Gas diffusion layer for anion exchange membrane water electrolysis and method for manufacturing same

Abstract

The present invention provides a gas diffusion layer for anion exchange membrane water electrolysis that is hydrophilic and has alkali resistance while maintaining high porosity and low electrical resistance, and a method for producing the same.

Description

[Technical Field]

[0001] Cross-Citation of Related Applications This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0169323 dated November 30, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a gas diffusion layer for anion exchange membrane water electrolysis and a method for producing the same. [Background technology]

[0003] The gas diffusion layer (GDL) is a key component in fuel cells (FC) and electrolysis (EC) that transports reactants to electrodes and discharges products, as well as dissipating heat and supporting electrodes.

[0004] Most commercial GDLs are used in polymer electrolyte membrane fuel cells (PEMFCs) and have a structure in which a microporous layer (MPL) containing a hydrophobic polymer is coated on porous carbon paper. In fuel cells, water generated from the cathode can block the pores of the gas diffusion layer (a phenomenon known as water flooding), so the gas diffusion layer must be hydrophobic. Therefore, the gas diffusion layer of fuel cells uses PTFE as a polymer and a binder to impart hydrophobicity.

[0005] However, unlike fuel cells, anion exchange membrane water electrolysis requires smooth electrolyte movement, making hydrophobic gas diffusion layers unsuitable. In other words, improved wettability with the electrolyte is essential for mass transport, and the more hydrophilic the gas diffusion layer, the more advantageous it is. Furthermore, because a highly concentrated KOH aqueous solution is used as the electrolyte, the gas diffusion layer should have high alkali resistance.

[0006] Therefore, there is a need to develop a gas diffusion layer that is hydrophilic and highly alkali-resistant and can be used in anion exchange membrane water electrolysis. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention provides a gas diffusion layer for anion exchange membrane water electrolysis and a method for producing the same.

[0008] Specifically, the present invention provides a gas diffusion layer for anion exchange membrane water electrolysis that is hydrophilic and alkali resistant while maintaining high porosity and low electrical resistance, and a method for manufacturing the same. [Means for solving the problem]

[0009] A gas diffusion layer for anion exchange membrane water electrolysis according to one embodiment of the present invention includes a porous support and a polymer thin film deposited on all or part of the surface of the porous support, and the polymer thin film may include one or more functional groups selected from the group consisting of amine, hydroxyl, ester, anhydride, carboxyl, epoxy, and pyridine.

[0010] In addition, a method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis according to one embodiment of the present invention may include the steps of: preparing a porous support (Step 1); and forming a polymer thin film deposited on all or part of the surface of the porous support using initiated chemical vapor deposition (iCVD) (Step 2). [Effects of the Invention]

[0011] The present invention can provide a gas diffusion layer for anion exchange membrane water electrolysis that is hydrophilic and has high alkali resistance.

[0012] Furthermore, the present invention can provide a gas diffusion layer for anion exchange membrane water electrolysis that maintains high porosity and low electrical resistance.

[0013] The present invention also provides a method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis using initiated chemical vapor deposition.

