Air electrode material for proton conduction ceramic fuel cell, air electrode for proton conduction ceramic fuel cell and proton conduction ceramic fuel cell

Abstract

To provide an air electrode material and an air electrode for a proton conduction ceramic fuel cell, having low reaction resistance of an air electrode and capable of achieving high output density, and a proton conduction ceramic fuel cell using the air electrode.SOLUTION: An air electrode for a proton conduction ceramic fuel cell is a perovskite-type composite oxide represented by the following general formula (1): Bax1Coα1Feβ1Mgγ1Mδ1O3-y1 (1) (in formula (1), M represents at least one selected from among Ti, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc and Ga, x1 is 0.90 to 1.10, α1 exceeds 0.00 and 1.00 or less, β1 exceeds 0.00 and 1.00 or less, γ1 exceeds 0.00 and 0.30 or less, δ1 exceeds 0.00 and 0.30 or less, and y1 is 0.0 or more and 0.8 or less).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an air electrode material used in the manufacture of a proton-conducting ceramic fuel cell, and to an air electrode for a proton-conducting ceramic fuel cell and a proton-conducting ceramic fuel cell using the same. [Background technology]

[0002] Solid oxide cells for electrochemical reactions are devices that enable highly efficient energy conversion, and research and development toward their practical application is underway by ceramic manufacturers, the energy industry, the automotive industry, etc. For example, they are used in devices such as fuel cell systems, electrolysis systems, and hydrogen compressors.

[0003] Typical examples of devices using solid oxide cells include solid oxide fuel cells and solid oxide electrolysis cells. A solid oxide cell is composed of a dense electrolyte, primarily made of oxide, sandwiched between two porous electrodes: an air electrode and a fuel electrode. Depending on the constituent materials, a wide operating temperature range can be selected for this solid oxide cell, and it can be used in the range of 400 to 1000°C.

[0004] The electrode material is an electron-conductive oxide or metal with catalytic activity (hereinafter referred to as "electron-conductive material"). Although electron-conductive materials may be used alone, they may also be mixed with an ion-conductive material that conducts the same ions as the electrolyte or the same ions as the electrolyte ("ions" refers to all ions that act as conductive carriers, including oxide ions and protons), in order to expand the reaction field within the electrode. In general, the reaction resistance of the electrode is reduced by mixing an electron-conductive material with an ion-conductive material. The reaction resistance depends on the size of the reaction field (or the number of reaction active sites) per unit area of ​​the electrode and the activity per reaction field.

[0005] In solid oxide fuel cells, the charge carrier ions are mainly oxide ions and protons. Among solid oxide cells, those in which the charge carrier ions are mainly protons are called proton-conducting ceramic cells. In proton-conducting ceramic cells, the material that conducts protons is called a proton-conducting electrolyte. Typical examples of proton-conducting electrolytes include perovskite-type oxide materials.

[0006] Compared to oxide-ion conducting ceramic cells, proton conducting ceramic fuel cells have the advantage of being able to increase fuel utilization rate because water vapor is not generated at the anode when used in fuel cells, and when used as an electrolysis cell, hydrogen is discharged to the anode side, allowing for a high hydrogen concentration, resulting in higher energy conversion efficiency.Furthermore, because the activation energy of proton conduction is low, proton conducting ceramic fuel cells have the advantage of being able to be used at lower operating temperatures than oxide-ion conducting ceramic fuel cells.

[0007] Research and development of proton-conducting ceramic fuel cells to date has focused on oxides such as (LaSr)MnO3, (LaSr)FeO3, (LaSr)CoO3, and (LaSr)(CoFe)O3 as the cathode material, oxides such as Ba(ZrYb)O3 and Ba(ZrCeYYb)O3 as the electrolyte material, and cermets such as NiO-Ba(ZrYb)O3 as the fuel electrode material.

[0008] For example, Non-Patent Document 1 discloses a proton-conducting ceramic fuel cell that uses a barium-zirconium perovskite-type composite oxide containing Ba in the A site and Zr in the B site as an air electrode material. [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] C. Duan, J. Tong, M. Shang, S. Nikodemski, M. Sanders, S. Ricote, A. Almansoori, RO'Hayre1, “Readily processed protonic ceramic fuel cells with high performance at low temperatures, Science 349 1321-1326 (2015) Summary of the Invention [Problem to be solved by the invention]

[0010] It goes without saying that proton-conducting ceramic fuel cells need to have high output (maximum power density), but the reality is that in current proton-conducting ceramic fuel cells, 60 to 80% of the voltage loss is due to reaction resistance (polarization resistance) at the air electrode.

[0011] Therefore, in the development of proton-conducting ceramic fuel cells, it is important to develop air electrode materials for proton-conducting ceramic fuel cells that can not only increase output (maximum power density) but also reduce the reaction resistance (polarization resistance) of the air electrode.

[0012] However, the barium-zirconium perovskite composite oxide disclosed in Non-Patent Document 1 has limitations in improving the maximum power density and reducing the reaction resistance of the air electrode, and further improvements are required.

[0013] Therefore, an object of the present invention is to provide an air electrode material and an air electrode for a proton-conductive ceramic fuel cell that have a low reaction resistance at the air electrode and can increase the output density, and a proton-conductive ceramic fuel cell using the same. [Means for solving the problem]

[0014] As a result of extensive research to solve the above problems, the inventors discovered that for perovskite-type composite oxides containing Ba at the A site, whereas conventional technology has included Zr at the B site, by not including Zr at the B site but including one or more of Mg, Ti, Ni, and Zn, the reaction resistance of the air electrode can be reduced and the power density can be increased, leading to the development of the present invention.

[0015] That is, the present invention (1) relates to a compound represented by the following general formula (1): Ba x1 Co α1 Fe β1 Mg γ1 M δ1 O 3-y1 (1) (In formula (1), M is at least one of Ti, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x1 is 0.90 to 1.10; α1 is greater than 0.00 and less than or equal to 1.00; β1 is greater than 0.00 and less than or equal to 1.00; γ1 is greater than 0.00 and less than or equal to 0.30; δ1 is greater than 0.00 and less than or equal to 0.30; and y1 is 0.00 to 0.80.) The present invention provides an air electrode material for a proton-conducting ceramic fuel cell, which is a perovskite-type composite oxide represented by the formula:

[0016] The present invention (2) also relates to a compound represented by the following general formula (2): Ba x2 Co α2 Fe β2 Ni γ2 M δ2 O 3-y2 (2) (In formula (2), M is at least one of Mg, Ti, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x2 is 0.90 to 1.10; α2 is greater than 0.00 and less than or equal to 1.00; β2 is greater than 0.00 and less than or equal to 1.00; γ2 is greater than 0.00 and less than or equal to 0.30; δ2 is greater than 0.00 and less than or equal to 0.30; and y2 is 0.00 to 0.80.) The present invention provides an air electrode material for a proton-conducting ceramic fuel cell, which is a perovskite-type composite oxide represented by the formula:

[0017] The present invention (3) also relates to a compound represented by the following general formula (3): Ba x3 Co α3 Fe β3 Zn γ3 M δ3 O 3-y3 (3) (In formula (3), M is at least one of Mg, Ti, Ni, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x3 is 0.90 to 1.10; α3 is greater than 0.00 and less than or equal to 1.00; β3 is greater than 0.00 and less than or equal to 1.00; γ3 is greater than 0.00 and less than or equal to 0.30; δ3 is greater than 0.00 and less than or equal to 0.30; and y3 is 0.00 to 0.80.) The present invention provides an air electrode material for a proton-conducting ceramic fuel cell, which is a perovskite-type composite oxide represented by the formula:

[0018] The present invention (4) also relates to a compound represented by the following general formula (4): Ba x4 Co α4 Fe β4 Ti γ4 M δ4 O 3-y4 (4) (In formula (4), M is at least one of Mg, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x4 is 0.90 to 1.10; α4 is more than 0.00 and not more than 1.00; β4 is more than 0.00 and not more than 1.00; γ4 is more than 0.00 and not more than 0.30; δ4 is more than 0.00 and not more than 0.30; and y4 is 0.00 to 0.80.) The present invention provides an air electrode material for a proton-conducting ceramic fuel cell, which is a perovskite-type composite oxide represented by the formula:

[0019] The present invention (5) also provides an air electrode for a proton-conductive ceramic fuel cell, characterized in that it contains 30.0 mass % or more of the air electrode material for a proton-conductive ceramic fuel cell according to (1).

[0020] The present invention (6) also provides an air electrode for a proton-conductive ceramic fuel cell, characterized in that it contains 30.0 mass % or more of the air electrode material for a proton-conductive ceramic fuel cell according to (2).

[0021] The present invention (7) also provides an air electrode for a proton-conductive ceramic fuel cell, characterized in that it contains 30.0 mass % or more of the air electrode material for a proton-conductive ceramic fuel cell according to (3).

[0022] The present invention (8) also provides an air electrode for a proton-conductive ceramic fuel cell, characterized in that it contains 30.0 mass % or more of the air electrode material for a proton-conductive ceramic fuel cell according to (4).

[0023] The present invention (9) also provides a fuel cell comprising an air electrode, an electrolyte, and an anode formed in this order: air electrode / electrolyte / anode; The air electrode is a proton-conductive ceramic fuel cell air electrode according to any one of (5) to (8), The electrolyte is represented by the following general formula (6): Ba x6 (Zr α6 Ce β6 B6 (1-α6-β6) ) y6 O 3+z6 (6) (In formula (6), B6 ​​is at least one of Sc, Ga, Y, In, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf, x6 is 0.80 to 1.20, α6 is 0.10 to 0.90, β6 is 0.00 to 0.10, y6 is 0.80 to 1.20, and z6 is −0.80 to +0.80.) The perovskite-type proton-conductive oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conductive oxide represented by the formula (I). The present invention provides a proton-conducting ceramic fuel cell characterized by the above.

