JP6779352B2 - Method for manufacturing metal-supported electrochemical element, solid oxide fuel cell and metal-supported electrochemical element - Google Patents

Description

The present invention includes a metal substrate as a support, an electrode layer formed on the metal substrate, a buffer layer formed on the electrode layer, and an electrolyte layer formed on the buffer layer. The present invention relates to a metal-supported electrochemical element and a solid oxide-type fuel cell having at least the above, and a method for manufacturing the metal-supported electrochemical element.

In the conventional electrolyte-supported solid oxide fuel cell (hereinafter referred to as “SOFC”) and the electrode-supported SOFC, in order to obtain an electrolyte layer having a high density, airtightness and gas barrier property, a high temperature (for example, 1400 ° C.) is obtained. ) Is fired. In recent years, in order to improve robustness, a metal-supported SOFC that supports a fuel electrode, an air electrode, and an electrolyte layer on a metal substrate has been developed.

Patent Document 1 discloses a metal-supported SOFC in which a thin-film fuel electrode layer, an electrolyte layer, and an air electrode layer are laminated in this order on a porous metal substrate. In this SOFC manufacturing process, the material of the electrolyte layer is applied on the fuel electrode layer, dried, and then pressed. After that, sintering is performed to form a dense electrolyte layer.

Japanese Unexamined Patent Publication No. 2008-234927

However, even the electrolyte layer obtained by the method of Patent Document 1 has insufficient performance, and a sufficient open circuit voltage (OCV) has not been obtained, and there is a need for improvement. On the other hand, if high-temperature heat treatment is performed during the production of a metal-supported SOFC, the metal substrate as a support deteriorates, and the diffusion of elements such as Cr from the metal substrate adversely affects the components (electrode layer, electrolyte layer) of the SOFC. In some cases, the performance and durability of SOFC may decrease. Therefore, heat treatment at a low temperature is desired. However, if the heat treatment temperature during manufacturing is lowered, it becomes difficult to obtain a high-quality electrode layer or electrolyte layer. For example, if the firing temperature of the electrolyte layer is lowered, it becomes difficult to obtain an electrolyte layer that is dense and has high airtightness and gas barrier properties.

Further, in the conventional electrode-supported SOFC, electrolyte-supported SOFC, etc., the anode electrode layer of cermet and the electrolyte layer of ceramics are co-sintered, for example. In this case, since each layer contracts together with the support at the same time, the binding force that each layer on the support receives from the support is not so large. However, in a metal-supported SOFC using a metal substrate as a support, the electrolyte layer and the electrode layer are formed on the metal substrate because the shrinkage rate at the time of firing differs between the metal substrate and the electrolyte layer or the electrode layer. At that time, the binding force that the electrolyte layer and the electrode layer receive from the metal substrate becomes large. Therefore, a porous electrode layer that is highly resistant to various stresses such as heat shock and has excellent performance, reliability, and stability, and an electrolyte layer that is dense and has high airtightness and gas barrier properties are formed on a metal substrate. It was very difficult to form in.

That is, a metal-supported SOFC having a porous electrode layer having excellent performance, reliability, and stability and an electrolyte layer having a dense airtightness and high gas barrier property on the metal substrate suppresses damage to the metal substrate. It is very difficult to obtain it in a possible temperature range of, for example, 1100 ° C. or lower, and in particular, it is extremely difficult to use a zirconia-based material such as YSZ, which has a high temperature range required for sintering, as an electrolyte. ..

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to have a porous electrode layer and an electrolyte layer having a dense, airtightness and high gas barrier property on a metal substrate, and its performance, reliability and stability. The purpose is to realize a metal-supported electrochemical element having excellent properties.

The characteristic configuration of the metal-supported electrochemical element according to the present invention for achieving the above object is formed on a metal substrate as a support having a plurality of through holes extending from the front side to the back side and the metal substrate. It has at least an electrode layer, a buffer layer formed on the electrode layer, and an electrolyte layer formed on the buffer layer, the electrode layer is porous, and the electrolyte layer is dense. the density of the buffer layer is greater than the density of the said electrode layer, and the rather smaller than density of the electrolyte layer, the thickness of the buffer layer is in point is 10μm or less.

After diligent studies, the inventors can stably form a porous electrode layer and a dense electrolyte layer on a metal substrate by providing a buffer layer between the porous electrode layer and the dense electrolyte layer. It has been found that by introducing a buffer layer between the electrode layer and the electrolyte layer, various stresses due to heat shock and the like can be relaxed, and an element having excellent reliability and stability can be formed. That is, according to the above-mentioned characteristic configuration, by making the density of the buffer layer larger than the density of the electrode layer and smaller than the density of the electrolyte layer, an electrolyte layer having a high density, airtightness and gas barrier property can be obtained. It can be formed stably. Further, according to such a configuration, a porous electrode layer that does not impair the gas diffusivity required for the electrode layer and a dense electrolyte layer having ionic conductivity and gas barrier properties required for the electrolyte layer are formed on a metal substrate. It can be stably formed on the top. The density is a ratio of the material constituting the layer to the space, and can be expressed as (1-vacancy ratio), and is equivalent to the relative density.
According to the above characteristic configuration, since the thickness of the buffer layer is 10 μm or less, it is possible to obtain an element having high electrochemical characteristics in which an increase in internal resistance is suppressed.
According to the above-mentioned characteristic configuration, since the metal substrate has a plurality of through holes extending from the front side to the back side, gas can be supplied to the electrode layer through the plurality of through holes. Performance can be further improved.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that the buffer layer contains a ceria-based material.

According to the above characteristic configuration, since the buffer layer contains a ceria-based material, the buffer layer has mixed conductivity. As a result, an element having high electrochemical performance can be realized.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that the electrolyte layer contains stabilized zirconia.

According to the above-mentioned characteristic configuration, since the electrolyte layer contains stabilized zirconia, it is possible to realize an element capable of exhibiting high electrochemical performance even in a relatively high temperature range of, for example, 600 ° C. or higher, preferably 650 ° C. or higher.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that the thickness of the buffer layer is 4 μm or more.

According to the above-mentioned feature configuration, a buffer layer having high mechanical strength can be stably obtained even by an inexpensive method such as screen printing.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that the density of the buffer layer is 50% or more and less than 98%.

