Electrode current collector and method for producing same

Abstract

An electrode current collector according to an embodiment of the present disclosure comprises CeO2 and an alloy containing Ni and Cu, and has porosity of 25-80%.

Description

Electrode current collector and method for manufacturing the same

[0001] One embodiment of the present invention relates to an electrode current collector and a method for manufacturing the same, and more particularly, to a current collector having a catalytic function applicable to a solid oxide fuel cell and a co-electrolysis cell and a method for manufacturing the same.

[0002]

[0003] Solid oxide fuel cells (SOFC) and high-temperature co-SOEC cells (Co-SOEC) are attracting attention as future energy technologies for power and fuel production due to their high-temperature operating characteristics, which enable direct use of hydrocarbon fuels, and their high energy conversion efficiency.

[0004] For the fuel electrodes of SOFC and Co-SOEC, a composite of a general nickel metal catalyst and a zirconia-based solid electrolyte, which is an oxygen ion-conducting ceramic, is most widely used.

[0005] However, when using hydrocarbon fuel, coking phenomenon may occur in which carbon is deposited on the surface of the Ni electrode due to incomplete combustion of the fuel. This carbon deposition may reduce the effective surface area required for the electrode reaction, thereby lowering the performance and stability of the cell.

[0006] Therefore, when using hydrocarbon fuel, external pre-reforming equipment is sometimes installed, but using such separate equipment causes additional costs for facility construction and complexity in system configuration, making it difficult to secure economic feasibility of the product.

[0007] Therefore, recent technological developments are being conducted toward finding a method to process fuel directly within the stack where the cells are located without a separate reforming device.

[0008] A method has been proposed to infiltrate a precious metal catalyst such as ruthenium (Ru) or palladium (Pd) into the inside of an existing Ni-based fuel electrode to enable direct decomposition (reformation) of the used fuel inside the fuel electrode of the cell by directly processing the fuel inside the stack.

[0009] However, this method requires a separate additional process during the cell manufacturing process, which not only increases the process cost and worsens economic feasibility, but also makes it difficult to apply it additionally to a cell process that has already been commercialized.

[0010] Therefore, there is a need for new current collectors and manufacturing technologies that can process fuel within the stack while utilizing existing cells without changing the stack design.

[0011] One embodiment of the present invention provides a current collector and method thereof capable of processing fuel within a stack while utilizing existing cells without altering the stack design. Specifically, the present invention provides a current collector with catalytic functionality applicable to solid oxide fuel cells and electrolysis cells, and a method for manufacturing the same.

[0012] An electrode current collector according to one embodiment of the present invention comprises an alloy including Ni and Cu and CeO2, and has a porosity of 25 to 80%.

[0013] An alloy containing Ni and Cu may contain 20 to 50 parts by weight of Ni and 50 to 80 parts by weight of Cu per 100 parts by weight of the alloy.

[0014] For 100 parts by volume of the alloy containing Ni and Cu, 5 to 25 parts by volume of CeO2 may be included.

[0015] A method for manufacturing an electrode current collector according to one embodiment of the present invention comprises the steps of: manufacturing a mixed powder by mixing an alloy powder containing Ni and Cu and CeO2; manufacturing a molded body by applying pressure to the mixed powder; and heat-treating the molded body at 450 to 1000°C.

[0016] The alloy powder may contain 20 to 50 parts by weight of Ni and 50 to 80 parts by weight of Cu per 100 parts by weight of the alloy powder.

[0017] The mixed powder may contain 100 parts by volume of alloy powder and 5 to 25 parts by volume of CeO2.

[0018] A solid oxide fuel cell according to one embodiment of the present invention includes the electrode current collector described above.

[0019] An electrode current collector according to one embodiment of the present invention can reduce the burden of directly processing fuel inside a cell of a solid oxide fuel cell or a co-electrolysis cell using hydrocarbon fuel.

[0020] An electrode current collector according to one embodiment of the present invention can additionally serve as a catalyst for decomposing hydrocarbon fuels such as methane into hydrogen and carbon monoxide.

