JP2003217597A - Solid electrolyte type fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid electrolyte type fuel cell that improves electrode activity between a fuel electrode and an electrolyte and has excellent output performance. <P>SOLUTION: For the solid electrolyte type fuel cell comprising an air electrode, an electrolyte and a fuel electrode, and containing an electrode reaction layer interposed between the electrolyte and the fuel electrode, the electrode reaction layer contains a catalyst facilitating a reaction forming H<SB>2</SB>O and/or CO<SB>2</SB>and an electron from at least hydrogen gas (H<SB>2</SB>) and/or carbon monoxide gas (CO) contained in a fuel gas component and an oxygen ion (O<SP>2-</SP>) and has a communicating air hole. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a solid oxide fuel cell having excellent output performance. In particular, the present invention relates to a solid oxide fuel cell having excellent output performance even at an operating temperature of 700 to 900 ° C.

[0002]

2. Description of the Related Art Conventionally, zirconia in which yttria is solid-solved (hereinafter referred to as YSZ) is used as an electrolyte.
As a fuel electrode, it has high electronic conductivity, is stable in a fuel gas atmosphere, and has a thermal expansion coefficient close to that of YSZ.
A layer in which i or NiO and YSZ are uniformly mixed (hereinafter referred to as Ni / YSZ
Or shown as NiO / YSZ. ) Has been used. In order to enhance the electronic conductivity, a large proportion of Ni in Ni / YSZ or NiO / YSZ and a large particle size have been used to diffuse hydrogen gas and carbon monoxide gas. (For example, Non-Patent Document 1) There is also a proposal that a layer made of NiO / YSZ is interposed between an electrolyte and a fuel electrode of a solid oxide fuel cell. (For example, patent documents
1)

[0003]

[Non-Patent Document 1] Kazuo Fueki, Masao Takahashi [Fuel Cell Design Technology] Science Forum Publishing, September 30, 1987, P2
21-230

[Patent Document 1] Japanese Unexamined Patent Publication No. 9-73913 (pages 1 to 3, FIG. 1)

[0004]

Since the particle size is large, there is a problem that the adhesion to the electrolyte material is low and the output performance is reduced. Further, since the ratio of Ni is large, oxygen ions supplied from the electrolyte can cause the reaction of formulas (1) and (2) only at the interface between the electrolyte and the fuel electrode, which causes a problem that the output performance is deteriorated. there were. ^{_{H 2 + O 2- → H 2}} O + 2e - ... (1) CO + O 2- → CO 2 + 2e - ... (2)

In Patent Document 1, if the operating temperature is about 900 to 1000 ° C., the output performance of the cell is improved by providing the layer made of NiO / YSZ. However, when the operating temperature is 900 ° C. or lower, there is a problem that the electrode activity of these materials themselves is lowered, and the output performance of the solid oxide fuel cell is lowered.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a solid oxide fuel cell having improved electrode activity between a fuel electrode and an electrolyte and excellent output performance. .

[0007]

To achieve the above object, a first invention comprises an air electrode, an electrolyte and a fuel electrode, and an electrode reaction layer is interposed between the electrolyte and the fuel electrode. In the solid oxide fuel cell, the electrode reaction layer is at least hydrogen gas (H ₂ ) and / or carbon monoxide gas (CO) contained in the fuel gas component, and oxygen ions (O ^{2 −} ),
To H ₂ O and / or CO ₂ and a catalyst that promotes a reaction to generate electrons, and has open pores in communication with each other.

According to the present invention, since the electrode reaction layer is provided between the electrolyte and the fuel electrode, it is possible to provide a solid oxide fuel cell having excellent output performance.

The reason for this is that at least hydrogen gas (H ₂ ) and / or carbon monoxide gas (CO) contained in the fuel gas component in the electrode reaction layer, oxygen ions (O ²⁻ ) and H ₂ O and /
Alternatively, since it has a function of accelerating the reaction that produces electrons with CO ₂ , it is possible to efficiently proceed the reactions of formulas (1) and (2) that occur between the electrolyte and the fuel electrode, and improve the output performance. It is possible to diffuse hydrogen gas and carbon monoxide gas throughout the electrode reaction layer because it has open pores communicating with each other, the reaction of the formula (1), (2) in the entire electrode reaction layer. This is because it can be awakened. ^{_{H 2 + O 2- → H 2}} O + 2e - ... (1) CO + O 2- → CO 2 + 2e - ... (2)

It is reported that the reaction of the above formula (1) is strictly explained as a two-step reaction of the formulas (3) and (4). Here, Ni will be described as an example. O ^{2 −} + Ni → NiO + 2e ⁻ … (3) NiO + H ₂ → Ni + H ₂ O… (4) However, it is difficult to separate the above reaction exactly, so here the electrode reaction ( 3) + (4), that is, formula (1) is used for explanation.

Also, CH _{4 and the} like contained in the fuel gas are (1),
Although it is reported that there is a reaction that produces electrons similar to equation (2), most of the reactions in power generation of a solid oxide fuel cell can be explained by equations (1) and (2), so here (1), It was decided to explain using equation (2).

In order to achieve the above object, a second invention is
It is provided that the electrode reaction layer has a pore size of 0.1 to 5 μm.

According to the present invention, since the pore size of the electrode reaction layer is limited, the reaction of the formulas (1) and (2) can be efficiently proceeded, and a solid oxide fuel cell having excellent output performance is provided. be able to.

The reason for this is that if the pore size is smaller than 0.1 μm, there are almost no open pores communicating with each other in the electrode reaction layer, so that hydrogen gas and carbon monoxide gas cannot be diffused into the electrode reaction layer and the output performance deteriorates. On the other hand, when the pore size is larger than 5 μm, the number of contacts between the electrolyte and the electrode reaction layer is reduced, so that the adhesion is decreased, the contact resistance between the electrolyte and the electrode reaction layer is increased, and the output performance is decreased. .

The pore diameter shown here is obtained by the following method. SE of the cross section of the polished electrode reaction layer
Observe, take a picture, and transfer it to a transparent film. The size of the void is measured, and for example, the diameter of the void corresponding to a circle is the pore diameter, and the diameter of a square is the length of one side as the pore diameter.

The term "pore diameter of 0.1 to 5 μm" as used herein means that among 100 pore diameters measured by the above-mentioned method and measured in the range of 3 to 97 when arranged in ascending order of diameter. Five
It means that the 0-th pore size is 0.1 to 5 μm. That is, it means that the pore diameter in the range of 3% to 97% diameter, which corresponds to 50% diameter, is 0.1 to 5 μm.

In order to achieve the above object, a third invention is:
The pore size of the electrode reaction layer is smaller than the pore size of the fuel electrode.

According to the present invention, since the relationship between the electrode reaction layer and the pore size of the fuel electrode is limited, it is possible to provide a solid oxide fuel cell having excellent output performance.

The reason for this is that the pore size of the electrode reaction layer is smaller than the pore size of the fuel electrode, so that the adhesion with the electrolyte is improved as compared with the case where the fuel electrode and the electrolyte are laminated.
This is because the output performance is improved.

In order to achieve the above object, a fourth invention is
It is provided that the electrode reaction layer has a porosity of 3 to 40%.

According to the present invention, since the porosity of the electrode reaction layer is limited, the reaction of formulas (1) and (2) can be efficiently proceeded, and a solid oxide fuel cell having excellent output performance is provided. be able to.

The reason for this is that if the porosity is less than 3%, the number of open pores communicating with each other in the electrode reaction layer is too small, so that hydrogen gas and carbon monoxide gas cannot be efficiently diffused in the electrode reaction layer and the output is generated. On the other hand, if it is more than 40%, the contact between the electrolyte and the electrode reaction layer will decrease, so the adhesion will decrease, the contact resistance between the electrolyte and the electrode reaction layer will increase, and the output performance will decrease. is there.

The porosity shown here is obtained by the following method. Take a cross-sectional photograph of the electrode reaction layer portion polished by SEM, and trace the voids and particles on the transparent film in different colors. The color-coded films are subjected to image processing to calculate the ratio of voids.

In order to achieve the above object, a fifth invention is:
The porosity of the electrode reaction layer is provided to be equal to or lower than the porosity of the fuel electrode.

According to the present invention, since the relationship between the electrode reaction layer and the porosity of the fuel electrode is limited, it is possible to provide a solid oxide fuel cell having excellent output performance.

The reason for this is that the electrode reaction layer has a porosity equal to or lower than the porosity of the fuel electrode, so that the adhesion with the electrolyte is improved and the output performance is improved as compared with the case where the fuel electrode and the electrolyte are laminated. Is.

A sixth invention for achieving the above object is as follows:
It is provided that the particle size in the electrode reaction layer is 0.3 to 5 μm.

According to the present invention, since the particle size in the electrode reaction layer is limited, it is possible to efficiently proceed the reactions of formulas (1) and (2), and to provide a solid oxide fuel cell having excellent output performance. You can

The reason for this is that if the particle size is smaller than 0.3 μm, there are too few communicating open pores in the electrode reaction layer.
This is because hydrogen gas and carbon monoxide gas cannot be efficiently diffused in the electrode reaction layer, which lowers the output performance. On the other hand, when it is larger than 5 μm, the surface area of the particles becomes small, so that a catalyst for converting oxygen ions into electrons. This is because the performance is lowered and the output performance is lowered.

