JPH11214014A - Air electrode of solid oxide fuel cell and method of manufacturing the same - Google Patents

Abstract

(57) [Object] To provide an air electrode of a solid oxide fuel cell having small polarization even at a low temperature and high long-term stability. SOLUTION: In the method for producing an air electrode of a solid oxide fuel cell, (A _{1 -xB x} ) (C _{1 -y} D _y ) O _{(3 +} δ ₎
An oxide powder having the following composition, a raw material containing the element E and a raw material containing Ce are added thereto, mixed and fired to obtain (A _1-x B _x ) (C _1-y D _y ) O _{(3+ [delta])} fine particles of a particle and CeO ₂ type of _{Ce 1-X E X O (} 2- δ) were mixed well dispersible form an air _{electrode, Ce 1-X E X O} (2-
δ ₎ is contained in the range of 0.5 to 50 wt%, A is La,
Any one or a combination of two or more of Y, Sm, Gd, Pr, and Ca; a combination of any one or two or more of Sr, Ba, and Ca; and a combination of Mn, Co, and Ce 1
One or a combination of two or more, D is Cr, Ni, Mg, Z
any one or a combination of two or more of r, Ce, Fe, Al, and E is Ca, Y, Sm, Gd, La, Mg, Sc,
Nd, Yb, Pr, Pb, Sr, Eu, Dy, Ba, B
e is one or a combination of two or more, and 0 ≦ x
≦ 0.50, 0 ≦ y ≦ 0.50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an air electrode of a solid oxide fuel cell and a method for producing the same.

[0002]

2. Description of the Related Art Fuel cells are drawing attention as an energy source not only from the viewpoint of resource saving but also from the viewpoint of environmental impact.

[0003] A solid oxide fuel cell (SOFC) is a cell in which a fuel electrode is arranged on one side of a solid electrolyte layer and an air electrode is arranged on the other side, and adjacent cells are electrically connected in series. The fuel cell and the separator for distributing the oxidizing gas are alternately stacked in a unit cell to form a multi-layer stack.
Since the temperature is as high as 1000 ° C., the power generation efficiency is high, and since the constituent materials are all solid, there are advantages such as easy handling, and practical use is progressing.

In a single cell (cell) of a solid oxide fuel cell, a fuel electrode is first placed on one side of a central solid electrolyte layer.
The electrode is fired at a high temperature of about 0 ° C., and then the air electrode is fired at a low temperature of about 1150 ° C. on the opposite surface, and each of these electrodes has an interface with the solid electrolyte layer. For the solid electrolyte, 8YSZ (YSZ is stabilized zirconia doped with yttria) or 3YSZ is mainly used.

As an air electrode material, LaSrMnO ₃ (L
SM) are known as typical ones. In addition, La in the LSM is replaced with another element,
A Co-based material in which Mn is replaced with Co has also been proposed.

[0006]

Conventionally, LSM has sufficient performance at an operating temperature of 1000 ° C., but the surface diffusion of adsorbed oxygen is slowed down as the operating temperature is lowered, and the polarization is considerably increased. was there. In addition, the Co type has a large reactivity with the electrolyte and has a problem in long-term stability.

[0007] The present invention has been made in view of the above points, and has as its object to provide an air electrode of a solid oxide fuel cell having small polarization even at a low temperature and high long-term stability. .

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a method for manufacturing an air electrode of a solid oxide fuel cell, comprising the steps of: (A _{1 -xB x} ) (C _{1 -y} D _y ) O An oxide powder having a composition of _{(3 +} δ ₎ , a raw material containing the element E and a raw material containing Ce are added thereto, mixed, and fired to obtain (A _1−x B _x ) (C _{1 -y D y) O (3+ δ} ) particles of particles and the CeO ₂ type _{Ce 1-X E X O (} 2- δ) were mixed well dispersible form an air electrode, Ce _1-X E X O _(2-
δ ₎ is contained in the range of 0.5 to 50 wt%, where A is any one or a combination of two or more of La, Y, Sm, Gd, Pr, and Ca, and B is Sr, Ba, and Ca. Any one
One or a combination of two or more, C is any one or a combination of two or more of Mn, Co, Ce, and D is Cr, Ni, M
g, Zr, Ce, Fe, or any one or a combination of two or more of Al, E is Ca, Y, Sm, Gd, La, Mg,
Sc, Nd, Yb, Pr, Pb, Sr, Eu, Dy, B
a, Be or a combination of two or more of Be,
It is characterized in that 0 ≦ x ≦ 0.50 and 0 ≦ y ≦ 0.50.

