JP2004292246A - Ceramic material and solid oxide fuel cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic material, i.e. a titanium oxide which is chemically stable at an elevated temperature in an oxidative/reductive atmosphere and is excellent in sinterability through a manufacturing method without a CIP molding step, and a solid oxide fuel cell wherein the titanium oxide is installed as an interconnector membrane. <P>SOLUTION: The ceramic material has a composition represented by formula 1: ATi<SB>1-y</SB>V<SB>y</SB>O<SB>3</SB>(wherein A is at least one element chosen from Mg, Ca, Sr and Ba; 0<y≤0.3) or formula 2: A<SB>1-x</SB>B<SB>x</SB>Ti<SB>1-y</SB>V<SB>y</SB>O<SB>3</SB>(wherein A is at least one element chosen from Mg, Ca, Sr and Ba; B is a lanthanoid element chosen from La, Nd and the like; 0<x≤0.3; and 0<y≤0.3). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ceramic material having excellent sinterability. In particular, it relates to a ceramic material suitable as an interconnector film for a solid oxide fuel cell.
[0002]
[Prior art]
Conventionally, as a material of an interconnector film in a solid oxide fuel cell, a composition formula 3: LaCrO ₃ is used as a base material because it is chemically stable in both oxidation and reduction atmospheres and has excellent electron conductivity. A ceramic material (hereinafter referred to as chromium oxide) has been proposed (for example, see Patent Document 1). Here, the parent substance refers to an original substance in which another element or the like is not added to a certain element position of the substance.
Further, the solid oxide fuel cell can be sintered at a temperature of about 1400 ° C. for sintering materials such as an air electrode and an electrolyte. Ceramic material having a material represented by the composition formula 4: MTiO ₃ (M is generally an alkaline earth metal element) as a base material (hereinafter referred to as a titanium oxide) Has been proposed as a candidate for a material of an interconnector membrane in a solid oxide fuel cell (for example, see Patent Document 2).
[0003]
[Patent Document 1]
JP-A-9-249419 (pages 1-7)
[Patent Document 4]
JP-A-11-54137 (pages 1-20)
[0004]
[Problems to be solved by the invention]
In the case of manufacturing a solid oxide fuel cell by a sintering method, a ceramic material having the composition formula 3 as a base material as disclosed in Patent Literature 1 is used in combination with other members of a solid oxide fuel cell such as zirconia. There is a problem that it is difficult to perform firing at the same time. For this reason, in order to fire simultaneously with the other members, the development of a material that can be sintered at a temperature of about 1400 ° C. has been a problem.
[0005]
In the case of a material such as the composition formula 4 shown in Patent Document 2, a dense body is formed at a firing temperature of about 1400 ° C. through a high pressure forming step of about 1 to 5 t / cm ² by CIP (Cold Isostatic Pressing) or the like. Although it is reported that the above process can be obtained, the above process is inferior in productivity and causes a cost increase. Therefore, it was necessary to obtain a dense body without passing through the previous process.
[0006]
The present invention has been made in order to solve the above-mentioned problems. In a high-temperature state, a titanium oxide which is chemically stable in an oxidizing / reducing atmosphere and which can be sintered without a CIP molding step. It is another object of the present invention to provide a titanium oxide suitable as an interconnector membrane for a solid oxide fuel cell operating under the above conditions.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a first invention is to provide a composition formula 1: ATi _1-y V _y O ₃ (A is one or more elements of Mg, Ca, Sr, and Ba, and 0 <y ≦ 0.3), or the composition formula _{2: a 1-x B x} Ti 1-y V y O 3 (a is Mg, Ca, Sr, or one or more elements of Ba, B is La, Provided is a ceramic material represented by a lanthanoid element such as Nd, 0 <x ≦ 0.3, 0 <y ≦ 0.3).
