WO2023195245A1 - Electrochemical cell - Google Patents

Electrochemical cell Download PDF

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Publication number
WO2023195245A1
WO2023195245A1 PCT/JP2023/005684 JP2023005684W WO2023195245A1 WO 2023195245 A1 WO2023195245 A1 WO 2023195245A1 JP 2023005684 W JP2023005684 W JP 2023005684W WO 2023195245 A1 WO2023195245 A1 WO 2023195245A1
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Prior art keywords
hydrogen electrode
intermediate layer
layer
support layer
electrode
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PCT/JP2023/005684
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French (fr)
Japanese (ja)
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隆平 小原
陽平 岡田
真司 藤崎
誠 大森
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日本碍子株式会社
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Publication of WO2023195245A1 publication Critical patent/WO2023195245A1/en

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/042—Electrodes formed of a single material
    • C25B11/046—Alloys
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/042—Electrodes formed of a single material
    • C25B11/047—Ceramics
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
    • C25B9/23—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms comprising ion-exchange membranes in or on which electrode material is embedded
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/60—Constructional parts of cells
    • C25B9/63—Holders for electrodes; Positioning of the electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M8/1213—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the electrode/electrolyte combination or the supporting material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M8/1213—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the electrode/electrolyte combination or the supporting material
    • H01M8/1226—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the electrode/electrolyte combination or the supporting material characterised by the supporting layer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to an electrochemical cell.
  • An anode-supported fuel cell is known as an example of an electrochemical cell (see, for example, Patent Document 1).
  • An anode-supported fuel cell includes a support layer, a hydrogen electrode disposed on the support layer, an oxygen electrode, and an electrolyte disposed between the hydrogen electrode and the oxygen electrode.
  • the support layer can be composed of YSZ (yttria stabilized zirconia) and Ni (nickel), and the hydrogen electrode can be composed of ceria-based oxide added with a rare earth element and Ni. Ni contained in each of the hydrogen electrode and the support layer exists in the form of NiO in the oxidizing atmosphere.
  • NiO contained in the support layer and the hydrogen electrode is reduced to Ni, so that a volume change occurs in each of the support layer and the hydrogen electrode.
  • ceria (CeO 2 ) in the hydrogen electrode has a large expansion amount in a reducing atmosphere
  • zirconia (ZrO 2 ) in the support layer has a relatively small expansion amount in a reducing atmosphere.
  • a difference in the amount of expansion occurs between the hydrogen electrode and the support layer. If startup and shutdown are repeated under this condition, cracks will occur due to stress accumulated within the hydrogen electrode.
  • An object of the present invention is to provide an electrochemical cell that can suppress cracks in the hydrogen electrode.
  • the electrochemical cell according to the present invention includes a support layer, an intermediate layer disposed on the support layer, a hydrogen electrode disposed on the intermediate layer, an oxygen electrode, and an intermediate layer disposed between the hydrogen electrode and the oxygen electrode. and an electrolyte.
  • the support layer is composed of yttria-stabilized zirconia and nickel.
  • the hydrogen electrode is composed of ceria-based oxide to which rare earth elements are added and nickel.
  • the intermediate layer is composed of yttria-stabilized zirconia, a solid solution of ceria-based oxide added with a rare earth element, and nickel.
  • FIG. 1 is a cross-sectional view of a fuel cell.
  • the fuel cell 10 is a so-called anode-supported fuel cell.
  • the fuel cell 10 includes a support layer 11 , an intermediate layer 12 , a hydrogen electrode 13 , an electrolyte 14 , a reaction prevention layer 15 , and an oxygen electrode 16 .
  • Support layer 11 supports intermediate layer 12 .
  • the shape of the support layer 11 is not particularly limited, it can be formed into, for example, a plate shape, a hollow plate shape, a cylindrical shape, or the like.
  • the support layer 11 is made of a porous material that has electronic conductivity. Specifically, the support layer 11 contains YSZ (yttria stabilized zirconia) and Ni (nickel). As YSZ, ZrO 2 (zirconia) stabilized with Y 2 O 3 (yttria) of 3 mol % or more and 10 mol % or less can be used. Ni becomes metallic Ni in a reducing atmosphere where fuel gas is supplied, and becomes NiO in an oxidizing atmosphere where fuel gas is not supplied.
  • the content of YSZ in the support layer 11 can be 25 mol% or more and 55 mol% or less.
  • the Ni content in the support layer 11 can be 45 mol% or more and 75 mol% or less in terms of NiO.
  • the respective contents of YSZ and Ni in the support layer 11 are obtained by line analysis using an atomic concentration profile, that is, elemental mapping using an EPMA (Electron Probe Micro Analyzer). Specifically, in a cross section along the thickness direction, line analysis is performed in the thickness direction using EPMA, thereby obtaining concentration distribution data of each element.
  • EPMA is a concept that includes EDS (Energy Dispersive x-ray Spectroscopy).
  • the porosity of the support layer 11 can be, for example, 10% or more and 50% or less. In this specification, porosity is the ratio of the area of the gas phase to the total area of the solid phase and gas phase in cross-sectional observation using a SEM (scanning electron microscope).
  • the thickness of the support layer 11 can be, for example, 50 ⁇ m or more and 1 mm or less.
  • Intermediate layer 12 is arranged on support layer 11 .
  • Intermediate layer 12 is arranged between support layer 11 and hydrogen electrode 13 .
  • the intermediate layer 12 is made of a porous material having electronic conductivity and ionic conductivity.
  • the intermediate layer 12 includes Ni and a solid solution of ceria-based oxide to which YSZ and a rare earth element are added.
  • a solid solution is one in which YSZ and a ceria-based oxide to which a rare earth element is added are dissolved together to form a uniform solid phase.
  • the NiO contained in the support layer 11 and the hydrogen electrode 13 is reduced to Ni, so the volume changes in the support layer 11 and the hydrogen electrode 13, respectively. occurs.
  • CeO 2 in the hydrogen electrode 13 has a large expansion amount in a reducing atmosphere
  • ZrO 2 in the support layer 11 has a relatively small expansion amount in a reducing atmosphere. A difference in the amount of expansion occurs between the support layers 11. If the fuel cell 10 is repeatedly started and stopped under this condition, cracks are likely to occur due to stress accumulated within the hydrogen electrode 13.
  • the intermediate layer 12 contains both YSZ, which is a constituent material of the support layer 11, and a ceria-based oxide added with a rare earth element, which is a constituent material of the hydrogen electrode 13, which will be described later. There is.
  • This intermediate layer 12 functions as a buffer layer that buffers the difference in the amount of expansion between the hydrogen electrode 13 and the support layer 11, so that the inside of the hydrogen electrode 13 is smaller than when the support layer 11 and the hydrogen electrode 13 are directly connected. Accumulation of stress can be suppressed. Therefore, generation of cracks in the hydrogen electrode 13 can be suppressed.
  • the intermediate layer 12 is a region between the support layer 11 and the hydrogen electrode 13 in which a solid solution of ceria-based oxide to which YSZ and a rare earth element are added exists.
  • ceria-based oxides doped with rare earth elements include, but are not limited to, gadolinium-doped ceria (GDC), samarium-doped ceria (SDC), and yttrium-doped ceria (YDC).
  • GDC gadolinium-doped ceria
  • SDC samarium-doped ceria
  • YDC yttrium-doped ceria
  • CeO 2 (ceria) doped with an oxide of Gd (gadolinium) of 5 mol % or more and 20 mol % or less can be used.
  • Ni becomes metallic Ni in a reducing atmosphere where fuel gas is supplied, and becomes NiO in an oxidizing atmosphere where fuel gas is not supplied.
