JP2012169173A - Fuel battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress strength degradation or the like due to sacrificial oxidation while suppressing oxidation of carbon in a catalyst layer.SOLUTION: In a fuel battery cell including an MEA 10, a gas diffusion sheet 12 and a separator 20, carbon is added as a sacrificial agent within a power generation surface of the gas diffusion sheet 12 so that the carbon is substantially perpendicular to the extending direction of a recessed part 22a functioning as a hydrogen-containing gas passage of the separator 20, the carbon having crystallinity lower than that of carbon in a catalyst layer. A projecting part 24 functioning as a coolant passage 24 functions as a rib, so that strength degradation due to sacrificial oxidation is reinforced.

Description

  The present invention relates to a fuel cell, and more particularly to a technique for suppressing oxidation of carbon in a catalyst layer.

  A polymer electrolyte fuel cell has a configuration in which a catalyst layer and a gas diffusion layer are sequentially laminated on both surfaces of a solid polymer electrolyte membrane having proton conductivity. In such a polymer electrolyte fuel cell, when the fuel is deficient, an electrolysis reaction of power generation generated water occurs for proton generation on the anode side, and protons can be supplied to the electrolyte membrane by this electrolysis reaction. If the electrolysis reaction does not proceed, the fuel electrode may deteriorate due to oxidation.

  In Patent Document 1 below, a fuel electrode for a fuel cell includes an anode catalyst layer for promoting protonation of hydrogen, a gas diffusion layer for diffusing fuel gas, and a plurality of water containing a water electrolysis catalyst. An arrangement comprising an electrocatalyst layer and a plurality of water electrocatalyst layers laminated between an anode catalyst layer and a gas diffusion layer is disclosed. The water electrocatalyst layer promotes electrolysis of water at the time of fuel depletion and suppresses deterioration of the catalyst layer, specifically, oxidation of carbon in the catalyst layer.

JP 2007-265929 A

  However, there is a possibility that the water electrocatalyst catalyst layer may elute and oxidize due to long-term use, and there is a risk that the catalytic function of the water electrolysis catalyst layer is lowered and the oxidation of carbon in the catalyst layer proceeds. Of course, it is possible to increase the amount of water electrocatalyst added on the premise of long-term use, but adding a large amount of material that does not contribute to the fuel cell reaction to the catalyst layer will inhibit gas diffusivity and proton conductivity. It is difficult to adjust the balance.

  Therefore, carbon having a lower crystallinity than that of the catalyst layer is mixed into the base material of the gas diffusion layer, so that the carbon having a lower crystallinity is selectively or preferentially oxidized than the carbon of the catalyst layer ( (Sacrificial oxidation) As a result, a method of suppressing oxidation of carbon in the catalyst layer is conceivable.

  However, even in this case, as the sacrificial oxidation progresses, the gas diffusibility may be hindered and the strength of the gas diffusion layer may be reduced. Therefore, it is preferable to cause the sacrificial oxidation uniformly in the gas diffusion layer. That is, since the degree of sacrificial oxidation may vary depending on the hydrogen wet state and the potential situation, it is necessary to cause sacrificial oxidation in consideration of this variation.

  The objective of this invention is providing the fuel cell which can suppress the oxidation of catalyst layer carbon, suppressing the strength reduction of a gas diffusion layer, etc.

  The present invention relates to a fuel cell, and is formed adjacent to the anode catalyst layer, the anode catalyst layer, a gas diffusion layer for diffusing a hydrogen-containing gas to be supplied to the anode catalyst layer, and the gas diffusion layer. And a separator for supplying the hydrogen-containing gas to the gas diffusion layer, wherein the separator has irregularities formed on a surface thereof, the hydrogen-containing gas passages are formed in the concave portions, and the refrigerant passages are formed in the convex portions. In the power generation surface of the gas diffusion layer, carbon having a lower crystallinity than that of the anode catalyst layer is added to function as a sacrificial oxidation region, and the gas diffusion layer The sacrificial oxidation region is formed so as to form a certain angle with respect to the extending direction of the hydrogen-containing gas channel.

  In one embodiment of the present invention, the sacrificial oxidation region of the gas diffusion layer is formed to be substantially perpendicular to the extending direction of the hydrogen-containing gas channel.

