KR20220103414A - Anode electrode for fuel cell and manufacturing method thereof - Google Patents

Abstract

One embodiment of the present invention provides an anode electrode for a fuel cell and a manufacturing method thereof. According to an embodiment of the present invention, provided are an anode electrode for a fuel cell capable of operating with high efficiency even at a high temperature by securing a sufficient amount of phosphoric acid while preventing leakage of phosphoric acid from the electrode by configuring a catalyst layer into double layers using two different types of hydrophobic binders, and a manufacturing method thereof.

Description

Anode electrode for fuel cell and manufacturing method thereof

The present invention relates to an anode electrode for a fuel cell and a method for manufacturing the same, and more particularly, to an anode electrode for a fuel cell, characterized in that it is possible to prevent leakage of phosphoric acid by using two types of hydrophobic binders, and a method for manufacturing the same.

A polymer electrolyte membrane fuel cell is a fuel cell that uses a polymer membrane with hydrogen ion exchange characteristics as an electrolyte. It is called by various names such as membrane fuel cell (PEMFC). The polymer electrolyte membrane fuel cell has the advantages of high efficiency, high current density and power density, simple design, and easy fabrication compared to fuel cells in the form of polymer electrolyte membrane fuel cells. Due to these characteristics, the polymer electrolyte membrane fuel cell can be applied to a wide variety of fields, such as a power source for pollution-free vehicles, locally installed power generation, power source for spacecraft, power source for mobile use, and power source for military use.

The polymer electrolyte membrane fuel cell can be divided into a low-temperature type and a high-temperature type operated at 120°C or higher.

Low-temperature polymer electrolyte membrane fuel cells (LT-PEMFC) can operate at temperatures below 100°C and produce high output, so they can be used for transportation and small-sized power generation. This complex, waste heat has a characteristic that it is difficult to recycle.

On the other hand, the high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) has several advantages over the low-temperature type. For example, the high-temperature type polymer electrolyte fuel cell does not require a humidifier, which is necessary for the low-temperature type, because the proton conduction phenomenon does not depend on water. It has the advantage of easy stack design. In addition, due to the high operating temperature that can be operated from 120 ° C to 180 ° C, catalyst poisoning to carbon monoxide in the reformed gas is small, the electrochemical reaction of the fuel cell can be improved, and the concentration polarization can also be reduced by reducing the mass transfer resistance.

However, since high-temperature polymer electrolyte membrane fuel cells operate at a temperature of 120°C or higher, Nafion cannot be used as an ionomer, so it is mainly used in the form of impregnated phosphoric acid that can move hydrogen ions in the binder. However, the performance and durability are deteriorated due to the phosphoric acid leakage phenomenon in which the impregnated phosphoric acid flows through the electrode and the phosphoric acid poisoning phenomenon covering the catalyst surface in the electrode, which is especially seen in the anode.

Therefore, there was a need for research to solve and improve the phosphoric acid poisoning and phosphoric acid leakage of the anode electrode of the fuel cell.

Republic of Korea Patent Registration No. 10-1101497

The technical problem to be achieved by the present invention is to solve the problems of the prior art described above, and while being able to operate at a high temperature of 120° C. or higher, the electrode, in particular, an anode electrode for a fuel cell capable of improving fuel cell performance by preventing phosphoric acid leakage from the anode and to provide a method for manufacturing the same.

In addition, it is to provide a membrane electrode assembly including the anode for the fuel cell.

In addition, it is to provide a fuel cell including the anode electrode for the fuel cell.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. There will be.

In order to achieve the above technical problem, an embodiment of the present invention provides an anode electrode for a fuel cell.

In one embodiment of the present invention, the anode electrode for the fuel cell, the gas diffusion layer does not include a microporous layer; a first catalyst layer positioned on the gas diffusion layer and including a first binder; and a second catalyst layer positioned on the first catalyst layer and including a second binder, wherein the first binder is PTFE, and the second binder is a different type of hydrophobicity from the PTFE. It may be characterized as a binder.

The gas diffusion layer may be characterized in that it includes any one or more selected from the group consisting of carbon cloth, carbon paper, and carbon felt.