If the buffer layer has a density of 50% or more and less than 98%, it can be stably formed by an inexpensive method such as screen printing. In addition, it is possible to realize an element having high mechanical strength capable of alleviating various stresses such as heat shock, and it is also possible to realize an element capable of exhibiting high electrochemical characteristics. If the density of the buffer layer is too high, the density of the electrode layer and the buffer layer will be significantly different, and it will be difficult to obtain the effect of relaxing the stress between the electrode layer and the buffer layer. On the other hand, if the density of the buffer layer is too small, the density of the buffer layer and the electrolyte layer are significantly different, and it becomes difficult to obtain the effect of relaxing the stress between the buffer layer and the electrolyte layer. When the density of the buffer layer is 80% or more, the effect of relaxing the stress between the buffer layer and the electrolyte layer can be further increased, which is more preferable. When the density of the buffer layer is less than 96%, the effect of relaxing the stress between the buffer layer and the electrode layer can be further increased, which is more preferable.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that a part of the electrolyte layer includes a dense electrolyte layer having a density of 98% or more.

According to the above characteristic configuration, since the dense electrolytic layer is included in a part of the electrolyte layer, even if there are some defects inside the electrolyte layer, the entire electrolyte layer is in a state of high airtightness and gas barrier property. can do. Such an electrolyte layer can be formed by an inexpensive method even in a temperature range where damage to the metal substrate can be suppressed (for example, 1100 ° C. or lower), and it is easy to form an electrolyte layer capable of exhibiting high electrochemical performance. That is, such an electrolyte layer is suitable for a metal-supported electrochemical device.

Another characteristic configuration of the metal-supported electrochemical element according to the present invention is that it has a diffusion suppression layer that suppresses the diffusion of Cr from the metal substrate to the electrode layer.

According to the above-mentioned feature configuration, it is possible to suppress the deterioration of the performance of the device due to the diffusion of Cr in the electrode layer.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that the diffusion suppression layer is a metal oxide layer formed on the surface of the metal substrate.

According to the above-mentioned feature configuration, the process of forming the diffusion suppression layer can be simplified, and the device can be manufactured at low cost.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that the through hole is formed inside the region where the electrolyte layer is formed in the metal substrate.

According to the above characteristic configuration, the region where the through holes are formed is covered with the dense, airtight and highly gas-barrier electrolyte layer, so that the area where the through holes are formed is covered separately to prevent gas from leaking to other places such as packing and sealing. The structure of is unnecessary. That is, it is possible to suppress an increase in the manufacturing cost of the device.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that the through hole is formed inside the region where the electrode layer is formed in the metal substrate.

According to the above-mentioned characteristic configuration, the gas supplied through the through hole can be efficiently supplied to the electrode layer, which is suitable as the configuration of the electrochemical element.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that a counter electrode layer, which is a counter electrode of the electrode layer, is provided on the electrolyte layer.

According to the above characteristic configuration, as described above, on the metal substrate, a porous electrode layer, a buffer layer having a denser density than the electrode layer and smaller than the electrolyte layer, and a dense, airtight and gas barrier property are high. It has an electrolyte layer and a counter electrode layer, and the electrode layer and the counter electrode layer can realize an electrochemical element that can be used as an electrochemical element. That is, it is possible to realize a metal-supported electrochemical element having high performance, excellent stability and reliability, and capable of integrally carrying out an anode reaction and a cathode reaction.

Another characteristic configuration of the metal-supported electrochemical device according to the present invention is that it has a reaction prevention layer formed between the electrolyte layer and the counter electrode layer.

According to the above-mentioned characteristic configuration, it is possible to prevent a reaction between the component of the electrolyte layer and the component of the counter electrode layer and realize an element having excellent long-term durability.

The characteristic configuration of the solid oxide fuel cell according to the present invention for achieving the above object is that it has the above-mentioned metal-supported electrochemical element and can be operated in a temperature range of 600 ° C. or higher and 750 ° C. or lower during rated operation. It is in the point of being done.

According to the above characteristic configuration, since the fuel cell is operated in the temperature range of 600 ° C. or higher and 750 ° C. or lower during the rated operation, the performance of the fuel cell is suppressed by suppressing the deterioration of the metal-supported electrochemical element while exhibiting high power generation performance. Can be maintained for a long period of time. It is more preferable that the fuel cell system can be operated in a temperature range of 650 ° C. or higher and 750 ° C. or lower during rated operation because the power generation performance of the fuel cell system can be further improved.

The characteristic configuration of the method for manufacturing a metal-supported electrochemical element according to the present invention for achieving the above object is an electrode layer forming step of forming a porous electrode layer on a metal substrate as a support, and the electrode. It has a buffer layer forming step of forming a buffer layer on the layer and an electrolyte layer forming step of forming a dense electrolyte layer on the buffer layer.
The density of the buffer layer is larger than that of the electrode layer and smaller than that of the electrolyte layer.
The point is that the electrode layer forming step, the buffer layer forming step, and the electrolyte layer forming step are performed at 1100 ° C. or lower.

According to the above-mentioned characteristic configuration, the metal substrate has a porous electrode layer, a buffer layer formed on the electrode layer, and an electrolyte layer formed on the buffer layer. By making the density of the electrode layer larger than that of the electrode layer and smaller than that of the electrolyte layer, a porous electrode layer and a dense electrolyte layer having high airtightness and gas barrier property are stabilized on the metal substrate. Can be formed. Further, since the electrode layer forming step, the buffer layer forming step, and the electrolyte forming step are performed at 1100 ° C. or lower, deterioration of the metal substrate can be suppressed and a high quality element can be obtained. Further, if necessary, when the manufacturing process of the metal-supported electrochemical element includes a counter electrode layer forming step for forming the counter electrode layer, a reaction preventing layer forming step for forming the reaction preventing layer, and the like, those The step is preferably carried out at 1100 ° C. or lower. By doing so, it is possible to suppress deterioration of the metal substrate and obtain a high-quality element.

