Anode of solid oxide fuel cell, solid oxide fuel cell, and method for manufacturing solid oxide fuel cell

Abstract

The anode of the solid oxide fuel cell is a first sub-anode layer formed on one side of the electrolyte of the solid oxide fuel cell. The first sub-anode layer has a core made of BZY (Yttria doped Barium Zirconate, BaZr x Y y O z a second sub-fuel electrode layer formed on the first sub-fuel electrode layer, the second sub-fuel electrode layer having a BZY core and including a plurality of second structures with Ni formed on the core surface; and a third sub-fuel electrode layer formed on the second sub-fuel electrode layer, the third sub-fuel electrode layer having a BZY core and including a plurality of third structures with Ni formed on the core surface. The weight percentage of the first sub-fuel electrode layer of the first structure is smaller than the weight percentage of the second sub-fuel electrode layer of the second structure, and the weight percentage of the second sub-fuel electrode layer of the second structure is smaller than the weight percentage of the third sub-fuel electrode layer of the third structure.

Description

[Technical Field]

[0001] The present invention relates to a solid oxide fuel cell (SOFC) and a method for manufacturing the SOFC. x Y y O z The present invention relates to an SOFC having an anode containing copper (Cu) and nickel (Ni), and a method for manufacturing the SOFC. The anode of the present invention includes functionally graded layers (FGLs) having a triple phase boundary (TPB) length. [Background technology]

[0002] The primary function of an SOFC anode is to provide a site for the electrochemical oxidation of fuel. The anode material must be stable in the reducing atmosphere of the fuel and possess sufficient electronic conductivity and catalytic reactivity to react with the fuel gas at operating temperatures. Because SOFCs operate at high temperatures between 600°C and 1000°C, the anode must maintain thermal and chemical compatibility with other components at room temperature, operating temperatures, and even higher temperatures, such as the SOFC manufacturing temperature. When using a nickel-yttria stabilized zirconia (Ni-YSZ) cermet anode for hydrocarbon fuels, carbon deposition increases by more than 12% by weight, leading to anode failure. Therefore, reducing the amount of carbon deposition is important. Reducing the Ni content of Ni-YSZ anodes can decrease electrical conductivity, while reducing the YSZ content can decrease ionic conductivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Korean Patent Registration No. 10-1111224 [Patent Document 2] Korean Patent Registration No. 10-1602157 [Patent Document 3] Korean Patent Registration No. 10-2035735 [Patent Document 4] Korean Patent Publication No. 10-2010-0118256 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides an SOFC anode that reduces carbon deposition while maintaining the electrical conductivity of Ni and YSZ in a Ni-YSZ anode, a fuel cell having the anode, and a method for manufacturing the same. [Means for solving the problem]

[0005] In one embodiment of the present invention, the anode of the solid oxide fuel cell comprises a first sub-anode layer formed on one side of the electrolyte of the solid oxide fuel cell. The first sub-anode layer has a core made of BZY (Yttria doped Barium Zirconate, BaZr x Y y O z a second sub-fuel electrode layer formed on the first sub-fuel electrode layer, the second sub-fuel electrode layer having a BZY core and including a plurality of second structures with Ni formed on the core surface; and a third sub-fuel electrode layer formed on the second sub-fuel electrode layer, the third sub-fuel electrode layer having a BZY core and including a plurality of third structures with Ni formed on the core surface. The weight % of the first sub-fuel electrode layer of the first structure is smaller than the weight % of the second sub-fuel electrode layer of the second structure, and the weight % of the second sub-fuel electrode layer of the second structure is smaller than the weight % of the third sub-fuel electrode layer of the third structure.

[0006] In one embodiment, the second sub-fuel electrode layer and the third sub-fuel electrode layer further include yttria stabilized zirconia (YSZ).

[0007] In one embodiment, the second sub-fuel electrode layer and the third sub-fuel electrode layer further include nickel oxide (NiO).

