JPH1021932A - Solid electrolyte type fuel cell and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolyte type fuel cell which can remarkably improve the effect of prevention of the cohesion and sintering of metal. SOLUTION: In a solid electrolyte type fuel cell where a porous air electrode 2 is made on one side of a solid electrolyte 3 and a porous fuel electrode 4 is made on the other side, the fuel electrode 4 is constituted of the metallic particles where fine ceramic particles 31 are deposited on the surface and inside. Moreover, the fuel electrode 2 consists of a porous body 36 which has ceramic particles 35 as skeletal structure, and besides inside the cavity of that porous body 36, metallic particles 39, where fine ceramic particles 33 are deposited on the surface and/or inside, are scattered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid oxide fuel cell and a method for manufacturing the same, and more particularly to an improvement in a fuel electrode.

[0002]

2. Description of the Related Art Conventionally, a solid oxide fuel cell has a high power generation efficiency because its operating temperature is as high as 1000 to 1050 ° C., and is expected as a third generation power generation system.

[0003] In general, a solid oxide fuel cell is known to be a cylindrical type or a flat type. Flat fuel cells are
Although it has the feature that the power density per unit volume of power generation is high, there are problems such as incomplete gas seals and non-uniformity of the temperature distribution in the cell in practical use. On the other hand, the cylindrical fuel cell has the features that the output density is low, but the mechanical strength of the cell is high and the temperature uniformity in the cell can be maintained. Both types of solid oxide fuel cells are being actively researched and developed utilizing their respective features.

As shown in FIG. 1, a single cell of a cylindrical fuel cell has a support tube 1 made of CaO-stabilized ZrO ₂ having an open porosity of about 40%, and a porous air made of LaMnO ₃ material on the support tube 1. A pole 2 is formed, and Y ₂ O ₃ stabilized Zr is formed on its surface.
A solid electrolyte 3 made of O ₂ is covered, and a porous Ni-zirconia fuel electrode 4 is provided on this surface. In a fuel cell module, each single cell is C
The connection is made with Ni felt through an interconnector 5 made of LaCrO ₃ -based material in which a, Sr, and Mg are dissolved. Such a power generation by a fuel cell requires 1000 cells for each unit cell.
This is performed by maintaining the temperature at about ° C. and supplying air (oxygen) 6 inside the support tube 1 and supplying a fuel gas 7, for example, hydrogen, city gas, or the like to the outside.

In recent years, attempts have been made to directly use a LaMnO ₃ -based material, which is an air electrode material, as a porous support tube in order to simplify the process in the cell fabrication process. A LaMnO ₃ solid solution material in which La is replaced by Ca or Sr by 10 to 20 atomic% is used as a support tube material having a function as an air electrode.

A single cell of a flat fuel cell uses the same material system as a cylindrical cell, and as shown in FIG. 2, a solid electrolyte 8 has a porous air electrode 9 on one side and a porous electrolyte 9 on the other side. An anode 10 is provided. Connection between single cells is separated
Dense LaC containing Mg and Ca, called
An rO ₃ material is used.

The fuel electrodes of the above-mentioned cylindrical and flat solid electrolyte fuel cells are generally made of Ni powder and ZrO ₂ (containing Y ₂ O ₃ ) powder or NiO powder and ZrO ₂ (Y ₂ O). ₃ ) The powder mixture was applied to the surface of the solid electrolyte by a screen printing method or immersed in a solution containing the mixed powder and then dried to form a fuel electrode. In addition, the latter NiO / ZrO
₂ (containing Y ₂ O ₃ ) in the case of a mixed powder,
Heat treatment was performed in a reducing atmosphere at 00 ° C. to form a fuel electrode.

[0008]

However, the fuel electrode produced by these methods cannot be used for a long period of power generation.
(NiO is reduced to Ni during power generation) and a large problem has occurred in that power generation performance is reduced by grain growth.