  • the content of YSZ in the intermediate layer 12 can be 15 mol% or more and 35 mol% or less.
  • the content of the ceria-based oxide to which a rare earth element is added in the intermediate layer 12 can be 15 mol% or more and 35 mol% or less.
  • the content of Ni in the intermediate layer 12 can be 35 mol% or more and 65 mol% or less in terms of NiO.
  • the respective contents of YSZ, rare earth element-added ceria-based oxide, and Ni in the support layer 11 are obtained by line analysis using the atomic concentration profile described above.
  • the thickness of the intermediate layer 12 can be, for example, 1 ⁇ m or more and 50 ⁇ m or less.
  • the thickness of the intermediate layer 12 is preferably 20 ⁇ m or less.
  • the thickness of the intermediate layer 12 is preferably 3 ⁇ m or more. Thereby, it is possible to further suppress the occurrence of cracks in the hydrogen electrode 13. Therefore, by setting the thickness of the intermediate layer 12 to 3 ⁇ m or more and 20 ⁇ m or less, it is possible to both ensure the initial performance of the fuel cell 10 and further suppress cracks.
  • the thickness of the intermediate layer 12 is determined by observing a cross section of the intermediate layer 12 along the thickness direction at 1000 times magnification using FE-SEM, and determining the thickness of the intermediate layer 12 at five points randomly selected from the observed image. is obtained by taking the arithmetic mean of The thickness direction is a direction perpendicular to the surface of the electrolyte 14 on the hydrogen electrode side.
  • the porosity of the intermediate layer 12 can be, for example, 10% or more and 50% or less.
  • Hydrogen electrode 13 is placed on intermediate layer 12 . Hydrogen electrode 13 is placed between intermediate layer 12 and electrolyte 14 . Fuel gas is supplied to the hydrogen electrode 13 via the support layer 11 and the intermediate layer 12 . At the hydrogen electrode 13, an electrode reaction expressed by the following formula (1) occurs.
  • the hydrogen electrode 13 is made of a porous material having electronic conductivity and ionic conductivity.
  • the hydrogen electrode 13 includes a ceria-based oxide to which a rare earth element is added and Ni.
  • ceria-based oxides doped with rare earth elements include, but are not limited to, GDC, SDC, and YDC.
  • GDC CeO 2 (ceria) doped with an oxide of Gd (gadolinium) of 5 mol % or more and 20 mol % or less can be used.
  • Gd gadolinium
  • the rare earth element-doped ceria-based oxide contained in the hydrogen electrode 13 may be the same or different from the rare-earth element-added ceria-based oxide contained in the intermediate layer 12 .
  • Ni becomes metallic Ni in a reducing atmosphere where fuel gas is supplied, and becomes NiO in an oxidizing atmosphere where fuel gas is not supplied.
  • the hydrogen electrode 13 contracts and expands in response to the reduction and oxidation of Ni, but as described above, the change in volume of the hydrogen electrode 13 is absorbed by the intermediate layer 12, which causes cracks to occur in the hydrogen electrode 13. is suppressed.
  • the content of the ceria-based oxide to which rare earth elements are added in the hydrogen electrode 13 can be set to 35 mol% or more and 65 mol% or less.
  • the Ni content in the hydrogen electrode 13 can be 35 mol% or more and 65 mol% or less in terms of NiO.
  • the respective contents of ceria-based oxide to which a rare earth element is added and Ni in the hydrogen electrode 13 are obtained by line analysis using the atomic concentration profile described above.
  • the porosity of the hydrogen electrode 13 can be, for example, 10% or more and 50% or less.
  • the thickness of the hydrogen electrode 13 can be, for example, 5 ⁇ m or more and 0.1 mm or less.
  • Electrolyte 14 is placed on hydrogen electrode 13 . Electrolyte 14 is placed between hydrogen electrode 13 and oxygen electrode 16. In this embodiment, since the fuel cell 10 includes the reaction prevention layer 15, the electrolyte 14 is sandwiched between the hydrogen electrode 13 and the reaction prevention layer 15.
  • the electrolyte 14 is made of a dense material that has ionic conductivity and no electronic conductivity.
  • the electrolyte 14 is, for example, ZrO 2 stabilized with Y 2 O 3 , CeO 2 , Sc 2 O 3 , Yb 2 O 3 or the like, or doped with Y 2 O 3 , Sm 2 O 3 , Gd 2 O 3 or the like. It can be composed of CeO 2 .
  • the electrolyte 14 is lanthanum gallate, or a lanthanum gallate type perovskite structure in which part of the lanthanum or gallium of the lanthanum gallate is replaced with strontium, calcium, barium, magnesium, aluminum, indium, cobalt, iron, nickel, copper, etc. It can be composed of an oxide.
  • the electrolyte 14 may be composed of one type of electrolyte material, or may be composed of two or more types of electrolyte materials.
  • the porosity of the electrolyte 14 can be, for example, 0% or more and 7% or less.
  • the thickness of the electrolyte 14 can be, for example, 3 ⁇ m or more and 50 ⁇ m or less. Note that the electrolyte 14 may have a single layer structure or a multilayer structure.
  • Reaction prevention layer 15 is placed on electrolyte 14 . Reaction prevention layer 15 is arranged between electrolyte 14 and oxygen electrode 16. The reaction prevention layer 15 is provided to prevent the constituent materials of the electrolyte 14 and the constituent materials of the oxygen electrode 16 from reacting to form a reaction layer with high electrical resistance.
  • the reaction prevention layer 15 is made of an ion conductive material.
  • the reaction prevention layer 15 can be made of ceria doped with oxides of rare earth elements such as Gd, Sm, and Y, for example.
  • the porosity of the reaction prevention layer 15 can be, for example, 0.1% or more and 50% or less.
  • the thickness of the reaction prevention layer 15 can be, for example, 1 ⁇ m or more and 50 ⁇ m or less.
  • Oxygen electrode 16 is placed on reaction prevention layer 15 .
  • the oxygen electrode 16 is supplied with a gas containing oxygen (for example, air).
  • a gas containing oxygen for example, air
  • the oxygen electrode 16 is made of a porous material that has electronic conductivity.
  • the porosity of the oxygen electrode 16 can be, for example, 10% or more and 50% or less.
  • the thickness of the oxygen electrode 16 can be, for example, 10 ⁇ m or more and 100 ⁇ m or less.
  • An electrochemical cell consists of an element with a pair of electrodes arranged so that an electromotive force is generated from the overall redox reaction, and an element that converts chemical energy into electrical energy. It is a generic term.
  • Electrochemical cells include anode-supported fuel cells, horizontal striped fuel cells, vertical striped fuel cells, flat plate fuel cells, cylindrical fuel cells, and water electrolysis cells. Examples include electrolytic cells that generate hydrogen using reactions. Furthermore, in the above embodiments, O 2 - (oxygen ions) are used as carriers, but OH - (hydroxide ions) or protons may be used as carriers.
  • the fuel cell 10 is provided with the reaction prevention layer 15, but the reaction prevention layer 15 may not be provided.
  • Electrolytic cells according to Examples 1 to 7 were produced as follows.
  • a support layer molded body was produced by sheet-molding a support layer slurry containing a mixture of YSZ powder, NiO powder, binder, pore-forming agent, plasticizer, dispersion medium, and solvent.
  • an intermediate layer paste prepared by mixing YSZ powder, GDC powder, NiO powder, binder, pore-forming agent, plasticizer, dispersion medium, and solvent is printed on the support layer molded body.
  • a molded body was formed.