In the present invention, A is La and B is Sr
Wherein C is Mn and E is Sm or Gd.
It is characterized by the following.

Further, the present invention is characterized in that A is Pr, B is Sr, C is Mn, and E is Sm or Gd.

Further, the present invention is characterized in that A is Ca, B is Ce, C is Mn, and E is Sm or Gd.

Further, the present invention is characterized in that A is La, B is Sr, C is Co, and E is Sm or Gd.

Further, the present invention is characterized in that A is Sm, B is Sr, C is Co, and E is Sm or Gd.

Further, the present invention is characterized in that the starting material of _{Ce 1-X E X O (} 2- δ) is a metal organic compound of Ce or E.

Further, the present invention is characterized in that the metal organic compound is one or a combination of two or more of octylate, naphthenate and acetylacetonate complex.

Further, the present invention is A is Pr, B is Sr, C is Mn, E is Sm or _{Gd, Ce 1-X E X} O (2-
The starting material of δ ₎ is an octylate of Ce and E.

Further, the present invention is wherein A is Ca, B is Ce, C is Mn, E is Sm or _{Gd, Ce 1-X E X} O (2-
The starting material of δ ₎ is an octylate of Ce and E.

Further, the present invention A is La, B is Sr, a C is Co, E is Sm or _{Gd, Ce 1-X E X} O (2-
The starting material of δ ₎ is an octylate of Ce and E.

Further, the present invention is A is Sm, B is Sr, C is Co, E is Sm or _{Gd, Ce 1-X E X} O (2-
The starting material of δ ₎ is an octylate of Ce and E.

Further, the present invention relates to a method for producing an air electrode of a solid oxide fuel cell, wherein (A _{1 -xB x} ) (C _{1 -y} D
_y ) A powder of an oxide having a composition of O ₍₃₊ δ ₎ and a solution of a metal organic compound of E and Ce are added thereto to form a slurry, and E and Ce are hydrolyzed in the slurry, After the polycondensation reaction further proceeds, it is applied on the electrolyte, heat is applied to perform a thermal decomposition reaction, and the mixture is fired at a high temperature to obtain (A _1-x B _x ) (C _1-y D _y ) O
_{(3+ [delta])} fine particles of a particle and _{Ce 1-X E X O (} 2- δ) by mixing well dispersible form an air _{electrode, Ce 1-X E X O} (2-
δ ₎ is contained in the range of 0.5 to 50 wt%, where A is any one or a combination of two or more of La, Y, Sm, Gd, Pr, and Ca, and B is Sr, Ba, and Ca. Any one
One or a combination of two or more, C is any one or a combination of two or more of Mn, Co, Ce, and D is Cr, Ni, M
g, Zr, Ce, Fe, or any one or a combination of two or more of Al, E is Ca, Y, Sm, Gd, La, Mg,
Sc, Nd, Yb, Pr, Pb, Sr, Eu, Dy, B
a, Be or a combination of two or more of Be,
It is characterized in that 0 ≦ x ≦ 0.50 and 0 ≦ y ≦ 0.50.

In the present invention, the average particle diameter is in the range of 1 to 10 μm, and (A ₁ -xB _x ) (C _{1 -y} D _y ) O _{(3 +} δ ₎
And the average particle size of the particles surrounding the particles is in the range of 0.1 to 2 μm, and Ce _1-X E
Consists of a particle having a composition of _X O _{(2- δ),} in the range porosity of 20-50%, in the range _{Ce 1-X E X O (} 2- δ) is 0.5～50Wt% Included, where A is L
any one or two of a, Y, Sm, Gd, Pr, Ca
One or more combinations, B is any one or two or more combinations of Sr, Ba, Ca, C is any one or two or more combinations of Mn, Co, Ce, D is Cr, Ni, Mg ,
Any one or a combination of two or more of Zr, Ce, Fe, and Al, and E is Ca, Y, Sm, Gd, La, Mg, S
c, Nd, Yb, Pr, Pb, Sr, Eu, Dy, B
a, Be or a combination of two or more of Be,
A solid oxide fuel cell, wherein 0 ≦ x ≦ 0.50 and 0 ≦ y ≦ 0.50 is provided.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

