KR20170078272A - Electrode for fuel cell, membrane-electrode assembly and fuel cell using the same - Google Patents

Abstract

The present invention relates to an electrode for a fuel cell having an excellent durability by effectively removing radicals generated when a battery is driven, a membrane-electrode assembly capable of realizing stable performance using the electrode, and a fuel cell.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrode for a fuel cell, a membrane-electrode assembly using the electrode, and a fuel cell.

The present invention relates to an electrode for a fuel cell, a membrane-electrode assembly using the electrode, and a fuel cell. More particularly, the present invention relates to an electrode for a fuel cell having an excellent durability by effectively removing radicals generated when a battery is driven, a membrane-electrode assembly capable of realizing stable performance using the electrode, and a fuel cell.

The polymer electrolyte fuel cell (PEFC) is a fuel cell that uses a polymer membrane with hydrogen ion exchange properties as an electrolyte. The polymer electrolyte fuel cell is a solid polymer electrolyte fuel cell (SPEFC), a hydrogen ion exchange membrane fuel cell proton exchange membrane fuel cells, and PEMFC). Polymer electrolyte membrane fuel cells (PEMFCs) have a low operating temperature of 80 ° C, high efficiency, high current density and power density, short startup time and fast response to load changes compared to other types of fuel cells. have. Particularly, since the polymer membrane is used as the electrolyte, it does not need to be controlled for corrosion and electrolyte and is less sensitive to changes in the pressure of the reaction gas. In addition, because of its simple design, easy fabrication, and the ability to produce a wide range of output power, PEFC can be used in a wide variety of applications, including power sources for non polluting vehicles, locally installed power generation, mobile power, and military power. There is an advantage that can be.

The characteristics of a proton exchange membrane in a polymer electrolyte fuel cell (PEFC) are mainly expressed by an ion exchange capacity (IEC) or equivalent weight (EW), and a proton exchange membrane used as an electrolyte membrane for a fuel cell The properties that should have are high hydrogen ion conductivity and mechanical strength, low gas permeability and water transfer. During dehydration, the hydrogen ion conductivity drops sharply and must be resistant to dehydration. Resistance to oxidation and reduction reactions, hydrolysis, etc. directly encountered by the electrolyte membrane must be high, the cation binding force must be good, and homogeneity is required. These properties must be maintained for a certain period of time. In addition to satisfying all of these conditions, it is necessary to develop inexpensive and environmentally friendly manufacturing technology in order to link it with commercialization.

The types of polymer electrolyte membrane can be classified into perfluorocarbon, partial fluorocarbon, and hydrocarbon. The perfluorinated electrolyte membranes were commercialized as Nafion® from Dufont, Aciplex® from Asahi Chemical, and Flemion® from Asahi Glass, which meet the requirements of hydrogen ion exchange membranes such as high mechanical strength, physical and chemical stability, and high cation conductivity, but hydrogen ion permeability And the physical and chemical stability decreases during long-term operation, and cell performance is deteriorated. Meanwhile, in the fluorine-based and hydrocarbon-based electrolyte membranes, a radical scavenger such as CeO ₂ is impregnated with a porous support together with an electrolyte membrane in order to suppress the electrolyte membrane due to radicals generated during the operation of the fuel cell, Thereby improving the radical resistance.

However, in the case of the conventional technique, when the catalyst of the radical protection layer on the surface of the electrolyte membrane is in electrical contact with the electrode layer, there is a limit in that the radical removal effect is reduced and the permeability is increased to deteriorate the MEA performance.

Accordingly, it is required to develop a polymer electrolyte fuel cell electrode capable of achieving stable performance when applied to a battery while maximizing the radical scavenging effect.

The present invention provides an electrode for a fuel cell having excellent durability by effectively removing radicals generated when a battery is driven.

In addition, the present invention provides a membrane-electrode assembly and a fuel cell capable of realizing stable performance by using the electrode.

