JP7272319B2 - Laminates for fuel cells - Google Patents

Description

The present invention relates to laminates for fuel cells.

Fuel cells are known that generate electricity by chemically reacting an anode gas such as hydrogen and a cathode gas such as oxygen.

In a fuel cell, an anode gas (fuel gas) such as hydrogen and a cathode gas (oxidant gas) such as oxygen are supplied to two electrically connected electrodes, respectively, to electrochemically oxidize the fuel. directly converts chemical energy into electrical energy.

At the anode (fuel electrode) to which hydrogen is supplied as the anode gas, the reaction of the following formula (a) proceeds.
H ₂ → 2H ⁺ + 2e ^- (a)

The electrons (e ⁻ ) generated in the above formula (1) reach the cathode (oxidant electrode) after going through an external circuit and working on an external load. On the other hand, the protons (H ⁺ ) generated in the above formula (a) move from the anode side to the cathode side in the electrolyte membrane sandwiched between the anode and the cathode by electroosmosis while being hydrated with water. do.

On the other hand, at the cathode, the protons (H ⁺ ) generated by the above formula (a) that passed through the electrolyte membrane, the oxygen supplied as the cathode gas, and the electrons (e ^- ) advances the reaction of the following formula (b).
2H ⁺ + 1/2O ₂ + 2e ⁻ → H ₂ O (b)

Therefore, the chemical reaction represented by the following formula (c) proceeds in the entire battery, an electromotive force is generated, and electrical work is performed on the external load.
H ₂ + 1/2O ₂ → H ₂ O (c)

Such a fuel cell is generally constructed by stacking a plurality of unit cells each having a basic structure of a membrane electrode assembly in which an electrolyte membrane is sandwiched between a pair of electrodes. Among them, a solid polymer electrolyte fuel cell using a solid polymer electrolyte membrane as an electrolyte membrane has advantages such as easy miniaturization and low temperature operation, and is particularly useful in mobile devices. It is expected to be used as a portable power source or a power source for mobile objects such as electric vehicles.

Here, the configuration of a single cell of a solid polymer electrolyte fuel cell includes, for example, an anode-side separator, an anode-side gas diffusion layer, an anode-side catalyst layer, an electrolyte membrane, a cathode-side catalyst layer, a cathode-side gas diffusion layer, and A laminate in which cathode-side separators are laminated in this order is known.

Here, in a fuel cell, the anode tends to dry out under high temperature and low humidity conditions. As drying progresses, resistive polarization increases and cell performance deteriorates. In addition, a decrease in output at high temperatures cannot be avoided. In response to this, it has been proposed to use the water generated at the cathode by sending it to the anode side (see Patent Document 1).

In Patent Document 1, among the layers constituting the laminate, the thickness of the cathode-side catalyst layer is made larger than the thickness of the anode-side catalyst layer, and the thickness of the anode-side gas diffusion layer is made larger than the thickness of the cathode-side gas diffusion layer. A technique has been proposed in which the thickness of each layer constituting the laminate is increased and the thickness of each layer constituting the laminate is set in a specific relationship to promote the movement of water from the cathode side to the anode side.

JP 2016-081581 A

However, the inventors of the present invention believe that if the thickness of the cathode-side catalyst layer is greater than the thickness of the anode-side catalyst layer, the heat capacity increases, the rate of temperature rise slows down, and the startability of the battery below freezing may deteriorate. I got the knowledge of Specifically, as the thickness of the cathode-side catalyst layer increases, the heat capacity increases, so the amount of heat required for temperature rise increases, resulting in the temperature rise rate of the laminate constituting the battery. becomes slower, and startability worsens below freezing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and provides a laminate for a fuel cell that can promote the movement of water from the cathode side to the anode side while ensuring startability at below freezing temperatures. intended to

The inventor of the present invention has made intensive studies to solve the above problems. Then, if the respective thicknesses of the anode catalyst layer, the electrolyte membrane, and the cathode catalyst layer, which constitute the membrane electrode assembly for the fuel cell, have a specific relationship, the thickness of the cathode catalyst layer is set to the thickness of the anode catalyst layer. The present inventors have found that startability can be ensured even when the thickness is greater than the thickness of , and have completed the present invention. That is, the present invention is as follows.