[0021] According to one embodiment of the present invention, the electrode current collector can also act as a promoter that can activate the catalytic reaction of an alloy material such as CeO2, thereby improving the decomposition reaction of hydrocarbons.

[0022] FIG. 1 is a schematic diagram schematically illustrating a solid oxide fuel cell including an electrode collector according to one embodiment of the present invention.

[0023] FIG. 2 is a schematic diagram showing a schematic mechanism for obtaining an effect from an electrode current collector according to one embodiment of the present invention.

[0024] Figure 3 is a photograph of an electrode collector manufactured in Manufacturing Example 1.

[0025] Figure 4 is a graph of the X-ray diffraction analysis (XRD) results measured in Experimental Example 1.

[0026] Figures 5 to 10 are scanning electron microscope (SEM) photographs obtained in Experimental Example 2.

[0027] Figures 11 to 14 are graphs of the methane reforming rate according to temperature measured in Experimental Example 3.

[0028] Figure 15 is a graph of electrical conductivity according to temperature measured in Experimental Example 4.

[0029] Figures 16 to 21 show the results of analyzing the collector manufactured in Manufacturing Example 2 using SEM-EDS (Energy dispersive X-ray spectroscope, EDS).

[0030] Figures 22 to 24 are graphs of the methane reforming rate by temperature measured in Experimental Example 6.

[0031] The terms first, second, and third, etc., are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "singular" and "comprising" include plural forms as well, unless the context clearly dictates otherwise. The word "comprising" as used herein specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0033] When a part is referred to as being "on" or "over" another part, it can be directly on or over the other part, or there may be other parts intervening. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening.

[0034] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0035] In this specification, the term "combination(s) thereof" described in the expression in the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the expression in the Makushi format, and means including any one or more selected from the group consisting of said components.

[0036] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0037]

[0038] FIG. 1 schematically illustrates a solid oxide fuel cell (100) including an electrode current collector according to one embodiment of the present invention. In the solid oxide fuel cell (100) of FIG. 1, other components than the electrode current collector are identical to those of a general solid oxide fuel cell (100), and FIG. 1 illustrates an example of a solid oxide fuel cell (100), and it is possible to omit or add some components of the solid oxide fuel cell (100) shown in FIG. 1 as needed.

[0039] As shown in FIG. 1, the solid oxide fuel cell (100) includes a fuel electrode separator (20), a fuel electrode current collector (10), a cell (30), an air electrode current collector (40), and an air electrode separator (50). In one embodiment of the present invention, the electrode current collector may be the fuel electrode current collector (10) or the air electrode current collector (40), and more specifically, may be the fuel electrode current collector (10). For convenience, the following description will be given as an example in which the electrode current collector is the fuel electrode current collector (10).

[0040] Specifically, the cell (30) may include a fuel electrode (31, anode), a fuel electrode functional layer (32), an electrolyte (33), and an air electrode (34, cathode).

[0041] Additionally, a separator coating layer (51) may be interposed between the air electrode separator (50) and the air electrode current collector (40).

[0042] In this way, the solid oxide fuel cell (100) is composed of current collectors (10, 40) on both sides of the electrodes for electrical connection between the cell (30) and the metal separator (20, 50). The cell (30) made of a ceramic material is a structure in which a porous fuel electrode (31) and an air electrode (34) where an electrochemical reaction occurs are laminated on both sides with a dense electrolyte (33) in the middle.

[0043] In one embodiment of the present invention, the electrode collector (10) having a catalytic function is a feature, and the other configurations are the same as those of a general solid oxide fuel cell (100), so a detailed description is omitted.

[0044] According to one embodiment of the present invention, the electrode current collector (10) is used only as an electron transporter for transmitting the current produced in the cell (30) to the fuel electrode separator (20), and is provided with an additional function for initiating a chemical reaction required for the fuel electrode (31) by providing a catalytic function to the electrode current collector (10).

[0045] FIG. 2 schematically illustrates the mechanism of an electrode current collector (10) according to one embodiment of the present invention. As shown in FIG. 2, the electrode current collector (10) according to one embodiment of the present invention converts methane (CH4) into carbon monoxide (CO) through catalytic action.