In the present specification, an electrode catalyst layer; An insulating layer formed on at least one surface of the electrode catalyst layer and including an ion conductive polymer; And a radical protection layer formed on the insulating layer and including at least one or more metal and ion conductive polymer, wherein the metal included in the radical protection layer is dispersed in a state in which the ion conductive polymer is in contact with the surface, An electrode is provided.

In this specification, there is also provided a membrane-electrode assembly for a fuel cell comprising an electrolyte membrane and two electrodes provided on both sides of the electrolyte membrane, wherein at least one of the two electrodes includes the electrode for a fuel cell.

In this specification, a fuel cell including the membrane-electrode assembly is also provided.

Hereinafter, an electrode for a fuel cell according to a specific embodiment of the present invention, a membrane-electrode assembly using the same, and a fuel cell will be described in detail.

According to an embodiment of the present invention, an electrode catalyst layer; An insulating layer formed on at least one surface of the electrode catalyst layer and including an ion conductive polymer; And a radical protection layer formed on the insulating layer and including at least one or more metal and ion conductive polymer, wherein the metal included in the radical protection layer is dispersed in a state in which the ion conductive polymer is in contact with the surface, An electrode may be provided.

The present inventors have further found that by using the above-described specific electrode for a fuel cell, by further introducing an insulating layer including an ion conductive polymer together with a radical protective layer, the radical protective layer and the electrode catalyst layer can be separated from each other, It was confirmed that the electrical contact of the catalyst can be blocked. Accordingly, it has been confirmed through experiments that the electrode structure having excellent physical / chemical durability can be formed by maximizing the radical removal effect by the radical protection layer, and the invention is completed.

Particularly, since the insulation of the radical protection layer can be ensured by a separate insulation layer, there is no need to use a separate carbon support as in the prior art, so that the ion conductive polymer is in direct contact with the metal surface in the radical protection layer State, and the radical removal efficiency can be maximized.

In addition, since the insulating layer includes the ion conductive polymer, not only the electrical contact between the electrode catalyst layer and the catalyst of the radical protecting layer is blocked, but also when applied to a fuel cell and driven, Performance can be realized.

The electrode for a fuel cell of the above-described embodiment can be used for all energy storage and production devices such as a solar cell, a secondary battery, a supercapacitor, and the like. It can also be used for an organic electroluminescent device.

Specifically, the electrode for a fuel cell of one embodiment will be described as follows.

The electrode catalyst layer

The electrode catalyst layer may comprise conventional metals known to catalyze the oxidation of hydrogen and the reduction of oxygen. For example, the electrode catalyst layer may include a platinum group metal (platinum, palladium, rhodium, ruthenium, iridium, and osmium), gold, silver, Vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, and the like).

The metal may be used in a non-supported state or in a supported state. When the metal is in a supported state, it may be supported on an inorganic carrier such as acetylene black, carbon-based support 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 more, 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.

Examples of the method for producing the electrode catalyst layer are not limited to a wide range. For example, the method can be manufactured by mixing the metal, the binder and the solvent to prepare a catalyst slurry, and applying the catalyst slurry.

Insulating layer

The insulating layer included in the electrode for a fuel cell may be formed on at least one surface of the electrode catalyst layer and may include an ion conductive polymer.

The insulating layer may be formed on at least one surface of the electrode catalyst layer and may be stacked for the purpose of separating the electrode protection layer from the electrode protection layer.

At least one surface of the electrode catalyst layer in which the insulating layer is formed means one surface of the upper surface or the lower surface of the electrode catalyst layer or may include both the upper surface and the lower surface. Specifically, referring to FIG. 1, an insulating layer 4 may be formed on the upper surface of the electrode catalyst layer 5, for example.

The insulating layer may include an ion conductive polymer. The ion conductive polymer means a polymer having charge transport properties by ions, and the ion conductive polymer may include a fluorinated polymer or a hydrocarbon polymer.

The specific examples of the fluorine-based polymer are not particularly limited, and for example, a perfluoro sulfonic acid group-containing polymer or a perfluoro-type proton conductive polymer can be used.