In recent years, in order to solve this problem, as disclosed in JP-A-7-22032, organometallic compounds such as octylates and naphthenates containing the elements Zr and Y are thermally decomposed, Fine Z on the surface of metal particles such as Ni
rO ₂ (containing Y ₂ O ₃ ) ceramic particles are precipitated and N
Although a method has been proposed to suppress performance degradation due to aggregation and sintering of i, this method was not sufficient to prevent aggregation and sintering of Ni.

[0010]

SUMMARY OF THE INVENTION As a result of studying the above problems, the present invention has been developed by depositing fine ceramic particles inside the metal particles simultaneously with the surface of the metal particles constituting the fuel electrode. The present inventors have found that the effect of suppressing coagulation and sintering is significantly improved, leading to the present invention. Further, in the present invention, a skeleton is formed by ceramic particles, and metal particles having fine ceramic particles precipitated on the surface and / or inside are dispersed in the pores of the skeleton, thereby further coagulating and sintering the metal. The present inventors have found that the effect of suppressing the occurrence of a fuel electrode can be improved and the adhesion strength of the fuel electrode to the solid electrolyte can be improved.

That is, the solid oxide fuel cell according to the present invention is a solid oxide fuel cell having a porous air electrode formed on one surface of a solid electrolyte and a porous fuel electrode formed on the other surface. Are composed of metal particles having fine ceramic particles precipitated on the surface and inside.

Further, the solid electrolyte fuel cell of the present invention is a solid electrolyte fuel cell in which a porous air electrode is formed on one side of the solid electrolyte and a porous fuel electrode is formed on the other side. Is composed of a porous material having ceramic particles as a skeleton, and the surface and / or
Alternatively, metal particles in which fine ceramic particles are precipitated are dispersed.

Further, according to the method for producing a solid oxide fuel cell of the present invention, a porous air electrode is provided on one surface of the solid electrolyte.
A method for manufacturing a solid oxide fuel cell having a porous fuel electrode formed on the other surface, wherein the fuel electrode is formed of Ni, C
An organic metal compound solution containing at least one metal element of o, Fe and Ru and Zr and / or Ce was applied to the surface of the solid electrolyte and thermally decomposed, and fine ceramic particles were deposited on the surface and inside. This is a method of forming with metal particles.

A method for manufacturing a solid electrolyte fuel cell having a solid electrolyte and a porous air electrode formed on one surface and a porous fuel electrode formed on the other surface, wherein the fuel electrode is made of Ni,
An organic metal compound solution containing at least one metal element of Co, Fe and Ru and Zr and / or Ce is injected into pores of a porous body having ceramic particles as a skeleton and thermally decomposed. This is a method of dispersing metal particles having fine ceramic particles precipitated on the surface and / or inside the pores of the porous body.

Further, the present invention provides a method for manufacturing a solid electrolyte fuel cell having a solid electrolyte and a porous air electrode formed on one surface and a porous fuel electrode formed on the other surface, wherein the fuel electrode is made of Zr and / or An organometallic compound solution containing Ce is mixed with Ni,
A metal consisting of Co, Fe and Ru, at least one of these metal oxides and alloys of said metals and ceramic particles are injected into pores of a porous body and thermally decomposed to form the porous body; In this method, metal particles having fine ceramic particles precipitated on the surface and / or inside are dispersed in the pores.

[0016]

In the solid oxide fuel cell of the present invention, an organic metal compound solution, for example, naphthenate, octylate, or the like is applied to the surface of the solid electrolyte in the fuel electrode, and thermally decomposed to produce fine ceramic particles, For example, ZrO ₂ fine particles are deposited on the Ni metal surface and ZrO ₂
By precipitating the fine particles, metal aggregation and grain growth are drastically suppressed.