The particle size shown here is a particle size obtained by the following planimetric method. First, take a picture of the cross section of the electrode reaction layer with SEM, draw a circle of the area (A) on this picture, and calculate from the number of particles in the circle n _c and the number of particles on the circumference n _i
The number of particles N _G per unit area is calculated by the equation (5). N _G = (n _c + 1 / 2n _i ) / (A / m ² ) ... (5) m shown here is the magnification of the photograph. Since 1 / _NG is the area occupied by one particle, the diameter of the circle on the film surface is equivalent to 2 / √
(π N _G ), one side of the square gives 1 / √N _G.

The particle size of 0.3 to 5 μm shown here means that the particle size is measured at 100 points by the planimetric method and the particles are arranged in the order of decreasing particle size from the third to the 97th, and the 50th. The particle size is 0.3 to 5 μm. Ie 3
In the range of% diameter to 97% diameter, the particle diameter corresponding to 50% diameter is 0.
It means 3 to 5 μm.

In order to achieve the above object, the seventh invention is
It provides that the particle size in the electrode reaction layer is smaller than the particle size in the anode.

According to the present invention, since the relationship between the electrode reaction layer and the particle size of the fuel electrode is limited, it is possible to provide a solid oxide fuel cell having excellent output performance.

The reason for this is that the particle size in the electrode reaction layer is smaller than the particle size in the fuel electrode, so that the adhesion with the electrolyte is improved and the output performance is improved compared to the case where the fuel electrode and the electrolyte are laminated. is there.

In order to achieve the above object, an eighth invention is
It is provided that the thickness of the electrode reaction layer is 3 to 50 μm.

According to the present invention, since the thickness of the electrode reaction layer is limited, the reaction of the formulas (1) and (2) can be efficiently proceeded, and a solid oxide fuel cell having excellent output performance can be provided. it can.

The reason for this is that if the thickness of the electrode reaction layer is smaller than 3 μm, the reaction performance in which the reaction of the equations (1) and (2) can be performed is reduced, and the output performance deteriorates. This is because the gas and carbon monoxide gas cannot be efficiently diffused in the electrode reaction layer, so that the output performance is deteriorated.

In order to achieve the above object, a ninth invention is:
The thickness of the electrode reaction layer is smaller than that of the fuel electrode.

According to the present invention, since the relationship between the electrode reaction layer and the thickness of the fuel electrode is limited, it is possible to provide a solid oxide fuel cell having excellent output performance.

The reason for this is that if the electrode reaction layer is thicker than the fuel electrode, the reactions of formulas (1) and (2) cannot proceed efficiently.

The tenth invention for achieving the above object is as follows:
The electrode reaction layer has at least oxygen ion conductivity of 1000 ° C.
Provide that the material contains 0.1Scm ^-1 or more.

According to the present invention, at least the material having high oxygen ion conductivity is contained in the electrode reaction layer, so that the reaction of the formulas (1) and (2) can be carried out rapidly.

The reason for this is that oxygen ions supplied from the electrolyte can be efficiently diffused into the electrode reaction layer,
This is because the reactions of the formulas (1) and (2) can be carried out in the entire electrode reaction layer. It is preferable that the oxygen ion conductivity is 0.1 Scm ⁻¹ or more at 1000 ° C. because it is possible to have sufficient output performance even at a low temperature of about 700 ° C.

To achieve the above object, the eleventh invention provides that the electrode reaction layer contains at least Ni.

According to the present invention, at least the electrode reaction layer comprises
Since it contains Ni, it has high electronic conductivity, and the reactions of formulas (1) and (2) can be carried out rapidly.

The reason for this is that the electrons generated by the reactions of equations (1) and (2) can be efficiently sent to the fuel electrode.

In order to achieve the above object, a twelfth invention is a layer in which an electrode reaction layer is a layer in which NiO and zirconia in which scandia is dissolved as a solid solution are uniformly mixed in a predetermined weight ratio (hereinafter, referred to as NiO / S).
Indicated as SZ. ), A layer in which NiO and cerium oxide are uniformly mixed at a predetermined weight ratio (hereinafter referred to as NiO / cerium oxide), and a predetermined weight of zirconia and cerium oxide in which NiO and scandia are dissolved. It is provided that it is any one of layers (hereinafter, referred to as NiO / SSZ / cerium oxide) uniformly mixed in a ratio.

According to the present invention, Ni having high electron conductivity, SSZ, cerium oxide, and SSZ / cerium oxide having high oxygen ion conductivity are selected as the electrode reaction layer.
It is possible to provide a solid oxide fuel cell having excellent output performance even at a power generation temperature of about 700 to 900 ° C.

The reason for this is SSZ, which has high oxygen ion conductivity.
Since it contains cerium oxide and / or cerium oxide, oxygen ions supplied from the electrolyte can be efficiently diffused into the electrode reaction layer even at a low temperature of about 700 ° C., and a Ni component having high electronic conductivity is contained. This is because the reaction of the formulas (1) and (2) can be promoted.

NiO / SSZ, NiO / cerium oxide, and NiO / SSZ / cerium oxide shown here reduce NiO to Ni in the fuel gas atmosphere of a solid oxide fuel cell, so that the layer is Ni / SSZ, Ni / cerium oxide, Ni / SSZ / cerium oxide.

The cerium oxide shown here is not particularly limited as long as it is an oxide containing cerium. General formula
(CeO ₂ ) _1-2X (B ₂ O ₃ ) _{X / 2} (6) (However, any one of B = Sm, Gd, Y, 0.05 ≦ X ≦ 0.15) is oxygen ion conductive. It has high properties and is preferable.

In order to achieve the above object, the thirteenth invention is such that the ratio of NiO in the electrode reaction layer is 100 parts by weight.
10 to 50 parts by weight are provided.

According to the present invention, since the NiO component in the electrode reaction layer is limited, the reactions of formulas (1) and (2) can be efficiently carried out.

The reason for this is that if the NiO component is less than 10 parts by weight, the electron conductivity is low and the electrons generated by the reactions of formulas (1) and (2) cannot be efficiently supplied to the fuel electrode.
On the other hand, if the NiO component is more than 50 parts by weight, the oxygen ion conductivity will be low, and the oxygen ions supplied from the electrolyte cannot be efficiently diffused into the electrode reaction layer.

In order to achieve the above object, the fourteenth invention provides that the solid solution amount of scandia in SSZ used in the electrode reaction layer is 3 to 12 mol%.

According to the present invention, since the solid solution ratio of SSZ is limited, it is possible to provide a solid oxide fuel cell having excellent output performance even at a power generation temperature of about 700 to 900 ° C.

The reason why the solid solution amount of scandia is preferably 3 to 12 mol% is that the crystal phase in this range is stable and the oxygen ion conductivity is high. From the viewpoint of high oxygen ion conductivity, a solid solution of 8 to 12 mol% is more preferable.

Further, the reason why the range other than 3 to 12 mol% is not preferable is that if the amount is less than 3 mol%, the oxygen ion conductivity is low, and the power generation temperature is low, the output performance is deteriorated.
This is because if the content is more than 1%, not only cubic crystal phases but also rhombohedral crystal phases are precipitated and the oxygen ion conductivity is reduced.

In order to achieve the above object, the fifteenth aspect of the invention is that SSZ in the electrode reaction layer further comprises one or more of rare earth oxides such as CeO ₂ , Y ₂ O ₃ and Bi ₂ O ₃ . An oxide is solid-dissolved, and a total of 5 mol% or less of the oxide is solid-dissolved.

According to the invention, CeO ₂ , Gd ₂ O ₃ , Y ₂ O _3, Yb ₂ O ₃
An appropriate amount of rare earth oxides such as Bi ₂ O ₃ and one or more oxides of Bi ₂ O ₃ are solid-solved, so that a solid oxide fuel cell having excellent output performance even at a power generation temperature of about 700 to 900 ° C. is provided. be able to.

The reason for this is that SSZ contains rare earth oxides and Bi.
_{When 2} O ₃ is dissolved as a solid solution, it has not only oxygen ion conductivity but also electron conductivity under a fuel gas atmosphere, and it is possible to promote the reactions of formulas (1) and (2), and Bi ₂ O 3. _This is because, such as ₃ , Y ₂ O _3, etc., may act as a sintering aid, and low-temperature sintering may be possible. A solid solution of two or more kinds is preferable because it may have both of the above two effects.
On the other hand, if these oxides are contained in an amount of more than 5 mol%, not only cubic crystals but also rhombohedral phases are precipitated as a crystal phase, and the oxygen ion conductivity is reduced.

In order to achieve the above object, the sixteenth invention provides that the electrolyte comprises zirconia in which yttria or scandia is dissolved.

According to the present invention, the electrolyte material is zirconia in which yttria or scandia is dissolved.
It is possible to provide a solid oxide fuel cell capable of obtaining high output performance even at 700 to 900 ° C.

The reason for this is that the oxygen ion conductivity is high and the material is stable. From the viewpoint of high oxygen ion conductivity, zirconia containing yttria or scandia in an appropriate amount is preferable.

In order to achieve the above object, the seventeenth invention provides that the fuel electrode is made of NiO / YSZ and the composition and the weight ratio thereof are 50/50 to 90/10.

According to the present invention, since the composition of the fuel electrode and the weight ratio thereof are limited, it is possible to provide a fuel electrode having high electron conductivity, excellent output performance and excellent durability.

