US20060171839A1 - Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni-Al alloy and method for making the same - Google Patents

Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni-Al alloy and method for making the same Download PDF

Info

Publication number
US20060171839A1
US20060171839A1 US11/208,903 US20890305A US2006171839A1 US 20060171839 A1 US20060171839 A1 US 20060171839A1 US 20890305 A US20890305 A US 20890305A US 2006171839 A1 US2006171839 A1 US 2006171839A1
Authority
US
United States
Prior art keywords
alloy
sheet
nickel
fuel cell
sintering
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US11/208,903
Inventor
Sung Yoon
Seong Hong
In Oh
Tae Lim
Suk-Woo Nam
Heung Ha
Jonghee Han
Eun Cho
Jaeyoung Lee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Korea Advanced Institute of Science and Technology KAIST
Original Assignee
Korea Advanced Institute of Science and Technology KAIST
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Korea Advanced Institute of Science and Technology KAIST filed Critical Korea Advanced Institute of Science and Technology KAIST
Assigned to KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY reassignment KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CHO, EUN AE, HA, HEUNG YONG, HAN, JONGHEE, HONG, SEONG AHN, LEE, JAEYOUNG, LIM, TAE HOON, NAM, SUK-WOO, OH, IN HWAN, YOON, SUNG PIL
Publication of US20060171839A1 publication Critical patent/US20060171839A1/en
Priority to US12/476,779 priority Critical patent/US8415075B2/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
    • F21S2/005—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction of modular construction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V23/00—Arrangement of electric circuit elements in or on lighting devices
    • F21V23/003—Arrangement of electric circuit elements in or on lighting devices the elements being electronics drivers or controllers for operating the light source, e.g. for a LED array
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/50—Cooling arrangements
    • F21V29/70—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks
    • F21V29/74—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks with fins or blades
    • 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
    • H01M4/8605—Porous electrodes
    • 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
    • H01M4/8875—Methods for shaping the electrode into free-standing bodies, like sheets, films or grids, e.g. moulding, hot-pressing, casting without support, extrusion without support
    • 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
    • H01M4/8878—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
    • H01M4/8885—Sintering or firing
    • 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
    • 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
    • H01M8/14—Fuel cells with fused electrolytes
    • H01M8/141—Fuel cells with fused electrolytes the anode and the cathode being gas-permeable electrodes or electrode layers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]
    • 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 Ni—Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni—Al alloy and a method for making the Ni—Al alloy anode.
  • a fuel cell is used for directly converting chemical energy into electric energy.
  • the fuel cell such as a molten carbonate fuel cell, a solid polymer electrolyte fuel cell, and a solid oxide fuel cell etc.
  • the molten carbonate fuel cell is a fuel cell using the molten carbonate as its electrolyte and comprises a cathode, an electrolyte, a support and an anode etc.
  • a high temperature fuel cell operating at 500° C. or more such as the molten carbonate fuel cell and the solid oxide fuel cell, mainly uses nickel for an electrode.
  • the molten carbonate fuel cell uses nickel for an anode and nickel oxide (NiO) for a cathode.
  • the anode in which an oxidation reaction of fuel occurs has serious problems of sintering and creep phenomena at an operating condition of high temperature and high load of 2 kg/cm 2 or more. That is, the reduction of porosity and the change of micro-structure such as a shrinkage etc. occur in the anode due to the sintering and the creep phenomena, thereby causing a degradation of the performance of the fuel cell.
  • the nickel electrode is manufactured to be porous so as to enlarge a reaction area and to provide a gas passage.
  • a porous nickel electrode is used at a high temperature for a long time, the surface area and reaction rate of the nickel electrode are reduced due to the sintering.
  • a fuel cell having stacks of several unit cells using the porous nickel electrode is operated for a long time, there occurs a creep in the porous nickel electrode due to the load of the fuel cell, thereby reducing the performance of the fuel cell.
  • a chromium of about 10 wt % was added to the nickel or an oxide such as Cr 2 O 3 and LiCrO 2 was formed on the surface of the nickel electrode in order to improve the resistance of the nickel electrode to the sintering and the creep. It is known that a creep strain of Ni+10% Cr anode is 5% or less. However, the LiCrO 2 formed on the surface of the nickel electrode is dissolved in the electrolyte, thereby deteriorating the resistance of the nickel electrode to the sintering and the creep when the fuel cell is operated for a long time.