In addition, by dispersing metal particles having fine ceramic particles precipitated on the surface and / or inside the pores of the skeleton (porous body) formed by the ceramic particles, metal aggregation and particle The growth is suppressed, the adhesion strength of the fuel electrode to the solid electrolyte is improved, and as a result, the output density is improved, and furthermore, a stable output can be obtained even in a heat cycle.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One of the basic structures of a fuel electrode in a solid oxide fuel cell unit according to the present invention is, for example, as shown in FIG. Has a structure in which fine ceramic particles 33 are precipitated in the form of a film and / or fine particles on the surface, and fine ceramic particles 33 are further deposited inside. The primary particle diameter of the fine ceramic particles 33 varies depending on the preparation conditions such as heat treatment conditions, but the average particle diameter is about 0.01 to 0.5 μm. The average particle size of the metal particles is desirably 1 to 20 μm, and 5 to 10 μm from the viewpoint of electric conductivity and gas permeability.

In the fuel electrode 4 of the present invention, as the metal particles 31, a simple substance of Co, Fe, and Ru in addition to Ni and an alloy thereof are used. The fine ceramic particles 33 include ZrO ₂ and CeO ₂ , a solid solution thereof, and a ZrO ₂ element containing 1 to 30 mol% of a rare earth element such as Y, Yb, Sc, Sm, Nd, Dy, or Pr. ₂ solid solution or CeO ₂ solid solution, and Z containing Y or rare earth element
A solid solution of rO ₂ and CeO ₂ can be used. Among them, Ni and Z are used as fuel electrode materials from the viewpoint of economy.
rO ₃ (containing Y ₃ O ₃ ) or a combination of Ni and CeO ₂ is preferred.

Such an anode structure is composed of Ni, Co, F
e, an organometallic compound solution simultaneously containing a metal element of Ru and Zr and / or Ce, for example, octylate;
Naphthenate, neodecanoate, ethylhexanoate,
A solution in which a propionate or the like is dissolved in a solvent such as toluene is applied to the surface of the solid electrolyte by a well-known technique such as screen printing or slurry dipping, and then applied at a temperature of 400 to 1600 ° C. in an oxidizing atmosphere. It is produced by thermal decomposition for 10 hours. The organometallic compound solution may contain an element selected from Y and rare earth elements. In a heat treatment in an oxidizing atmosphere, Ni, Co, and Fe metals are oxidized, and thus need to be reprocessed in a reducing atmosphere. In order to reduce the metal oxide, N 2 having an oxygen concentration of 1% or less is used.
_2. It is desirable to perform heat treatment in Ar.

In order to deposit fine ceramic particles 33 on the surface and inside of metal particles 31 such as Ni, it is necessary to use an organometallic compound solution containing metal particles such as Ni and Zr and / or Ce simultaneously. . In order to precipitate the fine ceramic particles 33 on the surface of the metal particles 31 such as Ni, a solution in which metal powder such as Ni is dispersed in an organic metal compound solution containing Zr and / or Ce is prepared.
It is obtained by applying this.

In the fuel electrode shown in FIG. 3, Ni, C
The weight ratio of the metal composed of O, Fe, and Ru to the oxide composed of Y and the rare earth element is such that Ni, Co, Fe, and Ru are 99 to 50% by weight in terms of metal, and the oxide of Zr and / or Ce (Y And the case containing a rare earth element) is preferably in the range of 1 to 50% by weight. 99 metals such as Ni
If the amount is more than the weight percentage, aggregation or grain growth of the metal during power generation cannot be sufficiently suppressed. On the other hand, metals such as Ni
If the amount is less than 0% by weight, the electric conductivity tends to decrease and the power generation performance tends to deteriorate. The weight ratio of the metal to the oxide is 80 to 90% by weight of the metal,
An oxide of Zr and / or Ce (including a case containing Y and a rare earth element) is particularly preferably 10 to 20% by weight.

The thickness of the fuel electrode is preferably 20 to 20 in the case of a flat cell from the viewpoints of electric conductivity and gas permeability.
In the case where 0 μm is a cylindrical cell, the range of 30 to 300 μm is excellent.

