Catalyst layer for fuel cell, membrane-electrode assembly, and fuel cell comprising same

Abstract

Disclosed is a catalyst layer for a fuel cell having improved water repellency, thermal conductivity, and output. The catalyst layer according to one aspect comprises a catalyst and a functional surface layer disposed on at least one surface thereof, the functional surface layer comprising functional nanoparticles comprising any one or more selected from the group consisting of a first fluorinated carbon nanoparticles, boron nitride nanoparticles, fluorinated boron nitride nanoparticles, and a composite containing second fluorinated carbon nanoparticles and IrOx nanoparticles (x is 1, 2, or 3).

Description

Catalyst layer for fuel cell, membrane-electrode assembly and fuel cell including same

[0001] The present disclosure relates to a catalyst layer for a fuel cell, and more specifically, to a catalyst layer for a fuel cell, a membrane-electrode assembly, and a fuel cell including the same.

[0002] Fuel cells directly convert the chemical energy generated by fuel oxidation into electrical energy. Their high energy efficiency and environmentally friendly characteristics, coupled with minimal pollutant emissions, have drawn attention as a next-generation energy source. These fuel cells typically consist of a polymer electrolyte membrane, with an anode and cathode formed on either side. This structure is called a membrane electrode assembly (MEA).

[0003] Fuel cells can be classified into alkaline electrolyte fuel cells and polymer electrolyte membrane fuel cells (PEMFC) depending on the type of electrolyte membrane. Among them, polymer electrolyte membrane fuel cells are attracting attention as portable, automotive, and home power sources due to their advantages such as low operating temperature of less than 100℃, fast start-up and response characteristics, and excellent durability. A representative example of such polymer electrolyte membrane fuel cells is the proton exchange membrane fuel cell (PEMFC), which uses hydrogen gas as fuel.

[0004] Meanwhile, polymer electrolyte membrane fuel cells still face technical challenges, such as water overflow within the fuel cell, abnormal gas supply, and heat generation during operation, making it difficult to improve the stability and durability of the membrane-electrode assembly. In particular, when a reverse voltage phenomenon at the anode occurs due to hydrogen gas depletion, the high voltage causes corrosion of the carbon-based support, significantly reducing the stability and durability of the membrane-electrode assembly.

[0005] According to one aspect of the present invention, a catalyst layer for a fuel cell is provided that improves output performance and durability.

[0006] According to another aspect of the present invention, a catalyst layer for a fuel cell having excellent water-repellent performance is provided by preventing flooding of the pores of an electrode with water.

[0007] According to another aspect of the present invention, a catalyst layer for a fuel cell is provided having excellent heat dissipation performance by increasing thermal conductivity.

[0008] According to another aspect of the present invention, a catalyst layer for a fuel cell having reverse voltage durability is provided.

[0009] According to another aspect of the present invention, a membrane-electrode assembly including the catalyst layer for a fuel cell is provided.

[0010] According to another aspect of the present invention, a fuel cell including the membrane-electrode assembly is provided.

[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, there is provided a catalyst layer; and a functional surface layer disposed on at least one surface of the catalyst layer, wherein the functional surface layer comprises first fluorinated carbon nanoparticles; boron nitride nanoparticles; second fluorinated carbon nanoparticles and IrO. x A catalyst layer for a fuel cell is provided, comprising at least one functional nanoparticle selected from the group consisting of a composite comprising nanoparticles (x is 1, 2 or 3); and boron nitride fluoride nanoparticles.

[0013] According to the second aspect of the present invention, in the first aspect, the content of fluorine may be 5 wt% or more and 90 wt% or less based on the total weight of the first fluorinated carbon nanoparticle.

[0014] According to a third aspect of the present invention, in the first or second aspect, the content of fluorine may be 5 wt% or more and 90 wt% or less based on the total weight of the fluorinated boron nitride nanoparticles.

[0015] According to a fourth aspect of the present invention, in any one of the first to third aspects, the thickness of the functional surface layer may be 0.2 µm or more and 2.0 µm or less.

[0016] According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the functional surface layer may cover 20% or more and 80% or less of the total active area of ​​one side in contact with the catalyst layer.

[0017] According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the IrO x Nanoparticles (x is 1, 2 or 3) are supported on the second fluorocarbon nanoparticles, and based on the total weight of the complex, the IrO x The loading amount of nanoparticles may be 30 wt% or more and 75 wt% or less.

[0018] According to the seventh aspect of the present invention, in any one of the first to sixth aspects, the loading amount of the functional nanoparticles is 0.03 mg / cm 2 More than 1.0 mg / cm 2 It could be as follows:

[0019] According to an eighth aspect of the present invention, a membrane-electrode assembly is provided, comprising: a polymer electrolyte membrane; and a catalyst layer for a fuel cell according to any one of the first to seventh aspects disposed on at least one surface of the polymer electrolyte membrane.

[0020] According to a ninth aspect of the present invention, the catalyst layer for the fuel cell includes a first catalyst layer disposed on one surface of the polymer electrolyte membrane, the functional surface layer includes a first functional surface layer disposed on one surface of the first catalyst layer, the first functional surface layer includes the composite, and the first catalyst layer may be an anode.

[0021] According to a tenth aspect of the present invention, a fuel cell is provided comprising a membrane-electrode assembly according to the eighth or ninth aspect.

[0022] According to one aspect of the present invention, a catalyst layer for a fuel cell having excellent durability even when the fuel cell is operated for a long period of time can be provided, water repellency within the fuel cell can be increased to effectively prevent flooding in which water fills the pores of the electrode, and thermal conductivity can be increased to effectively release heat generated during fuel cell operation.

[0023] According to another aspect of the present invention, when a reverse voltage phenomenon occurs in which the anode potential increases due to a lack of hydrogen gas and the cathode potential is maintained at its initial state while the cell voltage changes to a negative value, the formation of a local hydrogen / oxygen interface on the anode side can be effectively prevented, thereby improving reverse voltage durability.

[0024] 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.

[0025] FIG. 1 is a cross-sectional view of a catalyst layer for a fuel cell according to one embodiment of the present invention.

[0026] FIG. 2 is a cross-sectional view of a membrane-electrode assembly according to one embodiment of the present invention.

[0027] FIG. 3 is a cross-sectional view of a membrane-electrode assembly according to another embodiment of the present invention.

[0028] Figure 4 is a schematic diagram illustrating a fuel cell according to one embodiment of the present invention.

[0029] FIG. 5a is a scanning electron microscope (SEM) photograph of the surface of a membrane-electrode assembly manufactured according to Example 1, and FIG. 5b is a schematic diagram of FIG. 5a.

[0030] Fig. 6a is a scanning electron microscope (SEM) photograph of the surface of a membrane-electrode assembly manufactured according to Example 2, and Fig. 6b is a schematic diagram of Fig. 6a.