The reason for this is that when NiO / YSZ is less than 50/50, the electron conductivity is lowered and electrons supplied from the electrode reaction layer cannot be efficiently carried. On the other hand, NiO / YSZ is less than 9
This is because if it exceeds 0/10, the Ni particles agglomerate during power generation and the output performance deteriorates. NiO / YSZ becomes Ni / YSZ because NiO is reduced to Ni in the fuel gas atmosphere of the solid oxide fuel cell.

In order to achieve the above object, the eighteenth invention provides that the air electrode is composed of lanthanum manganite represented by LaAMnO ₃ (A = Ca or Sr).

According to the present invention, since the composition of the air electrode is limited, it is possible to provide a solid oxide fuel cell having excellent output performance even at a power generation temperature of 700 to 900 ° C.

The reason is that the electron conductivity is high and the material is stable in an air atmosphere at 700 ° C. or higher.

In order to achieve the above object, the nineteenth invention provides an air side composed of lanthanum manganite / SSZ represented by LaAMnO ₃ (A = Ca or Sr) between the air electrode and the electrolyte. It is provided that the electrode reaction layer is interposed.

According to the present invention, La is placed between the air electrode and the electrolyte.
An air-side electrode composed of a layer (hereinafter referred to as LaAMnO ₃ / SSZ) in which lanthanum manganite represented by AMnO ₃ (either A = Ca or Sr) and zirconia in which scandia is dissolved as a solid solution are uniformly mixed. Since the reaction layer is provided, it is possible to provide a solid oxide fuel cell having excellent output performance even at an operating temperature of about 700 ° C.

The reason for this is that LaAMnO is present between the air electrode and the electrolyte.
₃ (either A = Ca or Sr), a lanthanum manganite material with high electron conductivity and a layer consisting of SSZ with high oxygen ion conductivity even at about 700 ° C. are provided (7)
This is because the electrode reaction that occurs between the air electrode and the electrolyte shown in the formula is promoted. ^{_{O 2 + 4e - → 2O 2-}} ... (7)

In order to achieve the above object, the 20th invention provides that the interconnector is a lanthanum chromite in which Ca is solid-dissolved.

According to the present invention, the use of lanthanum chromite containing Ca as a solid solution makes it possible to easily form a film having no gas permeability and to form an interconnector having high electronic conductivity.

The reason for this is that lanthanum chromite containing a solid solution other than Ca requires firing at a temperature higher than 1500 ° C. in order to form a film having no gas permeability, and at this temperature, a solid oxide fuel cell is required. This is because firing of causes a reaction between other constituent materials and reduces output performance.

[0077]

BEST MODE FOR CARRYING OUT THE INVENTION A solid oxide fuel cell according to the present invention will be described with reference to FIG. FIG. 1 is a view showing a cross section of a cylindrical solid oxide fuel cell. A strip-shaped interconnector 2 and an electrolyte 3 are provided on a cylindrical air electrode support 1, and a fuel electrode 4 is provided on the electrolyte 3 so as not to come into contact with the interconnector 2. When Air is supplied to the inside of the air electrode support and fuel is supplied to the outside, oxygen in Air is converted into oxygen ions at the interface between the air electrode and the electrolyte, and the oxygen ions reach the fuel electrode through the electrolyte. And
Fuel gas and oxygen ions react to produce water and carbon dioxide. These reactions are shown by the equations (1) and (2). Fuel pole 4
Electricity can be extracted to the outside by connecting the and the interconnector 2. ^{_{H 2 + O 2- → H 2}} O + 2e - ... (1) CO + O 2- → CO 2 + 2e - ... (2)

FIG. 2 is a sectional view showing a type in which an air side electrode reaction layer 5 is provided between the air electrode 1 and the electrolyte 3 and an electrode reaction layer 6 is provided between the electrolyte 3 and the fuel electrode 4. The air-side electrode reaction layer 5 is a layer provided in order to efficiently perform the reaction of the equation (7) in which oxygen ions are generated from the oxygen gas and electrons from the air electrode, and the oxygen generated in the air-side electrode reaction layer is used. Ions move to the fuel electrode side through the electrolyte. Then, the reactions represented by the formulas (1) and (2) are performed in the electrode reaction layer 6, and electricity can be taken out by connecting the fuel electrode 4 and the interconnector. Therefore, the air side electrode reaction layer, the electrolyte and the electrode reaction layer are important for obtaining high output characteristics up to a low temperature of about 700 ° C.

The role of the electrode reaction layer is to efficiently perform the reactions of the formulas (1) and (2) in the fuel gas atmosphere of the solid oxide fuel cell. For this purpose, as the electrode reaction layer, at least hydrogen gas (H ₂ ) and / or carbon monoxide gas (CO) contained in the fuel gas component, oxygen ions (O ^{2 −} ), and H
It is required to include ₂ O and / or CO ₂ and a catalyst that promotes a reaction to generate electrons, and have open pores in communication with each other. In order to improve the reaction efficiency, it is preferable to optimize the pore size and the porosity.

The electrode reaction layer in the present invention comprises at least hydrogen gas (H ₂ ) and / or carbon monoxide gas (CO), oxygen ions (O ^{2 −} ), H ₂ O and / or CO ₂ and electrons. There is no particular limitation as long as it contains a catalyst that accelerates the reaction that produces Cerium oxide, titanium oxide, Ni / YSZ, Ni
/ SSZ, a mixture of cerium oxide with a noble metal such as Ru or Pt, and the like.

The cerium oxide shown here is not particularly limited as long as it is an oxide containing cerium and satisfies the above conditions. Oxygen ion conductivity is represented by the general formula (CeO ₂ ) _1-2X (B ₂ O ₃ ) _X ... (6) (however, one of B = Sm, Gd and Y, 0.05 ≦ X ≦ 0.15). It has high properties and is preferable.

The titanium oxide shown here is not particularly limited as long as it is an oxide containing titanium and satisfies the above conditions. General formula (Ln _1-x M _x ) TiO ₃ (8) (where Ln: lanthanoid element, M: alkaline earth metal), M (Ti _1-y N _y ) O ₃
(9) (However, M: alkaline earth metal, N: Nb and other elements with a small ionic radius), (Ln _1-x M _x ) (Ti _1-y N _y ) O ₃ … (10) (however, Ln: lanthanoid element, M: alkaline earth metal, N: Nb
Examples thereof include a perovskite type oxide represented by an element having a small ionic radius).

As a material of the electrode reaction layer, oxygen ion conductivity is high, hydrogen gas and carbon monoxide gas can be diffused,
Further, those having electronic conductivity are preferable.
Further, those having a thermal expansion coefficient close to that of the electrolyte material, low reactivity with the electrolyte and the fuel electrode, and good adhesion between the electrolyte and the fuel electrode are preferable. If the material is good for all of these characteristics, it is possible to obtain high output characteristics even at a low temperature of about 700 ° C. From the above viewpoint,
NiO / SSZ, NiO / cerium oxide, and NiO / SSZ / cerium oxide are preferred.

Examples of the material having high oxygen ion conductivity in the electrode reaction layer in the present invention include SSZ and cerium oxide. Among them, it is preferable that the oxygen ion conductivity at 1000 ° C. is 0.1 Scm ⁻¹ or more because sufficient oxygen ion conductivity is obtained even at 700 ° C. low temperature.

The electrode reaction layer in the present invention may have a structure in which the NiO ratio is graded in order to enhance the electrode activity. For example,
It may be 10/90, 30/70, 50/50, etc. from the electrolyte toward the fuel electrode. From the viewpoint of alleviating the difference in thermal expansion and increasing the electrode activity, it is preferable to make the ratio inclined.

The raw material powder used in the electrode reaction layer in the present invention has an average particle size of about 0.3 to ² μm and a BET value of 1 to ²⁰ m ² g.
^-1 is preferable. The reason for this is that when a raw material having an average particle size of less than 0.3 μm is used, the open pores communicating with each other are almost eliminated, so that the diffusion of oxygen gas is low and the reactions of formulas (1) and (2) cannot be performed efficiently. On the other hand, on the other hand, in the electrode reaction layer composed of a raw material larger than 2 μm, the sinterability is low and the adhesion with the fuel electrode and the electrolyte is lowered, and the output performance is lowered. On the other hand, in the electrode reaction layer composed of a BET value smaller than 1 m ² g ^-1, high output performance cannot be obtained because there are few active sites that cause the reactions of formulas (1) and (2). Since the electrode reaction layer composed of a material having a ^{value of} more than 20 m ² g ^-1 has a high sinterability, the open pores communicating with the electrode reaction layer are almost eliminated, and the diffusion of hydrogen gas and carbon monoxide gas is low. This is because the reactions of formulas (1) and (2) cannot be carried out efficiently.

The BET value shown here is a value obtained by measurement using a flow-type specific surface area measuring apparatus Flowsorb II2300 manufactured by Shimadzu Corporation. The particle size distribution is a value obtained by measurement using a laser diffraction particle size distribution analyzer SALD-2000 manufactured by Shimadzu Corporation. Furthermore, the average particle size is
Shimadzu laser diffraction particle size distribution analyzer SALD-200
It is the value of the median diameter (50% diameter) obtained by measurement using 0.

The electrode reaction layer in the present invention may be formed by sloping the average particle diameter of the powder in order to enhance the electrode activity. For example, 0.5 μm from the electrolyte toward the fuel electrode, 1
Something like μm, 1.5 μm may be used. Further, the ratio of NiO may be inclined with the average particle size. Further, the BET value of the raw material powder may be inclined in order to enhance the electrode activity.