Another basic structure of the fuel electrode of the present invention is as follows.
As shown in FIG. 4, fine particles in the form of a film and / or particles are formed on the surface or in the inside of the pores of the porous body (skeleton) 36 composed of coarse ceramic particles 35 on the surface of the solid electrolyte 3. It has a structure in which metal 39 on which ceramic particles 37 are precipitated is dispersed. In such an anode 4, since the coarse ceramic particles 35 form a skeleton, the adhesion strength of the anode 4 to the solid electrolyte 3 is high, and peeling of the anode 4 due to a temperature cycle is extremely small. Has high power density. Both the ceramic particles 35 forming the skeleton and the fine ceramic particles 37 are made of ZrO ₂ , CeO ₂ alone or a solid solution thereof, or Y, Yb, Sc,
It is preferable to be composed of ZrO ₂ and CeO ₂ containing a rare earth element oxide such as Sm, Nd, Dy, and Pr.

In this case, the range of 50 to 95% by weight of metal (in terms of metal), 1 to 20% by weight of fine ceramic particles, and 4 to 30% by weight of coarse ceramic particles is excellent. When the metal content is more than 95% by weight, when the fine ceramic particles are less than 1% by weight, or when the coarse ceramic particles are less than 4% by weight, the effect of suppressing metal aggregation and grain growth during power generation. Is small. If the metal content is less than 50% by weight or fine ceramic particles
When the content is more than 0% by weight or when the amount of the coarse ceramic particles is more than 30% by weight, the electric conductivity tends to decrease and the power generation performance tends to deteriorate. In particular, if the metal is 60-8
0% by weight (in terms of metal), 10 to 10 fine ceramic particles
20% by weight, 10-20% by weight of coarse ceramic particles
Range is excellent.

The size of the coarse ceramic particles forming the skeleton is 0.5 to 30 μm in average particle size, particularly 2 to 30 μm.
The range of 10 to 10 μm is excellent. The size of the primary particles of the fine ceramic particles is 0.01 μm in average particle diameter.
The range of 0.5 to 0.5 μm, particularly 0.1 to 0.5 μm is excellent.

The ceramic skeleton in the fuel electrode is formed by first applying coarse ceramic particles to the surface of the solid electrolyte by a well-known technique such as screen printing or slurry dipping, and then immersing the particles in an oxidizing atmosphere at 1000 gram. ~ 1700
° C, preferably 1 to 10 at a temperature of 1200 to 1400 ° C.
It is formed by heat treatment for a time. Then, Ni, Co, Fe,
An organometallic compound solution simultaneously containing a Ru metal element and Zr and / or Ce, for example, octylate, naphthenate, neodecanoate, ethylhexanoate, propionate was dissolved in a solvent such as toluene. After the solution is impregnated into the skeleton, it is thermally decomposed at a temperature of 400 to 1600 ° C. in an oxidizing atmosphere to deposit fine ceramics on the metal surface and inside to form a fuel electrode.

Alternatively, coarse ceramic particles and Ni
O, CoO and other oxides containing Ni and Co metals are mixed, and screen printing or slurry is applied to the solid electrolyte surface.
After coating by a known technique such as dip, 1000 to 1700 ° C., preferably 1200 to 1700 ° C. in an oxidizing atmosphere.
Heat treatment is performed at a temperature of 400 ° C. for 1 to 10 hours to form a skeleton, and a metal oxide such as NiO or CoO is contained in the skeleton. Thereafter, an organic metal compound solution containing Zr and / or Ce simultaneously, for example, a solution in which octylate, naphthenate, neodecanoate, ethylhexanoate, and propionate are dissolved in a solvent such as toluene is used. After being impregnated in the skeleton, it is thermally decomposed at a temperature of 400 to 1600 ° C. in an oxidizing atmosphere to deposit fine ceramic particles on the surface of the metal oxide, and thereafter, a reduction treatment of a metal oxide such as NiO and CoO is performed. Is performed, a fuel electrode composed of metal particles having fine ceramic particles precipitated on the surface is formed in a framework composed of coarse ceramic particles.