[0031] Fig. 7a is a scanning electron microscope (SEM) photograph of the surface of a membrane-electrode assembly manufactured according to Example 3, and Fig. 7b is a schematic diagram of Fig. 7a.

[0032] Fig. 8a is a surface scanning electron microscope (SEM) photograph of a membrane-electrode assembly manufactured according to Example 4, and Fig. 8b is a schematic diagram of Fig. 8a.

[0033] Figure 9 shows the results of performance evaluations after initial and durability evaluations of membrane-electrode assemblies manufactured according to comparative examples and examples.

[0034] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0035] The terms "comprise" and / or "comprising" in this specification specify the presence of stated features, steps, numbers, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, numbers, operations, elements, elements and / or groups thereof.

[0036] 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.

[0037] The term "connection" as used herein refers not only to the direct connection of certain elements, but also includes an indirect connection where another element is interposed between the elements.

[0038] If multiple embodiments are described in this specification, the embodiments may be combined unless specifically stated otherwise. In this case, the effects of the present invention may be defined as including the effects resulting from each embodiment and the effects resulting from the organic combination of the embodiments. For example, even if Embodiments 1 and 2 are described independently in this specification, Embodiments 1 and 2 may be organically combined with each other unless the context clearly indicates otherwise, and the effects of the present invention may include the effects resulting from the combination of Embodiments 1 and 2.

[0039] The numerical range indicated by the term "to" in this specification refers to a numerical range that includes the values ​​stated before and after the term as the lower and upper limits, respectively. For example, if "a" and "b" are stated in the specification, it can be understood that "a" and "b" are stated.

[0040] In the present specification, when multiple numerical values ​​are disclosed as the upper and lower limits of any numerical range, the numerical range disclosed in the present 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 value and the upper limit value, respectively. For example, when a or more, or b or more; and c or less or d or less are described, it can be understood that a or more and c or less, a or more and d or less, b or more and c or less, or b or more and d or less are described.

[0041] As used herein, terms such as "about" or "substantially" mean a reasonable amount of variation from the term that does not significantly alter the final result. These terms may be interpreted to include a variation of at least ±5% or at least ±10%, provided that such variation does not alter the meaning of the term and render it invalid.

[0042] 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 element is formed as a layer or film directly on top of one element, the coverage of the other element on the surface of the one element 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."

[0043] In this specification, the average particle size is the particle diameter (D) when the cumulative percentage in the volume-based particle size distribution curve is 50% when measured by a laser diffraction particle size distribution measuring device. 50 ) can be defined. For example, the average size of the particles can be calculated by dispersing the target particles in a dispersion medium, introducing them into a commercially available laser diffraction particle size measuring device (e.g., Microtrac S3500), and measuring the difference in diffraction pattern according to particle size when the particles pass through a laser beam.

[0044] According to one aspect of the present invention, there is provided a catalyst layer comprising a functional surface layer disposed on at least one surface of the catalyst layer, wherein the functional surface layer comprises first fluorinated carbon nanoparticles; boron nitride nanoparticles; second fluorinated carbon nanoparticles and IrO. x A catalyst layer for a fuel cell is provided, comprising at least one functional nanoparticle selected from the group consisting of a composite comprising nanoparticles (x is 1, 2 or 3); and boron nitride fluoride nanoparticles. According to one aspect of the present invention, through the functional surface layer comprising the composition, a catalyst layer for a fuel cell having excellent durability even when the fuel cell is operated for a long period of time can be provided, and water repellency within the fuel cell can be increased to effectively prevent flooding in which water fills the pores of the electrode, and thermal conductivity can be increased to effectively release heat generated during fuel cell operation. In addition, according to another aspect of the present invention, when a reverse voltage phenomenon occurs in which the anode potential increases due to a lack of hydrogen gas and the cathode potential is maintained at an initial state and the cell voltage changes to a negative value, local corrosion of carbon by water on the anode side can be effectively prevented by the action of a water-splitting catalyst, thereby improving reverse voltage durability.

[0045] Hereinafter, the configuration of the present invention will be described in more detail with reference to the drawings.

[0046] 1. Catalyst layer for fuel cells

[0047] FIG. 1 is a cross-sectional view of a catalyst layer for a fuel cell according to one embodiment of the present invention.

[0048] Referring to FIG. 1, a catalyst layer (CL) for a fuel cell according to the present invention includes a catalyst layer (20) and a functional surface layer (30) disposed on at least one surface of the catalyst layer (20). For example, the functional surface layer (30) may be disposed on one or both surfaces of the catalyst layer (20).

[0049] The functional surface layer (30) according to the present invention comprises first fluorinated carbon nanoparticles; boron nitride nanoparticles; second fluorinated carbon nanoparticles and IrO x A composite comprising nanoparticles (x is 1, 2 or 3); and at least one functional nanoparticle selected from the group consisting of boron nitride nanoparticles. In the present specification, “carbon nanoparticle” may be defined as a nanoparticle containing carbon. For example, the average size or average length in the major axis direction of the carbon nanoparticles may be 0.1 to 1000 nm. In addition, the carbon nanoparticles are not particularly limited, but may specifically include at least one selected from the group consisting of graphite, Super P, carbon fiber, carbon sheet, carbon black, Ketjen black, Denka black, acetylene black, carbon nanotube (CNT), carbon sphere, carbon ribbon, fullerene, activated carbon, carbon nanoball, carbon nanohorn, carbon nanocage, carbon nanoring, carbon aerogel, and graphene.

[0050] The first fluorinated carbon nanoparticle according to the present invention may refer to a carbon nanoparticle having a fluorinated surface, as described above. Specifically, the first fluorinated carbon nanoparticle may have an excellent water-repellent property because it contains fluorine atoms that readily form stable chemical bonds with other elements.

[0051] For example, the first fluorinated carbon nanoparticle is (C2F) n , (CF) n and n may be an integer greater than or equal to 1. In addition, the average size of the first fluorinated carbon nanoparticles may be 50 to 400 nm, and specifically 60 to 300 nm. The first fluorinated carbon nanoparticles may be produced, for example, by a reaction between fluorine gas (F2) and carbon nanoparticles.

[0052] In some embodiments of the present invention, the fluorine content may be 5 wt% or more and 90 wt% or less based on the total weight of the first fluorocarbon nanoparticles. Specifically, the fluorine content may be 5 wt% or more, 10 wt% or more, 15 wt% or more, 20 wt% or more, 25 wt% or more, or 28 wt% or more based on the total weight of the first fluorocarbon nanoparticles; and 30 wt% or less, 35 wt% or less, 40 wt% or less, 45 wt% or less, 50 wt% or less, 55 wt% or less, 60 wt% or less, 65 wt% or less, 70 wt% or less, 75 wt% or less, 80 wt% or less, 85 wt% or less, or 90 wt% or less. The content of the fluorine can be varied by controlling the content of the fluorine gas and the content of the carbon nanoparticles, and by controlling it within the above numerical range, a membrane-electrode assembly with excellent battery output performance, water-repellent performance, and durability can be realized. Specifically, since water-repellent performance (durability) and output performance are in a trade-off relationship in which one performance increases while the other decreases, the two performances in the trade-off relationship can be achieved simultaneously by controlling the content of the fluorine. For example, the content of the fluorine can be analyzed through EDS (Energy-dispersive X-ray spectroscopy) elemental analysis using a scanning electron microscope (SEM).

