KR20160039375A - Electrolyte membrane for fuel cell and preparation method thereof - Google Patents

Abstract

According to the present invention, there is provided an electrolyte membrane for a fuel cell and a method of manufacturing the same. The electrolyte membrane for a fuel cell provided with the present invention can provide a fuel cell exhibiting improved durability and stable performance by providing a radical scavenger layer containing a plurality of metal oxide nanosheets.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrolyte membrane for a fuel cell,

According to the present invention, there is provided an electrolyte membrane for a fuel cell having a radical scavenger layer, a method for producing the electrolyte membrane, and a membrane-electrode assembly including the electrolyte membrane and a fuel cell.

A fuel cell is an electrochemical cell that converts chemical energy into electrical energy by electrochemical reaction of hydrogen or alcohol as fuel and oxygen or air as oxidant. A fuel cell includes an anode and a cathode separated by an electrolyte.

A proton exchange membrane (PEM) fuel cell in a fuel cell includes a solid polymer membrane as an electrolyte. The electrolyte is a film that is electrically insulating but ion conductive. The protons generated in the anode pass through the membrane to the cathode, and combine with oxygen to produce water.

Such a PEM fuel cell has a low operating temperature (about 80 ° C), high efficiency, large current density and power density, short startup time, and quick response characteristics in response to load changes compared with other types of fuel cells. Particularly, since the solid polymer membrane is used as the electrolyte, the PEM fuel cell has less fear of corrosion, does not require the control of the electrolyte, and is less sensitive to changes in the pressure of the reaction gas. In addition, the PEM fuel cell has a simple structure, is easy to manufacture, and can output a wide range of output. Thus, the PEM fuel cell has been applied to a variety of fields such as a power source for a pollution-free vehicle, a locally installed power source, a mobile power source, and a military power source.

The characteristics of the electrolyte membrane in the PEM fuel cell are mainly evaluated in terms of ion exchange capacity (IEC) or equivalent weight (EW) and generally require high proton conductivity, mechanical strength, low gas permeability and water permeability. In particular, since the proton conductivity drops sharply during dehydration, the electrolyte membrane must be resistant to dehydration. In addition, the electrolyte membrane should have high resistance to oxidation, reduction, hydrolysis, and the like, have good cation binding ability, and have durability to maintain these properties for a predetermined period of time.

The electrolyte membrane used in the PEM fuel cell may be classified into a perfluorocarbon, a partial fluorine, and a hydrocarbon. Of these, Nafion® from Dufont, Aciplex® from Asahi Chemical, and Flemion® from Asahi Glass have been commercialized with excellent proton conductivity and chemical stability. However, the commercially available perfluorinated electrolyte membrane has a disadvantage in that it has high hydrogen ion permeability and physical or chemical stability during long-time operation, resulting in deterioration of battery performance.

On the other hand, when the PEM fuel cell is driven, peroxy and hydroperoxy radicals are formed by the reaction of oxygen and hydrogen penetrating through the electrolyte membrane. However, due to such radicals, the electrolyte membrane is chemically attacked, shortening or destroying its service life. There have been various attempts to impart internal radical resistance, such as impregnating or coating a radical scavenger inside the electrolyte membrane.

However, in these prior arts, since the radical scavenger is impregnated or coated in the ion conductive membrane in the form of particles, the radical scavenger is not fixed in the electrolyte membrane, and there is a possibility that the radical scavenger leaks due to swelling or flooding of the electrolyte membrane . In addition, the electrolyte membrane impregnated or coated with the particle-type radical scavenger has a problem that the radical scavenger is poor in the portion where the radical scavenger particle is not present because the distribution of the radical scavenger is not uniform.

The present invention is intended to provide an electrolyte membrane for a fuel cell having improved internal resistance.

The present invention also provides a method of manufacturing the electrolyte membrane for a fuel cell.