Alternatively, a skeleton containing a metal oxide such as NiO or CoO is subjected to a treatment for reducing a metal oxide such as NiO or CoO, and then Zr and / or C
e) and an organic metal compound solution containing, for example, octylate, naphthenate or the like dissolved in a solvent such as toluene is injected into the skeleton.
r, N ₂ may be thermally decomposed to precipitate fine ceramic particles.

As the metal component in the fuel electrode, in addition to the above-mentioned oxides such as Ni and Co, carbonates, acetates, bromates and the like which form oxides by heat treatment can be used. .

In the above method, the organometallic compound solution may contain an element selected from Y and rare earth elements in addition to Zr and / or Ce.

The structure of the cylindrical fuel cell constructed according to the present invention has, for example, an open porosity of 40 as shown in FIG.
% Of Y ₂ O ₃ or CaO-stabilized ZrO ₂ as a support tube 1 and a LaMnO ₂ system in which La is replaced with Ca and Sr by 10 to 20 atomic% as a porous air electrode 2 by a slurry-dip method. A material is applied, and a solid electrolyte 3 is applied to the surface by vapor phase synthesis (EVD) or thermal spraying.
In a Y ₂ O ₃ stabilized ZrO ₂ film or Y ₂ O _3, Y
b ₂ O _3, or coated with a CeO ₂ film containing CaO,
Further, a porous fuel electrode 4 of the present invention is formed on this surface. Further, in the fuel cell unit of the present invention, an air electrode made of LaMnO ₃ in which La is replaced with Ca and Sr by 10 to 20 atomic% may be used as the support tube without using the support tube.

As a current collector called an interconnector 5, LaCrO ₃ to which 5-20 mol% of CaO or MgO is added is formed so as to be in contact with the air electrode by using a vapor phase synthesis method or a thermal spraying method. You.

Also, a flat cell can be manufactured as shown in FIG. 2 using the same material as that of the cylindrical cell.

The fuel cell of the present invention is not limited to the above-described structure, as long as it has an air electrode formed on one surface of the solid electrolyte and a fuel electrode formed on multiple surfaces.

[0036]

【Example】

Example 1 ZrO ₂ having a purity of 99.9% and an average particle diameter of 0.5 μm
Powder (containing 10 mol% of Y ₂ O ₃ ) and La _0.9 Sr _0.1 MnO ₃ air electrode powder having a purity of 99.8% and an average particle diameter of 2 μm were prepared. Ni, Co, Fe,
Ru, Zr, Ce, Y, Yb, Sc, Sm, N
A solution prepared by dissolving an octylate salt containing at least one of d and Dy in toluene was also prepared. The above 0.
After press forming 5 μm ZrO ₂ powder,
By baking at 00 ° C. for 3 hours, a solid electrolyte disc having a thickness of 0.3 mm and a diameter of 30 mm having a theoretical density ratio of 99.5% or more was produced. Thereafter, a La _0.9 Sr _0.1 MnO ₃ paste having an average particle diameter of 2 μm is applied to one surface of the solid electrolyte disc, and the paste is heat-treated at 1200 ° C. for 2 hours in the air to bake the solid electrolyte to form an air electrode. Formed. Further, a solution prepared by dissolving the above octylate in toluene was adjusted so as to have the composition shown in Tables 1 and 2, and then applied to one surface of the solid electrolyte, followed by heat treatment at 1200 ° C. in the air for 2 hours for thermal decomposition. To form a fuel electrode. For example, sample No. 6
In dissolving Ni, Zr, octyl acid salt each containing Y, Ni 80 wt%, the a ZrO ₂ from 20 wt%, in toluene as in ZrO ₂ Y ₂ O ₃ contains 10 mol% A fuel electrode was prepared using the solution thus obtained. At this time, the thickness of each of the air electrode and the fuel electrode was set to about 50 μm.
And

In the power generation, oxygen is supplied to the air electrode side and hydrogen is supplied to the fuel electrode side of the above-mentioned solid electrolyte to generate power at 1000 ° C.
The output density after 100 hours and the reduction rate of the output density after 3000 hours with respect to the output density after 100 hours were determined.

