Method for manufacturing solid oxide cells

Abstract

This invention provides a method for manufacturing a high-strength solid oxide cell. [Solution] A method for manufacturing a solid oxide cell comprises: an electrode layer formation step of forming an electrode layer 2 on a support layer 1 containing NiO and ZrO2 containing 3 mol% Y2O3; an electrolyte layer formation step of forming an electrolyte layer 3 on the electrode layer 2; and a firing step of firing at least the support layer 1 at 1280°C to 1300°C.

Description

[Technical Field]

[0001] This invention relates to a method for producing solid oxide type cells. [Background technology]

[0002] Conventionally, systems equipped with solid oxide cells (SOCs), such as solid oxide fuel cells (SOFCs) and solid oxide steam electrolysis (SOEC) devices, have been known. Such systems are attracting attention as highly efficient energy conversion devices.

[0003] Patent Document 1 discloses a solid oxide cell (a single cell in Patent Document 1) comprising a fuel electrode, an electrolyte layer, and an air electrode. The solid oxide cell according to Patent Document 1 is a fuel electrode-supported cell in which the fuel electrode supports the electrolyte layer, air electrode, etc., and the strength of the entire solid oxide cell is ensured by the fuel electrode. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-58262 [Overview of the project] [Problems that the invention aims to solve]

[0005] Solid oxide fuel cells often experience temperature variations within them during power generation and startup, with temperature differences between high-temperature and low-temperature areas sometimes exceeding 100°C. This can lead to thermal stress due to differences in the thermal expansion coefficients of the solid oxide cell's constituent materials, potentially causing cracking. In particular, for commercial fuel cell systems composed of numerous solid oxide cells, improving the strength of the solid oxide cells is crucial due to the need for series-system reliability. Even in household-scale solid oxide cells, stricter design and operation are necessary to suppress cracking, leading to increased costs and reduced operability. Furthermore, the solid oxide cell described in Patent Document 1 improves the strength of the fuel electrode while maintaining its power generation performance, thus limiting the materials and strengths that can be selected for the fuel electrode.

[0006] This invention has been made in view of the above-mentioned problems, and its purpose is to provide a method for manufacturing a solid oxide cell with high strength. [Means for solving the problem]

[0007] The characteristic configuration of the method for producing a solid oxide cell according to the present invention is an electrode layer formation step in which an electrode layer is formed on a support layer containing NiO and ZrO2 containing 3 mol% Y2O3, The electrolyte layer formation step involves forming an electrolyte layer on the electrode layer, The present invention includes a firing step of firing the support layer at a temperature of 1280°C to 1300°C.

[0008] According to this configuration, by manufacturing a solid oxide cell in which an electrode layer is formed on a support layer made of ZrO2 containing NiO and 3 mol% Y2O3, the electrode layer can be supported by a high-strength support layer, thereby improving the strength of the solid oxide cell. On the other hand, ZrO2 containing 3 mol% Y2O3 (3YSZ) is prone to phase transition from tetragonal to monoclinic under high water vapor partial pressure of 100-400°C, and it is known that hydrothermal degradation due to such a phase transition occurs, leading to a decrease in strength and structural collapse. However, in this configuration, by performing a firing step in which the support layer is fired at 1280°C to 1300°C, it is possible to suppress the occurrence of hydrothermal degradation. As a result, we have been able to provide a method for manufacturing a solid oxide cell that can increase the strength of the electrode layer while reducing the risk of hydrothermal degradation.

[0009] Another characteristic feature is that it further includes a counter electrode layer formation step, in which a counter electrode layer is formed on the electrolyte layer.

[0010] This configuration makes it possible to fabricate a three-layer solid oxide cell having a high-strength electrode layer.

[0011] Another characteristic feature is that the firing step is performed between the electrolyte layer formation step and the counter electrode layer formation step.

[0012] According to this configuration, by performing a firing step after the electrolyte layer formation step, the support layer and the electrolyte layer can be co-sintered to produce a solid oxide type cell, thereby simplifying the manufacturing process.

[0013] Another characteristic feature is that, after the firing step, there is a further reduction step in which at least the support layer is reduced.

[0014] According to this configuration, the reduction step reduces NiO in the support layer to form ZrO2 containing Ni and 3 mol% Y2O3.