Although specific examples of the hydrocarbon-based polymer are not limited, examples thereof include sulfonated polysulfone copolymers, sulfonated poly (ether-ketone) based polymers, sulfonated polyether ether ketone based polymers, polyimide based polymers , A polystyrene-based polymer, a polysulfone-based polymer, a clay-sulfonated polysulfone nanocomposite, or a mixture of two or more thereof.

The amount of the ion conductive polymer contained in the insulating layer may be 300 to 500 parts by weight or 350 to 400 parts by weight based on 100 parts by weight of the ion conductive polymer contained in the radical protection layer.

The thickness of the insulating layer may be 10 nm to 2000 nm, or 50 nm to 1500 nm. If the thickness of the insulating layer is too thick to be more than 2000 nm, the performance of the membrane-electrode assembly may deteriorate, and it may become difficult to manufacture a thin electrode having a small thickness.

More specifically, the ratio of the thickness of the radical protective layer to the thickness of the insulating layer may be 1 to 10, or 1.1 to 5, or 1.2 to 3. The ratio of the thickness of the radical protection layer to the thickness of the insulation layer means a value obtained by dividing the thickness of the radical protection layer by the thickness of the insulation layer.

Radical protection layer

The radical protection layer included in the electrode for a fuel cell may be formed on the insulating layer and may include at least one metal and an ion conductive polymer.

Specifically, the radical protection layer may be formed on the other surface of the insulating layer not in contact with the electrode catalyst layer. That is, an electrode catalyst layer may be formed on one side of the insulating layer, and a radical protection layer may be formed on the other side of the insulating layer.

More specifically, the electrode having the above-described radical protection layer may have a three-layer structure in which the electrode catalyst layer 5, the insulating layer 4, and the radical protection layer 3 are stacked in this order as shown in FIG.

The radical protection layer may include at least one metal in order to effectively remove radicals generated during operation of the fuel cell. The at least one metal may catalyze the oxidation of hydrogen and the reduction of oxygen, and may decompose the peroxy radical and the hydroperoxy radical into water and oxygen to remove radicals.

The at least one metal may include at least one metal selected from the group consisting of metal elements belonging to group 3 to group 13 of the periodic table. That is, the metal may include a transition metal belonging to Group 3 to 12 of the periodic table or a post-transition metal belonging to Group 13 of Periodic Table.

More specifically, the at least one metal may include an alloy including palladium (Pd) or palladium. The alloy containing palladium may include at least one metal selected from the group consisting of palladium and metal elements belonging to Group 3 to Group 13 of the periodic table.

Since the palladium metal has a higher hydrogen bonding energy than other metals, it can exhibit better selectivity for radicals or ions. Accordingly, when palladium metal is used for the radical protection layer, generation of hydrogen peroxide and radicals generated during the operation of the fuel cell is suppressed. The effect of removing generated radicals can be maximized, thereby improving gas permeability and endurance performance of the electrode.

Examples of the metal added to the palladium-containing alloy other than palladium include, but are not limited to, platinum (Pt), gold (Au), silver (Ag), gallium (Ga), titanium (V), Cr, Mn, Fe, Co, Ni, Cu, The above mixture may be used. More specifically, examples of the alloy containing palladium include a palladium-cobalt alloy, a palladium-titanium alloy, a palladium-manganese alloy, a palladium-platinum alloy, a palladium-nickel alloy or a mixture thereof.

The radical protection layer may include an ion conductive polymer. The ion conductive polymer may serve as a binder to stably stack the radical protection layer including the metal. Accordingly, at least one kind of metal may be dispersed in the ion conductive polymer in the radical protection layer.

Specifically, the metal may be dispersed while the ion conductive polymer is in contact with the surface. This is because the metal is used directly without being supported on a carrier such as a carbon support or the like. As the metal is directly used without being supported on the support, the active surface area of the metal increases, and the radical removal efficiency by the radical protection layer can be maximized.

More specifically, 50% or more, or 50% to 100% of the total surface area of the metal contained in the radical protection layer may be in contact with the ion conductive polymer. On the surface of the metal contacting the ion conductive polymer, hydrogen peroxide and radical scavenging activity by the metal may be exhibited. Thus, when more than 50% of the total surface area of the metal is in contact with the ion conductive polymer, the active surface area of the metal may increase to more than 50% of the total surface area.