[0008]
According to the present invention, a ceramic material represented by the composition formula, formula 5: ATiO ₃ or formula _{6: A 1-x B x} TiO 3 (A and B, the same as the a) is represented by Vanadium (element symbol: V) is added to a Ti site of a ceramic material, and the addition of the vanadium makes it possible to provide a ceramic material having excellent sinterability.
The reason for the invention is that when vanadium is added to titanium oxide, as represented by the above composition formula 1 or 2, the physical and chemical mechanism is not yet well understood, but the effect of improving sinterability is improved. Because there is.
The reason why the addition amounts x and y of the element B and vanadium are limited is that, when the addition amount x of the element B becomes 0.3 or more, an impurity phase (pyrochlore component) is generated crystallinely. preferable. When y is 0.2 or more, the effect of the porosity on y is saturated when y is 0.2 or more, and when y> 0.3, the chemical stability at high temperature and under both redox atmosphere is reduced. It is because it decreases.
[0009]
The second invention provides a solid oxide fuel cell in which the ceramic material represented by the composition formula 1 or 2 is used for an interconnect membrane of a solid oxide fuel cell.
According to the present invention, since the ceramic material represented by the composition formula 1 or 2 is used for an interconnector film of a solid oxide fuel cell, an interconnector film having good denseness, which is a required characteristic of the interconnector film, is provided. It is possible to provide an improved solid oxide fuel cell.
The reason for the effect of the invention is that, as represented by composition formula 1 or 2, vanadium having a function of improving sinterability is dissolved in titanium oxide.
[0010]
A third invention is an interconnector membrane of a solid oxide fuel cell using the ceramic material represented by the composition formula 2, wherein x is in the range of 0.05 ≦ x ≦ 0.2, And y is in the range of 0.005 ≦ y ≦ 0.1.
According to the present invention, by limiting the x and y in the composition formula 2 within the above range, the required properties of the interconnector film, such as denseness and electron conductivity, become better values. It is possible to provide a solid oxide fuel cell.
The reason for the effect of the invention is that when x is 0.05 or more, the electronic conductivity of the ceramic material used is good, so that the performance of the solid oxide fuel cell used as the interconnector membrane is reduced. When x is 0.2 or less, the value of the gas permeation flow rate (which will be described later) indicating the degree of denseness becomes a more preferable value. This is because the performance of the solid oxide fuel cell can be improved.
[0011]
When the value of y is 0.005 or more, the sinterability of the ceramic material used is better, the gas permeation flow velocity is small, and the density is high. Although the performance of the fuel cell can be improved, when y is larger than 0.1, the gas permeation flow rate becomes a slightly larger value. Therefore, when y is in the range of 0.005 ≦ y ≦ 0.1, an interconnector membrane having better characteristics is used, so that a solid oxide fuel cell having better performance can be provided. .
[0012]
Here, "dense" refers to a state having a small value of "gas permeation flow rate", and the "gas permeation flow rate" refers to the amount of gas leaking from one side to the opposite side of the membrane, It is used to evaluate the degree of shielding (hereinafter referred to as “density”).
[0013]
In the evaluation of the compactness of the membrane, the value of the gas permeation flow rate Q is used, which is given by
Q = D / S / P [m / s / Pa] (1)
(However, D: transmission amount, S: transmission area, P: applied pressure)
As the density required for cells of solid oxide fuel cells,
Q <2.8 × 10 ⁻⁹ (m / s / Pa) (2)
It is preferable that More preferably,
Q <2.8 × 10 ⁻¹⁰ (m / s / Pa) (3)
It is.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below by taking an interconnector membrane of a solid oxide fuel cell as an example.
[0015]
First, an outline of a solid oxide fuel cell according to the present invention and members constituting the solid oxide fuel cell will be described below with reference to FIG.