The second binder may be characterized in that it has a relatively lower hydrophobicity than PTFE.

The second binder may be characterized in that it includes any one or more selected from the group consisting of PVDF, PBI, PVA and PAA.

The first catalyst layer and the second catalyst layer are each independently any one or more metals selected from the group consisting of platinum, palladium, cobalt, gold, ruthenium, tin, molybthenium, rhodium, iridium, bismuth, copper, yttrium and chromium. It may be characterized in that it contains a catalyst.

The weight per unit area (M/A) of the metal catalyst with respect to the entire catalyst layer including the first catalyst layer and the second catalyst layer is 0.1 mg/cm ² to 0.5 mg/cm ² It may be characterized by being.

A weight ratio of the metal catalyst supported on the first catalyst layer and the metal catalyst supported on the second catalyst layer may be 1:9 to 6:4.

The first catalyst layer may be formed on the gas diffusion layer through spraying.

In order to achieve the above technical object, another embodiment of the present invention provides a membrane electrode assembly.

In an embodiment of the present invention, the membrane electrode assembly may include the anode electrode for a fuel cell according to an embodiment of the present invention.

In order to achieve the above technical object, another embodiment of the present invention provides a fuel cell.

In an embodiment of the present invention, the fuel cell may include the anode electrode for a fuel cell according to an embodiment of the present invention.

In order to achieve the above technical object, another embodiment of the present invention provides a method of manufacturing an anode electrode for a fuel cell.

In an embodiment of the present invention, the method for manufacturing the anode electrode for a fuel cell includes: preparing a composition for forming a first catalyst layer including a first binder and a metal catalyst; forming a first catalyst layer by applying the composition for forming a first catalyst layer on a gas diffusion layer; preparing a composition for forming a second catalyst layer including a second binder and a metal catalyst; and applying the composition for forming a second catalyst layer on the first catalyst layer to form a second catalyst layer;

The gas diffusion layer is characterized in that it does not include a microporous layer, the first binder is characterized in that it is PTFE, and the second binder is a hydrophobic binder of a different type from the PTFE. can

In the forming of the first catalyst layer, the composition for forming the first catalyst layer is applied on the gas diffusion layer through a spray process to form the first catalyst layer.

According to an embodiment of the present invention, by configuring the catalyst layer as a double layer using two different types of hydrophobic binders, the anode electrode for a fuel cell that can be driven with high efficiency even at high temperatures by securing sufficient phosphoric acid loading while preventing phosphoric acid leakage from the electrode and There is an effect that can provide a manufacturing method thereof.

The effects of the present invention are not limited to the above effects, and it should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a schematic diagram schematically showing an anode electrode for a fuel cell according to an embodiment of the present invention.
2 is a view showing an SEM image of the anode electrode of the membrane electrode assembly manufactured according to the embodiment of the present invention.
3 is a graph showing voltage and power density per current density of membrane electrode assemblies according to Examples and Comparative Examples of the present invention.
4 is a graph showing voltage and peak power density of membrane electrode assemblies according to Examples and Comparative Examples of the present invention.
FIG. 5 is a graph showing voltage changes according to time of membrane electrode assemblies according to Examples and Comparative Examples of the present invention.
6 is a schematic diagram schematically showing a process of obtaining a sample for TGA analysis by cutting the top of the anode electrode for a fuel cell prepared in Example 1 of the present invention.
7 is a graph showing the TGA analysis of each partial sample of the anode electrode for a fuel cell prepared in Example 1 of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in several different forms, and thus is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is "connected (connected, contacted, coupled)" with another part, it is not only "directly connected" but also "indirectly connected" with another member interposed therebetween. "Including cases where In addition, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

An anode electrode for a fuel cell according to an embodiment of the present invention will be described.

1 is a schematic diagram schematically showing an anode electrode for a fuel cell according to an embodiment of the present invention.

Referring to FIG. 1 , an anode electrode for a fuel cell according to an embodiment of the present invention includes: a gas diffusion layer 10 that does not include a microporous layer; a first catalyst layer 20 positioned on the gas diffusion layer and including a first binder; and a second catalyst layer 30 positioned on the first catalyst layer and including a second binder.