[0008] In one embodiment of the present invention, a solid oxide fuel cell includes an electrolyte, a cathode formed on a first surface of the electrolyte, and an anode formed on a second surface of the electrolyte opposite the first surface. The anode includes a first sub-anode layer formed on one side of the electrolyte of the solid oxide fuel cell—the first sub-anode layer having a BZY core and including a plurality of first structures with Ni formed on the core surface—and a second sub-anode layer formed on the first sub-anode layer—the second sub-anode layer having a BZY core and including a plurality of second structures with Ni formed on the core surface. The weight percentage of the first structures in the first sub-anode layer is smaller than the weight percentage of the second structures in the second sub-anode layer.

[0009] In one embodiment, the method further comprises a third sub-fuel electrode layer formed on the second sub-fuel electrode layer - the third sub-fuel electrode layer having BZY as a core and including a plurality of third structures each having Ni formed on the core surface -, wherein the weight percentage of the second structures in the second sub-fuel electrode layer is smaller than the weight percentage of the third structures in the third sub-fuel electrode layer.

[0010] In one embodiment, the second sub-anode layer and the third sub-anode layer further comprise YSZ.

[0011] In one embodiment, the second sub-anode layer and the third sub-anode layer further contain NiO.

[0012] In one embodiment of the present invention, a method for manufacturing a solid oxide fuel cell includes the steps of: preparing an electrolyte containing YSZ; coating a first surface of the electrolyte with a first mixture slurry containing NiO, YSZ, and a first catalyst in which Ni is formed on a BZY core; coating the first mixture slurry with a second mixture slurry containing NiO, YSZ, and a second catalyst in which Ni is formed on a BZY core, the weight percentage of the second catalyst being greater than that of the first catalyst; coating the second mixture slurry with a third mixture slurry containing a third catalyst in which Ni is formed on a BZY core, the weight percentage of the third catalyst being greater than that of the second catalyst; sintering the electrolyte coated with the first, second, and third mixture slurries to form a first sub-anode layer, a second sub-anode layer, and a third sub-anode layer on the first surface of the electrolyte; and forming a cathode on a second surface of the electrolyte opposite the first surface.

[0013] In one embodiment, the first to third mixture slurries further contain a pore-forming agent, and the weight percentage of the pore-forming agent contained in the first and second mixture slurries is less than the weight percentage of the pore-forming agent contained in the third mixture slurry. [Effects of the Invention]

[0014] Nano-sized Ni is coated onto BZY ceramic powder, which has proton and ion conductivity, as a catalyst for hydrocarbon fuel cells. This is then used to create a functional gradient layer on the Ni-YSZ fuel electrode, which can be put to practical use using hydrocarbon fuels. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is an example of a single cell of an SOFC according to one embodiment of the present invention. [Figure 2] 2 is an example of an anode according to one embodiment of the present invention. [Figure 3a-3b] 1 is a conceptual diagram of a portion of an anode according to one embodiment of the present invention. [Figure 4]1 is a flow diagram of a method for manufacturing an SOFC according to one embodiment of the present invention. [Figure 5] 1 is a graph comparing the voltage and power density according to the total area specific resistance of a single cell of an SOFC according to one embodiment of the present invention and a single cell of a conventional SOFC. [Figure 6] 1 is a graph of the voltage and power density of a single cell of a SOFC according to one embodiment of the present invention and a single cell of a conventional SOFC. [Figure 7] 1 is a graph showing the voltage change over time of a single cell of an SOFC according to one embodiment of the present invention and a single cell of a conventional SOFC. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below with reference to the drawings. In the description of the present invention, if a detailed description of related known functions or configurations is deemed to unnecessarily deviate from the gist of the present invention, such detailed description will be omitted. It should be noted that the following examples may be modified in various ways, and the scope of the technical concept of the present invention is not limited to the following examples. Rather, these embodiments are provided to more faithfully and completely complete the present invention and to fully convey the technical concept of the present invention to those skilled in the art.

[0017] It should be understood that the technology described in the present invention is not intended to be limited to a particular embodiment, but includes various modifications, equivalents, and / or alternatives to the embodiments of the present invention.