FIG. 1 is a schematic diagram showing a cross section of a cylindrical solid oxide fuel cell (hereinafter abbreviated as a cell). A strip-shaped interconnector membrane 2 and an electrolyte membrane 3 are provided on a cylindrical porous air electrode support 1, and a fuel electrode membrane 4 is formed on the electrolyte membrane 3 so as not to contact the interconnector membrane 2. Have been. In a solid oxide fuel cell, at a high temperature of about 500 to 1000 ° C., the inside of the cathode support 1 has an oxidizing atmosphere in which air is introduced, and the outside of the cell has a reducing atmosphere in which a fuel gas such as hydrogen or methane is introduced. As a result, an electromotive force is generated between the air electrode and the fuel electrode sandwiching the electrolyte, and it becomes possible to extract electricity to the outside by connecting the interconnector film 2 and the fuel electrode film 4.
[0016]
As described above, the following materials are generally used depending on conditions such as the operating environment of the solid oxide fuel cell and the chemical reaction between members.
Since the cathode support 1 is required to be chemically stable and have electronic conductivity in a high-temperature oxidizing atmosphere, the composition formula 7: La _1-x A ^* _x MnO ₃ (A ^* : Sr, Examples of the material include Ca) as a base substance. The electrolyte membrane 3 may be made of a material that is required to be chemically stable under both high-temperature oxidation and reduction atmospheres and to have oxygen ion conductivity, such as zirconia to which a rare earth element such as yttrium or scandium is added. it can. The fuel electrode film 4 includes a cermet material having a high electron conductivity in which nickel metal and zirconia are mixed. Here, the zirconia is preferably zirconia to which a rare earth element or the like has been added as in the case of the electrolyte membrane material. The interconnector film 2 uses the titanium oxide of the present invention. The details will be described below.
[0017]
Interconnector membranes for solid oxide fuel cells have the following major characteristics: chemical stability at high temperatures and redox atmospheres, gas shielding (density), high electron conductivity, and thermal expansion coefficient. Almost coincides with other members such as an electrolyte. In particular,
Denseness: Q <2.8 × 10 ⁻⁹ (m / s / Pa)
(More preferably, Q <2.8 × 10 ⁻¹⁰ (m / s / Pa))
Electronic conductivity: σ _e ≧ 1 (S / cm)
Materials satisfying the target values as described above include chromium oxide and titanium oxide.
[0018]
The denseness of the interconnector film depends on the sinterability of the material. The better the sinterability of the material, the more likely it is to be dense. However, if the sintering property is excessively improved, the interconnector film may be reduced in density due to generation of small holes on its surface. Is not always the case.
[0019]
The thickness is preferably in the range of about 10 to 100 μm. If it is less than 10 μm, it is technically difficult to produce a dense film, and if it is more than 100 μm, the internal resistance increases.
[0020]
It is preferable to provide a dense film between the air electrode and the interconnector film. The reason is that the titanium oxide has a somewhat low electron conductivity in an oxidizing atmosphere. Therefore, a dense film using a material having high electron conductivity in an oxidizing atmosphere such as the composition formula 7 is provided between the titanium oxide and the air electrode. This makes it possible to lower the internal resistance.
[0021]
【Example】
The contents of the tests performed to confirm the effects of the present invention are shown below.
[0022]
[Example 1: Evaluation by prismatic bulk body, A: Sr]
In preparing a material represented by a composition formula 8: SrTi _1-y V _y O ₃ and a composition formula 9: Sr _1- xB _x Ti _1-y V _y O ₃ (B is La and Nd), As raw materials, titanium oxide (TiO ₂ ), vanadium oxide (V ₂ O ₅ ), and strontium carbonate (SrCO ₃ ) are used as raw materials for the lanthanoid element (B), and lanthanum oxide (La ₂ O ₃ ) and neodymium oxide (Nd ₂ O ₃ ) was used.
