Electrochemical cell

Abstract

An electrolytic cell (10) is provided with a support body (11), a hydrogen electrode active layer (12), an electrolyte layer (13), and an oxygen electrode layer (15). The support body (11) has a hydrogen electrode current collector layer (20), and a first beam part (31) and a second beam part (32) embedded in the hydrogen electrode current collector layer (20). The hydrogen electrode active layer (12) includes an overlap part (12a) that overlaps with the first beam part (31) and the second beam part (32) in the z-axis direction, and a non-overlap part (12b) that does not overlap with the first beam part (31) and the second beam part (32) in the z-axis direction. The average particle diameter of Ni particles contained in the overlap part (12a) is smaller than the average particle diameter of Ni particles contained in the non-overlap part (12b).

Description

Technical Field

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

Background Art

[0002] Conventionally, an electrode-supported type electrochemical cell (electrolytic cell, fuel cell cell, etc.) including an electrolyte layer disposed between two electrode layers and one of the electrode layers functioning as a support is known.

[0003] For example, Patent Document 1 discloses an anode-supported type fuel cell cell in which the thickness of the anode among the anode, cathode, and electrolyte is the largest and the anode functions as a support.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, even if the thickness of the electrode layer functioning as a support is increased, it is difficult to obtain sufficient rigidity because the electrode layer is porous. Therefore, there is a risk that the electrochemical cell may warp with the temperature increase and decrease during the reduction treatment or operation.

[0006] An object of the present invention is to provide an electrochemical cell capable of suppressing warping.

Means for Solving the Problems

[0007] The electrochemical cell according to the first aspect of the present invention includes a support, a first electrode layer, an electrolyte layer, and a second electrode layer. The first electrode layer is disposed on the support. The electrolyte layer is disposed on the first electrode layer. The second electrode layer is disposed on the opposite side of the first electrode layer with respect to the electrolyte layer. The support has a current collecting layer and a beam portion embedded in the current collecting layer. The first electrode layer includes an overlapping portion that overlaps the beam portion in the stacking direction and a non-overlapping portion that does not overlap the beam portion in the stacking direction. The average particle diameter of the Ni particles contained in the overlapping portion is smaller than the average particle diameter of the Ni particles contained in the non-overlapping portion.

[0008] The electrochemical cell according to the second aspect of the present invention pertains to the first aspect, and the first surface of the beam portion on the side opposite to the first electrode layer is covered by the current collecting layer.

[0009] The electrochemical cell according to the third aspect of the present invention pertains to the first or second aspect, and the second surface of the beam portion on the first electrode layer side is covered by the current collecting layer.

[0010] The electrochemical cell according to the fourth aspect of the present invention pertains to any one of the first to third aspects, and the support has a frame body that surrounds the side periphery of the current collecting layer and to which the beam portions are connected.

[0011] The electrochemical cell according to the fifth aspect of the present invention pertains to any one of the first to fourth aspects, and the support has a beam structure body constituted by a plurality of beam portions.

[0012] The electrochemical cell according to the sixth aspect of the present invention pertains to the fifth aspect, and the beam structure body has a lattice structure.

[0013] The electrochemical cell according to the seventh aspect of the present invention pertains to any one of the first to sixth aspects, and the porosity of the overlapping portion is larger than the porosity of the non-overlapping portion.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide an electrochemical cell capable of suppressing warping.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0016] (Configuration of Electrolytic Cell 10) Figure 1 is a cross-sectional view of the electrolytic cell 10 according to the embodiment. Figure 2 is a perspective view of the support 11 according to the embodiment. The electrolytic cell 10 is an example of the "electrochemical cell" according to the present invention.

[0017] As shown in Figure 1, the electrolytic cell 10 includes a support 11, a hydrogen electrode active layer 12, an electrolyte layer 13, a reaction prevention layer 14, and an oxygen electrode layer 15. The hydrogen electrode active layer 12 is an example of the "first electrode layer" according to the present invention. The oxygen electrode layer 15 is an example of the "second electrode layer" according to the present invention.