[0014] Furthermore, the present invention makes it possible to effectively modify the surface of the entire porous support at a very thin thickness by using an initiated chemical vapor deposition method for manufacturing the support. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram of a gas diffusion layer for anion exchange membrane water electrolysis according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram of a gas diffusion layer for anion exchange membrane water electrolysis according to an embodiment of the present invention. [Figure 3] 1 shows scanning electron microscope (SEM) images of the surface of a porous support before and after deposition of a polymer thin film according to an embodiment of the present invention. [Figure 4] 1 shows the results of observation using a contact angle analyzer (DSA, KRUSS) to measure the contact angle of the carbon paper of the present invention and a comparative example. [Figure 5]1 shows the results of observation using a contact angle analyzer (DSA, KRUSS) to measure the contact angle of a gas diffusion layer having a microporous layer formed on one surface of carbon paper according to a comparative example of the present invention. [Figure 6] 1 shows an observation result using a contact angle analyzer (DSA, KRUSS) to measure the contact angle of a gas diffusion layer in which a polymer thin film is formed on one surface of carbon paper according to an embodiment of the present invention. [Figure 7] 1 shows the results of observation using a contact angle analyzer (DSA, KRUSS) to measure the contact angle of a gas diffusion layer in which a microporous layer is formed on one surface of carbon paper and a polymer thin film is formed thereon according to an embodiment of the present invention. [Figure 8] 10 is a graph showing FT-IR measurements of a gas diffusion layer having a polymer thin film formed on an entire surface of carbon paper according to an embodiment of the present invention before and after an alkali resistance test. [Figure 9] 1 shows the results of measuring the average electrical resistance value depending on the compression ratio in an experimental example of the present invention. [Figure 10] 1 shows the results of measuring the average electrical resistance value depending on the compression ratio in an experimental example of the present invention. [Figure 11] 1 shows the results of measuring the average electrical resistance value depending on the compression ratio in an experimental example of the present invention. [Figure 12] 1 shows the results of measuring the average electrical resistance value depending on the compression ratio in an experimental example of the present invention. [Figure 13] 1 shows the results of measuring the gas permeability of an experimental example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] In the present invention, terms such as "first" and "second" are used to describe various components, and the terms are used only to distinguish one component from another.

[0017] Furthermore, the terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly dictates otherwise. In this specification, terms such as "comprises," "has," or "has" are intended to specify the presence of embodied features, numbers, steps, components, or combinations thereof, and should be understood not to preclude the presence or additional possibility of one or more other features, numbers, steps, components, or combinations thereof.

[0018] Furthermore, in this specification, when a layer or element is referred to as being formed "on" or "on" another layer or element, it means that the layer or element is formed directly on the other layer or element, or that other layers or elements can be additionally formed between the layers, on the object, or on the substrate.

[0019] While the present invention can be modified in various ways and can take various forms, the following detailed description will be given by way of example of a specific embodiment, but it should be understood that the present invention is not intended to be limited to the specific disclosed form, and that the present invention encompasses all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0020] In anion exchange membrane water electrolysis, increasing the hydrophilicity of the gas diffusion layer increases the wettability and permeability of the electrolyte, thereby increasing cell efficiency. Therefore, existing gas diffusion layers for fuel cells, which have hydrophobic microporous layers, reduce the wettability of the electrolyte. Furthermore, the thickness of the microporous layer, which can reach several tens of micrometers (μm), can also reduce the porosity of the porous support of the gas diffusion layer. Therefore, hydrophilic surface modification of the porous support through a thin, nanometer-scale polymer thin film is required. Furthermore, in the case of anion exchange membrane water electrolysis, a highly concentrated KOH aqueous solution is used as the electrolyte in water electrolysis processes, so the polymer thin film must be both hydrophilic and highly alkali-resistant.

[0021] The gas diffusion layer for anion exchange membrane water electrolysis of the present invention will now be specifically described.

[0022] The present invention provides a gas diffusion layer for anion exchange membrane water electrolysis that is hydrophilic and has high alkali resistance while maintaining high porosity and low electrical resistance.

[0023] FIG. 1 is a schematic diagram of a gas diffusion layer for anion exchange membrane water electrolysis according to one embodiment of the present invention.

[0024] 1, the present invention provides a gas diffusion layer 100 for anion exchange membrane water electrolysis, comprising a porous support 10 and a polymer thin film 20 deposited on all or part of the surface of the porous support, the polymer thin film containing one or more functional groups selected from the group consisting of amine, hydroxyl, ester, anhydride, carboxyl, epoxy, and pyridine. The functional groups contained in the polymer thin film 20 can impart hydrophilic properties to the polymer thin film while also imparting high alkali resistance.

[0025] The polymer thin film 20 may have a thickness of 10 to 200 nm. Specifically, the polymer thin film may have a thickness of 10 nm or more, 25 nm or more, 50 nm or more, 75 nm or more, or 100 nm or more, and may have a thickness of 200 nm or less, 175 nm or less, 150 nm or less, or 125 nm or less.

