JP2017022111A - Laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate appropriate for a solid oxide type electrochemical cell which reduces overvoltage in a fuel electrode layer or in a hydrogen electrode layer and improves a current-voltage property, an electrode support type half cell for solid oxide electrochemical cell which includes the laminate, reduces overvoltage in a fuel electrode layer or in a hydrogen electrode layer and improves a current-voltage property, an electrode support type unit cell for solid oxide type electrochemical cell and a solid electrolyte support type unit cell for solid oxide type electrochemical cell which include the laminate and improve performances.SOLUTION: The laminate comprises a fuel electrode layer or a hydrogen electrode layer and a solid electrolyte layer. The solid electrolyte layer contains an oxide ion conductive material as a main component, and the fuel electrode layer or the hydrogen electrode layer contains stabilized zirconia and nickel oxide. On a cross section of the fuel electrode layer or the hydrogen electrode layer, an average value for 10 sections of a total boundary length of the stabilized zirconia and the nickel oxide in a region for 3 μm from an interface with the solid electrolyte layer and within a section of a width of 10 μm is 25 μm or more and a standard deviation is 10 μm or less.SELECTED DRAWING: None

Description

  The present invention relates to a laminate suitable for a solid oxide electrochemical cell having a low overvoltage in a fuel electrode layer or a hydrogen electrode layer and excellent in current-voltage characteristics, and an overvoltage in a fuel electrode layer or a hydrogen electrode layer including the laminate. Electrode-supported half cell for solid oxide electrochemical cell having low current-voltage characteristics, and electrode-supported single cell and solid oxide electric cell for solid oxide electrochemical cell including the laminate and high performance The present invention relates to a solid electrolyte-supported single cell for chemical cells.

  In recent years, fuel cells have attracted attention as a clean energy source, and rapid improvement studies and practical application studies are being promoted for household power generation, commercial power generation, and automobile power generation. Among such fuel cells, a solid oxide fuel cell is expected as a power source for home use and business use because it has good power generation efficiency and excellent long-term stability.

  The solid electrolyte membrane of the solid oxide fuel cell conducts oxygen ions but does not pass electrons. Therefore, oxygen ions generated at the air electrode permeate the solid electrolyte membrane to reach the fuel electrode, and react with hydrogen to generate water and electrons to generate electricity. As a raw material for such a solid electrolyte membrane, zirconia stabilized with yttria or the like is mainly used, and the fuel electrode is composed of similar zirconia in addition to the conductive metal. As a result, a potential distribution that interferes with the reaction occurs at the interface between the stabilized zirconia and the conductive metal in the fuel electrode, and the three-phase interface between the stabilized zirconia, the conductive metal, and the gas phase, and the output voltage decreases. That is, overvoltage is observed. Such overvoltage is required to suppress the power generation performance of the solid oxide fuel cell.

  Patent Document 1 discloses a fuel cell single cell capable of improving output, in which the average value of the joining length of nickel particles and oxygen ion conductive material particles is defined in the cross section of the fuel electrode. It is disclosed.

JP 2014-26720 A

  As described above, there is known a fuel cell single cell in which the average value of the junction length between nickel particles and oxygen ion conductive material particles in the fuel electrode is defined in order to increase the output. However, there is a demand for a solid oxide fuel cell that has excellent current-voltage characteristics and further improved power generation performance, and a solid oxide electrolytic cell that consumes less power.

  Accordingly, the present invention provides a laminate suitable for a solid oxide electrochemical cell having a low overvoltage in the fuel electrode layer or the hydrogen electrode layer and excellent in current-voltage characteristics, and an overvoltage in the fuel electrode layer or the hydrogen electrode layer including the laminate. Electrode-supporting half cell for solid oxide electrochemical cell having low current and voltage characteristics, and electrode-supporting single cell and solid oxide form for solid oxide electrochemical cell including the laminate and high performance An object of the present invention is to provide a solid electrolyte supported single cell for an electrochemical cell.

  This inventor repeated earnest research in order to solve the said subject. As a result, in the fuel electrode layer or hydrogen electrode layer, the boundary length between stabilized zirconia particles and nickel oxide particles near the interface with the solid electrolyte layer is very important for the performance of the solid oxide electrochemical cell. And the present invention was completed.

  Hereinafter, the present invention will be described.

[1] A fuel electrode layer or a hydrogen electrode layer and a solid electrolyte layer,
The solid electrolyte layer contains an oxide ion conductive material as a main component,
The fuel or hydrogen electrode layer contains stabilized zirconia and nickel oxide,
In the cross section of the fuel electrode layer or the hydrogen electrode layer, the average value of the total boundary length of the stabilized zirconia and nickel oxide between 10 sections in the section from the interface with the solid electrolyte layer to 3 μm and in the section of 10 μm width Is a laminate having a standard deviation of 10 μm or less.

  [2] In the cross section of the fuel electrode layer or the hydrogen electrode layer, 10 sections having a boundary length of stabilized zirconia and nickel oxide in a section having a width of 10 μm and a region of 1 μm to 4 μm from the interface with the solid electrolyte layer The laminate according to the above [1], wherein the average value between them is 25 μm or more and the standard deviation is 10 μm or less.

[3] The laminate according to [1] or [2] above,
The fuel electrode layer or hydrogen electrode layer is composed of a fuel electrode support substrate or hydrogen electrode support substrate and a fuel electrode functional layer or hydrogen electrode functional layer,
An electrode-supporting half cell for a solid oxide electrochemical cell, wherein a fuel electrode functional layer or a hydrogen electrode functional layer is in contact with a solid electrolyte layer.

  [4] The electrode-supporting half cell for a solid oxide electrochemical cell according to the above [3], wherein a barrier layer is disposed on the surface of the solid electrolyte layer opposite to the fuel electrode functional layer or the hydrogen electrode functional layer. .

  [5] On the surface opposite to the fuel electrode functional layer or the hydrogen electrode functional layer of the solid electrolyte layer of the electrode-supporting half cell for a solid oxide electrochemical cell according to [3] above, or [4] above A solid oxide characterized in that an air electrode layer or an oxygen electrode layer is formed on the surface opposite to the solid electrolyte layer of the barrier layer of the electrode-supported half cell for solid oxide electrochemical cells described in 1. Electrode-supported single cell for physical electrochemical cells.

[6] The laminate according to [1] or [2] above is included,
The solid electrolyte layer comprises a solid electrolyte support substrate;
A solid electrolyte supported single cell for a solid oxide electrochemical cell, comprising a fuel electrode layer or a hydrogen electrode layer, a solid electrolyte support substrate, and an air electrode layer or an oxygen electrode layer in this order.

  [7] The solid electrolyte supporting single cell for a solid oxide electrochemical cell according to [6], further including a barrier layer between the solid electrolyte supporting substrate and the air electrode layer or the oxygen electrode layer.

  In the unit cell for a solid oxide electrochemical cell according to the present invention, the overvoltage of the fuel electrode layer or the hydrogen electrode layer is reduced, and the current-voltage characteristics are excellent. Therefore, the solid oxide fuel cell unit cell according to the present invention has high output, and the solid oxide electrolytic cell according to the present invention has low power consumption and high efficiency.

