Method for manufacturing thin film composite separation membrane for alkaline water electrolysis

Abstract

The present invention relates to a method for manufacturing a thin film composite separator for alkaline water electrolysis, and a thin film composite separator for alkaline water electrolysis. The present invention can provide a thin film composite separator having low mass transfer resistance and high ion conductivity and excellent water electrolysis performance compared to conventional dense separators and porous separators, while minimizing gas mixing by reducing gas permeability, thereby providing high safety.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a thin film composite separator for alkaline water electrolysis and a thin film composite separator for alkaline water electrolysis produced thereby. [Background technology]

[0002] A water electrolysis system is a method of generating hydrogen by electrolyzing water. An electrolyte solution is continuously supplied to each electrode, and hydrogen and oxygen gases are generated at the cathode and anode, respectively.

[0003] Alkaline water electrolysis is a water electrolysis technology that uses an alkaline electrolyte solution containing hydroxide ions, which move between the cathode and anode and mediate the reaction between the two electrodes. Because the alkaline electrolyte environment is a basic atmosphere, it has the advantage of being able to use relatively inexpensive non-precious metals such as nickel (Ni) or silver (Ag) as catalysts.

[0004] In alkaline water electrolysis, a separator membrane is placed between the two electrodes, which plays a key role in controlling the transport of materials and ions between the electrodes. For a separator membrane to be effectively used in an alkaline water electrolysis system, it must have high hydroxide ion conductivity and reduce the voltage load required during water electrolysis. In addition, because there is a risk of explosion when the concentration of hydrogen in oxygen increases above 4%, the separator membrane must have low permeability to the hydrogen and oxygen gases produced at the cathode and anode, respectively.

[0005] Conventional alkaline water electrolysis mainly uses porous separators. A representative commercially available alkaline water electrolysis separator is Zirfon® from Belgium's Agfa, which is manufactured by coating a polyphenylene sulfide support with a solution of zirconium oxide (ZrO2) nanoparticles / polysulfone through a phase transition, resulting in a porous structure.

[0006] Zirfon® has the advantages of excellent alkaline stability and low mass transfer resistance due to its porous structure. However, due to its large surface pore size (150 nm) and high porosity (55%), it has high gas permeability, allowing the generated oxygen and hydrogen to easily permeate, increasing the risk of explosion due to gas mixing. Furthermore, the thick (500-600 μm) separator structure results in a large gap between electrodes, which causes problems with high area-specific resistance.

[0007] Therefore, in order to reduce the risks caused by the high gas permeability of conventional porous separation membranes, high-density separation membranes with low gas permeability have been researched. However, high-density separation membranes have limitations in that they have high mass transfer resistance, high voltage load, and low mechanical strength and thermochemical stability, which restrict their operating conditions. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to solve the shortcomings of conventional porous and dense separation membranes by providing a thin film composite separation membrane that exhibits high ionic conductivity while reducing mass transfer resistance by increasing mechanical strength and thermochemical stability, and at the same time reduces the permeability of gases generated during water electrolysis, minimizing gas mixing and ensuring safety. [Means for solving the problem]

[0009] The present invention provides a method for preparing a thin film composite separator for alkaline water electrolysis, which includes forming a crosslinked quaternary ammonium polymer selective layer on a porous support or within the pores of the porous support through Menshutkin polymerization.

[0010] The present invention further comprises a porous support, and a selective layer formed on one side, both sides, or within the pores of the porous support; The selective layer is formed on a porous support through Menshutkin polymerization, or provides a thin film composite separation membrane that is a crosslinked quaternary ammonium polymer that has a pore-filling form within the pores of the porous support.

[0011] The present invention further provides a method for producing a thin film composite separator for alkaline water electrolysis, the method comprising the step of hydrophilizing a porous support, and a thin film composite separator for alkaline water electrolysis, the thin film composite separator comprising the hydrophilized porous support. [Effects of the Invention]

