WO2020004333A1 - Electrode for solid oxide cells, and solid oxide cell using same - Google Patents

Abstract

An electrode for solid oxide cells and a solid oxide cell, which are configured such that: an electron conductive material and an ion conductive material are contained; the mass ratio of the electron conductive material to the ion conductive material is from 75:25 to 25:75; the respective average particle diameters of primary particles in the electron conductive material and in the ion conductive material are from 1 nm to 1 μm; the film thickness of the electrode is from 0.5 μm to 50 μm; and the porosity of the electrode is from 1% by volume to 30% by volume.

Description

Electrode for solid oxide cell and solid oxide cell using the same

The present invention relates to an electrode for a solid oxide cell and a solid oxide cell using the same.

固体 Research and development are underway for the practical application of solid oxide cells for electrochemical reactions as devices that enable high-efficiency energy conversion. Representative examples of a device using a solid oxide cell include a solid oxide fuel cell and a solid oxide electrolytic cell. A solid oxide cell is formed by sandwiching a dense electrolyte mainly composed of an oxide between two porous electrodes, an air electrode and a fuel electrode.

The solid oxide cell can be used in a wide operating temperature range depending on the constituent materials and is used at 400 to 1000 ° C.

イ オ ン The ions serving as charge carriers are mainly oxide ions and protons. An electrolyte material that conducts oxide ions is called an oxide ion conductive electrolyte, and an electrolyte material that conducts protons is called a proton conductive electrolyte. Representative examples of the oxide ion conductive electrolyte include a ceria-based material, and examples of the proton conductive electrolyte include a perovskite oxide material.

Electrode conductive oxide or metal having catalytic activity is used for the electrode material (hereinafter referred to as “electron conductive material”). The electron conductive material may be used alone, but in order to expand the reaction field in the electrode, the same material as the electrolyte or the same ion as the electrolyte (“ion” refers to a conductive carrier containing oxide ions or protons) An ion-conductive material that conducts all of the ions described below) may be used as a mixture with an electron-conductive material. Generally, the reaction resistance of the electrode is reduced by mixing the electron conductive material and the ion conductive material. The reaction resistance depends on the width of the reaction field per unit area of the electrode (or the amount of the reaction active site) and the activity per reaction field.

A mixture of an electron conductive material and an ion conductive material when at least one of the materials has an average particle size of 1 μm or less is referred to as a composite, and the effect of reducing the reaction resistance of the electrode is remarkable by forming the composite. Is obtained.

Since the electrode is a porous material, it supplies gas required for an electrochemical reaction to a reaction field in the electrode, and removes gas generated by the electrochemical reaction. "Diffusion"). The resistance in the electrode caused by gas diffusion is called gas diffusion resistance. In practice, in order to sufficiently reduce the gas diffusion resistance, it is necessary to make the porosity of the electrode exceed at least 30% by volume, and the porosity is set to about 40% by volume in an actual electrode design. Often.

抵抗 The resistance obtained by combining the above-mentioned reaction resistance and gas diffusion resistance of the electrode is called electrode resistance.

As the electron conductive material for the air electrode of the solid oxide cell, a perovskite oxide material, for example, (LaSr) MnO ₃ , (LaSr) FeO ₃ , (LaSr) CoO ₃ , (LaSr) (CoFe) O ₃ or the like is there. La of the above electron conductive material can be substituted or partially substituted with other lanthanoids (Pr, Sm, Gd), and Sr can be substituted or partially substituted with other alkaline earth metals (Ca, Ba). It is.

(4) Metallic materials (Ti, Mn, Fe, Co, Ni, Cu, etc.) are used as the electron conductive material for the fuel electrode of the solid oxide cell. Metal-based materials include those reduced by gases such as hydrogen, carbon monoxide, hydrocarbons, and biofuels. For example, if NiO (oxide) is used as a manufacturing material, a solid oxide cell is constructed and when operated with the gas, NiO is reduced to Ni (metal).

重要 An important issue for the spread of solid oxide cells is the improvement of energy conversion performance per unit volume, which directly leads to cost reduction. An important factor in the energy conversion performance per unit volume of a solid oxide cell is the current per unit area of the electrode (hereinafter referred to as "current density"). Various research and development are underway.

支配 The dominant factor that determines the current density of a solid oxide cell is the above-mentioned electrode resistance. An overvoltage (difference between an equilibrium state and an operating state) occurs due to the electrochemical reaction and gas diffusion occurring at the electrode, but from the viewpoint of high efficiency operation, an electrode with a low electrode resistance that can obtain a high current density even at a low overvoltage Is required.

As research and development to date, for example, an electrode capable of obtaining a high current density by reducing an electrode resistance by combining an electron conductive material and an ion conductive material has been disclosed (Patent Document 1). . Further, in order to obtain a higher current density, a nano-sized electrode structure and an electrode material are disclosed (Patent Document 2). It is also reported that the porosity needs to be set high to obtain sufficient diffusibility (Non-Patent Document 1), and a porosity control method and its effectiveness are also disclosed (Patent Document 3). . However, there is a trade-off between the reduction of reaction resistance by expanding the reaction field and the reduction of gas diffusion resistance by securing gas diffusion paths, and as a result there is a limit to reducing electrode resistance. Had occurred.

Japanese Patent Publication No. 2005-139024 Japanese Patent Publication No. 2010-282932 Japanese Patent Publication No. 2004-119108

As described above, in order to reduce the cost of the solid oxide cell, it is necessary to drastically reduce the electrode resistance as compared with the conventional technology. However, in the above prior art, although the electrode resistance has been successfully reduced, the electrode resistance is further reduced and a higher current density is realized for the early spread and commercialization of solid oxide cells. Is required.

Accordingly, the present invention has been made in view of the above circumstances, and has as its object to provide an electrode for a solid oxide cell having a low electrode resistance, a solid oxide cell using the same, and a method for producing the same. And

SUMMARY OF THE INVENTION The present inventors have solved the above-mentioned problems in the prior art, namely, "To reduce the electrode resistance, it is necessary to expand the electrode reaction field and secure a gas diffusion path. In order to solve the problem of `` difficult '', many electrode samples were prototyped by controlling the material and structure of the electrode, and as a result of repeated performance evaluation, as the electrode material, multiple oxides with different crystal structures or When the metal material has a specific particle size, is compounded in a specific content ratio, and the electrode has a specific thickness, the porosity can be set to a lower value than before, and the porosity can be set to a specific range. As a result, the inventors have found that the electrode resistance can be drastically reduced, and have developed the present invention.

解決 In order to solve the above problems, the present invention has the following features.

