Anion exchange membrane and manufacturing method thereof

Abstract

According to an embodiment of the present invention, provided are: an anion exchange membrane comprising a carbazole-based polymer, the polymer having reduced splitting characteristics; and a manufacturing method thereof.

Description

Anion exchange membrane and method for manufacturing the same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0144082, filed October 25, 2023, the entire disclosure of which is incorporated herein by reference.

[0003]

[0004] The present invention relates to an anion exchange membrane and a method for manufacturing the same. Specifically, the present invention relates to an anion exchange membrane comprising a carbazole polymer and a method for manufacturing the same.

[0005] The importance of technologies that can produce and utilize hydrogen, a next-generation energy source that can solve fossil fuel depletion and environmental pollution, in an environmentally friendly manner is being highlighted.

[0006] The structure of the membrane electrode assembly (MEA) for anion exchange membrane fuel cells and water electrolysis is composed of an anode electrode and a cathode electrode joined together around an anion exchange membrane.

[0007] Specifically, the water electrolysis MEA includes an anion exchange membrane, an anode electrode formed on one side of the anion exchange membrane, and a cathode electrode formed on the other side of the anion exchange membrane. A PTL (Porous Transport Layer) and a separator are laminated at both ends of the MEA to form a unit stack, and a plurality of unit cells form a water electrolysis stack. At the cathode electrode, water is decomposed to generate hydrogen and hydroxide ions, and at the anode electrode, oxygen is generated from the hydroxide ions. Each reaction occurs in the catalyst of the catalyst layer (CL). At this time, the anion exchange membrane (AEM) decomposes the OH generated at the cathode. - It acts to move ions to the anode electrode and prevent oxygen and hydrogen gases from moving.

[0008] In particular, according to the hydrogen economy revitalization roadmap recently announced by the Ministry of Trade, Industry and Energy, a significant portion of hydrogen production is expected to be done through eco-friendly methods, making the development of water electrolysis, a representative technology for eco-friendly hydrogen production, even more urgent.

[0009] In this regard, research on water electrolysis technology using electrolysis is actively being conducted, and the known water electrolysis technologies include cation exchange membrane water electrolysis (PEMWE), alkaline water electrolysis (AWE), and anion exchange membrane water electrolysis (AEMWE).

[0010] Dual anion exchange membrane electrolysis is a water electrolysis system that utilizes the advantages of existing cation exchange membrane electrolysis and alkaline electrolysis while overcoming their disadvantages.

[0011] The carbazole polymer intended for use as an anion exchange material in this anion exchange membrane electrolysis has excellent alkalinity and high conductivity, making it suitable as an anion exchange material. However, its cracking and brittle properties pose difficulties for practical use. In particular, the manufacturing process of the membrane electrode assembly involves repeated high-temperature and high-pressure conditions, which can cause the anion exchange membrane containing the carbazole polymer to crack or break during the process.

[0012]

[0013] Accordingly, the present invention aims to provide an anion exchange membrane including a carbazole polymer, wherein the polymer's cracking characteristics are alleviated, and a method for manufacturing the same.

[0014]

[0015] An anion exchange membrane of one embodiment of the present invention comprises a first carbazole-based polymer layer; a porous support layer; and a second carbazole-based polymer layer, wherein the porous support layer is provided between the first carbazole-based polymer layer and the second carbazole-based polymer layer, and the total thickness of the first carbazole-based polymer layer, the porous support layer, and the second carbazole-based polymer layer may be greater than 40 μm and less than 150 μm.

[0016] The method may include the steps of: coating a first carbazole-based polymer composition on a release paper (step 1); positioning a porous support on the first carbazole-based polymer composition layer to obtain a first composite membrane (step 2); drying the first composite membrane (step 3); coating a second carbazole-based polymer composition on the porous support of the dried first composite membrane to obtain a second composite membrane (step 4); drying the second composite membrane (step 5); and removing the release paper (step 6).

[0017]

[0018] According to one embodiment of the present invention, an anion exchange membrane including a carbazole-based polymer, but with alleviated cracking characteristics of the polymer, and a method for manufacturing the same can be provided.

[0019]

[0020] Figure 1 is a schematic diagram of an anion exchange membrane according to one embodiment of the present invention.

[0021] Figure 2 is a photograph of a cross-section of a 58 ㎛ thick single film of a comparative example of the present invention taken using a scanning electron microscope (SEM).

[0022] Figure 3 is a photograph of a cross-section of a reinforced film having a thickness of 80.6 ㎛ of an example, taken using a scanning electron microscope (SEM).

[0023] Figure 4 is a photograph of a reinforcing film manufactured in a roll type according to the present invention.