Schematic diagram showing the configuration of a metal-supported electrochemical device Schematic diagram showing the configuration of a metal-supported electrochemical device Schematic diagram showing the configuration of a metal-supported electrochemical device Schematic diagram showing the configuration of a metal-supported electrochemical device Electron micrograph of cross section of metal-supported electrochemical device Electron micrograph of cross section of metal-supported electrochemical device

(First Embodiment)
Hereinafter, a method for manufacturing the metal-supported electrochemical element E, the solid oxide fuel cell (SOFC), and the metal-supported electrochemical element E will be described with reference to FIGS. 1 and 2. The metal-supported electrochemical element E is used, for example, as a component of a solid oxide fuel cell that generates electricity by being supplied with a fuel gas containing hydrogen and air. Hereinafter, when expressing the positional relationship of the layers, for example, the side of the electrolyte layer 4 may be referred to as “upper” or “upper” and the side of the electrode layer 2 may be referred to as “lower” or “lower” when viewed from the buffer layer 3. is there. Further, the surface of the metal substrate 1 on which the electrode layer 2 is formed may be referred to as a "front side" and the opposite surface may be referred to as a "back side".

(Metal support type electrochemical element)
As shown in FIG. 1, the metal-supported electrochemical element E includes a metal substrate 1 as a support, an electrode layer 2 formed on the metal substrate 1, and a buffer layer formed on the electrode layer 2. It has at least 3 and an electrolyte layer 4 formed on the buffer layer 3. The metal-supported electrochemical element E further has a reaction prevention layer 5 formed on the electrolyte layer 4 and a counter electrode layer 6 formed on the reaction prevention layer 5. The counter electrode layer 6 is formed on the electrolyte layer 4, and the reaction prevention layer 5 is formed between the electrolyte layer 4 and the counter electrode layer 6. The electrode layer 2 is porous, and the electrolyte layer 4 is dense. The density of the buffer layer 3 is larger than that of the electrode layer 2 and smaller than that of the electrolyte layer 4. The density is a ratio of the material constituting the layer to the space, and can be expressed as (1-vacancy ratio). It is also equivalent to the relative density.

(Metal substrate)
The metal substrate 1 plays a role as a support that supports the electrode layer 2, the buffer layer 3, the electrolyte layer 4, and the like to maintain the strength of the metal-supported electrochemical element E. As the material of the metal substrate 1, a material having excellent electron conductivity, heat resistance, oxidation resistance and corrosion resistance is used. For example, ferrite stainless steel, austenitic stainless steel, nickel alloy and the like are used. In particular, an alloy containing chromium is preferably used.

The metal substrate 1 has a plurality of through holes 1a provided so as to penetrate the front surface and the back surface. For example, the through hole 1a can be provided in the metal substrate 1 by laser processing or the like. The through hole 1a has a function of allowing gas to permeate from the back surface to the front surface of the metal substrate 1. It is also possible to use a porous metal in order to give the metal substrate 1 gas permeability.

A metal oxide layer 1b as a diffusion suppressing layer is provided on the surface of the metal substrate 1. That is, a diffusion suppression layer is formed between the metal substrate 1 and the electrode layer 2 described later. The metal oxide layer 1b is provided not only on the surface exposed to the outside of the metal substrate 1, but also on the contact surface (interface) with the electrode layer 2 and the inner surface of the through hole 1a. The metal oxide layer 1b can suppress elemental mutual diffusion between the metal substrate 1 and the electrode layer 2. For example, when ferrite stainless steel is used as the metal substrate 1, the metal oxide layer 1b is mainly a chromium oxide. Then, the metal oxide layer 1b containing chromium oxide as a main component suppresses the diffusion of chromium atoms and the like of the metal substrate 1 to the electrode layer 2 and the electrolyte layer 4. The thickness of the metal oxide layer 1b is preferably on the submicron order. Further, for example, it is preferable that the average thickness is about 0.3 μm or more and 0.7 μm or less. The minimum thickness is preferably about 0.1 μm or more. Further, the maximum thickness is preferably about 1.1 μm or less.

When a ferritic stainless steel material is used as the metal substrate 1, the coefficient of thermal expansion is similar to YSZ (yttria-stabilized zirconia) and GDC (gadolinium-doped ceria, also called CGO) used as materials for the electrode layer 2 and the electrolyte layer 4. Is close. Therefore, the metal-supported electrochemical element E is less likely to be damaged even when the low-temperature and high-temperature temperature cycles are repeated. Therefore, it is preferable because the metal-supported electrochemical element E having excellent long-term durability can be realized.

(Electrode layer)
As shown in FIG. 1, the electrode layer 2 is provided in a thin film state on the front surface of the metal substrate 1 and in a region larger than the region where the through hole 1a is provided. The entire region provided with the through hole 1a is covered with the electrode layer 2. That is, the through hole 1a is formed inside the region of the metal substrate 1 where the electrode layer 2 is formed. In other words, all the through holes 1a are provided facing the electrode layer 2.

As the material of the electrode layer 2, for example, a cermet material such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO ₂ , or Cu-CeO ₂ can be used. In these examples, GDC, YSZ, and CeO ₂ can be referred to as cermet aggregates. The electrode layer 2 is preferably formed by a low temperature firing method (for example, a wet method using a firing treatment in a low temperature range that does not perform a firing treatment in a high temperature range higher than 1100 ° C.), an aerosol deposition method, a thermal spraying method, or the like. .. These processes that can be used in the low temperature region give a good electrode layer 2 without using firing in a high temperature region higher than, for example, 1100 ° C. Therefore, it is preferable because the metal substrate 1 is not damaged, the mutual diffusion of elements between the metal substrate 1 and the electrode layer 2 can be suppressed, and an electrochemical element having excellent durability can be realized. Further, it is more preferable to use the low temperature firing method because the handling of the raw material becomes easy.

The electrode layer 2 has a plurality of pores inside and on the surface in order to have gas permeability. That is, the electrode layer 2 is formed as a porous layer. The electrode layer 2 is formed so that its density is, for example, 30% or more and less than 80%. As the size of the pores, a size suitable for the smooth reaction to proceed when the electrochemical reaction is carried out can be appropriately selected.

(Cushioning layer)
As shown in FIG. 1, the buffer layer 3 is formed on the electrode layer 2 in a thin film state while covering the electrode layer 2. Examples of the material of the buffer layer 3 include YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), and SDC (samarium-doped ceria). Ceria) and the like can be used. In particular, ceria-based ceramics are preferably used.