[0024] The present invention (10) also provides a fuel cell comprising an air electrode, an intermediate layer, an electrolyte, and an anode, which are formed in this order: air electrode / intermediate layer / electrolyte / anode; The air electrode is a proton-conductive ceramic fuel cell air electrode according to any one of (5) to (8), The electrolyte is represented by the following general formula (6): Ba x6 (Zr α6 Ce β6 B6 (1-α6-β6) ) y6 O 3+z6 (6) (In formula (6), B6 ​​is at least one of Sc, Ga, Y, In, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf, x6 is 0.80 to 1.20, α6 is 0.10 to 0.90, β6 is 0.00 to 0.10, y6 is 0.80 to 1.20, and z6 is −0.80 to +0.80.) The perovskite-type proton-conductive oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conductive oxide represented by the formula (I). The intermediate layer is formed of a polymer represented by the following general formula (7): A7 x7 B7 y7 O 3+z7 (7) (In formula (7), A7 is at least one of Ca, Sr, Ba, and La; B7 is at least one of Sc, Ga, Y, Zr, In, Ce, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf; x7 is 0.80 to 1.20; y7 is 0.80 to 1.20; and z7 is −0.80 to +0.80.) The perovskite-type proton-conductive oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conductive oxide represented by the formula (I). The present invention provides a proton-conducting ceramic fuel cell characterized by the above.

[0025] In this specification, when a numerical range is indicated using "to", the numerical values ​​at both ends are included. In other words, "XX to △△" means "greater than or equal to XX and less than or equal to △△". [Effects of the Invention]

[0026] According to the present invention, it is possible to provide an air electrode material and an air electrode for a proton-conductive ceramic fuel cell that have a low reaction resistance at the air electrode and can increase the power density, as well as a proton-conductive ceramic fuel cell using the same. DETAILED DESCRIPTION OF THE INVENTION

[0027] The first aspect of the present invention provides a proton-conducting ceramic fuel cell air electrode material represented by the following general formula (1): Ba x1 Co α1 Fe β1 Mg γ1 M δ1 O 3-y1 (1) (In formula (1), M is at least one of Ti, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x1 is 0.90 to 1.10; α1 is greater than 0.00 and less than or equal to 1.00; β1 is greater than 0.00 and less than or equal to 1.00; γ1 is greater than 0.00 and less than or equal to 0.30; δ1 is greater than 0.00 and less than or equal to 0.30; and y1 is 0.00 to 0.80.) The air electrode material for proton-conducting ceramic fuel cells is characterized by being a perovskite-type composite oxide represented by the following general formula (1): The perovskite-type composite oxide represented by the general formula (1) is either an oxide ion and electron conductive composite oxide having oxide ion conductivity and electron conductivity, or a proton and electron conductive composite oxide having proton conductivity and electron conductivity.

[0028] In general formula (1), M is at least one of Ti, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga, and is preferably Y, Gd, or Yb. x1 is 0.90 to 1.10, preferably 0.95 to 1.05, and more preferably 0.95 to 1.00. α1 is greater than 0.00 and equal to or less than 1.00, preferably 0.10 to 0.80, and more preferably 0.20 to 0.40. β1 is greater than 0.00 and equal to or less than 1.00, preferably 0.30 to 0.90, and more preferably 0.40 to 0.80. γ1 is greater than 0.00 and equal to or less than 0.30, preferably 0.05 to 0.25, and more preferably 0.10 to 0.20. δ1 is greater than 0.00 and equal to or less than 0.30, preferably 0.05 to 0.25, and more preferably 0.10 to 0.20. y1 is 0.00 to 0.80, preferably 0.20 to 0.60, and more preferably 0.25 to 0.50. Furthermore, x1 / (α1+β1+γ1+δ1) is preferably 0.90 to 1.10, and more preferably 0.95 to 1.00. Furthermore, x1 / y1 is preferably 1.58 to 5.25, and more preferably 1.90 to 4.00. When M is two or more elements, the value of δ1 is the total value of those two or more elements. That is, the perovskite composite oxide represented by general formula (1) is a perovskite oxide that contains Ba as an essential element at the A site and Co, Fe, Mg, and M as essential elements at the B site in a predetermined molar ratio. Moreover, the perovskite composite oxide represented by general formula (1) does not contain Zr at the B site.

[0029] The perovskite-type composite oxide represented by the general formula (1) includes the following formula (1a): Ba 0.90~1.10 Co 0.00を超え1.00以下 Fe 0.00を超え1.00以下 Mg 0.00を超え0.30以下 Y 0.00を超え0.30以下 O 2.20~3.00 (1a) The general formula (1a) is a perovskite-type composite oxide in which M in the general formula (1) is Y, x1 is 0.90 to 1.10, α1 is more than 0.00 and not more than 1.00, β1 is more than 0.00 and not more than 1.00, γ1 is more than 0.00 and not more than 0.30, δ1 is more than 0.00 and not more than 0.30, and y1 is 2.20 to 3.00.

[0030] The perovskite type composite oxide represented by the general formula (1) may be one type or a combination of two or more types, as long as it satisfies the general formula (1).

[0031] The average particle size of the perovskite-type composite oxide represented by general formula (1) is preferably 0.05 to 2.0 μm, more preferably 0.10 to 1.0 μm. When the average particle size of the perovskite-type proton-conducting oxide represented by general formula (1) is within the above range, the reaction resistance of the air electrode is reduced.

[0032] In the present invention, the average particle size of the oxide is determined from a cross-sectional image of the proton-conductive ceramic fuel cell air electrode material observed with a scanning electron microscope (SEM).

[0033] The oxygen permeation rate of the perovskite-type composite oxide represented by the general formula (1) is preferably 50 nmol / cm 2 ·s or more, preferably 80nmol / cm 2 ·s or more. When the oxygen transmission rate of the perovskite-type composite oxide represented by general formula (1) is in the above range, the reaction resistance of the air electrode is reduced.

[0034] The total conductivity of the perovskite complex oxide represented by general formula (1) is preferably 1.0 S / cm or more, and more preferably 2.0 S / cm or more.

[0035] The second aspect of the present invention provides a proton-conducting ceramic fuel cell air electrode material represented by the following general formula (2): Ba x2 Co α2 Fe β2 Ni γ2 M δ2 O 3-y2 (2) (In formula (2), M is at least one of Mg, Ti, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x2 is 0.90 to 1.10; α2 is greater than 0.00 and less than or equal to 1.00; β2 is greater than 0.00 and less than or equal to 1.00; γ2 is greater than 0.00 and less than or equal to 0.30; δ2 is greater than 0.00 and less than or equal to 0.30; and y2 is 0.00 to 0.80.) The air electrode material for proton-conducting ceramic fuel cells is characterized by being a perovskite-type composite oxide represented by the following general formula (2): The perovskite-type composite oxide represented by the following general formula (2) is either an oxide ion and electron conductive composite oxide having oxide ion conductivity and electron conductivity, or a proton and electron conductive composite oxide having proton conductivity and electron conductivity.

[0036] In general formula (2), M is at least one of Mg, Ti, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga, and is preferably Y, Gd, or Yb. x2 is 0.90 to 1.10, preferably 0.95 to 1.05, and more preferably 0.95 to 1.00. α2 is greater than 0.00 and equal to or less than 1.00, preferably 0.10 to 0.80, and more preferably 0.20 to 0.40. β2 is greater than 0.00 and equal to or less than 1.00, preferably 0.30 to 0.90, and more preferably 0.40 to 0.80. γ2 is greater than 0.00 and equal to or less than 0.30, preferably 0.05 to 0.25, and more preferably 0.10 to 0.20. δ2 is greater than 0.00 and equal to or less than 0.30, preferably 0.05 to 0.25, and more preferably 0.10 to 0.20. y2 is 0.00 to 0.80, preferably 0.20 to 0.60, and more preferably 0.25 to 0.50. Furthermore, x2 / (α2+β2+γ2+δ2) is preferably 0.90 to 1.10, and more preferably 0.95 to 1.00. Furthermore, x2 / y2 is preferably 1.58 to 5.25, and more preferably 1.90 to 4.00. When M is two or more elements, the value of δ2 is the total value of those two or more elements. That is, the perovskite composite oxide represented by general formula (2) is a perovskite oxide that contains Ba as an essential element at the A site and Co, Fe, Ni, and M as essential elements at the B site in a predetermined molar ratio. Moreover, the perovskite composite oxide represented by general formula (2) does not contain Zr at the B site.

[0037] The perovskite-type proton-conducting oxide represented by the general formula (2) includes the following formula (2a): Ba 0.90~1.10 Co 0.00を超え1.00以下 Fe 0.00を超え1.00以下 Ni 0.00を超え0.30以下 Y 0.00を超え0.30以下 O 2.20~3.00 (2a) The general formula (2a) is a perovskite-type composite oxide represented by the following general formula (2): M is Y, x2 is 0.90 to 1.10, α2 is more than 0.00 and not more than 1.00, β2 is more than 0.00 and not more than 1.00, γ2 is more than 0.00 and not more than 0.30, δ2 is more than 0.00 and not more than 0.30, and y2 is 2.20 to 3.00.

[0038] The perovskite type composite oxide represented by the general formula (2) may be one type or a combination of two or more types, as long as it satisfies the general formula (2).

