WO2023195246A1 - Electrochemical cell - Google Patents

Electrochemical cell Download PDF

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Publication number
WO2023195246A1
WO2023195246A1 PCT/JP2023/005685 JP2023005685W WO2023195246A1 WO 2023195246 A1 WO2023195246 A1 WO 2023195246A1 JP 2023005685 W JP2023005685 W JP 2023005685W WO 2023195246 A1 WO2023195246 A1 WO 2023195246A1
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Prior art keywords
hydrogen electrode
electrode
electrolyte
current collector
ionic conductivity
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PCT/JP2023/005685
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French (fr)
Japanese (ja)
Inventor
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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Priority to JP2024514170A priority Critical patent/JPWO2023195246A1/ja
Publication of WO2023195246A1 publication Critical patent/WO2023195246A1/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
    • C25B11/047—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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • 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
    • 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.
  • a fuel cell is known as an example of an electrochemical cell (see, for example, Patent Document 1).
  • a fuel cell includes a hydrogen electrode, an oxygen electrode, and an electrolyte disposed between the hydrogen electrode and the oxygen electrode.
  • the hydrogen electrode is composed of nickel (Ni), which primarily functions as an electron conductor, and ceria-based oxide containing a solid solution of a rare earth element, which primarily functions as an oxygen ion conductor.
  • Gadolinium-doped ceria is typical of ceria-based oxides containing rare earth elements in solid solution.
  • the hydrogen electrode will deteriorate due to the adhesion of the poisonous substance.
  • a poisonous substance for example, silicon, etc.
  • An object of the present invention is to provide an electrochemical cell that can suppress deterioration of a hydrogen electrode.
  • the electrochemical cell according to the present invention includes a hydrogen electrode containing an ion conductive material containing cerium, an oxygen electrode, and an electrolyte disposed between the hydrogen electrode and the oxygen electrode.
  • the hydrogen electrode has a first portion that is within 8 ⁇ m from the surface opposite the electrolyte and a second portion that is more than 8 ⁇ m from the surface.
  • the ionic conductivity of the first portion is lower than the ionic conductivity of the second portion.
  • FIG. 1 is a perspective view of a fuel cell.
  • FIG. 2 is a cross-sectional view of the fuel cell.
  • FIG. 3 is a partially enlarged view of FIG. 2.
  • FIG. 1 is a perspective view of a fuel cell 10.
  • FIG. 2 is a cross-sectional view of the fuel cell 10 taken along a gas flow path 21, which will be described later.
  • the fuel cell 10 includes a support substrate 20 and a plurality of power generation element sections 30.
  • the support substrate 20 is formed into a flat plate shape.
  • the dimension in the length direction (x-axis direction) is longer than the dimension in the width direction (y-axis direction), but the dimension in the width direction may be longer than the length direction. .
  • the support substrate 20 has a first main surface S1 and a second main surface T1.
  • the first main surface S1 and the second main surface T1 face oppositely to each other in the thickness direction (z-axis direction) of the support substrate 20.
  • the first main surface S1 and the second main surface T1 support each power generation element section 30.
  • the support substrate 20 is made of a porous material that does not have electronic conductivity.
  • the support substrate 20 is made of, for example, CSZ (calcia stabilized zirconia).
  • the support substrate 20 may be composed of NiO (nickel oxide) and YSZ (yttria stabilized zirconia), or may be composed of NiO (nickel oxide) and Y 2 O 3 (yttria).
  • the porosity of the support substrate 20 can be, for example, 20% or more and 60% 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).
  • a plurality of gas channels 21 are formed inside the support substrate 20.
  • Each gas flow path 21 is supplied with fuel gas such as hydrogen gas.
  • each gas flow path 21 extends in the length direction (x-axis direction) within the support substrate 20.
  • Each gas flow path 21 penetrates the support substrate 20. It is preferable that each gas flow path 21 is arranged at substantially equal intervals.
  • the support substrate 20 is covered with a dense layer 22.
  • the dense layer 22 covers a region of the surface of the support substrate 20 that is not covered by each power generation element section 30 .
  • the dense layer 22 suppresses the gas diffused within the support substrate 20 from being discharged to the outside.
  • the dense layer 22 is made of, for example, MgO (magnesium oxide), CaZrO 3 (calcium zirconate), Y 2 O 3 (yttria), MgAl 2 O 4 (magnesia alumina spinel), CSZ (calcia stabilized zirconia), YSZ (8YSZ).
  • the dense layer 22 is denser than the support substrate 20.
  • the porosity of the dense layer 22 can be, for example, 0% or more and 7% or less.
  • each power generation element section 30 is supported by the first main surface S1 or the second main surface T1 of the support substrate 20.
  • the number of power generation element sections 30 arranged on the first main surface S1 and the number of power generation element sections 30 arranged on the second main surface T1 may be the same or different.
  • the sizes of the power generating element sections 30 may be the same or different.
  • the power generation element sections 30 are arranged at intervals along the length direction (x-axis direction) in which the gas flow path 21 extends. Each power generating element section 30 is electrically connected to each other in series.
  • the power generation element section 30 includes a first current collecting section 1 , a hydrogen electrode 2 , an electrolyte 3 , a reaction prevention layer 4 , an oxygen electrode 5 , a second current collecting section 6 , and an interconnector 7 .
  • the first current collector 1 is arranged within the recess 23 of the support substrate 20.
  • the first current collector 1 has a first recess 11 and a second recess 12 .
  • the hydrogen electrode 2 is placed inside the first recess 11 .
  • the interconnector 7 is arranged within the second recess 12 .
  • the first current collector 1 is made of a porous material having electron conductivity.
  • the first current collector 1 can be made of, for example, NiO (nickel oxide) and Y 2 O 3 (yttria).
  • the first current collector 1 may be composed of NiO (nickel oxide) and 8YSZ (yttria stabilized zirconia), or may be composed of NiO (nickel oxide) and CSZ (calcia stabilized zirconia). Good too.
  • the porosity of the first current collector 1 can be, for example, 10% or more and 50% or less.
  • the thickness of the first current collector 1 can be, for example, 50 ⁇ m or more and 500 ⁇ m or less.