The raw materials are weighed so as to obtain a target composition, mixed in a wet ball mill using ethanol as a solvent for 24 hours, heated to 60 ° C., dried, and put in a hard bowl made of alumina at a temperature of 1200 ° C. Calcination was performed for 5 hours. Thereafter, the same ball mill mixing and drying were performed again to prepare a raw material powder. The molding was performed by uniaxial pressure molding at a pressure of 200 kg / cm ² into a prism having a cross-sectional area of 2.5 × 10 ⁻⁵ m ² and a length of about 4.0 × 10 ⁻² m at a temperature of 1400 ° C. The firing was performed for a holding time of 10 hours. The sample obtained by this method was evaluated, and the porosity was calculated by the Archimedes method.
[0023]
The porosity K is a volume ratio of pores contained in the sample,
K = (W3-W1) / (W3-W2) × 100 [%] (4)
Calculated as W1: dry weight W2: underwater weight W3: saturated water weight. Generally, the smaller the value is, the better the sinterability is evaluated. Generally, if the porosity is less than 3%, it is evaluated as sufficiently dense, and it is more preferable that the porosity is less than 1%.
[0024]
Figure 2 the composition formula _9: in samples represented by _{Sr 1-x B x Ti 1} -y V y O 3, shows the data of the porosity of the material using La and Nd to B element. In all ranges of 0 ≦ x ≦ 0.3 in the La added amount x, it was confirmed that the porosity was reduced to half or less by the addition of vanadium, and it became a material excellent in sinterability. confirmed.
[0025]
In this embodiment, La and Nd are used as the B element. However, since similar characteristics are obtained, similar results are obtained even when other lanthanoid elements such as Pr and Sm are used. I can say.
[0026]
From the above implementation results, formula _{8: SrTi 1-y V y} O 3 (0 <y ≦ 0.3) and formula _{9: Sr 1-x B x} Ti 1-y V y O 3 (B is La It has been found that the use of a lanthanoid element such as N or Nd and ceramic materials represented by 0 <x ≦ 0.3, 0 <y ≦ 0.3) results in a material having excellent sinterability.
[0027]
[Example 2: Evaluation by prismatic bulk material, A: Ca]
Composition formula 10: In producing Ca _1-x La _x Ti _1-y V _y O ₃ , titanium oxide (TiO ₂ ), vanadium oxide (V ₂ O ₅ ), calcium carbonate (CaCO ₃ ), Using lanthanum oxide (La ₂ O ₃ ), a sample was prepared and evaluated in the same manner as in Example 1.
[0028]
FIG. 3 shows porosity data of a sample represented by composition formula 10: Ca _1-x La _x Ti _1-y V _y O ₃ . In the same manner as in Example 1, it was confirmed that the porosity was reduced by more than half by the addition of vanadium (0 <y ≦ 0.3). 0.3, 0 <y ≦ 0.3), it was confirmed that the ceramic material was excellent in sinterability.
[0029]
Generally, in the titanium oxide according to the present invention, vanadium is replaced by a Ti site as in the compositional formula 2: A _1-x B _x Ti _1-y V _y O ₃ , so that the element types of the A element and the B element are used. Alternatively, the degree of sinterability varies depending on the amount of addition, but it is apparent that it does not particularly contribute to the effect of excellent sinterability. As a confirmation, in the results of Examples 1 and 2, Sr and Ca were used as the A element, and La and Nd were used as the B element, and almost the same sinterability was exhibited. Therefore, in the first invention of the present invention, a system in which the element A is mixed with another alkaline earth element such as Mg or Ba, the A site is mixed with two or more alkaline earth metal elements, and the B element is Pr , Lanthanide elements other than La and Nd such as Sm and Gd.
[0030]
In addition, in the addition test of the element B using La and Nd, in particular, the result that the porosity was almost the same was obtained. Therefore, the element B element also affected the degree of sinterability due to the addition of vanadium. I can say nothing. Therefore, also in the third invention of the present invention, the B element may be other lanthanoid elements other than La such as Pr, Nd, Sm.
