JP5516468B2 - Composite ceramic material, method for producing the same, and solid oxide fuel cell - Google Patents

Description

  The present invention relates to a composite ceramic material, a manufacturing method thereof, and a solid oxide fuel cell (SOFC), and more particularly, a composite having excellent distribution and composition controllability of zirconia particles and perovskite oxide. The present invention relates to a ceramic material, a manufacturing method thereof, and a solid oxide fuel cell capable of significantly improving the output characteristics of the battery by using the composite ceramic material as an electrode material.

A solid oxide fuel cell (SOFC) is a fuel electrode in which a fuel such as hydrogen or hydrocarbon reacts with oxide ions to extract electrons, and oxygen is reduced by the electrons generated at the fuel electrodes to produce oxide ions. It consists of an air electrode to be generated and a solid electrolyte having a role of transporting oxide ions generated at the air electrode to the fuel electrode.
In this SOFC, generally, the fuel electrode is composed of a composite of solid electrolyte particles and a substance that becomes a catalyst in the reaction of fuel and oxide ions, while the air electrode is composed of solid electrolyte particles and It is composed of a complex with a catalyst that reduces oxygen.

By the way, in this air electrode, the reaction field is said to be the interface (three-phase interface) where the three-phase of solid electrolyte particles and the catalyst constituting the air electrode and air or oxygen gas which is a gas phase are in contact. ing. For example, in SOFC using a composite material (LSM-YSZ) of lanthanum strontium manganite (LSM) as a fuel electrode and yttria stabilized zirconia (YSZ) as an electrolyte, all of LSM, YSZ and air or oxygen gas The part that contacts is the three-phase interface. That is, by increasing the number of three-phase interfaces, an air electrode with high reaction efficiency can be obtained.
In addition to the large number of three-phase interfaces, the electrolyte particles and catalyst particles are placed inside the electrode in order to spread electrons inside the electrode and to smoothly transport oxygen ions generated by the oxygen reduction reaction to the solid electrolyte. It is desirable to have a structure with continuous connections.

In view of this, there has been proposed an electrode manufacturing method in which a (network) skeleton three-dimensionally connected by a catalyst or electrolyte particles is formed, and the other material is combined around the skeleton to form a network of both.
For example, the production of a three-dimensional network electrode in which ceria, which is a solid electrolyte, is deposited around nickel oxide (which generates metal nickel as an electrode catalyst by reduction) by spray pyrolysis has been reported (Patent Document 1). .
Further, a method has been proposed in which a nickel oxide powder is immersed in a samarium salt or cerium salt solution, and the surface of nickel oxide is covered with samarium-doped ceria to form a network of this samarium-doped ceria (solid electrolyte phase) ( Patent Document 2).

Japanese Patent No. 4211254 JP 2006-228587 A

However, in the above-described methods, the raw material particles that are the skeleton of the network, or the raw material particles that are the skeleton of the network are relatively large from several hundred nanometers to several micrometers, and the particles that form the resulting network are Due to sintering and grain growth, it becomes coarser than several micrometers. As described above, since the interface of the electrode is a key factor for the reaction, it has been desired to form a skeleton at a finer level in order to obtain a more active electrode.
In these methods, the conductivity is improved by bonding ionic conductivity solid electrolytes present on the surface of each particle to each other. For this reason, nickel oxide as a catalyst is contained in the solid electrolyte. There was also a problem that a sufficient three-phase interface could not be obtained because of being embedded.

  The present invention has been made to solve the above-described problems, and is excellent in the distribution and composition controllability of a plurality of types of oxide particles, and has many three-phase interfaces and excellent oxygen ion generation. It is an object of the present invention to provide a composite ceramic material, a manufacturing method thereof, and a solid oxide fuel cell.

As a result of intensive investigations to solve the above problems, the present inventors have obtained a three-dimensional network skeleton structure by combining zirconia particles made of yttria-stabilized zirconia, and the surface of this network skeleton structure. A _1-x B _x C _1-y D _y O _3-δ (where A is one or more elements selected from the group of La, Sm and Fe, and B is Sr and Ni). One or two elements selected from the group, C is one or two elements selected from the group of Co and Mn, and D is one or two elements selected from the group of Fe and Ni (But different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ ≦ 1, and when 0 <δ, a constant oxygen defect is contained) if caused to combine the oxides, the a _1-x B _x C ₁ is zirconia and catalyst is a solid electrolyte _{y D} y O oxide represented by _3-[delta] is often three-phase interface by having a three-dimensional network structure in a fine scale, reticulated skeleton structure by high oxygen ion conductivity of zirconia throughout the electrode And has high electronic conductivity due to the network structure of the oxide represented by A _1-x B _x C _1-y D _y O _3-δ along the zirconia skeleton, and high from these characteristics The present inventors have found that a composite ceramic material serving as an air electrode exhibiting performance can be easily obtained, thereby completing the present invention.

That is, the composite ceramic material of the present invention has a three-dimensional network skeleton structure formed by binding zirconia particles made of yttria-stabilized zirconia, and A _1-x B _x C _{1- y} D _y O _3-δ (wherein A is one or more elements selected from the group of La, Sm and Fe, and B is one or two elements selected from the group of Sr and Ni) Element, C is one or two elements selected from the group of Co and Mn, D is one or two elements selected from the group of Fe and Ni (however, different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ ≦ 1, and a constant oxygen defect is contained when 0 <δ). Features.

The average particle size of the zirconia particles is preferably 10 nm or more and 400 nm or less.
The ratio (W _ABCD / W _YSZ ) of the mass (W _ABCD ) of the A _1-x B _x C _1-y D _y O _{3-δ to} the mass (W _YSZ ) of the zirconia particles is 5/95 or more and 95 / 5 or less is preferable.