[0039] The average particle size of the perovskite-type composite oxide represented by general formula (2) is preferably 0.05 to 2.0 μm, more preferably 0.10 to 1.0 μm. When the average particle size of the perovskite-type proton-conducting oxide represented by general formula (2) is within the above range, the reaction resistance of the air electrode is reduced.

[0040] The oxygen permeation rate of the perovskite-type composite oxide represented by the general formula (2) is preferably 50 nmol / cm 2 ·s or more, preferably 80nmol / cm 2·s or more. When the oxygen transmission rate of the perovskite-type composite oxide represented by general formula (2) is in the above range, the reaction resistance of the air electrode is reduced.

[0041] The total conductivity of the perovskite complex oxide represented by the general formula (2) is preferably 1.0 S / cm or more, and more preferably 2.0 S / cm or more.

[0042] A proton-conductive ceramic fuel cell air electrode material according to a third aspect of the present invention is a material represented by the following general formula (3): Ba x3 Co α3 Fe β3 Zn γ3 M δ3 O 3-y3 (3) (In formula (3), M is at least one of Mg, Ti, Ni, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x3 is 0.90 to 1.10; α3 is greater than 0.00 and less than or equal to 1.00; β3 is greater than 0.00 and less than or equal to 1.00; γ3 is greater than 0.00 and less than or equal to 0.30; δ3 is greater than 0.00 and less than or equal to 0.30; and y3 is 0.00 to 0.80.) The air electrode material for proton-conducting ceramic fuel cells is characterized by being a perovskite-type composite oxide represented by the following general formula (3): The perovskite-type composite oxide represented by the general formula (3) is either an oxide ion and electron conductive composite oxide having oxide ion conductivity and electron conductivity, or a proton and electron conductive composite oxide having proton conductivity and electron conductivity.

[0043] In general formula (3), M is at least one of Mg, Ti, Ni, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga, and is preferably Y, Gd, or Yb. x3 is 0.90 to 1.10, preferably 0.95 to 1.05, and more preferably 0.95 to 1.00. α3 is greater than 0.00 and equal to or less than 1.00, preferably 0.10 to 0.80, and more preferably 0.20 to 0.40. β3 is greater than 0.00 and equal to or less than 1.00, preferably 0.30 to 0.90, and more preferably 0.40 to 0.80. γ3 is greater than 0.00 and equal to or less than 0.30, preferably 0.05 to 0.25, and more preferably 0.10 to 0.20. δ3 is greater than 0.00 and equal to or less than 0.30, preferably 0.05 to 0.25, and more preferably 0.10 to 0.20. y3 is 0.00 to 0.80, preferably 0.20 to 0.60, and more preferably 0.25 to 0.50. Furthermore, x3 / (α3+β3+γ3+δ3) is preferably 0.90 to 1.10, and more preferably 0.95 to 1.00. Furthermore, x3 / y3 is preferably 1.58 to 5.25, and more preferably 1.90 to 4.00. When M is two or more elements, the value of δ3 is the total value of those two or more elements. That is, the perovskite composite oxide represented by general formula (3) is a perovskite oxide that contains Ba as an essential element at the A site and Co, Fe, Zn, and M as essential elements at the B site in a predetermined molar ratio. Moreover, the perovskite composite oxide represented by general formula (3) does not contain Zr at the B site.

[0044] The perovskite-type composite oxide represented by the general formula (3) includes the following formula (3a): Ba 0.90~1.10 Co 0.00を超え1.00以下 Fe 0.00を超え1.00以下 Zn 0.00を超え0.30以下 Y 0.00を超え0.30以下 O 2.20~3.00 (3a) The general formula (3a) is a perovskite-type composite oxide in which M in the general formula (3) is Y, x3 is 0.90 to 1.10, α3 is more than 0.00 and not more than 1.00, β3 is more than 0.00 and not more than 1.00, γ3 is more than 0.00 and not more than 0.30, δ3 is more than 0.00 and not more than 0.30, and y3 is 2.20 to 3.00.

[0045] The perovskite type composite oxide represented by the general formula (3) may be one type or a combination of two or more types, as long as it satisfies the general formula (3).

[0046] The average particle size of the perovskite-type composite oxide represented by general formula (3) is preferably 0.05 to 2.0 μm, more preferably 0.10 to 1.0 μm. When the average particle size of the perovskite-type composite oxide represented by general formula (3) is within the above range, the reaction resistance of the air electrode is reduced.

[0047] The oxygen permeation rate of the perovskite-type composite oxide represented by the general formula (3) is preferably 50 nmol / cm 2 ·s or more, preferably 80nmol / cm 2 ·s or more. When the oxygen transmission rate of the perovskite-type composite oxide represented by general formula (3) is in the above range, the reaction resistance of the air electrode is reduced.

[0048] The total conductivity of the perovskite complex oxide represented by the general formula (3) is preferably 1.0 S / cm or more, and more preferably 2.0 S / cm or more.

[0049] A fourth aspect of the present invention provides a proton-conducting ceramic fuel cell air electrode material represented by the following general formula (4): Ba x4 Co α4 Fe β4 Ti γ4 M δ4 O 3-y4 (4) (In formula (4), M is at least one of Mg, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x4 is 0.90 to 1.10; α4 is more than 0.00 and not more than 1.00; β4 is more than 0.00 and not more than 1.00; γ4 is more than 0.00 and not more than 0.30; δ4 is more than 0.00 and not more than 0.30; and y4 is 0.00 to 0.80.) The air electrode material for a proton-conductive ceramic fuel cell is characterized by being a perovskite-type composite oxide represented by the following general formula (4): The perovskite-type composite oxide represented by the general formula (4) is either an oxide ion and electron conductive composite oxide having oxide ion conductivity and electron conductivity, or a proton and electron conductive composite oxide having proton conductivity and electron conductivity.

[0050] In general formula (4), M is at least one of Mg, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga, and is preferably Y, Gd, or Yb. x4 is 0.90 to 1.10, preferably 0.95 to 1.05, and more preferably 0.95 to 1.00. α4 is greater than 0.00 and equal to or less than 1.00, preferably 0.10 to 0.80, and more preferably 0.20 to 0.40. β4 is greater than 0.00 and equal to or less than 1.00, preferably 0.30 to 0.90, and more preferably 0.40 to 0.80. γ4 is greater than 0.00 and equal to or less than 0.30, preferably 0.05 to 0.25, and more preferably 0.10 to 0.20. δ4 is greater than 0.00 and equal to or less than 0.30, preferably 0.05 to 0.25, and more preferably 0.10 to 0.20. y4 is 0.00 to 0.80, preferably 0.20 to 0.60, and more preferably 0.25 to 0.50. Furthermore, x4 / (α4+β4+γ4+δ4) is preferably 0.90 to 1.10, and more preferably 0.95 to 1.00. Furthermore, x4 / y4 is preferably 1.58 to 5.25, and more preferably 1.90 to 4.00. When M is two or more elements, the value of δ4 is the total value of those two or more elements. That is, the perovskite composite oxide represented by general formula (4) is a perovskite oxide that contains Ba as an essential element at the A site and Co, Fe, Ti, and M as essential elements at the B site in a predetermined molar ratio. Moreover, the perovskite composite oxide represented by general formula (4) does not contain Zr at the B site.

[0051] The perovskite-type composite oxide represented by the general formula (4) includes the following formula (4a): Ba 0.90~1.10 Co 0.00を超え1.00以下 Fe 0.00を超え1.00以下 Ti 0.00を超え0.30以下 Y 0.00を超え0.30以下 O 2.20~3.00 (3a) The general formula (4a) is a perovskite-type composite oxide in which M in the general formula (4) is Y, x4 is 0.90 to 1.10, α4 is more than 0.00 and not more than 1.00, β4 is more than 0.00 and not more than 1.00, γ4 is more than 0.00 and not more than 0.30, δ4 is more than 0.00 and not more than 0.30, and y4 is 2.20 to 3.00.

[0052] The perovskite type composite oxide represented by the general formula (4) may be one type or a combination of two or more types, as long as it satisfies the general formula (4).

[0053] The average particle size of the perovskite-type composite oxide represented by general formula (4) is preferably 0.05 to 2.0 μm, more preferably 0.10 to 1.0 μm. When the average particle size of the perovskite-type composite oxide represented by general formula (4) is within the above range, the reaction resistance of the air electrode is reduced.

[0054] The oxygen permeation rate of the perovskite-type composite oxide represented by the general formula (4) is preferably 50 nmol / cm 2 ·s or more, preferably 80nmol / cm 2 ·s or more. When the oxygen transmission rate of the perovskite-type composite oxide represented by general formula (4) is in the above range, the reaction resistance of the air electrode is reduced.

[0055] The total conductivity of the perovskite complex oxide represented by the general formula (4) is preferably 1.0 S / cm or more, and more preferably 2.0 S / cm or more.

[0056] The proton-conducting ceramic fuel cell air electrodes according to the first, second, third and fourth aspects of the present invention can reduce the reaction resistance of the air electrode and increase the power density by being used as an air material.

[0057] The air electrode for a proton-conductive ceramic fuel cell of the first embodiment of the present invention contains 30.0 mass % or more of the air electrode material for a proton-conductive ceramic fuel cell of the first embodiment of the present invention. The air electrode for a proton-conductive ceramic fuel cell of the first embodiment of the present invention is porous, and preferably has a porosity of 10.0 to 80.0 volume %.

[0058] The air electrode for a proton-conductive ceramic fuel cell according to the second embodiment of the present invention contains 30.0 mass % or more of the air electrode material for a proton-conductive ceramic fuel cell according to the second embodiment of the present invention. The air electrode for a proton-conductive ceramic fuel cell according to the second embodiment of the present invention is porous, and preferably has a porosity of 10.0 to 80.0 volume %.

