Electrochemical cell

Abstract

An electrolysis cell (1) comprises a metal support (10) and a cell body (20). The metal support (10) includes: a gas permeable region (10a) in which a plurality of communication holes (11) are formed; and a gas impermeable region (10b) surrounding the gas permeable region (10a). A hydrogen pole layer (6) of the cell body (20) includes: a first region (6a) formed above the gas permeable region (10a); and a second region (6b) formed above the gas impermeable region (10b). The average particle diameter of Ni contained in the second region (6b) is smaller than the average particle diameter of Ni contained in the first region (6a).

Description

Technical Field

[0001] The present invention relates to an electrochemical cell.

Background Art

[0002] Conventionally, an electrochemical cell (such as an electrolytic cell or a fuel cell) including a metal support and a cell main body disposed on the metal support has been known (see, for example, Patent Document 1).

[0003] The metal support has a gas permeation region in which a plurality of communication holes are formed and a gas non-permeation region surrounding the gas permeation region in a plan view.

[0004] The cell main body has a first electrode layer formed on the metal support, a second electrode layer, and an electrolyte layer disposed between the first electrode layer and the second electrode layer. The first electrode layer has a first region formed on the gas permeation region of the metal support and a second region formed on the gas non-permeation region of the metal support.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When an electrochemical cell is used as a stack in which a plurality of sheets are laminated, the second region of the first electrode layer is located on the side surface side of the stack. Therefore, the temperature is likely to decrease due to heat dissipation to the outside air, and it is difficult for gas to be supplied to the second region from the communication holes. Therefore, an electrode reaction hardly occurs in the second region compared to the first region, and a current distribution occurs between the first region and the second region, making the first electrode layer liable to deteriorate.

[0007] An object of the present invention is to provide an electrochemical cell capable of suppressing deterioration of the first electrode layer.

Means for Solving the Problem

[0008] The electrochemical cell according to the first aspect of the present invention includes a metal support and a cell main body. The metal support has a gas permeation region in which a plurality of communication holes are formed and a gas non-permeation region surrounding the gas permeation region in a plan view. The cell main body is disposed on the metal support. The cell main body has a first electrode layer containing Ni, a second electrode layer, and an electrolyte layer disposed between the first electrode layer and the second electrode layer. The first electrode layer has a first region formed on the gas permeation region and a second region formed on the gas non-permeation region. The average particle diameter of Ni contained in the second region is smaller than the average particle diameter of Ni contained in the first region.

[0009] The electrochemical cell according to the second aspect of the present invention pertains to the above first aspect, and the porosity of the second region is larger than the porosity of the first region.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide an electrochemical cell capable of suppressing the deterioration of the first electrode layer.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0012] (Electrolytic Cell 1) FIG. 1 is a plan view of an electrolytic cell 1 according to an embodiment. FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1. The electrolytic cell 1 is an example of the "electrochemical cell" according to the present invention.

[0013] The electrolytic cell 1 is formed in a plate shape that spreads in the X-axis direction and the Y-axis direction. In the present embodiment, the electrolytic cell 1 is formed in a rectangle that extends in the Y-axis direction in a plan view. However, the planar shape of the electrolytic cell 1 is not particularly limited, and it may be a polygon other than a rectangle, an ellipse, a circle, or the like. Note that each of the X-axis direction and the Y-axis direction is an example of a plane direction.

[0014] As shown in FIG. 2, the electrolytic cell 1 includes a metal support 10, a cell main body portion 20, and a flow path member 30.

[0015] [Metal support 10] The metal support 10 supports the cell main body portion 20. The metal support 10 is formed in a plate shape. The metal support 10 may be in a flat plate shape or a curved plate shape. The metal support 10 only needs to be able to support the electrolytic cell 1, and its thickness is not particularly limited, but for example, it can be 0.1 mm or more and 2.0 mm or less.

[0016] As shown in FIG. 2, the metal support 10 has a plurality of communication holes 11, a first main surface 12, and a second main surface 13.