The method for producing a composite ceramic material of the present invention includes a zirconia fine particle composed of yttria-stabilized zirconia and A _1-x B _x C _1-y D _y O _3-δ (where A is a group of La, Sm and Fe). One or more elements selected from: B is one or two elements selected from the group of Sr and Ni; C is one or two elements selected from the group of Co and Mn , D is one or two elements selected from the group of Fe and Ni (however, different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ ≦ 1 and 2 or more ions selected from the group of A, B, C and D among the elements contained in the oxide represented by the formula: By adjusting the hydrogen ion index of the zirconia fine particle dispersion containing benzene to 4 or more and less than 7 The zirconia fine particles are aggregated to form a three-dimensional network aggregate structure, and then the hydrogen ion index of the dispersion containing the network aggregate structure composed of the zirconia fine particles is adjusted to 7 or more, Precipitating the oxide represented by the A _1-x B _x C _1-y D _y O _3-δ by heat treatment on the surface of the network aggregate structure composed of zirconia fine particles, A zirconia fine particle aggregate structure in which the precursor produced by heat treatment of an oxide represented by A _1-x B _x C _1-y D _y O _3-δ is heated at a temperature of 800 ° C. or higher and 1300 ° C. or lower. heat treatment, the zirconia fine reticulated said the surface of the skeletal structure a _1-x B _x C of the zirconia fine three-dimensional zirconia particles obtained by sintering to form a coherent structure Oxide represented by _{-y D y} O _3-δ is and generates a composite ceramic material attached.

  The dispersion average particle diameter of the zirconia fine particles in the zirconia fine particle dispersion is preferably 0.1 nm or more and 30 nm or less.

  The solid oxide fuel cell of the present invention is characterized in that the composite ceramic material of the present invention is an air electrode material.

According to the composite ceramic material of the present invention, zirconia particles composed of yttria-stabilized zirconia are combined to form a three-dimensional network skeleton structure, and A _1-x B _x C _1-- is formed on the surface of the network skeleton structure. since was coupled oxide represented by _y D _y O _3-δ, the distribution of the oxide represented by zirconia particles and _{a 1-x B x C 1} -y D y O 3-δ it can be improved, thereby improving the composition control of oxide represented by the zirconia particles and _{a 1-x B x C 1} -y D y O 3-δ. Therefore, there are many three-phase interfaces, excellent ionic conductivity derived from the zirconia skeleton, and the oxide represented by A _1-x B _x C _1-y D _y O _3-δ formed along the zirconia skeleton. It is possible to provide a composite ceramic material having both high electronic conductivity and high performance when using the composite ceramic material of the present invention as an SOFC air electrode.

According to the method for producing a composite ceramic material of the present invention, zirconia fine particles composed of yttria-stabilized zirconia and A _1-x B _x C _1-y D _y O _3-δ (where A is La, Sm, and Fe) One or two or more elements selected from the group of B, B is one or two elements selected from the group of Sr and Ni, C is one or two elements selected from the group of Co and Mn And D is one or two elements selected from the group of Fe and Ni (however, different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ 1 or 2 or more selected from the group consisting of A, B, C, and D among the elements contained in the oxide represented by δ ≦ 1 and containing constant oxygen defects when 0 <δ The hydrogen ion index of the zirconia fine particle dispersion containing ions is adjusted to 4 or more and less than 7. By agglomerating the zirconia fine particles into a three-dimensional network aggregate structure, and then adjusting the hydrogen ion index of the dispersion containing the network aggregate structure composed of the zirconia fine particles to 7 or more, wherein _{a 1-x B x C 1} -y D y O 3-δ oxide was precipitated precursor caused by heat treatment, represented on the surface of the mesh-like aggregate structure consisting of the zirconia fine particles, then, The zirconia fine particle aggregate structure in which the precursor produced by heat treatment of the oxide represented by A _1-x B _x C _1-y D _y O _3-δ is heated to a temperature of 800 ° C. or higher and 1300 ° C. or lower. since it was decided to heat treatment Te, the the surface of the reticulated skeleton structure of a three-dimensional zirconia particles obtained zirconia fine particles forming a zirconia fine particle aggregate structure by sintering a The _{-x B x C 1-y D} y O 3-δ composite ceramic material oxide is bonded, represented by, it can be manufactured easily and inexpensively.

  According to the solid oxide fuel cell of the present invention, since the composite ceramic material of the present invention is used as the air electrode material of the solid oxide fuel cell, the ionization reaction between electrons and oxygen gas supplied from an external circuit is efficiently performed. Can be done well. Therefore, the amount of oxygen ionization can be increased, and the generated oxygen ions can be efficiently supplied to the electrolyte. As a result, the output characteristics of the battery can be greatly improved.

It is a schematic diagram which shows the electrochemical property evaluation apparatus for evaluating the air electrode of the solid oxide fuel cell of one Embodiment of this invention. It is a figure (lower part) which shows the TEM image (upper part) which shows the air electrode produced using the composite ceramic powder of Example 1 of this invention, and the element distribution obtained by EDX. It is a scanning electron microscope (SEM) image which shows the air electrode produced using the composite ceramic powder of Example 2 of this invention. 2 is a scanning electron microscope (SEM) image showing an air electrode produced using the material of Comparative Example 1. FIG. 6 is a scanning electron microscope (SEM) image showing an air electrode produced using the material of Comparative Example 2.

The composite ceramic material of the present invention, the manufacturing method thereof, and the form for carrying out the solid oxide fuel cell 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.

[Composite ceramic materials]
In the composite ceramic material of the present embodiment, zirconia particles composed of yttria-stabilized zirconia are combined to form a three-dimensional network skeleton structure, and A _1-x B _x C _1-y is formed on the surface of the network skeleton structure. D _y O _3-δ (wherein A is one or more elements selected from the group of La, Sm and Fe, and B is one or two elements selected from the group of Sr and Ni) , C is one or two elements selected from the group of Co and Mn, D is one or two elements selected from the group of Fe and Ni (however, different from A), 0 .. 2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ ≦ 1, and a constant oxygen defect is contained when 0 <δ)). .

  Here, the three-dimensional network skeleton structure is a structure in which a plurality of zirconia particles are combined to form a dendritic structure, which is stretched in three dimensions to form a network structure. The voids formed inside are stretched in three dimensions to form a network-like void, and in some cases, a part of the void remains in the network-like skeleton structure of the zirconia particles. Structure.

The average particle diameter of the zirconia particles in the composite ceramic material is preferably 10 nm or more and 400 nm or less, more preferably 10 nm or more and 300 nm or less.
Here, the reason why the average particle diameter of the zirconia particles is 10 nm or more and 400 nm or less is that when the average particle diameter is less than 10 nm, the temperature exceeding 800 ° C. is required to form the composite ceramic material as shown in the manufacturing method described later. This is because it is difficult to suppress the grain growth of zirconia particles to less than 10 nm due to the necessity of heat treatment in the case of, and on the other hand, when the average particle diameter exceeds 400 nm, the surface area becomes small and a three-dimensional network structure is formed. Since it becomes coarse, a sufficient three-phase interface cannot be obtained, which is not preferable.