A laminate for a fuel cell in which an anode catalyst layer, an electrolyte membrane, and a cathode catalyst layer are laminated in this order,
When the thickness of the anode-side catalyst layer is D1, the thickness of the electrolyte membrane is D2, and the thickness of the cathode-side catalyst layer is D3, the following formulas (1) and (2) are satisfied.
Laminates for fuel cells.
D3>3.0×D1 (1)
D1>1/3×D2 (2)

According to the laminate for a fuel cell of the present invention, even when the thickness of the cathode-side catalyst layer is made larger than the thickness of the anode-side catalyst layer, it is possible to ensure startability at sub-zero temperatures. , it is possible to realize a fuel cell in which sub-zero startability is ensured while promoting movement of water to the anode side.

1 is a cross-sectional view of a laminate for a fuel cell of the present invention according to one embodiment; FIG. 4 is a graph showing the relationship between the ratio of the thickness of the anode-side catalyst layer to the thickness of the electrolyte membrane and the water content of the cell at startup. 4 is a graph showing the relationship between the ratio of the thickness of the cathode-side catalyst layer to the thickness of the anode-side catalyst layer and the allowable water content.

Embodiments of the present invention will be described in detail below. It should be noted that the present invention is not limited to the following embodiments, and can be implemented in various modifications.

《Laminates for fuel cells》
A fuel cell laminate of the present invention is at least a part of a laminate constituting a fuel cell, and is a laminate in which an anode catalyst layer, an electrolyte membrane, and a cathode catalyst layer are laminated in this order. is. The respective thicknesses of the anode-side catalyst layer, the electrolyte membrane, and the cathode-side catalyst layer have a specific relationship.

In the fuel cell laminate of the present invention, the thicknesses of the anode catalyst layer, the electrolyte membrane, and the cathode catalyst layer have a specific relationship, so that the thickness of the cathode catalyst layer is equal to that of the anode catalyst layer. Even when the thickness is larger than the thickness, it is possible to realize a fuel cell that can ensure startability at subzero temperatures.

The fuel cell laminate of the present invention may contain other layers as long as the anode catalyst layer, the electrolyte membrane, and the cathode catalyst layer are essential components. That is, the minimum unit constituent of the fuel cell laminate of the present invention is a so-called membrane electrode assembly. Examples of other layers include gas diffusion layers and separators, but are not limited to these.

The structure of a laminate stored in a general fuel cell includes, for example, an anode-side separator, an anode-side gas diffusion layer, an anode-side catalyst layer, an electrolyte membrane, a cathode-side catalyst layer, a cathode-side gas diffusion layer, and a cathode. A laminate in which the side separators are laminated in this order can be mentioned.

FIG. 1 is a cross-sectional view of a fuel cell stack according to one embodiment of the present invention. In FIG. 1, the membrane electrode assembly 100 is an embodiment of the minimum unit of the fuel cell laminate according to the present invention. A laminate 200 including a membrane electrode assembly 100 includes an anode-side gas diffusion layer 40 in which an anode-side porous substrate layer 41 and an anode-side microporous layer 42 are laminated, an anode-side catalyst layer 10, an electrolyte membrane 30, a cathode-side The catalyst layer 20 and the cathode-side gas diffusion layer 50 in which the cathode-side porous substrate layer 51 and the cathode-side microporous layer 52 are laminated are laminated in this order.

In FIG. 1, D1 is the thickness of the anode-side catalyst layer, D2 is the thickness of the electrolyte membrane, and D3 is the thickness of the cathode-side catalyst layer.

In the fuel cell laminate of the present invention, the respective thicknesses of the anode catalyst layer, the electrolyte membrane, and the cathode catalyst layer have specific relationships. That is, in the membrane electrode assembly 100 shown in FIG. 1, the thickness D1 of the anode catalyst layer, the thickness D2 of the electrolyte membrane, and the thickness D3 of the cathode catalyst layer have a specific relationship.

<Catalyst layer>
The catalyst layer is an essential constituent layer in the fuel cell laminate of the present invention. The laminate for a fuel cell of the present invention includes, as catalyst layers, an anode side catalyst layer and a cathode side catalyst layer, with an electrolyte membrane disposed therebetween.