[0018] In the electrolytic cell 10, the support 11, the hydrogen electrode active layer 12, the electrolyte layer 13, and the oxygen electrode layer 15 are essential components, and the reaction prevention layer 14 is an optional component.

[0019] The support 11, the hydrogen electrode active layer 12, the electrolyte layer 13, the reaction prevention layer 14, and the oxygen electrode layer 15 are laminated in this order in the Z-axis direction. The Z-axis direction is a direction perpendicular to each of the X-axis direction and the Y-axis direction. The Z-axis direction is an example of the "lamination direction" according to the present invention.

[0020] [Support 11] As shown in FIGS. 1 and 2, the support 11 is formed in a plate shape. The support 11 has a first main surface P1, a second main surface P2, and a side surface P3. The first main surface P1 is electrically connected to a separator (not shown). The first main surface P1 faces the hydrogen electrode side space S1 to which the raw material gas is supplied. The second main surface P2 is provided on the opposite side of the first main surface P1 in the Z-axis direction. The second main surface P2 is connected to the hydrogen electrode active layer 12. The side surface P3 is continuous with the first main surface P1 and the second main surface P2. The side surface P3 may be perpendicular to the first main surface P1 and the second main surface P2, or may be inclined with respect to the first main surface P1 and the second main surface P2.

[0021] The thickness of the support 11 is not particularly limited, but can be, for example, 150 μm or more and 1000 μm or less. In the Z-axis direction, the thickness of the support 11 may be greater than the thicknesses of the hydrogen electrode active layer 12, the electrolyte layer 13, the reaction prevention layer 14, and the oxygen electrode layer 15, respectively.

[0022] As shown in FIGS. 1 and 2, the support 11 has a hydrogen electrode current collector layer 20, a beam structure 30, and a frame body 40. The hydrogen electrode current collector layer 20 is an example of the "current collector layer" according to the present invention.

[0023] [Hydrogen Electrode Current Collector Layer 20] The beam structure 30 is embedded in the hydrogen electrode current collector layer 20. In the present embodiment, the hydrogen electrode current collector layer 20 is partitioned into a cell shape by the beam structure 30.

[0024] The hydrogen electrode current collector layer 20 is supported by the beam structure 30. In the present embodiment, the hydrogen electrode current collector layer 20 is also supported by the frame body 40. The hydrogen electrode current collector layer 20 functions as a support for the electrolytic cell 10 together with the beam structure 30 and the frame body 40. The electrolytic cell 10 according to the present embodiment is a so-called electrode-supported type electrochemical cell.

[0025] In addition to the current collection function, the hydrogen electrode current collector layer 20 has a gas diffusion function of diffusing the raw material gas supplied to the hydrogen electrode side space S1 toward the hydrogen electrode active layer 12.

[0026] The hydrogen electrode current collector layer 20 is a porous body having electron conductivity. The hydrogen electrode current collector layer 20 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 H2 generated in the hydrogen electrode active layer 12 and CO2 contained in the raw material gas to maintain a gas composition suitable for methanation, Fischer-Tropsch (FT) synthesis, etc. The Ni contained in the hydrogen electrode current collector layer 20 basically exists in the state of metallic Ni during the operation of the electrolytic cell 10, but a part thereof may exist in the state of nickel oxide (NiO).

[0027] The hydrogen electrode current collector layer 20 may contain an ion conductive material. As the ion conductive material, yttria-stabilized zirconia (YSZ), calcia-stabilized zirconia (CSZ), scandia-stabilized zirconia (ScSZ), gadolinium-doped ceria (GDC), samarium-doped ceria (SDC), and a mixed material obtained by combining two or more of these can be used.

[0028] The porosity of the hydrogen electrode current collector layer 20 is not particularly limited, but can be, for example, 20% or more and 40% or less.

[0029] The method for forming the hydrogen electrode current collector layer 20 is not particularly limited, and a firing method, a spray coating method (spraying method, aerosol deposition method, aerosol gas deposition method, powder jet deposition method, particle jet deposition method, cold spray method, etc.), a PVD method (sputtering method, pulsed laser deposition method, etc.), a CVD method, an extrusion molding method, a tape molding method, a printing lamination method, a casting method, a dry pressing method, etc. can be used.