  The laminate according to the present invention has a fuel electrode layer or a hydrogen electrode layer and a solid electrolyte layer. The fuel electrode layer of the laminate is composed of a fuel electrode support substrate and a fuel electrode functional layer, and is stacked in the order of the fuel electrode support substrate, the fuel electrode functional layer, and the solid electrolyte layer to support the fuel electrode for a solid oxide fuel cell. A solid electrolyte support substrate, and a solid electrolyte support single cell for a solid oxide fuel cell in which a fuel electrode layer and an air electrode layer are arranged on each surface of the solid electrolyte support substrate. Good. An air electrode layer may be disposed on the solid electrolyte layer of the solid electrode type half cell for a solid oxide fuel cell to form a single electrode cell for a solid oxide fuel cell. Further, the hydrogen electrode layer of the laminate is composed of a hydrogen electrode support substrate and a hydrogen electrode functional layer, and is stacked in the order of the hydrogen electrode support substrate, the hydrogen electrode functional layer, and the solid electrolyte layer to form hydrogen for a solid oxide electrolytic cell. It may be an electrode-supported half cell, or a solid electrolyte support single cell for a solid oxide electrolytic cell in which the solid electrolyte layer is a solid electrolyte support substrate, and a hydrogen electrode layer and an oxygen electrode layer are arranged on each surface of the solid electrolyte support substrate. It is good. An oxygen electrode layer may be disposed on the solid electrolyte layer of the hydrogen electrode supporting half cell for the solid oxide electrolytic cell to form a hydrogen electrode supporting single cell for the solid oxide electrolytic cell.

  In the present invention, the “solid oxide electrochemical cell” includes a solid oxide fuel cell (SOFC) and a solid oxide electrolytic cell (SOEC). Although depending on the components constituting the electrolyte layer, for example, SOFC fuel electrode generates water and electrons from hydrogen and oxide ions, and air electrode generates oxide ions from oxygen and electrons. In the SOFC, electrons flow from the fuel electrode to the external circuit, so the fuel electrode corresponds to the anode, and the air electrode corresponds to the cathode, because electrons flow from the external circuit. On the other hand, in SOEC, the hydrogen electrode corresponds to a cathode because oxide ions and hydrogen are generated from water and electrons, and the oxygen electrode corresponds to an anode because oxygen and electrons are generated from oxide ions. Since SOFC can also be used as SOEC, the following mainly describes SOFC representatively. The SOFC fuel electrode corresponds to the SOEC hydrogen electrode, and the SOFC air electrode corresponds to the SOEC oxygen electrode. The electrode-supporting single cell is preferably a fuel-electrode-supporting single cell, and the fuel-electrode-supporting single cell will be representatively described below.

  FUEL ELECTRODE LAYER OF LAMINATE OF THE INVENTION, i.e. SOFC Fuel Electrode Support Half Cell, SOFC Fuel Electrode Support Single Cell Fuel Electrode Support Substrate and Fuel Electrode Functional Layer, and SOFC Solid Electrolyte Support Single Cell The fuel electrode layer is generally a porous body containing stabilized zirconia and nickel oxide. Hereinafter, the fuel electrode support substrate, the fuel electrode functional layer, and the fuel electrode layer may be collectively referred to as “fuel electrode”.

  The stabilized zirconia constituting the fuel electrode is zirconia whose crystal structure is stabilized by solid solution of yttria, scandia, ytterbia, etc., and at least one selected from the group consisting of yttria, scandia, and ytterbia Solid solution stabilized zirconia is preferred. The proportion of yttria, scandia and / or ytterbia in the stabilized zirconia, that is, the solid solution amount thereof is preferably 2 mol% or more and 15 mol% or less. When the proportion is 2 mol% or more, effects such as a crystal phase stabilization effect can be obtained more reliably. On the other hand, if the solid solution amount of yttria, scandia, and ytterbia is excessive, the strength may be lowered. Therefore, the proportion is preferably 15 mol% or less. As the said ratio, 3 mol% or more and 12 mol% or less are more preferable. Among yttria, scandia, and ytterbia, yttria and ytterbia are preferable, and ytterbia is particularly preferable.

The stabilized zirconia constituting the fuel electrode according to the present invention may further contain other metal oxides in addition to yttria, scandia, and ytterbia. The addition of a metal oxide may further improve the properties of the zirconia sheet such as oxygen ion conductivity, strength, and durability. Examples of such metal oxides include alkaline earth metal oxides such as MgO, CaO, SrO, BaO; Ce ₂ O ₃ , La ₂ O ₃ , Pr ₂ O ₃ , Nd ₂ O ₃ , Sm ₂ O ₃ , Rare earth element oxides such as Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₂ O ₃ , Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ ; Group 13 such as Al ₂ O ₃ , In ₂ O ₃ Element oxides; Group 14 element oxides such as SiO ₂ , Ge ₂ O ₃ and SnO ₂ ; Group 15 element oxides such as Bi ₂ O ₃ and Sb ₂ O ₃ ; Group 4 element oxidations such as TiO ₂ A Group 5 element oxide such as Nb ₂ O ₅ and Ta ₂ O ₅ . Among these, lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), gadolinium (Gd), terbium (Tb), aluminum (Al), and titanium (Ti) are selected. One or more metal oxides are particularly preferred. Any one of these other metal oxides may be used, or a combination of two or more thereof may be used. The ratio of the other metal oxide to the whole zirconia is 0.5 mol% or more and 2.5 or more. Mole% or less is preferable.

  The ratio of stabilized zirconia and nickel oxide in the fuel electrode may be adjusted as appropriate. For example, the mass ratio of nickel oxide to the total of stabilized zirconia and nickel oxide may be about 40% by mass to 80% by mass. .

  The fuel electrode support substrate has a role of supplying fuel gas such as hydrogen to the fuel electrode functional layer so as not to be nonuniform, delivering electrons generated by the reaction to the interconnector, and supporting the electrolyte layer and the air electrode layer. The fuel electrode functional layer is a layer in which an electrochemical reaction is mainly performed. The fuel electrode layer of the solid electrolyte supporting single cell for SOFC is also a layer in which electrochemical reaction is mainly performed. The fuel electrode layer may be provided with a current collector for uniformly supplying the fuel gas to the fuel electrode layer and transferring electrons generated by the reaction to the interconnector.

  The reaction at the fuel electrode occurs in three phases: stabilized zirconia that supplies oxygen ions, a gas phase that supplies fuel gas, and metallic nickel that receives electrons. Therefore, although the fuel electrode is porous, the porosity of the fuel electrode support substrate is preferably higher than that of the fuel electrode functional layer. Regarding the thickness, generally, the thickness of the fuel electrode functional layer can be about 5 μm to 30 μm, and the thickness of the fuel electrode support substrate can be about 100 μm to 10000 μm. In the case of a solid electrolyte supporting single cell for SOFC, the thickness of the fuel electrode layer can be about 1 μm or more and 50 μm or less.

  The composition of the fuel electrode support substrate and the fuel electrode functional layer may be the same or different. For example, only the composition and ratio of the stabilized zirconia yttria, scandia, and ytterbia may be changed.