The buffer layer 3 is preferably formed by a low temperature firing method (for example, a wet method using a firing treatment in a low temperature range that does not perform a firing treatment in a high temperature range higher than 1100 ° C.), an aerosol deposition method, a thermal spraying method, or the like. These film formation processes that can be used in the low temperature region provide the buffer layer 3 without using firing in a high temperature region higher than, for example, 1100 ° C. Therefore, elemental mutual diffusion between the metal substrate 1 and the electrode layer 2 can be suppressed without damaging the metal substrate 1, and a metal-supported electrochemical element E having excellent durability can be realized. Further, it is more preferable to use the low temperature firing method because the handling of the raw material becomes easy.

The buffer layer 3 has the following configurations and features.

First, the buffer layer 3 is formed so that its density is larger than that of the electrode layer 2 and smaller than that of the electrolyte layer 4. For example, the density of the electrode layer 2 is 30% or more and less than 80%, the density of the buffer layer 3 is 50% or more and less than 98%, and the density of the electrolyte layer 4 is 96% or more. Each layer is formed so that the density of the electrode layer 2 is larger than that of the electrode layer 2 and smaller than that of the electrolyte layer 4. The density (relative density) of each of the buffer layer 3, the electrolyte layer 4, and the electrode layer 2 is determined by the respective materials and the conditions at the time of formation. For example, the density of the buffer layer 3, the electrolyte layer 4, and the electrode layer 2 to be formed changes depending on various formation conditions such as the particle size, shape, composition, and firing temperature of the material powder. That is, by appropriately adjusting these conditions, the density of the buffer layer 3, the electrolyte layer 4, and the electrode layer 2 can be adjusted.

Further, the buffer layer 3 is formed so that its thickness is within a predetermined range by appropriately setting the form of the material, the conditions at the time of formation, and the like. Specifically, the buffer layer 3 is preferably formed so that its thickness is 4 μm or more, and preferably 10 μm or less.

In order to form a dense electrolyte layer 4 on the porous electrode layer 2, the buffer layer 3 continuously connects the two to relieve various stresses applied during the manufacture of the device and the operation of the device. It is arranged between the two as a layer having a buffering effect. Therefore, the buffer layer 3 is intentionally formed so that the density is smaller than that of the electrolyte layer 4. Further, the buffer layer 3 is intentionally formed so that the density is higher than that of the electrode layer 2. As a result, the buffer layer 3 absorbs and relaxes various stresses between the layers even when the porous electrode layer 2 and the dense electrolyte layer 4 are formed on the metal substrate, and is a metal support type. It also has the effect of enhancing the performance, reliability, and stability of the electrochemical element E.

The buffer layer 3 preferably has oxygen ion (oxide ion) conductivity. Further, it is more preferable to have mixed conductivity of oxygen ions (oxide ions) and electrons. The buffer layer 3 having these properties is suitable for application to the metal-supported electrochemical element E.

The buffer layer 3 preferably does not contain a catalytic metal component such as Ni or Cu. This is because it becomes difficult to obtain the desired buffer layer 3 if a catalyst metal component such as Ni or Cu is contained.

(Electrolyte layer)
As shown in FIG. 1, the electrolyte layer 4 is formed on the buffer layer 3 in a thin film state while covering the electrode layer 2 and the buffer layer 3. Specifically, as shown in FIG. 1, the electrolyte layer 4 is provided over (straddling) the buffer layer 3 and the metal substrate 1. By forming the electrolyte layer 4 in this way and joining the electrolyte layer 4 to the metal substrate 1, the overall electrochemical element can be made excellent in robustness.

Further, as shown in FIG. 1, the electrolyte layer 4 is provided on the front surface of the metal substrate 1 in a region larger than the region where the through hole 1a is provided. That is, the through hole 1a is formed inside the region where the electrolyte layer 4 is formed in the metal substrate 1.

Further, around the electrolyte layer 4, gas leakage from the electrode layer 2 and the buffer layer 3 can be suppressed. To explain, when the metal-supported electrochemical element E is used as a component of the SOFC, gas is supplied from the back side of the metal substrate 1 to the electrode layer 2 through the through hole 1a when the SOFC is operated. At the portion where the electrolyte layer 4 is in contact with the metal substrate 1, gas leakage can be suppressed without providing a separate member such as a gasket. In the present embodiment, the electrolyte layer 4 covers the entire periphery of the electrode layer 2, but the electrolyte layer 4 may be provided above the electrode layer 2 and the buffer layer 3, and a gasket or the like may be provided around the electrode layer 2.

Materials of the electrolyte layer 4 include YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), and SDC (samarium-doped ceria). Etc. can be used. In particular, zirconia-based ceramics are preferably used. When the electrolyte layer 4 is made of zirconia-based ceramics, the operating temperature of the SOFC using the metal-supported electrochemical element E can be made higher than that of ceria-based ceramics. For example, when the metal-supported electrochemical element E is used for SOFC, a material such as YSZ that can exhibit high electrolyte performance even in a high temperature range of about 650 ° C. or higher is used as the material of the electrolyte layer 4, and city gas or city gas is used as the raw material of the system. If a system configuration is made in which a hydrocarbon-based raw material such as LPG is used and the raw material is used as the anode gas of SOFC by steam reforming or the like, the heat generated in the cell stack of SOFC is used for reforming the raw fuel gas with high efficiency. SOFC system can be constructed.

The electrolyte layer 4 is provided by a low temperature firing method (for example, a wet method using a firing treatment in a low temperature range that does not perform a firing treatment in a high temperature range of 1100 ° C. or higher), an aerosol deposition method, a thermal spraying method, a sputtering method, or a pulse laser deposition method. It is preferable to form it by such means. By these film forming processes that can be used in a low temperature range, an electrolyte layer 4 that is dense and has high airtightness and gas barrier property can be obtained without using firing in a high temperature range of, for example, 1100 ° C. or higher. Therefore, damage to the metal substrate 1 can be suppressed, element mutual diffusion between the metal substrate 1 and the electrode layer 2 can be suppressed, and a metal-supported electrochemical element E having excellent performance and durability can be realized. In particular, it is preferable to use a low-temperature firing method, an aerosol deposition method, a thermal spraying method, or the like because a low-cost element can be realized. Further, it is more preferable to use the aerosol deposition method because an electrolyte layer having a high density, airtightness and gas barrier property can be easily obtained in a low temperature range.