Regarding the ratio of SSZ and cerium oxide when three components of NiO / SSZ / cerium oxide are adopted in the electrode reaction layer in the present invention, the reaction of the formulas (1) and (2) proceeds efficiently. There is no particular limitation as long as it is.

There is no particular limitation on the method for preparing the raw material for the electrode reaction layer in the present invention. Examples thereof include a powder mixing method, a coprecipitation method, a spray pyrolysis method, and a sol-gel method.

A method in which NiO, SSZ, and cerium oxide are separately prepared by any one of the above methods, dispersed in an aqueous solution, a mixture is prepared by a wet method such as a spray drying method, and further heat treatment is performed. And a method in which each powder is mixed by a dry method in which it is mixed using a universal stirring mixer and the like, and further heat-treated to prepare.

The electrolyte in the present invention preferably has high oxygen ion conductivity, no gas permeability, and no electron conductivity in the air atmosphere and the fuel gas atmosphere of the solid oxide fuel cell. From this viewpoint, YSZ or SSZ is preferable. Alternatively, it may be zirconia in which yttria and scandia are dissolved.

The solid solution amount of yttria and scandia in YSZ and SSZ in the present invention is preferably about 3 to 12 mol.

The reason why the solid solution range of yttria is preferably 3 to 12 mol% is that if it is less than 3 mol%, the oxygen ion conductivity will be low. On the other hand, if it is more than 12 mol%, the crystal phase will be cubic. This is because a rhombohedral phase is precipitated in addition to the crystals and the oxygen ion conductivity is reduced.

However, the solid solution amount of yttria is 3 to 12 mol%.
Even in the range, the oxygen ion conductivity is high in the range of 900 to 1000 ° C, but greatly decreases below 900 ° C. Therefore 700
When YSZ is used as an electrolyte at a low temperature of about ℃, it is preferable to use it as a thin film.

The reason for this is that the use of a thin film can reduce the resistance loss inside the electrolyte and obtain high output performance even at 700 ° C.

The thin film shown here means that the thickness of the electrolyte is 50 μm.
Indicates less than m.

On the other hand, the solid solution range of scandia is 3 to 12 mol.
The reason for limiting the content to 3% is that if it is less than 3 mol%, the oxygen ion conductivity will be low. On the other hand, if it is more than 12 mol%, the crystal phase will be cubic and rhombohedral phases will precipitate, and the oxygen ion conductivity will be low. This is because it will decrease.

The reason why the scandia solid solution range is preferable is that the crystal phase is stable and the oxygen ion conductivity is high in this composition range. From the viewpoint of high oxygen ion conductivity, scandia solid solution containing 8 to 12 mol% is more preferable.

The electrolyte having no gas permeability shown here is
A pressure difference is provided between one side and the other side of the electrolyte, and the amount of gas permeated through the gap is evaluated, and the amount of gas permeation Q ≦ 2.
^{8 × 10 - 9 ms -1 Pa} -1 ( more preferably ^{Q ≦ 2.8 × 10 -10 ms -1} P
a ^-1 ).

The electrolyte in the present invention includes CeO ₂ , Sm ₂ O ₃ and Gd ₂
It may be a solid solution of O _3, Bi ₂ O ₃ or the like in an amount of 5 mol% or less. In particular, in zirconia containing solid solution of scandia, it is preferable that a small amount of these compositions is contained because oxygen ion conductivity becomes high and low temperature sintering becomes possible. Further, a small amount of a sintering aid may be added to produce an electrolyte having no gas permeability. Examples of the sintering aid include Al ₂ O ₃ and SiO ₂ .

The method for producing the electrolyte raw material in the present invention is not particularly limited as long as it is a method capable of uniformly forming the solid solution of scandia or yttria. The coprecipitation method is common.

The fuel electrode in the present invention preferably has a high electron conductivity in the fuel gas atmosphere of the solid oxide fuel cell and a high permeability to hydrogen gas and carbon monoxide gas. From this viewpoint, NiO / YS is used as the fuel electrode material.
Z is preferable, and the composition and the weight ratio thereof are 50/50 to 90/10.
Is preferred.

Regarding the composition of the fuel electrode in the present invention,
NiO / SSZ, NiO / calcium solid solution zirconia (hereinafter referred to as NiO / CSZ), or NiO / cerium oxide may be used. SS
Since YSZ is cheaper than Z, YSZ is preferable. However, since CSZ is cheaper than YSZ, NiO / CSZ is most preferable from the viewpoint of cost. Note that NiO / CSZ also becomes Ni / CSZ in fuel cell power generation.

The pore size of the fuel electrode in the present invention is not particularly limited as long as it is larger than the pore size of the electrode reaction layer, but other characteristics include high electron conductivity, high hydrogen gas and Those having carbon oxide gas permeability and good adhesion with the electrode reaction layer are preferable. Further, in the type in which the fuel electrode is used as a support, the fuel electrode itself is required to have strength, so that one having higher strength is preferable. From these viewpoints, the pore size of the fuel electrode is 1
〜30μm, 1〜20μ considering high strength
About m is preferable.

The porosity of the fuel electrode in the present invention is not particularly limited as long as it is equal to or higher than the porosity of the electrode reaction layer, but other characteristics include high electron conductivity, high hydrogen content and high hydrogen content. Those having carbon oxide gas permeability and good adhesion with the electrode reaction layer are preferable. Further, in the type in which the fuel electrode is used as a support, the fuel electrode itself is required to have strength, so that one having higher strength is preferable. From this viewpoint, the porosity of the fuel electrode is preferably about 10 to 60%, and about 10 to 50% in consideration of having high strength.

The particle size of the fuel electrode in the present invention is not particularly limited as long as it is larger than the particle size of the electrode reaction layer, but other characteristics include high electron conductivity, high hydrogen and carbon monoxide gas. It is preferable to have transparency and have good adhesion to the electrode reaction layer. Also,
In the type in which the fuel electrode is used as a support, the fuel electrode itself is required to have strength, so that one having higher strength is preferable. From this viewpoint, the particle size of the fuel electrode is preferably about 1 to 100 μm, and about 1 to 70 μm in view of having high strength.

The thickness of the fuel electrode in the present invention is not particularly limited as long as it is thicker than the electrode reaction layer, but other characteristics include high electron conductivity and high hydrogen and carbon monoxide gas permeability. It is preferable that the resin has good adhesion to the electrode reaction layer. Further, in the type in which the fuel electrode is used as a support, the fuel electrode itself is required to have strength, so that one having higher strength is preferable. From this viewpoint, the thickness is preferably about 30 μm to 3 mm, and considering the high strength, it is preferably about 0.5 mm to 3 mm.

Having high strength as shown here is radial crushing strength.
It indicates a material that exhibits 10 MPa or more. The radial crushing strength was measured by the following test.

The sample was placed between the compression jigs of the tester, pressed from above and below to be destroyed, and the load value at that time was used to calculate from the following formula. σr = P × (D−d) / (I × d ² ) ... (10) (σr: radial crushing strength, P: breaking load, D: outer diameter of sample, d:
Wall thickness, I: sample length)

The method for synthesizing the fuel electrode raw material in the present invention is not particularly limited as long as NiO / YSZ is uniformly mixed. A coprecipitation method, a spray dry method, etc. are mentioned.

It is preferable that the air electrode in the present invention has a high electron conductivity, a high oxygen gas permeability and an efficient reaction of the formula (7) in the air atmosphere of the solid oxide fuel cell. From this viewpoint, as a preferred material
The lanthanum manganite represented by LaAMnO3 (either A = Ca or Sr) can be mentioned.

The reaction of the formula (7) can be efficiently carried out,
From the viewpoint of improving the output performance, it is preferable to interpose the air-side electrode reaction layer between the air electrode and the electrolyte.

The air-side electrode reaction layer efficiently conducts the reaction of the formula (7).
With layers provided to do well and improve output performance
Therefore, it is preferable that the oxygen ion conductivity is high. Well
Further, if the electrode reaction layer further has electronic conductivity,
It is more preferable because it can accelerate the reaction.
Yes. Furthermore, the coefficient of thermal expansion is close to that of the electrolyte material,
And materials with low reactivity with the air electrode and good adhesion
It is preferably a charge. For all these characteristics
Good materials are high even at temperatures as low as 700 ° C
It is possible to obtain output characteristics. Preferred from the above viewpoint
LaAMnO as a good material ₃Expressed as (either A = Ca or Sr)
Lantern Manganite / SSZ etc.

In the present invention, LaAM of the air side electrode reaction layer
Lanthanum manganite represented by nO ₃ (either A = Ca or Sr) / LaAMnO ₃ represented by LaAMnO ₃ (either A = Ca or Sr) in SSZ has a composition of 7
Due to electronic conductivity and material stability at 00 ° C and above, (L
a _1-x Ax) _y MnO ₃ , the values of x and y are 0.15 ≦ x ≦ 0.
The range of 3, 0.97 ≦ y ≦ 1 is more preferable.

The reason for this is that the electron conductivity decreases in the range of x <0.15 and x> 0.3, and the reactivity becomes high and the activity of the electrode reaction layer decreases when y <0.97. This is because it reacts with zirconia to form an insulating layer represented by La ₂ Zr ₂ O ₇ and reduces the output performance of the cell.

