JPH07267613A - Production of fine complex ceramic power, apparatus for production, the same ceramic powder and solid electrolytic type fuel cell containing the same ceramic powder as electrode material - Google Patents

Abstract

PURPOSE:To obtain fine complex ceramic powder which is solid spherical secondary particles formed by aggregating primary particles of materials by atomizing a mixture solution of plural materials into a mist, drying the resultant mist at a lower temperature than the thermal decomposition temperature of the materials and thermally decomposing the mist. CONSTITUTION:This method for producing fine complex ceramic powder is to introduce a material mixture solution (S) of two or more kinds into an atomizing chamber 2, operate ultrasonic oscillators 3 and 3, prepare a mist (M) having 1-20mum particle diameter, preheat the mist at 100 deg.C in the atomizing chamber 2, admit air which is a carrier gas from a gas inflow port 4 in the upper part of the atomizing chamber 2, move the preheated mist (M) in the interior of a quartz tube 5 communicating with the atomizing chamber 2, respectively regulate the heat source temperatures of heating zones (7A) and (7B) in an electric furnace 6 to 200 and 450 deg.C, initially gently dry the mist (M) by heating, regulate the heat source temperature of a heating zone (7C) to 800 deg.C which is the thermal decomposition temperature of the materials, thermally decompose the mist (M), successively move the mist (M) from the heating zones (7A) to (7B), (7C) and (7D), powder the mist, collect the resultant powder in an electric dust collector 8, calcine the powder at 1000 deg.C for 4 hr and pulverize the calcined powder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fine composite ceramic powder, a production apparatus, a fine composite ceramic powder, and a solid oxide fuel cell (hereinafter referred to as SOFC) characterized by using the fine composite ceramic powder as an electrode material. Also described)).

[0002]

2. Description of the Related Art In fine composite ceramic powder, primary particles of two or more kinds of materials are gathered in a mixed state to form secondary particles. As a conventional method for producing this fine composite ceramic powder, coarse powders of two or more kinds of materials are finely pulverized using a pulverizer, and the obtained pulverized materials of two or more types of materials are stirred and mixed with a ball mill. Calcination, calcination, pulverization or solution of two or more kinds of material powder, and the droplets are scattered in a heating furnace, pyrolyzed, calcined and pulverized to form fine secondary particles. There are decomposition methods. Some of the fine composite ceramic powders obtained by these conventional manufacturing methods are used as electrode materials for SOFCs.

[0003]

However, the secondary particles obtained by the conventional production method are produced by mechanically crushing the agglomerates formed by agglomeration of the primary particles, which are the particles of the material, The secondary particles obtained had an irregular shape, and it was difficult to obtain spherical particles. And when the ceramic powder obtained by the conventional manufacturing method was used for the electrode material of SOFC, the electrical property was inadequate. Therefore, an object of the present invention is to provide a fine composite ceramic powder that is a spherical solid secondary particle formed by aggregating primary particles of a plurality of materials, a manufacturing method suitable for manufacturing the powder, and a manufacturing method of the powder. An object of the present invention is to provide a suitable manufacturing apparatus and a solid oxide fuel cell using the fine composite ceramic powder as an electrode material.

[0004]

In order to solve the above-mentioned problems, a method for producing a fine composite ceramic powder according to claim 1 is to mist a solution in which two or more kinds of materials are mixed,
It is characterized by comprising a first step of drying the mist at a temperature lower than a temperature at which the material is thermally decomposed and a second step of thermally decomposing the material subsequent to the first step. Further, the apparatus for producing a fine composite ceramic powder according to claim 2 has a means for forming a mist of a solution in which two or more kinds of materials are mixed, a means for moving the mist, and a moving passage for the mist. Is characterized in that a plurality of heat generating means are arranged in the longitudinal direction. The fine composite ceramic powder according to claim 3 is the fine composite ceramic powder produced by the production method according to claim 1, and comprises two or more types of primary particles generated from two or more types of materials, and these The present invention is characterized by having solid and spherical secondary particles produced by aggregating two or more types of primary particles in a substantially uniformly dispersed state. A solid oxide fuel cell according to a fourth aspect is characterized in that the fine composite ceramic powder according to the third aspect is used as an electrode material.

The solution in which the above materials are mixed means a solution or a sol obtained by dissolving any material in any solvent, or a mixed solution of the solution and the sol. For example, as a powder material used for the air electrode of SOFC, , La, Sr and Mn ions, and YSZ (zirconium oxide stabilized with yttria) or PSZ (zirconium oxide partially stabilized). Other than yttria, zirconium oxide stabilized with, for example, calcium oxide can also be used. Alternatively, an aqueous solution containing La and Mn ions and Y
Examples thereof include a combination of SZ or PSZ, or an aqueous solution containing La and Co ions and YSZ or PSZ. The powder material used for the SOFC fuel electrode is, for example, a combination of the above YSZ or PSZ and Ni salts, or a YSZ or PSZ and Ni salt and Mg.
And a combination of salts. The solvent used for dissolving these materials to form a solution or sol may be an organic or inorganic aqueous solution of alkali or acid, water, etc., and various suitable solvents capable of dissolving the materials to form a solution or sol may be used. Can be used. Generally, a sol is a colloid in which a liquid is a dispersion medium and a solid is a dispersed particle, and although dispersed particles cannot be recognized by an ordinary optical microscope, they are dispersed as particles larger than atoms or small molecules. The sol in the present invention is not limited to this, and it is a slurry containing particles recognized by an optical microscope, or a slurry obtained by mixing ultrafine particles with a liquid such as water and suspending them, and easily forming a precipitate. It does not matter if it does not occur, and it is a sol in a broad sense that includes these. The powder material used for the SOFC electrolyte is, for example, YSZ or PS described above.
Combinations of Z and Al ₂ O ₃ or MgO are mentioned. Appropriate amounts of these materials can be selected, and fine composite ceramic powders having various compositions can be obtained by using any materials in any combination.

The thermal decomposition means a chemical change such as oxidation and / or crystallization of an amorphous substance. The crystallization means that the peaks of the X-ray diffraction of each material do not separate, It can be confirmed by

The primary particles generated from the particles of the material are particles obtained from the particles of the material through a chemical change such as oxidation and / or a physical change such as crystallization, and the secondary particles are It is a particle formed by collecting primary particles.
The fact that the secondary particles are solid means that the primary particles are also present inside the secondary particles.

The electrode means a fuel electrode and / or an air electrode, and both the fuel electrode and the air electrode are SOFCs using the fine composite ceramic powder according to claim 3 as an electrode material.
Only one of the fuel electrode or the air electrode includes both cases of SOFC using the fine composite ceramic powder according to claim 3 as an electrode material.

[0009]

According to the method for producing a fine composite ceramic powder as set forth in claim 1, the mist M is spherical as shown in FIG. 1, and particles P1 and P2 of two or more kinds of materials are contained in one mist M. Exist well dispersed. By the first step of drying the mist M, water or volatile components are evaporated from the surface of the mist M, and particles of two or more kinds of materials are well dispersed and exist in the particles R having a smaller diameter than the original mist M. Conceivable. By heating the material in the second step after the first step, the particles P1 and P2 of the material are thermally decomposed, the particle R is further reduced in diameter, and the thermally decomposed primary particles of two or more kinds of materials. It is considered that P1 and P2 have a well-dispersed spherical shape and become solid secondary particles TS.

Further, according to the apparatus for producing a fine composite ceramic powder of claim 2, a mist of the material solution is obtained by means of misting two or more kinds of material solutions, and the mist is moved by means of moving the mist. Move the moving passage of. Since a plurality of heat generating means are arranged in the longitudinal direction of this moving passage, the temperature of the heat generating means near the entrance of the moving passage of the mist is lower than the temperature at which the material is thermally decomposed. The method for producing the fine composite ceramic powder according to claim 1, wherein the temperature is a drying temperature, and the temperature of another heat generating means farther from the entrance of the moving passage of the mist is a temperature at which the material is thermally decomposed. Can be carried out.

According to the fine composite ceramic powder of claim 3, the manufacturing method of claim 1 provides
Spherical secondary particles different from conventional amorphous secondary particles are easily obtained, and since the secondary particles are spherical, it is regarded as a fine composite ceramic powder having properties different from those of the conventional fine composite ceramic powder. It Further, according to the solid oxide fuel cell of claim 4, since the fine composite ceramic powder of claim 3 is used as an electrode material, the contact part of the spherical secondary particles is the contact part of the irregular-shaped fine particles. Therefore, it is considered that the internal resistance is reduced. Also, since the secondary particles are solid particles produced by assembling two or more kinds of primary particles generated from the material solution in a substantially uniformly dispersed state, good electrical characteristics are expected.

[0012]

【Example】

Example 1 Production of fine composite ceramic powder used for an air electrode. La ₂ O ₃ 11.72 g, MnO ₂ 8.64 g and SrCO ₃
2.657 g of powder is mixed in 10 ml of pure water, 100 ml of concentrated nitric acid, 100 ml of hydrogen peroxide, and 150 ° C-
It stirred at 200 degreeC for 1 hour, and obtained the material solution I. As the material solution II, 63.4 g of 8 mol% YSZ sol was used. The above material solution I and the material solution II were mixed, pure water was added to make the total amount 1 liter, and this was mixed and stirred to obtain a material mixed solution S. Using the apparatus 1 for producing a fine composite ceramic powder shown in FIG.
A fine composite ceramic powder was produced as described below. As shown in FIG. 2, the manufacturing apparatus 1 includes an atomization chamber 2, a quartz tube 5 which is a passage for a mist communicating with the atomization chamber 2, and an electric furnace in which the quartz tube 5 passes through the quartz tube 5 with a certain length. 6 and an electrostatic precipitator 8 connected to a quartz tube 5 extended from the electric furnace 6. Below the atomization chamber 2, ultrasonic transducers 3 which are means for mistizing the material solution are installed.
A gas inlet 4 is installed in the upper part of the atomization chamber 2, and a means for moving the mist by introducing the carrier gas from the gas inlet 4 is realized. The temperature inside the atomization chamber 2 and the electric dust collector 8 can be adjusted by a temperature controller (not shown). In the electric furnace 6, four heating zones each having one electric heat generator installed at the left and right relative positions of the quartz tube 5 are installed at equal intervals in the length direction of the quartz tube 5. The quartz tube 5 has a length of 115 cm and a diameter of 40 mm. These four sets of heating zones are heated zones 7A, 7B, 7C, 7D in the order in which the mist M from the atomizing chamber 2 moves.
And

The material mixture S was put in the atomizing chamber 2 and the ultrasonic vibrators 3 were operated to form a fine mist M. The mist M had a particle size of 1 μm to 20 μm and an average particle size of 10 μm. This mist M was preheated to 100 ° C. in the atomization chamber 2. Next, air is introduced as a carrier gas at a rate of 3 cm / s from the gas inlet 4 at the top of the atomization chamber 2, so that the preheated mist M moves inside the quartz tube 5 communicating with the atomization chamber 2. Then, it moves to the quartz tube 5 in the electric furnace 6.

A heating zone 7A and a heating zone in the electric furnace 6.
Mist M is heated gently at first by setting the temperature of the heat source of the 7B to 200 ° C and 450 ° C, respectively.
Was dried. Then, the temperature of the heat source of the heating zone 7C is set to 800 ° C., which is the temperature at which the material is thermally decomposed, and the heating zone 7C is heated.
By setting the temperature of the heat source of D to 1000 ° C., the mist M was pyrolyzed after being dried. Heating zones 7A, 7B,
7C and 7D are sequentially moved, and the mist M pyrolyzed after drying is made into powder, and this powder is further moved to the outside of the electric furnace 6 inside the quartz tube 5 by the carrier gas and cooled by the electric dust collector 8. , Collected. The time required for the mist M to move from the atomization chamber 2 into the quartz tube 5 and be collected is about 30.
It was seconds. The powder thus collected is heated at 1000 ° C for 4
After calcination for a time, recrystallization, lightly loosening and crushing, a fine composite ceramic powder used in the air electrode of this example was obtained.

