Membrane electrode assembly for high temperature polymer electrolyte membrane fuel

Abstract

The present invention relates to a membrane electrode assembly for a high temperature polymer electrolyte membrane fuel cell in the form of a catalyst coated film and a method for manufacturing the same. A membrane electrode assembly (MEA) for a polymer electrolyte membrane fuel cell is prepared by applying an electrode slurry onto a release sheet to form an electrode layer, providing an electrolyte membrane including a substrate doped with phosphoric acid, and transferring the electrode layer to produce a catalyst coated membrane (CCM). The electrode slurry includes a catalyst, one or more ionomers, and a solvent, having a solids content of about 10%-15% by weight. A release sheet comprising polyimide and about 30-80 [mu] m thick allows for uniform coating and transfer. The resulting electrolyte membrane having a thickness of about 40-50 [mu] m is doped with about 5-9 mg / cm2 of phosphoric acid and includes a hydrocarbon-based polymer substrate. The final MEA shows a high frequency resistance of about 100 m [Omega] * cm2 or less.

Description

Technical Field

[0001] This disclosure relates to a method for manufacturing membrane electrode assemblies for high-temperature polymer electrolyte membrane fuel cells by a transfer method. Background Technology

[0002] Polymer electrolyte membrane fuel cells (PEMFCs) can be divided into low-temperature and high-temperature types. The difference between the two types of fuel cells lies in the operating temperature and the membrane type.

[0003] Low-temperature PEMFCs operate at approximately 60°C to 80°C, while high-temperature PEMFCs operate at approximately 120°C to 180°C.

[0004] Low-temperature PEMFCs use electrolyte membranes containing perfluorosulfonic acid ionomers such as Nafion, while high-temperature PEMFCs typically use electrolyte membranes containing phosphoric acid-doped polybenzimidazole ionomers. Electrolyte membranes containing perfluorosulfonic acid ionomers require water to conduct hydrogen ions, but electrolyte membranes containing phosphoric acid-doped polybenzimidazole ionomers can conduct hydrogen ions even in the absence of water, making operation at 100°C or higher feasible.

[0005] Meanwhile, polymer electrolyte membrane fuel cells (PEMFCs) include: membrane electrode assemblies comprising an electrolyte membrane and a pair of electrode layers located on two surfaces of the electrolyte membrane, a gas diffusion layer (GDL) on the membrane electrode assembly, and a separator on the gas diffusion layer, etc.

[0006] Membrane electrode assemblies can be categorized into two types: catalyst-coated gas-diffused polymer (GDL) type, in which an electrode layer is coated onto a gas diffusion layer (GDL) to create a laminate, which is then attached to an electrolyte membrane; and catalyst-coated membrane (CCM) type, in which the electrode layer is transferred to the electrolyte membrane. The CCM type is advantageous in terms of good interfacial bonding between the electrode layer and the electrolyte membrane, as well as catalyst utilization.

[0007] In low-temperature PEMFCs, the electrode layer can be easily transferred to the electrolyte membrane because it is solid. However, in high-temperature PEMFCs, the membrane is doped and / or impregnated with liquid phosphoric acid, making transfer more difficult and posing a risk of phosphoric acid leakage under elevated temperature and pressure conditions. Therefore, membrane electrode assemblies for high-temperature PEMFCs are typically fabricated as catalyst-coated gas diffusion layers (CCG). Summary of the Invention

[0008] The purpose of this disclosure is to provide a membrane electrode assembly in the form of a catalyst-coated membrane (CCM) for a high-temperature polymer electrolyte membrane fuel cell and a method thereof for manufacturing the same.

[0009] The purpose of this disclosure is not limited to the foregoing objectives. The objectives of this disclosure will become more apparent from the following description and will be achieved by the apparatus and combinations thereof described in this invention.

[0010] A method for manufacturing a membrane electrode assembly for a polymer electrolyte membrane fuel cell (e.g., a high-temperature polymer electrolyte membrane fuel cell) according to embodiments of the present disclosure may include the following steps: applying an electrode slurry to a release sheet (e.g., paper) to manufacture a laminate including the release sheet and an electrode layer on the release sheet; providing an electrolyte membrane including a substrate and an electrolyte doped into the substrate; and transferring the electrode layer of the laminate onto the electrolyte membrane to manufacture a membrane electrode assembly in the form of a catalyst-coated membrane (CCM).