[0059] The air electrode for a proton-conductive ceramic fuel cell according to the third embodiment of the present invention contains 30.0 mass % or more of the air electrode material for a proton-conductive ceramic fuel cell according to the third embodiment of the present invention. The air electrode for a proton-conductive ceramic fuel cell according to the third embodiment of the present invention is porous, and preferably has a porosity of 10.0 to 80.0 volume %.

[0060] The air electrode for a proton-conductive ceramic fuel cell according to the fourth aspect of the present invention contains 30.0 mass % or more of the air electrode material for a proton-conductive ceramic fuel cell according to the fourth aspect of the present invention. The air electrode for a proton-conductive ceramic fuel cell according to the fourth aspect of the present invention is porous, and preferably has a porosity of 10.0 to 80.0 volume %.

[0061] The air electrodes for proton-conductive ceramic fuel cells of the first, second, third and fourth embodiments of the present invention are similar except that the air electrode material contained in the air electrode is the air electrode material for proton-conductive ceramic fuel cells of the first, second, third and fourth embodiments of the present invention, respectively. Therefore, hereinafter, in order to describe the points common to the air electrodes for proton-conductive ceramic fuel cells of the first, second, third and fourth embodiments of the present invention, the air electrodes for proton-conductive ceramic fuel cells of the first, second, third and fourth embodiments of the present invention will be collectively referred to as the air electrodes for proton-conductive ceramic fuel cells of the present invention.

[0062] The air electrode for a proton-conductive ceramic fuel cell according to the first embodiment of the present invention is mainly composed of the air electrode material for a proton-conductive ceramic fuel cell according to the first embodiment of the present invention. The air electrode for a proton-conductive ceramic fuel cell according to the first embodiment of the present invention may contain, in addition to the air electrode material for a proton-conductive ceramic fuel cell according to the first embodiment of the present invention, a proton-conductive oxide, an electron-conductive oxide, an oxide-ion-conductive oxide, alumina for adjusting the thermal expansion coefficient, or the like, within a range that does not impair the effects of the present invention.

[0063] The air electrode for a proton-conductive ceramic fuel cell according to the second embodiment of the present invention is mainly composed of the air electrode material for a proton-conductive ceramic fuel cell according to the second embodiment of the present invention. The air electrode for a proton-conductive ceramic fuel cell according to the second embodiment of the present invention may contain, in addition to the air electrode material for a proton-conductive ceramic fuel cell according to the second embodiment of the present invention, a proton-conductive oxide, an electron-conductive oxide, an oxide-ion-conductive oxide, alumina for adjusting the thermal expansion coefficient, or the like, within a range that does not impair the effects of the present invention.

[0064] The air electrode for a proton-conductive ceramic fuel cell according to the third aspect of the present invention is mainly composed of the air electrode material for a proton-conductive ceramic fuel cell according to the third aspect of the present invention. The air electrode for a proton-conductive ceramic fuel cell according to the third aspect of the present invention may contain, in addition to the air electrode material for a proton-conductive ceramic fuel cell according to the third aspect of the present invention, a proton-conductive oxide, an electron-conductive oxide, an oxide-ion-conductive oxide, alumina for adjusting the thermal expansion coefficient, or the like, within a range that does not impair the effects of the present invention.

[0065] The air electrode for a proton-conductive ceramic fuel cell according to the fourth aspect of the present invention is mainly composed of the air electrode material for a proton-conductive ceramic fuel cell according to the fourth aspect of the present invention. The air electrode for a proton-conductive ceramic fuel cell according to the fourth aspect of the present invention may contain, in addition to the air electrode material for a proton-conductive ceramic fuel cell according to the fourth aspect of the present invention, a proton-conductive oxide, an electron-conductive oxide, an oxide-ion-conductive oxide, alumina for adjusting the thermal expansion coefficient, or the like, within a range that does not impair the effects of the present invention.

[0066] In the proton-conductive ceramic fuel cell air electrode of the present invention, the content of the proton-conductive ceramic fuel cell air electrode material of the present invention is 30.0 mass% or more, preferably 50.0 mass% or more, more preferably 70.0 mass% or more, and particularly preferably 100.0 mass%. When the content of the proton-conductive ceramic fuel cell air electrode material of the present invention in the air electrode is within the above range, the reaction resistance of the air electrode can be low and the power density can be increased.

[0067] The proton-conductive ceramic fuel cell air electrode of the present invention is preferably porous. The porosity of the proton-conductive ceramic fuel cell air electrode of the present invention is 10.0 to 80.0 vol%, preferably 30.0 to 60.0 vol%, and more preferably 40.0 to 50.0 vol%. When the porosity of the proton-conductive ceramic fuel cell air electrode is within the above range, the contact area with the electrolyte and the reaction field within the air electrode are expanded, thereby reducing the reaction resistance of the air electrode and increasing the current density.

[0068] In the present invention, the porosity is determined by binarizing and separating the cathode material and voids in a cross-sectional image of the cathode for a proton-conductive ceramic fuel cell observed with a scanning electron microscope (SEM).

[0069] The thickness of the air electrode for a proton-conductive ceramic fuel cell of the present invention is preferably 5.0 to 50.0 μm, more preferably 10.0 to 20.0 μm. When the thickness of the air electrode is within the above range, the gas diffusion resistance, which is part of the electrode resistance, is reduced, thereby lowering the electrode resistance and increasing the current density.

[0070] The electrode resistance of the proton-conductive ceramic fuel cell air electrode of the present invention is preferably 0.08 Ω cm 2 Less than or equal to 0.06 Ω·cm, preferably 0.06 Ω·cm 2 The following is the result.

[0071] A proton-conducting ceramic fuel cell according to a first embodiment of the present invention (hereinafter also referred to as the proton-conducting ceramic fuel cell (1) of the present invention) has an air electrode, an electrolyte, and an anode, which are formed in this order: air electrode / electrolyte / anode; the air electrode is the proton-conducting ceramic fuel cell air electrode of the present invention, The electrolyte is represented by the following general formula (6): Ba x6 (Zr α6 Ce β6 B6 (1-α6-β6) ) y6 O 3+z6 (6) (In formula (6), B6 ​​is at least one of Sc, Ga, Y, In, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf, x6 is 0.80 to 1.20, α6 is 0.10 to 0.90, β6 is 0.00 to 0.10, y6 is 0.80 to 1.20, and z6 is −0.80 to +0.80.) The perovskite-type proton-conductive oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conductive oxide represented by the formula (I). The proton-conducting ceramic fuel cell is characterized by the above.

[0072] The proton-conductive ceramic fuel cell (1) of the present invention has, as a layer structure of the fuel cell, at least an air electrode for the proton-conductive ceramic fuel cell, an electrolyte for the proton-conductive ceramic fuel cell, and a fuel electrode for the proton-conductive ceramic fuel cell, and has a configuration in which the air electrode, electrolyte, and fuel electrode are formed in the order of air electrode / electrolyte / fuel electrode.

[0073] A first embodiment of the proton-conductive ceramic fuel cell (1) of the present invention is an embodiment in which the air electrode of the proton-conductive ceramic fuel cell (1) of the present invention is the air electrode for a proton-conductive ceramic fuel cell of the first embodiment of the present invention. A second embodiment of the proton-conductive ceramic fuel cell (1) of the present invention is an embodiment in which the air electrode of the proton-conductive ceramic fuel cell (1) of the present invention is the air electrode for a proton-conductive ceramic fuel cell of the second embodiment of the present invention. A third embodiment of the proton-conductive ceramic fuel cell (1) of the present invention is an embodiment in which the air electrode of the proton-conductive ceramic fuel cell (1) of the present invention is the air electrode for a proton-conductive ceramic fuel cell of the third embodiment of the present invention. A fourth embodiment of the proton-conductive ceramic fuel cell (1) of the present invention is an embodiment in which the air electrode of the proton-conductive ceramic fuel cell (1) of the present invention is the air electrode for a proton-conductive ceramic fuel cell of the fourth embodiment of the present invention.

[0074] A proton-conducting ceramic fuel cell according to a second embodiment of the present invention (hereinafter also referred to as a proton-conducting ceramic fuel cell (2) of the present invention) has an air electrode, an intermediate layer, an electrolyte, and an anode, which are formed in this order: air electrode / intermediate layer / electrolyte / anode; the air electrode is the proton-conducting ceramic fuel cell air electrode of the present invention, The electrolyte is represented by the following general formula (6): Ba x6 (Zr α6 Ce β6 B6 (1-α6-β6) ) y6 O 3+z6 (6) (In formula (6), B6 ​​is at least one of Sc, Ga, Y, In, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf, x6 is 0.80 to 1.20, α6 is 0.10 to 0.90, β6 is 0.00 to 0.10, y6 is 0.80 to 1.20, and z6 is −0.80 to +0.80.) The perovskite-type proton-conductive oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conductive oxide represented by the formula (I). The intermediate layer is formed of a polymer represented by the following general formula (7): A7 x7 B7 y7 O 3+z7 (7) (In formula (7), A7 is at least one of Ca, Sr, Ba, and La; B7 is at least one of Sc, Ga, Y, Zr, In, Ce, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf; x7 is 0.80 to 1.20; y7 is 0.80 to 1.20; and z7 is −0.80 to +0.80.) The perovskite-type proton-conductive oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conductive oxide represented by the formula (I). The proton-conducting ceramic fuel cell is characterized by the above.