[0024] Figure 5 is a photograph confirming the breakability of an anion exchange membrane manufactured in an experimental example of the present invention.

[0025] Figure 6 shows the results of evaluating the performance of a water electrolysis system after manufacturing an MEA using a reinforced composite membrane manufactured according to the present invention.

[0026]

[0027] In the present invention, terms such as first, second, etc. are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another.

[0028] Furthermore, the terminology used herein is merely for the purpose of describing exemplary embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprise," "include," or "have" indicate the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0029] Additionally, in the present invention, when each layer or element is referred to as being formed “on” or “over” each layer or element, it means that each layer or element is formed directly on each layer or element, or that other layers or elements may be additionally formed between each layer, on the object, or on the substrate.

[0030] The present invention is susceptible to various modifications and takes various forms. Specific embodiments are illustrated and described in detail below. However, this is not intended to limit the present invention to specific disclosed forms, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0031]

[0032] Carbazole polymers have excellent alkaline resistance and high conductivity, making them suitable as anion exchange membrane materials. However, carbazole polymers have a tendency to crack, making them difficult to use as anion exchange membranes. In particular, the high-temperature process of manufacturing membrane electrode assemblies can cause anion exchange membranes containing carbazole polymers to crack or break.

[0033] Accordingly, the inventors of the present invention intend to provide an anion exchange membrane including a carbazole polymer but with improved splitting characteristics in order to utilize the excellent anion exchange properties of a carbazole polymer.

[0034]

[0035] Hereinafter, the anion exchange membrane including the carbazole polymer of the present invention will be examined in detail.

[0036]

[0037] An anion exchange membrane (100) of one embodiment of the present invention may include a first carbazole-based polymer layer (1); a porous support layer (2); and a second carbazole-based polymer layer (3). In addition, the porous support layer may be provided between the first carbazole-based polymer layer and the second carbazole-based polymer layer. That is, the anion exchange membrane of the present invention may be a composite membrane having a three-layer structure in which a carbazole-based polymer layer is coated on both sides of the porous support layer, with the porous support layer as the center.

[0038]

[0039] The first carbazole-based polymer and the second carbazole-based polymer may each independently include a compound represented by the following chemical formula 1:

[0040] [Chemical Formula 1]

[0041]

[0042]

[0043] In the above chemical formula 1,

[0044] R1 to R4 are each independently C 1-60 alkylene; C 6-60 Arylene; or C 2-60 It's allylene,

[0045] The above R1 to R4 may each be independently unsubstituted or substituted with one or more fluorines,

[0046] The above R1 to R4 may each independently include one or more heteroatoms selected from the group consisting of O, N, and S instead of carbon,

[0047] The above R1 to R4 may be the same or different for each repeating unit,

[0048] X1 to X4 may each independently be a hydrogen atom; or an anion exchanger,

[0049] At least one of the above X1 to X4 is an anion exchanger,

[0050] The above anion exchanger is at least one independently selected from the group consisting of an amine group, an ammonium group, an amino group, an imine group, a sulfonium group, a phosphonium group, a pyridyl group, a carbazolyl group, an imidazolyl group, or a salt thereof,

[0051] m or n are each independently an integer from 1 to 100,000.

[0052] Specifically, the compound represented by Chemical Formula 1 may be poly(9-(6-(trimethylammonium bromide)hexyl)-9H-carbazole-co-1,1,1-trifluoroisopropane) represented by Chemical Formula 2 below.

[0053] [Chemical Formula 2]

[0054]

[0055] The carbazole polymer included in the first carbazole polymer layer and the carbazole polymer included in the second carbazole polymer layer may be the same or different. Specifically, the carbazole polymer included in the first carbazole polymer layer and the carbazole polymer included in the second carbazole polymer layer may be the same polymer.

[0056]

[0057] The above porous support may include at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), and polytetrafluoroethylene (PTFE), which have excellent alkali resistance.

[0058] A porous material is used as the support, and the carbazole polymer is partially impregnated into the porous support, thereby forming OH - It can facilitate the movement of ions and prevent the breakage of the carbazole polymer by bonding the first carbazole polymer layer and the second carbazole polymer layer to the porous support.

[0059]

[0060] The anion exchange membrane may have a total thickness of the first carbazole-based polymer layer, the porous support layer, and the second carbazole-based polymer layer of greater than 40 μm and less than or equal to 170 μm. Specifically, the anion exchange membrane may have a total thickness of greater than 40 μm, greater than or equal to 60 μm, greater than or equal to 70 μm, greater than or equal to 80 μm, or greater than or equal to 100 μm, to less than or equal to 170 μm, less than or equal to 150 μm, less than or equal to 140 μm, less than or equal to 130 μm, or less than or equal to 120 μm.