[0026] The polymer thin film 20 may include one or more repeating units selected from the group consisting of vinylpyridine, hydroxyalkyl (meth)acrylate, dimethylaminoalkyl (meth)acrylate, dimethylaminoalkyl styrene, ethylene glycol (meth)acrylate, ethylene glycol di(meth)acrylate, styrene-co-maleic anhydride, and (meth)acrylic acid-based monomers. Specifically, the polymer thin film 20 may include the following repeating units:

[0027] [ka]

[0028] Among these, 2-vinylpyridine or 4-vinylpyridine can be preferably used as the monomer. Pyridine-based monomers have a high pKa and therefore exhibit excellent alkali resistance.

[0029] By including the repeating units, the polymer thin film 20 has one or more functional groups selected from the group consisting of amine, hydroxyl, ester, anhydride, carboxyl, epoxy, and pyridine, and thus exhibits hydrophilicity.

[0030] The gas diffusion layer 100 for anion exchange membrane water electrolysis may have a contact angle of 50° or less. Since the gas diffusion layer 100 of the present invention is hydrophilic, it is preferable not to set a lower limit for the water contact angle, and specifically, the contact angle may be 40° or less, 30° or less, 20° or less, 10° or less, or 0°.

[0031] The contact angle can be measured by dropping a drop (10 μL) of distilled water on the surface of the gas diffusion layer before and after modification, photographing it with a contact angle analyzer (DSA, KRUSS), and measuring the contact angle. The contact angle measurement method was in accordance with Korean Patent No. 1644025.

[0032] The gas diffusion layer 100 for anion exchange membrane water electrolysis has a gas permeability of 1×10 -12 m 2 The higher the gas permeability of the gas diffusion layer 100 for anion exchange membrane water electrolysis of the present invention, the better the product, so it is preferable not to set an upper limit. 2 That's it, 5 x 10 -12 m 2 That's it, 10 x 10 -12 m 2 That's it, 30 x 10 -12 m 2 That's it, 40 x 10 -12 m 2 That's it, 50 x 10 -12 m 2 or more, or 60 x 10 -12 m 2 That's 80 x 10 -12 m 2 Below, 70 x 10 -12 m 2 or less, or 65 x 10 -12 m 2 It may be the following:

[0033] The gas permeability of the present invention was measured using a GDL basic property evaluation device (CPRT 10, Korea Institute of Energy Technology's own standard) at random over an area of ​​0.332 cm 2 The GDL surface is contacted and measured three times in total, and the gas permeability can be calculated using the following paper and Equation 1.

[0034] The gas permeability was calculated using the through-plane permeability method described in the paper "In-plane and through-plane gas permeability of carbon ber electrode backing layers (Jeff T. Gostick, et al., Sep 1 2006)" and calculated using the following formula (1): 2 ) was calculated.

[0035]

number

[0036] In the above formula 1, K is the gas permeability (m 2 ), μ is the dynamic viscosity of the gas used, A is the cross-sectional area through which the gas permeates, t is the thickness of the gas diffusion layer through which the gas permeates, m is the flow rate (mass) of the gas flowing through a unit area, P1 is the pressure before the gas permeates, P2 is the pressure after the gas permeates, R is the gas constant, T is the temperature, M is the weight of the gas used, and P avg means the average value of P1 and P2.

[0037] The gas diffusion layer 100 for anion exchange membrane water electrolysis may be alkali resistant in a 1 M KOH aqueous solution. Specifically, the gas diffusion layer 100 for anion exchange membrane water electrolysis of the present invention does not lose its hydrophilicity and does not decompose or peel off even after being stored in 1 M KOH for 3 days.

[0038] The porous support 10 included in the gas diffusion layer 100 for anion exchange membrane water electrolysis of the present invention is not limited as long as it is a porous material, and may be, for example, porous carbon in the form of cloth, felt, or paper, or nickel or titanium in the form of a mesh. Specifically, it may be porous carbon paper. The porous support may have a thickness of 100 to 500 μm.

[0039] FIG. 2 is a schematic diagram of a gas diffusion layer for anion exchange membrane water electrolysis according to another embodiment of the present invention.

