Polymer electrolyte membrane, membrane-electrode assembly, and fuel cell comprising same

Abstract

Disclosed is a polymer electrolyte membrane having improved ion conductivity performance by maintaining the moisture content therein under high temperature and / or low humidity conditions. According to one aspect, the polymer electrolyte membrane comprises: 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, the first ion conductor layer containing an ion conductor and an absorbent compound, wherein the absorbent compound forms a basket structure by molecular motion, and the second ion conductor layer contains no absorbent compound.

Description

Polymer electrolyte membrane, membrane-electrode assembly and fuel cell including the same

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

[0002] A fuel cell is a battery that directly converts chemical reaction energy, such as oxidation / reduction reactions of hydrogen and oxygen contained in hydrocarbon fuels such as methanol, ethanol, and natural gas, into electrical energy. Due to its high energy efficiency and environmentally friendly characteristics of low pollutant emissions, it is attracting attention as a next-generation clean energy source that can replace fossil fuels. Fuel cells can be classified into alkaline electrolyte membrane fuel cells and polymer electrolyte membrane fuel cells (PEMFC) depending on the state and type of electrolyte. Among them, polymer electrolyte membrane fuel cells are attracting attention as a power source for portable, automotive, and home use due to their advantages such as low operating temperature of less than 100℃, fast start-up and response characteristics, and excellent durability. Representative examples of polymer electrolyte membrane fuel cells include the Proton Exchange Membrane Fuel Cell (PEMFC), which uses hydrogen gas as fuel, and the Direct Methanol Fuel Cell (DMFC), which uses liquid methanol as fuel.

[0003] To summarize the reactions occurring in a polymer electrolyte membrane fuel cell, first, when a fuel such as hydrogen gas is supplied to the anode electrode, hydrogen ions (H) are produced by the oxidation reaction of hydrogen gas at the anode electrode. + ) 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 oxygen combines with hydrogen ions and electrons to produce water through a reduction reaction of oxygen.

[0004] Meanwhile, many technological hurdles remain to be overcome to commercialize polymer electrolyte membrane fuel cells. Essential improvements include achieving high performance, long life, and low cost. The component that most significantly influences these improvements is the membrane-electrode assembly, and among them, the polymer electrolyte membrane is one of the key elements that most significantly influences the performance and cost of the MEA. Requirements for polymer electrolyte membranes required for the operation of polymer electrolyte membrane fuel cells include high proton conductivity, chemical stability, low fuel permeability, high mechanical strength, and excellent dimensional stability. Conventional polymer electrolyte membranes tend to struggle to perform normally under certain temperature and relative humidity conditions, particularly at high temperatures or low humidity. Consequently, polymer electrolyte membrane fuel cells employing conventional polymer electrolyte membranes face limitations in their scope of application.

[0005] In order to overcome the problem of difficulty in demonstrating high performance of polymer electrolyte membranes, especially 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 membranes.

[0006] An object of the present invention is to provide a polymer electrolyte membrane that improves ionic conductivity performance by maintaining the moisture content within the polymer electrolyte membrane under high temperature and / or low humidity conditions.

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

[0008] Another object of the present invention is to provide a polymer electrolyte membrane that minimizes anodic drying at the anode due to insufficient water and moisture, water flooding at the cathode due to excessive water and moisture, and mass transport resistance caused by the aforementioned phenomena.

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

[0010] Another object of the present invention is to provide a fuel cell including the membrane-electrode assembly.

[0011] The purposes of the present invention are not limited to those mentioned above, and other unmentioned purposes and advantages of the present invention can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the purposes and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0012] According to a first aspect of the present invention for achieving the above object, a polymer electrolyte membrane is provided, comprising: a porous support; a first ion conductor layer disposed on a first side of the porous support; and a second ion conductor layer disposed on a second side of the porous support opposite the first side, wherein the first ion conductor layer includes an ion conductor and an absorbent compound, wherein the absorbent compound forms a basket structure through molecular motion, and the second ion conductor layer does not include an absorbent compound.

[0013] According to a second aspect of the present invention, in the first aspect, the absorbent compound of the first ion conductor layer may include at least one of a hexadentate ligand; an aliphatic ring compound having 5 to 6 carbon atoms containing 4 or more hydrophilic functional groups in a side chain; a 4-pyrrole containing compound; a triazole compound containing 3 or more hydrophilic functional groups in a side chain; a phosphonic acid compound; a compound containing 2 or more benzene rings in a molecule; a chain-like 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 the fourth aspect of the present invention, the aliphatic ring compound having 5 to 6 carbon atoms and containing 4 or more hydrophilic functional groups in the side chain in the second or third aspect may 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 may 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, the triazole compound containing three or more hydrophilic functional groups in the side chain in any one of the second to fifth aspects may 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 may include a molecular structure represented by the following general formula 1 as a parent.