The ratio (W _ABCD / W _YSZ ) of the mass (W _ABCD ) of A _1-x B _x C _1-y D _y O _{3-δ to} the mass of zirconia particles (W _YSZ ) in this composite ceramic material is 5/95. The ratio is preferably 95/5 or less, more preferably 10/90 or more and 90/10 or less.
Here, the ratio (W _ABCD / W _YSZ ) was set to 5/95 or more and 95/5 or less because when the ratio (W _ABCD / W _YSZ ) was less than 5/95, the electron conductivity and the oxygen ion reduction catalyst Since the amount of the catalyst in the electrode that bears the amount decreases, it is not preferable. On the other hand, when it exceeds 95/5, the amount of the zirconia particles that bear the ion conductivity becomes insufficient, which is not preferable.

[Method of manufacturing composite ceramic material]
The method for producing the composite ceramic material of the present embodiment includes a zirconia fine particle composed of yttria-stabilized zirconia, A _1-x B _x C _1-y D _y O _3-δ (where A represents La, Sm and Fe). One or more elements selected from the group, B is one or two elements selected from the group of Sr and Ni, C is one or two elements selected from the group of Co and Mn The element, D, is one or two elements selected from the group of Fe and Ni (however, different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ 1 or more ions selected from the group consisting of A, B, C, and D among the elements contained in the oxide represented by The hydrogen ion index of the zirconia fine particle dispersion containing By agglomerating the zirconia fine particles into a three-dimensional network aggregate structure, and then adjusting the hydrogen ion index of the dispersion containing the network aggregate structure composed of the zirconia fine particles to 7 or more, Precipitating the oxide represented by the A _1-x B _x C _1-y D _y O _3-δ by heat treatment on the surface of the network aggregate structure composed of zirconia fine particles, A zirconia fine particle aggregate structure in which the precursor produced by heat treatment of an oxide represented by A _1-x B _x C _1-y D _y O _3-δ is heated at a temperature of 800 ° C. or higher and 1300 ° C. or lower. The A _1-x B _x is formed on the surface of the network skeleton structure of three-dimensional zirconia particles obtained by heat treatment and sintering the zirconia fine particles forming the zirconia fine particle aggregate structure. This is a method for producing a composite ceramic material in which an oxide represented by C _1-y D _y O _3-δ is bonded.

Here, the “precursor produced by heat treatment of an oxide represented by A _1-x B _x C _1-y D _y O _3-δ ” means A _1-x B _x C _1-y D _y O Among the elements contained in the oxide represented by _3-δ , the pH of the solution containing one or more ions selected from the group of A, B, C, and D is 7 or more, A hydroxide or carbonate containing one or more elements selected from the group of A, B, C, and D precipitated from the solution, and is A _1-x B _x C by heat treatment. It is a substance that forms an oxide represented by _1-y D _y O _3-δ . In addition, the “precursor produced by heat treatment of the oxide represented by A _1-x B _x C _1-y D _y O _3-δ ” is referred to as “A _1-x B _x C _1-y D _It may be expressed as “ _y O _3-δ precursor”.

Next, the manufacturing method of this composite ceramic material will be described in detail.
"Preparation of zirconia fine particle dispersion"
And zirconia fine particles made of yttria-stabilized zirconia _{(YSZ), A 1-x} B x C 1-y D y O 3-δ ( wherein, A 1 or is selected La, from the group of Sm and Fe or 2 More than one element, B is one or two elements selected from the group of Sr and Ni, C is one or two elements selected from the group of Co and Mn, D is a group of Fe and Ni 1 or 2 elements selected from the above (but different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ ≦ 1, and 0 <δ 1 or 2 or more types of ions selected from the group of A, B, C and D among the elements contained in the oxide represented by (containing a constant oxygen defect) To obtain a zirconia fine particle dispersion.
The yttria-stabilized zirconia fine particles can be produced by a hydrothermal synthesis method or a firing method. For example, the following method is suitable (see Japanese Patent Application Laid-Open No. 2006-16236).

This method is a method of producing a metal oxide precursor by neutralizing a metal salt solution with a basic solution, and producing metal oxide nanoparticles from the metal oxide precursor. Where m is the valence of the metal ions or metal oxide ions, and n is the molar ratio of the hydroxyl groups in the basic solution, the m and n are represented by the following formula 0.5 <n <m (1)
In order to satisfy the above, a basic solution is added to the metal salt solution to partially neutralize the metal salt solution, then an inorganic salt is added to the partially neutralized solution to form a mixed solution, and the mixed solution is heated by a method of heating. is there.

  As this metal salt solution, an aqueous solution containing an yttrium (Y) salt and a zirconium (Zr) salt is preferably used.

One or more ions selected from the group of A, B, C, and D among the elements contained in the oxide represented by A _1-x B _x C _1-y D _y O _3-δ As a substance that generates A, B, C and D, an inorganic salt such as chloride, nitrate, sulfate, etc., an organic salt such as acetate, citrate, iodide, Halides such as bromide and fluoride can be mentioned.

  As the dispersion medium, water is preferable, and other alcohols such as methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol: IPA), butanol, pentanol, hexanol, octanol, diacetone alcohol, and ethyl acetate. , Butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, esters such as γ-butyrolactone, diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve) ), Ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether Ethers such as tellurium, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), ketones such as acetylacetone and cyclohexanone, amides such as dimethylformamide, N, N-dimethylacetoacetamide and N-methylpyrrolidone, ethylene glycol And glycols such as diethylene glycol and propylene glycol. These may be used alone or in combination of two or more.

  The concentration of zirconia fine particles comprising yttria-stabilized zirconia in this zirconia fine particle dispersion is not particularly limited, but when obtaining a composite ceramic material by pH control described later, from the viewpoint of productivity and handling properties, zirconia About 0.5 mass%-10 mass% of particle | grains are preferable.