  • ODS oxide dispersion strengthened
  • the prior Ni—Al alloy electrode is expensive compared to the electrode using the existing material and has such a problem that the Ni—Al alloy electrode is not sintered in a general manufacturing process of the electrode. That is, the aluminum formed as a solid solution is primarily oxidized on the surface of the nickel electrode, thereby forming an alumina oxide having a very high melting point on the surface. Due to the alumina oxide, the sintering between the nickel particles becomes difficult.
  • the partial oxidation-reduction method uses a phenomenon that when the nickel is oxidized into a nickel oxide, the density is changed and a volume is thus expanded. According to the partial oxidation-reduction method, the nickel particles can easily contact with each other due to the surface oxidation of the nickel, so that it is possible to progress a sintering process despite the formation of the alumina oxide and to manufacture an electrode having a proper strength. In the partial oxidation-reduction method, it is very important to control a partial pressure of oxygen, thereby preventing an occurrence of excessive micro-pores due to the volume change between nickel and nickel oxide resulting from the excessive oxidation of the nickel particle. The micro-pores eventually cause a re-distribution of the electrolyte, thereby exerting very bad influence on the life of the fuel cell.
  • the object of the present invention is to provide a Ni—Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni—Al alloy and a method for making the same, wherein a reaction activity of the Ni—Al alloy anode can be maintained, the method is simple and economic, and a mass production of the Ni—Al alloy anode and a scale-up in the method are easy.
  • a Ni—Al alloy anode for molten carbonate fuel cell wherein a sheet made of Ni—Al alloy powders is directly installed in the cell without any heat treatment for sintering the Ni—Al alloy in the sheet and then the Ni—Al alloy in the sheet is in-situ sintered during a pretreatment process of the cell with the sheet.
  • an inert gas is injected so as to control an oxidation of nickel during the in-situ sintering process.
  • the inert gas is injected up to the point before a temperature at which organic binders used to prepare the sheet are removed, then air is injected in such a temperature scope wherein the organic binders are removed, and then hydrogen and carbon dioxide are simultaneously injected after the removal of the organic binders and up to the point before an operating temperature of the cell.
  • a method for preparing a Ni—Al alloy anode for molten carbonate fuel cell comprising steps of preparing a sheet with Ni—Al alloy powders (S 1 ); and installing the sheet in a fuel cell without any heat treatment for sintering the Ni—Al alloy in the sheet and then in-situ sintering the Ni—Al alloy in the sheet during a pretreatment process of the cell with the sheet (S 2 ).
  • an inert gas is injected so as to control an oxidation of nickel during the in-situ sintering process.
  • the inert gas is injected up to the point before a temperature at which organic binders used to prepare the sheet are removed, then air is injected in such a temperature scope wherein the organic binders are removed, and then hydrogen and carbon dioxide are simultaneously injected after the removal of the organic binders and up to the point before an operating temperature of the cell.
  • FIG. 1 is a graph showing heat treatment conditions and atmospheres when a tape made of nickel-aluminum alloy powders is directly installed in a cell without any separate heat treatment for sintering the nickel-aluminum alloy in the tape and then a nickel-aluminum alloy anode is prepared with in-situ sintering the nickel-aluminum alloy in the tape according to the present invention.;
  • FIG. 2 is a graph showing a long time performance of a unit cell using a nickel-aluminum alloy anode for molten carbonate fuel cell made by in-situ sintering the nickel-aluminum alloy according to the present invention.
  • a pretreatment process of cell is a pretreatment process of cell having a sheet made of nickel-aluminum alloy powders installed therein directly without any heat treatment for sintering the nickel-aluminum alloy in the sheet, and means a process of removing an organic material such as a binder and a plasticizer, etc. used to prepare the sheet or a process comprising the removing of the organic material and a heating up to the point before an operating temperature of the cell.
  • a sheet is prepared by, for example, the tape-casting of nickel-aluminum alloy powders, which are difficult to be sintered as mentioned above (S 1 ). Subsequently, the sheet is directly installed to a cell without any heat treatment for sintering the nickel-aluminum alloy in the sheet, and then the nickel-aluminum alloy in the sheet is in-situ sintered in a process of removing an organic material such as a binder or a plasticizer added for preparing the sheet, or in a process of heating up to the point before an operating temperature of the cell after removing the organic material (S 2 ).