[0012] The thin film composite separator according to the present invention provides a thermochemically stable separator for alkaline water electrolysis by hydrophilizing a porous support, and by coating a thin film selective layer on the porous support, it has low mass transfer resistance and high ionic conductivity, and can prevent gas permeation and mixing by reducing gas permeability while providing excellent water electrolysis performance. As a result, it is possible to provide a thin film composite separator that can implement an alkaline water electrolysis process with high safety and hydrogen production efficiency. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating a method for producing a thin-film composite separation membrane for alkaline water electrolysis utilizing a Menshutkin polymerization reaction. [Figure 2] 1 shows an image of the surface structure of a 20 μm thick porous support confirmed by a scanning electron microscope. [Figure 3] 1 shows images of the surface structure of the support before and after the hydrophilization treatment of Example 2 according to Experimental Example 1, as confirmed by a scanning electron microscope. [Figure 4] 1 shows images of the surface structures of the separation membranes of Examples 2 and 3 according to Experimental Example 1, as observed through a scanning electron microscope. [Figure 5] 10 is a graph comparing voltage load values ​​when a water electrolysis system is operated in a 1 M potassium hydroxide solution according to Experimental Example 6. [Figure 6]10 is a graph comparing voltage load values ​​when a water electrolysis system is operated in a 6 M potassium hydroxide solution according to Experimental Example 6. [Figure 7] 10 is a graph comparing voltage load values ​​when a water electrolysis system is operated in a 6 M potassium hydroxide solution according to Experimental Example 6. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will now be described in further detail.

[0015] Meanwhile, each description and embodiment disclosed herein may also be applied to each other description and embodiment. That is, all combinations of various elements disclosed herein fall within the scope of the present invention. In addition, the specific description below should not be construed as limiting the scope of the present invention.

[0016] When a part is said to "comprise" certain elements, this does not mean that it excludes other elements, but that it may further comprise other elements, unless specifically stated to the contrary.

[0017] The present invention provides a method for producing a thin film composite separator using Menshutkin polymerization.

[0018] Specifically, the present invention provides a method for manufacturing a thin film composite separator for alkaline water electrolysis, which includes forming a quaternary ammonium polymer thin film selective layer on a porous support or within the pores of the porous support through a Menschutkin polymerization reaction.

[0019] The Menshutkin reaction is a reaction in which a tertiary amine reacts with an alkyl halide to produce a quaternary ammonium compound. The Menshutkin polymerization reaction according to the present invention forms a crosslinked quaternary ammonium polymer through the Menshutkin reaction. When a high-density crosslinked quaternary ammonium polymer selective layer is formed on or within the pores of a porous support by the Menshutkin polymerization reaction, it is possible to ensure safety by reducing gas permeability, and to improve water electrolysis performance by exhibiting strong alkaline stability and high ionic conductivity.

[0020] In the present invention, the porous support may be a polyolefin, and a commercially available product may be used, or a synthesized product may be used.

[0021] In one embodiment, the porous support is made of polyethylene, polypropylene, polymethylpentene, polybutene-1, polyolefin elastomer, polyisobutylene, ethylene propylene rubber, polysulfone, polyacetylene, polyisobutylene, polyvinylchloride, Teflon (registered trademark) (polytetrafluoroethyne), polyphenylene sulfide, polyacrylonitrile, polyethersulfone, polystyrene, polydimethylsiloxane, polyvinylfluoride, ethylene vinyl alcohol, polyvinyl alcohol At least one polymer component selected from the group consisting of polyvinyl alcohol, polybenzimidazole, polyvinylpyrrolidone, polyetherimide, polyvinylidene fluoride, and polyetheretherketone may be used.

[0022] In one embodiment, the type of porous support is not particularly limited, but preferably, a polyolefin support such as polyethylene or polypropylene may be used.

[0023] In one embodiment, the weight average molecular weight of the porous polyolefin support is 10,000 to 5,000,000 g mol-1 may be.

[0024] In one embodiment, the porous polyolefin support may have a water contact angle of 120 degrees or less.

[0025] In one embodiment, the porous polyolefin support may be manufactured through a dry process based on a stretching process or a wet process based on an extraction process, and more preferably through a wet process.

[0026] In one embodiment, the porous polyolefin support may be manufactured by melt-extruding the polymer and diluent constituting the support, followed by liquid-liquid phase separation to form a sheet, followed by stretching. Here, the content of the diluent may be 10 to 80 wt% based on the total weight, and the diluent may be an organic liquid compound such as an aliphatic or cyclic hydrocarbon (e.g., nonane, decane, paraffin oil, decalin), or a phthalic acid ester (e.g., dibutyl phthalate, dioctyl phthalate).

[0027] When preparing the porous polyolefin support, general additives may be further included to improve specific functions, such as UV stabilizers, antistatic agents, oxidation stabilizers, and organic / inorganic nucleating agents, if necessary.

[0028] In one specific example, the pore size of the porous support is not particularly limited, but may be 0.5 nm to 100 μm. Specifically, the pore size may be 10 μm or less, 1 μm or less, 500 nm or less, 200 nm or less, or 100 nm or less, and more specifically, 1 nm to 10 μm, 1 nm to 1 μm, or 1 to 100 nm.

