High durable electrolyte membrane with improved ion conductivity and preparing method thereof

Abstract

The present invention relates to a highly durable electrolyte membrane with improved ion conductivity and a method for manufacturing the same. Specifically, the electrolyte membrane comprises an ionomer having hydrogen ion conductivity and a complex dispersed within the ionomer, wherein the complex comprises a support, a primary antioxidant supported on the support having radical capture ability, and a secondary antioxidant supported on the support having hydrogen peroxide decomposition activity.

Description

Technology Field

[0001] The present invention relates to a highly durable electrolyte membrane with improved ion conductivity and a method for manufacturing the same. Background Technology

[0002] Generally, Polymer Electrolyte Membrane Fuel Cells (PEMFCs) are used as fuel cells for automobiles. In order for these PEMFCs to normally exhibit high output performance of at least tens of kW or more under various driving conditions, they must be able to operate stably over a wide current density range. The reaction for generating electricity in the above fuel cell occurs in a membrane-electrode assembly (MEA) composed of a perfluorinated sulfonic acid (PFSA) ionomer-based membrane and an anode / cathode electrode. After hydrogen supplied to the anode, which is the oxidation electrode of the fuel cell, is separated into hydrogen ions (protons) and electrons, the hydrogen ions move through the membrane toward the cathode, which is the reduction electrode, and the electrons move toward the cathode through an external circuit. At the cathode, oxygen molecules, hydrogen ions, and electrons react together to generate electricity, while simultaneously producing water (H2O) and heat as reaction byproducts.

[0003] Typically, hydrogen and oxygen from the air, which are the reaction gases in fuel cells, crossover through the electrolyte membrane to promote the generation of hydrogen peroxide (HOOH). This hydrogen peroxide generates oxygen-containing radicals, such as hydroxyl radicals (·OH) and hydroperoxyl radicals (·OOH). These radicals attack perfluorosulfonic acid-based electrolyte membranes, causing chemical degradation of the membrane and ultimately having an adverse effect that reduces the durability of the fuel cell.

[0004] Conventionally, methods of adding various types of antioxidants to the electrolyte membrane have been proposed as techniques to mitigate the chemical degradation of such electrolyte membranes. These antioxidants include primary antioxidants with radical scavenger or quencher functions and secondary antioxidants with hydrogen peroxide decomposer functions, which can be used individually or in combination. Representative primary antioxidants used in perfluorosulfonic acid-based electrolyte membranes for polymer electrolyte membrane fuel cells include cerium-based and terephthalic acid-based antioxidants, such as cerium oxide (or ceria) and cerium (III) nitrate hexahydrate. The above cerium oxide can be broadly classified into pure cerium oxide (CeO2) and modified cerium oxide (Modified CeO2), and modified cerium oxide includes cerium-zirconium oxide (CeZrO2). x ), cerium-manganese oxide (CeMnO₂) xThere are ), cerium oxide-doped silica, cerium oxide-doped yttrium oxide, and cerium oxide-doped zirconium oxide.

[0005] In addition, representative secondary antioxidants used in perfluorosulfonic acid (PFSA) electrolyte membranes include manganese-based materials such as manganese oxide and transition metal catalysts such as platinum (Pt).

[0006] Various studies have been conducted on platinum-containing electrolyte membranes to enhance the chemical durability of fuel cell electrolyte membranes. Current research indicates that the durability of the electrolyte membrane can be improved or reduced depending on the amount, degree of distribution, and microstructure of the platinum introduced into the membrane. First, regarding positive effects, the platinum introduced into the membrane converts crossover hydrogen and oxygen gases into water before reaching the electrode, thereby increasing the amount of water within the membrane and enhancing proton conductivity, ultimately improving the performance of the membrane-electrode assembly. Additionally, by blocking crossover hydrogen and oxygen gases, it can have a positive effect on improving the chemical durability of the membrane by preventing radical generation itself or by decomposing hydrogen peroxide generated within the membrane. On the other hand, regarding negative effects, the platinum introduced into the membrane may convert hydrogen peroxide into radicals or directly convert crossover oxygen gases into radicals, consequently reducing the durability of the electrolyte membrane.