The anode-side catalyst layer has a function of decomposing hydrogen (H ₂ ), which is a reaction gas, into protons (H ⁺ ) and electrons (e ⁻ ). On the other hand, the cathode-side catalyst layer has the function of generating water (H ₂ O) from protons (H ⁺ ), electrons (e ⁻ ), and oxygen (O ₂ ).

The catalyst layers on the anode side and cathode side can be made of similar materials. For example, a conductive carrier supporting a catalyst such as platinum or a platinum alloy is used, and more specifically, a catalyst-supporting carbon in which a catalyst is supported on carbon particles such as carbon black that functions as a conductive substance. Examples include a layer composed of particles and an electrolyte component that exhibits proton conductivity due to ion exchange groups, which is a component of the electrolyte membrane described above. A layer formed by coating the catalyst-supporting carbon particles with an electrolyte component such as an ionomer having proton conductivity may be used.

In the fuel cell laminate of the present invention, the thickness of the cathode-side catalyst layer is more than three times the thickness of the anode-side catalyst layer. That is, when the thickness of the anode side catalyst layer is D1 and the thickness of the cathode side catalyst layer is D3, the fuel cell laminate of the present invention satisfies the following formula (1).
D3>3.0×D1 (1)

By satisfying the above formula (1), the movement of water from the cathode side to the anode side can be promoted.

The thickness D1 of the anode-side catalyst layer and the thickness D3 of the cathode-side catalyst layer may have the relationship of the following formula (1a) or the following formula (1b).
D3>3.5×D1 (1a)
D3>4.0×D1 (1b)

Further, in the fuel cell laminate of the present invention, the thickness D1 of the anode side catalyst layer and the thickness D3 of the cathode side catalyst layer may satisfy the relationship of the following formula (1c), or the following formula (1d). may be a relationship of
D3<6.0×D1 (1c)
D3<5.0×D1 (1d)

In the fuel cell laminate of the present invention, the thicknesses of the anode side catalyst layer and the cathode side catalyst layer are not particularly limited as long as the above relationship can be satisfied. It can be appropriately set according to the application.

The thicknesses of the anode-side catalyst layer and the cathode-side catalyst layer in the present invention may be average values obtained by measuring arbitrary 10 points of each layer.

<Electrolyte membrane>
The electrolyte membrane is an essential constituent layer in the fuel cell laminate of the present invention. The electrolyte membrane has the function of blocking the flow of electrons and gases, and of transferring protons (H ⁺ ) generated at the anode from the anode-side catalyst layer to the cathode-side catalyst layer.

In the fuel cell laminate of the present invention, the thickness of the anode-side catalyst layer is greater than ⅓ of the thickness of the electrolyte membrane. That is, when the thickness of the anode catalyst layer is D1 and the thickness of the electrolyte membrane is D2, the fuel cell laminate of the present invention satisfies the following formula (2).
D1>1/3×D2 (2)

By satisfying the above formula (2), the heat capacity of the laminate can be reduced even when the above formula (1) is satisfied. As a result, it is possible to ensure startability at subzero temperatures while facilitating movement of water from the cathode side to the anode side.

The thickness D1 of the anode-side catalyst layer and the thickness D2 of the electrolyte membrane may have the relationship of the following formula (2a) or the following formula (2b).
D1>2/5×D2 (2a)
D1>2/3×D2 (2b)

Moreover, in the fuel cell laminate of the present invention, the thickness of the electrolyte membrane is preferably larger than the thickness of the anode-side catalyst layer. That is, the relationship between the thickness D1 of the anode-side catalyst layer and the thickness D2 of the electrolyte membrane preferably satisfies the following formula (2c), or may satisfy the following formula (2d).
D1<1×D2 (2c)
D1<5/6×D2 (2d)

Moreover, in the fuel cell laminate of the present invention, the thickness of the electrolyte membrane is preferably smaller than the thickness of the cathode-side catalyst layer. That is, the thickness D2 of the electrolyte membrane and the thickness D3 of the cathode-side catalyst layer preferably have the relationship of the following formula (3a), or may have the relationship of the following formula (3b).
D2<1.0×D3 (3a)
D2<4/5×D3 (3b)

In the fuel cell laminate of the present invention, the thickness of the electrolyte membrane is not particularly limited as long as the above relationship is satisfied. It can be appropriately set according to the application. The thickness of the electrolyte membrane may be, for example, 10 μm or less.