[0017] Each communication hole 11 penetrates the metal support 10 from the first main surface 12 to the second main surface 13. Each communication hole 11 opens to each of the first main surface 12 and the second main surface 13. The opening of each communication hole 11 on the first main surface 12 side is covered by the hydrogen electrode layer 6. The opening of each communication hole 11 on the second main surface 13 side is connected to a flow path 30a described later.

[0018] Each communication hole 11 can be formed by machining (for example, punching), laser processing, or chemical processing (for example, etching). Further, when the metal support 10 is made of a porous metal, each communication hole 11 may be a communication hole in which the open pores of the porous metal communicate. Each communication hole 11 may be perpendicular to the first main surface 12, may not be perpendicular to the first main surface 12, or may not be linear.

[0019] The cell body 20 is joined to the first major surface 12. The flow path member 30 is joined to the second major surface 13. The first major surface 12 is provided on the side opposite to the second major surface 13.

[0020] As shown in FIG. 2, the metal support 10 has a gas permeable region 10a and a gas non-permeable region 10b. The gas permeable region 10a is a region in the metal support 10 where a plurality of communication holes 11 are formed. The gas non-permeable region 10b is a region in the metal support 10 other than the gas permeable region 10a. The gas non-permeable region 10b surrounds the gas permeable region 10a in a plan view from the Z-axis direction perpendicular to the X-axis direction and the Y-axis direction. Therefore, as shown in FIG. 2, in the cross section of the metal support 10 along the Z-axis direction, the gas non-permeable region 10b appears on both sides of the gas permeable region 10a.

[0021] As shown in FIG. 2, the boundary between the gas permeable region 10a and the gas non-permeable region 10b is defined by the openings of the first and second communication holes 11a and 11b located most outward in the X-axis direction, respectively. Specifically, the boundary between the gas permeable region 10a and the gas non-permeable region 10b is defined by the first reference line 11S and the second reference line 11T. The first reference line 11S is a straight line passing through the outermost position P1 in the X-axis direction among the openings on the first major surface 12 side of the first communication hole 11a located most outward in the X-axis direction and parallel to the Z-axis direction (perpendicular to the first major surface 12 in FIG. 2). The second reference line 11T is a straight line passing through the outermost position P2 in the X-axis direction among the openings on the first major surface 12 side of the second communication hole 11b farthest from the first supply hole 11a in the X-axis direction and parallel to the Z-axis direction (perpendicular to the first major surface 12 in FIG. 2). The region between the first reference line 11S and the second reference line 11T in the metal support 10 is the gas permeable region 10a, and the region of the metal support 10 excluding the gas permeable region 10a, that is, the regions on both sides of the gas permeable region 10a, is the gas non-permeable region 10b.

[0022] The metal support 10 is composed of a metal material. For example, the metal support 10 is composed of an alloy material containing Cr (chromium). Examples of such metal materials include Fe-Cr alloy steel (such as stainless steel) and Ni-Cr alloy steel. The content rate of Cr in the metal support 10 is not particularly limited, but can be 4 mass% or more and 30 mass% or less.

[0023] The metal support 10 may contain Ti (titanium) or Zr (zirconium). The content rate of Ti in the metal support 10 is not particularly limited, but can be 0.01 mol% or more and 1.0 mol% or less. The content rate of Al in the metal support 10 is not particularly limited, but can be 0.01 mol% or more and 0.4 mol% or less. The metal support 10 may contain Ti as TiO2 (titania) or Zr as ZrO2 (zirconia).

[0024] The metal support 10 may have an oxide film formed on its surface by oxidation of the constituent elements of the metal support 10. As the oxide film, for example, a chromium oxide film is typical. The chromium oxide film covers at least a part of the surface of the metal support 10. Further, the chromium oxide film may cover at least a part of the inner wall surface of each communication hole 11.

[0025] [Cell main body part 20] The cell main body part 20 is disposed on the metal support 10. The cell main body part 20 has a hydrogen electrode layer 6 (cathode), an electrolyte layer 7, a reaction prevention layer 8, and an oxygen electrode layer 9 (anode).

