WO2020091151A1 - Air electrode for solid oxide fuel cell to which electrochemical method is applied and manufacturing method therefor - Google Patents

Air electrode for solid oxide fuel cell to which electrochemical method is applied and manufacturing method therefor Download PDF

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WO2020091151A1
WO2020091151A1 PCT/KR2019/002034 KR2019002034W WO2020091151A1 WO 2020091151 A1 WO2020091151 A1 WO 2020091151A1 KR 2019002034 W KR2019002034 W KR 2019002034W WO 2020091151 A1 WO2020091151 A1 WO 2020091151A1
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scaffold
gdc
fuel cell
solid oxide
oxide fuel
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Korean (ko)
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이승복
송락현
임탁형
홍종은
사이드레만
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한국에너지기술연구원
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    • 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
    • H01M4/88—Processes of manufacture
    • H01M4/8803—Supports for the deposition of the catalytic active composition
    • H01M4/8814—Temporary supports, e.g. decal
    • H—ELECTRICITY
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    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H—ELECTRICITY
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    • 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
    • H01M4/8605—Porous electrodes
    • H—ELECTRICITY
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    • 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
    • H01M4/8663—Selection of inactive substances as ingredients for catalytic active masses, e.g. binders, fillers
    • 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
    • H01M4/88—Processes of manufacture
    • 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
    • H01M4/88—Processes of manufacture
    • H01M4/8825—Methods for deposition of the catalytic active composition
    • H01M4/8853—Electrodeposition
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8878—Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body
    • H01M4/8882—Heat treatment, e.g. drying, baking
    • 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
    • H01M4/90—Selection of catalytic material
    • H—ELECTRICITY
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    • 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
    • H01M4/90—Selection of catalytic material
    • H01M4/9016—Oxides, hydroxides or oxygenated metallic salts
    • H01M4/9025—Oxides specially used in fuel cell operating at high temperature, e.g. SOFC
    • H01M4/9033—Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites
    • 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
    • H01M8/124—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte
    • H01M8/1246—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides
    • H01M8/1253—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides the electrolyte containing zirconium oxide
    • 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
    • H01M8/124—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte
    • H01M8/1246—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides
    • H01M8/126—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides the electrolyte containing cerium oxide
    • 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
    • H01M2008/1293—Fuel cells with solid oxide electrolytes
    • 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
    • H01M4/8647—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
    • H01M4/8652—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites as mixture
    • 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
    • H01M4/90—Selection of catalytic material
    • H01M4/9016—Oxides, hydroxides or oxygenated metallic salts
    • H01M4/9025—Oxides specially used in fuel cell operating at high temperature, e.g. SOFC
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a method of manufacturing an anode, an anode manufactured thereby, and a solid oxide fuel cell comprising the same.
  • a solid oxide fuel cell is an energy conversion device that directly converts chemical energy of fuels such as hydrogen and hydrocarbons into electrical energy.
  • Solid oxide fuel cells have high efficiency and low emission of pollutants.
  • the electrochemical performance of a solid oxide fuel cell is determined by the reaction rate of the oxygen reduction reaction (ORR) of the cathode.
  • Conventional solid oxide fuel cell cathodes have conductivity La 0 . 8 Sr 0 . 2 MnO 3 (LSM) or ion-electrically conductive La 0 . 6 Sr 0 . 4 Co 0 . 2 Fe 0 . 8 O3- ⁇ (LSCF), consisting of a material having catalytic activity and electrical conductivity, or an ion conductor such as Y 2 O3-stabilized ZrO 2 (YSZ).
  • LSM la 0 . 8 Sr 0 . 2 MnO 3
  • LSCF ion-electrically conductive La 0 . 6 Sr 0 . 4 Co 0 . 2 Fe 0 . 8 O3- ⁇
  • YSZ Y 2 O3-stabilized ZrO 2
  • the production of the cathode by the impregnation method forms a porous ion-conducting scaffold (ICS) on the electrolyte by high temperature sintering, impregnates the mixed metal precursor solution into the scaffold, and thermally decomposes it. It goes through the process of forming a perovskite phase. At this time, a continuous ion conduction path is formed by high temperature sintering of the porous ion conduction scaffold.
  • ICS porous ion-conducting scaffold
  • the nano-sized perovskite oxide is uniformly distributed on the wall surface of the scaffold, and the formation of an insulating pyrochlore phase is suppressed.
  • the manufacturing method by the impregnation method requires repeated impregnation and calcination for proper catalyst loading, which makes the manufacturing process inefficient and takes excessive time.
  • the present inventors have researched and developed an efficient method of manufacturing a solid oxide fuel cell cathode to solve the above problems, and combine chemically assisted electrodeposition and infiltration techniques to form nano fiber-like La 1 - x Sr x CoO.
  • the present invention was completed by preparing a 3 / GDC composite cathode.
  • An object of the present invention is a composite cathode of a nanofiber form of lanthanum-strontium-cobalt (La-Sr-Co) oxide and a porous ion conducting scaffold that combines chemically assisted electrodeposition and infiltration techniques with a solid oxide fuel cell. It is to provide a manufacturing method.
  • Another object of the present invention is a composite of a lanthanum-strontium-cobalt oxide / porous ion conduction scaffold in the form of nanofibers in which a lanthanum-strontium-cobalt (La-Sr-Co) oxide is formed on a porous ion conducting scaffold. It is to provide a cathode, and a solid oxide fuel cell comprising the composite cathode.
  • It provides a method for manufacturing a cathode of a solid oxide fuel cell comprising a.
  • GDC Gd-doped ceria
  • Heat-treating the GDC ink after screen printing on the ScCeSZ electrolyte layer It may be prepared by a method comprising a.
  • the carbon nanotube is formed of the carbon nanotube.
  • Growing carbon nanotubes from the transition metal nanoparticles by supplying a carbon source may be formed by a method comprising a.
  • La x Sr 1 - x CoO 3 in the form of nanofibers formed on the porous ion conducting scaffold (where X is a prime number of 0 ⁇ X ⁇ 1);
  • a cathode for a solid oxide fuel cell is provided.
  • the porous ion conducting scaffold may be a porous Gd-doped ceria (GDC) scaffold.
  • GDC Gd-doped ceria
  • Electrolyte layer provided between the cathode and the anode
  • It provides a solid oxide fuel cell comprising a.
  • the anode may be formed of NiO-ScCeSZ or NiO-YSZ.
  • the electrolyte layer may be formed of at least one of yttrium stabilized zirconia, scandium stabilized zirconia, and gadolium doped ceria.
  • the new manufacturing method of La 1 - x Sr x CoO 3 / GDC composite cathode in the form of nanofibers according to the present invention uses a lower manufacturing temperature (approximately 900 ° C) compared to conventional sintering, which uses the secondary phase as the ScCeSZ electrolyte. Formation can be avoided.
  • the manufacturing method according to the present invention provides excellent control over La 1 - x Sr x CoO 3 loading, and can achieve the desired loading in a single electrodeposition step.
  • the composite cathode in the form of a new nanofiber according to the present invention can provide a large surface area and help transport the oxidant through the nanoporous structure.
  • the anode-assisted button cell produced by the new manufacturing technology according to the present invention can exhibit high electrochemical performance (about 613 mW cm - 2 at 750 ° C) while using humidified hydrogen as a fuel.
  • FIG. 1 is a view showing a schematic diagram of a manufacturing process of nanofiber La x Sr 1 - x CoO 3 / GDC composite cathode for SOFC.
  • FIG. 2 is a view showing an SEM image of the anode-supported SOFC.
  • FIG. 3 is an SEM image of (a) primitive, (b) Co nanoparticle deposited, and (c) CNT modified GDC scaffold.
  • FIG. 4 is a view showing SEM images of (a) nanofiber La x Sr 1 - x CoO 3 / GDC and (b) a conventional LSC / GDC composite cathode.
  • FIG. 6 is a view showing the results of XRD analysis of the finally produced nanofiber La x Sr 1 - x CoO 3 / GDC cathode.
  • FIG. 7 is a view showing a polarization curve of (FC) SOFC having (a) nanofiber La x Sr 1 - x CoO 3 / GDC and (b) a conventional LSC / GDC composite cathode.
  • FIG. 8 is a graph showing the electrochemical impedance plot of SOFC having (a) nanofiber La x Sr 1 - x CoO 3 / GDC and (b) a conventional LSC / GDC composite cathode.
  • the present invention is to prepare a composite cathode of a nanofiber form of lanthanum-strontium-cobalt (La-Sr-Co) oxide and a porous ion conducting scaffold that combine chemically assisted electrodeposition and infiltration techniques with a solid oxide fuel cell. Provide a method.
  • the porous ion conducting scaffold in step i) may be a porous zirconia-ceria ion conducting scaffold or a porous ceria-gadolinium ion conducting scaffold.
  • the porous ion conductive scaffold comprises the steps of preparing a GDC ink in which Gd-doped ceria (GDC) powder, a solvent, a binder, and a pore-forming agent are mixed; And, the GDC ink is screen-printed on the ScCeSZ electrolyte layer, followed by heat treatment; it is preferably prepared by a method comprising a.
  • GDC Gd-doped ceria
  • a "nano fiber" LaCoO 3 (LCO) perovskite is cathodic catalyst of a solid oxide fuel cell by a route based on electrodeposition, for example, chemically assisted electrodeposition (CAED). Formed with.
  • CAED chemically assisted electrodeposition
  • the formation of the carbon nanotubes comprises: dispersing and dispersing transition metal nanoparticles in the scaffold; And supplying a carbon source to grow carbon nanotubes from the transition metal nanoparticles.
  • carbon nanotubes were formed by catalytic chemical vapor deposition (CCVD) of C 2 H 4 on a porous zirconia-based ion conductive scaffold. Catalytic chemical vapor deposition can achieve high reliability and high purity.
  • Fe, Ni, or Co may be used as the transition metal nanoparticles.
  • a cobalt nitrate precursor solution was impregnated with a porous ion conducting scaffold to provide a catalyst for carbon nanotube growth.
  • a lanthanum-cobalt (La-Co) oxide is electrodeposited on a carbon nanotube.
  • lanthanum-cobalt hydroxide (La-Co-OH) was deposited on carbon nanotubes by chemically assisted electrodeposition (CAED).
  • the scaffold is heat-treated in step iii) to remove carbon nanotubes.
  • the heat treatment is preferably a low-temperature heat treatment of 700 to 900 °C.
  • the scaffold may be heat treated at a temperature of 900 ° C. or less to form perovskite type LaCoO 3 (LCO) through thermal conversion.
  • LCO perovskite type LaCoO 3
  • the carbon nanotubes are completely decomposed, leaving only the fibrous LCO structure inside the ion conducting scaffold.
  • LaCoO 3 -based materials easily react with the zirconia-based electrolyte to form an insulating pyrochlore phase.
  • formation of an insulating phase is suppressed by a low temperature heat treatment process of 900 ° C or less.
  • strontium (Sr) is infiltrated into the scaffold in step iv). Infiltrating the strontium is dissolved by adding strontium nitrate powder to a solvent to prepare a strontium nitrate solution; And, it is preferred that the strontium nitrate solution is added to the scaffold deposited with a lanthanum-cobalt oxide, followed by infiltration and drying.
  • the scaffold is heat-treated in step v) to form a nanofiber lanthanum-strontium-cobalt (La-Sr-Co) oxide.
  • the heat treatment is preferably a low-temperature heat treatment of 800 to 1000 °C.
  • the secondary phase is formed with the ScCeSZ electrolyte, such secondary phase formation can be avoided by a low-temperature heat treatment process of 1000 ° C or lower.
  • a chemically assisted electrodeposition and penetration technique is combined with a solid oxide fuel cell, such that La 0 . 6 after the CoO 3 a chemical deposition with a porous GDC the support followed by heat treatment at 900 °C by infiltration Next Sr La 1 - x Sr x CoO by generating a three-phase, nanofibers, in the form of La 1 - x Sr x CoO 3 (where , X is 0 ⁇ X ⁇ 1 prime) -GDC composite cathode was prepared.