[0011] Electrode pastes may contain, for example, catalysts, ionomers, and solvent components.

[0012] Electrode slurries can have a solids content concentration of 10% to 15% by weight.

[0013] Ionomers may include at least one selected from the group consisting of perfluorosulfonic acid ionomers, partially fluorophosphate ionomers, and combinations thereof.

[0014] The solvent component may include at least one selected from the group consisting of: alcohol organic solvents; at least one cosolvent selected from the group consisting of amide organic solvents, ketone organic solvents, carbonate organic solvents, ether organic solvents, and combinations thereof; and combinations thereof.

[0015] Release sheets may include polyimide.

[0016] Release sheets can have a thickness of 30 μm or greater up to less than 80 μm.

[0017] The electrode layer can have a thickness of 5.5 μm to 55 μm.

[0018] The substrate can have a phosphate binding energy of 100 kcal / mol or higher.

[0019] The substrate may include at least one selected from the group consisting of phosphorylated phenylated-poly(phenylene), phosphorylated polynorbornene, phosphorylated polycarbazole, and combinations thereof.

[0020] Electrolytes can include phosphoric acid.

[0021] The electrolyte membrane may have a substrate doped with 5 mg / cm³. 2 Up to 9 mg / cm 2 The amount of electrolyte in the electrolyte membrane.

[0022] Electrolyte membranes can have a thickness of 40 μm to 50 μm.

[0023] The electrode layer of the laminate can be transferred to the electrolyte membrane at 120°C to 140°C.

[0024] The electrode layer of the laminate can be transferred to the electrolyte membrane under pressures greater than 3.89 MPa to 5.84 MPa or less.

[0025] A membrane electrode assembly for a polymer electrolyte membrane fuel cell according to embodiments of the present disclosure includes an electrolyte membrane; and an electrode layer on the electrolyte membrane, wherein the electrolyte membrane includes a substrate and an electrolyte doped into the substrate, and may be in the form of a catalyst-coated membrane (CCM).

[0026] Membrane electrode assemblies for polymer electrolyte membrane fuel cells can have a strength of 100 mΩ·cm. 2 Or smaller high-frequency resistors (HFR).

[0027] According to this disclosure, a membrane electrode assembly for polymer electrolyte membrane fuel cells in the form of a catalyst-coated membrane (CCM) and a method for manufacturing the same can be obtained.

[0028] According to this disclosure, a polymer electrolyte membrane fuel cell with a good interface between the electrolyte membrane and the electrode layer, low contact resistance, and excellent performance can be obtained.

[0029] According to this disclosure, a method for manufacturing a membrane electrode assembly for a polymer electrolyte membrane fuel cell can be obtained, which is advantageous for large-scale production and allows for easy control of the area and thickness of the electrode layer.

[0030] As discussed, the method and system appropriately include the use of a controller or processor.

[0031] The effects of this disclosure are not limited to those described above. It should be understood that the effects of this disclosure include all effects that can be inferred from the following description. Attached Figure Description

[0032] Figure 1 A membrane electrode assembly for a high-temperature polymer electrolyte membrane fuel cell is shown according to the present disclosure.

[0033] Figure 2 This is a reference diagram used to illustrate the steps involved in manufacturing a laminate.

[0034] Figure 3A The image shows the application of an electrode paste containing only a portion of fluorophosphate ionomers onto release paper.

[0035] Figure 3B The image shows the application of an electrode paste containing only N-methyl-2-pyrrolidone (NMP) as a solvent onto release paper.

[0036] Figure 3C The image shows the application of an electrode paste containing perfluorosulfonic acid ionomers and partially fluorophosphate ionomers as ionomers and n-propanol (nPA) and N-methyl-2-pyrrolidone (NMP) as solvents onto release paper.

[0037] Figure 4 The use of polyethylene naphthalate (PEN) as the release paper transfer electrode layer is shown.

[0038] Figure 5 The electrode layers are shown by using release paper containing polyimide and having a thickness of 30 μm (left) and release paper containing polyimide and having a thickness of 80 μm (right).

[0039] Figure 6A The electrode layer was transferred to a substrate with a concentration of 9 mg / cm². 2 An electrolyte membrane with phosphoric acid doping.

[0040] Figure 6B The electrode layer was transferred to a substrate with a concentration of 7 mg / cm². 2 An electrolyte membrane with phosphoric acid doping.

[0041] Figure 7 This is a reference diagram used to illustrate the transfer of the electrode layer of a laminate to the electrolyte membrane.

[0042] Figure 8A The electrode layer was transferred to the electrolyte membrane at 120 °C and 1.62 MPa.

[0043] Figure 8B The electrode layer was transferred to the electrolyte membrane at 120 °C and 3.24 MPa.

[0044] Figure 8C The electrode layer was transferred to the electrolyte membrane at 120 °C and 3.89 MPa.

[0045] Figure 8D The electrode layer was transferred to the electrolyte membrane at 120 °C and 4.86 MPa.

[0046] Figure 9 The results of field emission scanning electron microscopy (FE-SEM) analysis of the membrane electrode assembly in the form of a catalyst coated membrane (CCM) according to this disclosure are shown.

[0047] Figure 10 The results of field emission scanning electron microscopy (FE-SEM) analysis of a membrane electrode assembly in the form of a catalyst-coated gas diffusion layer (CCG) are shown.

[0048] Figure 11 The results show the results of measuring the phosphoric acid outflow of a membrane electrode assembly in the form of a catalyst-coated membrane (CCM) according to this disclosure.

[0049] Figure 12 The results show the performance of a membrane electrode assembly in the form of a catalyst-coated membrane (CCM) according to this disclosure. Detailed Implementation

[0050] The above-mentioned objects, other objects, features, and advantages of this disclosure will be readily understood from the following preferred embodiments, taken in conjunction with the accompanying drawings. However, this disclosure is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be thorough and complete, and the spirit of this disclosure may be fully conveyed to those skilled in the art.

[0051] While explaining the figures, similar reference numerals have been used for similar elements. In the figures, for clarity of this disclosure, the dimensions of the structures have been enlarged from actual dimensions.

[0052] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. These terms are intended only to distinguish one component from another, and these terms do not limit the nature, order, or sequence of the constituent components. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Furthermore, the terms “unit,” “device,” “piece,” and “module” described in the specification mean a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0053] Although exemplary embodiments are described as using multiple units to perform exemplary processes, it should be understood that exemplary processes can also be performed by one or more modules. Furthermore, it should be understood that the term controller / control unit refers to a hardware device that includes a memory and a processor and is specifically programmed to perform the processes described herein. The memory is configured to store modules, and the processor is specifically configured to execute said modules to perform one or more processes further described below.

[0054] Furthermore, the control logic of this disclosure may be embodied in a non-volatile computer-readable medium containing executable program instructions that can be executed by a processor, controller, or the like. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage devices. The computer-readable medium may also be distributed across a network-coupled computer system, enabling it to be stored and executed in a distributed manner, for example, via a telematics server or a controller area network (CAN).

[0055] Unless otherwise specified or obvious from the context, as used herein, the term “about” should be understood as being within the normal tolerance range in the field, such as within 2 standard deviations of the mean. “About” can be understood as being within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. All numerical values ​​provided herein are modified by the term “about” unless the context clearly indicates otherwise.

[0056] In this specification, terms such as "comprising" and "having" are intended to specify the presence of the features, quantities, steps, operations, components, parts, or combinations thereof described herein. However, it should be understood that these terms do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts, or combinations thereof. Furthermore, when a portion of a layer, membrane, region, plate, etc., is referred to as being "on" other portions, this includes not only the case where it is "directly" on the other portions, but also the case where another portion exists between them. Conversely, when a portion of a layer, membrane, region, plate, etc., is stated as being "below" other portions, this includes not only the case where it is "directly below" the other portions, but also the case where another portion exists between them.

[0057] Unless otherwise specified, all figures, values, and / or expressions used in this specification to represent the amounts of components, reaction conditions, polymer compositions, and formulations are approximations reflecting the various uncertainties in the measurement that arise in obtaining these values ​​(where, among other things, these figures are substantially different), and therefore should be understood to be modified by the term "about" in all cases. Furthermore, when numerical ranges are disclosed in this specification, such ranges are continuous and include all values ​​from the minimum to the maximum (inclusive) of such ranges, unless otherwise specified. Furthermore, when such ranges refer to integers, all integers from the minimum to the maximum (inclusive) are included, unless otherwise specified.

[0058] Figure 1 A membrane electrode assembly for a high-temperature polymer electrolyte membrane fuel cell according to the present disclosure is shown. The membrane electrode assembly may include an electrolyte membrane 10 and electrode layers 20 and 20' on the electrolyte membrane 10. When electrode layer 20 on one surface of the electrolyte membrane 10 is a cathode, electrode layer 20' on the other surface may be an anode.

[0059] The membrane electrode assembly can be in the form of a catalyst-coated membrane (CCM). The catalyst-coated membrane form can represent electrode layers 20 and 20' being attached to and integrated into the electrolyte membrane 10 in a series of ways. Specifically, electrode layers 20 and 20' can be transferred to both surfaces of the electrolyte membrane 10.

[0060] A method for manufacturing a membrane electrode assembly for a high-temperature polymer electrolyte membrane fuel cell according to the present disclosure may include the following steps: manufacturing a laminate comprising a release paper and an electrode layer on the release paper, preparing an electrolyte membrane, and transferring the electrode layer of the laminate to the electrolyte membrane to manufacture a membrane electrode assembly in the form of a catalyst-coated membrane (CCM).

[0061] Figure 2 This is a reference diagram illustrating the steps involved in manufacturing a laminate. A laminate can be obtained by applying an electrode paste to the release paper 30 to form an electrode layer 20 on the release paper 30.

[0062] Electrode slurries may contain, for example, catalysts, ionomers, and solvents.

[0063] The catalyst may include platinum (Pt / C) supported on a carbon support. The platinum content is not particularly limited and may be, for example, from about 40% to about 60% by weight based on the total weight of the catalyst.

[0064] Ionomers may include perfluorosulfonic acid ionomers or partially fluorophosphate ionomers, with perfluorosulfonic acid ionomers and partially fluorophosphate ionomers being preferred. Perfluorosulfonic acid ionomers are ionomers whose hydrogen ion-conducting groups are sulfonic acid groups, and their main chain may be polytetrafluoroethylene (PTFE), and their side chains may include sulfonic acid groups (-SO3H), with Nafion being preferred. Partially fluorophosphate ionomers are ionomers whose hydrogen ion-conducting groups are phosphate groups (phosphate groups, -PH2O3), and may include poly(2,3,5,6-tetrafluorostyrene-4-phosphate), compounds represented by Formula 1, etc.

[0065] [Formula 1]

[0066]

[0067] In Equation 1, n1 is 0.7a, n2 is 0.3a, and a can be a number belonging to the range 100 to 10,000.

[0068] Ionomers may include perfluorosulfonic acid ionomers and partially fluorophosphate ionomers in a mass ratio of 3:7 to 5:5 or 4:6. When the mass ratio of the ionomers falls within the above range, the electrode paste exhibits excellent dispersibility and can be uniformly applied to the release paper.

[0069] Figure 3A The image shows the application of an electrode paste containing only a portion of fluorophosphate ionomers onto release paper. Referring to this, it can be seen that when only a portion of the fluorophosphate ionomers are used, the electrode paste cannot be applied evenly to the release paper.

[0070] Solvents may include hydrophilic solvents to reduce adhesion strength to the release paper but increase adhesion strength to the electrolyte membrane. Specifically, solvents may include at least one selected from the group consisting of: alcoholic organic solvents; at least one cosolvent selected from the group consisting of amide organic solvents, ketone organic solvents, carbonate organic solvents, ether organic solvents, and combinations thereof; and combinations thereof. To improve the dispersibility of the ionomer, the cosolvent may be mixed with an alcoholic organic solvent, and preferably, alcoholic organic solvents and amide organic solvents may be used in combination.

[0071] Alcoholic organic solvents may include alcohols having 1 to 4 carbon atoms, preferably n-propanol (nPA).

[0072] Amide organic solvents may include formamide (FA), N-methylformamide (NMFA), N,N-dimethylformamide (DMF), acetamide (AA), N-methylacetamide (NMAA), N,N-dimethylacetamide (DMA), N-methyl-2-pyrrolidone (NMP), etc., preferably N-methyl-2-pyrrolidone (NMP).

[0073] Ketone organic solvents can include acetone, methyl ethyl ketone (MEK), methyl butyl ketone (MBK), methyl isobutyl ketone (MIBK), etc.

[0074] Carbonate organic solvents can include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentene carbonate, 2,3-pentene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, etc.

[0075] Ether organic solvents may include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, 1,4-dioxane, tetrahydrofuran, anisole, etc.

[0076] Figure 3B The diagram shows the application of an electrode paste containing only N-methyl-2-pyrrolidone (NMP) as a solvent onto release paper. Referring to this, it can be seen that if only N-methyl-2-pyrrolidone (NMP) is used, the electrode paste cannot be applied evenly to the release paper.

[0077] Figure 3C The illustration shows the application of an electrode paste containing perfluorosulfonic acid ionomers and partially fluorophosphate ionomers as ionomers, and n-propanol (nPA) and N-methyl-2-pyrrolidone (NMP) as solvents onto release paper. Referring to this, it can be seen that the electrode paste can only be uniformly applied to the release paper when the ionomers and solvents are used in combination as described in this disclosure.

[0078] Electrode slurries can have a solids content concentration of 10% to 15% by weight. Solids content concentration refers to the content of solid components (such as catalysts, ionomers, etc.) excluding solvent contents in the electrode slurry. If the solids content concentration is less than 10% by weight, the viscosity is low, making it difficult to coat release paper with the electrode slurry, and the catalyst content can be low. If the solids content concentration exceeds 15% by weight, the catalyst and ionomers can lump together, making it difficult to coat release paper with the electrode slurry and hindering the formation of the three-phase interface.

[0079] There are no particular limitations on the method used to prepare the electrode slurry, and the electrode slurry can be prepared, for example, by introducing the catalyst and ionomer into the solvent, mixing them with a slurry mixer for about 30 minutes, dispersing them with a high-shear homogenizer for about 60 minutes, and defoaming them for about 20 minutes.

[0080] Release paper 30 may include polyimide. When polyimide is used, the adhesive strength between electrode layer 20 and release paper 30 is reduced, allowing electrode layer 20 to be neatly transferred onto electrolyte membrane 10.

[0081] Release paper 30 can have a thickness of 30 μm or greater up to less than 80 μm. If the thickness of release paper 30 is less than 30 μm, processability deteriorates, while if it is 80 μm or greater, it may not be suitable for transfer processes.

[0082] Figure 4 The diagram shows the use of polyethylene naphthalate (PEN) as the electrode transfer layer on the release paper. Referring to this, it can be seen that a considerable amount of electrode layer residue remains on the release paper.

[0083] Figure 5 The transfer of electrode layers is shown using release paper containing polyimide and having a thickness of 30 μm (left) and release paper containing polyimide and having a thickness of 80 μm (right). Referring to this, it can be seen that when using release paper with a thickness of 30 μm formed of polyimide, the electrode layer can be transferred cleanly; however, when the thickness is increased to 80 μm, a considerable amount of electrode layer residue remains on the release paper.

[0084] In this disclosure, since the electrode layer 20 is formed on the release paper 30 rather than on the gas diffusion layer, and the electrode layer 20 is transferred to the electrolyte membrane 10, the thickness of the electrode layer 20 is easily controlled. When the electrode paste is applied to the gas diffusion layer to form the electrode layer 20, a portion of the electrode paste permeates into the gas diffusion layer, making it difficult to control the thickness of the electrode layer 20, and also making it impossible to control the surface of the electrode layer 20.

[0085] The electrode layer 20 can have a thickness of 5.5 μm to 55 μm, and the thickness can be controlled according to the catalyst loading. For example, when the catalyst loading is 0.15 mg / cm³... 2 Up to 0.35 mg / cm 2 At this time, the electrode layer 20 can have a thickness of 5.5 μm to 19.5 μm. When the catalyst loading is 0.35 mg / cm³... 2 Up to 0.7 mg / cm 2 At this time, the electrode layer 20 can have a thickness of 19.5 μm to 38.5 μm. When the catalyst loading is 0.7 mg / cm³...2 Up to 1.0 mg / cm 2 In this case, the electrode layer 20 can have a thickness of 38.5 μm to 54.0 μm.

[0086] The electrolyte membrane 10 may include a substrate and an electrolyte doped into the substrate. The substrate may be in the form of a sheet and may be porous. Here, "doping" may refer to impregnating the interior of the porous substrate with the electrolyte.

[0087] The substrate can be hydrogen ion conductive.

[0088] Furthermore, the substrate can have a phosphate binding energy of 100 kcal / mol or greater to prevent electrolyte efflux after the transfer process. The binding energy can be calculated using the density-based theory with the ωB97XD function and 6-311++G(2d,2p) as the basis set.

[0089] The substrate that satisfies the above conditions may include a hydrocarbon polymer having a quaternary ammonium group introduced therein, and specifically may include at least one selected from the group consisting of: phosphorylated phenyl-poly(phenylene), phosphorylated polynorbornene, phosphorylated polycarbazole, and combinations thereof.

[0090] The above phosphorylated phenyl-poly(phenylene) can include compounds represented by the following formula 2.

[0091] [Equation 2]

[0092]

[0093] In Equation 2, n3 can be a number belonging to 100 to 10,000, and m1 can be a number belonging to 2 to 10.

[0094] The above phosphorylated polynorbornene may include compounds represented by the following formula 3.

[0095] [Formula 3]

[0096]

[0097] In Equation 3, n4 can be a number belonging to 100 to 10,000, and m2 can be a number belonging to 2 to 10.

[0098] The aforementioned phosphorylated polycarbazole may include compounds represented by Formula 4 below.

[0099] [Formula 4]

[0100]

[0101] In Equation 4, n5 is a number belonging to 100 to 10,000, and m3 and m4 can be numbers belonging to 2 to 10 respectively.

[0102] Electrolytes can include phosphoric acid. Phosphoric acid can be in liquid form.

[0103] Electrolyte membrane 10 can pass through 5 mg / cm 2 Up to 9 mg / cm 2 5mg / cm 2 Up to 8 mg / cm 2 And more preferably 5 mg / cm 2 Up to 7 mg / cm 2 This is achieved by doping the substrate with a certain amount of electrolyte. If the electrolyte doping amount is less than 5 mg / cm³, the desired result is obtained. 2 If this occurs, the performance of the fuel cell can deteriorate, and if it exceeds 9 mg / cm³, the performance will be further reduced. 2 If this happens, electrode layer 20 may not be able to be transferred cleanly.

[0104] Figure 6A The electrode layer was transferred to a substrate with a concentration of 9 mg / cm². 2 The electrolyte membrane has an excessive amount of phosphoric acid doping. Referring to this, it can be seen that the electrolyte membrane 10 is immersed in excessive phosphoric acid, causing the electrode layer 20 to be unable to transfer completely and a portion of it to remain on the release paper 30.

[0105] Figure 6B The electrode layer was transferred to a substrate with a concentration of 7 mg / cm². 2 The electrolyte membrane is doped with phosphoric acid. Referring to this, it can be seen that the electrode layer 20 is cleanly transferred to the electrolyte membrane 10.

[0106] The thickness of the electrolyte membrane 10 is not particularly limited, for example, it can be 40 μm to 50 μm. When the thickness of the electrolyte membrane 10 falls within the above-mentioned range, the processability is excellent and the performance of the fuel cell can be improved.

[0107] Figure 7 This is a reference diagram illustrating the transfer of the electrode layer 20 of the laminate to the electrolyte membrane 10. A membrane electrode assembly in the form of a catalyst-coated membrane (CCM) can be manufactured by applying a predetermined amount of heat and pressure to the electrolyte membrane 10 after the laminate has been adhered to it, such that the electrode layer 20 of the laminate faces the electrolyte membrane 10.

[0108] Specifically, electrode layer 20 can be transferred to electrolyte membrane 10 at temperatures between 120°C and 140°C and pressures greater than 3.89 MPa to 5.84 MPa or less. When the transfer temperature conditions fall within the above-mentioned range, the electrolyte doped in electrolyte membrane 10 can move to electrode layer 20 while sufficiently removing moisture. If the transfer pressure is 3.89 MPa or less, electrode layer 20 cannot be transferred cleanly; if the transfer pressure exceeds 5.84 MPa, there is a possibility that electrolyte may flow out.

[0109] Figure 8A The electrode layer 20 was transferred to the electrolyte membrane 10 at 120 °C and 1.62 MPa. Figure 8B The electrode layer 20 was transferred to the electrolyte membrane 10 at 120 °C and 3.24 MPa. Figure 8C The transfer of electrode layer 20 to electrolyte membrane 10 is shown under conditions of 120°C and 3.89 MPa. Referring to this, it can be seen that when the transfer pressure is 3.89 MPa or lower, electrode layer 20 cannot be cleanly transferred to electrolyte membrane 10.

[0110] Figure 8D The transfer of electrode layer 20 to electrolyte membrane 10 was demonstrated under conditions of 120 °C and 4.86 MPa. It can be confirmed that when the temperature and pressure conditions for transfer are the same as those of this disclosure, electrode layer 20 transfers well to electrolyte membrane 10.

[0111] Figure 9 The results of field emission scanning electron microscopy (FE-SEM) analysis of the membrane electrode assembly in the form of a catalyst coated membrane (CCM) according to this disclosure are shown. Figure 10 The results of field emission scanning electron microscopy (FE-SEM) analysis of a membrane electrode assembly in the form of a catalyst-coated gas diffusion layer (CCG) are shown.

[0112] refer to Figure 10 It can be seen that the catalyst-coated gas diffusion layer (CCG) membrane electrode assembly exhibits a large thickness variation in the electrode layer due to the coating of the electrode layer on its uneven gas diffusion layer surface, and the adhesion between the electrolyte membrane and the electrode layer is reduced. Furthermore, the platinum (Pt) results from energy-dispersive X-ray spectroscopy (EDS) show that platinum has permeated into the gas diffusion layer, which reduces catalyst utilization and contributes to thickness inhomogeneity. Phosphorus (P) analysis confirms that the migration of phosphoric acid, as the electrolyte, from the electrolyte membrane to the electrode layer is uneven.

[0113] refer to Figure 9The catalyst-coated membrane electrode assembly (CCM) exhibits minimal thickness variation in the electrode layer and excellent interfacial bonding between the electrolyte membrane and the electrode layer. Energy-dispersive X-ray spectroscopy (EDS) analysis of platinum (Pt) indicates a highly uniform electrode layer. Furthermore, phosphorus (P) analysis confirms the uniform movement of phosphoric acid, acting as the electrolyte, throughout the entire membrane electrode assembly.

[0114] Figure 11 Results of measuring phosphoric acid outflow in a membrane electrode assembly in the form of a catalyst-coated membrane (CCM) according to this disclosure are shown. For comparison, phosphoric acid outflow in a membrane electrode assembly in the form of a catalyst-coated gas diffusion layer (CCG) is also shown. Specifically, the amount of phosphoric acid escaping through the gas diffusion layer after 6 hours of cell operation was measured at the anode channel, cathode channel, and outlet. (Refer to...) Figure 11 The phosphoric acid outflow of the membrane electrode assembly in the form of a catalyst-coated membrane (CCM) according to this disclosure is significantly smaller. Furthermore, in the form of a catalyst-coated gas diffusion layer (CCG), the phosphoric acid permeating into the gas diffusion layer is not used as an electrolyte and flows out during battery operation.

[0115] Figure 12 Results of performance measurements for membrane electrode assemblies in the form of catalyst-coated membranes (CCMs) according to this disclosure are shown. For comparison, the performance of membrane electrode assemblies in the form of catalyst-coated gas diffusion layers (CCGs) is also shown. Specifically, the IV performance of each cell was evaluated under conditions of 160 °C, a hydrogen flow rate of 500 sccm, an oxygen flow rate of 2,500 sccm, and a pressure of 1.5 bar. Peak power density (PPD), as a performance indicator, and high-frequency resistance (HFR), as a contact resistance indicator, are shown in Table 1 below.

[0116] [Table 1]

[0117] item <![CDATA[PPD[W / cm 2 ]]]> <![CDATA[HFR[mΩ·cm 2 ]]]> CCM 0.705 94 CCG 0.570 140

[0118] Reference Figure 12 As can be seen from Table 1, due to the uniform transfer of the electrode layer onto the electrolyte membrane, the membrane electrode assembly in the form of a catalyst-coated membrane (CCM) according to this disclosure exhibits low contact resistance and excellent performance between the electrolyte membrane and the electrode layer. Specifically, it is characterized by a contact resistance index (HFR) of 100 mΩ·cm. 2 Or smaller.

[0119] Although embodiments of the present disclosure have been described above, those skilled in the art will understand that the present disclosure can be implemented in other specific forms without altering its technical concept or essential characteristics. Therefore, it should be understood that the above embodiments are exemplary and not restrictive in all respects.

Claims

1. A method for manufacturing a membrane electrode assembly for a polymer electrolyte membrane fuel cell, the method comprising: Electrode paste is applied to a release sheet to manufacture a laminate comprising the release sheet and an electrode layer on the release sheet; An electrolyte membrane is provided, the electrolyte membrane comprising a substrate and an electrolyte doped into the substrate; and The electrode layer of the laminate is transferred onto the electrolyte membrane to manufacture a membrane electrode assembly in the form of a catalyst-coated membrane.

2. The method according to claim 1, wherein the electrode slurry comprises a catalyst, an ionomer, and a solvent component.

3. The method according to claim 1, wherein the electrode slurry has a solids content concentration of 10% to 15% by weight.

4. The method according to claim 2, wherein the ionomer comprises perfluorosulfonic acid ionomers, partially fluorophosphate ionomers, or combinations thereof.

5. The method according to claim 2, wherein the solvent component comprises an alcoholic organic solvent; at least one cosolvent selected from the group consisting of amide organic solvents, ketone organic solvents, carbonate organic solvents, ether organic solvents, and combinations thereof; or combinations thereof.

6. The method of claim 1, wherein the release sheet comprises polyimide.

7. The method of claim 1, wherein the release liner has a thickness of 30 μm or greater and less than 80 μm.

8. The method of claim 1, wherein the substrate comprises a hydrocarbon polymer having a quaternary ammonium group, optionally selected from the group consisting of phosphorylated phenyl-poly(phenylene), phosphorylated polynorbornene, phosphorylated polycarbazole, and combinations thereof.

9. The method of claim 1, wherein the electrolyte comprises phosphoric acid.

10. The method according to claim 1, wherein the electrolyte membrane is wherein the substrate is doped with 5 mg / cm³. 2 Up to 9 mg / cm 2 The amount of the electrolyte in the electrolyte membrane.

11. The method of claim 1, wherein the electrolyte membrane has a thickness of 40 μm to 50 μm, and the electrode layer has a thickness of 5.5 μm to 55 μm.

12. The method of claim 1, wherein the electrode layer of the laminate is transferred to the electrolyte membrane at a temperature of 120°C to 140°C to manufacture the membrane electrode assembly.

13. The method of claim 1, wherein the electrode layer of the laminate is transferred to the electrolyte membrane at a pressure of 3.89 MPa to 5.84 MPa to manufacture the membrane electrode assembly.

14. A membrane electrode assembly for a polymer electrolyte membrane fuel cell, the membrane electrode assembly comprising: Electrolyte membrane; and an electrode layer on the electrolyte membrane, wherein the electrolyte membrane comprises a substrate and an electrolyte doped into the substrate, and the electrolyte membrane is in the form of a catalyst-coated membrane.

15. The membrane electrode assembly of claim 14, wherein the electrolyte membrane has a thickness of 40 μm to 50 μm, and the electrode layer has a thickness of 5.5 μm to 55 μm.

16. The membrane electrode assembly of claim 14, wherein the substrate has a phosphate binding energy of 100 kcal / mol or greater.

17. The membrane electrode assembly of claim 16, wherein the substrate comprises a hydrocarbon polymer having a quaternary ammonium group, optionally selected from the group consisting of phosphorylated phenyl-poly(phenylene), phosphorylated polynorbornene, phosphorylated polycarbazole, and combinations thereof, and the electrolyte comprises phosphoric acid.

18. The membrane electrode assembly of claim 14, wherein the electrolyte membrane is wherein the substrate is doped with 5 mg / cm³. 2 Up to 9 mg / cm 2 The amount of the electrolyte in the electrolyte membrane.

19. The membrane electrode assembly of claim 14, wherein the electrode layer comprises a catalyst and an ionomer, and the ionomer comprises a perfluorosulfonic acid ionomer, a partially fluorophosphate ionomer, or a combination thereof.

20. The membrane electrode assembly according to claim 14, having a Ω·cm... 2 Or even smaller high-frequency resistors.

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