[0046] To this end, the electrode current collector (10) according to one embodiment of the present invention may include an alloy including Ni and Cu and CeO2, and may have a porosity of 25 to 80%.

[0047] An alloy containing Ni and Cu is selected because it has a high methane conversion rate and H2 and CO production rates in a solid oxide fuel cell (100). It is also possible to select other metals, such as Fe, instead of Ni and Cu, but in this case, the methane conversion rate and H2 and CO production rates may be significantly lower.

[0048] Alloys containing nickel and copper have a dense fundamental structure, making it difficult to secure the porosity required for catalytic reactions. By adding ceria (CeO2), sintering of the alloy containing nickel and copper can be suppressed, securing the porosity required for catalytic reactions. Furthermore, ceria (CeO2) itself has the ability to supply oxygen ions, so it can play a role in removing carbon deposits on the fuel electrode surface when using hydrocarbons, converting them to CO and CO2.

[0049] In one embodiment of the present invention, the porosity of the electrode current collector (10) is 25 to 80%. If the porosity is too low, it may be difficult to sufficiently obtain the desired catalytic reaction. If the porosity is too high, problems may occur with the strength of the electrode current collector (10). More specifically, the porosity of the electrode current collector (10) may be 50 to 75%. More specifically, the porosity of the electrode current collector (10) may be 60 to 68%. The porosity can be measured using the Archimedes density measurement method.

[0050] The Archimedean density measurement method is described in detail as follows: The magnitude of the buoyant force experienced by a weight submerged in a fluid is equal to the weight of the fluid displaced by the volume. Therefore, buoyancy can be thought of as the weight of the fluid displaced by an object, which can be calculated by multiplying the volume of the displaced fluid by the fluid's density. Measurements can be made using an Archimedean density measurement kit, which can measure dry weight, submerged weight, and fluid weight.

[0051] Dry weight is the weight of a dry sample that does not contain water. Underwater weight is a method of measuring the weight of a sample immersed in water. The submerged sample experiences a buoyancy equal to the volume of the sample (the portion that is not filled with water) and the volume of its closed pores. Therefore, the weight of a sample under water is the weight of the sample minus the buoyancy. Hydrous weight is the weight of a sample that contains water, and water can only be contained in open pores. Therefore, hydrous weight is the weight of the sample plus the weight of water equal to the volume of its open pores.

[0052] Therefore, the Archimedes density measurement method calculates the dry weight by subtracting the water weight from the functional weight and dividing it by the material theory density.

[0053] The porosity can be affected by conditions such as the addition ratio of CeO2, the pressure during molding during the manufacturing process, and the temperature and time during heat treatment.

[0054] The alloy containing Ni and Cu may contain 20 to 50 parts by weight of Ni and 50 to 80 parts by weight of Cu, based on 100 parts by weight of the alloy. In one embodiment of the present invention, the weight part means a relative weight ratio with respect to a reference weight. If too little Ni is contained, it may be difficult to perform the role of a basic electrode current collector (10). If too little Cu is contained, a problem of excessive carbon deposition may occur. More specifically, the alloy may contain 25 to 35 parts by weight of Ni and 65 to 75 parts by weight of Cu.

[0055] With respect to 100 parts by volume of the alloy containing Ni and Cu, 5 to 25 parts by volume of CeO2 may be included. In one embodiment of the present invention, the volume part means a relative volume ratio with respect to a reference volume. If too little CeO2 is included, it is difficult to sufficiently obtain pore formation and catalytic action due to the addition of CeO2. If too much CeO2 is included, the strength of the electrode current collector (10) may be lowered. More specifically, with respect to 100 parts by volume of the alloy containing Ni and Cu, 10 to 20 parts by volume of CeO2 may be included. More specifically, 10 to 15 parts by volume of CeO2 may be included.

[0056]

[0057] In one embodiment of the present invention, the electrode current collector (10) has excellent electrical conductivity. Specifically, at a temperature of 750°C, the conductivity is 1.0×10 3 S / cm to 1.0×10 4 It can be S / cm.