[0075] The proton-conductive ceramic fuel cell (2) of the present invention has, as a layer configuration of the fuel cell, at least an air electrode for the proton-conductive ceramic fuel cell, an intermediate layer, an electrolyte for the proton-conductive ceramic fuel cell, and an anode for the proton-conductive ceramic fuel cell, and has a configuration having an air electrode, an intermediate layer, an electrolyte, and an anode formed in the order of air electrode / intermediate layer / electrolyte / anode.

[0076] A first embodiment of the proton-conductive ceramic fuel cell (2) of the present invention is an embodiment in which the air electrode of the proton-conductive ceramic fuel cell (2) of the present invention is the air electrode for a proton-conductive ceramic fuel cell of the first embodiment of the present invention. A second embodiment of the proton-conductive ceramic fuel cell (2) of the present invention is an embodiment in which the air electrode of the proton-conductive ceramic fuel cell (2) of the present invention is the air electrode for a proton-conductive ceramic fuel cell of the second embodiment of the present invention. A third embodiment of the proton-conductive ceramic fuel cell (2) of the present invention is an embodiment in which the air electrode of the proton-conductive ceramic fuel cell (2) of the present invention is the air electrode for a proton-conductive ceramic fuel cell of the third embodiment of the present invention. A fourth embodiment of the proton-conductive ceramic fuel cell (2) of the present invention is an embodiment in which the air electrode of the proton-conductive ceramic fuel cell (2) of the present invention is the air electrode for a proton-conductive ceramic fuel cell of the fourth embodiment of the present invention.

[0077] The electrolyte is mainly a compound represented by the following general formula (6): Ba x6 (Zr α6 Ce β6 B6 (1-α6-β6) ) y6 O 3+z6 (6) (In formula (6), B6 ​​is at least one of Sc, Ga, Y, In, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf, x6 is 0.80 to 1.20, α6 is 0.10 to 0.90, β6 is 0.00 to 0.10, y6 is 0.80 to 1.20, and z6 is −0.80 to +0.80.) The proton-conducting oxide is a perovskite-type oxide represented by the formula:

[0078] In general formula (6), B6 ​​is at least one of Sc, Ga, Y, In, Gd, Dy, Ho, Er, Tm, Yb, Lu and Hf, preferably at least one of Y and Yb, more preferably Yb. x6 is 0.80 to 1.20, preferably 0.90 to 1.10, and more preferably 0.95 to 1.05. α6 is 0.10 to 0.90, preferably 0.50 to 0.90, and more preferably 0.75 to 0.85. β6 is 0.00 to 0.10, preferably 0.00 to 0.05, and more preferably 0.00 to 0.02. y6 is 0.80 to 1.20, preferably 0.90 to 1.10, and more preferably 0.95 to 1.05. z6 is −0.80 to +0.80, preferably −0.40 to +0.40, and more preferably −0.20 to +0.00. When B6 is two or more elements, the value of 1-α6-β6 is the total value of those two or more elements, and the value of y6 is the total value of Zr, Ce, and those two or more elements. That is, the perovskite-type proton-conducting oxide represented by general formula (6) is a perovskite-type oxide containing Ba as an essential element in the A site and Zr as an essential element in the B site at a predetermined molar ratio.

[0079] The perovskite-type proton-conducting oxide represented by the general formula (6) includes the following formula (6a): Ba 0.80~1.20 Zr 0.10~0.90 Yb 0.00~0.90 O 2.20~3.80 (6a) Preferred is a perovskite-type proton-conducting oxide represented by the following formula: In addition, the general formula (6a) is a perovskite-type composite oxide in which β6 in the general formula (6) is 0.00, that is, it does not contain Ce and B6 is Yb.

[0080] The perovskite-type proton-conducting oxide represented by the general formula (6) may be one type or a combination of two or more types, as long as it satisfies the general formula (6).

[0081] The intermediate layer is mainly composed of a polymer represented by the following general formula (7): A7 x7 B7 y7 O 3+z7 (7) (In formula (7), A7 is at least one of Ca, Sr, Ba, and La; B7 is at least one of Sc, Ga, Y, Zr, In, Ce, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf; x7 is 0.80 to 1.20; y7 is 0.80 to 1.20; and z7 is −0.80 to +0.80.) The proton-conducting oxide is a perovskite-type oxide represented by the formula:

[0082] In the general formula (7), A7 is at least one of Ca, Sr, Ba and La, and is preferably Ba. B7 is at least one of Sc, Ga, Y, Zr, In, Ce, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf, and preferably at least one of Y, Zr, Ce, and Yb. x7 is 0.80 to 1.20, preferably 0.90 to 1.10, and more preferably 0.95 to 1.05. y7 is 0.80 to 1.20, preferably 0.90 to 1.10, and more preferably 0.95 to 1.05. z7 is −0.80 to +0.80, preferably −0.40 to +0.40, and more preferably −0.20 to +0.00. If A7 is two or more elements, the value of x7 is the total value of those two or more elements. If B7 is two or more elements, the value of y7 is the total value of those two or more elements.

[0083] The perovskite-type proton-conducting oxide represented by the general formula (7) includes the following formula (7a): Ba 0.80~1.20 Ce 0.10~0.80 Zr 0.10~0.80 Y 0.00~0.20 Yb 0.00~0.20 O 2.20~3.80 (7a) Preferred is a perovskite-type proton-conducting oxide represented by the following formula: General formula (7a) is a perovskite-type composite oxide in which A7 in general formula (7) is Ba, and B7 is Ce, Zr, Y, or Yb.

[0084] The perovskite-type proton-conducting oxide represented by the general formula (7) may be one type or a combination of two or more types, as long as it satisfies the general formula (7).

[0085] The electrolyte for the proton-conductive ceramic fuel cell (1) of the present invention and the proton-conductive ceramic fuel cell (2) of the present invention contains 80.0 mass % or more of a perovskite-type proton-conductive oxide represented by general formula (6). The electrolyte for the proton-conductive ceramic fuel cell (1) of the present invention and the proton-conductive ceramic fuel cell (2) of the present invention preferably has a relative density of 90.0 to 100.0 volume %.

[0086] The electrolyte in the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention is mainly composed of a perovskite-type proton-conducting oxide represented by general formula (6). In the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention, the electrolyte is mainly composed of a perovskite-type proton-conducting oxide represented by general formula (6), and therefore has high proton conductivity and high chemical stability, thereby enabling a high power density and high durability.

[0087] Furthermore, the electrolytes for the proton-conducting ceramic fuel cell (1) and the proton-conducting ceramic fuel cell (2) of the present invention may contain proton-conducting oxides, electron-conducting oxides, oxide-ion-conducting oxides, and the like, in addition to the perovskite-type proton-conducting oxide represented by general formula (6), within the range that does not impair the effects of the present invention.

[0088] In the electrolyte of the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention, the content of the perovskite-type proton-conducting oxide represented by general formula (6) is 80.0 mass% or more, preferably 90.0 mass% or more, more preferably 95.0 mass% or more, and particularly preferably 100.0 mass%. When the content of the perovskite-type proton-conducting oxide represented by general formula (6) in the electrolyte is within the above range, the proton conductivity of the electrolyte can be high and the power density can be increased.

[0089] The relative density of the electrolyte in the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention is 90.0 to 100.0% by volume, preferably 96.0 to 100.0% by volume, and more preferably 98.0 to 100.0% by volume. When the relative density of the electrolyte is in the above range, the gas cross-leak prevention function can be improved.

[0090] In the present invention, the relative density is determined by binarizing and separating the air electrode material and voids in a cross-sectional observation image of the electrolyte of the proton-conducting ceramic fuel cell taken with a scanning electron microscope (SEM).

[0091] The thickness of the electrolyte in the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention is 0.50 to 50.0 μm, preferably 5.0 to 30.0 μm. By keeping the thickness of the electrolyte within the above range, the resistance of the dense layer of the electrolyte can be reduced while maintaining the gas cross leak prevention function.

[0092] The fuel electrode of the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention is mainly made of an electron-conducting oxide material for the fuel electrode of a proton-conducting ceramic fuel cell.

[0093] The electron conductive oxide material for the anode may be a material represented by the following general formula (8): A8O z8 (8) (In the formula (8), A8 is at least one of Ti, Mn, Fe, Co, Ni, and Cu, and z8 is 0.50 to 3.00.) There are no particular limitations on the electron-conductive oxide material for the anode, as long as it is represented by the formula: Examples of electron-conductive oxide materials for the anode include TiO2, MnO2, Fe2O3, CoO, NiO, and CuO.

[0094] The anode may be formed from an electron-conductive oxide material for the anode, or from an electron-conductive oxide material for the anode and a proton-conductive oxide material. The anode may contain an electron-conductive oxide other than the electron-conductive oxide material for the anode, a proton-conductive oxide, an oxide-ion-conductive oxide, or alumina for adjusting the thermal expansion coefficient, as long as the effect of the present invention is not impaired. The proton-conductive oxide material used to form the anode is not particularly limited, and examples thereof include perovskite-type proton-conductive oxides represented by general formula (6).

[0095] The perovskite-type electron-conductive oxide material for the anode may be one type or a combination of two or more types. When a proton-conductive oxide material is used in the anode, the proton-conductive oxide material may be one type or a combination of two or more types.

[0096] In the fuel electrode, the mass ratio of the electron-conductive oxide material for the fuel electrode to the proton-conductive oxide material (electron-conductive oxide material for the fuel electrode:proton-conductive oxide material) is preferably 100:0 to 20:80, more preferably 80:20 to 30:70, and more preferably 60:40 to 40:60. When the mass ratio of the electron-conductive oxide material for the fuel electrode to the proton-conductive oxide material in the fuel electrode is within the above range, the reaction resistance of the fuel electrode can be reduced and the power density can be increased.