(1) An electrode for a solid oxide cell, comprising an electron conductive material and an ion conductive material,
The mass ratio of the electron conductive material to the ion conductive material is 75:25 to 25:75,
The average particle size of the primary particles in each of the electron conductive material and the ion conductive material is 1 nm to 1 μm;
The electrode has a thickness of 0.5 μm to 50 μm,
An electrode for a solid oxide cell, wherein the porosity of the electrode is 1 to 30% by volume.
(2) In the solid oxide cell electrode according to the above (1), when the thickness is 0.5 μm ≦ the thickness of the electrode ≦ 1 μm, the solid oxide having a porosity of 1 to 15% by volume is used. Electrodes for object cells.
(3) In the solid oxide cell electrode according to the above (1), when the thickness of the electrode is 1 μm <the thickness of the electrode ≦ 5 μm, the porosity of the electrode is 5 to 20% by volume. Electrodes for cells.
(4) In the solid oxide cell electrode according to (1) above, when the film thickness is 5 μm <the film thickness of the electrode ≦ 25 μm, the porosity of the electrode is 7 to 25% by volume. Electrodes for cells.
(5) In the solid oxide cell electrode of the above (1), when the film thickness is 25 μm <the film thickness of the electrode ≦ 50 μm, the porosity of the electrode is 10 to 30% by volume. Electrodes for cells.
(6) The electrode for a solid oxide cell according to any one of (1) to (5) above, wherein the electrode for a solid oxide cell is a laminated structure, on an electrolyte or an ion-conductive material intermediate layer formed on the electrolyte. A laminated structure characterized by being formed.
(7) A laminated structure, wherein a porous layer having a higher porosity than the solid oxide cell electrode is provided on the solid oxide cell electrode of the laminated structure according to (6). A laminated structure characterized by being laminated.
(8) A solid oxide cell comprising an electrolyte, an air electrode and a fuel electrode sandwiching the electrolyte, and having the laminated structure according to (6) or (7) on the air electrode side. A solid oxide cell, characterized in that:
(9) A solid oxide cell comprising an electrolyte, an air electrode and a fuel electrode sandwiching the electrolyte, and having the laminated structure according to the above (6) or (7) on the fuel electrode side A solid oxide cell, characterized in that:
In this specification, when the numerical range is indicated by using “to”, the numerical value at both ends is included.

According to the present invention, an electrode having a low electrode resistance can be provided. Further, according to the present invention, a solid oxide cell realizing a high current density can be provided.

FIG. 1 is a schematic cross-sectional view of a laminated structure of an electrode and an electrolyte according to an embodiment. FIG. 1 is a schematic cross-sectional view of a laminated structure of a laminated electrode, an intermediate layer, and an electrolyte according to an embodiment. FIG. 1 is a schematic cross-sectional view of a solid oxide cell according to an embodiment. 9 is a scanning electron microscope (SEM) image of a cross section of the electrode of Example 3. A binarized image (white part: material, black part: pores) obtained by image analysis of the cross section of the electrode of Example 3.

に As described above, for the rapid spread and commercialization of solid oxide cells, it is necessary to reduce the electrode resistance, which is directly related to cost. The electrode resistance is the combined resistance of the reaction resistance and the gas diffusion resistance, but there is a trade-off between expanding the reaction field to reduce the reaction resistance and securing a gas diffusion path to reduce the gas diffusion resistance. For this reason, there has been a limit in reducing the electrode resistance. Therefore, the present inventors have proposed that the solid oxide cell electrode be a composite of a plurality of oxides or metal oxides at a specific content ratio to have a specific particle diameter, a specific film thickness, and a specific porosity. As a result, it has been found that the reaction resistance and the gas diffusion resistance can be reduced at the same time, and as a result, the electrode resistance can be dramatically reduced.

In this specification, when the numerical range is indicated by using “to”, the numerical value at both ends is included.

Hereinafter, an electrode for a solid oxide cell of the present invention, a solid oxide cell using the same, and a method of manufacturing the same will be described based on embodiments and examples.

FIG. 1 schematically shows a cross section of an electrode according to an embodiment of the present invention. The electrode of this embodiment is porous and has pores for gas diffusion (porous electrode 1). The porous electrode 1 includes an electron conductive material 3 and an ion conductive material 4. The porosity of the porous electrode is 1 to 30% by volume.

In FIG. 1, when the electrode to be manufactured is an air electrode, the electron conductive material 3 is an electron conductive material for an air electrode, while when the electrode to be manufactured is a fuel electrode, the electron conductive material 3 is , An electron conductive material for fuel electrodes.

多孔 As shown in FIG. 1, the porous electrode 1 is formed on an electrolyte 2 which is an ion conductive material. The electrolyte 2 has a dense body layer for preventing gas cross leak. The entire electrolyte 2 may be a dense body. The relative density of the dense body layer of the electrolyte 2 is 90 to 100% by volume, more preferably 97 to 100% by volume, and particularly preferably 98 to 100% by volume. This is because the gas cross leak prevention function can be further improved. Further, the thickness of the dense body layer of the electrolyte 2 is 0.1 μm to 1 mm, more preferably 0.5 μm to 100 μm, and particularly preferably 1 μm to 30 μm. This is because the resistance of the dense body layer of the electrolyte 2 can be reduced while maintaining the gas cross leak prevention function. In order to reduce the thickness of the electrolyte 2 while preventing gas crisp leakage, it is desirable that the entire electrolyte 2 be a dense body.

FIG. 2 schematically shows a cross-sectional view of the electrode according to the embodiment of the present invention. When the chemical stability of the mutual material between the porous electrode 1 and the electrolyte 2 is low, an intermediate layer 5 having a reaction preventing function is used between the porous electrode 1 and the electrolyte 2, and the porous electrode 1 is placed on the intermediate layer 5. Formed. The intermediate layer 5 is an ion conductive material.

In addition, as shown in FIG. 2, a porous electrode 6 having a higher porosity than the porous electrode 1 is formed on the porous electrode 1 in order to improve the gas diffusion property and the electrical current collecting property. I do. Thereby, the porous electrode 1 can be formed as a specialized electrode (referred to as a functional layer, a catalyst layer, or an active layer) for reducing the electrode resistance.

The electron conductive material for the air electrode refers to a material that can be used in a high-temperature oxidizing atmosphere, has catalytic activity for the oxidation or reduction reaction of the air electrode side gas, and has a property of conducting electrons. The electron conductive material for the air electrode is not particularly limited, and examples thereof include oxides such as (LaSr) MnO ₃ , (LaSr) FeO ₃ , (LaSr) CoO ₃ , and (LaSr) (CoFe) O _3. Can be The electron conductive oxide for the air electrode may be a single type or a combination of two or more types.