[0031]
[Example 3: Evaluation of interconnector film, A: Sr]
Hereinafter, the second invention of the present invention relates to the production of an interconnector membrane for a solid oxide fuel cell using a ceramic material represented by composition formula 11: Sr _1-x La _x Ti _1-y V _y O _3. And the contents of the evaluation.
[0032]
Hereinafter, description will be given along the process of forming an interconnector of a solid oxide fuel cell.
As for the preparation of the cell, the air electrode made of the composition formula 12: La _0.80 Sr _0.20 MnO ₃ (hereinafter referred to as LSM) is extruded into a cylindrical shape, baked, and then the interconnector is formed into a part. An electrolyte made of yttria-stabilized zirconia (hereinafter, referred to as YSZ) is formed on the outside of the cylinder except for, and a cermet fuel electrode formed by mixing nickel oxide (NiO) and YSZ is formed on the electrolyte. Thereafter, a film of an interconnector is formed.
[0033]
The film forming process of the interconnector is as follows.
As raw materials, titanium oxide (TiO ₂ ), vanadium oxide (V ₂ O ₅ ), strontium carbonate (SrCO ₃ ), calcium carbonate (CaCO ₃ ), and lanthanum oxide (La ₂ O ₃ ) are prepared, each having a desired composition. The mixture was weighed and mixed in a ball mill. Then, after calcining under conditions of a temperature of 1200 ° C. and a holding time of 5 hours, and then pulverized, 1.0 kg of the obtained powder, 4.5 kg of ethanol, and 1.8 × 10 ⁻¹ kg of a binder (ethyl cellulose) were obtained. And 3.0 × 10 ⁻² kg of a dispersant (polyoxyetalene alkylsonate) were mixed by ball mixing. The slurry obtained by mixing is placed in a sealed cylindrical container on one side.
The masked cell is dipped into the container except for the portion where the interconnector is to be formed in advance, and is held for several seconds and then pulled up. Thereafter, drying was performed in an atmosphere at 60 ° C., and dipping and drying were repeated until a predetermined film thickness was obtained. Thereafter, baking was performed at a temperature of 1400 ° C. and a holding time of 5 hours. The number of dips was adjusted so that the thickness (film thickness) of the interconnector film after firing was adjusted to about 50 μm. Thereafter, an epoxy-based resin was applied to portions other than the interconnector film to prevent gas from passing at all.
[0034]
As an evaluation of the denseness of the cell, nitrogen gas was flowed from inside the cell, a pressure of 1.0 × 10 ⁵ Pa was applied, and the gas permeation flow rate Q of the interconnector membrane was measured. The results are shown below.
[0035]
FIG. 4 shows the relationship between the amount of vanadium added and the gas permeation flow rate Q. From this, it was confirmed that the gas permeation flow rate Q was less than the target 2.8 × 10 ⁻⁹ (m / s / Pa) in the range of 0.005 ≦ y ≦ 0.3, and a dense film was obtained. did. Further, in the range of 0.005 ≦ y ≦ 0.1, the gas permeation flow rate Q becomes less than the more preferable value of 2.8 × 10 ⁻¹⁰ (m / s / Pa), and a film more preferable in denseness is obtained. I confirmed that. In a range other than the above in y, a result below the target value was not obtained, and a dense film was not obtained.
[0036]
FIG. 5 shows the relationship between the amount of La added and the gas permeation flow rate Q. From this, it was confirmed that the gas permeation flow rate Q was less than the target of 2.8 × 10 ⁻⁹ (m / s / Pa) in the range of 0.05 ≦ x ≦ 0.3, and a dense film was obtained. did. Further, it was confirmed that the gas permeation flow rate Q was less than the target of 2.8 × 10 ⁻¹⁰ (m / s / Pa) in the range of 0.05 ≦ x ≦ 0.2, and a dense film was obtained. . In a range other than the above in x, a result below the target value was not obtained, and a dense film was not obtained.