[0029] In one specific example, the porosity of the porous support is not particularly limited, but may be 0.5 to 90%, and specifically, may be 10 to 90%.

[0030] In one specific example, the thickness of the porous support is not particularly limited, but may be 1 to 1000 μm, more specifically, 1 to 100 μm, 1 to 50 μm, 3 to 40 μm, or 5 to 30 μm.

[0031] The manufacturing method of the present invention may further include a step of hydrophilizing the porous support before forming the crosslinked quaternary ammonium polymer selective layer.

[0032] When performing hydrophilization treatment, hydrophilicity may be imparted to a hydrophobic porous support, which can improve hydroxide ion conductivity while reducing gas permeability, making it easier to form a selective layer.

[0033] The hydrophilization treatment may be carried out on one or both surfaces of the porous support, or on the surface within the pores.

[0034] The hydrophilization treatment of the porous support may be performed by at least one of plasma, atomic layer deposition, chemical vapor deposition, inorganic coating, organic coating, or chemical oxidation treatment, and more preferably, by organic coating treatment.

[0035] The organic coating may be an oligomer or polymer containing a hydrophilic functional group such as hydroxyl, carboxyl, amine, etc. For example, the organic coating may be at least one polymer component selected from the group consisting of polyvinyl alcohol, ethylene vinyl alcohol, polydopamine, polyacrylic acid, polymethacrylic acid, polyethylene glycol, polypropylene glycol, polyetherimide, tannic acid, polyvinylamine, poly(4-styrene sulfonic acid), poly(vinylsulfonic acid), polyethyleneimine, polyaniline, polyvinyl pyrrolidone, and cellulose-based polymers.

[0036] The hydrophilization treatment may further include a step of crosslinking after coating with an organic material to enhance the stability of the organic coating.

[0037] The crosslinking may be performed using at least one component selected from the group consisting of glyoxal, glutaraldehyde, epichlorohydrin, boric acid, maleic acid, citric acid, and tetraethylorthosilicate.

[0038] In the present invention, the method may further include washing the porous support after the hydrophilization treatment, and the washing solvent may be isopropyl alcohol, water, or a mixture thereof.

[0039] The selective layer may be formed on a hydrophilized porous support or within the pores of the hydrophilized porous support through a Menschutkin polymerization reaction. The selective layer may be formed on one side, both sides, or within the pores of the porous support.

[0040] When the selective layer is formed in the pores of the porous support, the selective layer may be pore-filled in the pores of the porous support.

[0041] When the selective layer is formed on a porous support, the thickness of the selective layer may be 1 to 100 μm, 1 to 50 μm, 3 nm to 1 μm, 5 to 500 nm, or 5 to 200 nm.

[0042] The Menschutkin polymerization reaction may be carried out by an interfacial polymerization method, a dip coating method, a spin coating method, a layer-by-layer method, a slot coating method, or a spray coating method, and more preferably by an interfacial polymerization method.

[0043] The selective layer according to the present invention may be formed by impregnating or coating a porous support with a first solution containing a tertiary amine-based monomer and a second solution containing an alkyl halide-based monomer, and then polymerizing the monomers in the first and second solutions.

[0044] Here, the impregnation or application of the first and second solutions may be performed by first impregnating or applying the first solution containing a tertiary amine monomer to the porous support, and then impregnating or applying the second solution containing an alkyl halide monomer, or conversely, by first impregnating or applying the second solution and then impregnating or applying the first solution, or by simultaneously impregnating or applying the first and second solutions.

[0045] The solvent of the first solution and the solvent of the second solution for the polymerization reaction may be different from each other and may exhibit immiscibility with each other.

[0046] The tertiary amine monomer is not particularly limited as long as it is a monomer containing a tertiary amine group that can form a crosslinked quaternary ammonium polymer as a reactant of the Menschutkin polymerization reaction.

[0047] The tertiary amine monomer may contain two or more tertiary amine groups, and when it contains two or more tertiary amine groups, it can easily form a crosslinked polymer by reacting with an alkyl halide monomer.

[0048] The tertiary amine monomer has a molecular weight of 50 to 1,000,000 g mol -1 It may be a range of substances.