[0019] [General Formula 1]

[0020] [C2H4O] n

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

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

[0023] According to a ninth aspect of the present invention, a membrane-electrode assembly is provided, comprising: 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 a tenth aspect of the present invention, a fuel cell is provided comprising a membrane-electrode assembly according to the ninth aspect.

[0025] The solutions to the above problems are not exhaustive and may be combined with several embodiments of the present disclosure. The various features of the present invention and their corresponding advantages and effects can be understood in more detail by referring to the detailed description below.

[0026] According to one aspect of the present invention, it is possible to improve ion conductivity performance by maintaining the moisture content in a polymer electrolyte membrane under high temperature and / or low humidity conditions, absorb moisture generated at a cathode during fuel cell operation to evenly distribute moisture within the polymer electrolyte membrane, and reduce mass transport resistance formed by excess water generated at the cathode.

[0027] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

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

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

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

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

[0032] The numerical range indicated by the term "to" in this specification refers to a numerical range that includes the values ​​described before and after the term as the lower limit and the upper limit, respectively. When multiple numerical values ​​are disclosed as the upper and lower limits of any numerical range, the numerical range disclosed in this specification can be understood as any numerical range that has any one of the multiple lower limit values ​​and any one of the multiple upper limit values ​​as the lower limit and the upper limit, respectively. For example, when the specification describes a to b, or c to d, it can be understood that a or more and b or less, a or more and d or less, c or more and d or less, or c or more and b or less is described.

[0033] In this specification, “At least one of a, b and c” may include a, b or c alone, or a combination of two or more selected from the group consisting of a, b and c.

[0034] In this specification, the term “layer” or film may include cases where it is formed not only over the entire area when observing the area where the layer or film exists, but also cases where it is formed over only a portion of the area. For example, the surface of the layer or film may be defined to include a flat shape, a non-flat shape, and a combination thereof; or a continuous shape, a discontinuous shape, and a combination thereof. For example, when another member is formed as a layer or film directly on top of one member, the coverage of the other member on the surface of the one 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, even when a plurality of particles form a clustered structure, it may be defined as a “layer or “film.”

[0035] As used herein, “substituted” means a group in which at least one hydrogen atom is substituted with a halogen atom, a hydroxyl 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, a C1 to C 30 Alkyl group of C2 to C 30 Alkenyl group, C2 to C 30 Alkynyl group, C1 to C 40 Alkylsilyl group, C5 to C 40 Arylsilyl group, C3 to C 30 Cycloalkyl group, C3 to C 30Allyl group, C6 to C 30 Aryl group, heterocyclic group (e.g. C2 to C) 30 Heterocycloalkyl group, C3 to C 30 is defined as being replaced by any one selected from the group consisting of heteroaryl groups, derivatives thereof, and combinations thereof. Here, each of the above substituents may combine with each other when adjacent to each other to form a substituted or unsubstituted fused ring or spiro structure.

[0036] In this specification, “fused ring” means a ring in which two or more rings are joined by sharing two or more atoms, and may include, for example, a fused aliphatic ring, a fused aromatic ring, a fused heteroaliphatic ring, a fused heteroaromatic ring, or a combination thereof.

[0037] As used herein, “spiro structure” means a structure having a spiro union, which means a connection formed by two rings sharing only one atom.

[0038] In this specification, the term 'basket structure' refers to a structure that forms a basket structure through molecular motion, and specifically, a structure in which a part of a molecule can become closer to or further away from another part of the molecule through molecular motion, and more specifically, a structure that forms a basket shape when a part of a molecule becomes closer to another part of the molecule. For example, the basket structure may refer to a structure in which a non-shared electron pair in a molecule can form a coordinate bond or an ionic bond with a metal or a metal ion, or may refer to a structure in which a non-shared electron pair in a molecule can interact with a metal or a metal ion to form a complex compound. As a quantitative analysis method for determining whether or not it is the basket structure, any one method selected from the group consisting of FT-IR (Fourier transform infrared) Spectrometer), NMR (Nuclear Magnetic Resonance), Raman spectroscopy, XRD (X-ray diffraction), MD Simulation, or a combination thereof may be used. For example, when the above-mentioned absorbent compound forms a basket structure by molecular motion, the shortest distance between the nearest 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 through an analysis method of X-ray diffraction or MD simulation.

