JP2001023653A - Compact solid electrolyte film, solid electrolyte type fuel cell containing the same and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase economical efficiency and mass productivity, to facilitate applications to large areas, to decrease resistance and to enhance homogeneity and compactness by using a solid electrolyte powder that includes a plurality of powders having different average specific surface areas. SOLUTION: When a solid electrolyte powder contains first and second powders, the average specific surface area of these is preferably set in the range of 0.2-50 cm2/g. The difference of the average specific surface area between the first and second powders is preferably set 1:1.5 or more. Thereby, the filling degree of the solid electrolyte powder itself becomes compact. When the first powder has the average specific surface area smaller than that of the second powder, the first powder is preferably mixed more than the second powder when mixing. Consequently, the structure of an electrolyte film is formed with the first powder, allowing the firing shrinkage to be suppressed. As the result, cracks in the electrolyte film are avoided and damages to a substrate can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dense solid electrolyte membrane formed on porous ceramics, such as a solid electrolyte thin film of a solid oxide fuel cell (hereinafter also referred to as SOFC), and a method for producing the same. In particular, the present invention relates to a dense solid electrolyte membrane capable of obtaining a homogeneous and dense thin film with low resistance by an inexpensive manufacturing method, a solid oxide fuel cell including the same, and a manufacturing method thereof.

[0002]

2. Description of the Related Art The prior art of a method for forming a dense electrolyte membrane will be described by taking a solid electrolyte thin film for SOFC as an example. SOFC
Has oxygen ion (O ²⁻ ) permeability, and
A solid electrolyte thin film having no gas permeability is required. This solid electrolyte thin film (ZrO ₂ , CeO _2, etc.) is required to be thin and dense in order to satisfy both these characteristics. Furthermore, it is also required that a large-area thin film can be formed economically. In the power generation cell of this SOFC, a solid electrolyte membrane having a thickness of 30 to 2000 μm is generally formed on a porous substrate having a thickness of 0.3 to 5.0 mm. Further, a fuel electrode (Ni-based cermet or the like) is formed thereon.

The following has been proposed with the aim of obtaining a thin, dense, low-cost, and highly mass-producible solid electrolyte thin film for an SOFC cell. Production method by CVD / EVD (Chemical Electrodeposition) (JP-A-61-91880): In this production method, a first electrode is attached to a porous support, and a conductive and oxygen-permeable intermediate substance is produced. By depositing on the first electrode, the first electrode is protected from high-temperature metal halide vapor, and the intermediate layer material is brought into contact with the high-temperature metal halide vapor to cover the entire surface of the intermediate layer with metal oxide. To form a solid electrolyte.

[0004] Manufacturing method by plasma spraying (JP-A-6
No. 1-198570): This production method is to form a solid electrolyte material comprising zirconium oxide and a metal oxide such as a rare earth element, then to pulverize the solubilized raw material, and to obtain a solid electrolyte obtained by the pulverization. After adjusting the particle size of the powder,
It is characterized in that it is deposited as an electrolyte thin film on the base of a fuel cell by plasma spraying. According to the example in the specification of the publication, a spray powder having a particle size of
It is alleged that a solid electrolyte thin film having a thickness of 00 μm and a terminal voltage of 790 mV was obtained.

[0005] Manufacturing method by slurry application (Japanese Unexamined Patent Publication No.
No. 93065): In this production method, one of the air electrode layer and the fuel electrode layer is formed in a cylindrical shape, and the powder slurry of the electrolyte and the other materials constituting the other electrode layers is formed into a cylindrical material. The method is characterized in that the surface is sequentially applied and dried, and then fired. According to the embodiment of the publication, a thickness of 150 μm
It is said that m YSZ films were obtained.

[0006] Production method by spraying + slurry filler (JP-A-2-220361): This production method is applied to a solid electrolyte layer formed by thermal spraying on a base tube.
It is characterized in that after applying a filler containing yttria-stabilized zirconia at a solid concentration of 40% by weight or more, drying and firing are performed. According to the example of the publication, a particle diameter of 0.05 to 100 μm is applied to an air plasma sprayed film having a thickness of 100 μm.
It is said that a 2.5 μm YSZ powder-containing slurry was applied (hand-painted with a brush), dried and fired to obtain a solid electrolyte thin film having an extremely low air permeability.

[0007]

The above-mentioned prior arts have the following problems. -CVD method-EVD method: This method is suitable for forming a dense thin film. However, it is necessary to perform the film formation under a special atmosphere and physical conditions shielded from the atmosphere, so that an expensive apparatus is required. For a large member, a large device capable of accommodating the member is required. Therefore, it is difficult to apply a film to a large member, the productivity is low, and the cost is high. In addition, since corrosive raw material gas is used, there is a high risk of the base being corroded. -Plasma spraying method: The film formed by this method is basically porous. Therefore, in order to eliminate air permeability, it is necessary to form a thick film to some extent. Therefore, a high-performance cell cannot be obtained. In addition, mass productivity is low. Slurry coating method: This is an economical method because the film forming operation can be performed in the atmosphere and no expensive equipment is required. But,
It was said that there was a problem in the denseness and thinning of the film. In fact,
The solid electrolyte thin film disclosed as an example in JP-A-2-220361 has a thickness of 200 μm, which is considerably thicker than the development target of this type of film of 10 to 50 μm. In addition, since the firing of the film was apt to occur, a plurality of firings were required to achieve densification while filling the cracks. In order to solve such problems, raising the sintering temperature and pulverizing the slurry powder have been studied to increase the sinterability of the film material.However, in the former case, the reaction between the substrate and the solid electrolyte is problematic. And the latter is 0.1μ
It was difficult to produce a large amount of fine powder having a particle size of m or less. -Thermal spraying + slurry filling method: The film thickness tends to become thicker with the double process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a homogeneous and dense solid electrolyte thin film which is excellent in economy and mass productivity, can be easily applied to a large area, has low resistance, and has a low resistance.

[0009]

In order to achieve the above object, the present invention provides a dense solid electrolyte membrane formed by forming a solid electrolyte membrane made of a solid electrolyte powder on an electrode substrate. The electrolyte powder includes a plurality of powders having different average specific surface areas (average particle diameters).

In firing on a substrate, if the stress due to firing shrinkage is greater than the strength of the substrate, the substrate will be deformed or damaged. On the other hand, when the stress due to firing shrinkage is small, cracks occur in the solid electrolyte membrane itself, or sufficient denseness cannot be obtained. Therefore, in order to sinter the solid electrolyte membrane itself without applying a large stress to the fired substrate, it is extremely effective to use the first and second powders having different average specific surface areas.

Further, by mixing the first and second powders, there is also an effect that the filling degree of the solid electrolyte powder itself is increased.

The manufacturing method according to the present invention is characterized in that a slurry containing the first and second powders is prepared, and then this slurry is formed on an electrode substrate.

By using the first and second powders having different average specific surface areas, it becomes possible to control the sinterability of the solid electrolyte powder.

As the solid electrolyte powder, zirconia-based, ceria-based, and other solid electrolyte materials that are stable at high temperatures include Y ₂ O ₃ , Yb ₂ O ₃ , Dy ₂ O ₃ , Er ₂ O ₃ , Eu ₂ O ₃ , G
_{d 2 O 3, Ho 2 O} 3, Lu 2 O 3, of the _{Sm 2 O 3, Tm 2 O} 3 elements, adding at least 1 or more.

The second manufacturing method according to the present invention is characterized in that La (S
r, Ca) MnO ₃ perovskite oxide (LSC
M) and a slurry containing a composite powder (LSCM / YSZ) of yttria-doped zirconia (YSZ) is formed on the cathode base, and the film on the cathode base contains the first and second powders. It is characterized in that a slurry is formed into a film.

According to the second manufacturing method, it is possible to further increase the interface conductivity between the air electrode and the solid electrolyte.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The solid electrolyte powder (first and second powders) according to the present invention has an average specific surface area of 0.5.
A plurality of powders are arbitrarily selected from powders of ^{2 to} 50 m ² / g and used. If a powder having an average specific surface area smaller than 0.2 m ² / g is used, it is difficult to produce a dense solid electrolyte membrane because the sinterability is too low. Further, when a powder having an average specific surface area of more than 50 m ² / g is used, cracks are generated in the solid electrolyte membrane or firing shrinkage of the solid electrolyte powder occurs during firing on the electrode base because the sinterability is too high. This is because the accompanying stress occurs and damages the base. Preferably, the average specific surface area of the solid electrolyte powder is about 3 to 20 m ² / g.

It has been confirmed by experiments by the present inventors that if the difference between the average specific surface areas of the first and second powders is 1: 1.5 or more, the filling degree of the solid electrolyte powder itself becomes high. I have.

The reason for mixing the first powder more than the second powder as the solid electrolyte powder in the present invention is that the first powder forms the skeleton of the electrolyte membrane and controls the firing shrinkage, thereby obtaining the solid electrolyte. This is because cracks in the film can be suppressed and damage to the substrate can be suppressed.

The solid electrolyte membrane is produced by laminating a plurality of solid electrolyte membranes comprising the first and second powders in a layer. This is because a dense solid electrolyte membrane can be obtained without causing damage to the substrate by preferentially causing firing shrinkage in the film thickness direction (perpendicular to the substrate). In this case, to the plurality of layers forming the solid electrolyte membrane, a layer made of a third or fourth powder having a different average specific surface area from the first or second powder is added, or the first or second powder is added. A plurality of layers made of powder may be alternately stacked to form a three-layer or four-layer structure. Further, a layer of the solid electrolyte membrane may be prepared by mixing a powder having an average specific surface area different from those of either or both of the first and second powders.

Here, assuming that the thickness of the solid electrolyte membrane made of the first powder is larger than the thickness of the solid electrolyte membrane made of the second powder, the skeleton of the electrolyte membrane formed by the first powder is assumed. Can be further strengthened, so that control of firing shrinkage, suppression of cracks in the solid electrolyte membrane, and suppression of damage to the substrate can be further ensured.

It is preferable that a solid electrolyte film made of the first powder is formed on the electrode substrate, and a solid electrolyte film made of the second powder is formed on the solid electrolyte film. By first forming a slurry containing the first powder on the electrode substrate, the firing shrinkage of the electrolyte during firing of the electrolyte film is small, causing damage to the substrate or causing excessive reaction between the electrode substrate and the electrolyte film. This is because that can be prevented. In addition,
When the electrode base is cylindrical, square tube, etc., "on the electrode base"
Means the "surface of the electrode substrate".

The thickness of the solid electrolyte membrane is 5 to 150
μm is desirable. If the thickness is 5 μm or less, a sufficiently dense film cannot be obtained, while if it is 150 μm or more, the internal resistance is too large. Preferably, 100 μm
Or less, more preferably 50 μm or less. This film thickness does not need to be changed according to the change in the average specific surface area of the first and second powders and the difference between the average specific surface areas of the first and second powders.

The first and second powders may be prepared by mixing a plurality of solid electrolyte powders having different average specific surface areas. When the first powder is prepared by mixing a plurality of solid electrolyte powders having different average specific surface areas, the average specific surface area of the plurality of solid electrolyte powders is smaller than the average specific surface area of any of the second powders. To be. On the other hand, when the second powder is prepared by mixing a plurality of solid electrolyte powders having different average specific surface areas, the average specific surface area of each of the plurality of solid electrolyte powders is larger than the average specific surface area of the first powder. To be larger. Further, in addition to the first and second powders, third and fourth solid electrolyte powders having different average specific surface areas from these powders may be added to form a solid electrolyte membrane.

The slurry using the solid electrolyte powder can be obtained by grinding and mixing with a ceramic ball to obtain a homogeneous slurry.

The sintering temperature of the solid electrolyte membrane is 1200 ° C. to 1
The reason for setting the temperature at 700 ° C. is that if the firing is performed at a temperature lower than 1200 ° C., the sintering of the solid electrolyte powder does not proceed sufficiently, so that a dense solid electrolyte membrane cannot be obtained.
In addition, when firing at a temperature higher than 1700 ° C., the porosity of the electrode substrate is lost. Desirably 1400
C. to about 1500.degree.

Solid electrolytes such as zirconia and ceria
In the material, Y_TwoO_Three, Yb_TwoO_Three, Dy_TwoO_Three, Er
_TwoO_Three, Eu_TwoO_Three, Gd_TwoO_Three, Ho_TwoO_Three, Lu_TwoO_Three, Sm
_TwoO_Three, Tm_TwoO_ThreeAt least one of the elements is 3 to 2
0 mol% should be contained.
This is because the range is excellent. Desirably, 8 to 12 m
ol%. Further, more preferably, a zirconia-based solid
In the body electrolyte material, Y _TwoO_ThreeContains 8 to 12 mol%
Let

In the present invention, the content of the solid electrolyte powder in the slurry is from 10 parts to 100 parts of the slurry solution.
50 parts are preferred. The composition of the slurry solution of the slurry in the present invention is not particularly limited. The slurry may include solvents, binders, dispersants, defoamers, and the like. However, it is desirable that a non-volatile solvent be contained as a solvent in an amount of 10 to 80% by weight of the slurry solvent. The effect of the hardly volatile solvent is to suppress a change in viscosity of the slurry during preparation and storage of the slurry, and to suppress the occurrence of cracks due to drying after film formation (for example, dipping) using the slurry. It is. Here, the degree of low volatility is, for example, 1 when the volatility of butyl acetate is 100.
The following is desirable. For example, α-terpineol and the like can be mentioned.

The slurry solution may contain a general volatile solvent in addition to the non-volatile solvent. The action of the solvent contained in the solution is to improve the dispersibility of the solid electrolyte powder and the defoaming property. As an example of such a solvent, ethyl alcohol is suitable, and its desirable content is 20 to 90 wt% of the slurry solution.

The function of the binder contained in the slurry solution is to improve the coating property (adhesion) of the solid electrolyte powder on the substrate. The amount of the binder is preferably 0.1 to 10 parts based on 100 parts of the solvent. The reason is that if the concentration is low (less than 0.1 wt%), the coating property is low, and if the concentration is high (more than 10 wt%), the dispersibility of the solid electrolyte powder is deteriorated. As a specific example of the binder, ethyl cellulose is suitable.

The action of the dispersant contained in the slurry solution is as follows:
This is an improvement in the dispersibility of the solid electrolyte powder. The amount of dispersant is
0.1 to 4 parts is preferable for 100 parts of the solvent. The reason is that if the concentration is low (less than 0.1 wt%), the dispersibility is low,
If the concentration is high (over 4 wt%), the slurry is likely to be denatured. Specific examples of the dispersant include polyoxyethylene alkyl phosphate.

The antifoaming agent contained in the slurry solution has the function of eliminating air bubbles in the slurry. The amount of the defoamer is 10
0.1 to 4 parts is preferable to 0 part. The reason is that if the concentration is low (less than 0.1 wt%), the effect is not so expected, and if the concentration is high (more than 4 wt%), the slurry is likely to be denatured. Specific examples of the antifoaming agent include sorbitan sesquioleate. The preparation and mixing of each agent / solid electrolyte powder can employ a method such as a ball mill.

The method of applying the slurry to the substrate in the production method of the present invention is not particularly limited, and may be a dipping method, a spray method, a brush coating method, or the like. Among them, the dipping method is particularly preferred. Simple, rich in mass production,
Because it is low cost. As the dipping method, besides a normal dipping method in which a substrate is immersed in a slurry in the air, a dipping method in a pressurized gas or a vacuum can be adopted. In that case, the number of times of dipping can be selected according to the required film thickness and the slurry composition to be used.

[0034]

Example 1 10 mol% of commercially available solid electrolyte powder
Yttria-added zirconia powder (specific surface area 10 m ² /
g) and a specific surface area of 1 by a ball mill using unmilled powder (BET10 powder) and ceramic balls.
Powder crushed to 8 m ² / g (BET18 powder)
Was prepared. Using these powders, the ratio of BET10 powder to BET18 powder was 100: 0, 95: 5, 90: 1.
0, 80:20, 70:30, 50:50, 30: 7
0, 20:80, 0: 100, and 10 parts of the mixed powder, 4.8 parts of a binder, 85.1 parts of a solvent,
Nine kinds of slurries were prepared by mixing 0.1 part of a surfactant. Using this slurry, an air electrode substrate having an average pore diameter of 10 μm (outer diameter φ22 mm × wall thickness 2 mm × length 1000)
mm), a film was formed by dipping so as to have a thickness of about 50 μm, and baked at 1400 ° C. for 5 hours. The sample after film formation and baking is subjected to 1 kgf / cm
^The gas permeation amount was measured under the differential pressure of ² , and the gas permeation coefficient was converted. Table 1 and FIG. 1 show the relationship between the gas permeability coefficients when using slurries having different BET18 powder ratios.

[0035]

[Table 1]

From the gas permeation coefficient results calculated from the gas permeation amount measurement, two solid electrolyte powders having different average specific surface areas were used.
It has been found that by mixing the types, the denseness of the solid electrolyte membrane can be improved. As for the mixing ratio, it has been found that the denseness is more improved when a powder having a small average specific surface area is mixed more than a powder having a large average specific surface area.

[0037]

Example 2 Commercially available 10 mol% as solid electrolyte powder
Yttria-added zirconia powder (specific surface area 10 m ² /
g) and a specific surface area of 1 by a ball mill using unmilled powder (BET10 powder) and ceramic balls.
Powder crushed to 8 m ² / g (BET18 powder)
Was prepared. Using these powders, 10 parts of the powder, 4.8 parts of the binder, 85.1 parts of the solvent, and 0.1 part of the surfactant were used.
Were mixed to prepare two types of slurries. Using these slurries, on an air electrode base (outer diameter φ22 mm × wall thickness 2 mm × length 1000 mm) with an average pore diameter of 10 μm,
A film was formed by dipping so that the solid electrolyte film thickness became about 50 μm, and baked at 1400 ° C. for 5 hours. As a film forming method, a slurry using BET10 powder was formed first on the air electrode base, and then a film was formed using slurry using BET18 powder. As shown in Table 2, the film thickness of the slurry using BET10 powder was adjusted to 50 μm, 45 μm, 40 μm, 35 μm, 25
μm, 10 μm, and 0 μm.

[0038]

[Table 2]

The gas permeation amount of the sample after film formation and firing was measured with a nitrogen gas under a pressure difference of 1 kgf / cm ² , and converted into a gas permeation coefficient. Table 3 and FIG. 2 show the gas permeation coefficient depending on the difference in the film thickness depending on the slurry using the BET10 powder.

[0040]

[Table 3]

From the gas permeation coefficient results calculated from the gas permeation amount measurement, two or more types of slurries of solid electrolyte powders having different average specific surface areas are formed in a layered manner on the electrode substrate to form a dense solid electrolyte membrane. It has been found that the property can be improved. Also, the film thickness of the slurry containing the solid electrolyte powder having a small average specific surface area,
It was found that the denser the film, the thicker the film formed than the film formed by the slurry containing the solid electrolyte powder having a large average specific surface area.

[0042]

Example 3 Commercially available 10 mol% as solid electrolyte powder
Yttria-added zirconia powder (specific surface area 10 m ² /
g) and a specific surface area of 1 by a ball mill using unmilled powder (BET10 powder) and ceramic balls.
Powder crushed to 8 m ² / g (BET18 powder)
Was prepared. Using these powders, 10 parts of the powder, 4.8 parts of the binder, 85.1 parts of the solvent, and 0.1 part of the surfactant were used.
Were mixed to prepare two types of slurries. Using these slurries, on an air electrode base (outer diameter φ22 mm × wall thickness 2 mm × length 1000 mm) with an average pore diameter of 10 μm,
A film was formed by dipping so that the solid electrolyte film thickness became about 50 μm, and baked at 1400 ° C. for 5 hours. As a film forming method, a slurry using BET10 powder was first formed on the air electrode base, and then a film using BET18 powder and a slurry using BET10 powder were alternately formed. As a comparison condition, BET1
Film formation was also performed using only slurry using 0 powder. The conditions of the film thickness were set to four types shown in Table 4.

[0043]

[Table 4]

The sample after film formation and firing was measured for gas permeation amount under a differential pressure of 1 kgf / cm ² with nitrogen gas, and converted into a gas permeation coefficient. Table 5 and FIG. 3 show the gas permeability coefficients of each sample.

[0045]

[Table 5]

From the gas permeation coefficient result calculated from the gas permeation amount measurement, the denseness of the solid electrolyte membrane is obtained by laminating two or more types of slurries of solid electrolyte powders having different average specific surface areas on the electrode substrate. Was found to be able to be improved.

[0047]

Example 4 10 mol% of commercially available solid electrolyte powder
Yttria-added zirconia powder (specific surface area 10 m ² /
g) and a specific surface area of 1 by a ball mill using unmilled powder (BET10 powder) and ceramic balls.
4 and 18 m ² / g powder (BET
14 powder and BET18 powder). Using these powders, BET10 powder alone, mixed powder weighed so that the ratio of BET10 powder to BET14 powder was 7: 3, and three kinds of powders of BET18 powder alone, a binder was added to 10 parts of powder. 4.8 parts, solvent 85.
One part and 0.1 part of a surfactant were mixed to prepare three kinds of slurries. Using these slurries, an average pore diameter of 1
A film was formed on a 0 μm air electrode substrate (outer diameter φ22 mm × wall thickness 2 mm × length 1000 mm) by a dipping method so as to have a solid electrolyte film thickness of about 50 μm.
The firing was performed for 5 hours. As shown in Table 6, BET10 powder alone and BET
A slurry using a mixed powder weighed so that a ratio of 10 powders to BET 14 powders is 7: 3 is used for each 40.
After forming a μm film, a 10 μm film was formed using a slurry using BET18 powder.

[0048]

[Table 6]

The sample after film formation and firing was measured for gas permeation amount under a differential pressure of 1 kgf / cm ² with nitrogen gas, and converted into a gas permeation coefficient. Table 7 and FIG. 4 show the gas permeability coefficients of each sample.

[0050]

[Table 7]

When two or more slurries of solid electrolyte powders having different average specific surface areas are layered on the electrode substrate from the gas permeability coefficient results calculated from the gas permeation amount measurement, the solid electrolyte having a small average specific surface area is used. It has been found that by mixing two or more kinds of powders having different specific surface areas, it is possible to further improve the denseness of the solid electrolyte membrane.

[0052]

As described above, according to the present invention, in a dense solid electrolyte membrane in which a solid electrolyte membrane made of a solid electrolyte powder is formed on an electrode substrate, the solid electrolyte powder has an average specific surface area (average specific surface area). By including a plurality of powders having different particle diameters, the packing property of the solid electrolyte powder can be made denser, and it is possible to control the sintering property to an appropriate level to obtain a dense solid electrolyte membrane. Can be.

Film formation by a slurry containing a plurality of solid electrolyte powders having different average specific surface areas can improve the filling property of the solid electrolyte powder, control firing shrinkage, and form bases (plates, pipe inner and outer surfaces, etc.) of various shapes. It is possible to form a solid electrolyte thin film on the entire surface or any part thereof. Also, CV
Compared with D / EVD, plasma spraying, etc., expensive manufacturing equipment is not required, and application to large-sized products is easy.

[Brief description of the drawings]

FIG. 1 is a view showing a relationship between gas permeability coefficients when slurries having different BET18 powder ratios according to Example 1 are used.

FIG. 2 shows BET10 powder and BE according to Example 2.
It is a figure which shows the gas transmission coefficient by the difference of the film thickness ratio at the time of lamination | stacking film formation using the slurry by T18 powder.

FIG. 3 shows BET10 powder and BE according to Example 3.
It is a figure which shows the gas permeation coefficient at the time of multilayer lamination film formation using the slurry by T18 powder.

FIG. 4 shows a BE having a small average specific surface area according to Example 4.
It is a figure which shows the gas permeation coefficient at the time of lamination film formation by the presence or absence of mixing of BET14 powder with T10 powder.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G301 CA02 CA26 CA28 CA30 CD01 5H018 AA06 AS02 AS03 BB01 BB08 EE13 HH08 5H026 AA06 BB01 BB04 BB06 BB08 EE13 HH02 HH03 HH08

Claims (18)

[Claims] 1. A dense solid electrolyte membrane in which a solid electrolyte membrane made of a solid electrolyte powder is formed on an electrode substrate, wherein the solid electrolyte powder contains a plurality of powders having different average specific surface areas (average particle diameters). A dense solid electrolyte membrane characterized by the following. Wherein said solid electrolyte powder, dense solid electrolyte membrane of claim 1 wherein the average specific surface area, characterized in that a plurality arbitrarily selected from 0.2m ² / g~50m ² / powder. 3. The dense solid electrolyte membrane according to claim 1, wherein the difference between the average specific surface areas of the plurality of solid electrolyte powders is 1: 1.5 or more. 4. The mixing ratio of a solid electrolyte powder having a small average specific surface area (hereinafter, “first powder”) among the plurality of solid electrolyte powders is increased.
4. The dense solid electrolyte membrane according to 3. 5. A solid electrolyte membrane comprising: a solid electrolyte membrane comprising the first powder; and a solid electrolyte powder having an average specific surface area larger than the first powder (hereinafter, “second powder”). The dense solid electrolyte membrane according to any one of claims 1 to 3, wherein the dense solid electrolyte membrane is formed by laminating an electrolyte membrane and a layer. 6. The dense material according to claim 5, wherein the thickness of the solid electrolyte membrane made of the first powder is larger than the thickness of the solid electrolyte membrane made of the second powder. Solid electrolyte membrane. 7. A solid electrolyte membrane comprising a first powder formed on an electrode substrate, and a solid electrolyte membrane comprising a second powder formed on the solid electrolyte membrane. 7. The dense solid electrolyte membrane according to 5 or 6. 8. The dense solid electrolyte membrane according to claim 1, wherein a zirconia (ZrO ₂ ) or ceria (CeO ₂ ) is used as the solid electrolyte powder. 9. The solid electrolyte membrane having a thickness of 5 to 150
The dense solid electrolyte membrane according to claim 1, wherein the thickness is set to μm. 10. A solid oxide fuel cell comprising the dense solid electrolyte membrane according to claim 1. 11. A method for producing a dense solid electrolyte membrane, comprising: preparing a slurry containing first and second powders; and forming the slurry on an electrode substrate. 12. The method for producing a dense solid electrolyte membrane according to claim 11, wherein the slurry containing the first and second powders is layered on an electrode substrate to form a film. 13. The method for producing a dense solid electrolyte membrane according to claim 12, wherein a slurry comprising the first powder is first formed on the electrode substrate. 14. The method for producing a dense solid electrolyte membrane according to claim 11, wherein slurries containing the first and second powders are separately prepared, and then the plurality of slurries are mixed. 15. The solid electrolyte powder is pulverized and mixed with a ceramic ball.
The method for producing a dense solid electrolyte membrane according to the above. 16. The sintering temperature of the solid electrolyte membrane is set to 120.
The temperature is set to 0 ° C to 1700 ° C.
16. The method for producing a dense solid electrolyte membrane according to 15. 17. A slurry containing a composite powder (LSCM / YSZ) of La (Sr, Ca) MnO ₃ perovskite oxide (LSCM) and yttria-doped zirconia (YSZ) is formed on an air electrode base, A method for producing a dense solid electrolyte membrane, comprising forming a slurry containing the first and second powders on the membrane on the cathode base. 18. A method according to claim 11, wherein a dense solid electrolyte membrane is formed on the cathode base, and a fuel electrode is formed on the dense solid electrolyte membrane. Of manufacturing a solid oxide fuel cell.