[0049] The tertiary amine monomers include N,N,N',N'-tetramethylmethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N',N''-pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetriamine, and 1,1,4,7,10,10-hexamethyltriethylenetriamine. Tetramine (1,1,4,7,10,10-hexamethyltriethylenetetramine), tris[2-(dimethylamino)ethyl]amine, tris(dimethylamino)methane, tetramethyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,4-butanediamine (N,N,N',N' -tetramethyl-1,4-butanediamine, N,N,N',N'-tetramethyl-1,6-hexamethylenediamine, 1,4-dimethylpiperazine, 1,4,7-trimethyl-1,4,7-triazacyclononane, 1,4,8,11-tetramethyl-1,4,8,11 -Tetraazacyclotetradecane (1,4,8,11-tetramethyl-1,4,8,11-tetraazacylcotetradecane), N,N,N',N'-tetramethyl-1,4-phenylenediamine (N,N,N',N'-tetramethyl-1,4-phenylenediamine), N,N,N',N'-tetramethyl-1,3-phenylenediamine (N,N,N',N'-tetramethyl-1,3-phenylenediamine), 1,4-bis(diphenylamino)benzene (1,It may be at least one selected from 4-bis(diphenylamino)benzene), 4,4'-trimethylenebis(1-methylpiperidine) (4,4'hexamine), altretamine, and polyethyleneimine, and most preferably N,N,N',N',N''-pentamethyldiethylenetriamine.

[0050] In one specific example, the type of solvent for the first solution containing a tertiary amine-based monomer is not particularly limited, and for example, at least one selected from the group consisting of water, methanol, ethanol, propanol, butanol, isopropanol, ethyl acetate, acetone, chloroform, tetrahydrofuran, dimethyl sulfoxide, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dimethylformamide, N-methyl-2-pyrrolidone, acetophenone, and acetonitrile may be used. When the tertiary amine monomer is N,N,N',N',N''-pentamethyldiethylenetriamine, a preferred solvent for the first solution may be dimethyl phthalate.

[0051] The alkyl halide monomer is not particularly limited as long as it is a monomer containing an alkyl halide group that can form a crosslinked quaternary ammonium polymer thin film as a reaction product of the Menschutkin polymerization reaction.

[0052] The alkyl halide monomer may contain at least two alkyl halide groups. When the alkyl halide monomer contains two or more alkyl halide groups, it can easily react with a tertiary amine monomer to form a crosslinked polymer.

[0053] The alkyl halide monomer has a molecular weight of 50 to 1,000,000 g mol -1 It may be a range of substances.

[0054] The alkyl halide monomers include 1,2-dichloroethane, 1,3-dichloropropane, 1,3-dibromopropane, 1,4-dichlorobutane, 1,4-dibromobutane, 1,4-dibromobutane, 1,4-diodobutane, and 1,6-dichlorohexane. (1,6-dichlorohexane), 1,2-bis(bromomethyl)benzene, 1,2-bis(bromomethyl)benzene, 1,3-bis(bromomethyl)benzene, 1,4-bis(bromomethyl)benzene, 1,3,5-tris(bromomethyl)benzene, It may be at least one selected from 2,6-bis(bromomethyl)naphthalene and 1,4-bis(1,2-dibromoethyl)benzene, and most preferably 1,3,5-tris(bromomethyl)benzene.

[0055] In one specific example, the type of solvent for the second solution containing an alkyl halide monomer is not particularly limited, and for example, at least one selected from the group consisting of n-hexane, pentane, cyclohexane, heptane, octane, decane, dodecane, tetrachloromethane, benzene, xylene, toluene, chloroform, tetrahydrofuran, N-methyl-2-pyrrolidone, acetophenone, acetonitrile, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dimethylformamide, and isoparaffin may be used. When the alkyl halide monomer is 1,3,5-tris(bromomethyl)benzene, a preferred solvent for the second solution may be n-hexane.

[0056] In one embodiment, when the mixing of the solvents of the first and second solutions is increased during interfacial polymerization, a thin film composite separation membrane may be produced in which the selective layer is pore-filled within a porous support.

[0057] The present invention further provides a crosslinked quaternary ammonium polymer thin film composite separation membrane, which includes a porous support and a selective layer formed on one side, both sides, or within the pores of the porous support, wherein the selective layer is formed on the porous support through Menshutkin polymerization or has a form engineered and filled within the pores of the porous support.

[0058] The thin film composite separator according to the present invention may be manufactured by the above-described method for manufacturing a thin film composite. The thin film composite separator according to the present invention has high ionic conductivity and low mass transfer resistance, exhibiting high water electrolysis performance, and also has low gas permeability, preventing gas mixing and ensuring safety.