As the electron conductive material for the air electrode, the following general formula (1):
_{A 1-x B x C y} O 3-z (1)
A perovskite oxide material represented by

In the general formula (1), A includes one or more of Y, La, Ce, Pr, Sm, and Gd, and preferably includes one or more of La, Sm, and Gd. Have been. B contains at least one of Sr, Ca and Ba, and preferably contains Sr. C contains one or more of Cr, Mn, Fe, Co, Ni, and Cu, and preferably contains one or more of Mn, Fe, and Co. Further, x is 0.20 to 0.60, preferably 0.25 to 0.50, particularly preferably 0.30 to 0.50. Further, y is 0.95 to 1.15, preferably 1.00 to 1.10, particularly preferably 1.00 to 1.05. Z is -1.00 to 1.00, preferably -0.50 to 0.50, and particularly preferably -0.30 to 0.30.

The perovskite-type oxide material represented by the general formula (1) may be used alone or in combination of two or more.

The ion conductive material refers to a material having a property of conducting ions that are oxidized or reduced at the air electrode. The ion conductive material is not particularly limited. For example, stabilized zirconia doped with a metal element such as Al, Ca, Sc, Y, and Ce; metals such as Sc, Y, La, Sm, Gd, and Yb Element-doped ceria; lanthanum gallate doped with a metal element such as Mg, Al, Ca, Sr, Cr, Mn, Fe, Co, Ni; Mg, Al, Ca, Sr, Cr, Mn, Fe , Lanthanum aluminate doped with a metal element such as Co, Ni; lanthanum scandinate doped with a metal element such as Mg, Al, Ca, Sr, Cr, Mn, Fe, Co, Ni; Y, Nb Oxide doped with a metal element such as, Gd, W: pyrochlore-type oxides such as lanthanum zirconate, samarium zirconate, and gadolinium zirconate; S , Strontium zirconate doped with a metal element such as Cr, Mn, Fe, Co, Ni, Y, In, La, Pr, Nd, Sm, Gd, Yb, strontium serrate, strontium zirconate serrate, barium Perovskite-type oxides such as zirconate, barium serate, and barium zirconate serate; and the like. The ion conductive material may be used alone or in combination of two or more.

As the ion conductive material, stabilized zirconia, doped ceria, doped barium zirconate, and doped barium zirconate serate are preferable.

An electron conductive material for an anode refers to a material that can be used in a high-temperature reducing atmosphere, has catalytic activity for oxidation or reduction of an anode electrode gas, and has a property of conducting electrons. Sometimes it contains oxides that are reduced to metals. The electron conductive material for the fuel electrode is not particularly limited, and examples thereof include oxides such as iron oxide, nickel oxide, and copper oxide. The electron conductive material for the fuel electrode may be a single type or a combination of two or more types.

ニ ッ ケ ル As the electron conductive material for the fuel electrode, nickel oxide is preferable.

The electrode of the present invention is a porous body in which an electron conductive material and an ion conductive material are combined. The mass ratio between the electron conductive material and the ion conductive material in the electrode (electron conductive material: ion conductive material) is 75:25 to 25:75, preferably 70:30 to 30:70, and particularly preferably 60. : 40 to 40:60. When the mass ratio between the electron conductive material and the ion conductive material in the electrode is within the above range, the number of contact points between the electron conductive material and the ion conductive material increases, so that the reaction field is expanded and the electrode resistance is increased. Lower.

Other material components other than the electron conductive material and the ion conductive material contained in the electrode of the present invention, when the total mass of the electron conductive material and the ion conductive material is 100 parts by mass, the other material component is It is in the range of 0 to 20 parts by mass.

平均 The average particle size of the primary particles in the electron conductive material and the ion conductive material in the electrode of the present invention is 1 nm to 1 μm, preferably 5 nm to 0.5 μm, particularly preferably 10 nm to 0.2 μm. When the average particle diameter of the primary particles in the electron conductive material and the ion conductive material in the electrode is within the above range, the contact point between the electron conductive material and the ion conductive material increases, and the specific surface area in the electrode increases. The increase increases the reaction field and lowers the electrode resistance.

In the present invention, the average particle size of the primary particles is calculated by X-ray diffraction (eg, SmartLab, manufactured by Rigaku Corporation) and Scherrer's formula (Scherrer constant: 0.9).

膜厚 The thickness of the electrode of the present invention is 0.5 μm to 50 μm, preferably 0.5 μm to 25 μm, particularly preferably 0.5 μm to 5 μm. When the thickness of the electrode is within the above range, the gas diffusion resistance is reduced, so that the electrode resistance is reduced.

The porosity of the electrode of the present invention is 1 to 30% by volume, preferably 2 to 25% by volume, particularly preferably 3 to 20% by volume. When the porosity of the electrode is in the above range, the occupancy of the electron conductive material and the ion conductive material in the electrode per space is increased, and the reaction field is expanded, so that the electrode resistance is reduced.

In the electrode of the present invention, when the film thickness and the porosity are in the following ranges, the electrode resistance is further reduced.
(I) When 0.5 μm ≦ the thickness of the electrode ≦ 1 μm, the porosity of the electrode is 1 to 15% by volume, preferably 2 to 13% by volume, and particularly preferably 3 to 10% by volume.
(II) When 1 μm <the film thickness of the electrode ≦ 5 μm, the porosity of the electrode is 5 to 20% by volume, preferably 7 to 18% by volume, particularly preferably 10 to 15% by volume.
(III) When 5 μm <the thickness of the electrode ≦ 25 μm, the porosity of the electrode is 7 to 25% by volume, preferably 8 to 20% by volume, and particularly preferably 12 to 18% by volume.
(IV) When 25 μm <the thickness of the electrode ≦ 50 μm, the porosity of the electrode is 10 to 30% by volume, preferably 12 to 25% by volume, particularly preferably 15 to 20% by volume.

電極 The electrode of the present embodiment is suitably manufactured by the following manufacturing method.

電極 The electrode of the present invention, that is, the porous electrode 1 is formed on the electrolyte 2 or the intermediate layer 5. The electrolyte 2 is generally a dense body to prevent gas leakage. The intermediate layer 5 may be either a dense body or a porous body, but preferably has a high relative density in order to enhance the reaction prevention function. Specifically, it is preferably from 60 to 100% by volume, more preferably from 70 to 100% by volume, and particularly preferably from 80 to 100% by volume.

原 As a raw material of the porous electrode 1, an oxide powder material is used. The average particle size of the primary particles when the electrode is formed can be controlled by the particle size of the oxide powder material, the dispersion state, the firing temperature, or the combination of the materials to be composited.

When the porous electrode 1 is formed, the amount of the binder, the plasticizer, or the dispersant or the sintering temperature is changed, or carbon, cellulose, or a polymer-based pore-forming agent is additionally mixed to form the porous electrode. The porosity of 1 can be controlled.