On the other hand, when less than 50% of the total surface area of the metal is in contact with the ion conductive polymer as in the prior art in which the metal is supported on the carrier, the active surface area of the metal is reduced to less than 50% There is a limit in that the removal efficiency of hydrogen peroxide and radicals is reduced.

The ion conductive polymer means a polymer having charge transport properties by ions, and the ion conductive polymer may include a fluorinated polymer or a hydrocarbon polymer.

The specific examples of the fluorine-based polymer are not particularly limited, and for example, a perfluoro sulfonic acid group-containing polymer or a perfluoro-type proton conductive polymer can be used.

Although specific examples of the hydrocarbon-based polymer are not limited, examples thereof include sulfonated polysulfone copolymers, sulfonated poly (ether-ketone) based polymers, sulfonated polyether ether ketone based polymers, polyimide based polymers , A polystyrene-based polymer, a polysulfone-based polymer, a clay-sulfonated polysulfone nanocomposite, or a mixture of two or more thereof.

The ion conductive polymer contained in the radical protection layer and the ion conductive polymer included in the insulation layer may be the same material or different materials.

The radical protection layer may contain at least one metal from 1 to 20 parts by weight, or from 3 to 10 parts by weight, or from 5 to 10 parts by weight, or from 5.5 to 10 parts by weight, based on 100 parts by weight of the ion conductive polymer. May be included in parts by weight. When too much metal is added to the ion conductive polymer in the radical protection layer, the stability and uniformity of the coating composition for forming the radical protection layer may be decreased, and the coating property may be deteriorated.

The thickness of the radical protection layer may be 10 nm to 2000 nm, or 50 nm to 1500 nm. If the thickness of the radical protective layer is too thick to be more than 2000 nm, the performance of the membrane-electrode assembly may deteriorate, and it may become difficult to produce a thin electrode having a small thickness.

Method for manufacturing electrode for fuel cell

The method for manufacturing an electrode for a fuel cell includes the steps of forming an insulating layer by coating a first coating composition containing an ion conductive polymer on at least one surface of an electrode catalyst layer; And coating a second coating composition containing at least one or more metal and ion conductive polymers on the insulating layer to form a radical protective layer.

In the step of coating the first coating composition containing the ion conductive polymer on at least one surface of the electrode catalyst layer to form an insulating layer, the first coating composition may include an ion conductive polymer as a composition for forming an insulating layer .

The first coating composition may further comprise a solvent. The solvent may include an aqueous solvent or an organic solvent, and a commonly used aqueous or organic solvent may be used without limitation. Specifically, the same solvent as that used in the preparation of the electrolyte membrane described later may be used.

Examples of the method for producing the first coating composition are not limited to a specific method. For example, a method of dispersing the ion conductive polymer in an organic solvent or an aqueous solvent may be used.

Examples of the method of coating the first coating composition are also not limited to a specific one, and examples thereof include coating methods such as spraying, screen printing, inkjet printing, dipping, bar coating, cap coating, knife coating, slot die coating, ≪ / RTI >

The method may further include drying the coated insulating layer after coating the first coating composition containing the ion conductive polymer on at least one surface of the electrode catalyst layer to form an insulating layer. The coating layer of the first coating composition and the coating layer of the second coating composition may be sequentially formed on the electrode catalyst layer, and then the coating layers may be dried together. Alternatively, the coating layer may be formed and dried separately.

For example, the first heat treatment step is performed at 20 to 100 ° C. for 1 to 24 hours, and the second heat treatment step is 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 the insulating layer can be stacked more stably on the electrode catalyst layer. In addition, when the ion conductive polymer is used, sufficient heat curing can be achieved through the plurality of heat treatment processes.

The second coating composition may further include a solvent in the step of forming a radical protection layer by coating a second coating composition containing at least one metal and an ion conductive polymer on the insulating layer. The metal, the ion conductive polymer, the electrode catalyst layer, and the radical protection layer may include the above-described contents in the embodiment.