The present invention also provides a membrane-electrode assembly including the electrolyte membrane and a fuel cell.

According to the present invention,

Ion conductive membrane; And

A radical trapping layer containing a plurality of metal oxide nanosheets laminated on at least one surface of the ion conductive membrane

An electrolyte membrane for a fuel cell is provided.

Further, according to the present invention,

Preparing a composition for forming a radical scavenger layer including a metal oxide nanosheet;

Forming a coating layer of the composition for forming a radical scavenger layer on at least one side of the ion conductive membrane; And

And drying the coating layer to form a radical scavenger layer containing a plurality of metal oxide nanosheets

A method for manufacturing an electrolyte membrane for a fuel cell is provided.

According to the present invention, there is provided a membrane-electrode assembly for a fuel cell comprising an electrolyte catalyst layer and an electrode catalyst layer provided on both surfaces of the electrolyte membrane and the electrolyte membrane. Further, according to the present invention, there is provided a fuel cell including the membrane-electrode assembly.

Hereinafter, an electrolyte membrane for a fuel cell according to embodiments of the present invention, a method of manufacturing the same, and the like will be described in detail.

Prior to that, and unless explicitly stated throughout the present specification, the terminology is used merely to refer to a specific embodiment and is not intended to limit the present invention. And, the singular forms used herein include plural forms unless the phrases expressly have the opposite meaning. Also, as used herein, the term " comprises " embodies certain features, areas, integers, steps, operations, elements and / or components, It does not exclude the existence or addition of a group.

In this specification, the term 'metal oxide nanosheet' refers to a metal oxide in the form of a sheet having a nanometer scale thickness. For example, the metal oxide nanosheets can be formed by agglomeration through reaction of particulate metal oxide with optional additives.

I. Electrolyte Membrane for Fuel Cell

According to one embodiment of the invention,

Ion conductive membrane; And

A radical trapping layer containing a plurality of metal oxide nanosheets laminated on at least one surface of the ion conductive membrane

An electrolyte membrane for a fuel cell is provided.

As a result of continuous experiments conducted by the inventors of the present invention, it has been confirmed that when a radical scavenger layer containing a plurality of metal oxide nanosheets is formed on an ion conductive membrane, an electrolyte membrane having improved internal radical resistance can be provided.

In this regard, the electrolyte membrane for a fuel cell proposed so far has a form in which the radical scavenger on the particle is impregnated or coated in the ion conductive membrane. For example, FIG. 1 (a) shows a cross-section of an electrolyte membrane 100 having a form in which a radical scavenger layer 10 including metal oxide particles 1 is coated on an ion conductive membrane 20 . However, in this type of electrolyte membrane, the ion conductive membrane 20 is chemically attacked by the radical (R) penetrating through the region where the metal oxide particle 1 does not exist. This type of electrolyte membrane can not be fixed on the radical scavenger layer 10 or the ion conductive membrane 20, but can be flowed out by swelling, flooding, or the like, so that sufficient internal resistance is secured There is a problem that can not be done.

Alternatively, the electrolyte membrane provided by the present invention has a structure in which the metal oxide, which is a radical scavenger, is laminated in the form of a plurality of sheets (hereinafter referred to as 'nanosheets') having a nanometer scale thickness to form a radical scavenger layer. For example, an electrolyte membrane according to an embodiment of the present invention may be formed by stacking a plurality of metal oxide nanosheets 2 on an ion conductive membrane 20 to form a radical scavenger layer 10, as shown in FIG. 1 (b) Structure. Thereby, the ion conductive membrane 20 can be effectively protected from the chemical attack of the radical by the plurality of metal oxide nanosheets 2, and an electrolyte membrane having improved inner resistance can be provided.