[0030] [Beam structure 30] The beam structure 30 supports the hydrogen electrode current collector layer 20. The beam structure 30 functions as a support for the electrolytic cell 10 together with the hydrogen electrode current collector layer 20 and the frame body 40.

[0031] The beam structure 30 is embedded in the hydrogen electrode current collector layer 20. In the present embodiment, that the beam structure 30 is embedded in the hydrogen electrode current collector layer 20 means that at least a part of the beam structure 30 is buried in the hydrogen electrode current collector layer 20.

[0032] The beam structure 30 has a first surface Q1 and a second surface Q2.

[0033] The first surface Q1 is the surface of the beam structure 30 on the side opposite to the hydrogen electrode active layer 12. Specifically, the first surface Q1 is the surface of the first beam portion 31 and the second beam portion 32, which will be described later, on the side opposite to the hydrogen electrode active layer 12. In the present embodiment, the first surface Q1 is not covered by the hydrogen electrode current collector layer 20. That is, the first surface Q1 is exposed from the hydrogen electrode current collector layer 20. Therefore, in the present embodiment, the first surface Q1 forms a part of the first main surface P1 of the support 11.

[0034] The second surface Q2 is the surface of the beam structure 30 on the side of the hydrogen electrode active layer 12. Specifically, the second surface Q2 is the surface of the first beam portion 31 and the second beam portion 32, which will be described later, on the side of the hydrogen electrode active layer 12. In the present embodiment, the second surface Q2 is not covered by the hydrogen electrode current collector layer 20. That is, the second surface Q2 is exposed from the hydrogen electrode current collector layer 20. Therefore, in the present embodiment, the second surface Q2 forms a part of the second main surface P2 of the support 11 and is in direct contact with the hydrogen electrode active layer 12.

[0035] In the present embodiment, the beam structure 30 has a lattice structure in which a plurality of beam portions are arranged in a lattice pattern in the plane direction in a plan view from the Z-axis direction. The lattice structure is a structure in which a plurality of beam portions are arranged periodically in a plan view from the Z-axis direction. By the beam structure 30 having the lattice structure, the rigidity of the entire support 11 can be improved.

[0036] Note that the beam structure 30 according to the present embodiment has a square lattice structure, but the form of the lattice structure is not particularly limited, and may be, for example, a vertical lattice structure, a horizontal lattice structure, a hexagonal lattice structure, or the like.

[0037] The beam structure 30 can be composed of forsterite (Mg2SiO4), magnesium silicate (MgSiO3), zirconia (including partially stabilized zirconia), magnesia (MgO), magnesia alumina spinel (MgAl2O4), and a mixed material combining two or more of these.

[0038] The porosity of the beam structure 30 may be lower than that of the hydrogen electrode current collector layer 20. The porosity of the beam structure 30 can be, for example, 0.1% or more and 15% or less. The porosity of the beam structure 30 is preferably 5% or less. By improving the strength of the beam structure 30, the rigidity of the entire support 11 can be improved.

[0039] The electron conductivity of the beam structure 30 may be lower than that of the hydrogen electrode current collector layer 20. The beam structure 30 may have electron insulation. The electron conductivity of the beam structure 30 is not particularly limited, but can be 0.1 S / m or less.

[0040] As shown in FIG. 2, the beam structure 30 is composed of a plurality of beams. In the present embodiment, the beam structure 30 is composed of four first beam portions 31 and four second beam portions 32.

[0041] Each of the first beam portion 31 and the second beam portion 32 is embedded in the hydrogen electrode current collector layer 20. In the present embodiment, the first beam portion 31 being embedded in the hydrogen electrode current collector layer 20 means that at least a part of the first beam portion 31 is buried in the hydrogen electrode current collector layer 20. Similarly, the second beam portion 32 being embedded in the hydrogen electrode current collector layer 20 means that at least a part of the second beam portion 32 is buried in the hydrogen electrode current collector layer 20.