The solvent may include an aqueous solvent or an organic solvent, and a commonly used aqueous or organic solvent may be used without limitation. Specifically, the same solvent as that used in the preparation of the electrolyte membrane described later may be used.

The method for preparing the second coating composition is not limited to a specific example. For example, a method of dispersing the at least one metal or ion conductive polymer in an organic solvent or an aqueous solvent may be used.

Examples of the method of coating the second coating composition are also not limited to a specific one and may be applied by any method such as spraying, screen printing, inkjet printing, dipping, bar coating, cap coating, knife coating, slot die coating, gravure coating, ≪ / RTI >

The step of coating the second coating composition containing the at least one metal and the ion conductive polymer on the insulating layer to form the radical protection layer may further include drying the coated radical protection layer. The coating layer of the first coating composition and the coating layer of the second coating composition may be sequentially formed on the electrode catalyst layer, and then the coating layers may be dried together. Alternatively, the coating layer may be formed and dried separately.

For example, the first heat treatment step is performed at 20 to 100 ° C. for 1 to 24 hours, and the second heat treatment step is 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 the radical protection layer can be stacked more stably. In addition, when the ion conductive polymer is used, sufficient heat curing can be achieved through the plurality of heat treatment processes.

According to another embodiment of the present invention, there is provided a fuel cell membrane-electrode assembly including an electrolyte membrane and two electrodes provided on both surfaces of the electrolyte membrane, wherein at least one of the two electrodes is a membrane- An electrode junction body may be provided.

The electrolyte membrane is a polymer membrane having electrical insulation and ionic conductivity, and may include an ion conductive polymer. The ion conductive polymer means a polymer having charge transport properties by ions, and the ion conductive polymer may include a fluorinated polymer or a hydrocarbon polymer.

The specific examples of the fluorine-based polymer are not particularly limited, and for example, a perfluoro sulfonic acid group-containing polymer or a perfluoro-type proton conductive polymer can be used.

Although specific examples of the hydrocarbon-based polymer are not limited, examples thereof include sulfonated polysulfone copolymers, sulfonated poly (ether-ketone) based polymers, sulfonated polyether ether ketone based polymers, polyimide based polymers , A polystyrene-based polymer, a polysulfone-based polymer, a clay-sulfonated polysulfone nanocomposite, or a mixture of two or more thereof.

The ion conductive polymer contained in the electrolyte membrane and the ion conductive polymer included in the radical protective layer or the insulating layer of the embodiment may be the same material or different materials.

A more specific example is a fluorine-based reinforcing membrane (Aquivion® membrane).

Two electrodes may be provided on both sides of the electrolyte membrane. The two electrodes (anode and cathode) are formed on both surfaces of the electrolyte membrane, respectively, and can serve as a hydrogen electrode or an air electrode. At least one of the two electrodes may include the electrode for a fuel cell of the embodiment. That is, only one of the two electrodes may be the fuel cell electrode of the embodiment, or both electrodes may be the electrode of the fuel cell of the embodiment.

Specifically, when the electrode for a fuel cell according to one embodiment is used, as shown in FIG. 2, it is preferable that an insulating layer and a radical protection layer are positioned between the electrode catalyst layer and the electrolyte membrane.

The membrane-electrode assembly may further include a gas diffusion layer. The gas diffusion layer serves to support the electrode catalyst layer included in the electrode and diffuses the reaction gas into the electrode catalyst layer to improve the reaction efficiency. Examples of the gas diffusion layer include carbon paper or carbon cloth. Preferably, carbon paper or carbon cloth is treated with a fluorine resin such as polytetrafluoroethylene. 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. The microporous layer may be prepared by applying a composition containing a conductive material such as carbon powder, carbon black, activated carbon, and acetylene black, a binder such as polytetrafluoroethylene, and an ion conductive polymer.

In addition, the membrane-electrode assembly may further include a sub gasket. The sub gasket serves to protect the electrodes and the electrolyte membrane and to ensure easiness in handling when assembling the fuel cell, and may be bonded to both edge regions of the electrode or the electrolyte membrane. A specific example of the sub gasket is not limited to a specific one. For example, a polymer film such as polyethylene (PE) or polyethylene naphthalate (PEN) can be used.