[0018] In the description of the drawings, like components may use like reference numerals.

[0019] In the present invention, expressions such as "having," "having," "can have," "include," or "can include" refer to the presence of a corresponding feature (e.g., a value, a function, an operation, or a component such as a part) and do not exclude the presence of additional features. In the present invention, expressions such as "A or B," "at least one of A and / or B," or "one or more of A and / or B" can include all possible combinations of the items listed together. For example, "A or B," "at least one of A and B," or "at least one of A or B" can refer to all of the following: (1) including at least one A, (2) including at least one B, or (3) including at least one A and at least one B.

[0020] As used herein, expressions such as "first," "second," "first," or "second" can modify various components regardless of order and / or importance, and are only used to distinguish one component from another, and do not limit the corresponding component.

[0021] When a component (e.g., a first component) is described as being "operatively or communicatively coupled with / to" or "connected" to another component (e.g., a second component), it should be understood that the component can be directly connected to the other component or can be connected through another component (e.g., a third component). On the other hand, when a component (e.g., a first component) is described as being "directly coupled" or "directly connected" to another component (e.g., a second component), it should be understood that there is no other component (e.g., a third component) between the component and the other component.

[0022] As used herein, the expression “configured to” can be used interchangeably with, for example, “suitable for,” “having the capacity to,” “designed to,” “adapted to,” “made to,” or “capable of,” depending on the context. The term “configured to” does not necessarily mean “specifically designed to” in terms of hardware. Instead, in some contexts, the phrase “apparatus configured to” can mean that the apparatus is “capable of” working with other devices or components. For example, the phrases “a processor configured or configured to execute A, B, and C” and “a module configured or configured to execute A, B, and C” can refer to a dedicated processor for performing the corresponding operations (e.g., an embedded processor) or to a general-purpose processor (e.g., a CPU or application processor) that performs the operations by executing one or more software programs stored in a memory device.

[0023] The documents mentioned in the prior art of the present invention are hereby incorporated by reference in their entirety.

[0024] FIG. 1 shows an example of an SOFC unit cell 100 according to one embodiment of the present invention. Referring to FIG. 1, the SOFC unit cell 100 includes a cathode 110, an electrolyte 120, and an anode 130. The cathode 110 is also called the anode, and the anode 130 is also called the cathode. Generally, oxygen adsorbed on the surface of the cathode 110 moves to the electrolyte 120 through dissociation / surface diffusion, gaining electrons and becoming oxygen ions. The generated oxygen ions then move to the anode 130 via the electrolyte 120. The oxygen ions diffused in the anode 130 react with hydrogen to release electrons and simultaneously generate water and heat.

[0025] In one embodiment, among the components of the SOFC cell 100, the air electrode 110 has high ionic conductivity and electronic conductivity (50 (Ω·cm) -1 The cathode material may have a porous film (30% or more) that is stable in an oxidizing atmosphere, does not react chemically with or interdiffuse with other components, and has a similar thermal expansion coefficient. For example, materials used for the cathode include LaMnO3, LaCoO3, LSCF, and LSC. The cathode material may have a perovskite structure.

[0026] In one embodiment, the electrolyte 120 must be thermochemically stable over a wide range of temperatures and redox atmospheres, have high ionic conductivity, and low electronic conductivity. It also forms a thin, strong film to prevent gas leakage. For example, the electrolyte 120 can be made of yttria-stabilized zirconia (YSZ), an oxygen ion conductor with a fluorite structure. Alternatively, the electrolyte 120 can be made of a ceria-based material, such as Ga-doped ceria (0.07 S / cm at 800°C) or Sm-doped ceria (0.11 S / cm at 800°C), or a LaGaO or Bi2O3-based material, which have high ionic conductivity. The electrolyte 120 can also be made by combining the ionic conductor YSZ with transition metals, such as Co and Ni, which are electronic conductors. Ni has excellent catalytic properties and electronic conductivity, and YSZ disperses in Ni, allowing for sintering behavior control and the creation of a three-phase interface. To obtain optimum electrode properties, certain strength and porosity must be imparted, and uniform dispersion is necessary to ensure long-term stability in an oxidation-reduction atmosphere.