[0059] The above-described content relating to the thin film composite separation membrane of the present invention may be similarly applied to the method for producing the thin film composite separation membrane.

[0060] In one embodiment, the porous support according to the present invention may be a porous support that has been hydrophilized. The hydrophilization treatment is the same as that described above in the method for manufacturing the thin film composite separator.

[0061] The present invention also provides a method for preparing a thin film composite separator for alkaline water electrolysis, which includes a step of hydrophilizing a porous support.

[0062] Here, the description of the hydrophilization treatment and the porous support may be similarly applied to the method for manufacturing the thin film composite separator using the Menschutkin polymerization reaction.

[0063] Without a selective layer, the hydrophilic treatment of the porous support alone can provide superior water electrolysis performance, lower gas permeability, and higher safety than commercially available porous separators.

[0064] The hydrophilization treatment may be performed by organic coating, which is easy to form since a hydrophilic polymer is bound to the porous support through hydrophobic interaction.

[0065] In one specific example, the porous support may be polyolefin, and the hydrophilization treatment may be performed by coating ethylene vinyl alcohol on the polyolefin.

[0066] The present invention provides a thin film composite separator for alkaline water electrolysis, further comprising a hydrophilically treated porous support. Such a thin film composite separator may be manufactured by a manufacturing method including a step of hydrophilizing the porous support. In addition, the same description as given above for the method for manufacturing a thin film composite separator using the Menschutkin polymerization reaction may be applied to the hydrophilization treatment and the porous support.

[0067] Preferred examples and experimental examples are presented below to aid in understanding the present invention. However, the following examples and experimental examples are provided merely to facilitate understanding of the present invention, and the contents of the present invention are not limited to the following examples and experimental examples.

[0068] Example Material selection (1) Porous support: We used porous polyethylene supports manufactured using a wet process. Two similar structures were prepared: a 9 μm thick polyethylene support (surface pore size <100 nm, porosity 51%) and a 20 μm thick polyethylene support (surface pore size <100 nm, porosity 47%).

[0069] FIG. 2 shows a cross-sectional view of a 20 μm thick polyethylene support. The polyethylene support has a similar structure on the front and back sides, and has a uniform cross-sectional structure with excellent pore connectivity.

[0070] (2) Hydrophilic treatment material: Ethylene vinyl alcohol was used as the hydrophilic coating material for the support, and isopropanol and water were used as the solvent for dissolving the hydrophilic coating material.

[0071] (3) Menshutkin polymerization reaction monomers and solvents for the selective layer fabrication: Interfacial polymerization, a polymerization reaction between monomers dissolved in two immiscible solvents, was utilized. The solvents used were dimethyl phthalate and n-hexane, and the tertiary amine monomer contained therein was N,N,N',N',N''-pentamethyldiethylenetriamine, and the alkyl halide monomer was 1,3,5-tris(bromomethyl)benzene.

[0072] (4) Comparative Examples 1 and 2 As Comparative Example 1, a commercially available porous separation membrane, Zirfon (registered trademark) separation membrane manufactured by Agfa, was prepared. As Comparative Example 2, a commercial high-density separation membrane, FAA-3-50 separation membrane manufactured by Fumatec Co., Ltd., was prepared.

[0073] Production Example 1. Production of the support of Example 1 The support of Example 1 was manufactured through the following step (1).

[0074] (1) Hydrophilization of porous support Ethylene vinyl alcohol is added to a solvent of isopropanol and water in equal volume ratios at 0.5gL. -1The solution was heated to 80°C to dissolve the solution, and then cooled to 25°C. A 9μm thick polyethylene support (surface pore size <100nm, porosity 51%) was supported on the solution for 24 hours. After the support, the support was washed with water to remove residual solvent and then dried in an oven at 90°C for 1 hour.

[0075] Production Example 2: Production of the support of Example 2 The support of Example 2 was prepared in the same manner as in Preparation Example 1, except that the polyethylene support was changed to a polyethylene support having a thickness of 20 μm (surface pore size <100 nm, porosity 47%).

[0076] Preparation Example 3: Preparation of separation membrane of Example 3 The separation membrane of Example 3 was prepared by further performing the following step (2) in addition to the above Preparation Example 2.

[0077] (2) Formation of a selective layer on a porous support using the Menshutkin interfacial polymerization reaction A high-density thin film selective layer was synthesized on a previously prepared hydrophilized porous polyethylene support by using the Menshutkin interfacial polymerization reaction.