The dispersion average particle diameter of zirconia fine particles comprising yttria-stabilized zirconia in this zirconia fine particle dispersion is preferably 0.1 nm or more and 30 nm or less, more preferably 0.1 nm or more and 20 nm or less.
Here, the reason why the dispersion average particle diameter of the zirconia fine particles is 0.1 nm or more and 30 nm or less is that when the dispersion average particle diameter is less than 0.1 nm, the zirconia fine particles exhibit properties as a colloid in the dispersion described later. On the other hand, if it exceeds 30 nm, the specific surface area of the three-dimensional network aggregate structure formed by the zirconia fine particles is not sufficient, and A _1-x B _x C _1-y D _y O by subsequent pH adjustment _{When the} precursors generated by heat treatment of the oxide represented by _3-δ are deposited, these precursors are deposited on the surface other than the surface of the three-dimensional network aggregate structure of zirconia fine particles, and as a result, the distribution of the composition This is because a composite ceramic material having a poor composition and a non-uniform composition may be produced.

Here, the dispersion average particle diameter is an optical measurement of the speed at which particles in the dispersion diffuse due to Brownian motion by the dynamic light scattering method, and the horizontal axis represents the dispersion particle diameter of the particles in the dispersion. The particle size distribution chart is obtained by taking the number of particles having the dispersed particle diameter on the vertical axis, and the dispersed particle diameter is the largest in the figure.
Moreover, the pH of this dispersion liquid needs to be less than 4, and it is more preferable if it is 2.5 or less. The pH of the dispersion is less than 4 because when the pH is 4 or more, the zirconia fine particles are aggregated and it is difficult to obtain a good dispersion state. This is because it becomes difficult to obtain an aggregated structure of zirconia fine particles having a network structure, which may make it impossible to obtain a composite ceramic material having good characteristics or an air electrode for SOFC.

“Preparation of Ceramics A _1-x B _x C _1-y D _y O _3-δ Precursor Composite”
Next, this zirconia fine particle dispersion is mixed with an alkali such as aqueous ammonia, ammonium carbonate, ammonium hydrogen carbonate, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate and other inorganic alkali, methyl Alkylamines such as amine, ethylamine and propylamine, alcohol amines such as methanolamine and ethanolamine, etc. are added to adjust the pH of this dispersion to 4 or more and less than 7.

  Here, the pH was adjusted to 4 or more and less than 7 because only the zirconia fine particles were first aggregated to form a three-dimensional network structure and selected from the group of A, B, C, and D 1 type or 2 types of ions to be added are ammonia water, ammonium carbonate, ammonium hydrogen carbonate, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate and other inorganic salts, methylamine, This is to prevent precipitation by reacting with an alkali such as an alkylamine such as ethylamine or propylamine, or an alcoholamine such as methanolamine or ethanolamine.

About each temperature of said zirconia fine particle dispersion and alkali, normal temperature may be sufficient, More preferably, it is the range of 1 degreeC-50 degreeC.
As a result, a dispersion in which a three-dimensional network structure in which only zirconia fine particles are aggregated and one or more ions selected from the group of A, B, C, and D coexist can be obtained. It becomes.

  Next, this zirconia fine particle network aggregate structure and a dispersion containing one or more ions selected from the group of A, B, C and D are mixed with an alkali such as ammonia water, ammonium carbonate, carbonic acid. Inorganic salts such as ammonium hydrogen, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide, potassium carbonate and potassium hydrogen carbonate, alkylamines such as methylamine, ethylamine and propylamine, alcohol amines such as methanolamine and ethanolamine , Etc. are added to adjust the pH of the dispersion containing the zirconia fine particle network aggregate structure and one or more ions selected from the group of A, B, C and D to 7 or more. .

Here, the pH of the dispersion was adjusted to 7 or more because one or more elements selected from the group of A, B, C, and D in the dispersion were added to hydroxide or It precipitates such as carbonates _{(a 1-x B x C} 1-y D y O precursor resulting from oxide to a heat treatment represented by _3-[delta]) as well on the surface of the zirconia fine net-like aggregate structure It is for making it precipitate.
About the temperature of each of the solution and the alkali containing the zirconia fine particle network aggregate structure and one or more ions selected from the group of A, B, C and D, normal temperature may be used. Preferably it is the range of 1 to 50 degreeC.
_{Thus, A 1-x B x C} 1-y D y O 3-δ _Ceramic precursor is precipitated A _1-x B _{x C} 1 on the surface of the three-dimensional net-like aggregate structure zirconia fine particles are aggregated _-y D _y O _3-δ precursor composite is to be produced.

"Preparation of Zirconia _{-A 1-x B x C 1} -y D y O 3-δ complex ceramic powder"
Using conventional filtration and washing apparatus or the like, the above-mentioned ceramic _{· A 1-x B x C} 1-y D y O 3-δ ceramics _· A _1-x from the dispersion containing the precursor composite B _{x C 1-} separating the _y D _y O _3-δ precursor composite, alkali ions such as the ceramics _{· a 1-x B x C} 1-y D y O 3-δ precursor complex was washed with pure water The impurity ions are removed and then dried using a dryer. Drying temperature is preferably lower than 200 ° C., this ceramics _· A _{1-x B} at 200 ° C. or higher _{x C 1-y D y O} 3-δ A 1-x precursor composite in B _{x C 1-y} Since the D _y O _3-δ precursor changes to an oxide represented by A _1-x B _x C _1-y D _y O _3-δ , an error occurs when measuring the amount of dry matter. It is for, when performing formation and drying simultaneously _{a 1-x B x C 1} -y D y O oxide represented by _3-[delta] is not particularly limited.
Here resulting dried product, the surface _{A 1-x B x C 1} -y D y O of the aggregate structure zirconia fine particles of nanometer size fine yttria-stabilized zirconia are aggregated in a three-dimensional reticulated _In this state, the _3-δ precursor is precipitated.

  Next, the obtained dried product is, for example, 800 ° C. or higher and 1300 ° C. or lower, more preferably 800 ° C. or higher and 1250 ° C. or lower, more preferably 1000 ° C. or higher and 1200 ° C. or lower in an air atmosphere using an electric furnace or the like. By performing heat treatment at the following temperature, zirconia fine particles made of fine yttria-stabilized zirconia having a nanometer size, which form an aggregate structure aggregated in a three-dimensional network, are sintered together. By this operation, the zirconia fine particles are bonded to each other, thereby joining the interface between the zirconia particles to form an ion conductive path, and a three-dimensional network skeleton structure having continuous ionic conductivity in the structure. Get.