[0042] Each of the first beam portion 31 and the second beam portion 32 is formed in a columnar shape. Each of the first beam portion 31 and the second beam portion 32 extends along a plane direction perpendicular to the Z-axis direction (lamination direction). In the present embodiment, the first beam portion 31 extends along the Y-axis direction, and the second beam portion 32 extends along the X-axis direction. Therefore, in a plan view from the Z-axis direction, the angle formed by the second beam portion 32 with respect to the first beam portion 31 is 90 degrees. However, the angle formed by the second beam portion 32 with respect to the first beam portion 31 may be less than 90 degrees.

[0043] Both ends of the first beam portion 31 in the Y-axis direction are connected to the frame body 40. The first beam portion 31 may be integrally formed with the frame body 40. Both ends of the second beam portion 32 in the X-axis direction are connected to the frame body 40. The second beam portion 32 may be integrally formed with the frame body 40.

[0044] Note that the beam structure 30 according to the present embodiment has four of each of the first beam portion 31 and the second beam portion 32, but the number of each of the first beam portion 31 and the second beam portion 32 is not particularly limited and may be one or more. Further, the beam structure 30 may have only one of the first beam portion 31 and the second beam portion 32.

[0045] The method for forming the beam structure 30 is not particularly limited, and an extrusion molding method, a tape molding method, a printing lamination method, a casting method, a dry pressing method, or the like can be used.

[0046] As described above, since the support 11 has at least one of the first beam portion 31 and the second beam portion 32, the rigidity of the electrolytic cell 10 can be improved, and thus warping of the electrolytic cell 10 due to temperature rise and fall during the reduction treatment or operation can be suppressed.

[0047] [Frame body 40] The frame body 40 is formed in a frame shape. The frame body 40 surrounds the side peripheries of the hydrogen electrode current collector layer 20 and the beam structure 30. The side peripheries of the hydrogen electrode current collector layer 20 and the beam structure 30 mean the peripheries of the side surfaces formed along the thickness direction. The frame body 40 functions as a support of the electrolytic cell 10 together with the hydrogen electrode current collector layer 20 and the beam structure 30. In the present embodiment, the frame body 40 covers the entire side surface of the hydrogen electrode current collector layer 20.

[0048] In the present embodiment, as shown in FIG. 2, the planar shape of the frame body 40 is rectangular, but it may be circular, elliptical, a polygon with three or more sides, etc. according to the planar shape of the hydrogen electrode current collector layer 20.

[0049] The frame body 40 is connected to the beam structure 30. The frame body 40 may be integrally formed with the beam structure 30.

[0050] The frame body 40 can be composed of forsterite, magnesium silicate, zirconia, magnesia, magnesia alumina spinel, and a mixed material obtained by combining two or more of these.

[0051] The porosity of the frame body 40 may be lower than that of the hydrogen electrode current collector layer 20. The porosity of the frame body 40 can be, for example, 0.1% or more and 15% or less. The porosity of the frame body 40 is preferably 5% or less. Thereby, gas sealing property can be imparted to the frame body 40, so that it is possible to suppress the raw material gas from passing through the frame body 40 and returning to the hydrogen electrode side space S1 from the hydrogen electrode side space S1 toward the hydrogen electrode active layer 12. Therefore, the gas supply efficiency from the hydrogen electrode side space S1 to the hydrogen electrode active layer 12 can be improved.

[0052] The electronic conductivity of the frame body 40 may be lower than that of the hydrogen electrode current collector layer 20. The frame body 40 may have electronic insulation. The electronic conductivity of the frame body 40 is not particularly limited, but can be 0.1 S / m or less.

[0053] The forming method of the frame body 40 is not particularly limited, and an extrusion molding method, a tape molding method, a printing lamination method, a casting method, a dry pressing method, etc. can be used.

[0054] [Hydrogen electrode active layer 12] The hydrogen electrode active layer 12 functions as a cathode. The hydrogen electrode active layer 12 is disposed on the support 11. The hydrogen electrode active layer 12 is covered by the electrolyte layer 13.

[0055] The raw material gas is supplied to the hydrogen electrode active layer 12 mainly through the hydrogen electrode current collector layer 20 in the support 11. In the present embodiment, the raw material gas contains at least H2O.