On the other hand, an example of a method for producing the membrane-electrode assembly is not limited to a specific one. For example, a method of inserting an electrolyte membrane between two electrodes (an anode and a cathode) and pressing them by a roll press or a hot- have. 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 for a fuel cell of another embodiment.

Specifically, the fuel cell may include a membrane-electrode junction body for a fuel cell. The number of the membrane-electrode assemblies is not limited and may include a single membrane or a plurality of membrane-electrode assemblies.

In addition, the fuel cell may include a power generation unit having a separator on both sides of the membrane-electrode assembly. 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 may further include at least one selected from the group consisting of a reformer, a fuel tank, and a fuel pump. The reformer, the fuel tank, and the fuel pump can be used without limitation as is well known in the fuel cell field.

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. Specifically, the use of the fuel cell may be, for example, a vehicle fuel cell. The vehicle may include vehicles for all purposes, such as vehicles for transporting vehicles, trucks, vehicles for other purposes such as excavators, forklifts, and the like. More specifically, it can be used in a fuel cell system in an environment in which repeated currents are required to be changed in a short period of time, such as on / off of a vehicle or sudden emergence.

According to the present invention, it is possible to provide an electrode for a fuel cell having excellent durability by effectively removing radicals generated when a battery is driven, a membrane-electrode assembly capable of realizing stable performance using the electrode, and a fuel cell.

Fig. 1 schematically shows the structure of the electrode for a fuel cell manufactured in Example 1. Fig.
2 schematically shows the structure of a membrane-electrode assembly for a fuel cell manufactured in Example 1. [

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

≪ Example: Preparation of membrane-electrode composite >

Example 1

a) Preparation of radical protective layer coating solution

After adding distilled water, isopropyl alcohol and 1-propyl alcohol in a volume ratio of 1: 1: 1 to a 3.25 g (5% dispersion aqueous solution) ionomer (Aquivion® ionomer dispersion D83-24B) solution containing 0.195 g of palladium black Followed by ultrasonic vibration stirring to prepare a radical protective layer coating solution.

b) Preparation of insulating layer coating solution

Isopropyl alcohol and 1-propyl alcohol were added in a volume ratio of 1: 1: 1 to an ionomer (Aquivion (R) ionomer dispersion D83-24B) solution of 12.6 g (24% dispersion aqueous solution) Ionomer coating solution was prepared.

c) Preparation of radical protective layer and insulating layer

The electrodes were fixed on a dry plate at 60 DEG C, and then the insulating layer coating solution was sprayed on the electrodes using compression spray to coat the insulating layer.

The radical protective layer coating solution was sprayed onto the insulating layer using a compression spray to prepare a radical protective layer. Thereafter, the substrate was dried in an oven at 80 ° C. for 12 hours, and then heat treated in an oven at 180 ° C. to obtain an electrode coated with an insulating layer having a thickness of 800 nm and a protective layer having a thickness of 1000 nm.

d) Preparation of membrane-electrode complex

A fluorine-based reinforcing membrane (Aquivion® membrane) was inserted between the electrode coated with the radical protection layer and the insulating layer and the other electrode, followed by thermocompression using a roll press. At this time, the fluorine-based reinforcing membrane was inserted between the radical protection layer of the electrode coated with the radical protection layer and the insulation layer and the other electrode. A sub - gasket of 25 ㎠ in size was superimposed thereon, and then a membrane - electrode composite was manufactured by thermocompression using a roll press.

≪ Comparative Example: Preparation of membrane-electrode composite >

Comparative Example 1

A membrane-electrode composite was prepared in the same manner as in Example 1, except that an electrode on which a radical protection layer and an insulating layer were not formed was used.

Comparative Example 2

A membrane-electrode composite was prepared in the same manner as in Example 1, except that an electrode in which only a radical protective layer was formed and an insulating layer was not formed was used.