The outline of the method for manufacturing the air electrode of the solid oxide fuel cell according to the present invention is as follows: (A _{1 -xB x} ) (C _{1 -y} D _y )
An oxide powder having a composition of O ₍₃₊ δ ₎ , a raw material containing the element E and a raw material containing Ce are added thereto, mixed, and fired to obtain (A _1−x B _x ) (C _1-y D _y ) O
_{(3+ [delta])} fine particles are well mixed dispersion of the particles and the CeO ₂ type of _{Ce 1-X E X O (} 2- δ) to form an air electrode, Ce
_1-X E _X O a _(2-[delta]) included in the range of 0.5~50wt%, where A is one of La, Y, Sm, Gd, Pr, Ca or a combination of two or more , B is Sr, Ba, C
a is one or a combination of two or more, C is Mn, C
any one or a combination of two or more of o and Ce, and D is C
any one of r, Ni, Mg, Zr, Ce, Fe, and Al
One or a combination of two or more, E is Ca, Y, Sm, Gd,
La, Mg, Sc, Nd, Yb, Pr, Pb, Sr, E
u, Dy, Ba, Be, or a combination of two or more of 0, x ≦ 0.50, 0 ≦ y ≦ 0.50
It is. Incidentally, in the present specification, _{(3 +} δ ₎ in the composition formula
And _(2- δ ₎ indicate the amount of oxygen.

Thus, (A _1−x B _x ) (C _1−y D _y )
O 0 microparticles of _{(3+ [delta])} of the perovskite material yet CeO ₂ type Ce _1-X E X O as a base _{(2- δ).}
By forming the air electrode dispersible well mixed in a range of _{5~50wt%, Ce 1-X E} X O (2- δ) 0.5
An air electrode having good low-temperature activity was prepared by including the content in the range of ５０50 wt%.

(A _1-x B _x ) (C _1-y D _y ) O ₍₃₊ δ ₎
It has been clarified that a desired microstructure and a desired performance can be obtained by using powder and metal salts of Ce and Sm as raw materials, and particularly using a metal organic compound as the metal salt.

[0026]

Embodiment 1 FIG. 1 is a flow chart for explaining Embodiment 1 of a method for manufacturing an air electrode according to the present invention.

Of the raw material powder of the above-mentioned cathode material, manganese oxide was calcined at 800 ° C. for 10 hours,
After cooling to room temperature, the mixture was quenched to room temperature,
n ₂ O ₃ powder, this Mn ₂ O ₃ powder mixed with Pr ₂ O ₃ powder and Sr ₂ CO ₃ powder to form a mixed powder, press-molded this mixed powder, and calcined at 1300 ° C. for 10 hours. Then crush this. This was calcined again at 1300 ° C. for 10 hours, pulverized, and further classified to obtain Pr _0.8 Sr of 2-3 μm.
_0.2 MnO ₃ powder. This Pr _0.8 Sr _0.2 MnO ₃
Sm octylate and Ce octylate are added to the powder to form a mixed slurry. Next, the mixed slurry is hydrolyzed, polycondensed and screen-printed on the electrolyte,
Further, it is thermally decomposed at 500 ° C., calcined at 1150 ° C., and Mn
Pr _0.8 Sr _0.2 MnO ₃ based on a base material and C
Fine particles of eO ₂ -based Ce _0.8 Sm _O.2 O _1.9 were mixed with good dispersibility to form an air electrode.

[0028]

Embodiment 2 FIG. 2 is a flow chart for explaining Embodiment 2 of the method for producing an air electrode according to the present invention.

The process from the above-mentioned air electrode material to Mn ₂ O ₃ powder is the same as that of the first embodiment. This Mn ₂
The O ₃ powder by mixing CeO ₂ powder and CaO powder is mixed powder, 1 This mixed powder was press-molded, it at 1300 ° C.
This is calcined for 0 hour and ground. This was calcined again at 1300 ° C. for 10 hours, pulverized, and further classified to 2-3 μm.
m _0.8 Ca _0.8 Ce _0.2 MnO ₃ powder. This Ca _0.8
Sm octylate and Ce octylate are added to Ce _0.2 MnO ₃ powder to form a mixed slurry. Next, the mixed slurry was hydrolyzed, polycondensed, and screen-printed on the electrolyte.
Sintering at 0 ° C, Ca _0.8 Ce based on Mn-based material
_0.2 MnO ₃ and CeO ₂ -based Ce _{0.8 Sm.2} O _1.9
Were mixed with good dispersibility to form an air electrode.