[0061]

[0062] To prevent explosion-related problems during system operation, anion electrolysis systems specify a range of hydrogen content relative to oxygen at the anode electrode. The explosion potential exists when the hydrogen content exceeds 4% relative to oxygen, and the system is designed to shut down when the hydrogen content exceeds 2%.

[0063] Accordingly, if the total thickness of the anion exchange membrane is less than 40 ㎛, the hydrogen gas generated at the cathode electrode moves toward the anode electrode through the anion exchange membrane, and the hydrogen content relative to the oxygen content exceeds 2%, so there is a high possibility that the system will not operate.

[0064] On the other hand, when the total thickness of the anion exchange membrane exceeds 170 ㎛, the carbazole polymer layer becomes thick and the characteristics of the carbazole polymer become dominant, so the manufactured anion exchange membrane may crack or break due to the cracking characteristics of the carbazole polymer.

[0065]

[0066] Additionally, the first carbazole-based polymer layer may have a thickness of 5 μm to 73 μm. Specifically, the thickness may be 15 μm to 70 μm.

[0067] Additionally, the porous support layer may have a thickness of 5 μm to 50 μm. Specifically, the thickness may be 5 μm to 30 μm.

[0068] Additionally, the second carbazole-based polymer layer may have a thickness of 5 μm to 73 μm. Specifically, the thickness may be 15 μm to 70 μm.

[0069]

[0070] The anion exchange membrane in the form of a composite membrane of the present invention has improved breakage characteristics of the carbazole polymer, and can be processed into a roll shape (see Fig. 5).

[0071]

[0072] Another embodiment of the present invention provides a method for manufacturing an anion exchange membrane, comprising: a step of coating a first carbazole-based polymer composition on a release paper (step 1); a step of positioning a porous support on the first carbazole-based polymer composition layer to obtain a first composite membrane (step 2); a step of drying the first composite membrane (step 3); a step of coating a second carbazole-based polymer composition on the porous support of the dried first composite membrane to obtain a second composite membrane (step 4); a step of drying the second composite membrane (step 5); and a step of removing the release paper (step 6).

[0073]

[0074] The above step 1 is a step of coating a first carbazole-based polymer composition on a release paper.

[0075] The above first carbazole-based polymer composition may be a solution containing a carbazole-based polymer. The solvent used in the solution is not limited as long as it is a polar solvent, but preferably includes a polar aprotic solvent. For example, it may include N-methyl-2-pyrrolidone (NMP).

[0076] In addition, the first carbazole-based polymer composition may include a compound represented by the following chemical formula 1.

[0077]

[0078] [Chemical Formula 1]

[0079]

[0080] In the above chemical formula 1,

[0081] R1 to R4 are each independently C 1-60 alkylene; C 6-60 Arylene; or C 2-60 It's allylene,

[0082] The above R1 to R4 may each be independently unsubstituted or substituted with one or more fluorines,

[0083] The above R1 to R4 may each independently include one or more heteroatoms selected from the group consisting of O, N, and S instead of carbon,

[0084] The above R1 to R4 may be the same or different for each repeating unit,

[0085] X1 to X4 may each independently be a hydrogen atom; or an anion exchanger,

[0086] At least one of the above X1 to X4 is an anion exchanger,

[0087] The above anion exchanger is at least one independently selected from the group consisting of an amine group, an ammonium group, an amino group, an imine group, a sulfonium group, a phosphonium group, a pyridyl group, a carbazolyl group, an imidazolyl group, or a salt thereof,

[0088] m or n are each independently an integer from 1 to 100,000.

[0089] In addition, there is no limitation on the release paper as long as it is usable in the industry, but for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyimide (PI) can be used.

[0090] In addition, there is no limitation on the method for coating the first carbazole-based polymer composition as long as it is a general polymer coating method, but for example, comma coating, slot die coating, or glabia coating can be used.

[0091] Specifically, the compound represented by Chemical Formula 1 may be poly(9-(6-(trimethylammonium bromide)hexyl)-9H-carbazole-co-1,1,1-trifluoroisopropane) represented by Chemical Formula 2 below.

[0092] [Chemical Formula 2]

[0093]

[0094]

[0095] The above step 2 is a step of obtaining a first composite membrane by positioning a porous support on the first carbazole-based polymer composition layer formed in step 1.

[0096] That is, the first composite membrane may have a structure in which a release film, a carbazole-based polymer composition layer, and a porous support are sequentially laminated.

