Cell and cell stack device

Abstract

This cell comprises a solid electrolyte layer, a first porous layer, and a second porous layer. The solid electrolyte layer has a first surface and a second surface that is positioned on the opposite side of the first surface. The first porous layer is positioned on the first surface and includes a first catalyst, a first material having ion conductivity, and first pores. The second porous layer is positioned on the second surface and includes a second catalyst, a second material having ion conductivity, and second pores. The properties of the first pores are different from the properties of the second pores.

Description

Cell and cell stack device

[0001] This disclosure relates to cells and cell stacking devices.

[0002] A cylindrical cell is known that generates hydrogen by supplying carbon monoxide and water vapor to a pair of electrodes, respectively.

[0003] U.S. Patent Application Publication No. 2022 / 0372635

[0004] A cell according to one embodiment comprises a solid electrolyte layer, a first porous layer, and a second porous layer. The solid electrolyte layer has a first surface and a second surface located opposite the first surface. The first porous layer is located on the first surface and includes a first catalyst, an ion-conducting first material, and first pores. The second porous layer is located on the second surface and includes a second catalyst, an ion-conducting second material, and second pores. The properties of the first pores are different from those of the second pores.

[0005] A cell stack device according to one embodiment has a cell stack including the cells described above.

[0006] Figure 1A is a cross-sectional view showing an example of a cell according to the first embodiment. Figure 1B is a side view of an example of a cell according to the first embodiment, viewed from the first member side of the second electrode. Figure 1C is a side view of an example of a cell according to the first embodiment, viewed from the second member side of the second electrode. Figure 2A is a cross-sectional view showing an example of a cell according to the second embodiment. Figure 2B is a side view showing an example of a cell according to the second embodiment. Figure 3 is a perspective view showing an example of a cell stacking apparatus according to the embodiment.

[0007] The aforementioned cells had room for improvement in terms of performance.

[0008] Therefore, there is a need for the provision of cells and cell stacking devices that can improve performance.

[0009] Embodiments of the cell and cell stack apparatus disclosed herein will be described in detail below with reference to the attached drawings. However, this disclosure is not limited to the embodiments described below.

[0010] Furthermore, it should be noted that drawings are schematic representations, and the dimensional relationships and proportions of each element may differ from reality. Moreover, there may be discrepancies in dimensional relationships and proportions between drawings themselves.

[0011] [First Embodiment] <Cell Configuration> Figure 1A is a cross-sectional view showing an example of a cell according to the first embodiment. Figure 1B is a side view of an example of a cell according to the first embodiment, viewed from the first member side of the second electrode. Figure 1C is a side view of an example of a cell according to the first embodiment, viewed from the second member side of the second electrode. Figures 1A to 1C show enlarged views of parts of each component of the cell.

[0012] The cell 1 according to this embodiment is a hollow, flat plate type and is elongated in shape. As shown in Figure 1B, the overall shape of the cell 1 when viewed from the side may be, for example, rectangular. The length L of the cell 1 may be 5 cm to 50 cm. The length W of the cell 1, which is perpendicular to the length L, may be, for example, 1 cm to 10 cm. The overall thickness T of the cell 1 may be, for example, 1 mm to 5 mm.

[0013] As shown in Figure 1A, cell 1 comprises an element section 3. The element section 3 comprises a first electrode 5 as a first porous layer, a solid electrolyte layer 6, and a second electrode 7 as a second porous layer.

[0014] The solid electrolyte layer 6 has a first surface 61 and a second surface 62. The first surface 61 may be the inner surface of the solid electrolyte layer 6 located on the side of the flow channel 2a, which will be described later. The second surface 62 may be the outer surface of the solid electrolyte layer 6 located on the opposite side of the first surface 61.

[0015] The solid electrolyte layer 6 has oxide ion conductivity and electronic conductivity. The solid electrolyte layer 6 may include an electronically conducting phase, for example, doped lanthanum chromite, an electronically conductive metal, or a combination thereof. The solid electrolyte layer 6 may also include an ionically conducting phase, which may include a material selected from gadolinium-doped ceria, samarium-doped ceria, yttria-stabilized zirconia (YSZ), lanthanum strontium gallate magnesite (LSGM), lanthanum strontium titanate (LST), scandia-stabilized zirconia (SSZ), scandinium and cerium-doped zirconia, and combinations thereof. The doped lanthanum chromite may include strontium-doped chromium lanthanum, iron-doped chromium lanthanum, strontium and iron-doped lanthanum chromite, lanthanum calcium chromite, or a combination thereof. The electronically conductive metal may include Ni, Cu, Ag, Au, Pt, Rh, or combinations thereof.