[0040] 2, the gas diffusion layer 100 for anion exchange membrane water electrolysis may further include a microporous layer 30 containing polytetrafluoroethylene (PTFE) between the porous support 10 and the polymer thin film 20. The microporous layer 30 containing polytetrafluoroethylene (PTFE) may have a thickness of 50 to 200 μm.

[0041] The present invention also provides a method for producing the gas diffusion layer for anion exchange membrane water electrolysis.

[0042] The method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis according to the present invention may include the steps of: preparing a porous support (Step 1); and forming a polymer thin film deposited on all or part of the surface of the porous support using initiated chemical vapor deposition (iCVD) (Step 2).

[0043] The porous support in step 1 is not limited as long as it is a porous material, and may be, for example, one or more of the group consisting of porous carbon cloth, porous carbon felt, porous carbon paper, nickel mesh, titanium mesh, etc. Specifically, it may be porous carbon paper.

[0044] The initiated chemical vapor deposition (iCVD) method used in step 2 is a process for depositing nanoscale polymer thin films on various types of substrates in a gas phase. This method allows for uniform deposition of thin films, enabling surface modification of the substrate (i.e., the gas diffusion layer) without affecting its porosity or electrical resistance. In particular, the present invention aims to provide a method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis through surface modification of a porous support, regardless of whether a microporous layer is present, by depositing a hydrophilic polymer thin film with high alkali resistance on a porous support using initiated chemical vapor deposition.

[0045] Specifically, iCVD is a method of polymerizing monomers by decomposing a gaseous initiator into radicals. Peroxides such as tert-butyl peroxide are commonly used as initiators. These are volatile substances with a boiling point of around 110°C and undergo thermal decomposition at around 150°C. In addition to initiators such as peroxides that decompose when exposed to heat to form radicals, benzophenone, which decomposes when exposed to UV and light to form radicals, can also be used as the initiator.

[0046] In the iCVD process, thin film deposition occurs using energy supplied by a heated filament heat source or UV light. In particular, the iCVD process is carried out at a low filament temperature between 180°C and 350°C, allowing the temperature of the substrate surface on which the polymer thin film is deposited to be maintained at a low temperature of 10°C to 50°C. This has the advantage of preventing defects such as thermal shrinkage that can occur in the porous support prepared in the previous step (Step 1) due to the high-temperature process. At the same time, the process is carried out in a vacuum state with a chamber pressure of between 0.01 and 1 Torr, eliminating the need for high-vacuum equipment, and the flow rates of the monomer and initiator can be adjusted using injection valves.

[0047] In the step 2, a monomer containing one or more functional groups selected from the group consisting of amine, hydroxyl, ester, anhydride, carboxyl, epoxy, and pyridine can be used as the monomer for the polymer thin film.

[0048] Specifically, the monomer may include a pyridine-based vinyl or acrylate monomer, a hydroxyalkyl-based acrylate monomer, a tertiary amine-based monomer, and the like.

[0049] For example, the polymerizable monomer may include repeating units derived from one or more monomers selected from the group consisting of vinylpyridine, hydroxyalkyl (meth)acrylate, dimethylaminoalkyl (meth)acrylate, dimethylaminoalkyl styrene, ethylene glycol (meth)acrylate, ethylene glycol di(meth)acrylate, styrene-co-maleic anhydride, and (meth)acrylic acid-based monomers.

[0050] In addition, in the step 2, tert-butyl peroxide, tert-butyl peroxybenzoate, etc. can be used as an initiator for initiated chemical vapor deposition (iCVD).

[0051] The above (Step 2) can be performed at a reactor chamber pressure of 0.01 Torr to 1 Torr. Specifically, the reactor chamber pressure may be 0.01 Torr or more, 0.1 Torr or more, 0.2 Torr or more, or 0.3 Torr or more, and 1 Torr or less, 0.8 Torr or less, 0.6 Torr or less, or 0.4 Torr or less. If the reactor chamber pressure is too low or too high, deposition of the polymer thin film on the porous support may not occur or the deposition rate may be slow.

[0052] The above (Step 2) can be performed at a substrate temperature in the reactor of 10 to 50° C. Specifically, the substrate temperature in the reactor can be 10° C. or higher, 20° C. or higher, or 30° C. or higher, and 50° C. or lower, or 40° C. If the substrate temperature is less than 10° C., the deposition uniformity of the polymer thin film may decrease, and if it exceeds 50° C., the deposition rate may slow down.