[0027] In one embodiment, the anode 130 includes a functional gradient layer. In one example, the functional gradient layer has a gradually changing composition or structure to achieve desired properties. For example, the functional gradient layer may include multiple layers stacked together, each having a different composition or structure. In the present invention, each of the multiple layers included in the functional gradient layer is referred to as a sub-anode layer. In one example, the anode 130 may include a structure having a BZY (Yttria-doped Barium Zirconate, BaZrxYyOz) core and nickel (Ni) deposited, coated, or formed on the surface of the core. When nickel (Ni) is deposited, coated, or formed on the BZY surface, oxygen and nickel react to form a NiO coating. Therefore, in the present invention, a structure in which Ni is deposited, coated, or formed on the BZY surface is referred to as Ni / BZY or NiO / BZY. For example, in the present invention, Ni / BZY can be interchangeably referred to as NiO / BZY, and NiO / BZY can be interchangeably referred to as Ni / BZY. The anode 130 may further contain NiO and YSZ in addition to Ni / BZY or NiO / BZY.

[0028] FIG. 2 is an example of an anode 130 according to one embodiment of the present invention.

[0029] Referring to FIG. 2 , the anode 130 includes a first sub-anode layer 132, a second sub-anode layer 134, and a third sub-anode layer 136. For illustrative purposes, three sub-anode layers are shown as an example, but the number of sub-anode layers is not limited to three. That is, the anode 130 may include two sub-anode layers or four or more sub-anode layers. In one example, the first sub-anode layer 132 may include NiO, YSZ, and NiO / BZY. The second sub-anode layer 134 may include NiO, YSZ, and NiO / BZY. The third sub-anode layer 136 may include YSZ and NiO / BZY. Furthermore, the third sub-anode layer 136 may include NiO, YSZ, and NiO / BZY. Pores may be formed in the first sub-anode layer 132, the second sub-anode layer 134, and the third sub-anode layer 136. The pores in the first sub-fuel electrode layer 132, the second sub-fuel electrode layer 134, and the third sub-fuel electrode layer 136 can also be expressed in weight percent. In one example, the porosity in the first sub-fuel electrode layer 132, the second sub-fuel electrode layer 134, and the third sub-fuel electrode layer 136 is approximately 35% to 45%. That is, the porosity of the anode layer 130 can be approximately 35% to 45%.

[0030] A first surface of the first sub-fuel layer 132 can be in contact with the electrolyte 120. One surface of the first sub-fuel layer 132 can be in direct contact with the electrolyte 120. A second surface of the first sub-fuel layer 132 opposite the first surface of the first sub-fuel layer 132 can be in contact with a first surface of the second sub-fuel layer 134. A second surface of the second sub-fuel layer 134 opposite the first surface of the second sub-fuel layer 134 can be in contact with a first surface of the third sub-fuel layer 136.

[0031] In one embodiment, the first sub-fuel layer 132, the second sub-fuel layer 134, and the third sub-fuel layer 136 may have different compositions. The weight percentages of NiO, YSZ, and NiO / BZY contained in the first sub-fuel layer 132, the second sub-fuel layer 134, and the third sub-fuel layer 136 may be different. The weight percentages of at least one of NiO, YSZ, and NiO / BZY contained in the first sub-fuel layer 132, the second sub-fuel layer 134, and the third sub-fuel layer 136 may be different. The weight percentages of at least one of NiO, YSZ, and NiO / BZY contained in the first sub-fuel layer 132, the second sub-fuel layer 134, and the third sub-fuel layer 136 may be the same. The weight percentage of at least one of NiO, YSZ, and NiO / BZY contained in at least two of the first sub-fuel layer 132, the second sub-fuel layer 134, and the third sub-fuel layer 136 may be the same.