[0039] One embodiment of the present invention provides an ion conductor composition comprising an ion conductor and an absorbent compound, wherein the absorbent compound forms a basket structure through molecular motion. According to one aspect of the present invention, by using the absorbent compound that forms a basket structure through molecular motion, the moisture content in a polymer electrolyte membrane can be maintained under high temperature and / or low humidity conditions, thereby improving ion conductivity performance, and by absorbing excess water molecules generated at a cathode during fuel cell operation, the moisture distribution in the polymer electrolyte membrane can be evenly maintained, and mass transport resistance caused by excess water can be minimized.

[0040] Below, the configuration of the present invention is described in more detail.

[0041] 1. Ionic conductor composition

[0042] The ion conductor composition according to the present invention may include an ion conductor dispersion and an absorbent compound.

[0043] The absorbent 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 fuel cell operation, thereby maintaining the moisture content within the polymer electrolyte membrane even under high temperature and / or low humidity conditions. By introducing the compound forming the basket structure, the ion conductivity performance of the polymer electrolyte membrane can be improved, and moisture generated at the cathode during fuel cell operation can be effectively absorbed, thereby evenly distributing moisture within the polymer electrolyte membrane.

[0044] The absorbent compound according to the present invention may include at least one of a hexadentate ligand; an aliphatic ring compound having 5 to 6 carbon atoms and containing 4 or more hydrophilic functional groups in a side chain; a 4-pyrrole-containing compound; a triazole-based compound having 3 or more hydrophilic functional groups in a side chain; a phosphonic acid-based compound; a compound containing two or more benzene rings in a molecule; a chain-like compound containing an amine group and a carboxyl group; and a crown ether-based compound. Specifically, the absorbent compound may include a 4-pyrrole-containing compound, and more specifically, a substituted or unsubstituted porphine. Here, the 4-pyrrole-containing compound has a relatively superior water capturing ability compared to other types of basket-structured compounds, and thus may further increase the ionic conductivity of the membrane-electrode assembly, improve the moisture retention ability, and increase the moisture content even under high temperature and low humidity conditions.

[0045] In some examples, the six-dentate ligand can effectively absorb or capture water by easily forming a basket structure due to the attractive and repulsive forces between electron pairs. Since the basket structure is easily formed by molecular motion, the ion conductivity performance of the polymer electrolyte membrane can be improved, and moisture generated at the cathode during fuel cell operation can be absorbed to evenly distribute moisture within the polymer electrolyte membrane. The six-dentate ligand may be, for example, any one selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), and combinations thereof.

[0046] In some examples, the alicyclic compound having 5 to 6 carbon atoms and containing 4 or more hydrophilic functional groups in the side chain can easily form a basket structure by forming intramolecular hydrogen bonds between the 4 or more hydrophilic functional groups through molecular motion. That is, the alicyclic compound may include cyclopentane or cyclohexane as a parent molecule, and the side chains may all be substituted with hydrophilic functional groups to easily form a basket structure. The 4 or more hydrophilic functional groups may each independently be any one selected from the group consisting of a phosphate ester group, a hydroxyl group, a carboxyl group, and a thiol group. The alicyclic compound having 5 to 6 carbon atoms and containing 4 or more hydrophilic functional groups in the side chain may include, for example, phytic acid.

[0047] In some examples, the 4-pyrrole containing compound may be defined as a compound containing four pyrrole structures in the 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 is replaced with any one or more selected from the group consisting of a hydroxyl group, a thiol group, and a carboxyl group. The substituted or unsubstituted porphine; or substituted or unsubstituted phthalocyanine can easily form a basket structure by forming a structure in which a polar functional group containing a nitrogen atom is aggregated within the ring, thereby effectively absorbing or capturing water.

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

[0049] In some examples, the phosphonic acid compound may be at least one selected from the group consisting of diethylenetriamine pentamethylenephosphonic acid (DTPPH), nitriletrimethylenephosphonic acid (NTMP), and 1-hydroxyethane-1,1-diphosphonic acid (HEDP).

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

[0051] In some examples, the chain compound containing the amine group and the carboxyl group may be at least one 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 a parent compound.

[0053] [General Formula 1]

[0054] [C2H4O] n

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

[0056] According to another embodiment of the present invention, the crown ether compound may include a hydrophilic functional group in the side chain. The hydrophilic functional group may be linked to a 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 absorbent 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), 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, and preferably 0.5 to 0.7 parts by weight, more preferably 0.5 to 0.6 parts by weight. When the content of the above absorbent compound satisfies the above numerical range, the moisture content in the polymer electrolyte membrane is sufficient under high temperature and / or low humidity conditions, so that the hydrogen ion conductivity performance can be further improved, and at the same time, the time to reach complete wetting can be shortened.