[0030]

Comparative Example 1 Pr _0.8 Sr _0.2 MnO ₃ powder (A) in FIG. 1 was screen-printed and fired at 1150 ° C.

[0031]

COMPARATIVE EXAMPLE 2 The Ca _0.8 Ce _0.2 MnO ₃ powder (B) in FIG. 2 was screen-printed and fired at 1150 ° C.

[0032]

Comparative Example 3 La _0.85 Sr _0.15 MnO ₃ powder was screen-printed and fired at 1150 ° C.

FIG. 3 is a comparison table of durability data between the air electrode manufactured by the method of the present invention and the air electrode manufactured by the conventional method.

From FIG. 3, it can be seen that the air electrode manufactured according to the present invention does not show performance deterioration (increase in polarization) due to long-time operation, and is superior in durability compared with the comparative example of the conventional method.

FIG. 4 is a graph illustrating the performance of an air electrode fired at a high temperature by the method of the present invention in comparison with the performance of an air electrode fired at a low temperature by the conventional method.

The current density is represented by log (I / Acm ⁻² ) on the horizontal axis.
, And the vertical axis indicates the magnitude of the polarization in mv.

Comparative Example 3 is a conventional LSM electrode, whereas Examples 1 and 2 are excellent air electrodes with small polarization.

In Example 1, the Pr _0.8 Sr of Comparative Example 1 was used.
Applying the present invention to _0.2 MnO ₃ , Pr _0.8 Sr
This was a mixed electrode of _0.2 MnO ₃ and SDC, and the electrode performance was improved by the method of the present invention.

Similarly, in Example 2, the Ca _0.8 Ce of Comparative Example 2 was used.
_The present invention is applied to _0.2 MnO ₃ and Ca _0.8 Ce
This was a mixed electrode of _0.2 MnO ₃ and SDC, and the application of the present invention improved the electrode performance and reduced the polarization.

FIG. 5 is a micrograph of the particle structure of the air electrode manufactured by the method of the present invention, and FIG. 6 is a micrograph of the particle structure of the air electrode manufactured by the conventional method.

By comparing FIGS. 5 and 6, it is found that the air electrode structure according to the present invention has a 1 μm
It can be seen that some CeO ₂ -based material is surrounding.
Therefore, the air electrode according to the present invention has a property that polarization is small even at a low temperature and high long-term stability.

[0042]

(1) According to the micrograph, the particle structure of the air electrode of the present invention is 1 μm around the 3-4 μm Mn-based material.
It was found that about m of CeO ₂ -based material was surrounded. (2) The air electrode according to the present invention has a property that polarization is small even at a low temperature and high long-term stability.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating Example 1 of an air electrode manufacturing method according to the present invention.

FIG. 2 is a flowchart for explaining a second embodiment of the air electrode manufacturing method according to the present invention.

FIG. 3 is a comparison table of durability data between an air electrode manufactured by the method of the present invention and an air electrode manufactured by a conventional method.

FIG. 4 is a graph showing a part of FIG. 3;

FIG. 5 is a micrograph of a particle structure of an air electrode prepared by the method of the present invention.

FIG. 6 is a micrograph of a particle structure of an air electrode produced by a conventional method.

