JP2011190149A - Composite ceramic powder and method for producing the same, and solid oxide fuel cell - Google Patents

Abstract

Disclosed is a method for producing a composite ceramic powder excellent in distribution and composition controllability of oxide particles at the nanometer level.
A perovskite oxide or nickel oxide represented by at least A _1-x B _x C _1-y D _y O ₃ , zirconia in which metal ions are dissolved and oxygen ion conductivity is imparted, A composite ceramic powder containing
_First , zirconium ions and carbonate ions are reacted in a basic aqueous solution to form a basic zirconium carbonate complex, and then A constituting A _1-x B _x C _1-y D _y O ₃ , A metal ion or nickel ion selected from the group of B, C and D and a metal ion are coprecipitated with a basic zirconium carbonate complex, and the precipitate is heated at a temperature of 200 ° C. or higher. Heat treatment.
[Selection figure] None

Description

The present invention relates to composite ceramic powder, a method for producing the same, and a solid oxide fuel cell (SOFC), and more specifically, zirconia particles, A _1-x B _x C _1-y D _y O, and the like. Composite powder having excellent particle distribution and composition controllability, and a method for producing the same, and using the composite ceramic powder as a material for an electrode, comprising perovskite-type oxide particles or nickel oxide particles having a composition represented by ₃ The present invention relates to the solid oxide fuel cell used.

  In recent years, with the growing awareness of the environment, development of fuel cells that extract electric power by an electrochemical reaction has been actively conducted in place of a power generation device that uses a conventional heat engine. A solid oxide fuel cell, which is a type of fuel cell, has a high operating temperature of 600 ° C. or higher, and therefore a ceramic material having excellent heat resistance is used for the electrode.

In the field of solid oxide fuel cells, each electrode has a role as a reaction catalyst, and it is said that a reaction field is a three-phase interface.
First, the three phases in the air electrode (positive electrode) of the solid oxide fuel cell are ceramic particles exhibiting oxygen ion conductivity, ceramic particles constituting the electrode, and gas such as air. For example, A _1-x B _x C _1-y D _y O ₃ (wherein A is one or two elements selected from the group of La and Sm, and B is Sr, Ca and Ba as the air electrode) One or more elements selected from the group, C is one or more elements selected from the group of Co, Ga and Mn, D is selected from the group of Fe, Mg and Ni Is a seed or two or more elements, 0.1 ≦ x ≦ 0.5, 0 ≦ y ≦ 1.0) and yttria-stabilized zirconia (YSZ) composite material (A _1-x B _x C _{1- y} D _y O ₃ -YSZ), in a system using a yttria-stabilized zirconia as a solid _{electrolyte, a 1-x B x C} 1-y D y O 3 is a ceramic particles constituting the electrode, oxygen ion conductivity Yttria-stabilized zirconia and ceramic particles 3 components are in contact with all parts of the gas and the like is three-phase interface. Therefore, the output characteristics of the solid oxide fuel cell can be improved by increasing the three-phase interface of the air electrode, improving the oxygen reducing ability, and improving the electronic conductivity.

The three phases in the fuel electrode (negative electrode) of the solid oxide fuel cell are ceramic particles exhibiting oxygen ion conductivity, metal constituting the electrode, or fuel gas such as ceramic particles and hydrogen. For example, in a system using nickel-yttria-stabilized zirconia composite material (Ni-YSZ) as the fuel electrode and yttria-stabilized zirconia as the solid electrolyte, the metal constituting the electrode is nickel, and the ceramic particles exhibit oxygen ion conductivity. The part where all the three components of yttria-stabilized zirconia and fuel gas are in contact is the three-phase interface. Therefore, increasing the three-phase interface of the fuel electrode, improving the hydrogen oxidation ability, and improving the output characteristics of the solid oxide fuel cell by efficiently supplying the generated electrons to the external circuit Can do.
In the case of the Ni—YSZ fuel electrode, nickel is present as an oxide, that is, ceramic particles when not in operation, and is reduced to nickel metal during operation.

  Thus, since the size and uniformity of the three-phase interface for both the air electrode and the fuel electrode influence the performance of the fuel cell, the ceramic particles constituting the electrode are sufficiently miniaturized and the particle diameters of each are more uniform. Therefore, it is necessary to make the state excellent in distribution and composition controllability. Therefore, composite ceramic particles having a finer primary particle diameter and uniformly composited at the nanometer level are desired.

  As a method for producing a composite ceramic powder containing a plurality of types of oxides used as an electrode material of a fuel cell, usually a plurality of types of oxide powders are crushed and pulverized using a ball mill, an automatic mortar or the like. In general, a mechanical mixing method in which each powder is stirred and mixed while being pulverized and pulverized to obtain a composite ceramic powder. In addition, a mechanochemical mechanical mixing method having a mechanochemical method for promoting bonding between powders by a thermal action is also used.

  However, the composite ceramic powder obtained by the conventional method is a composite powder in which a plurality of types of primary oxide particles are aggregated and mixed nonuniformly, or a plurality of types of primary oxides. There was a problem that the particles aggregated into a coarse composite powder. Therefore, when such a composite powder is used as a catalyst or an electrode for a fuel cell, there is a problem that the characteristics cannot be sufficiently exhibited.

  Accordingly, as a method for producing a composite ceramic powder that solves these problems and has sufficient characteristics even when used as an electrode for a fuel cell, a plurality of types of metal ions that constitute the composite ceramic powder, such as a solid oxide, are used. For an air electrode raw material powder for a fuel cell, an alkaline solution is added to a solution containing La (lanthanum) ions, Sr (strontium) ions, Mn (manganese) ions, Zr (zirconium) ions and Y (yttrium) ions. A so-called coprecipitation firing method is known in which a neutralized precipitate is produced, and then an oxide is produced by heat-treating the neutralized precipitate to obtain a composite ceramic powder (Patent Document 1, 2).

  In addition, in the air electrode of a solid oxide fuel cell, it has been studied to prevent temporal deterioration of the air electrode by pre-calcining a part of the raw material powder of composite ceramic particles and controlling the particle diameter. (Patent Document 3).

  On the other hand, as a method for producing a composite ceramic powder for a fuel electrode of a solid oxide fuel cell, an oxide powder having a conductivity of oxygen ion made of yttria-stabilized zirconia or samaria-doped ceria, nickel ion or cobalt ion is used. After immersing in the solution containing it, it is dried, and then heat-treated to hold nickel oxide or cobalt oxide on the surface of the oxide powder having oxygen ion conductivity, and this oxide powder further contains nickel or There has been proposed a method for obtaining a target composite ceramic powder by mixing cobalt oxide powder (Patent Document 4).

  Further, a mist pyrolysis method is known as a method having excellent uniformity and composition controllability of composite ceramic powder. For example, a solution containing yttria-stabilized zirconia particles and nickel acetate is misted, and this mist is converted into a mist. A method of obtaining composite particles in which yttria-stabilized zirconia particle groups are unevenly distributed on the surface side of nickel oxide particle groups by heating to a temperature higher than the thermal decomposition temperature of nickel acetate after drying has been proposed (Patent Document 5).

JP 2000-44245 A JP-A-9-86932 JP 2006-40822 A Japanese Patent No. 3565696 Japanese Patent No. 3193294

However, in the case of the coprecipitation firing method shown in Patent Documents 1 and 2, since the composite state of metal ions in the precipitate varies depending on the coprecipitation conditions, the state of formation of each ceramic when the precipitate is heat treated In addition, there was a problem that the characteristics of the composite ceramic particles obtained were difficult to be uniform.
Moreover, even when controlling the particle diameter of the raw material powder of the composite ceramic particle disclosed in Patent Document 3, the control range was a micrometer level.
Further, in the method for producing a composite ceramic powder disclosed in Patent Document 4, although fine particles of nickel or cobalt can be formed on the surface of oxide powder having oxygen ion conductivity, it is retained on the surface. Since there is a limit to the amount of nickel oxide or cobalt oxide to be produced, the controllable range of the composition is narrow, and the composition control itself is difficult.
Further, in the conventional mist pyrolysis method disclosed in Patent Document 5, the uniformity of the distribution of plural types of oxides and the controllability of the composition are improved, but the oxidation in the obtained composite particles There was a problem that the primary particle diameter of the product was large.

  Thus, even if the composite ceramic powder is manufactured using the manufacturing method shown for the electrode of the fuel cell, when it is actually used as the electrode for the fuel cell, the manufactured composite ceramic powder Due to the particle size and composition of the body, there is a problem that sufficient characteristics cannot be obtained.

  The present invention has been made to solve the above problems, and provides a composite ceramic powder excellent in distribution and composition controllability at the nanometer level of a plurality of types of oxide particles, and a method for producing the same. The purpose is to do. In addition, by using the composite ceramic powder of the present invention as an electrode material, there are many three-phase interfaces, and in the air electrode of a solid oxide fuel cell, it has excellent oxygen reducing ability and electronic conductivity, and in the fuel electrode, hydrogen An object of the present invention is to provide a solid oxide fuel cell excellent in oxidizing ability and electronic conductivity.

As a result of intensive studies in order to solve the above problems, the present inventors have found that A _1-x B _x C _1-y D _y O ₃ (where A is selected from the group of La and Sm). One or two elements, B is one or more elements selected from the group of Sr, Ca and Ba, and C is one or more elements selected from the group of Co, Ga and Mn The element, D, is one or more elements selected from the group consisting of Fe, Mg and Ni, and is an oxidation represented by 0.1 ≦ x ≦ 0.5 and 0 ≦ y ≦ 1.0) Or nickel oxide, and zirconia to which oxygen ion conductivity is imparted by solid solution of ions of metal E that can impart oxygen ion conductivity to zirconium oxide by solid solution in zirconium oxide As a zirconia raw material, To produce a basic zirconium carbonate complex, the the basic zirconium carbonate complex, the _{A 1-x B x C 1} -y D y O 3 represented A in order to configure the oxides, B, C and D One or two or more kinds of metal ions or nickel ions selected from the group of the above and metal E ions are co-precipitated to form a precipitate, and this neutralized precipitate is brought to a temperature of 200 ° C. or higher. As a result, it was found that a composite ceramic powder excellent in distribution and composition controllability at the nanometer level of a plurality of types of oxide particles can be easily obtained by heat treatment, and the present invention has been completed.
In addition, by using the composite ceramic powder obtained by the production method of the present invention as an electrode material, an electrode having many three-phase interfaces and excellent in oxygen reduction ability and electron conductivity or hydrogen oxidation ability and electron conductivity can be obtained. It has been found that a solid oxide fuel cell having an improved output and characteristics can be obtained, and the present invention has been completed.

That is, the method for producing the composite ceramic powder of the present invention comprises at least A _1-x B _x C _1-y D _y O ₃ (wherein A is one or two selected from the group of La and Sm). Element, B is one or more elements selected from the group of Sr, Ca and Ba, C is one or more elements selected from the group of Co, Ga and Mn, D is Fe, An oxide or nickel oxide that is one or more elements selected from the group of Mg and Ni, represented by 0.1 ≦ x ≦ 0.5, 0 ≦ y ≦ 1.0), A method for producing a composite ceramic powder comprising zirconia in which ions of a metal E capable of imparting oxygen ion conductivity to zirconium oxide by being dissolved in zirconium oxide are dissolved and oxygen ion conductivity is imparted Zirconium ions and carbonate ions And a first step of forming a basic zirconium carbonate complex by reacting in a basic aqueous solution with the oxide represented by A _1-x B _x C _1-y D _y O ₃ In order to achieve this, a base in which the basic zirconium carbonate complex is formed from one or more metal ions or nickel ions selected from the group of A, B, C and D and the metal E ion An ion of one or more metals selected from the group of A, B, C and D, an ion of the metal E, the basic zirconium carbonate complex, A second step of generating a first precipitate containing a complex salt comprising: or a second precipitate comprising a complex salt comprising the nickel ion, the metal E ion, and the basic zirconium carbonate complex. And the first or A third step of heat treatment in the second precipitate 200 ° C. or higher temperatures, and having a.

In the method for producing a composite ceramic powder of the present invention, at least the oxide represented by A _1-x B _x C _1-y D _y O ₃ and the ions of the metal E are dissolved. A method for producing a composite ceramic powder comprising zirconia to which oxygen ion conductivity is imparted, wherein, in the first step, the zirconium ion and the carbonate ion are mixed with the amount of zirconium ion of 3. The basic zirconium carbonate complex is formed by reacting in the basic aqueous solution containing the carbonate ion amount of 2 times or more and 5.3 times or less, and formed in the second step in the third step. It is preferable that the first precipitate to be heat-treated at a temperature of 200 ° C. or higher.

  Further, in the method for producing a composite ceramic powder of the present invention, the composite ceramic powder comprising nickel oxide and zirconia to which oxygen ion conductivity is imparted by solid dissolution of the metal E ions. The basic aqueous solution containing the amount of the zirconium ion and the carbonate ion in the first step, the amount of the carbonate ion being not less than 0.5 times and not more than 5.3 times the amount of the zirconium ion in the first step. Reacting in to form the basic zirconium carbonate complex, and in the third step, the second precipitate produced in the second step is heat-treated at a temperature of 200 ° C. or higher. preferable.

  It is preferable that pH of the basic aqueous solution is 7 or more and 9 or less.

  The composite ceramic powder of the present invention is obtained by the method for producing a composite ceramic powder of the present invention.

  The solid oxide fuel cell of the present invention is characterized by using the composite ceramic powder of the present invention as an electrode material.

According to the manufacturing method of a composite ceramic powder of the present invention, an oxide or nickel oxide expressed by at least _{A 1-x B x C 1} -y D y O 3, oxides by solid solution in the zirconium oxide A method for producing a composite ceramic powder comprising zirconia in which ions of metal E capable of imparting oxygen ion conductivity to zirconium are dissolved and oxygen ion conductivity is imparted. And carbonate ions are reacted in a basic aqueous solution to form a basic zirconium carbonate complex, and then an oxide represented by A _1-x B _x C _1-y D _y O ₃ is formed. Therefore, one or more kinds of metal ions or nickel ions selected from the group of A, B, C and D, and the ions of the metal E are formed into the basic zirconium carbonate complex. By adding to the basic aqueous solution, ions of one or more metals selected from the group of A, B, C and D, ions of the metal E, and the basic zirconium carbonate A first precipitate containing a complex salt consisting of a complex, or a second precipitate containing a complex salt consisting of the nickel ion, the metal E ion, and the basic zirconium carbonate complex, Next, since the first or second precipitate is heat-treated at a temperature of 200 ° C. or higher, it is excellent in nanometer level distribution and composition controllability in a plurality of types of oxide particles, and solid oxidation. When applied to physical fuel cells, composite ceramic powders that have many three-phase interfaces and can form electrodes with excellent oxygen reducing ability and electronic conductivity, or hydrogen oxidizing ability and electronic conductivity. It can be obtained easily and inexpensively.

  In addition, according to the composite ceramic powder of the present invention, since it is obtained by the method for producing a composite ceramic powder of the present invention, the nanometer level distribution and composition controllability in a plurality of types of oxide particles are excellent, When applied to a solid oxide fuel cell, it is possible to provide a composite ceramic powder capable of forming an electrode excellent in oxygen reduction ability and electron conductivity, or hydrogen oxidation ability and electron conductivity. .

  Further, according to the solid oxide fuel cell of the present invention, since the composite ceramic powder of the present invention is used as an electrode material, a fuel electrode having a wide three-phase interface and excellent oxygen reduction ability and electronic conductivity, Or the air electrode excellent in hydrogen oxidation ability and electronic conductivity can be formed, As a result, the output and characteristic of a battery can be improved.

It is a schematic diagram which shows the electrochemical property evaluation apparatus for evaluating the electrode of the solid oxide fuel cell of one Embodiment of this invention. It is a powder X-ray-diffraction (XRD) pattern of the composite ceramic powder of Example 1 of this invention. It is a transmission electron microscope image of the composite ceramic powder of Example 1 of this invention. It is a powder X-ray-diffraction (XRD) pattern of the composite ceramic powder of Example 2 of this invention. It is a powder X-ray-diffraction (XRD) pattern of the composite ceramic powder of Example 3 of this invention.

  The best mode for carrying out the method for producing composite ceramic powder and the solid oxide fuel cell of the present invention will be described. This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

Here, in order to simplify the following description, it is selected from the group of A, B, C, and D to constitute an oxide represented by A _1-x B _x C _1-y D _y O _3. One or more elements and nickel may be collectively referred to as “element M”. Similarly, one or more metal ions and nickel ions selected from the group of A, B, C, and D may be collectively referred to as element M ions.
Further, in the following description, “ion of metal E that can give oxygen ion conductivity to zirconium oxide by dissolving in zirconium oxide” is referred to as “ion of metal E”, and similarly, This metal is called “Metal E”.

Furthermore, the “zirconia imparted with oxygen ion conductivity by the solid solution of metal E ions” in this application may be referred to as “oxygen ion conductive zirconia”.
In the following description, “zirconia” is not only zirconium oxide but also zirconium oxide containing zirconium oxide as a main component and various metals in solid solution, for example, zirconium oxide whose oxygen ion conductivity is improved by solid solution of metal ions. Shall be included. On the other hand, “zirconium oxide” means only an oxide of zirconium that does not contain an intentional additive.
In the following description, “zirconium ions” include not only zirconium ions (Zr ⁴⁺ ) but also oxyzirconium ions (ZrO ²⁺ ). This is because it is difficult to specify which state of zirconium is in the solution and the complex salt.

[Production method of composite ceramic powder]
The method for producing a composite ceramic powder of the present invention includes an oxide or nickel oxide represented by at least A _1-x B _x C _1-y D _y O ₃ and oxygen ion conductive zirconia (ion of metal E is present). Zirconia imparted with oxygen ion conductivity by solid solution), and firstly, zirconium ions and carbonate ions are reacted in a basic aqueous solution. To form a basic zirconium carbonate complex, and then to form an oxide represented by the ions of the element M (the A _1-x B _x C _1-y D _y O ₃ , A, B, C And one or more metal ions or nickel ions selected from the group of D) and metal E ions are added to the basic aqueous solution in which the basic zirconium carbonate complex is formed. The first precipitate containing a complex salt comprising one or more metal ions selected from the group of A, B, C and D, a metal E ion, and a basic zirconium carbonate complex Or generating a second precipitate containing a complex salt composed of nickel ions, metal E ions, and a basic zirconium carbonate complex, and then heat-treating the precipitate at a temperature of 200 ° C. or higher. Is a manufacturing method characterized by

  Here, the “basic zirconium carbonate complex” refers to a zirconium carbonate complex produced in a neutral or basic solution in the method for producing a composite ceramic powder of the present invention, as will be described later. In this specification, the term basic zirconium carbonate complex is used in order to distinguish from a normal zirconium carbonate complex.

In the present invention, the basic zirconium carbonate complex, which is an anion formed first, is reacted with ions of element M and metal E, which are cations, to form a complex salt precipitate. It is. Since this precipitate is a complex salt, that is, a chemical reaction product, the ions of the element M and the ions of the metal E and the zirconium ions form a mixed state at the atomic level. If an oxide is obtained by heat-treating the first or second precipitate thus obtained, an oxide in which element M, metal E, and zirconium are mixed at an atomic level can be obtained. become.
Even if phase separation occurs during the heat treatment, if the heat treatment conditions are controlled, aggregation and growth of each phase separated can be suppressed. As a result, the oxide formed by the element M and the metal E It is possible to obtain a composite ceramic powder in which the zirconia in which the ions are dissolved is mixed in a nanometer size.

  Further, since the obtained precipitate is a complex salt, that is, a reactive organism, the composition ratio thereof is constant, and the composition ratio of the element M, the metal E, and zirconium does not vary in the precipitate. That is, a composite ceramic powder having a stable composition ratio and no variation in characteristics can be obtained.

In the present invention, the basic zirconium carbonate complex is first formed for the following reason.
As a method for producing a composite ceramic powder similar to the present invention, by adding zirconium ion, element M ion and metal E ion simultaneously to a basic solution containing carbonate, the element M ion, There is a method of obtaining a precipitate containing a complex salt composed of a metal E ion and a basic zirconium carbonate complex. In this method, the basic zirconium carbonate complex can be obtained because the production rate of the basic zirconium carbonate complex is faster than the production rate of oxides, hydroxides, etc. of zirconium, element M and metal E. This is probably because a basic zirconium carbonate complex is formed.

  However, in this method, since the formation of the basic zirconium carbonate complex and the formation of the precipitate are not performed in a clear step, the product is formed before the basic zirconium carbonate complex is completely formed. There is a risk of precipitation. In a state where the basic zirconium carbonate complex is not completely formed, the valence as the anion of the complex is not constant, and the cation bonded to the complex as a complex salt, that is, the ion of the element M and the metal E Variations in the amount of ions occur. For this reason, although the uniformity of the composition in the formed precipitate is improved as compared with the case where no basic zirconium carbonate complex is formed, it cannot always be said to be in a good state.

On the other hand, in the method for producing a composite ceramic powder of the present invention, a basic zirconium carbonate complex is formed in advance, and after this complex becomes stable, ions of the element M as a cation or metal E To form a precipitate. As a result, the distribution and composition ratio of the components in the obtained precipitate are more uniform. As a result, in the composite ceramic powder obtained by heat-treating the precipitate, each component, that is, A _{1-1 x B x C 1-y D} y O 3 oxide represented, nickel oxide, oxygen ion conductivity of zirconia, it is also a smaller one of the crystallite _{diameter, a 1-x B x} C _A composite ceramic powder excellent in uniformity between the oxide represented by _1-y D _y O ₃ and oxygen ion conductive zirconia or between nickel oxide and oxygen ion conductive zirconia can be obtained.

"Composite ceramic powder"
First, the composite ceramic powder produced by the production method of the present invention will be described.
Composite ceramic powder is produced by the production method of the present _{invention, A 1-x B x C} 1-y D y and oxide represented by O _3, oxygen ion conductive zirconia and composite ceramic powder formed by Or a composite ceramic powder (composite ceramic powder Y) formed of nickel oxide and oxygen ion conductive zirconia.

First, as an oxide represented by A _1-x B _x C _1-y D _y O _3, an oxide having a perovskite crystal structure is preferable, and A is selected from the group of La and Sm. 1 or 2 elements, B is one or more elements selected from the group of Sr, Ca and Ba, C is one or more elements selected from the group of Co, Ga and Mn And D is one or more elements selected from the group of Fe, Mg and Ni, and x and y are 0.1 ≦ x ≦ 0.5 and 0 ≦ y ≦ 1.0, respectively. It has a range.

Moreover, as zirconia (oxygen ion conductive zirconia) to which oxygen ion conductivity is imparted by solid solution of ions of metal E, yttrium oxide, samarium oxide, scandium oxide, calcium oxide, magnesium oxide with respect to zirconium oxide. One or two or more components selected from the above are dissolved, and the amount of the solid solution is more than 0% and less than 30%, more preferably more than 0.03% in molar percentage with respect to zirconium oxide. It shows less than 20%. Zirconium oxide in which yttrium oxide or the like is dissolved is also referred to as stabilized zirconia and has excellent mechanical characteristics. From this point, the characteristics are improved.
The number of moles of the solid solution component is the number of moles as an oxide, not the number of moles as an ion of metal E. For example, in the case of yttrium oxide, it is the number of moles as Y ₂ O ₃ and not the number of moles as Y ³⁺ .

The ratio of the composite ceramic powder X made by the production method of the present _invention, the oxide represented by _{A 1-x B x C 1} -y D y O 3, the oxygen ion conductive zirconia, _{A 1 -x B x C 1-y D} y O 3 Lw mass of the oxide represented by the mass of the oxygen ion conductive zirconia as Zw, the mass ratio of each component, is (Lw / Zw), 0. Preferably it is greater than 11 and less than 9.
The ratio of nickel oxide to oxygen ion conductive zirconia in the composite ceramic powder Y produced by the manufacturing method of the present invention is such that the mass of nickel oxide is Nw and the mass of oxygen ion conductive positive zirconia is Zw. The mass ratio (Nw / Zw) of these components is preferably in the range of more than 0.21 and less than 17.2.

The reason for the composite ceramic powder of the present invention, an oxide or nickel oxide represented by _{A 1-x B x C 1} -y D y O 3, the ratio of the oxygen ion conductivity of zirconia in the range of the In the heat treatment in the production method of the present invention, at a ratio outside the above range, either one of oxide or nickel oxide and oxygen ion conductive zirconia is excessively present. This is because fusion and grain growth between each other easily proceed, and a composite ceramic powder in which fine particles are uniformly dispersed cannot be obtained. This is because when such a composite ceramic powder is used to form an electrode of a solid oxide fuel cell, good electrode characteristics cannot be obtained.
Further, in the composite ceramic powder Y, when the nickel oxide is too small relative to the oxygen ion conductive zirconia, the conductivity in the fuel electrode of the solid oxide fuel cell formed using the obtained composite ceramic powder is low. This is because good electrode characteristics cannot be obtained.

"Preparation of basic zirconium carbonate complex"
In the production method of the present invention, a basic zirconium carbonate complex is first formed. This basic zirconium carbonate complex is an anionic complex formed by coordination of carbonate ions (CO ₃ ²⁻ ) and hydroxyl groups (OH) to zirconium ions. However, the composition is not clear, and [ZrO (CO ₃ ) _k (OH) _l ] ^{(2k + 1−2) −} or [Zr (CO ₃ ) _m (OH) _n ] ^{(2m + n−4) −} It is described as follows.

For example, the following method is shown as a method for preparing a basic zirconium carbonate complex, and a solution of carbonate (hereinafter, basic carbonate) in which the solution is basic is added to a solution containing zirconium ions. (Materials Research Bulletin 2002, 37, 1933-1940).
As the basic carbonate solution, sodium carbonate (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), sodium hydrogen carbonate (NaHCO ₃ ), potassium hydrogen carbonate (KHCO ₃ ), ammonium carbonate ((NH ₄ ) ₂ An aqueous solution of CO ₃ ), ammonium hydrogen carbonate (NH ₄ HCO ₃ ), or the like can be used. Among these, an aqueous solution of (NH ₄ ) ₂ CO ₃ or NH ₄ HCO ₃ containing ammonium ions can be preferably used. This is because when metal ions such as Na ⁺ and K ⁺ ions in the alkali carbonate remain in the precipitate, these metal ions remain in the obtained composite ceramic powder, and finally the solid oxide fuel obtained This is because the battery characteristics may be adversely affected.
The concentration in the basic carbonate solution is not particularly limited, but is preferably in the range of 0.1 mol% to 5 mol% from the viewpoint of productivity and handling.

In order to allow the basic zirconium carbonate complex to exist stably, the pH of the solution in which the basic zirconium carbonate complex is dissolved is preferably 7 or more, that is, neutral to alkaline. When the solution is acidic, a basic zirconium carbonate complex is not formed, and as a result, ions of element M (one or more metal ions selected from the group of A, B, C and D and nickel ions) Then, there is a possibility that a precipitate containing a complex salt composed of ions of metal E and a basic zirconium carbonate complex may not be stably formed.
Also, when the pH of the solution is higher than 12, zirconium precipitates as carbonates or hydroxides, again from the ions of element M, the ions of metal E, and the basic zirconium carbonate complex. There is a possibility that a precipitate containing the complex salt is not stably formed.
Furthermore, there is a possibility that the composition of the basic zirconium carbonate complex varies due to the variation in pH of the solution in which the basic zirconium carbonate complex is dissolved.
From these facts, in order to allow the basic zirconium carbonate complex to exist stably, it is preferable to keep the pH of the liquid constant at 7 or more and 12 or less, including during subsequent precipitation.

As a method for keeping the pH constant, an alkaline solution may be added because a solution containing zirconium ions is usually acidic. That is, when adding a solution containing zirconium ions to a basic carbonate solution, an alkaline solution may be added simultaneously. The alkaline solution is not particularly limited, but it is preferable to use aqueous ammonia because a strong alkaline solution makes it difficult to keep the pH constant and does not contain metal ions. A combination of ammonia water and the above (NH ₄ ) ₂ CO ₃ or NH ₄ HCO ₃ is more preferable because it has a buffer effect of keeping the pH of the aqueous solution constant.

Next, the ratio between the amount of zirconium ions and the amount of carbonate ions varies depending on the type of composite ceramic powder to be manufactured. In the method for manufacturing the composite ceramic powder X, the amount of zirconium ions is 3.2 times or more and 5.3. It is preferable to use a carbonate ion amount that is twice or less.
Here, the reason why the carbonate ion amount in the basic aqueous solution is 3.2 times or more and 5.3 times or less the zirconium ion amount is selected from the group of A, B, C, and D in a later step. When one or more kinds of metal ions and metal E ions are added, the composition of the first precipitate produced varies depending on the ratio of the carbonate ion amount and the zirconium ion amount, This is because a precipitate having the desired composition cannot be obtained if it is removed.

Here, when the abundance in the first precipitate relative to the abundance in the raw material solution of each component is defined as a yield, when the amount of carbonate ions is less than 3.2 times the amount of zirconium ions, the metal B, The yield of components C and D is less than 85%, and the ratio of each component of metals A, B, C, and D in the first precipitate is represented by A _1-x B _x C _1-y D _y O ₃ This is not preferable because the composition ratio deviates from that for forming the oxide.
Moreover, when the carbonate ion amount exceeds 5.3 times the zirconium ion amount, the yield of zirconium is less than 75%, and the oxygen ion conductive zirconia amount and A _{1 in the} finally obtained composite ceramic powder. ratio of amount of oxide represented by _{-x B x C 1-y D} y O 3 is, since deviates from the ratio of interest, is not preferred.
Considering the yield of these metal B, C and D components and the yield of zirconium, the amount of carbonate ions in the basic aqueous solution is 3.3 times or more and 4.6 times or less of the amount of zirconium ions. It is more preferable that it is 3.4 times or more and 4.0 times or less.

  In addition, about A component and the metal E, since the abundance in a precipitate will be 95% or more in raw material aqueous solution irrespective of the ratio of the carbonate ion amount in a basic aqueous solution, and a zirconium ion amount, these components There is no restriction on the amount of carbonate ions and the amount of zirconium ions.

Moreover, it is preferable to adjust the ratio of each ion mixed in this manufacturing method so that the composition of the composite ceramic powder X finally obtained may become the said suitable range. That is, it is represented by A _1-x B _x C _1-y D _y O ₃ finally formed from ions of one or more metals selected from the group of A, B, C, and D. When the mass of the oxide is Lw and the mass of the oxygen ion conductive zirconia finally formed from the metal E ion and the zirconium ion is Zw, the mass ratio of these components, (Lw / Zw), The amount of each ion is preferably selected so that it exceeds 0.11 and is less than 9.
Furthermore, the ratio of metal E ions to zirconium ions for forming oxygen ion conductive zirconia is the molar amount Em obtained by converting metal E ions into oxide and the molar amount obtained by converting zirconium ions into oxide. It is preferable to select such that the ratio (Em / Zm) with Zm is greater than 0 and less than 0.3.

By setting the amount of each ion within this range, composite ceramic particles in which oxide particles represented by A _1-x B _x C _1-y D _y O ₃ are combined in oxygen ion conductive zirconia particles Alternatively, composite ceramic particles X in which oxygen ion conductive zirconia particles are combined in oxide particles represented by A _1-x B _x C _1-y D _y O ₃ are freely controlled and produced. Can do.

On the other hand, as the ratio of the zirconium ion amount and the carbonate ion amount in the method for producing the composite ceramic powder Y, it is preferable to use a carbonate ion amount that is 0.5 to 5.3 times the zirconium ion amount.
Here, the reason why the amount of carbonate ions in the basic aqueous solution is 0.5 to 5.3 times the amount of zirconium ions is that the composition of the second precipitate to be generated is the amount of carbonate ions and the amount of zirconium ions. This is because the second precipitate having the desired composition cannot be obtained if the ratio is outside this range.

That is, when the carbonate ion amount is less than 0.5 times the zirconium ion amount, the nickel yield is less than 75%, while when the carbonate ion amount exceeds 5.3 times the zirconium ion amount, Since the precipitation state of zirconium and nickel becomes difficult to control, the ratio between the amount of oxygen ion conductive zirconia and the amount of nickel oxide in the finally obtained composite ceramic powder Y is determined from the target ratio. Since it will shift | deviate, it is not preferable.
In view of the yield of nickel and the yield of zirconium, the carbonate ion amount in the basic aqueous solution is more preferably 0.8 times or more and 4.6 times or less the zirconium ion amount. More preferably, it is 0 times or more and 3.6 times or less.

  For metal E, the yield is 95% or more regardless of the ratio of the carbonate ion amount and the zirconium ion amount in the basic aqueous solution. There is no.

Moreover, it is preferable to adjust the ratio of each ion mixed in this manufacturing method so that the composition of the composite ceramic powder Y finally obtained may become the said suitable range. The mass of nickel oxide finally formed from nickel ions is Nw, and the mass of oxygen ion conductive zirconia finally formed from metal E ions and zirconium ions is Zw. The amount of each ion is preferably selected so that the ratio, (Nw / Zw) is greater than 0.21 and less than 17.2.
Furthermore, the ratio of metal E ions to zirconium ions for forming oxygen ion conductive zirconia is the molar amount Em obtained by converting metal E ions into oxide and the molar amount obtained by converting zirconium ions into oxide. It is preferable to select such that the ratio (Em / Zm) with Zm is greater than 0 and less than 0.3.

  By setting the amount of each ion within this range, oxygen ion conductive zirconia particles are combined with nickel oxide composite ceramic particles or oxygen oxide conductive zirconia particles are combined with nickel oxide particles. The composite ceramic particles Y can be freely controlled and produced.

"Precipitation"
In the solution containing the basic zirconium carbonate complex adjusted as described above, the ions of the element M and the ions of the metal E are maintained in a state where the pH of the solution is kept constant in the range of 7 or more and 9 or less. Add a solution containing both. Thereby, the 1st or 2nd deposit containing the complex salt which consists of the ion of element M, the ion of metal E, and a basic zirconium carbonate complex can be obtained.
In addition, when the ions of the element M and the ions of the metal E are added separately, there is a possibility that the composition of the ions of the element M and the ions of the metal E may vary in the obtained precipitate. It is preferable to add a solution containing both ions.

Here, the reason why the pH of the aqueous solution after addition is kept constant at 7 or more is to keep the basic zirconium carbonate complex in a stable state. The reason why the pH of the aqueous solution after addition is 9 or less is that when the pH exceeds 9, the ions of the added element M precipitate as hydroxides, and the first or second precipitation with a uniform composition. This is because there is a possibility that a product cannot be obtained.
As a method for keeping the pH constant, an alkaline solution may be added because the solution containing the ions of the element M to be added and the ions of the metal E is acidic. However, in the case of a strongly alkaline solution, the pH may be kept constant. Since it becomes difficult and it is preferable not to contain a metal ion, it is preferable to use aqueous ammonia. A combination of ammonia water and the above (NH ₄ ) ₂ CO ₃ or NH ₄ HCO ₃ is more preferable because it has a buffer effect of keeping the pH of the aqueous solution constant.

Here, the mass ratio (CO ₃ ²⁻ / Zr) between the amount of carbonate ions and the amount of zirconium contained in the first or second precipitate is preferably 0.07 or more and 3.6 or less.
The mass ratio (CO ₃ ²⁻ / Zr) between the amount of carbonate ions and the amount of zirconium contained in the first or second precipitate is the amount of zirconium ions and carbonate ions (CO ₃ ²⁻ ) ^{Depending on the} amount and pH of the liquid, that is, the amount of hydroxide ions (OH ⁻ ), a stable precipitation product can be formed within the above range. Therefore, a composite ceramic powder having good characteristics can be obtained by heat-treating the first or second precipitate at 200 ° C. or higher.

The precipitate containing the complex salt composed of the element M ion, the metal E ion, and the basic zirconium carbonate complex thus obtained is subjected to alkali filtration by a normal filtration washing method using pure water. After removing and washing impurity ions such as ions and halogen ions, drying is performed at a temperature of less than 200 ° C., more preferably 150 ° C. or less, using a dryer or the like to obtain a dried product. The precipitate after washing with pure water may be washed with a volatile organic solvent such as alcohol to speed up drying.
The reason why the drying temperature is limited to less than 200 ° C. is that when the temperature is 200 ° C. or more, the precipitate is thermally decomposed and there is no difference from the next heat treatment step. The temperature may be raised as it is, and drying and heat treatment may be continuously performed, or the temperature may be gradually increased during the heat treatment and replaced with the drying step.

"Heat treatment of precipitate"
The resulting dried product, for example, by using an electric furnace or the like, in the atmosphere, 200 ° C. or higher and 1000 ° C. or less, preferably by heat treatment at 500 ° C. or higher and 1000 ° C. or less of the _{temperature, A 1-x} oxide particles represented by _{B x C 1-y D y} O 3 or the nickel oxide particles, composed of an oxygen ion-conductive zirconia particles, composite ceramic powder (composite ceramic powder X or composite ceramic powder, Y) can be produced.

Here, the reason for limiting the heat treatment temperature to 200 ° C. or higher is that when the temperature is lower than 200 ° C., generation of oxygen ion conductive zirconia particles from zirconium and metal E contained in the dried product, and also in the precipitated dried product included a, B, generation or precipitation of oxide particles represented by _{a 1-x B x C 1} -y D y O 3 from one or more elements selected from the group of C and D This is because the generation of nickel oxide particles from nickel contained in the dried product becomes insufficient.
When the generation of these oxide particles, that is, oxygen ion conductive zirconia particles and oxide particles or nickel oxide particles represented by A _1-x B _x C _1-y D _y O ₃ is insufficient, oxygen an ion conductive zirconia particles, the _{a 1-x B x C 1} -y D y O 3 oxide fine particles or composite ceramic particles which nickel oxide fine particles are composite represented, can not be freely controlled manufacturing Because.

  In addition, when the heat treatment temperature exceeds 1000 ° C., grain growth and sintering of each component in the formed composite ceramic powder occur, so that the crystallite size of each component increases and the uniformity in the powder. This is because, when the electrode of the solid oxide fuel cell is formed, good characteristics cannot be obtained.

[Solid oxide fuel cell]
The solid oxide fuel cell of the present invention uses the composite ceramic powder obtained by the method for producing a composite ceramic powder of the present invention as an electrode material.

First, the relationship between the composite ceramic powder obtained by the composite ceramic powder manufacturing method of the present invention and the electrode of the solid oxide fuel cell will be described.
First, a composite ceramic powder X containing oxide particles represented by A _1-x B _x C _1-y D _y O ₃ and oxygen ion conductive zirconia particles is used as an air electrode of a solid oxide fuel cell. It can be suitably used as a material. The reason is that the electrode material using this composite ceramic powder X is excellent in oxygen reducing ability and electron conductivity, and can efficiently perform an ionization reaction between electrons and oxygen gas supplied from an external circuit. What can be done. Therefore, when the composite ceramic powder X is used as a material for forming the air electrode, the amount of oxygen ionization at the air electrode can be increased, and the generated oxygen ions can be efficiently supplied to the electrolyte. And the characteristics can be improved.

In this composite ceramic powder X, oxide particles represented by A _1-x B _x C _1-y D _y O ₃ and oxygen ion conductive zirconia particles were dispersed in a nanometer size. Since it is a composite particle, the oxide particles represented by A _1-x B _x C _1-y D _y O ₃ can be fused at the operating temperature during power generation of the solid oxide fuel cell. This is because grain growth can be suppressed, so that a solid oxide fuel cell having a large amount of three-phase interface, oxygen reducing ability, electronic conductivity, and an excellent air electrode can be provided.

  Next, the composite ceramic powder Y containing nickel oxide particles and oxygen ion conductive zirconia particles can be suitably used as a fuel electrode material of a solid oxide fuel cell. The reason is that the electrode material using this composite ceramic powder can increase the amount of electrons generated, so that electrons can be efficiently supplied to the external circuit and the output characteristics can be improved. Is mentioned.

  Further, since this composite ceramic powder Y is a composite particle in which nickel oxide particles and oxygen ion conductive zirconia particles are dispersed in a nanometer size, a reducing atmosphere during power generation of this solid oxide fuel cell Even when nickel oxide is subjected to reduction metallization, it is possible to suppress fusion and grain growth of the generated nickel metal fine particles, so there is a large amount of three-phase interface, hydrogen oxidation ability and electronic conductivity. This is because a solid oxide fuel cell having an excellent fuel electrode can be provided.

Next, as a method for producing an electrode of a solid oxide fuel cell, a generally used method may be used. For example, the composite ceramic powder is mixed with a binder such as polyethylene glycol or polyvinyl butyral. The obtained paste may be applied to the surface of a solid electrolyte substrate made of yttria stabilized zirconia or the like by a printing method or the like to form a film, and then fired in an oxidizing atmosphere, for example, in air.
The firing temperature is in the range of 700 ° C. to 1400 ° C. when the air electrode, that is, the composite ceramic powder X is used, and on the other hand, in the case of using the fuel electrode, ie, the composite ceramic powder Y, in the range of 1200 ° C. to 1500 ° C. Can be selected within.

FIG. 1 is a schematic diagram showing an electrochemical characteristic evaluation apparatus, which is an apparatus for measuring the electric characteristics of an electrode of a solid oxide fuel cell.
In the figure, reference numeral 1 is an electrolyte such as yttria-stabilized zirconia, reference numeral 2 is a reference electrode made of platinum (Pt), reference numeral 3 is formed on the upper surface of the electrolyte 1, and the composite ceramic powder X is used in the above embodiment. The air electrode produced by using the reference electrode 2 is formed on the lower surface of the reference electrode 2, and the fuel electrode produced using the composite ceramic powder Y in the above embodiment, and the code 5 is produced by using the air electrode 3 and the fuel electrode 4, respectively. A platinum mesh disposed on the top, a reference numeral 6 is a glass seal, a reference numerals 7 and 8 are coaxially arranged alumina tubes having different diameters, a reference numeral 9 is a platinum wire, a reference numeral 10 is dry air, and a reference numeral 11 is 3%. It is a humidified hydrogen gas having a composition of H ₂ O-97% H ₂ .

Here, in order to measure the electrode reaction resistance of the air electrode 3 of the solid oxide fuel cell, the air electrode 3 and the platinum net 5 are sequentially attached to the upper surface of the electrolyte 1, and the fuel electrode 4 is attached to the lower surface of the reference electrode 2. And the platinum net 5 are sequentially attached, the dry air 10 is supplied to the air electrode 3, and the humidified hydrogen gas 11 is supplied to the fuel electrode 4, while the air electrode 3 and the reference electrode 2 in the temperature range of 600 ° C. to 800 ° C. The AC impedance is measured using the fuel electrode 4 as a counter electrode.
Further, in order to measure the electrode reaction resistance of the fuel electrode 4, the AC impedance between the fuel electrode 4 and the reference electrode 2 is measured with the air electrode 3 as a counter electrode by the same method as the measurement of the air electrode 3.

  The composite ceramic powder obtained by the composite ceramic powder manufacturing method of the present invention can be applied to both the air electrode and the fuel electrode of a solid oxide fuel cell, but this embodiment is limited to this form. The composite ceramic powder obtained by the present invention may be used for only one of the air electrode and the fuel electrode, and a conventional material may be used for the counterpart electrode. This is because the composite ceramic powder obtained by the present invention can improve the characteristics of both the air electrode and the fuel electrode, so that the effect of using only one of them is sufficient. Of course, it is preferable to use it for both electrodes because the characteristics can be further improved.

As described above, according to the manufacturing method of a composite ceramic powder of the present invention, an oxide or nickel oxide expressed by at least _{A 1-x B x C 1} -y D y O 3, metal E A method for producing a composite ceramic powder comprising zirconia to which oxygen ion conductivity is imparted by solid solution of ions, wherein first, zirconium ions and carbonate ions are mixed in a basic aqueous solution. A group of A, B, C and D to react to form a basic zirconium carbonate complex and then constitute the oxide represented by said A _1-x B _x C _1-y D _y O ₃ 1 or two or more kinds of metal ions or nickel ions selected from the above and the ions of metal E are added to the basic aqueous solution in which the basic zirconium carbonate complex is formed, whereby A, B , And a precipitate containing a complex salt consisting of one or more metal ions selected from the group of D, the metal E ion, and the basic zirconium carbonate complex, or the nickel ion, A precipitate containing a complex salt composed of the metal E ion and the basic zirconium carbonate complex is generated, and then the precipitate is heat-treated at a temperature of 200 ° C. or more, so that a plurality of types of oxides are formed. In addition to excellent particle size distribution and composition controllability in particles, when applied to a solid oxide fuel cell, there are many three-phase interfaces, oxygen reduction ability and electron conductivity, or hydrogen oxidation ability and electron. A composite ceramic powder capable of forming an electrode having excellent conductivity can be obtained easily and inexpensively.

  Further, according to the composite ceramic powder of the present invention, since it is obtained by the method for producing a composite ceramic powder of the present invention, it is excellent in distribution and composition controllability at a nanometer level in a plurality of types of oxide particles, and solid When applied to an oxide fuel cell, it is possible to provide a composite ceramic powder capable of forming an electrode excellent in oxygen reduction ability and electron conductivity, or hydrogen oxidation ability and electron conductivity.

  According to the solid oxide fuel cell of the present invention, since the composite ceramic powder of the present invention is used as an electrode material, an electrode excellent in oxygen reduction ability and electron conductivity or hydrogen oxidation ability and electron conductivity. As a result, the output and characteristics of the battery can be improved.

  That is, according to the present invention, a composite ceramic powder that can be suitably used as an electrode of a solid oxide fuel cell can be obtained, and characteristics of a solid oxide fuel cell using the composite ceramic powder can be improved. Therefore, its utility value is great in various industrial fields including solid oxide fuel cells.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.
In the following description, yttrium ion solid solution zirconia formed from a solution is described as “YSSZ” and is distinguished from “YSZ” of conventional yttria-stabilized zirconia.

"Example 1"
To 178 g of pure water, 6.64 g of ammonium hydrogen carbonate (NH ₄ HCO ₃ , manufactured by Kanto Chemical Co., Ltd.) was dissolved to prepare a pH 8 basic ammonium hydrogen carbonate aqueous solution A-1.
Then, the pure water 250 g, of zirconium chloride oxide octahydrate (ZrOCl ₂ · _{8H 2} O, manufactured by Kanto Chemical Co., Inc.) was dissolved 9.21 g, was prepared zirconium ion aqueous solution B-1.
Next, to pure water 450 g, nickel nitrate hexahydrate (Ni (NO ₃ ) ₂ .6H ₂ O, manufactured by Kanto Chemical) 30.81 g and yttrium nitrate hexahydrate (Y (NO ₃ ) ₃ · 6H ₂ O, manufactured by Kanto Chemical Co., Ltd.) 2.09 g was dissolved to prepare an aqueous solution C-1 containing nickel ions and yttrium ions as metal E ions.
Note that the amount of carbonate ions contained in the aqueous solution A-1 is 2.95 times the amount of zirconium ions contained in the aqueous solution B-1.
The mass ratio of the oxide finally obtained by this example, that is, nickel oxide (NiO) and yttrium ion solid solution zirconia (YSSZ) is NiO: YSSZ = 0.65: 0.35. It has been established.

Next, the aqueous solution of ammonium hydrogen carbonate A-1 was added with the aqueous solution of zirconium ion B-1 while maintaining the pH at 8 by simultaneously adding aqueous ammonia (12.5% by mass as NH ₃ , manufactured by Kanto Chemical). By mixing, a basic zirconium carbonate complex-containing aqueous solution D-1 was prepared.
Here, since precipitation did not generate | occur | produce in the aqueous solution D-1, it confirmed that the basic zirconium carbonate complex was formed.

Next, a precipitate E-1 was prepared by adding and mixing the aqueous solution C-1 while maintaining the pH at 8 by simultaneously adding aqueous ammonia to the basic zirconium carbonate complex-containing aqueous solution D-1. .
Next, the obtained precipitate E-1 was washed with water several times with a suction filtration washing device to remove impurity ions, and then the solvent was replaced with ethanol, followed by drying at 80 ° C. for 24 hours in a dryer. The dried product F-1 was obtained. Next, the obtained dried product F-1 was pulverized in a mortar and heat-treated at 800 ° C. or 1000 ° C. in an electric furnace, and the nickel oxide (NiO) -yttrium ion solid solution zirconia (YSSZ) composite of Example 1 was used. Ceramic powder G-1 was obtained.

Subsequently, 1.5 g of the composite ceramic powder G-1 (G-1B) obtained by heat-treating the dried product F-1 at 1000 ° C. for 6 hours, 0.5 g of polyethylene glycol (molecular weight: 400, manufactured by Kanto Chemical) and ethanol This was mixed with 10 g in a ball mill, and then this mixed solution was heated to 80 ° C. to evaporate and remove ethanol to prepare NiO—YSSZ paste H-1.
Next, this paste H-1 was applied by screen printing onto the surface of an 8 mol% yttria-stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, which is a solid electrolyte, and then baked at 1300 ° C. for 2 hours to obtain an 8YSZ substrate. A fuel electrode I-1 made of the composite ceramic powder G-1B was formed thereon.

Next, 1.5 g of commercially available lanthanum strontium manganate (La _0.8 Sr _0.2 MnO ₃ , LSM, manufactured by AGC Seimi Chemical) powder was ball milled together with 0.5 g of polyethylene glycol (molecular weight: 400) and 10 g of ethanol. Then, this mixed solution was heated to 80 ° C. to evaporate and remove ethanol to prepare an LSM paste.
This LSM paste was applied by screen printing on the back surface of the 8YSZ substrate on which the fuel electrode I-1 was formed, and then baked at 1100 ° C. for 2 hours to form the air electrode K-1 on the back surface of the 8YSZ substrate. . Further, a platinum wire was wound around the side surface of the 8YSZ substrate to form a reference electrode, and the solid oxide fuel cell of Example 1 was formed.

"Example 2"
Aqueous ammonium hydrogen carbonate solution A-2 was prepared by dissolving 9.75 g of ammonium hydrogen carbonate in pure water and further adding aqueous ammonia to adjust the pH to 8 and making the total amount of the aqueous solution 241.75 g.
Next, 11.13 g of zirconium chloride octahydrate was dissolved in 170 g of pure water to prepare an aqueous zirconium ion solution B-2.
Then, the pure water 250 g, yttrium nitrate hexahydrate 2.09 g, lanthanum nitrate hexahydrate _{(La (NO 3) 3 ·} 6H 2 O, manufactured by Kanto Chemical) 7.48 g, strontium nitrate (Sr (NO _{3) 2,} manufactured by Kanto Kagaku) 0.92 g and manganese nitrate hexahydrate _{(Mn (NO 3) 2 ·} 6H 2 O, dissolved Kanto Chemical) 6.32 g, and yttrium ions as metal E ions, An aqueous solution C-2 containing lanthanum ions, strontium ions, and manganese ions as ions for forming A _1-x B _x C _1-y D _y O ₃ was prepared.
The amount of carbonate ions contained in the aqueous solution A-2 is 3.56 times the amount of zirconium ions contained in the aqueous solution B-2.
The ratio of the amount of metal ions in this example is determined to be La: 8, Sr: 2, Mn: 10, and the oxide finally obtained, that is, lanthanum strontium manganate (LSM) The mass ratio of yttrium ion solid solution zirconia (YSSZ) is determined to be LSM: YSSZ = 0.50: 0.50.

Next, while maintaining the pH at 8 by simultaneously adding ammonia water to the aqueous ammonium hydrogen carbonate solution A-2, adding and mixing the zirconium ion aqueous solution B-2, the aqueous solution D- containing basic zirconium carbonate complex 2 was prepared.
Here, since precipitation did not generate | occur | produce in aqueous solution D-2, it confirmed that the basic zirconium carbonate complex was formed.

Next, a precipitate E-2 was prepared by adding and mixing the aqueous solution C-2 while maintaining the pH at 8 by simultaneously adding aqueous ammonia to the basic zirconium carbonate complex-containing aqueous solution D-2. .
Next, the resulting precipitate E-2 was washed with water several times with a suction filtration washing device to remove impurity ions, and then the solvent was replaced with ethanol, followed by drying at 80 ° C. for 24 hours in a dryer. To obtain a dried product F-2.
Next, the obtained dried product F-2 was pulverized in a mortar and heat-treated at 800 ° C. or 1000 ° C. in an electric furnace, and lanthanum strontium manganate (LSM) -yttrium ion solid solution zirconia (YSSZ) of Example 2 The composite ceramic powder G-2 was obtained. Here, LSM corresponds to A _1-x B _x C _1-y D _y O ₃ in the present invention.

  Next, 1.5 g of commercially available NiO powder is mixed with 0.5 g of polyethylene glycol (molecular weight: 400) and 10 g of ethanol in a ball mill, and then this mixed solution is heated to 80 ° C. to evaporate and remove ethanol. NiO paste was prepared. This NiO paste was applied by screen printing onto the surface of an 8 mol% yttria stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, which is a solid electrolyte, and then baked at 1300 ° C. for 2 hours, and a fuel electrode was formed on the 8YSZ substrate. I-2 was formed.

Next, 1.5 g of the composite ceramic powder G-2 (G-2B) obtained by heat-treating the dried product F-2 at 1000 ° C. for 6 hours was taken and ball milled together with 0.5 g of polyethylene glycol (molecular weight: 400) and 10 g of ethanol. Then, the mixed solution was heated to 80 ° C. to evaporate and remove ethanol to prepare LSM-YSSZ paste J-2.
The paste J-2 was applied by screen printing on the back surface of the 8YSZ substrate on which the fuel electrode I-2 was formed, and then fired at 1200 ° C. for 2 hours, and the composite ceramic powder of Example 2 was applied on the 8YSZ substrate. An air electrode K-2 made of a body was formed. Further, a platinum wire was wound around the side surface of the 8YSZ substrate to form a reference electrode, and the solid oxide fuel cell of Example 2 was formed.

"Example 3"
At the time of preparing the aqueous ammonium hydrogen carbonate solution A-3, ammonia water is added to adjust the pH to 9, the pH at the time of preparing the basic zirconium carbonate complex-containing aqueous solution D-3 is set to 9, and the reaction at the time of preparing the precipitate E-3 The composite ceramic powder of the dried product F-3 of Example 3 and lanthanum strontium manganate (LSM) -yttrium ion solid solution zirconia (YSSZ), except that the pH of the solution was set to 9. G-3 was obtained.

Next, a fuel electrode I-3 was formed on the surface of an 8 mol% yttria stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, which is a solid electrolyte, in the same manner as in Example 2.
Next, using a composite ceramic powder G-3 (G-3B) obtained by heat-treating the dried product F-3 at 1000 ° C. for 6 hours, an 8YSZ substrate on which the fuel electrode I-3 was formed in the same manner as in Example 2. An air electrode K-3 made of the composite ceramic powder of Example 2 was formed on the back surface of the substrate. Further, a platinum wire was wound around the side surface of the 8YSZ substrate to form a reference electrode, and the solid oxide fuel cell of Example 3 was formed.

"Comparative Example 1"
Sodium hydroxide (NaOH, manufactured by Kanto Chemical Co., Inc.) was dissolved in pure water to prepare a basic aqueous solution A-4 having a pH of 10.
Next, 9.21 g of chlorinated zirconium oxide octahydrate was dissolved in 250 g of pure water to prepare a zirconium ion aqueous solution B-4.
Next, 30.81 g of nickel nitrate hexahydrate and 2.09 g of yttrium nitrate hexahydrate are dissolved in 450 g of pure water, and an aqueous solution C-4 containing nickel ions and yttrium ions as metal E ions is obtained. Prepared.
The mass ratio of the oxide finally obtained by this comparative example, that is, nickel oxide (NiO) and yttrium ion solid solution zirconia (YSSZ) is NiO: YSSZ = 0.65: 0.35. It has been established.

Next, the aqueous solution B-4 and the aqueous solution C-4 were mixed, and then added to the aqueous solution A-4 and mixed to prepare a precipitate E-4. Here, the aqueous solution B-4 and the aqueous solution C-4 are mixed in advance when the aqueous solution A-4 and the aqueous solution B-4 are mixed first or when the aqueous solution A-4 and the aqueous solution C-4 are mixed. This is because precipitation occurs when A-4 and B-4 are mixed or when A-4 and C-4 are mixed.
Subsequently, the obtained precipitate E-4 was washed with water several times with a suction filtration washing device to remove impurity ions, and then the solvent was replaced with ethanol, followed by drying at 80 ° C. for 24 hours in a dryer. To obtain a dried product F-4.
Subsequently, the obtained dried product F-4 was pulverized in a mortar and heat-treated at 800 ° C. or 1000 ° C. in an electric furnace, and the composite of nickel oxide (NiO) -yttrium ion solid solution zirconia (YSSZ) of Comparative Example 1 was used. Ceramic powder G-4 was obtained.

Next, using a composite ceramic powder G-4 (G-4B) obtained by heat-treating the dried product F-4 at 1000 ° C. for 6 hours, 8 mol% having a thickness of 300 μm, which is a solid electrolyte, in the same manner as in Example 1. A fuel electrode I-4 made of the composite ceramic powder of Comparative Example 1 was formed on the surface of a yttria-stabilized zirconia (8YSZ) substrate.
Next, an air electrode K-4 was formed on the back surface of the 8YSZ substrate on which the fuel electrode I-4 was formed by the same method as in Example 1. Further, a platinum wire was wound around the side surface of the 8YSZ substrate to serve as a reference electrode, and the solid oxide fuel cell of Comparative Example 1 was formed.

"Comparative Example 2"
Aqueous ammonium hydrogen carbonate solution A-5 was prepared by dissolving 9.75 g of ammonium hydrogen carbonate in pure water and further adding aqueous ammonia to adjust the pH to 8 and making the total amount of the aqueous solution 241.75 g.
Next, 7.48 g of lanthanum nitrate hexahydrate, 0.92 g of strontium nitrate and 6.32 g of manganese nitrate hexahydrate are dissolved in 420 g of dilute nitric acid having a pH of 2.0, and A _1-x B _x C _1- the aqueous solution C-5 containing lanthanum ions and strontium ions and manganese ions as _y D _y O ₃ forming ions was prepared.
In addition, the ratio of the amount of metal ions in this comparative example is determined to be La: 8, Sr: 2, Mn: 10.

Next, the aqueous solution C-5 containing lanthanum ions, strontium ions, and manganese ions is added to and mixed with the aqueous ammonium bicarbonate solution A-5 while maintaining the pH at 8 by simultaneously adding aqueous ammonia. A precipitate L-5 was prepared.
Subsequently, the obtained precipitate L-5 was washed with water several times with a suction filtration washing device to remove impurity ions, and then the solvent was replaced with ethanol, followed by drying at 80 ° C. for 24 hours in a dryer. To obtain a dried product M-5. Subsequently, the obtained dried product M-5 was pulverized in a mortar and heat-treated in an electric furnace at 800 ° C. for 6 hours to obtain lanthanum strontium manganate (La _0.8 Sr _0.2 MnO ₃ , LSM) powder. N-5 was obtained.

Next, 0.75 g of the obtained LSM powder N-5 and 0.75 g of 10 mol% yttria-stabilized zirconia (10YSZ) (manufactured by Tosoh Corporation), 0.5 g of polyethylene glycol (molecular weight: 400) and 10 g of ethanol Then, the mixed solution was heated to 80 ° C. to evaporate and remove ethanol to prepare lanthanum strontium manganate (LSM) -yttria stabilized zirconia (10YSZ) paste J-5. .
That is, the mass ratio of lanthanum strontium manganate (LSM) to yttria stabilized zirconia (10YSZ) is LSM: 10YSZ = 0.50: 0.50.

Next, a fuel electrode I-5 was formed on the surface of an 8 mol% yttria stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, which is a solid electrolyte, in the same manner as in Example 2.
Next, using paste J-5, an air electrode K-5 made of the composite ceramic powder of Comparative Example 2 was formed on the back surface of the 8YSZ substrate on which the fuel electrode I-5 was formed in the same manner as in Example 2. . Further, a platinum wire was wound around the side surface of the 8YSZ substrate to form a reference electrode, and the solid oxide fuel cell of Example 2 was formed.

“Comparative Example 3”
Aqueous ammonium hydrogen carbonate A-6 was prepared by dissolving 9.75 g of ammonium hydrogen carbonate in pure water and further adding aqueous ammonia to adjust the pH to 8 and the total amount of the aqueous solution was 241.75 g.
Next, 420 g of pure water was mixed with 11.13 g of zirconium chloride octahydrate, 2.09 g of yttrium nitrate hexahydrate, 7.48 g of lanthanum nitrate hexahydrate, 0.92 g of strontium nitrate and manganese nitrate hexahydrate. 6.32 g of the product is dissolved, and zirconium ions, yttrium ions as metal E ions, lanthanum ions, strontium ions, and manganese ions as ions for forming A _1-x B _x C _1-y D _y O ₃ An aqueous solution B-6 containing was prepared.
Note that the amount of carbonate ions contained in the aqueous solution A-6 is 3.56 times the amount of zirconium ions contained in the aqueous solution B-6.
The ratio of the amount of metal ions in this example is determined to be La: 8, Sr: 2, Mn: 10, and the oxide finally obtained, that is, lanthanum strontium manganate (LSM) The mass ratio of yttrium ion solid solution zirconia (YSSZ) is determined to be LSM: YSSZ = 0.50: 0.50.

Next, the aqueous solution A-6 was mixed with the aqueous solution B-6 while maintaining the pH at 8 by simultaneously adding aqueous ammonia to the aqueous solution A-6 to prepare a precipitate E-6.
Next, the obtained precipitate E-6 was washed with water several times with a suction filtration washing device to remove impurity ions, and then the solvent was replaced with ethanol, followed by drying at 80 ° C. for 24 hours in a dryer. To obtain a dry product F-6.
Subsequently, the obtained dried product F-6 was pulverized in a mortar and heat-treated at 800 ° C. or 1000 ° C. in an electric furnace, and lanthanum strontium manganate (LSM) -yttrium ion solid solution zirconia (YSSZ) of Example 2 Composite ceramic powder G-6 was obtained.

  Next, a fuel electrode I-6 was formed in the same manner as in Example 2 on the surface of an 8 mol% yttria-stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, which is a solid electrolyte.

Next, 1.5 g of the composite ceramic powder G-6 (G-6B) obtained by heat-treating the dried product F-6 at 1000 ° C. for 6 hours was taken and ball milled together with 0.5 g of polyethylene glycol (molecular weight: 400) and 10 g of ethanol. Then, the mixed solution was heated to 80 ° C. to evaporate and remove ethanol to prepare LSM-YSSZ paste J-6.
This LSM-YSSZ paste J-6 was applied by screen printing on the back surface of the 8YSZ substrate on which the fuel electrode I-6 was formed, then baked at 1200 ° C. for 2 hours, and the comparative example 3 was applied on the 8YSZ substrate. An air electrode K-6 made of composite ceramic powder was formed. Further, a platinum wire was wound around the side surface of the 8YSZ substrate to form a reference electrode, and the solid oxide fuel cell of Example 2 was formed.

[Evaluation of composite ceramic powder]
Powder samples prepared in Examples 1 to 3 and Comparative Examples 1 and 3 were measured by powder X-ray diffractometry using a powder X-ray diffractometer (XRD, JDX3530M manufactured by JEOL (JEOL)). The crystallite diameter was calculated from the half width of the obtained diffraction peak. Moreover, about the composite ceramic powder of Example 1, it observed using the transmission electron microscope (TEM, JEM-2010 made from JEOL).
In Comparative Example 2, LSM powder N-5 was prepared alone and then mixed with 10YSZ powder, and no composite powder was formed. Therefore, it is meaningful for component identification by powder X-ray diffraction. In addition, since the degree of complexation cannot be evaluated even if the crystallite diameter is calculated, evaluation by powder X-ray diffraction measurement is not performed.

FIG. 2 is an XRD pattern of composite ceramic powder G-1 (G-1A) obtained by heat-treating the dried product F-1 of Example 1 at 800 ° C. for 6 hours. In the XRD pattern after the heat treatment, peaks attributed to YSSZ and NiO appear, and no peaks derived from other compounds are seen, indicating that the composite ceramic powder contains only these substances. The crystallite size of YSSZ was about 11 nm, and the crystallite size of NiO was about 19 nm.
Since YSSZ was substantially the same as yttria-stabilized zirconia (YSZ), the assignment of the YSSZ peak in XRD was performed with respect to the value of YSZ.
In addition, the XRD pattern of the composite ceramic powder G-1B of Example 1 heat-treated at 1000 ° C. for 6 hours also shows only peaks attributable to YSSZ and NiO, and the composite ceramic powder contains only these substances. It was found that it contained. The crystallite diameter could not be calculated due to the small half width.

FIG. 3 is a transmission electron microscope image of the composite ceramic powder G-1A. It can be seen that there are particles having a uniform particle size distribution of about 10 nm in the composite ceramic powder.
From the above results, it was found that the composite ceramic powder of Example 1 was composed of very fine YSSZ and NiO.

FIG. 4 is an XRD pattern of composite ceramic powder G-2 (G-2A) obtained by heat-treating the dried product F-2 of Example 2 at 800 ° C. for 6 hours. In the XRD pattern after the heat treatment, peaks attributed to YSSZ and LSM appear, and no peaks derived from other compounds are seen, indicating that the composite ceramic powder contains only these substances. The crystallite size of YSSZ was about 3 nm, and the crystallite size of LSM was about 14 nm. It was found that YSSZ was composed of fine LSM and YSSZ.
Similarly to Example 1, in the YSSZ of this example, the attribution of the peak in XRD is performed with respect to the value of YSZ.

FIG. 5 is a powder X diffraction (XRD) pattern of the composite ceramic powder G-3 (G-3A) obtained by heat-treating the dried product F-3 of Example 3 at 800 ° C. for 6 hours. Also in this example, peaks attributed to YSSZ and LSM appear in the XRD pattern after heat treatment, no peaks derived from other compounds are seen, and the composite ceramic powder contains only these substances. I understand that. The crystallite size of YSSZ was about 5 nm, and the crystallite size of LSM was about 13 nm, and it was found that it was composed of fine LSM and YSSZ.
Similarly to Example 1, in the YSSZ of this example, the attribution of the peak in XRD is performed with respect to the value of YSZ.

  With respect to these examples, the composite ceramic powder G-4 (G-4A) obtained by heat-treating the dried product F-4 of Comparative Example 1 at 800 ° C. for 6 hours was identified by XRD. As a result, it belongs to YSSZ and NiO. The peak derived from other compounds was not seen, and it was found that the composite ceramic powder contained only YSSZ and NiO, as in Example 1. On the other hand, the crystallite size of YSSZ was about 35 nm, and the crystallite size of NiO was about 51 nm, which was 2.5 times or more that of Example 1.

  Moreover, as a result of identifying the composite ceramic powder G-6 (G-6A) obtained by heat-treating the dried product F-6 of Comparative Example 3 at 800 ° C. for 6 hours by XRD, peaks attributed to YSSZ and LSM appeared. No peaks derived from other compounds were observed, and it was found that the composite ceramic powder contained only YSSZ and LSM, as in Example 2. The crystallite size of YSSZ was about 9 nm, the crystallite size of LSM was about 20 nm, and it was composed of fine LSM and YSSZ, but the crystallite size was larger than those of Examples 2 and 3.

[Characteristic evaluation of solid oxide fuel cell electrode]
The electrode reaction resistance of the fuel electrode or air electrode in the solid oxide fuel cells of Examples 1 to 3 and Comparative Examples 1 to 3 was measured using the electrochemical property evaluation apparatus shown in FIG. Here, dry air was supplied to the air electrode and the reference electrode, and humidified hydrogen gas having a composition of 3% H ₂ O-97% H ₂ was supplied to the fuel electrode at a flow rate of 50 mL / min.
In Examples and Comparative Examples in which the fuel electrode was formed using the prepared composite ceramic powder in the measurement, the fuel electrode was prepared by measuring the AC impedance between the reference electrode and the fuel electrode using the air electrode as a counter electrode. The electrode reaction resistance was evaluated.
Similarly, for the examples and comparative examples in which the air electrode was formed using the prepared composite ceramic powder, the air electrode was prepared by measuring the AC impedance between the reference electrode and the air electrode using the fuel electrode as a counter electrode. The electrode reaction resistance was evaluated.
The measurement temperature was 600 ° C. and 800 ° C., and the measurement frequency was 10 kHz to 0.1 Hz.

Electrode reaction resistance of the fuel electrode in solid oxide fuel cell of Example 1 is 0.058Ω / cm ² at 1.95Ω ^/ cm 2, 800 ℃ at 600 ° C., sufficiently low resistance value as a fuel electrode It was found that
Next, the electrode reaction resistance value of the air electrode in the solid oxide fuel cell of Example 2 was 0.42Ω / cm ² at 12.53Ω ^/ cm 2, 800 ℃ at 600 ° C..
Further, the electrode reaction resistance of the air electrode in the solid oxide fuel cell of Example 3, was 0.28Ω / cm ² at 8.58Ω ^/ cm 2, 800 ℃ at 600 ° C., both Examples 2 and 3 It was found that the air electrode exhibited a sufficiently low resistance value.

For these examples, the electrode reaction resistance of the fuel electrode in solid oxide fuel cell of Comparative Example 1 is 0.64Ω / cm ² at 13.22Ω ^/ cm 2, 800 ℃ at 600 ° C., Compared with the fuel electrode of Example 1, the resistance value increased significantly.
Next, the electrode reaction resistance value of the air electrode in the solid oxide fuel cell of Comparative Example 2 is 1.68Ω / cm ² at 24.57Ω ^/ cm 2, 800 ℃ at 600 ° C., Example 2 and 3 The resistance value increased compared to the air electrode.
The electrode reaction resistance value of the air electrode in the solid oxide fuel cell of Comparative Example 3 is 0.59Ω / cm ² at 15.41Ω ^/ cm 2, 800 ℃ at 600 ° C., the resistance value of Comparative Example Although it was lower than 2, it increased compared to the air electrodes of Examples 2 and 3.

  Summarizing the above results, Table 1 shows the raw material composition ratios and production conditions of the composite ceramic powders of Examples 1 to 3 and Comparative Examples 1 to 3 and each electrode, and the evaluation values and electrode measurement results of the produced composite ceramic powders. It shows in Table 2.

From the results of the evaluation, the crystallite diameter of each component in the composite ceramic particles obtained in Examples 1 to 3 is smaller than the crystallite diameter of each component in the corresponding comparative example, compared to the comparative example. It was found that composite ceramic particles that were homogeneous and excellent in distribution were obtained.
Moreover, the reaction resistance value of each electrode formed in Examples 1 to 3 is lower than the reaction resistance value of each electrode formed in the corresponding Comparative Examples 1 to 3, and exhibits better electrode characteristics than the comparative example. I understood. This is due to the fact that the crystallite size contained in the composite ceramic powder prepared in the example is smaller than that prepared in the comparative example and that the composition of the composite ceramic powder prepared in the example is homogeneous. This is probably because the electrode in the example is an electrode having many three-phase interfaces and a uniform composition at the electrode interfaces.

From the above results, the composite ceramic powder of the present embodiment is excellent in distribution and composition controllability, and the electrodes used in the solid oxide fuel cell of the present embodiment have many three-phase interfaces. It was confirmed that the air electrode was excellent in oxygen reduction ability and electronic conductivity, and that the fuel electrode was excellent in hydrogen oxidation ability and electronic conductivity.
Thus, the usefulness of the present invention was confirmed.

According to the method for manufacturing a composite ceramic powder of the present invention, that the oxide or nickel oxide expressed by at least _{A 1-x B x C 1} -y D y O 3, the ions of the metal E is dissolved And a zirconia to which oxygen ion conductivity is imparted. A method for producing a composite ceramic powder comprising first reacting zirconium ions and carbonate ions in a basic aqueous solution, One selected from the group of A, B, C and D to form a zirconium carbonate complex and then constitute the oxide represented by A _1-x B _x C _1-y D _y O ₃ Alternatively, by adding two or more kinds of metal ions or nickel ions and metal E ions into the basic aqueous solution in which the basic zirconium carbonate complex is formed, the groups A, B, C and D are added. Select from A precipitate containing a complex salt consisting of one or more metal ions, the metal E ion, and the basic zirconium carbonate complex, or the nickel ion and the metal E ion, Since a precipitate containing a complex salt composed of the basic zirconium carbonate complex is generated, and then this precipitate is heat-treated at a temperature of 200 ° C. or higher, at the nanometer level in a plurality of types of oxide particles. In addition to its excellent distribution and composition controllability, it has many three-phase interfaces when applied to a solid oxide fuel cell, and it has a combination of oxygen reduction ability and electron conductivity, or hydrogen oxidation ability and electron conductivity. Ceramic powder can be obtained easily and inexpensively.

  According to the composite ceramic powder of the present invention, since it is obtained by the method for producing a composite ceramic powder of the present invention, it is excellent in distribution and composition controllability at the nanometer level in a plurality of types of oxide particles, and solid oxidation. When applied to a physical fuel cell, it is possible to provide a composite ceramic powder capable of forming an electrode excellent in oxygen reduction ability and electron conductivity, or hydrogen oxidation ability and electron conductivity.

According to the solid oxide fuel cell of the present invention, since the composite ceramic powder obtained by the method for producing a composite ceramic powder of the present invention is used as an electrode material, oxygen reduction ability and electron conductivity, or hydrogen oxidation ability As a result, the output and characteristics of the battery can be improved.
Therefore, according to the present invention, a composite ceramic powder that can be suitably used as an electrode of a solid oxide fuel cell can be easily obtained, and a solid oxide fuel cell using the composite ceramic powder can be obtained. Since the characteristics can be improved, the utility value is great in various industrial fields including solid oxide fuel cells.

DESCRIPTION OF SYMBOLS 1 Electrolyte 2 Reference electrode 3 Air electrode 4 Fuel electrode 5 Platinum net 6 Glass seal 7, 8 Alumina tube 9 Platinum wire 10 Dry air 11 Humidified hydrogen gas

Claims (6)

At least A _1-x B _x C _1-y D _y O ₃ (wherein A is one or two elements selected from the group of La and Sm, B is selected from the group of Sr, Ca and Ba) One or more elements, C is one or more elements selected from the group of Co, Ga and Mn, D is one or two elements selected from the group of Fe, Mg and Ni Oxygen ion conductivity in zirconium oxide by solid solution in the oxide or nickel oxide represented by 0.1 ≦ x ≦ 0.5, 0 ≦ y ≦ 1.0) and zirconium oxide. Zirconia in which ions of metal E capable of imparting properties are dissolved and oxygen ion conductivity is imparted, and a method for producing a composite ceramic powder comprising:
A first step of reacting zirconium ions and carbonate ions in a basic aqueous solution to form a basic zirconium carbonate complex;
One or two or more kinds of metal ions selected from the group consisting of A, B, C and D to constitute the oxide represented by A _1-x B _x C _1-y D _y O ₃ One or two selected from the group of A, B, C, and D by adding nickel ions and metal E ions to the basic aqueous solution in which the basic zirconium carbonate complex is formed. A first precipitate containing a complex salt comprising ions of at least a metal, the metal E ion, and the basic zirconium carbonate complex, or the nickel ion, the metal E ion, and the base A second step of generating a second precipitate containing a complex salt comprising a functional zirconium carbonate complex;
And a third step of heat-treating the first or second precipitate at a temperature of 200 ° C. or higher. It contains at least an oxide represented by A _1-x B _x C _1-y D _y O ₃ and zirconia to which oxygen ion conductivity is imparted by dissolving a metal E ion. A method for producing a composite ceramic powder comprising:
In the first step, the zirconium ion and carbonate ion are reacted in a basic aqueous solution containing the carbonate ion amount that is 3.2 times or more and 5.3 times or less the zirconium ion amount, and Forming a basic zirconium carbonate complex;
The method for producing a composite ceramic powder according to claim 1, wherein in the third step, the first precipitate generated in the second step is heat-treated at a temperature of 200 ° C or higher. . A method for producing a composite ceramic powder comprising nickel oxide and zirconia to which oxygen ion conductivity is imparted by dissolving ions of metal E,
In the first step, the zirconium ion and carbonate ion are reacted in a basic aqueous solution containing the carbonate ion amount that is 0.5 to 5.3 times the zirconium ion amount, and Forming a basic zirconium carbonate complex;
The method for producing a composite ceramic powder according to claim 1, wherein in the third step, the second precipitate produced in the second step is heat-treated at a temperature of 200 ° C or higher. .   The method for producing a composite ceramic powder according to any one of claims 1 to 3, wherein the pH of the basic aqueous solution is 7 or more and 9 or less.   A composite ceramic powder obtained by the method for producing a composite ceramic powder according to any one of claims 1 to 4.   A solid oxide fuel cell comprising the composite ceramic powder according to claim 5 as an electrode material.