[0053] Meanwhile, in the present specification, “loading amount” may refer to the weight of functional nanoparticles per unit area of ​​the functional surface layer. For example, the loading amount of the functional nanoparticles may be calculated by measuring the weight of a measurement sample composed of the catalyst layer and the functional surface layer, and the weight of a reference sample composed of the catalyst layer, respectively. For example, the loading amount of the functional nanoparticles may be changed by adjusting the content of each functional nanoparticle in the composition for forming a functional surface layer, which will be described later.

[0054] In some embodiments of the present invention, the loading amount of the first fluorinated carbon nanoparticles included in the functional surface layer (30) is 0.03 mg / cm 2 More than 1.0 mg / cm 2 It may be less than or equal to 0.05 mg / cm. Specifically, the loading amount of the first fluorinated carbon nanoparticle is 0.05 mg / cm. 2 Above, 0.10 mg / cm 2 Above, 0.15 mg / cm 2 Above, 0.20 mg / cm 2 Above, 0.25 mg / cm 2 Above, 0.30 mg / cm 2 Above, 0.35 mg / cm 2 Above, 0.40 mg / cm 2 Above, 0.50 mg / cm 2 or 0.51 mg / cm 2 above; and 0.70 mg / cm 2 Below 0.75 mg / cm 2 Below 0.80 mg / cm 2 Below 0.85 mg / cm 2 Below 0.90 mg / cm 2 Below 0.95 mg / cm 2 Less than or equal to 0.98 mg / cm 2 It may be as follows. In some embodiments of the present invention, by controlling the loading amount of the first fluorinated carbon nanoparticles within the above numerical range, electrical conductivity, water repellency, and durability of the catalyst layer for a fuel cell can be achieved simultaneously.

[0055] Boron nitride (BN) nanoparticles according to the present invention may have characteristics such as high thermal conductivity and heat resistance. The boron nitride nanoparticles may be, for example, amorphous boron nitride, cubic boron nitride (cBN), or hexagonal boron nitride (hBN). The average size of the boron nitride nanoparticles may be 50 to 400 nm, and specifically, 100 to 300 nm.

[0056] In some embodiments of the present invention, the loading amount of the boron nitride nanoparticles included in the functional surface layer (30) is 0.03 mg / cm 2 More than 1.0 mg / cm 2 It may be less than or equal to 0.05 mg / cm. Specifically, the loading amount of the boron nitride nanoparticles is 0.05 mg / cm. 2 Above, 0.10 mg / cm 2 Above, 0.15 mg / cm 2 Above, 0.20 mg / cm 2 Above, 0.25 mg / cm 2 Above, 0.30 mg / cm 2 Above, 0.35 mg / cm 2 Above, 0.40 mg / cm 2 Above, 0.50 mg / cm 2 or 0.51 mg / cm 2 above; and 0.70 mg / cm 2 Below 0.75 mg / cm 2 Below 0.80 mg / cm 2 Below 0.85 mg / cm 2 Below 0.90 mg / cm 2 Below 0.95 mg / cm 2 Less than or equal to 0.98 mg / cm 2It may be as follows. In some embodiments of the present invention, by controlling the loading amount of the boron nitride nanoparticles within the above numerical range, the electrical conductivity performance of the catalyst layer for a fuel cell and the performance of effectively dissipating heat generated during fuel cell operation can be achieved simultaneously.

[0057] As used herein, "composite" may be defined as a material in which two or more substances are combined to form physically or chemically distinct phases while exhibiting more effective functions. Here, the combination of two or more substances may refer to physical and / or chemical bonds. For example, the term "composite" may be defined as a distinct term from a mixture of two or more substances that are not combined.

[0058] The functional surface layer (30) according to the present invention comprises second fluorinated carbon nanoparticles and IrO x A composite may include nanoparticles (x is 1, 2 or 3), specifically second fluorocarbon nanoparticles and IrO x It may include a complex composed of nanoparticles (x is 1, 2 or 3). More specifically, the IrO x The nanoparticles can be supported on the second fluorocarbon nanoparticles.

[0059] For example, IrO supported on the second fluorinated carbon nanoparticle x The average size of the nanoparticles may be 1 to 60 nm, specifically 3 to 50 nm. The second fluorocarbon nanoparticles may be the same as or different from the first fluorocarbon nanoparticles. IrO x The nanoparticles can improve the reverse voltage durability of the membrane-electrode assembly by being supported on the second fluorinated carbon nanoparticles that serve as a support, and can effectively prevent flooding of the electrode pores due to the inherent water-repellent properties of fluorine atoms.

[0060] According to some embodiments of the present invention, IrO supported on the second fluorinated carbon nanoparticles x In nanoparticles, x can be 2. IrO2 can further improve reverse voltage durability by effectively preventing the formation of local hydrogen / oxygen interfaces on the anode side compared to IrO and IrO3.

[0061] According to some embodiments of the present invention, based on the total weight of the complex, the IrO x The loading amount of nanoparticles may be 30 wt% or more and 75 wt% or less. Specifically, the IrO x The loading amount of the nanoparticles may be 35 wt% or more, 40 wt% or more, 42 wt% or more, 44 wt% or more, 46 wt% or more, 48 wt% or more, 49 wt% or more, or 50 wt% or more; and 51 wt% or less, 52 wt% or less, 54 wt% or less, 56 wt% or less, 58 wt% or less, 60 wt% or less, 65 wt% or less, or 70 wt% or less. Here, IrO x The loading amount of nanoparticles is 2-fluorocarbon nanoparticles and IrO x It may be a content relative to the total weight of the composite composed of nanoparticles. According to some embodiments of the present invention, the IrO x By controlling the loading amount of nanoparticles within the above numerical range, not only can the reverse voltage durability of the membrane-electrode assembly be further improved, but also flooding, in which water fills the electrode pores, can be more effectively prevented due to the inherent water-repellent properties of fluorine atoms. For example, the IrO x The loading amount of nanoparticles can be analyzed by any one method selected from the group consisting of XRF (X-Ray Fluorescence Spectrometry), ICP (Inductively Coupled Plasma Spectrometry), gravimetric analysis, and combinations thereof.