[0097] The above porous support may include at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), and polytetrafluoroethylene (PTFE), which have excellent alkali resistance.

[0098] A porous material is used as the support, and the carbazole polymer is partially impregnated into the porous support, thereby forming OH - It can facilitate the movement of ions and prevent the breakage of the carbazole polymer by bonding the first carbazole polymer layer and the second carbazole polymer layer to the porous support.

[0099]

[0100] The above step 3 is a step of drying the first composite membrane of step 2.

[0101] In step 3, the solvent of the first carbazole-based polymer composition layer included in the first composite membrane evaporates, and a portion of the first carbazole-based polymer can be dried while being impregnated into the porous support.

[0102] Drying in step 3 can be performed at a temperature of 40°C to 150°C. Specifically, it can be performed at a temperature of 60°C to 80°C.

[0103] If the temperature is too low, the solvent may take too long to dry, which may result in under-drying before proceeding to step 4, and the viscosity of the solution may increase, which may result in a low impregnation rate when the carbazole polymer is impregnated into the porous support. On the other hand, if the temperature is too high, the carbazole polymer may dry before being impregnated into the porous support, which may result in a low impregnation rate, or the support may shrink at high temperatures, causing wrinkles.

[0104]

[0105] Step 4 is a step of obtaining a second composite membrane by coating a second carbazole-based polymer composition on the porous support of the first composite membrane dried at high temperature.

[0106] The second carbazole-based polymer included in the second carbazole-based polymer composition coated in the above step 4 may be the same as or different from the first carbazole-based polymer of step 1, and may include a compound represented by the following chemical formula 1.

[0107] [Chemical Formula 1]

[0108]

[0109] In the above chemical formula 1,

[0110] R1 to R4 are each independently C 1-60 alkylene; C 6-60 Arylene; or C 2-60 It's allylene,

[0111] The above R1 to R4 may each be independently unsubstituted or substituted with one or more fluorines,

[0112] The above R1 to R4 may each independently include one or more heteroatoms selected from the group consisting of O, N, and S instead of carbon,

[0113] The above R1 to R4 may be the same or different for each repeating unit,

[0114] X1 to X4 may each independently be a hydrogen atom; or an anion exchanger,

[0115] At least one of the above X1 to X4 is an anion exchanger,

[0116] The above anion exchanger is at least one independently selected from the group consisting of an amine group, an ammonium group, an amino group, an imine group, a sulfonium group, a phosphonium group, a pyridyl group, a carbazolyl group, an imidazolyl group, or a salt thereof,

[0117] m or n are each independently an integer from 1 to 100,000.

[0118] The second carbazole-based polymer composition coated in the above step 4 may also be a solution, and the solvent is not limited as long as it is a polar solvent, but preferably may include a polar aprotic solvent. For example, it may include N-methyl-2-pyrrolidone (NMP).

[0119] In addition, there is no limitation on the method for coating the second carbazole-based polymer composition of step 4 as long as it is a general polymer coating method, but for example, comma coating, slot die coating, or glabia coating can be used.

[0120] Specifically, the compound represented by the above chemical formula 1 may be poly(9-(6-(trimethylammonium bromide)hexyl)-9H-carbazole-co-1,1,1-trifluoroisopropane) represented by the chemical formula 2.

[0121] [Chemical Formula 2]

[0122]

[0123]

[0124] Step 5 is a step of drying the second composite membrane obtained in step 4.

[0125] The second carbazole-based polymer composition coated in step 4 is in a solution state, and thus, like step 3, a drying step is required to bind it to the porous support. Accordingly, the solvent of the second carbazole-based polymer composition layer coated in step 4 evaporates, and a portion of the carbazole-based polymer can be dried while being impregnated into the porous support.

[0126] Drying in step 5 can be performed at a temperature of 40°C to 150°C. Specifically, it can be performed at a temperature of 60°C to 80°C.

[0127] If the temperature is too low, there may be a problem in which undried parts remain after the drying process and stick to the release paper when wound in a roll type, and if the temperature is too high, the porous support may shrink significantly due to heat, which may cause wrinkles.

[0128]

[0129] Step 6 is a step of removing the release film of Step 1 to obtain an anion exchange membrane having a structure in which a first carbazole-based polymer layer, a porous support, and a second carbazole-based polymer layer are sequentially laminated.