The electrolyte layer 4 is densely configured in order to shield gas leaks from the anode gas and the cathode gas and to exhibit high ionic conductivity. The density of the electrolyte layer 4 is preferably 96% or more, and more preferably 98% or more. When the electrolyte layer 4 is a uniform layer, its density is preferably 96% or more, and more preferably 98% or more. When the electrolyte layer 4 is composed of a plurality of layers, it is preferable that at least a part of the electrolyte layer 4 contains a layer having a density of 98% or more (dense electrolyte layer), which is 99%. It is more preferable to include the above-mentioned layer (dense electrolyte layer). When such a dense electrolyte layer is contained as a part of the electrolyte layer, even when the electrolyte layer is formed in a plurality of layers, an electrolyte layer having a high density, airtightness and gas barrier property is formed. This is because it can be made easier.

(Reaction prevention layer)
The reaction prevention layer 5 is a layer formed in a thin film on the electrolyte layer 4. The material of the reaction prevention layer 5 may be any material that can prevent the reaction between the component of the electrolyte layer 4 and the component of the counter electrode layer 6. For example, a ceria-based material or the like is used. By introducing the reaction prevention layer 5 between the electrolyte layer 4 and the counter electrode layer 6, the reaction between the constituent material of the counter electrode layer 6 and the constituent material of the electrolyte layer 4 is effectively suppressed, and the metal support type electricity is used. The long-term stability of the performance of the chemical element E can be improved. When the reaction prevention layer 5 is formed by appropriately using a method capable of forming at a treatment temperature of 1100 ° C. or lower, damage to the metal substrate 1 is suppressed, and elemental mutual diffusion between the metal substrate 1 and the electrode layer 2 is suppressed. It is preferable because it can realize a metal-supported electrochemical element E having excellent performance and durability. For example, a wet method (low temperature firing method) by printing or spraying, an aerosol deposition method, a thermal spraying method, a sputtering method, a pulse laser deposition method, or the like can be appropriately used. In particular, it is preferable to use a low-temperature firing method, an aerosol deposition method, a thermal spraying method, or the like because a low-cost element can be realized. Further, it is more preferable to use the low temperature firing method because the handling of the raw material becomes easy.

(Counter electrode layer)
The counter electrode layer 6 is a layer formed in a thin film on the electrolyte layer 4 or the reaction prevention layer 5. As the material of the counter electrode layer 6, for example, a composite oxide such as LSCF or LSM can be used. When the counter electrode layer 6 is formed by appropriately using a method capable of forming at a treatment temperature of 1100 ° C. or lower, damage to the metal substrate 1 can be suppressed, and element mutual diffusion between the metal substrate 1 and the electrode layer 2 can be suppressed. It is preferable because the metal-supported electrochemical element E having excellent performance and durability can be realized. For example, a wet method (low temperature firing method) by printing or spraying, an aerosol deposition method, a thermal spraying method, a sputtering method, a pulse laser deposition method, or the like can be appropriately used. In particular, it is preferable to use a low-temperature firing method, an aerosol deposition method, a thermal spraying method, or the like because a low-cost element can be realized. Further, it is more preferable to use the low temperature firing method because the handling of the raw material becomes easy.

(Solid oxide fuel cell)
By configuring the metal-supported electrochemical element E as described above, the metal-supported electrochemical element E can be used as a power generation cell of a solid oxide fuel cell. For example, a fuel gas containing hydrogen is supplied to the electrode layer 2 from the back surface of the metal substrate 1 through the through hole 1a, and air is supplied to the counter electrode layer 6 which is the counter electrode of the electrode layer 2, for example, 600 ° C. or higher and 750 ° C. or higher. Operate at a temperature below ° C. Then, in the counter electrode layer 6, oxygen O ₂ contained in the air reacts with the electron e ⁻ to generate oxygen ion O ^2- . The oxygen ion O ^2- moves to the electrode layer 2 through the electrolyte layer 4. In the electrode layer 2, reacts hydrogen H ₂ contained in the supplied fuel gas with ² oxygen ions O, water between H ₂ O and electrons e ^- are generated. By the above reaction, an electromotive force is generated between the electrode layer 2 and the counter electrode layer 6. In this case, the electrode layer 2 functions as a fuel electrode (anode) of the SOFC, and the counter electrode layer 6 functions as an air electrode (cathode).

(Manufacturing method of metal-supported electrochemical element)
Next, a method for manufacturing the metal-supported electrochemical element E will be described.

(Electrode layer formation step)
In the electrode layer forming step, the electrode layer 2 is formed in a thin film state in a region wider than the region provided with the through hole 1a on the front surface of the metal substrate 1. The through hole of the metal substrate 1 can be provided by laser processing or the like. As described above, the electrode layer 2 can be formed by a method such as a low temperature firing method (a wet method in which a firing treatment is performed in a low temperature range of 1100 ° C. or lower), an aerosol deposition method, or a thermal spraying method. Regardless of which method is used, it is desirable to carry out the process at a temperature of 1100 ° C. or lower in order to suppress deterioration of the metal substrate 1.

When the electrode layer forming step is performed by the low-temperature firing method, it is specifically performed as in the following example. First, the material powder of the electrode layer 2 and the solvent are mixed to prepare a material paste, which is applied to the front surface of the metal substrate 1 and fired at 800 ° C to 1100 ° C.

(Diffusion suppression layer formation step)
During the firing step in the electrode layer forming step described above, the metal oxide layer 1b (diffusion suppression layer) is formed on the surface of the metal substrate 1. If the firing step includes a firing step in which the firing atmosphere is an atmosphere condition in which the oxygen partial pressure is low, the effect of suppressing mutual diffusion of elements is high, and a high-quality metal oxide layer 1b having a low resistance value (diffusion suppression). It is preferable because a layer) is formed. A separate diffusion suppression layer forming step may be included, including a case where the electrode layer forming step is a method in which firing is not performed (for example, an aerosol deposition method or the like). In either case, it is desirable to carry out the process at a processing temperature of 1100 ° C. or lower, which can suppress damage to the metal substrate 1.

(Cushion layer formation step)
In the buffer layer forming step, the buffer layer 3 is formed in a thin film state on the electrode layer 2 in a form of covering the electrode layer 2. As described above, the buffer layer 3 can be formed by a low-temperature firing method (a wet method in which a firing process is performed in a low temperature range of 1100 ° C. or lower), an aerosol deposition method, a thermal spraying method, or the like. Regardless of which method is used, it is desirable to carry out the process at a temperature of 1100 ° C. or lower in order to suppress deterioration of the metal substrate 1.