  The present invention is also a fuel cell, comprising: an anode catalyst layer; a gas diffusion layer that is formed adjacent to the anode catalyst layer and diffuses a hydrogen-containing gas to be supplied to the anode catalyst layer; and the gas diffusion layer. And a separator for supplying the hydrogen-containing gas to the gas diffusion layer. The separator has irregularities formed on the surface, the hydrogen-containing gas flow paths are formed in the concave portions, and the refrigerant flow is formed in the convex portions. In the power generation surface of the gas diffusion layer, carbon having a lower crystallinity than that of the anode catalyst layer is added to function as a sacrificial oxidation region, and the gas diffusion layer The sacrificial oxidation region is formed in a region facing the convex portion.

  In one embodiment of the present invention, the sacrificial oxidation region of the gas diffusion layer has a relatively small area and a relatively low current density in a region having a relatively large current density in the power generation surface. The area is relatively large.

  In another embodiment of the present invention, the sacrificial oxidation region of the gas diffusion layer has a relatively small addition amount in a region where the current density is relatively large in the power generation surface, and the current density is relatively small. A relatively large addition amount is set in a small region.

  In the present invention, an electrolyte may be added to the power generation surface of the gas diffusion layer together with carbon having a lower crystallinity than the carbon of the anode catalyst layer.

  According to the present invention, it is possible to suppress carbon oxidation of the anode catalyst layer while suppressing a decrease in strength of the gas diffusion layer.

It is sectional drawing of a fuel battery cell. It is a partial expansion perspective view of a gas diffusion sheet and a separator. It is addition explanatory drawing of the low crystallinity carbon to a gas diffusion sheet. It is explanatory drawing of addition of low crystallinity carbon and electrolyte to a gas diffusion sheet. It is a top view of a gas diffusion sheet. It is another partial expansion perspective view of a gas diffusion sheet and a separator. It is another top view of a gas diffusion sheet. It is explanatory drawing which shows the current density distribution of an electric power generation surface. It is area | region explanatory drawing in a large current density. It is area | region explanatory drawing in a small current density.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below is merely an example, and the present invention is not limited to the following embodiment.

1. Basic Principle The basic principle in this embodiment is that a catalyst having a lower crystallinity than that of the catalyst layer is added to the power generation surface of the gas diffusion layer, and the low crystallinity carbon is sacrificed and oxidized. Based on the technology for suppressing the oxidation of the layer, the formation position and the size of the region to which the low crystallinity carbon is added, that is, the region to be sacrificial oxidized are adjusted.

  The sacrificial oxidation of carbon with low crystallinity added to the gas diffusion layer can suppress the oxidation of carbon in the catalyst layer, but at the same time the strength of the gas diffusion layer decreases or the gas diffusibility decreases due to the sacrificial oxidation. There is a risk.

  On the other hand, the fuel battery cell is configured by sandwiching a membrane electrode assembly (MEA) between a pair of separators, and the gas diffusion layer is in contact with the separator, so that the gas diffusion layer is supported by the separator. The strength of can be reinforced. The separator has irregularities formed on the surface thereof, a hydrogen-containing gas channel as a fuel gas is formed in the concave portion, and a refrigerant channel is formed in the convex portion. Moreover, the convex part of a separator can function also as a rib.

  Therefore, when forming a region to be sacrificial oxidized in the gas diffusion layer, the rib is used as a reference and is formed so as to have a certain relationship with the rib. Specifically, by forming a region that is sacrificial oxidized so as to form a certain angle with respect to the rib, even if the strength partially decreases due to sacrificial oxidation, the strength of the gas diffusion layer is increased by the rib of the separator. Is reinforced. For example, by making the extending direction of the sacrificial oxidized region substantially perpendicular to the extending direction of the ribs, it is possible to suppress the influence of the strength reduction due to the sacrificial oxidation. Since the rib also defines the hydrogen-containing gas flow path (because the rib and the hydrogen-containing gas flow path are uneven), the hydrogen-containing gas flow path is used as a reference and a certain angle with respect to the hydrogen-containing gas flow path. It can also be said that the sacrificial oxide region is formed as it is.