  • the thickness of each intermediate layer of Examples 1 to 7 was adjusted as shown in Table 1 by changing the printing thickness of the intermediate layer paste.
  • a hydrogen electrode paste prepared by mixing GDC powder, NiO powder, binder, pore-forming agent, plasticizer, dispersion medium, and solvent is printed on the intermediate layer molded body to form a hydrogen electrode molded body. Formed.
  • an electrolyte molded body was formed by printing an electrolyte paste prepared by mixing YSZ powder, a binder, a plasticizer, a dispersion medium, and a solvent onto the hydrogen electrode molded body.
  • reaction prevention layer molded body was formed by printing a reaction prevention layer paste prepared by mixing GDC powder, a binder, and a solvent onto the electrolyte molded body.
  • the support layer, the intermediate layer, the hydrogen electrode, and the electrolyte are formed by firing (1300°C, 5 hours) the laminate of the support layer molded body, the intermediate layer molded body, the hydrogen electrode molded body, the electrolyte molded body, and the reaction prevention layer molded body.
  • a fired body consisting of a reaction prevention layer and a reaction prevention layer was produced.
  • An oxygen electrode molded body was formed by printing an oxygen electrode paste prepared by mixing LSCF powder, a binder, and a solvent onto the reaction prevention layer.
  • the oxygen electrode molded body was fired (1050°C, 2 hours) to obtain electrolytic cells according to Examples 1 to 7.
  • Heat cycle test A first thermal cycle test was conducted on the electrolytic cells according to Examples 1 to 7 and Comparative Example 1. Specifically, while supplying Ar gas and hydrogen gas (4% relative to Ar gas) to the hydrogen electrode, the temperature is raised from room temperature to 750°C in 2 hours, and then the temperature is lowered from 750°C to room temperature in 4 hours. The process was repeated 10 times as one cycle.
  • Example 7 in which the thickness of the intermediate layer was 20 ⁇ m or less, it was possible to suppress the initial performance from becoming lower than in Example 7. This result was obtained because the ion conduction path within the intermediate layer was prevented from being cut.
  • Example 2 in which the thickness of the intermediate layer was 3 ⁇ m or more, the generation of cracks in the hydrogen electrode was further suppressed compared to Example 1.
  • Fuel cell 11 Support layer 12 Intermediate layer 13 Hydrogen electrode 14 Electrolyte 15 Reaction prevention layer 16 Oxygen electrode

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Abstract

This electrochemical cell (10) comprises: a support layer (11); an intermediate layer (12) located on the support layer (11); a hydrogen electrode (13) located on the intermediate layer (12); an electrolyte (14); and an oxygen electrode (16). The support layer (11) is composed of YSZ and Ni. The hydrogen electrode (13) is composed of a ceria oxide having a rare earth element added thereto, and Ni. The intermediate layer (12) is composed of a solid solution of YSZ and a ceria oxide having a rare earth element added thereto, and Ni.

Description

電気化学セルelectrochemical cell
　本発明は、電気化学セルに関するものである。 The present invention relates to an electrochemical cell.
　電気化学セルの一例としてアノード支持型の燃料電池が知られている（例えば、特許文献１参照）。アノード支持型の燃料電池は、支持層と、支持層上に配置される水素極と、酸素極と、水素極及び酸素極の間に配置される電解質とを備える。 An anode-supported fuel cell is known as an example of an electrochemical cell (see, for example, Patent Document 1). An anode-supported fuel cell includes a support layer, a hydrogen electrode disposed on the support layer, an oxygen electrode, and an electrolyte disposed between the hydrogen electrode and the oxygen electrode.
　支持層は、ＹＳＺ（イットリア安定化ジルコニア）とＮｉ（ニッケル）とによって構成することができ、水素極は、希土類元素が添加されたセリア系酸化物とＮｉとによって構成することができる。水素極及び支持層それぞれが含むＮｉは、酸化雰囲気においてＮｉＯの形態で存在する。 The support layer can be composed of YSZ (yttria stabilized zirconia) and Ni (nickel), and the hydrogen electrode can be composed of ceria-based oxide added with a rare earth element and Ni. Ni contained in each of the hydrogen electrode and the support layer exists in the form of NiO in the oxidizing atmosphere.
特開２０１７－１２３２３１号公報JP2017-123231A
　支持層及び水素極が還元雰囲気に曝されると、支持層及び水素極に含まれるＮｉＯは還元されてＮｉとなるため、支持層及び水素極それぞれに体積変化が生じる。加えて、水素極中のセリア（ＣｅＯ２）は還元雰囲気における膨張量が大きいのに対して、支持層中のジルコニア（ＺｒＯ２）は還元雰囲気における膨張量が相対的に小さいため、還元雰囲気では水素極と支持層の間に膨張量差が生じる。この状況下で起動及び停止が繰り返されると、水素極内に蓄積される応力によってクラックが生じてしまう。 When the support layer and the hydrogen electrode are exposed to a reducing atmosphere, NiO contained in the support layer and the hydrogen electrode is reduced to Ni, so that a volume change occurs in each of the support layer and the hydrogen electrode. In addition, ceria (CeO 2 ) in the hydrogen electrode has a large expansion amount in a reducing atmosphere, whereas zirconia (ZrO 2 ) in the support layer has a relatively small expansion amount in a reducing atmosphere. A difference in the amount of expansion occurs between the hydrogen electrode and the support layer. If startup and shutdown are repeated under this condition, cracks will occur due to stress accumulated within the hydrogen electrode.
　本発明の課題は、水素極のクラックを抑制可能な電気化学セルを提供することである。 An object of the present invention is to provide an electrochemical cell that can suppress cracks in the hydrogen electrode.
　本発明に係る電気化学セルは、支持層と、支持層上に配置される中間層と、中間層上に配置される水素極と、酸素極と、水素極及び酸素極の間に配置される電解質とを備える。支持層は、イットリア安定化ジルコニアと、ニッケルとによって構成される。水素極は、希土類元素が添加されたセリア系酸化物と、ニッケルとによって構成される。中間層は、イットリア安定化ジルコニア及び希土類元素が添加されたセリア系酸化物の固溶体と、ニッケルとによって構成される。 The electrochemical cell according to the present invention includes a support layer, an intermediate layer disposed on the support layer, a hydrogen electrode disposed on the intermediate layer, an oxygen electrode, and an intermediate layer disposed between the hydrogen electrode and the oxygen electrode. and an electrolyte. The support layer is composed of yttria-stabilized zirconia and nickel. The hydrogen electrode is composed of ceria-based oxide to which rare earth elements are added and nickel. The intermediate layer is composed of yttria-stabilized zirconia, a solid solution of ceria-based oxide added with a rare earth element, and nickel.
　本発明によれば、水素極のクラックを抑制可能な電気化学セルを提供することができる。 According to the present invention, it is possible to provide an electrochemical cell that can suppress cracks in the hydrogen electrode.
図１は、燃料電池セルの断面図である。FIG. 1 is a cross-sectional view of a fuel cell.
　（燃料電池セル１０）
　燃料電池セル１０は、いわゆるアノード支持型の燃料電池セルである。燃料電池セル１０は、支持層１１、中間層１２、水素極１３、電解質１４、反応防止層１５、及び酸素極１６を備える。 (Fuel cell cell 10)
The fuel cell 10 is a so-called anode-supported fuel cell. The fuel cell 10 includes a support layer 11 , an intermediate layer 12 , a hydrogen electrode 13 , an electrolyte 14 , a reaction prevention layer 15 , and an oxygen electrode 16 .
