JP6208315B2 - Electrochemical cell and method for producing the same - Google Patents

Description

  The present invention relates to an electrochemical cell and a method for producing the same.

  Solid Oxide Fuel Cell (SOFC) is a reducing agent (hydrogen or hydrocarbon, etc.) through an electrolyte membrane having ionic conductivity (oxygen ions or hydrogen ions) under an operating condition of about 600 to 1000 ° C. ) And an oxidizing agent (such as oxygen) react (fuel cell reaction) and take out the energy as electricity.

  On the other hand, Solid Oxide Electrolysis Cell (SOEC) uses the reverse reaction of SOFC as the principle of operation, and electrolyzes high-temperature water vapor through an electrolyte membrane having ionic conductivity, thereby converting hydrogen and oxygen. It is a device to obtain.

  However, when the electrochemical cell as described above is made to function as SOFC and SOEC, the electrochemical cell has a laminate of an air electrode (oxygen electrode) / electrolyte membrane / fuel electrode (hydrogen electrode) as a minimum constituent unit. For example, a solid oxide powder used for an electrolyte membrane is mixed and dispersed with a solvent to form a slurry, which is uniformly spread on a smooth plastic surface using a blade (doctor blade) and dried. After heating and sintering to obtain an electrolyte membrane, an electrode slurry is applied on the electrolyte membrane using a screen printing method, slurry coating, spray coating, or the like, and baked to form the air electrode (oxygen electrode). Then, a fuel electrode (hydrogen electrode) is formed, and the electrochemical cell is manufactured.

  In the above-described method, in the sintering in forming the air electrode (oxygen electrode) and the fuel electrode (hydrogen electrode) on the electrolyte membrane, the air electrode (oxygen electrode) is particularly caused by the high temperature and material components. The electrolyte membrane reacts, and elements in the air electrode (oxygen electrode) may diffuse into the electrolyte membrane, thereby forming an insulating portion in the electrolyte membrane. Since this insulating portion does not contribute to the conduction of oxide ions, the oxide ion conductivity of the electrolyte membrane is deteriorated. In addition, when the electrode support is separately provided to thin the electrolyte membrane, the above tendency becomes more remarkable.

  In order to solve these problems, a reaction suppression layer is formed between the electrolyte membrane and the electrode, particularly the air electrode (oxygen electrode), and the reaction between the electrolyte membrane and the electrode even at high temperatures during sintering and operation. Attempts have been made to suppress the deterioration of the conductivity of oxide ions in the electrolyte membrane. Since the reaction suppression layer is formed to suppress element diffusion due to the reaction between the electrolyte membrane and the electrodes located on both sides thereof, particularly the air electrode (oxygen electrode), a sintering aid is added to the raw material. It is required to add and sinter to form a dense layer.

  However, even if the reaction suppression layer is formed as a dense layer and the reaction between the electrolyte membrane and the electrode is suppressed, depending on the material component of the electrolyte membrane and the material component of the reaction suppression layer, the electrolyte membrane and the adjacent reaction In some cases, a reaction may occur between the suppression layers.

JP 2008-258064 A

  The problem to be solved by the present invention is that in an electrochemical cell in which a reaction suppression layer is formed between an electrolyte membrane and an electrode, mutual diffusion of common elements between the electrolyte membrane and the reaction suppression layer is suppressed, and a solid electrolyte fuel cell (SOFC) ) And the deterioration of characteristics when used as a solid electrolyte electrolytic cell (SOEC).

The electrochemical cell and the method for manufacturing the same according to the present embodiment include an electrolyte membrane that is electrically insulating and exhibits oxygen ion conductivity, and reaction suppression that includes ceria formed on one main surface of the electrolyte membrane. An air electrode or an oxygen electrode formed on the main surface of the reaction suppression layer on the side facing the electrolyte membrane, and a fuel electrode or an air electrode formed on the other main surface side of the electrolyte membrane; , With. The electrolyte membrane is made of stabilized zirconia containing CeO ₂ . The reaction suppression layer includes at least a CeO ₂ solid solution.