  • Hydrogen electrode 2 is arranged within first recess 11 of first current collector 1 . Fuel gas is supplied to the hydrogen electrode 2 from the gas flow path 21 via the support substrate 20 and the first current collector 1 . At the hydrogen electrode 2, an electrode reaction expressed by the following formula (1) occurs. H2 + O2- ⁇ H2O +2e -... (1)
  • the hydrogen electrode 2 is made of a porous material that has electronic conductivity and ionic conductivity. Hydrogen electrode 2 contains an ion conductive material containing cerium. The porosity of the hydrogen electrode 2 can be, for example, 10% or more and 50% or less. The thickness of the hydrogen electrode 2 can be, for example, more than 8 ⁇ m and less than 30 ⁇ m. The configuration of the hydrogen electrode 2 will be described later.
  • the electrolyte 3 is arranged to cover the hydrogen electrode 2. Both ends of the electrolyte 3 in the length direction (x-axis direction) are connected to an interconnector 7 .
  • the electrolyte 3 is made of a dense material that has ionic conductivity and no electronic conductivity.
  • the electrolyte 3 is composed of, for example, YSZ (8YSZ), LSGM (lanthanum gallate), or the like.
  • the electrolyte 3 is denser than the hydrogen electrode 2.
  • the porosity of the electrolyte 3 can be, for example, 0% or more and 7% or less.
  • the thickness of the electrolyte 3 can be, for example, 3 ⁇ m or more and 50 ⁇ m or less.
  • Reaction prevention layer 4 is arranged on electrolyte 3 .
  • the reaction prevention layer 4 is arranged at a position corresponding to the hydrogen electrode 2 with the electrolyte 3 interposed therebetween.
  • the reaction prevention layer 4 is provided to prevent the constituent materials of the electrolyte 3 and the constituent materials of the oxygen electrode 5 from reacting to form a reaction layer with high electrical resistance.
  • the reaction prevention layer 4 can be made of an ion conductive material.
  • the porosity of the reaction prevention layer 4 can be, for example, 0.1% or more and 50% or less.
  • the thickness of the reaction prevention layer 4 can be, for example, 1 ⁇ m or more and 50 ⁇ m or less.
  • Oxygen electrode 5 is placed on reaction prevention layer 4 .
  • Oxygen-containing gas for example, air
  • Oxygen-containing gas for example, air
  • an electrode reaction expressed by the following equation (2) occurs. (1/2) ⁇ O 2 +2e ⁇ ⁇ O 2 ⁇ ...(2)
  • the oxygen electrode 5 is made of a porous material having electronic conductivity.
  • the porosity of the oxygen electrode 5 can be, for example, 10% or more and 50% or less.
  • the thickness of the oxygen electrode 5 can be, for example, 10 ⁇ m or more and 100 ⁇ m or less.
  • the second current collector 6 is connected to the oxygen electrode 5 and the interconnector 7.
  • the second current collector 6 is made of a porous material having electron conductivity.
  • the second current collector 6 may or may not have oxygen ion conductivity.
  • the second current collector 6 can be made of, for example, LSCF, LSC, Ag (silver), Ag-Pd (silver-palladium alloy), or the like.
  • the porosity of the second current collector 6 can be, for example, 25% or more and 50% or less.
  • the thickness of the second current collector 6 can be, for example, 50 ⁇ m or more and 500 ⁇ m or less.
  • the interconnector 7 is arranged within the second recess 12 of the first current collector 1 . Both ends of the interconnector 7 in the length direction (x-axis direction) are connected to the electrolyte 3 .
  • the interconnector 7 is made of a dense material that has electronic conductivity.
  • the interconnector 7 can be made of, for example, LaCrO 3 (lanthanum chromite), (Sr,La)TiO 3 (strontium titanate), or the like.
  • the porosity of the interconnector 7 can be, for example, 0% or more and 7% or less.
  • the thickness of the interconnector 7 can be, for example, 10 ⁇ m or more and 100 ⁇ m or less.
  • FIG. 3 is a partially enlarged view of FIG. 2.
  • the hydrogen electrode 2 has a first portion 101 and a second portion 102.
  • the first portion 101 is a region of the hydrogen electrode 2 on the side opposite to the electrolyte 3. Specifically, the first portion 101 is a region within 8 ⁇ m from the surface S2 of the hydrogen electrode 2 on the side opposite to the electrolyte 3. Therefore, the thickness of the first portion 101 is 8 ⁇ m. In this embodiment, the first portion 101 is connected to the first current collector 1 .
  • the surface S2 of the hydrogen electrode 2 (that is, the interface between the first current collector 1 and the hydrogen electrode 2) is specified by a line where the content of Ce (cerium) is 3%.
  • the Ce content is obtained by line analysis using an atomic concentration profile, which will be described later.
  • the second portion 102 is a region of the hydrogen electrode 2 on the electrolyte 3 side. Specifically, the second portion 102 is a region of the hydrogen electrode 2 that is more than 8 ⁇ m from the surface S2. That is, the second portion 102 is a region of the hydrogen electrode 2 excluding the first portion 101. The second portion 102 is integrally formed with the first portion 101. In this embodiment, the second portion 102 is connected to the electrolyte 3.
  • the ionic conductivity of the first portion 101 is lower than the ionic conductivity of the second portion 102. That is, the electrode reaction resistance of the first portion 101 is greater than the electrode reaction resistance of the second portion 102. Therefore, during operation of the fuel cell 10, the first portion 101 becomes higher in temperature than the second portion 102 due to the heat of reaction. Therefore, when the fuel gas supplied to the hydrogen electrode 2 contains a poisonous substance (for example, silicon, etc.), the poisonous substance can be efficiently adsorbed onto the first portion 101.
  • a poisonous substance for example, silicon, etc.
  • the ionic conductivity of the first portion 101 is measured as follows. First, in the cross section of the hydrogen electrode 2 along the thickness direction (z-axis direction), the first portion 101 is defined as a region within 8 ⁇ m from the surface S2 on the opposite side to the electrolyte 3. Next, by obtaining elemental mapping of the first portion 101 using an Electron Probe Micro Analyzer (EPMA), the composition of the first portion 101 and the content rate of each composition are specified. Next, pellets to be measured are prepared by mixing the specified composition at the specified content rate and firing (1300° C. for 5 hours). Next, two terminal attachment pellets made of YSZ and fired (1300° C. for 5 hours) are prepared.
  • EPMA Electron Probe Micro Analyzer
  • the pellet to be measured is sandwiched between two pellets for terminal attachment, and the current wire is bonded to the pellet for terminal attachment with platinum paste, and the potential wire is bonded to the pellet to be measured using platinum paste.