In this case, the first binder may be made of polytetrafluoroethylene (PTFE).

The PTFE has a main chain made of carbon, and two fluorine groups (-F) are bonded to all carbons. Due to the fluorine group, there is a strong attractive force between the PTFE molecules, and the tendency to repel other types of molecules approaching the PTFE is evident. Due to this, PTFE is characterized in that it has superhydrophobic properties.

Due to these characteristics, as in the present invention, by forming the first catalyst layer on the gas diffusion layer using PTFE as a binder, phosphoric acid can be prevented from leaking through the electrode due to the superhydrophobic property of PTFE.

In this case, the second binder may be a hydrophobic binder of a different type from the PTFE.

Preferably, the second binder may be a binder having a relatively lower hydrophobicity than PTFE.

More preferably, the second binder comprises at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polybenzimidazole (PBI), polyvinyl alcohol (PVA) and poly (acrylic acid) (PAA). can be done with

Most preferably, the second binder may be PVDF.

As described above, PTFE has superhydrophobic properties due to the property that every carbon in the main chain has two fluorine groups (-F). The use of PTFE as a binder has the effect of preventing phosphoric acid from leaking, but there is also a need for the catalyst layer to support phosphoric acid at a certain level or more in order to improve the efficiency of the fuel cell. However, as described above, when the catalyst layer is composed of only PTFE, the leakage of phosphoric acid can be effectively prevented, but the effect of sufficiently supporting and impregnating the phosphoric acid in the electrode may be reduced.

On the other hand, PVDF has the same main chain as PTFE, but all carbons in PTFE have two fluorine groups, whereas a carbon having two hydrogen groups (-H) and two fluorine groups (-F) By alternately presenting carbons with

Therefore, in the present invention, PVDF having a relatively lower hydrophobicity than PTFE is applied as a second catalyst layer to form the catalyst layer as a double layer. came to configure.

In this case, the gas diffusion layer is characterized in that it comprises any one or more selected from the group consisting of carbon cloth, carbon paper, and carbon felt, microporous layer (micro porous layer). layer, MPL) is not included.

Most preferably, the gas diffusion layer may be made of carbon felt.

A polymer electrolyte membrane fuel cell is generally an electrode divided into an anode and a cathode, and a hydrogen ion conductive polymer electrolyte membrane positioned between the anode and the cathode MEA (membrane electrode assembly) including structure. In this case, the electrodes of the anode and the cathode causing the electrochemical reaction generally include a gas diffusion layer (GDL) and a catalyst layer, respectively.

Here, the gas diffusion layer (GDL) is generally used in a form including a microporous layer (MPL) coated on one surface.

However, since MPL has fine and dense pores, it is a factor that lowers the gas permeability and diffusivity of the entire GDL. For this reason, the electrode using GDL including MPL has a problem in that the concentration of the catalyst layer surface is lowered and the mass-transport loss of the fuel cell is markedly due to this. In addition, MPL, which is currently most used, is vulnerable to cracking due to low mechanical strength and is easily damaged, so there is also a problem of poor usability.

Therefore, in the present invention, the above-mentioned possible problems can be improved by not including the microporous layer in the gas diffusion layer.

In addition, according to the experimental example to be described later, it was confirmed that the fuel cell composed of the gas diffusion layer not including the microporous layer of the present invention has higher performance than the fuel cell composed of the gas diffusion layer including the microporous layer in the related art, When the anode electrode for a fuel cell according to an embodiment of the present invention is used, it can be confirmed that a fuel cell having improved performance can be provided.

In this case, the first catalyst layer and the second catalyst layer are each independently selected from the group consisting of platinum, palladium, cobalt, gold, ruthenium, tin, molybthenium, rhodium, iridium, bismuth, copper, yttrium and chromium. It may be characterized by including the above metal catalyst, but is not limited thereto, and any metal catalyst that can be used in the hydrogen oxidation reaction can be used without limitation.