[0007] As described above, when platinum is added to an electrolyte membrane, it is generally added in a supported form on a support material to increase its dispersion, and the amount of platinum added is increased to further enhance the chemical durability of the electrolyte membrane. In this case, adding an excessive amount increases the risk of electrical short circuits in the electrolyte membrane due to the high electrical conductivity of platinum and carbon. Alternatively, the chemical durability of the electrolyte membrane can be improved by mixing and adding a radical scavenger. However, the hydrogen ion conductivity of the electrolyte membrane tends to decrease with the addition of the radical scavenger. Prior art literature

[0008] U.S. Patent No. 9,847,533 The problem to be solved

[0009] The present invention aims to provide an electrolyte membrane with excellent antioxidant properties and high hydrogen ion conductivity.

[0010] The objectives of the present invention are not limited to those mentioned above. The objectives of the present invention will become more apparent from the following description and will be realized by the means and combinations thereof described in the claims. means of solving the problem

[0011] An electrolyte membrane for a membrane-electrode assembly according to one embodiment of the present invention comprises an ionomer having hydrogen ion conductivity and a complex dispersed within the ionomer, wherein the complex may comprise a support; a primary antioxidant supported on the support having radical capture ability and a secondary antioxidant supported on the support having hydrogen peroxide decomposition activity.

[0012] The above support may include at least one selected from the group consisting of titanium nitride, titanium oxide, and combinations thereof.

[0013] The above support may contain titanium nitride within it and may contain titanium oxide on at least a portion of its surface.

[0014] The above support may be such that a peak attributed to titanium nitride; a peak attributed to titanium oxide of an anatase crystal structure; and a peak attributed to titanium oxide of a rutile crystal structure are found in the X-ray diffraction (XRD) pattern.

[0015] The above primary antioxidant may include at least one selected from the group consisting of cerium-based oxides, manganese-based oxides, and combinations thereof.

[0016] The content of the above primary antioxidant may be 3 μg / cm² to 35 μg / cm².

[0017] The above secondary antioxidant may include at least one selected from the group consisting of platinum (Pt), osmium (Os), iridium (Ir), gold (Au), palladium (Pd), silver (Ag), copper (Cu), nickel (Ni), cobalt (Co), titanium (Ti), iron (Fe), and combinations thereof.

[0018] The crystal size of the above secondary antioxidant may be 5 nm to 20 nm.

[0019] The density of the above secondary antioxidant may be 2 μg / cm³ to 4 μg / cm³.

[0020] The above electrolyte membrane further comprises a composite membrane including a reinforcing layer and an ion transfer material impregnated in the reinforcing layer, and an ion transfer layer formed on at least one surface of the composite membrane may include the ionomer and the composite.

[0021] A method for manufacturing an electrolyte membrane for a membrane-electrode assembly according to the present invention may include the steps of: supporting a secondary antioxidant having hydrogen peroxide decomposition activity on a support; supporting a primary antioxidant having radical capture ability on a support on which the secondary antioxidant is supported to obtain a complex; and applying a mixture obtained by dispersing the complex in an ionomer to manufacture an electrolyte membrane.

[0022] The above support comprises titanium nitride, and before supporting the primary antioxidant, the support on which the secondary antioxidant is supported can be dried in an atmospheric environment to oxidize the support.

[0023] The oxidized support may contain titanium nitride within it and titanium oxide on at least a portion of its surface.

[0024] The above drying can be performed at 60°C to 100°C.

[0025] The above drying can be performed within 60 minutes from the time the secondary antioxidant reacts with the air in the atmosphere.

[0026] An ion-transfer layer can be formed by applying the above mixture to at least one surface of a composite membrane comprising a reinforcing layer and an ion-transfer material impregnated in the reinforcing layer. Effects of the invention

[0027] According to the present invention, by adding a complex in which a secondary antioxidant with hydrogen peroxide decomposition activity and a primary antioxidant with radical capture ability are complexly supported, an electrolyte membrane with improved chemical durability and improved hydrogen ion conductivity can be obtained.

[0028] According to the present invention, an electrolyte membrane with improved chemical durability can be obtained without a reduction in overall performance.

[0029] The effects of the present invention are not limited to those mentioned above. It should be understood that the effects of the present invention include all effects that can be inferred from the following description. Brief explanation of the drawing

[0030] FIG. 1 is a cross-sectional view illustrating a first embodiment of an electrolyte membrane for membrane-electrode junction according to the present invention. Figure 2 is a cross-sectional view illustrating the above electrolyte membrane complex. FIG. 3 is a cross-sectional view illustrating a second embodiment of an electrolyte membrane according to the present invention. Figure 4 shows the results of X-ray diffraction (XRD) analysis performed on the products of the manufacturing example and the comparative manufacturing example. Figure 5 shows the results of measuring the hydrogen ion conductivity of Example 1 and Comparative Example 1. Figure 6 shows the results of measuring the performance of Example 2 and Comparative Example 2. Specific details for implementing the invention

[0031] The above objects, other objects, features, and advantages of the present invention will be easily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete, and to ensure that the spirit of the invention is sufficiently conveyed to a person skilled in the art.

[0032] In describing each drawing, similar reference numerals have been used for similar components. In the attached drawings, the dimensions of the structures are depicted enlarged from their actual size for clarity of the invention. Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the invention, the first component may be named the second component, and similarly, the second component may be named the first component. A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0033] In this specification, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Furthermore, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only the case where it is "immediately above" the other part, but also the case where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only the case where it is "immediately below" the other part, but also the case where there is another part in between.

[0034] Unless otherwise specified, all numbers, values, and / or expressions used herein to represent amounts of ingredients, reaction conditions, polymer compositions, and formulations should be understood to be modified by the term “approximately” in all cases, as these numbers are essentially approximations reflecting the various uncertainties of measurement that occur in obtaining these values ​​among other things. Furthermore, where numerical ranges are disclosed herein, such ranges are continuous and, unless otherwise indicated, include all values ​​from the minimum value of such range to the maximum value including said maximum value. Moreover, where such ranges refer to integers, they include all integers from the minimum value to said maximum value including said maximum value, unless otherwise indicated.

[0036] FIG. 1 is a cross-sectional view illustrating a first embodiment of an electrolyte membrane for membrane-electrode junction according to the present invention. Referring thereto, the electrolyte membrane comprises an ionomer (10) and a composite (20) dispersed in the ionomer (10).

[0037] The above ionomer (10) is a component that serves as a type of substrate forming the shape of the electrolyte membrane.

[0038] The above ionomer (10) includes a material that is hydrogen ion conductive. Therefore, hydrogen ions can move between a pair of electrodes formed on both sides of the electrolyte membrane. The type of the ionomer (10) is not particularly limited, but may include, for example, a perfluorosulfonic acid-based polymer such as Nafion.

[0039] FIG. 2 is a cross-sectional view illustrating the composite (20). Referring to the figure, the composite (20) comprises a support (21) and a primary antioxidant (22) and a secondary antioxidant (23) supported on the support (21).

[0040] The above support (21) includes a non-conductive material. Here, “non-conductive material” means a material that has no electrical conductivity or has electrical conductivity to the extent that it does not affect the electrical conductivity of the electrolyte membrane.

[0041] The support (21) may include at least one selected from the group consisting of titanium nitride (TiN), titanium oxide (TiO2), and combinations thereof. Specifically, the support (21) may include titanium nitride in its interior (21a) and titanium oxide in at least a portion of its surface (21b). However, this does not mean that the interior (21a) is composed solely of titanium nitride and the surface (21b) is composed solely of titanium oxide. Titanium oxide may be included in the interior (21a) and titanium nitride may be included in the surface (21b). That is, when viewed as a whole, the main component of the interior (21a) is titanium nitride, and at least a portion of the surface (21b) may contain titanium oxide formed by the oxidation of the titanium nitride.

[0042] The specific surface area of ​​the support (21) is not particularly limited, but for example, 50 m 2 / g or more, or 100 m 2 / g. The specific surface area of ​​the support (21) can be appropriately adjusted according to the loading amount of the primary antioxidant, the loading amount of the second antioxidant, etc.

[0043] The above primary antioxidant is a substance having radical scavenging ability and may include at least one selected from the group consisting of cerium-based oxides, manganese-based oxides, and combinations thereof.

[0044] The content of the primary antioxidant may be 3 µg / cm² to 35 µg / cm² or 5 µg / cm² to 30 µg / cm² in the dried electrolyte membrane. If the content of the primary antioxidant is less than 3 µg / cm², the degree of improvement in the chemical durability of the electrolyte membrane may be negligible, and if it exceeds 35 µg / cm², the hydrogen ion conductivity of the electrolyte membrane may decrease rapidly.

[0045] The above secondary antioxidant is a substance having hydrogen peroxide decomposition activity and may include at least one selected from the group consisting of platinum (Pt), osmium (Os), iridium (Ir), gold (Au), palladium (Pd), silver (Ag), copper (Cu), nickel (Ni), cobalt (Co), titanium (Ti), iron (Fe), and combinations thereof.

[0046] The crystal size of the secondary antioxidant may be 5 nm to 20 nm, or 8 nm to 15 nm. If the crystal size of the secondary antioxidant is less than 5 nm, it may leach out when the electrolyte membrane is used, which may reduce the chemical durability of the electrolyte membrane, and if it exceeds 20 nm, the degree of improvement in the chemical durability of the electrolyte membrane may be negligible compared to the amount added.

[0047] The density of the secondary antioxidant may be 2 μg / cm³ to 4 μg / cm³ or 2.5 μg / cm³ to 3.5 μg / cm³ in the dried electrolyte membrane. The “density of the secondary antioxidant” refers to the value obtained by dividing the secondary antioxidant content (μg / cm²) by the thickness of the electrolyte membrane containing the secondary antioxidant. If the density of the secondary antioxidant is less than 2 μg / cm³, the effect of increasing the open-circuit voltage of the membrane-electrode assembly is negligible, so the effect of increasing the long-term chemical durability of the electrolyte membrane is not significant, and if it exceeds 4 μg / cm³, there may be problems with a decrease in open-circuit voltage and a decrease in hydrogen ion conductivity due to the over-densification of the conductive material.

[0048] FIG. 3 is a cross-sectional view illustrating a second embodiment of an electrolyte membrane according to the present invention. Referring thereto, the electrolyte membrane comprises a composite membrane (30) comprising a reinforcing layer (31) and an ion transfer material (32) impregnated in the reinforcing layer (31), and an ion transfer layer (40) formed on at least one surface of the composite membrane (30). The ion transfer layer (40) comprises the aforementioned ionomer (10) and the composite (40).

[0049] The reinforcing layer (31) is configured to increase the mechanical strength of the electrolyte membrane. Since the reinforcing layer (31) is a porous membrane containing a plurality of pores, it may be impregnated with an ion transfer material (32).

[0050] The reinforcing layer (31) may include at least one selected from the group consisting of polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (e-PTFE), polyethylene (PE), polypropylene (PP), polyphenylene oxide (PPO), polybenzimidazole (PBI), polyimide (PI), polyvinylidene fluoride (PVdF), polyvinyl chloride (PVC) and combinations thereof.

[0051] The above ion transfer material (32) is configured to be impregnated into the reinforcing layer (31) to transfer hydrogen ions. As shown in FIG. 3, the ion transfer material (32) may fill the internal pores of the reinforcing layer (31) and form a layer of a predetermined thickness on both sides of the reinforcing layer (31). However, the ion transfer material (32) may form a layer on only one side of the reinforcing layer (31), or it may fill only the internal pores of the reinforcing layer (31) and not form a layer on the outside.

[0052] The above ion transfer material (32) may include any material capable of transferring hydrogen ions. Additionally, it may be the same or different material as the ionomer (10), but preferably it may be a perfluorosulfonic acid-based polymer identical to the ionomer (10).

[0053] The ionomer (10) and the composite (20) included in the above ion transfer layer (40) have been described above, so they will be omitted below.

[0055] A method for manufacturing an electrolyte membrane according to the present invention comprises the steps of: supporting a secondary antioxidant having hydrogen peroxide decomposition activity on a support; supporting a primary antioxidant having radical scavenging ability on a support on which the secondary antioxidant is supported to obtain a complex; and applying a mixture obtained by dispersing the complex in an ionomer to manufacture an electrolyte membrane.

[0056] The method of supporting the secondary antioxidant and the primary antioxidant on the above support is not particularly limited and may include any method widely used in the technical field to which the present invention belongs, such as polyol synthesis methods and hydrothermal synthesis methods.

[0057] The above manufacturing method further includes the step of oxidizing the support loaded with the secondary antioxidant by drying the support in an atmospheric atmosphere before loading the primary antioxidant. Accordingly, the crystal size of the secondary antioxidant can be increased, and titanium oxide can be formed on at least a portion of the surface of the support containing titanium nitride.

[0058] The above drying can be performed at 60°C to 100°C.

[0059] In addition, the drying can be performed within 60 minutes from the time when the secondary antioxidant reacts with air in the atmosphere and ignites. If the drying is terminated before the secondary antioxidant ignites, there may be no change in the surface of the titanium nitride, and the effect of improving the hydrogen ion conductivity of the electrolyte membrane may be minimal. If the drying time exceeds 60 minutes from the time of ignition, the particles of the secondary antioxidant may grow excessively or the titanium nitride may all change into an oxide form, which may reduce corrosion resistance and antioxidant properties.

[0060] Meanwhile, a mixture obtained by dispersing the above-mentioned composite in an ionomer may be applied to at least one surface of a composite membrane comprising the aforementioned reinforcing layer and ion transfer material to form an ion transfer layer.

[0062] The present invention will be explained in more detail through the following examples. However, the following examples are merely illustrative to aid in understanding the present invention, and the scope of the present invention is not limited thereto.

[0064] Preparation Example

[0065] The support structure has a specific surface area of ​​approximately 50 m² 2 Titanium nitride with a content of 1 / g was prepared. A precursor of platinum, which is a secondary antioxidant, was mixed into a dispersion of the support and heated to approximately 160°C. Subsequently, sodium hydroxide (NaOH) was added to adjust the pH to 10–11, and the reaction was carried out for 5 to 10 hours. Then, a sulfuric acid solution was added to adjust the pH to 2–3, and the reaction was carried out. The resulting product was washed with distilled water, and a powder was obtained by centrifugation. The powder was dried at 80°C in an atmospheric environment. The powder is titanium nitride with platinum supported thereon. The powder was dried for approximately 60 minutes from the point at which the platinum began to ignite upon reacting with air in the atmosphere, thereby increasing the crystal size of the platinum and oxidizing the titanium nitride. The resulting product is hereinafter referred to as Pt / TiN-Oxidized.

[0067] Comparative Manufacturing Example

[0068] Platinum was supported on titanium nitride in a manner similar to the above manufacturing example. However, the platinum support process was controlled to prevent oxidation of the support. The resulting product is hereinafter referred to as Pt / TiN.

[0070] Experimental Example 1

[0071] X-ray diffraction (XRD) analysis was performed on the results of the above-mentioned preparation example and comparative preparation example. The results are shown in Figure 4. Referring to this, it can be seen that the Pt / TiN-Oxidized of the preparation example exhibits peaks attributed to titanium nitride, peaks attributed to titanium oxide with an anatase crystal structure, and peaks attributed to titanium oxide with a rutile crystal structure.

[0072] In addition, the platinum crystal size of the manufacturing example calculated based on the above X-ray diffraction analysis results was 11.6 nm, and the platinum crystal size of the comparative manufacturing example was 3 nm.

[0074] Example 1 and Comparative Example 1

[0075] A primary antioxidant was loaded onto the products according to the above preparation examples and comparative preparation examples in the following manner. Each product was added to a cerium precursor dispersion and dried by a hydrothermal reaction at approximately 100°C, and then heat-treated at approximately 180°C for approximately 2 hours to load cerium oxide.

[0076] Each composite obtained as described above was added to and dispersed in a perfluorosulfonic acid-based ionomer. After applying the dispersion onto a substrate, the electrolyte membrane was prepared by drying at approximately 80°C for 2 to 12 hours and heat-treating at approximately 160°C for 5 minutes. The electrolyte membrane using the product of the preparation example is defined as Example 1, and the electrolyte membrane using the product of the comparative preparation example is defined as Comparative Example 1.

[0077] The hydrogen ion conductivity of Example 1 and Comparative Example 1 was measured. Hydrogen ion conductivity was measured from 40°C to 80°C under conditions of 50% relative humidity. The results are shown in Fig. 5. Referring to this, it can be seen that Example 1 has higher hydrogen ion conductivity than Comparative Example 1 across the entire range. In particular, at a measurement temperature of 80°C, the hydrogen ion conductivity of Comparative Example 1 was 23.4 mS / cm², while the hydrogen ion conductivity of Example 1 was significantly improved to 39.2 mS / cm².

[0079] Example 2 and Comparative Example 2

[0080] Each dispersion used in Example 1 and Comparative Example 1 was applied and dried on a composite membrane comprising a reinforcing layer and an ion transfer material impregnated therewith to form an electrolyte membrane as shown in FIG. 3. These are defined as Example 2 and Comparative Example 2, respectively.

[0081] A membrane-electrode assembly was prepared by forming electrodes on both sides of the electrolyte membranes of Example 2 and Comparative Example 2, and its performance was measured. The results are shown in Fig. 6. In addition, the physical properties of Example 2 and Comparative Example 2 are summarized in Table 1 below.

[0082] division Platinum content [mg / cm²] 2 ] Platinum density [µg / cm³] Cerium content*[㎍ / ㎠] Open circuit voltage [V] Performance [V@1.0A / cm 2 ] Comparative Example 2 0.19 1.9 35.3 0.977 0.614 Example 2 0.022 2.8 16.3 0.996 0.649

[0083] The above cerium content refers to the cerium content contained in cerium oxide.

[0084] Comparative Example 2 had an Open Circuit Voltage (OCV) of 0.977 V and a performance of 0.614 V at a current density of 1.0 A / cm². Additionally, Example 2 had an Open Circuit Voltage (OCV) of 0.996 V and a performance of 0.649 V at a current density of 1.0 A / cm². It can be seen that the increase in Open Circuit Voltage is clearly manifested when the platinum density exceeds 2 μg / cm³, and that the performance of the membrane-electrode assembly decreases rapidly when the cerium content exceeds approximately 17 μg / cm².

[0086] As the experimental examples and embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to the aforementioned experimental examples and embodiments, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also included within the scope of the present invention. Explanation of the symbols

[0087] 10: Ionomer 20: Complex 21: Support 22: Primary antioxidant 23: Secondary antioxidant 30: Composite membrane 31: Reinforcement layer 32: Ion transport material 40: Ion transport layer

Claims

Claim 1 An electrolyte membrane for a membrane-electrode assembly comprising: an ionomer having hydrogen ion conductivity; and a complex dispersed within the ionomer; wherein the complex comprises a support; a primary antioxidant supported on the support and having radical capture ability; and a secondary antioxidant supported on the support and having hydrogen peroxide decomposition activity; and wherein the support comprises titanium nitride and titanium oxide. Claim 2 delete Claim 3 An electrolyte membrane for a membrane-electrode assembly according to claim 1, wherein the support comprises titanium nitride within and titanium oxide on at least a portion of its surface. Claim 4 The electrolyte membrane for a membrane-electrode assembly according to claim 1, wherein the support is found to have a peak attributable to titanium nitride in an X-ray diffraction (XRD) pattern; a peak attributable to titanium oxide of an anatase crystal structure; and a peak attributable to titanium oxide of a rutile crystal structure. Claim 5 An electrolyte membrane for a membrane-electrode assembly according to claim 1, wherein the primary antioxidant comprises at least one selected from the group consisting of cerium-based oxides, manganese-based oxides, and combinations thereof. Claim 6 An electrolyte membrane for a membrane-electrode assembly according to claim 1, wherein the content of the primary antioxidant is 3 μg / cm² to 35 μg / cm². Claim 7 An electrolyte membrane for a membrane-electrode assembly according to claim 1, wherein the secondary antioxidant comprises at least one selected from the group consisting of platinum (Pt), osmium (Os), iridium (Ir), gold (Au), palladium (Pd), silver (Ag), copper (Cu), nickel (Ni), cobalt (Co), titanium (Ti), iron (Fe), and combinations thereof. Claim 8 An electrolyte membrane for a membrane-electrode assembly according to claim 1, wherein the crystal size of the secondary antioxidant is 5 nm to 20 nm. Claim 9 An electrolyte membrane for a membrane-electrode assembly according to claim 1, wherein the density of the secondary antioxidant is 2 μg / cm³ to 4 μg / cm³. Claim 10 The electrolyte membrane for a membrane-electrode assembly according to claim 1, further comprising a composite membrane including a reinforcing layer and an ion-transferring material impregnated in the reinforcing layer, wherein the ion-transferring layer formed on at least one surface of the composite membrane comprises the ionomer and the composite. Claim 11 A fuel cell comprising an electrolyte membrane according to any one of claims 1 and 3 through 10. Claim 12 A water electrolysis device comprising an electrolyte membrane according to any one of claims 1 and 3 through 10. Claim 13 A method for manufacturing an electrolyte membrane for a membrane-electrode assembly comprising: a step of supporting a secondary antioxidant having hydrogen peroxide decomposition activity on a support; a step of supporting a primary antioxidant having radical capture ability on a support supported with the secondary antioxidant to obtain a complex; and a step of dispersing the complex in an ionomer to obtain a mixture and applying it to manufacture an electrolyte membrane; wherein the support comprises titanium nitride, and prior to supporting the primary antioxidant, the support supported with the secondary antioxidant is dried in an atmospheric atmosphere to oxidize the support, and the oxidized support comprises titanium nitride and titanium oxide. Claim 14 delete Claim 15 A method for manufacturing an electrolyte membrane for a membrane-electrode assembly according to claim 13, wherein the oxidized support comprises titanium nitride within and titanium oxide on at least a portion of its surface. Claim 16 A method for manufacturing an electrolyte membrane for a membrane-electrode assembly, wherein, in claim 13, the drying is performed at 60°C to 100°C. Claim 17 A method for manufacturing an electrolyte membrane for a membrane-electrode assembly according to claim 13, wherein the drying is performed within 60 minutes from the time the secondary antioxidant reacts with air in the atmosphere. Claim 18 A method for manufacturing an electrolyte membrane for a membrane-electrode assembly according to claim 13, wherein the above mixture is applied to at least one surface of a composite membrane comprising a reinforcing layer and an ion-transferring material impregnated in the reinforcing layer to form an ion-transferring layer.

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