When the buffer layer forming step is performed by the low-temperature firing method, it is specifically performed as in the following example. First, the material powder of the buffer layer 3 and the solvent are mixed to prepare a material paste, which is applied on the electrode layer 2 and fired at 800 ° C to 1100 ° C.

(Electrolyte layer formation step)
In the electrolyte layer forming step, the electrolyte layer 4 is formed on the buffer layer 3 in a thin film state while covering the electrode layer 2 and the buffer layer 3. As described above, the electrolyte layer 4 is formed by a low-temperature firing method (wet method in which firing treatment is performed in a low temperature range of 1100 ° C. or lower), an aerosol deposition method, a thermal spraying method, a sputtering method, a pulse laser deposition method, or the like. The method can be used. Regardless of which method is used, it is desirable to carry out the process at a temperature of 1100 ° C. or lower in order to suppress deterioration of the metal substrate 1.

In order to form a high-quality electrolyte layer 4 having high density, airtightness and gas barrier performance in a temperature range of 1100 ° C. or lower, it is desirable to carry out the electrolyte layer forming step by the aerosol deposition method. In that case, the material powder of the electrolyte layer 4 is aerosolized with a transport gas, and the aerosol is injected toward the buffer layer 3 of the metal substrate 1 to form the electrolyte layer 4.

(Reaction prevention layer formation step)
In the reaction prevention layer forming step, the reaction prevention layer 5 is formed on the electrolyte layer 4 in a thin film state. As described above, the reaction prevention layer 5 can be formed by a method such as a low temperature firing method, an aerosol deposition method, a thermal spraying method, a sputtering method, or a pulse laser deposition method. Regardless of which method is used, it is desirable to carry out the process at a temperature of 1100 ° C. or lower in order to suppress deterioration of the metal substrate 1.

(Counter electrode layer forming step)
In the counter electrode layer forming step, the counter electrode layer 6 is formed on the reaction prevention layer 5 in a thin film state. As described above, the counter electrode layer 6 can be formed by a method such as a low temperature firing method, an aerosol deposition method, a thermal spraying method, a sputtering method, or a pulse laser deposition method. Regardless of which method is used, it is desirable to carry out the process at a temperature of 1100 ° C. or lower in order to suppress deterioration of the metal substrate 1.

As described above, the metal-supported electrochemical device E can be manufactured. It is possible to omit the reaction prevention layer forming step, add a step for forming another layer, or stack a plurality of layers of the same type, but in any case, the temperature is 1100 ° C. It is desirable to perform at the following temperatures.

(Second Embodiment)
In the above-described first embodiment, as shown in FIG. 1, both the electrode layer 2 and the electrolyte layer 4 are provided on the front surface of the metal substrate 1 in a region larger than the region where the through hole 1a is provided. .. The entire region provided with the through hole 1a is covered with the electrode layer 2 and the electrolyte layer 4. That is, the through hole 1a is formed inside the region where the electrode layer 2 is formed in the metal substrate 1 and inside the region where the electrolyte layer 4 is formed. In other words, all the through holes 1a are provided facing the electrode layer 2. It is also possible to change this to have the configuration shown in FIG.

In the configuration shown in FIG. 2, the electrode layer 2 is provided in a region smaller than the region where the through hole 1a is provided. The buffer layer 3 and the electrolyte layer 4 are provided in a region larger than the region where the through hole 1a is provided. The entire region provided with the through hole 1a is covered with the buffer layer 3 and the electrolyte layer 4. That is, the through holes 1a are provided inside and outside the region where the electrode layer 2 is formed. Further, the through hole 1a is provided inside the region where the electrolyte layer 4 is formed. In other words, the through hole 1a is provided so as to face both the electrode layer 2 and the buffer layer 3.

(Third Embodiment)
The configuration shown in FIG. 3 is also possible. In the configuration shown in FIG. 3, the electrode layer 2 and the buffer layer 3 are provided in a region smaller than the region in which the through hole 1a is provided. The electrolyte layer 4 is provided in a region larger than the region where the through hole 1a is provided. The entire region provided with the through hole 1a is covered with the electrolyte layer 4. That is, the through holes 1a are provided inside and outside the region where the electrode layer 2 is formed. Through holes 1a are provided inside and outside the region where the buffer layer 3 is formed. Further, the through hole 1a is provided inside the region where the electrolyte layer 4 is formed. In other words, the through hole 1a is provided facing the electrode layer 2, the buffer layer 3, and the electrolyte layer 4.

The configuration shown in FIG. 4 is also possible. In the configuration shown in FIG. 4, the electrode layer 2 and the buffer layer 3 are provided in a region smaller than the region where the through hole 1a is provided. The buffer layer 3 is provided in the region where the electrode layer 2 is provided. The electrolyte layer 4 is provided in a region larger than the region where the through hole 1a is provided. The entire region provided with the through hole 1a is covered with the electrolyte layer 4. That is, the through holes 1a are provided inside and outside the region where the electrode layer 2 is formed. Further, the through hole 1a is provided inside the region where the electrolyte layer 4 is formed. In other words, the through hole 1a is provided facing the electrode layer 2 and the electrolyte layer 4.

(Fourth Embodiment)
In the above embodiment, the metal-supported electrochemical element E is used for the solid oxide fuel cell, but the metal-supported electrochemical element E is a solid oxide-type electrolytic cell or an oxygen sensor using a solid oxide. It can also be used for such purposes.

(Fifth Embodiment)
In the above embodiment, as the material of the electrode layer 2, for example, a cermet material such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO ₂ , Cu-CeO ₂ is used, and the counter electrode layer 6 is formed. As a material, for example, a composite oxide such as LSCF or LSM was used. Then, hydrogen gas was supplied to the electrode layer 2 to serve as a fuel electrode, air was supplied to the counter electrode layer 6 to serve as an air electrode, and the metal-supported electrochemical element E was used as a solid oxide fuel cell. By changing this, it is also possible to configure the metal-supported electrochemical element E so that the electrode layer 2 can be used as an air electrode and the counter electrode layer 6 can be used as a fuel electrode. That is, a composite oxide such as LSCF or LSM is used as the material of the electrode layer 2, and NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO ₂ or Cu as the material of the counter electrode layer 6. -Use a cermet material such as CeO ₂ . In the metal-supported electrochemical element E configured as described above, air is supplied to the electrode layer 2 to form an air electrode, and hydrogen gas is supplied to the counter electrode layer 6 to form a fuel electrode to form a metal-supported electrochemical element. E can be used as a solid oxide fuel cell.