[0026] The hydrogen electrode layer 6, the electrolyte layer 7, the reaction prevention layer 8, and the oxygen electrode layer 9 are laminated in this order from the metal support 10 side in the Z-axis direction perpendicular to the X-axis direction and the Y-axis direction. The hydrogen electrode layer 6, the electrolyte layer 7, and the oxygen electrode layer 9 are essential components, and the reaction prevention layer 8 is an optional component.

[0027] [Hydrogen electrode layer 6] The hydrogen electrode layer 6 is formed on the metal support 10. The hydrogen electrode layer 6 is disposed between the metal support 10 and the electrolyte layer 7. The hydrogen electrode layer 6 is supported by the metal support 10. Specifically, the hydrogen electrode layer 6 is disposed on the first main surface 12 of the metal support 10. The hydrogen electrode layer 6 is an example of the "first electrode layer" according to the present invention.

[0028] The raw material gas is supplied to the hydrogen electrode layer 6 through each communication hole 11. The raw material gas contains at least H2O.

[0029] When the raw material gas contains only H2O, the hydrogen electrode layer 6 generates H2 from the raw material gas according to the electrochemical reaction of water electrolysis represented by the following formula (1).

[0030] · Hydrogen electrode layer 6: H2O + 2e - → H2 + O 2- ··· (1)

[0031] When the raw material gas contains CO2 in addition to H2O, the hydrogen electrode layer 6 generates H2, CO, and O from the raw material gas according to the electrochemical reactions of co-electrolysis represented by the following formulas (2), (3), and (4). 2- are generated.

[0032] · Hydrogen electrode layer 6: CO2 + H2O + 4e - → CO + H2 + 2O 2- ··· (2) · Electrochemical reaction of H2O: H2O + 2e - → H2 + O 2- ··· (3) · Electrochemical reaction of CO2: CO2 + 2e - → CO + O 2- ··· (4)

[0033] The hydrogen electrode layer 6 is a porous body having electron conductivity. The hydrogen electrode layer 6 contains nickel (Ni). In the case of co-electrolysis, Ni functions as an electron conductive material and also functions as a thermal catalyst that promotes the thermal reaction between the generated H2 and CO2 contained in the raw material gas to maintain an appropriate gas composition for methanation and the reverse water gas shift reaction. The Ni contained in the hydrogen electrode layer 6 basically exists in the state of metallic Ni during the operation of the electrolytic cell 1, but a part thereof may exist in the state of nickel oxide (NiO).

[0034] The hydrogen electrode layer 6 may contain an ion conductive material. As the ion conductive material, YSZ, CSZ, ScSZ, GDC, SDC, (La,Sr)(Cr,Mn)O3, (La,Sr)TiO3, Sr2(Fe,Mo)2O6, (La,Sr)VO3, (La,Sr)FeO3, LDC (lanthanum-doped ceria), LSGM (lanthanum gallate), and a mixed material combining two or more of these can be used.

[0035] The content of Ni in the hydrogen electrode layer 6 is not particularly limited, but can be 20 vol% or more and 50 vol% or less. The content of Ni is calculated by the following method. First, expose the cross-section of the hydrogen electrode layer 6 along the Z-axis direction. Next, using an SEM device (manufactured by JEOL Ltd., FE-SEM JSM-7900F) and an EDS device (JED-2300) attached to the SEM device, obtain a composition mapping image of Ni in the cross-section of the hydrogen electrode layer 6 at a magnification of 5000 to 10000 times. Next, using image analysis software Image-Pro manufactured by MEDIACYBERNETICS, identify Ni particles in the composition mapping image of Ni by performing binarization processing in image analysis. Then, the content of Ni in the hydrogen electrode layer 6 is calculated by dividing the total area of Ni particles by the total area of the hydrogen electrode layer 6 (including pores) in the backscattered electron image.