[0016] The first electrode 5 is located on the first surface 61 of the solid electrolyte layer 6. The first electrode 5 includes a first catalyst 51, a first material 52, and a first pore 53. The first catalyst 51 may be, for example, metallic Ni or NiO.

[0017] The first material 52 is ionic conductive. The first material 52 may be yttria-stabilized zirconia (YSZ). The first material 52 may be a material selected from the group consisting of, for example, YSZ, gadolinium-doped ceria (GDC or CGO), samaria-doped ceria (SDC), scandia-stabilized zirconia (SSZ), lanthanum-strontium gallate-magnesite (LSGM), and combinations thereof.

[0018] The first pore 53 is a void located at the first electrode 5. The average pore diameter of the first pore 53 may be, for example, 3 μm or more and 7 μm or less, and particularly 4 μm or more and 6 μm or less.

[0019] The first electrode 5 may be supplied with the first gas. In other words, the first electrode 5 may be in contact with the first gas.

[0020] The second electrode 7 is located on the second surface 62 of the solid electrolyte layer 6. The second electrode 7 includes a second catalyst 71, a second material 72, and a second pore 73.

[0021] The second catalyst 71 may contain elements included in the first catalyst 51. The second catalyst 71 may contain, for example, Ni. The second catalyst 71 may be metallic Ni or NiO. The second catalyst 71 may be the same as the first catalyst 51. The second catalyst 71 may contain elements different from those of the first catalyst 51.

[0022] The second material 72 is ionic conductive. The second material 72 may contain oxides contained in the first material 52. The second material 72 may be the same as the first material 52. The second electrode 7 may contain an oxide different from that of the first material 52 as the second material 72.

[0023] The second pore 73 is a void located on the second electrode 7. The average pore diameter of the second pore 73 may be, for example, 10 μm or more and 35 μm or less, and particularly 13 μm or more and 27 μm or less.

[0024] The second electrode 7 may be supplied with a second gas having a higher water vapor content than the first gas. In other words, the second electrode 7 may be in contact with a second gas having a higher water vapor content than the first gas.

[0025] Cell 1 generates hydrogen through a water-gas shift reaction between a first gas in contact with the first electrode 5 and a second gas in contact with the second electrode 7. The first gas may contain, for example, carbon monoxide (CO). The second gas may contain, for example, water vapor (H ２ It may include O).

[0026] Cell 1 converts carbon dioxide (CO) from carbon monoxide (CO) contained in the first gas supplied to the first electrode 5. ２This generates a reaction. At this time, the polarization resistance of the catalytic reaction in the first catalyst 51 becomes the rate-limiting factor at the first electrode 5. For this reason, in order to reduce the polarization resistance of the catalytic reaction in the first catalyst 51 at the first electrode 5, it is preferable, for example, for the porosity of the first electrode 5 and / or the average pore size of the first pores 53 to be small.

[0027] Furthermore, cell 1 absorbs water vapor (H) contained in the second gas supplied to the second electrode 7. ２ O) to hydrogen (H ２ This generates a gas. At this time, the polarization resistance of gas diffusion in the second electrode 7 becomes the rate-limiting factor. For this reason, in order to reduce the polarization resistance of gas diffusion in the second electrode 7, it is preferable, for example, for the porosity of the second electrode 7 and / or the average pore diameter of the second pores 73 to be large.

[0028] In this embodiment, the properties of the first pores 53 located at the first electrode 5 differ from those of the second pores 73 located at the second electrode 7. This reduces the polarization resistance at the first electrode 5 and the second electrode 7, improving reactivity. Therefore, the performance of the cell 1 according to this embodiment is improved.

[0029] In this embodiment, the porosity of the first electrode 5 of the cell 1 may be less than that of the second electrode 7. The porosity of the first electrode 5 may be, for example, 15% or more and 35% or less, and particularly 20% or more and 30% or less. The porosity of the second electrode 7 may be, for example, 35% or more and 55% or less, and particularly 40% or more and 50% or less. When the porosity of the first electrode 5 is A (%) and the porosity of the second electrode 7 is B (%), the difference between B and A (B-A) may be, for example, 5 or more and 30 or less, particularly 10 or more and 25 or less, and even more preferably 15 or more and 20 or less.