In this case, the weight per unit area (M/A) of the metal catalyst with respect to the entire catalyst layer including the first catalyst layer and the second catalyst layer is 0.1 mg/cm ² to 0.5 mg/cm ² It may be characterized as being

The weight per unit area (M/A) of the metal catalyst with respect to the entire catalyst layer including the first catalyst layer and the second catalyst layer is 0.1 mg/cm ² If it is less than, it is not preferable because the catalyst content is too small and it is difficult to sufficiently secure fuel cell efficiency.

The weight per unit area (M/A) of the metal catalyst with respect to the entire catalyst layer including the first catalyst layer and the second catalyst layer is 0.5 mg/cm ² If it exceeds, the required amount of a metal catalyst, which is expensive, is increased, which is not preferable in terms of cost.

Therefore, the weight per unit area (M/A) of the metal catalyst with respect to the entire catalyst layer including the first catalyst layer and the second catalyst layer is 0.1 mg/cm ² to 0.5 mg/cm ² It is preferable to be

More preferably, the weight per unit area (M/A) of the metal catalyst with respect to the entire catalyst layer including the first catalyst layer and the second catalyst layer is 0.2 mg/cm ² to 0.3 mg/cm ² It may be characterized as being

As described above, the amount of the metal catalyst supported on the catalyst layer of the present invention is less than half compared to that of about 1 mg/cm ² of the metal catalyst supported on the fuel cell catalyst layer according to the conventional technology.

In general, a metal catalyst used in a fuel cell requires a catalyst having a low activation energy barrier, and thus noble metals such as platinum, ruthenium, iridium, gold, and silver are mainly used. These noble metal catalysts have the advantage of being suitable for use as an active catalyst due to their low adsorption energy, but have a high cost problem due to their scarcity.

Accordingly, the present invention improves the cell performance by configuring the catalyst layer using the two types of hydrophobic binders as described above, thereby reducing the unit cost of the fuel cell because it is possible to provide a similar or improved output with less metal catalyst usage than the conventional fuel cell catalyst layer. It has a mitigating effect.

In this case, the weight ratio of the metal catalyst supported on the first catalyst layer and the metal catalyst supported on the second catalyst layer may be 1:9 to 6:4.

When the weight ratio of the metal catalyst supported on the first catalyst layer and the metal catalyst supported on the second catalyst layer is less than 1:9, it is not preferable because the PTFE layer is thin and phosphoric acid leakage occurs.

When the weight ratio of the metal catalyst supported on the first catalyst layer and the metal catalyst supported on the second catalyst layer exceeds 6:4, the phosphoric acid content in the electrode is reduced, which is not preferable because performance is reduced.

In this case, the first catalyst layer may be formed on the gas diffusion layer through spray coating.

The binder of the present invention used for the first catalyst layer is characterized in that it has superhydrophobic properties like PTFE. Because these binders do not dissolve well in solvents due to their properties, other processes for forming a catalyst layer in an existing fuel cell, for example, bar coating, screen printing, and spin coating are not suitable for use. In addition, since the gas diffusion layer of the present invention is characterized in that it does not particularly include a microporous layer, it contains relatively large pores. It is not suitable because the composition for forming the catalyst layer is lost through the pores.

Accordingly, the first catalyst layer may be preferably formed on the gas diffusion layer through spray coating.

Since the binder of the present invention used for the second catalyst layer has less hydrophobic properties than the PTFE binder of the first catalyst layer, it is relatively well soluble in a solvent, and thus is formed on the first catalyst layer by a method other than a spray method. can be

For example, the second catalyst layer may be formed on the gas diffusion layer through bar coating, but is not limited thereto.

As described above, the anode electrode of the fuel cell has the effect of preventing phosphoric acid from leaking, but in order to improve the efficiency of the fuel cell, the catalyst layer needs to support phosphoric acid at a certain level or more.

At this time, the second catalyst layer is formed in a form in which many cracks, ie, large pores, are present.

Therefore, since a large amount of phosphoric acid can be impregnated inside the crack formed as described above, the anode electrode for a fuel cell according to an embodiment of the present invention simultaneously satisfies the phosphoric acid leakage prevention and sufficient phosphoric acid impregnation effect as described above. possible effect.