  The solid electrolyte layer of the SOFC fuel electrode support half cell and the SOFC fuel electrode support single cell and the solid electrolyte support substrate of the SOFC solid electrolyte support single cell include an oxide ion conductive material as a main component, and an oxide. Shows ionic conductivity. The electron conductivity is preferably small. For example, at the operating temperature, the transport number of oxide ions is preferably 0.90 or more, and more preferably 0.95 or more.

  In the present invention, the solid electrolyte layer “contains an oxide ion conductive material as a main component” means that the main component of the solid electrolyte layer is an oxide ion conductive material, and the solid electrolyte layer is an oxide ion as described above. Although it will not restrict | limit especially if it shows electroconductivity, For example, it means that 90 mass% or more of a solid electrolyte layer is an oxide ion conductive material. As the said ratio, 91 mass% or more is preferable, 92 mass% or more or 93 mass% or more is more preferable, 94 mass% or more or 95 mass% or more is still more preferable.

  In addition, inevitable impurities derived from raw materials may be mixed in the solid electrolyte layer, or inevitable impurities may be attached or mixed in the manufacturing process. In addition, if the sinterability of the solid electrolyte layer is poor, gas cross-leakage is likely to occur, and in this case, some fuel gas and oxidant gas are not used in the electrochemical reaction and directly combusted, resulting in efficiency. Therefore, the solid electrolyte layer is required to have high denseness that does not transmit gas. For this reason, as a means for improving the sinterability of the solid electrolyte layer and increasing the denseness, if the oxide ion conductivity is not impaired, in addition to the oxide ion conductive material, Additives may be included. Therefore, it is preferable that the solid electrolyte layer is substantially made of only an oxide ion conductive material except that it contains inevitable impurities and additives such as a sintering aid.

  As the oxide ion conductive material, preferably, the same materials as those exemplified as the stabilized zirconia constituting the fuel electrode can be used. That is, the stabilized zirconia constituting the solid electrolyte is preferably stabilized zirconia in which at least one selected from the group consisting of yttria, scandia, and ytterbia is dissolved. The proportion of yttria, scandia and / or ytterbia in the stabilized zirconia, that is, the solid solution amount thereof is preferably 2 mol% or more and 15 mol% or less. When the proportion is 2 mol% or more, effects such as a crystal phase stabilization effect can be obtained more reliably. On the other hand, if the solid solution amount of yttria, scandia, and ytterbia is excessive, the strength may be lowered. Therefore, the proportion is preferably 15 mol% or less. As the said ratio, 3 mol% or more and 12 mol% or less are more preferable. Among yttria, scandia, and ytterbia, yttria and ytterbia are preferable, and ytterbia is particularly preferable. In the laminate according to the present invention, the stabilized zirconia constituting the solid electrolyte and the stabilized zirconia constituting the fuel electrode may be the same or different.

  The thickness of the solid electrolyte layer in the SOFC fuel electrode supporting half cell and the SOFC fuel electrode supporting single cell according to the present invention can be, for example, about 1 μm to 50 μm. The thinner the thickness, the higher the power generation performance of the solid oxide fuel cell. If the thickness is 50 μm or less, sufficiently high power generation characteristics can be obtained. On the other hand, if it is too thin, there is a possibility that problems such as a short circuit may occur. Therefore, the thickness is preferably 1 μm or more. The thickness is more preferably 1.5 μm or more, further preferably 2 μm or more, more preferably 30 μm or less, still more preferably 20 μm or less, and particularly preferably 15 μm or less.

  The thickness of the solid electrolyte support substrate in the solid electrolyte support type single cell for SOFC according to the present invention can be, for example, about 80 μm or more and 2000 μm or less. If it is 2000 μm or less, sufficiently high power generation characteristics can be obtained. On the other hand, if the thickness is too thin, there may be a problem in strength and the like. Therefore, the thickness is preferably 80 μm or more.

  On the solid electrolyte layer of the SOFC fuel electrode support type half cell according to the present invention, between the solid electrolyte layer and the air electrode layer of the SOFC fuel electrode support type single cell, and the solid state of the SOFC solid electrolyte support type single cell A barrier layer may be disposed between the electrolyte support substrate and the air electrode layer in order to suppress the reaction between the solid electrolyte and the air electrode layer.

Examples of the component of the barrier layer include ceria doped with one or more metals selected from the group consisting of Y, Sm, Gd, Nd, Pr, Sc, and Ga, and more specifically, Ce _{1. -z} M _z O _2-w (wherein M represents one or more metals selected from the group consisting of Y, Sm, Gd, Nd, Pr, Sc, and Ga; 0.05 ≦ z ≦ 0.4; 0 ≦ w <0.5).

  The thickness of the barrier layer can be about 1 μm or more and 20 μm or less.

As the material for the air electrode layer, a material made of a perovskite oxide that is excellent in electronic conductivity and stable even in an oxidizing atmosphere is generally used. Specifically, lanthanum manganite in which a part of lanthanum is substituted with strontium, such as La _0.8 Sr _0.2 MnO ₃ , La _0.6 Sr _0.4 CoO ₃ , La _0.6 Sr _0.4 FeO ₃ , La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O _3, etc. Lanthanum ferrite, lanthanum cobaltite and the like are preferable as the air electrode layer material. In addition, in order to impart oxygen ion conductivity to the air electrode layer, ceria doped with rare earth or the like can be appropriately mixed.

  The thickness of the air electrode layer can be about 5 μm or more and 50 μm or less.

  The shape and size of the SOFC fuel electrode supporting half cell, the SOFC fuel electrode supporting single cell, and the SOFC solid electrolyte supporting single cell according to the present invention may be appropriately selected. For example, the shape is not particularly limited, such as a square such as a square or a rectangle, or a circle. The length of one side of the square or the diameter of the circle can be, for example, 30 mm or more and 300 mm or less. The length and diameter are more preferably 50 mm or more, further preferably 70 mm or more, more preferably 200 mm or less, and further preferably 150 mm or less.

  The cross section of the fuel electrode layer of the laminate according to the present invention, that is, the cross section of the fuel electrode functional layer of the SOFC fuel electrode supporting half cell and the SOFC fuel electrode supporting single cell according to the present invention, and the SOFC solid electrolyte support In the cross section of the fuel electrode layer of the type single cell, the total boundary length of the stabilized zirconia and nickel oxide in the region of 3 μm from the interface with the solid electrolyte layer or the solid electrolyte support substrate and within the 10 μm wide section, respectively. The average value between 10 sections is 25 μm or more and the standard deviation is 10 μm or less. According to the inventor's knowledge, the state of the interface between the solid electrolyte and the fuel electrode is the most important for the efficiency of the reaction at the fuel electrode, and between the stabilized zirconia particles and the nickel oxide particles in the vicinity of the interface. If the boundary length is used as an index, the power generation performance of the cell can be evaluated.

  Nickel oxide is reduced to a metallic nickel in a reducing atmosphere. Therefore, in the present invention, the total boundary length is measured before the reduction including the power generation. Further, even after power generation or reduction once, measurement may be performed after treatment in an oxidizing atmosphere.