[0056] When the raw material gas contains only H2O, the hydrogen electrode active layer 12 generates H2 from the raw material gas according to the electrochemical reaction of water electrolysis represented by the following formula (1). ·Hydrogen electrode active layer 12: H2O + 2e - →H2 + O 2- ···(1)

[0057] When the raw material gas contains CO2 in addition to H2O, the hydrogen electrode active layer 12 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. ·Hydrogen electrode active layer 12: 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)

[0058] The hydrogen electrode active layer 12 is a porous body having electron conductivity. The hydrogen electrode active layer 12 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 a gas composition suitable for methanation or Fischer-Tropsch (FT) synthesis. The Ni contained in the hydrogen electrode active layer 12 basically exists in the state of metallic Ni during the operation of the electrolytic cell 10, but a part thereof may exist in the state of nickel oxide (NiO).

[0059] The hydrogen electrode active layer 12 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, and a mixed material obtained by combining two or more of these can be used.

[0060] The thickness of the hydrogen electrode active layer 12 is not particularly limited, but can be, for example, 5 μm or more and 50 μm or less.

[0061] The method for forming the hydrogen electrode active layer 12 is not particularly limited, and a firing method, a spray coating method (spraying method, aerosol deposition method, aerosol gas deposition method, powder jet deposition method, particle jet deposition method, cold spray method, etc.), a PVD method (sputtering method, pulsed laser deposition method, etc.), a CVD method, an extrusion molding method, a tape molding method, a printing lamination method, a casting method, a dry pressing method, etc. can be used.

[0062] As shown in FIG. 1, the hydrogen electrode active layer 12 includes an overlapping portion 12a and a non-overlapping portion 12b.

[0063] The overlapping portion 12a is a region in the Z-axis direction (lamination direction) of the hydrogen electrode active layer 12 that overlaps with the first beam part 31 or the second beam part 32 of the beam structure 30. In the plane direction perpendicular to the Z-axis direction, the position of the overlapping portion 12a corresponds to the position of the first beam part 31 or the second beam part 32 of the beam structure 30. In the present embodiment, the overlapping portion 12a is in direct contact with the second surface Q2 of the beam structure 30.

[0064] The non-overlapping portion 12b is a region in the Z-axis direction (lamination direction) of the hydrogen electrode active layer 12 that does not overlap with the first beam part 31 or the second beam part 32 of the beam structure 30. In the plane direction perpendicular to the Z-axis direction, the position of the non-overlapping portion 12b is away from the position of the first beam part 31 or the second beam part 32 of the beam structure 30. The non-overlapping portion 12b does not contact the second surface Q2 of the beam structure 30.

[0065] Here, as described above, by having the support 11 have at least one of the first beam part 31 and the second beam part 32, warping of the electrolytic cell 10 can be suppressed. However, the raw material gas flowing from the hydrogen electrode side space S1 toward the hydrogen electrode active layer 12 is obstructed by the first beam part 31 or the second beam part 32. Therefore, the raw material gas is likely to be supplied to the non-overlapping portion 12b, while it is relatively difficult to supply the raw material gas to the overlapping portion 12a. For this reason, an electrode reaction hardly occurs in the overlapping portion 12a, and the overall performance deteriorates.

[0066] Therefore, in the present embodiment, the average particle diameter of the Ni particles contained in the overlapping portion 12a is made smaller than the average particle diameter of the Ni particles contained in the non-overlapping portion 12b. Thereby, the electrode activity of the Ni particles is improved, and the electrode activity in the overlapping portion 12a can be increased compared to the electrode activity in the non-overlapping portion 12b, so that a difference in the electrode reaction between the overlapping portion 12a and the non-overlapping portion 12b can be suppressed. As a result, the electrode reaction of the hydrogen electrode active layer 12 can be homogenized in the plane direction.

[0067] The average particle size of the Ni particles contained in the overlapping portion 12a is not particularly limited, but can be 3 μm or more and 10 μm or less. The average particle size of the Ni particles contained in the non-overlapping portion 12b is not particularly limited, but can be 2.4 μm or more and 8 μm or less.