Due to the characteristics of the above configuration, according to an embodiment of the present invention, the catalyst layer is configured as a double layer using two kinds of binders having different hydrophobic properties, thereby preventing phosphoric acid leakage of the electrode and securing sufficient phosphoric acid loading. There is an effect that it is possible to provide an anode electrode for a fuel cell that can be driven with high efficiency even at a high temperature.

A membrane electrode assembly according to another embodiment of the present invention will be described.

The membrane electrode assembly may include an anode electrode for a fuel cell according to an embodiment of the present invention.

The description of the anode electrode for the fuel cell is replaced with that described in the above embodiment.

A fuel cell according to another embodiment of the present invention will be described.

The fuel cell may include an anode electrode for a fuel cell according to an embodiment of the present invention.

The description of the anode electrode for the fuel cell is replaced with that described in the above embodiment.

Due to the characteristics of the above configuration, according to an embodiment of the present invention, there is an effect that it is possible to provide a fuel cell that can be driven with high efficiency even at a high temperature.

A method of manufacturing an anode electrode for a fuel cell according to another embodiment of the present invention will be described.

Some of the components of the embodiment of the present invention are the same as those of the embodiment of the present invention, and accordingly, the description of the same components will be omitted or simply described.

The manufacturing method of the anode electrode for a fuel cell includes the steps of: preparing a composition for forming a first catalyst layer including a first binder and a metal catalyst; forming a first catalyst layer by applying the composition for forming a first catalyst layer on a gas diffusion layer; preparing a composition for forming a second catalyst layer including a second binder and a metal catalyst; and forming a second catalyst layer by applying the composition for forming a second catalyst layer on the first catalyst layer.

At this time, the gas diffusion layer is characterized in that it does not include a microporous layer, the first binder is characterized in that it is PTFE, and the second binder is a hydrophobic binder of a different type from the PTFE. can do.

As described above, by configuring the gas diffusion layer and the catalyst layer of the present invention as described above, it is possible to provide a fuel cell capable of driving with high efficiency even at high temperature by securing sufficient phosphoric acid loading while preventing phosphoric acid leakage from the electrode.

At this time, the composition for forming the first catalyst layer in the step of preparing the composition for forming the first catalyst layer is obtained by mixing 40 wt% of a platinum catalyst, 60 wt% of a PTFE binder solution, a surfactant, and an IPA mixed solvent. can

The step of preparing the composition for forming the first catalyst layer,

First mixing the composition prepared as described above at room temperature using sonication;

Secondary mixing of the first mixed composition at room temperature using ultra-sonification; and

A third mixing step by stirring the second mixed composition at 13000 RPM for 1 hour using a homogenizer; may include.

The step of forming the first catalyst layer,

After applying the composition to the gas diffusion layer by using spray, the first drying step of the formed electrode on a hot plate (hot plate) at 80 ℃; and

Secondary drying of the firstly dried electrode in an Ar atmosphere in a tube furnace at 307° C. for 15 minutes may include.

In this case, the composition for forming the second catalyst layer in the step of preparing the composition for forming the second catalyst layer may be obtained by mixing 20 wt% of a platinum catalyst, a PVDF binder, a viscosity modifier, and NMP.

The step of preparing the composition for forming the second catalyst layer,

It may include; mixing the composition prepared as described above by stirring at 250 RPM for 1 hour through ball milling.

The step of forming the second catalyst layer,

applying the composition on the first catalyst layer; and

drying the electrode formed in the above step in a convection oven at 60° C. for 24 hours.

Due to the characteristics of the above configuration, according to an embodiment of the present invention, the catalyst layer is configured as a double layer using two kinds of binders having different hydrophobic properties, thereby preventing phosphoric acid leakage of the electrode and securing sufficient phosphoric acid loading. There is an effect that it is possible to provide a method for manufacturing an anode electrode for a fuel cell that can be driven with high efficiency even at a high temperature.

Hereinafter, the present invention will be described in more detail through Examples, Comparative Examples and Experimental Examples. However, the present invention is not limited to the following Examples and Experimental Examples.