[0036] The content of the ion conductive material in the hydrogen electrode layer 6 is not particularly limited, but can be 20 vol% or more and 50 vol% or less. The content of the ion conductive material is calculated by the following method. First, using the above-described SEM apparatus and EDS apparatus, a composition mapping image of the element with the largest content (hereinafter referred to as the "maximum content element") among the constituent elements of the ion conductive material in the cross section of the hydrogen electrode layer 6 is acquired at a magnification of 5000 to 10000 times. Next, using the above-described image analysis software Image-Pro, the particle portion of the maximum content element is specified in the composition mapping image of the maximum content element by performing binarization processing in image analysis. Then, the content of the ion conductive material in the hydrogen electrode layer 6 is calculated by dividing the total area of the particle portions of the maximum content element by the total area (including pores) of the entire hydrogen electrode layer 6 in the backscattered electron image.

[0037] The thickness of the hydrogen electrode layer 6 is not particularly limited, but can be, for example, 1 μm or more and 100 μm or less.

[0038] As shown in FIG. 2, the hydrogen electrode layer 6 has a first region 6a and a second region 6b. The first region 6a is a region formed on the gas permeation region 10a of the metal support 10 in the hydrogen electrode layer 6. The second region 6b is a region formed on the gas non-permeation region 10b of the metal support 10 in the hydrogen electrode layer 6. The second region 6b surrounds the first region 6a in a plan view from the Z-axis direction. Therefore, as shown in FIG. 2, in the cross section of the hydrogen electrode layer 6 along the Z-axis direction, the second region 6b appears on both sides of the first region 6a.

[0039] The boundary between the first region 6a and the second region 6b is defined by the above-described first reference line 11S and second reference line 11T. The region between the first reference line 11S and the second reference line 11T in the hydrogen electrode layer 6 is the first region 6a, and the region excluding the first region 6a in the hydrogen electrode layer 6, that is, the regions on both sides of the first region 6a is the second region 6b.

[0040] Here, since the average particle size of Ni contained in the second region 6b is smaller than the average particle size of Ni contained in the first region 6a, the activity of Ni contained in the second region 6b is higher than that of Ni contained in the first region 6a. As a result, compared with the first region 6a, a temperature drop due to heat dissipation is likely to occur, and the electrode activity in the second region 6b where it is difficult for the raw material gas to be supplied from the communication holes 11 can be improved. Therefore, the difference in electrode activity between the first region 6a and the second region 6b can be reduced, and the occurrence of a current distribution between the two can be suppressed, so that the deterioration of the hydrogen electrode layer 6 can be suppressed.

[0041] Also, conventionally, in the second region 6b, since the electrode activity decreases due to a temperature drop caused by heat dissipation, the generation rate of H2 is small and the H2O concentration tends to increase. When the H2O concentration increases, the growth rate of the oxide film on the surface of the metal support 10 increases, so that it becomes difficult for current to flow through the second region 6b and the current distribution increases. In the present embodiment, the electrode activity can be improved by reducing the average particle size of Ni in the second region 6b. As a result, since the generation rate of H2 is maintained, an increase in the current distribution can be suppressed.

[0042] Note that, unlike a fuel cell in which an exothermic reaction occurs, in the electrolytic cell 1 in which an endothermic reaction occurs, the second region 6b is likely to experience a temperature drop. Also, in the electrolytic cell 1, by reducing the average particle size of Ni, the function of Ni as a thermal catalyst can be improved. Therefore, the above-described effects are particularly effective in the electrolytic cell 1.

[0043] The average particle size of Ni contained in the first region 6a is not particularly limited, but can be 3 μm or more and 10 μm or less. The average particle size of Ni contained in the second region 6b is not particularly limited, but can be 1 μm or more and 7 μm or less.