[0015] As another characteristic configuration, the thickness of the electrolyte layer is 50 μm or less.

[0016] According to this configuration, by thinning the electrolyte layer, it is possible to improve the strength of the solid oxide fuel cell while miniaturizing the solid oxide fuel cell. In addition, the amount of expensive electrolyte material used can be reduced.

Brief Description of the Drawings

[0017] [Figure 1] It is a schematic diagram of a solid oxide fuel cell according to the present invention. [Figure 2] It is a diagram showing the relationship between porosity and fracture stress. [Figure 3] It is a diagram showing the fracture stress before the hydrothermal degradation treatment. [Figure 4] It is a diagram showing the fracture stress after the hydrothermal degradation treatment.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of a method for manufacturing a solid oxide fuel cell according to the present invention will be described based on the drawings. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist thereof.

[0019] 〔Solid Oxide Fuel Cell〕 As shown in FIG. 1, a solid oxide fuel cell E according to the first embodiment includes a support layer 1, an electrode layer 2, an electrolyte layer 3, and a counter electrode layer 4. The electrode layer 2 is formed on the support layer 1, the electrolyte layer 3 is formed on the electrode layer 2, and the counter electrode layer 4 is formed on the electrode layer 2. That is, the support layer 1, the electrode layer 2, the electrolyte layer 3, and the counter electrode layer 4 are laminated in this order. The solid oxide fuel cell E can be used for a solid oxide fuel cell (SOFC) or a solid oxide steam electrolysis cell (SOEC).

[0020] The support layer 1 supports the electrode layer 2, the electrolyte layer 3, and the counter electrode layer 4, thereby maintaining the strength of the solid oxide cell E. In other words, the support layer 1 plays the role of a support for the components of the solid oxide cell E. Furthermore, in this embodiment, the laminate consisting of the support layer 1 and the electrode layer 2 acts as the fuel electrode.

[0021] Support layer 1 consists of ZrO2 (Ni-3YSZ), which is a cermet made of a metal-ceramic composite material, containing Ni and 3 mol% Y2O3. Here, ZrO2 containing Y2O3 is yttria-stabilized zirconia (YSZ), and among YSZ, 3YSZ containing 3 mol% Y2O3 is known to have high mechanical strength, while 8YSZ containing 8 mol% Y2O3 is known to have high ionic conductivity. Therefore, by using a high-strength 3YSZ-based material as support layer 1, the strength of the solid oxide type cell E can be improved. In addition, the Ni contained in support layer 1 is reduced nickel oxide (NiO).

[0022] 3YSZ is known to undergo a phase transition from tetragonal to monoclinic under high water vapor partial pressures of 100-400°C. This phase transition causes a 4.5% volume expansion in 3YSZ, leading to crack propagation and reduced strength, structural collapse, and ultimately, a decline in mechanical properties. Due to the risk of such hydrothermal degradation, when using 3YSZ or Ni-3YSZ, operational constraints are necessary, such as replacing the atmosphere with a dry one to prevent high water vapor partial pressures during startup, shutdown, and storage of solid oxide cells operating at 100-400°C. This has resulted in increased costs and reduced operability.

[0023] However, the Ni-3YSZ in the support layer 1 of this embodiment is less prone to phase transitions before and after hydrothermal degradation treatment. Therefore, even if the solid oxide cell E is used under high water vapor partial pressure of 100 to 400°C, hydrothermal degradation can be avoided or reduced. Here, hydrothermal degradation treatment refers to immersing the support layer 1 in hot water at 140°C for 48 hours. This condition causes the phase transition of YSZ to reach its saturation value.

[0024] Furthermore, the Ni-3YSZ used in the support layer 1 exhibits a change in fracture stress of 15% or less before and after hydrothermal degradation treatment. Therefore, by using Ni-3YSZ, which has higher strength, as the constituent material of the support layer 1 instead of Ni-8YSZ, the strength of the solid oxide type cell E can be increased while suppressing hydrothermal degradation. Here, the fracture stress is determined by converting the load at the time of failure of the support layer 1 into the fracture stress in a ring-on-ring test (ASTM standard C1499). Such a support layer 1 is obtained by undergoing a firing step in which the support layer 1 is fired at a temperature of 1280°C to 1300°C, as described later.