  The total boundary length is measured at the cross section of the fuel electrode functional layer or the fuel electrode layer. Therefore, the total boundary length is measured by cutting the SOFC fuel electrode supporting half cell, the SOFC fuel electrode supporting single cell, or the SOFC solid electrolyte supporting single cell in the longitudinal direction. The cutting position is not particularly limited. For example, the cutting position may be cut in the vertical direction of the plane along the center of the cell, that is, the center of the circle in the case of a circular cell and the line including the intersection of diagonal lines in the case of a square cell.

  In the present invention, the total boundary length is measured by observing a cross section of the fuel electrode functional layer or the fuel electrode layer with a scanning electron microscope (SEM). What is necessary is just to adjust an expansion magnification suitably, and should just be set as the magnification which said 3 micrometer x 10 micrometer area | region is fully contained in one visual field. Specifically, for example, the magnification can be about 3,000 times or more and 15,000 times or less, but it is only necessary to identify stabilized zirconia, nickel oxide, and pores in a 3 μm × 10 μm section in the image. The preferred magnification may vary depending on the size of the medium such as a display, and is not particularly limited as long as it is clear enough to identify the above three.

  Within the enlarged field of view by SEM, the stabilized zirconia, nickel oxide and vacancies are distinguished. These three can be distinguished by using secondary electron images acquired by SEM and energy dispersive X-ray analysis or wavelength dispersive X-ray analysis in combination, but in order to distinguish easily and clearly in a short time It is preferable to obtain a reflected electron image. With the SEM-reflected electron image, the distinction between the stabilized zirconia particles and the nickel oxide particles in the fuel electrode is clearer, and the boundary length between both particles can be measured more accurately. Stabilized zirconia, nickel oxide, and pores may be distinguished by color density by analyzing the image with image analysis software. However, the judgment may be wrong depending on the accuracy of the image analysis software. Are preferably distinguished visually.

  The interface between the fuel electrode functional layer and the solid electrolyte layer and the interface between the fuel electrode layer and the solid electrolyte support substrate are usually porous. The fuel electrode functional layer and the fuel electrode layer are usually porous. The determination may be difficult because the solid electrolyte material enters the pores in the surface of the layer. Therefore, in the present invention, the interface is determined by the following procedure.

-Identify the nickel oxide particles closest to the solid electrolyte in the enlarged field of view by SEM.-In the same enlarged field of view, select the nickel oxide particles closest to the solid electrolyte in the region 2 μm or more away from the end of the nickel oxide particles. Identify ・ The straight line connecting the end portions of the two nickel oxide particles on the solid electrolyte side is the interface between the fuel electrode and the solid electrolyte. In the present invention, the area is 3 μm from the interface and has a width of 10 μm. Within the compartment, the boundary between the stabilized zirconia particles and the nickel oxide particles is specified, and the total length is obtained. The total length can be obtained using image analysis software.

  In the present invention, the total boundary length between the stabilized zirconia particles and the nickel oxide particles is determined in each of 10 sections of 3 μm × 10 μm in the cross section of the fuel electrode functional layer or the fuel electrode layer. The ten sections are preferably set so that the areas do not overlap each other. Since it is unlikely that the planar length of the fuel electrode functional layer or the fuel electrode layer is less than 100 μm, it is easy to set 10 sections so that each region does not overlap. Moreover, it is preferable that the 10 sections are set evenly in the planar direction of the fuel electrode functional layer and the fuel electrode layer. For example, a section separated by 5 μm or more and 50 μm or less from the end of the measurement electrode cross section of the fuel electrode functional layer or the fuel electrode layer is set, and the remaining 8 sections are set with equal distances at both end sections. It is possible to set a section including the central portion in addition to the section section, and set the remaining seven sections with a distance as uniform as possible among the set three sections.

  The average value of the total boundary length between the 10 sections can be calculated by adding up the total boundary length between the 10 sections and dividing by 10.

  In the present invention, the average value of the total boundary length between the 10 sections is 25 μm or more. Since the reaction at the fuel electrode proceeds more efficiently as the value is larger, the value is preferably 50 μm or more, more preferably 60 μm or more, further preferably 70 μm or more, and even more preferably 80 μm or more. On the other hand, if the value is too large, the supply of the fuel gas and the discharge of the generated gas are delayed with respect to the reaction, and the supply and discharge of the gas regulates the power generation efficiency, which may reduce the power generation efficiency. Therefore, the value is preferably 300 μm or less, and more preferably 200 μm or less.

  Moreover, in this invention, the standard deviation of the total boundary length between said 10 divisions is 10 micrometers or less. Even when the average value of the total boundary length is sufficiently large, if the value of the standard deviation is large, the reaction efficiency may be biased in the surface direction of the fuel electrode, and a high output cell may not be obtained. is there. In some cases, the reaction may be biased and the fuel electrode may be deactivated quickly. Therefore, the value of the standard deviation is preferably 9.9 μm or less, more preferably 9.8 μm or less, and further preferably 9.6 μm or less. The standard deviation value is preferably as small as possible from the viewpoint of the uniformity of the reaction at the fuel electrode, but if it is too small, it may take excessive effort to adjust the particle size distribution of the raw material particles. Is preferably 1.0 μm or more, more preferably 2.0 μm or more, and even more preferably 3.0 μm or more.

  Further, in the cross section of the fuel electrode functional layer of the SOFC fuel electrode supporting half cell and the SOFC fuel electrode supporting single cell according to the present invention, and in the cross section of the fuel electrode layer of the SOFC solid electrolyte supporting single cell, solid The average value between 10 sections of the total boundary length of stabilized zirconia and nickel oxide in the area of 1 μm or more and 4 μm or less from the interface with the electrolyte layer or the solid electrolyte support substrate and the width of 10 μm is 25 μm or more. The standard deviation is preferably 10 μm or less. As described above, according to the knowledge of the present inventor, the state of the interface between the solid electrolyte and the fuel electrode is the most important for increasing the efficiency of the reaction at the fuel electrode. It can affect the efficiency of the reaction at the pole.

  The total boundary length in the region can also be measured in the same manner as the boundary length in the vicinity of the interface.

  Next, a method for manufacturing the SOFC fuel electrode support half cell, the SOFC fuel electrode support single cell, and the SOFC solid electrolyte support single cell according to the present invention will be described.

1. Slurry preparation step In this step, a slurry is obtained by mixing the raw material powder, solvent and binder constituting each layer. In addition, for example, a plasticizer, a dispersant, an antifoaming agent, and the like may be added to the slurry. In the case of a slurry for a fuel electrode, nickel oxide powder may also be used, and a pore forming material or a foaming agent for making it porous may be added.

  As a solvent used for slurry preparation, for example, alcohols such as methanol, ethanol, 2-propanol, 1-butanol, 1-hexanol and α-terpineol; ketones such as acetone and 2-butanone; pentane, hexane, heptane and the like Aliphatic hydrocarbons; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; and acetic acid esters such as methyl acetate, ethyl acetate, and butyl acetate. To do. These solvents can be used alone or in combination of two or more.