In this experiment, for comparison, NiO mixed with a conventional ball mill and having an average particle diameter of 5 μm and ZrO ₂ (Y ₂ O ₃ containing 10 mol%) and a weight ratio of N
i: A mixed powder of ZrO ₂ = 80: 20 was used as a fuel electrode (Sample No. 1). Further, N having an average particle diameter of 5 μm
Using a solution consisting of iO powder and an octylate containing Y and Zr, dispersing the NiO powder in the solution, applying this to one surface of the solid electrolyte, and heat-treating at 1200 ° C. in the air for 2 hours. The fuel electrode was formed by pyrolysis (Sample No. 2). In addition, the presence or absence of precipitation of fine ceramic particles on the metal surface and inside was observed with a scanning electron microscope. The results are shown in Tables 1 and 2.

[0039]

[Table 1]

[0040]

[Table 2]

From Tables 1 and 2, it can be seen that Sample No. 1 has a metal ratio of more than 99% by weight. As for No. 3, it can be seen that the decrease in output density due to long-time power generation is slightly large. Also, if the metal ratio is 50
Sample No. less than wt. In 10, 12, and 46, although the decrease in the output density is small, the absolute value of the output density is small because the electrical conductivity is slightly low. On the other hand, those having a metal ratio in the range of 50 to 99% by weight all had high output densities and small reduction rates. From observation by a scanning electron microscope, precipitation of fine ceramic particles was observed on the surface and inside of the metal particles in all of the samples of the present invention.

Example 2 ZrO ₂ (1) having a purity of 99.9% and an average particle diameter of 3 μm
0 mol% containing Y ₂ O ₃ , Yb ₂ O ₃ )
After adding and mixing a volume-% flow beads (trade name) pore-forming agent, the mixture was applied to one surface of a solid electrolyte disk having an air electrode formed on one surface in Example 1 and then exposed to air at 1400 ° C. For 2 hours to form a porous body (skeleton) made of coarse-grained ceramic with a thickness of about 50 μm on the surface of the solid electrolyte. The N of Example 1 was set so that the pores of this porous body had the composition shown in Table 3.
i, Co, Fe, Ru, Zr, Ce, Y, Y
After injecting a solution of octylate containing at least one of b, Sc and Sm in toluene, 1000
Heat treatment was performed at 2 ° C. for 2 hours to perform thermal decomposition to form a fuel electrode. At this time, the weight ratio of the coarse-grained ceramics forming the skeleton in the table was obtained from the weight change before and after the heat treatment at 1400 ° C. Thereafter, a power generation test and observation of fine ceramic particles were performed according to Example 1, and the results are shown in Table 3.

[0043]

[Table 3]

From Table 3, it can be seen that Sample No. 5 in which the metal ratio is less than 50% by weight. In 53, although the decrease in the output density is small, the absolute value of the output density is slightly small due to the low electrical conductivity. Sample No. 1 in which fine ceramic particles exceeded 20% by weight. At 55 and 67, the absolute value of the output density is slightly smaller. From observation by a scanning electron microscope, precipitation of fine ceramic particles was observed on the surface and inside of the metal particles in all of the samples of the present invention.