In addition, the thickness of the electrolyte membrane in the present invention may be an average value obtained by measuring arbitrary 10 points of the electrolyte membrane.

The electrolyte membrane is not particularly limited, and known membranes as electrolyte membranes used in fuel cells can be used. In the case of a solid polymer electrolyte fuel cell using a solid polymer electrolyte membrane as the electrolyte membrane, for example, an ion-conducting polymer electrolyte resin formed of a polymer electrolyte resin containing sulfonic acid groups such as perfluorosulfonic acid (PFSA) ionomer. an ion-exchange membrane having properties. The membrane is not limited to sulfonic acid groups, and may include other ion exchange groups (electrolyte components) such as phosphoric acid groups and carboxylic acid groups.

In the present invention, a commercially available ion exchange membrane may be applied, which is formed of a polymer electrolyte resin, which is a solid polymer material such as perfluorosulfonic acid (PFSA) ionomer, and has ion conductivity. It consists of an ion-exchange membrane with a polymer membrane as an electrolyte. Examples of commercially available fluororesin-based ion exchange membranes containing sulfonic acid groups include Nafion (registered trademark) manufactured by DuPont, Aciplex (registered trademark) manufactured by Asahi Kasei Corporation, and Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd. etc.

<Gas diffusion layer>
The gas diffusion layer is an optional layer in the fuel cell laminate of the present invention. The gas diffusion layer is arranged adjacent to the anode-side catalyst layer and the cathode-side catalyst layer, and has the function of diffusing and uniforming the reactant gas to be supplied and spreading the gas over the adjacent catalyst layers.

Generally, the gas diffusion layer is a laminated body in which a porous substrate layer and a microporous layer are laminated. The microporous layer then faces the adjacent catalyst layer.

(Porous substrate layer)
The porous substrate layer in the gas diffusion layer is a porous layer that supplies reaction gas to the adjacent catalyst layer. The porous substrate layer is preferably made of a material having gas permeability and electrical conductivity.

In the present invention, any material that is commonly used as a porous substrate layer can be used without particular limitation. For example, carbon porous bodies such as carbon paper or carbon cloth, metal mesh or Metal porous bodies, such as foam metal, etc. can be mentioned. Incidentally, the porous carbon body such as carbon paper or carbon cloth may be formed of, for example, carbon fiber and a binder such as a resin that is carbonized by firing.

The pore size, density, thickness, etc. of the porous base material layer constituting the gas diffusion layer are not particularly limited, and can be appropriately set according to the required performance of the fuel cell to be formed.

(Microporous layer (MPL))
The microporous layer in the gas diffusion layer is the layer that overlies the porous substrate layer and is adjacent to the catalyst layer. By forming the MPL on the gas diffusion layer that constitutes the fuel cell laminate, the gas diffusion property in the fuel cell is improved.

The method for producing the microporous layer (MPL) is not particularly limited. A method of discharging from a coating head, coating, and then drying and baking may be used.

The MPL-forming slurry or MPL-forming paste is not particularly limited, but is generally a composition containing carbon particles and a water-repellent resin as main components. Therefore, the MPL becomes a layer containing these as main components.

Examples of carbon particles include particles of carbon black, graphene, graphite, and the like.

The carbon particles may have an average primary particle size of 25 nm to 70 nm. The average primary particle size of the carbon particles may be 25 nm or more, 45 nm or more, or 65 nm or more, and may be 70 nm or less, 60 nm or less, or 50 nm or less.

The average primary particle diameter of the carbon particles is determined by using an electron microscope such as a transmission electron microscope (TEM) or a scanning electron microscope (SEM) to determine the directional diameter (Feret diameter), and the arithmetic mean of the obtained measured values.

Examples of water-repellent resins include fluorine-based polymer materials such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyhexafluoropropylene, and tetrafluoroethylene-hexafluoropropylene copolymer, polypropylene, Polyethylene etc. can be mentioned.

The thickness of the microporous layer (MPL) that constitutes the gas diffusion layer is not particularly limited, and can be appropriately set according to the required performance of the fuel cell to be formed. For example, it may be 20 μm or more.

Hereinafter, the present invention will be described in more detail by showing experimental results.