[0025] An electrode layer 2 is formed on top of the support layer 1. The electrode layer 2 functions as a fuel electrode in an electrochemical reaction. The thickness of the electrode layer 2 is preferably less than the thickness of the support layer 1, for example, about 1 μm to 100 μm, preferably 5 μm to 50 μm. Such a thickness makes it possible to reduce the amount of expensive electrode layer material used, thereby lowering costs while ensuring sufficient electrode performance.

[0026] The electrode layer 2 is preferably made of a metal-ceramic two-phase mixture, and Ni-YSZ can be used as the electrode layer 2. In this embodiment, the electrode layer 2 is preferably ZrO2(Ni-8YSZ) containing Ni and 8 mol% Y2O3. Since Ni-8YSZ has superior ionic conductivity compared to Ni-3YSZ used in the support layer 1, a solid oxide type cell E with high mechanical strength and conductivity can be obtained by supporting the highly conductive electrode layer 2 with a highly strong support layer 1.

[0027] The electrode layer 2 has multiple pores on its interior and surface to allow gas permeability. In other words, the electrode layer 2 is formed as a porous layer. The porosity of the electrode layer 2 is preferably 20% to 60% from the viewpoint of forming a three-dimensional gas diffusion path. The size of the pores can be appropriately selected to be suitable for smooth reaction during electrochemical reactions.

[0028] The electrolyte layer 3 is formed on the electrode layer 2, and the thickness of the electrolyte layer 3 is preferably less than the thickness of the support layer 1, for example, 5 μm to 50 μm. By bonding the electrolyte layer 3 to the support layer 1, the solid oxide cell E as a whole can be made highly robust.

[0029] Suitable materials for the electrolyte layer 3 include YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), which are electrolyte materials that conduct oxygen ions, and zirconia-based ceramics.

[0030] The electrolyte layer 3 is densely constructed to shield against gas leaks of the anode gas and cathode gas, and to exhibit high ionic conductivity. The density of the electrolyte layer 3 is preferably 95% or higher, and more preferably 98% or higher. If the electrolyte layer 3 is a uniform layer, its density is preferably 95% or higher, and more preferably 98% or higher.

[0031] The counter electrode layer 4 can be formed as a thin layer on top of the electrolyte layer 3. When the counter electrode layer 4 is a thin layer, its thickness can be, for example, about 20 μm to 100 μm. By using such a thickness, it is possible to reduce the amount of expensive counter electrode layer material used, thereby lowering costs while ensuring sufficient electrode performance.

[0032] As the material for the counter electrode layer 4, for example, composite oxides such as LSCF (lanthanum-strontium-cobalt-ferrite) and LSM (lanthanum-strontium-manganese), ceria oxides, and mixtures thereof can be used. In particular, it is preferable that the counter electrode layer 4 contains a perovskite-type oxide containing two or more elements selected from the group consisting of La, Sr, Sm, Mn, Co, and Fe. The counter electrode layer 4 constructed using the above materials functions as a cathode. In this embodiment, the counter electrode layer 4 is, for example, La 0.6 Sr 0.4 Co 0.2 Fe 0.8 It is O3.

[0033] A reaction-preventing layer may be provided between the electrolyte layer 3 and the counter electrode layer 4, which can prevent the reaction between the components of the electrolyte layer 3 and the components of the counter electrode layer 4. The reaction-preventing layer effectively suppresses the reaction between the constituent materials of the electrolyte layer 3 and the constituent materials of the counter electrode layer 4, thereby improving the long-term stability of the performance of the solid oxide cell E. The reaction-preventing layer may be, for example, Gd 0.1 Ce 0.9 Ceria-based materials such as GDC (gadolinium-doped ceria) containing O2 can be used.

[0034] [Method for manufacturing solid oxide cells] Next, a method for manufacturing solid oxide cell E will be described. The method for manufacturing solid oxide cell E includes an electrode layer formation step of forming an electrode layer 2 on a support layer 1, an electrolyte layer formation step of forming an electrolyte layer 3 on the electrode layer 2, a counter electrode layer formation step of forming a counter electrode layer 4 on the electrolyte layer 3, a firing step of firing at least the support layer 1, and a reduction step of reducing at least the support layer 1.