  • a) GDC ink containing 30% by weight PMMA pore former on a high density ScCeSZ electrolyte of an anode support button cell is screen printed and sintered at 1300 ° C. to produce a high porosity GDC scaffold.
  • b) a 0.5 M cobalt nitrate solution to act as a seed for CNT growth was penetrated into a porous GDC scaffold by catalytic chemical vapor deposition of 750 ° C. carbon using ethylene as the carbon source, and then c) La (NO 3) 3 -6H 2 O and Co (NO 3) 2 -6H by chemical auxiliary electrodeposition of La and Co from an aqueous electrolyte containing La 2 O 0.
  • the deposited GDC scaffold was heat treated at 750 ° C. for 5 hours, and then e) nitric acid in which strontium nitrate powder was completely dissolved in ethylene glycol.
  • the strontium solution was La 0 . 6
  • FIG. 1 A schematic diagram of a method for manufacturing a La 1 - x Sr x CoO 3 in a nanofiber form according to the present invention (where X is a prime number of 0 ⁇ X ⁇ 1) -GDC composite cathode is shown in FIG. 1.
  • the new method of manufacturing La 1 - x Sr x CoO 3 in the nanofiber form according to the present invention uses ScCeSZ using a lower manufacturing temperature than conventional sintering.
  • the formation of a secondary phase with the electrolyte can be avoided, providing good control over La 1 - x Sr x CoO 3 loading and achieving the desired loading in a single electrodeposition step.
  • La 1 - x Sr x CoO 3 (where X is a prime number of 0 ⁇ X ⁇ 1) -GDC composite cathode in the form of nanofibers according to the present invention can provide a large surface area, and an oxidizing agent through a nanoporous structure
  • the anode support button cell using the cathode may exhibit high electrochemical performance (613 mW cm ⁇ 2 at 750 ° C.) while using humidified hydrogen as a fuel.
  • the present invention provides a cathode of a solid oxide fuel cell manufactured by the manufacturing method according to the present invention.
  • the present invention is a porous ion conducting scaffold; And La x Sr 1 - x CoO 3 (where X is a prime number of 0 ⁇ X ⁇ 1) in the form of nanofibers formed on the porous ion conducting scaffold.
  • the porous ion conducting scaffold is preferably a porous Gd-doped ceria (GDC) scaffold.
  • GDC Gd-doped ceria
  • the present invention provides a solid oxide fuel cell including the cathode of the solid oxide fuel cell according to the present invention.
  • the present invention is the air electrode according to the present invention; Anode; And an electrolyte layer provided between the air electrode and the fuel electrode.
  • the anode may be formed of NiO-ScCeSZ or NiO-YSZ.
  • the electrolyte layer may be formed of at least one of yttrium stabilized zirconia, scandium stabilized zirconia, and gadolium doped ceria.
  • NiO (Konjundo Chemical Laboratory, Japan) and YSZ (Fuel Cell Materials, USA) (56:44) powders were mixed by ball milling with 12% by weight activated carbon pore former using ethanol as a solvent.
  • the mixed powder was dried in an oven and compressed into a round green disk to serve as an anode support for the button cell.
  • the green anode support was pre-sintered at 1100 ° C. for 5 hours in air.
  • the NiO-ScCeSZ anode functional layer and the ScCeSZ electrolyte layer were immersed on the pre-sintered anode support and calcined in air at 1400 ° C. for 5 hours.
  • GDC ink for producing porous GDC scaffolds by adding appropriate amounts of ⁇ -terpinol, ethyl cellulose and PMMA (3 ⁇ m) as GDC powder (Fuel Cell Materials USA) as solvent, binder and pore former, respectively. was prepared.
  • the components of the GDC scaffold ink were mixed in an oily centrifugal mixer (Thinky SR-500).
  • the GDC ink was then screen printed onto a high density ScCeSZ electrolyte layer, and then sintered in air at 1300 ° C. for 3 hours.
  • Carbon nanotube (CNT) network is La 0 . 6 CoO 3 was deposited on the GDC scaffold by catalytic vapor deposition to provide a conductive surface for chemically assisted electrodeposition. To do so, 0.5 M cobalt nitrate aqueous solution was infiltrated into the porous GDC scaffold to form Co nanoparticles for the growth of CNTs.
  • the button cell was sealed into a steel jig but only the GDC scaffold was exposed to the surrounding environment.
  • the steel jig including the button cell was placed in a tube furnace and heated to 750 ° C in a flowing nitrogen atmosphere. Thereafter, nitrogen gas was replaced with C 2 H 4 and the gas flow was maintained for 5 minutes, during which carbon was deposited in the form of an interconnected CNT network.
  • La 0 La 0 .
  • KNO 3 99.99%, Sigma Aldrich
  • the setup used for electrodeposition of LaCoO 3 consists of two compartment electrochemical cells. The two compartments of the electrochemical cell were separated by an ion exchange membrane (APS4, Asahi Glass).
  • the compartment 1 contained a button cell (working electrode) and an aqueous electrolyte comprising La (NO 3 ) 3 -6H 2 O and Co (NO 3 ) 2 -6H 2 O. Desired stoichiometric deposition, that is from 0.6: to obtain La for Co ratio of 1, Co 2 + ratio is fixed at 5 mM, and in a quantity-aqueous electrolyte of the La 3 + 3, 3.2, 3.4, 3.6, and 3.8 mM of various Was made. 3, 3.2, 3.4, an aqueous electrolyte containing La 3 + 3.6 and 3.8 mM, respectively named as LC1, LC2, LC3, LC4 and LC5.
  • the button cell was masked using an organic polymer paint so that only the carbon-coated GDC support (working electrode) was exposed to the nitric acid solution.
  • Section (2) contained a Pt mesh (relative electrode) and an aqueous electrolyte of KNO 3 .
  • Electrodeposition was electrostatically compensated by cathodically polarizing the working electrode. After the electrodeposition process was completed, the button cell was removed from the electrolyte, and nitrate was removed by washing with deionized water. Then, the button cells were heat treated at 750 ° C. in air for 5 hours to remove CNTs.
  • a strontium solution was prepared using ethylene glycol as the solvent.
  • the solution was prepared by slowly adding strontium nitrate powder to ethylene glycol while stirring using a magnetic rod on a hot stir flat. Ethylene glycol was heated to 100 ° C. for complete dissolution of strontium nitrate.
  • the concentration of the strontium nitrate solution was La 0 deposited on the GDC scaffold . 6 Adjusted according to the amount of CoO 3 .
  • La 0 under a single infiltration of hot strontium nitrate solution . 6 was added to the GDC scaffold deposited with CoO 3 . After drying completely in an oven at 95 ° C, the button cell was placed in a furnace and heat-treated at 900 ° C to form nanofibrous La x Sr 1-x CoO 3 .
  • a conventional LSC / GDC cathode was prepared using screen printing and sintering technology (see Korean Patent Application No. 10-2017-0159533).
  • LSC / GDC screen printing inks were prepared by mixing LSC (Fuel Cell Materials USA), GDC powder with an appropriate amount of ⁇ - terpineol and ethyl cellulose in an oily centrifugal mixer.
  • LSC / GDC ink was screen-printed on the high-density ScCeSZ electrolyte of the half cell supported by the anode and sintered at 1100 ° C for 2 hours.
  • nanofiber La 1 -x Sr x CoO 3 / GDC composite cathode and the conventional LSN / GDC composite cathode were observed using a scanning electron microscope (SEM, NOVA NANOSEM450, FEI).
  • the SEM micrograph of the anode support button cell is as shown in FIG. 2.
  • the button cell consisted of a NiO / YSZ support, a dense NiO / ScCeSZ anode functional layer, a dense ScCeSZ electrolyte layer and a porous GDC scaffold.
  • the ScCeSZ electrolyte layer was completely compact and the anode functional layer and GDC scaffold were well connected.
  • the GDC scaffold consisted of a uniform interconnected spherical pore network ( Figure 2).
  • the GDC scaffold is La 0 . 6 It must have electrical conductivity for chemical assisted electrodeposition of CoO 3 .
  • interconnected CNT networks were made on the GDC scaffold.
  • Transition metal nanoparticles such as Co, Ni and Fe act as catalysts for the growth of CNTs. Since Co is reported to improve the performance of the SOFC cathode in the present invention, it was used for the growth of CNTs.
  • Co was introduced into the GDC scaffold by infiltration of an aqueous solution of cobalt nitrate. The Co nanoparticles were formed by thermal decomposition of cobalt nitrate while heating the button cell (FIG. 3B), and these Co nanoparticles served as seeds for carbon deposition at 750 ° C. from C 2 H 4 gas.
  • the GDC scaffold modified by CNT deposition is as shown in FIGS. 3C and 3D. Carbon deposition was uniform in the GDC scaffold, and carbon deposits could also be observed at the electrolyte / cathode interface.
  • the GDC scaffold modified with CNTs was found to be sufficiently conductive for the electrodeposition process.
  • the SEM image of the GDC scaffold was confirmed after final heat treatment at 900 ° C, as shown in FIG. 4A. It was found that the deposition was in the form of a dendrites of nanofibers. This unique shape of the La x Sr 1 - x CoO 3 cathode provided an extended surface area due to the large triple phase boundary and allowed the flow of oxidant through the nanofiber structure.
  • Conventional LSC / GDC cathodes were also produced by screen printing and sintering processes. The SEM image of the conventional LSC / GDC cathode is as shown in FIG. 4B. A clear difference could be observed because conventional LSC / GDC cathodes consist of rugged particles that exhibit a relatively dense microstructure with reduced surface area.
  • La 0 . 6 The chemical composition of CoO 3 was observed using energy dispersive X-ray spectroscopy (EDS QUANTAX200, BRUKER). X-ray diffraction analysis was performed to confirm the formation of La x Sr 1 - x CoO 3 phase (XRD, 2500 D / MAX, Rigaku).
  • XRD analysis of the nanofibrous La x Sr 1 - x CoO 3 / GDC composite cathode finally produced after the heat treatment step at 900 ° C. was confirmed (FIG. 6).
  • the XRD plot shows the high intensity peak of GDC present as a scaffold material.
  • the ScCeSZ peak is detected as background interference to the ScCeSZ electrolyte because the thickness of the cathode layer is small.
  • the peak of the La x Sr 1 - x CoO 3 cathode was detected to indicate the formation of the desired perovskite cathode prepared by chemically assisted deposition and infiltration techniques.
  • a small amount of cobalt oxide was also detected as an impurity.
  • the presence of cobalt oxide in the cathode can have a beneficial effect on the electrochemical performance of SOFC.
  • Electrochemical performance was recorded by measuring current-voltage-output (IVP) and impedance data at 700, 750 and 800 ° C using humidified hydrogen and air as fuel and oxidizer, respectively.
  • I-V data was acquired using a DC load device.
  • Impedance data was recorded using a BioLogic (SP240) device in the frequency range of 1 MHz to 100 mHz with an amplitude of 14 mV under open circuit voltage conditions.
  • electrochemical for anode support button cells using nanofiber La x Sr 1 - x CoO 3 / GDC composite cathodes and conventional LSC / GDC composite cathodes at various operating temperatures (700, 750 and 800 ° C.) Performance was measured. All SOFCs exhibited high OCV (> 1.1 V) values through a complete electrolyte layer and hermetic sealing. SOFCs with nanofiber La x Sr 1 -x CoO 3 / GDC composite cathodes exhibited high power densities of 351, 613 and 950 mW cm -2 at 700, 750 and 800 ° C, respectively.
  • SOFCs having a conventional LSC / GDC composite cathode exhibited low power densities of 82, 145 and 245 mW cm -2 at 700, 750 and 800 ° C, respectively.
  • SOFCs with nanofiber La x Sr 1 -x CoO 3 / GDC composite cathodes prepared by chemically assisted deposition and infiltration techniques are 4.28 times more than SOFCs with conventional LSC / GDC composite cathodes at operating temperatures of 700 ° C. It showed great performance. It was confirmed that the increased performance was due to the nanofiber microstructure of the new cathode and low manufacturing temperature.
  • Electrochemical impedance data was measured under open circuit voltage conditions for SOFCs with nanofiber La x Sr 1 - x CoO 3 / GDC composite cathodes and conventional LSC / GDC composite cathodes at various operating temperatures, as shown in FIG. 8.
  • the SOFC with the nanofiber La x Sr 1 - x CoO 3 / GDC composite cathode exhibits excellent performance showing smaller ohmic and polarization resistance compared to the SOFC with the conventional LSC / GDC composite cathode.
  • Various electrochemical performance parameters measured for SOFC using nanofiber La x Sr 1 - x CoO 3 / GDC composite cathode and conventional LSC / GDC composite cathode are listed in Table 3 below.

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Abstract

The present invention relates to a nanofibrous La1-xSrxCoO3/GDC composite cathode using a combination of chemically assisted electrodeposition and infiltration techniques for solid oxide fuel cells and a manufacturing method therefor and, more specifically, to a nanofibrous La1-xSrxCoO3/GDC composite cathode manufactured by chemically electrodepositing a lanthanum-cobalt (La-Co) oxide on a porous GDC scaffold, heat-treating same, and then infiltrating Sr thereinto to form a La1-xSrxCoO3 phase, and a manufacturing method therefor. The nanofibrous La1-xSrxCoO3/GDC composite cathode according to the present invention can provide a large surface area, can assist in the transport of an oxidant through the nanoporous structure, and can provide high electrochemical performances, and thus can be effectively used for solid oxide fuel cells.

Description

전기화학기법을 적용한 고체산화물연료전지 공기극 및 이의 제조방법Electrode of solid oxide fuel cell using electrochemical technique and its manufacturing method
본 발명은 공기극의 제조방법, 그에 의해 제조된 공기극 및 이를 포함하는 고체산화물 연료전지에 관한 것이다. The present invention relates to a method of manufacturing an anode, an anode manufactured thereby, and a solid oxide fuel cell comprising the same.
고체산화물 연료전지(solid oxide fuel cell, SOFC)는 수소, 탄화수소와 같은 연료의 화학에너지를 전기에너지로 직접 전환하는 에너지 전환 장치이다. 고체산화물 연료전지는 고효율과 적은 오염원 배출이라는 특성을 갖는다. 일반적으로, 고체산화물 연료전지의 전기화학적 성능은 공기극의 산소환원반응(oxygen reduction reaction, ORR)의 반응속도에 의해 결정된다. A solid oxide fuel cell (SOFC) is an energy conversion device that directly converts chemical energy of fuels such as hydrogen and hydrocarbons into electrical energy. Solid oxide fuel cells have high efficiency and low emission of pollutants. In general, the electrochemical performance of a solid oxide fuel cell is determined by the reaction rate of the oxygen reduction reaction (ORR) of the cathode.
산소환원반응은 공기극 촉매, 산소가스 및 전해질이 만나는 삼상경계 (triple phase boundaries, TPBs)에서 주로 일어난다. 종래의 고체산화물 연료전지 공기극은 도전성 La0 . 8Sr0 . 2MnO3 (LSM) 또는 이온-전기 전도성 La0 . 6Sr0 . 4Co0 . 2Fe0 . 8O3-δ(LSCF)와 같이, 촉매활성 및 전기전도성을 가지는 물질 또는 Y2O3-안정화 ZrO2 (YSZ)와 같은 이온 전도체로 이루어졌다. 이와 같은, 복합 구조는 삼상경계를 공기극 전체로 확장하여 준다. Oxygen reduction reactions occur mainly at the triple phase boundaries (TPBs) where the cathode catalyst, oxygen gas and electrolyte meet. Conventional solid oxide fuel cell cathodes have conductivity La 0 . 8 Sr 0 . 2 MnO 3 (LSM) or ion-electrically conductive La 0 . 6 Sr 0 . 4 Co 0 . 2 Fe 0 . 8 O3-δ (LSCF), consisting of a material having catalytic activity and electrical conductivity, or an ion conductor such as Y 2 O3-stabilized ZrO 2 (YSZ). Such a composite structure extends the three-phase boundary to the entire air electrode.
최근에는 공기극의 나노 구조를 제어하고, 최적화하여 고체산화물 연료전지의 전기화학적 성능을 향상시키려는 기술적 접근이 진행되어 왔다. 특히, 함침 (infiltration or impregnation)에 의해 나노 구조의 공기극을 제조하는 방법은 고체산화물 연료전지 성능을 향상시키는데 효과적인 것으로 알려졌다. Recently, a technical approach has been made to improve the electrochemical performance of a solid oxide fuel cell by controlling and optimizing the nanostructure of the cathode. In particular, it has been found that a method of manufacturing a nano-structured cathode by infiltration or impregnation is effective in improving the performance of a solid oxide fuel cell.
함침법에 의한 공기극의 제조는, 고온 소결에 의해 다공성 이온전도 스캐폴드(ion-conducting scaffold, ICS)를 전해질 상에 형성시키고, 혼합금속 전구체 용액을 스캐폴드 내부로 함침한 후 열분해에 의해, 페로브스카이트(perovskite)상을 형성하는 과정을 거친다. 이때, 다공성 이온전도 스캐폴드의 고온소결에 의해, 연속적인 이온전도 경로가 형성된다. The production of the cathode by the impregnation method forms a porous ion-conducting scaffold (ICS) on the electrolyte by high temperature sintering, impregnates the mixed metal precursor solution into the scaffold, and thermally decomposes it. It goes through the process of forming a perovskite phase. At this time, a continuous ion conduction path is formed by high temperature sintering of the porous ion conduction scaffold.
또한, 함침과 촉매의 저온 열처리에 의해, 나노 크기의 페로브스카이트 산화물이 스캐폴드의 벽면에 균일하게 분포하고, 절연성 파이로클로르(pyrochlore) 상이 형성되는 것이 억제된다. In addition, by impregnation and low temperature heat treatment of the catalyst, the nano-sized perovskite oxide is uniformly distributed on the wall surface of the scaffold, and the formation of an insulating pyrochlore phase is suppressed.
그러나 함침법에 의한 제조방법은, 적절한 촉매 적재를 위해, 반복적인 함침과 하소(calcination)를 필요로 하며, 이로 인해 제조공정이 비효율적이고, 과다한 시간을 소요하게 된다. However, the manufacturing method by the impregnation method requires repeated impregnation and calcination for proper catalyst loading, which makes the manufacturing process inefficient and takes excessive time.
이에, 본 발명자들은 상기와 같은 문제점을 해결하기 위해 효율적인 고체산화물 연료전지 공기극의 제조 방법을 연구 개발한 결과, 화학적으로 보조된 전착 및 침투 기술을 결합하여 나노섬유 형태의 La1 - xSrxCoO3/GDC 복합 캐소드를 제조함으로써, 본 발명을 완성하였다.Accordingly, the present inventors have researched and developed an efficient method of manufacturing a solid oxide fuel cell cathode to solve the above problems, and combine chemically assisted electrodeposition and infiltration techniques to form nano fiber-like La 1 - x Sr x CoO. The present invention was completed by preparing a 3 / GDC composite cathode.
[선행기술문헌][Advanced technical literature]
[특허문헌][Patent Document]
일본 특허공개번호 제2013-516731호Japanese Patent Publication No. 2013-516731
일본 특허공개번호 제2017-157553호Japanese Patent Publication No. 2017-157553
한국 특허등록번호 제10-1334903호Korean Patent Registration No. 10-1334903
본 발명의 목적은 고체 산화물 연료 전지에 화학적으로 보조된 전착 및 침투 기술을 결합한 나노섬유 형태의 란타넘-스트론튬-코발트(La-Sr-Co) 산화물과 다공성 이온전도 스캐폴드(scaffold)의 복합 캐소드의 제조 방법을 제공하는 것이다. An object of the present invention is a composite cathode of a nanofiber form of lanthanum-strontium-cobalt (La-Sr-Co) oxide and a porous ion conducting scaffold that combines chemically assisted electrodeposition and infiltration techniques with a solid oxide fuel cell. It is to provide a manufacturing method.
본 발명의 또다른 목적은 다공성 이온전도 스캐폴드에 란타넘-스트론튬-코발트(La-Sr-Co) 산화물이 형성되어 있는 나노섬유 형태의 란타넘-스트론튬-코발트 산화물/다공성 이온전도 스캐폴드의 복합 캐소드, 및 상기 복합 캐소드를 포함하는 고체산화물 연료전지를 제공하는 것이다. Another object of the present invention is a composite of a lanthanum-strontium-cobalt oxide / porous ion conduction scaffold in the form of nanofibers in which a lanthanum-strontium-cobalt (La-Sr-Co) oxide is formed on a porous ion conducting scaffold. It is to provide a cathode, and a solid oxide fuel cell comprising the composite cathode.
상기와 같은 목적을 달성하기 위하여, 본 발명은In order to achieve the above object, the present invention
다공성 이온전도 스캐폴드(scaffold)의 표면에 탄소나노튜브를 형성하는 단계; Forming a carbon nanotube on the surface of the porous ion conducting scaffold;
상기 탄소나노튜브 상에 란타넘-코발트(La-Co) 산화물을 전착(electrodeposition)시키는 단계;Electrodeposition of a lanthanum-cobalt (La-Co) oxide on the carbon nanotubes;
상기 스캐폴드를 열처리하여 탄소나노튜브를 제거하는 단계;Heat-treating the scaffold to remove carbon nanotubes;
상기 스캐폴드에 스트론튬(Sr)을 침윤(infiltration)시키는 단계; 및Infiltration of strontium (Sr) into the scaffold; And
상기 스캐폴드를 열처리하여 나노섬유의 란타넘-스트론튬-코발트(La-Sr-Co) 산화물을 형성하는 단계;Heat-treating the scaffold to form a lanthanum-strontium-cobalt (La-Sr-Co) oxide of nanofibers;
를 포함하는 고체산화물 연료전지 공기극의 제조방법을 제공한다.It provides a method for manufacturing a cathode of a solid oxide fuel cell comprising a.
상기 제조방법에 있어서, 상기 다공성 이온전도 스캐폴드는,In the above method, the porous ion conducting scaffold,
GDC(Gd-doped ceria) 분말, 용매, 결합제 및 기공형성제를 혼합한 GDC 잉크를 제조하는 단계; 및Preparing a GDC ink in which Gd-doped ceria (GDC) powder, a solvent, a binder, and a pore-forming agent are mixed; And
상기 GDC 잉크를 ScCeSZ 전해질 층 위에 스크린 인쇄한 후 열처리하는 단계; 를 포함하는 방법으로 제조될 수 있다.Heat-treating the GDC ink after screen printing on the ScCeSZ electrolyte layer; It may be prepared by a method comprising a.
상기 제조방법에 있어서, 상기 탄소나노튜브는In the above manufacturing method, the carbon nanotube is
전이금속 나노 입자를 상기 스캐폴드에 침투 분산시키는 단계; 및Permeating and dispersing transition metal nanoparticles into the scaffold; And
탄소 소스를 공급하여 상기 전이금속 나노 입자로부터 탄소나노튜브를 성장시키는 단계;를 포함하는 방법으로 형성될 수 있다.Growing carbon nanotubes from the transition metal nanoparticles by supplying a carbon source; may be formed by a method comprising a.
상기 제조방법에 있어서, 상기 스트론튬의 침윤은In the above manufacturing method, the infiltration of the strontium is
질산 스트론튬 분말을 용매에 첨가하여 용해시켜 질산 스트론튬 용액을 제조하는 단계; 및Preparing a solution of strontium nitrate by dissolving strontium nitrate powder by adding it to a solvent; And
상기 질산 스트론튬 용액을 란타넘-코발트 산화물로 증착된 스캐폴드에 첨가하여 침윤시킨 후 건조시키는 단계;를 포함하는 방법으로 수행될 수 있다.And adding the strontium nitrate solution to a scaffold deposited with lanthanum-cobalt oxide, followed by infiltrating and drying.
또한, 본 발명은In addition, the present invention
다공성 이온전도 스캐폴드; 및Porous ion conducting scaffolds; And
상기 다공성 이온전도 스캐폴드에 형성된 나노섬유 형태의 LaxSr1 - xCoO3 (여기서, X는 0 < X < 1의 소수);을 포함하는,La x Sr 1 - x CoO 3 in the form of nanofibers formed on the porous ion conducting scaffold (where X is a prime number of 0 <X <1);
고체산화물 연료전지 공기극을 제공한다.A cathode for a solid oxide fuel cell is provided.
상기 고체산화물 연료전지 공기극에 있어서, 상기 다공성 이온전도 스캐폴드는 다공성 GDC(Gd-doped ceria) 스캐폴드일 수 있다.In the cathode of the solid oxide fuel cell, the porous ion conducting scaffold may be a porous Gd-doped ceria (GDC) scaffold.
아울러, 본 발명은In addition, the present invention
상기 본 발명에 따른 공기극;Air cathode according to the present invention;
연료극; 및Anode; And
상기 공기극과 상기 연료극 사이에 구비된 전해질층Electrolyte layer provided between the cathode and the anode
을 포함하는 고체산화물 연료전지를 제공한다.It provides a solid oxide fuel cell comprising a.
상기 고체산화물 연료전지에 있어서, 상기 연료극은 NiO-ScCeSZ 또는 NiO-YSZ으로 형성될 수 있다.In the solid oxide fuel cell, the anode may be formed of NiO-ScCeSZ or NiO-YSZ.
상기 고체산화물 연료전지에 있어서, 상기 전해질층은 이트륨 안정화 지르코니아, 스칸디움 안정화 지르코니아 및 가돌리움 도핑된 세리아 중 적어도 하나로 형성될 수 있다.In the solid oxide fuel cell, the electrolyte layer may be formed of at least one of yttrium stabilized zirconia, scandium stabilized zirconia, and gadolium doped ceria.
본 발명에 따른 나노섬유 형태의 La1 - xSrxCoO3/GDC 복합 캐소드의 새로운 제조 방법은 기존의 소결에 비해 낮은 제조 온도(약 900℃)를 사용하며, 이는 ScCeSZ 전해질로 2차 상을 형성하는 것을 피할 수 있다. The new manufacturing method of La 1 - x Sr x CoO 3 / GDC composite cathode in the form of nanofibers according to the present invention uses a lower manufacturing temperature (approximately 900 ° C) compared to conventional sintering, which uses the secondary phase as the ScCeSZ electrolyte. Formation can be avoided.
또한, 본 발명에 따른 제조 방법은 La1 - xSrxCoO3 로딩에 대한 우수한 제어를 제공하고, 단일 전착 단계에서 원하는 로딩을 달성할 수 있다. In addition, the manufacturing method according to the present invention provides excellent control over La 1 - x Sr x CoO 3 loading, and can achieve the desired loading in a single electrodeposition step.
또한, 본 발명에 따른 새로운 나노섬유 형태의 복합 캐소드는 넓은 표면적을 제공할 수 있고, 나노 다공성 구조를 통한 산화제의 수송을 도울 수 있다. In addition, the composite cathode in the form of a new nanofiber according to the present invention can provide a large surface area and help transport the oxidant through the nanoporous structure.
또한, 본 발명에 따른 새로운 제조 기술로 생산된 애노드 지원 버튼 셀은 가습된 수소를 연료로 사용하면서 높은 전기화학적 성능(750℃에서 약 613 mW cm- 2)을 나타낼 수 있다.In addition, the anode-assisted button cell produced by the new manufacturing technology according to the present invention can exhibit high electrochemical performance (about 613 mW cm - 2 at 750 ° C) while using humidified hydrogen as a fuel.
도 1은 SOFC용 나노섬유 LaxSr1 - xCoO3/GDC 복합 캐소드 제조 공정의 개략도를 보여주는 그림이다.1 is a view showing a schematic diagram of a manufacturing process of nanofiber La x Sr 1 - x CoO 3 / GDC composite cathode for SOFC.
도 2는 애노드가 지지된 SOFC의 SEM 이미지를 보여주는 그림이다.2 is a view showing an SEM image of the anode-supported SOFC.
도 3은 (a) 원시의, (b) Co 나노입자 증착된, 및 (c) CNT 변형 GDC 스캐 폴드의 SEM 이미지를 보여주는 그림이다.FIG. 3 is an SEM image of (a) primitive, (b) Co nanoparticle deposited, and (c) CNT modified GDC scaffold.
도 4는 (a) 나노섬유 LaxSr1 - xCoO3/GDC 및 (b) 기존 LSC/GDC 복합 캐소드의 SEM 이미지를 보여주는 그림이다.FIG. 4 is a view showing SEM images of (a) nanofiber La x Sr 1 - x CoO 3 / GDC and (b) a conventional LSC / GDC composite cathode.
도 5는 (a) 3.0, (b) 3.2, (c) 3.4, (d) 3.6 및 (e) 3.8 mM의 La3 +를 함유한 수용액으로부터 La 및 Co 증착 후 GDC 스캐폴드의 EDS 분석 결과를 보여주는 그림이다.Figure 5 (a) 3.0, (b) 3.2, (c) 3.4, (d) 3.6 and (e) post-deposition La and Co from an aqueous solution containing the La 3 + of 3.8 mM of EDS analysis of the GDC scaffold It is a picture showing.
도 6은 최종적으로 제조된 나노섬유 LaxSr1 - xCoO3/GDC 캐소드의 XRD 분석 결과를 보여주는 그림이다. 6 is a view showing the results of XRD analysis of the finally produced nanofiber La x Sr 1 - x CoO 3 / GDC cathode.
도 7은 (a) 나노섬유 LaxSr1 - xCoO3/GDC 및 (b) 기존 LSC/GDC 복합 캐소드를 가지는 SOFC의 편광 곡선을 보여주는 그림이다. 7 is a view showing a polarization curve of (FC) SOFC having (a) nanofiber La x Sr 1 - x CoO 3 / GDC and (b) a conventional LSC / GDC composite cathode.
도 8은 (a) 나노섬유 LaxSr1 - xCoO3/GDC 및 (b) 기존 LSC/GDC 복합 캐소드를 가지는 SOFC의 전기 화학적 임피던스 플롯을 보여주는 그림이다. FIG. 8 is a graph showing the electrochemical impedance plot of SOFC having (a) nanofiber La x Sr 1 - x CoO 3 / GDC and (b) a conventional LSC / GDC composite cathode.
본 발명의 이점 및 특징, 그리고 그것들을 달성하는 방법은 첨부되는 도면과 함께 상세하게 후술되어 있는 실시예를 참조하면 명확해질 것이다. 그러나 본 발명은 여기서 설명되는 실시예들에 한정되지 않고 다른 형태로 구체화될 수도 있다. 오히려, 여기서 소개되는 실시예들은 개시된 내용이 철저하고 완전해질 수 있도록 그리고 당업자에게 본 발명의 사상이 충분히 전달될 수 있도록 하기 위해 제공되는 것이다. Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed contents are thorough and complete and that the spirit of the present invention is sufficiently conveyed to those skilled in the art.
본 명세서에서 사용한 용어는 단지 특정한 실시예를 설명하기 위해 사용된 것으로, 본 발명을 한정하려는 의도가 아니다. 단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한, 복수의 표현을 포함한다. 본 명세서에서, "포함하다" 또는 "가지다" 등의 용어는 명세서상에 기재된 특징, 숫자, 단계, 동작, 구성요소, 부분품 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 부분품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.The terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "include" or "have" are intended to designate the presence of features, numbers, steps, actions, elements, parts or combinations thereof described in the specification, but one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.
다르게 정의되지 않는 한, 기술적이거나 과학적인 용어를 포함해서 여기서 사용되는 모든 용어들은 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자에 의해 일반적으로 이해되는 것과 동일한 의미가 있다. 일반적으로 사용되는 사전에 정의되어 있는 것과 같은 용어들은 관련 기술의 문맥상 가지는 의미와 일치하는 의미가 있는 것으로 해석되어야 하며, 본 명세서에서 명백하게 정의하지 않는 한, 이상적이거나 과도하게 형식적인 의미로 해석되지 않는다.Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined herein. Does not.
이하, 본 발명을 상세히 설명한다.Hereinafter, the present invention will be described in detail.
본 발명은 고체 산화물 연료 전지에 화학적으로 보조된 전착 및 침투 기술을 결합한 나노섬유 형태의 란타넘-스트론튬-코발트(La-Sr-Co) 산화물과 다공성 이온전도 스캐폴드(scaffold)의 복합 캐소드의 제조 방법을 제공한다.The present invention is to prepare a composite cathode of a nanofiber form of lanthanum-strontium-cobalt (La-Sr-Co) oxide and a porous ion conducting scaffold that combine chemically assisted electrodeposition and infiltration techniques with a solid oxide fuel cell. Provide a method.
구체적으로, 상기 제조 방법은 Specifically, the manufacturing method
i) 다공성 이온전도 스캐폴드(scaffold)의 표면에 탄소나노튜브를 형성하는 단계; i) forming a carbon nanotube on the surface of the porous ion conducting scaffold;
ii) 상기 탄소나노튜브 상에 란타넘-코발트(La-Co) 산화물을 전착(electrodeposition)시키는 단계; ii) electrodeposition of a lanthanum-cobalt (La-Co) oxide on the carbon nanotube;
iii) 상기 스캐폴드를 열처리하여 탄소나노튜브를 제거하는 단계; iii) heat-treating the scaffold to remove carbon nanotubes;
iv) 상기 스캐폴드에 스트론튬(Sr)을 침윤(infiltration)시키는 단계; 및 iv) infiltration of strontium (Sr) into the scaffold; And
v) 상기 스캐폴드를 열처리하여 나노섬유의 란타넘-스트론튬-코발트(La-Sr-Co) 산화물을 형성하는 단계;를 포함한다.v) heat-treating the scaffold to form a lanthanum-strontium-cobalt (La-Sr-Co) oxide of nanofibers.
상기 제조 방법에 있어서, 상기 단계 i)에서 다공성 이온전도 스캐폴드는 다공성 지르코니아-세리아 이온전도 스캐폴드 또는 다공성 세리아-가돌리늄 이온전도 스캐폴드일 있다.In the above manufacturing method, the porous ion conducting scaffold in step i) may be a porous zirconia-ceria ion conducting scaffold or a porous ceria-gadolinium ion conducting scaffold.
상기 다공성 이온전도 스캐폴드는 GDC(Gd-doped ceria) 분말, 용매, 결합제 및 기공형성제를 혼합한 GDC 잉크를 제조하는 단계; 및, 상기 GDC 잉크를 ScCeSZ 전해질 층 위에 스크린 인쇄한 후 열처리하는 단계;를 포함하는 방법으로 제조되는 것이 바람직하다.The porous ion conductive scaffold comprises the steps of preparing a GDC ink in which Gd-doped ceria (GDC) powder, a solvent, a binder, and a pore-forming agent are mixed; And, the GDC ink is screen-printed on the ScCeSZ electrolyte layer, followed by heat treatment; it is preferably prepared by a method comprising a.
상기 전착은 도전성 표면상에서만 수행될 수 있으므로, 다공성 스캐폴드의 표면은 전착 이전에 도전성을 갖도록 처리되어야 한다. 본 발명의 실시예에서는, 전착에 기반한 경로, 예를 들어, 화학보조전착(chemically assisted electrodeposition, CAED)에 의해, "나노 섬유" LaCoO3 (LCO) 페로브스카이트를 고체산화물 연료전지의 공기극 촉매로 형성하였다.Since the electrodeposition can only be performed on a conductive surface, the surface of the porous scaffold must be treated to have conductivity before electrodeposition. In an embodiment of the present invention, a "nano fiber" LaCoO 3 (LCO) perovskite is cathodic catalyst of a solid oxide fuel cell by a route based on electrodeposition, for example, chemically assisted electrodeposition (CAED). Formed with.
상기 탄소나노튜브 형성은 전이금속 나노 입자를 상기 스캐폴드에 침투 분산시키는 단계; 및, 탄소 소스를 공급하여 상기 전이금속 나노 입자로부터 탄소나노튜브를 성장시키는 단계;를 포함하는 방법으로 제조되는 것이 바람직하다. 본 발명의 실시예에서는, 다공질의 지르코니아계 이온전도 스캐폴드 상에 C2H4를 촉매 화학기상증착(catalytic chemical vapor deposition, CCVD)하여 탄소나노튜브를 형성하였다. 촉매 화학기상증착법은 높은 신뢰성과 고순도를 구현할 수 있다. The formation of the carbon nanotubes comprises: dispersing and dispersing transition metal nanoparticles in the scaffold; And supplying a carbon source to grow carbon nanotubes from the transition metal nanoparticles. In an embodiment of the present invention, carbon nanotubes were formed by catalytic chemical vapor deposition (CCVD) of C 2 H 4 on a porous zirconia-based ion conductive scaffold. Catalytic chemical vapor deposition can achieve high reliability and high purity.
상기 전이금속 나노 입자는 Fe, Ni 또는 Co 등을 사용할 수 있다. 본 발명의 실시예에서는, 탄소나노튜브 성장의 촉매를 제공하기 위해, 코발트 질산염 전구체 용액을 다공성 이온전도 스캐폴드로 함침시켰다. Fe, Ni, or Co may be used as the transition metal nanoparticles. In an embodiment of the present invention, a cobalt nitrate precursor solution was impregnated with a porous ion conducting scaffold to provide a catalyst for carbon nanotube growth.
상기 제조 방법에 있어서, 상기 단계 ii)에서 탄소나노튜브 상에 란타넘-코발트(La-Co) 산화물을 전착한다. 본 발명의 실시예에서는, 란타늄-코발트 수산화물(La-Co-OH)을 화학보조전착(chemically assisted electrodeposition, CAED)에 의해 탄소나노튜브 상에 증착시켰다.In the above manufacturing method, in step ii), a lanthanum-cobalt (La-Co) oxide is electrodeposited on a carbon nanotube. In an embodiment of the present invention, lanthanum-cobalt hydroxide (La-Co-OH) was deposited on carbon nanotubes by chemically assisted electrodeposition (CAED).
상기 제조 방법에 있어서, 상기 단계 iii)에서 스캐폴드를 열처리하여 탄소나노튜브를 제거한다. 상기 열처리는 700 내지 900℃의 저온 열처리가 바람직하다. 이때, 900℃ 이하의 온도에서 스캐폴드를 열처리하여 열변환을 통해 페로브스카이트형의 LaCoO3(LCO)를 형성할 수 있다. 열변환 동안, 탄소나노튜브는 완전히 분해되어, 이온전도 스캐폴드의 내부에는 섬유상의 LCO 구조만이 남는다. 종래 기술에 따라 900℃ 초과의 고온 소결을 진행하는 경우, LaCoO3-계 물질들이 지르코니아계 전해질과 쉽게 반응하여, 절연성 파이로클로르(pychlore)상을 형성하게 된다. 그러나 본 발명이 실시예에 따르면, 900℃ 이하의 저온 열처리 공정에 의해서, 절연성 상의 형성이 억제된다. In the above method, the scaffold is heat-treated in step iii) to remove carbon nanotubes. The heat treatment is preferably a low-temperature heat treatment of 700 to 900 ℃. At this time, the scaffold may be heat treated at a temperature of 900 ° C. or less to form perovskite type LaCoO 3 (LCO) through thermal conversion. During the heat conversion, the carbon nanotubes are completely decomposed, leaving only the fibrous LCO structure inside the ion conducting scaffold. When performing high-temperature sintering of more than 900 ° C according to the prior art, LaCoO 3 -based materials easily react with the zirconia-based electrolyte to form an insulating pyrochlore phase. However, according to the embodiment of the present invention, formation of an insulating phase is suppressed by a low temperature heat treatment process of 900 ° C or less.
상기 제조 방법에 있어서, 상기 단계 iv)에서 스캐폴드에 스트론튬(Sr)을 침윤(infiltration)시킨다. 상기 스트론튬의 침윤은 질산 스트론튬 분말을 용매에 첨가하여 용해시켜 질산 스트론튬 용액을 제조하는 단계; 및, 상기 질산 스트론튬 용액을 란타넘-코발트 산화물로 증착된 스캐폴드에 첨가하여 침윤시킨 후 건조시키는 단계;를 포함하는 방법으로 수행되는 것이 바람직하다. In the above method, strontium (Sr) is infiltrated into the scaffold in step iv). Infiltrating the strontium is dissolved by adding strontium nitrate powder to a solvent to prepare a strontium nitrate solution; And, it is preferred that the strontium nitrate solution is added to the scaffold deposited with a lanthanum-cobalt oxide, followed by infiltration and drying.
상기 제조 방법에 있어서, 상기 단계 v)에서 스캐폴드를 열처리하여 나노섬유 형태의 란타넘-스트론튬-코발트(La-Sr-Co) 산화물을 형성시킨다. 상기 열처리는 800 내지 1000℃의 저온 열처리가 바람직하다. 이때, 1000℃ 초과의 고온 소결을 진행하는 경우, ScCeSZ 전해질로 2차 상을 형성하기 때문에 1000℃ 이하의 저온 열처리 공정에 의해서 이런 2차 상 형성을 피할 수 있다.In the above method, the scaffold is heat-treated in step v) to form a nanofiber lanthanum-strontium-cobalt (La-Sr-Co) oxide. The heat treatment is preferably a low-temperature heat treatment of 800 to 1000 ℃. At this time, when performing high-temperature sintering of more than 1000 ° C, since the secondary phase is formed with the ScCeSZ electrolyte, such secondary phase formation can be avoided by a low-temperature heat treatment process of 1000 ° C or lower.
본 발명의 한가지 실시예에서는 고체 산화물 연료 전지에 화학적으로 보조된 전착 및 침투 기술을 결합하여, La0 . 6CoO3를 다공성 GDC 지지체에 화학적으로 전착한 후 900℃에서 열처리한 다음 Sr을 침윤시켜 La1 - xSrxCoO3 상을 생성시킴으로써, 나노 섬유 형태의 La1 - xSrxCoO3(여기서, X는 0 < X < 1의 소수)-GDC 복합 캐소드를 제조하였다.In one embodiment of the present invention, a chemically assisted electrodeposition and penetration technique is combined with a solid oxide fuel cell, such that La 0 . 6 after the CoO 3 a chemical deposition with a porous GDC the support followed by heat treatment at 900 ℃ by infiltration Next Sr La 1 - x Sr x CoO by generating a three-phase, nanofibers, in the form of La 1 - x Sr x CoO 3 (where , X is 0 <X <1 prime) -GDC composite cathode was prepared.
구체적으로, 본 발명의 한가지 실시예에서는 a) 애노드 지지 버튼 셀의 고밀도 ScCeSZ 전해질 상에 30 중량% PMMA 기공 형성제를 함유하는 GDC 잉크를 스크린 인쇄 및 1300℃ 소결에 의해 고 다공성 GDC 스캐폴드를 제조한 후, b) 탄소원으로서 에틸렌을 사용하여 탄소 750℃의 촉매 화학 기상 증착에 의해 CNT 성장을 위한 시드로서 작용하기 위한 0.5M 질산 코발트 용액을 다공성 GDC 스캐폴드 내 침투시킨 다음, c) La(NO3)3-6H2O 및 Co(NO3)2-6H2O를 함유하는 수계 전해질로부터의 La 및 Co의 화학적 보조 전착에 의한 La0 . 6CoO3을 전착한 후, d) 전착된 GDC 스캐폴드로부터 CNT를 제거하기 위해, 증착된 GDC 스캐폴드를 750℃에서 5시간 동안 열처리한 다음, e) 질산 스트론튬 분말을 에틸렌 글리콜에 완전히 용해한 질산 스트론튬 용액을 La0 . 6CoO3로 증착된 GDC 스캐폴드에 첨가하고 95℃의 오븐에서 완전히 건조시킨 후, f) 버튼 셀을 노(furnace)에 넣고 900℃에서 열처리하여 나노섬유 형태의 La1 -xSrxCoO3를 형성하였다.Specifically, in one embodiment of the present invention, a) GDC ink containing 30% by weight PMMA pore former on a high density ScCeSZ electrolyte of an anode support button cell is screen printed and sintered at 1300 ° C. to produce a high porosity GDC scaffold. After that, b) a 0.5 M cobalt nitrate solution to act as a seed for CNT growth was penetrated into a porous GDC scaffold by catalytic chemical vapor deposition of 750 ° C. carbon using ethylene as the carbon source, and then c) La (NO 3) 3 -6H 2 O and Co (NO 3) 2 -6H by chemical auxiliary electrodeposition of La and Co from an aqueous electrolyte containing La 2 O 0. 6 After electrodeposition of CoO 3 , d) to remove CNTs from the electrodeposited GDC scaffold, the deposited GDC scaffold was heat treated at 750 ° C. for 5 hours, and then e) nitric acid in which strontium nitrate powder was completely dissolved in ethylene glycol. The strontium solution was La 0 . 6 After adding to the GDC scaffold deposited with CoO 3 and completely drying in an oven at 95 ° C., f) Put the button cell in a furnace and heat-treat at 900 ° C. to form a nanofiber La 1 -x Sr x CoO 3 Formed.
본 발명에 따른 나노 섬유 형태의 La1 - xSrxCoO3(여기서, X는 0 < X < 1의 소수)-GDC 복합 캐소드의 제조 방법에 대한 개략도는 도 1에 나타난 바와 같다. A schematic diagram of a method for manufacturing a La 1 - x Sr x CoO 3 in a nanofiber form according to the present invention (where X is a prime number of 0 <X <1) -GDC composite cathode is shown in FIG. 1.
본 발명에 따른 나노 섬유 형태의 La1 - xSrxCoO3(여기서, X는 0 < X < 1의 소수)-GDC 복합 캐소드의 새로운 제조 방법은 기존의 소결에 비해 낮은 제조 온도를 사용하여 ScCeSZ 전해질로 2차 상을 형성하는 것을 피할 수 있고, La1 - xSrxCoO3 로딩에 대한 우수한 제어를 제공하며, 단일 전착 단계에서 원하는 로딩을 달성할 수 있다. The new method of manufacturing La 1 - x Sr x CoO 3 in the nanofiber form according to the present invention (where X is a prime number of 0 <X <1) -GDC composite cathode uses ScCeSZ using a lower manufacturing temperature than conventional sintering. The formation of a secondary phase with the electrolyte can be avoided, providing good control over La 1 - x Sr x CoO 3 loading and achieving the desired loading in a single electrodeposition step.
또한, 본 발명에 따른 나노 섬유 형태의 La1 - xSrxCoO3(여기서, X는 0 < X < 1의 소수)-GDC 복합 캐소드는 넓은 표면적을 제공할 수 있으며, 나노 다공성 구조를 통한 산화제의 수송을 도울 수 있으며, 상기 캐소드를 사용한 애노드 지지 버튼 셀은 가습된 수소를 연료로 사용하면서 높은 전기 화학 성능(750℃에서 613mW cm-2)을 나타낼 수 있다.In addition, La 1 - x Sr x CoO 3 (where X is a prime number of 0 <X <1) -GDC composite cathode in the form of nanofibers according to the present invention can provide a large surface area, and an oxidizing agent through a nanoporous structure The anode support button cell using the cathode may exhibit high electrochemical performance (613 mW cm −2 at 750 ° C.) while using humidified hydrogen as a fuel.
또한, 본 발명은 상기 본 발명에 따른 제조 방법으로 제조된 고체산화물 연료전지 공기극을 제공한다.In addition, the present invention provides a cathode of a solid oxide fuel cell manufactured by the manufacturing method according to the present invention.
구체적으로, 본 발명은 다공성 이온전도 스캐폴드; 및, 상기 다공성 이온전도 스캐폴드에 형성된 나노섬유 형태의 LaxSr1 - xCoO3 (여기서, X는 0 < X < 1의 소수);을 포함하는 고체산화물 연료전지 공기극을 제공한다.Specifically, the present invention is a porous ion conducting scaffold; And La x Sr 1 - x CoO 3 (where X is a prime number of 0 <X <1) in the form of nanofibers formed on the porous ion conducting scaffold.
이때, 상기 다공성 이온전도 스캐폴드는 다공성 GDC(Gd-doped ceria) 스캐폴드인 것이 바람직하다In this case, the porous ion conducting scaffold is preferably a porous Gd-doped ceria (GDC) scaffold.
아울러, 본 발명은 상기 본 발명에 따른 고체산화물 연료전지 공기극을 포함하는 고체산화물 연료전지를 제공한다.In addition, the present invention provides a solid oxide fuel cell including the cathode of the solid oxide fuel cell according to the present invention.
구체적으로, 본 발명은 상기 본 발명에 따른 공기극; 연료극; 및, 상기 공기극과 상기 연료극 사이에 구비된 전해질층;을 포함하는 고체산화물 연료전지를 제공한다.Specifically, the present invention is the air electrode according to the present invention; Anode; And an electrolyte layer provided between the air electrode and the fuel electrode.
이때, 상기 연료극은 NiO-ScCeSZ 또는 NiO-YSZ으로 형성될 수 있다.At this time, the anode may be formed of NiO-ScCeSZ or NiO-YSZ.
이때, 상기 전해질층은 이트륨 안정화 지르코니아, 스칸디움 안정화 지르코니아 및 가돌리움 도핑된 세리아 중 적어도 하나로 형성될 수 있다.In this case, the electrolyte layer may be formed of at least one of yttrium stabilized zirconia, scandium stabilized zirconia, and gadolium doped ceria.
이하, 본 발명을 하기 실시예 및 실험예에 의해 상세히 설명한다.Hereinafter, the present invention will be described in detail by the following examples and experimental examples.
단, 하기 실시예 및 실험예는 본 발명을 예시하는 것일 뿐, 본 발명의 내용이 하기 실시예 및 실험예에 의해 한정되는 것은 아니다.However, the following examples and experimental examples are merely illustrative of the present invention, and the contents of the present invention are not limited by the following examples and experimental examples.
<실시예 1> 나노섬유 La1 - xSrxCoO3/GDC 복합 캐소드의 제조<Example 1> Preparation of nanofiber La 1 - x Sr x CoO 3 / GDC composite cathode
<1-1> 연료극 지지 버튼 셀의 제조 <1-1> Preparation of anode support button cell
NiO(Konjundo Chemical Laboratory, Japan) 및 YSZ(Fuel Cell Materials, USA) (56:44) 분말을 용매로서 에탄올을 사용하고 12 중량% 활성 탄소 기공 형성제와 함께 볼 밀링하여 혼합하였다. 혼합된 분말을 오븐에서 건조시키고 둥근 녹색 디스크로 압축하여 버튼 셀을 위한 연료극 지지체로 사용하였다. 녹색 연료극 지지체는 공기 중에서 5시간 동안 1100℃에서 예비 소결되었다. NiO (Konjundo Chemical Laboratory, Japan) and YSZ (Fuel Cell Materials, USA) (56:44) powders were mixed by ball milling with 12% by weight activated carbon pore former using ethanol as a solvent. The mixed powder was dried in an oven and compressed into a round green disk to serve as an anode support for the button cell. The green anode support was pre-sintered at 1100 ° C. for 5 hours in air.
다음 단계에서, NiO-ScCeSZ 연료극 기능 층과 ScCeSZ 전해질 층을 예비 소결된 연료극 지지체 위에 침지시킨 후, 1400℃에서 5시간 동안 공기 중에서 소성시켰다. GDC 분말(Fuel Cell Materials USA)을 용매, 결합제 및 기공 형성제로서 각각 α-테르피놀(α-terpinol), 에틸 셀룰로오스 및 PMMA(3 μm)를 적당량 첨가하여 다공성 GDC 스캐폴드를 제조하기 위한 GDC 잉크를 제조하였다. GDC 스캐폴드 잉크의 성분은 유성 원심 혼합기(Thinky SR-500)에서 혼합되었다. 그런 다음, GDC 잉크를 고밀도 ScCeSZ 전해질 층 위에 스크린 인쇄한 다음, 공기 중에서 3시간 동안 1300℃에서 소결하였다.In the next step, the NiO-ScCeSZ anode functional layer and the ScCeSZ electrolyte layer were immersed on the pre-sintered anode support and calcined in air at 1400 ° C. for 5 hours. GDC ink for producing porous GDC scaffolds by adding appropriate amounts of α-terpinol, ethyl cellulose and PMMA (3 μm) as GDC powder (Fuel Cell Materials USA) as solvent, binder and pore former, respectively. Was prepared. The components of the GDC scaffold ink were mixed in an oily centrifugal mixer (Thinky SR-500). The GDC ink was then screen printed onto a high density ScCeSZ electrolyte layer, and then sintered in air at 1300 ° C. for 3 hours.
<1-2> CNT 증착(deposition)<1-2> CNT deposition
탄소나노튜브(CNT) 네트워크는 La0 . 6CoO3의 화학적으로 보조된 전착(electrodeposition)을 위한 전도성 표면을 제공하기 위해, 촉매 화학 기상 증착(catalytic vapor deposition)에 의해 GDC 스캐폴드 상에 증착되었다. 그렇게 하기 위해, 0.5M 질산 코발트 수용액을 다공성 GDC 발판에 침투시켜 CNT의 성장을 위한 Co 나노 입자를 형성시켰다. 버튼 셀을 강철 지그(steel jig) 내로 밀봉하되 GDC 스캐폴드만 주위 환경에 노출되도록 하였다. 버튼 셀을 포함하는 강철 지그를 튜브로에 넣고 흐르는 질소 분위기에서 750℃로 가열하였다. 그 후, 질소 가스를 C2H4로 대체하고 가스 흐름을 5분간 유지하여 그동안 탄소는 상호 연결된 CNT 네트워크의 형태로 증착시켰다.Carbon nanotube (CNT) network is La 0 . 6 CoO 3 was deposited on the GDC scaffold by catalytic vapor deposition to provide a conductive surface for chemically assisted electrodeposition. To do so, 0.5 M cobalt nitrate aqueous solution was infiltrated into the porous GDC scaffold to form Co nanoparticles for the growth of CNTs. The button cell was sealed into a steel jig but only the GDC scaffold was exposed to the surrounding environment. The steel jig including the button cell was placed in a tube furnace and heated to 750 ° C in a flowing nitrogen atmosphere. Thereafter, nitrogen gas was replaced with C 2 H 4 and the gas flow was maintained for 5 minutes, during which carbon was deposited in the form of an interconnected CNT network.
<1-3> La0 . 6CoO3의 전착(electrodeposition)<1-3> La 0 . 6 Electrodeposition of CoO 3
La0 . 6CoO3의 전착을 위하여, La(NO3)3-6H2O (99.99%, Sigma Aldrich), Co(NO3)2-6H2O (99.99%, Sigma Aldrich)와 KNO3 (99.99%, Sigma Aldrich)를 준비하였다. LaCoO3의 전착에 사용된 셋업은 두 개의 구획 전기 화학 셀로 구성된다. 상기 전기 화학 셀의 두 개의 구획은 이온 교환막(APS4, Asahi Glass)에 의해 분리되었다. La 0 . For electrodeposition of 6 CoO 3 , La (NO 3 ) 3 -6H 2 O (99.99%, Sigma Aldrich), Co (NO 3 ) 2 -6H 2 O (99.99%, Sigma Aldrich) and KNO 3 (99.99%, Sigma Aldrich) was prepared. The setup used for electrodeposition of LaCoO 3 consists of two compartment electrochemical cells. The two compartments of the electrochemical cell were separated by an ion exchange membrane (APS4, Asahi Glass).
구획(1)은 버튼 셀(작업 전극) 및 La(NO3)3-6H2O 및 Co(NO3)2-6H2O을 포함하는 수계 전해질을 포함하였다. 원하는 화학 양론적 증착, 즉 0.6 : 1의 La 대 Co 비율을 얻기 위해, Co2 + 비는 5 mM으로 고정하고, La3 +의 양은 수계 전해질에서 3, 3.2, 3.4, 3.6 및 3.8 mM으로 다양하게 하였다. 3, 3.2, 3.4, 3.6 및 3.8 mM의 La3 +를 포함하는 수성 전해질을 각각 LC1, LC2, LC3, LC4 및 LC5로 명명하였다.The compartment 1 contained a button cell (working electrode) and an aqueous electrolyte comprising La (NO 3 ) 3 -6H 2 O and Co (NO 3 ) 2 -6H 2 O. Desired stoichiometric deposition, that is from 0.6: to obtain La for Co ratio of 1, Co 2 + ratio is fixed at 5 mM, and in a quantity-aqueous electrolyte of the La 3 + 3, 3.2, 3.4, 3.6, and 3.8 mM of various Was made. 3, 3.2, 3.4, an aqueous electrolyte containing La 3 + 3.6 and 3.8 mM, respectively named as LC1, LC2, LC3, LC4 and LC5.
화학적으로 보조된 전착 실험의 상세한 조건은 하기 표 1에 나타내었다. The detailed conditions of the chemically assisted electrodeposition experiment are shown in Table 1 below.
La0 . 6CoO3의 화학적 보조 전착에 대한 실험 조건La 0 . 6 Experimental conditions for chemical assisted electrodeposition of CoO 3
No.No. 전류 밀도(mA/cm2)Current density (mA / cm 2 ) 란타넘농도(mM)Lanthanum concentration (mM) 코발트농도(mM)Cobalt concentration (mM) 칼륨농도(mM)Potassium concentration (mM) 소성온도(℃)Firing temperature (℃)
LC1LC1 1One 3.03.0 55 7.477.47 750750
LC2LC2 3.23.2 7.677.67
LC3LC3 3.43.4 7.877.87
LC4LC4 3.63.6 8.078.07
LC5LC5 3.83.8 8.278.27
버튼 셀은 탄소 코팅된 GDC 지지체(작업 전극)만이 질산 용액에 노출되도록 유기 고분자 페인트를 사용하여 마스킹하였다. The button cell was masked using an organic polymer paint so that only the carbon-coated GDC support (working electrode) was exposed to the nitric acid solution.
구획 (2)는 Pt 메쉬(상대 전극) 및 KNO3의 수계 전해질을 포함하였다. 금속 이온의 농도는 두 개의 구획에서 Section (2) contained a Pt mesh (relative electrode) and an aqueous electrolyte of KNO 3 . The concentration of metal ions in two compartments
동일하게 하였다. 전착은 작업 전극을 캐소드로 분극(cathodically polarizing)시킴으로써 정전 보상적으로 수행하였다. 전착 공정을 완료한 후 버튼 셀을 전해질로부터 제거하고, 탈 이온수로 세척하여 질산염을 제거하였다. 그런 다음, 버튼 셀을 공기 중에서 5시간 동안 750℃에서 열처리하여 CNT를 제거하였다.The same was done. Electrodeposition was electrostatically compensated by cathodically polarizing the working electrode. After the electrodeposition process was completed, the button cell was removed from the electrolyte, and nitrate was removed by washing with deionized water. Then, the button cells were heat treated at 750 ° C. in air for 5 hours to remove CNTs.
<1-4> 스트론튬 침윤(infiltration)<1-4> Strontium infiltration
용매로서 에틸렌 글리콜을 사용하여 스트론튬 용액을 제조하였다. 상기 용액은 고온의 교반 플랫 상에서 자기 막대를 사용하여 교반하면서 질산 스트론튬 분말을 에틸렌 글리콜에 서서히 첨가함으로써 제조하였다. 질산 스트론튬의 완전한 용해를 위해 에틸렌 글리콜을 100℃까지 가열하였다. 질산 스트론튬 용액의 농도는 GDC 스캐폴드에 증착된 La0 . 6CoO3의 양에 따라 조정되었다. 뜨거운 질산 스트론튬 용액을 단일 침윤(single infiltration) 하에 있는 La0 . 6CoO3로 증착된 GDC 스캐폴드에 첨가하였다. 95℃의 오븐에서 완전히 건조시킨 후, 버튼 셀을 노(furnace)에 넣고 900℃에서 열처리하여 나노섬유성 LaxSr1-xCoO3를 형성시켰다.A strontium solution was prepared using ethylene glycol as the solvent. The solution was prepared by slowly adding strontium nitrate powder to ethylene glycol while stirring using a magnetic rod on a hot stir flat. Ethylene glycol was heated to 100 ° C. for complete dissolution of strontium nitrate. The concentration of the strontium nitrate solution was La 0 deposited on the GDC scaffold . 6 Adjusted according to the amount of CoO 3 . La 0 under a single infiltration of hot strontium nitrate solution . 6 was added to the GDC scaffold deposited with CoO 3 . After drying completely in an oven at 95 ° C, the button cell was placed in a furnace and heat-treated at 900 ° C to form nanofibrous La x Sr 1-x CoO 3 .
<비교예 1> 종래의 LSC/GDC 복합 캐소드의 제조 <Comparative Example 1> Preparation of a conventional LSC / GDC composite cathode
스크린 프린팅 및 소결 기술을 사용하여 종래의 LSC/GDC 캐소드를 제조하였다(대한민국 특허출원번호 제10-2017-0159533호 참조). 그렇게 하기 위해, LSC/GDC 스크린 인쇄 잉크는 유성 원심 믹서에서 LSC(Fuel Cell Materials USA), GDC 분말을 적당량의 α- 테르 피놀 및 에틸 셀룰로오스와 혼합하여 제조하였다. 애노드로 지지된 반쪽 전지의 고밀도 ScCeSZ 전해질 위에 LSC/GDC 잉크를 스크린 인쇄하고 1100℃에서 2시간 동안 소결하였다.A conventional LSC / GDC cathode was prepared using screen printing and sintering technology (see Korean Patent Application No. 10-2017-0159533). To do so, LSC / GDC screen printing inks were prepared by mixing LSC (Fuel Cell Materials USA), GDC powder with an appropriate amount of α- terpineol and ethyl cellulose in an oily centrifugal mixer. LSC / GDC ink was screen-printed on the high-density ScCeSZ electrolyte of the half cell supported by the anode and sintered at 1100 ° C for 2 hours.
<실험예 1> 형태(Morphologies) 및 미세구조(Microstructures) 분석 <Experiment 1> Morphologies and Microstructures Analysis
주사 전자 현미경(SEM, NOVA NANOSEM450, FEI)을 사용하여 나노섬유 La1 -xSrxCoO3/GDC 복합 캐소드와 기존의 LSN/GDC 복합 캐소드의 형태를 관찰하였다. The shape of the nanofiber La 1 -x Sr x CoO 3 / GDC composite cathode and the conventional LSN / GDC composite cathode were observed using a scanning electron microscope (SEM, NOVA NANOSEM450, FEI).
애노드 지지 버튼 셀의 SEM 현미경 사진은 도 2에 나타난 바와 같다. 상기 버튼 셀은 NiO/YSZ 지지체, 조밀한 NiO/ScCeSZ 애노드 기능 층, 조밀한 ScCeSZ 전해질 층 및 다공성 GDC 스캐폴드로 구성되어 있었다. 상기 ScCeSZ 전해질 층은 완전히 밀집되어 있고 또한 애노드 기능 층과 GDC 스캐폴드가 잘 연결되어 있었다. GDC 스캐폴드는 균일한 상호 연결된 구형 공극 네트워크로 구성되어 있었다(도 2).The SEM micrograph of the anode support button cell is as shown in FIG. 2. The button cell consisted of a NiO / YSZ support, a dense NiO / ScCeSZ anode functional layer, a dense ScCeSZ electrolyte layer and a porous GDC scaffold. The ScCeSZ electrolyte layer was completely compact and the anode functional layer and GDC scaffold were well connected. The GDC scaffold consisted of a uniform interconnected spherical pore network (Figure 2).
GDC 스캐폴드는 La0 . 6CoO3의 화학적 보조 전착을 위해 전기 전도성을 가져야 한다. 따라서, 상호 연결된 CNT 네트워크가 GDC 스캐폴드 상에 제조되었다. Co, Ni 및 Fe와 같은 전이금속 나노 입자는 CNT의 성장을 위한 촉매 역할을 한다. 본 발명에서 Co는 SOFC 캐소드의 성능을 향상시키는 것으로 보고되기 때문에, CNT의 성장에 사용되었다. Co는 질산 코발트 수용액의 침윤에 의해 GDC 스캐폴드에 도입되었다. Co 나노 입자는 버튼 셀을 가열하는 동안 질산 코발트의 열분해로 형성되었으며(도 3b), 이런 Co 나노 입자는 C2H4 가스로부터 750℃에서 탄소 증착을 위한 시드로 작용하였다. CNT 증착에 의해 변형된 GDC 스캐폴드는 도 3c 및 도 3d에 나타난 바와 같다. 탄소 증착은 GDC 스캐폴드에서 균일하였고, 탄소 증착물은 또한 전해질/ 캐소드 경계면에서 관찰될 수 있었다. CNT로 개질된 GDC 스캐폴드는 전착 공정을 위해 충분히 전도성이 있는 것으로 확인되었다.The GDC scaffold is La 0 . 6 It must have electrical conductivity for chemical assisted electrodeposition of CoO 3 . Thus, interconnected CNT networks were made on the GDC scaffold. Transition metal nanoparticles such as Co, Ni and Fe act as catalysts for the growth of CNTs. Since Co is reported to improve the performance of the SOFC cathode in the present invention, it was used for the growth of CNTs. Co was introduced into the GDC scaffold by infiltration of an aqueous solution of cobalt nitrate. The Co nanoparticles were formed by thermal decomposition of cobalt nitrate while heating the button cell (FIG. 3B), and these Co nanoparticles served as seeds for carbon deposition at 750 ° C. from C 2 H 4 gas. The GDC scaffold modified by CNT deposition is as shown in FIGS. 3C and 3D. Carbon deposition was uniform in the GDC scaffold, and carbon deposits could also be observed at the electrolyte / cathode interface. The GDC scaffold modified with CNTs was found to be sufficiently conductive for the electrodeposition process.
나노섬유 LaxSr1 - xCoO3 캐소드의 형성을 위해, 900℃에서 최종 열처리한 후 GDC 스캐폴드의 SEM 이미지를 확인한 결과, 도 4a에 나타난 바와 같다. 증착은 나노섬유의 수상 돌기의 형태임을 알 수 있었다. 이런 LaxSr1 - xCoO3 캐소드의 독특한 형태는 거대한 삼상계면(Triple Phase Boundary) 때문에 확장된 표면적을 제공하고, 나노 섬유 구조를 통한 산화제의 흐름을 가능하게 하였다. 종래의 LSC/GDC 캐소드는 스크린 인쇄 및 소결 공정에 의해서도 제조되었다. 종래의 LSC/GDC 캐소드의 SEM 이미지는 도 4b에 나타난 바와 같다. 종래의 LSC/GDC 캐소드는 감소된 표면적을 가지는 비교적 조밀한 미세 구조를 나타내는 울퉁불퉁한 입자로 이루어지기 때문에 명확한 차이가 관찰될 수 있었다.For the formation of the nanofiber La x Sr 1 - x CoO 3 cathode, the SEM image of the GDC scaffold was confirmed after final heat treatment at 900 ° C, as shown in FIG. 4A. It was found that the deposition was in the form of a dendrites of nanofibers. This unique shape of the La x Sr 1 - x CoO 3 cathode provided an extended surface area due to the large triple phase boundary and allowed the flow of oxidant through the nanofiber structure. Conventional LSC / GDC cathodes were also produced by screen printing and sintering processes. The SEM image of the conventional LSC / GDC cathode is as shown in FIG. 4B. A clear difference could be observed because conventional LSC / GDC cathodes consist of rugged particles that exhibit a relatively dense microstructure with reduced surface area.
<실험예 2> 화학적 및 상 분석<Experiment 2> Chemical and phase analysis
La0 . 6CoO3의 화학 조성을 에너지 분산형 X선 분광법(EDS QUANTAX200, BRUKER)을 사용하여 관찰하였다. LaxSr1 - xCoO3 상 형성을 확인하기 위해 X-선 회절 분석을 수행 하였다(XRD, 2500 D / MAX, Rigaku). La 0 . 6 The chemical composition of CoO 3 was observed using energy dispersive X-ray spectroscopy (EDS QUANTAX200, BRUKER). X-ray diffraction analysis was performed to confirm the formation of La x Sr 1 - x CoO 3 phase (XRD, 2500 D / MAX, Rigaku).
La0 . 6CoO3에 대한 화학 양론적 증착을 얻기 위해, 수계 전해질의 다양한 조성을 사용하였다. EDS 분석은 750℃에서 열처리 단계 후에 La와 Co 증착물의 화학 양론을 찾기 위해 수행하였다. La 0 . To obtain stoichiometric deposition of 6 CoO 3 , various compositions of aqueous electrolytes were used. EDS analysis was performed to find the stoichiometry of the La and Co deposits after the heat treatment step at 750 ° C.
도 5에 나타난 바와 같이, 수계 전해질 LC1, LC2, LC3, LC4 및 LC로부터 증착된 La와 Co의 상세한 조성 분석은 하기 표 2에 나타난 바와 같다(도 5). La0 . 6CoO3에 대한 거의 이상적인 조성은 3.8 mM의 La3 + 농도를 함유하는 수계 전해질 LC5에 대해 관찰되었다. 3.8 mM의 La3 + 농도를 함유하는 수계 전해질이 스트론튬 침윤에 대한 샘플의 제조에 적절하였다.As shown in Fig. 5, detailed compositional analysis of La and Co deposited from the aqueous electrolytes LC1, LC2, LC3, LC4 and LC is shown in Table 2 below (Fig. 5). La 0 . 6 nearly ideal composition for a CoO 3 was observed for the water-based electrolyte LC5 containing La 3 + concentration of 3.8 mM. Aqueous electrolyte containing La 3 + concentration of 3.8 mM were suitable for preparation of samples for the strontium infiltration.
La0 . 6CoO3의 최적화된 화학 양론을 위한 La 및 Co 증착 후의 GDC 스캐폴드의 EDS 분석La 0 . 6 EDS analysis of GDC scaffold after La and Co deposition for optimized stoichiometry of CoO 3
샘플명Sample name
LC1LC1 LC2LC2 LC3LC3 LC4LC4 LC5LC5
성분ingredient O KO K 68.8168.81 66.9266.92 65.2565.25 59.0059.00 65.4965.49
Co KCo K 13.6313.63 14.2814.28 13.0713.07 10.7910.79 11.9011.90
La LLa L 2.002.00 4.434.43 4.734.73 4.724.72 5.955.95
Ce LCe L 14.1714.17 13.2213.22 15.5115.51 23.4623.46 15.1815.18
Gd LGd L 1.391.39 1.151.15 1.441.44 2.032.03 1.491.49
도 6에 나타난 바와 같이, 900℃에서 열처리 단계 후 최종적으로 제조된 나노 섬유성 LaxSr1 - xCoO3/GDC 복합 캐소드의 XRD 분석을 확인하였다(도 6). XRD 플롯은 스캐폴드 재료로서 존재하는 GDC의 고강도 피크를 나타낸다. 또한, ScCeSZ 피크는 캐소드 층의 두께가 작기 때문에 ScCeSZ 전해질에 대한 배경 간섭(background interference)으로 검출된다. LaxSr1 - xCoO3 캐소드의 피크는 화학적으로 보조된 증착 및 침윤 기술에 의해 제조된 원하는 페로브스카이트 캐소드의 형성을 나타내는 것으로 검출되었다. 소량의 코발트 산화물도 불순물로서 검출되었다. 또한, 캐소드에서의 산화 코발트의 존재는 SOFC의 전기 화학적 성능에 유익한 효과를 가져올 수 있다.As shown in FIG. 6, XRD analysis of the nanofibrous La x Sr 1 - x CoO 3 / GDC composite cathode finally produced after the heat treatment step at 900 ° C. was confirmed (FIG. 6). The XRD plot shows the high intensity peak of GDC present as a scaffold material. In addition, the ScCeSZ peak is detected as background interference to the ScCeSZ electrolyte because the thickness of the cathode layer is small. The peak of the La x Sr 1 - x CoO 3 cathode was detected to indicate the formation of the desired perovskite cathode prepared by chemically assisted deposition and infiltration techniques. A small amount of cobalt oxide was also detected as an impurity. In addition, the presence of cobalt oxide in the cathode can have a beneficial effect on the electrochemical performance of SOFC.
<실험예 3> 전기화학적 성능 분석 <Experiment 3> electrochemical performance analysis
SOFC의 전기 화학적 성능을 측정하기 위해, Ag 메쉬 (집 전자)를 각각 LSC 및 Ni 페이스트를 사용하여 캐소드 및 애노드에 부착시켰다. 전기 화학적 성능은 가습된 수소와 공기를 각각 연료와 산화제로 사용하여 700, 750 및 800℃에서 전류-전압-출력(IVP) 및 임피던스 데이터를 측정하여 기록하였다. DC 부하 장치를 사용하여 I-V 데이터를 획득하였다. 임피던스 데이터는 개방 회로 전압 조건 하에서 14 mV의 진폭으로 1 MHz 내지 100 mHz의 주파수 범위에서 BioLogic(SP240) 장치를 사용하여 기록하였다.To measure the electrochemical performance of SOFC, an Ag mesh (collector) was attached to the cathode and anode using LSC and Ni pastes, respectively. Electrochemical performance was recorded by measuring current-voltage-output (IVP) and impedance data at 700, 750 and 800 ° C using humidified hydrogen and air as fuel and oxidizer, respectively. I-V data was acquired using a DC load device. Impedance data was recorded using a BioLogic (SP240) device in the frequency range of 1 MHz to 100 mHz with an amplitude of 14 mV under open circuit voltage conditions.
도 7에 나타난 바와 같이, 다양한 작동 온도(700, 750 및 800℃)에서 나노 섬유 LaxSr1 - xCoO3/GDC 복합 캐소드 및 기존 LSC/GDC 복합 캐소드를 사용한 애노드 지지 버튼 셀에 대한 전기화학적 성능을 측정하였다. 모든 SOFC는 완벽한 전해질 층과 기밀 봉합을 통해 높은 OCV(> 1.1V) 값을 나타내었다. 나노섬유 LaxSr1 -xCoO3/GDC 복합 캐소드를 갖는 SOFC는 700, 750 및 800℃에서 각각 351, 613 및 950mW cm-2의 높은 출력 밀도를 보였다. 반면, 기존의 LSC/GDC 복합 캐소드를 갖는 SOFC는 700, 750 및 800℃에서 각각 82, 145 및 245 mW cm-2의 낮은 출력 밀도를 보였다. 화학적으로 보조된 증착 및 침윤 기술에 의해 제조된 나노 섬유 LaxSr1 -xCoO3/GDC 복합 캐소드를 갖는 SOFC는 700℃의 작동 온도에서 종래의 LSC/GDC 복합 캐소드를 갖는 SOFC 보다 4.28배 더 큰 성능을 나타내었다. 증가된 성능은 새로운 캐소드의 나노섬유 미세 구조 및 낮은 제조 온도에 기인한 것임을 확인하였다.As shown in FIG. 7, electrochemical for anode support button cells using nanofiber La x Sr 1 - x CoO 3 / GDC composite cathodes and conventional LSC / GDC composite cathodes at various operating temperatures (700, 750 and 800 ° C.) Performance was measured. All SOFCs exhibited high OCV (> 1.1 V) values through a complete electrolyte layer and hermetic sealing. SOFCs with nanofiber La x Sr 1 -x CoO 3 / GDC composite cathodes exhibited high power densities of 351, 613 and 950 mW cm -2 at 700, 750 and 800 ° C, respectively. On the other hand, SOFCs having a conventional LSC / GDC composite cathode exhibited low power densities of 82, 145 and 245 mW cm -2 at 700, 750 and 800 ° C, respectively. SOFCs with nanofiber La x Sr 1 -x CoO 3 / GDC composite cathodes prepared by chemically assisted deposition and infiltration techniques are 4.28 times more than SOFCs with conventional LSC / GDC composite cathodes at operating temperatures of 700 ° C. It showed great performance. It was confirmed that the increased performance was due to the nanofiber microstructure of the new cathode and low manufacturing temperature.
전기화학적 임피던스 데이터는 도 8에 나타난 바와 같이, 다양한 작동 온도에서 나노섬유 LaxSr1 - xCoO3/GDC 복합 캐소드 및 기존 LSC/GDC 복합 캐소드를 갖는 SOFC에 대한 개방 회로 전압 조건 하에서 측정하였다. 도 8에 나타난 바와 같이, 나노섬유 LaxSr1 - xCoO3/GDC 복합 캐소드를 갖는 SOFC는 종래의 LSC/GDC 복합 캐소드를 갖는 SOFC와 비교하여 더 작은 오믹 및 분극 저항을 나타내는 우수한 성능을 나타내었다. 나노섬유 LaxSr1 - xCoO3/GDC 복합 캐소드 및 기존 LSC/GDC 복합 캐소드를 이용한 SOFC에 대해 측정된 다양한 전기 화학 성능 매개 변수는 하기 표 3에 나열된 바와 같다.Electrochemical impedance data was measured under open circuit voltage conditions for SOFCs with nanofiber La x Sr 1 - x CoO 3 / GDC composite cathodes and conventional LSC / GDC composite cathodes at various operating temperatures, as shown in FIG. 8. As shown in FIG. 8, the SOFC with the nanofiber La x Sr 1 - x CoO 3 / GDC composite cathode exhibits excellent performance showing smaller ohmic and polarization resistance compared to the SOFC with the conventional LSC / GDC composite cathode. Did. Various electrochemical performance parameters measured for SOFC using nanofiber La x Sr 1 - x CoO 3 / GDC composite cathode and conventional LSC / GDC composite cathode are listed in Table 3 below.
나노섬유 LaxSr1 - xCoO3/GDC 복합 캐소드 및 기존 LSC/GDC 복합 캐소드를 갖는 SOFC의 전기 화학적 성능Electrochemical performance of SOFC with nanofiber La x Sr 1 - x CoO 3 / GDC composite cathode and conventional LSC / GDC composite cathode
제조방법/개방온도(℃)Manufacturing method / opening temperature (℃) 재래식 소결(Conventional sintering)Conventional sintering 전착(Electrodeposition)Electrodeposition
Pmax(mW cm-2)P max (mW cm -2 ) Rohmic(Ωcm2)R ohmic (Ωcm 2 ) Rpolarization(Ωcm2)R polarization (Ωcm 2 ) Pmax(mW cm-2)P max (mW cm -2 ) Rohmic(Ωcm2)R ohmic (Ωcm 2 ) Rpolarization(Ωcm2)R polarization (Ωcm 2 )
700700 8282 0.400.40 7.437.43 351351 0.190.19 1.311.31
750750 145145 0.360.36 5.185.18 613613 0.170.17 0.770.77
800800 246246 0.310.31 2.442.44 950950 0.1650.165 0.470.47

Claims (9)

  1. 다공성 이온전도 스캐폴드(scaffold)의 표면에 탄소나노튜브를 형성하는 단계; Forming a carbon nanotube on the surface of the porous ion conducting scaffold;
    상기 탄소나노튜브 상에 란타넘-코발트(La-Co) 산화물을 전착(electrodeposition)시키는 단계;Electrodeposition of a lanthanum-cobalt (La-Co) oxide on the carbon nanotubes;
    상기 스캐폴드를 열처리하여 탄소나노튜브를 제거하는 단계;Heat-treating the scaffold to remove carbon nanotubes;
    상기 스캐폴드에 스트론튬(Sr)을 침윤(infiltration)시키는 단계; 및Infiltration of strontium (Sr) into the scaffold; And
    상기 스캐폴드를 열처리하여 나노섬유의 란타넘-스트론튬-코발트(La-Sr-Co) 산화물을 형성하는 단계;Heat-treating the scaffold to form a lanthanum-strontium-cobalt (La-Sr-Co) oxide of nanofibers;
    를 포함하는 고체산화물 연료전지 공기극의 제조방법.Method of manufacturing a cathode of a solid oxide fuel cell comprising a.
  2. 제1항에 있어서,According to claim 1,
    상기 다공성 이온전도 스캐폴드는,The porous ion conducting scaffold,
    GDC(Gd-doped ceria) 분말, 용매, 결합제 및 기공형성제를 혼합한 GDC 잉크를 제조하는 단계; 및Preparing a GDC ink in which Gd-doped ceria (GDC) powder, a solvent, a binder, and a pore-forming agent are mixed; And
    상기 GDC 잉크를 ScCeSZ 전해질 층 위에 스크린 인쇄한 후 열처리하는 단계;Heat-treating the GDC ink after screen printing on the ScCeSZ electrolyte layer;
    를 포함하는 방법으로 제조되는 것을 특징으로 하는 고체산화물 연료전지 공기극의 제조방법.Method for producing a solid oxide fuel cell cathode, characterized in that it is produced by a method comprising a.
  3. 제1항에 있어서,According to claim 1,
    상기 탄소나노튜브는The carbon nanotube
    전이금속 나노 입자를 상기 스캐폴드에 침투 분산시키는 단계; 및Permeating and dispersing transition metal nanoparticles into the scaffold; And
    탄소 소스를 공급하여 상기 전이금속 나노 입자로부터 탄소나노튜브를 성장시키는 단계;Growing a carbon nanotube from the transition metal nanoparticles by supplying a carbon source;
    를 포함하는 방법으로 형성되는 것을 특징으로 하는 고체산화물 연료전지 공기극의 제조방법.A method of manufacturing a cathode of a solid oxide fuel cell, characterized in that it is formed by a method comprising a.
  4. 제1항에 있어서,According to claim 1,
    상기 스트론튬의 침윤은The infiltration of strontium is
    질산 스트론튬 분말을 용매에 첨가하여 용해시켜 질산 스트론튬 용액을 제조하는 단계; 및Preparing a solution of strontium nitrate by dissolving strontium nitrate powder by adding it to a solvent; And
    상기 질산 스트론튬 용액을 란타넘-코발트 산화물로 증착된 스캐폴드에 첨가하여 침윤시킨 후 건조시키는 단계;Adding the strontium nitrate solution to a scaffold deposited with lanthanum-cobalt oxide to infiltrate and drying;
    를 포함하는 방법으로 수행되는 것을 특징으로 하는 고체산화물 연료전지 공기극의 제조방법.Method of manufacturing a solid oxide fuel cell cathode, characterized in that it is carried out by a method comprising a.
  5. 다공성 이온전도 스캐폴드; 및Porous ion conducting scaffolds; And
    상기 다공성 이온전도 스캐폴드에 형성된 나노섬유 형태의 LaxSr1 - xCoO3 (여기서, X는 0 < X < 1의 소수);을 포함하는,La x Sr 1 - x CoO 3 in the form of nanofibers formed on the porous ion conducting scaffold (where X is a prime number of 0 <X <1);
    고체산화물 연료전지 공기극.Solid oxide fuel cell cathode.
  6. 제5항에 있어서,The method of claim 5,
    상기 다공성 이온전도 스캐폴드는 다공성 GDC(Gd-doped ceria) 스캐폴드인 것을 특징으로 하는 고체산화물 연료전지 공기극.The porous ion conductive scaffold is a porous GDC (Gd-doped ceria) scaffold, characterized in that the solid oxide fuel cell cathode.
  7. 제5항의 공기극;The cathode of claim 5;
    연료극; 및Anode; And
    상기 공기극과 상기 연료극 사이에 구비된 전해질층Electrolyte layer provided between the cathode and the anode
    을 포함하는 고체산화물 연료전지.Solid oxide fuel cell comprising a.
  8. 제7항에 있어서,The method of claim 7,
    상기 연료극은 NiO-ScCeSZ 또는 NiO-YSZ으로 형성되는 것을 특징으로 하는 고체산화물 연료전지.The anode is a solid oxide fuel cell, characterized in that formed of NiO-ScCeSZ or NiO-YSZ.
  9. 제7항에 있어서,The method of claim 7,
    상기 전해질층은 이트륨 안정화 지르코니아, 스칸디움 안정화 지르코니아 및 가돌리움 도핑된 세리아 중 적어도 하나로 형성되는 것을 특징으로 하는 고체산화물 연료전지.The electrolyte layer is a solid oxide fuel cell characterized in that it is formed of at least one of yttrium stabilized zirconia, scandium stabilized zirconia and gadolium doped ceria.
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