[0044] The average particle size of Ni contained in the first region 6a is calculated by the following method. First, the cross-section of the hydrogen electrode layer 6 along the Z-axis direction is exposed. Next, using an SEM device (FE-SEM JSM-7900F manufactured by JEOL Ltd.) and an EDS device (JED-2300 attached to the SEM device), Ni mapping images at five positions that divide the first region 6a into six equal parts in the thickness direction are acquired at three locations: an arbitrary position on the first communication hole 11a, an arbitrary position on the second communication hole 11b, and the center of the first region 6a in the plane direction, at magnifications of 5000 to 10000 times. As a result, 15 Ni mapping images are acquired. Next, using image analysis software Image-Pro manufactured by MEDIACYBERNETICS, the Ni particle portions are identified in each Ni mapping image by performing binarization processing in the image analysis. As a result, 15 analysis images are acquired. Next, in each of the binarized analysis images, the diameter of a circle having the same area as the area of each Ni is acquired as the particle size of each Ni. Then, the average particle size of Ni contained in the first region 6a is calculated by arithmetically averaging the particle sizes of Ni acquired from the 15 analysis images.

[0045] In this specification, the thickness direction is a direction perpendicular to the plane direction parallel to the first main surface 12 of the metal support 10. When specifying the thickness direction, in the cross-section of the metal support 10 along the Z-axis direction, the approximate straight line of the first main surface 12 obtained by the least squares method is used.

[0046] The average particle size of Ni contained in the second region 6b is calculated by the same method as the average particle size of Ni contained in the first region 6a. However, Ni mapping images at five positions that divide the second region 6b into six equal parts in the thickness direction are acquired at two locations that divide each second region 6b located on both sides of the first region 6a into three equal parts in the plane direction. Therefore, 20 Ni mapping images are used to calculate the average particle size of Ni contained in the second region 6b. Also, the 20 Ni mapping images are acquired on the cross-section of the hydrogen electrode layer 6 used when calculating the average particle size of Ni contained in the first region 6a.

[0047] The porosity of the second region 6b is preferably greater than the porosity of the first region 6a. Thereby, since the gas diffusibility in the second region 6b where the raw material gas is less likely to be supplied from each communication hole 11 can be improved, the electrode reaction in the second region 6b can be further improved. Therefore, since the occurrence of a current distribution between the first region 6a and the second region 6b can be further suppressed, the deterioration of the first electrode layer 6 can be further suppressed.

[0048] The porosity of the first region 6a is not particularly limited, but can be 20% or more and 40% or less. The porosity of the second region 6b is not particularly limited, but can be 25% or more and 50% or less.

[0049] The porosity of the first region 6a is calculated by the following method. First, expose the cross-section of the hydrogen electrode layer 6 along the Z-axis direction. Next, using the above SEM device, obtain a backscattered electron image of the cross-section of the first region 6a at a magnification of 10,000 times. Next, using the image analysis software Image-Pro manufactured by MEDIACYBERNETICS, identify the portion (corresponding to pores) displayed in black in the backscattered electron image. Then, the porosity of the first region 6a is calculated by dividing the total area of the pores by the total area of the backscattered electron image of the first region 6a.

[0050] The porosity of the second region 6b is calculated in the same manner as the porosity of the first region 6a, by dividing the total area of the pores by the total area of the backscattered electron image of the second region 6b.

[0051] The hydrogen electrode layer 6 is produced by forming the first region 6a on the metal support 10 using the constituent material for the first region, and then forming the second region 6b so as to surround the first region 6a using the constituent material for the second region. The forming methods of the first and second regions 6a and 6b are not particularly limited, and firing methods, spray coating methods (thermal spraying methods, aerosol deposition methods, aerosol gas deposition methods, powder jet deposition methods, particle jet deposition methods, cold spray methods, etc.), PVD methods (sputtering methods, pulsed laser deposition methods, etc.), CVD methods, etc. can be used.

[0052] [Electrolyte layer 7] The electrolyte layer 7 is disposed between the hydrogen electrode layer 6 and the oxygen electrode layer 9. In this embodiment, since the reaction prevention layer 8 is disposed between the electrolyte layer 7 and the oxygen electrode layer 9, the electrolyte layer 7 is disposed between the hydrogen electrode layer 6 and the reaction prevention layer 8 and is connected to each of the hydrogen electrode layer 6 and the reaction prevention layer 8.