  • the ionic conductivity of the pellet to be measured is measured using a four-terminal method. The ionic conductivity of the pellet to be measured thus measured is the ionic conductivity of the first portion 101.
  • the ionic conductivity of the second portion 102 is measured in the same way as the ionic conductivity of the first portion 101.
  • the first portion 101 and the second portion 102 each contain an ion conductive material containing Ce (cerium) and Ni (nickel).
  • the ionic conductivity of the ion conductive material contained in the first portion 101 may be lower than the ionic conductivity of the ion conductive material contained in the second portion 102.
  • the ion conductive material contained in the first portion 101 is a solid solution of Y 2 O 3 (yttria), CeO 2 (ceria), and Gd 2 O 3 (gadria) (hereinafter referred to as "Y(Ce, Gd) solid solution”). ), and a solid solution of Y 2 O 3 , CeO 2 and Sm 2 O 3 (Samaria) (hereinafter referred to as "Y(Ce,Sm) solid solution”).
  • Y(Ce, Gd) solid solution a solid solution of Y 2 O 3 , CeO 2 and Sm 2 O 3 (Samaria)
  • a Y (Ce, Gd) solid solution is suitable as the ion conductive material contained in the first portion 101.
  • the Y (Ce, Gd) solid solution refers to one in which Y 2 O 3 , CeO 2 and Gd 2 O 3 are dissolved together to form a uniform solid phase.
  • the ion conductive material contained in the second portion 102 includes ceria-based oxide to which a rare earth element is added.
  • a ceria-based oxide to which a rare earth element is added is suitable.
  • 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).
  • 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.
  • the ionic conductivity of the first portion 101 can be adjusted by the composition of the ion conductive material contained in the first portion 101 and the content rate of the ion conductive material.
  • the content of the ion conductive material containing Ce in the first portion 101 can be 35 mol% or more and 65 mol% or less.
  • the ionic conductivity of the second portion 102 can be adjusted by the composition of the ion conductive material contained in the second portion 102 and the content rate of the ion conductive material.
  • the content of the ion conductive material containing Ce in the second portion 102 can be 35 mol% or more and 65 mol% or less.
  • the content of the ion conductive material containing Ce in the first portion 101 and the second portion 102 is obtained by line analysis using an atomic concentration profile, that is, elemental mapping using EPMA. Specifically, concentration distribution data of each element is obtained by performing line analysis in the z-axis direction using EPMA in a cross section along the thickness direction (z-axis direction in FIG. 3).
  • EPMA is a concept that includes EDS (Energy Dispersive x-ray Spectroscopy).
  • the Ni content in the first portion 101 can be 35 mol% or more and 65 mol% or less.
  • the Ni content in the second portion 102 can be 35 mol% or more and 65 mol% or less.
  • Ni content in the first portion 101 and the second portion 102 is obtained by line analysis using the atomic concentration profile described above.
  • Ni is preferably present as metal Ni in a reducing atmosphere supplied with fuel gas, but may be present as NiO when no fuel gas is supplied.
  • 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 vertical striped fuel cells, flat plate fuel cells, cylindrical fuel cells, and hydrogen generation cells that utilize the electrolysis reaction of water.
  • An example is an electrolytic cell that performs this.
  • O 2 - (oxygen ions) are used as carriers, but OH - (hydroxide ions) or protons may be used as carriers.
  • the power generation element section 30 is provided with the reaction prevention layer 4, but the reaction prevention layer 4 may not be provided.
  • Fuel cell 20 Support substrate 30 Power generation element section 1 First current collecting section 2 Hydrogen electrode 101 First section 102 Second section 3 Electrolyte 4 Reaction prevention layer 5 Oxygen electrode 6 Second current collecting section 7 Interconnector

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Abstract

In the present invention, a fuel battery cell (10) comprises: a hydrogen electrode (2) containing an ion-conducting material that includes cerium; an oxygen electrode (5); and an electrolyte (3). The hydrogen electrode (2) has a first portion (101) that is within 8 μm from a surface (S2) on the side away from the electrolyte (3), and a second portion (102) that is greater than 8 μm from the surface (S2). The ion conductivity of the first portion (101) is lower than the ion conductivity of the second portion (102).

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燃料電池が知られている（例えば、特許文献１参照）。燃料電池は、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。水素極は、電子伝導体として主に機能するニッケル（Ｎｉ）と、酸素イオン伝導体として主に機能する希土類元素が固溶したセリア系酸化物とによって構成される。希土類元素が固溶したセリア系酸化物としては、ガドリニウムドープセリアが代表的である。 A fuel cell is known as an example of an electrochemical cell (see, for example, Patent Document 1). A fuel cell includes a hydrogen electrode, an oxygen electrode, and an electrolyte disposed between the hydrogen electrode and the oxygen electrode. The hydrogen electrode is composed of nickel (Ni), which primarily functions as an electron conductor, and ceria-based oxide containing a solid solution of a rare earth element, which primarily functions as an oxygen ion conductor. Gadolinium-doped ceria is typical of ceria-based oxides containing rare earth elements in solid solution.
特開２０１３－２４１６４４号公報JP2013-241644A
　水素極に供給されるガスに被毒物質（例えば、シリコンなど）が含まれている場合、被毒物質の付着によって水素極が劣化してしまう。 If the gas supplied to the hydrogen electrode contains a poisonous substance (for example, silicon, etc.), the hydrogen electrode will deteriorate due to the adhesion of the poisonous substance.
　本発明の課題は、水素極の劣化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 deterioration of a hydrogen electrode.
　本発明に係る電気化学セルは、セリウムを含むイオン伝導性材料を含有する水素極と、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。水素極は、電解質と反対側の表面から８μｍ以内の第１部分と、表面から８μｍ超の第２部分とを有する。第１部分のイオン伝導度は、第２部分のイオン伝導度より低い。 The electrochemical cell according to the present invention includes a hydrogen electrode containing an ion conductive material containing cerium, an oxygen electrode, and an electrolyte disposed between the hydrogen electrode and the oxygen electrode. The hydrogen electrode has a first portion that is within 8 μm from the surface opposite the electrolyte and a second portion that is more than 8 μm from the surface. The ionic conductivity of the first portion is lower than the ionic conductivity of the second portion.
　本発明によれば、水素極の劣化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 deterioration of a hydrogen electrode.