  • an organic material such as a binder or a plasticizer added for preparing the sheet
  • the method for preparing the nickel-aluminum alloy anode according to the present invention is simple and economic, and a scale-up in the method and a mass production of the nickel-aluminum alloy anode are easy while a reaction activity of the nickel-aluminum alloy anode is maintained.
  • an oxidation control is performed by injecting an inert gas such as nitrogen or argon in a specific temperature range so as to prevent an excessive oxidation of the nickel. Further, at this time, a temperature at which the inert gas is injected is determined by a temperature at which the organic materials such as an organic binder and plasticizer, etc. added in the tape-casting process are removed by a thermal decomposition and an oxidation, etc.
  • the organic binder added in the tape-casting process is mostly removed at 300° C. ⁇ 400° C. If the pretreatment is performed with the inert gas such as nitrogen or argon in the temperature range for a long time, there can occur carbon deposits, which may exert a bad influence on a cell performance.
  • the inert gas such as nitrogen or argon
  • a plasticizer which has a low volatilization temperature, among the organic materials added in the tape-casting process should be primarily volatilized in the temperature range (200° C. ⁇ 300° C.), and then the pretreatment should be performed with air or oxygen instead of nitrogen etc. in the temperature range (300° C. ⁇ 400° C.) at which the organic binders are removed. Further, the air or oxygen treatment should be performed only for a minimal time for which the organic binder is completely removed.
  • the method when preparing a nickel-aluminum alloy anode for a molten carbonate fuel cell, it is possible to simplify the preparing process of the anode since an additional heat treatment process is not necessary.
  • the method is economic, and the scale-up in the method and the mass production of the nickel-aluminum alloy anode are easy while a reaction activity of the nickel-aluminum alloy anode is maintained.
  • a tape of nickel-aluminum alloy powders (i.e., a green sheet) was prepared as follows:
  • a binder, a solvent, a plasticizer and a defoamer were primary-mixed and ball-milled for 24 hours, and then nickel-aluminum alloy powders (5 wt % or less aluminum) and a disperant were secondary-mixed and ball-milled for 2 ⁇ 48 hours, thereby making a slurry.
  • Methyl cellulose 1500 (Hayashi Pure Chemical) was used as the binder. Water was used as the solvent. Glycerol (Junsei Chemical) was used as the plasticizer. SN 154 (San Nopco Korea) and Cerasperse 5468 (San Nopco Korea) were used as the defoamer and the disperant, respectively.
  • a porosity property of the anode could be regulated to a level required for a molten carbonate fuel cell. Pores in the slurry, which were generated when performing the ball-mill, were removed through a defoaming process, and a viscosity was regulated to about 10,000 ⁇ 15,000 cP so as to maintain a thickness of the green sheet uniformly.
  • a green sheet slip was prepared with a tape-casting process using a doctor blade, and a drying was performed at a room temperature. After preparing and drying the green sheet, a green sheet cut to a size of 10 cm ⁇ 10 cm was directly installed to a unit cell. Then, an in-situ sintering was performed in the pretreatment process of the unit cell.
  • FIG. 1 is a graph showing heat treatment conditions and atmospheres when a tape made of nickel-aluminum alloy powders is directly installed in a cell without any separate heat treatment for sintering the nickel-aluminum alloy in the tape and then a nickel-aluminum alloy anode is prepared with in-situ sintering the nickel-aluminum alloy in the tape according to the present invention
  • an inert gas such as nitrogen (or argon) was injected from a room temperature to 250° C. (for 96 hours) during a heating process comprising a process for removing the binder and the plasticizer, etc. of the tape so as to remove the plasticizer having a low volatilization temperature and to prevent an excessive oxidation of nickel in the nickel-aluminum alloy.
  • air was blown in the temperature range of 250° C. ⁇ 450° C. (for 24 hours) so as to completely remove the organic binder.
  • hydrogen and carbon dioxide were simultaneously injected in the temperature range of 450° C. ⁇ 650° C. (for 24 hours) so as to prevent an excessive nickel oxidation of the nickel-aluminum particles.
  • FIG. 2 is a graph showing a long time performance of a unit cell using a nickel-aluminum alloy anode for molten carbonate fuel cell made by in-situ sintering the nickel-aluminum alloy according to the present invention.
  • the unit cell using a nickel-aluminum alloy anode for molten carbonate fuel cell made by in-situ sintering the nickel-aluminum alloy according to the present invention exhibits a constant performance for 1,000 hours.
  • the cell exhibits an electrical conductivity and a nitrogen cross-over, etc., which are equal or superior to those of an anode made by an ex-situ sintering method such as the existing partial oxidation-reduction method.