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

[0059] The ion conductor may be a cation conductor having a cation exchange functional group such as a hydrogen ion, or an anion conductor having an anion exchange functional group such as a hydroxy 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 phosphoric acid group, an imide group, a sulfonimide group, a sulfonamide group, a sulfonic acid fluoride group, and combinations thereof, and may generally be a sulfonic acid group or a carboxyl group. For example, the fluorine-based ion conductor may correspond to perfluorosulfonic acid (PFSA).

[0060] The above cation conductor includes the cation exchange functional group, and may include hydrocarbon polymers such as fluorine-containing polymers, 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, partially fluorinated polymers such as polystyrene-graft-ethylenetetrafluoroethylene copolymer or polystyrene-graft-polytetrafluoroethylene copolymer, sulfone imide or mixtures thereof.

[0061] More specifically, when the cation conductor is a hydrogen ion cation conductor, the polymers may include a cation exchange group selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a phosphonic acid group, and derivatives thereof in the side chain, and specific examples thereof may include poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), a copolymer of tetrafluoroethylene and fluorovinyl ether containing a sulfonic acid group, a defluorinated sulfurized polyether ketone, or a fluorinated polymer including a mixture thereof.

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

[0063] As the above anion conductor, a polymer doped with a metal hydroxide can generally be used, and specifically, poly(ethersulfone), polystyrene, vinyl polymer, poly(vinyl chloride), poly(vinylidene fluoride), poly(tetrafluoroethylene), poly(benzimidazole), or poly(ethylene glycol) doped with a metal hydroxide 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, sulfonated polyethersulfone, sulfonated Sulfonated polyether ketone, sulfonated polyphenylene sulfone, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone, sulfonated polyphenylene sulfide sulfone nitrile, sulfonated polyarylene ether, sulfonated polyarylene ether nitrile, sulfonated polyarylene ether ether nitrile,It may be one selected from the group consisting of sulfonated polyarylene ether sulfone ketone and combinations thereof.

[0065] In some examples, the solvent of the ion conductor dispersion is not particularly limited, but may be appropriately selected depending on the characteristics 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 the first surface, wherein the first ion conductor layer includes an ion conductor and an absorbent compound, wherein the absorbent compound forms a basket structure through molecular motion, and the second ion conductor layer does not include an absorbent compound.

[0068] Here, the absorbent compound of the first ion conductor layer may include at least one of the absorbent compounds that may have the above-described basket structure.

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

[0070] Hereinafter, the configuration of the present invention will be described in more detail with reference to Fig. 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 Fig. 1a, the polymer electrolyte membrane (50) according to the present invention includes a porous support (51). For example, the ion conductor may be included in the internal pores of the porous support (51). The polymer electrolyte membrane may be further enhanced in durability by introducing the porous support in the form of a reinforced composite membrane.

[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] The fluorine-based porous support according to one embodiment of the present invention may include a highly fluorinated polymer, preferably a perfluorinated polymer, having excellent resistance to thermal and chemical degradation, for example, polytetrafluoroethylene (PTFE) or tetrafluoroethylene and CF2=CFC.n F 2n+1 (n is a real number from 1 to 5) or CF2=CFO-(CF2CF(CF3)O) m C n F 2n+1 (m is a real number from 0 to 15, n is a real number from 1 to 15) may be a copolymer.

[0075] According to another embodiment of the present invention, a fluorine-based porous support may correspond to expanded polytetrafluoroethylene (e-PTFE) having a microstructure of polymer fibrils or a microstructure in which nodes are interconnected by fibrils. In addition, a film having a microstructure of polymer fibrils without nodes may also be used as the porous support.

[0076] According to another embodiment of the present invention, a fluorinated porous support may comprise a perfluorinated polymer. The fluorinated porous support may be formed by extruding dispersed polymerized PTFE into a tape in the presence of a lubricant, and then stretching the resulting material to form a more porous and stronger porous support.

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

[0078] According to one embodiment of the present invention, a non-fluorinated porous support may be a nonwoven fibrous web composed of a plurality of randomly oriented fibers. The nonwoven fibrous web refers to a sheet having a structure of individual fibers or filaments that are interlaid, but not in the same manner as a woven fabric. 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, spunbonding, and stitch bonding.

[0079] The fiber may comprise one or more polymer materials, and any material that is generally used as a fiber-forming polymer material may be used, and specifically, a hydrocarbon-based fiber-forming polymer material may be used. For example, the fiber-forming polymer material may comprise any one selected from the group consisting of polyolefins such as polybutylene, polypropylene, and polyethylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides (nylon-6 and nylon-6,6), polyurethanes, polybutenes, polylactic acid, polyvinyl alcohol, polyphenylene sulfide, polysulfones, fluid crystalline polymers, polyethylene-co-vinylacetate, polyacrylonitrile, cyclic polyolefins, polyoxymethylene, polyolefin-based thermoplastic elastomers, and combinations thereof. However, the technical idea of ​​the present invention is not limited thereto.