[0068] The average particle size of the Ni particles contained in each of the overlapping portion 12a and the non-overlapping portion 12b is calculated by the following method. First, a cross-section along the thickness direction of the hydrogen electrode active layer 12 is exposed. Next, using an SEM device (manufactured by JEOL Ltd., FE-SEM JSM-7900F) and an EDS device (JED-2300) attached to the SEM device, a compositional mapping image of Ni on the cross-section is acquired at a magnification of 5000 to 10000 times. Next, using image analysis software Image-Pro manufactured by MEDIACYBERNETICS, the Ni particle portion is distinguished in the compositional mapping image of Ni by performing binarization processing in image analysis. Next, the diameter of a circle having the same area as the area of each Ni particle in the binarized image is defined as the particle size of each Ni particle. The average particle size of the Ni particles contained in the overlapping portion 12a is calculated by arithmetically averaging the particle sizes of 10 Ni particles randomly selected from 5 fields of view of the overlapping portion 12a. Similarly, the average particle size of the Ni particles contained in the non-overlapping portion 12b is calculated by arithmetically averaging the particle sizes of 10 Ni particles randomly selected from 1 field of view of the non-overlapping portion 12b.

[0069] The content of Ni in the overlapping portion 12a is not particularly limited, but can be 20 vol% or more and 50 vol% or less. The content of Ni in the non-overlapping portion 12b is not particularly limited, but can be 20 vol% or more and 50 vol% or less.

[0070] The porosity of the overlapping portion 12a is preferably larger than the porosity of the non-overlapping portion 12b. Thereby, since the gas diffusibility in the overlapping portion 12a where the raw material gas is less likely to be supplied is improved compared to the non-overlapping portion 12b where the raw material gas is easily supplied from the hydrogen electrode current collector layer 20, the electrode reaction in the overlapping portion 12a can be improved.

[0071] The porosity of the overlapping portion 12a is not particularly limited, but can be, for example, 25% or more and 45% or less. The porosity of the non-overlapping portion 12b is not particularly limited, but can be, for example, 20% or more and 40% or less.

[0072] The porosity of each of the overlapping portion 12a and the non-overlapping portion 12b is calculated by the following method. First, a cross-section along the thickness direction of the hydrogen electrode active layer 12 is exposed. Next, using the above SEM device, backscattered electron images of the cross-sections of the overlapping portion 12a and the non-overlapping portion 12b are acquired at a magnification of 10,000 times. Next, using image analysis software HALCON manufactured by MVTec, the portions displayed in black (corresponding to pores) in the backscattered electron images are distinguished. Then, the porosity of the overlapping portion 12a is calculated by dividing the total area of the pores by the total area of the backscattered electron image of the overlapping portion 12a. Similarly, the porosity of the non-overlapping portion 12b is calculated by dividing the total area of the pores by the total area of the backscattered electron image of the non-overlapping portion 12b.

[0073] [Electrolyte layer 13] The electrolyte layer 13 is disposed between the hydrogen electrode active layer 12 and the oxygen electrode layer 15. In this embodiment, since a reaction prevention layer 14 is disposed between the electrolyte layer 13 and the oxygen electrode layer 15, the electrolyte layer 13 is disposed between the hydrogen electrode active layer 12 and the reaction prevention layer 14 and is connected to each of the hydrogen electrode active layer 12 and the reaction prevention layer 14.

[0074] The electrolyte layer 13 covers the hydrogen electrode active layer 12. As shown in FIG. 1, it is preferable that the electrolyte layer 13 covers the entire surface of the hydrogen electrode active layer 12.

[0075] The electrolyte layer 13 has a function of transmitting O 2- generated in the hydrogen electrode active layer 12 to the oxygen electrode layer 15 side. The electrolyte layer 13 is a dense body having ionic conductivity and no electronic conductivity. The electrolyte layer 13 can be composed of, for example, YSZ, GDC, ScSZ, SDC, lanthanum gallate (LSGM), etc.