[0062] In some embodiments of the present invention, the loading amount of the complex included in the functional surface layer (30) is 0.03 mg / cm 2 More than 1.0 mg / cm 2 It may be less than or equal to 0.05 mg / cm. Specifically, the loading amount of the complex is 0.05 mg / cm. 2 Above, 0.10 mg / cm 2 Above, 0.15 mg / cm 2 Above, 0.20 mg / cm 2 Above, 0.25 mg / cm 2 Above, 0.30 mg / cm 2 Above, 0.35 mg / cm 2 Above, 0.40 mg / cm 2 Above, 0.50 mg / cm 2 or 0.51 mg / cm 2 above; and 0.70 mg / cm 2 Below 0.75 mg / cm 2 Below 0.80 mg / cm 2 Below 0.85 mg / cm 2 Below 0.90 mg / cm 2 Below 0.95 mg / cm 2 Less than or equal to 0.98 mg / cm 2 It may be as follows. In some embodiments of the present invention, by controlling the loading amount of the complex within the above numerical range, not only can the reverse voltage durability of the membrane-electrode assembly be improved while maintaining the electrical conductivity at an appropriate level, but also flooding, in which water fills the electrode pores, can be effectively prevented due to the inherent water-repellent properties of fluorine atoms.

[0063] Fluoroboron nitride nanoparticles according to the present invention may refer to nanoparticles having a fluorinated surface. Specifically, the fluoroboron nitride nanoparticles may have excellent water-repellent properties because they contain fluorine atoms that readily form stable chemical bonds with other elements.

[0064] In some embodiments of the present invention, the loading amount of fluorinated boron nitride nanoparticles included in the functional surface layer (30) is 0.03 mg / cm 2 More than 1.0 mg / cm 2 It may be less than or equal to 0.05 mg / cm. Specifically, the loading amount of the above-mentioned fluorinated boron nitride nanoparticles is 0.05 mg / cm. 2 Above, 0.10 mg / cm 2 Above, 0.15 mg / cm 2 Above, 0.20 mg / cm 2 Above, 0.25 mg / cm 2 Above, 0.30 mg / cm 2 Above, 0.35 mg / cm 2 Above, 0.40 mg / cm 2 Above, 0.50 mg / cm 2 or 0.51 mg / cm 2 above; and 0.70 mg / cm 2 Below 0.75 mg / cm 2 Below 0.80 mg / cm 2 Below 0.85 mg / cm 2 Below 0.90 mg / cm 2 Below 0.95 mg / cm 2 Less than or equal to 0.98 mg / cm 2 It may be as follows. In some embodiments of the present invention, by controlling the loading amount of the fluorinated boron nitride nanoparticles within the above numerical range, electrical conductivity, water repellency, and durability of the catalyst layer for a fuel cell can be achieved simultaneously.

[0065] For example, the average size of the above-described fluorinated boron nitride nanoparticles may be 50 to 400 nm, and specifically 100 to 300 nm. For example, the above-described fluorinated boron nitride nanoparticles may be produced by a reaction between fluorine gas (F2) and boron nitride nanoparticles.

[0066] In some embodiments of the present invention, the fluorine content may be 5 wt% or more and 90 wt% or less, based on the total weight of the fluoroboron nitride nanoparticles. Specifically, the fluorine content may be 5 wt% or more, 10 wt% or more, 15 wt% or more, 20 wt% or more, 25 wt% or more, or 28 wt% or more, and 30 wt% or less, 35 wt% or less, 40 wt% or less, 45 wt% or less, 50 wt% or less, 55 wt% or less, 60 wt% or less, 65 wt% or less, 70 wt% or less, 75 wt% or less, 80 wt% or less, 85 wt% or less, or 90 wt% or less, based on the total weight of the fluoroboron nitride nanoparticles. The above fluorine content can be varied by adjusting the content of the fluorine gas and the content of the boron nitride nanoparticles, but when it satisfies the above numerical range, a membrane-electrode assembly with excellent battery output performance, water repellency, and durability can be realized. For example, the fluorine content can be analyzed through EDS (Energy-dispersive X-ray spectroscopy) elemental analysis using a scanning electron microscope (SEM).

[0067] The thickness of the functional surface layer (30) according to the present invention may be 0.2 µm or more and 2.0 µm or less. Specifically, the thickness of the functional surface layer (30) may be 0.3 µm or more, 0.5 µm or more, 0.7 µm or more, 0.9 µm or more, or 1.0 µm or more; and 1.5 µm or less, 1.8 µm or less, or 2.0 µm or less. When the thickness of the functional surface layer (30) satisfies the above numerical range, a catalyst layer for a fuel cell having better durability even when the fuel cell is operated for a long period of time can be provided, the water repellency within the fuel cell can be further increased to effectively prevent flooding in which water fills the pores of the electrode, and the thermal conductivity can be increased to more effectively release the heat generated during the operation of the fuel cell. For example, if the functional surface layer (30) forms a cluster structure of particles, so that the surface of the functional surface layer is not flat, the thickness of the functional surface layer may be the average value of the maximum thickness and the minimum thickness of the functional surface layer in a cross-sectional view taken vertically across the functional surface layer. For example, the thickness of the functional surface layer may be measured using a scanning electron microscope or a transmission electron microscope.

[0068] According to one embodiment of the present invention, the functional surface layer (30) may cover 20% or more and 80% or less of the total active area of ​​one side of the catalyst layer for the fuel cell. Specifically, the functional surface layer (30) may cover 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, or 60% or more of the total active area of ​​one side of the catalyst layer for the fuel cell; and 65% or less, 70% or less, 75% or less, or 80% or less. By adjusting the area occupied by the functional surface layer (30) within the above numerical range based on the total active area, the electrical conductivity may be implemented at an appropriate level, and at the same time, the effects that each functional nanoparticle intends to implement may be achieved. Here, the "total active area" refers to the area where an electrochemical reaction of the catalyst layer for a fuel cell occurs, and can be quantitatively measured, for example, by CV (cyclic voltammetry). For example, one surface of the catalyst layer for a fuel cell, which serves as the reference for the total active area, may be a surface facing the surface where the polymer electrolyte membrane (10) and the catalyst layer for a fuel cell (20) come into contact.

[0069] According to another embodiment of the present invention, the functional surface layer (30) can be formed by applying a composition for forming a functional surface layer to one or both sides of a commercial membrane-electrode assembly using a spray method or a slot-die coating method, followed by a drying step, and specifically, can be formed by applying the composition to one or both sides of the catalyst layer using a spray method or a slot-die coating method and a drying step. The reason for using the spray method or the slot-die coating method is that it minimizes deformation of the manufactured membrane-electrode assembly and allows for easy and rapid manufacturing. For example, when the functional nanoparticle is the composite, the catalyst layer can be an anode.