[0078] 1) N,N,N',N',N''-pentamethyldiethylenetriamine in dimethyl phthalate solvent 100g L -1 After dissolving in HCl, the hydrophilized polyethylene support was left to support for 1 hour.

[0079] 2) The loaded support was taken out and excess solution on the surface was removed with a roller. Then, 2 g of 1,3,5-tris(bromomethyl)benzene was dissolved in n-hexane. -1 The mixture was supported in a solution of 1,000 ppm ammonium hydroxide and reacted at 25°C for 24 hours.

[0080] 3) After the reaction, the separation membrane was taken out, and the solution remaining on the surface was washed with n-hexane and dried at 25°C for 5 minutes.

[0081] 4) To further crosslink unreacted monomers, the mixture was reacted in an oven at 70°C for 5 minutes.

[0082] 5) Then, the catalyst was supported in a 1M potassium hydroxide solution for more than 1 hour, and the bromo ions (Br-) generated after the reaction were exchanged for hydroxide ions (OH-).

[0083] Experimental Example 1: Surface observation of support / separation membrane The surface of the support of Example 2 prepared in Preparation Example 2 was observed at various positions using a scanning electron microscope, and the results are shown in FIG.

[0084] As shown in Figure 3, it can be seen that the porous structure of the polyethylene support is maintained even after the hydrophilic coating. In particular, the size of the surface pores of the hydrophilized polyethylene support is approximately 100 nm or less, which is smaller than the size of the surface pores (approximately 150 nm) of the commercial Zirfon® separator in Comparative Example 1, and this indicates that gas permeation can be reduced.

[0085] Meanwhile, the surface of the separation membrane of Example 3 prepared in Preparation Example 3 was observed at various positions using a scanning electron microscope, and the results are shown in Figure 4. As shown in Figure 4, when the selective layer was synthesized on the hydrophilic porous support, the surface pore structure was clogged, confirming the formation of a thin film composite.

[0086] Experimental Example 2: Confirmation of hydrophilicity of the support In Preparation Examples 1 and 2, the hydrophilicity of the polyethylene substrate before and after the hydrophilic coating with ethylene vinyl alcohol was confirmed by measuring the water contact angle, and the results are shown in Table 1 below.

[0087] [Table 1]

[0088] As shown in Table 1, the polyethylene substrates of Examples 1 and 2, which have different thicknesses of 9 μm and 20 μm, all showed significantly lower water contact angles after ethylene vinyl alcohol coating, confirming that hydrophilicity was improved through the coating.

[0089] Experimental Example 3: Gas permeability characteristics Dissolved hydrogen permeability was measured to evaluate the gas permeability of Examples 1 to 3 and Comparative Example 1. The dissolved hydrogen permeability was evaluated using water permeability, which was measured using distilled water as raw water at 25°C using a dead-end cell device.

[0090] Specifically, the amount of distilled water permeated at the measurement pressure (differential pressure) was measured to calculate the water permeability, and the dissolved hydrogen permeability was calculated assuming that the distilled water was saturated with hydrogen gas. The results are shown in Table 2 below.

[0091] [Table 2]

[0092] As shown in Table 2, the supports or thin film composite separators of Examples 1 to 3 were found to have very low dissolved hydrogen permeability compared to the commercial porous separator (Zirfon) of Comparative Example 1. These results confirmed that when a polyethylene support or a thin film composite separator based thereon is applied to a water electrolysis system, it has low gas permeability, ensuring safety, and is able to operate flexibly in response to load fluctuations because gases do not permeate well even during low-load operation.

[0093] Experimental Example 4: Measurement of area specific resistance The area specific resistances of Examples 1 to 3 and Comparative Example 1 were measured by impedance spectroscopy using an H-type electrolytic cell. A 2M potassium hydroxide solution at 25° C. was used as the alkaline electrolyte. The measured area specific resistances are shown in Table 3 below.

[0094] [Table 3]

[0095] As shown in Table 3, the supports or separators of Examples 1 to 3 of the present invention have significantly lower area specific resistances than the commercial porous separator (Zirfon) of Comparative Example 1. This result indicates that when a polyethylene support or a thin film composite separator based thereon is applied to a water electrolysis system, it has low area specific resistance and can operate the water electrolysis system efficiently.

[0096] Experimental Example 5: Measurement of mechanical strength The mechanical strength of Examples 2 and 3 and Comparative Examples 1 and 2 was measured using a universal testing machine. 2 The support or separator (5 mm x 15 mm) was stretched at a speed of 20 mm / min while wet with distilled water and measured, and the measured mechanical strength is shown in Table 4 below.