[0037]
[Example 4: Evaluation of electron conductivity, A: Sr]
The measurement of the electron conductivity under a reducing atmosphere was performed by the four-terminal method using the prismatic bulk material described in Example 1 above. The prismatic bulk body was manufactured in the same manner as in Example 1, and then four terminals were attached using a nickel wire and a nickel paste. The sample was placed in an electric furnace, and the electron conductivity was measured at 1000 ° C. in hydrogen.
[0038]
FIG. 6 shows the relationship between the amount of vanadium added and the electron conductivity at 1000 ° C. in a reducing atmosphere. From this, when the La addition amount x is less than 0.05, the electron conductivity is inferior. Therefore, the La addition amount x is preferably 0.05 or more.
[0039]
From the above results, the interconnector film using the ceramic material represented by the composition formula 11: Sr _1-x La _x Ti _1-y V _y O ₃ has a value of 0.05 ≦ x ≦ 0.2, 0.005 It was confirmed that it was more preferable that the range was ≦ y ≦ 0.1.
[0040]
[Example 5: Evaluation of interconnector film, A: Ca]
Hereinafter, the second invention of the present invention relates to the production of an interconnector membrane for a solid oxide fuel cell using a ceramic material represented by composition formula 10: Ca _1-x La _x Ti _1-y V _y O _3. And the contents of the evaluation.
[0041]
Preparation of the solid oxide fuel cell is the same as in the third embodiment. The process of forming the interconnector film is almost the same as that of the third embodiment. However, as raw materials, titanium oxide (TiO ₂ ), vanadium oxide (V ₂ O ₅ ), calcium carbonate (CaCO ₃ ), and lanthanum oxide (La ₂ O ₃ ) is used.
[0042]
FIG. 7 shows the relationship between the amount of vanadium added and the gas permeation flow rate Q. From this, it was confirmed that the gas permeation flow rate Q was less than the target 2.8 × 10 ⁻⁹ (m / s / Pa) in the range of 0.005 ≦ y ≦ 0.3, and a dense film was obtained. did. Further, in the range of 0.005 ≦ y ≦ 0.1, the gas permeation flow rate Q becomes less than the more preferable value of 2.8 × 10 ⁻¹⁰ (m / s / Pa), and a film more preferable in denseness is obtained. I confirmed that. In a range other than the above in y, a result below the target value was not obtained, and a dense film was not obtained.
[0043]
FIG. 8 shows the relationship between the amount of La added and the gas permeation flow rate Q. From this, it was confirmed that the gas permeation flow rate Q was less than the target 2.8 × 10 ⁻⁹ (m / s / Pa) in the range of 0 ≦ x ≦ 0.3, and a dense film was obtained. Further, in the range of 0.05 ≦ x ≦ 0.2, the gas permeation flow rate Q is less than the more preferable value of 2.8 × 10 ⁻¹⁰ (m / s / Pa), and a film more preferable in denseness is obtained. I confirmed that. In a range other than the above in x, a result below the target value was not obtained, and a dense film was not obtained.
[0044]
[Example 6: Evaluation of electron conductivity, A: Ca]
The measurement of the electron conductivity in a reducing atmosphere was performed by the four-terminal method using the prismatic bulk material described in Example 2. The preparation and measurement of the sample are the same as in Example 4.
[0045]
FIG. 9 shows the relationship between the amount of vanadium added and the electron conductivity at 1000 ° C. in a reducing atmosphere. From this, when the La addition amount x is less than 0.05, the electron conductivity is inferior. Therefore, the La addition amount x is preferably 0.05 or more.
[0046]
From the above results, the interconnector film using the ceramic material represented by the composition formula 10: Ca _1-x La _x Ti _1-y V _y O ₃ has a value of 0.05 ≦ x ≦ 0.2, 0.005 It was confirmed that it was more preferable that the range was ≦ y ≦ 0.1.