[0080] A non-fluorine-based porous support according to one embodiment of the present invention may include a nanoweb in which nanofibers are integrated in the form of a non-woven fabric including a plurality of pores.

[0081] The above nanofibers exhibit excellent chemical resistance and are hydrophobic, and thus can preferably use hydrocarbon polymers that are not susceptible to deformation due to moisture in high-humidity environments. Specifically, the hydrocarbon polymers may 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, polyvinyl butylene, polyurethane, polybenzoxazole, polybenzimidazole, polyamideimide, polyethylene terephthalate, polyphenylene sulfide, polyethylene, polypropylene, copolymers thereof, and mixtures thereof. Among these, polyimide having superior heat resistance, chemical resistance, and dimensional stability can be preferably used.

[0082] The above nanoweb is a collection of nanofibers manufactured by electrospinning and arranged randomly. At this time, the nanofibers preferably have an average diameter of 40 to 5000 nm when the average diameter of 50 fibers is measured using a scanning electron microscope (JSM6700F, JEOL) and calculated from the average, taking into account the porosity and thickness of the nanoweb.

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

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

[0085] The above nonwoven fibrous web has a basic weight of 5 to 30 mg / cm 2 If the basis weight of the nonwoven fibrous web is less than the above numerical range, visible pores may be formed, making it difficult to function as a porous support, and if it exceeds the above numerical range, it may be manufactured in the form of paper or fabric in which pores are hardly formed.

[0086] The above porosity can be calculated by the ratio of the air volume within the porous support to the total volume of the porous support according to the following mathematical formula 1. At this time, the total volume is calculated by manufacturing a rectangular sample and measuring the width, length, and thickness, and the air volume can be obtained by measuring the mass of the sample and then subtracting the polymer volume calculated inversely from the density from the total volume.

[0087] [Mathematical Formula 1]

[0088] Porosity (%) = (air volume in porous support / total volume of porous support) X 100

[0089] The porosity of the porous support (51) according to the present invention may be 30 to 90%, and preferably 50 to 85%. If the porosity of the porous support is below the above numerical range, the problem of reduced impregnation of the ion conductor may occur, and if it exceeds the above numerical range, the shape stability may be reduced, preventing 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) includes an absorbent compound that forms a basket structure through molecular motion, thereby maintaining the moisture content in the polymer electrolyte membrane under high temperature and / or low humidity conditions while improving ion conductivity performance, minimizing mass transfer resistance caused by excessive water generated at the cathode during fuel cell operation, and evenly distributing moisture in the polymer electrolyte membrane. For example, the absorbent compound of the first ion conductor layer may be referred to as a first absorbent 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) may 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, 53b).

[0092] The second ion conductor layer (53b) according to the present invention does not include an absorbent compound. Here, the absorbent compound of the second ion conductor layer (53b) may be referred to as a second absorbent compound. If the second ion conductor layer (53b) includes an absorbent compound, the time required to achieve the ion conductivity performance of the polymer electrolyte membrane (time to reach complete wetting) may be prolonged, which may cause a problem in that the moisture contained in the electrolyte membrane cannot be evenly distributed.

[0093] The first ion conductor layer according to the present invention may include 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 absorbent 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), 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, more preferably 0.5 to 0.6 parts by weight. When the content of the above absorbent compound satisfies the above numerical range, the moisture content in the polymer electrolyte membrane is sufficient under high temperature and / or low humidity conditions, so that the hydrogen ion conductivity performance can be further improved, and at the same time, the time to reach complete wetting can be shortened.

[0095] In some embodiments of the present invention, after drying in a 90°C vacuum oven for 24 hours, the time to reach complete wetting of the polymer electrolyte membrane, which is measured at 1-minute intervals for 80 minutes while flowing 500ccm of nitrogen for 30 minutes and flowing nitrogen with 50% humidity 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 may be in a range where any one of the plurality of values ​​is 50 minutes or more as the upper limit. Here, the time to reach complete wetting is the time at which the ionic conductivity of the polymer electrolyte membrane is saturated. When the time to reach complete wetting satisfies the numerical range, the moisture absorption capacity of the polymer electrolyte membrane can be further improved.