The configurations disclosed in the above embodiments can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction. Further, the embodiments disclosed in the present specification are examples, and the embodiments of the present invention are not limited to these, and can be appropriately modified without departing from the object of the present invention.

Hereinafter, the results of preparing a prototype of the metal-supported electrochemical device E under various conditions and performing various measurements will be described. (Prototype 1: Example)
A metal substrate 1 was prepared by providing a plurality of through holes 1a by laser processing in a region having a radius of 2.5 mm from the center of a circular crosser 22APU metal plate having a thickness of 0.3 mm and a diameter of 25 mm. At this time, the through holes were provided by laser processing so that the diameter of the through holes 1a on the surface of the metal substrate 1 was about 10 to 15 μm.

Next, 60% by weight of NiO powder and 40% by weight of GDC powder were mixed, and an organic binder and an organic solvent were added to prepare a paste. Using the paste, the electrode layer 2 was laminated in a region having a radius of 3 mm from the center of the metal substrate 1. Screen printing was used to form the electrode layer 2.

Next, the metal substrate 1 on which the electrode layer 2 was laminated was fired at 850 ° C. (electrode layer forming step, diffusion suppressing layer forming step).

The amount of He leak of the metal substrate 1 in the state where the electrode layers 2 were laminated in this way was an amount exceeding 50 mL / min · cm ² under a pressure of 0.2 MPa. From this, it can be seen that the electrode layer 2 is formed as a porous layer having low density and gas barrier property.

Next, an organic binder and an organic solvent were added to the fine powder of GDC to prepare a paste. Using the paste, the buffer layer 3 was laminated in a region having a radius of 5 mm from the center of the metal substrate 1 on which the electrode layer 2 was laminated by screen printing.

Next, the metal substrate 1 on which the buffer layer 3 was laminated was fired at 1050 ° C. (buffer layer forming step).

The thickness of the electrode layer 2 obtained in the above steps was about 10 μm, and the thickness of the buffer layer 3 was about 8 μm. Further, the amount of He leak of the metal substrate 1 in the state where the electrode layer 2 and the buffer layer 3 were laminated in this way was 13.5 mL / min · cm ² under a pressure of 0.2 MPa.

Subsequently, 8YSZ (yttria-stabilized zirconia) powder having a mode diameter of about 0.7 μm was aerosolized with dry air at a flow rate of 6 L / min. The aerosol was introduced into a chamber having a pressure of 190 Pa, sprayed onto the buffer layer 3 of the metal substrate 1 in a range of 15 mm × 15 mm so as to cover the buffer layer 3, and the electrolyte layer 4 was laminated. At that time, the metal substrate 1 was not heated and was injected at room temperature (electrolyte layer forming step). In this way, the metal-supported electrochemical element E was formed.

The thickness of the electrolyte layer 4 obtained in the above steps was about 5 μm. When the He leak amount of the metal substrate 1 in the state where the electrode layer 2, the buffer layer 3 and the electrolyte layer 4 were laminated in this way was measured under a pressure of 0.2 MPa, the He leak amount was the lower limit of detection (1.0 mL / It was less than minutes / cm ² ). That is, the amount of He leak in the state where the electrolyte layer 4 is laminated is significantly smaller than the amount of He leak in the state where the buffer layer 3 is laminated, which is below the detection limit. Therefore, it was confirmed that the formed electrolyte layer 4 is dense, has high gas barrier performance, and is of good quality.

Next, an organic binder and an organic solvent were added to the fine powder of GDC to prepare a paste. Using the paste, a reaction prevention layer 5 was formed on the electrolyte layer 4 of the metal-supported electrochemical element E by screen printing.

Then, the metal-supported electrochemical element E on which the reaction prevention layer 5 was formed was fired at 1000 ° C. (reaction prevention layer forming step).

Further, GDC powder and LSCF powder were mixed, and an organic binder and an organic solvent were added to prepare a paste. Using the paste, a counter electrode layer 6 was formed on the reaction prevention layer 5 by screen printing. Finally, the metal-supported electrochemical element E on which the counter electrode layer 6 was formed was fired at 900 ° C. (counter electrode layer forming step) to obtain a metal-supported electrochemical element E.

Regarding the obtained metal-supported electrochemical element E, hydrogen gas was supplied to the electrode layer 2 and air was supplied to the counter electrode layer 6, and the open circuit voltage (OCV) of the solid oxide fuel cell was measured. The result was 1.03 V at 750 ° C.

An electron micrograph of a cross section of the metal-supported electrochemical device E thus obtained is shown in FIG. The electrode layer 2 has a large number of black voids and pores, and the density is relatively low. From the image processing data of FIG. 5, it is estimated that the density of the electrode layer 2 is about 68%. Almost no black voids or vacancies are seen in the electrolyte layer 4, and the electrolyte layer 4 is very dense. From the image processing data of FIG. 5, it is estimated that the density of the electrolyte layer 4 is about 99% or more. On the other hand, since many small black spots are seen in the buffer layer 3, there are small voids and vacancies in the buffer layer 3, and the density of the buffer layer 3 is smaller than that of the electrolyte layer 4 and larger than that of the electrode layer 2. You can see that it is. From the image processing data of FIG. 5, it is estimated that the density of the buffer layer 3 is about 92%. Further, when the density of the buffer layer 3 obtained as described above was calculated from the result of measuring the X-ray reflectance, it was calculated to be 92%. That is, from the above results, it was confirmed that the density of the buffer layer 3 was larger than that of the electrode layer 2 and smaller than that of the electrolyte layer 4.

(Prototype 2: Example)
The firing temperature in the buffer layer forming step was changed to 1000 ° C., and the metal-supported electrochemical device E was obtained in the same steps as in Prototype 1. The thickness of the electrode layer 2 of the obtained sample was about 10 μm, the thickness of the buffer layer 3 was about 7 μm, and the thickness of the electrolyte layer 4 was about 4 μm.