The method for producing the porous electrode 1 includes, for example, a step of applying a first slurry on a porous support, and then baking it at a first temperature to form an electrolyte 2, and a step of applying a second slurry on the electrolyte 2. A step of forming the porous electrode 1 by applying and then firing at a second temperature. When the intermediate layer 5 is used, for example, a step of applying the first slurry on a porous support and then firing at a first temperature to form the electrolyte 2, A step of applying a slurry and then firing at a third temperature to form an intermediate layer 5; and applying a second slurry onto the intermediate layer 5 and then firing at a second temperature to form the porous electrode 1. The step of performing

The first slurry coating method includes a screen printing method, a spray coating method, a transfer method, a dip coating method, and the like. In any of the coating methods, a coating film having a high molding density can be obtained by optimizing the particle dispersibility of the electrolyte material in the first slurry. The sintering of the coating film proceeds by firing at the first temperature. The thickness of the electrolyte 2 obtained after firing is preferably 0.5 to 30 μm.

In order to reduce the electric resistance, it is preferable to make the electrolyte 2 as thin as possible. On the other hand, extremely thinning causes gas leakage due to defects in the electrolyte 2. Therefore, it is appropriate that the electrolyte 2 has a film thickness of 0.5 μm or more to prevent defects, and a film thickness of 30 μm or less that allows the electric resistance of the electrolyte 2 to be 以下 or less of the total electric resistance of the solid oxide cell.

焼 成 The firing temperature of this coating film, that is, the first temperature, is preferably 1250 to 1500 ° C, more preferably 1300 to 1450 ° C, and particularly preferably 1350 to 1400 ° C. This is because the sintering of the coating film proceeds sufficiently at a firing temperature of 1250 ° C. or more, and a dense electrolyte is obtained. Further, at a firing temperature of 1500 ° C. or less, diffusion of elements and volatilization of elements constituting the electrolyte 2 are suppressed. The firing time of the coating film is preferably 1 to 8 hours, more preferably 2 to 6 hours, and particularly preferably 3 to 4 hours.

塗布 Examples of the method for applying the second slurry include a screen printing method, a spray coating method, a transfer method, and a dip coating method. The sintering of this coating film proceeds by firing at the third temperature. The thickness of the porous electrode 1 obtained after firing is preferably 0.5 to 50 μm.

In the step of forming the porous electrode 1, for example, an air electrode is formed on the electrolyte 1 or the intermediate layer 5. The porous electrode 1 preferably contains a perovskite oxide material as an electron conductive material.

The porous electrode 1 is a material in which an electron conductive material and an ion conductive material are combined. The second temperature, which is the firing temperature of the porous electrode 1, is preferably from 700 to 1200 ° C, more preferably from 800 to 1100 ° C, and particularly preferably from 850 to 1050 ° C. The firing time is preferably 0.5 to 8 hours, more preferably 1 to 6 hours, and particularly preferably 1 to 3 hours.

The third slurry coating method includes a screen printing method, a spray coating method, a transfer method, a dip coating method, and the like. In any of the coating methods, a coating film having a high molding density can be obtained by optimizing the particle dispersibility of the intermediate layer material in the third slurry. The sintering of the coating film proceeds by firing at the third temperature, and the thickness of the intermediate layer 5 obtained after firing is desirably 0.1 to 15 μm.

中間 In order to reduce the electric resistance, it is preferable to make the intermediate layer 5 as thin as possible. On the other hand, an extremely thin film impairs the reaction preventing function of the intermediate layer 5. Therefore, the thickness of the intermediate layer 5 is 0.1 μm or more in order to maintain the reaction preventing function, and the thickness of the intermediate layer 5 is 15 μm or less that can reduce the electric resistance of the intermediate layer 5 to １ ／ or less of the total electric resistance of the solid oxide cell. Is appropriate.

焼 成 The firing temperature of the coating film, that is, the third temperature, is preferably from 1000 to 1400 ° C, more preferably from 1100 to 1350 ° C, and particularly preferably from 1150 to 1300 ° C. This is because a good sintering state can be obtained, and the influence of mutual diffusion of elements with the electrolyte 2 can be suppressed. The firing time of the coating film is preferably 0.5 to 4 hours, more preferably 1 to 3 hours, and particularly preferably 1 to 2 hours.

FIGS. 3A and 3B schematically show cross-sectional views of the solid oxide cell according to the embodiment of the present invention. The solid oxide cell according to the embodiment of the present invention includes the porous electrode 7, the electrolyte 2, and the porous electrode 1 of the present invention. Further, an intermediate layer 5 as a reaction preventing intermediate layer and a porous electrode 6 for improving gas diffusibility and electric current collecting performance may be provided.

When the porous electrode 1 is an air electrode, for example, the first slurry is applied on the porous electrode 7 that is a fuel electrode, and then the first temperature is changed to the first temperature. And forming a porous electrode 1 by applying a second slurry on the electrolyte 2 and then firing at a second temperature. When the intermediate layer 5 is used, for example, a step of applying the first slurry on the porous electrode 1 and then baking it at the first temperature to form the electrolyte 2, and a step of applying the third slurry on the electrolyte 2 And then baking at a third temperature to form an intermediate layer 5, and applying a second slurry onto the intermediate layer 5 and then baking at a second temperature to form the porous electrode 1. It has a process.

As shown in FIG. 3B, using a material different from the porous electrode 7 as the support 8, the porous electrode 7 is formed on the support 8, and the electrolyte 2 is formed on the porous electrode 7. , The intermediate layer 5, the porous electrode 1, and, if necessary, the porous electrode 6 may be sequentially formed to produce a solid oxide cell. The air electrode may be either the porous electrode 1 or the porous electrode 7, and the fuel electrode may be an electrode that is not the air electrode. In the solid oxide cell of the above embodiment, the porous electrode 1 is described as an air electrode.

The support 8 used in the step of forming the electrolyte 2 is preferably a porous body. This is because good gas diffusivity can be realized. The porosity of the porous support 8 is, for example, 10 to 60% by volume. As a method for producing the support 8, uniaxial pressure molding, injection molding, extrusion molding, cast molding, or the like can be employed, but is not particularly limited. The shape of the porous support 8 may be a flat plate shape or a tube shape, but is not particularly limited. Examples of the material of the support 8 include oxides such as alumina and zirconia, and heat-resistant metals. As a fuel electrode, a mixture of an ion conductive material and an oxide represented by MeO _α (Me = Ti, Mn, at least one of Fe, Co, Ni, Cu, 0.8 ≦ α ≦ 2.2) is used. Is also good.

Weight ratio of the ion conductive material and MeO oxide represented by _alpha, the ion conducting material: oxide represented by _{MeO α = 30: 70 ~ 70} : 30 is a measure of the preferred range. The mixing ratio by weight, the ion conductive material: oxide represented by _{MeO α = 35: 65 ~ 65} : 35 , more preferably, the ion conductive material: oxide = 40 represented by MeO _alpha: 60 ~ 60 : 40 is particularly preferred.