[0070] According to one embodiment of the present invention, the composition for forming a functional surface layer may include a dispersion medium and at least one functional nanoparticle selected from the group consisting of first fluorocarbon nanoparticles, boron nitride nanoparticles, and fluoroboron nitride nanoparticles. Based on the total weight of the composition for forming a functional surface layer, the content of at least one functional nanoparticle selected from the group consisting of first fluorocarbon nanoparticles, boron nitride nanoparticles, and fluoroboron nitride nanoparticles may be 2 to 25 wt%, specifically 3 to 20 wt%, and more specifically 4 to 15 wt%. When the content of at least one of the functional nanoparticles selected above satisfies the above numerical range, a catalyst layer for a fuel cell having superior durability even when the fuel cell is operated for a long period of time can be provided, water repellency within the fuel cell can be further increased to effectively prevent flooding in which water fills the pores of the electrode, and thermal conductivity can be increased to more effectively release heat generated during fuel cell operation.

[0071] The above dispersion medium can be used for the purpose of evenly dispersing functional nanoparticles. The solvent can be appropriately selected depending on the type of functional nanoparticles, but may include, for example, any one selected from the group consisting of water, alcohol, and mixtures thereof.

[0072] The catalyst layer (20) according to the present invention may be a commercial catalyst layer in the relevant technical field as a part of the catalyst layer (CL) for the fuel cell. Specifically, the catalyst layer (20) may include a platinum-based metal and / or a non-platinum-based metal that participates in the reaction of the cell.

[0073] For example, 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 relevant technical field may be used without limitation. The above M may correspond to at least one selected from the group consisting of, for example, 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, 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.

[0074] The above 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.

[0075] The catalyst used in the above catalyst layer may be used as a catalyst itself, or may be supported on a carrier. The carrier may be, for example, one selected from the group consisting of a carbon-based carrier, a porous inorganic oxide, a zeolite, and a combination thereof. The carbon-based carrier may be selected from, for example, graphite, Super P, carbon fiber, carbon sheet, carbon black, Ketjen black, Denka black, acetylene black, carbon nanotube (CNT), carbon sphere, carbon ribbon, fullerene, activated carbon, carbon nanofiber, carbon nanowire, carbon nanoball, carbon nanohorn, carbon nanocage, carbon nanoring, carbon aerogel, graphene, stabilized carbon, activated carbon, and a combination of at least one or more thereof, but is not limited thereto. The above porous inorganic oxide may correspond to at least one selected from the group consisting of, for example, zirconia, alumina, titania, silica, and ceria. The surface area of ​​the carrier may be 50 m 2 / g or more may be preferable, and the average particle diameter may be 10 to 300 nm. If the surface area of ​​the carrier is less than the above numerical range, a uniform distribution of metal nanoparticles may not be obtained.

[0076] 2. Membrane-electrode assembly

[0077] FIG. 2 is a cross-sectional view of a membrane-electrode assembly according to one embodiment of the present invention.

[0078] Referring to FIG. 2, a membrane-electrode assembly (100) according to one embodiment of the present invention may include a polymer electrolyte membrane (10) and a catalyst layer (CL) for a fuel cell disposed on at least one surface of the polymer electrolyte membrane (10).

[0079] The catalyst layer (20) according to the present invention may include a first catalyst layer (20a) and a second catalyst layer (20b). The first catalyst layer (20a) and the second catalyst layer (20b) may face each other with the polymer electrolyte membrane (10) interposed therebetween. Either the first catalyst layer (20a) or the second catalyst layer (20b) may be an anode and the other may be a cathode. According to one embodiment of the present invention, the functional surface layer (30) may be disposed on the surface of either one selected from the first catalyst layer and the second catalyst layer.

[0080] Figure 3 is a cross-sectional view of a membrane-electrode assembly according to another embodiment of the present invention. Parts that are repeated in the descriptions above are briefly described or omitted.

[0081] Referring to FIG. 3, the functional surface layer (30) according to the present invention may include a first functional surface layer (30a) and a second functional surface layer (30b). Specifically, the first functional surface layer (30a) may be disposed on one surface of the first catalyst layer (20a), and the second functional surface layer (30b) may be disposed on one surface of the second catalyst layer (20b).

[0082] Meanwhile, as an example, when a fuel cell unit cell is operated, the temperature of the oxygen gas supplied to the cathode can be controlled to be higher than the temperature of the hydrogen gas supplied to the anode. At this time, if the temperature of the oxygen gas is relatively increased, water generated in the fuel cell can be effectively removed. For example, the second functional surface layer (30b) can be in contact with the cathode, which is the second catalyst layer (20b), and the first functional surface layer (30a) can be in contact with the anode, which is the first catalyst layer (20a).

[0083] In some embodiments of the present invention, the thickness of the second functional surface layer (30b) may be greater than the thickness of the first functional surface layer (30a). In some embodiments of the present invention, the thickness of the second functional surface layer is adjusted to be greater than the thickness of the first functional surface layer, thereby allowing the reduction reaction of oxygen gas to proceed stably without structural deformation even at high fuel cell operating temperatures.

[0084] In some embodiments of the present invention, the loading amount of the first fluorocarbon nanoparticles included in the second functional surface layer (30b) may be higher than the loading amount of the first fluorocarbon nanoparticles included in the first functional surface layer (30a). According to some embodiments of the present invention, the loading amount of the first fluorocarbon nanoparticles included in the second functional surface layer (30b) is adjusted to be higher than the loading amount of the first fluorocarbon nanoparticles included in the first functional surface layer (30a), thereby achieving both water-repellent performance (durability) and output performance, which are in a trade-off relationship.

[0085] In some embodiments of the present invention, the loading amount of boron nitride nanoparticles included in the second functional surface layer (30b) may be higher than the loading amount of boron nitride nanoparticles included in the first functional surface layer (30a). According to some embodiments of the present invention, the loading amount of boron nitride nanoparticles included in the second functional surface layer (30b) is adjusted to be higher than the loading amount of boron nitride nanoparticles included in the first functional surface layer (30a), thereby achieving both the electrical conductivity performance of the catalyst layer for a fuel cell and the performance of effectively dissipating heat generated during fuel cell operation.

[0086] In some embodiments of the present invention, the loading amount of the fluorinated boron nitride nanoparticles included in the second functional surface layer (30b) may be higher than the loading amount of the fluorinated boron nitride nanoparticles included in the first functional surface layer (30a). According to some embodiments of the present invention, the loading amount of the fluorinated boron nitride nanoparticles included in the second functional surface layer (30b) is adjusted to be higher than the loading amount of the fluorinated boron nitride nanoparticles included in the first functional surface layer (30a), thereby achieving both water-repellent performance (durability) and output performance, which are in a trade-off relationship.

[0087] The first functional surface layer (30a) and the second functional surface layer (30b) according to the present invention may each independently include at least one functional nanoparticle selected from the group consisting of fluorinated carbon nanoparticles, boron nitride nanoparticles, and fluorinated boron nitride nanoparticles. Accordingly, the types of functional nanoparticles included in the first functional surface layer (30a) and the second functional surface layer (30b) may be the same or different from each other.