[0130]

[0131] The anion exchange membrane manufactured according to the above method for manufacturing an anion exchange membrane may have a total thickness of the first carbazole-based polymer layer, the porous support layer, and the second carbazole-based polymer layer of more than 40 ㎛ and less than 150 ㎛. Specifically, the anion exchange membrane manufactured according to the method for manufacturing an anion exchange membrane may have a total thickness of more than 40 ㎛, 50 ㎛ or more, 70 ㎛ or more, or 100 ㎛ or more, to less than 150 ㎛, 140 ㎛ or less, 130 ㎛ or less, or 120 ㎛ or less.

[0132] To prevent explosion-related problems during system operation, anion electrolysis systems specify a range of hydrogen content relative to oxygen at the anode electrode. The explosion potential exists when the hydrogen content exceeds 4% relative to oxygen, and the system is designed to shut down when the hydrogen content exceeds 2%.

[0133] Accordingly, if the total thickness of the anion exchange membrane is less than 40 ㎛, the hydrogen gas generated at the cathode electrode moves toward the anode electrode through the anion exchange membrane, and the hydrogen content relative to the oxygen content exceeds 2%, so there is a high possibility that the system will not operate.

[0134] On the other hand, when the total thickness of the anion exchange membrane exceeds 150 ㎛, the carbazole polymer layer becomes thick and the characteristics of the carbazole polymer become dominant, so the manufactured anion exchange membrane may crack or break due to the cracking characteristics of the carbazole polymer.

[0135]

[0136] Below, preferred embodiments are presented to aid understanding of the invention. However, the following examples are intended only to illustrate the invention and are not intended to limit the invention to these embodiments.

[0137]

[0138] Comparative Example 1 - Composite anion exchange membrane with a total thickness of 40 μm

[0139] (Step 1) As the first carbazole polymer, a polymer represented by the following chemical formula 2 was used, and N-Methyl-2-pyrrolidone (NMP) was used as a solvent. A first carbazole polymer composition having a solid content of 20 wt.% was prepared. A polyethylene naphthalate (PEN) film was prepared as a release paper. The first carbazole polymer composition was coated on one side of the release paper using a comma coating method. At this time, the coating amount of the first carbazole polymer composition was 100 μm.

[0140] The polymer represented by chemical formula 2 was poly(9-(6-(trimethylammonium bromide)hexyl)-9H-carbazole-co-1,1,1-trifluoroisopropane).

[0141] [Chemical Formula 2]

[0142]

[0143]

[0144] (Step 2) Polypropylene (PP) having a thickness of 12 μm was prepared as a porous support and positioned on the first carbazole-based polymer composition layer to obtain a first composite membrane.

[0145] (Step 3) The first composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes to evaporate the solvent of the first carbazole-based polymer composition.

[0146] (Step 4) A second carbazole-based polymer composition was coated on the porous support of the dried first composite membrane to obtain a second composite membrane. At this time, the polymer represented by the following chemical formula 2 was used as the second carbazole-based polymer, N-Methyl-2-pyrrolidone (NMP) was used as the solvent, the solid content was 20 wt.%, the coating was performed using the comma coating method, and the coating amount was 100 μm.

[0147] The polymer represented by chemical formula 2 was poly(9-(6-(trimethylammonium bromide)hexyl)-9H-carbazole-co-1,1,1-trifluoroisopropane).

[0148] [Chemical Formula 2]

[0149]

[0150] (Steps 5 to 6) The second composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes, and the release paper was removed to obtain an anion exchange membrane having a thickness of 40 μm.

[0151]

[0152] Comparative Example 2 - Single-membrane anion exchange membrane with a total thickness of 50 μm

[0153] (Step 1) A polymer represented by the above chemical formula 2 was used as a carbazole polymer, N-Methyl-2-pyrrolidone (NMP) was used as a solvent, and a carbazole polymer composition having a solid content of 20 wt.% was prepared. A polyethylene naphthalate (PEN) film was prepared as a release paper. The carbazole polymer composition was coated on one side of the release paper using the comma coating method. At this time, the coating amount of the carbazole polymer composition was 250 μm.

[0154] (Step 2) The carbazole-based membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes to obtain a 50 μm anion exchange membrane.

[0155]

[0156] Example 1 - Composite anion exchange membrane with a total thickness of 70 μm

[0157] (Step 1) As the first carbazole polymer, the polymer represented by the above chemical formula 2 was used, and N-Methyl-2-pyrrolidone (NMP) was used as the solvent. A first carbazole polymer composition having a solid content of 20 wt.% was prepared. A polyethylene naphthalate (PEN) film was prepared as the release paper. The first carbazole polymer composition was coated on one side of the release paper using the comma coating method. At this time, the coating amount of the first carbazole polymer composition was 180 μm.