<Example 1>

In order to manufacture a fuel cell according to an embodiment of the present invention, an anode electrode for a fuel cell was manufactured.

2 is a view showing an SEM image of the anode electrode of the membrane electrode assembly manufactured according to the embodiment of the present invention.

In order to prepare the anode electrode for the fuel cell, first, a PTFE binder mixed solution containing a Pt catalyst was prepared.

The PTFE binder mixture solution was prepared by mixing 20 g of distilled water and 5 g of IPA (Isopropyl alcohol) mixed with 40 wt% Pt/C 0.3 g, 60 wt% PTFE solution 0.0981 g, and surfactant 0.0325 g.

The prepared mixed solution is first mixed for 20 minutes at room temperature using sonication, the first mixed composition is secondarily mixed for 20 minutes at room temperature using ultra-sonification, and the second mixed composition is subjected to a homogenizer (homogenizer) was stirred at 13000 RPM for 1 hour to prepare a third mixing.

After applying the prepared mixed solution composition to the gas diffusion layer (JNT30) that does not contain MPL using spray, it is dried first on a hot plate at 80° C., and the dried electrode is dried in an Ar atmosphere. The first catalyst layer was formed by secondary drying for 15 minutes in a tube furnace at 307°C.

Then, a PVDF binder mixed solution containing a Pt catalyst was prepared.

The PVDF binder mixture solution was prepared by mixing 0.048 g of PVDF binder, 0.0075 g of a viscosity modifier, and 5.736 g of NMP (N-Methyl-2-pyrrolidone) with a Resodyn Acoustic Mixer, and adding 20 wt% of Pt/C. .

The prepared mixed solution was stirred at 250 RPM for 1 hour through ball milling.

The stirred mixed solution was applied on the first catalyst layer through bar coating and dried in a convection oven at 60° C. for 24 hours to form a second catalyst layer according to Example 1 of the present invention. An anode electrode was prepared.

At this time, the Pt catalyst supported on the entire catalyst layer including the first catalyst layer and the second catalyst layer has a weight per unit area (M/A) of 0.296 mg _metal /cm ² , the Pt catalyst supported on the first catalyst layer and the agent The Pt catalyst supported on the second catalyst layer was prepared to achieve a weight ratio of 5:5.

<Example 2>

In Example 1, the Pt catalyst supported on the entire catalyst layer including the first catalyst layer and the second catalyst layer had a weight per unit area (M/A) of 0.274 mg _metal /cm ² , and Pt supported on the first catalyst layer Example 2 was prepared under the same process conditions as in Example 1, except that the catalyst and the Pt catalyst supported on the second catalyst layer were prepared to have a weight ratio of 6:4.

<Example 3>

In Example 1, the Pt catalyst supported on the entire catalyst layer including the first catalyst layer and the second catalyst layer had a weight per unit area (M/A) of 0.258 mg _metal /cm ² , and Pt supported on the first catalyst layer Example 3 was prepared under the same process conditions as in Example 1, except that the catalyst and the Pt catalyst supported on the second catalyst layer were prepared to have a weight ratio of 8:2.

<Example 4>

In Example 1, the Pt catalyst supported on the entire catalyst layer including the first catalyst layer and the second catalyst layer had a weight per unit area (M/A) of 0.207 mg _metal /cm ² , and Pt supported on the first catalyst layer Example 4 was prepared under the same process conditions as in Example 1, except that the catalyst and the Pt catalyst supported on the second catalyst layer were prepared to have a weight ratio of 9:1.

<Comparative Example 1>

A commercially available anode electrode from Dongjin Semichem, which is widely used as an electrode for a fuel cell, was used as Comparative Example 1.

For the anode electrode of Dongjin Semichem, a product having a metal catalyst loading amount of 1 mg _metal /cm ² was used.

<Comparative Example 2>

A catalyst layer containing PTFE was formed under the same process conditions as in Example 1, except that the gas diffusion layer was prepared using a JNT30A3 product including an MPL layer, and the second catalyst layer was not formed. Comparative Example 2 was prepared under the same process conditions as in 1.

In this case, the Pt catalyst supported on the PTFE catalyst layer had a weight per unit area (M/A) of 0.296 mg _metal /cm ² .