  In addition, with respect to a decrease in gas diffusibility due to sacrificial oxidation, a region that is sacrificed and oxidized is formed so that the decrease in gas diffusibility does not affect the power generation performance as much as possible. The power generation performance on the power generation surface is not necessarily uniform, and the power generation performance varies due to various causes, and there are a region where the current density is relatively large and a region where the current density is relatively small. Of the region of the gas diffusion sheet corresponding to the power generation surface, in the region having a relatively large current density, the region that is sacrificial oxidized because the decrease in gas diffusibility due to sacrificial oxidation has a relatively large effect on the power generation performance. Set to a smaller value. On the other hand, in the region of the gas diffusion sheet corresponding to the power generation surface, the region having a relatively low current density has a relatively small effect on the power generation performance due to the decrease in gas diffusibility due to sacrificial oxidation. Set a larger area.

  Based on the above principle, the oxidation of the catalyst layer carbon can be suppressed by sacrificial oxidation, and the strength reduction and gas diffusibility reduction due to the sacrificial oxidation can be suppressed.

  Hereinafter, the present embodiment will be described more specifically. Note that the “crystallinity” in the present embodiment means the ratio of the crystallized portion to the whole when the polymer is partially crystallized.

2. 1st Embodiment The basic structure of the cell of the fuel cell in this embodiment is as follows. That is, a carbon fiber layer and a water repellent layer are formed on both sides of a membrane electrode assembly (MEA) formed by sandwiching an electrolyte membrane between a pair of catalyst layers (an anode catalyst layer and a cathode catalyst layer) each functioning as an electrode. And a separator is disposed so as to sandwich the membrane electrode assembly and each gas diffusion layer. The layer composed of carbon fibers is composed of an aggregate of carbon fibers, and the aggregate of carbon fibers is bonded to the water repellent layer to form a gas diffusion layer. A gas diffusion layer supplied with a hydrogen-containing gas as a fuel gas functions as an anode-side gas diffusion layer, and a gas diffusion layer supplied with an oxidant gas such as air functions as a cathode-side gas diffusion layer.

  The hydrogen-containing gas is supplied to the anode side electrode through the fuel gas flow path, and is decomposed into electrons and hydrogen ions by the action of the electrode catalyst. The electrons move through the external circuit to the cathode side electrode. On the other hand, hydrogen ions pass through the electrolyte membrane and reach the cathode electrode, and combine with oxygen and electrons that have passed through the external circuit to become reaction water. The generated water on the cathode electrode side is discharged from the cathode side.

  Next, the configuration of the present embodiment will be specifically described.

  FIG. 1 shows a cross-sectional configuration of the fuel cell in the present embodiment. The fuel cell is configured by sequentially laminating the separator 20, the separator 30, the porous body layer 34, the gas diffusion sheet 14, the MEA 10, the gas diffusion sheet 12, the separator 20, and the separator 30. In the figure, the gas diffusion sheet 12, the separator 20, and the separator 30 positioned on the lower side with respect to the MEA 10 are the anode side, and the separator 20, the separator 30, the porous body layer 34, the gas diffusion positioned on the upper side with respect to the MEA 10 The sheet 14 is the cathode side. The gas diffusion sheet 14, the MEA 10, and the gas diffusion sheet 12 are joined together.

  The separator 20 and the separator 30 have a rectangular outer shape, and a plurality of through holes are provided on the outer peripheral side to form various manifolds. The separator 20 is formed by pressing a single metal plate, and the uneven shape is inverted between the front surface and the back surface. The separator 20 has a recess 22a and a recess 22b. When the separator 20 is viewed in plan, the recesses 22a and the recesses 22b each have a comb-like pattern, and the two comb-like patterns are arranged so as to mesh with each other. High-pressure hydrogen gas is supplied to the recess 22a through a manifold formed by a through hole provided on the outer peripheral side of the anode-side separator 20. The recess 22b is connected to the anode gas exhaust system via a manifold formed by another through hole provided on the outer peripheral side of the separator 20. Accordingly, the hydrogen gas supplied to the recess 22 a flows into the adjacent recess 22 b via the gas diffusion sheet 12 in contact with the separator 20. In the course of this flow, hydrogen is supplied from the gas diffusion sheet 12 to the anode side electrode catalyst layer of the MEA 10. Further, the convex portion 24 of the separator 20 is formed to meander in the separator surface, and functions as a refrigerant flow path for flowing a coolant such as cooling water together with the separator 30.