[0035] In the electrode layer formation step, first, a mixture obtained by mixing nickel oxide (NiO) powder and ZrO2 (3YSZ) powder containing 3 mol% Y2O3 is molded and pressed, and calcined at a firing temperature of 1100°C to obtain the support layer 1. The support layer 1 may also be obtained by tape casting. The 3YSZ powder is preferably produced by hydrolysis. Using hydrolysis makes it easier to achieve a uniform distribution of yttrium in the mixture. The mixing ratio of NiO and 3YSZ can be any, but it is preferable that the volume ratio of Ni in the Ni-3YSZ related to the support layer 1 after the reduction step described later be 30% to 50%, preferably 30% to 40%. If the volume ratio of Ni in the support layer 1 after the reduction step is 30% or more, a decrease in electronic conductivity can be suppressed, and if the volume ratio of Ni is 50% or less, preferably 40% or less, a decrease in the strength of the support layer 1 can be suppressed. Furthermore, in forming the support layer 1, an acrylic porosity-forming material can be added to the NiO and 3YSZ mixture to obtain a support layer 1 with any desired porosity. Porosity refers to the volume percentage (volume %) of pores in the Ni-3YSZ related to the support layer 1. The porosity is designed according to the thickness of the support layer 1 and the design current density of the solid oxide cell E. Since there is a correlation between the fracture stress of the support layer 1 and the porosity, increasing the porosity decreases the fracture stress, and decreasing the porosity increases the fracture stress.

[0036] Next, an electrode layer 2 is formed on the support layer 1. The electrode layer 2 can be formed using a screen printing method, in which a slurry containing the electrode layer material is prepared and the slurry is screen printed onto the surface of the support layer 1, or a tape casting method.

[0037] In the electrolyte layer formation step, an electrolyte layer 3 is formed on top of the electrode layer 2 formed in the electrode layer formation step. Similar to the electrode layer formation step, screen printing or tape casting methods can be used in the electrolyte layer formation step. Alternatively, the electrode layer 2 and the electrolyte layer 3 may be attached with tape simultaneously.

[0038] After forming the electrode layer 2 in the electrolyte layer formation step, a firing step is performed to co-sinter the support layer 1, electrode layer 2, and electrolyte layer 3. The firing step is preferably carried out at a firing temperature of 1280°C to 1300°C for 5 to 10 hours. If the firing temperature is between 1280°C and 1300°C, hydrothermal degradation of Ni-3YSZ can be suppressed.

[0039] Next, a reduction step is performed to reduce NiO and other elements in the support layer 1, thereby generating Ni-containing particles. The reduction conditions are not particularly limited, but it is preferable to use conditions that are optimal for generating Ni-3YSZ, for example, by reducing only NiO and not 3YSZ. The reduction is preferably carried out in a nitrogen atmosphere or a hydrogen atmosphere at a temperature range of 750°C to 850°C.

[0040] Finally, a counter electrode layer formation step is performed to form a counter electrode layer 4 on the electrolyte layer 3. In the counter electrode layer formation step, as in the electrode layer formation step, a screen printing method or tape casting method can be used. After forming the counter electrode layer 4, the support layer 1, electrode layer 2, electrolyte layer 3 and counter electrode layer 4 are co-sintered at a temperature lower than the firing temperature in the firing step, for example, 1200°C, to obtain a solid oxide type cell E. Alternatively, a reaction prevention layer may be formed between the electrolyte layer 3 and the counter electrode layer 4 by a screen printing method or the like, and then the counter electrode layer 4 may be formed on top of the reaction prevention layer.

[0041] [Examples] Examples of the present invention are described below. The present invention is not limited to these examples.

[0042] [Example 1] In the method for manufacturing the solid oxide cell E described above, the support layer 1 was formed by performing the electrode layer formation step. In Example 1, powder of ZrO2 (3YSZ, TZ-3Y-E manufactured by Tosoh Corporation) containing 3 mol of Y2O3 and powder of NiO (NiO-IP B1 manufactured by Sumitomo Metal Mining Co., Ltd.) were used, respectively.