[0047]
【The invention's effect】
Composition formula 1: ATi _1-y V _y O ₃ (A is one or more of Mg, Ca, Sr, and Ba, 0 <y ≦ 0.3), or composition formula 2: A _{1− x B x Ti 1-y V} y O 3 (a is Mg, Ca, Sr, or one or more elements of Ba, B is La, lanthanoid elements such as Nd, 0 <x ≦ 0.3, Since 0 <y ≦ 0.3) is proposed, a ceramic material having excellent sinterability can be provided. Further, the present invention provides a solid oxide fuel cell provided with an interconnector film having excellent denseness and electronic conductivity.
[Brief description of the drawings]
FIG. 1 is a schematic view of a solid oxide fuel cell showing an embodiment of the present invention.
FIG. 2 shows composition formula 8: SrTi _1-y V _y O ₃ (provided that x = 0 in composition formula 9) and composition formula 9: Sr _1-x B _x Ti in Example 1 of the present invention. is a diagram illustrating a _1-y V _y O ₃ using La and Nd in element B in the sample represented by the material of vanadium addition amount y and the porosity of the relationship.
FIG. 3 is a diagram showing a relationship between a vanadium addition amount y and a porosity in a sample represented by a composition formula 10: Ca _1-x La _x Ti _1-y V _y O ₃ in Example 2 of the present invention. .
FIG. 4 is a diagram showing a relationship between a vanadium addition amount y and a gas permeation flow rate Q in a sample represented by a composition formula 11: Sr _1-x La _x Ti _1-y V _y O ₃ in Example 3 of the present invention. It is.
FIG. 5 shows the relationship between the amount x of La added and the gas permeation flow rate Q in a sample represented by composition formula 11: Sr _1-x La _x Ti _1-y V _y O ₃ in Example 3 of the present invention. FIG.
FIG. 6 shows the amount of vanadium added in a sample represented by composition formula 11: Sr _1-x La _x Ti _1-y V _y O ₃ and electron conduction at 1000 ° C. under a reducing atmosphere in Example 4 of the present invention. It is a figure showing the relationship with a rate.
FIG. 7 shows the relationship between the amount y of vanadium added and the gas permeation flow rate Q in a sample represented by composition formula 10: Ca _1-x La _x Ti _1-y V _y O ₃ in Example 5 of the present invention. FIG.
FIG. 8 shows the relationship between the La addition amount x and the gas permeation flow rate Q in a sample represented by composition formula 10: Ca _1−x La _x Ti _1−y V _y O ₃ in Example 5 of the present invention. FIG.
FIG. 9 shows the amount of vanadium added in a sample represented by composition formula 10: Ca _1−x La _x Ti _1−y V _y O ₃ and electron conduction at 1000 ° C. under a reducing atmosphere in Example 6 of the present invention. Indicates the relationship with the rate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Air electrode support 2 ... Interconnector membrane 3 ... Electrolyte membrane 4 ... Fuel electrode membrane

Claims (3)

Composition formula 1: ATi _1-y V _y O ₃ (A is one or more of Mg, Ca, Sr, and Ba, 0 <y ≦ 0.3), or composition formula 2: A _{1− x B x Ti 1-y V} y O 3 (a is Mg, Ca, Sr, or one or more elements of Ba, B is La, lanthanoid elements such as Nd, 0 <x ≦ 0.3, 0 <y ≦ 0.3) A ceramic material represented by the formula: A solid oxide fuel cell wherein the ceramic material represented by the composition formula 1 or 2 is used for an interconnector film of a solid oxide fuel cell. The interconnector film, formula _{2: A 1-x B x} Ti 1-y V y O 3 (A is Ca, comprises either one or both elements of Sr, B is La, lanthanoid elements such as Nd, 3. The solid oxide fuel cell according to claim 2, wherein the solid oxide fuel cell is made of a ceramic material represented by 0.05 ≦ x ≦ 0.2 and 0.005 ≦ y ≦ 0.1).

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