[0097] The fuel electrode in the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention is preferably porous. The porosity of the fuel electrode in the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention is preferably 30.0 to 50.0 vol%, more preferably 35.0 to 45.0 vol%. When the porosity of the fuel electrode is within the above range, the gas diffusion resistance, which is part of the electrode resistance, is reduced, thereby reducing the electrode resistance and increasing the current density.

[0098] The thickness of the fuel electrode in the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention is preferably 100 to 700 μm, more preferably 200 to 600 μm. When the thickness of the fuel electrode is within the above range, the gas diffusion resistance, which is part of the electrode resistance, is reduced, thereby reducing the electrode resistance and increasing the current density.

[0099] The intermediate layer is provided for various purposes, such as preventing gas leakage, suppressing electron leakage, reducing the reaction resistance of the air electrode, and improving the adhesive strength of the interface.

[0100] The intermediate layer in the proton-conductive ceramic fuel cell (2) of the present invention contains 80.0 mass % or more of a perovskite-type proton-conductive oxide represented by general formula (7). The intermediate layer in the proton-conductive ceramic fuel cell (2) of the present invention may be either a dense body or a porous body, and preferably has a porosity of 30.0 to 100.0 volume %.

[0101] The intermediate layer of the proton-conducting ceramic fuel cell (2) of the present invention is mainly made of a perovskite-type proton-conducting oxide represented by general formula (7). In the proton-conducting ceramic fuel cell (2) of the present invention, the intermediate layer is mainly made of a perovskite-type proton-conducting oxide represented by general formula (7), and therefore has high proton conductivity and high chemical stability, thereby enabling a high power density and high durability.

[0102] Furthermore, the intermediate layer of the proton-conducting ceramic fuel cell (2) of the present invention may contain, in addition to the perovskite-type proton-conducting oxide represented by the general formula (7), a proton-conducting oxide, an electron-conducting oxide, an oxide-ion-conducting oxide, alumina for adjusting the thermal expansion coefficient, or the like, within the range that does not impair the effects of the present invention.

[0103] In the intermediate layer of the proton-conducting ceramic fuel cell (2) of the present invention, the content of the perovskite-type proton-conducting oxide represented by general formula (7) is 80.0 mass% or more, preferably 90.0 mass% or more, more preferably 95.0 mass% or more, and particularly preferably 100.0 mass%. When the content of the perovskite-type proton-conducting oxide represented by general formula (7) in the intermediate layer is within the above range, the reaction resistance of the air electrode can be reduced and the power density can be increased.

[0104] The intermediate layer in the proton-conducting ceramic fuel cell (2) of the present invention may be either a dense body or a porous body. The porosity of the intermediate layer in the proton-conducting ceramic fuel cell (2) of the present invention is 30.0 to 100.0% by volume, preferably 40.0 to 100.0% by volume. When the porosity of the intermediate layer is within the above range, the resistance of the intermediate layer can be reduced.

[0105] The thickness of the intermediate layer in the proton-conducting ceramic fuel cell (2) of the present invention is preferably 1.0 to 20.0 μm, more preferably 1.0 to 10.0 μm. When the thickness of the intermediate layer is within the above range, the resistance of the intermediate layer can be reduced.

[0106] The maximum power density of the proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention is preferably 0.63 W / cm 2 More than 0.65W / cm 2 That's all.

[0107] In the present invention, the air electrode, electrolyte, anode, or intermediate layer is formed by preparing a slurry in which at least a powdered air electrode material, a powdered electrolyte material, a powdered anode material, or a powdered intermediate layer material is dispersed, applying the slurry to an object to form a slurry coating, drying the coating, and then firing at a firing temperature of, for example, 700 to 1400°C to sinter it.

[0108] The proton-conducting ceramic fuel cell (1) of the present invention and the proton-conducting ceramic fuel cell (2) of the present invention may be formed on a support. The support is preferably a porous body in that good gas diffusion can be achieved. The porosity of the porous support is, for example, 10 to 60% by volume. The shape of the porous support may be a flat plate or a tube, but is not particularly limited. Examples of materials for the support include oxides such as alumina or zirconia, or heat-resistant metals.

[0109] The proton-conducting ceramic fuel cell (1) and the proton-conducting ceramic fuel cell (2) of the present invention may have a porous layer on an electrode (air electrode or fuel electrode) having a porosity higher than that of the electrode. The porosity of the porous layer is higher than that of the electrode, preferably 25.0 to 55.0% by volume. Examples of materials for the porous layer include perovskite-type oxide materials such as (LaBa)MnO3, (LaBa)FeO3, (LaBa)CoO3, and (LaBa)(CoFe)O3. In the above electron-conducting materials, La can be substituted or partially substituted with other lanthanides (Pr, Sm, Gd), and Ba can be substituted or partially substituted with other alkaline earth metals (Ca, Sr). Metal-based materials (Ti, Mn, Fe, Co, Ni, Cu, etc.) are also used as materials for the porous layer. 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, when a solid oxide cell is constructed and operated with the above gases, the NiO will be reduced to Ni (metal). [Example]

[0110] Next, the present invention will be described in more detail with reference to examples, but these are merely illustrative and do not limit the present invention.

[0111] Example 1 (1) Synthesis of battery materials <BaCo 0.4 Fe 0.4 Mg 0.1 Y 0.1Synthesis of O3(BCFMgY) The target composition is BaCo 0.4 Fe 0.4 Mg 0.1 Y 0.1 O 3-δ BaCO3 (99.9%), Co(NO3)2·6H2O (99.9%), Fe(NO3)3·9H2O (99.9%), MgO (99.9%), and Y(NO3)3·6H2O (99.9%) were weighed as the starting materials. Each was placed in a beaker, ion-exchanged water was added, and the mixture was dissolved by stirring using a hot stirrer. Citric acid (99.5%) and ethylene glycol (99.5%) were then added to form a precursor solution. The temperature of this precursor solution was gradually increased to 450°C and calcined at this temperature for approximately 2 hours to obtain a gel. This gel was crushed and then decarbonized by holding it at 650°C for 10 hours, followed by calcination at 900°C for 10 hours. The calcined powder was crushed in a mortar and then wet ball milled for approximately 17 hours. The powder was then dried using a rotary evaporator (Tokyo Rikakikai, N-1110). This dried powder was mixed in a mortar and granulated by passing it through a sieve with 100 μm openings. This granulated powder was filled into a mold and uniaxially pressed at 200 MPa, followed by cold isostatic pressing (CIP) at 300 MPa to produce a pellet-shaped compact. This was then sintered at 1200°C for 10 hours to obtain a sintered body. The heating rate was 3°C / min. The obtained sintered body was crushed in a mortar, then subjected to a wet ball mill treatment, and the powder was dried using a rotary evaporator. This dried powder was obtained as an air electrode material and used in the air electrode. The obtained sintered body was also used to measure the oxygen transmission rate (J O2 ), total conductivity (σ t ) was evaluated.

[0112] <BaZr 0.8 Yb 0.2 O3(BZYb)> Manufactured by Kusaka Rare Metals

[0113] <BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 O3(BCZYYb)> DOWA Electronics Co., Ltd.

[0114] <Evaluation of complex oxides> (Oxygen transmission rate (J O2 )) The sintered sample was placed between two alumina tubes. To create an oxygen partial pressure difference between the two ends of the sample, air (high oxygen partial pressure) was flowed through the lower alumina tube, while helium gas (low oxygen partial pressure) was flowed through the upper alumina tube. The oxygen permeation rate was measured from the amount of O2 gas that permeated through the lower oxygen partial pressure side. A silver ring made of 1.0 mm diameter silver wire was used as a seal between the sample and the alumina. The silver ring was sandwiched between the sample and the alumina tube and softened at 950–960°C to form a seal. After sealing, the temperature was reduced in 25°C increments from 950°C to 550°C, and the oxygen permeation rate was measured by holding each temperature for 2 hours. The helium flow rate was 20 sccm. The gas from the helium atmosphere side was introduced into a gas chromatograph (Agilent, 490-GC) to measure the oxygen and nitrogen concentrations (%). The concentration of oxygen that had leaked mechanically was calculated from the obtained nitrogen concentration, and the concentration of oxygen that had permeated was determined by subtracting this leaked oxygen concentration from the oxygen concentration obtained by gas chromatography. The oxygen permeation rate (J O2 The results are shown in Table 1.

[0115] (Total conductivity (σ t )) The sintered sample was polished to a thickness of approximately 1 mm and gold electrodes were attached. To make the gold electrodes porous, 10 wt% of carbon (purity: 99.7%) was added to the gold paste. After application, the sample was baked at 850°C for 1 hour. The total conductivity (σ t The measurement temperature range was from room temperature to 900° C. The results are shown in Table 1.

[0116] (2) Fabrication of proton-conducting ceramic fuel cells <Fabrication of fuel electrode> NiO (Sumitomo Metal Mining Co., Ltd.) and BaZr 0.8 Yb 0.2O3 and carbon (Showa Denko K.K.) were mixed in a mass ratio of 6:4:1, and a toluene-based solvent, binder, plasticizer, and dispersant were added. The mixture was then mixed in a ball mill for 48 hours to obtain a slurry for the anode. The slurry for the anode was tape-cast to obtain a green sheet for the anode. The green sheets for the anode were laminated to a thickness of approximately 0.9 mm, and the thickness of the green sheet for the anode was adjusted.