The amount of He leak of the metal substrate 1 in the state of being laminated up to the buffer layer 3 was 7.5 mL / min · cm ² under a pressure of 0.2 MPa. The amount of He leak of the metal substrate 1 in the state of being laminated up to the electrolyte layer 4 was less than the detection limit of 1.0 mL / min · cm ² under a pressure of 0.2 MPa. Similar to Prototype 1, the amount of He leak in the state where the electrolyte layer 4 was laminated was significantly smaller than the amount of He leak in the state where the buffer layer up to 3 was laminated, which was below the detection limit. .. Therefore, it was confirmed that the formed electrolyte layer 4 is dense, has high gas barrier performance, and is of good quality.

Regarding the obtained metal-supported electrochemical element E, hydrogen gas was supplied to the electrode layer 2 and air was supplied to the counter electrode layer 6, and the open circuit voltage (OCV) of the solid oxide fuel cell was measured. The results were 1.09 V at 600 ° C, 1.08 V at 650 ° C, 1.05 V at 700 ° C, and 1.05 V at 750 ° C. The Measurement of the current value obtained, a current of 500mA / cm ² was obtained at 0.803V at 750 ° C., a current of 750mA / cm ² was obtained under the conditions of 0.700V.

An electron micrograph of a cross section of the metal-supported electrochemical device E thus obtained is shown in FIG. The electrode layer 2 has a large number of black voids and pores, and the density is relatively low. From the image processing data of FIG. 6, the density of the electrode layer 2 is estimated to be about 79%. Almost no black voids or vacancies are seen in the electrolyte layer 4, and the electrolyte layer 4 is very dense. From the image processing data of FIG. 6, it is estimated that the density of the electrolyte layer 4 is about 97% or more. On the other hand, since many small black spots are seen in the buffer layer 3, small voids and vacancies are present in the buffer layer 3, and the density of the buffer layer 3 is slightly reduced. From the image processing data of FIG. 6, it is estimated that the density of the buffer layer 3 is about 95%. That is, from the above results, it was confirmed that the density of the buffer layer 3 was larger than that of the electrode layer 2 and smaller than that of the electrolyte layer 4.

(Prototype 3: Example)
The firing temperature in the buffer layer forming step was changed to 950 ° C., and the metal-supported electrochemical device E was obtained in the same steps as in Prototype 1. The thickness of the electrode layer 2 of the obtained sample was about 13 μm, the thickness of the buffer layer 3 was about 7 μm, and the thickness of the electrolyte layer 4 was about 4 μm.

The amount of He leak of the metal substrate 1 in the state of being laminated up to the buffer layer 3 was 26.5 mL / min · cm ² under a pressure of 0.2 MPa. The amount of He leak of the metal substrate 1 in the state of being laminated up to the electrolyte layer 4 was less than the detection limit of 1.0 mL / min · cm ² under a pressure of 0.2 MPa. Similar to Prototype 1, the amount of He leak in the state where the electrolyte layer 4 was laminated was significantly smaller than the amount of He leak in the state where the buffer layer up to 3 was laminated, which was below the detection limit. .. Therefore, it was confirmed that the formed electrolyte layer 4 is dense, has high gas barrier performance, and is of good quality.

Regarding the obtained metal-supported electrochemical element E, hydrogen gas was supplied to the electrode layer 2 and air was supplied to the counter electrode layer 6, and the open circuit voltage (OCV) of the solid oxide fuel cell was measured. The result was 1.02 V at 750 ° C.

It can be used as an electrochemical device and a solid oxide fuel cell.

1: Metal substrate 1a: Through hole 1b: Metal oxide layer (diffusion suppression layer)
2: Electrode layer 3: Buffer layer 4: Electrolyte layer 5: Reaction prevention layer 6: Counter electrode electrode layer E: Metal-supported electrochemical element

Claims (14)

A metal substrate as a support having a plurality of through holes extending from the front side to the back side, an electrode layer formed on the metal substrate, a buffer layer formed on the electrode layer, and a buffer layer on the buffer layer. The electrode layer is porous, the electrolyte layer is dense, the density of the buffer layer is larger than the density of the electrode layer, and the electrolyte layer is formed in the above. rather smaller than the density of the,
A metal-supported electrochemical device having a buffer layer having a thickness of 10 μm or less . The metal-supported electrochemical device according to claim 1, wherein the buffer layer contains a ceria-based material. The metal-supported electrochemical device according to claim 1 or 2, wherein the electrolyte layer contains stabilized zirconia. The metal-supported electrochemical device according to any one of claims 1 to 3, wherein the thickness of the buffer layer is 4 μm or more. The metal-supported electrochemical device according to any one of claims 1 to 4 , wherein the density of the buffer layer is 50% or more and less than 98%. The metal-supported electrochemical device according to any one of claims 1 to 5 , wherein a dense electrolyte layer having a density of 98% or more is included in a part of the electrolyte layer. The metal-supported electrochemical element according to any one of claims 1 to 6 , further comprising a diffusion suppression layer that suppresses the diffusion of Cr from the metal substrate to the electrode layer. The metal-supported electrochemical device according to claim 7 , wherein the diffusion suppression layer is a metal oxide layer formed on the surface of the metal substrate. The metal-supported electrochemical device according to any one of claims 1 to 8, wherein the through hole is formed inside a region of the metal substrate on which the electrolyte layer is formed. The metal-supported electrochemical device according to any one of claims 1 to 9, wherein the through hole is formed inside a region of the metal substrate on which the electrode layer is formed. The metal-supported electrochemical element according to any one of claims 1 to 10 , which has a counter electrode layer formed on the electrolyte layer and serves as a counter electrode of the electrode layer. The metal-supported electrochemical device according to claim 11 , further comprising a reaction prevention layer formed between the electrolyte layer and the counter electrode layer. A solid oxide fuel cell having the metal-supported electrochemical element according to any one of claims 1 to 12 and capable of operating in a temperature range of 600 ° C. or higher and 750 ° C. or lower during rated operation. The method for manufacturing a metal-supported electrochemical element according to any one of claims 1 to 12 , wherein the electrode layer forming step of forming a porous electrode layer on a metal substrate as a support and the above-mentioned. It has a buffer layer forming step of forming a buffer layer on the electrode layer and an electrolyte layer forming step of forming a dense electrolyte layer on the buffer layer.
The density of the buffer layer is larger than that of the electrode layer and smaller than that of the electrolyte layer.
A method for manufacturing a metal-supported electrochemical element in which the electrode layer forming step, the buffer layer forming step, and the electrolyte layer forming step are performed at 1100 ° C. or lower.