  In such a configuration, carbon having a lower crystallinity than the catalyst layer carbon of the MEA 10 is added to the gas diffusion sheet 14 that is the gas diffusion layer on the anode side, and the carbon added to the gas diffusion sheet 14 is added to the gas diffusion sheet 14. Oxidation of the catalyst layer carbon is suppressed by selective or preferential oxidation (sacrificial oxidation). Furthermore, when carbon having a relatively low degree of crystallinity is added to the gas diffusion sheet 14, it is not added uniformly, but the flow path of the hydrogen-containing gas as the fuel gas is used as a reference, and this is constant. Add so that

  FIG. 2 is a partially enlarged perspective view of the gas diffusion sheet 12 and the separator 20 in FIG. The separator 20 includes the concave portion 22a through which the hydrogen-containing gas flows and the convex portion 24 as the refrigerant flow path as described above. Then, low crystallinity carbon is added to the gas diffusion sheet 12 in a direction substantially perpendicular to the extending direction of the recess 22a through which the hydrogen-containing gas flows. In the figure, a striped region 50 formed in the gas diffusion sheet 12 indicates a region to which low crystallinity carbon is added.

  The sacrificial oxidation of carbon having a low crystallinity can suppress the oxidation of carbon in the catalyst layer. However, as the sacrificial oxidation proceeds, the strength of the gas diffusion sheet 12 may be reduced. By adding carbon substantially perpendicular to the extending direction of 22a, even if the strength of the gas diffusion sheet 12 is partially reduced, the convex portion 24 of the separator 20 functions as a rib. Therefore, a decrease in strength occurs in a substantially vertical direction, so that a decrease in the overall strength of the gas diffusion sheet 12 can be suppressed.

  FIG. 3 schematically shows the region 50. The gas diffusion sheet 12 includes carbon fibers 12a and a binder 12b that binds the carbon fibers 12a, and low-crystallinity carbon 12c is added to the binder 12b as a sacrificial agent. When Vulcan (Vulcan) is used as the catalyst layer carbon, for example, Ketjen Black (Ketjen Black) can be used as the carbon having a relatively low crystallinity.

In the present embodiment, the low crystallinity carbon is relatively added to the gas diffusion sheet 12, but in addition to the low crystallinity carbon, the gas diffusion sheet 12 may contain an electrolyte. By containing electrolyte, at the time of hydrogen shortage of the anode,
C + H ₂ O → CO ₂ + 4H + 4e ⁻
In the gas diffusion sheet 12.

  FIG. 4 shows a schematic diagram of the region 50 in this case. The gas diffusion sheet 12 includes carbon fibers 12a and a binder 12b that binds the carbon fibers 12a, and further coats the carbon fibers 12a with a mixture of carbon 12c having a low crystallinity and an electrolyte 12d. Ketjen Black (Ketjen Black) can be used as the low crystallinity carbon 12c, and ionomers such as Nafion (registered trademark) (Nafion) can be used as the electrolyte 12d.

  As described above, in this embodiment, the low crystallinity carbon added to the gas diffusion sheet 12 or the mixture of the low crystallinity carbon and the electrolyte is striped so as to be substantially perpendicular to the flow path of the hydrogen-containing gas. By forming in a shape, the strength reduction of the gas diffusion sheet 12 due to sacrificial oxidation can be suppressed. Here, “substantially vertical” does not necessarily require vertical in a strict sense, but means that the angle formed between the hydrogen-containing gas flow path and the stripe-shaped region 50 may be close to 90 degrees. To do. Furthermore, the angle formed between the hydrogen-containing gas flow path and the stripe-shaped region 50 does not necessarily have to be substantially vertical, and may be a certain angle rather than parallel.

  FIG. 5 shows an example of forming the stripe region 50. FIG. 5A shows an angle θ formed between the hydrogen-containing gas flow path and the stripe-shaped region 50, that is, an angle θ formed between the extending direction of the hydrogen-containing gas flow path and the extending direction of the stripe-shaped region 50. Shows the case of 90 degrees. FIG. 5B shows a case where the angle θ formed by the hydrogen-containing gas flow path and the stripe-shaped region 50 is approximately 45 degrees. Generally, in order to suppress a decrease in strength of the gas diffusion sheet 12 due to sacrificial oxidation, the angle θ is preferably 45 degrees or more and 90 degrees or less, and more preferably 60 degrees or more and 90 degrees or less.