　［支持層１１］
　支持層１１は、中間層１２を支持する。支持層１１の形状は特に限られないが、例えば板状、中空板状、円筒状などに形成することができる。 [Support layer 11]
Support layer 11 supports intermediate layer 12 . Although the shape of the support layer 11 is not particularly limited, it can be formed into, for example, a plate shape, a hollow plate shape, a cylindrical shape, or the like.
　支持層１１は、電子伝導性を有する多孔質材料によって構成される。具体的には、支持層１１は、ＹＳＺ（イットリア安定化ジルコニア）とＮｉ（ニッケル）とを含む。ＹＳＺとしては、３ｍｏｌ％以上１０ｍｏｌ％以下のＹ２Ｏ３（イットリア）で安定化されたＺｒＯ２（ジルコニア）を用いることができる。Ｎｉは、燃料ガスが供給された還元雰囲気では金属Ｎｉとなり、燃料ガスが供給されない酸化雰囲気ではＮｉＯとなる。 The support layer 11 is made of a porous material that has electronic conductivity. Specifically, the support layer 11 contains YSZ (yttria stabilized zirconia) and Ni (nickel). As YSZ, ZrO 2 (zirconia) stabilized with Y 2 O 3 (yttria) of 3 mol % or more and 10 mol % or less can be used. Ni becomes metallic Ni in a reducing atmosphere where fuel gas is supplied, and becomes NiO in an oxidizing atmosphere where fuel gas is not supplied.
　支持層１１におけるＹＳＺの含有率は、２５ｍｏｌ％以上５５ｍｏｌ％以下とすることができる。支持層１１におけるＮｉの含有率は、ＮｉＯ換算で４５ｍｏｌ％以上７５ｍｏｌ％以下とすることができる。 The content of YSZ in the support layer 11 can be 25 mol% or more and 55 mol% or less. The Ni content in the support layer 11 can be 45 mol% or more and 75 mol% or less in terms of NiO.
　支持層１１におけるＹＳＺ及びＮｉそれぞれの含有率は、原子濃度プロファイルによるライン分析、すなわちＥＰＭＡ（Ｅｌｅｃｔｒｏｎ　Ｐｒｏｂｅ　Ｍｉｃｒｏ　Ａｎａｌｙｚｅｒ）を用いた元素マッピングによって得られる。具体的には、厚み方向に沿った断面において、ＥＰＭＡを用いて厚み方向にライン分析を行うことにより、各元素の濃度分布データが取得される。なお、ＥＰＭＡは、ＥＤＳ（Ｅｎｅｒｇｙ　Ｄｉｓｐｅｒｓｉｖｅ　ｘ－ｒａｙ　Ｓｐｅｃｔｒｏｓｃｏｐｙ）を含む概念である。 The respective contents of YSZ and Ni in the support layer 11 are obtained by line analysis using an atomic concentration profile, that is, elemental mapping using an EPMA (Electron Probe Micro Analyzer). Specifically, in a cross section along the thickness direction, line analysis is performed in the thickness direction using EPMA, thereby obtaining concentration distribution data of each element. Note that EPMA is a concept that includes EDS (Energy Dispersive x-ray Spectroscopy).
　支持層１１の気孔率は、例えば、１０％以上５０％以下とすることができる。本明細書において、気孔率とは、ＳＥＭ（走査電子顕微鏡）を用いた断面観察における固相と気相の総面積に対する気相の面積の割合である。支持層１１の厚さは、例えば、５０μｍ以上１ｍｍ以下とすることができる。 The porosity of the support layer 11 can be, for example, 10% or more and 50% or less. In this specification, porosity is the ratio of the area of the gas phase to the total area of the solid phase and gas phase in cross-sectional observation using a SEM (scanning electron microscope). The thickness of the support layer 11 can be, for example, 50 μm or more and 1 mm or less.
　［中間層１２］
　中間層１２は、支持層１１上に配置される。中間層１２は、支持層１１と水素極１３の間に配置される。 [Middle layer 12]
Intermediate layer 12 is arranged on support layer 11 . Intermediate layer 12 is arranged between support layer 11 and hydrogen electrode 13 .
　中間層１２は、電子伝導性及びイオン伝導性を有する多孔質材料によって構成される。具体的には、中間層１２は、ＹＳＺ及び希土類元素が添加されたセリア系酸化物の固溶体とＮｉとを含む。固溶体とは、ＹＳＺ及び希土類元素が添加されたセリア系酸化物が互いに溶け合って、全体が均一の固相となっているものをいう。 The intermediate layer 12 is made of a porous material having electronic conductivity and ionic conductivity. Specifically, the intermediate layer 12 includes Ni and a solid solution of ceria-based oxide to which YSZ and a rare earth element are added. A solid solution is one in which YSZ and a ceria-based oxide to which a rare earth element is added are dissolved together to form a uniform solid phase.
　ここで、支持層１１及び水素極１３が還元雰囲気に曝されると、支持層１１及び水素極１３に含まれるＮｉＯは還元されてＮｉとなるため、支持層１１及び水素極１３それぞれに体積変化が生じる。加えて、水素極１３中のＣｅＯ２は還元雰囲気における膨張量が大きいのに対して、支持層１１中のＺｒＯ２は還元雰囲気における膨張量が相対的に小さいため、還元雰囲気では水素極１３と支持層１１の間に膨張量差が生じる。この状況下で燃料電池セル１０の起動及び停止が繰り返されると、水素極１３内に蓄積される応力によってクラックが生じやすい。 Here, when the support layer 11 and the hydrogen electrode 13 are exposed to a reducing atmosphere, the NiO contained in the support layer 11 and the hydrogen electrode 13 is reduced to Ni, so the volume changes in the support layer 11 and the hydrogen electrode 13, respectively. occurs. In addition, CeO 2 in the hydrogen electrode 13 has a large expansion amount in a reducing atmosphere, whereas ZrO 2 in the support layer 11 has a relatively small expansion amount in a reducing atmosphere. A difference in the amount of expansion occurs between the support layers 11. If the fuel cell 10 is repeatedly started and stopped under this condition, cracks are likely to occur due to stress accumulated within the hydrogen electrode 13.
　そこで、本実施形態に係る中間層１２は、支持層１１の構成材料であるＹＳＺと、後述する水素極１３の構成材料である希土類元素が添加されたセリア系酸化物との両方を含有している。この中間層１２が水素極１３と支持層１１の間の膨張量差を緩衝させる緩衝層として機能することによって、支持層１１と水素極１３が直接接続される場合に比べて水素極１３内に応力が蓄積されることを抑制できる。よって、水素極１３にクラックが生じることを抑制できる。 Therefore, the intermediate layer 12 according to the present embodiment contains both YSZ, which is a constituent material of the support layer 11, and a ceria-based oxide added with a rare earth element, which is a constituent material of the hydrogen electrode 13, which will be described later. There is. This intermediate layer 12 functions as a buffer layer that buffers the difference in the amount of expansion between the hydrogen electrode 13 and the support layer 11, so that the inside of the hydrogen electrode 13 is smaller than when the support layer 11 and the hydrogen electrode 13 are directly connected. Accumulation of stress can be suppressed. Therefore, generation of cracks in the hydrogen electrode 13 can be suppressed.