The microstructure of the above-mentioned fine composite ceramic powder was observed using a scanning electron microscope (hereinafter referred to as SEM) and an energy-dispersive X-ray analyzer (hereinafter referred to as EDX). 3 is a SEM photograph of the powder before calcination, FIG. 4 is a SEM photograph of the powder after calcination (magnification: 10,000 times), and FIG. 5 is a SEM photograph of the powder after calcination (magnification: 60,000 times). Figure 3
As shown in FIG. 5, a diameter of 0.1 μm formed by collecting primary particles having a diameter of 50 nm to 200 nm.
Secondary particles having a particle size of several μm and an average particle size of about 0.5 μm to 0.8 μm were obtained. These primary particles are (La _0.8 Sr _0.2 ) _0.9 MnO ₃ and YSZ from the EDX results,
It was found that these primary particles were uniformly and highly dispersed in the fine particles to form solid secondary particles. The diameter and number of secondary particles of the powder after calcination were measured by a method using laser diffraction scattering. The result is shown in FIG. Figure 6
In the figure, a bar graph shows% of the number of particles having a constant average diameter, and a line graph shows% of the cumulative number of secondary particles. The vertical axis on the left side shows% of the cumulative number of particles, the vertical axis on the left side shows% of the number of particles, and the horizontal axis shows the diameter of the particles (numerical unit: μm). As shown in FIG. 6, the particle size has a normal distribution and is distributed in a very narrow range.
For example, when the average particle size is 0.5 μm, the 90% particle size is 1.
It was 15 μm.

Example 2 Production of fine composite ceramic powder used for fuel electrode. 49.74 g of Ni (CH ₃ COO) ₂ .4H ₂ O and 10.72 g of Mg (CH ₃ COO) ₂ .4H ₂ O were dissolved in 1 liter of pure water to prepare a raw material solution I. As the raw material solution II, 37.75 g of 8 mol% YSZ sol was used. The raw material solution I and the raw material solution II are mixed, pure water is added to bring the total amount to 1 liter, and the raw material mixed solution S obtained by mixing and stirring this is the atomizing chamber of the manufacturing apparatus 1 shown in FIG. Mist M is prepared in the same manner as in Example 1 and thereafter, the mist M is first heated gently to dry it, and then the mist M is rapidly brought to the thermal decomposition temperature. Was pyrolyzed. And Example 1
Similarly to the above, the powder collected by cooling with the electrostatic precipitator 8 was calcined and crushed to obtain a fine composite ceramic powder used in the fuel electrode of this example. The fine composite ceramic powder obtained in this example was examined by SEM and EDX in the same manner as in Example 1. As a result, similar to the fine composite ceramic powder obtained in Example 1, a diameter of 0.1 μm formed by gathering two kinds of primary particles of (Ni, Mg) O and YSZ having a diameter of 50 nm to 200 nm Solid secondary particles having a particle size of several μm and an average particle size of about 0.5 μm to 0.8 μm were obtained.
It was found that these two types of primary particles were uniformly dispersed in the secondary particles to form solid secondary particles.
Further, as in Example 1, by the method by laser diffraction scattering,
When the diameter and number of particles of the powder after calcination were measured,
Similar to Example 1, the average particle size is about 0.5 μm to 0.8 μm.
Fine particles were obtained and the particle size was distributed in a very narrow range.

Example 3 Using the fine composite ceramic powder obtained in Examples 1 and 2, an electrode for a solid oxide fuel cell was prepared as follows. Polyethylene glycol as a binder was added to 2 g of the fine composite ceramic powder obtained in Example 2.
And 0.6 g of ethanol as a dispersant,
After mixing in an alumina automatic mortar for about 15 minutes to evaporate ethanol, 8 mol% YSZ pellets (diameter 13 mm, thickness
A screen (# (mesh) 200) was printed on 1 mm), and this was baked at 1400 ° C. for 2 hours. In this case, the fuel electrode wall thickness was 15 μm. Next, to 2 g of the fine composite ceramic powder obtained in Example 1, 0.6 g of polyethylene glycol as a binder and 6 g of ethanol as a dispersant.
Was added and mixed in an alumina automatic mortar for about 15 minutes to evaporate ethanol, and then screened on the back surface of the YSZ pellets.
(# (Mesh) 200) was printed, and this was baked at 1200 ° C. for 4 hours to form an air electrode. Finally set the reference pole to 10
Baking was performed under the conditions of 00 ° C. for 2 hours to obtain a performance evaluation cell of this example. The temperature rising conditions during baking were all 200 ° C./h.

Comparative Example 1 The same raw material solution I and raw material solution II as in Example 1 were mixed in the same manner, made up to 1 liter with pure water, and the raw material mixture S obtained by mixing and stirring was used in the production apparatus 1 shown in FIG. Under the same conditions as in Example 1 except that the temperature of the heating zone 7A was 700 ° C, the temperature of 7B was 800 ° C, the temperature of the heating zone 7C was 900 ° C, and the temperature of 7D was 1000 ° C. Mist-formed raw material mixture S
Was pyrolyzed to obtain a fine composite ceramic powder. The powder of Comparative Example 1 was examined by SEM and EDX in the same manner as in Example 1. FIG. 7 is a SEM photograph of the powder before calcination, and FIG. 8 is a SEM photograph of the powder after calcination (magnification: 10,000 times). As shown in FIGS. 7 and 8, there were many particles having a secondary particle size larger than that of the particles obtained in Example 1, and the particle size was distributed over a wide range. These large secondary particles were hollow as shown in the broken state of the large secondary particles in FIG. 8 and the results of EDX. The reason for this is that, as shown in FIG. 9, by heating the mist M with a sharp temperature gradient, evaporation of water occurs not only from the surface of the mist M but also from the inside of the mist M, so that the inside of the mist M is evaporated. It is considered that the existing particles P1 and P2 of the material gather on the surface portion of the mist M and form the solid-phase shell K, so that the hollow secondary particles KS are formed.

Comparative Example 2 A quartz tube in which a raw material mixed solution obtained by mixing and stirring the same raw material solution I and raw material solution II as in Examples 1 and 2 under the same conditions as in Examples 1 and 2 was maintained at 750 ° C. Pyrolysis was carried out at a rate of about 2 ml / min, and the obtained powders were roughly crushed and then calcined under the same conditions as in Examples 1 and 2,
It was crushed to obtain a ceramic powder. FIG. 10 is an SEM photograph (magnification: 10,000 times) of this ceramic powder. Figure 10
As shown in (1), the powder of Comparative Example 2 had a large difference from the powder of Example 1 (see FIGS. 3 to 5), and the particle shape was not spherical but amorphous. Further, when the diameter and number of particles of the powder after calcination were measured by the method by laser diffraction scattering as in Example 1, the particle size was higher than that of the powder of Example 1 as shown in FIG. It was large and distributed over a wide range. Using the ceramic powder of Comparative Example 2, a performance evaluation cell of Comparative Example was prepared in the same manner as in Example 3 and used in the following test examples.

Test Example The following test was conducted to compare the electrical performances of the performance evaluation cell of this example and the performance evaluation cell of Comparative Example 2. First, the resistance polarization of the air electrode and the fuel electrode at both current densities of 200 mA / cm ² was measured by the current interruption method. Measure the resistance polarization of the electrolyte separately and subtract 1/2 of the resistance polarization of the electrolyte from the resistance polarization of each of the air electrode and the fuel electrode to obtain the voltage loss of each of the air electrode and the fuel electrode excluding the resistance polarization of the electrolyte. Got The result of the voltage loss of the air electrode thus obtained is shown in FIG. 12, and the result of the voltage loss of the fuel electrode is shown in FIG.
In FIGS. 12 and 13, the vertical axis represents voltage loss (numerical unit: mV).
Bar graph A is the result for the cell of the comparative example, and bar graph B is the result for the cell of this example. Further, in the bar graphs A and B, the white portions show the values of resistance polarization, and the shaded portions show the values of activation polarization. As shown in FIGS. 12 and 13, the voltage loss of the electrode obtained by the method for producing a fine composite ceramic powder of the present invention is smaller than that obtained by the dropping pyrolysis method, and particularly as shown in FIG. The resistance polarization of the cathode voltage loss was greatly reduced.

Next, the relationship between the current density and the output density was investigated by measuring the voltage when a constant current was taken out using a galvanostat for both cells. The result is shown in FIG. In FIG. 14, the vertical axis represents the power density (number unit: W
/ cm ² ), and the horizontal axis shows the current density (numerical unit: mA / cm ² ).
Indicates. Graph I is the graph for the cell of this example.
II shows the results for the cells of the comparative examples. As shown in FIG. 14, in the electrode of the comparative example obtained by the dropping pyrolysis method, the power density of the cell (electrolyte 8 mol% YSZ 1 mmt) was 0.24 W / cm ² at a current density of 500 mA / cm ² .
After that, it tends to be almost constant, whereas the output density when using the electrode of this example obtained by the method for producing a fine composite ceramic powder of the present invention is a current density of 500 mA / c.
In m ^2, it exceeded 0.3 W / cm ² and tended to further increase.

As shown in the above test examples, the SOFC electrodes using the fine composite ceramic powders of Example 1 and Example 2 as the electrode material had a reduced internal resistance and improved electrical characteristics. Further, in the fine composite ceramic powder of this example, the primary particles of each material atom are highly uniformly dispersed in each secondary particle. Therefore, when the SOFC is operated at high temperature for a long time, fine particles of each atom are generated. Performance deterioration due to sintering can be suppressed.

Further, YSZ is generally used as the electrolyte of the fuel cell, and due to lack of strength, it is an obstacle to the increase in size.
When a composite material such as l ₂ O ₃ , MgO, or SiC is manufactured, a high-strength electrolyte material can be obtained.

[0024]

According to the method for producing a fine composite ceramic powder according to claim 1, the mist has a spherical shape, and the fine mist having spherical secondary particles is obtained by drying and then thermally decomposing the mist. Ceramic powder can be easily manufactured. According to the apparatus for producing a fine composite ceramic powder described in claim 2, the method for producing a fine composite ceramic powder according to claim 1 can be easily implemented. According to the fine composite ceramic powder of the third aspect, spherical secondary particles which are difficult to obtain by the conventional manufacturing method can be obtained. Therefore, new materials such as catalysts, fuel cell electrodes, etc. are provided. According to the solid oxide fuel cell of claim 3, the electric characteristics can be improved as compared with the conventional solid oxide fuel cell, so that the fuel cell, which is a future new battery having high power generation efficiency, can be put to practical use. Make a big contribution.

[Brief description of drawings]

FIG. 1 is an explanatory view of a manufacturing process of a fine composite ceramic powder of the present invention.

2 is an explanatory view of an apparatus for producing fine composite ceramic powder in Example 1. FIG.

FIG. 3 is an electron micrograph of the fine composite ceramic powder of Example 1.

FIG. 3 is an electron micrograph of the fine composite ceramic powder of Example 1.

5 is an electron micrograph of the fine composite ceramic powder of Example 1. FIG.

6 is a particle size distribution chart of the fine composite ceramic powder of Example 1. FIG.

7 is an electron micrograph of the fine composite ceramic powder of Comparative Example 1. FIG.

8 is an electron micrograph of the fine composite ceramic powder of Comparative Example 1. FIG.

FIG. 9 is an explanatory diagram of a manufacturing process of the fine composite ceramic powder of Comparative Example 1.

FIG. 10 is an electron micrograph of the fine composite ceramic powder of Comparative Example 2.

11 is a particle size distribution chart of the fine composite ceramic powder of Comparative Example 2. FIG.

FIG. 12 is a voltage loss comparison diagram at the air electrodes of the cells of Example 3 and the comparative example.

FIG. 13 is a voltage loss comparison diagram at the fuel electrodes of the cells of Example 3 and the comparative example.

FIG. 14 is a graph showing the relationship between the current density and the output density of the cells of Example 3 and Comparative Example.

[Explanation of symbols]

 1 Manufacturing Equipment 2 Atomization Chamber 3 Ultrasonic Transducer 4 Gas Inlet 5 Quartz Tube 6 Electric Furnace 7A, 7B, 7C, 7D Heating Zone 8 Electrostatic Precipitator M Mist S Raw Material Mixture P1 Material Particles P2 Material Particles TS Solid secondary particles

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C04B 35/626 35/495 H01M 4/48 4/86 T

Claims (4)

[Claims] 1. A first step of forming a mist of a solution in which two or more kinds of materials are mixed, and drying the mist at a temperature lower than a temperature at which the material is pyrolyzed, and the material following the first step. A method for producing a fine composite ceramic powder, which comprises a second step of thermally decomposing the above. 2. A means for mistizing a solution in which two or more kinds of materials are mixed, a means for moving the mist, and a moving passage for the mist, and a plurality of heat generating means in the longitudinal direction of the moving passage. An apparatus for producing a fine composite ceramic powder, characterized in that 3. The fine composite ceramic powder produced by the production method according to claim 1, comprising two or more types of primary particles generated from two or more types of materials, and two or more types of these primary particles. A fine composite ceramic powder characterized by having solid and spherical secondary particles produced by aggregating in a substantially uniformly dispersed state. 4. A solid oxide fuel cell, comprising the fine composite ceramic powder according to claim 3 as an electrode material.