[0058] A method for manufacturing an electrode current collector (10) according to one embodiment of the present invention includes a step of manufacturing a mixed powder by mixing an alloy powder containing Ni and Cu and CeO2; a step of manufacturing a molded body by applying pressure to the mixed powder; and a step of heat-treating the molded body.

[0059] Below, each step is explained in detail.

[0060] First, an alloy powder containing Ni and Cu and CeO2 are mixed to prepare a mixed powder. At this time, the alloy powder may contain 20 to 50 parts by weight of Ni and 50 to 80 parts by weight of Cu with respect to 100 parts by weight of the alloy powder. In addition, the mixed powder may contain 100 parts by volume of the alloy powder and 5 to 25 parts by volume of CeO2. Since the ratios of Ni and Cu in the alloy powder and the ratios of the alloy powder and CeO2 are the same as those of the electrode current collector (10) described above, redundant descriptions are omitted.

[0061] Next, a molded body is manufactured by applying pressure to the mixed powder. At this time, the pressure applied to the mixed powder is 318 kgf / cm. 2 (31.19 MPa) to 637 kgf / cm 2 (62.49 MPa). If the pressure is too low, it is difficult to manufacture a molded body of an appropriate shape. If the pressure is too high, it is difficult to properly form pores in the electrode current collector (10). More specifically, the pressure applied to the mixed powder is 414 kgf / cm. 2 (40.60 MPa) to 541 kgf / cm 2 (53.05 MPa) can be achieved.

[0062] The molded body can be manufactured in a variety of shapes and sizes, offering a high degree of process flexibility. Furthermore, when applied with technologies like tape casting, it can be scaled up to mass-produce large-area current collectors used in commercial, high-volume stacks.

[0063] Next, the molded body is heat-treated. At this time, the temperature can be 450 to 1000℃. If the temperature is too low, there may be a problem in that the porosity is lower than the target porosity due to heat shrinkage during the SOFC sealing process. If the temperature is too high, there may be a problem in that the appropriate porosity cannot be obtained. More specifically, the temperature can be 800 to 1000℃. The heat treatment process may include an oxidation heat treatment process performed in an oxidizing atmosphere and a reduction heat treatment process performed in a reducing atmosphere. In the oxidation heat treatment, organic substances are burned, and pores are created in this process, which can contribute to the formation of high porosity. The heat treatment time may be 5 to 10 hours for the oxidation heat treatment. In the reduction heat treatment, it varies depending on the temperature to be applied to the SOFC (650 to 1000℃), and may be 3 to 15 hours.

[0064] Hereinafter, preferred embodiments and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0065]

[0066] <Manufacturing Example: Manufacturing of Electrode Current Collector>

[0067] First, the Pezzini method was used to manufacture powders containing Ni and Cu. Copper(Ⅱ) nitrate trihydrate (Cu(NO3)2·3H2O), nickel nitrate hexahydrate (Ni(NO3)2·6H2O), and cerium(Ⅲ) nitrate hexahydrate (Ce(NO3)·6H2O) were dissolved in distilled water according to the ratio. Citric acid was added to facilitate the synthesis, and the pH was adjusted to 7 using ammonium hydroxide. The synthesis was performed at approximately 80℃ until a gel was formed. The gel was heat-treated at approximately 200℃ for 1 hour to form a char containing copper-nickel oxide, thereby manufacturing an alloy powder.

[0068] The char obtained through this was finely ground into powder, placed in a mold of the desired size, and pressed through a press to form a plate, after which oxidation heat treatment (air gas) and reduction heat treatment (H2gas) were performed at 900°C.