<Experimental Example: Measurement of Performance of the Membrane-Electrode Composite Obtained in Examples and Comparative Examples>

Experimental Example 1: Evaluation of durability of battery

In order to test the performance of the unit cell including the membrane-electrode composite obtained in 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. Then, after the activation was carried out for three hours at a cell temperature of 65 ° C and a relative humidity of 100% at an interval of 150 hours, the current-voltage was evaluated to determine the OCV and the performance reduction rate. The results are shown in Table 1 below.

Evaluation results of durability of a battery using the membrane-electrode composite of Examples and Comparative Examples division The 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 1.005 1210 41 53 Comparative Example 1 0.975 1250 143 187 Comparative Example 2 0.993 1200 95 100

As shown in Table 1, the OCV reduction rate in Example 1 in which both the radical protection layer and the insulating layer were secured was 41 uV / h, and 143 uV / h in Comparative Example 1 in which both the radical protection layer and the insulating layer were not secured And 95 V / h of Comparative Example 2 in which only the radical protective layer was secured.

The membrane-electrode composite with the insulating layer secured can prevent the electrode and the catalyst of the protective layer from electrical contact when compared with a membrane-electrode composite in which the insulating layer is not present, thereby maximizing the radical removal effect and improving the OCV durability .

In Table 1, the performance reduction ratio of Example 1 in which both the radical protective layer and the insulating layer were secured was 53 uV / h @ 1.2 A / cm 2, 187 uV / h @ 1.2 A / cm &lt; 2 &gt; and 100 uV / h @ 1.2 A / cm &lt; 2 &gt; of Comparative Example 2 in which only the radical protection layer is secured.

 In the membrane-electrode composite of Comparative Example 1 in which no radical protection layer was present, it was confirmed that the OCV performance reduction rate was greatly increased due to the increase of the resistance of the membrane-electrode composite by the radical in the performance test.

Accordingly, the membrane-electrode composite in which both the radical protection layer and the insulation layer are secured in the drying / humidifying environment has increased physical and chemical resistance of the electrode compared to the conventional membrane-electrode composite, thereby improving OCV performance and durability .

1 - electrode catalyst layer
2-ion conductive membrane
3-radical protection layer
4 - insulating layer
5-electrode catalyst layer

Claims (12)

An electrode catalyst layer;
An insulating layer formed on at least one surface of the electrode catalyst layer and including an ion conductive polymer; And
And a radical protection layer formed on the insulating layer and including at least one or more metal and ion conductive polymer,
Wherein the metal contained in the radical protection layer is dispersed while the ion conductive polymer is in contact with the surface of the electrode.
The method according to claim 1,
Wherein at least 50% of the total surface area of the metal contained in the radical protection layer is in contact with the ion conductive polymer.
The method according to claim 1,
Wherein the radical protective layer comprises at least one metal in an amount of 1 part by weight to 20 parts by weight based on 100 parts by weight of the ion conductive polymer.
The method according to claim 1,
Wherein the at least one metal comprises at least one metal selected from the group consisting of metal elements belonging to groups 3 to 13 of the periodic table.
The method according to claim 1,
Wherein the at least one metal comprises an alloy including palladium or palladium.
6. The method of claim 5,
Wherein the alloy containing palladium comprises at least one metal selected from the group consisting of palladium and metal elements belonging to groups 3 to 13 of the periodic table.
The method according to claim 1,
Wherein the insulating layer has a thickness of 10 nm to 2000 nm.
The method according to claim 1,
And the thickness of the radical protection layer is 10 nm to 2000 nm.
The method according to claim 1,
Wherein the ratio of the thickness of the radical protective layer to the thickness of the insulating layer is 1 to 10. [
The method according to claim 1,
Wherein the ion conductive polymer contained in the insulating layer comprises a fluorine-based polymer or a hydrocarbon-based polymer.
An electrolyte membrane, and two electrodes provided on both surfaces of the electrolyte membrane,
Wherein at least one of the two electrodes comprises the electrode for a fuel cell according to claim 1.
12. A fuel cell comprising the membrane-electrode junction body for a fuel cell according to claim 11.

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