Example 3 Zr having a purity of 99.9% and an average particle diameter of 5 μm each
O ₂ (10 mol% containing Y ₂ O ₃ , Yb ₂ O ₃ ) powder;
After mixing CeO ₂ powder, NiO, CoO, FeO, and Ru powders and about 5 to 30% by volume of a pore-forming agent of flow beads (trade name) so as to have a composition shown in Table 4, Coating on one surface of a solid electrolyte disk having an air electrode formed on one surface of Example 1 and heat treatment at 1400 ° C. for 2 hours, coarse particles containing about 50 μm thick NiO, CoO, FeO, and Ru on the surface of the solid electrolyte A skeleton made of ceramic was formed.

In this skeleton, Z is set so as to have the composition shown in Table 4.
After injecting a solution of octylate containing r, Ce, Y, Yb, Sc, and Sm in toluene, 10
NiO, C heat treated at 00 ° C for 2 hours to cause thermal decomposition
The fuel electrode was formed by depositing fine ceramic particles on the surfaces of oO, FeO, and Ru. At this time, the weight ratio of the coarse-grained ceramic and metal forming the skeleton in the table was obtained from the weight change before and after the heat treatment at 1400 ° C. Thereafter, a power generation test and observation of fine ceramic particles were performed according to Example 1, and the results are shown in Table 4.

[0047]

[Table 4]

From Table 4, it can be seen that Sample No. 1 in which the metal ratio exceeds 95% by weight and the ratio of coarse ceramic particles is less than 4% by weight. In the case of No. 68, it can be seen that the reduction rate of the output density is slightly large. Sample No. having a metal ratio of less than 50% by weight. In the case of No. 74, although the decrease of the output density is small, the absolute value of the output density is slightly small due to the low electric conductivity. Sample No. 1 in which fine ceramic particles exceeded 20% by weight. At 76, it can be seen that the absolute value of the output density is slightly smaller. From observation by a scanning electron microscope, precipitation of fine ceramic particles was observed on the surfaces of the metal particles in all of the samples of the present invention. Example 4 The samples prepared in Examples 1, 2 and 3 were cooled from room temperature to 100
The temperature was raised to 1000 ° C at a rate of
After holding for a time, the mixture was cooled to room temperature at a rate of 100 ° C./h. This temperature change was defined as one cycle, and after repeating 20 cycles, a power generation test was performed in accordance with Example 1 to determine an output density. Table 5 shows the results.

[0049]

[Table 5]

According to Table 5, all the samples in which the coarse-grained ceramic skeleton was formed in the fuel electrode were samples N having no skeleton formation.
o. It can be seen that the decrease in the output density after the heat treatment is smaller than that of 88 and 89. After the power generation test, peeling was observed in fuel electrode samples Nos. 88 and 89 having no skeleton formed, but no peeling was observed in the sample having the skeleton formed.

Example 5 La _0.9 Ca having a purity of 99.9% and an average particle diameter of 8 μm
A hollow cylindrical molded body, one end of which is sealed by an extrusion molding method using _0.1 MnO ₃ powder, is prepared and fired at 1500 ° C. for 3 hours, has an open porosity of 32%, a thickness of 2 mm, and an outer diameter of 15 m.
An air electrode support tube having a length of 200 mm and a length of 200 mm was prepared. Thereafter, the thickness of the air electrode support tube is about 5
0μm of ZrO ₂ (10 mol% Y ₂ O ₃ content) electrolyte and of La _{0. 9} Ca _0.1 CrO ₃ interface - after forming the connector, 70 [mu] m the fuel electrode of the present invention to the solid electrolyte surface
To form a cylindrical cell. Power is generated by flowing air inside the cathode support tube and hydrogen outside,
And power generation was performed for about 5000 hours, and a time change of the output density was observed. FIG. 5 shows the results.

From FIG. 5, it can be seen that Sample No. 6, 6
1 and 85, the conventional cell No. It can be seen that the decrease in the output density is extremely small as compared with 1 and 2. From these results, it is understood that the cylindrical fuel cell of the present invention is a cell having a high output density and excellent long-term stability.

[0053]

In the solid oxide fuel cell unit according to the present invention, in the fuel electrode, fine ceramic particles are deposited on the surface of the metal and at the same time on the inside, so that metal agglomeration and particle growth are dramatically increased. Is suppressed. Also,
By impregnating and dispersing metal particles in which fine ceramic particles are deposited at least on the surface and / or inside the pores of the skeleton (porous body) formed by the ceramic particles, metal aggregation and dispersion can be dramatically achieved. In addition to suppressing grain growth, the adhesion strength of the fuel electrode to the solid electrolyte is improved,
As a result, the output density can be improved, and at the same time, a stable output can be exhibited even in a heat cycle.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a cylindrical solid oxide fuel cell of the present invention.

FIG. 2 is a perspective view showing a flat solid electrolyte fuel cell unit according to the present invention.

FIG. 3 is a conceptual diagram showing a state in which a fuel electrode is composed of metal particles having fine ceramic particles precipitated on the surface and inside.

FIG. 4 is a conceptual diagram showing a state in which a fuel electrode is formed by dispersing metal particles having fine ceramic particles precipitated on the surface and / or inside pores of a porous body having a ceramic particle skeleton. is there.

FIG. 5 is a graph showing a time change of an output density.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Support tube 2 ... Air electrode 3 ... Solid electrolyte 4 ... Fuel electrode 5 ... Current collecting member 31 ... Metal particles 33, 37 ... Fine ceramic particles 35 ...・ Coarse ceramic particles 36 ・ ・ ・ porous body (framework) 39 ・ ・ ・ metal

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Matsuzaki 3-28-70 Minamisenju, Arakawa-ku, Tokyo

Claims (5)

[Claims] 1. A solid electrolyte fuel cell having a solid electrolyte and a porous air electrode formed on one side and a porous fuel electrode formed on the other side, wherein the fuel electrode has fine ceramic particles on the surface and inside. A solid oxide fuel cell comprising: deposited metal particles. 2. A solid electrolyte fuel cell in which a porous air electrode is formed on one side of a solid electrolyte and a porous fuel electrode is formed on the other side, wherein the fuel electrode has a porous body having ceramic particles as a skeleton. A solid electrolyte fuel cell comprising: metal particles having fine ceramic particles deposited on the surface and / or inside the pores of the porous body. 3. A method for manufacturing a solid oxide fuel cell comprising a solid electrolyte having a porous air electrode on one surface and a porous fuel electrode on the other surface, wherein the fuel electrode is made of Ni, Co, F
e and Ru, at least one metal element, and Zr
And / or an organic metal compound solution containing Ce is applied to the surface of the solid electrolyte and thermally decomposed, and formed by metal particles having fine ceramic particles precipitated on the surface and inside thereof. Manufacturing method. 4. A method for manufacturing a solid oxide fuel cell having a porous air electrode formed on one side of a solid electrolyte and a porous fuel electrode formed on the other side, wherein the fuel electrode is made of Ni, Co, F
at least one or more metal elements of e and Ru;
An organometallic compound solution containing Zr and / or Ce,
Injecting into the pores of a porous body having ceramic particles as a skeleton and thermally decomposing, and dispersing metal particles having fine ceramic particles deposited on the surface and / or inside the pores of the porous body. A method for producing a solid oxide fuel cell, comprising: 5. A method for manufacturing a solid electrolyte fuel cell having a solid electrolyte and a porous air electrode formed on one side and a porous fuel electrode formed on the other side, wherein the fuel electrode is formed of Zr and / or Zr. An organometallic compound solution containing Ce is mixed with Ni, Co, F
a metal consisting of e and Ru, at least one of these metal oxides and alloys of said metals, and ceramic particles are injected into pores of a porous body and thermally decomposed;
A method for manufacturing a solid oxide fuel cell, comprising dispersing metal particles having fine ceramic particles precipitated on the surface and / or inside the pores of the porous body.