3. Second Embodiment FIG. 6 is a partially enlarged perspective view of the gas diffusion sheet 12 and the separator 20 in the present embodiment. In the present embodiment, the regions 50, that is, the regions 50 to which sacrificial oxidation is performed by adding low crystallinity carbon or a mixture of low crystallinity carbon and an electrolyte, are scattered in the form of dots rather than stripes. Further, the region 50 is scattered in a region of the gas diffusion sheet 12 that contacts the convex portion 24 of the separator 20.

  FIG. 7 shows a plan view of the gas diffusion sheet 12. The region 50 is not formed in a region corresponding to the concave portion 22a that is a hydrogen-containing gas flow path, but is scattered only in a region that faces (contacts) the convex portion 24 that is a refrigerant flow path. The convex portion 24 can function as a rib. By selectively forming the region 50 in the region facing the rib, the rib 24 can be reinforced by the rib even if the strength is partially reduced due to sacrificial oxidation.

  In addition, the sacrificial oxidation may cause not only a decrease in strength but also a decrease in gas diffusivity. However, since the convex portion 24 is a refrigerant flow path, even if a decrease in gas diffusibility due to sacrificial oxidation occurs, the power generation performance Can be suppressed.

4). Third Embodiment In the second embodiment, the gas diffusion sheet 12 is scattered in the region that is in contact with the convex portion 24 of the separator 20 with substantially the same size, but the size of each region 50 is not necessarily the same. There is no need to change the size. In the present embodiment, a case where the size of the region 50 formed in a scattered manner is changed will be described.

  FIG. 8 schematically shows the power generation performance distribution in the power generation plane of the fuel battery cell. The power generation performance is desirably uniform over the entire power generation surface, but in reality, the hydrogen-containing gas flow rate and the surface pressure distribution are not uniform and vary. Therefore, for example, as schematically shown in FIG. 8, there are a region having a relatively high current density and a region having a relatively low current density. Therefore, in response to this power generation performance distribution in the power generation plane, in the gas diffusion sheet 12, the area of the region 50 is reduced in a region where the current density is relatively large in order to suppress a decrease in gas diffusibility due to sacrificial oxidation. On the other hand, in the region where the current density is relatively small, the decrease in gas diffusibility due to sacrificial oxidation has a relatively small effect, so the area of the region 50 is increased.

  In FIG. 8, the power generation surface is divided into four regions and the relative current density is shown, but it goes without saying that the power generation surface may be further divided. The applicant of the present application divides the power generation plane into 54 sections, measures the average current density in each divided area, and confirms that there are relatively large areas and small areas.

  FIG. 9 shows the arrangement of the regions 50 in the region of the gas diffusion sheet 12 where the current density is relatively large. In the gas diffusion sheet 12, the regions 50 are scattered in the form of dots in the region where the convex portions 24 of the separator 20 abut. The area of the region 50 is relatively small.

  On the other hand, FIG. 10 shows the arrangement of the regions 50 in the region of the gas diffusion sheet 12 where the current density is relatively small. Similarly to FIG. 9, in the gas diffusion sheet 12, the regions 50 are scattered in a dot shape in the region where the convex portions 24 of the separator 20 abut. However, the area of the region 50 is relatively larger than that of FIG.

  In this way, by reducing the area of the sacrificial oxidized region 50 in a region where the current density is relatively high, and relatively increasing the area of the region 50 in a region where the current density is relatively low, While suppressing oxidation of catalyst layer carbon, the strength reduction of the gas diffusion sheet 12 accompanying sacrificial oxidation can be suppressed, and the reduction in power generation performance can be suppressed.

5. Modifications While the embodiment of the present invention has been described above, other modifications are possible.

  For example, in the first embodiment, the stripe-shaped region 50 is formed so as to be substantially perpendicular to the hydrogen-containing gas flow path. However, in the gas diffusion sheet 12, the portions other than the stripe-shaped region 50 have a low crystallinity. In addition to the case where carbon or a mixture of low crystallinity carbon and electrolyte is not added at all, it may be added at a density relatively lower than that of the region 50. The same applies to the second embodiment and the third embodiment.

  In the third embodiment, the planar shape of the region 50 is shown as a point shape, but this is only a schematic explanation, and the planar shape of the region 50 is an arbitrary one including a circle, a rectangle, and a polygon. It may be a shape.