[0076] The porosity of the electrolyte layer 13 is not particularly limited, but can be, for example, 0.1% or more and 7% or less. The thickness of the electrolyte layer 13 is not particularly limited, but can be, for example, 1 μm or more and 100 μm or less.

[0077] The method for forming the electrolyte layer 13 is not particularly limited, and a firing method, a spray coating method, a PVD method, a CVD method, etc. can be used.

[0078] [Reaction prevention layer 14] The reaction prevention layer 14 is disposed between the electrolyte layer 13 and the oxygen electrode layer 15. The reaction prevention layer 14 is disposed on the opposite side of the hydrogen electrode active layer 12 with respect to the electrolyte layer 13. The reaction prevention layer 14 suppresses the formation of a layer with high electrical resistance due to the reaction of the constituent elements of the electrolyte layer 13 with the constituent elements of the oxygen electrode layer 15.

[0079] The reaction prevention layer 14 is composed of an ion conductive material. The reaction prevention layer 14 can be composed of GDC, SDC, etc.

[0080] The porosity of the reaction prevention layer 14 is not particularly limited, but can be, for example, 0.1% or more and 50% or less. The thickness of the reaction prevention layer 14 is not particularly limited, but can be, for example, 1 μm or more and 50 μm or less.

[0081] The method for forming the reaction prevention layer 14 is not particularly limited, and a firing method, a spray coating method, a PVD method, a CVD method, etc. can be used.

[0082] [Oxygen electrode layer 15] The oxygen electrode layer 15 functions as an anode. The oxygen electrode layer 15 is disposed on the opposite side of the hydrogen electrode active layer 12 with respect to the electrolyte layer 13. In the present embodiment, since the reaction prevention layer 14 is disposed between the electrolyte layer 13 and the oxygen electrode layer 15, the oxygen electrode layer 15 is connected to the reaction prevention layer 14. When the reaction prevention layer 14 is not disposed between the electrolyte layer 13 and the oxygen electrode layer 15, the oxygen electrode layer 15 is connected to the electrolyte layer 13.

[0083] The oxygen electrode layer 15 generates O2 from O transmitted from the hydrogen electrode active layer 12 through the electrolyte layer 13 according to the chemical reaction of the following formula (5). The O2 generated in the oxygen electrode layer 15 is released into the oxygen electrode side space S2. 2- The oxygen electrode layer 15 generates O2 from O transmitted from the hydrogen electrode active layer 12 through the electrolyte layer 13 according to the chemical reaction of the following formula (5). The O2 generated in the oxygen electrode layer 15 is released into the oxygen electrode side space S2. · Oxygen electrode layer 15: 2O 2- → O2 + 4e - ···(5)

[0084] The oxygen electrode layer 15 is a porous body having ion conductivity and electron conductivity. The oxygen electrode layer 15 can be composed of a composite material of one or more of, for example, (La, Sr)(Co, Fe)O3, (La, Sr)FeO3, La(Ni, Fe)O3, (La, Sr)CoO3, and (Sm, Sr)CoO3 and an ion conductive material (such as GDC).

[0085] The porosity of the oxygen electrode layer 15 is not particularly limited, but can be, for example, 20% or more and 60% or less. The thickness of the oxygen electrode layer 15 is not particularly limited, but can be, for example, 1 μm or more and 100 μm or less.

[0086] The method for forming the oxygen electrode layer 15 is not particularly limited, and a firing method, a spray coating method, a PVD method, a CVD method, etc. can be used.

[0087] (Modification of the embodiment) As described above, the embodiments of the present invention have been described, but the present invention is not limited to these, and various changes can be made without departing from the spirit of the present invention.

[0088] [Modification 1] In the above embodiment, the first surface Q1 of the beam structure 30 (specifically, the first and second beam portions 31 and 32) is not covered by the hydrogen electrode current collector layer 20. However, as shown in FIG. 3, it may be covered by the hydrogen electrode current collector layer 20. As a result, an outer layered portion 20a in which a part of the hydrogen electrode current collector layer 20 is formed in a layered manner is formed on the opposite side of the hydrogen electrode active layer 12 with respect to the beam structure 30. Thus, it is possible to suppress the inhibition of the electron flow between the hydrogen electrode current collector layer 20 and the separator (not shown) by the beam structure 30.