[0158] (Step 2) Polypropylene (PP) having a thickness of 12 μm was prepared as a porous support and positioned on the first carbazole-based polymer composition layer to obtain a first composite membrane.

[0159] (Step 3) The first composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes to evaporate the solvent of the first carbazole-based polymer composition.

[0160] (Step 4) A second carbazole-based polymer composition was coated on the porous support of the dried first composite membrane to obtain a second composite membrane. At this time, the polymer represented by the chemical formula 2 was used as the second carbazole-based polymer, N-Methyl-2-pyrrolidone (NMP) was used as the solvent, the solid content was 20 wt.%, the coating was performed using the comma coating method, and the coating amount was 180 μm.

[0161] (Steps 5 to 6) The second composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes, and the release paper was removed to obtain an anion exchange membrane having a thickness of 70 μm.

[0162]

[0163] Example 2 - Composite anion exchange membrane with a total thickness of 150 μm

[0164] (Step 1) As the first carbazole polymer, the polymer represented by the above chemical formula 2 was used, and N-Methyl-2-pyrrolidone (NMP) was used as the solvent. A first carbazole polymer composition having a solid content of 20 wt.% was prepared. A polyethylene naphthalate (PEN) film was prepared as the release paper. The first carbazole polymer composition was coated on one side of the release paper using the comma coating method. At this time, the coating amount of the first carbazole polymer composition was 380 μm.

[0165] (Step 2) Polypropylene (PP) having a thickness of 12 μm was prepared as a porous support and positioned on the first carbazole-based polymer composition layer to obtain a first composite membrane.

[0166] (Step 3) The first composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes to evaporate the solvent of the first carbazole-based polymer composition.

[0167] (Step 4) A second carbazole-based polymer composition was coated on the porous support of the dried first composite membrane to obtain a second composite membrane. At this time, the polymer represented by the above chemical formula 2 was used as the second carbazole-based polymer, N-Methyl-2-pyrrolidone (NMP) was used as the solvent, the solid content was 20 wt.%, the coating was performed using the comma coating method, and the coating amount was 380 μm.

[0168] (Steps 5 to 6) The second composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes, and the release paper was removed to obtain an anion exchange membrane having a thickness of 150 μm.

[0169]

[0170] Example 3 - Composite anion exchange membrane with a total thickness of 170 μm

[0171] (Step 1) A polymer represented by Chemical Formula 2 was used as the first carbazole polymer, N-Methyl-2-pyrrolidone (NMP) was used as the solvent, and a first carbazole polymer composition having a solid content of 20 wt.% was prepared. A polyethylene naphthalate (PEN) film was prepared as the release paper. The first carbazole polymer composition was coated on one side of the release paper using the comma coating method. At this time, the coating amount of the first carbazole polymer composition was 420 μm.

[0172] (Step 2) Polypropylene (PP) having a thickness of 12 μm was prepared as a porous support and positioned on the first carbazole-based polymer composition layer to obtain a first composite membrane.

[0173] (Step 3) The first composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes to evaporate the solvent of the first carbazole-based polymer composition.

[0174] (Step 4) A second carbazole-based polymer composition was coated on the porous support of the dried first composite membrane to obtain a second composite membrane. At this time, the polymer represented by the above chemical formula 2 was used as the second carbazole-based polymer, N-Methyl-2-pyrrolidone (NMP) was used as the solvent, the solid content was 20 wt.%, the coating was performed using the comma coating method, and the coating amount was 420 μm.

[0175] (Steps 5 to 6) The second composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes, and the release paper was removed to obtain an anion exchange membrane having a thickness of 170 μm.

[0176]

[0177] Example 4 - Composite anion exchange membrane with a total thickness of 60 μm

[0178] (Step 1) As the first carbazole polymer, the polymer represented by the above chemical formula 2 was used, and N-Methyl-2-pyrrolidone (NMP) was used as the solvent. A first carbazole polymer composition having a solid content of 20 wt.% was prepared. A polyethylene naphthalate (PEN) film was prepared as the release paper. The first carbazole polymer composition was coated on one side of the release paper using the comma coating method. At this time, the coating amount of the first carbazole polymer composition was 150 μm.

[0179] (Step 2) Polypropylene (PP) having a thickness of 12 μm was prepared as a porous support and positioned on the first carbazole-based polymer composition layer to obtain a first composite membrane.

[0180] (Step 3) The first composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes to evaporate the solvent of the first carbazole-based polymer composition.

[0181] (Step 4) A second carbazole-based polymer composition was coated on the porous support of the dried first composite membrane to obtain a second composite membrane. At this time, the polymer represented by the above chemical formula 2 was used as the second carbazole-based polymer, N-Methyl-2-pyrrolidone (NMP) was used as the solvent, the solid content was 20 wt.%, the coating was performed using the comma coating method, and the coating amount was 150 μm.