[0088] According to another embodiment of the present invention, the catalyst layer for the fuel cell may include a first catalyst layer disposed on one surface of the polymer electrolyte membrane, the functional surface layer may include a first functional surface layer disposed on one surface of the first catalyst layer, the first functional surface layer may include the composite, and a membrane-electrode assembly may be provided in which the first catalyst layer is an anode. When the composite is used, when a reverse voltage phenomenon occurs in which the anode potential increases due to a lack of hydrogen gas and the cathode potential is maintained in an initial state while the cell voltage changes to a negative value, corrosion of the carbon carrier by water on the anode side can be effectively prevented, thereby improving reverse voltage durability.

[0089] In some embodiments of the present invention, when hydrogen (100% RH) and air (100% RH) are supplied to the anode and the cathode in amounts that are stoichiometrically 1.5 / 2.0, respectively, under 80°C conditions using a fuel cell unit cell evaluation device, the current density at 0.6 V of the unit cell including the membrane-electrode assembly is 1000 mA / cm based on the output performance (End of Life, EOL) standard of 20,000 cycles performed using the DOE catalyst durability evaluation protocol. 2 Above, 1100 mA / cm 2 or 1200 mA / cm 2 It may be more than, specifically, any one of the multiple lower limits above and 2000 mA / cm 2 It could be as follows:

[0090] In some embodiments of the present invention, air of 50% RH is supplied to the cathode, nitrogen of 50% RH is supplied to the anode, and 0.2 A / cm 2 When a current of , the time (reverse potential time) required for a unit cell including a membrane-electrode assembly to reach -2.0 V may be 5 minutes or more, 10 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, 50 minutes or more, 60 minutes or more, 70 minutes or more, 100 minutes or more, 110 minutes or more, 120 minutes or more, 130 minutes or more, 140 minutes or more, 150 minutes or more, 170 minutes or more, 180 minutes or more, or 187 minutes or more, and specifically, may be any one of the plurality of lower limits and 200 minutes or less.

[0091] In some embodiments of the present invention, when a water droplet (10 μL / s) is dropped on the surface of the membrane-electrode assembly at room temperature using a contact angle measuring device, the contact angle of the dropped water droplet may be 100° or more, 110° or more, 120° or more, 125° or more, 126° or more, 133° or more, 139° or more, or 147° or more, and specifically, any one or more of the plurality of lower limits may be 150° or less. The polymer electrolyte membrane (10) according to the present invention may be in the form of a commercial single membrane or a reinforced composite membrane in the relevant technical field.

[0092] A polymer electrolyte membrane (10) according to one embodiment of the present invention may include an ionomer. Specifically, the ionomer may be any one selected from the group consisting of a fluorine-based ionomer, a hydrocarbon-based ionomer, and a mixture thereof.

[0093] The above fluorine-based ionomer may be, for example, any one selected from the group consisting of a fluorine-based polymer containing fluorine in the main chain, poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), a copolymer of tetrafluoroethylene and fluorovinyl ether containing a sulfonic acid group, a polystyrene-graft-ethylenetetrafluoroethylene copolymer, a polystyrene-graft-polytetrafluoroethylene copolymer, and mixtures thereof.

[0094] The hydrocarbon ionomers 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 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 nitrile, sulfonated polyarylene ether ether nitrile,It may be any one selected from the group consisting of sulfonated polyarylene ether sulfone ketone and mixtures thereof.

[0095] A polymer electrolyte membrane (10) according to another embodiment of the present invention may be a reinforced composite membrane in which an ion conductor is impregnated into a porous support. The ion conductor may be the same as or different from the ionomer described above.

[0096] The porous support according to the present invention may be a fluorinated support or a nanoweb support. Specifically, the fluorinated support may be, for example, 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.

[0097] The fluorinated support may include a perfluorinated polymer. The porous support may correspond to a more porous and stronger porous support obtained by extruding dispersion polymerized PTFE into a tape in the presence of a lubricant and stretching the material thus obtained. In addition, the amorphous content of the PTFE may be increased by heat treating the e-PTFE at a temperature exceeding the melting point of the PTFE (about 342°C). The e-PTFE film manufactured by the method may have micropores with various diameters and a porosity. The e-PTFE film manufactured by the method may have at least 35% pores, and the diameter of the micropores may be about 0.01 to 1 μm.

[0098] A nano web support according to one embodiment of the present invention may be a non-woven fibrous web composed of a plurality of randomly oriented fibers. The non-woven 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 non-woven 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. The fibers may include one or more polymer materials, and any material 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 include 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 polybutene, polylactic acid, polyvinyl alcohol, polyphenylene sulfide, polysulfones, fluid crystalline polymers, polyethylene-co-vinylacetate, polyacrylonitrile, cyclic polyolefins, polyoxymethylene, polyolefin-based thermoplastic elastomers, and combinations thereof, although the technical idea of ​​the present invention is not limited thereto.

[0099] A nanoweb support according to one embodiment of the present invention may be a support in which nanofibers are integrated in a nonwoven fabric form containing a large number of pores. The nanofibers preferably use hydrocarbon polymers that exhibit excellent chemical resistance and have hydrophobic properties, thereby preventing deformation due to moisture in high-humidity environments. Specifically, the hydrocarbon polymer 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, polyvinylidene fluoride, polyvinyl butylene, polyurethane, polybenzoxazole, polybenzimidazole, polyamideimide, polyethylene terephthalate, polyphenylene sulfide, polyethylene, polypropylene, copolymers thereof, and mixtures thereof, and among these, polyimide having superior heat resistance, chemical resistance, and dimensional stability may be preferably used.

[0100] The above nanoweb support is an aggregate of nanofibers in which nanofibers produced by electrospinning are randomly arranged. 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. 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.

[0101] The thickness of the nonwoven fibrous web may be 10 to 50 μm, specifically 15 to 43 μm. If the thickness of the nonwoven fibrous web is less than the above numerical range, the mechanical strength may be reduced, and if it exceeds the above numerical range, the resistance loss may increase, and the weight reduction and integration may be reduced. The nonwoven fibrous web may have 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.

[0102] The porosity of the porous support according to the present invention may be 30 to 90%, and preferably 60 to 85%. If the porosity of the porous support is less than the above numerical range, the impregnation property of the ion conductor may be reduced, and if it exceeds the above numerical range, the shape stability may be reduced, so that the post-process may not proceed smoothly. The porosity can be calculated by the ratio of the air volume in 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.

[0103] [Mathematical Formula 1]

[0104] Porosity (%) = (air volume in porous support / total volume of porous support) X 100

[0105] 3. Fuel cell

[0106] Another embodiment of the present invention can provide a fuel cell including the membrane-electrode assembly.

[0107] Figure 4 is a schematic diagram illustrating a fuel cell according to one embodiment of the present invention.

[0108] Referring to FIG. 4, 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 electric 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).

[0109] 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).