In addition to Sr or Ca, lanthanum manganites in the electrode reaction layer include Ce, Sm, Gd, Pr, Nd, Co, Al, Fe and C.
It may be a solid solution of r, Ni or the like.

CeO ₂ , Sm ₂ O ₃ , Gd ₂ O ₃ , Bi ₂ O _{3 and the} like may be further solid-dissolved in SSZ of the air-side electrode reaction layer in the present invention in an amount of about 5 mol% or less. Also, two or more kinds of solid solutions may be used. When these materials are solid-dissolved, oxygen ion conductivity and / or sinterability can be expected to improve, so it is preferable to include them. In addition, LaAMnO ₃ (A =
It may be a layer in which lanthanum manganite represented by either Ca or Sr), SSZ and cerium oxide are uniformly mixed.

In the present invention, the composition of lanthanum manganite represented by LaAMnO ₃ (either A = Ca or Sr) of the air electrode is, from the viewpoint of electron conductivity at 700 ° C. or higher, stability of the material, etc., When expressed as La _1-x Ax) _y MnO ₃ , the values of x and y are more preferably in the range of 0.15 ≦ x ≦ 0.3 and 0.97 ≦ y ≦ 1.

The reason for this is that the electron conductivity decreases in the range of x <0.15 and x> 0.3, and the reactivity becomes high and the activity of the electrode reaction layer decreases when y <0.97. This is because it reacts with zirconia to form an insulating layer represented by La ₂ Zr ₂ O ₇ and reduces the output performance of the cell.

In addition to Sr or Ca, lanthanum manganite in the air electrode contains Ce, Sm, Gd, Pr, Nd, Co, Al, Fe, Cr, N.
It may be a solid solution of i or the like.

The method for producing the air electrode raw material in the present invention is not particularly limited. Examples thereof include a powder mixing method, a coprecipitation method, a spray pyrolysis method, and a sol-gel method.

The interconnector in the present invention preferably has high electron conductivity, no gas permeability, and no oxygen ion conductivity in the air atmosphere and the fuel gas atmosphere of the solid oxide fuel cell. From this viewpoint, lanthanum chromite is preferable.

Since lanthanum chromite is difficult to sinter, it is difficult to produce an interconnector having no gas permeability at the firing temperature (1500 ° C. or lower) of a solid oxide fuel cell. In order to improve the sinterability, it is preferable to use Ca, Sr, and Mg as a solid solution. A solid solution of Ca is most preferable because it has the highest sinterability and can form a membrane having no gas permeability at a temperature similar to that of other materials of the solid oxide fuel cell.

The solid solution amount of lanthanum chromite in which Ca is used as a solid solution used in the interconnector of the present invention is not particularly limited. The larger the solid solution amount of Ca, the higher the electronic conductivity, but the stability of the material decreases, so the solid solution amount of Ca is preferably about 10 to 40 mol%.

Regarding the method for producing the interconnector raw material in the present invention, it is preferable that the composition of lanthanum chromite in which Ca is solid-dissolved can be made uniform. From this viewpoint, the spray pyrolysis method and the citrate method are preferable.

The shape of the solid oxide fuel cell in the present invention is not particularly limited, and may be either a flat plate type or a cylindrical type. In the flat plate type, the interconnector is called a separator and has the same role as the interconnector. In the case of a separator, a metal such as stainless steel may be used.

The solid oxide fuel cell of the present invention is of the microtube type (outer diameter of 10 mm or less, more preferably 5 mm or less).
mm or less) is also applicable.

[0129]

Example 1 Example 1 A cylindrical solid oxide fuel cell shown in FIG. 1 was used. That is, a belt-shaped interconnector 2, an electrolyte 3, and a fuel electrode 4 on the electrolyte so as not to come into contact with the interconnector were used on a cylindrical air electrode support 1. Further, as shown in FIG. 2, an air side electrode reaction layer 5 was formed between the air electrode and the electrolyte, and an electrode reaction layer 6 was formed between the fuel electrode 4 and the electrolyte 3 was used.

(1) Preparation of air electrode support The composition of the air electrode was lanthanum manganite in which Sr represented by the La _0.75 Sr _0.25 MnO ₃ composition was dissolved, and the air electrode was prepared by coprecipitation and then heat-treated. An electrode raw material powder was obtained. Average particle size is 30μ
It was m. A cylindrical molded body was produced by an extrusion molding method. Further, it was fired at 1500 ° C. to obtain an air electrode support. The wall thickness was 2 mm.

(2) Preparation of air-side electrode reaction layer As the air-side electrode reaction layer, lanthanum manganite / SSZ was used.
And the composition and its weight ratio are La _0.75 Sr
The _{0.25 MnO 3/90 mol% ZrO} 2 -10mol% Sc 2 O 3 = 50/50 was used. After using each nitrate aqueous solution of La, Sr, Mn, Zr, and Sc so as to have the above composition, oxalic acid was added to cause precipitation. The precipitate was further heat-treated to control the particle size to obtain a raw material powder. The average particle size was 2 μm. 40 parts by weight of the electrode reaction layer powder 100 parts by weight of a solvent (ethanol),
After mixing 2 parts by weight of a binder (ethyl cellulose), 1 part by weight of a dispersant (polyoxyetalene alkylsonate), and 1 part by weight of a defoaming agent (sorbitan sesquioleate), the mixture was sufficiently stirred to prepare a slurry. The viscosity of this slurry was 100 mPas. The slurry is used as an air electrode support
A film was formed on the surface (outer diameter 15 mm, wall thickness 1.5 mm, effective length 400 mm) by a slurry coating method and then sintered at 1400 ° C. The thickness is
It was 20 μm.

(3) Preparation of electrolyte slurry: The electrolyte material was SSZ, and the composition was 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ . ZrO ₂ was dissolved in 3N or more concentrated nitric acid heated at 100 ° C. and diluted with distilled water to obtain a nitrate aqueous solution. Sc ₂ O ₃
An aqueous nitrate solution was obtained by the same method. Each nitrate aqueous solution was prepared so as to have the above composition, an oxalic acid aqueous solution was added, and coprecipitation was performed. 200 liquid obtained by co-precipitation
It was dried at about ℃, pyrolyzed at 500 ℃, and further heat-treated at 800 ℃ for 10 hours to obtain raw material powder. The average particle size was 0.5 μm. 40 parts by weight of the powder is 100 parts by weight of a solvent (ethanol),
After mixing 2 parts by weight of a binder (ethyl cellulose), 1 part by weight of a dispersant (polyoxyetalene alkylsonate), and 1 part by weight of a defoaming agent (sorbitan sesquioleate), the mixture was sufficiently stirred to prepare a slurry. The viscosity of this slurry was 140 mPas.

(4) Preparation of Electrolyte A film was formed on the electrode reaction layer by a slurry coating method and baked at 1400 ° C. The thickness of the obtained electrolyte was 30 μm.
Note that masking was applied to a portion where an interconnector was formed in a later step so that the film was not applied.

(5) Preparation of slurry for electrode reaction layer The material for the electrode reaction layer was NiO / SSZ, and the composition was NiO.
/ 90 mol% ZrO ₂ -10 mol% Sc ₂ O _3, and using each of the nitrate aqueous solutions of Ni, Zr and Sc to prepare the above composition, oxalic acid was added to cause precipitation. The precipitate was further heat-treated to control the particle size to obtain a raw material. The composition and weight ratio of the electrode reaction layer is NiO / 90 mol% ZrO ₂ -10 mol%
Sc ₂ O ₃ = 20/80 and 50/50 were prepared, and the average particle size was 0.5 μm in each case. 100 parts by weight of the powder, 500 parts by weight of an organic solvent (ethanol), 10 parts by weight of a binder (ethyl cellulose), 5 parts by weight of a dispersant (polyoxyetalene alkyl phosphate ester), 1 part by weight of a defoaming agent (sorbitane sesquiolate). Parts and 5 parts by weight of a plasticizer (DBP) were mixed, and then sufficiently stirred to prepare a slurry. The viscosity of this slurry was 70 mPas.

(6) Mask the battery so that the production area of the electrode reaction layer would be 150 cm ² .
NiO / 90 mol% ZrO ₂ -1 onto electrolyte by slurry coating method
0mol% Sc ₂ O ₃ (average particle size) = 20/80 (0.5 μm), 50/50 (0.5
(μm) in order. The film thickness (after firing) was 10 μm.

(7) Preparation of fuel electrode slurry: The material of the fuel electrode was NiO / YSZ, and the composition was NiO / 90 mol% ZrO ₂ -10 mol
% Y ₂ O _3, and using Ni, Zr, and Y nitrate aqueous solutions to prepare the above composition, oxalic acid was added to cause precipitation. The precipitate was further heat-treated to control the particle size and obtain a raw material. Composition and weight ratio are NiO / 90
mol% ZrO ₂ -10mol% Y ₂ O ₃ = 70/30, average particle size 5μ
It was m. 100 parts by weight of the powder and an organic solvent (ethanol)
500 parts by weight, 20 parts by weight of binder (ethyl cellulose), 5 parts by weight of dispersant (polyoxyethalene alkyl phosphate), 1 part by weight of antifoaming agent (sorbitane sesquiolate), 5 parts by weight of plasticizer (DBP) After mixing, the slurry was sufficiently stirred to prepare a slurry. The viscosity of this slurry is 250 mPa
It was s.