[0030] In the cell 1 according to the present embodiment, the average pore diameter of the second pores 73 may be different from the average pore diameter of the first pores 53. In the cell 1, for example, the average pore diameter of the second pores 73 may be larger than the average pore diameter of the first pores 53. When the first gas in contact with the first electrode 5 and the second gas in contact with the second electrode 7 are different from each other, adjusting the properties of the pores located in each electrode in accordance with the properties of each gas and the reaction between each electrode and the gas in contact therewith improves the reactivity between each electrode and the gas in contact therewith. Examples of combinations of gases that the first electrode 5 and the second electrode 7 respectively come into contact with include carbon monoxide and water vapor, hydrogen and carbon dioxide, ammonia and water vapor, and the like. Among these combinations, the former is the first gas and the latter is the second gas. These gases may be mixed gases further containing, for example, hydrocarbons such as methane, oxygen, nitrogen and the like. Gases such as water vapor and ammonia are difficult to diffuse because they have relatively high viscosity at reaction temperatures, and the reaction with electrodes is rate-limited by gas diffusion. In particular, water vapor is likely to condense via capillary condensation inside a porous body such as the first electrode 5, and intermolecular interactions are likely to occur. Therefore, a gas containing a large amount of water vapor tends to have higher viscosity.

[0031] For an electrode in contact with a gas containing a large amount of such high-viscosity components, for example, having large pores, that is, having a large average pore diameter, reduces the polarization resistance that is rate-limited by gas diffusion, thereby improving reactivity with the gas. Gases such as hydrogen, carbon monoxide, and carbon dioxide have relatively low viscosity at reaction temperatures and are easy to diffuse, and the reaction with electrodes is rate-limited by the catalytic reaction. For an electrode in contact with a gas containing a large amount of such components, for example, reducing the average pore diameter to increase the chance of contact with the catalyst reduces the polarization resistance of the catalytic reaction and improves reactivity. The properties of the gases that the first electrode 5 and the second electrode 7 respectively contact are often different from each other. By adjusting the average pore diameter of the first pores 53 and the average pore diameter of the second pores 73 in accordance with the properties of each gas, particularly viscosity, and making the average pore diameter of the second pores 73 different from the average pore diameter of the first pores 53, the reactivity of the first electrode 5 and the second electrode 7 with the respective gases in contact therewith is improved. Therefore, according to the cell 1 of the present embodiment, performance is improved.

[0032] The average cross-sectional area of the first pores 53 is, for example, 2 μm ２ or more and 10 μm ２ or less, particularly 2 μm ２ or more and 6 μm ２ or less, and further 2 μm ２ or more and 5 μm ２ or less. The average perimeter of the first pores 53 may be, for example, 5 μm or more and 20 μm or less, particularly 5 μm or more and 15 μm or less.

[0033] In a cross section perpendicular to the second surface 62, the second pores 73 may have an average cross-sectional area larger than that of the first pores 53. The average cross-sectional area of the second pores 73 is, for example, 6 μm ２ or more and 40 μm ２ or less, particularly 10 μm ２ or more and 40 μm ２ or less, and further 15 μm ２ or more and 40 μm ２ or less. The area ratio of the second pores 73 in the cross section of the second electrode 7 may be larger than the area ratio of the first pores 53 in the cross section of the first electrode 5. The area ratio of pores refers to the ratio of the total area of pores located in the measured cross section to the total area of the measured cross section.

[0034] In a cross section perpendicular to the second surface 62, the second pores 73 may have an average perimeter larger than that of the first pores 53. The average perimeter of the second pores 73 may be, for example, 20 μm or more and 100 μm or less, particularly 25 μm or more and 100 μm or less.

[0035] In a cross section perpendicular to the second surface 62, the second pores 73 may have higher pore connectivity than the first pores 53. This makes it easier for the average pore diameter of the second pores 73 to be larger than the average pore diameter of the first pores 53. Therefore, according to the cell 1 according to the present embodiment, performance is improved.

[0036] Here, the connectivity of the pores can be evaluated using an index A relating to the distribution of pore diameters, the Ferret diameter, etc. Details of index A will be described later. Specifically, the index A of the first electrode 5 having the first pores 53 may be, for example, 0.7 or more and 3.5 or less. Also, the index A of the second electrode 7 having the second pores 73 may be, for example, 7.5 or more and 16.0 or less. The Ferret diameter of the pores is the length of the sides of the rectangle circumscribing the pores. The Ferret diameter of the second pores 73 may be larger than the Ferret diameter of the first pores 53. For example, as the rectangle circumscribing the pores, a rectangle having sides along the thickness direction T and sides along the length direction L and / or width direction W may be selected. For example, the average length of the sides along the thickness direction T of the second pores 73, i.e., the average Ferret diameter in the thickness direction T, may be larger than that of the first pores 53.

[0037] Furthermore, the second pores 73 may include those in which the length in the direction perpendicular to the first surface 61, i.e., the thickness direction T, is greater than the length in the direction parallel to the first surface 61, i.e., the length direction L and / or the width direction W. For example, the second pores 73 may include those in which the ferret diameter in the thickness direction T is greater than the ferret diameter in the length direction L and / or the width direction W. The second pores 73 may include more pores in which the ferret diameter in the thickness direction T is greater than the ferret diameter in the length direction L and / or the width direction W than than those in which it is not.

[0038] Furthermore, the average particle size of the second material 72 may be larger than the average particle size of the first material 52. This makes it easier for the average pore diameter of the second pore 73 to be larger than the average pore diameter of the first pore 53. For this reason, the performance of the cell 1 according to this embodiment is improved.

[0039] Furthermore, the particle size ratio of the second material 72 and the second catalyst 71 ((particle size of the second material 72) / (particle size of the second catalyst 71)) may be greater than the particle size ratio of the first material 52 and the first catalyst 51 ((particle size of the first material 52) / (particle size of the first catalyst 51)). This makes it easier to reduce the amount of unreduced first catalyst 51 present in the first electrode 5. For this reason, the performance of the cell 1 according to this embodiment is improved.

[0040] The second electrode 7 may have second electrodes 7a and 7b located at both ends in the thickness direction T of the cell 1. The second electrode 7a has first ends 7a1 and 7a2 located at both ends in the width direction W. The second electrode 7b has second ends 7b1 and 7b2 located at both ends in the width direction W.

[0041] The outer surface of the solid electrolyte layer 6 facing the second electrode 7 may have a boundary portion 60 where the second electrode 7 is not located. The boundary portion 60 extends along the length direction L and separates the second electrode 7a and the second electrode 7b.

[0042] In other words, the second electrodes 7a and 7b may have a first end and a second end separated from the first end by a boundary portion extending along the first direction (length direction L). This allows for stress relief in the second electrode 7, making it less likely for cracks to occur in the second electrode 7.

[0043] Cell 1 may have two or more boundary portions 60. As shown in Figure 1A, the boundary portion 60 may have two boundary portions 60a and 60b. Boundary portion 60a is located between the first end 7a1 and the second end 7b1. Boundary portion 60b is located between the first end 7a2 and the second end 7b2.

[0044] Furthermore, the second electrode 7 may have two or more portions separated by two or more boundary portions 60. As shown in Figure 1A, the second electrode 7 may have second electrodes 7a and 7b.

[0045] The first electrode 5 and the solid electrolyte layer 6 may have end faces e1 to e4. End face e1 is located at one end in the width direction W of the electrode 5a and the solid electrolyte layer 6a. End face e2 is located at the other end in the width direction W of the electrode 5a and the solid electrolyte layer 6a.

[0046] End face e3 is positioned opposite end face e1, with the separation portion 8a in between. End face e4 is positioned opposite end face e2, with the separation portion 8b in between.

[0047] In other words, the first electrode 5 and the solid electrolyte layer 6 may have an end face e1 and an end face e3 separated from end face e1. Furthermore, the first electrode 5 and the solid electrolyte layer 6 may have an end face e2 and an end face e4 separated from end face e2. In other words, the first electrode 5 and the solid electrolyte layer 6 may have a third end and a fourth end separated from this third end.

[0048] The distance between end face e1 and end face e3, i.e., the width of the separation portion 8a, may be, for example, 0.5 mm to 4.0 mm. The distance between end face e2 and end face e4, i.e., the width of the separation portion 8b, may be, for example, 0.5 mm to 4.0 mm. The widths of the separation portion 8a and the separation portion 8b may be the same or different.

[0049] The second electrode 7a may be positioned in a location corresponding to the first surface f1. The second electrode 7b may be positioned in a location corresponding to the second surface f2. In other words, the second electrodes 7a and 7b may be positioned facing the first surface f1 and / or the second surface f2. This makes it even less likely for cracks to occur in the second electrode 7 compared to the case where the second electrode 7 is positioned facing the sides f3 and f4, thereby improving the reliability of cell 1.

[0050] Cell 1 may further include a porous support 2 located on the opposite side of the solid electrolyte layer 6, with the first electrode 5 in between. The support 2 may have a first surface f1 and a second surface f2 opposite to the first surface f1. The support 2 may also have a pair of side surfaces f3 and f4 connecting the first surface f1 and the second surface f2. The external shape of the support 2 may be, for example, columnar. Hereinafter, the first surface f1, the second surface f2 and the side surfaces f3 and f4 may be referred to as the circumferential surface 20 of the support 2. The element portion 3 may be positioned to cover the circumferential surface 20.

[0051] The first surface f1 and the second surface f2 may be flat. The pair of side surfaces f3 and f4 may be curved surfaces that project in the width direction W from both ends of the substantially flat first surface f1 and the second surface f2.

[0052] The support 2 may have internal flow channels 2a extending in the longitudinal direction L, which is the first direction. Fluid flows through the flow channels 2a. An example of the support 2 shown in Figure 1A has six flow channels 2a. The support 2 is gas permeable and allows the first gas flowing through the flow channels 2a to pass through to the first electrode 5. The support 2 may be conductive.

[0053] The material of the support 2 includes, for example, an iron group metal component and an inorganic oxide. The iron group metal component may be, for example, metallic Ni (nickel) and / or NiO. The inorganic oxide may be, for example, a specific rare earth element oxide. The rare earth element oxide may include, for example, one or more rare earth elements selected from Sc, Y, La, Nd, Sm, Gd, Dy, and Yb.

[0054] Cell 1 may have a separation portion 8 on the circumferential surface 20 of the support 2 in which the first electrode 5 and the solid electrolyte layer 6 are not located. In other words, the first electrode 5 and the solid electrolyte layer 6 may be separated along the circumferential direction of the support 2. This allows for stress relief in the first electrode 5 and the solid electrolyte layer 6, making it less likely for cracks to occur in the first electrode 5 and the solid electrolyte layer 6. At least one separation portion 8 is sufficient.

[0055] Cell 1 may have, for example, two or more separation portions 8. The separation portions 8 may have separation portions 8a and 8b on the first surface f1 of the support 2. The first electrode 5 may have an electrode 5a located between the separation portions 8a and 8b. The solid electrolyte layer 6 may have a solid electrolyte layer 6a located between the separation portions 8a and 8b. One of the separation portions 8a and 8b may be located on the second surface f2.

[0056] A sealing portion 9 connecting the first electrode 5 and the solid electrolyte layer 6 may be located in the separation portion 8. The sealing portion 9 extends along the first direction (length direction L). The sealing portion 9 may be located between end face e1 and end face e3. Alternatively, the sealing portion 9 may be located between end face e2 and end face e4. In other words, cell 1 may have a sealing portion 9 between the third end and the fourth end. The sealing portion 9 may be in airtight contact with the third end and the fourth end.

[0057] The sealing portion 9 may extend to both ends in the longitudinal direction L where the separation portion 8 is located, as shown in Figure 1B. The second electrode 7a may be positioned in contact with the sealing portion 9. This can further improve the adhesive strength between the second electrode 7 and the support 2. The sealing portion 9 may be positioned so as to protrude from the surface of the solid electrolyte layer 6 toward the second electrode 7a, or it may be flush with the surface of the solid electrolyte layer 6.

[0058] The second electrode 7a may be in contact with the sealing portion 9 located in both the separation portions 8a and 8b, as shown in Figures 1A and 1B. The second electrode 7a may be in contact with only one of the separation portions 8a and 8b. Alternatively, the second electrode 7a may be positioned away from the separation portions 8a and 8b so as not to contact the sealing portion 9.

[0059] The sealing portion 9 may include, for example, a first material 52 and / or a second material 72. The sealing portion 9 may also include, for example, yttria-stabilized zirconia (YSZ). Furthermore, the sealing portion 9 may include oxides other than the first material 52 and / or the second material 72.

[0060] Here, the arrangement, composition, and average particle size of the first catalyst 51 and first material 52 in the first electrode 5, and the second catalyst 71 and second material 72 in the second electrode 7 are obtained as follows. For example, the polished cross-section of the cell 1 containing the first electrode 5 and the second electrode 7 can be measured by image analysis using an SEM (scanning electron microscope). Specifically, the cross-section is subjected to elemental analysis using an EDX (energy-dispersive X-ray analyzer) or EPMA (electron probe microanalyzer) to identify the first catalyst 51, the first material 52, the second catalyst 71, the second material 72, and pores, and to determine the arrangement of the first electrode 5 and the second electrode 7. Cross-sectional images of the first electrode 5 and the second electrode 7 are taken, for example, at a magnification of 1000x. The cross-sectional images of the first catalyst 51, first material 52, second catalyst 71, and second material 72, which were identified by elemental analysis, can be analyzed using image analysis software such as ImageJ, and the average particle size, particle size ratio, etc., can be calculated based on the cross-sectional area, equivalent circle diameter, etc.

[0061] Furthermore, the arrangement, shape, average pore diameter, average cross-sectional area, and average circumference of the first pores 53 in the first electrode 5 and the second pores 73 in the second electrode 7 are obtained as follows. For the first pores 53, a region of the cross-sectional image that does not include the first surface 61 of the solid electrolyte layer 6 and the surface of the first electrode 5 is selected as the analysis region of the first electrode 5. The surface of the first electrode 5 is the surface of the first electrode 5 opposite to the solid electrolyte layer 6. For example, when the thickness of the first electrode 5 is t1, a region that is 0.1 × t1 or more away from the first surface 61 and the surface of the first electrode 5 is selected as the analysis region. The image of the selected analysis region is binarized to identify the first pores 53. The first pores 53 are voids located between or inside the first catalyst 51 and the first material 52, and have various shapes in cross-section. By performing image analysis on the identified first pores 53, the cross-sectional area, equivalent circle diameter, circumference, Ferret diameter, and their average values ​​for each first pore 53 can be calculated. Similarly, for the second pores 73, the analysis region of the second electrode 7 can be defined as that of the first electrode 5, and image analysis can be performed to calculate the cross-sectional area, equivalent circle diameter, circumference, Ferret diameter, and their average values ​​for each second pore 73.

[0062] Furthermore, index A, which relates to the distribution of pore diameters of the first pore 53 and the second pore 73, is calculated by using the cross-sectional area of ​​each pore calculated by image analysis, and dividing the sum of the squares of the cross-sectional areas of each pore by the square of the sum of the cross-sectional areas of each pore. That is, the cross-sectional area of ​​each pore is divided by S ｋ When this is the case, A = Σ ｋ－１ ｎ (S ｋ ^2) / (Σ ｋ－１ ｎ S ｋ Let the value be )^2 × 100. The larger the index A, the greater the proportion of pores with a large cross-sectional area. The Ferret diameters of the first pores 53 and the second pores 73 can be calculated, for example, by image analysis of the first Ferret diameter along the first surface 61 and the second Ferret diameter along the thickness direction. The second pore 73 may have a second Ferret diameter along the thickness direction that is larger than the first Ferret diameter along the first surface 61. The second pores 73 may contain more pores with a second Ferret diameter larger than the first Ferret diameter than those with a second Ferret diameter that is not larger.

[0063] To make the average pore diameter of the first pores 53 in the first electrode 5 different from the average pore diameter of the second pores 73 in the second electrode 7, for example, the average particle sizes of the first material 52 and the second material 72 can be made different. Alternatively, the particle sizes of the pore-forming material mixed into the materials of the first electrode 5 and the second electrode 7 can be made different. For example, by making the average particle size of the second material 72 and pore-forming material contained in the material of the second electrode 7 larger than the average particle size of the first material 52 and pore-forming material contained in the material of the first electrode 5, a cell 1 can be obtained in which the average pore diameter of the second pores 73 is larger than the average pore diameter of the first pores 53. However, there are no restrictions on the manufacturing method of a cell 1 in which the average pore diameter of the first pores 53 and the average pore diameter of the second pores 73 are different, and it may be manufactured by any method.

[0064] [Second Embodiment] <Cell Configuration> Figure 2A is a cross-sectional view showing an example of a cell according to the second embodiment. Figure 2B is a side view showing an example of a cell according to the second embodiment.

[0065] Figures 2A and 2B illustrate a three-dimensional Cartesian coordinate system including the Z-axis, where the vertically upward direction is positive and the vertically downward direction is negative. In Figures 2A and 2B, components similar to those in cell 1 shown in Figures 1A and 1B are denoted by the same reference numerals, and their explanations are omitted or simplified.

[0066] The cell 1 according to this embodiment is columnar or cylindrical. As shown in Figure 2B, the overall shape of the cell 1 when viewed from the side may be, for example, rectangular. The length of the cell 1 in the longitudinal direction, i.e., in the Z-axis direction, may be 5 cm to 50 cm. The length of the cell 1 in the X-axis direction and / or Y-axis direction perpendicular to the Z-axis direction may be, for example, 1 mm to 10 cm.

[0067] As shown in Figures 2A and 2B, the cell 1 has an element section 3 comprising a solid electrolyte layer 6, a first electrode 5 as a first porous layer, and a second electrode 7 as a second porous layer.

[0068] The solid electrolyte layer 6 has a first surface 61 and a second surface 62 located on the opposite side of the first surface 61.

[0069] The first electrode 5 is located on the first surface 61. The first electrode 5 includes a first catalyst 51, a first material 52 having ion conductivity, and a first pore 53.

[0070] The second electrode 7 is located on the second surface 62. The second electrode 7 includes a second catalyst 71, an ion-conducting second material 72, and a second pore 73. The second catalyst 71 may contain elements contained in the first catalyst 51. The second material 72 may contain oxides contained in the first material 52.

[0071] In this embodiment, the properties of the first pores 53 located at the first electrode 5 differ from those of the second pores 73 located at the second electrode 7. This reduces the polarization resistance at the first electrode 5 and the second electrode 7, improving reactivity. Therefore, the performance of the cell 1 according to this embodiment is improved.

[0072] Furthermore, the porosity of the first electrode 5 in cell 1 may be smaller than that of the second electrode 7. This reduces the polarization resistance in the first electrode 5 and the second electrode 7, improving reactivity. Therefore, the performance of cell 1 according to this embodiment is improved.

[0073] Furthermore, the average pore diameter of the second pores 73 in cell 1 may be larger than the average pore diameter of the first pores 53. This reduces the polarization resistance in the first electrode 5 and the second electrode 7, improving reactivity. Therefore, the performance of cell 1 according to this embodiment is improved.

[0074] Cell 1 may further include a porous support 2. The support 2 may be located on the opposite side of the solid electrolyte layer 6, with the first electrode 5 in between.

[0075] The support 2 may have a cylindrical shape. The shape of the support 2 may be, for example, cylindrical. The shape of the support 2 may be, for example, elliptical or rectangular.

[0076] The support 2 may have an inner surface 21 and an outer surface 22. The first electrode 5 may face the outer surface 22. The support 2 may have a flow channel 2a inside the inner surface 21 that extends in the Z-axis direction as the first direction. A fluid flows through the flow channel 2a. The support 2 is gas permeable and allows the first gas flowing through the flow channel 2a to pass through to the first electrode 5. The support 2 may be conductive.

[0077] <Configuration of Cell Stack Device> Figure 3 is a perspective view showing an example of a cell stack device according to the embodiment.

[0078] As shown in Figure 3, the cell stack device 10 using the cell 1 according to each embodiment described above comprises a cell stack 15 having a plurality of cells 1, a first manifold 11, a second manifold 12, an inflow channel 13, and an outflow channel 14.

[0079] The cell stack 15 has one end of each of the multiple cells 1 fixed to the first manifold 11 in a first direction, that is, in the longitudinal direction L shown in Figure 1B or the Z-axis direction shown in Figure 2B, and the other end in the first direction fixed to the second manifold 12.

[0080] The first manifold 11 is connected to the inflow channel 13. A first gas flows into the inflow channel 13. The first gas may contain, for example, carbon monoxide (CO). The carbon monoxide (CO) flowing in from the inflow channel 13 may be supplied from one end of the cell 1 to the channel 2a (see Figures 1A and 2A) via the first manifold 11.

[0081] The second manifold 12 is connected to the outflow channel 14. Carbon dioxide (CO2) is emitted from the other end of cell 1. ２ The wastewater flows out into the outflow channel 14 via the second manifold 12.

[0082] As described above, when supplying the first gas containing carbon monoxide (CO) to the first manifold 11, water vapor (H) is present on the outer circumference of the cell stack device 10. ２ A second gas containing O) should be supplied. Note that in the process of the first gas containing carbon monoxide (CO) flowing through channel 2a, carbon dioxide (CO) ２ ) is generated.

[0083] In such a cell stack device 10, as described above, by having a cell stack 15 that includes a cell 1 with improved performance, the cell stack device 10 can be made to have improved performance.

[0084] Although the present disclosure has been described in detail above, the present disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of the present disclosure. For example, the first electrode 5 and the second electrode 7 of cell 1 may be swapped, and the first gas and the second gas supplied to cell 1 may be swapped.

[0085] In one embodiment, (1) the cell comprises a solid electrolyte layer having a first surface and a second surface located opposite to the first surface; a first porous layer located on the first surface and containing a first catalyst, an ion-conductive first material, and first pores; and a second porous layer located on the second surface and containing a second catalyst, an ion-conductive second material, and second pores, wherein the properties of the first pores are different from those of the second pores.

[0086] Furthermore, (2) in the cell described in (1) above, the first porous layer is in contact with the first gas, the second porous layer is in contact with the second gas which has a higher water vapor content than the first gas, and the porosity of the first porous layer may be smaller than the porosity of the second porous layer.

[0087] Furthermore, (3) in the cell described in (1) or (2) above, the first porous layer is in contact with the first gas, the second porous layer is in contact with the second gas which has a higher water vapor content than the first gas, and the average pore diameter of the second porous layer may be greater than the average pore diameter of the first porous layer.

[0088] Furthermore, (4) In any one of the cells described in (1) to (3) above, the second material may contain an oxide included in the first material.

[0089] Furthermore, (5) In any one of the cells described in (1) to (4) above, the second catalyst may contain elements included in the first catalyst.

[0090] Furthermore, (6) any one of the cells described in (1) to (5) above may further include a porous support located on the opposite side of the solid electrolyte layer from the first porous layer.

[0091] Furthermore, (7) In the cell of (6) above, the support has a cylindrical shape with an inner surface and an outer surface, and the first porous layer may face the outer surface.

[0092] In one embodiment, (8) the cell stacking device has a cell stack including any one of the cells described in (1) to (7) above.

[0093] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0094] 1 Cell 2 Support 2a Flow channel 3 Element section 5 First electrode 6 Solid electrolyte layer 7 Second electrode 10 Cell stack device 51 First catalyst 52 First material 53 First pore 61 First surface 62 Second surface 71 Second catalyst 72 Second material 73 Second pore

Claims

1. A cell comprising: a solid electrolyte layer having a first surface and a second surface located opposite to the first surface; a first porous layer located on the first surface and containing a first catalyst, an ion-conductive first material, and first pores; and a second porous layer located on the second surface and containing a second catalyst, an ion-conductive second material, and second pores, wherein the properties of the first pores differ from those of the second pores.

2. The cell according to claim 1, wherein the first porous layer is in contact with a first gas, the second porous layer is in contact with a second gas having a higher water vapor content than the first gas, and the porosity of the first porous layer is smaller than the porosity of the second porous layer.

3. The cell according to claim 1, wherein the first porous layer is in contact with a first gas, the second porous layer is in contact with a second gas having a higher water vapor content than the first gas, and the average pore diameter of the second pores is greater than the average pore diameter of the first pores.

4. The cell according to claim 1, wherein the second material comprises an oxide contained in the first material.

5. The cell according to claim 1, wherein the second catalyst comprises the elements contained in the first catalyst.

6. The cell according to claim 1, further comprising a porous support located on the opposite side of the solid electrolyte layer, with the first porous layer in between.

7. The cell according to claim 6, wherein the support has a cylindrical shape with an inner surface and an outer surface, and the first porous layer faces the outer surface.

8. A cell stacking apparatus having a cell stack containing the cell described in any one of claims 1 to 7.

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