  According to the present invention, in an electrochemical cell in which a reaction suppression layer is formed between an electrolyte membrane and an electrode, mutual diffusion of common elements between the electrolyte membrane and the reaction suppression layer is suppressed, and a solid electrolyte fuel cell (SOFC) and a solid electrolyte are suppressed. It is possible to suppress characteristic deterioration when used as an electrolytic cell (SOEC).

It is sectional drawing which shows schematic structure of the electrochemical cell in 1st Embodiment. It is sectional drawing which shows schematic structure of the electrochemical cell in 2nd Embodiment. It is sectional drawing which shows schematic structure of the electrochemical cell in 3rd Embodiment. It is sectional drawing which shows schematic structure of the electrochemical cell in 4th Embodiment. It is a graph which shows the relationship between the thickness of an electrolyte membrane and closed circuit voltage in the electrochemical cell of an Example.

(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of an electrochemical cell in the present embodiment. In addition, although this embodiment demonstrates the case where an electrochemical cell is used as a solid electrolyte fuel cell, the electrochemical cell of this embodiment can also be used as a solid electrolyte cell.

  An electrochemical cell 10 shown in FIG. 1 is electrically insulative, and has an electrolyte film 11 exhibiting electronic insulation and oxygen ion conductivity, and a reaction formed on one main surface 11A side of the electrolyte film 11. The suppression layer 14, the air electrode 12 formed via the reaction suppression layer 14 on one main surface 11A side of the electrolyte membrane 11, and the fuel electrode 13 formed on the other main surface 11B side of the electrolyte membrane 11 including.

The electrolyte membrane 11 can be composed of, for example, stabilized zirconia. In this case, examples of the stabilizer include Y ₂ O ₃ , Sc ₂ O ₃ , Yb ₂ O ₃ , Gd ₂ O ₃ , Nd ₂ O ₃ , CaO, and MgO. In addition to stabilized zirconia, it can also be composed of perovskite oxides such as LaSrGaMg oxide, LaSrGaMgCo oxide, LaSrGaMgCoFe oxide, LaSrGaMgCoFe oxide.

Furthermore, a material containing ceria (CeO ₂ ), specifically, a ceria-based electrolyte solid solution in which Sm ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , La ₂ O _3, etc. are dissolved in CeO ₂ is used. You can also.

  Although the thickness of the electrolyte membrane 11 can be arbitrarily set according to the purpose, it can be set in a range of, for example, 0.001 mm to 0.5 mm. The electrolyte membrane 11 generally has a dense structure because it conducts only oxygen ions and does not allow gas to pass therethrough.

  The air electrode 12 includes a LaSrMn oxide (hereinafter, LSM), a LaSrCo oxide (hereinafter, LSC), a LaSrCoFe oxide (hereinafter, LSCF), a LaSrFe oxide (hereinafter, LSF), a LaSrMnCo oxide (hereinafter, LSMC), LaSrMnCr oxide (hereinafter LSMC), LaCoMn oxide (hereinafter LCM), LaSrCu oxide (hereinafter LSC), LaSrFeNi oxide (hereinafter LSFN), LaNiFe oxide (hereinafter LNF), LaBaCo oxide (hereinafter hereafter) LBC), LaNiCo oxide (hereinafter LNC), LaSrAlFe oxide (hereinafter LSAF), LaSrCoNiCu oxide (hereinafter LSCNC), LaSr-FeNiCu oxide (hereinafter LSFNC), LaNi oxide (hereinafter LN) GdSrCo oxide (hereinafter referred to as G SC), GdSrMn oxide (hereinafter GSM), PrCaMn oxide (hereinafter PCaM), PrSrMn oxide (hereinafter PSM), PrBaCo oxide (hereinafter PBC), SmSrCo oxide (hereinafter SSC), NdSmCo oxidation (Hereinafter referred to as NSC), BiSrCaCu oxide (hereinafter referred to as BSCC), BaLaFeCo oxide (hereinafter referred to as BLFC), BaSrFeCo oxide (hereinafter referred to as BSFC), YSrFeCo oxide (hereinafter referred to as YLFC), YCuCoFe oxide (hereinafter referred to as YCCF) ), YBaCu oxide (hereinafter referred to as YBC), or other materials having electron-ion mixed conductivity.