[0053] The electrolyte layer 7 covers the hydrogen electrode layer 6 and covers the region of the first main surface 12 of the metal support 10 that is exposed from the hydrogen electrode layer 6.

[0054] The electrolyte layer 7 transfers the O 2- generated in the hydrogen electrode layer 6 to the oxygen electrode layer 9 side. The electrolyte layer 7 is composed of a dense material having oxide ion conductivity. The electrolyte layer 7 can be composed of, for example, YSZ (yttria-stabilized zirconia, such as 8YSZ), GDC (gadolinium-doped ceria), ScSZ (scandia-stabilized zirconia), SDC (samarium-doped ceria), LSGM (lanthanum gallate), etc.

[0055] The porosity of the electrolyte layer 7 is not particularly limited, but can be, for example, 0.1% or more and 7% or less. The thickness of the electrolyte layer 7 is not particularly limited, but can be, for example, 1 μm or more and 100 μm or less.

[0056] The method for forming the electrolyte layer 7 is not particularly limited, and a firing method, a spray coating method, a PVD method, a CVD method, etc. can be used.

[0057] [Reaction prevention layer 8] The reaction prevention layer 8 is disposed between the electrolyte layer 7 and the oxygen electrode layer 9. The reaction prevention layer 8 is disposed on the opposite side of the hydrogen electrode layer 6 with respect to the electrolyte layer 7. The reaction prevention layer 8 suppresses the formation of a layer with a large electrical resistance due to the reaction of the constituent elements of the electrolyte layer 7 with the constituent elements of the oxygen electrode layer 9.

[0058] The reaction prevention layer 8 is composed of an oxide ion conductive material. The reaction prevention layer 8 can be composed of GDC, SDC, etc.

[0059] The porosity of the reaction prevention layer 8 is not particularly limited, but can be, for example, 0.1% or more and 50% or less. The thickness of the reaction prevention layer 8 is not particularly limited, but can be, for example, 1 μm or more and 50 μm or less.

[0060] The method for forming the reaction prevention layer 8 is not particularly limited, and a firing method, a spray coating method, a PVD method, a CVD method, or the like can be used.

[0061] [Oxygen electrode layer 9] The oxygen electrode layer 9 is disposed on the opposite side of the hydrogen electrode layer 6 with respect to the electrolyte layer 7. In the present embodiment, since the reaction prevention layer 8 is disposed between the electrolyte layer 7 and the oxygen electrode layer 9, the oxygen electrode layer 9 is connected to the reaction prevention layer 8. When the reaction prevention layer 8 is not disposed between the electrolyte layer 7 and the oxygen electrode layer 9, the oxygen electrode layer 9 is connected to the electrolyte layer 7. The oxygen electrode layer 9 is an example of the "second electrode layer" according to the present invention.

[0062] The oxygen electrode layer 9 generates O2 from O transmitted from the hydrogen electrode layer 6 through the electrolyte layer 7 according to the chemical reaction of the following formula (2). 2- to generate O2.

[0063] ·Oxygen electrode layer 9: 2O 2- →O2 + 4e - ···(2)

[0064] The oxygen electrode layer 9 is composed of a porous material having oxide ion conductivity and electron conductivity. The oxygen electrode layer 9 can be composed of, for example, a composite material of one or more of (La, Sr)(Co, Fe)O3, (La, Sr)FeO3, La(Ni, Fe)O3, (La, Sr)CoO3, and (Sm, Sr)CoO3 and an oxide ion conducting material (such as GDC).

[0065] The porosity of the oxygen electrode layer 9 is not particularly limited, but can be, for example, 20% or more and 60% or less. The thickness of the oxygen electrode layer 9 is not particularly limited, but can be, for example, 1 μm or more and 100 μm or less.