[0069] Manufacturing Example 1 (10 vol.% CeO2-Cu) in this way 0.7 Ni 0.3 ), Manufacturing Example 2 (15 vol.% CeO2-Cu 0.7 Ni 0.3 ), Manufacturing Example 3 (20 vol.% CeO2-Cu 0.7 Ni 0.3 ) was manufactured. In addition, using the same method, an electrode current collector was manufactured using pure Cu powder (Comparative Manufacturing Example 1, Cu), an electrode current collector was manufactured using pure Ni powder (Comparative Manufacturing Example 2, Ni), and an electrode current collector was manufactured using Ni and Cu alloy powder without adding cerium(Ⅲ) nitrate hexahydrate (Cerium(Ⅲ) nitrate hexahydrate, Ce(NO3)·6H2O) (Comparative Manufacturing Example 3, Cu0.7 Ni 0.3 ) was performed. Figure 3 shows a photograph of the electrode collector manufactured in Manufacturing Example 1.

[0070]

[0071] Experimental Example 1: XRD Analysis

[0072] The electrode collector manufactured in the manufacturing example was subjected to X-ray diffraction analysis (XRD), and the results are shown in Fig. 4.

[0073] As shown in Fig. 4, both Manufacturing Examples 1 to 3 show a face-centered cubic (FCC) lattice structure, and it can be confirmed that CeO2 exists in the form of an oxide.

[0074] Experimental Example 2: SEM Analysis

[0075] The electrode current collectors manufactured in the manufacturing examples were analyzed using a scanning electron microscope (SEM), and the photographs are shown in FIGS. 5 to 10. FIGS. 5 to 10 show Manufacturing Examples 1 to 3 and Comparative Manufacturing Examples 1 to 3, respectively, in that order.

[0076] As shown in FIGS. 5 to 7, it can be confirmed that the electrode current collectors manufactured in Manufacturing Examples 1 to 3 have pores formed appropriately.

[0077] On the other hand, as shown in FIGS. 8 to 10, it can be confirmed that the electrode current collectors manufactured in Comparative Manufacturing Examples 1 to 3 are sintered into a dense structure without good pore formation.

[0078] Experimental Example 3: Conversion Rate Comparison

[0079] The conversion rate of CH4, the production yield of H2 and CO, and the H2 / CO ratio were measured using a gas chromatography method, and are shown in Figures 11 to 14, respectively.

[0080] To determine the catalytic performance, quantitative and qualitative analyses were performed using gas chromatography. The measurement method was the same as the SOFC measurement, where a sample was placed on an alumina holder and attached using a glass sealing paste mixed with glass powder and a binder, and a quartz tube was used to configure two chambers, in and out. This is similar to the sealing method of SOFC. The reformed gas, after passing the methane-steam mixed gas through the catalyst, had its moisture captured using a cooler and then flowed through a gas chromatograph to detect CH4, CO, CO2, H2, etc. Through quantitative and qualitative analyses using gas chromatography, the conversion rate of CH4, the production yield of H2, CO, and the H2 / CO ratio were measured, and the results are shown in Figures 11 to 14, respectively.

[0081] Methane conversion was obtained at an intermediate temperature of 650 ℃ in Example 1 (10 vol.% CeO2-Cu 0.7 Ni 0.3 ) showed the highest conversion rate of about 39%, and at a high temperature of 850 ℃, Manufacturing Example 2 (15 vol.% CeO2- Cu 0.7 Ni 0.3 ) showed the highest methane conversion rate of 82%.

[0082] Hydrogen production yield (yield) at 650 ℃ was 10 vol.% CeO2-Cu in manufacturing example 1 0.7 Ni 0.3 ) showed the highest hydrogen yield of about 39%, and at 850 ℃, it was the same as Manufacturing Example 1 (10 vol.% CeO2-Cu 0.7 Ni 0.3 ) shows the highest hydrogen yield of 94%.

[0083] The carbon monoxide production yield was 650 ℃ in Manufacturing Example 1 (10 vol.% CeO2-Cu 0.7 Ni 0.3) showed the highest carbon monoxide yield of about 11%, and at 850 ℃, it was the same as Manufacturing Example 1 (10 vol.% CeO2-Cu 0.7 Ni 0.3 ) showed the highest carbon monoxide yield of 74%.

[0084] In this way, it can be confirmed that an electrode collector with optimal hydrocarbon reforming performance in an individual operating environment can be manufactured by controlling the mixing ratio of the metal and oxide constituting the collector.

[0085] Experimental Example 4: Measurement of Electrical Conductivity by Temperature

[0086] In order for a current collector with a catalytic function to replace an existing Ni-based current collector (Comparative Manufacturing Example 2: Ni foam), sufficient electrical conductivity must be secured to maintain current collection efficiency.

[0087] In this case, in a reducing atmosphere of 650°C to 750°C, which is the actual collector utilization condition, Manufacturing Example 1 (10 vol.% CeO2-Cu) 0.7 Ni 0.3 ) was measured and the electrical conductivity of the electrode collector manufactured from it was shown in Fig. 15. As shown in Fig. 15, Manufacturing Example 1 (10 vol.% CeO2-Cu 0.7 Ni 0.3 ) has relatively excellent electrical conductivity (approximately 1.832×10 at 750 ℃) of the electrode collector. 3 It can be confirmed that it is sufficient to be used as a whole house by taking S / cm).

[0088] Experimental Example 5: SEM-EDS Analysis

[0089] Manufacturing Example 2 (15 vol% CeO2-Cu) was prepared using an energy dispersive X-ray spectroscope (EDS) equipped in the SEM equipment. 0.7 Ni 0.3 ) were measured for their components and contents, and the results are shown in Figs. 16 to 21.

[0090] It was confirmed that the composition contained 15.01 wt% of Ni, 58.08 wt% of Cu, 12.44 wt% of Ce, and 4.47 wt% of O.

[0091] Experimental Example 6: Comparison with Fe and Ni alloys

[0092] An electrode current collector was manufactured using the same method as in Manufacturing Example 1, but using iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O) instead of copper(Ⅱ) nitrate trihydrate (Cu(NO3)2·3H2O). This was compared to Manufacturing Example 4 (10 vol% CeO2-Ni 0.7 Fe 0.3 ) was named.

[0093] The methane conversion rate and the yields of hydrogen and carbon monoxide were measured in the same manner as in Experimental Example 4, and are shown in Figures 22 to 24.

[0094] As shown in Figures 22 to 24, it can be confirmed that Manufacturing Example 1 has a significantly superior conversion rate and yield compared to Comparative Manufacturing Example 4.

[0095]

[0096] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

[0097] Accordingly, the actual scope of the present invention is defined by the appended claims and their equivalents.

[0098] [Explanation of symbols]

[0099] 100: solid oxide fuel cell, 10: fuel electrode current collector,

[0100] 20: Fuel electrode separator, 30: Cell,

[0101] 31: fuel electrode, 32: fuel electrode functional layer,

[0102] 33: electrolyte, 34: air electrode,

[0103] 40: Air electrode collector, 50: Air electrode separator,

[0104] 51: Separator coating layer

Claims

1. An alloy containing Ni and Cu and CeO2, An electrode current collector having a porosity of 25 to 80%.

2. In paragraph 1, An electrode current collector comprising the alloy containing Ni and Cu, wherein Ni is 20 to 50 parts by weight and Cu is 50 to 80 parts by weight, based on 100 parts by weight of the alloy.

3. In paragraph 1, An electrode current collector comprising 5 to 25 parts by volume of CeO2 for 100 parts by volume of the alloy comprising Ni and Cu.

4. A step of preparing a mixed powder by mixing an alloy powder containing Ni and Cu and CeO2; A step of manufacturing a molded body by applying pressure to the above mixed powder; and A method for manufacturing an electrode current collector, comprising a step of heat treating the above-mentioned molded body at 450 to 1000°C.

5. In paragraph 4, A method for manufacturing an electrode current collector, wherein the alloy powder contains 20 to 50 parts by weight of Ni and 50 to 80 parts by weight of Cu per 100 parts by weight of the alloy powder.

6. In paragraph 4, A method for manufacturing an electrode current collector, wherein the above mixed powder comprises 100 parts by volume of the above alloy powder and 5 to 25 parts by volume of the above CeO2.

7. A solid oxide fuel cell comprising the electrode collector described in paragraph 1.

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