Abstract

Disclosed is a Ni—Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni—Al alloy. Further, disclosed is a method for preparing the same comprising steps of preparing a sheet with Ni—Al alloy powders (S1); and installing the sheet in a fuel cell without any heat treatment for sintering the Ni—Al alloy in the sheet and then in-situ sintering the Ni—Al alloy in the sheet during a pretreatment process of the cell with the sheet (S2), wherein a reaction activity of the Ni—Al alloy anode can be maintained, the method is simple and economic, and a mass production of the Ni—Al alloy anode and a scale-up in the method are easy.

Description

    BACKGROUND OF THE INVENTION
  • 1. Field of the Invention
  • The present invention relates to a Ni—Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni—Al alloy and a method for making the Ni—Al alloy anode.
  • 2. Description of the Related Art
  • A fuel cell is used for directly converting chemical energy into electric energy. There are various kinds of the fuel cell, such as a molten carbonate fuel cell, a solid polymer electrolyte fuel cell, and a solid oxide fuel cell etc. The molten carbonate fuel cell is a fuel cell using the molten carbonate as its electrolyte and comprises a cathode, an electrolyte, a support and an anode etc.
  • A high temperature fuel cell operating at 500° C. or more, such as the molten carbonate fuel cell and the solid oxide fuel cell, mainly uses nickel for an electrode. For example, the molten carbonate fuel cell uses nickel for an anode and nickel oxide (NiO) for a cathode.
  • The anode in which an oxidation reaction of fuel occurs has serious problems of sintering and creep phenomena at an operating condition of high temperature and high load of 2 kg/cm2 or more. That is, the reduction of porosity and the change of micro-structure such as a shrinkage etc. occur in the anode due to the sintering and the creep phenomena, thereby causing a degradation of the performance of the fuel cell.
  • In particular, the nickel electrode is manufactured to be porous so as to enlarge a reaction area and to provide a gas passage. When such a porous nickel electrode is used at a high temperature for a long time, the surface area and reaction rate of the nickel electrode are reduced due to the sintering. In addition, when a fuel cell having stacks of several unit cells using the porous nickel electrode is operated for a long time, there occurs a creep in the porous nickel electrode due to the load of the fuel cell, thereby reducing the performance of the fuel cell.
  • In the prior art for solving the above-mentioned problems of the sintering and the creep, a chromium of about 10 wt % was added to the nickel or an oxide such as Cr2O3 and LiCrO2 was formed on the surface of the nickel electrode in order to improve the resistance of the nickel electrode to the sintering and the creep. It is known that a creep strain of Ni+10% Cr anode is 5% or less. However, the LiCrO2 formed on the surface of the nickel electrode is dissolved in the electrolyte, thereby deteriorating the resistance of the nickel electrode to the sintering and the creep when the fuel cell is operated for a long time.
  • In order to improve the creep characteristic, there has been used an oxide dispersion strengthened (ODS) method of dispersing a metal oxide such as alumina in the nickel electrode since the mid-1980's. Further, there have been extensive studies for an electrode consisting of Ni—Al based alloy containing a small amount of aluminum, which is oxidized prior to nickel. It is known that the electrode consisting of Ni—Al based alloy has a creep strain of 0.5% or less and an increase of contact resistance is very slight even in a size of 1 m2, which is a size of a commercial electrode.
  • However, the prior Ni—Al alloy electrode is expensive compared to the electrode using the existing material and has such a problem that the Ni—Al alloy electrode is not sintered in a general manufacturing process of the electrode. That is, the aluminum formed as a solid solution is primarily oxidized on the surface of the nickel electrode, thereby forming an alumina oxide having a very high melting point on the surface. Due to the alumina oxide, the sintering between the nickel particles becomes difficult.
  • Under the circumstances, there has been used a method of sintering the electrode through a partial oxidation-reduction wherein the surface of the electrode is partially oxidized under the condition that the nickel particle can be oxidized, and then the surface of the electrode is reduced again.
  • The partial oxidation-reduction method uses a phenomenon that when the nickel is oxidized into a nickel oxide, the density is changed and a volume is thus expanded. According to the partial oxidation-reduction method, the nickel particles can easily contact with each other due to the surface oxidation of the nickel, so that it is possible to progress a sintering process despite the formation of the alumina oxide and to manufacture an electrode having a proper strength. In the partial oxidation-reduction method, it is very important to control a partial pressure of oxygen, thereby preventing an occurrence of excessive micro-pores due to the volume change between nickel and nickel oxide resulting from the excessive oxidation of the nickel particle. The micro-pores eventually cause a re-distribution of the electrolyte, thereby exerting very bad influence on the life of the fuel cell.