  In the third embodiment, the area of the sacrificial oxidized region 50 is relatively small in the region where the current density is relatively high, and the area of the region 50 is relatively large in the region where the current density is relatively small. Although it is set, the amount of low crystallinity carbon added may be reduced in a region where the current density is relatively large, and the amount of low crystallinity carbon added may be increased in a region where the current density is relatively small. . That is, at least one of the size and density of the region 50 may be adaptively adjusted according to the current density (or the power generation performance).

Furthermore, in this embodiment, low crystallinity carbon or a mixture of low crystallinity carbon and an electrolyte is selectively added to a specific position of the diffusion sheet 12, but the low crystallinity carbon is substantially uniformly distributed. In addition to being added to the electrolyte 12, an electrolyte may be added to a specific position of the diffusion sheet 12. in short,
(1) Selectively add low crystallinity carbon to the gas diffusion sheet 12 (2) Selectively add low crystallinity carbon and an electrolyte to the gas diffusion sheet 12 (3) Add to the gas diffusion sheet 12 Any method of adding the low crystallinity carbon substantially uniformly and selectively adding the electrolyte can be used. In the case of (2), the low crystallinity carbon and the electrolyte are contained only in the region 50 as the sacrificial oxidation region, and in the case of (3), the low crystallinity carbon is contained not only in the region 50 but also in other regions ( Note that there is a difference in the electrolyte (area 50 only). In the case of (3), the sacrificial oxidation region is a region where an electrolyte is selectively added, and sacrificial oxidation proceeds preferentially as compared with other regions.

  10 MEA (membrane electrode assembly), 12, 14 Gas diffusion sheet, 20, 30 Separator, 22a, 22b Concavity, 24 Convex, 50 regions (sacrificial oxidation region).

Claims (8)

A fuel cell,
An anode catalyst layer;
A gas diffusion layer formed adjacent to the anode catalyst layer and diffusing a hydrogen-containing gas to supply the anode catalyst layer;
A separator formed adjacent to the gas diffusion layer and supplying the hydrogen-containing gas to the gas diffusion layer;
With
The separator has irregularities formed on the surface, the hydrogen-containing gas flow path is formed in the concave portion and the refrigerant flow path is formed in the convex portion,
In the power generation surface of the gas diffusion layer, carbon having a lower crystallinity than the carbon of the anode catalyst layer is added to function as a sacrificial oxidation region, and
The fuel cell, wherein the sacrificial oxidation region of the gas diffusion layer is formed at a certain angle with respect to an extending direction of the hydrogen-containing gas flow path. The fuel cell according to claim 1, wherein
The fuel cell, wherein the sacrificial oxidation region of the gas diffusion layer is formed to be substantially perpendicular to the extending direction of the hydrogen-containing gas flow path. A fuel cell,
An anode catalyst layer;
A gas diffusion layer formed adjacent to the anode catalyst layer and diffusing a hydrogen-containing gas to supply the anode catalyst layer;
A separator formed adjacent to the gas diffusion layer and supplying the hydrogen-containing gas to the gas diffusion layer;
With
The separator has irregularities formed on the surface, the hydrogen-containing gas flow path is formed in the concave portion and the refrigerant flow path is formed in the convex portion,
In the power generation surface of the gas diffusion layer, carbon having a lower crystallinity than the carbon of the anode catalyst layer is added to function as a sacrificial oxidation region, and
The sacrificial oxidation region of the gas diffusion layer is formed in a region facing the convex portion. The fuel cell according to claim 3, wherein
The sacrificial oxidation region of the gas diffusion layer is formed to have a relatively small area in a region having a relatively large current density and a relatively large area in a region having a relatively small current density. A fuel cell characterized in that The fuel cell according to claim 3, wherein
The sacrificial oxidation region of the gas diffusion layer is set to have a relatively small addition amount in a region having a relatively large current density and a relatively large addition amount in a region having a relatively small current density. A fuel cell characterized in that The fuel cell according to any one of claims 1 to 5,
An electrolyte is added to the power generation surface of the gas diffusion layer together with carbon having a crystallinity lower than that of the carbon of the anode catalyst layer. The fuel cell according to claim 6, wherein
The low-crystallinity carbon and the electrolyte are selectively added in the power generation surface of the gas diffusion layer. The fuel cell according to claim 6, wherein
The low crystallinity carbon is added substantially uniformly in the power generation surface of the gas diffusion layer, and the electrolyte is selectively added in the power generation surface of the gas diffusion layer. Fuel cell.

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