  In addition, when using the material which has the electron-ion mixed conductivity mentioned above, a composition ratio etc. do not ask | require. Further, a mixture of stabilized zirconia or ceria-based electrolyte solid solution may be used. Further, for example, by adding a metal component such as Pt, Ru, Au, Ag, Pd to the above-described electron-ion mixed conductive material, the above-described electron conductivity and oxide ion conductivity are improved. Oxygen and hydrogen production can be increased more efficiently.

  When the electrochemical cell 10 is used as SOFC, the air electrode 12 is generally formed as a porous body in order to efficiently supply oxygen as a raw material gas. Although the thickness of the air electrode 12 can be arbitrarily set according to the purpose, it can be set in a range of 0.001 mm to 1 mm, for example.

  The fuel electrode 13 can be made of nickel or cermet of nickel oxide and at least one of ceria-based and zirconia-based ceramics. When the fuel electrode 13 is composed of cermet, the mass mixing ratio of nickel oxide and ceramic is set to, for example, 70:30 to 30:70 before the reduction treatment. Note that the nickel oxide is converted to nickel after the reduction treatment.

Examples of the ceria-based ceramics include ceramics in which Sm ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , La ₂ O _{3 and the} like are dissolved in CeO ₂ . Further, examples of the zirconia ceramic particles include stabilized ceramics such as Y ₂ O ₃ , Sc ₂ O ₃ , Yb ₂ O ₃ , Gd ₂ O ₃ , Nd ₂ O ₃ , CaO, and MgO.

  When the electrochemical cell 10 is used as an SOFC, the fuel electrode 13 supplies a reducing gas (a gas containing hydrogen or hydrocarbon as a main component) over the entire fuel electrode 13 to reduce the reducing gas. In order to improve the use efficiency, it is generally formed as a porous body.

  The thickness of the fuel electrode 13 can be 5 μm to 100 μm.

For the reaction suppression layer 14, a ceria-based electrolyte solid solution in which Sm ₂ O ₃ , Gd ₂ O ₃ , Y ₂ O ₃ , La ₂ O _{3 and the} like are dissolved in CeO ₂ can be used. Such a reaction suppression layer 14 is not limited to the material composition of the adjacent electrolyte membrane 11, and the constituent material of the air electrode 12 and the electrolyte membrane can be used even at a high sintering temperature when the air electrode 12 is formed on the electrolyte membrane 11. Reaction with 11 constituent materials can be suppressed.

  The reaction suppression layer 14 is formed to suppress element diffusion due to the reaction between the electrolyte membrane 11 and the air electrode 12 located on both sides of the material composition in addition to the material composition as described above. Therefore, it is necessary to be a dense layer to suppress the element diffusion. Moreover, the thickness of the reaction suppression layer 14 can be 0.01 micrometer-5 micrometers, for example.

  As described above, according to the present embodiment, in the electrochemical cell in which the reaction suppression layer is formed between the electrolyte membrane and the electrode, the reaction between the electrolyte membrane and the reaction suppression layer is suppressed, and the solid electrolyte fuel cell (SOFC) And deterioration of characteristics when used as a solid electrolyte electrolytic cell (SOEC) can be suppressed.

  In addition, as shown in the following examples, the characteristic deterioration when used as a solid electrolyte fuel cell (SOFC) and a solid electrolyte electrolytic cell (SOEC) is suppressed by using a support as described below. When the thickness is reduced to, for example, less than 10 μm, the effect is exhibited most.

The electrochemical cell 20 shown in FIG. 2 is manufactured as follows, for example. For example, a green sheet of the electrolyte membrane 11 and the fuel electrode 13 is produced, and these sheets are bonded together and, for example, co-sintered at 1400 ° C. to form a dense laminate. Thereafter, a solution or slurry containing a ceria (CeO ₂ ) -based solid solution is applied onto the electrolyte membrane 11 of this laminate using spray coating, slurry coating, screen printing, or the like, and then fired, and the obtained reaction suppression layer A green sheet of the air electrode 12 is arranged on the air electrode 14 and then fired to form the air electrode 12.

The reaction suppression layer 14 is formed by depositing a cerium oxide (CeO ₂ ) -based solid solution such as PVD, CVD, EB-PVD, AD method (aerosol deposition), PLD method (pulse laser deposition), or cold spray method. It can also be formed directly by depositing on the electrolyte membrane 11 of the laminate using a surface treatment method such as the above. In this case, in order to control the denseness of the reaction suppression layer 14, the electrolyte membrane 11 serving as a substrate can be heated to an appropriate temperature.