In an embodiment of the present invention, the ion conductive membrane 20 is a polymer membrane having electrical insulation and ionic conductivity, and may be formed from an ionomer that is conventional in the art. As a non-limiting example, the ion conductive membrane may be formed from a fluorine-based polymer or a hydrocarbon-based polymer. Specifically, the ion conductive membrane may be formed of a perfluoro proton conductive polymer, a sulfonated polysulfone copolymer, a sulfonated poly (ether-ketone) based polymer, a sulfonated polyether ether ketone based polymer, Based polymer may be one formed from at least one ionomer selected from the group consisting of a polyimide-based polymer, a polystyrene-based polymer, a polysulfone-based polymer, and a clay-sulfonated polysulfone nanocomposite.

On the other hand, a radical scavenger layer 10 including a plurality of metal oxide nanosheets 2 is formed on at least one surface of the ion conductive membrane. FIG. 3 is an enlarged image of a surface of a metal oxide nanosheet 2 formed according to an embodiment of the present invention, wherein the radical scavenger layer 10 is formed of a plurality of sheets of metal oxide having a nanometer- As shown in FIG.

Here, the thickness of the metal oxide nanosheet and the number of layers to be laminated are not particularly limited. However, it is advantageous that the radical scavenger layer 10 including the metal oxide nanosheets has an average thickness of 5 to 1000 nm or 50 to 800 nm. That is, the radical scavenger layer 10 preferably has an average thickness of 5 nm or more, so that the inner radical properties can be appropriately exerted. However, if the thickness of the radical scavenger layer is too thick, the performance of the membrane-electrode assembly may deteriorate, and the recent trend of improving the performance of a battery using a thin electrolyte membrane may not be satisfied. Therefore, the radical scavenger layer 10 preferably has an average thickness of 1000 nm or less.

The metal oxide contained in the radical scavenger layer (that is, the metal oxide nanosheet) is a metal oxide which can decompose peroxyl radicals and hydroperoxy radicals formed by the reaction of oxygen and hydrogen into water and oxygen Radical scavenger. Specifically, these metal oxides may be selected from the group consisting of silicon oxide, titanium oxide, aluminum oxide, manganese oxide, cerium oxide, iridium oxide, beryllium oxide, zirconium oxide, beryllium oxide, bismuth oxide, gallium oxide, germanium oxide, tantalum oxide, Hafnium oxide, vanadium oxide, and lanthanum oxide.

Alternatively, the radical scavenger layer may include an ionomer as a binder. The ionomer may be a conventional ion conductive polymer. Preferably, the ionomer is a polymer containing a perfluorinated sulfonic acid group, a perfluorinated proton conductive polymer, a sulfonated polysulfone copolymer, a sulfonated poly (ether-ketone) And at least one polymer selected from the group consisting of a polyether ether ketone polymer, a polyimide polymer, a polystyrene polymer, a polysulfone polymer, and a clay-sulfonated polysulfone nanocomposite.

The content of the ionomer may be controlled to 0.1 to 100 parts by weight based on 100 parts by weight of the metal oxide nanosheet. That is, the ionomer is a component that allows a plurality of metal oxide nanosheets to be stacked more stably, and its content can be adjusted as needed. However, if an excess amount of ionomer is added to the radical scavenger layer, the metal oxide may be dispersed in the form of particles or the adhesion of the metal oxide nanosheets may be deteriorated, so that the intrinsic radical properties required in the present invention may not be sufficiently exhibited. Accordingly, when the ionomer is added to the radical scavenging agent layer, the ionomer is preferably included in an amount of 100 parts by weight or less based on 100 parts by weight of the metal oxide nanosheet.

According to an embodiment of the present invention, an ionomer layer (not shown) may further be formed on the radical scavenger layer.