  As a solvent for preparing the slurry for the fuel electrode functional layer, ethanol or isopropanol is particularly preferable, and isopropanol is more preferable. Water is less toxic, but when water is used, the pulverized particles tend to aggregate. In addition, methanol and toluene are relatively toxic. Ethanol and isopropanol are relatively low in toxicity, and fine particles are less likely to aggregate than water, and isopropanol is cheaper.

  The amount of solvent used should be adjusted in consideration of the viscosity of the slurry during green sheet molding, preferably the slurry viscosity is 1 Pa · s to 80 Pa · s, more preferably 1 Pa · s to 50 Pa · s. It is better to adjust the range.

  The type of binder used when producing the slurry is not particularly limited as long as it is decomposed by firing or removed by burning, and a conventionally known organic binder is appropriately selected and used. be able to. Examples of the organic binder include an ethylene copolymer, a styrene copolymer, a (meth) acrylate copolymer, a vinyl acetate copolymer, a maleic acid copolymer, a polyvinyl butyral resin, a vinyl acetal resin, Examples thereof include vinyl formal resins, vinyl alcohol resins, waxes, and celluloses such as ethyl cellulose.

  Among these, a (meth) acrylate copolymer having a number average molecular weight of 5,000 to 200,000, more preferably 10,000 to 50,000 is particularly preferable. These organic binders can be used alone or in combination of two or more as necessary. Particularly preferable is a polymer of a monomer containing 60% by mass or more of n-butyl methacrylate, isobutyl methacrylate and / or 2-ethylhexyl acrylate.

  The plasticizer used in the present invention is preferably added to impart flexibility to the green sheet. Examples of the plasticizer include a low molecular plasticizer, a co-oligomer plasticizer, and a high molecular plasticizer. Examples of the low molecular plasticizer include phthalic acid esters such as dibutyl phthalate and dioctyl phthalate. Examples of the co-oligomer plasticizer and the polymer plasticizer include polyesters.

  In preparing the slurry, a dispersant may be added to promote peptization and dispersion of the solid electrolyte material, increase the fluidity of the slurry, and suppress sedimentation of the solid electrolyte material in the slurry.

  What is necessary is just to mix said each component by a conventional method. For example, when a raw material powder having a desired secondary particle size is obtained in advance, it may be mixed using a disper or the like under a condition that is not further pulverized. When the secondary particle diameter of the raw material powder is not adjusted in advance, it may be pulverized and mixed until a desired secondary particle diameter is obtained using a ball mill or the like.

  Particularly in the present invention, the average value and the standard deviation of the total boundary length of the stabilized zirconia particles and the nickel oxide particles in a predetermined section of the cross section of the fuel electrode are adjusted to a predetermined range. Therefore, it is preferable that the stabilized zirconia particles and the nickel oxide particles are pulverized, pulverized, and mixed by a ball mill or the like so as to be as uniform and fine as possible before slurrying or when slurrying together with other components. . More specifically, since fine particles usually have a large surface area, they aggregate by van der Waals force to form secondary particles and tertiary particles. Such higher-order particles are pulverized to primary particles, and stabilized zirconia particles and nickel oxide particles are sufficiently mixed.

  There are two types of ball mills: dry and wet, but each has advantages, so it can be selected or combined as appropriate. For example, wet pulverization has no dust problem and has an advantage that the pulverization speed is higher than that of dry pulverization and is suitable for fine pulverization. On the other hand, dry crushing can directly transmit the impact of the ball to the powder without using a solvent, so that it is desirable to avoid crushing the powder containing coarse particles and mixing impurities due to wear of the ball, etc. Suitable for complexing particles.

  In the present invention, in addition to the above-described preliminary pulverization, fine particles dispersed in a state close to primary particles may be mixed well and used, or fine particles from which aggregated particles have been removed in advance by a sieve or the like are mixed well. However, preliminary grinding with a ball mill or the like is considered to be the most efficient.

  In the fuel electrode functional layer and the fuel electrode layer, the size of aggregated particles in the raw material paste is also important. For example, if coarse raw material particles are present in the paste, coarse stabilized zirconia crystal particles and nickel oxide particles are formed in the fuel electrode functional layer and fuel electrode layer after firing, and the boundary length between the two particles is shortened. Because it ends up.

  The pulverization conditions for the stabilized zirconia and nickel oxide raw material particles may be determined while measuring the presence or absence of aggregated particles contained in the particles contained in the paste. For example, the particle size distribution of the particles contained in the paste can be measured with a particle size distribution meter, and can be determined from the average particle size or the maximum particle size that can be grasped from the particle size distribution. The maximum particle size can be measured with a grindometer. In addition, it is possible to measure the size and configuration of the aggregated particles by observing the paste with an SEM or the like, but the particle size distribution measurement or the measurement by a grindometer is more efficient.

  In addition to adjusting the pulverization conditions as described above, the aggregated particles in the paste can be crushed by optimizing the type and amount of the solvent and dispersant to be blended in the paste.

  The degree of pulverization may be adjusted as appropriate. For example, the average secondary particle diameter of the raw material powder in the paste may be about 0.1 μm to 5.0 μm. Moreover, it is preferable that the maximum particle diameter of the raw material powder contained in the paste is 12 μm or less.

2. Manufacturing process of supporting substrate Next, the fuel electrode supporting substrate green sheet or the solid electrolyte supporting substrate green sheet is obtained by applying the slurry to the substrate and then drying.

  As the substrate, a substrate film such as a PET film can be used.

  The method for applying the slurry is not particularly limited, and conventional methods such as a doctor blade method, a calender roll method, and a printing method can be used. Specifically, the slurry is transported to a coating dam, cast on a base material with a doctor blade or a screen printing machine so as to have a uniform thickness, and dried to obtain a green sheet.

  What is necessary is just to adjust coating thickness suitably according to the thickness of the target fuel electrode support substrate or solid electrolyte support substrate. Further, the shape and size of the green sheet may be determined in accordance with the shape and size of the target fuel electrode support substrate and solid electrolyte support substrate. For example, what is necessary is just to match | combine with the base material to be used. In the case of manufacturing a solid electrolyte support substrate or a fuel electrode support substrate, it may be cut into a desired shape or size after having a long width of about 10 cm to 400 cm.

  The drying conditions of the coating slurry may be appropriately adjusted according to the type of solvent used, but are usually 40 ° C. or higher, more preferably 80 ° C. or higher and about 150 ° C. or lower. Drying may be performed at a constant temperature, or may be performed by heating by successively raising the temperature sequentially such as 50 ° C., 80 ° C., and 120 ° C.

3. Lamination process By this process, the green layer of each layer is formed on the said green sheet or a support substrate on the conditions similar to the said process 2 by coating and drying of the raw material paste of each layer.

  In addition, after the said process 2, the execution order of this process and the sintering process which is the following process is arbitrary, and after forming each two or more layers as a green layer, it may co-sinter together, or green Layer formation and sintering may be repeated one by one. For example, a fuel electrode functional layer green layer may be formed by this step on the fuel electrode support substrate green sheet obtained by the above step 2, or the fuel electrode support substrate green sheet obtained by the above step 2 may be formed. After sintering in the next step 4 to form a fuel electrode support substrate, a fuel electrode functional layer green layer may be formed thereon by this step.