(4) A first slurry as an electrolyte material is applied on the fuel electrode, and the fuel electrode and the applied material are co-sintered at a first temperature to obtain a thin-film dense electrolyte layer. That is, a laminate including the electrolyte 2 that is a thin-film dense electrolyte layer and the porous electrode 7 that is a fuel electrode formed on one surface of the electrolyte 2 is obtained. By co-sintering the fuel electrode and the coating material, the electrolyte can be shrunk together with the fuel electrode, and a dense electrolyte layer having a high relative density can be obtained.

The method for applying the first slurry and the film thickness of the electrolyte 2 are the same as the method for applying the first slurry and the film thickness of the electrolyte 2 in the electrode manufacturing method. The preferred range of the first temperature, which is the co-sintering temperature of the fuel electrode and the electrolyte 2, and the reason therefor are the same as the preferred range of the firing temperature of the coating film, which is the material of the electrolyte 2, in the electrode manufacturing method and the reason therefor. is there. Further, the preferable range of the co-sintering time and the reason therefor are the same as the preferable range of the firing time of the coating film which is the material of the electrolyte 2 in the electrode manufacturing method and the reason therefor.

A third slurry as an intermediate layer material is applied on the electrolyte 2 and the applied material is sintered at a third temperature to obtain a thin film intermediate layer. That is, a laminate including the intermediate layer 5 as a thin film intermediate layer and the porous electrode 7 as a fuel electrode formed on one surface of the electrolyte 2 is obtained.

The method of applying the third slurry and the thickness of the intermediate layer 5 are the same as the method of applying the third slurry and the film thickness of the intermediate layer 5 in the electrode manufacturing method. The preferable range of the third temperature, which is the firing temperature of the intermediate layer 5, and the reason therefor are the same as the preferable range of the firing temperature of the coating film, which is the material of the intermediate layer 5, in the method for manufacturing an electrode, and the reason therefor. Further, the preferable range of the baking time and the reason therefor are the same as the preferable range of the baking time of the coating film, which is the material of the intermediate layer 5 in the method for manufacturing an electrode, and its reason.

In the step of forming the porous electrode 1, the porous electrode 1 as an air electrode is formed on the electrolyte 2 or the intermediate layer 5. The oxide contained in the porous electrode 1 and the second temperature that is the firing temperature of the porous electrode 1 are the same as in the method for manufacturing the electrode. Further, a porous electrode 6 having a higher porosity than the porous electrode 1 may be formed on the porous electrode 1 in order to improve the gas diffusion property and the electrical current collecting property. The material and porosity of the porous electrode 6 are different from those of the porous electrode 1, but the manufacturing method is the same as that of the porous electrode 1. In the solid oxide cell, an electrolyte 2, an intermediate layer 5 (if necessary), a porous electrode 1, and a porous electrode 6 (if necessary) are formed on a porous electrode 7 as a support. Device. This porous electrode 1 is a product of the present invention.

Next, the present invention will be described more specifically with reference to examples, but these are merely examples and do not limit the present invention.

空 気 Air electrodes having different ratios of the electron conductive material and the ion conductive material, the average particle diameter of the primary particles, the film thickness, and the porosity were prepared according to the following procedures. Here, the oxide powder material used as the raw material of the air electrode was produced by a spray pyrolysis method.

<Synthesis of oxide powder material by spray pyrolysis>
The spray pyrolysis method is one of the techniques that can synthesize a nano-sized oxide powder material. Although a single oxide powder material can be synthesized, an oxide powder material in which two or more oxides are compounded can also be synthesized. At this time, a good dispersion state can be obtained in the two or more kinds of composite oxides. Another feature is that the primary particle size can be controlled in a wide range. Hereinafter, the synthesis of the oxide powder material by the spray pyrolysis method in Examples will be described.

In the spray pyrolysis process, an aqueous solution for spraying containing a metal salt of an electron conductive material source for an air electrode and a metal salt of an ion conductive material source is prepared, and the aqueous solution for spraying is atomized by ultrasonic vibration. Then, the atomized aqueous solution for spraying is introduced into a heating furnace to obtain an oxide powder material for an air electrode.

By appropriately selecting the concentration ratio of each metal element contained in the aqueous solution for spraying, the composition ratio of various metal elements constituting the primary particles of the electron conductive material for the air electrode and the primary particles of the ion conductive material Was adjusted.