<Comparative Example 3>

JNT30A3 comprising a catalyst layer containing PVDF under the same process conditions as in Example 1, but directly forming the PVDF catalyst layer on the gas diffusion layer without forming a first catalyst layer containing PTFE, and including an MPL layer as the gas diffusion layer Comparative Example 3 was prepared under the same process conditions as in Example 1, except that it was prepared using the product.

At this time, the Pt catalyst supported on the PVDF catalyst layer had a weight per unit area (M/A) of 0.297 mg _metal /cm ² .

<Comparative Example 4>

Comparative Example 4 was prepared under the same process conditions as in Comparative Example 3, except that H23C2 having little cracks was used as the gas diffusion layer in Comparative Example 3.

At this time, the Pt catalyst supported on the PVDF catalyst layer had a weight per unit area (M/A) of 0.269 mg _metal /cm ² .

Table 1 below is a table summarizing the process conditions of Examples 1 to 4 and Comparative Examples 1 to 4, and the like.

[Table 1]

<Experimental example>

An experiment was conducted by manufacturing a membrane electrode assembly using the anode electrode for a fuel cell prepared in Examples and Comparative Examples.

The membrane electrode assembly was prepared under the following conditions.

- Cathode: BASF GDE (Pt loading: 1.0mg _Pt /cm ² )

- Membrane : Celtec® membrane

- Sub Gasket : 50νm Kapton

- Gasket : Teflon (Gasket/GDE = 0.7~0.8 (thickness ratio))

- H ₂ (dry): 100mL/min, Air (dry): 300mL/min

<Experimental Example 1> Membrane electrode assembly performance comparison experiment

An experiment was conducted to compare the performance of the membrane electrode assembly including the anode electrode for a fuel cell prepared in Examples and Comparative Examples. At this time, the experiment was carried out at a driving temperature of 150 °C.

3 is a graph showing voltage and power density per current density of membrane electrode assemblies according to Examples and Comparative Examples of the present invention.

4 is a graph showing voltage and peak power density of membrane electrode assemblies according to Examples and Comparative Examples of the present invention.

Table 2 below is a table summarizing voltages and peak power densities of membrane electrode assemblies according to Examples and Comparative Examples of the present invention.

[Table 2]

3, 4 and Table 2, as in the example of the present invention, a membrane electrode assembly having a catalyst layer composed of two types of hydrophobic binders in a gas diffusion layer without MPL includes only one type of binder. Compared with the example, there is an effect that an improved output can be provided even with a small catalyst loading amount.

<Experimental Example 2> Durability evaluation and phosphoric acid leakage measurement experiment

An experiment was conducted to evaluate the durability of the membrane electrode assembly including the anode electrode for a fuel cell prepared in Examples and Comparative Examples.

The durability evaluation experiment was conducted in a manner of observing a change in performance after maintaining at 0.2 A/cm ² at a driving temperature of 150° C. for 137 hours.

At this time, phosphoric acid leakage was measured by collecting the gas discharged during the durability evaluation experiment in H ₂ O and detecting phosphoric acid through ICP-MS analysis.

FIG. 5 is a graph showing voltage changes according to time of membrane electrode assemblies according to Examples and Comparative Examples of the present invention.

Table 3 below is a table summarizing the voltage, phosphoric acid outflow from the anode, phosphoric acid outflow from the cathode, and total phosphoric acid outflow of membrane electrode assemblies according to Examples and Comparative Examples of the present invention.

[Table 3]

5 and Table 3, it can be seen that Example 1 of the present invention has a higher voltage even after 137 hours have passed than Comparative Example 1, and phosphoric acid is not leaked from the anode at all. It can be seen that the amount of phosphoric acid outflow decreased by about 1/9 times or more.

<Experimental Example 3> TGA analysis experiment

An experiment was conducted to analyze the anode electrode for a fuel cell prepared in Example 1 by TGA.

To this end, the upper surface of the electrode made of the double layer prepared in Example 1 was cut off, and then the entire electrode before cutting (Example 1), the cut top part (Example 1 (top)), and the cut bottom part (Example 1 (Example 1) bottom)) to measure the TGA of each sample.