　中間層１２は、支持層１１と水素極１３の間において、ＹＳＺ及び希土類元素が添加されたセリア系酸化物の固溶体が存在する領域である。希土類元素が添加されたセリア系酸化物としては、例えば、ガドリニウムドープセリア（ＧＤＣ）、サマリウムドープセリア（ＳＤＣ）、イットリウムドープセリア（ＹＤＣ）などが挙げられるが、これらには限られない。ＧＤＣとしては、５ｍｏｌ％以上２０ｍｏｌ％以下のＧｄ（ガドリニウム）の酸化物がドープされたＣｅＯ２（セリア）を用いることができる。Ｎｉは、燃料ガスが供給された還元雰囲気では金属Ｎｉとなり、燃料ガスが供給されない酸化雰囲気ではＮｉＯとなる。 The intermediate layer 12 is a region between the support layer 11 and the hydrogen electrode 13 in which a solid solution of ceria-based oxide to which YSZ and a rare earth element are added exists. Examples of ceria-based oxides doped with rare earth elements include, but are not limited to, gadolinium-doped ceria (GDC), samarium-doped ceria (SDC), and yttrium-doped ceria (YDC). As the GDC, CeO 2 (ceria) doped with an oxide of Gd (gadolinium) of 5 mol % or more and 20 mol % or less can be used. Ni becomes metallic Ni in a reducing atmosphere where fuel gas is supplied, and becomes NiO in an oxidizing atmosphere where fuel gas is not supplied.
　中間層１２におけるＹＳＺの含有率は、１５ｍｏｌ％以上３５ｍｏｌ％以下とすることができる。中間層１２における希土類元素が添加されたセリア系酸化物の含有率は、１５ｍｏｌ％以上３５ｍｏｌ％以下とすることができる。中間層１２におけるＮｉの含有率は、ＮｉＯ換算で３５ｍｏｌ％以上６５ｍｏｌ％以下とすることができる。支持層１１におけるＹＳＺ、希土類元素が添加されたセリア系酸化物及びＮｉそれぞれの含有率は、上述した原子濃度プロファイルによるライン分析によって得られる。 The content of YSZ in the intermediate layer 12 can be 15 mol% or more and 35 mol% or less. The content of the ceria-based oxide to which a rare earth element is added in the intermediate layer 12 can be 15 mol% or more and 35 mol% or less. The content of Ni in the intermediate layer 12 can be 35 mol% or more and 65 mol% or less in terms of NiO. The respective contents of YSZ, rare earth element-added ceria-based oxide, and Ni in the support layer 11 are obtained by line analysis using the atomic concentration profile described above.
　中間層１２の厚さは、例えば１μm以上５０μm以下とすることができる。中間層１２の厚さは、２０μｍ以下であることが好ましい。これによって、中間層１２内のイオン伝導パスが切れてしまうことを抑制できるため、燃料電池セル１０の初期性能が低くなることを抑制できる。また、中間層１２の厚さは、３μｍ以上であることが好ましい。これによって、水素極１３にクラックが生じることをより抑制することができる。よって、中間層１２の厚さを３μｍ以上２０μｍ以下とすることによって、燃料電池セル１０の初期性能の確保とクラックの更なる抑制とを両立させることができる。 The thickness of the intermediate layer 12 can be, for example, 1 μm or more and 50 μm or less. The thickness of the intermediate layer 12 is preferably 20 μm or less. As a result, it is possible to prevent the ion conduction path within the intermediate layer 12 from being cut off, and therefore it is possible to prevent the initial performance of the fuel cell 10 from deteriorating. Further, the thickness of the intermediate layer 12 is preferably 3 μm or more. Thereby, it is possible to further suppress the occurrence of cracks in the hydrogen electrode 13. Therefore, by setting the thickness of the intermediate layer 12 to 3 μm or more and 20 μm or less, it is possible to both ensure the initial performance of the fuel cell 10 and further suppress cracks.
　なお、中間層１２の厚さは、厚み方向に沿った中間層１２の断面をＦＥ－ＳＥＭを用いて１０００倍で観察し、観察画像内から無作為に選択した５箇所における中間層１２の厚みを算術平均することによって取得される。厚み方向とは、電解質１４の水素極側表面に垂直な方向である。 The thickness of the intermediate layer 12 is determined by observing a cross section of the intermediate layer 12 along the thickness direction at 1000 times magnification using FE-SEM, and determining the thickness of the intermediate layer 12 at five points randomly selected from the observed image. is obtained by taking the arithmetic mean of The thickness direction is a direction perpendicular to the surface of the electrolyte 14 on the hydrogen electrode side.
　中間層１２の気孔率は、例えば、１０％以上５０％以下とすることができる。 The porosity of the intermediate layer 12 can be, for example, 10% or more and 50% or less.
　［水素極１３］
　水素極１３は、中間層１２上に配置される。水素極１３は、中間層１２と電解質１４の間に配置される。水素極１３には、支持層１１及び中間層１２を介して燃料ガスが供給される。水素極１３では、次の式（１）で表される電極反応が起こる。 [Hydrogen electrode 13]
Hydrogen electrode 13 is placed on intermediate layer 12 . Hydrogen electrode 13 is placed between intermediate layer 12 and electrolyte 14 . Fuel gas is supplied to the hydrogen electrode 13 via the support layer 11 and the intermediate layer 12 . At the hydrogen electrode 13, an electrode reaction expressed by the following formula (1) occurs.
　Ｈ２＋Ｏ２－→Ｈ２Ｏ＋２ｅ－　　　　　…（１） H2 + O2- → H2O +2e -... (1)
　水素極１３は、電子伝導性及びイオン伝導性を有する多孔質材料によって構成される。具体的には、水素極１３は、希土類元素が添加されたセリア系酸化物とＮｉとを含む。希土類元素が添加されたセリア系酸化物としては、例えば、ＧＤＣ、ＳＤＣ、ＹＤＣなどが挙げられるが、これらには限られない。ＧＤＣとしては、５ｍｏｌ％以上２０ｍｏｌ％以下のＧｄ（ガドリニウム）の酸化物がドープされたＣｅＯ２（セリア）を用いることができる。水素極１３に含まれる希土類元素が添加されたセリア系酸化物は、中間層１２に含まれる希土類元素が添加されたセリア系酸化物と同種であってもよいし異種であってもよい。Ｎｉは、燃料ガスが供給された還元雰囲気では金属Ｎｉとなり、燃料ガスが供給されない酸化雰囲気ではＮｉＯとなる。このように、Ｎｉの還元及び酸化に応じて水素極１３は収縮及び膨張するが、上述の通り水素極１３の体積変化が中間層１２において吸収されることによって、水素極１３にクラックが生じることが抑制される。 The hydrogen electrode 13 is made of a porous material having electronic conductivity and ionic conductivity. Specifically, the hydrogen electrode 13 includes a ceria-based oxide to which a rare earth element is added and Ni. Examples of ceria-based oxides doped with rare earth elements include, but are not limited to, GDC, SDC, and YDC. As the GDC, CeO 2 (ceria) doped with an oxide of Gd (gadolinium) of 5 mol % or more and 20 mol % or less can be used. The rare earth element-doped ceria-based oxide contained in the hydrogen electrode 13 may be the same or different from the rare-earth element-added ceria-based oxide contained in the intermediate layer 12 . Ni becomes metallic Ni in a reducing atmosphere where fuel gas is supplied, and becomes NiO in an oxidizing atmosphere where fuel gas is not supplied. In this way, the hydrogen electrode 13 contracts and expands in response to the reduction and oxidation of Ni, but as described above, the change in volume of the hydrogen electrode 13 is absorbed by the intermediate layer 12, which causes cracks to occur in the hydrogen electrode 13. is suppressed.
　水素極１３における希土類元素が添加されたセリア系酸化物の含有率は、３５ｍｏｌ％以上６５ｍｏｌ％以下とすることができる。水素極１３におけるＮｉの含有率は、ＮｉＯ換算で３５ｍｏｌ％以上６５ｍｏｌ％以下とすることができる。水素極１３における希土類元素が添加されたセリア系酸化物及びＮｉそれぞれの含有率は、上述した原子濃度プロファイルによるライン分析によって得られる。 The content of the ceria-based oxide to which rare earth elements are added in the hydrogen electrode 13 can be set to 35 mol% or more and 65 mol% or less. The Ni content in the hydrogen electrode 13 can be 35 mol% or more and 65 mol% or less in terms of NiO. The respective contents of ceria-based oxide to which a rare earth element is added and Ni in the hydrogen electrode 13 are obtained by line analysis using the atomic concentration profile described above.
　水素極１３の気孔率は、例えば、１０％以上５０％以下とすることができる。水素極１３の厚さは、例えば、５μｍ以上０．１ｍｍ以下とすることができる。 The porosity of the hydrogen electrode 13 can be, for example, 10% or more and 50% or less. The thickness of the hydrogen electrode 13 can be, for example, 5 μm or more and 0.1 mm or less.
　［電解質１４］
　電解質１４は、水素極１３上に配置される。電解質１４は、水素極１３と酸素極１６の間に配置される。本実施形態では、燃料電池セル１０が反応防止層１５を備えているため、電解質１４は、水素極１３と反応防止層１５によって挟まれている。 [Electrolyte 14]
Electrolyte 14 is placed on hydrogen electrode 13 . Electrolyte 14 is placed between hydrogen electrode 13 and oxygen electrode 16. In this embodiment, since the fuel cell 10 includes the reaction prevention layer 15, the electrolyte 14 is sandwiched between the hydrogen electrode 13 and the reaction prevention layer 15.
　電解質１４は、イオン伝導性を有し且つ電子伝導性を有さない緻密質材料によって構成される。電解質１４は、例えば、Ｙ２Ｏ３、ＣｅＯ２、Ｓｃ２Ｏ３、Ｙｂ２Ｏ３などで安定化されたＺｒＯ２や、Ｙ２Ｏ３、Ｓｍ２Ｏ３、Ｇｄ２Ｏ３などがドープされたＣｅＯ２によって構成することができる。或いは、電解質１４は、ランタンガレート、又は、ランタンガレートのランタン又はガリウムの一部がストロンチウム、カルシウム、バリウム、マグネシウム、アルミニウム、インジウム、コバルト、鉄、ニッケル、銅などで置換されたランタンガレート型ペロブスカイト構造酸化物によって構成することができる。電解質１４は、１種の電解質材料によって構成されてもよいし、２種以上の電解質材料によって構成されてもよい。 The electrolyte 14 is made of a dense material that has ionic conductivity and no electronic conductivity. The electrolyte 14 is, for example, ZrO 2 stabilized with Y 2 O 3 , CeO 2 , Sc 2 O 3 , Yb 2 O 3 or the like, or doped with Y 2 O 3 , Sm 2 O 3 , Gd 2 O 3 or the like. It can be composed of CeO 2 . Alternatively, the electrolyte 14 is lanthanum gallate, or a lanthanum gallate type perovskite structure in which part of the lanthanum or gallium of the lanthanum gallate is replaced with strontium, calcium, barium, magnesium, aluminum, indium, cobalt, iron, nickel, copper, etc. It can be composed of an oxide. The electrolyte 14 may be composed of one type of electrolyte material, or may be composed of two or more types of electrolyte materials.
　電解質１４の気孔率は、例えば、０％以上７％以下とすることができる。電解質１４の厚さは、例えば、３μｍ以上５０μｍ以下とすることができる。なお、電解質１４は、単層構造であってもよいし、多層構造であってもよい。 The porosity of the electrolyte 14 can be, for example, 0% or more and 7% or less. The thickness of the electrolyte 14 can be, for example, 3 μm or more and 50 μm or less. Note that the electrolyte 14 may have a single layer structure or a multilayer structure.
　［反応防止層１５］
　反応防止層１５は、電解質１４上に配置される。反応防止層１５は、電解質１４と酸素極１６の間に配置される。反応防止層１５は、電解質１４の構成材料と酸素極１６の構成材料とが反応して電気抵抗の大きい反応層が形成されることを抑制するために設けられている。 [Reaction prevention layer 15]
Reaction prevention layer 15 is placed on electrolyte 14 . Reaction prevention layer 15 is arranged between electrolyte 14 and oxygen electrode 16. The reaction prevention layer 15 is provided to prevent the constituent materials of the electrolyte 14 and the constituent materials of the oxygen electrode 16 from reacting to form a reaction layer with high electrical resistance.
　反応防止層１５は、イオン伝導性材料によって構成される。反応防止層１５は、例えばＧｄ、Ｓｍ及びＹ等の希土類元素の酸化物等がドープされたセリアによって構成することができる。 The reaction prevention layer 15 is made of an ion conductive material. The reaction prevention layer 15 can be made of ceria doped with oxides of rare earth elements such as Gd, Sm, and Y, for example.
　反応防止層１５の気孔率は、例えば、０．1％以上５０％以下とすることができる。反応防止層１５の厚さは、例えば、１μｍ以上５０μｍ以下とすることができる。 The porosity of the reaction prevention layer 15 can be, for example, 0.1% or more and 50% or less. The thickness of the reaction prevention layer 15 can be, for example, 1 μm or more and 50 μm or less.
　［酸素極１６］
　酸素極１６は、反応防止層１５上に配置される。酸素極１６には、酸素を含むガス（例えば、空気）が供給される。酸素極１６では、次の式（２）で表される電極反応が起こる。 [Oxygen electrode 16]
Oxygen electrode 16 is placed on reaction prevention layer 15 . The oxygen electrode 16 is supplied with a gas containing oxygen (for example, air). At the oxygen electrode 16, an electrode reaction expressed by the following equation (2) occurs.
　（１／２）・Ｏ２＋２ｅ－→Ｏ２－　　　…（２） (1/2)・O 2 +2e − →O 2 − …(2)
　酸素極１６は、電子伝導性を有する多孔質材料によって構成される。酸素極１６は、例えば、ＬＳＣＦ＝（Ｌａ，Ｓｒ）（Ｃｏ，Ｆｅ）Ｏ３（ランタンストロンチウムコバルトフェライト）、ＬＳＦ＝（Ｌａ，Ｓｒ）ＦｅＯ３（ランタンストロンチウムフェライト）、ＬＮＦ＝Ｌａ（Ｎｉ，Ｆｅ）Ｏ３（ランタンニッケルフェライト）、ＬＳＣ＝（Ｌａ，Ｓｒ）ＣｏＯ３（ランタンストロンチウムコバルタイト）等によって構成することができる。 The oxygen electrode 16 is made of a porous material that has electronic conductivity. The oxygen electrode 16 is made of, for example, LSCF=(La,Sr)(Co,Fe)O 3 (lanthanum strontium cobalt ferrite), LSF=(La,Sr)FeO 3 (lanthanum strontium ferrite), LNF=La(Ni,Fe ) O 3 (lanthanum nickel ferrite), LSC=(La,Sr)CoO 3 (lanthanum strontium cobaltite), or the like.
　酸素極１６の気孔率は、例えば、１０％以上５０％以下とすることができる。酸素極１６の厚さは、例えば、１０μｍ以上１００μｍ以下とすることができる。 The porosity of the oxygen electrode 16 can be, for example, 10% or more and 50% or less. The thickness of the oxygen electrode 16 can be, for example, 10 μm or more and 100 μm or less.
　（実施形態の変形例）
　以上、本発明の実施形態について説明したが、本発明はこれらに限定されるものではなく、本発明の趣旨を逸脱しない限りにおいて種々の変更が可能である。 (Modified example of embodiment)
Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various changes can be made without departing from the spirit of the present invention.
　［変形例１］
　上記実施形態では、燃料電池の一例として、いわゆるアノード支持型の燃料電池セルについて説明したが、電気化学セルはこれに限られない。本発明は、電解質層の両側に水素極と酸素極とが配置された電気化学セルに適用可能である。 [Modification 1]
In the embodiment described above, a so-called anode-supported fuel cell has been described as an example of a fuel cell, but the electrochemical cell is not limited to this. The present invention is applicable to an electrochemical cell in which a hydrogen electrode and an oxygen electrode are arranged on both sides of an electrolyte layer.
　電気化学セルとは、電気エネルギーを化学エネルギーに変えるため、全体的な酸化還元反応から起電力が生じるように一対の電極が配置された素子と、化学エネルギーを電気エネルギーに変えるための素子との総称である。 An electrochemical cell consists of an element with a pair of electrodes arranged so that an electromotive force is generated from the overall redox reaction, and an element that converts chemical energy into electrical energy. It is a generic term.
　電気化学セルとしては、アノード支持型の燃料電池セルのほか、横縞型の燃料電池セル、縦縞型の燃料電池セル、平板型の燃料電池セル、筒型の燃料電池セル、更に、水の電気分解反応を利用して水素の生成を行う電解セルなどが挙げられる。また、上記実施形態では、Ｏ２－（酸素イオン）をキャリアとしたが、ＯＨ－（水酸化物イオン）やプロトンをキャリアとしてもよい。 Electrochemical cells include anode-supported fuel cells, horizontal striped fuel cells, vertical striped fuel cells, flat plate fuel cells, cylindrical fuel cells, and water electrolysis cells. Examples include electrolytic cells that generate hydrogen using reactions. Furthermore, in the above embodiments, O 2 - (oxygen ions) are used as carriers, but OH - (hydroxide ions) or protons may be used as carriers.
　［変形例２］
　上記実施形態において、燃料電池セル１０は、反応防止層１５を備えることとしたが、反応防止層１５を備えていなくてもよい。 [Modification 2]
In the above embodiment, the fuel cell 10 is provided with the reaction prevention layer 15, but the reaction prevention layer 15 may not be provided.
　以下において本発明に係る電解セルの実施例について説明するが、本発明は以下に説明する実施例に限定されるものではない。 Examples of the electrolytic cell according to the present invention will be described below, but the present invention is not limited to the examples described below.
　（実施例１～７の作製）
　以下のようにして、実施例１～７に係る電解セルを作製した。 (Production of Examples 1 to 7)
Electrolytic cells according to Examples 1 to 7 were produced as follows.
　まず、ＹＳＺ粉末、ＮｉＯ粉末、バインダ、造孔剤、可塑剤、分散媒及び溶剤を混合した支持層用スラリーをシート成形することによって、支持層成形体を作製した。 First, a support layer molded body was produced by sheet-molding a support layer slurry containing a mixture of YSZ powder, NiO powder, binder, pore-forming agent, plasticizer, dispersion medium, and solvent.
　次に、ＹＳＺ粉末、ＧＤＣ粉末、ＮｉＯ粉末、バインダ、造孔剤、可塑剤、分散媒及び溶剤を混合することによって調製した中間層用ペーストを支持層成形体上に印刷することによって、中間層成形体を形成した。この際、中間層用ペーストの印刷厚みを変更することによって、表１に示すように、実施例１～７それぞれの中間層の厚みを調整した。 Next, an intermediate layer paste prepared by mixing YSZ powder, GDC powder, NiO powder, binder, pore-forming agent, plasticizer, dispersion medium, and solvent is printed on the support layer molded body. A molded body was formed. At this time, the thickness of each intermediate layer of Examples 1 to 7 was adjusted as shown in Table 1 by changing the printing thickness of the intermediate layer paste.
　次に、ＧＤＣ粉末、ＮｉＯ粉末、バインダ、造孔剤、可塑剤、分散媒及び溶剤を混合することによって調製した水素極用ペーストを中間層成形体上に印刷することによって、水素極成形体を形成した。 Next, a hydrogen electrode paste prepared by mixing GDC powder, NiO powder, binder, pore-forming agent, plasticizer, dispersion medium, and solvent is printed on the intermediate layer molded body to form a hydrogen electrode molded body. Formed.
　次に、ＹＳＺ粉末、バインダ、可塑剤、分散媒及び溶剤を混合することによって調製した電解質用ペーストを水素極成形体上に印刷することによって、電解質成形体を形成した。 Next, an electrolyte molded body was formed by printing an electrolyte paste prepared by mixing YSZ powder, a binder, a plasticizer, a dispersion medium, and a solvent onto the hydrogen electrode molded body.
　次に、ＧＤＣ粉末、バインダ、及び溶剤を混合することによって調製した反応防止層用ペーストを電解質成形体上に印刷することによって、反応防止層成形体を形成した。 Next, a reaction prevention layer molded body was formed by printing a reaction prevention layer paste prepared by mixing GDC powder, a binder, and a solvent onto the electrolyte molded body.
　支持層成形体、中間層成形体、水素極成形体、電解質成形体及び反応防止層成形体の積層体を焼成（１３００℃、５時間）することによって、支持層、中間層、水素極、電解質及び反応防止層からなる焼成体を作製した。 The support layer, the intermediate layer, the hydrogen electrode, and the electrolyte are formed by firing (1300°C, 5 hours) the laminate of the support layer molded body, the intermediate layer molded body, the hydrogen electrode molded body, the electrolyte molded body, and the reaction prevention layer molded body. A fired body consisting of a reaction prevention layer and a reaction prevention layer was produced.
　ＬＳＣＦ粉末、バインダ及び溶剤を混合することによって調製した酸素極用ペーストを反応防止層上に印刷することによって、酸素極成形体を形成した。 An oxygen electrode molded body was formed by printing an oxygen electrode paste prepared by mixing LSCF powder, a binder, and a solvent onto the reaction prevention layer.
　次に、酸素極成形体を焼成（１０５０℃、２時間）することによって、実施例１～７に係る電解セルを得た。 Next, the oxygen electrode molded body was fired (1050°C, 2 hours) to obtain electrolytic cells according to Examples 1 to 7.
　（比較例１の作製）
　中間層を形成しなかったこと以外は上記実施例１～７と同じ工程により比較例１に係る電解セルを作製した。 (Preparation of Comparative Example 1)
An electrolytic cell according to Comparative Example 1 was produced using the same steps as in Examples 1 to 7 above, except that no intermediate layer was formed.
　（熱サイクル試験）
　実施例１～７及び比較例１に係る電解セルにおいて、１回目の熱サイクル試験を実施した。具体的には、水素極にＡｒガス及び水素ガス（Ａｒガスに対して４％）を供給しながら、常温から７５０℃まで２時間で昇温させた後に７５０℃から常温まで４時間で降温させる工程を１サイクルとして１０回繰り返した。 (Heat cycle test)
A first thermal cycle test was conducted on the electrolytic cells according to Examples 1 to 7 and Comparative Example 1. Specifically, while supplying Ar gas and hydrogen gas (4% relative to Ar gas) to the hydrogen electrode, the temperature is raised from room temperature to 750°C in 2 hours, and then the temperature is lowered from 750°C to room temperature in 4 hours. The process was repeated 10 times as one cycle.
　その後、水素極の断面をＦＥ－ＳＥＭ（電界放出形走査電子顕微鏡）で観察してクラックの有無を確認した。 Thereafter, the cross section of the hydrogen electrode was observed using an FE-SEM (field emission scanning electron microscope) to confirm the presence or absence of cracks.