[0097] [Table 4]

[0098] As shown in Table 4, the supports or separators of Examples 2 and 3 of the present invention have higher mechanical strength than the commercial porous separator (Zirfon) of Comparative Example 1 and the commercial high-density separator (FAA-3-50) of Comparative Example 2. This result indicates that when a polyethylene support or a thin film composite separator based thereon is applied to a water electrolysis system, dimensional stability due to its high mechanical strength can be ensured, enabling stable operation of the water electrolysis system.

[0099] Experimental Example 6. Voltage Load Characteristics The performance of Examples 1 to 3 and Comparative Examples 1 and 2 was evaluated by measuring the voltage due to the current.

[0100] Specifically, the reaction area is 20 cm 2Measurements were performed using a load cell capable of evaluating performance while maintaining a constant clamping pressure (200 kgf). The electrolytes used were 1M (measurement conditions for commercial high-density separators) and 6M (measurement conditions for commercial porous separators) potassium hydroxide solutions at 80°C. As electrode catalysts, Raney nickel was used for the cathode and nickel-iron layered double hydroxide for the anode. Nickel foam (110 ppi) diffusers were used as electrode supports, and a nickel separator with linear channels was applied. First, the performance of Example 3 and Comparative Example 2 was compared when operating a water electrolysis system in 1M potassium hydroxide solution at 80°C. Comparative Example 2 had poor thermochemical stability and decomposed at 80°C. Therefore, the performance of Comparative Example 2 was measured at 60°C, while that of Example 3 was measured at 80°C. The results are shown in Figure 5.

[0101] As shown in Figure 5, Example 3 exhibited a similar voltage load value at the same current density as Comparative Example 2. Furthermore, unlike Comparative Example 2, which decomposed at 80°C, Example 3 could be operated at 80°C and exhibited a water electrolysis efficiency similar to that of Comparative Example 2 at a lower temperature (60°C).

[0102] Meanwhile, the performance of Examples 1 to 3 and Comparative Example 1 was compared when the water electrolysis system was operated in a 6 M potassium hydroxide solution at 80°C, and the results are shown in Figures 6 and 7. As shown in Figures 6 and 7, it was confirmed that Examples 1 to 3 exhibited lower voltage load values ​​at the same current density than Comparative Example 1, which indicates that Examples 1 to 3 all had higher water electrolysis efficiency than Comparative Example 1.

[0103] As a result, when a polyethylene support or a thin film composite separator based on it is applied to a water electrolysis system, it can be operated under various operating conditions and high hydrogen production efficiency can be expected.

Claims

1. forming a crosslinked quaternary ammonium polymer selective layer on or within the pores of a porous support through Menshutkin polymerization; the selective layer is formed by impregnating or coating the porous support with a first solution containing a tertiary amine-based monomer and a second solution containing an alkyl halide-based monomer, and then causing a polymerization reaction between the monomers in the first solution and the second solution.

2. The porous support may be polyethylene, polypropylene, polymethylpentene, polybutene-1, polyolefin elastomer, polyisobutylene, ethylene propylene rubber, polysulfone, polyacetylene, polyisobutylene, polyvinyl chloride, Teflon, polytetrafluoroethylene, polyphenylene sulfide, etc. sulfide), polyacrylonitrile, polyethersulfone, polystyrene, polydimethylsiloxane, polyvinyl fluoride, ethylene vinyl alcohol, polyvinyl alcohol, polybenzimidazole, polyvinylpyrrolidone, polyetherimide, polyvinylidene fluoride 2. The method for producing a thin film composite separator for alkaline water electrolysis according to claim 1, comprising at least one polymer component selected from the group consisting of poly(ethylene fluoride) and poly(ether ether ketone).

3. 2. The method for producing a thin film composite separator for alkaline water electrolysis according to claim 1, further comprising the step of hydrophilizing the porous support before forming the cross-linked quaternary ammonium polymer selective layer.

4. 4. The method for manufacturing a thin film composite separator for alkaline water electrolysis according to claim 3, wherein the hydrophilization treatment of the porous support is performed by at least one of plasma, atomic layer deposition, chemical vapor deposition, inorganic coating, organic coating, or chemical oxidation treatment.

5. The hydrophilization treatment of the porous support is an organic coating treatment, and the organic coating is polyvinyl alcohol, ethylene vinyl alcohol, polydopamine, polyacrylic acid, polymethacrylic acid, polyethylene glycol, polypropylene glycol, polyetherimide, tannic acid, polyvinylamine, poly(4-styrene sulfonic acid), ...