  • As mentioned above, since the partial pressure of oxygen should be controlled, there have been such problems in the partial oxidation-reduction method that it is very difficult to introduce a continuous process required for a mass production and that necessary equipments become very complicated.
    • SUMMARY OF THE INVENTION
  • Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art. The object of the present invention is to provide a Ni—Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni—Al alloy and a method for making the same, wherein a reaction activity of the Ni—Al alloy anode can be maintained, the method is simple and economic, and a mass production of the Ni—Al alloy anode and a scale-up in the method are easy.
  • In order to accomplish the object, there is provided a Ni—Al alloy anode for molten carbonate fuel cell wherein a sheet made of Ni—Al alloy powders is directly installed in the cell without any heat treatment for sintering the Ni—Al alloy in the sheet and then the Ni—Al alloy in the sheet is in-situ sintered during a pretreatment process of the cell with the sheet.
  • In the Ni—Al alloy anode for molten carbonate fuel cell according to the present invention, an inert gas is injected so as to control an oxidation of nickel during the in-situ sintering process.
  • In the Ni—Al alloy anode for molten carbonate fuel cell according to the present invention, during the in-situ sintering process, the inert gas is injected up to the point before a temperature at which organic binders used to prepare the sheet are removed, then air is injected in such a temperature scope wherein the organic binders are removed, and then hydrogen and carbon dioxide are simultaneously injected after the removal of the organic binders and up to the point before an operating temperature of the cell.
  • In order to accomplish the object, there is provided a method for preparing a Ni—Al alloy anode for molten carbonate fuel cell comprising steps of preparing a sheet with Ni—Al alloy powders (S1); and installing the sheet in a fuel cell without any heat treatment for sintering the Ni—Al alloy in the sheet and then in-situ sintering the Ni—Al alloy in the sheet during a pretreatment process of the cell with the sheet (S2).
  • In the step of S2, an inert gas is injected so as to control an oxidation of nickel during the in-situ sintering process.
  • In the step of S2, during the in-situ sintering process, the inert gas is injected up to the point before a temperature at which organic binders used to prepare the sheet are removed, then air is injected in such a temperature scope wherein the organic binders are removed, and then hydrogen and carbon dioxide are simultaneously injected after the removal of the organic binders and up to the point before an operating temperature of the cell.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a graph showing heat treatment conditions and atmospheres when a tape made of nickel-aluminum alloy powders is directly installed in a cell without any separate heat treatment for sintering the nickel-aluminum alloy in the tape and then a nickel-aluminum alloy anode is prepared with in-situ sintering the nickel-aluminum alloy in the tape according to the present invention.; and
  • FIG. 2 is a graph showing a long time performance of a unit cell using a nickel-aluminum alloy anode for molten carbonate fuel cell made by in-situ sintering the nickel-aluminum alloy according to the present invention.
    • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • Hereinafter, the present invention will be described in detail by describing preferred embodiments with reference to the accompanying drawings.
  • In the present invention, “a pretreatment process of cell” is a pretreatment process of cell having a sheet made of nickel-aluminum alloy powders installed therein directly without any heat treatment for sintering the nickel-aluminum alloy in the sheet, and means a process of removing an organic material such as a binder and a plasticizer, etc. used to prepare the sheet or a process comprising the removing of the organic material and a heating up to the point before an operating temperature of the cell.
  • According to the invention, a sheet is prepared by, for example, the tape-casting of nickel-aluminum alloy powders, which are difficult to be sintered as mentioned above (S1). Subsequently, the sheet is directly installed to a cell without any heat treatment for sintering the nickel-aluminum alloy in the sheet, and then the nickel-aluminum alloy in the sheet is in-situ sintered in a process of removing an organic material such as a binder or a plasticizer added for preparing the sheet, or in a process of heating up to the point before an operating temperature of the cell after removing the organic material (S2). Thereby, the method for preparing the nickel-aluminum alloy anode according to the present invention is simple and economic, and a scale-up in the method and a mass production of the nickel-aluminum alloy anode are easy while a reaction activity of the nickel-aluminum alloy anode is maintained.
  • In particular, during the in-situ sintering of the nickel-aluminum alloy, an oxidation control is performed by injecting an inert gas such as nitrogen or argon in a specific temperature range so as to prevent an excessive oxidation of the nickel. Further, at this time, a temperature at which the inert gas is injected is determined by a temperature at which the organic materials such as an organic binder and plasticizer, etc. added in the tape-casting process are removed by a thermal decomposition and an oxidation, etc.