[0053] In the step 2, the monomer flow rate in the reactor may be 1 sccm to 10 sccm. Specifically, the monomer flow rate may be 1 sccm or more, or 2 sccm or more, and 10 sccm or less, 5 sccm or less, or 4 sccm or less.

[0054] In addition, in the step 2, the initiator flow rate in the reactor may be 1 sccm to 5 sccm. Specifically, the initiator flow rate may be 1 sccm or more and 5 sccm or less, 3 sccm or less, or 2 sccm or less.

[0055] If the monomer flow rate or initiator flow rate is too low or too high, the deposition thickness may be too thin or too thick even if the deposition time is sufficient.

[0056] The polymer thin film deposition (Step 2) can be performed on one or both sides of the porous support. When it is performed on both sides, the iCVD process can be repeated under the above conditions.

[0057] The polymer thin film deposited to cover all or at least a portion of the surface of the porous support by the above-described manufacturing method is not formed as a sheet-shaped thin film on the porous support, but is deposited in a form that maintains the pore structure of the porous support, thereby maintaining the porous nature of the porous support.

[0058] Preferred examples are presented below to aid in understanding the invention, but the following examples are merely for the purpose of illustrating the invention and are not intended to limit the invention thereto. [Example]

[0059] Example 1 Porous carbon paper (JNT20, JNTG) was prepared as the porous support. Then, 4-vinylpyridine (4-VP) (Aldrich, 95% purity) was placed in the storage tube of an iCVD reactor (Daeki Hitech, iCVD system (custom built)) as the polymer thin film monomer and heated to 45°C. Then, tert-butyl peroxide (Aldrich, 98% purity) was placed in the initiator tube and maintained at room temperature. The initiator tert-butyl peroxide and the monomer 4-vinylpyridine (4-VP) were flowed at a flow rate of 1.172 sccm and 3.515 sccm, respectively. The porous carbon paper was loaded into the reactor, and the temperature of the substrate inside the reactor was maintained at 30°C. The filament temperature was set to 140°C and the pressure was set to 0.3 Torr, and initiated chemical vapor deposition was performed on only one side of the porous support for 30 minutes to obtain a gas diffusion layer in which a polymer thin film of 50 nm was formed on the entire surface of the porous carbon paper.

[0060] <Example 2> We prepared porous carbon paper (JNTG, JNT20-A6H) with a microporous layer containing PTFE formed on one side. JNT20-A6H has a thickness of 250 ± 20 μm, can be operated under high humidity conditions, and has an electrical resistance of 10 mOhm cm. 2 and the density is 100±10g / m 2 is.

[0061] Thereafter, a polymer thin film was formed on the PTFE-containing microporous layer in the same manner and at the same flow rate as in Example 1 to obtain a gas diffusion layer.

[0062] Example 3 A multi-layered GDL (JNT20-A3) was prepared by coating porous carbon paper (JNT20) with a microporous layer containing PTFE to increase hydrophobicity and reduce porosity. JNT20-A3 has a thickness of 250 ± 20 μm, can be operated under high humidity conditions, and has an electrical resistance of 15 mOhm cm. 2 and density is 95±10g / m 2 is.

[0063] Thereafter, a polymer thin film was formed in the same manner and at the same flow rate as in Example 1 to obtain a gas diffusion layer.

[0064] Example 4 A multi-layered GDL (JNT20-A6L) was prepared by coating porous carbon paper (JNT20) with a microporous layer containing PTFE to increase hydrophobicity and reduce porosity. JNT20-A6L has a thickness of 250 ± 20 μm, can be operated under low humidity conditions, and has an electrical resistance of 10 mOhm cm. 2 and density is 95±10g / m 2 is.

[0065] Thereafter, a polymer thin film was formed in the same manner and at the same flow rate as in Example 1 to obtain a gas diffusion layer.

[0066] <Comparative Example 1> As Comparative Example 1, clean porous carbon paper without a microporous layer or a thin polymer film was prepared.