5. The method for producing a thin film composite separator for alkaline water electrolysis according to claim 4, wherein the thin film composite separator for alkaline water electrolysis is coated with at least one polymer component selected from the group consisting of poly(vinylsulfonic acid), poly(vinylsulfonic acid), polyethyleneimine, polyaniline, polybenzimidazole, polyvinylpyrrolidone, and cellulose-based polymers.

6. 6. The method for manufacturing a thin film composite separator for alkaline water electrolysis according to claim 5, wherein the organic coating treatment comprises coating the organic material and then crosslinking the coated organic material.

7. The method for producing a thin film composite separator for alkaline water electrolysis according to claim 1 , wherein the Menschutkin polymerization reaction is carried out by an interfacial polymerization method.

8. 2. The method for producing a thin film composite separation membrane for alkaline water electrolysis according to claim 1, wherein the tertiary amine monomer contains at least two tertiary amine groups, and / or the alkyl halide monomer contains at least two alkyl halide groups.

9. Tertiary amine monomers include N,N,N',N'-tetramethylmethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-pentamethyldiethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetra ... amine (1,1,4,7,10,10-hexamethyltriethylenetetramine), tris-(2-(dimethylamino)ethyl)amine (tris[2-(dimethylamino)ethyl]amine), tris(dimethylamino)methane (tris(dimethylamino)methane), tetramethyl-1,3-diaminopropane (tetramethyl-1,3-diaminopropane), tetramethyl-1,3-diaminopropane (tetramethyl-1,3-diamino propane), N,N,N',N'-tetramethyl-1,4-butanediamine (N,N,N',N'-tetramethyl-1,4-butanediamine), N,N,N',N'-tetramethyl-1,6-hexamethylenediamine (N,N,N',N'-tetramethyl-1,6-hexamethylenediamine), 1,4-dimethylpiperazine (1,4-dimethylpiperazine), 1,4,7-trimethyl-1,4,7-triazacyclononane (1,4, 7-triazacylcyclononane), 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (1,4,8,11-tetramethyl-1,4,8,11-tetraazacylcotetradecane), N,N,N',N'-tetramethyl-1,4-phenylenediamine (N,N,N',N'-tetramethyl-1,4-phenylenediamine), N,N,N',N'-tetramethyl-1,3-phenylenediamine (N,N,N',N'-tetramethyl-1,3-phenylenediamine), 1,4-bis(diphenylamino)benzene, 4,4'-trimethylenebis(1-methylpiperidine) (4,4'-hexamine), altretamine, and polyethyleneimine.

10. The solvent of the first solution is water, methanol, ethanol, propanol, butanol, isopropanol, ethyl acetate, acetone, chloroform, tetrahydrofuran, dimethyl sulfoxide, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, 2. The method for producing a thin film composite separator for alkaline water electrolysis according to claim 1, wherein at least one selected from the group consisting of N-methyl-2-pyrrolidone, dimethylformamide, N-methyl-2-pyrrolidone, acetophenone, and acetonitrile is used.

11. Alkyl halide monomers include 1,2-dichloroethane, 1,3-dichloropropane, 1,3-dibromopropane, 1,4-dichlorobutane, 1,4-dibromobutane, 1,4-dibromobutane, 1,4-diiodobutane, 1,6-dichlorohexane, 1,2-bis(bromomethyl)benzene, and 1,3-bis(bromomethyl)benzene.

2. The method for producing a thin film composite separation membrane for alkaline water electrolysis according to claim 1, wherein the aryl group is at least one selected from the group consisting of 1,3-bis(bromomethyl)benzene, 1,4-bis(bromomethyl)benzene, 1,3,5-tris(bromomethyl)benzene, 2,6-bis(bromomethyl)naphthalene, and 1,4-bis(1,2-dibromoethyl)benzene.

12. The solvent of the second solution is n-hexane, pentane, cyclohexane, heptane, octane, decane, dodecane, carbon tetrachloride, benzene, xylene, toluene, chloroform, tetrahydrofuran, N-methyl-2-pyrrolidone, acetophenone, acetonitrile, dimethyl phthalate, 2. The method for producing a thin film composite separator for alkaline water electrolysis according to claim 1, wherein the organic solvent is at least one selected from the group consisting of diethyl phthalate, diethyl phthalate, dibutyl phthalate, dimethylformamide, and isoparaffin.

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