(8) Preparation of Fuel Electrode A fuel electrode was formed on the electrode reaction layer by a slurry coating method. The film thickness (after firing) was 90 μm. Furthermore, the electrode reaction layer and the fuel electrode were co-fired at 1400 ° C. The pore size of the fuel electrode after the power generation test was 6 μm, the porosity was 45%, and the particle size was 6.5 μm.

(9) Fabrication of interconnector: The composition of the interconnector is La _0.80 Ca _0.20 CrO ₃ and Ca represented by
Was obtained as a lanthanum chromite solid solution of which was prepared by spray pyrolysis and then heat-treated. The average particle size of the obtained powder was 1 μm. 40 parts by weight of the powder were used as 100 parts by weight of a solvent (ethanol), 2 parts by weight of a binder (ethyl cellulose), 1 part by weight of a dispersant (polyoxyethalene alkylsonate), and 1 part by weight of a defoaming agent (sorbitan sesquioleate). After mixing, the mixture was thoroughly stirred to prepare a slurry. The viscosity of this slurry was 100 mPas. An interconnector was formed into a film by a slurry coating method and baked at 1400 ° C. The thickness after firing was 40 μm.

Example 2 As a material for the electrode reaction layer, NiO / Y was used.
SZ, the composition is NiO / 90 mol% ZrO₂-10mol% Y ₂O₃When
However, the composition and the weight ratio are NiO / 90 mol% ZrO₂-10m
ol% Y₂O₃ = 20/80 and 50/50 are prepared and average particle
Same as Example 1 except that all diameters were 0.5 μm
I chose

Comparative Example 1 The same procedure as in Example 1 was carried out except that no electrode reaction layer was provided between the electrolyte and the fuel electrode.

(Power Generation Test) A power generation test was conducted using the cells (fuel electrode effective area: 150 cm ² ) obtained in Examples 1 and 2 and Comparative Example 1. The operating conditions at this time were as follows. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 800 ° C. Current density: 0.3Acm ^-2

[0142]

[Table 1]

Table 1 shows the results of the power generation potential at 800 ° C. and a current density of 0.3 Acm ⁻² . At the same current density, the higher the power generation potential, the better the output performance of the solid oxide fuel cell. In Examples 1 and 2, the performance is lower in Example 2 using YSZ to some extent due to the difference between the materials of Ni / SSZ and Ni / YSZ. On the other hand, in Comparative Example 1, it can be seen that the performance is significantly reduced. This is because no electrode reaction layer is interposed. From the above results, it was confirmed that it is preferable to provide the electrode reaction layer between the electrolyte and the fuel electrode.

Regarding Pore Size (Example 3) The composition of the electrode reaction layer was NiO / 90 mol% ZrO _2-.
The same method as in Example 1 was used except that 10 mol% Sc ₂ O ₃ was used, and the raw material had an average particle size of 0.3 μm and was fired at 1350 ° C.

Example 4 The composition of the electrode reaction layer was NiO / 9.
0 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ and the average particle size of the raw material is 1
The same method as in Example 1 was used except that a film having a thickness of μm was used.

Example 5 The composition of the electrode reaction layer was NiO / 9.
0 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ and the average particle size of the raw material is 2
The same method as in Example 1 was used except that a film having a thickness of μm was used.

Example 6 The composition of the electrode reaction layer was La
And _{0.75 Sr 0.25 MnO 3/90 mol} % ZrO 2 -10mol% Sc 2 O 3 = 50/50, the average particle diameter of the raw material by using one made of 0.1 [mu] m,
The same method as in Example 1 was performed except that the baking was performed at 1350 ° C.

Example 7 The composition of the electrode reaction layer was NiO / 9.
0 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ and the average particle size of the raw material is 5
The same method as in Example 1 was used except that a film having a thickness of μm was used.

Example 8 The composition of the electrode reaction layer was NiO / 9.
0 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ and the average particle size of the raw material is 0.
The same method as in Example 1 was used except that one having a thickness of 5 μm was used.

(Power Generation Test) A power generation test was conducted using the cells (fuel electrode effective area: 150 cm ² ) obtained in Example 1 and Examples 3 to 8. The operating conditions at this time were as follows. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 800 ° C. Current density: 0.3 Acm ^-2 Furthermore, after the power generation test, Example 1 and Example 4 to The pore diameter of the electrode reaction layer in 9 was measured.

[0151]

[Table 2]

Table 2 shows the results of the power generation potential at a current density of 0.3 Acm ^-2 at 800 ° C. It can be seen that the power generation potential varies depending on the pore diameter of the electrode reaction layer, even though the same material is used. It can be seen that the power generation potential is high in Examples 1, 3 to 5 and 8, but the potential is lowered in Examples 6 and 7. However, since it is higher than that of Comparative Example 1 shown in Table 1, there is no particular problem. From the above results, the pore size of the electrode reaction layer is 0.1 to 5 μm, which shows a high value of the generated potential.
It was confirmed that the degree was more preferable.

Porosity After the power generation test, the porosity of the electrode reaction layers in Example 1 and Examples 3 to 8 was measured.

[0154]

[Table 3]

Table 3 shows the results of the power generation potential at a current density of 0.3 Acm ^-2 at 800 ° C. It can be seen that the power generation potential differs depending on the porosity of the electrode reaction layer, even though the same material is used. It can be seen that the power generation potential is high in Examples 1, 3 to 5 and 8, but the potential is lowered in Examples 6 and 7. Although the potentials were lowered in Examples 6 and 7, there was no problem because it was higher than that in Comparative Example 1. From the above results, it was confirmed that the porosity of the electrode reaction layer is more preferably about 3 to 40%, which exhibits a high value of the power generation potential.

After the power generation test, the particle size in the cross-sectional direction of the electrode reaction layer in Example 1 and Examples 3 to 8 was measured.

[0157]

[Table 4]

Table 4 shows the result of the power generation potential at a current density of 0.3 Acm ^-2 at 800 ° C. It can be seen that the power generation potential varies depending on the particle size of the electrode reaction layer, even though the same material is used. It can be seen that the power generation potential is high in Examples 1, 3 to 5 and 8, but the potential is lowered in Examples 6 and 7. Although the potentials were lowered in Examples 6 and 7, there was no problem because it was higher than that in Comparative Example 1. From the above results, it was confirmed that the particle size of the electrode reaction layer is more preferably about 0.3 to 5 μm, which exhibits a high power generation potential.

Thickness of Electrode Reaction Layer (Example 9) The composition of the electrode reaction layer was NiO / 90 mol% ZrO _2-.
Example except 10 mol% Sc ₂ O ₃ and thickness of 3 μm
Same as 1.

Example 10 The composition of the electrode reaction layer was NiO /
Example 1 was repeated except that 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ was used and the thickness was 5 μm.

Example 11 The composition of the electrode reaction layer was NiO /
Same as Example 1 except that 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ was used and the thickness was 20 μm.

Example 12 The composition of the electrode reaction layer was NiO /
Same as Example 1 except that 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ was used and the thickness was 30 μm.

Example 13 The composition of the electrode reaction layer was NiO /
Same as Example 1 except that 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ was used and the thickness was 50 μm.

Example 14 The composition of the electrode reaction layer was NiO /
Example 1 was repeated except that 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ was used and the thickness was 2 μm.

Example 15 The composition of the electrode reaction layer was NiO /
Example 1 was repeated except that 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ was used and the thickness was 55 μm.

(Power Generation Test) A power generation test was conducted using the cells (fuel electrode effective area: 150 cm ² ) obtained in Example 1 and Examples 10 to 15. The operating conditions at this time were as follows. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 800 ° C. Current density: 0.3Acm ^-2

[0167]

[Table 5]

Table 5 shows the results of the power generation potential at 800 ° C. and a current density of 0.3 Acm ⁻² . It can be seen that the power generation potential differs depending on the thickness of the electrode reaction layer, even though the same material is used. It can be seen that the power generation potential is high in Examples 1 and 9 to 13, but the potential is lowered in Examples 14 and 15. In Examples 14 and 15 as well, although the potential was lowered, it was higher than that in Comparative Example 1, so there was no problem. From the above results, it was confirmed that the thickness of the electrode reaction layer is more preferably about 3 to 50 μm, which exhibits a high generated potential.

Electrode Reaction Layer Material (Example 16) The material of the electrode reaction layer was NiO / SSZ, the composition was NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ , and the composition and the weight ratio thereof. Is NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃
Same as Example 1 except that = 30/70 was set.

[0170] The material (Example 17) electrode reaction layer and NiO / cerium oxide, except that the said composition _{NiO / (CeO 2) 0.8 (} Sm 2 O 3) 0. 1 The same manner as in Example 1 I chose

Example 18 The material of the electrode reaction layer was NiO / SSZ / cerium oxide, and the composition was NiO / 90 mol% ZrO ₂ -10 mol%
Sc ₂ O ₃ / (CeO ₂ ) _0.8 (Sm ₂ O ₃ ) _0.1 , the composition and the weight ratio are NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ / (CeO ₂ ) _0.8 (Sm
₂ O ₃ ) _0.1 = 20/40/40 and 50/25/25. NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ and NiO / (CeO ₂ ) _0.8 (Sm ₂
O ₃ ) _0.1 was produced by the coprecipitation method.
l% ZrO ₂ -10mol% Sc ₂ O ₃ / (CeO ₂ ) _0.8 (Sm ₂ O ₃ ) _0.1 is 20/40/40
And 50/25/25 were mixed and heat-treated. Except for these, the same procedure as in Example 1 was performed.

(Power Generation Test) Using the test cells of Examples 1, 2, 16 to 18 and Comparative Example 1 (fuel electrode effective area: 150 cm ² ), the following power generation test was conducted. The operating conditions at this time were as follows. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 700 to 1000 ° C. Current density: 0.3 Acm ^-2

FIG. 3 shows the result of the power generation potential at the power generation temperature. It can be seen that in Examples 1 and 16 to 18, a high potential is exhibited at 700 to 1000 ° C. In contrast, the example
In No. 2, at 900 to 1000 ° C, there is almost no difference from Examples 1 and 16 to 18, but it can be seen that at 900 ° C or less, the performance is slightly deteriorated. Furthermore, in Comparative Example 1, 1000 ° C
It is also understood that in the above, the value is lower than that of the example, and the potential decrease further increases as the power generation temperature decreases. From the above results, it was confirmed that the power generation potentials were higher than those of Comparative Example 1 and were preferable. When the electrode reaction layer is NiO / YSZ, it has high output performance at 900-1000 ° C, and the electrode reaction layer has NiO / SSZ, NiO / cerium oxide and NiO / SSZ /
It was confirmed that cerium oxide is more preferable because it has excellent output performance even at about 700 ° C.

NiO Weight Ratio in Electrode Reaction Layer (Example 19) The material of the electrode reaction layer was NiO / SSZ, and the composition was NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ , and the composition and The weight ratio is NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃
Same as Example 1 except that = 10/90 was set.

Example 20 As a material for the electrode reaction layer, NiO /
SSZ, the composition was NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ , and the composition and the weight ratio were NiO / 90 mol% ZrO ₂ -10 m
Example 1 was repeated except that ol% Sc ₂ O ₃ = 50/50.

Example 21 As a material for the electrode reaction layer, NiO /
SSZ, the composition was NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ , and the composition and the weight ratio were NiO / 90 mol% ZrO ₂ -10 m
Example 1 was repeated except that ol% Sc ₂ O ₃ = 5/95.

Example 22 As a material for the electrode reaction layer, NiO /
SSZ, the composition was NiO / 90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ , and the composition and the weight ratio were NiO / 90 mol% ZrO ₂ -10 m
Same as Example 1 except that ol% Sc ₂ O ₃ = 55/45.

(Power Generation Test) A power generation test was conducted using the cells (fuel electrode effective area: 150 cm ² ) obtained in Example 16 and Examples 19 to 22. The operating conditions at this time were as follows. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 800 ° C. Current density: 0.3Acm ^-2

[0179]

[Table 6]

Table 6 shows the results of the power generation potential at a current density of 0.3 Acm ^-2 at 800 ° C. It can be seen that the high potential of 0.6 V or higher in Examples 16 and 19 and 20, whereas the potential was low in Examples 21 and 22. However, Example 2
Since the potentials of Nos. 1 and 22 were higher than those of Comparative Example 1 shown in Table 1, it was found that there is no problem if the voltage is reduced to this extent. From the above results, in the electrode reaction layer
It was confirmed that the weight ratio of NiO is more preferably 10 to 50 parts by weight.

Regarding solid solution amount of scandia in electrode reaction layer (Example 23) The material of the electrode reaction layer was NiO / SSZ, and the composition was N
iO / 97 mol% ZrO ₂ -3 mol% Sc ₂ O _{3 The same} as Example 1 except that.

Example 24 The same procedure was performed as in Example 1 except that the material for the electrode reaction layer was NiO / SSZ and the composition was NiO / 92 mol% ZrO ₂ -8 mol% Sc ₂ O ₃ .

Example 25 The same procedure was performed as in Example 1 except that the material for the electrode reaction layer was NiO / SSZ and the composition was NiO / 88 mol% ZrO ₂ -12 mol% Sc ₂ O ₃ .

Example 26 The same procedure was performed as in Example 1 except that the material for the electrode reaction layer was NiO / SSZ and the composition was NiO / 98 mol% ZrO ₂ -2 mol% Sc ₂ O ₃ .

Example 27 The same procedure was performed as in Example 1 except that the material for the electrode reaction layer was NiO / SSZ and the composition was NiO / 85 mol% ZrO ₂ -15 mol% Sc ₂ O ₃ .

Regarding the batteries of Example 1 and Examples 23 to 27,
A power generation test was conducted under the power generation conditions shown below. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 800 ° C. Current density: 0.3Acm ^-2

[0187]

[Table 7]

Table 7 shows the results of the power generation potential at a current density of 0.3 Acm ^-2 at 800 ° C. It can be seen that in Examples 1 and 17 to 19 the potential is high, whereas in Examples 20 and 21, the potential drop is somewhat low. However, Example 20,
Since 21 also exhibited a higher potential than Comparative Example 1 shown in Table 1, it was found that there was no problem at this level of decrease. Since the potential is high, SS in the electrode reaction layer
It was confirmed that the solid solution amount of scandia in Z is preferably in the range of 3 to 12 mol%. In addition, Example 1, Examples 17-1
When the data of Example 9 is compared, the potential of Example 18 is lower than the others, so that the amount of scandia solid solution is 8 to 12 mol.
It has been confirmed that it is more preferable if it is%.

Effect of CeO _{2 and the} like on SSZ (Example 28) The material of the electrode reaction layer was NiO / SSZ, and the composition was N
iO / 88 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ -2 mol% CeO ₂ , except that it was the same as in Example 1.

Example 29 The material of the electrode reaction layer was NiO / SSZ, and the composition was NiO / 85 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ -5 mol% C
The same procedure was performed as in Example 1 except that eO ₂ was used.

Example 30 The material of the electrode reaction layer was NiO / SSZ, and the composition was NiO / 84 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ -6 mol% C
The same procedure was performed as in Example 1 except that eO ₂ was used.

Example 31 The material of the electrode reaction layer was NiO / SSZ, and the composition was NiO / 88 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ -2 mol% B
Same as Example 1 except that i ₂ O ₃ was used.

Example 32 The material of the electrode reaction layer was NiO / SSZ, and the composition was NiO / 88 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ -2 mol% Y ₂ O.
_{The same} procedure as in Example 1 was performed except that the number was changed to ₃ .

Example 33 The material of the electrode reaction layer was NiO / SSZ, and the composition was NiO / 88 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ -1 mol% YC.
The same procedure was performed as in Example 1 except that eO ₂ -1 mol% Bi ₂ O ₃ was used.

Regarding the batteries of Example 1 and Examples 28 to 33,
A power generation test was conducted under the power generation conditions shown below. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 800 ° C. Current density: 0.3Acm ^-2

[0196]

[Table 8] Table 8 shows the results of the generated potential at 800 ° C and a current density of 0.3 Acm ^-2 . Comparing Example 1 and Examples 28 to 30, Example 2
8. In Example 29, the potential increased, but in Example 30, it tended to decrease. It was also confirmed that the sinterability of the electrode reaction layer material was improved in Example 31 and Example 32, although the potential was the same as in Example 1. In Example 33, it was confirmed that the potential was increased and the sinterability of the electrode reaction layer material was improved. From the above results, C in SSZ
It was confirmed that the solid-state solution of eO _{2 in an amount} of 5 mol% or less improves the output performance, and was found to be preferable. In addition, Y ₂ O ₃ and Bi
It was found that the solid solution of ₂ O ₃ improves the sinterability, which is preferable. It is easily assumed that even if 5 mol% or less of other rare earth oxides such as Gd ₂ O ₃ and Yb ₂ O ₃ are dissolved in solid solution, either the output performance or the sinterability is improved. Therefore, it was considered preferable.

Electrolyte Material (Example 34) The electrolyte material was YSZ, and the composition was 92 mol% ZrO 2.
Same as Example 1 except that it was ₂ -8 mol% Y ₂ O ₃ .

Using the test cells of Examples 1 and 34 and Comparative Example 1 (fuel electrode effective area: 150 cm ² ), the following power generation test was conducted. The operating conditions at this time were as follows. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 700 to 1000 ° C. Current density: 0.3 Acm ^-2

FIG. 4 shows the result of the power generation potential at the power generation temperature. In Example 34, the potential is almost the same at 1000 ° C., but the potential decreases at 900 ° C. or lower, and it is understood that the potential difference is considerably large at about 700 ° C. as in Example 1. However, it can be seen that there is a large difference from Comparative Example 1. From the above results, it was confirmed that SSZ is preferable as the electrolyte at the power generation temperature of 900 ° C. or lower, but it is almost the same at 900 ° C. or higher, and it is confirmed that there is no problem even if the electrolyte is YSZ.

Regarding NiO Weight Ratio in Fuel Electrode (Example 35) The material of the fuel electrode was NiO / YSZ, and the composition and its weight ratio were NiO / 90 mol% ZrO ₂ -10 mol% Y ₂ O ₃ = 50/50. Except for the above, the same procedure as in Example 1 was performed.

(Example 36) The material of the fuel electrode was NiO / YSZ,
Composition and weight ratio are NiO / 90 mol% ZrO ₂ -10 mol% Y ₂
Same as Example 1 except that O ₃ = 90/10.

(Example 37) The material of the fuel electrode was NiO / YSZ,
Composition and weight ratio are NiO / 90 mol% ZrO ₂ -10 mol% Y ₂
Same as Example 1 except that O ₃ = 45/55.

(Example 38) The material of the fuel electrode was NiO / YSZ,
Composition and weight ratio are NiO / 90 mol% ZrO ₂ -10 mol% Y ₂
Same as Example 1 except that O ₃ = 95/5.

Regarding the batteries of Example 1 and Examples 35 to 38,
A power generation test was conducted under the power generation conditions shown below. Fuel: (H ₂ + 11% H ₂ O): N ₂ = 1: 2 Oxidizing agent: Air Power generation temperature: 800 ° C. Current density: 0.3Acm ^-2

[0205]

[Table 9]

Table 9 shows the results of the power generation potential at 800 ° C. and a current density of 0.3 Acm ⁻² . It can be seen that in Examples 1 and 35 and 36, the potential is high, whereas in Examples 37 and 38, the potential is low. However, in Examples 37 and 38 as well, since the potential was higher than that of Comparative Example 1 shown in Table 1, it was found that there is no problem at this level of decrease. From the above results, it was confirmed that the weight ratio of NiO in the fuel electrode NiO / YSZ is more preferably 50 to 90 parts by weight.

By interposing the electrode reaction layer shown in Example 1 and Example 18, even at a low temperature of about 700 ° C.
It was possible to provide a solid oxide fuel cell having a high potential of 0.6 V or higher.

[0208]

As is clear from the above description, at least hydrogen gas (H ₂ ) and / or carbon monoxide gas (CO) contained in the fuel gas component and oxygen ions (O ₂ ) are contained between the electrolyte and the fuel electrode. ^2- ), and H ₂ O and / or CO ₂ and a catalyst that accelerates the reaction to generate electrons, and by providing an electrode reaction layer having communicating open pores, a solid oxide fuel with excellent output performance A battery can be provided.

[Brief description of drawings]

FIG. 1 is a view showing a cross section of a cylindrical solid oxide fuel cell.

FIG. 2 is a cross-sectional view showing in detail the air electrode, electrolyte and fuel electrode configuration of the solid oxide fuel cell shown in FIG.

[Figure 3] Power generation temperature (horizontal axis) and power generation potential of test battery (vertical axis)
It is a graph which shows the relationship of.

[Figure 4] Power generation temperature (horizontal axis) and power generation potential of test battery (vertical axis)
It is a graph which shows the relationship of.

[Explanation of symbols]

1: Air electrode support 2: Interconnector 3: Electrolyte 4: Fuel electrode 5: Air side electrode reaction layer 6: Electrode reaction layer

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 1, 2002 (2002.11.
1)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction content]

The cerium oxide shown here is not particularly limited as long as it is an oxide containing cerium. General formula
(CeO ₂ ) _1-2X (B ₂ O ₃ ) _X (6) (However, any one of B = Sm, Gd, Y, 0.05 ≦ X ≦ 0.15) has oxygen ion conductivity. High and preferred.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0110

[Correction method] Change

[Correction content]

The sample was placed between the compression jigs of the tester, pressed from above and below to be destroyed, and the load value at that time was used to calculate from the following formula. σr = P × (D−d) / (I × d ² ) ... ( 11 ) (σr: radial crushing strength, P: breaking load, D: outer diameter of sample, d:
Wall thickness, I: sample length)

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0112

[Correction method] Change

[Correction content]

It is preferable that the air electrode in the present invention has a high electron conductivity, a high oxygen gas permeability and an efficient reaction of the formula (7) in the air atmosphere of the solid oxide fuel cell. From this viewpoint, as a preferred material
The lanthanum manganites represented by LaAMnO ₃ (either A = Ca or Sr) can be mentioned.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0147

[Correction method] Change

[Correction content]

Example 6 The composition of the electrode reaction layer was NiO /
90 mol% ZrO ₂ -10 mol% Sc ₂ O ₃ = 50/50 was used, and the same method as in Example 1 was used except that the raw material having an average particle diameter of 0.1 μm was used and fired at 1350 ° C. .

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0188

[Correction method] Change

[Correction content]

Table 7 shows the results of the power generation potential at a current density of 0.3 Acm ^-2 at 800 ° C. It can be seen that in Examples 1 and 23 to 25, the potential is high, whereas in Examples 26 and 27 , the potential decrease is somewhat low. However, Example 26,
Also in 27 , a higher potential was exhibited as compared with Comparative Example 1 shown in Table 1, so it was found that there is no problem if the reduction is at this level. Since the potential is high, SS in the electrode reaction layer
It was confirmed that the solid solution amount of scandia in Z is preferably in the range of 3 to 12 mol%. In addition, Example 1, Examples 23-2
When the data of Example 5 are compared, the potential of Example 23 is lower than the others, so that the amount of scandia dissolved is 8 to 12 mol.
It has been confirmed that it is more preferable if it is%.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H018 AA06 AS02 BB01 BB06 BB08                       BB12 BB16 CC03 EE13 HH01                       HH03 HH05 HH06 HH08                 5H026 AA06 BB08 CV02 EE13 HH01                       HH03 HH04 HH05 HH06 HH08

Claims (20)

[Claims] 1. An air electrode, an electrolyte, and a fuel electrode are provided,
A solid oxide fuel cell in which an electrode reaction layer is interposed between the electrolyte and the fuel electrode, wherein the electrode reaction layer is at least hydrogen gas (H ₂ ) and / or contained in a fuel gas component.
Alternatively, carbon monoxide gas (CO), oxygen ions (O ^2- ), from H ₂ O and / or CO _2, and a catalyst that promotes a reaction to generate electrons, and has a continuous open pores. A characteristic solid oxide fuel cell. 2. The pore size of the electrode reaction layer is 0.1.
The solid oxide fuel cell according to claim 1, wherein the solid oxide fuel cell has a thickness of 5 μm. 3. The solid oxide fuel cell according to claim 1, wherein the electrode reaction layer has a pore size smaller than that of the fuel electrode. 4. The porosity of the electrode reaction layer is 3 to 40%.
The solid oxide fuel cell according to any one of claims 1 to 3, wherein 5. The solid oxide fuel cell according to claim 1, wherein a porosity of the electrode reaction layer is equal to or lower than a porosity of the fuel electrode. 6. The particle size in the electrode reaction layer is 0.3-5 μm.
The solid oxide fuel cell according to any one of claims 1 to 5, wherein m is m. 7. The particle size in the electrode reaction layer is smaller than the particle size in the fuel electrode.
7. The solid oxide fuel cell according to any one of items 6 to 6. 8. The thickness of the electrode reaction layer is 3 to 50 μm.
The solid oxide fuel cell according to any one of claims 1 to 7, wherein m is m. 9. The thickness of the electrode reaction layer is smaller than the thickness of the fuel electrode.
9. The solid oxide fuel cell according to any one of items 8 to 8. 10. The electrode reaction layer contains at least a material having an oxygen ion conductivity of 0.1 Scm ⁻¹ or more at 1000 ° C., according to any one of claims 1 to 9. The solid oxide fuel cell described. 11. The solid oxide fuel cell according to claim 1, wherein the electrode reaction layer contains at least Ni. 12. The electrode reaction layer is a layer in which NiO and zirconia in which scandia is dissolved as a solid solution are uniformly mixed in a predetermined weight ratio, and a layer in which NiO and cerium oxide are uniformly mixed in a predetermined weight ratio. , And NiO and scandia solid solution zirconia and cerium oxide are any one of the layers uniformly mixed at a predetermined weight ratio, 1.
The solid oxide fuel cell according to any one of items 1 to 11. 13. The ratio of NiO in the electrode reaction layer is 1
13. The solid oxide fuel cell according to claim 12, wherein the amount is 10 to 50 parts by weight with respect to 00 parts by weight. 14. In the zirconia in which scandia is dissolved in the electrode reaction layer, the amount of scandia dissolved is
The solid oxide fuel cell according to claim 12, wherein the content is 3 to 12 mol%. 15. The scandium solid solution zirconia further comprises one or two of rare earth oxides such as CeO ₂ , Gd ₂ O ₃ , Y ₂ O _{3 and} Yb ₂ O ₃ and Bi ₂ O _3. 15. The solid oxide fuel cell according to claim 12 or 14, wherein the above oxides are solid-solved, and the total amount of the oxides is 5 mol% or less. 16. The solid oxide fuel cell according to claim 1, wherein the electrolyte is zirconia in which yttria or scandia is dissolved. 17. The fuel electrode comprises a layer in which zirconia in which NiO and yttria are solid-dissolved is uniformly mixed at a predetermined weight ratio, and the NiO ratio is 50 to 90 parts by weight with respect to 100 parts by weight. The solid oxide fuel cell according to any one of claims 1 to 16, characterized in that it is present. 18. The air electrode is formed of LaAMnO ₃ (A = Ca or Sr).
The solid oxide fuel cell according to any one of claims 1 to 17, wherein the solid oxide fuel cell comprises a lanthanum manganite represented by any one of (1) to (17). 19. LaAMnO ₃ (A = Ca) between the air electrode and the electrolyte.
Lanthanum manganite represented by either Sr) and zirconia in which scandia is solid-dissolved in a predetermined weight ratio are characterized by interposing an air-side electrode reaction layer. The solid oxide fuel cell according to any one of claims 1 to 18. 20. The solid oxide fuel cell according to claim 1, wherein the interconnector in the solid oxide fuel cell is lanthanum chromite containing Ca as a solid solution.