[0117] <Preparation of electrolyte> BaZr 0.8 Yb 0.2 A toluene-based solvent, binder, plasticizer, and dispersant were added to O3 and mixed in a ball mill for 48 hours to obtain a slurry for the electrolyte. The electrolyte slurry was tape-cast to obtain a green sheet for the electrolyte. A green sheet for the electrolyte was placed on top of a stack of green sheets for the anode, and hot-pressed. The resulting mixture was then co-sintered at 1470°C for 2 hours to obtain an integrated body of electrolyte and anode. The resulting electrolyte was densified by the high-temperature co-sintering.

[0118] <Creating the intermediate layer> BaCe 0.7 Zr 0.1 Y 0.1 Yb 0.1 Toluene-based solvent, binder, plasticizer, and dispersant were added to O3 and mixed in a ball mill for 48 hours to obtain a slurry for the intermediate layer. The slurry for the intermediate layer was applied to the electrolyte surface of the integrated electrolyte-anode composite by spin coating at 1000 rpm. The composite was then sintered at 1300°C for 1 hour to obtain an integrated electrolyte-anode-intermediate layer composite.

[0119] <Creating the air electrode> BaCo 0.4 Fe 0.4 Mg 0.1 Y 0.1Ethyl cellulose, plasticizer, dispersant, and α-terpineol were added to O3 and mixed in a mixer at room temperature for 4 minutes and 30 seconds to obtain a slurry for the air electrode. The resulting slurry for the air electrode was applied to the surface of the intermediate layer of the integrated body of the electrolyte, fuel electrode, and intermediate layer using a screen printing method to a diameter of 6 mm. The mixture was dried at 150°C for 1 minute to obtain a coating of the electrode material precursor. The mixture was then baked at 1000°C for 1 hour to obtain the air electrode. In this way, a proton-conducting ceramic fuel cell A was obtained.

[0120] <Performance evaluation of proton-conducting ceramic fuel cells> (Maximum power density (MPD), electrode resistance (R p )) For the proton-conducting ceramic cell, an electrochemical measurement system (potentiostat / galvanostat, VSP, manufactured by Biologic) was used to supply humidified hydrogen at 30°C to the fuel electrode and humidified air at 30°C to the air electrode, and current-voltage characteristics and electrochemical impedance measurements were performed at 600°C. The maximum power density (MPD) was calculated from the results of the current-voltage characteristic measurements. In addition, the electrode resistance (R p ) was sought.

[0121] Example 2 (1) Synthesis of battery materials <BaCo 0.4 Fe 0.4 Ni 0.1 Y 0.1 Synthesis of O3(BCFNiY) The target composition is BaCo 0.4 Fe 0.4 Ni 0.1 Y 0.1BaCO3 (99.95%), Co(NO3)2·6H2O (99.9%), Fe(NO3)3·9H2O (99.9%), Ni(NO3)2·6H2O (99.9%), and Y(NO3)3·6H2O (99.9%) were weighed as the O3. Each was placed in a beaker, ion-exchanged water was added, and the mixture was dissolved by stirring using a hot stirrer. Citric acid (99.5%) and ethylene glycol (99.5%) were then added to form a precursor solution. The temperature of this precursor solution was gradually increased to 450°C and calcined at this temperature for approximately 2 hours to obtain a gel. This gel was crushed, decarbonized by holding it at 650°C for 10 hours, and then calcined at 900°C for 10 hours. The calcined powder was crushed in a mortar and wet ball milled for approximately 17 hours. The powder was then dried using a rotary evaporator (Tokyo Rikakikai, N-1110). This dried powder was mixed in a mortar and granulated by passing it through a sieve with 100 μm openings. This granulated powder was filled into a mold and uniaxially pressed at 200 MPa, followed by cold isostatic pressing (CIP) at 300 MPa to produce a pellet-shaped compact. This was then sintered at 1200°C for 10 hours to obtain a sintered body. The heating rate was 3°C / min. The obtained sintered body was crushed in a mortar, then subjected to a wet ball mill treatment, and the powder was dried using a rotary evaporator. This dried powder was obtained as an air electrode material and used in the air electrode. The obtained sintered body was also used to measure the oxygen transmission rate (J O2 ), total conductivity (σ t The results are shown in Table 1.

[0122] (2) Fabrication of proton-conducting ceramic fuel cells BaCo as the cathode material 0.4 Fe 0.4 Mg 0.1 Y 0.1 BaCo instead of O3(BCFMgY) 0.4 Fe 0.4 Ni 0.1 Y 0.1 A proton-conductive ceramic fuel cell B was obtained in the same manner as in Example 1, except that O3(BCFNiY) was used.

[0123] <Performance evaluation of proton-conducting ceramic fuel cells> The same procedure as in Example 1 was carried out except that the proton conductive ceramic fuel cell B was used as the evaluation object instead of the proton conductive ceramic fuel cell A, and the maximum power density (MPD) and electrode resistance (R p The results are shown in Table 1.

[0124] Example 3 (1) Synthesis of battery materials <BaCo 0.4 Fe 0.4 Zn 0.1 Y 0.1 Synthesis of O3(BCFZnY) The target composition is BaCo 0.4 Fe 0.4 Zn 0.1 Y 0.1 BaCO3 (99.95%), Co(NO3)2·6H2O (99.9%), Fe(NO3)3·9H2O (99.9%), ZnO (99.9%), and Y(NO3)3·6H2O (99.9%) were weighed as the O3. Each was placed in a beaker and ion-exchanged water was added. The mixture was then dissolved by stirring using a hot stirrer. Citric acid (99.5%) and ethylene glycol (99.5%) were then added to form a precursor solution. The temperature of this precursor solution was gradually increased to 450°C and calcined at this temperature for approximately 2 hours to obtain a gel. The gel was crushed and decarbonized by holding it at 650°C for 10 hours, followed by calcination at 900°C for 10 hours. The calcined powder was crushed in a mortar and then wet ball milled for approximately 17 hours. The powder was then dried using a rotary evaporator (Tokyo Rikakikai, N-1110). This dried powder was mixed in a mortar and granulated by passing it through a sieve with 100 μm openings. This granulated powder was filled into a mold and uniaxially pressed at 200 MPa, followed by cold isostatic pressing (CIP) at 300 MPa to produce a pellet-shaped compact. This was then sintered at 1200°C for 10 hours to obtain a sintered body. The heating rate was 3°C / min. The obtained sintered body was crushed in a mortar, then subjected to a wet ball mill treatment, and the powder was dried using a rotary evaporator. This dried powder was obtained as an air electrode material and used in the air electrode. The obtained sintered body was also used to measure the oxygen transmission rate (JO2 ), total conductivity (σ t The results are shown in Table 1.

[0125] (2) Fabrication of proton-conducting ceramic fuel cells BaCo as the cathode material 0.4 Fe 0.4 Mg 0.1 Y 0.1 BaCo instead of O3(BCFMgY) 0.4 Fe 0.4 Zn 0.1 Y 0.1 A proton-conductive ceramic fuel cell C was obtained in the same manner as in Example 1, except that O3(BCFZnY) was used.

[0126] <Performance evaluation of proton-conducting ceramic fuel cells> The same procedure as in Example 1 was carried out except that the proton conductive ceramic fuel cell C was used as the evaluation object instead of the proton conductive ceramic fuel cell A, and the maximum power density (MPD) and electrode resistance (R p The results are shown in Table 1.

[0127] Example 4 (1) Synthesis of battery materials <BaCo 0.4 Fe 0.4 Ti 0.1 Y 0.1 Synthesis of O3(BCFTiY) The target composition is BaCo 0.4 Fe 0.4 Y 0.1 BaCO3 (99.95%), Co(NO3)2·6H2O (99.9%), Fe(NO3)3·9H2O (99.9%), and Y(NO3)3·6H2O (99.9%) were weighed as the O3. Each was placed in a beaker and ion-exchanged water was added, followed by dissolution while stirring using a hot stirrer. Citric acid (99.5%) and ethylene glycol (99.5%) were then added to form a precursor solution. The temperature of this precursor solution was gradually increased to 450°C and baked at this temperature for approximately 2 hours to obtain a gel. This gel was crushed and the composition was confirmed to be BaCo 0.4 Fe 0.4 Ti0.1 Y 0.1 After adding TiO2 (99.9%) to form O3, the mixture was decarbonized by holding it at 650°C for 10 hours and then calcined at 900°C for 10 hours. The calcined powder was pulverized in a mortar and subjected to a wet ball mill for approximately 17 hours. The powder was then dried using a rotary evaporator (Tokyo Rikakikai, N-1110). The dried powder was mixed in a mortar and granulated by passing it through a 100 μm mesh sieve. The granulated powder was filled into a mold and uniaxially pressed at 200 MPa, followed by cold isostatic pressing (CIP) at 300 MPa to produce pellets. The mixture was then sintered at 1200°C for 10 hours to obtain a sintered body. The heating rate was 3°C / min. The resulting sintered body was pulverized in a mortar, subjected to a wet ball mill, and then dried using a rotary evaporator. This dried powder was used as air electrode material. The obtained sintered body was used to measure the oxygen permeation rate (J O2 ), total conductivity (σ t The results are shown in Table 1.

[0128] (2) Fabrication of proton-conducting ceramic fuel cells BaCo as the cathode material 0.4 Fe 0.4 Mg 0.1 Y 0.1 BaCo instead of O3(BCFMgY) 0.4 Fe 0.4 Ti 0.1 Y 0.1 A proton-conducting ceramic fuel cell D was obtained in the same manner as in Example 1, except that O3(BCFTiY) was used.