[0096] In some embodiments of the present invention, the moisture 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, may be in a range where any one of the above multiple numerical values ​​is a lower limit and 8% or less is an upper limit. When the moisture content of the polymer electrolyte membrane satisfies the above numerical range, the moisture absorption capacity of the polymer electrolyte membrane can be further improved.

[0097] 3. Membrane-electrode assembly

[0098] FIG. 1b is a cross-sectional view showing a membrane-electrode assembly according to one embodiment of the present invention.

[0099] Referring to FIGS. 1A and 1B, 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 disposing 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 ion conductivity performance, and moisture generated at the cathode during fuel cell operation can be absorbed, thereby evenly distributing moisture within the polymer electrolyte membrane.

[0100] In some examples, the thickness of the first and second ion conductor layers (53a, 53b) may each independently be 0.5 to 40 μm, specifically 1 to 30 μm, and more specifically 1 to 20 μm. When the thickness of the first and second ion conductor layers satisfies the above numerical range, moisture generated at the cathode during fuel cell operation can be absorbed, thereby sufficiently evenly distributing moisture within the polymer electrolyte membrane.

[0101] When both the anode (20) and the cathode (20') are referred to as electrodes, the electrode (20, 20') includes an electrode substrate (40, 40') and a catalyst layer (30, 30') formed on the surface of the electrode substrate (40, 40'), and may further include a microporous layer (not shown) including conductive fine particles such as carbon powder or carbon black between the electrode substrate (40, 40') and the catalyst layer (30, 30') to facilitate material diffusion in the electrode substrate (40, 40').

[0102] In the above membrane-electrode assembly (100), an electrode (20) that is arranged on one side of the polymer electrolyte membrane (50) and causes an oxidation reaction to generate hydrogen ions and electrons from the fuel transferred to the catalyst layer (30) through the electrode substrate (40) is called an anode electrode.

[0103] An electrode (20') that is arranged on the other side of the polymer electrolyte membrane (50) and causes a reduction reaction to produce water from hydrogen ions supplied through the polymer electrolyte membrane (50) and an oxidizing agent that passes through the electrode substrate (40') to the catalyst layer (30') is called a cathode electrode.

[0104] The catalyst layers (30, 30') of the anode and cathode electrodes (20, 20') above include a catalyst. Any catalyst that participates in the cell reaction and can be used as a catalyst for a typical fuel cell may be used. Preferably, a platinum-based metal may 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), a platinum-M alloy, a non-platinum alloy, and combinations thereof, and more preferably, a combination of two or more metals selected from the platinum-based catalyst metal group may be used, but is not limited thereto, and any platinum-based catalyst metal usable in the present technical field may be used without limitation.

[0106] The above M may correspond to at least one 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 may be used alone or in combination of two or more 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.

[0107] In addition, the non-platinum alloy may be used alone or in combination of two or more 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.

[0108] The above catalyst may be used as a catalyst itself (black) or may be used by supporting it 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] Another embodiment of the present invention provides a fuel cell comprising the membrane-electrode assembly.

[0112] Referring to FIG. 2, a fuel cell (200) according to the present invention may include a fuel supply unit (210) that supplies a mixed fuel in which fuel and water are mixed, a reforming unit (220) that reforms the mixed fuel to generate a reformed gas containing hydrogen gas, a stack (230) that generates electrical energy by causing an electrochemical reaction between the reformed gas containing hydrogen gas supplied from the reforming unit (220) and an oxidizer, and an oxidizer supply unit (240) that supplies an oxidizer to the reforming unit (220) and the stack (230).

[0113] The above stack (230) may be equipped with a plurality of unit cells that generate electrical energy by inducing an oxidation / reduction reaction of a reforming gas containing hydrogen gas supplied from the reforming unit (220) and an oxidizing agent supplied from the oxidizing agent supply unit (240).

[0114] Each unit cell refers to a unit cell that generates electricity, and may include the membrane-electrode assembly that oxidizes / reduces oxygen in a reforming gas containing hydrogen gas and an oxidizing agent, and a separator (also called a bipolar plate, hereinafter referred to as a "separator") for supplying the reforming gas containing hydrogen gas and the oxidizing agent to the membrane-electrode assembly. The separator is positioned on both sides of the membrane-electrode assembly with the membrane-electrode assembly at the center. At this time, the separator plates each positioned at the outermost side of the stack are specifically referred to as end plates.

[0115] Among the above separators, the end plate may be provided with a first supply pipe (231) in the shape of a pipe for injecting reformed gas containing hydrogen gas supplied from the reforming unit (220), and a second supply pipe (232) in the shape of a pipe for injecting oxygen gas, and the other end plate may be provided with a first discharge pipe (233) for discharging reformed gas containing hydrogen gas that is ultimately unreacted and remains in a plurality of unit cells to the outside, and a second discharge pipe (234) for discharging oxidant that is ultimately unreacted and remains in the unit cells to the outside.