In the experimental examples, the thickness of the electrolyte membrane was fixed, and the thickness of the anode side catalyst layer (Experimental example 1) and the thickness of the cathode side catalyst layer (Experimental example 2) were varied to fabricate a total of 12 fuel cells. bottom. The six fuel cells fabricated in Experimental Example 1 were evaluated for cell water content at start-up, and the six fuel cells fabricated in Experimental Example 2 were evaluated for capacity water content.

Note that the cell water content at start-up is the amount of water remaining after scavenging and wastewater treatment assuming a sub-zero start after power generation, and is an index for the startability of the fuel cell at sub-zero temperatures. The lower the cell water content at start-up, the better the startability of the fuel cell below freezing.

Also, the allowable water content is the amount of generated water converted from the total amount of electric current at sub-zero starting, and serves as an index for the startability of the fuel cell at sub-zero temperatures. If the permissible water content of the fuel cell is sufficiently high, it means that the reaction of the fuel cell is progressing sufficiently, which means that the startability of the fuel cell is good at temperatures below freezing.

Therefore, in general, there is a correlation between the cell water content at startup and the allowable water content, and when the cell water content at startup decreases, the allowable water content increases.

<<Experimental Example 1>> The relationship between the ratio of the thickness (D1) of the anode catalyst layer to the thickness (D2) of the electrolyte membrane and the water content of the cell at startup In Experimental Example 1, the thickness (D2) of the electrolyte membrane was fixed. , and the thickness (D1) of the anode-side catalyst layer was varied to fabricate six fuel cells. The cell water content at start-up was evaluated for the six fuel cells obtained.

<Fabrication of fuel cell>
(Preparation of gas diffusion layer)
Twelve sheets of carbon paper were prepared as porous substrates. A slurry for forming a microporous layer (MPL) containing carbon particles and polytetrafluoroethylene (PTFE) is applied to the surface of each carbon paper with a die coater, dried and then baked to form a porous substrate layer. A gas diffusion layer was prepared by laminating a microporous layer (MPL) on the substrate.

(Production of membrane electrode assembly (MEA))
As electrolyte membranes, six membranes containing a fluorine-based proton conductive polymer having a thickness of 9 μm were prepared.

A cathode-side catalyst layer forming ink containing platinum alloy-supported carbon particles and an ionomer was applied to one surface of the electrolyte membrane and dried to form a cathode-side catalyst layer.

Subsequently, a composition containing platinum-supported carbon particles and an ionomer was prepared as an ink for forming an anode-side catalyst layer. An anode-side catalyst layer-forming ink was applied to the surface of the electrolyte membrane on which no cathode-side catalyst layer was formed, and dried to form an anode-side catalyst layer, thereby producing a membrane electrode assembly (MEA). The thickness (D1) of the anode-side catalyst layer of the six membrane electrode assemblies thus produced was different.

(Fabrication of fuel cell)
Using two of the gas diffusion layers prepared above and one sheet of the membrane electrode assembly (MEA) prepared above, anode-side gas diffusion layer/anode-side catalyst layer/electrolyte membrane/cathode-side catalyst By stacking layers in the order of layer/cathode-side gas diffusion layer and sandwiching them between a pair of separators, six fuel cells with different anode-side catalyst layer thicknesses (D1) were produced.

The anode-side catalyst layer and the cathode-side catalyst layer were arranged so that the microporous layers (MPL) of the adjacent gas diffusion layers faced each other.

<Evaluation of cell water content at start-up>
The cell water content at start-up was evaluated for the six types of fuel cells produced. The cell water content at start-up was obtained by measuring the dry weight of the cell in advance and subtracting the dry weight from the weight of the cell after scavenging and drainage treatment assuming sub-zero start-up after power generation.

For each battery, the ratio of the thickness (D1) of the anode-side catalyst layer to the thickness (D2) of the electrolyte membrane was determined, and plotted in FIG. The horizontal axis of the graph is the ratio of the thickness (D1) of the anode-side catalyst layer to the thickness (D2) of the electrolyte membrane, and the vertical axis of the graph is the reciprocal of the cell water content at startup of the obtained fuel cell. indicate a value.

From FIG. 2, if the thickness (D1) of the anode-side catalyst layer is greater than 1/3 of the thickness (D2) of the electrolyte membrane, the cell water content at start-up will be appropriate. It can be seen that the properties are improved.