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] [Manufacturing Preparation Example 1: Preparation of Materials]

[0115] 1) Fluorinated carbon nanoparticles

[0116] Fluorinated carbon nanoparticles (D) having a fluorine content of 30% relative to the total weight of fluorinated carbon nanoparticles were prepared by plasma treatment on commercial carbon black (Vulcan XC-72). 50 =65 nm) was manufactured. The conditions for the plasma treatment are as follows: injecting a mixed gas consisting of 10 vol% fluorine-containing gas and 90 vol% diluted gas at atmospheric pressure, and reacting for 5 minutes at an output of 200 W.

[0117] 2) Boron nitride nanoparticles

[0118] Commercial B2O3 powder was treated with a high energy ball mill at 700 rpm under nitrogen gas for 100 minutes, and then ammonia gas was flowed at 150 ml / min, and heat-treated at 1200°C for 6 hours to obtain an average particle size (D 50 ) produced boron nitride nanoparticles with a size of 150 nm.

[0119] 3) Fluoroboronitride nanoparticles

[0120] The above boron nitride nanoparticles were treated with plasma to form fluorinated boron nitride nanoparticles (D 50 =160 nm) was manufactured. The conditions of the plasma treatment are as follows: a mixed gas consisting of 10 vol% fluorine-containing gas and 90 vol% diluted gas is injected at atmospheric pressure, and the reaction is performed for 5 minutes at an output of 200 W, and the fluorine content is 30 wt% relative to the total weight of the fluoroboron nitride nanoparticles.

[0121] 4) Complex (IrO x Fluorinated carbon nanoparticles loaded with nanoparticles)

[0122] 1 part by weight of the above fluorinated carbon nanoparticles was used as a carrier, mixed with 1 part by weight of Ir precursor (H2IrCl6) in an aqueous solution, and then 100 parts by weight of water and 10 parts by weight of ammonia water were additionally added and dispersed to prepare a dispersion. The dispersion was stirred for about 6 hours, and then the water was evaporated to obtain a powder. Through this, the average particle diameter (D 50 ) of fluorinated carbon nanoparticles with an average particle diameter (D) of 100 nm 50 ) was prepared as a composite containing IrO2 nanoparticles loaded with a size of 6 nm. At this time, the loading amount of IrO2 loaded on the composite was 50 wt% based on the total weight of the composite, and was measured through XRF (X-Ray Fluorescence Spectrometry) analysis.

[0123] [Manufacturing Preparation Example 2: Preparation of a Composition for Forming a Functional Surface Layer]

[0124] <Preparation Example 1: Composition containing fluorinated carbon nanoparticles>

[0125] A composition was prepared containing fluorinated carbon nanoparticles mixed with a 50% (v / v) ethanol aqueous solution at a weight ratio of 88:12.

[0126] <Preparation Example 2: Composition containing boron nitride nanoparticles>

[0127] A composition was prepared by mixing a 50% (v / v) ethanol aqueous solution and boron nitride nanoparticles at a weight ratio of 88:12.

[0128] <Preparation Example 3: Composition containing fluorinated boron nitride nanoparticles>

[0129] A composition was prepared by mixing a 50% (v / v) ethanol aqueous solution and fluorinated boron nitride nanoparticles in a weight ratio of 88:12.

[0130] <Preparation Example 4: Composition containing a complex>

[0131] 50% (v / v) ethanol aqueous solution and complex (IrO x A composition was prepared in which nanoparticles (x=2) loaded with fluorinated carbon nanoparticles) were mixed in a weight ratio of 94:6.

[0132] [Manufacturing Example 1: Manufacturing of a Membrane-Electrode Assembly]

[0133] <Comparative Example 1: Commercial Membrane-Electrode Assembly>

[0134] (a) Step: Preparation of polymer electrolyte membrane

[0135] A polymer electrolyte membrane was manufactured through a step of applying a polymer solution containing a solvent containing water and isopropanol in a weight ratio of 1:1 and perfluorosulfonic acid to a glass substrate using a doctor blade, and a step of slowly heating the applied polymer solution to 80°C and then drying it for 4 hours.

[0136] (b) Step: Fabrication of membrane-electrode assembly

[0137] A commercial Pt / C catalyst (10 g) from Tanaka was placed in a reaction vessel and mixed with a solvent to prepare a slurry. 45 parts by weight of an ion conductor dispersion (Nafion D-521), a binder, was added to the slurry based on 100 parts by weight of the catalyst (solid content), to prepare an electrode slurry. The electrode slurry was directly coated on both sides of the polymer electrolyte membrane to prepare a commercial membrane-electrode assembly including a catalyst layer.

[0138] <Example 1: Membrane-electrode assembly having a functional surface layer containing fluorinated carbon nanoparticles>

[0139] In the membrane-electrode assembly of Comparative Example 1, the composition according to Preparation Example 1 was coated on one side of the first catalyst layer (anode) by a spray method, and then dried at 80° C. for 3 minutes to form a first functional surface layer (fluorocarbon nanoparticle loading amount: about 0.51 mg / cm) having an area of ​​60% of the total active area. 2 , thickness: 1.0㎛) was formed. Next, in the membrane-electrode assembly of Comparative Example 1, a composition according to a separate Preparation Example 1 was coated on one side of the second catalyst layer (cathode) by a spray method, and then dried at 80°C for 3 minutes to form a second functional surface layer (fluorocarbon nanoparticle loading amount: about 0.70 mg / cm) having an area of ​​60% of the total active area of ​​the second catalyst layer. 2 , thickness: 1.5㎛) were formed. Here, the loading amount of each fluorinated carbon nanoparticle was calculated by measuring the weight change of the sample before / after loading the fluorinated carbon nanoparticle.

[0140] <Example 2: Membrane-electrode assembly having a functional surface layer containing boron nitride nanoparticles>

[0141] A membrane-electrode assembly was manufactured in the same manner as Example 1, but instead of the composition according to Preparation Example 1, the composition according to Preparation Example 2 was used. At this time, the loading amount of the boron nitride nanoparticles, the thickness of the first and second functional surface layers, and the occupied area of ​​the first and second functional surface layers based on the total active area were adjusted to be the same.

[0142] <Example 3: Membrane-electrode assembly having a functional surface layer including boron nitride nanoparticles>

[0143] A membrane-electrode assembly was manufactured in the same manner as Example 1, but instead of the composition according to Preparation Example 1, the composition according to Preparation Example 3 was used. At this time, the loading amount of the boron nitride fluoride nanoparticles, the thickness of the first and second functional surface layers, and the occupied area of ​​the first and second functional surface layers based on the total active area were adjusted to be the same.