The aqueous solution for atomization in the atomizer is atomized by ultrasonic vibration (1.75 MHz), and then the atomized aqueous solution for atomization is caused to flow by the air of a carrier gas through a pipe connected to the atomizer. Was introduced. The metal salt of the electron conductive material source for the air electrode and the metal salt of the ion conductive material source in the aqueous solution for spraying were thermally decomposed and oxidized to obtain an oxide powder material for the air electrode. As the heating furnace, a four-stage electric furnace (with a furnace temperature of 300, 500, 700, and 900 ° C. from the previous stage, and a furnace heating time of 8 seconds, 8 seconds, 8 seconds, and 8 seconds from the previous stage) was used.
<Preparation of aqueous solution for spraying>
(1) Spray aqueous solution s1
18.98 g of samarium nitrate hexahydrate, 8.01 g of strontium nitrate, 22.02 g of cobalt nitrate hexahydrate, and 8.45 g of cerium nitrate hexahydrate are weighed, dissolved in pure water, and then dissolved in pure water. Was adjusted to 1000 ml to prepare an aqueous solution s1 for spraying. The spray aqueous solution s1 is pyrolyzed by spraying to obtain 0.1 mol per liter of 80 parts by mass Sm _0.5 Sr _0.5 Co ₃ (hereinafter, SSC) -20 parts by mass Ce _0.8 Sm _0.2 O _1.9 (hereinafter, SDC) can be synthesized.
(2) Aqueous solution for spraying s2
17.49 g of samarium nitrate hexahydrate, 6.82 g of strontium nitrate, 18.76 g of cobalt nitrate hexahydrate and 12.34 g of cerium nitrate hexahydrate are weighed, and otherwise the same method as in the aqueous solution for spraying s1 Thus, an aqueous solution s2 for spraying was prepared. By spray pyrolysis of the aqueous solution s2 for spraying, 70 parts by mass of SSC-30 parts by mass of SDC at 0.1 mol per liter can be synthesized.
(3) Aqueous solution for spraying s3
16.07 g of samarium nitrate hexahydrate, 5.70 g of strontium nitrate, 15.67 g of cobalt nitrate hexahydrate, and 16.04 g of cerium nitrate hexahydrate were weighed, and otherwise the same as the aqueous solution for spraying s1 An aqueous solution s3 for spraying was prepared by the method. By subjecting the aqueous solution for spray s3 to spray pyrolysis, 60 parts by mass SSC-40 parts by mass SDC of 0.1 mol per liter can be synthesized.
(4) Aqueous solution for spraying s4
14.72 g of samarium nitrate hexahydrate, 4.63 g of strontium nitrate, 12.73 g of cobalt nitrate hexahydrate and 19.54 g of cerium nitrate hexahydrate were weighed, and otherwise the same as the aqueous solution s1 for spraying An aqueous solution s4 for spraying was prepared by the method. By spray pyrolysis of the aqueous solution for spray s4, 50 parts by mass SSC-50 parts by mass SDC of 0.1 mol per liter can be synthesized.
(5) Spray aqueous solution s5
13.44 g of samarium nitrate hexahydrate, 3.61 g of strontium nitrate, 9.94 g of cobalt nitrate hexahydrate, and 22.88 g of cerium nitrate hexahydrate were weighed, and otherwise the same as the aqueous solution for spraying s1 An aqueous solution s5 for spraying was prepared by the method. By subjecting the aqueous solution for spray s5 to spray pyrolysis, 0.1 mol per 1 L of 40 parts by mass SSC-60 parts by mass SDC can be synthesized.
(6) Spray aqueous solution s6
12.22 g of samarium nitrate hexahydrate, 2.64 g of strontium nitrate, 7.27 g of cobalt nitrate hexahydrate and 26.06 g of cerium nitrate hexahydrate were weighed, and otherwise the same as the aqueous solution for spraying s1 An aqueous solution s6 for spraying was prepared by the method. By spray pyrolysis of the aqueous solution s6 for spraying, 30 parts by mass SSC-70 parts by mass SDC of 0.1 mol per liter can be synthesized.
(7) Spray aqueous solution s7
11.06 g of samarium nitrate hexahydrate, 1.72 g of strontium nitrate, 4.74 g of cobalt nitrate hexahydrate, and 29.08 g of cerium nitrate hexahydrate were weighed, and otherwise the same as the aqueous solution s1 for spraying An aqueous solution s7 for spraying was prepared by the method. By subjecting the aqueous solution for spray s7 to spray pyrolysis, 20 parts by mass SSC-80 parts by mass SDC of 0.1 mol per liter can be synthesized.
(8) Aqueous solution for spraying s8
14.93 g of gadolinium nitrate hexahydrate, 4.61 g of strontium nitrate, 12.68 g of cobalt nitrate hexahydrate, and 19.61 g of cerium nitrate hexahydrate were weighed, and otherwise the same as the aqueous solution s1 for spraying An aqueous solution s8 for spraying was prepared by the method. The spray aqueous solution s8
Is spray-pyrolyzed to give 50 parts by mass of Gd _0.5 Sr _0.5 Co ₃ (hereinafter referred to as GSC) -50 parts by mass of Ce _0.8 Gd _0.2 O _1.9 (hereinafter referred to as 0.1 mol / L). , GDC).
(9) Aqueous solution for spraying s9
11.43 g of lanthanum nitrate hexahydrate, 3.73 g of strontium nitrate, 12.63 g of manganese nitrate hexahydrate, 19.45 g of cerium nitrate hexahydrate and 5.05 g of gadolinium nitrate hexahydrate were weighed, Except for this, an aqueous solution for spraying s9 was prepared in the same manner as for the aqueous solution for spraying s1. By subjecting the aqueous solution s9 for spraying to spray pyrolysis, 50 parts by mass of La _0.6 Sr _0.4 MnO ₃ (hereinafter, LSM) -50 parts by mass of GDC can be synthesized at 0.1 mol per liter.
(10) Spray aqueous solution s10
25.98 g of lanthanum nitrate hexahydrate, 8.47 g of strontium nitrate, 5.82 g of cobalt nitrate hexahydrate, and 32.32 g of iron nitrate nonahydrate were weighed, and otherwise the same as the aqueous solution s1 for spraying An aqueous solution s10 for spraying was prepared by the method. By decomposing thermal spray to the spray aqueous solution s10, _La 0.6 _Sr of 0.1mol per _{1L 0.4 Co 0.2 Fe 0.8 O 3} ( hereinafter, LSCF) can be synthesized.

<Preparation of oxide powder material>
(1) oxide powder material p1
Using the spray aqueous solution s1, spray pyrolysis was performed by an ultrasonic spray pyrolysis method to obtain an oxide powder material p1 of SSC-SDC.
(2) oxide powder material p2
Using the sprayed aqueous solution s2, an SSC-SDC oxide powder material p2 was obtained in the same manner as the oxide powder material p1.
(3) oxide powder material p3
Using the spray aqueous solution s3, an SSC-SDC oxide powder material p3 was obtained in the same manner as the oxide powder material p1.
(4) oxide powder material p4
An oxide powder material p4 of SSC-SDC was obtained in the same manner as for the oxide powder material p1, using the spray aqueous solution s4.
(5) oxide powder material p5
Using the spray aqueous solution s5, an SSC-SDC oxide powder material p5 was obtained in the same manner as the oxide powder material p1.
(6) oxide powder material p6
Using the spray aqueous solution s6, an oxide powder material p6 of SSC-SDC was obtained in the same manner as for the oxide powder material p1.
(7) oxide powder material p7
Using the spray aqueous solution s7, an SSC-SDC oxide powder material p7 was obtained in the same manner as for the oxide powder material p1.
(8) oxide powder material p8
GSC-GDC oxide powder material p8 was obtained in the same manner as for oxide powder material p1, using the spray aqueous solution s8.
(9) oxide powder material p9
Using the spray aqueous solution s9, an oxide powder material p9 of LSM-GDC was obtained in the same manner as for the oxide powder material p1.
(10) oxide powder material p10
An LSCF oxide powder material p10 was obtained in the same manner as for the oxide powder material p1, using the spray aqueous solution s10.

X-ray diffraction analysis of the seven types of SSC-SDC oxide powder materials revealed that any of the SSC-SDC oxide powder materials showed diffraction peaks that could be identified as SSC and SDC, Was confirmed to be a powder material containing SSC and SDC. Further, when an X-ray diffraction analysis of the GSC-GDC oxide powder material was performed, diffraction peaks that could be identified as GSC and GDC were observed, and it was confirmed that the powder material contained crystalline GSC and GDC. Was. Further, when an X-ray diffraction analysis of the LSM-GDC oxide powder material was performed, a diffraction peak that can be identified as LSM and GDC was observed, and it was confirmed that the powder material contained crystalline LSM and GDC. Was. X-ray diffraction analysis of the LSCF oxide powder material showed a diffraction peak that could be identified as LSCF, confirming that the powder material contained crystalline LSCF.

<Commercially available oxide powder material>
Ce _0.9 Gd _0.1 O _1.95 (CGO 90/10, UHSA, manufactured by Solvay SpecialChem Japan) was used as a commercially available GDC.