By this heat treatment, the zirconia fine particles grow into zirconia particles having a diameter of about 10 nm to 400 nm, and the zirconia particles having such a particle diameter form a three-dimensional network skeleton structure. The A _1-x B _x C _1-y D _y O _3-δ precursor is oxidized to an oxide represented by A _1-x B _x C _1-y D _y O _3-δ , Even when the zirconia particles are grown, they are not taken into the skeleton structure of the zirconia particles and exist on the surface thereof. In this manner, an oxide represented by A _1-x B _x C _1-y D _y O _3-δ is bonded to the surface of the three-dimensional network skeleton structure in which zirconia particles composed of yttria-stabilized zirconia are bonded. Thus, the composite ceramic material of this embodiment can be produced.

Here, the reason for limiting the heat treatment temperature and 800 ° C. or higher and 1300 ° C. or less, the heat treatment temperature is lower than 800 ° C., poor bonding between the zirconia particles, with no sufficient ionic conductivity is obtained, A _1- generation of _{x B x C 1-y D} y O 3-δ a 1-x B x C 1-y D y O oxide represented by _3-[delta] from the precursor is because insufficient, On the other hand, if the temperature exceeds 1300 ° C., the grain growth of zirconia proceeds excessively, and the average particle diameter of the zirconia particles cannot be kept below 400 nm. As a result, the resulting composite ceramic material, particularly a solid oxide fuel cell This is because the specific surface area of the working air electrode is not sufficient.
This heat treatment may be performed at a time or may be performed in a plurality of times.

"Molding of composite ceramic materials"
Here, a method for forming the composite ceramic material will be described.
The ceramic material is usually formed in a powder state and then sintered to obtain the ceramic material. The powder in the composite ceramic material of the present embodiment, there is a dried product of the above ceramic _{· A 1-x B x C} 1-y D y O 3-δ precursor composite _{but, A 1-x B} x The C _1-y D _y O _3-δ precursor is a hydroxide, carbonate or the like and is not stable, and is oxidized by A _1-x B _x C _1-y D _y O _3-δ during heating. Since a large volume change or gas generation may occur when changing to an object, it is not preferable from the viewpoint of handling. Therefore, heat treatment is performed at about 800 ° C. in advance, and A _1-x B _x C _1-y D _y O ₃₋ It is preferable that the _δ precursor is an oxide represented by A _1-x B _x C _1-y D _y O _3-δ .

Therefore, a manufacturing process of the composite ceramic material in two stages, the first stage generates the oxide represented by _{A 1-x B x C 1} -y D y O 3-δ, and zirconia particles An oxide represented by A _1-x B _x C _1-y D _y O _3-δ was bonded to the surface by heat treatment at a temperature and a time not to form a three-dimensional network skeleton structure. particle diameter of zirconia particles of the order of 100nm from several 10nm is bound weakly, zirconia _{-A 1-x B x C 1} -y D y O 3-δ thereby form a composite ceramic powder. As the heat treatment temperature in the first stage, for example, the upper limit value may be about 800 ° C. to 1000 ° C.

The composite ceramic powder thus obtained is molded into a required shape to obtain a molded product. The molding method is not particularly limited as long as it is a normal ceramic molding method. In addition to extrusion molding and pressure pressing, a binder component (for example, polyethylene glycol, polyvinyl butyral, etc.) other than water and an organic solvent is added to the composite ceramic powder. It can be added to form a slurry or paste, which can be formed by a method such as tape forming, screen printing, ink jet forming, gel casting, filter film forming, slip casting or the like.
In addition, when used for an SOFC air electrode or the like, which will be described later, at the time of molding, polymer beads or fibrous polymers may be included to form certain pores in the resulting molded body.

The composite ceramic powder molded body thus obtained is subjected to the second stage of the composite ceramic material production process, that is, zirconia particles having a size of about 10 nm to 400 nm are sintered to form a three-dimensional network skeleton structure. A composite ceramic material can be obtained by heat treatment at the temperature and time for forming the body. As the heat treatment temperature in this second stage, for example, the lower limit value may be about 800 ° C. to 1000 ° C.
In this way, A _1-x B _x C _1-y D _y O _3-δ is formed on the surface of a three-dimensional network skeleton structure having a specific shape and bonded with zirconia particles made of yttria-stabilized zirconia. The composite ceramic material of the present embodiment in which the represented oxide is bonded can be produced.

[Solid oxide fuel cell]
The solid oxide fuel cell of the present embodiment uses the above composite ceramic material as an electrode material for an air electrode of a solid oxide fuel cell (SOFC). The electrode material is an oxide represented by the surface of the three-dimensional reticulated skeleton structure zirconia particles consisting of yttria-stabilized zirconia is bound _{A 1-x B x C 1} -y D y O 3-δ binding since it has a structure, three-phase interfaces large amount, expressed in the zirconia skeleton derived ionic conductivity, a _{1-x B} along the backbone of the zirconia _{x C 1-y D y O} 3-δ It is possible to provide a solid oxide fuel cell including an air electrode having high electronic conductivity derived from an oxide network.
Therefore, it is possible to improve the generation of oxygen ions by the reduction of oxygen, which is the cathode reaction of SOFC, and to improve the output characteristics of SOFC.

FIG. 1 is a schematic diagram showing an electrochemical characteristic evaluation apparatus, which is an apparatus for measuring the electric characteristics of the fuel electrode of the solid oxide fuel cell.
In the figure, 1 is an electrolyte such as yttria-stabilized zirconia, 2 is a reference electrode made of platinum (Pt), and 3 is made of La _0.8 Sr _0.2 MnO ₃ (LSM) formed on the upper surface of the electrolyte 1. The air electrode 4 is a fuel electrode made of nickel oxide-yttria stabilized zirconia or the like formed on the lower surface of the reference electrode 2, 5 is a platinum net disposed on each of the air electrode 3 and the fuel electrode 4, and 6 is a glass seal. , 7 and 8 are coaxially disposed alumina tubes having different diameters, 9 is a platinum wire, 10 is dry air, and 11 is a humidified hydrogen gas having a composition of 3% 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.