The TGA measurement was carried out at 0 to 1000° C. under N ₂ atmosphere.

6 is a schematic diagram schematically illustrating a process of obtaining a sample for TGA analysis by cutting the upper end of the anode electrode for a fuel cell prepared in Example 1 of the present invention.

7 is a graph showing TGA analysis of each partial sample of an anode electrode for a fuel cell.

6 and 7, when the double-layer electrode is analyzed by TGA in an N ₂ atmosphere, it can be seen that a total of four inflection points are shown.

At this time, the first inflection point is by a viscosity thickener around 120℃, the second inflection point by PVDF near 260℃, the third inflection point by PTFE around 470℃, and the fourth inflection point by carbon around 800℃ You can check each occurrence.

Then, when the upper part sample (Example 1 (top)) and the lower part sample (Example 2 (bottom)) of the anode electrode double layer for a fuel cell according to Example 1 are analyzed by each TGA, the inflection points are the same at four places. can be seen to appear.

However, the weight ratio reduced at each temperature is different, which means that the binder composition of the upper part and the lower part of the anode electrode for a fuel cell according to Example 1 is different, and thus it can be confirmed that the two layers are manufactured with different compositions.

The above description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

10: gas diffusion layer
20: first catalyst layer
30: second catalyst layer

Claims (12)

a gas diffusion layer that does not include a microporous layer;
a first catalyst layer positioned on the gas diffusion layer and including a first binder; and
A second catalyst layer positioned on the first catalyst layer, the second catalyst layer including a second binder;
The first binder is characterized in that PTFE,
The second binder is an anode electrode for a fuel cell, characterized in that the PTFE and a different type of hydrophobic binder. According to claim 1,
The gas diffusion layer is an anode electrode for a fuel cell, characterized in that it comprises any one or more selected from the group consisting of carbon cloth (carbon cloth), carbon paper (carbon paper) and carbon felt (carbon felt). According to claim 1,
The second binder is an anode electrode for a fuel cell, characterized in that it has a relatively lower hydrophobicity than PTFE. According to claim 1,
The second binder is an anode electrode for a fuel cell, characterized in that it comprises any one or more selected from the group consisting of PVDF, PBI, PVA and PAA. According to claim 1,
The first catalyst layer and the second catalyst layer are each independently any one or more metals selected from the group consisting of platinum, palladium, cobalt, gold, ruthenium, tin, molybthenium, rhodium, iridium, bismuth, copper, yttrium and chromium. Anode electrode for fuel cell, characterized in that it contains a catalyst. 6. The method of claim 5,
The weight per unit area (M/A) of the metal catalyst with respect to the entire catalyst layer including the first catalyst layer and the second catalyst layer is 0.1 mg/cm ² to 0.5 mg/cm ² Anode electrode for fuel cell, characterized in that. 7. The method of claim 6,
A weight ratio of the metal catalyst supported on the first catalyst layer and the metal catalyst supported on the second catalyst layer is 1:9 to 6:4. According to claim 1,
The first catalyst layer is an anode electrode for a fuel cell, characterized in that formed on the gas diffusion layer through a spray (spray). A membrane electrode assembly comprising the anode electrode for a fuel cell according to claim 1 . A fuel cell comprising the anode electrode for a fuel cell according to claim 1 . preparing a composition for forming a first catalyst layer including a first binder and a metal catalyst;
forming a first catalyst layer by applying the composition for forming a first catalyst layer on a gas diffusion layer;
preparing a composition for forming a second catalyst layer including a second binder and a metal catalyst; and
forming a second catalyst layer by applying the composition for forming the second catalyst layer on the first catalyst layer;
The gas diffusion layer is characterized in that it does not include a microporous layer,
The first binder is characterized in that PTFE,
The second binder is a method of manufacturing an anode electrode for a fuel cell, characterized in that the PTFE and a different type of hydrophobic binder. 12. The method of claim 11,
In the forming of the first catalyst layer, the composition for forming the first catalyst layer is applied on the gas diffusion layer through a spray process to form the first catalyst layer. .

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