Furthermore, the reaction suppression layer 14 can also be formed by producing a green sheet containing a cerium oxide (CeO ₂ ) -based solid solution, pasting it on the electrolyte membrane 11 and firing it.

  However, if the fuel electrode 13, the electrolyte 11 and the reaction suppression layer 14 are integrally co-sintered from the viewpoint of simplification of the manufacturing process and the like, there is a high possibility of element diffusion between the electrolyte membrane 11 and the reaction suppression layer 14. In particular, when thinning the electrolyte membrane 11 is intended, the influence of element diffusion becomes large.

Specifically, the ceria (CeO ₂ ) -based solid solution constituting the reaction suppression layer 14 is known to exhibit electron conductivity in a reducing atmosphere, and when this component diffuses to the electrolyte membrane 11 side, Also in the electrolyte membrane 11, since the electronic conductivity is expressed, there is a concern that the oxide ion conductivity is lowered. Further, when the electrolyte membrane 11 is also composed of a ceria (CeO ₂ ) -based solid solution, the same component is present in both the electrolyte membrane 11 and the reaction suppression layer 14, so that CeO penetrating the reaction suppression layer 14 from the electrolyte membrane 11. There is a concern that the connection between the _two will increase, and the oxide ion conductivity of the electrolyte membrane 11 will also decrease.

  Therefore, when forming the reaction suppression layer 14, instead of co-sintering as described above, after forming a sintered laminate of the electrolyte membrane 11 and the fuel electrode 13, the reaction suppression layer 14 and the air electrode 12 are made independent. It is preferable to form them.

(Second Embodiment)
FIG. 2 is a cross-sectional view showing a schematic configuration of the electrochemical cell in the present embodiment. In addition, the same code | symbol is used about the same or same component as the electrochemical cell 10 shown in FIG.

  The electrochemical cell 20 of the present embodiment is different from the electrochemical cell 10 of the first embodiment shown in FIG. 1 in that the support material 21 is disposed on the fuel electrode 13. Adopts the same structure.

  The support 21 is porous, and a reducing fuel gas (for example, gas containing hydrogen or hydrocarbon as a main component) supplied to the fuel electrode 13 reaches nickel particles or the like constituting the fuel electrode 13, and The fuel gas is configured to be decomposed into water (water vapor) and oxygen by a catalytic action such as nickel particles.

  Moreover, the thickness of the electrolyte membrane 11 can be reduced by disposing the support 21. When the thickness of the electrolyte membrane 11 is large, it takes a long time for oxygen ions to be conducted through the electrolyte membrane 11, so that the ionic conduction resistance increases. However, when the thickness of the electrolyte membrane 11 is small, the electrolyte membrane 11 is moved through the electrolyte membrane 11. The time required for oxygen ions to be conducted can be shortened, and the ion conduction resistance can be reduced.

The support 21 needs to be made of a material having at least electronic conductivity so that electric power generated between the air electrode 12 and the fuel electrode 13 can be taken out to the outside. It can be composed of a foamed body, a metal fiber body, and a ceramic sintered body having conductivity, and its porosity is determined by, for example, molding pressure when forming a molded body, sintering temperature during sintering, and pore forming material. Due to the type of In particular, the amount of the three-phase interface on the side of the fuel electrode 13 is increased by using an electron-ion mixed conductive ceramic material. Therefore, the electrochemical reaction in the fuel electrode 13 is promoted, and the output characteristics of the electrochemical cell 20 can be improved. Specifically, it can be composed of at least one selected from the group consisting of _Sm 2 _{O 3} doped _CeO 2, _Gd 2 _{O 3} doped CeO _2, and _Y 2 _{O 3} doped CeO _2. Moreover, electroconductivity can also be provided by plating etc. with respect to the porous support body 21 mentioned above.

  The thickness of the support 21 can be, for example, 100 μm or more and 1000 μm or less. If the thickness of the support 21 is smaller than 100 μm, the strength of the support 21 is not sufficient, and the strength of the electrochemical cell 10 is deteriorated. On the other hand, when the thickness of the support 21 is greater than 1000 μm, the conductive resistance increases.

  Note that the porosity of the support 21 is made larger than the porosity of the fuel electrode 13 in order to prevent the supply resistance of the fuel gas from becoming too large at the support 21 and being supplied to the fuel electrode 13.

Also in the present embodiment, as in the first embodiment, a material containing ceria (CeO ₂ ), specifically, CeO ₂ containing Sm ₂ O ₃ , Gd ₂ O ₃ between the electrolyte membrane 11 and the air electrode 12 is used. , Y ₂ O ₃ , La ₂ O ₃ or the like is used as a ceria-based electrolyte solid solution, so that the air electrode 12 is formed on the electrolyte membrane 11 regardless of the material composition of the adjacent electrolyte membrane 11. Even when the sintering reaction temperature is high, the reaction between the temperature reaction suppressing layer 14 and the electrolyte membrane 11 is suppressed. For example, even when the constituent elements of the electrolyte membrane 11 diffuse into the reaction suppressing layer 14, the ceria does not contain these elements. Does not react with.

  Therefore, according to this embodiment, in the electrochemical cell in which the reaction suppression layer is formed between the electrolyte membrane and the electrode, the reaction between the electrolyte membrane and the reaction suppression layer is suppressed, and the solid electrolyte fuel cell (SOFC) and the solid electrolyte electrolysis are suppressed. It is possible to suppress deterioration of characteristics when used as a cell (SOEC).

  In addition, since it is the same as that of the electrochemical cell 10 of 1st Embodiment about another structure, the characteristic, and an effect, description is abbreviate | omitted.

  Further, in this embodiment, the air electrode 12 is disposed above the electrolyte membrane 11 and the fuel electrode 13 is disposed below, but the fuel electrode 13 is disposed above the electrolyte membrane 11 and below. The same applies to the case where the air electrode 12 is provided.

(Third embodiment)
FIG. 3 is a cross-sectional view showing a schematic configuration of the electrochemical cell in the present embodiment. In addition, the same code | symbol is used about the same or same component as the electrochemical cell 10 shown in FIG. 1, and the electrochemical cell 20 shown in FIG.

  In the electrochemical cell 30 of the present embodiment, a mixed layer 35 including the constituent material of the electrolyte membrane 11 and the constituent material of the reaction suppression layer 14 is formed between the solid electrolyte membrane 11 and the reaction suppression layer 14. 2 is different from the electrochemical cell 20 of the first embodiment shown in FIG. 2, and has the same configuration in other respects.

  In the present embodiment, since the mixed layer 35 as described above is provided, the adhesion between the electrolyte 11 and the reaction suppression layer 14 can be improved, and the highly reliable electrochemical cell 30 is provided. Can be provided.

Also in this embodiment, as in the first embodiment, a material containing ceria (CeO ₂ ), specifically, CeO ₂ containing Sm ₂ O ₃ , Gd ₂ between the electrolyte membrane 11 and the air electrode 12. Since a ceria-based electrolyte solid solution in which O ₃ , Y ₂ O ₃ , La ₂ O _{3 and the} like are dissolved is used, the air electrode 12 is formed on the electrolyte film 11 regardless of the material composition of the adjacent electrolyte film 11. Even at a high sintering temperature, the reaction between the temperature reaction suppressing layer 14 and the electrolyte membrane 11 is suppressed, and even when, for example, constituent elements of the electrolyte membrane 11 diffuse into the reaction suppressing layer 14, the ceria is It does not react with any element.

  Therefore, according to this embodiment, in the electrochemical cell in which the reaction suppression layer is formed between the electrolyte membrane and the electrode, the reaction between the electrolyte membrane and the reaction suppression layer is suppressed, and the solid electrolyte fuel cell (SOFC) and the solid electrolyte electrolysis are suppressed. It is possible to suppress deterioration of characteristics when used as a cell (SOEC).

  In addition, since it is the same as that of the electrochemical cell 10 of 1st Embodiment and the electrochemical cell 20 of 2nd Embodiment about another structure, the characteristic, and an effect, description is abbreviate | omitted.

  Further, in this embodiment, the air electrode 12 is disposed above the electrolyte membrane 11 and the fuel electrode 13 is disposed below, but the fuel electrode 13 is disposed above the electrolyte membrane 11 and below. The same applies to the case where the air electrode 12 is provided.

(Fourth embodiment)
FIG. 4 is a cross-sectional view showing a schematic configuration of the electrochemical cell in the present embodiment. In addition, the same code | symbol is used about the same or same component as the electrochemical cell 10 shown in FIG. 1, and the electrochemical cell 20 shown in FIG.

  In the electrochemical cell 40 of the present embodiment, the uneven portion 11A is formed on the main surface of the electrolyte membrane 11 on the reaction suppression layer 14 side, and the reaction suppression layer 14 is embedded in the uneven portion 11A of the electrolyte membrane 11. It is different from the electrochemical cell 20 of the first embodiment shown in FIG. 2 in that it is formed, and has the same configuration in other points.

  In the present embodiment, since the concavo-convex portion 11A is formed on the main surface of the electrolyte membrane 11, the interface length between the electrolyte membrane 11 and the reaction suppression layer 14 is increased, and an anchor effect is generated at the location. Become. Therefore, adhesion between the electrolyte membrane 11 and the reaction suppression layer 14 can be improved, and the highly reliable electrochemical cell 40 can be provided.

  The uneven portion 11A of the electrolyte film 11 can be formed by blasting after the electrolyte film 11 is formed by baking, or the electrolyte film 11 can be formed by a vapor deposition method through a mask.

Also in this embodiment, as in the first embodiment, a material containing ceria (CeO ₂ ), specifically, CeO ₂ containing Sm ₂ O ₃ , Gd ₂ between the electrolyte membrane 11 and the air electrode 12. Since a ceria-based electrolyte solid solution in which O ₃ , Y ₂ O ₃ , La ₂ O _{3 and the} like are dissolved is used, the air electrode 12 is formed on the electrolyte film 11 regardless of the material composition of the adjacent electrolyte film 11. Even at a high sintering temperature, the reaction between the temperature reaction suppressing layer 14 and the electrolyte membrane 11 is suppressed, and even when, for example, constituent elements of the electrolyte membrane 11 diffuse into the reaction suppressing layer 14, the ceria is It does not react with any element.

  Therefore, according to this embodiment, in the electrochemical cell in which the reaction suppression layer is formed between the electrolyte membrane and the electrode, the reaction between the electrolyte membrane and the reaction suppression layer is suppressed, and the solid electrolyte fuel cell (SOFC) and the solid electrolyte electrolysis are suppressed. It is possible to suppress deterioration of characteristics when used as a cell (SOEC).

  In addition, since it is the same as that of the electrochemical cell 10 of 1st Embodiment and the electrochemical cell 20 of 2nd Embodiment about another structure, the characteristic, and an effect, description is abbreviate | omitted.

  Further, in this embodiment, the air electrode 12 is disposed above the electrolyte membrane 11 and the fuel electrode 13 is disposed below, but the fuel electrode 13 is disposed above the electrolyte membrane 11 and below. The same applies to the case where the air electrode 12 is provided.

In this example, an electrochemical cell 20 having a configuration as shown in FIG. 2 was produced.
The electrolyte membrane 11 uses scandia-stabilized zirconia (10Sc1CeSz) containing 1 mol% CeO ₂ having a thickness of 6 μm, 7 μm, and 12 μm, and the air electrode 12 is made of LaSrCoFe oxide having a thickness of 30 μm to 50 μm. In this case, NiO—YSZ having a thickness of 30 μm was used. For the reaction suppression layer 14, a CeO ₂ —Gd ₂ O ₃ solid solution (GDC) having a thickness of 1 μm to 5 μm was used. The support 21 was also made of an electrode cell 20 using NiO-YSZ having a thickness of 0.5 mm to 0.7 mm.

  The operating temperature of the electrode cell 20 obtained in this way is set to 800 ° C., and a mixed gas of fuel gas (hydrogen and water vapor (hydrogen: water vapor = 50: 50 vol%)) is supplied to the fuel electrode 13, and the air electrode 12 was supplied with air (oxygen and nitrogen (oxygen: nitrogen = 20: 80% by volume)) and operated for 100 hours.

  For comparison, an electrochemical cell in which the reaction suppression layer 14 was formed was produced and evaluated in the same manner as described above. The results are shown in FIG.

  As is clear from FIG. 5, the electrochemical cell 20 obtained according to the second embodiment described above shows a constant open circuit voltage (OCV) even when the thickness of the electrolyte membrane 11 is 10 μm or less. In an electrochemical cell in which no reaction suppression layer is present, it can be seen that when the thickness of the electrolyte membrane 11 is less than 10 μm, the open circuit voltage (OCV) rapidly decreases.

  Therefore, by the presence of the reaction suppression layer 14 made of a ceria-containing solid solution, the reaction between the electrolyte membrane 11 and the reaction suppression layer 14 is suppressed, and the reaction between the electrolyte membrane 11 and the air electrode 12 is also suppressed. It was found that the open circuit voltage (OCV), which is a characteristic of the electrochemical cell 20, is kept constant. On the other hand, when the reaction suppression layer 14 is not present, the electrolyte membrane 11 and the air electrode 12 react to form an insulating portion in the electrolyte membrane 11, so that the open circuit voltage (OCV) is reduced. I understand.

  As mentioned above, although several embodiment of this invention was described, these embodiment was posted as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

10, 20, 30, 40 Electrochemical cell 11 Electrolyte membrane 11A Concavity and convexity 12 Air electrode 13 Fuel electrode 14 Reaction suppression layer 21 Support 35 Mixed layer

Claims (7)

An electrolyte membrane that is electrically insulating and exhibits oxygen ion conductivity;
A reaction suppression layer containing ceria formed on one main surface side of the electrolyte membrane;
An air electrode or an oxygen electrode formed on the main surface of the reaction suppression layer on the side facing the electrolyte membrane;
A fuel electrode or a hydrogen electrode formed on the other main surface side of the electrolyte membrane;
With
The electrolyte membrane is made of stabilized zirconia containing CeO ₂ ,
The electrochemical cell, wherein the reaction suppression layer includes at least a CeO ₂ solid solution.   The electrochemical cell according to claim 1, further comprising a porous support for holding at least one of the air electrode or oxygen electrode and the fuel electrode or hydrogen electrode.   The electrochemical cell according to claim 1, further comprising a mixed layer including a constituent material of the electrolyte membrane and a constituent material of the reaction suppression layer between the electrolyte membrane and the reaction suppression layer.   The electrochemical cell according to claim 1 or 2, wherein the one main surface of the electrolyte is formed in an uneven shape. A method for producing an electrochemical cell according to any one of claims 1 to 4,
A step of forming a laminate of an electrolyte membrane that is electrically insulating and exhibits oxygen ion conductivity and a fuel electrode or a hydrogen electrode by firing;
On the side of the laminate opposite to the fuel electrode or the hydrogen electrode, a step of applying the raw material solution or slurry containing ceria of the reaction suppression layer and baking it to form the reaction suppression layer;
A step of forming an air electrode or an oxygen electrode by firing on the side of the reaction suppression layer facing the laminate; and
A method for producing an electrochemical cell, comprising: A method for producing an electrochemical cell according to any one of claims 1 to 4,
A step of forming a laminate of an electrolyte membrane that is electrically insulating and exhibits oxygen ion conductivity and a fuel electrode or a hydrogen electrode by firing;
Forming the reaction suppression layer by forming a film made of a raw material containing ceria of the reaction suppression layer on the side of the laminate opposite to the fuel electrode or the hydrogen electrode by a vapor deposition method or a surface treatment method;
A step of forming an air electrode or an oxygen electrode by firing on the side of the reaction suppression layer facing the laminate; and
A method for producing an electrochemical cell, comprising: A method for producing an electrochemical cell according to any one of claims 1 to 4,
A step of forming a laminate of an electrolyte membrane that is electrically insulating and exhibits oxygen ion conductivity and a fuel electrode or a hydrogen electrode by firing;
A step of laminating a green sheet of a raw material containing ceria of the reaction suppression layer on the side of the laminate opposite to the fuel electrode or the hydrogen electrode, and firing the green sheet to form the reaction suppression layer;
A step of forming an air electrode or an oxygen electrode by firing on the side of the reaction suppression layer facing the laminate; and
A method for producing an electrochemical cell, comprising:

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