　続いて、実施例１～７及び比較例１に係る電解セルにおいて、２回目の熱サイクル試験を実施した。具体的には、水素極にＡｒガス及び水素ガス（Ａｒガスに対して４％）を供給しながら、常温から８５０℃まで２時間で昇温させた後に８５０℃から常温まで４時間で降温させる工程を１サイクルとして１０回繰り返した。 Subsequently, a second thermal cycle test was conducted on the electrolytic cells according to Examples 1 to 7 and Comparative Example 1. Specifically, while supplying Ar gas and hydrogen gas (4% relative to Ar gas) to the hydrogen electrode, the temperature is raised from room temperature to 850°C in 2 hours, and then the temperature is lowered from 850°C to room temperature in 4 hours. The process was repeated 10 times as one cycle.
　その後、水素極の断面をＦＥ－ＳＥＭで観察してクラックの有無を確認した。 Thereafter, the cross section of the hydrogen electrode was observed using FE-SEM to confirm the presence or absence of cracks.
　表１では、１回目の熱サイクル試験でクラックが発生したものを「×」、２回目の熱サイクル試験で初めてクラックが発生したものを「〇」、２回目の熱サイクル試験でクラックが発生しなかったものを「◎」と評価した。 In Table 1, "x" indicates that cracks occurred in the first thermal cycle test, "○" indicates that cracks occurred for the first time in the second heat cycle test, and "○" indicates that cracks occurred in the second heat cycle test. Items that were not included were evaluated as "◎".
　（初期性能評価試験）
　実施例１～７及び比較例１に係る電解セルにおいて、初期性能評価試験を実施した。具体的には、水素極に水蒸気及び水素ガスの混合ガス（混合比は５０：５０）を供給するとともに酸素極に空気を供給しながら０．５Ａ／ｃｍ２の電流値を掃引した際の電解電圧を測定した。 (Initial performance evaluation test)
An initial performance evaluation test was conducted on the electrolytic cells according to Examples 1 to 7 and Comparative Example 1. Specifically, electrolysis occurs when a current value of 0.5 A/cm 2 is swept while supplying a mixed gas of water vapor and hydrogen gas (mixing ratio is 50:50) to the hydrogen electrode and supplying air to the oxygen electrode. The voltage was measured.
　そして、比較例１の電解電圧に対する実施例１～７の電解電圧の増大率を算出した。表１では、電解電圧の増大率が１％未満であったものを「〇」と評価し、電解電圧の増大率が１％以上であったものを「△」と評価した。
Figure JPOXMLDOC01-appb-T000001
   Then, the increase rate of the electrolysis voltage in Examples 1 to 7 with respect to the electrolysis voltage in Comparative Example 1 was calculated. In Table 1, those in which the rate of increase in electrolytic voltage was less than 1% were evaluated as "O", and those in which the rate of increase in electrolytic voltage was 1% or more were evaluated as "△".
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、支持層と水素極の間に中間層を設けた実施例１～７では、水素極にクラックが発生することを抑制できた。このような結果が得られたのは、支持層の構成材料であるＹＳＺと水素極の構成材料である希土類元素が添加されたセリア系酸化物との両方を中間層が含有していることによって、熱サイクルにおける水素極と支持層の膨張量差を中間層において緩衝させることができたためである。 As shown in Table 1, in Examples 1 to 7 in which the intermediate layer was provided between the support layer and the hydrogen electrode, it was possible to suppress the occurrence of cracks in the hydrogen electrode. This result was obtained because the intermediate layer contains both YSZ, which is the constituent material of the support layer, and ceria-based oxide added with rare earth elements, which is the constituent material of the hydrogen electrode. This is because the difference in the amount of expansion between the hydrogen electrode and the support layer during thermal cycling could be buffered in the intermediate layer.
　また、中間層の厚さを２０μｍ以下とした実施例１～６では、実施例７に比べて初期性能が低くなることを抑制できた。このような結果が得られたのは、中間層内のイオン伝導パスが切れてしまうことを抑制できたためである。 Furthermore, in Examples 1 to 6 in which the thickness of the intermediate layer was 20 μm or less, it was possible to suppress the initial performance from becoming lower than in Example 7. This result was obtained because the ion conduction path within the intermediate layer was prevented from being cut.
　さらに、中間層の厚さを３μｍ以上とした実施例２～７では、実施例１に比べて、水素極にクラックが発生することを更に抑制できた。 Furthermore, in Examples 2 to 7 in which the thickness of the intermediate layer was 3 μm or more, the generation of cracks in the hydrogen electrode was further suppressed compared to Example 1.
１０　　燃料電池セル
１１　　支持層
１２　　中間層
１３　　水素極
１４　　電解質
１５　　反応防止層
１６　　酸素極 10 Fuel cell 11 Support layer 12 Intermediate layer 13 Hydrogen electrode 14 Electrolyte 15 Reaction prevention layer 16 Oxygen electrode

Claims (3)

  1. 　支持層と、
    　前記支持層上に配置される中間層と、
    　前記中間層上に配置される水素極と、
    　酸素極と、
    　前記水素極及び前記酸素極の間に配置される電解質と、
    を備え、
    　前記支持層は、イットリア安定化ジルコニアと、ニッケルと含み、
    　前記水素極は、希土類元素が添加されたセリア系酸化物と、ニッケルとを含み、
    　前記中間層は、イットリア安定化ジルコニア及び希土類元素が添加されたセリア系酸化物の固溶体と、ニッケルとを含む、
    電気化学セル。     a support layer;
    an intermediate layer disposed on the support layer;
    a hydrogen electrode disposed on the intermediate layer;
    an oxygen electrode,
    an electrolyte disposed between the hydrogen electrode and the oxygen electrode;
    Equipped with
    the support layer includes yttria-stabilized zirconia and nickel;
    The hydrogen electrode includes a ceria-based oxide to which a rare earth element is added and nickel,
    The intermediate layer includes yttria-stabilized zirconia and a solid solution of ceria-based oxide added with a rare earth element, and nickel.
    electrochemical cell.
  2. 　前記中間層の厚みは、２０μｍ以下である、
    請求項１に記載の電気化学セル。     The thickness of the intermediate layer is 20 μm or less,
    An electrochemical cell according to claim 1.
  3. 　前記中間層の厚みは、３μｍ以上である、
    請求項１又は２に記載の電気化学セル。     The thickness of the intermediate layer is 3 μm or more,
    The electrochemical cell according to claim 1 or 2.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012520553A (en) * 2009-03-16 2012-09-06 コリア・インスティテュート・オブ・サイエンス・アンド・テクノロジー A fuel electrode-supported solid oxide fuel cell including a nanoporous layer having an inclined pore structure and a method for manufacturing the same
JP2017139078A (en) * 2016-02-02 2017-08-10 株式会社Ｓｏｋｅｎ Solid oxide fuel battery cell
JP2021034374A (en) * 2019-08-19 2021-03-01 日本碍子株式会社 Fuel battery cell and cell stack device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012520553A (en) * 2009-03-16 2012-09-06 コリア・インスティテュート・オブ・サイエンス・アンド・テクノロジー A fuel electrode-supported solid oxide fuel cell including a nanoporous layer having an inclined pore structure and a method for manufacturing the same
JP2017139078A (en) * 2016-02-02 2017-08-10 株式会社Ｓｏｋｅｎ Solid oxide fuel battery cell
JP2021034374A (en) * 2019-08-19 2021-03-01 日本碍子株式会社 Fuel battery cell and cell stack device

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