[0116] In the above fuel cell, the separator, fuel supply unit, and oxidizer supply unit constituting the electricity generation unit are used in a typical fuel cell, and therefore, a detailed description thereof is omitted in this specification.

[0117] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, this is merely an example, and the scope of the present invention is not limited by the following contents.

[0118] [Manufacturing Example 1: Manufacturing of an ionic conductor composition]

[0119] An ion conductor composition was prepared according to the composition shown in Table 1 below. In Table 1 below, the content of the absorbent compound was set as a relative content with respect to 100 parts by weight of the total solid content of the ion conductor dispersion (ion conductor).

[0120] Unit: Weight of ionic conductor 1)EDTAPhytic acidDeferasiroxPorphinePhthalocyanine12-crown-4Comparative Preparation Example 1100------Example Preparation Example 11000.5-----Example Preparation Example 2100-0.5----Example Preparation Example 3100--0.5---Example Preparation Example 4100---0.5--Example Preparation Example 5100----0.5-Example Preparation Example 6100-----0.51) Total solids content of 20 wt% Nafion dispersion (D2020 from Chemours, USA)

[0121] [Manufacturing Example 2: Manufacturing of a polymer electrolyte membrane (reinforced composite membrane)] <Comparative Example 1: Commercial reinforced composite membrane not containing an absorbent compound>

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

[0123] <Comparative Example 2: Reinforced composite membrane containing absorbent compound on both surfaces and inside of the reinforced composite membrane>

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

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

[0126] <Examples 1 to 6: Reinforced composite membrane having an ion conductor layer containing an absorbent compound disposed on only one side of the reinforced composite membrane>

[0127] A reinforced composite membrane was manufactured using the same method as Comparative Example 1, but the impregnation time was changed from 1 hour to 30 minutes to form a preliminary reinforced composite membrane in which a second ion conductor layer not including an absorbent compound was disposed on only one side of the reinforced composite membrane.

[0128] On the other side opposite to the one side of the above preliminary reinforced composite membrane, a dried ion conductor layer (each thickness: 3 μm) using the ion conductor composition (containing an absorbent compound) according to the above Preparation Examples 1 to 6 is laminated using a laminating method (pressure 0.4 kgf / cm 2 ; After applying at a temperature of 80°C and a time of 10 minutes, the first ion conductor layer (thickness: 3 μm) was formed by drying at 120°C for 30 minutes.

[0129] Unit: Weight of ionic conductor 1) EDTAPhytic acidDeferasiroxPorphinePhthalocyanine12-crown-4RemarksComparative Example 1100------Porous support 2) Comparative Example 21000.5-----Porous Support 2 +Anode+CathodeExample 11000.5-----Porous support 2) +Anode Example 2100-0.5----Porous support 2) +Anode Example 3100--0.5---Porous support 2) +Anode Example 4100---0.5--Porous support 2) +Anode Example 5100----0.5-Porous support 2) +Anode Example 6100-----0.5 Porous support 2)+Anode 1) Total solids of 20 wt% Nafion dispersion (D2020 from Chemours, USA) 2) PTFE (Polytetrafluoroethylene) support (80% porosity; pore size of 0.45 μm; thickness of 10 μm)

[0130] [Experimental Example: Ionic Conductivity, Low Moisture Content, and Dimensional Stability Evaluation Experiment]

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

[0132] ionic conductivity

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

[0134] [Equation 2]

[0135] σ=L / RS

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

[0137] Time to reach full wetness

[0138] At this time, in order to limit the location where humidity is supplied, one side of the film (polymer electrolyte membrane) was adjusted to a state where the film was completely attached. In this case, it was dried for 24 hours in a vacuum oven at 90℃. After placing the dried electrolyte membrane in the ion conductivity cell, 500ccm of nitrogen was flowed for 30 minutes in a completely dry state. Afterwards, nitrogen with 50% humidity was flowed at the same flow rate, and the ion conductivity was measured every minute for 80 minutes to measure the time until the ion conductivity was saturated, thereby measuring the time until the polymer electrolyte membrane reached wet equilibrium. At this time, if the time until complete wetness is reached is less than 65 minutes, the moisture absorption capacity of the polymer electrolyte membrane can be evaluated as improved compared to before.