As described above, according to the composite ceramic material of the present embodiment, zirconia particles composed of yttria-stabilized zirconia are combined to form a three-dimensional network skeleton structure, and A _1-1 is formed on the surface of the network skeleton structure. since was coupled oxide represented by _{x B x C 1-y D} y O 3-δ, many three-phase interfaces weight, ionic conductivity from zirconia skeleton, a _1-x along the backbone of the zirconia it is possible to provide a _{B x C 1-y D y} O 3-δ as a raw material for SOFC air electrode with a network from a high electronic conductivity of the oxide represented by excellent composite ceramic material.

According to the method for producing a composite ceramic material of the present embodiment, zirconia fine particles composed of yttria-stabilized zirconia, and A _1-x B _x C _1-y D _y O _3-δ (where A is La, Sm, and One or more elements selected from the group of Fe, B is one or two elements selected from the group of Sr and Ni, C is one or two elements selected from the group of Co and Mn The seed element, D, is one or two elements selected from the group of Fe and Ni (however, different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 1 or 2 or more selected from the group of A, B, C, and D among the elements contained in the oxide represented by ≦ δ ≦ 1 and containing constant oxygen defects when 0 <δ The hydrogen ion index of the zirconia fine particle dispersion containing the above ions is adjusted to 4 or more and less than 7 By aggregating the zirconia fine particles into a three-dimensional network aggregate structure, and then adjusting the hydrogen ion index of the dispersion containing the network aggregate structure composed of the zirconia fine particles to 7 or more. the the surface of the mesh-like aggregate structure consisting of zirconia fine the _{a 1-x B x C 1} -y D y O 3-δ oxide precursor to precipitate caused by heat treatment represented, then The zirconia fine particle aggregate structure in which the precursor produced by heat treatment of the oxide represented by A _1-x B _x C _1-y D _y O _3-δ is a temperature of 800 ° C. or higher and 1300 ° C. or lower. since it was decided to heat treatment at a composite canceller coupled an oxide represented by the surface of the three-dimensional reticulated skeleton structure of the zirconia fine particles _{a 1-x B x C 1} -y D y O 3-δ The box material, can be easily and inexpensively manufactured.

According to the solid oxide fuel cell of the present embodiment, since the composite ceramic material of the present embodiment is an electrode material for the air electrode, the amount of three-phase interface is large, and the ionic conductivity derived from the zirconia skeleton, the zirconia skeleton O ₁ by reduction of oxygen, which is the air electrode reaction of SOFC, because it has high electron conductivity derived from the oxide network represented by A _1-x B _x C _1-y D _y O _3-δ Can be made more efficient, and SOFC output characteristics can be improved.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.

"Example 1"
Dispersion average particle diameter of 4 nm 8.5 mol% yttria-stabilized zirconia (8.5YSZ) dispersion (solid content concentration of 8.5YSZ: 2.56 wt%, pH: 3.3) in 312.5 g, La _{0 .8} Sr _0.2 MnO _{3 to have} a composition of lanthanum nitrate [La (NO ₃ ) ₃ .6H ₂ O] 12.46 g, strontium nitrate [Sr (NO ₃ ) ₂ ] 1.54 g, manganese nitrate [Mn _{(NO 3)} the 2 · 6H ₂ O] 13.02g was dissolved in pure water 407.2G, La adjusted to pH2.0 with nitric acid, by adding a metal salt aqueous solution of Sr and Mn stirring, La, Sr, and An Mn ion-containing 8.5 mol% yttria-stabilized zirconia (LSM-8.5YSZ) dispersion (pH: 2.70) was prepared.

Subsequently, 28-30% ammonia water was added to this LSM-8.5YSZ dispersion, and the pH of this dispersion was adjusted to 5.0 to obtain Solution A-1.
Next, a 0.4 mol / L aqueous solution of ammonium hydrogen carbonate (NH ₄ HCO ₃ ) was dropped into the solution A-1, the pH of the solution A-1 was adjusted to 8, and a solution B-1 was obtained.

Next, the solid content is separated from the solution B-1 using a filtration and washing device, the solid content is washed with water four times to remove impurity ions, and then the solvent is replaced with ethanol. It was dried at 80 ° C. for 24 hours. Next, the obtained dried product was pulverized in a mortar and heat treated at 1000 ° C. for 6 hours in an electric furnace, and La _0.8 Sr _0.2 MnO ₃ (LSM) was applied to the surface of yttria-stabilized zirconia (YSZ). The combined composite ceramic powder C-1 was obtained.
The masses of La, Sr, Mn, Y and Zr in the composite ceramic powder C-1 were measured by fluorescent X-ray analysis, and La _0.8 Sr _0.2 MnO ₃ (LSM) and yttria were measured based on the measurement results. The mass ratio with stabilized zirconia (YSZ) was calculated. As a result, the mass ratio (LSM: YSZ) was 46:54.

  Next, nickel oxide (Nikko Rica; TYPE-F) 0.98 g, yttria stabilized zirconia (Tosoh; TZ-8YS) 0.52 g, polyethylene glycol (molecular weight: 400) 0.5 g and ethanol 10 g in a ball mill. Then, this mixed solution was heated to 80 ° C. to evaporate and remove ethanol to prepare a nickel oxide-yttria stabilized zirconia paste. Next, this paste was applied by screen printing onto an 8 mol% yttria stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, and then fired at 1350 ° C. for 2 hours to form a fuel electrode on the 8YSZ substrate.

  Next, 1.5 g of the composite ceramic powder C-1 was 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 was heated to 80 ° C. to obtain ethanol. Was removed by evaporation to prepare an LSM paste. Next, this LSM paste was applied by screen printing onto an 8 mol% yttria-stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, and then baked at 1100 ° C. for 2 hours, and an air electrode D-1 was formed on the 8YSZ substrate. Formed. Further, a platinum wire was wound around the side surface of the 8YSZ substrate to form a reference electrode.

Subsequently, the electrode reaction resistance of this air electrode was measured using the electrochemical property evaluation apparatus shown in FIG. Here, dry air is supplied to the air electrode and the reference electrode, and humidified hydrogen gas having a composition of 3% H ₂ O-97% H ₂ is supplied to the fuel electrode at a flow rate of 50 mL / min. The electrode reaction resistance of the air electrode was evaluated by measuring the AC impedance between the reference electrode and the air electrode. The measurement temperature was 800 ° C., and the measurement frequency was 10 kHz to 0.1 Hz. As a result of the measurement, the electrode reaction resistance of the air electrode was 190 mΩ · cm ² .