[0182] (Steps 5 to 6) The second composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes, and the release paper was removed to obtain an anion exchange membrane having a thickness of 60 μm.

[0183]

[0184] Example 5 - Composite anion exchange membrane with a total thickness of 80 μm

[0185] (Step 1) As the first carbazole-based polymer, the polymer represented by the above chemical formula 2 was used, and N-Methyl-2-pyrrolidone (NMP) was used as the solvent. A first carbazole-based polymer composition having a solid content of 20 wt.% was prepared. A polyethylene naphthalate (PEN) film was prepared as the release paper. The first carbazole-based polymer composition was coated on one side of the release paper using the comma coating method. At this time, the coating amount of the first carbazole-based polymer composition was 200 μm.

[0186] (Step 2) Polypropylene (PP) having a thickness of 12 μm was prepared as a porous support and positioned on the first carbazole-based polymer composition layer to obtain a first composite membrane.

[0187] (Step 3) The first composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes to evaporate the solvent of the first carbazole-based polymer composition.

[0188] (Step 4) A second carbazole-based polymer composition was coated on the porous support of the dried first composite membrane to obtain a second composite membrane. At this time, the polymer represented by the above chemical formula 2 was used as the second carbazole-based polymer, N-Methyl-2-pyrrolidone (NMP) was used as the solvent, the solid content was 20 wt.%, and the coating was performed using the comma coating method, with a coating amount of 200 μm.

[0189] (Steps 5 to 6) The second composite membrane was dried at a temperature of 60°C for 20 minutes and at 80°C for 30 minutes, and the release paper was removed to obtain an anion exchange membrane having a thickness of 80 μm.

[0190]

[0191] Experimental Example 1 - Hydrogen Permeability Evaluation

[0192] The hydrogen content relative to the oxygen content of the anode electrode was measured using the anion exchange membranes manufactured in Comparative Example 1 and Examples 4 and 5, and the results are shown in the table below.

[0193]

[0194] Thickness of the reinforced membrane (㎛) Hydrogen content (%) compared to oxygen content Comparative example 1402.0 Example 4601.7 Example 5801.4

[0195] Hydrogen gas generated at the cathode moves to the anode electrode through the reinforcing film, and the thicker the reinforcing film, the less hydrogen moves.

[0196] The hydrogen content relative to oxygen must be 4% or higher to prevent explosion, and safety regulations require the system to shut down when it exceeds 2%. In other words, the hydrogen content relative to oxygen at the anode must be less than 2%.

[0197] In this experimental example, the hydrogen content relative to the oxygen content of the anode electrode was measured during operation of the anion exchange membrane electrolysis system at 1.5 A / cm2 atmospheric pressure. The hydrogen content was measured using Agilent's Gas Chromatography (GC). When the reinforced film thickness was 40 μm, the hydrogen content relative to the oxygen content was 2.0%, when the reinforced film thickness was 60 μm, the hydrogen content relative to the oxygen content was 1.7%, and when the reinforced film thickness was 80 μm, the hydrogen content relative to the oxygen content was 1.4%.

[0198]

[0199] Experimental Example 2 - SEM Observation

[0200] The cross-sections of the anion exchange membranes manufactured in Comparative Example 2 and Example 5 were observed using SEM and are shown in FIG. 3 and FIG. 4, respectively.

[0201]

[0202] Experimental Example 3 - Observation of Breakage Phenomenon

[0203] The anion exchange membranes manufactured in Examples 2, 3 and Comparative Example 2 were physically folded to check for breakage, as shown in Fig. 6.

[0204] The breakage was checked by cutting the reinforcing film into 10 mm X 50 mm pieces, holding the corners of the short part and bending it, and then pressing the bent center part completely.

[0205] Comparative Example 2 is a single-membrane anion exchange membrane, not a composite membrane with a reinforcing layer in the center. Therefore, when checking for breakage, it was confirmed that the exchange membrane was completely cut and broken. It was confirmed that Example 2 folded without breaking even when completely bent and pressed in the center, and Example 3 was confirmed to have slightly broken but not completely broken and separated.

[0206]

[0207] Experimental Example 4 - Confirmation of electrolysis performance

[0208] The electrolysis performance was evaluated in Comparative Example 1 and Examples 4 and 5. The performance was evaluated at a cell temperature of 60°C and in a 1 mol KOH solution.