<Preparation of electrode>
A mixture of the above oxide powder material, ethyl cellulose, plasticizer, dispersant, and α-terpineol was kneaded in a kneader at room temperature for 1 minute and 30 seconds to obtain an electrode slurry. . Next, the electrode slurry was formed on both surfaces of a CGO 90/10 sintered body pellet by a screen printing method. The CGO90 / 10 sintered body pellet was obtained by subjecting 2.2 g of CGO90 / 10 powder to uniaxial press molding at 20 MPa using a 26 mm diameter carbide die, followed by firing at 1350 ° C. for 3 hours. Next, the electrode was obtained by firing under predetermined firing conditions. Here, the control of the electrode film thickness was performed by changing the mesh thickness used for screen printing. The porosity was controlled by changing the mass of ethyl cellulose with respect to the mass of the oxide powder material.

<Preparation of electrode as an example>
(1) Example 1
The oxide powder material p2 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Example 1 was obtained by forming on both surfaces of a CGO90 / 10 sintered body pellet by screen printing using a mesh for 20 μm, followed by firing at 950 ° C. for 1 hour to obtain an electrode of Example 1.
(2) Example 2
The oxide powder material p3 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Example 3 was obtained by forming on both surfaces of the CGO 90/10 sintered pellet by screen printing with a mesh for 20 μm and then firing at 950 ° C. for 1 hour to obtain an electrode of Example 3.
(3) Example 3
The oxide powder material p4 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Example 3 was obtained by forming on both surfaces of the CGO 90/10 sintered pellet by screen printing with a mesh for 20 μm and then firing at 950 ° C. for 1 hour to obtain an electrode of Example 3.
(4) Example 4
The oxide powder material p5 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Example 4 was obtained by forming both surfaces on the CGO 90/10 sintered pellets by screen printing using a mesh for 20 μm and firing at 950 ° C. for 1 hour.
(5) Example 5
The oxide powder material p6 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Example 5 was obtained by forming on both surfaces of the CGO 90/10 sintered pellet by screen printing using a mesh for 20 μm, followed by firing at 950 ° C. for 1 hour to obtain an electrode of Example 5.
(6) Example 6
The oxide powder material p4 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Example 6 was obtained by forming on both sides of the CGO 90/10 sintered pellet by screen printing using a mesh for 3 μm and firing at 950 ° C. for 1 hour to obtain an electrode of Example 6.
(7) Example 7
The oxide powder material p8 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Example 7 was obtained by forming on both surfaces of the CGO 90/10 sintered pellet by screen printing using a mesh for 20 μm, followed by firing at 950 ° C. for 1 hour to obtain an electrode of Example 7.
(8) Example 8
The oxide powder material p9 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Example 8 was obtained by forming on both surfaces of the CGO90 / 10 sintered pellet by screen printing using a mesh for 20 μm, and then firing at 1150 ° C. for 1 hour to obtain an electrode of Example 8.
(9) Embodiment 9
An oxide powder material in which the oxide powder material p10 and CGO 90/10 were mixed at a mass ratio of 50:50 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the mixed oxide powder material. The electrode of Example 9 was obtained by forming on both surfaces of the CGO 90/10 sintered pellets by screen printing using a mesh for 20 μm and firing at 950 ° C. for 1 hour to obtain an electrode of Example 9. (10) Example 10
An oxide powder material in which the oxide powder material p10 and CGO 90/10 were mixed at a mass ratio of 50:50 was used. 100 parts by mass of the mixed oxide powder material was molded on both surfaces of a CGO 90/10 sintered pellet by screen printing using a 3 μm mesh with ethyl cellulose as 1 part by mass, and then fired at 950 ° C. for 1 hour. Thus, an electrode of Example 10 was obtained.
(11) Embodiment 11
The oxide powder material p4 was used. Ethyl cellulose was used in an amount of 3 parts by mass based on 100 parts by mass of the oxide powder material. The electrode of Example 11 was obtained by forming both surfaces on the CGO 90/10 sintered pellets by screen printing using a mesh for 40 μm, followed by firing at 950 ° C. for 1 hour to obtain an electrode of Example 11.
(12) Example 12
The oxide powder material p4 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrodes of Example 12 were obtained by forming both surfaces on the CGO 90/10 sintered pellets by screen printing using a mesh for 10 μm and then firing at 950 ° C. for 1 hour.

<Production of an electrode as a comparative example>
(1) Comparative Example 1
The oxide powder material p1 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Comparative Example 1 was obtained by forming on both surfaces of the CGO 90/10 sintered pellet by screen printing with a mesh for 20 μm and firing at 950 ° C. for 1 hour.
(2) Comparative example 2
The oxide powder material p7 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. The electrode of Comparative Example 2 was obtained by forming both surfaces on the CGO 90/10 sintered pellets by screen printing using a mesh for 20 μm, followed by firing at 950 ° C. for 1 hour.
(3) Comparative example 3
The oxide powder material p4 was used. Ethyl cellulose was used in an amount of 8 parts by mass based on 100 parts by mass of the oxide powder material. The electrode of Comparative Example 3 was obtained by forming on both surfaces of a CGO 90/10 sintered pellet by screen printing using a mesh for 20 μm and firing at 950 ° C. for 1 hour.
(4) Comparative example 4
The oxide powder material p4 was used. Ethyl cellulose was 1 part by mass with respect to 100 parts by mass of the oxide powder material. An electrode of Comparative Example 4 was obtained by forming both surfaces on the CGO 90/10 sintered pellet by screen printing using a mesh for 60 μm and then firing at 950 ° C. for 1 hour.
(5) Comparative example 5
The oxide powder material p4 was used. Ethyl cellulose was used in an amount of 5 parts by mass based on 100 parts by mass of the oxide powder material. The electrode of Comparative Example 5 was obtained by forming on both surfaces of the CGO 90/10 sintered pellet by screen printing with a mesh for 3 μm and firing at 950 ° C. for 1 hour.
(6) Comparative example 6
The oxide powder material p9 was used. Ethyl cellulose was used in an amount of 8 parts by mass based on 100 parts by mass of the oxide powder material. The electrode of Comparative Example 6 was obtained by forming on both surfaces of a CGO 90/10 sintered pellet by screen printing using a mesh for 20 μm and firing at 950 ° C. for 1 hour.
(7) Comparative example 7
An oxide powder material in which the oxide powder material p10 and CGO 90/10 were mixed at a mass ratio of 50:50 was used. Ethyl cellulose was adjusted to 8 parts by mass with respect to 100 parts by mass of the mixed oxide powder material. An electrode of Comparative Example 7 was obtained by forming both surfaces on a CGO 90/10 sintered pellet by screen printing using a mesh for 20 μm, followed by firing at 950 ° C. for 1 hour.
(8) Comparative Example 8
The oxide powder material p4 was used. Ethyl cellulose was used in an amount of 3 parts by mass based on 100 parts by mass of the oxide powder material. An electrode of Comparative Example 8 was obtained by forming on both surfaces of the CGO 90/10 sintered pellet by screen printing using a mesh for 3 μm and firing at 950 ° C. for 1 hour.
(9) Comparative Example 9
The oxide powder material p4 was used. Ethyl cellulose was used in an amount of 5 parts by mass based on 100 parts by mass of the oxide powder material. An electrode of Comparative Example 9 was obtained by forming both surfaces on the CGO 90/10 sintered pellet by screen printing with a mesh for 10 μm and then firing at 950 ° C. for 1 hour.
(10) Comparative Example 10
The oxide powder material p4 was used. Ethyl cellulose was used in an amount of 10 parts by mass based on 100 parts by mass of the oxide powder material. An electrode of Comparative Example 10 was obtained by forming both surfaces on the CGO 90/10 sintered pellets by screen printing using a mesh for 40 μm, followed by firing at 950 ° C. for 1 hour.
<Measurement of average particle diameter of primary particles>