[0032] In one example, the weight percentage of NiO / BZY may increase in the first sub-fuel layer 132, the second sub-fuel layer 134, and the third sub-fuel layer 136 as they move away from the electrolyte 120. That is, the weight percentage of NiO / BZY in the second sub-fuel layer 134 may be greater than the weight percentage of NiO / BZY in the first sub-fuel layer 132, and the weight percentage of NiO / BZY in the third sub-fuel layer 136 may be greater than the weight percentage of NiO / BZY in the second sub-fuel layer 134.

[0033] In one embodiment, the weight percentage of YSZ in the first sub-fuel layer 132, the second sub-fuel layer 134, and the third sub-fuel layer 136 may decrease the farther they are from the electrolyte 120. That is, the weight percentage of YSZ in the second sub-fuel layer 134 may be smaller than the weight percentage of YSZ in the first sub-fuel layer 132, and the weight percentage of YSZ in the third sub-fuel layer 136 may be smaller than the weight percentage of YSZ in the second sub-fuel layer 134.

[0034] In one embodiment, the NiO content of the sub-anode layer farthest from the electrolyte 120 can be 0. In one embodiment, the YSZ content of the sub-anode layer farthest from the electrolyte 120 can be 0. In one embodiment, the sub-anode layer farthest from the electrolyte 120 can include only NiO / BZY.

[0035] In one embodiment, the porosity of the first, second, and third sub-anode layers may be substantially the same or similar. Conversely, the porosity of the first, second, and third sub-anode layers may be different.

[0036] 3a and 3b are conceptual diagrams of a portion 300 of an anode 130 according to one embodiment of the present invention.

[0037] 3a and 3b, a portion 300 of the anode 130 may be any one of the first sub-anode layer 132, the second sub-anode layer 134, and the third sub-anode layer 136. Therefore, the portion 300 of the anode 130 may be referred to as a sub-anode layer 300. The sub-anode layer 300 may include NiO / BZY 310 and other components 320. The other components 320 are not shown and are indicated by blank spaces. In one embodiment, the other components 320 may include NiO, YSZ, and pores.

[0038] In one embodiment, NiO / BZY310 includes BZY312 and NiO314. NiO314 can be formed on the surface of BZY312. BZY312 can be in the shape of a circular or polygonal column extending in one direction, such as a pallet, sphere, or aspherical shape. That is, although BZY312 is conceptualized as a pallet in FIG. 3a and as a sphere in FIG. 3b, various other shapes may be used.

[0039] In one embodiment, BZY312 may be in a form produced when BZY is produced as a powder. For example, NiO / BZY310 may be a catalyst in which Ni is coated on BZY structures in various shapes, such as pellets, spheres, non-spherical structures, cylinders, and polygonal pillars, produced by extrusion molding BZY powder produced by a solid-state method.

[0040] The inventors of the present invention prepared a Ni / BZY catalyst as follows: However, the present invention is not limited to such a method.

[0041] The BZY powder was produced by the solid-phase method. Specifically, BaCO3 (99.9%), ZrO2 (99.9%), Y2O3 (99.9%) and acetone were mixed and homogenized, and then dried at 110°C. The dried powder was subjected to attrition milling and then heat-treated in an air atmosphere at 1150°C. The produced BZY powder had a specific surface area of ​​10-20 m 2 The present invention utilizes the method of a prior patent (Korean Patent Registration No. 10-2035735), and more detailed information may be found in the prior patent.

[0042] The precursor for Ni deposition in the temperature-controlled chemical vapor deposition reaction is Ni(Cp)2, which is injected at 5 wt% to 30 wt% of the weight of the BZY support (BZY powder) to control the amount of Ni coated on the surface. For Ni deposition, Ni vapor in the form of an organometallic compound sublimated at a temperature of 250°C reacted with oxygen in the air on the BZY support surface to coat it in the form of NiO, producing a NiO / BZY catalyst. NiO / BZY can be used to form Ni / BZY through in-situ reduction.

[0043] FIG. 4 is a flow diagram of a method for manufacturing an SOFC according to one embodiment of the present invention.