4). Sintering step In this step, the green sheet or green layer is sintered.

  The sintering conditions may be appropriately adjusted. For example, the sintering is performed at 1200 ° C. or more and 1500 ° C. or less. If it sinters at 1200 degreeC or more, sufficient baking effect will be acquired and sufficient intensity | strength will be acquired as a support substrate or each layer. On the other hand, if the sintering temperature is too high, the crystal grain size of the sheet becomes excessive and the toughness may be reduced, so the upper limit is set to 1500 ° C. More preferably, it is 1250 degreeC or more and 1450 degrees C or less.

  The heating rate up to the sintering temperature may be adjusted as appropriate, but can usually be about 0.05 ° C./min to 4 ° C./min.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

  As described above, the SOFC can also be used as an SOEC. The fuel electrode supported SOFC manufactured below can also be used as a hydrogen electrode supported SOEC. Whether it is SOFC or SOEC is merely a mode of use and is not particularly limited.

Example 1
(1) Production of fuel electrode support substrate green sheet 60 parts by mass of nickel oxide (Nikko Rica “High-Purity Nickel Oxide F”) as a conductive component and 3 mol% yttria stabilized zirconia powder (“TZ3Y” manufactured by Tosoh Corporation) as a skeletal component ”) 40 parts by mass, 10 parts by mass of carbon black (“ SGP-3 ”manufactured by SEC Carbon Co., Ltd.) as a pore-forming agent, a binder made of a methacrylate copolymer (molecular weight: 30,000; glass transition temperature: −8 ° C.) , Solid content concentration: 50 parts by mass) 30 parts by mass, 2 parts by mass of dibutyl phthalate as a plasticizer, and 80 parts by mass of a mixed solvent of toluene / isopropyl alcohol = 3/2 (mass ratio) as a dispersion medium were mixed by a ball mill. A slurry was prepared. Using the obtained slurry, a sheet was formed by a doctor blade method and dried at 70 ° C. for 5 hours to prepare a fuel electrode supporting substrate green sheet having a thickness of 300 μm.

(2) Ball mill treatment of powder for fuel electrode functional layer In a plastic container, 60 parts by mass of nickel oxide (“high purity nickel oxide F” manufactured by Nikko Rica Co., Ltd.) as a conductive component and 8 mol% yttria stabilized zirconia powder as an ion conductive component (Tosoh Corporation “TZ8Y”) 40 parts by mass, ethanol was added as a dispersion medium, and pulverized and mixed by a ball mill, followed by drying to obtain a ball milled NiO / 8YSZ mixed powder.

  The average particle diameter (D50) of the sample powder was measured under the following conditions. Sodium pyrophosphate decahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in water to obtain a 0.2% by weight aqueous solution of sodium pyrophosphate, which was used as a dispersion medium. The sample powder was dispersed in this dispersion medium, and the particle size of the powder was measured using a laser diffraction / scattering particle size distribution measuring apparatus (“Model number LA-920” manufactured by Horiba, Ltd.). In the above ball mill treatment, a powder having an average particle size of 0.21 μm was obtained by adjusting the rotation time.

(3) Formation of Green Layer for Fuel Electrode Functional Layer 60 parts by mass of ball mill-treated NiO / 8YSZ mixed powder obtained in (2) above, 36 parts by mass of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent, and ethyl cellulose as a binder 4 parts by mass (manufactured by Wako Pure Chemical Industries, Ltd.), 6 parts by mass of dibutyl phthalate (manufactured by Wako Pure Chemical Industries, Ltd.) as a plasticizer, and 4 parts by mass of a sorbitan fatty acid ester surfactant as a dispersant are mixed using a mortar. After that, the mixture was crushed using a three-roll mill (EXAKT Technologies, “Model M-80S”, roll material: alumina) to prepare a fuel electrode functional layer paste.

  The obtained paste was dispersed in ethanol, and the particle size of solids contained in the paste was measured using a laser diffraction / scattering particle size distribution analyzer (“Model number LA-920” manufactured by Horiba, Ltd.). The particle size was 0.23 μm and the maximum particle size was 5.3 μm.

  The fuel electrode functional layer paste is printed on the fuel electrode support substrate green sheet obtained in (1) above so that the thickness after firing is 20 μm by screen printing, and dried at 100 ° C. for 30 minutes, A green layer for a fuel electrode functional layer was formed.

(4) Formation of Green Layer for Electrolyte Layer 60 parts by mass of 8 mol% yttria-stabilized zirconia powder (“TZ8Y” manufactured by Tosoh Corporation), 5 parts by mass of ethyl cellulose (manufactured by Wako Pure Chemical Industries) as a binder, and α-terpineol as a solvent 40 parts by weight (manufactured by Wako Pure Chemical Industries, Ltd.), 6 parts by mass of dibutyl phthalate (manufactured by Wako Pure Chemical Industries, Ltd.) as a plasticizer, and a sorbitan acid ester surfactant (“Ionet S-manufactured by Sanyo Kasei Kogyo Co., Ltd.) as a dispersant. 80 ") 5 parts by mass were mixed using a mortar, and then pulverized using a three-roll mill (" EX-80 Technologies "" M-80S ", roll material: alumina) to prepare an 8YSZ electrolyte layer paste. . In this pasting treatment, pulverization and kneading were carried out by adjusting the gap between the three roll mills and the rotation speed until the particle size measured with a grindometer was 10 μm or less. The size of the particle size using a grindometer was measured according to the maximum particle size of the aggregate JIS K5400 (1900) 4.7.2 filament method. Specifically, the paste was dropped in a groove of a grindometer (BYK), and a paste layer having a continuously varying thickness was formed in the ironing groove using a scraper. Under the present circumstances, the thickness of the layer of the location where the filament by the aggregate in a paste began to appear three or more was read, and it was set as the maximum particle diameter of the aggregate. The measurement was performed 3 times, and the average value of 3 times was obtained.

  On the green layer for a fuel electrode functional layer obtained in (3) above, the 8YSZ electrolyte layer paste is printed by screen printing so that the thickness after firing is 5 μm, and dried at 100 ° C. for 30 minutes, A green layer for an electrolyte layer was formed.

(5) Formation of Green Layer for Barrier Layer 60 parts by mass of ceria powder (manufactured by Anan Kasei Co., Ltd.) doped with 10 mol% gadolinia as a ceramic material, 5 parts by mass of ethyl cellulose (manufactured by Wako Pure Chemical Industries, Ltd.) as a binder, solvent Α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) 40 parts by mass, dibutyl phthalate (manufactured by Wako Pure Chemical Industries, Ltd.) 6 parts by mass as a plasticizer, and sorbitan acid ester surfactant (manufactured by Sanyo Chemical Industries, Ltd.) as a dispersant. By mixing 5 parts by mass of “Ionette S-80” using a mortar, and then crushing using 3 roll mills (“EX-80 Technologies” “Model M-80S”, roll material: alumina), the barrier A layer paste was obtained. In this pasting treatment, the mixture was pulverized and kneaded until the particle size measured with a grindometer was 10 μm or less by adjusting the gap between the three roll mills and the rotational speed.

