JPH081807B2 - Electrolyte substrate, method for manufacturing the same, and fuel cell using the electrolyte substrate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolyte substrate for a molten carbonate fuel cell, a method for producing the same, and a fuel cell using the electrolyte substrate.

[0002]

2. Description of the Related Art A molten carbonate fuel cell uses a mixed carbonate such as lithium carbonate and potassium carbonate as an electrolyte.
Operate at a temperature near ℃. The mixed carbonate melts at the operating temperature into a liquid with low viscosity. Therefore, the fuel cell is configured by using the electrolyte plate holding the above electrolyte as the electrolyte holding material.

The electrolyte holding material is used by molding a lithium aluminate (LiAlO ₂ ) powder, which is the most stable in molten carbonate, as a raw material into a paper electrolyte substrate. A doctor blade method is generally adopted as a method for molding lithium aluminate, and a mixed solvent such as trichloroethylene, tetrachloroethylene, and trichloroethane is added to lithium aluminate powder and kneaded to form a slurry.

[0004]

The inventors of the present invention have prepared an electrolyte holding substrate by using lithium aluminate powder as a raw material, tetrachloroethylene and trichlorethylene as a solvent, and polyvinyl butyral as a binder. However, it has been found that there is a difference in the pore distribution and porosity of the substrate due to the difference in the lot of raw materials, the difference in manufacturing date, and the difference in storage days.

Various investigations have been made into the cause of the problem. Since the surface of the lithium aluminate powder is hydrophilic, it gradually absorbs moisture during storage and transportation to deteriorate, and particles of the lithium aluminate powder agglomerate. It has been found that the physical properties change remarkably, which is an obstacle to the production of the electrolyte substrate, especially in controlling the pores of the electrolyte substrate. In addition, it is expected that the use of conventionally used chlorine-based organic solvents such as trichloroethylene, tetrachloroethylene, and trichloroethane will be severely restricted from the viewpoint of global environmental problems.

Therefore, in order to develop a molten carbonate fuel cell, it is necessary to establish a method for manufacturing an electrolyte substrate using a solvent other than a chlorine-based organic solvent. Since a general non-chlorine-based organic solvent is easily ignited and may cause an explosion, it is desirable to use an aqueous solvent. Therefore, when an electrolyte substrate was prepared using an aqueous solvent as a solvent for dispersing the lithium aluminate powder, the pH increased to 12 or more in the process of preparing the slurry, and the slurry viscosity gradually increased with continued kneading. Eventually, it solidified into cement and could not be made into plates. It was found that these causes were caused by the hydrolysis and hydration of lithium aluminate.

When the hydration reaction occurs, the slurry viscosity becomes high and the moldability deteriorates. Further, not only does it take a long time to dry, but the crystal phase changes, which causes cracks.
Conventionally, in an electrolyte plate produced by adding an alkali metal carbonate electrolyte using lithium aluminate as a holding material, no consideration has been given to alteration of lithium aluminate powder or change of physical properties due to moisture absorption. For example, JP-A-59-217956 and JP-A-61-193347.
Japanese Patent Application Laid-Open No. 60-72172, Japanese Patent Application Laid-Open No. 60-81772 and Japanese Patent Application Laid-Open No. 1-72172 propose a method of molding a mixed slurry of lithium aluminate, ethanol, polyvinyl butyral and the like into a sheet. 2065
Japanese Patent Publication No. 68 proposes a molding method using an aqueous papermaking method, but does not disclose measures against alteration of the lithium aluminate powder.

The present invention facilitates quality control of a fuel cell electrolyte plate comprising lithium aluminate as an electrolyte holding material and an alkali metal carbonate electrolyte added to the electrolyte holding material to economically produce a highly reliable electrolyte plate. The purpose is to provide a way to. Another object of the present invention is to further improve the reliability of the fuel cell by easily and high quality producing an electrolyte holding substrate of a molten carbonate fuel cell using lithium aluminate as an electrolyte holding material in an aqueous solution system. To do.

