution,
The cationic conductive polymer may be at least one selected from the group consisting of sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (S-PEEK) Sulfonated polybenzimidazole (S-PBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene, Poly (phenylene oxide) (S-PPO), and combinations thereof.
The anionic conductive polymer may be selected from the group consisting of Im-bPPO, Chloromethylated bPPO, poly (1-allyl-3-methylimidazolium chloride and methyl methacrylate), ETFE-g-PDMAEMA (ethylene-tetrafluoroethylene-dimethylaminoethyl methacrylate), cardo-polyetherketone, chloromethylated / quaternized poly phthalazinone ether ketone), ethylene-tetrafluoroethylene-dimethylaminoethyl methacrylate (DMAEMA), quaternary ammonium functionalized PAES, quaternary benzyl trimethylammonium, quaternized poly (phthalazinone ether sulfone ketone)
The crosslinking agent used in the crosslinking step may be selected from the group consisting of dichloro xylene, xylylenediamine, o-xylylenediamine dihydrochloride, xylylenediamine / acrylonitrile adduct, 2,3,5,6-tetramethyl-1,4-xylylenediamine dihydrochloride, xylylenediamine dihydrochloride, and more preferably at least one selected from the group consisting of xylylenediamine dihydrochloride,
Wherein the crosslinking step is performed by mixing the cationic conductive polymer solution, the anionic conductive polymer solution, and the crosslinking agent, followed by stirring at 35 to 45 ° C.
delete delete The method according to claim 1,
The solvent may be an alcohol-based solvent including methanol, ethanol, propanol, isopropanol, butanol, and isobutanol; Ether-based solvents including diethyl ether, dipropyl ether, dibutyl ether, butyl ethyl ether, and tetrahydrofuran; Alcohol ether solvents including ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; Ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; An amide-based solvent including N-methyl-2-pyrrolidinone, 2-pyrrolidinone, N-methylformamide and N, N-dimethylformamide; A sulfoxide-based solvent containing dimethylsulfoxide and diethylsulfoxide; Diethylsulfone, and tetramethylene sulfone; Nitrile solvents including acetonitrile, benzonitrile; Amine-based solvents including alkylamines, cyclic amines, and aromatic amines; Ester solvents including methyl butyrate, ethyl butyrate and propyl propionate; A carboxylic acid ester-based solvent containing ethyl acetate and butyl acetate; Aromatic hydrocarbon solvents including benzene, ethylbenzene, chlorobenzene, toluene and xylene; An aliphatic hydrocarbon-based solvent including hexane, heptane, and cyclohexane; Halogenated hydrocarbon-based solvents including chloroform, tetrachlorethylene, carbon tetrachloride, dichloromethane, and dichloroethane; Wherein the polymer electrolyte membrane is at least one selected from the group consisting of propylene carbonate, ethylene carbonate, dimethyl carbonate, dibutyl carbonate, ethyl methyl carbonate, dibutyl carbonate, nitromethane and nitrobenzene.
delete delete The method according to claim 1,
Further comprising a film forming step of producing a crosslinked polymer composite membrane using the film forming precursor solution formed in the crosslinking step. 8. The method of claim 7,
Forming a precursor film by casting the film forming precursor solution on a flat plate; A drying step of drying the cast precursor film to remove the solvent and the cross-linking agent contained in the precursor film; And a step of immersing the dried precursor membrane in a basic aqueous solution.
A unit bonding unit comprising at least one cationic conductive polymer, an anionic conductive polymer, and at least one ionic crosslinking formed between the cationic conductive polymer and the anionic conductive polymer; And
And a plurality of ionic crosslinks formed between the unit binding units,
The cationic conductive polymer may be at least one selected from the group consisting of sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (S-PEEK) Sulfonated polybenzimidazole (S-PBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene, Poly (phenylene oxide) (S-PPO), and combinations thereof.
The anionic conductive polymer may be selected from the group consisting of Im-bPPO, Chloromethylated bPPO, poly (1-allyl-3-methylimidazolium chloride and methyl methacrylate), ETFE-g-PDMAEMA (ethylene-tetrafluoroethylene-dimethylaminoethyl methacrylate), cardo-polyetherketone, chloromethylated / quaternized poly phthalazinone ether ketone), ethylene-tetrafluoroethylene-dimethylaminoethyl methacrylate (DMAEMA), quaternary ammonium functionalized PAES, quaternary benzyl trimethylammonium, quaternized poly (phthalazinone ether sulfone ketone)
Wherein the membrane has a VO ²⁺ ion permeability of 4.0 × 10 ^-9 cm 2 / min or less and a mechanical strength of 40 MPa or more.
delete delete delete delete 9. An energy storage device comprising a crosslinked polymer electrolyte composite membrane produced by the method of any one of claims 1, 4, 7, and 8 or a crosslinked polymer electrolyte composite membrane of claim 9.
15. The method of claim 14,
Wherein the energy storage device is a redox flow cell or a fuel cell.

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