[0066] The method for forming the oxygen electrode layer 9 is not particularly limited, and a firing method, a spray coating method, a PVD method, a CVD method, etc. can be used.

[0067] [Flow channel member 30] The flow channel member 30 is joined to the second main surface 13 of the metal support 10. The flow channel member 30 forms a flow channel 30a between it and the metal support 10. A raw material gas is supplied to the flow channel 30a. The raw material gas supplied to the flow channel 30a is supplied to the hydrogen electrode layer 6 of the cell main body 20 through each communication hole 11 of the metal support 10.

[0068] The flow channel member 30 can be formed of, for example, an alloy material. The flow channel member 30 may be formed of the same material as the metal support 10. In this case, the flow channel member 30 may be substantially integral with the metal support 10.

[0069] The flow channel member 30 has a frame body 31 and an interconnector 32. The frame body 31 is an annular member that surrounds the side of the flow channel 30a. The frame body 31 is joined to the second main surface 13 of the metal support 10. The interconnector 32 is a plate-like member for electrically connecting an external power source or another electrolytic cell in series with the electrolytic cell 1. The interconnector 32 is joined to the frame body 31.

[0070] In the present embodiment, the frame body 31 and the interconnector 32 are separate members, but the frame body 31 and the interconnector 32 may be an integral member.

[0071] (Modification of the embodiment) As described above, the embodiments of the present invention have been explained, but the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention.

[0072] [Modification 1] A part of the hydrogen electrode layer 6 may enter each communication hole 11 of the metal support 10. However, the first region 6a of the hydrogen electrode layer 6 described in the above embodiment is a region formed on the gas permeation region 10a of the metal support 10 in the hydrogen electrode layer 6. Therefore, the region of the hydrogen electrode layer 6 that has entered the communication hole 11 is not included in the second region 6b of the hydrogen electrode layer 6.

[0073] [Modification Example 2] In the above embodiment, it was explained that in a cross-section of the hydrogen electrode layer 6, the average particle diameter of Ni contained in the second region 6b is smaller than the average particle diameter of Ni contained in the first region 6a. Such a configuration is preferably observed in all cross-sections of the hydrogen electrode layer 6, but it is sufficient if it can be observed in at least one cross-section of the hydrogen electrode layer 6. This is because if it is observed even in one cross-section, the deterioration of the hydrogen electrode layer 6 can be suppressed at least at that location.

[0074] [Modification Example 3] In the above embodiment, the electrolytic cell 1 was described as an example of the electrochemical cell, but the electrochemical cell is not limited to the electrolytic cell. An electrochemical cell is a general term for an element in which a pair of electrodes are arranged so that an electromotive force is generated from an overall oxidation-reduction reaction in order to convert electrical energy into chemical energy, and an element for converting chemical energy into electrical energy. Therefore, the electrochemical cell includes, for example, a fuel cell that uses oxide ions or protons as carriers.

Explanation of Reference Numerals

[0075] 1 Electrolytic cell 10 Metal support 11 Communication hole 12 First main surface 13 Second main surface 20 Cell main body part 6 Hydrogen electrode layer 7 Electrolyte layer 8 Reaction prevention layer 9 Oxygen electrode layer 30 Flow path member 30a Flow path

Claims

1. A metal support having a gas permeation region in which a plurality of communication holes are formed and a gas non-permeation region surrounding the gas permeation region in plan view, A cell main body portion disposed on the metal support, comprising, The cell main body portion, A first electrode layer containing Ni, A second electrode layer, An electrolyte layer disposed between the first electrode layer and the second electrode layer, having, The first electrode layer has a first region formed on the gas permeation region and a second region formed on the gas non-permeation region, The average particle diameter of Ni contained in the second region is smaller than the average particle diameter of Ni contained in the first region, An electrochemical cell.

2. The porosity of the second region is larger than the porosity of the first region, The electrochemical cell according to claim 1.

3. The first electrode layer is a hydrogen electrode that generates H ２ from a raw material gas containing O to H ２ , The electrochemical cell according to claim 1 or 2.

Images