[0089] [Modification Example 2] In the above embodiment, the second surface Q2 of the beam structure 30 (specifically, the first and second beam portions 31 and 32) is not covered by the hydrogen electrode current collector layer 20 and is in direct contact with the hydrogen electrode active layer 12 (specifically, the overlapping portion 12a). However, as shown in FIG. 4, it may be covered by the hydrogen electrode current collector layer 20. As a result, an inner layered portion 20b in which a part of the hydrogen electrode current collector layer 20 is formed in a layered manner is formed between the beam structure 30 and the hydrogen electrode active layer 12. Therefore, the gas diffusion function from the hydrogen electrode current collector layer 20 to the hydrogen electrode active layer 12 can be improved.

[0090] [Modification Example 3] In the above embodiment, the frame body 40 surrounds the side peripheries of the hydrogen electrode current collector layer 20 and the beam structure 30. However, it may surround the side periphery of the hydrogen electrode active layer 12, or may further surround the side periphery of the electrolyte layer 13.

[0091] [Modification Example 4] In the above embodiment, the support 11 has the frame body 40. However, it may not have the frame body 40. In this case, the hydrogen electrode current collector layer 20 and the beam structure 30 function as the support of the electrolytic cell 10.

[0092] [Modification Example 5] In the above embodiment, the hydrogen electrode active layer 12 functions as a cathode and the oxygen electrode layer 15 functions as an anode. However, the hydrogen electrode active layer 12 may function as an anode and the oxygen electrode layer 15 may function as a cathode. In this case, the constituent materials of the hydrogen electrode active layer 12 and the oxygen electrode layer 15 are interchanged, and the source gas is flowed over the outer surface of the hydrogen electrode active layer 12. Note that the hydrogen electrode current collector layer 20 will function as an oxygen electrode current collector layer, and the configuration and function of the oxygen electrode current collector layer are the same as those of the hydrogen electrode current collector layer 20 described in the above embodiment.

[0093] [Modification Example 6] In the above embodiment, the electrolytic cell 10 has been described as an example of an electrochemical cell. However, the electrochemical cell is not limited to an 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

[0094] 10 Electrolytic cell 11 Support 12 Hydrogen electrode active layer 12a Overlapping portion 12b Non-overlapping portion 13 Electrolyte layer 14 Reaction prevention layer 15 Oxygen electrode layer 20 Hydrogen electrode current collector layer 30 Beam structure 40 Frame 50 Through hole P1 First main surface of the support P2 Second main surface of the support Q1 First surface of the beam portion Q2 Second surface of the beam portion

Claims

1. A support body, a first electrode layer disposed on the support body, an electrolyte layer disposed on the first electrode layer, a second electrode layer disposed on the opposite side of the first electrode layer with respect to the electrolyte layer, characterized by comprising: the support body has a current collecting layer and a beam portion embedded in the current collecting layer, the first electrode layer includes an overlapping portion that overlaps with the beam portion in the stacking direction and a non-overlapping portion that does not overlap with the beam portion in the stacking direction, the average particle size of Ni particles contained in the overlapping portion is smaller than the average particle size of Ni particles contained in the non-overlapping portion, an electrochemical cell.

2. A first surface of the beam portion on the side opposite to the first electrode layer is covered by the current collecting layer, The electrochemical cell according to Claim 1.

3. A second surface of the beam portion on the first electrode layer side is covered by the current collecting layer, The electrochemical cell according to Claim 1.

4. The support body has a frame body that surrounds the side periphery of the current collecting layer and to which the beam portion is connected, The electrochemical cell according to Claim 1.

5. The support body has a beam structure body composed of a plurality of the beam portions, The electrochemical cell according to Claim 1.

6. The beam structure body has a lattice structure, The electrochemical cell according to Claim 5.

7. The porosity of the overlapping portion is larger than the porosity of the non-overlapping portion, The electrochemical cell according to Claim 1.

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