[0209] As a result of comparing Comparative Example 1 with Examples 4 and 5, in the case of the example in which the porous support layer was added, the overall thickness was thicker, so the voltage was somewhat higher at the same hydrogen production volume compared to the Comparative Example, but the difference was minimal.

[0210] Therefore, it was confirmed that when a porous support layer is included, the characteristics such as cracking are improved, but the electrolytic characteristics are not deteriorated.

[0211]

[0212] [Explanation of symbols]

[0213] 100: Anion exchange membrane 1: First carbazole polymer layer

[0214] 2: Porous support layer 3: Second carbazole polymer layer

Claims

1. A first carbazole-based polymer layer; a porous support layer; and a second carbazole-based polymer layer, The above porous support layer is provided between the first carbazole-based polymer layer and the second carbazole-based polymer layer, The total thickness of the first carbazole-based polymer layer, the porous support layer, and the second carbazole-based polymer layer is greater than 40 ㎛ and less than or equal to 170 ㎛. Anion exchange membrane.

2. In paragraph 1, The above porous support comprises at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), and polytetrafluoroethylene (PTFE). Anion exchange membrane.

3. In paragraph 1, An anion exchange membrane wherein the first carbazole polymer and the second carbazole polymer each independently comprise a compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, R1 to R4 are each independently C 1-60 alkylene; C 6-60 Arylene; or C 2-60 It's allylene, The above R1 to R4 may each be independently unsubstituted or substituted with one or more fluorines, The above R1 to R4 may each independently include one or more heteroatoms selected from the group consisting of O, N, and S instead of carbon, The above R1 to R4 may be the same or different for each repeating unit, X1 to X4 may each independently be a hydrogen atom; or an anion exchanger, At least one of the above X1 to X4 is an anion exchanger, The above anion exchanger is at least one independently selected from the group consisting of an amine group, an ammonium group, an amino group, an imine group, a sulfonium group, a phosphonium group, a pyridyl group, a carbazolyl group, an imidazolyl group, or a salt thereof, m or n are each independently an integer from 1 to 100,000.

4. In paragraph 1, The first carbazole polymer layer has a thickness of 5 μm to 73 μm, Anion exchange membrane.

5. In paragraph 1, The second carbazole polymer layer has a thickness of 5 μm to 73 μm, Anion exchange membrane.

6. In paragraph 1, The porous support layer has a thickness of 5 μm to 50 μm, Anion exchange membrane.

7. A step of coating a first carbazole-based polymer composition on a release paper (step 1); A step (step 2) of obtaining a first composite membrane by positioning a porous support on the first carbazole-based polymer composition layer; A step of drying the first composite membrane (step 3); A step of obtaining a second composite membrane by coating a second carbazole-based polymer composition on the porous support of the dried first composite membrane (step 4); A step of drying the second composite membrane (step 5); and Including the step of removing the above-mentioned heteromorphism (step 6), Method for manufacturing an anion exchange membrane.

8. In paragraph 7, The above step 3 is performed at a temperature of 40°C to 150°C. Method for manufacturing an anion exchange membrane.

9. In paragraph 7, The above anion exchange membrane has a total thickness of the first carbazole-based polymer layer, the porous support layer, and the second carbazole-based polymer layer of more than 40 ㎛ and less than or equal to 170 ㎛. Method for manufacturing an anion exchange membrane.

10. In paragraph 7, The above porous support comprises at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), and polytetrafluoroethylene (PTFE). Method for manufacturing an anion exchange membrane.

11. In paragraph 7, A method for manufacturing an anion exchange membrane, wherein the first carbazole-based polymer composition and the second carbazole-based polymer composition each independently include a compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, R1 to R4 are each independently C 1-60 alkylene; C 6-60 Arylene; or C 2-60 It's allylene, The above R1 to R4 may each be independently unsubstituted or substituted with one or more fluorines, The above R1 to R4 may each independently include one or more heteroatoms selected from the group consisting of O, N, and S instead of carbon, The above R1 to R4 may be the same or different for each repeating unit, X1 to X4 may each independently be a hydrogen atom; or an anion exchanger, At least one of the above X1 to X4 is an anion exchanger, The above anion exchanger is at least one independently selected from the group consisting of an amine group, an ammonium group, an amino group, an imine group, a sulfonium group, a phosphonium group, a pyridyl group, a carbazolyl group, an imidazolyl group, or a salt thereof, m or n are each independently an integer from 1 to 100,000.

12. A membrane electrode assembly for a fuel cell, comprising an anion exchange membrane according to any one of claims 1 to 6.

13. A membrane electrode assembly for water electrolysis, comprising an anion exchange membrane according to any one of claims 1 to 6.

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