<<Experimental Example 2>> Relationship between the ratio of the thickness (D2) of the cathode-side catalyst layer to the thickness (D1) of the anode-side catalyst layer and the allowable water content In Experimental Example 2, the thickness (D2) of the electrolyte membrane was fixed, Six fuel cells were produced by changing the thickness (D1) of the anode side catalyst layer and the thickness (D3) of the cathode side catalyst layer. The permissible water content was evaluated for the six fuel cells obtained.

<Fabrication of fuel cell>

(Production of membrane electrode assembly (MEA))
As electrolyte membranes, six membranes containing a fluorine-based proton conductive polymer having a thickness of 9 μm were prepared.

A cathode-side catalyst layer forming ink containing platinum alloy-supported carbon particles and an ionomer was applied to one surface of the electrolyte membrane and dried to form a cathode-side catalyst layer. In addition, the prepared cathode-side catalyst layers were different in thickness from each other.

Subsequently, a composition containing platinum-supported carbon particles and an ionomer was prepared as an ink for forming an anode-side catalyst layer. An anode-side catalyst layer-forming ink was applied to the surface of the electrolyte membrane on which no cathode-side catalyst layer was formed, and dried to form an anode-side catalyst layer, thereby producing a membrane electrode assembly (MEA). Note that the produced anode-side catalyst layers had different thicknesses.
(Preparation of gas diffusion layer)
Twelve sheets of carbon paper were prepared as porous substrates. In the same manner as in Experimental Example 1, a microporous layer (MPL) was formed on the surface of each carbon paper, and a gas diffusion layer was produced by stacking the microporous layer (MPL) on the porous substrate layer.

(Fabrication of fuel cell)
Using two of the gas diffusion layers prepared above and one sheet of the membrane electrode assembly (MEA) prepared above, anode-side gas diffusion layer/anode-side catalyst layer/electrolyte membrane/cathode-side catalyst By stacking layers in the order of layer/cathode-side gas diffusion layer and sandwiching them between a pair of separators, six fuel cells with different anode-side catalyst layer thicknesses (D1) and cathode-side catalyst layer thicknesses (D3) was made.

The anode-side catalyst layer and the cathode-side catalyst layer were arranged so that the microporous layers (MPL) of the adjacent gas diffusion layers faced each other.

<Battery Evaluation>
(Allowable water content)
The permissible water content was evaluated for the six types of fuel cells produced. In addition, the allowable water content was obtained by the following operation.

Start the battery while maintaining the cell temperature below freezing. The current can be swept for a while after starting, but when the generated water begins to freeze, the amount of current that can be swept gradually decreases, and at a certain point the current cannot be swept. The total amount of current swept from the start (total amount of current) was converted into coulombs, and the amount of water generated after the fuel cell was started was calculated as the allowable water content.

For each battery, the ratio of the thickness (D3) of the cathode side catalyst layer to the thickness (D1) of the anode side catalyst layer was obtained and plotted in FIG. 3 in combination with the obtained allowable water content. The horizontal axis of the graph is the ratio of the thickness (D3) of the cathode side catalyst layer to the thickness (D1) of the anode side catalyst layer, and the vertical axis of the graph is the relative value of the allowable water content of the obtained fuel cell. show.

From FIG. 3, if the thickness (D) of the cathode-side catalyst layer is three times or more the thickness (D1) of the anode-side catalyst layer, it has a sufficiently large allowable water content. can be ensured.

REFERENCE SIGNS LIST 100 membrane electrode assembly 200 laminate 10 anode side catalyst layer 20 cathode side catalyst layer 30 electrolyte membrane 40 anode side gas diffusion layer 41 anode side porous substrate layer 42 anode side microporous layer 50 cathode side gas diffusion layer 51 cathode side Porous substrate layer 52 Cathode-side microporous layer D1 Thickness of anode-side catalyst layer D2 Thickness of electrolyte membrane D3 Thickness of cathode-side catalyst layer

Claims (1)

A laminate for a fuel cell in which an anode catalyst layer, an electrolyte membrane, and a cathode catalyst layer are laminated in this order,
When the thickness of the anode-side catalyst layer is D1, the thickness of the electrolyte membrane is D2, and the thickness of the cathode-side catalyst layer is D3, the following formulas (1) and (2) are satisfied.
Laminates for fuel cells.
D3>3.0×D1 (1)
D1>1/3×D2 (2)

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