[0144] <Example 4: Membrane-electrode assembly having a functional surface layer including a complex on the surface of an anode electrode>

[0145] In the membrane-electrode assembly of Comparative Example 1, the composition according to Preparation Example 4 was coated on one side of the first catalyst layer (anode) by a spray coating method, and then dried at 80° C. for 3 minutes to form a first functional surface layer (loading amount of the composite: about 0.51 mg / cm 2 , thickness: 1.0㎛) was formed. At this time, the occupied area of ​​the first functional surface layer was adjusted to 60% of the total active area.

[0146] [Experimental Example 1: SEM image and schematic diagram]

[0147] FIG. 5a is a scanning electron microscope (SEM) photograph of the surface of a membrane-electrode assembly manufactured according to Example 1, and FIG. 5b is a schematic diagram of FIG. 5a.

[0148] Fig. 6a is a scanning electron microscope (SEM) photograph of the surface of a membrane-electrode assembly manufactured according to Example 2, and Fig. 6b is a schematic diagram of Fig. 6a.

[0149] Fig. 7a is a scanning electron microscope (SEM) photograph of the surface of a membrane-electrode assembly manufactured according to Example 3, and Fig. 7b is a schematic diagram of Fig. 7a.

[0150] Fig. 8a is a surface scanning electron microscope (SEM) photograph of a membrane-electrode assembly manufactured according to Example 4, and Fig. 8b is a schematic diagram of Fig. 8a.

[0151] Referring to FIGS. 5 to 8, it can be confirmed that a functional surface layer is well introduced onto the surface of the membrane-electrode assembly of Examples 1 to 4. Specifically, referring to FIGS. 5b, 6b, 7b, and 8b, a catalyst layer (20) can be disposed on one surface of a polymer electrolyte membrane (10), and a functional surface layer (30) can be disposed on one surface of the catalyst layer.

[0152] [Experimental Example 2: Evaluation of Battery Output Performance of Membrane-Electrode Assemblies]

[0153] The output performance of the membrane-electrode assembly according to the above Manufacturing Example 1 was evaluated through IV measurement. Specifically, in order to confirm the output performance under actual fuel cell operating conditions, a fuel cell unit cell evaluation device (Scribner 850 fuel cell test system) including the membrane-electrode assembly was used. Hydrogen (100% RH) and air (100% RH) were supplied to the anode and cathode in amounts corresponding to the stoichiometry of 1.5 / 2.0 under 80°C conditions, respectively. The current density was measured when the voltage was 0.3 to 1.0 V, and a higher value indicates a better output performance. At this time, to evaluate the durability performance, 20,000 cycles were performed using the DOE catalyst durability evaluation protocol.

[0154] Figure 9 shows the results of performance evaluations of membrane-electrode assemblies manufactured according to comparative examples and examples at the beginning of life (BOL) and after durability evaluation (End of Life, EOL).

[0155] Referring to Fig. 9, it was confirmed that the membrane-electrode assemblies of Examples 1 to 3 had superior output performance both in the initial and after durability evaluation compared to the membrane-electrode assembly of Comparative Example 1.

[0156] [Experimental Example 3: Reverse Voltage Durability Evaluation]

[0157] For the membrane-electrode assembly according to Example 4, the reverse voltage durability was evaluated through a cell reversal test. Specifically, 50% RH air was supplied to the cathode, 50% RH nitrogen was supplied to the anode, and 0.2 A / cm 2 The reverse potential time, which is the time taken to reach -2.0 V while applying a current of , was measured. Referring to Table 1 below, fluorinated carbon nanoparticles and IrO x Example 4, which had a functional surface layer including a complex composed of nanoparticles (x=2), exhibited superior reverse potential durability with a higher reverse potential time compared to Comparative Example 1.

[0158] Sample - Time to reach 2.0 V (minutes) Comparative Example 13 Example 4187

[0159] [Experimental Example 4: Water-repellent performance evaluation]

[0160] The water repellent performance was evaluated by dropping a water droplet (10 μL / s) on the surface of the membrane-electrode assembly according to Manufacturing Example 1 at room temperature using a contact angle measuring device (equipment name: KRUSS DSA25) and measuring the contact angle of the dropped water droplet.

[0161] Sample contact angle (°) Comparative example 195 Example 1139 Example 2126 Example 3147 Example 4133

[0162] Referring to Table 2 above, Examples 1 to 4 having a water-repellent functional layer on the surface exhibited a larger contact angle than Comparative Example 1, indicating that they have excellent water-repellent performance. 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.

[0163] [Explanation of symbols]

[0164] CL: Catalyst layer for fuel cell 10: Polymer electrolyte membrane

[0165] 20: Catalyst layer 20a: First catalyst layer

[0166] 20b: Second catalyst layer 30: Functional surface layer

[0167] 30a: First functional surface layer 30b: Second functional surface layer

[0168] 100: Membrane-electrode assembly

Claims

1. Catalyst layer and Comprising a functional surface layer disposed on at least one surface of the catalyst layer, The above functional surface layer is, First fluorinated carbon nanoparticles; Boron nitride nanoparticles; Second fluorinated carbon nanoparticles and IrO x A composite comprising nanoparticles (x is 1, 2 or 3); and at least one functional nanoparticle selected from the group consisting of boron nitride nanoparticles; Catalyst layer for fuel cells.

2. In paragraph 1, Based on the total weight of the first fluorinated carbon nanoparticle, the fluorine content is 5 wt% or more and 90 wt% or less. Catalyst layer for fuel cells.

3. In paragraph 1, Based on the total weight of the above fluorinated boron nitride nanoparticles, the fluorine content is 5 wt% or more and 90 wt% or less. Catalyst layer for fuel cells.

4. In paragraph 1, The thickness of the above functional surface layer is 0.2 ㎛ or more and 2.0 ㎛ or less. Catalyst layer for fuel cells.

5. In paragraph 1, The above functional surface layer is, Covering 20% ​​or more and 80% or less of the total active area of ​​the surface in contact with the catalyst layer, Catalyst layer for fuel cells.

6. In paragraph 1, The above IrO x The nanoparticles (x is 1, 2 or 3) are supported on the second fluorinated carbon nanoparticles, Based on the total weight of the above complex, the IrO x The nanoparticle loading amount is 30 wt% or more and 75 wt% or less, Catalyst layer for fuel cells.

7. In paragraph 1, The loading amount of the above functional nanoparticles is 0.03 mg / cm 2 Above 1.0 mg / cm 2 Below, Catalyst layer for fuel cells.

8. Polymer electrolyte membrane; and A fuel cell catalyst layer according to claim 1, disposed on at least one surface of the polymer electrolyte membrane; Membrane electrode assembly.

9. In paragraph 8, The catalyst layer for the fuel cell is, Comprising a first catalyst layer disposed on one surface of the polymer electrolyte membrane, The above functional surface layer is, Comprising a first functional surface layer disposed on one surface of the first catalyst layer, The above first functional surface layer comprises the above complex, The above first catalyst layer is an anode, Membrane electrode assembly.

10. A fuel cell comprising a membrane electrode assembly according to paragraph 8.

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