図１は、燃料電池セルの斜視図である。FIG. 1 is a perspective view of a fuel cell. 図２は、燃料電池セルの断面図である。FIG. 2 is a cross-sectional view of the fuel cell. 図３は、図２の部分拡大図である。FIG. 3 is a partially enlarged view of FIG. 2.
　（燃料電池セル１０）
　電気化学セルの一例として燃料電池セル１０について説明する。図１は、燃料電池セル１０の斜視図である。図２は、後述するガス流路２１に沿って切断した燃料電池セル１０の断面図である。 (Fuel cell cell 10)
A fuel cell 10 will be described as an example of an electrochemical cell. FIG. 1 is a perspective view of a fuel cell 10. FIG. 2 is a cross-sectional view of the fuel cell 10 taken along a gas flow path 21, which will be described later.
　図１及び図２に示すように、燃料電池セル１０は、支持基板２０及び複数の発電素子部３０を備える。 As shown in FIGS. 1 and 2, the fuel cell 10 includes a support substrate 20 and a plurality of power generation element sections 30.
　［支持基板２０］
　図１に示すように、支持基板２０は、扁平な板状に形成される。本実施形態に係る支持基板２０では、長さ方向（ｘ軸方向）の寸法が、幅方向（ｙ軸方向）の寸法より長いが、長さ方向より幅方向の寸法の方が長くてもよい。 [Support board 20]
As shown in FIG. 1, the support substrate 20 is formed into a flat plate shape. In the support substrate 20 according to this embodiment, the dimension in the length direction (x-axis direction) is longer than the dimension in the width direction (y-axis direction), but the dimension in the width direction may be longer than the length direction. .
　図２に示すように、支持基板２０は、第１主面Ｓ１と、第２主面Ｔ１とを有する。第１主面Ｓ１と第２主面Ｔ１とは、支持基板２０の厚さ方向（ｚ軸方向）において互いに反対を向いている。第１主面Ｓ１及び第２主面Ｔ１は、各発電素子部３０を支持する。 As shown in FIG. 2, the support substrate 20 has a first main surface S1 and a second main surface T1. The first main surface S1 and the second main surface T1 face oppositely to each other in the thickness direction (z-axis direction) of the support substrate 20. The first main surface S1 and the second main surface T1 support each power generation element section 30.
　支持基板２０は、電子伝導性を有さない多孔質材料によって構成される。支持基板２０は、例えば、ＣＳＺ（カルシア安定化ジルコニア）によって構成される。或いは、支持基板２０は、ＮｉＯ（酸化ニッケル）とＹＳＺ（イットリア安定化ジルコニア）とによって構成されてもよいし、ＮｉＯ（酸化ニッケル）とＹ２Ｏ３（イットリア）とによって構成されてもよいし、ＭｇＯ（酸化マグネシウム）とＭｇＡｌ２Ｏ４（マグネシアアルミナスピネル）とによって構成されてもよい。支持基板２０の気孔率は、例えば、２０％以上６０％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。 The support substrate 20 is made of a porous material that does not have electronic conductivity. The support substrate 20 is made of, for example, CSZ (calcia stabilized zirconia). Alternatively, the support substrate 20 may be composed of NiO (nickel oxide) and YSZ (yttria stabilized zirconia), or may be composed of NiO (nickel oxide) and Y 2 O 3 (yttria). , MgO (magnesium oxide) and MgAl 2 O 4 (magnesia alumina spinel). The porosity of the support substrate 20 can be, for example, 20% or more and 60% 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).
　支持基板２０の内部には、複数のガス流路２１が形成されている。各ガス流路２１には、水素ガスなどの燃料ガスが供給される。本実施形態において、各ガス流路２１は、支持基板２０内を長さ方向（ｘ軸方向）に延びる。各ガス流路２１は、支持基板２０を貫通する。各ガス流路２１は、実質的に等間隔に配置されることが好ましい。 A plurality of gas channels 21 are formed inside the support substrate 20. Each gas flow path 21 is supplied with fuel gas such as hydrogen gas. In this embodiment, each gas flow path 21 extends in the length direction (x-axis direction) within the support substrate 20. Each gas flow path 21 penetrates the support substrate 20. It is preferable that each gas flow path 21 is arranged at substantially equal intervals.
　図１に示すように、支持基板２０は、緻密層２２によって覆われている。緻密層２２は、支持基板２０の表面のうち各発電素子部３０によって覆われていない領域を覆う。緻密層２２は、支持基板２０内に拡散されたガスが外部に排出されることを抑制する。緻密層２２は、例えば、ＭｇＯ（酸化マグネシウム）、ＣａＺｒＯ３（カルシウムジルコネート）、Y２O３（イットリア）、ＭｇＡｌ２O４（マグネシアアルミナスピネル）ＣＳＺ（カルシア安定化ジルコニア）、ＹＳＺ（８ＹＳＺ）（イットリア安定化ジルコニア）、ＬＳＧＭ（ランタンガレート）、ＧＤＣ（ガドリニウムドープセリア）又はＬａＣｒＯ３（ランタンクロマイト）などによって構成される。緻密層２２は、支持基板２０よりも緻密である。緻密層２２の気孔率は、例えば、０％以上７％以下とすることができる。 As shown in FIG. 1, the support substrate 20 is covered with a dense layer 22. The dense layer 22 covers a region of the surface of the support substrate 20 that is not covered by each power generation element section 30 . The dense layer 22 suppresses the gas diffused within the support substrate 20 from being discharged to the outside. The dense layer 22 is made of, for example, MgO (magnesium oxide), CaZrO 3 (calcium zirconate), Y 2 O 3 (yttria), MgAl 2 O 4 (magnesia alumina spinel), CSZ (calcia stabilized zirconia), YSZ (8YSZ). (yttria-stabilized zirconia), LSGM (lanthanum gallate), GDC (gadolinium-doped ceria), or LaCrO 3 (lanthanum chromite). The dense layer 22 is denser than the support substrate 20. The porosity of the dense layer 22 can be, for example, 0% or more and 7% or less.
　［発電素子部３０］
　図１に示すように、各発電素子部３０は、支持基板２０の第１主面Ｓ１又は第２主面Ｔ１に支持されている。第１主面Ｓ１に配置される発電素子部３０の数と第２主面Ｔ１に配置される発電素子部３０の数とは、互いに同じであってもよいし異なっていてもよい。また、各発電素子部３０の大きさは、互いに同じであってもよいし異なっていてもよい。 [Power generation element section 30]
As shown in FIG. 1, each power generation element section 30 is supported by the first main surface S1 or the second main surface T1 of the support substrate 20. The number of power generation element sections 30 arranged on the first main surface S1 and the number of power generation element sections 30 arranged on the second main surface T1 may be the same or different. Furthermore, the sizes of the power generating element sections 30 may be the same or different.