FIG. 2 shows a transmission electron microscope (TEM) image showing the air electrode D-1 of Example 1 in the upper part, and the air electrode D- of Example 1 obtained by the energy dispersive X-ray spectrometer (EDX) in the lower part. 1 is a diagram showing an element distribution of 1. FIG.
According to FIG. 2, yttria-stabilized zirconia (YSZ) particles of about 200 nm are aggregated to form a three-dimensional network structure. La _0.85 Sr _0.15 MnO ₃ ( LSM) can be seen to have a structure in which La, Sr, Mn and YSZ are intertwined.

"Example 2"
To 312.5 g of an 8.5 mol% yttria-stabilized zirconia (8.5 YSZ) dispersion (8.5 YSZ solid content concentration: 2.56 mass%, pH: 3.3) having a dispersion average particle size of 6.5 nm, Lanthanum nitrate [La (NO ₃ ) ₃ .6H ₂ O] 12.46 g, strontium nitrate [Sr (NO ₃ ) ₂ ] 1.54 g, manganese nitrate to have a composition of La _0.8 Sr _0.2 MnO ₃ Dissolve 13.02 g of [Mn (NO ₃ ) ₂ .6H ₂ O] in 407.2 g of pure water, add an aqueous solution of La, Sr, and Mn metal salts adjusted to pH 2.0 with nitric acid, and stir La, A 8.5 mol% yttria-stabilized zirconia (LSM-8.5YSZ) dispersion (pH: 2.70) containing ions of Sr and Mn was prepared.

Next, 28-30% ammonia water was added to this LSM-8.5YSZ dispersion, and the pH of this dispersion was adjusted to 5.0 to obtain Solution A-2.
Next, a 0.4 mol / L aqueous solution of ammonium hydrogen carbonate (NH ₄ HCO ₃ ) was added dropwise to the solution A-2, and the pH of the solution A-2 was adjusted to 8 to obtain a solution B-2.

Next, the solid content is separated from the solution B-2 using a filtration and washing device, this solid content is washed with water four times to remove impurity ions, and then the solvent is replaced with ethanol. It was dried at 80 ° C. for 24 hours. Next, the obtained dried product was pulverized in a mortar and heat-treated at 800 ° C. for 6 hours in an electric furnace, and La _0.8 Sr _0.2 MnO ₃ (LSM) was applied to the surface of yttria-stabilized zirconia (YSZ). A combined composite ceramic powder C-2 was obtained.
The masses of La, Sr, Mn, Y, and Zr in this composite ceramic powder C-2 were measured by fluorescent X-ray analysis, and La _0.8 Sr _0.2 MnO ₃ (LSM) and yttria were measured based on the measurement results. The mass ratio with stabilized zirconia (YSZ) was calculated. As a result, the mass ratio (LSM: YSZ) was 48:52.

  Next, nickel oxide (Nikko Rica; TYPE-F) 0.98 g, yttria stabilized zirconia (Tosoh; TZ-8YS) 0.52 g, polyethylene glycol (molecular weight: 400) 0.5 g and ethanol 10 g in a ball mill. Then, this mixed solution was heated to 80 ° C. to evaporate and remove ethanol to prepare a nickel oxide-yttria stabilized zirconia paste. Next, this paste was applied by screen printing onto an 8 mol% yttria stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, and then fired at 1350 ° C. for 2 hours to form a fuel electrode on the 8YSZ substrate.

  Next, 1.5 g of the composite ceramic powder C-2 was 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 was heated to 80 ° C. to obtain ethanol. Was removed by evaporation to prepare an LSM paste. Next, this LSM paste was applied by screen printing onto an 8 mol% yttria-stabilized zirconia (8YSZ) substrate having a thickness of 300 μm, and then baked at 1100 ° C. for 2 hours, and an air electrode D-2 was formed on the 8YSZ substrate. Formed. Further, a platinum wire was wound around the side surface of the 8YSZ substrate to form a reference electrode.

Subsequently, the electrode reaction resistance of this air electrode was measured using the electrochemical property evaluation apparatus shown in FIG. Here, dry air is supplied to the air electrode and the reference electrode, and humidified hydrogen gas having a composition of 3% H ₂ O-97% H ₂ is supplied to the fuel electrode at a flow rate of 50 mL / min. The electrode reaction resistance of the air electrode was evaluated by measuring the AC impedance between the reference electrode and the air electrode. The measurement temperature was 800 ° C., and the measurement frequency was 10 kHz to 0.1 Hz. As a result of the measurement, the electrode reaction resistance of the air electrode was 230 mΩ · cm ² .

FIG. 3 is a scanning electron microscope (SEM) image showing the air electrode D-2.
As can be seen from FIG. 3, fine particles of about 200 nm aggregate to form a three-dimensional network structure.

"Comparative Example 1"
0.75 g of 8.5 mol% yttria-stabilized zirconia (8.5YSZ) powder having a crystallite diameter of 35 nm and LSM powder having a crystallite diameter of 22 nm (La _0.85 Sr _0.15 MnO ₃ manufactured by AGC Seimi Chemical Co.) 0 A total of 1.5 g of .75 g was 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 was heated to 80 ° C. to evaporate and remove ethanol. A yttria-stabilized zirconia paste was prepared.
Next, it was applied by screen printing as in Example 1, and then baked at 1350 ° C. for 2 hours. On the opposite surface of the fuel electrode formed on the 8 mol% yttria-stabilized zirconia substrate having a thickness of 300 μm, LSM-yttria Stabilized zirconia paste was applied by screen printing. First, when it was heat-treated at 1150 ° C. for 2 hours, it did not sinter sufficiently, so it was fired at 1200 ° C. for 2 hours to form an air electrode D-3.

Next, a reference electrode was produced according to Example 1. The electrode reaction resistance of the air electrode was measured according to Example 1. As a result of the measurement, the electrode reaction resistance of the fuel electrode was 900 mΩ · cm ² .
FIG. 4 is a scanning electron microscope (SEM) image showing the air electrode D-3 of Comparative Example 1.
FIG. 4 shows that the particles are coarsened to about 500 nm.

"Comparative Example 2"
8.0 g of commercially available 8 mol% yttria-stabilized zirconia (8YSZ, manufactured by Tosoh Corporation; TZ-8YS) was added to 304.5 g of dilute nitric acid having a pH of 3.3 and dispersed using an ultrasonic homogenizer to prepare a dispersion ( 8YSZ solid content concentration: 2.56% by mass). The dispersion average particle diameter of the yttria-stabilized zirconia powder in this dispersion was 120 nm. To this _dispersion, La _{0.8 Sr} 0.2 lanthanum nitrate so as to have the composition of MnO _{3 [La (NO 3) 3 · 6H} 2 O ] 12.46 g, strontium nitrate [Sr _{(NO 3) 2]} 1 .54 g, manganese nitrate [Mn (NO ₃ ) ₂ .6H ₂ O] 13.02 g was dissolved in 407.2 g of pure water, and a metal salt aqueous solution of La, Sr and Mn adjusted to pH 2.0 with nitric acid was added. The mixture was stirred to prepare an 8.5 mol% yttria-stabilized zirconia (LSM-8.5YSZ) dispersion (pH: 2.80) containing La, Sr and Mn ions.

  Next, 28-30% aqueous ammonia was added to the LSM-8.5YSZ dispersion, and the pH of the dispersion was adjusted to 8.0 to obtain Solution B-4.

Next, using a filtration washing apparatus, the solid content is separated from the solution B-4. The solid content is washed with water four times to remove impurity ions, and then the solvent is replaced with ethanol. It was dried at 80 ° C. for 24 hours. Next, the obtained dried product was pulverized in a mortar and heat treated at 1000 ° C. for 6 hours in an electric furnace, and La _0.8 Sr _0.2 MnO ₃ (LSM) was applied to the surface of yttria-stabilized zirconia (YSZ). The combined composite ceramic powder C-4 was obtained.
The masses of La, Sr, Mn, Y and Zr in this composite ceramic powder C-4 were measured by fluorescent X-ray analysis. Based on the measurement results, La _0.8 Sr _0.2 MnO ₃ (LSM) and yttria were measured. The mass ratio with stabilized zirconia (YSZ) was calculated. As a result, the mass ratio (LSM: YSZ) was 48:52.

Next, an air electrode, a fuel electrode, and a reference electrode were produced according to Example 1 using the above powder.
Subsequently, the electrode reaction resistance of this air electrode was measured according to Example 1. As a result of the measurement, the electrode reaction resistance of the fuel electrode was 750 mΩ · cm ² .
FIG. 5 is a scanning electron microscope (SEM) image showing the air electrode D-3 of Comparative Example 1.
FIG. 5 shows that the particles are coarsened to about 600 to 800 nm.

In the composite ceramic material of the present invention, zirconia particles made of yttria-stabilized zirconia are combined to form a three-dimensional network skeleton structure. A _1-x B _x C _1-y D is formed on the surface of the network skeleton structure. _y O _3-δ (wherein A is one or more elements selected from the group of La, Sm and Fe, B is one or two elements selected from the group of Sr and Ni, C is one or two elements selected from the group of Co and Mn, D is one or two elements selected from the group of Fe and Ni (however, different from A); 2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ ≦ 1, and a constant vacancy is contained when 0 <δ), whereby zirconia particles are bonded distribution of and _{a 1-x B x C 1} -y D y O oxide represented by _3-[delta], the composition system This is a composite ceramic powder that has excellent electrical properties, has many three-phase interfaces, and has excellent electronic conductivity. Therefore, it can be used in solid oxide fuel cells and various industrial fields. is there.

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)

Zirconia particles made of yttria-stabilized zirconia are combined to form a three-dimensional network skeleton structure, and A _1-x B _x C _1-y D _y O _3-δ (wherein , A is one or more elements selected from the group of La, Sm and Fe, B is one or two elements selected from the group of Sr and Ni, and C is from the group of Co and Mn One or two elements selected, D is one or two elements selected from the group of Fe and Ni (however, different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ ≦ 1, and an oxide represented by the formula (containing a constant oxygen defect when 0 <δ).   2. The composite ceramic material according to claim 1, wherein the zirconia particles have an average particle diameter of 10 nm or more and 400 nm or less. The ratio (W _ABCD / W _YSZ ) of the mass (W _ABCD ) of the A _1-x B _x C _1-y D _y O _{3-δ to} the mass (W _YSZ ) of the zirconia particles is 5/95 or more and 95 The composite ceramic material according to claim 1 or 2, wherein the composite ceramic material is / 5 or less. And zirconia fine particles made of yttria-stabilized _zirconia, A in _{1-x B x C 1-} y D y O 3-δ ( wherein, A is La, 1 or more kinds of selected from the group consisting of Sm and Fe Element, B is one or two elements selected from the group of Sr and Ni, C is one or two elements selected from the group of Co and Mn, D is selected from the group of Fe and Ni 1 or 2 elements (but different from A), 0.2 ≦ x ≦ 0.9, 0 ≦ y ≦ 1, 0 ≦ δ ≦ 1, and constant when 0 <δ Hydrogen ion index of zirconia fine particle dispersion containing one or more ions selected from the group of A, B, C and D among the elements contained in the oxide represented by (containing oxygen defects) Is adjusted to 4 or more and less than 7 to agglomerate the zirconia fine particles to form a three-dimensional And then adjusting the hydrogen ion index of the dispersion containing the network aggregate structure composed of the zirconia fine particles to 7 or more to thereby form the network aggregate structure composed of the zirconia microparticles. A precursor produced by heat treatment of the oxide represented by the A _1-x B _x C _1-y D _y O _3-δ is deposited on the surface, and then the A _1-x B _x C _1-y D _The zirconia fine particle aggregate structure in which the precursor produced by heat treatment of the oxide represented by _{y 2} O _{3 -δ} is heat-treated at a temperature of 800 ° C. or higher and 1300 ° C. or lower to form the zirconia fine particle aggregate structure. wherein _{a 1-x B x C 1} -y D y O oxide represented by _3-[delta] on the surface of the reticulated skeleton structure of the zirconia fine three-dimensional zirconia particles obtained by sintering the bond The method of producing a composite ceramic material and generating a composite ceramic material.   5. The method for producing a composite ceramic material according to claim 4, wherein a dispersion average particle diameter of the zirconia fine particles in the zirconia fine particle dispersion is 0.1 nm or more and 30 nm or less.   A solid oxide fuel cell comprising the composite ceramic material according to claim 1 or 2 as an air electrode material.