The average particle diameter of the primary particles of the electrodes of Examples 1 to 12 and Comparative Examples 1 to 10 was determined by the peak half width of X-ray diffraction (eg, SmartLab, manufactured by Rigaku) and the Scherrer equation (Scherrer constant: 0.9). I asked. Table 1 shows the results.
<Measurement of electrode thickness>
The film thicknesses of the electrodes of Examples 1 to 12 and Comparative Examples 1 to 10 were determined by observing the cross sections of the electrodes with a scanning electron microscope (SEM, JSM-5600, manufactured by JEOL Ltd.). Table 1 shows the results. Further, as an example, FIG. 4 shows an SEM image of the electrode portion of the third embodiment.
<Measurement of porosity of electrode>
The electrode cross sections of Examples 1 to 12 and Comparative Examples 1 to 10 were smoothed with a cross section polisher (eg, Ar ion beam, IB-09020CP, manufactured by JEOL), and then SEM (JSM-5600, manufactured by JEOL) ), And the porosity of the electrode was obtained by image processing of the contrast of the SEM image. Table 1 shows the results. Further, as an example, FIG. 5 shows an image processing result of the third embodiment.

<Evaluation of electrode performance>
For the electrodes of Examples 1 to 12 and Comparative Examples 1 to 10, the electrode resistance per unit area at 700 ° C. in an air atmosphere was measured by an AC impedance method (1287, 1255B, manufactured by Solartron). Table 1 shows the results. Note that the electrode resistance is a Cole-Cole plot of the cell to be measured obtained by the AC impedance method, that is, the real part resistance Z ′ (Ω) and the imaginary part resistance Z for each frequency when the frequency is changed. In a graph obtained by plotting “(Ω) as the real part resistance value Z ′ on the horizontal axis and the imaginary part resistance value Z” on the vertical axis, the real part resistance value of two intercepts with the horizontal axis of the graph is obtained. Is the difference.

に お い て In Table 1, SSC and GSC of the electron conductive materials are materials generally used in a temperature range around 700 ° C. Further, LSCF, which is an electron conductive material, is a material which is inferior to SSC and GSC in electrode activity but can be used in a temperature range around 700 ° C. On the other hand, LSM as an electron conductive material is generally used in a relatively high temperature range of 800 ° C. or higher. Therefore, here, the comparisons in Examples 1 to 7 and Examples 11 and 12 using SSC and GSC, Comparative Examples 1 to 5 and Comparative Examples 8 to 10, and Examples 9 and 10 using LSCF, The comparison with Example 7 and the comparison between Example 8 using LSM and Comparative Example 6 will be described separately.

When SSC, GSC, and LSCF were used as the electron conductive materials, Examples 1 to 7 and Examples 9 to 10 exhibited lower electrode resistances than Comparative Examples 1 to 5 and Comparative Examples 7 to 10. This means that the mass ratio of the electron conductive material to the ion conductive material, the average particle diameter of the primary particles in each material of the electron conductive material and the ion conductive material, the thickness of the electrode, and the porosity of the electrode in a specific range. By setting the inside, the reaction resistance reduction effect by expanding the reaction field in the electrode and the gas diffusion resistance reduction effect by good gas diffusivity can be obtained at the same time, and a low electrode resistance is realized. .

Example 8 showed a lower electrode resistance than Comparative Example 6 when LSM was used as the electron conductive material. This means that the mass ratio of the electron conductive material to the ion conductive material, the average particle diameter of the primary particles in each material of the electron conductive material and the ion conductive material, the thickness of the electrode, and the porosity of the electrode in a specific range. By setting the inside, the reaction resistance reduction effect by expanding the reaction field in the electrode and the gas diffusion resistance reduction effect by good gas diffusivity can be obtained at the same time, and a low electrode resistance is realized. .

According to the present invention, it is possible to produce a solid oxide cell electrode and a solid oxide cell having excellent performance with low electrode resistance.

DESCRIPTION OF SYMBOLS 1 Porous electrode 2 Electrolyte 3 Electron conductive material 4 Ion conductive material 5 Intermediate layer 6 Porous electrode 7 Porous electrode 8 Support

Claims (9)

1. An electrode for a solid oxide cell, comprising an electron conductive material and an ion conductive material, wherein the mass ratio of the electron conductive material to the ion conductive material is 75:25 to 25:75,
   The average particle size of the primary particles in each of the electron conductive material and the ion conductive material is 1 nm to 1 μm;
   The electrode has a thickness of 0.5 μm to 50 μm,
   An electrode for a solid oxide cell, wherein the porosity of the electrode is 1 to 30% by volume.
2. 2. The solid oxide cell according to claim 1, wherein the porosity of the electrode is 1 to 15% by volume when the thickness is 0.5 μm ≦ the thickness of the electrode ≦ 1 μm. Electrodes.
3. 2. The electrode for a solid oxide cell according to claim 1, wherein when the film thickness is 1 μm <the film thickness of the electrode ≦ 5 μm, the porosity of the electrode is 5 to 20% by volume. .
4. 2. The electrode for a solid oxide cell according to claim 1, wherein the porosity of the electrode is 7 to 25% by volume when the thickness is 5 μm <the thickness of the electrode ≦ 25 μm. .
5. 2. The solid oxide cell electrode according to claim 1, wherein the porosity of the electrode is 10 to 30% by volume when the thickness is 25 μm <the thickness of the electrode ≦ 50 μm. .
6. 6. A stacked structure, wherein the solid oxide cell electrode according to any one of claims 1 to 5 is formed on an electrolyte or an ion conductive material intermediate layer formed on the electrolyte. Laminated structure.
7. A laminated structure, wherein a porous layer having a higher porosity than the solid oxide cell electrode is laminated on the solid oxide cell electrode of the laminated structure according to claim 6. Characteristic laminated structure.
8. A solid oxide cell comprising an electrolyte, an air electrode and a fuel electrode sandwiching the electrolyte, and having the laminated structure according to claim 6 or 7 on the air electrode side. Oxide type cell.
9. A solid oxide cell comprising an electrolyte, an air electrode and a fuel electrode sandwiching the electrolyte, and having the laminated structure according to claim 6 or 7 on the fuel electrode side. Oxide type cell.

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