　各発電素子部３０は、ガス流路２１が延びる長さ方向（ｘ軸方向）に沿って間隔をあけて配置される。各発電素子部３０は、互いに電気的に直列に接続される。 The power generation element sections 30 are arranged at intervals along the length direction (x-axis direction) in which the gas flow path 21 extends. Each power generating element section 30 is electrically connected to each other in series.
　発電素子部３０は、第１集電部１、水素極２、電解質３、反応防止層４、酸素極５、第２集電部６、及びインターコネクタ７を備える。 The power generation element section 30 includes a first current collecting section 1 , a hydrogen electrode 2 , an electrolyte 3 , a reaction prevention layer 4 , an oxygen electrode 5 , a second current collecting section 6 , and an interconnector 7 .
　第１集電部１は、支持基板２０の凹部２３内に配置される。第１集電部１は、第１凹部１１及び第２凹部１２を有する。第１凹部１１内には、水素極２が配置される。第２凹部１２内には、インターコネクタ７が配置される。 The first current collector 1 is arranged within the recess 23 of the support substrate 20. The first current collector 1 has a first recess 11 and a second recess 12 . The hydrogen electrode 2 is placed inside the first recess 11 . The interconnector 7 is arranged within the second recess 12 .
　第１集電部１は、電子伝導性を有する多孔質材料によって構成される。第１集電部１は、例えば、ＮｉＯ（酸化ニッケル）とＹ２Ｏ３（イットリア）とによって構成することができる。或いは、第１集電部１は、ＮｉＯ（酸化ニッケル）と８ＹＳＺ（イットリア安定化ジルコニア）とによって構成されてもよいし、ＮｉＯ（酸化ニッケル）とＣＳＺ（カルシア安定化ジルコニア）とによって構成されてもよい。 The first current collector 1 is made of a porous material having electron conductivity. The first current collector 1 can be made of, for example, NiO (nickel oxide) and Y 2 O 3 (yttria). Alternatively, the first current collector 1 may be composed of NiO (nickel oxide) and 8YSZ (yttria stabilized zirconia), or may be composed of NiO (nickel oxide) and CSZ (calcia stabilized zirconia). Good too.
　第１集電部１の気孔率は、例えば、１０％以上５０％以下とすることができる。第１集電部１の厚さは、例えば、５０μｍ以上５００μｍ以下とすることができる。 The porosity of the first current collector 1 can be, for example, 10% or more and 50% or less. The thickness of the first current collector 1 can be, for example, 50 μm or more and 500 μm or less.
　水素極２は、第１集電部１の第１凹部１１内に配置される。水素極２には、支持基板２０及び第１集電部１を介して、ガス流路２１から燃料ガスが供給される。水素極２では、次の式（１）で表される電極反応が起こる。
　Ｈ２＋Ｏ２－→Ｈ２Ｏ＋２ｅ－　　　　　…（１） Hydrogen electrode 2 is arranged within first recess 11 of first current collector 1 . Fuel gas is supplied to the hydrogen electrode 2 from the gas flow path 21 via the support substrate 20 and the first current collector 1 . At the hydrogen electrode 2, an electrode reaction expressed by the following formula (1) occurs.
H2 + O2- → H2O +2e -... (1)
　水素極２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。水素極２は、セリウムを含むイオン伝導性材料を含有する。水素極２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２の厚さは、例えば、８μｍ超３０μｍ以下とすることができる。水素極２の構成については後述する。 The hydrogen electrode 2 is made of a porous material that has electronic conductivity and ionic conductivity. Hydrogen electrode 2 contains an ion conductive material containing cerium. The porosity of the hydrogen electrode 2 can be, for example, 10% or more and 50% or less. The thickness of the hydrogen electrode 2 can be, for example, more than 8 μm and less than 30 μm. The configuration of the hydrogen electrode 2 will be described later.
　電解質３は、水素極２を覆うように配置される。長さ方向（ｘ軸方向）における電解質３の両端部それぞれは、インターコネクタ７に接続される。 The electrolyte 3 is arranged to cover the hydrogen electrode 2. Both ends of the electrolyte 3 in the length direction (x-axis direction) are connected to an interconnector 7 .
　電解質３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３は、例えば、ＹＳＺ（８ＹＳＺ）、ＬＳＧＭ（ランタンガレート）などによって構成される。電解質３は、水素極２よりも緻密である。電解質３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３の厚さは、例えば、３μｍ以上５０μｍ以下とすることができる。 The electrolyte 3 is made of a dense material that has ionic conductivity and no electronic conductivity. The electrolyte 3 is composed of, for example, YSZ (8YSZ), LSGM (lanthanum gallate), or the like. The electrolyte 3 is denser than the hydrogen electrode 2. The porosity of the electrolyte 3 can be, for example, 0% or more and 7% or less. The thickness of the electrolyte 3 can be, for example, 3 μm or more and 50 μm or less.
　反応防止層４は、電解質３上に配置される。反応防止層４は、電解質３を介して水素極２と対応する位置に配置される。反応防止層４は、電解質３の構成材料と酸素極５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。反応防止層４は、イオン伝導性材料によって構成することができる。反応防止層４は、例えば、ＧＤＣ＝（Ｃｅ，Ｇｄ）Ｏ２（ガドリニウムドープセリア）によって構成することができる。反応防止層４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４の厚さは、例えば、１μｍ以上５０μｍ以下とすることができる。 Reaction prevention layer 4 is arranged on electrolyte 3 . The reaction prevention layer 4 is arranged at a position corresponding to the hydrogen electrode 2 with the electrolyte 3 interposed therebetween. The reaction prevention layer 4 is provided to prevent the constituent materials of the electrolyte 3 and the constituent materials of the oxygen electrode 5 from reacting to form a reaction layer with high electrical resistance. The reaction prevention layer 4 can be made of an ion conductive material. The reaction prevention layer 4 can be made of, for example, GDC=(Ce,Gd)O 2 (gadolinium-doped ceria). The porosity of the reaction prevention layer 4 can be, for example, 0.1% or more and 50% or less. The thickness of the reaction prevention layer 4 can be, for example, 1 μm or more and 50 μm or less.