  The barrier layer paste was printed on the green layer of the electrolyte layer obtained in (4) so as to have a thickness of 3 μm or less by screen printing. This was dried at 100 ° C. for 30 minutes to form a barrier layer green layer.

(6) Firing The fuel electrode supporting substrate green sheet on which the green layer for the fuel electrode functional layer, the green layer for the electrolyte layer, and the green layer for the barrier layer obtained in the above (5) is formed has a side of 60 mm after firing. Perforated to be a square. After punching, 20 sheets of a fuel electrode supporting half cell having a barrier layer were obtained by firing at 1300 ° C. for 2 hours.

(7) Formation of air electrode layer As a powder material used as a raw material for LSCF, commercially available powders of La ₂ O ₃ , SrCO ₃ with purity of 99%, CoO with purity of 99% and Fe ₂ O ₃ have an element ratio of La. They were mixed to obtain _0.6 Sr _0.4 Co _0.2 Fe _0.8. Ethanol was added to the obtained powder mixture, and pulverized and mixed with a bead mill for 1 hour. Next, the pulverized and mixed powder mixture was dried and calcined at 800 ° C. for 1 hour. Ethanol was further added to the mixture after calcination, and the mixture was pulverized and mixed with a bead mill for 1 hour, and then dried. Thereafter, the mixture was subjected to a solid phase reaction at 1200 ° C. for 5 hours to obtain a powder.

  Ethanol was added to the obtained powder, and the mixture was further pulverized and mixed with a ball mill for 10 hours and then dried. The obtained powder was confirmed to be a single phase composed of perovskite by X-ray diffraction. Thereafter, pulverization was performed using a planetary ball mill while adjusting the rotation speed and the rotation time, whereby an LSCF powder for an air electrode having an average particle diameter (D50) of 0.5 μm was obtained.

  To 100 parts by mass of the LSCF powder, 3 parts by mass of ethyl cellulose as a binder and 30 parts by mass of α-terpineol as a solvent were added and mixed using a mortar. Then, it knead | mixed using the 3 roll mill (EXAKT technologies "model M-80S", roll material: Alumina), and obtained the slurry for air electrode layers.

  The air electrode layer slurry was applied to the barrier layer surface of the fuel electrode supporting half cell obtained in (6) above by screen printing, and dried at 90 ° C. for 1 hour to form a green layer for the air electrode layer. The application shape of the air electrode layer slurry is as follows.

-Sample for cross-sectional observation: 50 mm x 50 mm
-Performance evaluation sample: 10 mm x 10 mm
The fuel electrode supported half cell coated with the air electrode layer slurry was fired at 1000 ° C. for 2 hours to obtain a fuel electrode supported fuel cell single cell.

Example 2
A fuel electrode supported fuel cell single cell was produced in the same manner as in Example 1 except that 10 mol% yttria stabilized zirconia powder ("TZ10Y" manufactured by Tosoh Corporation) was used as the electrolyte layer component. Table 1 shows the average particle size (D50) of the used fuel electrode layer powder and the average particle size (D50) of the solid content contained in the fuel electrode layer paste.

Example 3
A single electrode for a fuel electrode-supported fuel cell was produced in the same manner as in Example 1 except that 8 mol% ytterbia stabilized zirconia powder was used as the electrolyte layer component. Table 1 shows the average particle size (D50) of the used fuel electrode layer powder and the average particle size (D50) of the solid content contained in the fuel electrode layer paste.

In addition, 8 mol% ytterbia stabilized zirconia powder was produced by the following method. Ytterbium chloride (III) hydrate (manufactured by Wako Pure Chemical Industries, Ltd.) and zirconium chloride (IV) (manufactured by Wako Pure Chemical Industries, Ltd.) were calcined and 8 mol% ytterbia stabilized zirconia (8YbSZ: (Yb ₂ O ₃ ) _0.08 ( ZrO ₂ ) _0.92 ). Purified water was prepared and controlled using a magnetic stirrer with a heating function so that the water temperature became 30 ° C. to dissolve the chloride. In addition, when it did not melt | dissolve even if 30 minutes passed, purified water was further added until the chloride could not be confirmed visually. After visually confirming that the chloride had dissolved, add purified water in an amount equivalent to 20% of ultrapure water that had been required for dissolution, and stir for another hour while keeping the aqueous solution at 30 ° C. Thus, the chloride was completely dissolved. The obtained aqueous solution was dropped into aqueous ammonia and the resulting precipitate was dried in a dryer at 80 ° C. to obtain a solid. The obtained solid was pulverized using an alumina mortar and pestle and then passed through a sieve having an opening of 1 mm to obtain a solid of 1 mm or less. The obtained solid material of 1 mm or less was transferred to a crucible and calcined at 800 ° C. for 1 hour. Ethanol is added to the calcined powder, zirconia balls are pulverized and mixed in a ball mill for 10 hours, dried, further crushed in a mortar, and the crushed powder is baked at 1200 ° C to obtain a powder. Obtained. In addition, about the obtained powder, ethanol was added and ball milling was performed using zirconia balls. At that time, by adjusting the diameter of the zirconia balls and the time of the ball mill, 8YbSZ having an average particle diameter of 0.42 μm. Powdered. The average particle size of the 8YbSZ powder obtained here was measured under the following conditions. Sodium pyrophosphate decahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in water to obtain a 0.2% by weight aqueous solution of sodium pyrophosphate, which was used as a dispersion medium. 8YbSZ powder was dispersed in this dispersion medium, and the particle diameter of the 8YbSZ powder was measured using a laser diffraction / scattering particle size distribution measuring apparatus (“Model number LA-920” manufactured by Horiba, Ltd.).

Comparative Example 1
In Example 1, the fuel electrode layer powder was not ball milled, that is, in the preparation of the fuel electrode layer paste, instead of NiO / 8YSZ mixed powder, nickel oxide (“High Purity Nickel Oxide” manufactured by Nikko Rica Corporation) was used. F ") and the anode support of Comparative Example 1 in the same manner except that a mixture of 36 parts by mass and 24 parts by mass of 8 mol% yttria-stabilized zirconia powder (" TZ8Y "manufactured by Tosoh Corporation) as an ion conductive component was used. Type fuel cell single cell was produced.

Test Example 1: Measurement of NiO / YSZ boundary length or NiO / YbSZ boundary length For the cross-sectional observation samples prepared in Examples 1 to 3 and Comparative Example 1, the center of the surface on which the air electrode or oxygen electrode is applied After cutting the part to have a length of 10 mm and a width of 5 mm, embedding the resin, and polishing to the center of the length part, that is, by polishing 5 mm from the end of the length: 10 mm, A resin-embedded sample for cross-sectional observation that can be observed with a width of 5 mm was prepared for the central portion of the observation sample. For observation, a field emission scanning electron microscope (“JSM-7600F” manufactured by JEOL Ltd.) was used, and 10,000 times the electrolyte layer / fuel electrode layer interface or electrolyte layer / hydrogen electrode layer interface of the resin-embedded sample for cross-sectional observation. Can be observed in the range where the electrolyte layer / fuel electrode layer interface or the electrolyte layer / hydrogen electrode layer interface is 12 μm or more, and the fuel electrode layer or hydrogen electrode layer is the electrolyte layer / fuel electrode layer interface or electrolyte layer / hydrogen. It acquired about arbitrary 10 points | pieces of the resin embedding sample for cross-sectional observation produced so that it could observe in the range of 5 micrometers or more from a polar layer interface, and did not include the same observation location. In order to facilitate the determination of NiO, YSZ, YbSZ, and holes, a reflected electron image was acquired.