[0009]

In order to achieve the above object, in the present invention, a surface stabilizing layer is formed on a lithium aluminum powder. It is most effective that the surface stabilizing layer is made hydrophobic. As a result, it is possible to prevent deterioration of the lithium aluminate during storage or transportation and to produce a high quality electrolyte plate. Further, the hydrolysis and hydration reaction in the aqueous solvent are suppressed, the fluidity of the slurry is improved, and the molding of the electrolyte substrate is facilitated. By forming the first layer to be hydrophobic and forming the hydrophilic second layer on the surface stabilizing layer, the dispersibility of lithium aluminate in the slurry is improved. Especially, the effect becomes remarkable in the aqueous solution type slurry.

The surface stabilizing layer is formed by coating the surface of the lithium aluminate powder with a hydrophobic material having a contact angle with water of 80 degrees or more. For example, one coated with an epoxy resin, a phenol resin, an acrylic resin and a fluororesin, a methacrylic acid / acrylic acid copolymer, and / or a composite of two or more kinds thereof, or a paraffin oil, a naphthene oil. And those modified with hydrophobicity by coating with grease oil or the like, and those coated with a hydrophobic agent such as kerosene or stearic acid. Further, it is also effective to form a protective film on the surface of the lithium aluminate powder with various coupling agents, and if a protective film is formed and further coated with the above resin and / or various oils and fats, a stronger surface stabilizing layer is obtained. Are preferably formed.

Further, a water-repellent layer can be formed by utilizing surface functional groups of lithium aluminate and treating the surface with alcohols at high temperature and high pressure to esterify the surface. As alcohols, ethanol, butanol and the like are preferable. It is also recognized that esterified fatty acids are effective. However, if the surface of the lithium aluminate is modified to be hydrophobic, the dispersibility of the aqueous slurry may decrease. In such a case, the dispersibility is improved by adding a hydrophilic layer to the hydrophobic layer. As the hydrophilizing agent, water-soluble polymer agents such as methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyethylene oxide, polyethylene glycol and the like are suitable. Also,
Dispersibility is also improved by adding a surfactant to the slurry. That is, the object is achieved by further covering the lithium aluminate powder coated with a hydrophobic material with a hydrophilic material having a contact angle with water of 70 degrees or less.

In the method of adding a solvent, a binder and the like to the lithium aluminate powder having the surface stabilizing layer and mixing them to prepare a slurry and molding into a sheet, the solvent is water or an organic solvent such as isobutyl alcohol. One or two or more kinds of mixed solvents selected from isopropyl alcohol, cyclohexanol, 1-butanol, 2-butanol, toluene, methanol, trichloroethylene, trichloroethane and the like can be applied. As the binder, one or two or more mixed binders such as carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyethylene oxide, polyvinyl butyral and polyvinyl acetal can be applied. Further, if a small amount of glycerin, phthalic acid ester, dipropyl glycol or the like is added as a plasticizer, the moldability is improved.

In the step of adding a solvent and a binder to the lithium aluminate powder on which the surface stabilizing layer is formed and kneading to prepare a slurry, the temperature is 80 ° C. or lower, preferably 50 ° C.
It is good to knead at the following temperature. In the temperature range of 80 ° C. or higher, the surface stabilizing layer may be destroyed and the lithium aluminate may be deteriorated. Bubbles in the slurry must be degassed by depressurizing them with a vacuum pump or the like. The raw material slurry degassed under reduced pressure is formed into a sheet having a thickness of about 0.2 to 1 mm by a tape casting method, a slit forming method, or the like and dried to obtain an electrolyte substrate.

[0014]

[Function] By forming a surface stabilizing layer on the lithium aluminate powder, deterioration of the lithium aluminate during storage or transportation and secondary aggregation are prevented, the quality control of the powder is facilitated, and the pore distribution of the electrolyte substrate and the A highly reliable fuel cell can be constructed by reducing fluctuations in porosity. Further, it suppresses the hydrolysis and hydration reaction of lithium aluminate in the aqueous solution system, improves the fluidity of the slurry, and facilitates the production of the electrolyte substrate.