  • That is, the organic binder added in the tape-casting process is mostly removed at 300° C.˜400° C. If the pretreatment is performed with the inert gas such as nitrogen or argon in the temperature range for a long time, there can occur carbon deposits, which may exert a bad influence on a cell performance.
  • Accordingly, a plasticizer, which has a low volatilization temperature, among the organic materials added in the tape-casting process should be primarily volatilized in the temperature range (200° C.˜300° C.), and then the pretreatment should be performed with air or oxygen instead of nitrogen etc. in the temperature range (300° C.˜400° C.) at which the organic binders are removed. Further, the air or oxygen treatment should be performed only for a minimal time for which the organic binder is completely removed.
  • According to the invention, when preparing a nickel-aluminum alloy anode for a molten carbonate fuel cell, it is possible to simplify the preparing process of the anode since an additional heat treatment process is not necessary. In addition, the method is economic, and the scale-up in the method and the mass production of the nickel-aluminum alloy anode are easy while a reaction activity of the nickel-aluminum alloy anode is maintained.
    • EXAMPLE
  • A tape of nickel-aluminum alloy powders (i.e., a green sheet) was prepared as follows:
  • At first, a binder, a solvent, a plasticizer and a defoamer were primary-mixed and ball-milled for 24 hours, and then nickel-aluminum alloy powders (5 wt % or less aluminum) and a disperant were secondary-mixed and ball-milled for 2˜48 hours, thereby making a slurry.
  • Methyl cellulose 1500 (Hayashi Pure Chemical) was used as the binder. Water was used as the solvent. Glycerol (Junsei Chemical) was used as the plasticizer. SN 154 (San Nopco Korea) and Cerasperse 5468 (San Nopco Korea) were used as the defoamer and the disperant, respectively.
  • Based on 100 g of the nickel-aluminum alloy powders, 1˜2 g of the binder, 40˜50 g of the solvent, 1˜2 g of the plasticizer, 0.1˜1 g of the defoamer and 0.1˜1 g of the disperant were respectively used.
  • It could be checked through a slurry deposition experiment that the materials added when performing the second ball-mill were uniformly mixed. By regulating the second ball-mill time, a porosity property of the anode could be regulated to a level required for a molten carbonate fuel cell. Pores in the slurry, which were generated when performing the ball-mill, were removed through a defoaming process, and a viscosity was regulated to about 10,000˜15,000 cP so as to maintain a thickness of the green sheet uniformly.
  • A green sheet slip was prepared with a tape-casting process using a doctor blade, and a drying was performed at a room temperature. After preparing and drying the green sheet, a green sheet cut to a size of 10 cm×10 cm was directly installed to a unit cell. Then, an in-situ sintering was performed in the pretreatment process of the unit cell.
  • FIG. 1 is a graph showing heat treatment conditions and atmospheres when a tape made of nickel-aluminum alloy powders is directly installed in a cell without any separate heat treatment for sintering the nickel-aluminum alloy in the tape and then a nickel-aluminum alloy anode is prepared with in-situ sintering the nickel-aluminum alloy in the tape according to the present invention
  • As shown in FIG. 1, an inert gas such as nitrogen (or argon) was injected from a room temperature to 250° C. (for 96 hours) during a heating process comprising a process for removing the binder and the plasticizer, etc. of the tape so as to remove the plasticizer having a low volatilization temperature and to prevent an excessive oxidation of nickel in the nickel-aluminum alloy. Then, air was blown in the temperature range of 250° C.˜450° C. (for 24 hours) so as to completely remove the organic binder. Then, hydrogen and carbon dioxide were simultaneously injected in the temperature range of 450° C.˜650° C. (for 24 hours) so as to prevent an excessive nickel oxidation of the nickel-aluminum particles.
  • FIG. 2 is a graph showing a long time performance of a unit cell using a nickel-aluminum alloy anode for molten carbonate fuel cell made by in-situ sintering the nickel-aluminum alloy according to the present invention.
  • As shown in FIG. 2, the unit cell using a nickel-aluminum alloy anode for molten carbonate fuel cell made by in-situ sintering the nickel-aluminum alloy according to the present invention exhibits a constant performance for 1,000 hours.
  • Further, the cell exhibits an electrical conductivity and a nitrogen cross-over, etc., which are equal or superior to those of an anode made by an ex-situ sintering method such as the existing partial oxidation-reduction method.
  • Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the invention. Therefore, it must be understood that the embodiment and example described above should not be taken as limiting the invention as defined by the following claims. The claims are thus to be understood to include what is specifically described above, what is conceptionally equivalent, what can be obviously substituted and also what essentially incorporates the essential idea of he invention.