Claims (30)

[Claims] 1. A method for producing an air electrode of a solid oxide fuel cell, comprising: an oxide powder having a composition of (A _1-x B _x ) (C _1-y D _y ) O ₍₃₊ δ ₎ ; Then, a raw material containing the element E and a raw material containing Ce are added thereto, mixed, and fired to obtain (A _{1 -xB x} ) (C _{1 -y} D _y ) O _{(3 +} δ ₎ particles and CeO _2. the fine particles of the system of _{Ce 1-X E X O (} 2- δ) dispersible well mixed to form an air _{electrode, Ce 1-X E X O} (2-
δ ₎ is included in the range of 0.5 to 50% by weight, wherein A is any one or a combination of two or more of La, Y, Sm, Gd, Pr, and Ca, and B is Sr, Ba, and Ca. Any one or a combination of two or more, C is Mn, Co,
Ce is one or a combination of two or more, D is Cr,
Any one or a combination of two or more of Ni, Mg, Zr, Ce, Fe, and Al, E is Ca, Y, Sm, Gd, L
a, Mg, Sc, Nd, Yb, Pr, Pb, Sr, E
u, Dy, Ba, Be, or a combination of two or more of 0, x ≦ 0.50, 0 ≦ y ≦ 0.50
A method for producing an air electrode of a solid oxide fuel cell, characterized in that: 2. A is La, B is Sr, and C is M
The method for producing an air electrode of a solid oxide fuel cell according to claim 1, wherein n is E and S is Sm or Gd. 3. A is Pr, B is Sr, C is Mn, and E is Sm.
The method for producing an air electrode of a solid oxide fuel cell according to claim 1, wherein the air electrode is Gd. 4. A is Ca, B is Ce, C is Mn, and E is Sm.
The method for producing an air electrode of a solid oxide fuel cell according to claim 1, wherein the air electrode is Gd. 5. A is La, B is Sr, C is Co, and E is Sm.
The method for producing an air electrode of a solid oxide fuel cell according to claim 1, wherein the air electrode is Gd. 6. A is Sm, B is Sr, C is Co, and E is Sm.
The method for producing an air electrode of a solid oxide fuel cell according to claim 1, wherein the air electrode is Gd. 7. Ce _1-X E X O starting material _(2-[delta]) is Ce
And a metal organic compound of E and E.
3. The method for producing an air electrode of a solid oxide fuel cell according to item 1. 8. The solid electrolyte fuel according to claim 1, wherein the metal organic compound is any one or a combination of two or more of an octylate, a naphthenate and an acetylacetonate complex. How to make a battery air electrode. 9. A is Pr, B is Sr, C is Mn, and E is Sm.
Or a _{Gd, Ce 1-X E X} O (2- δ) starting material of the air electrode of the solid oxide fuel cell according to claim 1, characterized in that the octylate salt of Ce and E Production method. 10. A is Ca, B is Ce, C is Mn, and E is S
is m or _{Gd, Ce 1-X E X} O (2- δ) solid oxide fuel cell air electrode according to claim 1, the starting material is characterized in that it is a octylate salt of Ce and E Method of manufacturing. 11. A is La, B is Sr, C is Co, E is S
is m or _{Gd, Ce 1-X E X} O (2- δ) solid oxide fuel cell air electrode according to claim 1, the starting material is characterized in that it is a octylate salt of Ce and E Method of manufacturing. 12. A is Sm, B is Sr, C is Co, E is S
is m or _{Gd, Ce 1-X E X} (2- δ) starting material of the air electrode of the solid oxide fuel cell according to claim 1, characterized in that the octylate salt of Ce and E Production method. 13. A method for manufacturing an air electrode of a solid oxide fuel cell, comprising: (A _{1 -xB x} ) (C _{1 -y} D _y ) O _{(3 +} δ ₎
An oxide powder having the following composition and a solution of a metal organic compound of E and Ce were added thereto to form a slurry, and E and Ce were hydrolyzed in the slurry to further advance the polycondensation reaction. Thereafter, the mixture is applied on an electrolyte, heat is applied to cause a thermal decomposition reaction, and the mixture is calcined at a high temperature to obtain (A _1-x B _x ) (C _1-y D _y ) O ₍₃₊ δ ₎ particles. _{Ce 1-X E X O (} 2- δ) microparticle dispersion with good by mixing of forming the air _{electrode, Ce 1-X E X O} (2- δ) is 0.5 and