[0015]

EXAMPLES The present invention will be described in more detail by way of examples. Example 1. γ-Lithium aluminate powder (specific surface area:
The epoxy resin (10 g) and acetone (60 ml) were added to 100 m (23 m ² / g), and the mixture was kneaded with a kneader for 3 hours and then vacuum dried to form a hydrophobic layer on the surface of the lithium aluminate powder. Embodiment 2. FIG. γ-Lithium aluminate powder (specific surface area:
23 m ² / g) 100 g was dispersed in 200 ml of xylene and placed in a flask with a reflux tube, methyl methacrylate, 10 g of vinyl acetate and 2 g of azobisisobutyronitrile were added and stirred for 3 hours while heating at about 70 ° C., After standing for about 5 hours to separate the supernatant liquid, vacuum drying is performed to coat the surface of lithium aluminate with an acrylic acid copolymer,
A hydrophobic layer was formed on the surface of the lithium aluminate powder. Example 3. γ-Lithium aluminate powder (specific surface area:
23m ² / g) 150g and n-butanol 50ml were added and heated in an autoclave to 280 ° C, 50kg.
A pressure of / cm ² was maintained for 30 minutes. As a result, the surface of the lithium aluminate was esterified to form a hydrophobic layer. Example 4. γ-Lithium aluminate powder (specific surface area:
23 m ² / g) 1 wt% in 100 g 1.1.1.1.
3.3-Hexafluoro-2-propanol 300 ml
Was added, and the mixture was stirred for about 3 hours, and allowed to stand for about 5 hours to separate the supernatant, followed by vacuum drying to form a hydrophobic layer on the surface of lithium aluminate. Example 5. γ-Lithium aluminate powder (specific surface area:
Stearic acid (10 g) was added to 100 g (23 m ² / g) and mixed by a vibration mill for 3 hours, and then heat-treated at 80 ° C. for about 4 hours to form a hydrophobic layer on the surface of lithium aluminate. Example 6. γ-Lithium aluminate powder (specific surface area:
60 ml of naphthenic mineral oil (Sunsen oil # 480) was added to 100 g of 23 m ² / g) and kneaded with a kneader for 3 hours to form a hydrophobic layer on the surface of lithium aluminate. Comparative Example 1. The γ-lithium aluminate powder (specific surface area: 23 m ² / g) used in Examples 1 to 6 was used as it was without treatment. Experimental Example 1 With respect to the powder having a hydrophobic layer formed on the surface of the lithium aluminate produced in Examples 1 to 6 and the lithium aluminate powder of Comparative Example 1, the immersion heat amount was measured to examine the stability in an aqueous solution. The sample was dried at 120 ° C. for 3 hours and then degassed under vacuum at 10 ⁻³ Torr to obtain a test sample. The results of measurement of the amount of heat of immersion are shown in Table 1.

The amounts of heat of immersion of the samples of the above Examples are smaller than those of the samples of Comparative Example 1, and it is recognized that the hydration reaction and the like are suppressed.

[0017]

[Table 1]

Experimental Example 2 The pH of the lithium aluminate powder having the hydrophobic layer formed in Examples 1 to 6 and the lithium aluminate powder of Comparative Example 1 was measured in order to understand the stability in an aqueous solution. Pour 20g of powder sample into 200ml of distilled water 1
After stirring for an hour, the pH was measured. The measurement results are shown in Table 2.

The samples of Examples 1 to 6 have lower pH values than the sample of Comparative Example 1, suggesting that the hydrolysis reaction of lithium aluminate is suppressed.

[0020]

[Table 2]

Examples 7 to 12 5 ml of polyethylene glycol was added to 20 g of each of the six kinds of lithium aluminate powder having a hydrophobic layer formed on the surface prepared in Examples 1 to 6 and kneaded with a kneader for about 2 hours. Six kinds of samples were prepared by further forming a hydrophilic layer on the surface of the hydrophobic layer of the lithium aluminate powders 1 to 6. Lithium aluminate powder 2 of each of these samples and Comparative Example 1
50 ml of a 3 wt% polyethylene oxide aqueous solution was added to each of 0 g and kneaded with a ball mill for 24 hours to prepare a slurry, and the viscosity at that time was measured. The measurement results are shown in Table 3.

The samples of Examples 7 to 12 have lower viscosities than the sample of Comparative Example 1, and it can be seen that there is no problem in making a plate.