Claims (6)

1. A Ni—Al alloy anode for molten carbonate fuel cell wherein a sheet made of Ni—Al alloy powders is directly installed in the cell without any heat treatment for sintering the Ni—Al alloy in the sheet and then the Ni—Al alloy in the sheet is in-situ sintered during a pretreatment process of the cell with the sheet.
2. The Ni—Al alloy anode according to claim 1, wherein an inert gas is injected so as to control an oxidation of nickel during the in-situ sintering process.
3. The Ni—Al alloy anode according to claim 1, wherein, during the in-situ sintering process, the inert gas is injected up to the point before a temperature at which organic binders used to prepare the sheet are removed, then air is injected in such a temperature scope wherein the organic binders are removed, and then hydrogen and carbon dioxide are simultaneously injected after the removal of the organic binders and up to the point before an operating temperature of the cell.
4. A method for preparing a Ni—Al alloy anode for molten carbonate fuel cell comprising steps of:
preparing a sheet with Ni—Al alloy powders (S1); and
installing the sheet in a fuel cell without any heat treatment for sintering the Ni—Al alloy in the sheet, and then in-situ sintering the Ni—Al alloy in the sheet during a pretreatment process of the cell with the sheet (S2).
5. The method according to claim 4, wherein, in the step of S2, an inert gas is injected so as to control an oxidation of nickel during the in-situ sintering process.
6. The method according to claim 5, wherein, In the step of S2, during the in-situ sintering process, the inert gas is injected up to the point before a temperature at which organic binders used to prepare the sheet are removed, then air is injected in such a temperature scope wherein the organic binders are removed, and then hydrogen and carbon dioxide are simultaneously injected after the removal of the organic binders and up to the point before an operating temperature of the cell.
US11/208,903 2005-02-01 2005-08-22 Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni-Al alloy and method for making the same Abandoned US20060171839A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/476,779 US8415075B2 (en) 2005-02-01 2009-06-02 Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR10-2005-0008954 2005-02-01
KR1020050008954A KR100681771B1 (en) 2005-02-01 2005-02-01 Ni-Al alloy anode for molten carbonate fuel cell by in-situ sintering the Ni-Al alloy and Method for preparing the same

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US12/476,779 Division US8415075B2 (en) 2005-02-01 2009-06-02 Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering

Publications (1)

Publication Number Publication Date
US20060171839A1 true US20060171839A1 (en) 2006-08-03

Family

ID=36756757

Family Applications (2)

Application Number Title Priority Date Filing Date
US11/208,903 Abandoned US20060171839A1 (en) 2005-02-01 2005-08-22 Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering the Ni-Al alloy and method for making the same
US12/476,779 Active 2028-04-29 US8415075B2 (en) 2005-02-01 2009-06-02 Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering

Family Applications After (1)

Application Number Title Priority Date Filing Date
US12/476,779 Active 2028-04-29 US8415075B2 (en) 2005-02-01 2009-06-02 Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering

Country Status (2)

Country Link
US (2) US20060171839A1 (en)
KR (1) KR100681771B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2371021A1 (en) * 2008-12-30 2011-10-05 Doosan Heavy Industries & Construction Co., Ltd. Method of manufacturing anode for in-situ sintering for molten carbonate fuel cell
US20170187043A1 (en) * 2015-12-23 2017-06-29 Korea Institute Of Science And Technology Anode for molten carbonate fuel cell having improved creep property, method for preparing the same, and molten carbonate fuel cell using the anode

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100775077B1 (en) 2005-08-19 2007-11-08 경상대학교산학협력단 Positive polar materials and its manufacturing method of Li-secondary battery
KR101158317B1 (en) * 2010-05-03 2012-06-26 두산중공업 주식회사 Preparation method of ternary alloy anode for molten carbonate fuel cell

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5558948A (en) * 1994-11-09 1996-09-24 Energy Research Corporation Fuel cell anode and fuel cell

