JP6199680B2 - Solid oxide fuel cell half cell and solid oxide fuel cell - Google Patents

Description

  The present invention relates to a half cell of a solid oxide fuel cell and a solid oxide fuel cell.

  In recent years, fuel cells have attracted attention as clean energy sources. Among fuel cells, solid oxide fuel cells that use solid ceramics as the electrolyte (hereinafter sometimes referred to as “SOFC”) can use exhaust heat because of their high operating temperature, and are even more efficient. It has the advantage of being able to obtain electric power, and is expected to be used in a wide range of fields from household power sources to large-scale power generation.

  The SOFC has a structure in which a solid electrolyte layer made of ceramics is disposed between a cathode (air electrode) and an anode (fuel electrode) as a basic structure. For example, in a flat SOFC, a single cell is formed by superposing a cathode, a solid electrolyte layer, and an anode, and a plurality of the single cells are stacked with an interconnector interposed therebetween to obtain high output. Such a flat SOFC includes an electrolyte support cell (ESC) that maintains the strength of the cell with an electrolyte as a support, an anode support cell (ASC) that maintains the strength of the cell with an anode as a support, and a cathode. There is a cathode support cell (CSC) as a support.

For example, nickel-zirconia cermet (sintered body) is generally used as the anode of the SOFC. Each time the SOFC is used, the fuel electrode is exposed to a high-temperature atmosphere, so that nickel in the fuel electrode aggregates and the conductivity of the fuel electrode decreases, so the problem is that the power generation performance of the SOFC decreases. . In order to solve such problems, Patent Document 1 proposes a material containing a metal oxide additive such as aluminum oxide (Al ₂ O ₃ ) as a fuel electrode material of a solid oxide fuel cell (patent). Reference 1).

  Patent Document 2 proposes an SOFC cell that employs a skeleton structure made of a Ni—Mn alloy or a Ni—Mo alloy instead of Ni as the skeleton structure of the anode. In this SOFC cell, the agglomeration of the skeletal structure alloy is suppressed, and the cell voltage drop rate is small even when operated for a long time.

JP 2011-198758 A JP 2010-232135 A

  By the way, regarding the power generation performance of the SOFC, there is a problem that the output voltage may decrease in the initial operation.

  Accordingly, an object of the present invention is to provide a SOFC half cell and a SOFC cell capable of suppressing a decrease in output voltage in the initial operation of the SOFC.

The present invention
A half cell of a solid oxide fuel cell,
An anode including a conductive component and an electrolyte component;
An electrolyte layer formed on one main surface of the anode,
The half cell is left in an electric furnace at a temperature of 750 ° C. in a mixed gas atmosphere with a volume ratio of H ₂ and N ₂ of 1: 9 and a pressure of 1 atm, and then the electrolyte of the conductive component Provided is a half-cell having a peeling degree of 10% or less with respect to components.

  The present invention also provides a solid oxide fuel cell in which the cathode is formed in the above half cell.

  In the half cell of the present invention, the degree of peeling of the conductive component with respect to the electrolyte component after reducing the anode under predetermined conditions is 10% or less. For this reason, even if the conductive component of the anode is reduced and contracted by hydrogen as a fuel, the degree of separation from the electrolyte component is kept low. Thereby, it is possible to suppress a decrease in the three-phase interface between the conductive component, the electrolyte component, and the gas phase, and it is possible to suppress a decrease in output voltage in the initial operation of the SOFC.

Sectional drawing which shows one Embodiment of half cell of SOFC Sectional drawing which shows one Embodiment of SOFC cell SEM photograph of cross section of anode active layer according to Example 3 after hydrogen reduction treatment SEM photograph of cross section of anode active layer according to Comparative Example 5 after hydrogen reduction treatment

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description relates to an example of the present invention, and the present invention is not limited to these.

  As shown in FIG. 1A, the half cell 1 includes an anode 10, an electrolyte layer 20 formed on one main surface of the anode 10, and a barrier layer formed on the surface of the electrolyte layer 20 opposite to the surface in contact with the anode 10. 30. FIG. 1B shows the SOFC cell 2 in which the cathode 40 is formed in the half cell 1.