[0023]

[Table 3]

Example 13 To 100 g of γ-lithium aluminate powder (specific surface area: 23 m ² / g), 10 g of epoxy resin and 60 ml of acetone were added and kneaded with a kneader for 3 hours, followed by vacuum drying to form a hydrophobic layer on the surface of lithium aluminate. . Next, 10 ml of polyethylene glycol was added and kneaded with a kneader for about 2 hours to form a hydrophilic layer on the surface of the hydrophobic layer. Distilled water 1
X-ray analysis was carried out after adding 00 ml and kneading with a ball mill for 15 hours and then drying at 120 ° C. for 5 hours. The measurement results are shown in FIG. The measurement result in FIG. 1 shows that the crystal phase of lithium aluminate is γ-LiAlO ₂ as in the starting material.
It means that it did not deteriorate. Comparative example 2. γ-Lithium aluminate powder (specific surface area:
23 m ² / g) and 20 ml of distilled water and 100 ml of distilled water, and the mixture was kneaded in a ball mill for 15 hours in the same manner as in Example 13, and then 12
After drying at 0 ° C. for 5 hours, X-ray analysis was performed. The measurement results are shown in FIG. The measurement results in Fig. 2 show that the crystal phase of lithium aluminate differs from the starting material in LiAlO ₂ (OH)
It is shown that it has been transformed into ₇ · xH ₂ O. Example 14. 100 g of γ-lithium aluminate powder (specific surface area: 23 m ² / g) was dispersed in 200 ml of xylene and placed in a flask equipped with a reflux tube.
Vinyl acetate 10g and azobisisobutyronitrile 2g
Was added, and the mixture was stirred for 3 hours while heating to about 70 ° C., cooled, and allowed to stand for about 5 hours to separate a supernatant liquid, followed by vacuum drying to coat the surface of lithium aluminate with an acrylic acid copolymer. , A hydrophobic layer was formed.

To this, 30 g of polyvinyl butyral, 94 ml of methanol, 142 ml of n-butanol and 10 ml of butyl phenylphenol glycolate were added and kneaded in a ball mill for 15 hours at room temperature to prepare a slurry. The slurry was deaerated under reduced pressure with a vacuum pump and then formed into a plate having a thickness of 0.4 mm and a width of 200 mm by a tape casting method to prepare an electrolyte substrate. This electrolyte substrate was stored in the air at room temperature, and one day after the start of storage and 90 days after the start of storage were fired at 650 ° C. for 3 hours, and then the pore distribution was measured by the mercury porosimetry. FIG. 3 shows the results. FIG. 3 shows that the pore distribution after 1 day and after 90 days hardly changes. Comparative Example 3 γ-Lithium aluminate powder (specific surface area: 23 m ² /
g) 100 g in the same manner as in Example 14: 30 g of polyvinyl butyral, 94 ml of methanol, 142 ml of n-butanol and 1 butyl butylphenol glycolate.
0 ml was added and kneaded with a ball mill for 15 hours at room temperature to prepare a slurry. The slurry was deaerated under reduced pressure with a vacuum pump and then formed into a plate having a thickness of 0.4 mm and a width of 200 mm by a tape casting method to prepare an electrolyte substrate. This electrolyte substrate was stored in air at room temperature for 1 day and 9 days after the start of storage.
After baking the ones after 0 days at 650 ° C for 3 hours respectively,
The pore size distribution was measured by mercury porosimetry. The results are shown in FIG. FIG. 4 shows that the pore distribution changed significantly after 1 and 90 days. Example 15. The electrolyte substrate prepared in Example 14 (cell N
o. 1) and the electrolyte substrate prepared in Comparative Example 3 (cell N
o. Two pieces of 2) were cut into 120 mm square pieces, and a carbonate electrolyte (K ₂ CO ₃ : Li ₂ CO ₃ = 38: 62) 21
g was sandwiched between electrolyte substrates, a Ni-Al electrode was applied to the anode, a NiO-Ag electrode was used as a cathode, and a single cell having an electrode effective area of 100 cm ² was constructed. These unit cells were set in a battery tester, a tightening load of 4 kg / cm ² was applied, and 18% CO ² was applied to the anode.
₂ -16% H ₂ O- remainder H ₂ mixed gas supply, cathode - while supplying 70% air -30% CO ₂ gas mixture to de 5
The temperature was raised to 20 ° C. to impregnate the electrolyte substrate with the carbonate electrolyte to form an electrolyte plate inside the cell.

Further, the temperature was raised to 650 ° C. and the change with time of the battery voltage at a load current density of 150 mA / cm ² was examined. The test results are shown in Table 4. It can be seen that the cell of Example 15 (cell No. 1) has more stable performance than the cell of Comparative Example (cell No. 2).

[0027]

[Table 4]

Example 16 To 100 g of γ-lithium aluminate powder (specific surface area: 23 m ² / g), 10 g of epoxy resin and 60 ml of acetone were added and kneaded with a kneader for 3 hours, followed by vacuum drying to form a hydrophobic layer on the surface of lithium aluminate. . Next, 10 ml of polyethylene glycol was added and kneaded with a kneader for about 2 hours to form a hydrophilic layer on the surface of the hydrophobic layer.

To the lithium aluminate powder thus obtained, 200 ml of a 2.0 wt% polyethylene oxide aqueous solution and 10 ml of glycerin were added and kneaded in a ball mill for 15 hours to prepare a slurry. The slurry was deaerated under reduced pressure with a vacuum pump and then formed into a plate having a thickness of 0.4 mm and a width of 200 mm by a tape casting method to prepare an electrolyte substrate.

Two pieces of this electrolyte substrate were cut into 120 mm square pieces, and a carbonate electrolyte (K ₂ CO ₃ : Li ₂ CO ₃ = 38:
62) 21 g of Ni is sandwiched between electrolyte substrates
-The Al electrode is applied to the anode, and the cathode is made of NiO.
A single cell having an electrode effective area of 100 cm ² was constructed by using an Ag electrode. This unit cell was set in the battery tester and a tightening load of 4 kg / cm ² was applied, and 18% was applied to the anode.
CO ₂ -16% H ₂ O-remaining H ₂ mixed gas is supplied, and while 70% air-30% CO ₂ mixed gas is supplied to the cathode, the temperature is raised to 520 ° C. and the carbonate electrolyte is applied to the electrolyte substrate. An electrolyte plate was formed inside the cell by impregnation. Comparative Example 4. γ-Lithium aluminate powder (specific surface area:
23m ² / g) 100g, 2.0 wt% polyethylene oxide aqueous solution 200ml, distilled water 80ml and glycerin 10ml were added and kneaded with a ball mill for 15 hours to prepare a slurry. The slurry was deaerated under reduced pressure with a vacuum pump and then formed into a plate having a thickness of 0.4 mm and a width of 200 mm by a tape casting method to prepare an electrolyte substrate.

Two pieces of this electrolyte substrate were cut into 120 mm square pieces, and a carbonate electrolyte (K ₂ CO ₃ : Li ₂ CO ₃ = 38:
62) 21 g of Ni is sandwiched between electrolyte substrates
-The Al electrode is applied to the anode, and the cathode is made of NiO.
A single cell having an electrode effective area of 100 cm ² was constructed by using an Ag electrode. This unit cell was set in the battery tester and a tightening load of 4 kg / cm ² was applied to the anode of 18% C.
O ₂ -16% H ₂ O-remaining H ₂ mixed gas was supplied, and
While supplying 70% air-30% CO ₂ mixed gas to the cathode, the temperature was raised to 520 ° C. to impregnate the electrolyte substrate with the carbonate electrolyte to form an electrolyte plate inside the cell.

The electrolyte plate of Example 16 and the electrolyte plate of Comparative Example 4 were further heated to 650 ° C. and the load current density 1
The change with time of the battery voltage at 50 mA / cm ² was examined. The test results are shown in Table 5. It can be seen that the cell using the electrolyte plate of Example 16 has more stable performance than the cell using the electrolyte plate of Comparative Example 4.

[0033]

[Table 5]

[0034]

According to the present invention, by forming the surface stabilizing layer on the lithium aluminate powder, it is possible to prevent alteration of the lithium aluminate during storage or transportation and to produce a high quality electrolyte substrate plate. The reliability of the fuel cell can be improved. Furthermore, according to the present invention, by forming the surface stabilizing layer on the lithium aluminate powder, it is possible to suppress the hydration reaction or hydrolysis reaction of the lithium aluminate in the aqueous solution system. As a solvent for dispersion, an aqueous solvent can be used in place of the conventional chlorine organic solvent, and the problem of environmental pollution can be sufficiently addressed and the safety of work can be secured.

[Brief description of drawings]

FIG. 1 is a view showing an X-ray diffraction result of an aqueous slurry (dry product) of lithium aluminate powder having a surface stabilizing layer formed of an epoxy resin.

FIG. 2 is a view showing an X-ray diffraction result of an aqueous solution slurry (dry product) of untreated lithium aluminate powder.

FIG. 3 is a diagram showing changes over time in the pore distribution of an electrolyte substrate using lithium aluminate having a surface stabilizing layer formed of an acrylic acid copolymer.

FIG. 4 is a diagram showing changes over time in the pore distribution of an electrolyte substrate using untreated lithium aluminate powder.

[Explanation of symbols]

1 Diffraction line of γ-LiAlO ₂ 2 LiAlO ₂ (OH) ₇ · xH ₂ O diffraction line 3 Pore distribution after 1 day 4 Pore distribution after 90 days

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Iwamoto 1-7-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Yoshio Iwase 7-chome, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 Incorporated company Hitachi Ltd. in Hitachi Research Laboratory (72) Inventor Masato Takeuchi 7-11 Omika-cho, Hitachi City, Ibaraki Prefecture Incorporated Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Shigeo Nishimura Hitachi, Ibaraki Prefecture 7-1 Mika-cho, Oita-shi, Ltd. Hitachi, Ltd., Hitachi Research Laboratory (56) References Japanese Patent Laid-Open No. 61-24165 (JP, A)

Claims (15)

[Claims] 1. A lithium aluminate as an electrolyte holding material.
In the electrolyte substrate, the lithium aluminate
Was formed of a hydrophobic material having a contact angle with water of 80 degrees or more.
Electrolyte characterized by having a surface stabilizing layer
substrate. Wherein said passivation layer is epoxy resin, phenol resin, according to claim 1, characterized in that the coating layer formed by any and / or mixtures thereof acrylic resin or fluorine resin Electrolyte substrate. 3. The surface stabilizing layer is characterized in that the surface is coated with paraffinic oil, naphthenic oil, grease-like oil or the like and the surface layer is modified to be hydrophobic.
The electrolyte substrate according to claim 1 . 4. A claim that the lithium aluminate surface, characterized in that the hydrophobically modified with a coupling agent
1. The electrolyte substrate according to 1 . 5. The lithium aluminate surface, characterized in that the hydrophobically modified by stearate claim 1
The electrolyte substrate described . 6. The electrolyte substrate according to claim 1 , wherein the surface of the lithium aluminate is modified to be hydrophobic by reacting with a primary alcohol and / or a secondary alcohol to esterify the surface. 7. The electrolyte substrate according to claim 2 , wherein the hydrophobic layer is formed in two layers or in a multilayer of two or more layers. 8. The electrolyte substrate according to claim 1, wherein the surface stabilizing layer has a hydrophilic layer formed on the surface of a hydrophobic layer. 9. claims contact angle with water on the surface of the hydrophobic layer is characterized by forming a hydrophilic layer by 70 degrees or less of the material
8. The electrolyte substrate according to 8 . 10. A hydrophilic layer comprising methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose,
The electrolyte substrate according to claim 8 or 9, which is formed of a water-soluble polymer agent such as polyvinyl alcohol, polyethylene oxide, or polyethylene glycol. 11. The electrolyte substrate according to claim 8 or 9 , wherein the hydrophilic layer is formed by adsorption of a surfactant. 12. A hydrophobic material having a contact angle with water of 80 degrees or more.
Lithium aluminate powder to form a passivation layer by the solvent, and mixed with a binder and a plasticizer to prepare a slurry, characterized by being formed into a sheet according
Item 12. The electrolyte substrate according to any one of items 1 to 11 . 13. An electrolyte plate obtained by adding an alkali metal carbonate electrolyte to the electrolyte substrate according to any one of claims 1 to 12. 14. A fuel cell using the electrolyte plate according to claim 13 . 15. A hydrophobic material having a contact angle with water of 80 degrees or more.
Lithium aluminate powder to form a passivation layer by the solvent, a slurry was prepared by mixing by adding a binder and a plasticizer, characterized in that formed into a sheet according
Item 12. A method for producing the electrolyte substrate according to any one of Items 1 to 11 .