[0129] <Performance evaluation of proton-conducting ceramic fuel cells> The same procedure as in Example 1 was carried out except that the proton conductive ceramic fuel cell D was used as the evaluation object instead of the proton conductive ceramic fuel cell A, and the maximum power density (MPD) and electrode resistance (R p The results are shown in Table 1.

[0130] (Comparative Example 1) (1) Synthesis of battery materials <BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 Synthesis of O3(BCFZrY) The target composition is BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 BaCO3 (99.95%), Co(NO3)2·6H2O (99.9%), Fe(NO3)3·9H2O (99.9%), ZrO(NO3)2·2H2O (99.0%), and Y(NO3)3·6H2O (99.9%) were weighed as the O3. Each was placed in a beaker and ion-exchanged water was added, followed by dissolution while stirring using a hot stirrer. Citric acid (99.5%) and ethylene glycol (99.5%) were then added to form a precursor solution. The temperature of this precursor solution was gradually increased to 450°C and calcined at this temperature for approximately 2 hours to obtain a gel. This gel was crushed, decarbonized by holding it at 650°C for 10 hours, and then calcined at 900°C for 10 hours. The calcined powder was crushed in a mortar and wet ball milled for approximately 17 hours. The powder was then dried using a rotary evaporator (Tokyo Rikakikai, N-1110). The dried powder was mixed in a mortar and granulated by passing it through a 100 μm mesh sieve. The granulated powder was filled into a mold and uniaxially pressed at 200 MPa, followed by cold isostatic pressing (CIP) at 300 MPa to produce a pellet-shaped compact. The sintered body was then sintered at 1200°C for 10 hours. The heating rate was 3°C / min. The sintered body obtained was crushed in a mortar, then subjected to a wet ball mill treatment, and the powder was dried using a rotary evaporator. The dried powder was obtained as an air electrode material and used in the air electrode. The resulting sintered body was also used to measure the oxygen transmission rate (J O2 ), total conductivity (σ t The results are shown in Table 1.

[0131] (2) Fabrication of proton-conducting ceramic fuel cells BaCo as the cathode material 0.4 Fe 0.4 Mg 0.1 Y 0.1 BaCo instead of O3(BCFMgY) 0.4Fe 0.4 Zr 0.1 Y 0.1 A proton-conducting ceramic fuel cell R was obtained in the same manner as in Example 1, except that O3(BCFZrY) was used.

[0132] <Performance evaluation of proton-conducting ceramic fuel cells> The same procedure as in Example 1 was carried out except that the proton conductive ceramic fuel cell R was used as the evaluation object instead of the proton conductive ceramic fuel cell A, and the maximum power density (MPD) and electrode resistance (R p The results at 600°C are shown in Table 1.

[0133] [Table 1]

[0134] The proton-conductive ceramic fuel cells of Examples 1, 2, 3, and 4 had higher maximum power densities than the proton-conductive ceramic fuel cell of Comparative Example 1. Among the materials evaluated this time, Table 1 shows that in terms of maximum power density, BCFMgY, followed by BCFNiY, then BCFZnY, and then BCFTiY, were highly effective as air electrodes for proton-conductive ceramic fuel cells. Furthermore, the proton-conductive ceramic fuel cells of Examples 1, 2, 3, and 4 had lower electrode resistance than the proton-conductive ceramic fuel cell of Comparative Example 1. Among the materials evaluated this time, Table 1 shows that, in terms of electrode resistance, BCFMgY, followed by BCFNiY, then BCFTiY, and then BCFZnY, were highly effective as air electrodes for proton-conductive ceramic fuel cells. Considering both the maximum power density and the electrode resistance, the proton-conducting ceramic fuel cells of Examples 1, 2, 3, and 4 have higher maximum power density and lower electrode resistance than the proton-conducting ceramic fuel cell of Comparative Example 1, and therefore have superior cell performance. [Industrial Applicability]

[0135] By using the present invention, it is possible to manufacture a proton-conducting ceramic fuel cell that has a high power density and a low reaction resistance of the air electrode, and therefore has high power generation performance.

Claims

1. The following general formula (1): Ba ｘ１ Co α１ Fe β１ MM γ１ M δ１ O ３－ｙ１ (1) (In formula (1), M is at least one of Ti, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x1 is 0.90 to 1.10; α1 is greater than 0.00 and less than or equal to 1.00; β1 is greater than 0.00 and less than or equal to 1.00; γ1 is greater than 0.00 and less than or equal to 0.30; δ1 is greater than 0.00 and less than or equal to 0.30; and y1 is 0.00 to 0.80.) 1. A proton-conducting ceramic fuel cell air electrode material, comprising a perovskite-type composite oxide represented by the formula:

2. The following general formula (2): Ba ｘ２ Co α２ Fe β２ Ni γ２ M δ２ O ３－ｙ２ (2) (In formula (2), M is at least one of Mg, Ti, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x2 is 0.90 to 1.10; α2 is greater than 0.00 and less than or equal to 1.00; β2 is greater than 0.00 and less than or equal to 1.00; γ2 is greater than 0.00 and less than or equal to 0.30; δ2 is greater than 0.00 and less than or equal to 0.30; and y2 is 0.00 to 0.80.) 1. A proton-conducting ceramic fuel cell air electrode material, comprising a perovskite-type composite oxide represented by the formula:

3. The following general formula (3): Ba ｘ３ Co α３ Fe β３ Zn γ３ M δ３ O ３－ｙ３ (3) (In formula (3), M is at least one of Mg, Ti, Ni, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x3 is 0.90 to 1.10; α3 is greater than 0.00 and less than or equal to 1.00; β3 is greater than 0.00 and less than or equal to 1.00; γ3 is greater than 0.00 and less than or equal to 0.30; δ3 is greater than 0.00 and less than or equal to 0.30; and y3 is 0.00 to 0.80.) 1. A proton-conducting ceramic fuel cell air electrode material, comprising a perovskite-type composite oxide represented by the formula:

4. The following general formula (4): Ba ｘ４ Co α４ Fe β４ Ti γ４ M δ４ O ３－ｙ４ (4) (In formula (4), M is at least one of Mg, Ni, Zn, Y, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Sc, and Ga; x4 is 0.90 to 1.10; α4 is more than 0.00 and not more than 1.00; β4 is more than 0.00 and not more than 1.00; γ4 is more than 0.00 and not more than 0.30; δ4 is more than 0.00 and not more than 0.30; and y4 is 0.00 to 0.80.) 1. A proton-conducting ceramic fuel cell air electrode material, comprising a perovskite-type composite oxide represented by the formula:

5. 2. A proton-conductive ceramic fuel cell air electrode comprising 30.0 mass % or more of the proton-conductive ceramic fuel cell air electrode material according to claim 1.

6. 3. A proton-conductive ceramic fuel cell air electrode comprising 30.0 mass % or more of the proton-conductive ceramic fuel cell air electrode material according to claim 2.

7. 4. A proton-conductive ceramic fuel cell air electrode comprising 30.0 mass % or more of the proton-conductive ceramic fuel cell air electrode material according to claim 3.

8. 5. A proton-conductive ceramic fuel cell air electrode comprising 30.0 mass % or more of the proton-conductive ceramic fuel cell air electrode material according to claim 4.

9. The cathode, the electrolyte, and the anode are formed in this order; The air electrode is a proton-conducting ceramic fuel cell air electrode according to any one of claims 5 to 8, The electrolyte is represented by the following general formula (6): No ｘ６ (Zr) α６ Yes β６ B6 （１－α６－β６） ) ｙ６ Oh ３＋ｚ６ (6) (In formula (6), B6 ​​is at least one of Sc, Ga, Y, In, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf, x6 is 0.80 to 1.20, α6 is 0.10 to 0.90, β6 is 0.00 to 0.10, y6 is 0.80 to 1.20, and z6 is −0.80 to +0.80.) The perovskite-type proton-conducting oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conducting oxide represented by the formula (I), A proton-conducting ceramic fuel cell comprising:

10. The cathode, the intermediate layer, the electrolyte, and the anode are formed in this order, The air electrode is a proton-conducting ceramic fuel cell air electrode according to any one of claims 5 to 8, The electrolyte is represented by the following general formula (6): No ｘ６ (Zr) α６ Yes β６ B6 （１－α６－β６） ) ｙ６ O ３＋ｚ６ (6) (In formula (6), B6 ​​is at least one of Sc, Ga, Y, In, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf, x6 is 0.80 to 1.20, α6 is 0.10 to 0.90, β6 is 0.00 to 0.10, y6 is 0.80 to 1.20, and z6 is −0.80 to +0.80.) The perovskite-type proton-conducting oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conducting oxide represented by the formula (I), The intermediate layer is formed of a compound represented by the following general formula (7): <h2 style=";text-align:left;direction:ltr">A7<h2 style=";text-align:left;direction:ltr"> ｘ７ <h2 style=";text-align:left;direction:ltr"> B7<h2 style=";text-align:left;direction:ltr"> ｙ７ <h2 style=";text-align:left;direction:ltr"> O<h2 style=";text-align:left;direction:ltr"> ３＋ｚ７ <h2 style=";text-align:left;direction:ltr"> ((7) (In formula (7), A7 is at least one of Ca, Sr, Ba, and La; B7 is at least one of Sc, Ga, Y, Zr, In, Ce, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Hf; x7 is 0.80 to 1.20; y7 is 0.80 to 1.20; and z7 is −0.80 to +0.80.) The perovskite-type proton-conducting oxide represented by the formula (I) contains 80.0 mass % or more of the perovskite-type proton-conducting oxide represented by the formula (I), A proton-conducting ceramic fuel cell comprising:

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