  With respect to the acquired image, the boundary length between NiO and YSZ was measured using image analysis software (“Image Pro Plus version 4.0” manufactured by Media Cybernetics) as follows.

  First, the interface between the electrolyte layer and the fuel electrode layer or the hydrogen electrode layer was specified. In the acquired image, a straight line connecting two places, a place where NiO enters the electrolyte layer most (in the direction of the barrier layer) and a place where NiO enters the electrolyte layer most apart from the place by 2 μm or more. The electrolyte layer / fuel electrode layer interface or the electrolyte layer / hydrogen electrode layer interface was used.

  Next, a rectangle having a width of 10 μm is defined as one section in a region from the interface between the electrolyte layer and the fuel electrode layer or the hydrogen electrode layer to 3 μm in the direction of the fuel electrode support substrate or the hydrogen electrode support substrate. YSZ or NiO / YbSZ contact length was measured and totaled to determine the total boundary length in the section of the acquired image 1 field: 3 μm × 10 μm. This was performed on the 10 sections obtained for one cross-section observation resin-embedded sample, and the average value and standard deviation of the total boundary length of the 10 sections were taken as the average boundary length and standard deviation of the sample.

  Next, a distance of 1 μm from the interface between the electrolyte layer and the fuel electrode layer or the hydrogen electrode layer in the direction of the substrate is divided into rectangles of 3 μm × width 10 μm in the direction of the substrate, and NiO / YSZ in this range. The total border length in the section of the acquired image 1 visual field: 3 μm × 10 μm was determined by measuring and totaling the lengths in contact with each other. This was performed on the acquired 10 sections for one cross-section observation resin-embedded sample, and the average value and standard deviation of the total boundary length of the 10 sections were taken as the average boundary length and standard deviation of the sample.

  Table 1 shows the results of measurement average boundary lengths and standard deviations in the fuel electrode supported fuel cell single cells and hydrogen electrode supported electrolytic cells of Examples 1 to 3 and Comparative Example 1.

Test Example 2: Electrochemical Performance Evaluation Test With respect to the fuel electrode supported fuel cell single cell produced in Examples 1 to 3 and Comparative Example 1, the battery performance was evaluated by the following method. First, the temperature was raised to the measurement temperature (700 ° C.) at a rate of 100 ° C./hour while supplying 100 mL / min of nitrogen to the fuel electrode and 100 mL / min of air to the air electrode. After the temperature rise, the flow rate of the gas on the outlet side of the fuel electrode and the air electrode was measured with a flow meter, and it was confirmed that there was no leakage.

Next, a mixed gas of hydrogen / nitrogen = 3/97 (volume ratio) humidified at room temperature was supplied to the fuel electrode at a flow rate of 200 mL / min, and air was supplied to the air electrode at a rate of 400 mL / min. An electromotive force was generated after 10 minutes or more, and it was confirmed again that there was no leakage. Next, after simulating a fuel utilization rate of 80%, hydrogen / nitrogen = 20/80 (volume ratio) mixed gas humidified at room temperature was supplied to the fuel electrode at a flow rate of 200 mL / min, and the electromotive force was stabilized. A battery performance evaluation test using current-voltage characteristics was conducted after 10 minutes or more had elapsed. From the obtained current-voltage characteristics, a voltage at 0.2 A / cm ² was recorded. Table 1 shows the results of the battery performance evaluation tests of the examples and comparative examples.

  As shown in Table 1, as the boundary length between the stabilized zirconia particles and the nickel oxide particles in the interface region between the solid electrolyte layer and the fuel electrode functional layer is longer, the cell performance of the single cell for the solid oxide fuel cell Became clear. Specifically, in the solid oxide fuel cell according to the present invention, the overvoltage at the fuel electrode is low, the current-voltage characteristics are improved, and the power generation performance is improved. In addition, when the electrochemical cell is used as a solid oxide electrolytic cell, it is considered that efficient electrolysis is possible because the overvoltage at the hydrogen electrode is low and the power consumption is low.

Claims (7)

Having a fuel electrode layer or hydrogen electrode layer and a solid electrolyte layer,
The solid electrolyte layer contains an oxide ion conductive material as a main component,
The fuel or hydrogen electrode layer contains stabilized zirconia and nickel oxide,
In the cross section of the fuel electrode layer or the hydrogen electrode layer, the average value of the total boundary length of the stabilized zirconia and nickel oxide between 10 sections in the section from the interface with the solid electrolyte layer to 3 μm and in the section of 10 μm width Is a laminate having a standard deviation of 10 μm or less.   In the cross section of the fuel electrode layer or the hydrogen electrode layer, the average of the boundary lengths of the stabilized zirconia and nickel oxide between the 10 sections in the area of 1 μm to 4 μm from the interface with the solid electrolyte layer and within the 10 μm width section The laminate according to claim 1, wherein the laminate has a value of 25 µm or more and a standard deviation of 10 µm or less. Including the laminate according to claim 1 or 2,
The fuel electrode layer or hydrogen electrode layer is composed of a fuel electrode support substrate or hydrogen electrode support substrate and a fuel electrode functional layer or hydrogen electrode functional layer,
An electrode-supporting half cell for a solid oxide electrochemical cell, wherein a fuel electrode functional layer or a hydrogen electrode functional layer is in contact with a solid electrolyte layer.   The electrode-supporting half cell for a solid oxide electrochemical cell according to claim 3, wherein a barrier layer is disposed on the surface of the solid electrolyte layer opposite to the fuel electrode functional layer or the hydrogen electrode functional layer.   The solid oxidation of Claim 4 on the surface opposite to the fuel electrode functional layer or the hydrogen electrode functional layer of the solid electrolyte layer of the electrode-supporting half cell for a solid oxide electrochemical cell according to claim 3 A solid oxide electrochemical cell, characterized in that an air electrode layer or an oxygen electrode layer is formed on the surface of the electrode-supporting half cell for a solid electrochemical cell on the surface opposite to the solid electrolyte layer. Electrode support type single cell. Including the laminate according to claim 1 or 2,
The solid electrolyte layer comprises a solid electrolyte support substrate;
A solid electrolyte supported single cell for a solid oxide electrochemical cell, comprising a fuel electrode layer or a hydrogen electrode layer, a solid electrolyte support substrate, and an air electrode layer or an oxygen electrode layer in this order.   Furthermore, the solid electrolyte support type single cell for solid oxide type electrochemical cells of Claim 6 which contains a barrier layer between a solid electrolyte support substrate and an air electrode layer or an oxygen electrode layer.