　酸素極５は、反応防止層４上に配置される。酸素極５には、第２集電部６を介して、酸素を含むガス（例えば、空気）が供給される。酸素極５では、次の式（２）で表される電極反応が起こる。
　（１／２）・Ｏ２＋２ｅ－→Ｏ２－　　　…（２） Oxygen electrode 5 is placed on reaction prevention layer 4 . Oxygen-containing gas (for example, air) is supplied to the oxygen electrode 5 via the second current collector 6 . At the oxygen electrode 5, an electrode reaction expressed by the following equation (2) occurs.
(1/2)・O 2 +2e − →O 2 − …(2)
　酸素極５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５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。酸素極５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５の厚さは、例えば、１０μｍ以上１００μｍ以下とすることができる。 The oxygen electrode 5 is made of a porous material having electronic conductivity. The oxygen electrode 5 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. The porosity of the oxygen electrode 5 can be, for example, 10% or more and 50% or less. The thickness of the oxygen electrode 5 can be, for example, 10 μm or more and 100 μm or less.
　第２集電部６は、酸素極５及びインターコネクタ７に接続される。第２集電部６は、電子伝導性を有する多孔質材料によって構成される。第２集電部６は、酸素イオン伝導性を有していてもよいし、有していなくてもよい。第２集電部６は、例えば、ＬＳＣＦ、ＬＳＣ、Ａｇ（銀）、Ａｇ－Ｐｄ（銀パラジウム合金）等によって構成することができる。第２集電部６の気孔率は、例えば、２５％以上５０％以下とすることができる。第２集電部６の厚さは、例えば、５０μｍ以上５００μｍ以下とすることができる。 The second current collector 6 is connected to the oxygen electrode 5 and the interconnector 7. The second current collector 6 is made of a porous material having electron conductivity. The second current collector 6 may or may not have oxygen ion conductivity. The second current collector 6 can be made of, for example, LSCF, LSC, Ag (silver), Ag-Pd (silver-palladium alloy), or the like. The porosity of the second current collector 6 can be, for example, 25% or more and 50% or less. The thickness of the second current collector 6 can be, for example, 50 μm or more and 500 μm or less.
　インターコネクタ７は、第１集電部１の第２凹部１２内に配置される。長さ方向（ｘ軸方向）におけるインターコネクタ７の両端部それぞれは、電解質３に接続される。インターコネクタ７は、電子伝導性を有する緻密質材料によって構成される。インターコネクタ７は、例えば、ＬａＣｒＯ３（ランタンクロマイト）、（Ｓｒ，Ｌａ）ＴｉＯ３（ストロンチウムチタネート）等によって構成することができる。インターコネクタ７の気孔率は、例えば、０％以上７％以下とすることができる。インターコネクタ７の厚さは、例えば、１０μｍ以上１００μｍ以下とすることができる。 The interconnector 7 is arranged within the second recess 12 of the first current collector 1 . Both ends of the interconnector 7 in the length direction (x-axis direction) are connected to the electrolyte 3 . The interconnector 7 is made of a dense material that has electronic conductivity. The interconnector 7 can be made of, for example, LaCrO 3 (lanthanum chromite), (Sr,La)TiO 3 (strontium titanate), or the like. The porosity of the interconnector 7 can be, for example, 0% or more and 7% or less. The thickness of the interconnector 7 can be, for example, 10 μm or more and 100 μm or less.
　（水素極２の構成）
　次に、水素極２の構成について説明する。図３は、図２の部分拡大図である。 (Configuration of hydrogen electrode 2)
Next, the configuration of the hydrogen electrode 2 will be explained. FIG. 3 is a partially enlarged view of FIG. 2.
　図３に示すように、水素極２は、第１部分１０１と、第２部分１０２とを有する。 As shown in FIG. 3, the hydrogen electrode 2 has a first portion 101 and a second portion 102.
　第１部分１０１は、水素極２のうち電解質３と反対側の領域である。具体的には、第１部分１０１は、水素極２のうち電解質３と反対側の表面Ｓ２から８μｍ以内の領域である。従って、第１部分１０１の厚さは、８μｍである。本実施形態において、第１部分１０１は、第１集電部１に接続される。 The first portion 101 is a region of the hydrogen electrode 2 on the side opposite to the electrolyte 3. Specifically, the first portion 101 is a region within 8 μm from the surface S2 of the hydrogen electrode 2 on the side opposite to the electrolyte 3. Therefore, the thickness of the first portion 101 is 8 μm. In this embodiment, the first portion 101 is connected to the first current collector 1 .
　なお、水素極２の表面Ｓ２（すなわち、第１集電部１と水素極２との界面）は、Ｃｅ（セリウム）の含有率が３％となるラインによって特定される。Ｃｅの含有率は、後述する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。 Note that the surface S2 of the hydrogen electrode 2 (that is, the interface between the first current collector 1 and the hydrogen electrode 2) is specified by a line where the content of Ce (cerium) is 3%. The Ce content is obtained by line analysis using an atomic concentration profile, which will be described later.
　第２部分１０２は、水素極２のうち電解質３側の領域である。具体的には、第２部分１０２は、水素極２のうち表面Ｓ２から８μｍ超の領域である。すなわち、第２部分１０２は、水素極２のうち第１部分１０１を除いた領域である。第２部分１０２は、第１部分１０１と一体的に形成される。本実施形態において、第２部分１０２は、電解質３に接続される。 The second portion 102 is a region of the hydrogen electrode 2 on the electrolyte 3 side. Specifically, the second portion 102 is a region of the hydrogen electrode 2 that is more than 8 μm from the surface S2. That is, the second portion 102 is a region of the hydrogen electrode 2 excluding the first portion 101. The second portion 102 is integrally formed with the first portion 101. In this embodiment, the second portion 102 is connected to the electrolyte 3.
　ここで、第１部分１０１のイオン伝導度は、第２部分１０２のイオン伝導度より低い。すなわち、第１部分１０１の電極反応抵抗は、第２部分１０２の電極反応抵抗より大きい。そのため、燃料電池セル１０の作動中、第２部分１０２に比べて第１部分１０１の方が反応熱によって高温になる。従って、水素極２に供給される燃料ガスに被毒物質（例えば、シリコンなど）が含まれている場合、第１部分１０１に被毒物質を効率的に吸着させることができる。よって、水素極２のうち電極反応が活発な三相界面（反応場）を構成する第２部分１０２に被毒物質が付着することを抑制できるため、水素極２の劣化（例えば、電極反応の低下）を抑制できる。 Here, the ionic conductivity of the first portion 101 is lower than the ionic conductivity of the second portion 102. That is, the electrode reaction resistance of the first portion 101 is greater than the electrode reaction resistance of the second portion 102. Therefore, during operation of the fuel cell 10, the first portion 101 becomes higher in temperature than the second portion 102 due to the heat of reaction. Therefore, when the fuel gas supplied to the hydrogen electrode 2 contains a poisonous substance (for example, silicon, etc.), the poisonous substance can be efficiently adsorbed onto the first portion 101. Therefore, it is possible to suppress the adhesion of poisonous substances to the second portion 102 of the hydrogen electrode 2 that constitutes the three-phase interface (reaction field) where the electrode reaction is active, so that the deterioration of the hydrogen electrode 2 (for example, the electrode reaction decrease) can be suppressed.
　第１部分１０１のイオン伝導度は、次のように測定される。まず、厚さ方向（ｚ軸方向）に沿った水素極２の断面において、電解質３と反対側の表面Ｓ２から８μｍ以内の領域である第１部分１０１を確定する。次に、ＥＰＭＡ（Ｅｌｅｃｔｒｏｎ　Ｐｒｏｂｅ　Ｍｉｃｒｏ　Ａｎａｌｙｚｅｒ）を用いて第１部分１０１の元素マッピングを取得することによって、第１部分１０１の組成と各組成の含有率を特定する。次に、特定された組成を特定された含有率で混合、焼成（１３００℃５時間）した測定対象ペレットを作製する。次に、ＹＳＺによって構成され、焼成（１３００℃５時間）した端子取付け用ペレットを２つ準備する。次に、２つの端子取付け用ペレットで測定対象ペレットを挟み、電流線を端子取付け用ペレットに白金ペーストで接合するとともに、電位線を測定対象ペレットに白金ペーストで接合する。次に、４端子法にて測定対象ペレットのイオン伝導度を測定する。このように測定された測定対象ペレットのイオン伝導度が、第１部分１０１のイオン伝導度である。 The ionic conductivity of the first portion 101 is measured as follows. First, in the cross section of the hydrogen electrode 2 along the thickness direction (z-axis direction), the first portion 101 is defined as a region within 8 μm from the surface S2 on the opposite side to the electrolyte 3. Next, by obtaining elemental mapping of the first portion 101 using an Electron Probe Micro Analyzer (EPMA), the composition of the first portion 101 and the content rate of each composition are specified. Next, pellets to be measured are prepared by mixing the specified composition at the specified content rate and firing (1300° C. for 5 hours). Next, two terminal attachment pellets made of YSZ and fired (1300° C. for 5 hours) are prepared. Next, the pellet to be measured is sandwiched between two pellets for terminal attachment, and the current wire is bonded to the pellet for terminal attachment with platinum paste, and the potential wire is bonded to the pellet to be measured using platinum paste. Next, the ionic conductivity of the pellet to be measured is measured using a four-terminal method. The ionic conductivity of the pellet to be measured thus measured is the ionic conductivity of the first portion 101.
　第２部分１０２のイオン伝導度は、第１部分１０１のイオン伝導度と同様に測定される。 The ionic conductivity of the second portion 102 is measured in the same way as the ionic conductivity of the first portion 101.
　第１部分１０１及び第２部分１０２それぞれは、Ｃｅ（セリウム）を含むイオン伝導性材料と、Ｎｉ（ニッケル）とを含有する。第１部分１０１が含有するイオン伝導性材料のイオン電導度は、第２部分１０２が含有するイオン伝導性材料のイオン電導度より低くてよい。 The first portion 101 and the second portion 102 each contain an ion conductive material containing Ce (cerium) and Ni (nickel). The ionic conductivity of the ion conductive material contained in the first portion 101 may be lower than the ionic conductivity of the ion conductive material contained in the second portion 102.
　第１部分１０１が含有するイオン伝導性材料としては、Ｙ２Ｏ３（イットリア）、ＣｅＯ２（セリア）及びＧｄ２Ｏ３（ガドリア）の固溶体（以下、「Ｙ（Ｃｅ，Ｇｄ）固溶体」という。）や、Ｙ２Ｏ３、ＣｅＯ２及びＳｍ２Ｏ３（サマリア）の固溶体（以下、「Ｙ（Ｃｅ，Ｓｍ）固溶体」という。）などが挙げられる。第１部分１０１がＹ（Ｃｅ，Ｇｄ）固溶体を含有する場合、Ｙ２Ｏ３を含有する第１集電部１との熱膨張係数差を小さくすることができるため、熱膨張係数差に起因して第１部分１０１と第１集電部１との界面付近にクラックが発生することを抑制することができる。よって、第１部分１０１が含有するイオン伝導性材料としては、Ｙ（Ｃｅ，Ｇｄ）固溶体が好適である。なお、Ｙ（Ｃｅ，Ｇｄ）固溶体とは、Ｙ２Ｏ３、ＣｅＯ２及びＧｄ２Ｏ３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 ion conductive material contained in the first portion 101 is a solid solution of Y 2 O 3 (yttria), CeO 2 (ceria), and Gd 2 O 3 (gadria) (hereinafter referred to as "Y(Ce, Gd) solid solution"). ), and a solid solution of Y 2 O 3 , CeO 2 and Sm 2 O 3 (Samaria) (hereinafter referred to as "Y(Ce,Sm) solid solution"). When the first portion 101 contains a Y (Ce, Gd) solid solution, it is possible to reduce the difference in thermal expansion coefficient with the first current collector 1 containing Y 2 O 3 . Thus, generation of cracks near the interface between the first portion 101 and the first current collector 1 can be suppressed. Therefore, as the ion conductive material contained in the first portion 101, a Y (Ce, Gd) solid solution is suitable. Note that the Y (Ce, Gd) solid solution refers to one in which Y 2 O 3 , CeO 2 and Gd 2 O 3 are dissolved together to form a uniform solid phase.
　第２部分１０２が含有するイオン伝導性材料としては、希土類元素が添加されたセリア系酸化物が挙げられる。希土類元素が添加されたセリア系酸化物を第２部分１０２が含有する場合、高いイオン導電性と電子伝導性により水素極２の反応抵抗を下げることができる。よって、第２部分１０２が含有するイオン伝導性材料としては、希土類元素が添加されたセリア系酸化物が好適である。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。 The ion conductive material contained in the second portion 102 includes ceria-based oxide to which a rare earth element is added. When the second portion 102 contains a ceria-based oxide to which a rare earth element is added, the reaction resistance of the hydrogen electrode 2 can be lowered due to high ionic conductivity and electronic conductivity. Therefore, as the ion conductive material contained in the second portion 102, a ceria-based oxide to which a rare earth element is added is suitable. 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.
　第１部分１０１のイオン伝導度は、第１部分１０１が含有するイオン伝導性材料の組成と、イオン伝導性材料の含有率とによって調整することができる。第１部分１０１におけるＣｅを含むイオン伝導性材料の含有率は、３５ｍｏｌ％以上６５ｍｏｌ％以下とすることができる。 The ionic conductivity of the first portion 101 can be adjusted by the composition of the ion conductive material contained in the first portion 101 and the content rate of the ion conductive material. The content of the ion conductive material containing Ce in the first portion 101 can be 35 mol% or more and 65 mol% or less.
　第２部分１０２のイオン伝導度は、第２部分１０２が含有するイオン伝導性材料の組成と、イオン伝導性材料の含有率とによって調整することができる。第２部分１０２におけるＣｅを含むイオン伝導性材料の含有率は、３５ｍｏｌ％以上６５ｍｏｌ％以下とすることができる。 The ionic conductivity of the second portion 102 can be adjusted by the composition of the ion conductive material contained in the second portion 102 and the content rate of the ion conductive material. The content of the ion conductive material containing Ce in the second portion 102 can be 35 mol% or more and 65 mol% or less.
　第１部分１０１及び第２部分１０２におけるＣｅを含むイオン伝導性材料の含有率は、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、厚さ方向（図３のｚ軸方向）に沿った断面において、ＥＰＭＡを用いてｚ軸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 content of the ion conductive material containing Ce in the first portion 101 and the second portion 102 is obtained by line analysis using an atomic concentration profile, that is, elemental mapping using EPMA. Specifically, concentration distribution data of each element is obtained by performing line analysis in the z-axis direction using EPMA in a cross section along the thickness direction (z-axis direction in FIG. 3). Note that EPMA is a concept that includes EDS (Energy Dispersive x-ray Spectroscopy).
　第１部分１０１におけるＮｉの含有率は、３５ｍｏｌ％以上６５ｍｏｌ％以下とすることができる。第２部分１０２におけるＮｉの含有率は、３５ｍｏｌ％以上６５ｍｏｌ％以下とすることができる。 The Ni content in the first portion 101 can be 35 mol% or more and 65 mol% or less. The Ni content in the second portion 102 can be 35 mol% or more and 65 mol% or less.
　第１部分１０１及び第２部分１０２におけるＮｉ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。Ｎｉは、燃料ガスが供給された還元雰囲気において金属Ｎｉとして存在していることが好ましいが、燃料ガスが供給されない場合にはＮｉＯとして存在していてもよい。 The Ni content in the first portion 101 and the second portion 102 is obtained by line analysis using the atomic concentration profile described above. Ni is preferably present as metal Ni in a reducing atmosphere supplied with fuel gas, but may be present as NiO when no fuel gas is supplied.
　（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、いわゆる横縞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 above embodiment, a so-called horizontal stripe type 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、横縞型の燃料電池セルのほか、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。 In addition to horizontal striped fuel cells, electrochemical cells include vertical striped fuel cells, flat plate fuel cells, cylindrical fuel cells, and hydrogen generation cells that utilize the electrolysis reaction of water. An example is an electrolytic cell that performs this. 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、発電素子部３０は、反応防止層４を備えることとしたが、反応防止層４を備えていなくてもよい。 [Modification 2]
In the above embodiment, the power generation element section 30 is provided with the reaction prevention layer 4, but the reaction prevention layer 4 may not be provided.
１０　　燃料電池セル
２０　　支持基板
３０　　発電素子部
１　　　第１集電部
２　　　水素極
１０１　第１部分
１０２　第２部分
３　　　電解質
４　　　反応防止層
５　　　酸素極
６　　　第２集電部
７　　　インターコネクタ 10 Fuel cell 20 Support substrate 30 Power generation element section 1 First current collecting section 2 Hydrogen electrode 101 First section 102 Second section 3 Electrolyte 4 Reaction prevention layer 5 Oxygen electrode 6 Second current collecting section 7 Interconnector

Claims (2)

  1. 　セリウムを含むイオン伝導性材料を含有する水素極と、
    　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、
    　前記水素極は、前記電解質と反対側の表面から８μｍ以内の第１部分と、前記表面から８μｍ超の第２部分とを有し、
    　前記第１部分のイオン伝導度は、前記第２部分のイオン伝導度より低い、
    電気化学セル。     a hydrogen electrode containing an ion conductive material containing cerium;
    an oxygen electrode,
    an electrolyte disposed between the hydrogen electrode and the oxygen electrode;
    Equipped with
    The hydrogen electrode has a first portion that is within 8 μm from the surface opposite to the electrolyte, and a second portion that is more than 8 μm from the surface,
    The ionic conductivity of the first portion is lower than the ionic conductivity of the second portion.
    electrochemical cell.
  2. 　前記第１部分は、イットリア、セリア及びガドリアの固溶体を含有し、
    　前記第２部分は、希土類元素が添加されたセリア系酸化物を含有する、
    請求項１に記載の電気化学セル。     The first portion contains a solid solution of yttria, ceria and gadoria,
    The second portion contains a ceria-based oxide to which a rare earth element is added.
    An electrochemical cell according to claim 1.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08213029A (en) * 1995-02-06 1996-08-20 Fujikura Ltd Fuel electrode of solid electrolyte fuel cell
JP2006024545A (en) * 2003-11-10 2006-01-26 Mitsubishi Materials Corp Power generation cell for solid electrolyte fuel battery
JP2019008914A (en) * 2017-06-21 2019-01-17 日本特殊陶業株式会社 Electrochemical cell and electrochemical stack

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08213029A (en) * 1995-02-06 1996-08-20 Fujikura Ltd Fuel electrode of solid electrolyte fuel cell
JP2006024545A (en) * 2003-11-10 2006-01-26 Mitsubishi Materials Corp Power generation cell for solid electrolyte fuel battery
JP2019008914A (en) * 2017-06-21 2019-01-17 日本特殊陶業株式会社 Electrochemical cell and electrochemical stack

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