[0043] After weighing NiO and 3YSZ separately, they were immersed in a 4% aqueous solution of polyvinyl alcohol and mixed for 30 minutes using a kneader to obtain a slurry. NiO and 3YSZ were mixed in a weight ratio of 55:45. The obtained slurry was dried at 60°C for more than 40 hours, then pulverized and sieved to produce granulated powder. The granulated powder was then placed in a 20φ mold and pressurized with a pressure of 100 MPa from both above and below to form a coin shape to obtain a molded body. The molded body was fired at 1285°C for 6 hours, and then reduced at 800°C for 6 hours under a nitrogen gas flow containing 4% hydrogen gas to obtain support layer 1. After reduction, nickel oxide in the molded body is reduced to produce Ni-3YSZ. The completion of the reduction was confirmed by weighing the molded body before and after reduction. The volume ratio of Ni to 3YSZ in support layer 1 after reduction is 39:41.

[0044] [Example 2] The support layer 1 was formed in the same manner as in Example 1, except that the molded body was fired at 1300°C.

[0045] [Comparative Example] As Comparative Example 1, support layer 1 was formed in the same manner as in Example 1, except that 8YSZ (TZ-8YS manufactured by Tosoh Corporation) was used instead of 3YSZ and fired at 1350°C. Support layers 1 for Comparative Examples 2, 3, and 4 were formed in the same manner as in Example 1, except that the firing temperatures were 1250°C, 1270°C, and 1315°C. Furthermore, support layer 1 for Comparative Example 5 was formed in the same manner as in Example 1, except that 3YSZ powder (3Y-LD manufactured by Tosoh Corporation) was used and fired at 1350°C.

[0046] The void ratio was calculated for each of the support layers 1 prepared in the examples and comparative examples. The void ratio was determined from the geometry and weight of support layer 1. The geometry was calculated by measuring the thickness and diameter of support layer 1 at multiple points and using the average value.

[0047] Furthermore, a ring-on-ring test was performed according to ASTM standard C1499 to determine the fracture stress σ of support layer 1 in the examples and comparative examples. fIt was calculated based on Equation 1. The test is performed by placing the specimen between the support ring and the load ring, applying a load from the load ring to the specimen, and measuring the load and displacement until the specimen is broken. Here, F in Equation 1 is the measured load (N) at the time of damage of the support layer 1, D, D S , D L are the diameters of the support layer 1, the support ring, and the load ring (mm), respectively, ν is the Poisson's ratio, and h is the sample thickness (mm). ν = 0.3 was substituted into Equation 1. The thickness of the support layer 1 was the average thickness at four measurement points. [Number]

[0048] Table 1 is a table showing the average fracture stress and its standard deviation, average porosity, and number of measurement samples of the support layer 1 according to the examples and comparative examples. Also, FIG. 2 is a graph in which the average porosity is plotted on the horizontal axis and the fracture strength is plotted on the vertical axis for each of the examples and comparative examples. The porosity according to the examples and comparative examples is affected by the degree of shrinkage of the molded body during firing and the reduction of nickel oxide, and is different for each. On the other hand, as shown in FIG. 2, it can be seen from the plots of Examples 1 to 2 and Comparative Examples 2 to 5 made of Ni-3YSZ with only the firing temperature being different that there is a correlation between the porosity and the fracture stress. Since the porosity can be adjusted by adding a pore-forming material when the support layer 1 is created, even if Comparative Example 1 and Examples 1 to 2 are compared at the same porosity, it can be seen that the fracture stress of Examples 1 to 2 is greater than the fracture stress of Comparative Example 1. Also, except for Comparative Example 3, the support layer 1 made of Ni-3YSZ had a greater fracture stress than the support layer 1 made of Ni-8YSZ (Comparative Example 1).

[0049] Also, when comparing Comparative Example 1 fired at 1350 °C using 8YSZ and Comparative Example 5 fired at 1350 °C using 3YSZ, the fracture stress of Comparative Example 5 is greater. Therefore, it can be seen from Examples 1 to 2 and Comparative Examples 2 to 5 that the fracture stress of Ni-3YSZ increases as the firing temperature increases. [Table 1]

[0050] Next, for Comparative Examples 2 and 5, X-ray diffraction measurements were performed on the polished surface of support layer 1 before and after hydrothermal degradation treatment to determine the proportion of monoclinic crystals in 3YSZ. Hydrothermal degradation treatment was performed by leaving support layer 1 in saturated water vapor at 140°C for 48 hours. This is a condition that allows hydrothermal degradation to proceed sufficiently, and as an alternative hydrothermal degradation treatment, support layer 1 may also be immersed in hot water at 140°C for 48 hours. Table 2 shows the proportion of monoclinic crystals in zirconia before and after hydrothermal degradation treatment. As shown in Table 2, it can be seen that no phase change to monoclinic crystals occurs when the firing temperature is 1250°C. Furthermore, when the firing temperature was 1350°C, the proportion of monoclinic crystals after hydrothermal degradation treatment was 13.9%. From this, it is suggested that when the firing temperature is lower than 1350°C, a phase change to monoclinic crystals is unlikely to occur even under high water vapor partial pressure in the range of 100-400°C. [Table 2]

[0051] Next, the fracture stress after hydrothermal degradation treatment was measured and calculated for each of Examples 1-2 and Comparative Examples 2-5, and the fracture stresses of Ni-3YSZ with different firing temperatures were compared. Figure 3 shows the fracture stress before hydrothermal degradation treatment, and Figure 4 shows the fracture stress after hydrothermal degradation treatment. As shown in Figures 3 and 4, Comparative Examples 2-3 and Examples 1-2, where the firing temperature was 1300°C or lower, showed a small change in fracture stress of 15% or less after hydrothermal degradation treatment, whereas Comparative Examples 4-5, where the firing temperature exceeded 1300°C, showed a large change in fracture stress of 15% or more after hydrothermal degradation treatment, indicating a decrease in the strength of the support layer 1. From this, it can be seen that when the firing temperature exceeds 1300°C, hydrothermal degradation occurs, and cracks etc. occur in the support layer 1. On the other hand, as in Comparative Examples 2-3, when the firing temperature is lower than 1285°C, sintering is insufficient and the fracture stress is low. Therefore, it was suggested that by firing at a temperature between 1285°C and 1300°C, a support layer 1 can be obtained that can improve strength while suppressing hydrothermal degradation.

[0052] Furthermore, to compare the fracture stress of support layer 1 made of Ni-8YSZ and support layer 1 made of Ni-3YSZ at the same porosity, the fracture stress of support layer 1 made of Ni-8YSZ with a porosity of 27.8% was calculated. The fracture stress was calculated by first calculating the fracture stress of support layer 1 for Comparative Example 6, which was prepared under the same conditions as Comparative Example 1 except that an acrylic porosity-forming material was mixed in with Comparative Example 1. Then, a correlation formula between fracture stress and porosity was obtained from the fracture stress and porosity values ​​for Comparative Example 1 and Comparative Example 6, and the fracture stress was calculated by substituting a porosity of 27.8% into that correlation formula. As shown in Table 3, when compared at the same porosity, it was found that support layer 1 made of Ni-3YSZ according to Example 1 had a higher fracture stress than support layer 1 made of Ni-8YSZ, even after hydrothermal degradation treatment. Therefore, by firing the support layer 1, which is made of Ni-3YSZ, at 1285°C to 1300°C, it is possible to suppress hydrothermal degradation and produce a solid oxide cell E with high strength, even when using a solid oxide cell E under conditions where hydrothermal degradation occurs. [Table 3]

[0053] The configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. Furthermore, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto and can be modified as appropriate without departing from the object of the present invention. [Industrial applicability]

[0054] This invention can be used in a method for manufacturing a solid oxide cell in which an electrode layer is formed on a support layer. [Explanation of Symbols]

[0055] 1:Support layer 2: Electrode layer 3: Electrolyte layer 4: Counter electrode layer E: Solid oxide cell

Claims

1. NiO and 3 mol% Y ２ O ３ ZrO containing ２ An electrode layer formation step, in which an electrode layer is formed on a support layer including, The electrolyte layer formation step involves forming an electrolyte layer on the electrode layer, A method for manufacturing a solid oxide cell, comprising a firing step of firing at least the support layer at 1280°C or higher and 1300°C or lower.

2. The method for manufacturing a solid oxide cell according to claim 1, further comprising the step of forming a counter electrode layer on the electrolyte layer.

3. The method for manufacturing a solid oxide cell according to claim 2, wherein the firing step is performed between the electrolyte layer formation step and the counter electrode layer formation step.

4. A method for producing a solid oxide cell according to claim 1, further comprising a reduction step of reducing at least the support layer after the firing step.

5. A method for producing a solid oxide cell according to any one of claims 1 to 4, wherein the thickness of the electrolyte layer is 50 μm or less.

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