[0067] <Comparative Example 2> As Comparative Example 2, porous carbon paper (JNTG, JNT20-A6H) having a PTFE-containing microporous layer formed on one surface was prepared.

[0068] <Comparative Example 3> As Comparative Example 3, porous carbon paper (JNTG, JNT20-A3) having a PTFE-containing microporous layer formed on one surface was prepared.

[0069] <Comparative Example 4> As Comparative Example 4, porous carbon paper (JNTG, JNT20-A6L & A6H) having a PTFE-containing microporous layer formed on one surface was prepared.

[0070] <Experimental Example 1 - Observation of porous support surface before and after polymer thin film deposition> The surfaces of Example 1 and Comparative Example 1 were observed by SEM, and the results are shown in FIG. It was confirmed that there was no change observed between the surface of Comparative Example 1 and the surface of Example 1, and in particular, there was no change in porosity.

[0071] <Experimental Example 2 - Contact angle measurement> The contact angles of the gas diffusion layers of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 were measured. The contact angles were measured using a contact angle analyzer (DSA, KRUSS) after placing a drop of distilled water (10 μl) on the surface of the gas diffusion layer before and after modification.

[0072] As a result, in Example 1, it was confirmed that the surface was modified to be superhydrophilic with a contact angle of 0° (Figure 6). In Example 2, even though a PTFE microporous layer was included as an intermediate layer, the contact angle was measured at 40°, indicating that the surface still exhibited hydrophilicity (Figure 7).

[0073] On the other hand, the contact angle was 128° (FIG. 4) in Comparative Example 1 and 156° (FIG. 5) in Comparative Example 2, indicating that both exhibited hydrophobicity.

[0074] From these results, it was found that the gas diffusion layer including the polymer thin film according to the present invention has a well-modified hydrophilic surface and is suitable for use in anion exchange membrane water electrolysis.

[0075] <Experimental Example 3 - Alkali resistance test> The gas diffusion layer on which the polymer thin film of Example 1 was formed was tested for alkali resistance.

[0076] The gas diffusion layer of Example 1 was immersed in a 1 M KOH aqueous solution for 3 days to simulate the environment during use in anion exchange membrane water electrolysis, and then the contact angle and FT-IR peak change were measured.

[0077] The contact angle was measured in the same manner as in Experimental Example 2, and both before and after the alkali resistance test, the contact angle was measured to be 0°, confirming that the surface still had superhydrophilic properties.

[0078] FT-IR was measured before and after the alkali resistance test using an FT-IR spectrometer (ALPHA FT-IR Spectrometer, BRUKER), and the resulting peaks are shown in Figure 8. The peaks at 1415 cm were the same before and after the alkali resistance test. -1 , 1596cm -1 A pyridine peak was detected, confirming that no change in the composition of the polymer thin film occurred.

[0079] In conclusion, it was found that the gas diffusion layer of the present invention maintains sufficient wettability without the polymer thin film disappearing or changing in composition even when used in anion exchange membrane water electrolysis under strongly alkaline conditions.

[0080] <Experimental Example 4 - Observation of average electrical resistance depending on compression ratio> The electrical resistance was observed as a function of the compression ratio for each set of Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, and Example 4 and Comparative Example 4. A comparison between Example 1 and Comparative Example 1 is shown in FIG. 9, a comparison between Example 2 and Comparative Example 2 is shown in FIG. 10, a comparison between Example 3 and Comparative Example 3 is shown in FIG. 11, and a comparison between Example 4 and Comparative Example 4 is shown in FIG. 12. All data are shown in Table 1 below.

[0081] In the present invention, the electrical resistance according to the compressibility was measured by randomly measuring the area of ​​4.799 cm using a GDL basic physical property evaluation device (CPRT 10, Korea Institute of Energy Technology). 2 The GDL surface was contacted and measurements were carried out three times in total, with the pressure ranging from 0.25 to 10 kgf / cm 2 The compression ratio range was

[0082] As shown in Figures 9 to 12, in Examples 1 to 4 in which a polymer thin film was deposited, electrical resistance increased slightly at all compression ratios. However, this increase was so small that it did not affect the use of the membrane for anion exchange membrane water electrolysis. In particular, when the compression ratio, which is the environment in which the water electrolysis cell is assembled, was increased, there was almost no difference, demonstrating that the membrane is suitable for use in anion exchange membrane water electrolysis.

[0083] [Table 1]

[0084] <Experimental Example 5 - Gas Permeability Observation> The gas permeabilities of Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, and Example 4 and Comparative Example 4 were observed, and the results are shown in FIG.

[0085] The gas permeability of the present invention was measured using a GDL basic property evaluation device (CPRT 10, Korea Institute of Energy Technology's own standard) at random over an area of ​​0.332 cm 2 The GDL surface was contacted and measured three times in total, and the gas permeability was calculated using the following paper and Equation 1.

[0086] The gas permeability was calculated using the through-plane permeability method in Fig. 2 of the paper "In-plane and through-plane gas permeability of carbon ber electrode backing layers (Jeff T. Gostick, et al., Sep 1 2006)" and calculated using the following formula (1): 2 ) was calculated.

[0087]

number

[0088] In the above formula 1, K is the gas permeability, μ is the dynamic viscosity of the gas used, A is the cross-sectional area through which the gas permeates, t is the thickness of the gas diffusion layer through which the gas permeates, m is the flow rate (mass) of the gas flowing through a unit area, P1 is the pressure before the gas permeates, P2 is the pressure after the gas permeates, R is the gas constant, T is the temperature, M is the molecular weight of the gas used, and P avg means the average value of P1 and P2.

[0089] As shown in FIG. 13, it was confirmed that there was no difference in gas permeability before and after the polymer thin film deposition.

[0090] [Table 2] [Explanation of symbols]

[0091] 100 Gas diffusion layer 10 Porous support 20 Polymer thin film 30 Microporous layer

Claims

1. a porous support; and a thin polymer film deposited on all or part of the surface of the porous support; The polymer thin film comprises a repeating unit derived from a vinylpyridine monomer, and the polymer thin film comprises a gas diffusion layer for anion exchange membrane water electrolysis.

2. 2. The gas diffusion layer for anion exchange membrane water electrolysis according to claim 1, wherein the gas diffusion layer for anion exchange membrane water electrolysis has a contact angle with water of 50° or less.

3. The gas diffusion layer for anion exchange membrane water electrolysis has a gas permeability of 1×10 －１２ m ２ The gas diffusion layer for anion exchange membrane water electrolysis according to claim 1 .

4. The gas diffusion layer for anion exchange membrane water electrolysis according to claim 1 , which has alkali resistance in a 1 M aqueous solution of KOH.

5. 2. The gas diffusion layer for anion exchange membrane water electrolysis according to claim 1, wherein the porous support is at least one selected from the group consisting of porous carbon cloth, porous carbon felt, porous carbon paper, nickel mesh, and titanium mesh.

6. The gas diffusion layer for anion exchange membrane water electrolysis according to claim 1 , further comprising a microporous layer containing polytetrafluoroethylene between the porous support and the polymer thin film.

7. The method includes the steps of: preparing a porous support (Step 1); and forming a polymer thin film deposited on all or part of the surface of the porous support using an initiation chemical vapor deposition method (Step 2); The step 2 is a step of using a monomer containing vinylpyridine as a monomer for the polymer thin film, in a method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis.

8. 8. The method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis according to claim 7, wherein (Step 2) uses at least one selected from the group consisting of tert-butyl peroxide and tert-butyl peroxybenzoate as an initiator for initiated chemical vapor deposition.

9. 8. The method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis according to claim 7, wherein the step 2 is carried out under a pressure of 0.01 to 1 Torr in the reactor chamber.

10. 8. The method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis according to claim 7, wherein the step 2 is performed at a substrate temperature in a reactor of 10 to 50°C.

11. 8. The method of claim 7, wherein in step 2, the monomer flow rate in the reactor is 1 sccm to 10 sccm.

12. 8. The method for manufacturing a gas diffusion layer for anion exchange membrane water electrolysis according to claim 7, wherein in step 2, the flow rate of the initiator in the reactor is 1 sccm to 5 sccm.

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