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4404267A (en) * 1982-04-26 1983-09-13 General Electric Company Anode composite for molten carbonate fuel cell
US5229221A (en) * 1992-04-16 1993-07-20 Electric Power Research Institute, Inc. Methods of making anodes for high temperature fuel cells
KR100259212B1 (en) * 1998-04-29 2000-06-15 윤영석 Method of making the cathode used in mcfc
KR100314513B1 (en) * 1999-10-25 2001-11-30 박호군 An Alloy Anode for Molten Carbonate Fuel Cell and a Process for Production Thereof
KR100480830B1 (en) * 2003-05-06 2005-04-07 한국과학기술연구원 Preparation method of Ni-Al alloy powder for fuel cell using aluminum chloride

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5558948A (en) * 1994-11-09 1996-09-24 Energy Research Corporation Fuel cell anode and fuel cell

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2371021A1 (en) * 2008-12-30 2011-10-05 Doosan Heavy Industries & Construction Co., Ltd. Method of manufacturing anode for in-situ sintering for molten carbonate fuel cell
EP2371021A4 (en) * 2008-12-30 2014-04-16 Doosan Heavy Ind & Constr Method of manufacturing anode for in-situ sintering for molten carbonate fuel cell
US20170187043A1 (en) * 2015-12-23 2017-06-29 Korea Institute Of Science And Technology Anode for molten carbonate fuel cell having improved creep property, method for preparing the same, and molten carbonate fuel cell using the anode
US10276875B2 (en) 2015-12-23 2019-04-30 Korean Institute Of Science And Technology Anode for molten carbonate fuel cell having improved creep property, method for preparing the same, and molten carbonate fuel cell using the anode

Also Published As

Publication number Publication date
US8415075B2 (en) 2013-04-09
US20090238711A1 (en) 2009-09-24
KR100681771B1 (en) 2007-02-15
KR20060088166A (en) 2006-08-04

Similar Documents

Publication Publication Date Title
JP7089494B2 (en) Metal-supported solid oxide fuel cell
EP2843066B1 (en) Catalyst
RU2518061C2 (en) Solid-body oxide fuel elements with internal reforming
JP5689107B2 (en) Manufacturing method of NiO-ceramic composite powder and NiO-ceramic composite fuel electrode
EP1839363B1 (en) Preconditioning treatment to enhance redox tolerance of solid oxide fuel cells
US8415075B2 (en) Ni-Al alloy anode for molten carbonate fuel cell made by in-situ sintering
US8633122B2 (en) Method of manufacturing anode for in-situ sintering for molten carbonate fuel cell
CN110050373B (en) Solid oxide fuel cell anode
US5415833A (en) Method for forming molten carbonate fuel cell anodes
US20100196778A1 (en) Manufacturing method of porous metal electrode for molten carbonate fuel cells using dry process
KR102082691B1 (en) Molten carbonate fuel cells including electrolyte impregnated matrix and methods of manufacturing the same
KR100852759B1 (en) Anode for molten carbonate fuel cell of electrolyte added ni-al alloy and method for preparing the same
KR100314513B1 (en) An Alloy Anode for Molten Carbonate Fuel Cell and a Process for Production Thereof
KR101198851B1 (en) A method for manufacturing an electrolyte-filled electrode for a molten carbonate fuel cell
JP2005158355A (en) Porous electrode for sofc, its manufacturing method and sofc, and pore-forming material for carrying catalyst
KR100516988B1 (en) Manufacturing method of alloy fuel electrode for fuel cell preventing sintering support
KR102243511B1 (en) Water electrolysis electrode and fabrication method thereof
US20050050991A1 (en) Method for manufacturing Ni-Al alloy anode for fuel cells using nickel powders
KR101217787B1 (en) Diffusion preventing material for solid oxide fuel cell, solid oxide fuel cell comprising the same and manufacturing method thereof
JP4232028B2 (en) Fuel electrode for solid oxide fuel cell and method for producing the same
KR101158317B1 (en) Preparation method of ternary alloy anode for molten carbonate fuel cell
EP2621009B1 (en) A porous metal substrate structure for solid oxide fuel cell
KR20000043716A (en) Method for manufacturing a fuel electrode
KR100514782B1 (en) Manufacturing method of pulley process non-oriented electrical steel sheet with low iron loss and high magnetic flux density
Prabhu et al. Preparation and characterization of porous nickel electrodes for molten carbonate fuel cells

Legal Events

Date Code Title Description
AS Assignment

Owner name: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY, KOREA,

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:YOON, SUNG PIL;HONG, SEONG AHN;OH, IN HWAN;AND OTHERS;REEL/FRAME:016915/0671

Effective date: 20050706

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION