Polymer electrolyte membranes, membrane-electrode assemblies, and fuel cells containing the same.

Abstract

A polymer electrolyte membrane is disclosed that maintains the moisture content within the polymer electrolyte membrane under high temperature and / or low humidity conditions, thereby improving ionic conductivity. [Solution] According to one embodiment, a polymer electrolyte membrane is provided, comprising a porous support, a first ion conductor layer disposed on a first surface of the porous support, and a second ion conductor layer disposed on a second surface opposite to the first surface of the porous support, wherein the first ion conductor layer contains an ion conductor and a water-absorbing compound, the water-absorbing compound forming a basket structure through molecular motion, and the second ion conductor layer does not contain the water-absorbing compound.

Description

[Technical Field]

[0001] The present invention relates to an ion conductor composition, and more specifically to an ion conductor composition, a polymer electrolyte membrane, a membrane-electrode assembly, and a fuel cell comprising the same. [Background technology]

[0002] Fuel cells are batteries equipped with a power generation system that directly converts the energy from chemical reactions, such as the oxidation / reduction reaction between hydrogen and oxygen contained in hydrocarbon fuel materials like methanol, ethanol, and natural gas, into electrical energy. Due to their high energy efficiency and environmentally friendly characteristics, such as low pollutant emissions, they are attracting attention as a next-generation clean energy source that can replace fossil fuels. Fuel cells are classified into alkaline electrolyte membrane fuel cells and polymer electrolyte membrane fuel cells (PEMFCs) depending on the state and type of electrolyte. Among these, polymer electrolyte membrane fuel cells are attracting attention as portable, vehicle, and household power supply devices due to their advantages such as low operating temperature of less than 100°C, fast starting and response characteristics, and excellent durability. Representative examples of polymer electrolyte membrane fuel cells include proton exchange membrane fuel cells (PEMFCs) that use hydrogen gas as fuel, and direct methanol fuel cells (DMFCs) that use liquid methanol as fuel.

[0003] To summarize the reactions that occur in polymer electrolyte membrane fuel cells, first, when a fuel such as hydrogen gas is supplied to the anode electrode, the hydrogen gas undergoes an oxidation reaction at the anode electrode, producing hydrogen ions (H + ) and electrons (e -) is generated. The generated hydrogen ions are transferred to the cathode electrode through the polymer electrolyte membrane, and the generated electrons are transferred to the cathode electrode through an external circuit. At the cathode electrode, oxygen gas is supplied, and the oxygen combines with the hydrogen ions and electrons to produce water through the reduction reaction of oxygen.

[0004] On the other hand, many technical hurdles remain to be overcome in order to commercialize polymer electrolyte membrane fuel cells, and essential improvements include achieving high performance, long lifespan, and low cost. The component that has the greatest impact on this is the membrane-electrode assembly, and among them, the polymer electrolyte membrane is one of the core elements that has the greatest impact on the performance and price of the MEA. The requirements for the polymer electrolyte membrane necessary for the operation of the polymer electrolyte membrane fuel cell include high hydrogen ion conductivity, chemical stability, low fuel permeability, high mechanical strength, and excellent dimensional stability. Conventional polymer electrolyte membranes tend not to perform well under certain temperature and relative humidity environments, especially high temperature or low humidity conditions. As a result, polymer electrolyte membrane fuel cells using conventional polymer electrolyte membranes are limited in their range of application.

[0005] In particular, to overcome the problem of high performance of polymer electrolyte membranes being difficult to achieve under high temperature and / or low humidity conditions, research is continuously being conducted on improving the ionic conductivity of polymer electrolyte membranes by introducing hygroscopic substances into the polymer electrolyte membrane. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a polymer electrolyte membrane that maintains the moisture content within the polymer electrolyte membrane under high temperature and / or low humidity conditions, thereby improving ionic conductivity performance.

[0007] Another object of the present invention is to provide a polymer electrolyte membrane that absorbs moisture generated in the cathode during the operation of a fuel cell and makes the moisture distribution within the polymer electrolyte membrane uniform.

[0008] A further object of the present invention is to provide a polymer electrolyte membrane that minimizes anodic drying (a phenomenon of depletion of water and moisture in the anode) and water flooding (a phenomenon of excess water and moisture in the cathode), as well as the mass transport resistance caused by the aforementioned phenomena.

[0009] Another object of the present invention is to provide a membrane-electrode assembly comprising the polymer electrolyte membrane.

[0010] A further object of the present invention is to provide a fuel cell comprising the membrane-electrode assembly.

[0011] The objectives of the present invention are not limited to those mentioned above, and other objectives and advantages of the present invention not mentioned will be understood from the following description and will be more clearly understood from the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be achieved by the means and combinations set forth in the claims. [Means for solving the problem]

[0012] To achieve the above objective, according to a first aspect of the present invention, a polymer electrolyte membrane is provided comprising a porous support, a first ion conductor layer disposed on a first surface of the porous support, and a second ion conductor layer disposed on a second surface of the porous support opposite to the first surface, wherein the first ion conductor layer comprises an ion conductor and a water-absorbing compound, the water-absorbing compound forms a basket structure through molecular motion, and the second ion conductor layer does not contain a water-absorbing compound.

[0013] According to a second aspect of the present invention, in the first aspect, the water-absorbing compound in the first ion conductor layer can include at least one or more of the following: a hexadentate ligand; an aliphatic ring compound having 5 to 6 carbon atoms and containing 4 or more hydrophilic functional groups in the side chain; a 4-pyrrole containing compound; a triazole compound containing 3 or more hydrophilic functional groups in the side chain; a phosphanilic acid compound; a compound containing 2 or more benzene rings in the molecule; a chain compound containing an amine group and a carboxyl group; and a crown ether compound.

[0014] According to a third aspect of the present invention, in the second aspect, the hexadentate ligand may be any one selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), and combinations thereof.

[0015] According to a fourth aspect of the present invention, in the second or third aspect, the aliphatic ring compound having 5 to 6 carbon atoms and containing 4 or more hydrophilic functional groups in the side chain can include phytic acid.

[0016] According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the 4-pyrrole containing compound can include any one selected from the group consisting of substituted or unsubstituted porphine; substituted or unsubstituted phthalocyanine; and combinations thereof.

[0017] According to a sixth aspect of the present invention, in any one of the second to fifth aspects, the triazole compound containing 3 or more hydrophilic functional groups in the side chain can include deferasirox.

[0018] According to the seventh aspect of the present invention, in any one of the second to sixth aspects, the crown ether compound can include a molecular structure represented by the following general formula 1 as a parent body.

[0019] [General formula 1]

[0020] [C2H4O] n

[0021] In the general formula 1, n is 3 to 10. Here, n may be 3, 4, 5, 6, 7, 8, 9 or 10.

[0022] According to the eighth aspect of the present invention, in any one of the first to seventh aspects, the ion conductor may be contained in the internal pores of the porous support.

[0023] According to the ninth aspect of the present invention, there is provided a membrane - electrode assembly including an anode, a cathode, and a polymer electrolyte membrane according to any one of the first to eighth aspects disposed between the anode and the cathode, wherein the first ion conductor layer is in contact with the anode.

[0024] According to the tenth aspect of the present invention, there is provided a fuel cell including the membrane - electrode assembly according to the ninth aspect.

[0025] The means for solving the above problems do not enumerate all the features of the present invention and may be combined with some embodiments of this specification. The various features of the present invention and the advantages and effects thereof will be understood in more detail by referring to the following specific description.

Effects of the Invention

[0026] According to one aspect of the present invention, it is possible to maintain the moisture content within the polymer electrolyte membrane under high temperature and / or low humidity conditions, thereby improving ionic conductivity performance. This not only allows for the absorption of moisture generated at the cathode during fuel cell operation, resulting in a uniform moisture distribution within the polymer electrolyte membrane, but also reduces the mass transport resistance formed by excess water generated at the cathode.

[0027] Along with the effects described above, the specific effects of the present invention will be described in conjunction with the following explanation of the specific details for carrying out the invention. [Brief explanation of the drawing]

[0028] [Figure 1A] This is a cross-sectional view of a polymer electrolyte membrane according to one embodiment of the present invention.

[0029] [Figure 1B] This is a cross-sectional view showing a membrane-electrode assembly according to one embodiment of the present invention.

[0030] [Figure 2] This is a schematic diagram showing a fuel cell according to one embodiment of the present invention. [Modes for carrying out the invention]

[0031] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0032] In this specification, a range of numbers indicated using the term "~" refers to a range of numbers that includes the values ​​described before and after the term as the lower and upper limits, respectively. If multiple values ​​are disclosed for the upper and lower limits of any given range of numbers, the range of numbers disclosed in this specification can be understood as any range of numbers whose lower limit and upper limit are any one of the multiple lower limits and any one of the multiple upper limits, respectively. For example, if the specification states a~b or c~d, it can be understood that it describes a range of values ​​between a and b, a and d, c and d, or c and b.

[0033] In this specification, "at least one of a, b and c" may include a, b, or c individually, or two or more combinations selected from the group consisting of a, b, and c.

[0034] In this specification, a “layer” or “film” may include cases where, when observing the region in which the layer or film exists, it is formed not only over the entire region but also over only a portion of the region. For example, the surface of the layer or film may be defined as having a flattened form, a non-flattened form, and a combination thereof; or a continuous form, a discontinuous form, and a combination thereof. For example, when one member is directly on top of another member, the coverage of the other member over the surface of the first member may be defined as 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 99% or more. For example, a “layer” or “film” may also be defined when multiple particles are clustered together to form a structure.

[0035] As used herein, unless otherwise defined, "substituted" means that at least one or more hydrogen atoms are replaced by any one selected from the group consisting of a halogen atom, a hydroxy group, a carboxyl group, a nitro group, an amine group, a sulfide group, a thiol group, an alkoxy group, an acetoxy group, a nitrile group, an aldehyde group, an ether group, an ester group, an acetal group, a ketone group, an alkyl group having C1 to C 30 of an alkyl group having C2 to C 30 of an alkenyl group having C2 to C 30 of an alkynyl group having C2 to C 40 of an alkylsilyl group having C1 to C 40 of an arylsilyl group having C5 to C 30 of a cycloalkyl group having C3 to C 30 of an allyl group having C3 to C 30 of an aryl group having C6 to C, a heterocyclic group (e.g., a heterocycloalkyl group having C2 to C 30 of a heterocycloalkyl group having C3 to C 30 of a heteroaryl group), derivatives thereof, and any one combination thereof. Here, when the respective substituents are adjacent to each other, they may be bonded to each other to form a substituted or unsubstituted fused ring or spiro structure.

[0036] As used herein, "fused ring" means a ring in which two or more rings are bonded by sharing two or more atoms, and can include, for example, a fused aliphatic ring, a fused aromatic ring, a fused heteroaliphatic ring, a fused heteroaromatic ring, or a combined form thereof.

[0037] As used herein, "spiro structure" has a spiro linkage, and the spiro linkage means a linkage in which two rings are connected by sharing only one atom.

[0038] In this specification, "basket structure" refers to a structure that forms a cage structure through molecular motion, specifically a structure in which a part of the molecule may move closer to or further away from other parts of the molecule due to molecular motion, and more specifically, a structure in which a cage shape is formed when a part of the molecule moves closer to other parts of the molecule. For example, the aforementioned cage structure may refer to a structure in which a lone pair of electrons in the molecule can form a coordinate bond or ionic bond with a metal or metal ion, or a structure in which a lone pair of electrons in the molecule can interact with a metal or metal ion to form a complex compound. As a quantitative analytical method to determine whether or not a structure is a cage structure, one of the following methods can be used: FT-IR (Fourier transform infrared) Spectrometer, NMR (Nuclear Magnetic Resonance), Raman spectroscopy, XRD (X-ray diffraction), MD simulation, or a combination thereof. For example, when the water-absorbing compound forms a cage structure through molecular motion, the shortest distance between the closest adjacent atomic groups, atoms, or functional groups within the molecule may be 500 Å or less, 400 Å or less, 300 Å or less, 200 Å or less, 100 Å or less, 90 Å or less, 80 Å or less, 70 Å or less, 60 Å or less, 50 Å or less, 40 Å or less, 30 Å or less, 20 Å or less, 10 Å or less, 1 Å or less, or 0.1 Å or less. Here, the shortest distance can be analyzed by X-ray diffraction or MD simulation.

[0039] One embodiment of the present invention provides an ion conductor composition comprising an ion conductor and a water-absorbing compound, wherein the water-absorbing compound forms a basket structure through molecular motion. According to one aspect of the present invention, the water-absorbing compound that forms a basket structure through molecular motion can maintain the water content within the polymer electrolyte membrane under high temperature and / or low humidity conditions, thereby improving ion conductivity performance. This not only allows for the absorption of excess water molecules generated at the cathode during fuel cell operation, resulting in a uniform water distribution within the polymer electrolyte membrane, but also minimizes mass transport resistance due to excess water.

[0040] The configuration of the present invention will be described in more detail below.

[0041] 1. Ionic Conductor Composition

[0042] The ion conductor composition according to the present invention may include an ion conductor dispersion and a water-absorbing compound.

[0043] The water-absorbing compound according to the present invention forms a basket structure through molecular motion. Specifically, the basket structure has the property of effectively capturing water during the operation of the fuel cell, thereby maintaining the moisture content within the polymer electrolyte membrane even under high temperature and / or low humidity conditions. By introducing the compound that forms the basket structure, the ionic conductivity performance of the polymer electrolyte membrane can be improved, and moisture generated at the cathode during the operation of the fuel cell can be effectively absorbed, resulting in a uniform moisture distribution within the polymer electrolyte membrane.

[0044] The water-absorbing compound according to the present invention may contain at least one of the following: hexadentate ligands; aliphatic ring compounds having 5 to 6 carbon atoms and containing 4 or more hydrophilic functional groups in their side chains; 4-pyrrole-containing compounds; triazole compounds containing 3 or more hydrophilic functional groups in their side chains; phosphanic acid compounds; compounds containing 2 or more benzene rings in their molecule; chain-like compounds containing amine and carboxyl groups; and crown ether compounds. Specifically, it may contain a 4-pyrrole-containing compound, and more specifically, it may contain substituted or unsubstituted porphine. Here, the 4-pyrrole-containing compound has a relatively superior water-capturing capacity compared to other types of cage-structure compounds, further increasing the ionic conductivity of the membrane-electrode assembly, improving water retention capacity, and achieving the effect of increasing water content even under high temperature and low humidity conditions.

[0045] In some cases, the hexadentate ligand can effectively absorb or capture water by readily forming a cage structure through attractive and repulsive forces between electron pairs. The readily formed cage structure due to molecular motion can improve the ionic conductivity of the polymer electrolyte membrane and allow for the absorption of moisture generated at the cathode during fuel cell operation, thereby creating a uniform moisture distribution within the polymer electrolyte membrane. The hexadentate ligand may be, for example, one selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), and combinations thereof.

[0046] In some examples, a C5-C6 aliphatic ring compound containing four or more hydrophilic functional groups in its side chain can easily form a cage structure through molecular motion, where the four or more hydrophilic functional groups form hydrogen bonds within the molecule. That is, the aliphatic ring compound can contain cyclopentane or cyclohexane as its parent material, and the side chain can be entirely replaced with hydrophilic functional groups to easily form a cage structure. Each of the four or more hydrophilic functional groups may be independently selected from the group consisting of phosphate ester groups, hydroxyl groups, carboxyl groups, and thiol groups. An example of a C5-C6 aliphatic ring compound containing four or more hydrophilic functional groups in its side chain is phytic acid.

[0047] In some examples, the 4-pyrrole-containing compound can be defined as a compound containing four pyrrole structures within its molecule. The 4-pyrrole-containing compound may include, for example, any one selected from the group consisting of substituted or unsubstituted porphine; substituted or unsubstituted phthalocyanine; and combinations thereof. In this case, "substituted" may mean that at least one hydrogen atom is substituted with one or more groups selected from the group consisting of hydroxyl groups, thiol groups, and carboxyl groups. The substituted or unsubstituted porphine and substituted or unsubstituted phthalocyanine can easily form a cage structure by forming a structure in which polar functional groups containing nitrogen atoms aggregate within the ring, thereby enabling effective absorption or capture of water.

[0048] In some examples, the triazole compound having three or more hydrophilic functional groups in the side chain may include hydrophilic functional groups bonded to a linking group. Specifically, the linking group may be an aryl group, or more specifically, a phenyl group. The hydrophilic functional group linked to the triazole structure via the linking group can easily form a cage structure through molecular motion, thereby effectively absorbing or capturing water. An example of the triazole compound having three or more hydrophilic functional groups in the side chain is deferasirox.

[0049] In some examples, the phosphanic acid compound may be one or more selected from the group consisting of diethylenetriamine pentamethylenephosphonic acid (DTPPH), nitrile trimethylenephosphonic acid (NTMP), and 1-hydroxyethane-1,1-diphosphonic acid (HEDP).

[0050] In some examples, the compound containing two or more benzene rings in the molecule may be 2-methyl-6-nitrobenzoic anhydride (MNBA), 9,9-bis(4-hydroxyphenyl)fluorine (BHPF), and the like.

[0051] In some examples, the chain compound containing the amine group and the carboxyl group may be one or more selected from the group consisting of diethylenetriaminepentaacetic acid (DTPA), hydroxyaminopolycarboxylic acids (HAPCAs), and nitrilotriacetic acid (NTA).

[0052] In some examples, the crown ether compound may include a molecular structure represented by the following general formula 1 as its parent structure.

[0053] [General formula 1]

[0054] [C2H4O] n

[0055] In the general formula 1, n may be 3 to 10, and more specifically, 4 to 6. When n in the general formula 1 satisfies the above numerical range, a cage structure can be easily formed by the molecular motion of the crown ether compound.

[0056] According to yet another embodiment of the present invention, the crown ether compound may contain a hydrophilic functional group in its side chain. The hydrophilic functional group is linkable to the carbon chain of the crown ether compound. The hydrophilic functional group may be, for example, any one selected from the group consisting of a hydroxyl group, a carboxyl group, and a thiol group.

[0057] In some embodiments of the present invention, the content of the water-absorbing compound may be 0.1 to 20 parts by weight based on 100 parts by weight of the ion conductor (total solid content of the ion conductor dispersion), more specifically 0.2 to 15 parts by weight, more specifically 0.5 to 10 parts by weight, more specifically 0.5 to 7.5, 0.5 to 7.0 parts by weight, 0.5 to 6.0 parts by weight, 0.5 to 5.0 parts by weight, 0.5 to 4.0 parts by weight, 0.5 to 3.0 parts by weight, 0.5 to 2.0 parts by weight, or 0.5 to 1.0 parts by weight, preferably 0.5 to 0.7 parts by weight, and more preferably 0.5 to 0.6 parts by weight. When the content of the water-absorbing compound satisfies the above numerical range, the water content in the polymer electrolyte membrane is sufficient under high temperature and / or low humidity conditions, further improving the hydrogen ion conductivity performance, while simultaneously shortening the time to reach complete wetting.

[0058] The ion conductor contained in the ion conductor dispersion according to the present invention may be one selected from the group consisting of, for example, fluorine-based ion conductors, hydrocarbon-based ion conductors, and combinations thereof.

[0059] The ionic conductor may be a cationic conductor having a cation exchange functional group such as a hydrogen ion, or an anionic conductor having an anion exchange functional group such as a hydroxyl ion. The cation exchange functional group may be any one selected from the group consisting of a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphate group, an imide group, a sulfonimide group, a sulfonamide group, a sulfonic acid fluoride group, and combinations thereof, and is generally a sulfonic acid group or a carboxyl group. For example, the fluorine-based ionic conductor may correspond to perfluorosulfonic acid (PFSA).

[0060] The cation conductor includes the cation exchange functional group and a hydrocarbon polymer containing fluorine in the main chain, such as benzimidazole, polyamide, polyamideimide, polyimide, polyacetal, polyethylene, polypropylene, acrylic resin, polyester, polysulfone, polyether, polyetherimide, polyester, polyethersulfone, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyarylethersulfone, polyphosphazene, or polyphenylquinoxaline, a partially fluorinated polymer such as polystyrene-graft-ethylenetetrafluoroethylene copolymer or polystyrene-graft-polytetrafluoroethylene copolymer, sulfonimide, or mixtures thereof.

[0061] More specifically, when the cation conductor is a hydrogen ion cation conductor, the polymer may contain a cation exchange group in its side chain selected from the group consisting of sulfonic acid groups, carboxylic acid groups, phosphate groups, phosphonic acid groups, and derivatives thereof. Specific examples of such polymers include poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), copolymers of tetrafluoroethylene containing sulfonic acid groups and fluorovinyl ether, defluorinated sulfurized polyether ketones, or mixtures thereof.

[0062] The anion conductor is a polymer capable of transporting anions such as hydroxyl ions, and the anion conductor is commercially available in the form of a hydroxide or halide (generally a chloride), and the anion conductor can be used in industrial water purification, metal separation, or catalytic processes.

[0063] Generally, a polymer doped with a metal hydroxide can be used as the anion conductor. Specifically, metal hydroxide-doped poly(ethersulfone), polystyrene, vinyl polymers, poly(vinyl chloride), poly(vinylidene fluoride), poly(tetrafluoroethylene), poly(benzimidazole), or poly(ethylene glycol) can be used.

[0064] The hydrocarbon-based ion conductors include, for example, sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (S-PEEK), sulfonated polybenzimidazole (S-PBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene, sulfonated polyquinoxaline, sulfonated polyketone, sulfonated polyphenylene oxide, and sulfonated polyether sulfone), sulfonated polyether ketone, sulfonated polyphenylene sulfone, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone, sulfonated polyphenylene sulfide sulfone nitrile, sulfonated polyarylene ether, sulfonated polyarylene ether nitrileIt may be one selected from the group consisting of nitrile, sulfonated polyarylene ether ether nitrile, sulfonated polyarylene ether sulfone ketone, and combinations thereof.

[0065] In some examples, the solvent of the ion conductor dispersion is not particularly limited, but can be appropriately selected depending on the properties of the fluorine-based ion conductor and the hydrocarbon-based ion conductor. The solvent may include, for example, water, alcohol, and mixtures thereof.

[0066] 2.Polymer electrolyte membrane

[0067] According to one aspect of the present invention, a polymer electrolyte membrane is provided, comprising a porous support, a first ion conductor layer disposed on a first surface of the porous support, and a second ion conductor layer disposed on a second surface of the porous support opposite to the first surface, wherein the first ion conductor layer comprises an ion conductor and a water-absorbing compound, the water-absorbing compound forming a basket structure through molecular motion, and the second ion conductor layer does not contain the water-absorbing compound.

[0068] Here, the water-absorbing compound of the first ion conductor layer may include one or more of the water-absorbing compounds that can have the cage structure described above.

[0069] The water-absorbing compound not included in the second ion conductor layer is not particularly limited and may be a non-cage structure water-absorbing compound commonly used in the art, or a cage structure water-absorbing compound as described above. For example, the non-cage structure water-absorbing compound not included in the second ion conductor layer may include a super absorbent polymer, specifically one or more selected from the group consisting of sodium polyacrylate, potassium polyacrylate, polyvinyl alcohol, polyacrylamide, and polyoxyethylene. As another example, the non-cage structure water-absorbing compound not included in the second ion conductor layer may include water-absorbing inorganic particles, specifically amorphous silica particles.

[0070] The configuration of the present invention will be described in more detail below with reference to Figure 1A.

[0071] Figure 1A is a cross-sectional view of a polymer electrolyte membrane according to one embodiment of the present invention.

[0072] Referring to Figure 1A, the polymer electrolyte membrane 50 according to the present invention includes a porous support 51. For example, the ion conductor may be contained in the internal pores of the porous support 51. The polymer electrolyte membrane can be made even more durable by introducing the porous support in a reinforced composite membrane form.

[0073] The porous support 51 according to the present invention may be one selected from the group consisting of a fluorine-based porous support, a non-fluorine-based porous support, and a combination thereof.

[0074] A fluorine-based porous support according to one embodiment of the present invention may contain a highly fluorinated polymer, preferably a perfluorine polymer, which has excellent resistance to thermal and chemical decomposition, for example, polytetrafluoroethylene (PTFE) or tetrafluoroethylene and CF2=CFC n F 2n+1 (n is a real number between 1 and 5) or CF2 = CFO - (CF2CF(CF3)O)m C n F 2n+1 It may also be a copolymer of (where m is a real number from 0 to 15, and n is a real number from 1 to 15).

[0075] Other embodiments of the present invention may correspond to expanded polytetrafluoroethylene (e-PTFE) having a microstructure of polymer fibrils or a microstructure in which nodes are interconnected by fibrils. Furthermore, a film having a microstructure of polymer fibrils without the aforementioned nodes can also be used as the porous support.

[0076] A fluorinated porous support according to yet another embodiment of the present invention may include a perfluorinated polymer. The fluorinated porous support may be obtained by extruding dispersed polymerized PTFE into a tape in the presence of a lubricant, and then stretching the resulting material to obtain a more porous and stronger porous support.

[0077] Furthermore, the amorphous content of the PTFE can be increased by heat-treating the e-PTFE at a temperature exceeding the melting point of PTFE (approximately 342°C). The e-PTFE film produced by the above method may have micropores of various diameters and porosity. The e-PTFE film produced by the above method may have at least 35% micropores, and the diameter of the micropores may be approximately 0.01 to 1 μm.

[0078] A non-fluorinated porous support according to one embodiment of the present invention may be a nonwoven fibrous web consisting of a plurality of randomly oriented fibers. The nonwoven fibrous web means a sheet having the structure of individual fibers or filaments, which are interlaid but not in the same manner as woven fabrics. The nonwoven fibrous web may be manufactured by any one method selected from the group consisting of carding, garneting, air-laying, wet-laying, melt-blowing, spun-bonding, and stitch bonding.

[0079] The aforementioned fiber may contain one or more polymer materials, and generally any material used as a fiber-forming polymer material can be used. Specifically, hydrocarbon fiber-forming polymer materials can be used. For example, the fiber-forming polymer material may include any one selected from the group consisting of polyolefins, e.g., polybutylene, polypropylene and polyethylene; polyesters, e.g., polyethylene terephthalate and polybutylene terephthalate; polyamides (nylon-6 and nylon-6,6); polyurethanes; polybutene; polylactic acid; polyvinyl alcohol; polyphenylene sulfide; polysulfone; fluid crystalline polymers; polyethylene-co-vinyl acetate; polyacrylonitrile; cyclic polyolefins; polyoxymethylene; polyolefin-based thermoplastic elastic polymers; and combinations thereof. However, the technical concept of the present invention is not limited thereto.

[0080] A non-fluorinated porous support according to one embodiment of the present invention may include a nanoweb in which nanofibers are accumulated in the form of a nonwoven fabric containing numerous pores.

[0081] The nanofibers can preferably be hydrocarbon polymers that exhibit excellent chemical resistance, are hydrophobic, and are not susceptible to deformation due to moisture in high-humidity environments. Specifically, the hydrocarbon polymers can be selected from the group consisting of nylon, polyimide, polyaramid, polyetherimide, polyacrylonitrile, polyaniline, polyethylene oxide, polyethylene naphthalate, polybutylene terephthalate, styrene-butadiene rubber, polystyrene, polyvinyl chloride, polyvinyl alcohol, polyvinylbutylene, polyurethane, polybenzoxazole, polybenzimidazole, polyamideimide, polyethylene terephthalate, polyphenylene sulfide, polyethylene, polypropylene, copolymers thereof, and mixtures thereof. Among these, polyimide, which exhibits superior heat resistance, chemical resistance, and morphological stability, can be preferably used.

[0082] The nanoweb is an aggregate of nanofibers in which nanofibers manufactured by electrospinning are randomly arranged. In this case, considering the porosity and thickness of the nanoweb, it is preferable that the nanofibers have an average diameter of 40 to 5000 nm when the diameters of 50 fibers are measured using a scanning electron microscope (JSM6700F, JEOL) and the average is calculated.

[0083] If the average diameter of the nanofibers is less than the numerical range, the mechanical strength of the porous support may decrease, and if the average diameter of the nanofibers exceeds the numerical range, the porosity may decrease significantly and the thickness may increase.

[0084] The thickness of the nonwoven fibrous web may be 10 to 50 μm, and more specifically, 15 to 43 μm. If the thickness of the nonwoven fibrous web is less than the numerical range, the mechanical strength may decrease, and if it exceeds the numerical range, the resistance loss may increase, and weight reduction and integration may decrease.

[0085] The aforementioned nonwoven fiber web has a basic weight of 5-30 mg / cm². 2 This may also be the case. If the basis weight of the nonwoven fibrous web is less than the numerical range, visible pores may form, making it difficult to function as a porous support. If it exceeds the numerical range, it may be manufactured in the form of paper or fabric in which very few pores are formed.

[0086] The porosity can be calculated using the following formula 1, which is the ratio of the volume of air within the porous support to the total volume of the porous support. In this case, the total volume is calculated by manufacturing a rectangular sample and measuring its width, length, and thickness, and the volume of air is determined by measuring the mass of the sample and then subtracting the volume of polymer, which is calculated from the density, from the total volume.

[0087] [Mathematics 1]

[0088] Porosity (%) = (Volume of air in the porous support / Total volume of the porous support) × 100

[0089] The porosity of the porous support 51 according to the present invention can correspond to 30-90%, preferably 50-85%. If the porosity of the porous support is below the above numerical range, a problem of reduced impregnation of ion conductors may occur, and if it exceeds the above numerical range, the morphological stability may decrease, which may prevent subsequent processes from proceeding smoothly.

[0090] The first ion conductor layer 53a according to the present invention is disposed on the first surface of the porous support 51. Specifically, the first ion conductor layer 53a contains a water-absorbing compound that forms a cage structure through molecular motion, thereby maintaining the moisture content within the polymer electrolyte membrane under high temperature and / or low humidity conditions, while simultaneously improving ion conductivity performance. This minimizes mass transfer resistance due to excess water generated at the cathode during fuel cell operation and ensures a uniform moisture distribution within the polymer electrolyte membrane. For example, the water-absorbing compound in the first ion conductor layer may be referred to as the first water-absorbing compound.

[0091] The second ion conductor layer 53b according to the present invention is disposed on the second surface of the porous support 51 opposite to the first surface. Specifically, the first ion conductor layer 53a can be positioned opposite the second ion conductor layer 53b, and the polymer electrolyte membrane 51 may be disposed between the first and second ion conductor layers 53a and 53b.

[0092] The second ion conductor layer 53b according to the present invention does not contain a water-absorbing compound. Here, the water-absorbing compound in the second ion conductor layer 53b may be referred to as the second water-absorbing compound. If the second ion conductor layer 53b contains a water-absorbing compound, the time required to achieve the ionic conductivity performance of the polymer electrolyte membrane (time to achieve complete wetting) will be longer, which may lead to a problem in which the moisture contained in the electrolyte membrane cannot be made uniform.

[0093] The first ion conductor layer according to the present invention includes a first ion conductor, and the second ion conductor layer may include a second ion conductor.

[0094] In some embodiments of the present invention, the content of the water-absorbing compound may be 0.1 to 20 parts by weight based on 100 parts by weight of the first ion conductor (total solid content of the first ion conductor dispersion), more specifically 0.2 to 15 parts by weight, more specifically 0.5 to 10 parts by weight, more specifically 0.5 to 7.5, 0.5 to 7.0 parts by weight, 0.5 to 6.0 parts by weight, 0.5 to 5.0 parts by weight, 0.5 to 4.0 parts by weight, 0.5 to 3.0 parts by weight, 0.5 to 2.0 parts by weight, or 0.5 to 1.0 parts by weight, preferably 0.5 to 0.7 parts by weight, and more preferably 0.5 to 0.6 parts by weight. When the content of the water-absorbing compound satisfies the above numerical range, the water content in the polymer electrolyte membrane is sufficient under high temperature and / or low humidity conditions, further improving the hydrogen ion conductivity performance, while simultaneously shortening the time to reach complete wetting.

[0095] In some embodiments of the present invention, after drying in a vacuum oven at 90°C for 24 hours, the time to complete wetting of the polymer electrolyte membrane, measured at 1-minute intervals every 80 minutes after flowing 500 ccm of nitrogen for 30 minutes and then flowing 50% humidity nitrogen at the same flow rate, may be 64 minutes or less, 61 minutes or less, 58 minutes or less, 57 minutes or less, or 52 minutes or less, and specifically, it may be within a range with an upper limit of any one of the above values ​​of 50 minutes or more. Here, the time to complete wetting is the time at which the ionic conductivity of the polymer electrolyte membrane becomes saturated. By satisfying the above numerical range for the time to complete wetting, the moisture absorption capacity of the polymer electrolyte membrane can be further improved.

[0096] In some embodiments of the present invention, the water content of the polymer electrolyte membrane measured at 80°C and 50%RH may be 4.8% or more, 5.0% or more, 5.4% or more, 5.5% or more, 5.7% or more, 5.8% or more, 6.0% or more, 6.5% or more, 7.0% or more, or 7.3% or more, and specifically, it may be within a range where one of the above values ​​is the lower limit and 8% or less is the upper limit. By satisfying the above numerical range for the water content of the polymer electrolyte membrane, the moisture absorption capacity of the polymer electrolyte membrane can be further improved.

[0097] 3. Membrane-electrode assembly

[0098] Figure 1B is a cross-sectional view showing a film-electrode assembly according to one embodiment of the present invention.

[0099] Referring to Figures 1A and 1B, yet another embodiment of the present invention provides a membrane-electrode assembly 100 including the polymer electrolyte membrane 50. The membrane-electrode assembly 100 according to the present invention includes an anode 20, a cathode 20', and a polymer electrolyte membrane 50 of some embodiments disposed between the anode 20 and the cathode 20'. Specifically, the first ion conductor layer 53a is in contact with the anode 20. By arranging the first ion conductor layer in contact with the anode, the moisture content within the polymer electrolyte membrane can be maintained under high temperature and / or low humidity conditions, thereby improving ionic conductivity performance, and moisture generated at the cathode during fuel cell operation can be absorbed to create a uniform moisture distribution within the polymer electrolyte membrane.

[0100] In some examples, the thicknesses of the first and second ion conductor layers 53a and 53b may be independently 0.5 to 40 μm, more specifically 1 to 30 μm, and more specifically 1 to 20 μm. When the thicknesses of the first and second ion conductor layers satisfy the above numerical range, moisture generated in the cathode during operation of the fuel cell can be absorbed, and the moisture distribution within the polymer electrolyte membrane can be made sufficiently uniform.

[0101] When the anode 20 and cathode 20' are both referred to as electrodes, the electrodes 20, 20' include electrode substrates 40, 40' and catalyst layers 30, 30' formed on the surfaces of the electrode substrates 40, 40'. A fine-porous layer (not shown) containing conductive fine particles such as carbon powder or carbon black may be further included between the electrode substrates 40, 40' and the catalyst layers 30, 30' to facilitate the diffusion of substances in the electrode substrates 40, 40'.

[0102] In the membrane-electrode assembly 100, the electrode 20, which is placed on one surface of the polymer electrolyte membrane 50 and causes an oxidation reaction to generate hydrogen ions and electrons from the fuel transmitted to the catalyst layer 30 via the electrode substrate 40, is called the anode electrode.

[0103] An electrode 20', positioned on the other side of the polymer electrolyte membrane 50, which causes a reduction reaction to generate water from hydrogen ions supplied through the polymer electrolyte membrane 50 and an oxidizing agent transmitted to the catalyst layer 30' via the electrode substrate 40', is called a cathode electrode.

[0104] The catalyst layers 30, 30' of the anode and cathode electrodes 20, 20' contain a catalyst. Any catalyst that participates in the battery reaction and is typically usable as a catalyst in a fuel cell can be used. Preferably, a platinum-based metal can be used.

[0105] The platinum-based metal may include one selected from the group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), osmium (Os), platinum-M alloys, non-platinum alloys, and combinations thereof. More preferably, a combination of two or more metals selected from the group of platinum-based catalyst metals can be used, but is not limited thereto. Any platinum-based catalyst metal usable in the art can be used without restriction.

[0106] The aforementioned M can correspond to one or more elements selected from the group consisting of palladium (Pd), ruthenium (Ru), iridium (Ir), osmium (Os), gallium (Ga), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), silver (Ag), gold (Au), zinc (Zn), tin (Sn), molybdenum (Mo), tungsten (W), lanthanum (La), and rhodium (Rh). Specifically, the platinum alloy can be selected from the group consisting of Pt-Pd, Pt-Sn, Pt-Mo, Pt-Cr, Pt-W, Pt-Ru-W, Pt-Ru-Mo, Pt-Ru-Rh-Ni, Pt-Ru-Sn-W, Pt-Co, Pt-Co-Ni, Pt-Co-Fe, Pt-Co-Ir, Pt-Co-S, Pt-Co-P, Pt-Fe, Pt-Fe-Ir, Pt-Fe-S, Pt-Fe-P, Pt-Au-Co, Pt-Au-Fe, Pt-Au-Ni, Pt-Ni, Pt-Ni-Ir, Pt-Cr-Ir, and combinations thereof, either individually or in mixtures of two or more.

[0107] Furthermore, the non-platinum alloy can be selected from the group consisting of Ir-Fe, Ir-Ru, Ir-Os, Co-Fe, Co-Ru, Co-Os, Rh-Fe, Rh-Ru, Rh-Os, Ir-Ru-Fe, Ir-Ru-Os, Rh-Ru-Fe, Rh-Ru-Os, and combinations thereof, either individually or in mixtures of two or more.

[0108] The catalyst may be used as the catalyst itself (black), or it may be supported on a carrier.

[0109] 4.Fuel cell

[0110] Figure 2 is a schematic diagram showing a fuel cell according to one embodiment of the present invention.

[0111] A further embodiment of the present invention provides a fuel cell comprising the membrane-electrode assembly.

[0112] Referring to Figure 2, the fuel cell 200 according to the present invention may include a fuel supply unit 210 that supplies a mixed fuel of fuel and water, a reforming unit 220 that reforms the mixed fuel to generate a reformed gas containing hydrogen gas, a stack 230 in which the reformed gas containing hydrogen gas supplied from the reforming unit 220 undergoes an electrochemical reaction with an oxidizer to generate electrical energy, and an oxidizer supply unit 240 that supplies an oxidizer to the reforming unit 220 and the stack 230.

[0113] The stack 230 may comprise a plurality of unit cells that generate electrical energy by inducing an oxidation / reduction reaction between a reformed gas containing hydrogen gas supplied from the reforming unit 220 and an oxidant supplied from the oxidant supply unit 240.

[0114] Each unit cell refers to a cell that generates electricity and may include a membrane-electrode assembly that oxidizes / reduces oxygen in a reformed gas containing hydrogen gas and an oxidizer, and a separation plate (also called a bipolar plate, hereinafter referred to as "separation plate") for supplying the reformed gas containing hydrogen gas and the oxidizer to the membrane-electrode assembly. The separation plates are positioned on both sides of the membrane-electrode assembly, which is placed in the center. In this case, the separation plates located on the outermost sides of the stack are sometimes specifically referred to as end plates.

[0115] One of the separation plates, the end plate, is provided with a pipe-shaped first supply pipe 231 for injecting reformed gas containing hydrogen gas supplied from the reforming unit 220, and a pipe-shaped second supply pipe 232 for injecting oxygen gas. Another end plate may be provided with a first discharge pipe 233 for discharging reformed gas containing hydrogen gas that remains unreacted in multiple unit cells to the outside, and a second discharge pipe 234 for discharging unreacted oxidizer that remains unreacted in the unit cells to the outside.

[0116] In the aforementioned fuel cell, the separator, fuel supply unit, and oxidizer supply unit constituting the electricity generation unit are those used in ordinary fuel cells, so a detailed explanation is omitted in this specification.

[0117] The following describes in detail embodiments of the present invention so that those with ordinary skill in the art to which the present invention pertains can easily implement it. However, this is merely an example, and the scope of the rights of the present invention is not limited to the following.

[0118] [Manufacturing Example 1: Manufacturing of Ion Conductor Compositions]

[0119] Ion conductor compositions were prepared according to the compositions shown in Table 1 below. In Table 1 below, the content of the water-absorbing compound was set as the relative content to 100 parts by weight of the total solids (ion conductor) of the ion conductor dispersion.

[0120] [Table 1]

[0121] [Manufacturing Example 2: Manufacturing of Polymer Electrolyte Membranes (Reinforced Composite Membranes)] <Comparative Example 1: Commercial Reinforced Composite Membranes that Do Not Contain Water-Absorbing Compounds>

[0122] After coating a substrate (film or glass plate) with the ion conductor dispersion according to Comparative Preparation Example 1, a PTFE support (80% porosity; 0.45 μm pore size; 10 μm thickness) was covered and impregnated at room temperature for 60 minutes. Subsequently, the ion conductor dispersion according to Comparative Preparation Example 1 was additionally applied to the opposite side of the coated PTFE, and then dried at 120°C for 30 minutes to produce a polymer electrolyte membrane (or reinforced composite membrane) with a total thickness of 20 μm.

[0123] <Comparative Example 2: Reinforced composite film containing water-absorbing compounds on both surfaces and within the reinforced composite film>

[0124] A reinforced composite film was manufactured in the same manner as in Comparative Example 1, and the ion conductor composition of Implementation Example 1 was used instead of the ion conductor composition of Comparative Preparation Example 1. As a result, dried ion conductor layers (each with a thickness of 3 μm) of the ion conductor composition of Implementation Example 1 were formed on both sides of the reinforced composite film, and the ion conductor composition of Implementation Example 1 was impregnated into the internal pores of the porous support. Thus, the ion conductor layers introduced on both sides of the reinforced composite film can come into contact with the anode and cathode, respectively, in the film-electrode assembly manufacturing process described later.

[0125] On the other hand, in Comparative Example 2, each ion conductor layer can be in contact with both the anode and the cathode, and is therefore indicated as Anode + Cathode in Table 1 below.

[0126] <Examples 1-6: Reinforced composite film in which an ion conductor layer containing a water-absorbing compound is arranged on only one surface of the reinforced composite film>

[0127] A reinforced composite film was manufactured using the same method as in Comparative Example 1, but the impregnation time was changed from 1 hour to 30 minutes to form a preliminary reinforced composite film in which a second ion conductor layer that does not contain a water-absorbing compound was arranged on only one side of the reinforced composite film.

[0128] On the other surface of the pre-reinforced composite film facing the one surface, a dried ion conductor layer (each with a thickness of 3 μm) using the ion conductor composition (containing a water-absorbing compound) according to the preparation examples 1 to 6 is laminated using a lamination method (pressure 0.4 kgf / cm²). 2 After coating at 80°C for 10 minutes, the first ion conductor layer (thickness: 3 μm) was formed by drying at 120°C for 30 minutes.

[0129] [Table 2]

[0130] [Experimental example: Evaluation experiment of ionic conductivity, low-humidity moisture content, and dimensional stability]

[0131] 1) Ionic conductivity (high temperature / low humidity conditions; 80°C / 50%RH) and time to complete humidification (min)

[0132] Ionic conductivity

[0133] After directly coating both sides of a reinforced composite film manufactured by the method described in Manufacturing Example 1 with an electrode slurry (weight ratio of Pt / C and PFSA binder = 1:0.35 (w / w)), and then drying it, the ionic conductivity of the resulting film-electrode assembly was measured at a measurement temperature of 80°C using a measuring device (Scriber MTS-740). Specifically, after measuring the ohmic resistance or bulk resistance using the four-point probe AC ​​impedance spectroscopic method, the ionic conductivity was calculated using the following formula 2.

[0134] [Math 2]

[0135] σ = L / RS

[0136] In the above equation 2, σ is the ionic conductivity (S / cm), R is the ohmic resistance of the electrolyte membrane (Ω), L is the distance between electrodes (cm), and S is the area within the electrolyte through which a constant current flows (cm²). 2 )

[0137] Time to reach complete wetness

[0138] At this time, in order to limit the location to which humidity is supplied, one side of the film (polymer electrolyte membrane) was adjusted to be completely attached. In this case, it was dried in a 90°C vacuum oven for 24 hours. After the dried electrolyte membrane was placed in the ion conductivity cell, 500 ccm of nitrogen was flowed through it for 30 minutes in a completely dry state. Thereafter, nitrogen at 50% humidity was flowed at the same flow rate, and the ion conductivity was measured at 1-minute intervals every 80 minutes to measure the time it took for the ion conductivity to saturate, and the time it took for the polymer electrolyte membrane to reach wet equilibrium was measured. At this time, if the time to reach complete wetness was less than 65 min, the moisture absorption capacity of the polymer electrolyte membrane could be evaluated as having improved compared to the existing state.

[0139] 2) Low humidity moisture content (high temperature / low humidification conditions; 80℃ / 50%RH)

[0140] The polymer electrolyte membrane from manufacturing example 1 was washed several times with deionized water, and the washed polymer electrolyte membrane was dried in a vacuum dryer at 90°C for 24 hours, after which its weight was measured (W dry Next, the same membrane was left to stand in a chamber at 80°C and 50%RH for 4 hours, and then its weight was measured in the chamber (W wet Subsequently, the low-humidity moisture content was calculated using the following formula 3. When the moisture content range is 4.8% or higher under high temperature and low humidity conditions, it can be said that the membrane-electrode assembly has excellent performance.

[0141] [Math 3]

[0142] Water absorption rate (water uptake, %) = [(W wet -W dry ) / (W dry )] × 100

[0143] [Table 3]

[0144] As shown in Table 3 above, comparing Comparative Example 1 and Example 1 in terms of the ionic conductivity of the polymer electrolyte membrane with and without the water-absorbing compound, the polymer electrolyte membrane in Example 1, in which the water-absorbing compound was applied only to the first ion conductor layer, showed higher water absorption, lower humidity, and higher ionic conductivity compared to the polymer electrolyte membrane without the water-absorbing compound (Comparative Example 1). This resulted in a shorter time to complete wetting and an effect of uniformly adjusting the moisture distribution of the polymer electrolyte membrane. Comparing Comparative Example 2 and Example 1 in terms of the time to complete wetting depending on the application position of the water-absorbing compound, Comparative Example 2, in which the water-absorbing compound was applied to both the first and second ion conductor layers, showed slightly higher ionic conductivity than Example 1, in which the water-absorbing compound was applied only to the first ion conductor layer. However, it showed the problem of a relatively longer time to complete wetting, indicating that it was difficult to uniformly adjust the moisture distribution within the electrolyte membrane. In contrast, Example 1, by applying the water-absorbing compound only to the first ion conductor layer, showed the effect of raising the ionic conductivity to an appropriate level while simultaneously shortening the time to complete wetting and uniformly adjusting the moisture distribution.

[0145] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art that utilize the basic concepts of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

1. A porous support, A first ion conductor layer disposed on the first surface of the porous support, The porous support comprises a second ion conductor layer disposed on a second surface opposite to the first surface of the porous support, The first ion conductor layer is It contains an ion conductor and a water-absorbing compound, The water-absorbing compound forms a basket structure through molecular motion. The second ion conductor layer is Free from water-absorbing compounds, Polymer electrolyte membrane.

2. The water-absorbing compound of the first ion conductor layer is A compound comprising at least one of the following: hexadentate ligands; aliphatic ring compounds with 5-6 carbon atoms containing 4 or more hydrophilic functional groups in their side chains; 4-pyrrole containing compounds; triazole compounds containing 3 or more hydrophilic functional groups in their side chains; phosphanic acid compounds; compounds containing 2 or more benzene rings in their molecule; chain compounds containing amine and carboxyl groups; and crown ether compounds. The polymer electrolyte membrane according to claim 1.

3. The aforementioned hexadentate ligand is One selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), and combinations thereof. The polymer electrolyte membrane according to claim 2.

4. A C5-C6 aliphatic ring compound containing four or more hydrophilic functional groups in its side chain is, Contains phytic acid, The polymer electrolyte membrane according to claim 2.

5. The 4-pyrrole-containing compound is A compound comprising any one selected from the group consisting of substituted or unsubstituted porphine; substituted or unsubstituted phthalocyanine; and combinations thereof. The polymer electrolyte membrane according to claim 2.

6. The triazole compound having three or more hydrophilic functional groups in the side chain is Contains deferasirox The polymer electrolyte membrane according to claim 2.

7. The aforementioned crown ether compound is The parent structure includes the molecular structure represented by the following general formula 1, The polymer electrolyte membrane according to claim 2: [General formula 1] [C ２ H ４ O] ｎ In the above general formula 1, n is between 3 and 10.

8. The ion conductor is contained in the internal pores of the porous support. The polymer electrolyte membrane according to claim 1.

9. A-scatter, Cathode and, The polymer electrolyte membrane according to claim 1, disposed between the anode and the cathode, The first ion conductor layer is in contact with the anode. Membrane-electrode assembly.

10. A fuel cell comprising the membrane-electrode assembly according to claim 9.

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