The ionomer layer may be laminated for the purpose of protecting the radical scavenger layer and separating from the electrode catalyst layer. This ionomer layer may be formed on the other surface of the radical scavenger layer not in contact with the ion conductive membrane. The ionomer layer may be formed using the ion conductive polymers described above, and the average thickness may be 100 to 2000 nm. That is, it is preferable that the ionomer layer has an average thickness of 100 nm or more so that the effect of the formation of the ionomer layer can be properly exhibited. However, if the thickness of the ionomer layer is too thick, the performance of the membrane-electrode assembly may deteriorate, and the recent trend of improving the performance of the battery using a thin electrolyte membrane may not be satisfied. Therefore, when it is desired to include an ionomer layer in the electrolyte membrane, the ionomer layer preferably has an average thickness of 2000 nm or less.

Such an electrolyte membrane can be applied to a membrane-electrode assembly of a fuel cell to exhibit improved internal resistance. However, the electrolyte membrane can be applied to an energy storage or production apparatus such as a solar cell, a secondary battery, and a supercapacitor in addition to the fuel cell field. Also, the electrolyte membrane can be applied to an organic electroluminescent device.

II . Method for manufacturing electrolyte membrane for fuel cell

On the other hand, according to another embodiment of the invention,

Preparing a composition for forming a radical scavenger layer including a metal oxide nanosheet;

Forming a coating layer of the composition for forming a radical scavenger layer on at least one side of the ion conductive membrane; And

And drying the coating layer to form a radical scavenger layer containing a plurality of metal oxide nanosheets

A method for manufacturing an electrolyte membrane for a fuel cell is provided.

The composition for forming a radical scavenger layer includes a metal oxide as a radical scavenger, and an additive that enables the metal oxide to form a nanosheet phase is used. That is, the metal oxide nanosheet may be formed by reacting the metal oxide and the additive in water or a conventional organic solvent. Through this reaction, the metal oxide is present in the composition in the form of nanosheets. The additive is removed after the metal oxide nanosheet is formed.

The metal oxide may be at least one selected from the group consisting of silicon oxide, titanium oxide, aluminum oxide, manganese oxide, cesium oxide, iridium oxide, beryllium oxide, zirconium oxide, beryllium oxide, bismuth oxide, gallium oxide, germanium oxide, tantalum oxide , Niobium oxide, hafnium oxide, vanadium oxide, and lanthanum oxide.

The additive is selected from the group consisting of tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPAOH), and tetrabutylammonium hydroxide (TBAOH) More than one species of compound may be used.

As described above, the radical scavenger layer may further contain an ionomer as a binder. In this case, a solution in which an ionomer is dissolved or dispersed may be prepared by mixing the composition with the composition for forming a radical scavenger layer. The content of the ionomer may be controlled to 0.1 to 100 parts by weight based on 100 parts by weight of the metal oxide nanosheet. In addition, ultrasonic vibration stirring can be performed for even mixing of the ionomer and the metal oxide nanosheet.

On the other hand, the step of forming the coating layer of the composition for forming a radical scavenger layer on at least one side of the ion conductive film can be performed by a conventional technique (for example, spraying, screen printing, inkjet printing, dipping, bar coating, cap coating, Coating, slot die coating, gravure coating, etc.). Here, the thickness of the coating layer may be controlled according to the type and content of the solvent contained in the composition, whether or not the ionomer is added, and the like within a range of 5 to 1000 nm in thickness after drying.

According to an embodiment of the present invention, if necessary, a step of forming a coating layer of the ionomer solution on the coating layer of the composition for forming a radical scavenger layer may be further performed. The coating layer of the ionomer solution is a coating layer for forming an ionomer layer (not shown in the figure) on the radical scavenger layer as described above. The ionomer solution may be prepared by dissolving or dispersing the above ion conductive polymer in water or a conventional organic solvent. The coating technique described above may be applied to form the coating layer of the ionomer solution. The thickness of the coating layer of the ionomer solution may be controlled according to the kind of ionomer contained in the ionomer solution, the type and content of the solvent, and the like within a range of 100 to 2000 nm in thickness after drying. According to the embodiment of the present invention, it is preferable that the coating layer of the composition for forming a radical scavenger layer and the coating layer of the ionomer solution are sequentially formed on the ion conductive film, and then the coating layers are dried together . However, the coating layer may be separately formed and dried.

Meanwhile, a step of drying a coating layer of the composition for forming a radical scavenger layer to form a radical scavenger layer containing a plurality of metal oxide nanosheets is performed.

According to an embodiment of the invention, the drying can be carried out through a plurality of steps so that a radical scavenger layer and / or an ionomer layer with improved physical properties can be formed. Specifically, the drying may be performed in sequence by a first heat treatment step performed at 20 to 100 ° C for 1 to 24 hours and a second heat treatment step performed at 120 to 250 ° C for 0.5 to 10 minutes. The residual solvent contained in the coating layer can be sufficiently removed through the first and second heat treatment processes and a plurality of metal oxide nanosheets can be stacked more stably on the ion conductive film to form a radical trapping agent layer of uniform thickness . In addition, when an ionomer is used, the thermal curing of the ionomer can be sufficiently performed through the plurality of heat treatment processes.

III . Membrane-electrode assemblies and fuel cells

According to another embodiment of the present invention, there is provided a membrane-electrode assembly for a fuel cell comprising the above-described electrolyte membrane and an electrode catalyst layer provided on both surfaces of the electrolyte membrane.

In the membrane-electrode assembly, the electrolyte membrane is replaced with the above-mentioned contents.

The electrode catalyst layers provided on both surfaces of the electrolyte membrane include conventional metals known to promote oxidation of hydrogen and reduction of oxygen. As a non-limiting example, the electrode catalyst layer may comprise platinum group metals (platinum, palladium, rhodium, ruthenium, iridium, and osmium), gold, silver, or alloys thereof; An alloy of the above metals with a base metal (gallium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, etc.) may be included. The metal may be used in a non-supported state. The metal may be used in a state of being supported on an inorganic carrier such as acetylene black, a carbon-based carrier such as graphite, alumina or silica. When the metal is used in a supported state, the carrier preferably has a specific surface area of 150 m < 2 > / g or 500-1200 m < 2 > / g and an average of 10-300 nm or 20-100 nm It is preferable to have a particle size.

The membrane-electrode assembly includes a gas diffusion layer adjacent to the electrode catalyst layer. The gas diffusion layer plays a role of supporting the electrode catalyst layer and diffusing the reaction gas into the electrode catalyst layer to improve reaction efficiency. As such a gas diffusion layer, a conventional one such as a carbon paper or a carbon cloth may be used, and preferably a carbon paper or carbon cloth treated with a fluorine resin such as polytetrafluoroethylene may be used. The water repellent gas diffusion layer can prevent the performance of the gas diffusion layer from being deteriorated by water generated when the fuel cell is driven. Further, a microporous layer may be additionally provided between the electrode catalyst layer and the gas diffusion layer to further increase the diffusion effect of the gas.

Meanwhile, the catalyst electrode layer may be prepared by mixing the metal, the binder and the solvent to prepare a catalyst slurry, and applying the catalyst slurry to the gas diffusion layer.

Then, the above-described electrolyte membrane is inserted between the prepared catalyst electrode layers (anode and cathode), and pressed by a roll press or a hot press method to obtain a membrane-electrode assembly. At this time, the roll press compression method may be performed at a pressure of 0 to 2000 psi, a temperature of 50 to 300 ° C, and a moving speed of 0.1 to 3 m / min. The hot pressing may be performed at a pressure of 500 to 2000 psi, a temperature of 50 to 300 DEG C, and a pressure time of 1 to 60 minutes.

According to another embodiment of the present invention, there is provided a fuel cell including the membrane-electrode assembly.

A separator plate is added to the membrane-electrode assembly to obtain a power generation portion. The separator plate is attached to both sides of the membrane-electrode assembly, the separator plate attached to the anode is referred to as an anode separator plate, and the separator plate attached to the cathode is referred to as a cathode separator plate. The anode separator has a flow path for supplying fuel to the anode, and serves as an electron conductor for transferring electrons generated in the anode to an external circuit or an adjacent unit cell. The cathode separation plate has a flow path for supplying an oxidant to the cathode and serves as an electron conductor for transferring electrons supplied from an external circuit or an adjacent unit cell to the cathode. The fuel cell is obtained by selectively adding at least one reformer, a fuel tank, and a fuel pump to the power generation unit.

The fuel cell may be a direct methanol fuel cell. The configuration, output, etc. of the fuel cell can be appropriately designed according to its use.

The electrolyte membrane for a fuel cell provided with the present invention can provide a fuel cell exhibiting improved durability and stable performance by providing a radical scavenger layer containing a plurality of metal oxide nanosheets.

1 is a schematic view showing the structure of an electrolyte membrane according to Examples and Comparative Examples of the present invention.
2 is an atomic force microscopy image of a metal oxide nanosheet synthesized according to an embodiment of the present invention.
3 is a Scanning Electron Microscopy image of a metal oxide nanosheet synthesized according to an embodiment of the present invention.
FIG. 4 is a graph showing changes in voltage versus time with repetitive drying / humidification of a membrane-electrode assembly according to an embodiment and a comparative example of the present invention.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments are described to facilitate understanding of the present invention. However, the following examples are intended to illustrate the present invention without limiting it thereto.

Example  One

(Preparation of composition for forming radical scavenger layer)

1 g of K _x MnO ₄ was reacted with 1 M HCl to exchange K ⁺ ions with H ⁺ ions to obtain H _x MnO ₄ . The resulting H _x MnO ₄ was reacted with tetramethylammonium hydroxide (TMAOH) to prepare a solution in which the manganese oxide nanosheets were dispersed.

0.4 g (10% dispersion aqueous solution) of an ionomer solution (Aquivion 占 ionomer dispersion) was added to 0.45 g of the above manganese oxide nanosheet-containing solution, followed by ultrasonic vibration stirring to obtain a radical trapping layer containing manganese oxide nanosheets Were prepared.

(Preparation of ionomer solution)

Separately from the above composition, distilled water, isopropyl alcohol and 1-propyl alcohol (1: 6: 3, v / v / v) were added to 10 g (10% dispersion water) ionomer solution (Aquivion® ionomer dispersion) Vibration stirring was performed to prepare an ionomer solution.

(Formation of coating layer and drying)

After fixing the fluorine-based reinforcing membrane (Aquivion® membrane) on a dry plate at 60 ° C., the composition for forming a radical scavenger layer was sprayed by compression spraying on the fluorine-based reinforcement film in the X axis and Y axis to form a coating layer. Then, a coating layer of the ionomer solution was formed on the coating layer in the same manner.

The fluorine-based reinforcing film having the coating layers formed thereon was heat-treated in an oven at 80 ° C. for 12 hours, and further heat-treated in an oven at 180 ° C. to form a radical scavenger layer (average thickness of about 500 nm) And an ionomer layer (average thickness of about 500 nm) were successively formed.

(Preparation of membrane-electrode assembly)

Two sheets of the electrode catalyst layer-coated film were cut at 25 cm < 2 >, and the electrolyte membrane was inserted therebetween, followed by thermocompression bonding using a roll press. A sub gasket of 25 ㎠ in size was superimposed thereon, and then a membrane - electrode assembly was manufactured by thermocompression using a roll press.

Comparative Example  One

(Preparation of membrane-electrode assembly)

The film coated with the electrode catalyst layer was cut into two pieces at 25 cm 2, and then a fluorinated reinforcing membrane (Aquivion® membrane) having no radical scavenger layer formed therebetween was inserted and thermocompression bonded using a roll press. A sub gasket of 25 ㎠ in size was superimposed thereon, and then a membrane - electrode assembly was manufactured by thermocompression using a roll press.

Comparative Example  2

(Preparation of composition for forming radical scavenger layer)

0.4 g (10% dispersion aqueous solution) of an ionomer solution (Aquivion 占 ionomer dispersion) was added to 1 g of the K _x MnO ₄ -containing solution, followed by ultrasonic vibration stirring to prepare a composition for forming a radical scavenger layer in the form of particles .

(Preparation of ionomer solution)

Separately from the above composition, distilled water, isopropyl alcohol and 1-propyl alcohol (1: 6: 3, v / v / v) were added to 10 g (10% dispersion water) ionomer solution (Aquivion® ionomer dispersion) Vibration stirring was performed to prepare an ionomer solution.

(Formation of coating layer and drying)

After fixing the fluorine-based reinforcing membrane (Aquivion® membrane) on a dry plate at 60 ° C., the composition for forming a radical scavenger layer was sprayed by compression spraying on the fluorine-based reinforcement film in the X axis and Y axis to form a coating layer. Then, a coating layer of the ionomer solution was formed on the coating layer in the same manner.

 The fluorine-based reinforcing film having the coating layers formed thereon was heat-treated in an oven at 80 ° C. for 12 hours, and further heat-treated in an oven at 180 ° C. to form a radical scavenger layer (average thickness of about 500 nm) And an ionomer layer (average thickness of about 500 nm) were successively formed.

(Preparation of membrane-electrode assembly)

The membrane coated with the electrode catalyst layer was cut into two pieces at 25 cm 2, and then a fluorine-based reinforcing membrane (Aquivion® membrane) coated with manganese oxide particles was inserted therebetween, and thermocompression was performed using a roll press. A sub gasket of 25 ㎠ in size was superimposed thereon, and then a membrane - electrode assembly was manufactured by thermocompression using a roll press.

Comparative Example  3

(Preparation of membrane-electrode assembly)

A film coated with an electrode catalyst layer was cut into two pieces at 25 cm 2, and then a commercially available fluorinated reinforcing membrane (Aquivion® membrane) impregnated with manganese oxide particles was inserted thereinto and thermocompression was performed using a roll press. A sub gasket of 25 ㎠ in size was superimposed thereon, and then a membrane - electrode assembly was manufactured by thermocompression using a roll press.

Test Example  One

(Observation of metal oxide nanosheet)

Atomic force microscopy images of the manganese oxide nanosheets applied to the radical scavenger layer according to Example 1 are shown in FIG. 2, and Scanning Electron Microscopy images are shown in FIG.

Referring to FIG. 2, it was confirmed that the manganese oxide nanosheet used in the formation of the radical scavenger layer in Example 1 had a two-dimensional sheet shape having a thickness of about 4 nm and a length of about 500 nm. Referring to FIG. 3, it was confirmed that the radical scavenger layer according to Example 1 was formed by stacking manganese oxides in the form of a plurality of sheets having a nanometer scale thickness.

Test Example  2

(Evaluation of durability of battery)

In order to test the performance of the unit cell including the membrane-electrode assembly according to Examples and Comparative Examples, a gas diffusion layer (SGL 10BB, SGL Carbon Group) was disposed adjacent to both sides of the membrane- Respectively.

The cell temperature was maintained at 80 ° C, the relative humidity of the hydrogen and air electrodes was 50%, the difference between the atmospheric pressure and the pressure was 0 psig, and the flow rate was maintained at 0.11 L / min and 0.34 L / Circuit Voltage, OCV) were measured for 300 hours in real time. The current-voltage was evaluated at intervals of 100 hours, and the OCV and the performance reduction rate were confirmed. The results are shown in Table 1 and FIG.

Initial IV
OCV (V) Initial IV
Performance (mA / cm2) IV OCV
Reduction rate (uV / h) Performance reduction rate
(uV / h @ 1.2A / cm2) Example 1 0.978 1210 50 60 Comparative Example 1 0.974 1200 190 310 Comparative Example 2 0.975 1180 140 130 Comparative Example 3 0.970 925 69 81

Referring to Table 1 and FIG. 4, it was confirmed that the membrane-electrode assembly according to Example 1 has improved intrinsic radical resistance as compared with Comparative Examples, and OCV can be stably maintained for a longer time in a drying / humidifying environment .

100: electrolyte membrane
10: Radical capturing agent layer
20: ion conductive membrane
1: metal oxide particles
2: metal oxide nanosheet
R: radical

Claims (15)

Ion conductive membrane; And
A radical trapping layer containing a plurality of metal oxide nanosheets laminated on at least one surface of the ion conductive membrane
And an electrolyte membrane for a fuel cell.
The method according to claim 1,
Wherein the radical scavenger layer has an average thickness of 5 to 1000 nm.
The method according to claim 1,
Wherein the metal oxide is selected from the group consisting of silicon oxide, titanium oxide, aluminum oxide, manganese oxide, cerium oxide, iridium oxide, beryllium oxide, zirconium oxide, beryllium oxide, bismuth oxide, gallium oxide, germanium oxide, tantalum oxide, At least one compound selected from the group consisting of vanadium, lanthanum oxide, and the like.
The method according to claim 1,
The radical scavenger layer may be at least one selected from the group consisting of a perfluoro proton conducting polymer, a sulfonated polysulfone copolymer, a sulfonated poly (ether-ketone) based polymer, a sulfonated polyether ether ketone based polymer, a polyimide based polymer 1. An electrolyte membrane for a fuel cell, further comprising at least one ionomer selected from the group consisting of a polymer, a polystyrene-based polymer, a polysulfone-based polymer, and a clay-sulfonated polysulfone nanocomposite.
5. The method of claim 4,
Wherein the ionomer is contained in an amount of 0.1 to 100 parts by weight based on 100 parts by weight of the metal oxide nanosheet.
The method according to claim 1,
And an ionomer layer formed on the radical scavenger layer.
The method according to claim 6,
Wherein the ionomer layer has an average thickness of 100 to 2000 nm.
The method according to claim 1,
The ion conductive membrane may be formed of at least one selected from the group consisting of perfluoro sulfonic acid group-containing polymers, perfluoro proton conductive polymers, sulfonated polysulfone copolymers, sulfonated poly (ether-ketone) polymers, sulfonated polyether ether ketone polymers, , A polystyrene-based polymer, a polysulfone-based polymer, and a clay-sulfonated polysulfone nanocomposite.
Preparing a composition for forming a radical scavenger layer including a metal oxide nanosheet;
Forming a coating layer of the composition for forming a radical scavenger layer on at least one side of the ion conductive membrane; And
And drying the coating layer to form a radical scavenger layer containing a plurality of metal oxide nanosheets
Wherein the electrolyte membrane is made of a metal.
10. The method of claim 9,
The metal oxide nanosheet is formed by a method of reacting a metal oxide with an additive,
The additive is selected from the group consisting of tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPAOH), and tetrabutylammonium hydroxide (TBAOH) Wherein the compound is the above compound.
10. The method of claim 9,
Wherein the composition for forming a radical scavenger layer further comprises an ionomer.
10. The method of claim 9,
Further comprising the step of forming a coating layer of the ionomer solution on the coating layer of the composition for forming a radical scavenger layer.
10. The method of claim 9,
Wherein the drying is performed in a first heat treatment step performed at 20 to 100 ° C for 1 to 24 hours and a second heat treatment step is performed at 120 to 250 ° C for 0.5 to 10 minutes.
1. A membrane-electrode assembly for a fuel cell, comprising: the electrolyte membrane according to claim 1; and an electrode catalyst layer provided on both surfaces of the electrolyte membrane.
A fuel cell comprising the membrane-electrode assembly according to claim 14.

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