[0139] 2) Low humidity function rate (high temperature / low humidity conditions; 80℃ / 50% RH)

[0140] The polymer electrolyte membrane of the above manufacturing example 1 was washed several times with deionized water, and the washed polymer electrolyte membrane was dried in a reduced pressure dryer at 90°C for 24 hours, and then the weight was measured (W dry ) Then, the same film was left in a chamber under conditions of 80°C and 50% RH for 4 hours, and its weight was measured in the chamber (W wet ) Then, the moisture content was calculated by the following mathematical formula 3. When the moisture content range is 4.8% or more under high temperature and low humidity conditions, it may mean that the performance of the membrane-electrode assembly is excellent.

[0141] [Equation 3]

[0142] Water uptake (%) = [(W wet -W dry ) / (W dry )] X 100

[0143] Sample Basket Structure Compound Application Location Absorbent Compound Type Ionic Conductivity (S / cm) Time to Complete Wetness (min) Low Moisture Content (%) Comparative Example 1--0.0213733.123 Comparative Example 2 First and Second Ion Conductor Layers EDTA 0.0274656.028 Example 1 First Ion Conductor Layer EDTA 0.0265615.761 Example 2 First Ion Conductor Layer Phytic Acid 0.0237525.476 Example 3 First Ion Conductor Layer Deferasirox 0.0255645.502 Example 4 First Ion Conductor Layer Porphine 0.0273577.300 Example 5 First Ion Conductor Layer Phthalocyanine 0.0269585.856 Example 6 First Ionic conductor layer 12-crown-40.0257585.731

[0144] In Table 3 above, when Comparative Example 1 and Example 1 are compared in terms of ionic conductivity of the polymer electrolyte membrane depending on the presence or absence of the absorbent compound, compared to the polymer electrolyte membrane (Comparative Example 1) that does not include the absorbent compound, the polymer electrolyte membrane (Example 1) in which the absorbent compound is applied only to the first ion conductor layer has high absorbency, thereby increasing the low moisture content and ionic conductivity, and shortening the time to reach complete wetting, thereby exhibiting the effect of uniformly controlling the moisture distribution of the polymer electrolyte membrane. When Comparative Example 2 and Example 1 are compared in terms of the time to reach complete wetting depending on the application location of the absorbent compound, Comparative Example 2 in which the absorbent compound is applied to both the first and second ion conductor layers exhibited slightly higher ionic conductivity than Example 1 in which the absorbent compound is applied only to the first ion conductor layer, but showed a problem in that the time to reach complete wetting was relatively long, making it difficult to uniformly control the moisture distribution within the electrolyte membrane. On the other hand, Example 1 showed the effect of uniformly controlling moisture distribution by applying an absorbent compound only to the first ion conductor layer, thereby increasing the ion conductivity to an appropriate level and shortening the time required to reach complete wetting.

[0145] Although the 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 made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. Porous support; A first ion conductor layer disposed on the 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; The above first ion conductor layer is, Containing ionic conductors and absorbent compounds, The above absorbent compound forms a basket structure through molecular motion, The above second ion conductor layer is, Does not contain absorbent compounds, Polymer electrolyte membrane.

2. In paragraph 1, The absorbent compound of the first ion conductor layer is, A hexadentate ligand; an aliphatic ring compound having 5 to 6 carbon atoms containing 4 or more hydrophilic functional groups in a side chain; a 4-pyrrole containing compound; a triazole compound containing 3 or more hydrophilic functional groups in a side chain; a phosphonic acid compound; a compound containing 2 or more benzene rings in a molecule; a chain-like compound containing an amine group and a carboxyl group; and a crown ether compound; comprising at least one of the following: Polymer electrolyte membrane.

3. In paragraph 2, The above hexadentate ligand is, Any one selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), and combinations thereof. Polymer electrolyte membrane.

4. In paragraph 2, An aliphatic ring compound having 5 to 6 carbon atoms and containing 4 or more hydrophilic functional groups in the side chain, Contains phytic acid Polymer electrolyte membrane.

5. In paragraph 2, The above 4-pyrrole containing compound is, Comprising any one selected from the group consisting of substituted or unsubstituted porphine; substituted or unsubstituted phthalocyanine; and combinations thereof; Polymer electrolyte membrane.

6. In paragraph 2, A triazole compound containing three or more hydrophilic functional groups in the side chain is Containing deferasirox, Polymer electrolyte membrane.

7. In paragraph 2, The above crown ether compound is, A molecular structure comprising a parent molecule represented by the general formula 1, Polymer electrolyte membrane: [General Formula 1] [C2H4O] n In the above general formula 1, n is 3 to 10.

8. In paragraph 1, The above ion conductor is included in the internal pores of the porous support, Polymer electrolyte membrane.

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

10. A fuel cell comprising a membrane-electrode assembly according to paragraph 9.

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