  The anode 10 includes an anode active layer 11 and an anode support substrate 12. The anode active layer 11 includes a conductive component and an electrolyte component as main components, and is a layer in which an electrochemical reaction is substantially performed. The electrolyte component can also be referred to as a skeleton component made of a ceramic material. The anode support substrate 12 includes a conductive component and an electrolyte component as main components, guides a fuel gas such as hydrogen to the anode active layer 11, supports the electrolyte layer 20 and the cathode 10, and the half cell 1 or the SOFC cell 2 as a whole. It functions as a support. That is, the half cell of this embodiment is an anode supported cell (ASC) half cell. The electrolyte component contained in the anode support substrate 12 is also a skeleton component made of a ceramic material. When the anode support substrate 12 functions sufficiently as an anode, the anode active layer 11 may be omitted.

  The anode 10 (the anode active layer 11 or the anode support substrate 12) is configured as a fired body of a mixture containing a conductive component powder and an electrolyte component powder. In this mixture, the conductive component powder and the electrolyte component powder are calcined at 800 to 1050 ° C. for 0.2 to 3 hours. Thereby, the peeling degree mentioned later shows a low value.

  When the half cell 1 of this embodiment is subjected to hydrogen reduction treatment under a predetermined condition and observed with a scanning electron microscope (SEM) and the degree of peeling is determined as follows, the anode active layer 11 of the half cell 1 of this embodiment is determined. The degree of peeling of the conductive component with respect to the electrolyte component is 10% or less. The hydrogen reduction treatment of the half cell 1 is performed by allowing the half cell 1 to stand for 4 hours in an electric furnace having a volume ratio of hydrogen to nitrogen of 1: 9 and a pressure of 1 atm and a temperature of 750 ° C. Done.

Also, the degree of exfoliation was measured with a SEM image of a 4.5 μm × 6 μm region obtained by magnifying the cross section of the anode active layer 11 of the half cell 1 after the hydrogen reduction treatment by 20000 times. When the total perimeter of the body (excluding the part in contact with the vacancies) is La, and the total length of the parts of the conductive component granules not in contact with the electrolyte component granules is Lb, It is defined by the formula of
Peel degree [%] = (Lb / La) × 100

  In the anode active layer 11, the SOFC using a half cell in which the degree of exfoliation of the conductive component with respect to the electrolyte component is 10% or less is lower than the SOFC using the half cell in which the degree of exfoliation is greater than 10%. Is suppressed.

  It is considered that the conductive component of the anode active layer 11 may be peeled off from the electrolyte component when the conductive component of the anode active layer 11 is reduced and contracted by hydrogen as a fuel in the initial stage of operation. The separation between the conductive component and the electrolyte component reduces the three-phase interface between the conductive component, the electrolyte component, and the gas phase, and is considered to cause a decrease in power generation performance (output voltage) at the initial stage of operation. In this embodiment, even if the conductive component of the anode active layer 11 is reduced and contracted by hydrogen as a fuel in the initial stage of operation, separation of the conductive component from the electrolyte component is suppressed. The decrease in performance is suppressed.

  The conductive component contained in the anode active layer 11 is a metal oxide that changes into a conductive metal in a reducing atmosphere during fuel cell operation, such as nickel oxide, cobalt oxide, or iron oxide; or two or more of these oxides Examples thereof include composite metal oxides such as nickel ferrite and cobalt ferrite. These may be used alone or in combination of two or more as necessary. Among these, nickel oxide, cobalt oxide, and iron oxide are preferable.

As the electrolyte component contained in the anode active layer 11, zirconia, alumina, magnesia, titania, aluminum nitride, mullite or the like is used alone or in combination. Of these, stabilized zirconia is the most versatile. Examples of the stabilized zirconia include zirconia, oxides of alkaline earth metals such as MgO, CaO, SrO, and BaO; Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Pr ₂ O ₃ , Nd ₂ Oxides of rare earth elements such as O ₃ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₂ O ₃ , Dy ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ ; One in which at least one oxide selected from Sc ₂ O ₃ ; Bi ₂ O ₃ ; and In ₂ O ₃ is dissolved, or further, alumina, titania, Ta ₂ O as a dispersion strengthening agent. Dispersion strengthened zirconia to which ₅ and Nb ₂ O ₅ are added is exemplified as a preferable example. Further, as an electrolyte component, CeO ₂ or Bi ₂ O ₃ , CaO, SrO, BaO, Y ₂ O ₃ , La ₂ O ₃ , Ce ₂ O ₃ , Pr ₂ O ₃ , Nb ₂ O ₃ , Sm ₂ O _{3 are used.} Eu ₂ O ₃ , Gd ₂ O ₃ , Tb ₂ O ₃ , Dr ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Yb ₂ O ₃ , PbO, WO ₃ , MoO ₃ , V ₂ O ₅ , Ta Ceria-based or bismuth-based ceramics to which at least one selected from ₂ O ₅ and Nb ₂ O ₅ is added can also be used. A gallate ceramic such as LaGaO ₃ can also be used. These may be used alone or in combination of two or more. Among these, zirconia stabilized with 3 to 10 mol% yttria and zirconia stabilized with 3 to 10 mol% ytterbia are preferable, and specifically, 3 mol% yttria stabilized zirconia (3YSZ), 8 mol% yttria. Stabilized zirconia (8YSZ), 10 mol% yttria stabilized zirconia (10YSZ), 3 mol% ytterbia stabilized zirconia (3YbSZ), 8 mol% ytterbia stabilized zirconia (8YbSZ) and 10 mol% ytterbia stabilized zirconia (10YbSZ) may be used. preferable.

  As the conductive component and the electrolyte component included in the anode support substrate 12, the same components as those described for the anode active layer 11 can be selected. The conductive component and the electrolyte component included in the anode support substrate 12 may be the same as or different from the conductive component and the electrolyte component included in the anode active layer 11.

  Although the thickness of the anode active layer 11 is not specifically limited, For example, they are 5 micrometers-30 micrometers. Although the thickness is not specifically limited to the anode support substrate 12, For example, they are 150 micrometers-1500 micrometers.

  Since a general SOFC electrolyte layer can be applied to the electrolyte layer 13, the material is not particularly limited. Specifically, the electrolyte layer 13 contains a ceramic material as a main component. The ceramic material is not particularly limited as long as it is normally used as a material for the SOFC electrolyte layer. For example, zirconia stabilized with yttria, ceria, scandia, ytterbia, etc .; doped with yttria, samaria, gadolinia, etc. Lanthanum gallate, lanthanum gallate, and lanthanum gallate perovskite structure oxide in which part of lanthanum or gallium in lanthanum gallate is substituted with strontium, calcium, barium, magnesium, aluminum, indium, cobalt, iron, nickel, copper, etc. Can be used. These may be used alone or in combination of two or more. Among these, zirconia stabilized with yttria, scandia, ytterbia and the like is preferable.

  In particular, as a ceramic material, zirconia stabilized with 3 to 10 mol% yttria, zirconia stabilized with 3 to 12 mol% scandia, zirconia stabilized with 3 to 15 mol% ytterbia, 8 to 12 mol% Preference is given to using zirconia stabilized with scandia and 0.5-5 mol% ceria. A material obtained by adding alumina, silica, titania or the like as a sintering aid or dispersion strengthening agent to these stabilized zirconia can also be suitably used. Among these, for example, 10 mol% scandia 1 mol% ceria stabilized zirconia can be suitably used as the ceramic material.

  Although the thickness of the electrolyte layer 20 is not specifically limited, For example, it is 5-30 micrometers.

  When the cathode 40 is fired in the manufacturing process of the SOFC cell 2 or during the operation of the SOFC, the barrier layer 30 reacts with the electrolyte layer 20 and the cathode 40 to form a high resistance material layer, resulting in a decrease in power generation performance. Play a role to prevent. As a material of the barrier layer, a material mainly containing CeO and a rare earth element can be used. For example, ceria (GDC) doped with gadolinia, ceria (SDC) doped with samaria can be used. Although the thickness of the barrier layer 30 is not specifically limited, For example, it is 1-20 micrometers. Further, the barrier layer 30 is not an essential component and may be omitted depending on the combination of the electrolyte 20 and the cathode 40.

As a material of the cathode 40, for example, a metal, a metal oxide, a metal composite oxide, or the like can be used. Among these, examples of the metal include metals such as Pt, Au, Ag, Pd, Ir, Ru, Ru, and alloys containing two or more metals. In addition, examples of metal oxides include oxides such as La, Sr, Ce, Co, Mn, and Fe (for example, La ₂ O ₃ , SrO, Ce ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , FeO, and the like). Can be mentioned. Examples of the metal complex oxide include various complex oxides containing at least one of La, Pr, Sm, Sr, Ba, Co, Fe, Mn, and the like (for example, La _1-x Sr _x CoO ₃ type composite oxide, La _1-x Sr _x FeO ₃ type composite oxide, La _1-x Sr _x Co _1-y Fe _y O ₃ type composite oxide, La _1-x Sr _x MnO ₃ type composite oxide Pr _1-x Ba _x CoO ₃ composite oxide, Sm _1-x Sr _x CoO ₃ composite oxide, and the like. Here, 0 <x <1, 0 <y <1. Among these, as a material of the cathode 40, a La _1-x Sr _x Co _1-y Fe _y O ₃ composite oxide (hereinafter sometimes referred to as “LSCF”) is preferably used. In this case, the cathode 40 may contain GDC or SDC in order to suppress separation from the barrier layer 30 due to thermal expansion and to improve the ionic conductivity of oxide ions.

  Next, a method for manufacturing the half cell 1 and the SOFC cell 2 of the present embodiment will be described. The anode support substrate 12, the anode active layer 11, the electrolyte layer 20, the barrier layer 30 and the cathode 40 are respectively added with a binder and a solvent to the raw material powder constituting them, and further, if necessary, a dispersant, a plasticizer A slurry or paste is prepared by adding a lubricant, an antifoaming agent, and the like, and the slurry or paste is dried to form a green sheet or a green layer, which is then fired. As the binder and solvent of the slurry or paste prepared for producing the anode support substrate 12, the anode active layer 11, the electrolyte layer 20, the barrier layer 30, and the cathode 40, the binder and solvent become known in the conventional manufacturing method. Can be selected as appropriate.

  In ASC, the anode 10 is first prepared. The anode support substrate 12 is added with a powder of a material constituting a conductive component, a powder of a material constituting an electrolyte component, a binder and a solvent, and further, as necessary, a pore forming agent, a dispersant, a plasticizer, a lubrication A slurry is prepared by adding an agent, an antifoaming agent, and the like, and the slurry is formed into a sheet and then dried to prepare a green sheet for the anode support substrate 12.

  Subsequently, a conductive component, an electrolyte component, a binder and a solvent constituting the anode active layer 11 are added to one main surface of the green sheet for the anode support substrate 12, and a pore forming agent and a dispersing agent are added as necessary. Then, the anode active layer paste prepared by adding a plasticizer, a lubricant, an antifoaming agent and the like is applied at a predetermined thickness, and the coating film is dried to form a green layer for the anode active layer 11. .

  The paste for the anode active layer 11 includes a powder material of a conductive component and a powder material of an electrolyte component constituting the anode active layer 11, and a mixture to which a binder, a solvent and the like are added is crushed and kneaded under predetermined conditions. Can be obtained. As the powder raw material for the conductive component and the powder raw material for the electrolyte component used for the crushing / kneading, those calcined are used. Thereby, it is thought that the above-mentioned peeling degree in the anode active layer 11 of the half cell 1 of this embodiment shows a low value. The temperature of the calcination of the conductive material powder raw material and the electrolyte component powder raw material is, for example, 800 to 1050 ° C., preferably 850 to 1000 ° C., and more preferably 900 to 950 ° C. The calcining time is, for example, 0.2 to 3 hours, preferably 0.5 to 2 hours, and more preferably 1 to 1.5 hours. The calcining of the powder material of the conductive component and the powder material of the electrolyte component may be performed by calcining a mixture of the powder material of the conductive component and the powder material of the electrolyte component. Also, the calcination of the conductive material powder material and the calcination of the electrolyte component powder material may be performed separately.

  Subsequently, a paste for the electrolyte layer 20 is applied at a predetermined thickness on the green layer for the anode active layer 11, and the coating layer is dried to form a green layer for the electrolyte layer 20. Moreover, the green layer for barrier layers 20 is formed by apply | coating the paste for barrier layers 30 by predetermined thickness on the green layer for electrolyte layers 20, and drying the coating film.

  Subsequently, by firing the green sheet of the anode support substrate 12 on which the green layer of the anode active layer 11, the green layer of the electrolyte layer 20, and the green layer of the barrier layer 30 are formed, the half cell 1 of this embodiment is obtained. .

  A paste for the cathode 40 is applied on the barrier layer 30 of the half cell 1 obtained as described above, and this coating film is dried to form a green layer for the cathode 40. Then, the SOFC cell 2 of this embodiment is obtained by baking the half cell in which the green layer for cathodes 40 was formed.

  Although ASC has been described in the above embodiment, the present invention can also be implemented as an electrolyte-supported cell (ESC). In this case, the ESC half cell and the ESC type SOFC cell may be manufactured by the following method, for example. First, an electrolyte slurry is prepared with a ball mill or the like. An electrolyte green sheet is prepared by coating and drying the electrolyte slurry by a doctor blade method. Next, the electrolyte green sheet is fired at a predetermined temperature to obtain an electrolyte sheet. Thereafter, an anode paste is applied to one main surface of the electrolyte sheet, and the coating film is dried to form an anode green layer. Further, if necessary, a barrier layer paste is applied to the other main surface of the electrolyte layer green sheet, and this coating film is dried to form a barrier layer green layer. An ESC half-cell can be obtained by firing an electrolyte sheet on which a green layer for an anode and a green layer for a barrier layer are formed. Moreover, an ESC type SOFC cell is obtained by applying a paste for cathode on the barrier layer of this ESC half-cell, drying this coating film to form a green layer for cathode, and firing it. Can do.

  Next, the present invention will be described in detail by way of examples. In addition, this invention is not limited to a following example.

<Measurement method of degree of peeling>
First, evaluation methods of Examples and Comparative Examples will be described. The degree of exfoliation was measured by observing a cross section along the stacking direction of the anode support substrate, the anode active layer, the electrolyte layer, and the barrier layer of the half cell after the hydrogen reduction treatment described below with an SEM. In the hydrogen reduction treatment, the inside of an electric furnace (manufactured by Koyo Thermo Systems Co., Ltd., KTF045N) having a half cell in a mixed gas atmosphere with a volume ratio of H ₂ and N ₂ of 1: 9 and a pressure of 1 atm and a temperature of 750 ° C. For 4 hours.

A cross section of the half cell subjected to hydrogen reduction treatment was photographed with a SEM at a magnification of 20,000 times. In the photographed image, attention was paid to particles of the conductive component found in the anode active layer, and image analysis was performed using image analysis software (Image-Pro, manufactured by Media Cybernetics). First, the total sum La of the circumferences of the conductive component grains in the seven anode active layers arbitrarily selected in the photographed image was obtained. Here, the length of the portion in contact with the pores was excluded from the peripheral length of the particles of the conductive component. Next, among the circumferences of the seven conductive component granules, the total length Lb of the portions not in contact with the electrolyte component granules was determined. And the peeling degree with respect to the electrolyte component of a conductive component was computed with the following formula | equation.
Peeling degree = (Lb / La) × 100

<Evaluation of initial power generation performance>
The initial power generation performance was evaluated as follows for the SOFC cells according to the examples and the comparative examples. First, the temperature of the SOFC cell was raised to 750 ° C. at a rate of 100 ° C./hour while supplying nitrogen to the anode of the SOFC cell at 100 mL / min and air to the cathode of the SOFC cell at 100 mL / min. After raising the temperature, the flow rate of the gas on the outlet side of the anode and the flow rate of the gas on the outlet side of the cathode were measured with a flow meter to confirm that there was no leakage. Next, a humidified mixed gas of 6 mL / min of hydrogen and 194 mL / min of nitrogen was supplied to the anode, and air was supplied to the cathode at 400 mL / min. After 10 minutes or more, it was confirmed that no electromotive force was generated and no gas leaked. Thereafter, humidified hydrogen was supplied to the anode at a flow rate of 200 mL / min. After the electromotive force was stabilized, the current density was kept constant at 0.4 A / cm ² and measurement of the output voltage of the SOFC cell was started. The output voltage of the SOFC cell was measured for 50 hours from the start of measurement. The output voltage at the start of SOFC cell measurement was V0, the output voltage of the SOFC cell after 50 hours was V50, and the voltage drop rate after 50 hours was determined by the following equation.
Voltage drop rate [%] = {(V0−V50) / V0} × 100

<Example 1>
(Preparation of anode support substrate green sheet)
60 parts by mass of nickel oxide powder (trade name: “GREEN” manufactured by Shodo Chemical Co., Ltd.) as a conductive component, 3 mol% yttria stabilized zirconia powder (trade name: “TZ3Y” manufactured by Tosoh Corporation) as an electrolyte component ") 40 parts by mass, 10 parts by mass of carbon black (SEC Carbon Co., SGP-3) as a pore forming agent, a binder made of a methacrylate copolymer (molecular weight: 30,000, glass transition temperature: -8 ° C). , Solid content concentration: 50 parts by mass) 30 parts by mass, 2 parts by mass of dibutyl phthalate as a plasticizer and 80 parts by mass of a mixed solvent of toluene / isopropyl alcohol (mass ratio = 3/2) as a dispersion medium are mixed by a ball mill. Thus, a slurry was prepared. This slurry was formed into a sheet by a doctor blade method and dried at 70 ° C. for 5 hours to prepare a 300 μm thick anode supporting substrate green sheet.

(Preparation of anode layer paste)
In a 500 ml pot for ball mill, 120 g of nickel oxide powder (manufactured by Kishida Chemical Co.) as a conductive component, 80 g of 3 mol% yttria stabilized zirconia powder (manufactured by Tosoh, trade name “TZ3Y”) as an electrolyte component, and 500 g of zirconia balls as grinding media were put and dry milled for 10 hours. Thereafter, the powder was taken out from the pot and calcined at 950 ° C. for 1 hour. After loosening the calcined powder, 60 parts by mass of the calcined powder, 2 parts by mass of carbon black (SGP-3, manufactured by SEC Carbon Co.) as a pore-forming agent, α-terpineol as a solvent (Wako Pure) 36 parts by mass of Yaku Kogyo Co., Ltd., 4 parts by mass of ethyl cellulose (manufactured by Wako Pure Chemical Industries) as a binder, 6 parts by mass of dibutyl phthalate (manufactured by Wako Pure Chemical Industries, Ltd.) as a plasticizer, and a commercially available sorbitan fatty acid as a dispersant 4 parts by mass of an ester surfactant is mixed using a mortar, and then pulverized and kneaded using a three-roll mill (EXAKT technologies, model: “M-80S”) to produce an anode layer paste. did.

(Preparation of electrolyte layer paste)
5 parts by mass of ethyl cellulose (manufactured by Wako Pure Chemical Industries, Ltd.) as a binder with respect to 60 parts by mass of 10 mol% scandia 1 mol% ceria stabilized zirconia powder (Daiichi Rare Element Chemical Co., Ltd., trade name “10Sc1CeSZ”) 40 parts by mass of α-terpineol (made by Wako Pure Chemical Industries, Ltd.) as a solvent, 6 parts by mass of dibutyl phthalate (made by Wako Pure Chemical Industries, Ltd.) as a plasticizer, and a commercially available sorbitan acid ester system as a dispersant 5 parts by mass of a surfactant was mixed using a mortar, and then pulverized and kneaded using a three-roll mill (EXAKT technologies, model “M-80S”) to prepare an electrolyte layer paste.

(Preparation of barrier layer paste)
20 mol% samarium-doped ceria (manufactured by Seimi Chemical Co., Ltd., specific surface area: 5.8 m ² / g, 50 volume% diameter D50: 0.8 μm, 90 volume% diameter D90: 2.2 μm) is a binder for 60 parts by mass. 5 parts by mass of ethyl cellulose (manufactured by Wako Pure Chemical Industries, Ltd.), 40 parts by mass of α-terpineol (manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent, and 6 masses of dibutyl phthalate (manufactured by Wako Pure Chemical Industries, Ltd.) as a plasticizer And 5 parts by mass of a commercially available sorbitan acid ester surfactant that is a dispersant are mixed using a mortar and then crushed using a three-roll mill (EXAKT technologies, model “M-80S”). The mixture was kneaded to produce a barrier layer paste.

(Formation of green layer for anode layer)
The anode layer paste was printed on the above-mentioned anode supporting substrate green sheet by screen printing so as to have a thickness of 20 μm, and dried at 100 ° C. for 30 minutes to form an anode layer green layer.

(Formation of green layer for electrolyte layer)
The electrolyte layer paste was printed on the above-described anode layer green layer by screen printing so as to have a thickness of 15 μm, and dried at 100 ° C. for 30 minutes to form an electrolyte layer green layer.

(Formation of green layer for barrier layer)
The barrier layer paste was printed on the above-described electrolyte layer green layer by screen printing so as to have a thickness of 8 μm, and dried at 100 ° C. for 30 minutes to form a barrier layer green layer.

(Half cell firing)
After drying the barrier layer paste, the anode support substrate green sheet on which the barrier layer green layer, the electrolyte layer green layer, and the anode layer green layer were formed was punched into a square shape. Then, the half cell which concerns on Example 1 was obtained by baking at 1300 degreeC for 2 hours. The half cell after firing was a 6 cm × 6 cm square. A plurality of half cells were produced, and the above-described peeling degree was measured for one half cell. The measurement results are shown in Table 1. Moreover, the cathode was formed as follows about the remaining half cells.

(Preparation of cathode paste)
80 parts by mass of powder of La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ (manufactured by Seimi Chemical Co., Ltd.), 20 parts by mass of 20 mol% samaria dope ceria (manufactured by Seimi Chemical Co., Ltd.), 3 parts by mass of ethyl cellulose as a binder and α as a solvent -30 parts by mass of terpineol was mixed using a mortar. Thereafter, the mixture was kneaded using a three roll mill (manufactured by EXAKT technologies, model “M-80S”) to obtain a cathode paste.

(Cathode formation)
The cathode paste was applied to the surface of the above-mentioned half-cell electrolyte layer by screen printing in a 1 cm × 1 cm square with a thickness of 20 μm and dried at 90 ° C. for 1 hour to form a cathode green layer. Thereafter, the half cell on which the cathode green layer was formed was fired at 1150 ° C. for 2 hours to obtain the SOFC cell according to Example 1. As described above, this SOFC cell was subjected to initial power generation performance evaluation, and the voltage drop rate after 50 hours was obtained.

<Example 2>
A half cell according to Example 2 in the same manner as in Example 1 except that an anode layer paste was prepared using 8 mol% yttria-stabilized zirconia powder (product name: “TZ8Y”) as an electrolyte component. And an SOFC cell was obtained.

<Example 3>
Half-cell according to Example 3 in the same manner as in Example 1 except that the anode layer paste was prepared using 10 mol% yttria-stabilized zirconia powder (trade name: “TZ10Y”, manufactured by Tosoh Corporation) as the electrolyte component. And an SOFC cell was obtained.

<Example 4>
A half cell and an SOFC cell according to Example 4 were obtained in the same manner as in Example 1 except that an anode layer paste was prepared using 3 mol% ytterbia stabilized zirconia powder as an electrolyte component.

<Example 5>
A half cell and a SOFC cell according to Example 5 were obtained in the same manner as in Example 1 except that an anode layer paste was prepared using 8 mol% ytterbia stabilized zirconia powder as an electrolyte component.

<Example 6>
A half cell and a SOFC cell according to Example 6 were obtained in the same manner as in Example 1 except that an anode layer paste was prepared using 10 mol% ytterbia stabilized zirconia powder as an electrolyte component.

<Comparative Example 1>
Anode layer paste was prepared using 10 mol% scandia 1 mol% ceria stabilized zirconia powder (manufactured by Daiichi Rare Element Co., Ltd.) as the electrolyte component, and calcining of the electrolyte component powder and the nickel oxide powder was performed. A half cell and a SOFC cell according to Comparative Example 1 were obtained in the same manner as in Example 1 except that it was not performed.

<Comparative example 2>
An anode layer paste was prepared using 6 mol% scandia-stabilized zirconia powder (manufactured by Daiichi Rare Element Co., Ltd.) as the electrolyte component, and the calcination treatment of the electrolyte component powder and the nickel oxide powder was not performed. Except for this, a half cell and a SOFC cell according to Comparative Example 2 were obtained in the same manner as in Example 1.

<Comparative Example 3>
An anode layer paste was prepared using 11 mol% scandia-stabilized zirconia powder (manufactured by Daiichi Rare Element Co., Ltd.) as the electrolyte component, and the calcination treatment of the electrolyte component powder and the nickel oxide powder was not performed. Except for this, a half cell and a SOFC cell according to Comparative Example 3 were obtained in the same manner as in Example 1.

<Comparative example 4>
A half cell and a SOFC cell according to Comparative Example 4 were obtained in the same manner as in Example 2 except that the calcination treatment of the electrolyte component powder and the nickel oxide powder was not performed.

<Comparative Example 5>
A half cell and a SOFC cell according to Comparative Example 5 were obtained in the same manner as in Example 3 except that the calcination treatment of the electrolyte component powder and the nickel oxide powder was not performed.

<Comparative Example 6>
A half cell and SOFC cell according to Comparative Example 6 were obtained in the same manner as in Example 5 except that the calcination treatment of the electrolyte component powder and the nickel oxide powder was not performed.

  About the half cell which concerns on each Example and each comparative example, the measurement of the peeling degree was implemented as mentioned above. The measurement results are shown in Table 1. The SEM photograph used for the measurement of the peeling degree of the half cell of Example 3 is shown in FIG. The SEM photograph used for the measurement of the peeling degree of the half cell of the comparative example 5 is shown in FIG.

  The SOFC cell according to each example and each comparative example was evaluated for initial power generation performance as described above. The results are shown in Table 1.

  As shown in Table 1, the degree of peeling of the half cells according to Examples 1 to 6 was 2 to 7%, which was 10% or less. On the other hand, the peeling degrees of the half cells according to Comparative Examples 1 to 3 all showed a value larger than 10%. While the voltage drop rate of the SOFC cells according to Examples 1 to 6 was 1.1 to 2.5%, the voltage drop rate of the SOFC cells according to Comparative Examples 1 to 3 was 4.2 to 7%. 3%. That is, the SOFC cell according to the example had a lower voltage drop rate than the SOFC cell according to the comparative example, and showed good initial power generation performance.

Claims (4)

A half cell of a solid oxide fuel cell,
An anode including a conductive component and an electrolyte component;
An electrolyte layer formed on one main surface of the anode,
The volume ratio of H ₂ and N ₂ is 1: 9, and the atmosphere is a mixed gas with a pressure of 1 atm, and the temperature is 750 ° C.
After 4 hours left the half-cell in the interior of the electric furnace is state, and are peeling degree of 10% or less with respect to the electrolyte component of the conductive component,
The electrolyte component is ytterbia-stabilized zirconia;
Half-cell. The anode is a fired body of a mixture containing the conductive component powder and the electrolyte component powder;
In the mixture, the conductive component powder and the electrolyte component powder are 800-105.
The half cell according to claim 1, which is calcined at 0 ° C. for 0.2 to 3 hours.   The half cell according to claim 1, wherein the conductive component is nickel oxide. Cathode is formed on the half-cell according to any one of claims 1 to 3 solid oxide fuel cell.

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