Where A is any one or combination of two or more of La, Y, Sm, Gd, Pr, and Ca, and B is any one or two of Sr, Ba, and Ca The above combination, C is Mn, Co,
Ce is one or a combination of two or more, D is Cr,
Any one or a combination of two or more of Ni, Mg, Zr, Ce, Fe, and Al, E is Ca, Y, Sm, Gd, L
a, Mg, Sc, Nd, Yb, Pr, Pb, Sr, E
u, Dy, Ba, Be, or a combination of two or more of 0, x ≦ 0.50, 0 ≦ y ≦ 0.50
A method for producing an air electrode of a solid oxide fuel cell, characterized in that: 14. The air electrode of the solid oxide fuel cell according to claim 13, wherein A is La, B is Sr, C is Mn, and E is Sm or Gd. Method of manufacturing. 15. A is Pr, B is Sr, C is Mn, and E is S
The method for producing an air electrode of a solid oxide fuel cell according to claim 13, wherein m or Gd is used. 16. A is Ca, B is Ce, C is Mn, and E is S
The method for producing an air electrode of a solid oxide fuel cell according to claim 13, wherein m or Gd is used. 17. A is La, B is Sr, C is Co, E is S
The method for producing an air electrode of a solid oxide fuel cell according to claim 13, wherein m or Gd is used. 18. A is Sm, B is Sr, C is Co, E is S
The method for producing an air electrode of a solid oxide fuel cell according to claim 13, wherein m or Gd is used. Starting material 19. _{Ce 1-X E X O (} 2- δ) is C
14. The method for producing an air electrode of a solid oxide fuel cell according to claim 13, wherein the organic electrode is a metal organic compound of e and E. 20. The method according to claim 1, wherein the metal organic compound is any one or a combination of two or more of octylate, naphthenate and acetylacetonate complex.
4. The method for producing an air electrode of the solid oxide fuel cell according to 3. 21. A is Pr, B is Sr, C is Mn, and E is S
is m or _{Gd, Ce 1-X E X} O (2- δ) solid oxide fuel cell air electrode according to claim 13, the starting material is characterized in that it is a octylate salt of Ce and E Method of manufacturing. 22. A is Ca, B is Ce, C is Mn, and E is S
is m or _{Gd, Ce 1-X E X} O (2- δ) solid oxide fuel cell air electrode according to claim 13, the starting material is characterized in that it is a octylate salt of Ce and E Method of manufacturing. 23. A is La, B is Sr, C is Co, E is S
is m or _{Gd, Ce 1-X E X} O (2- δ) solid oxide fuel cell air electrode according to claim 13, the starting material is characterized in that it is a octylate salt of Ce and E Method of manufacturing. 24. A is Sm, B is Sr, C is Co, E is S
is m or _{Gd, Ce 1-X E X} O (2- δ) solid oxide fuel cell air electrode according to claim 13, the starting material is characterized in that it is a octylate salt of Ce and E Method of manufacturing. 25. An average particle diameter in a range of 1 to 10 μm,
Particles having a composition of (A _1-x B _x ) (C _1-y D _y ) O _{(3 +} δ ₎ and an average particle diameter in a state surrounding the particles are in the range of 0.1 to 2 μm. _{, Ce 1-X E X O} (2- δ)
Having a porosity of 20 to 50%.
In the range _{of, Ce 1-X E X O} (2- δ) 0.5 to 50
where A is any one or a combination of two or more of La, Y, Sm, Gd, Pr, and Ca, and B is Sr, Ba, Ca
C is Mn, C
any one or a combination of two or more of o and Ce, and D is C
any one of r, Ni, Mg, Zr, Ce, Fe, and Al
One or a combination of two or more, E is Ca, Y, Sm, Gd,
La, Mg, Sc, Nd, Yb, Pr, Pb, Sr, E
A solid electrolyte fuel cell, wherein any one or a combination of two or more of u, Dy, Ba, and Be is satisfied, and 0 ≦ x ≦ 0.50 and 0 ≦ y ≦ 0.50. 26. The solid oxide fuel cell according to claim 25, wherein A is La, B is Sr, C is Mn, and E is Sm or Gd. 27. A is Pr, B is Sr, C is Mn, and E is S
26. The solid oxide fuel cell according to claim 25, which is m or Gd. 28. A is Ca, B is Ce, C is Mn, and E is S
26. The solid oxide fuel cell according to claim 25, which is m or Gd. 29. A is La, B is Sr, C is Co, E is S
26. The solid oxide fuel cell according to claim 25, which is m or Gd. 30. A is Sm, B is Sr, C is Co, E is S
26. The solid oxide fuel cell according to claim 25, which is m or Gd.