[0044] Referring to FIG. 4, an electrolyte is prepared (S405). A first sub-fuel electrode layer is formed on the prepared electrolyte (S410). In one embodiment, the first sub-fuel electrode layer is formed by coating a slurry for the first sub-fuel electrode layer on the electrolyte using, for example, a screen printing method and drying the coating. A second sub-fuel electrode layer is formed on the dried slurry for the first sub-fuel electrode layer (S415). In one embodiment, the second sub-fuel electrode layer is formed by coating a slurry for the second sub-fuel electrode layer on the first sub-fuel electrode layer using, for example, a screen printing method and drying the coating. A third sub-fuel electrode layer is formed on the dried slurry for the second sub-fuel electrode layer (S420). The third sub-fuel electrode layer is formed by coating a slurry for the third sub-fuel electrode layer on the second sub-fuel electrode layer using, for example, a screen printing method and drying the coating. The dried first sub-fuel electrode layer slurry, the dried second sub-fuel electrode layer slurry, and the dried third sub-fuel electrode layer slurry are sintered at a temperature between 1,000°C and 1,300°C for a set time to form the first sub-fuel electrode layer, the second sub-fuel electrode layer, and the third sub-fuel electrode layer. A cathode is formed on the third sub-fuel electrode layer (S425). The third sub-fuel electrode layer is coated with the cathode slurry and sintered at a temperature between 1,000°C and 1,300°C for a set time to form the cathode.

[0045] It is understood that in one embodiment, the cathode may be formed before the first to third anodes.

[0046] To measure and analyze the electrochemical characteristics of a SOFC cell incorporating the anode of the present invention, the following cell was fabricated. The electrolyte support was made by compressing YSZ powder and then sintering it at 1,400°C for 5 hours to obtain a dense, disk-shaped electrolyte support with a diameter of 18 mm and a thickness of 200 μm. The sub-anode layer slurry was prepared by mixing NiO, YSZ, and the NiO / BZY (see Table 1 below) with the organic binders ethyl cellulose and α-terpineol. Graphite (7-10 μm) was used as the pore-forming agent. Materials other than NiO, YSZ, and NiO / BZY, the main anode materials, can be replaced with other materials.

[0047] [Table 1]

[0048] The reason why the slurries for the first and second sub-fuel layers contain 5 wt% of pore-former and the slurry for the third sub-fuel layer contains 10 wt% of pore-former is that when the slurries for the first and second sub-fuel layers are used to form the first and second sub-fuel layers, NiO is reduced and pores are formed at oxygen sites when Ni is formed. Therefore, although the ratio of pore-former contained in the slurries for the first and second sub-fuel layers and the third sub-fuel layer is different, the porosity of the first, second, and third sub-fuel layers after sintering can be substantially the same or similar.

[0049] The slurry for the first sub-fuel electrode layer was coated on the electrolyte support and dried for 30 minutes, the slurry for the second sub-fuel electrode layer was coated and dried for 30 minutes, and the slurry for the third sub-fuel electrode layer was coated and dried for 30 minutes. After that, it was sintered at 1,300°C for 2 hours. The slurry for the air electrode was also composed of an organic binder and La. 0.6 Sr 0.4 Co 0.2 Fe 0.8 The electrode slurry was prepared by mixing O3 (LSCF) and YSZ in a weight ratio of 5:5. The electrode slurry was coated onto an electrolyte support by screen printing. The button cell with the coated electrode was then finally sintered at 1,150°C for 2 hours. After sintering, the total thickness of the anode layer was confirmed to be 40 μm. Each sub-anode layer had a thickness of approximately 10-15 μm, indicating good adhesion without any peeling. The NiO in the anode layer was reduced to Ni via in-situ reduction at 800°C before use. The porosity of the anode layer is preferably approximately 35-45%. SEM image analysis of the anode layer sintered at 1,300°C showed a porosity of 37.2% after reduction at 800°C, confirming suitability.

[0050] FIG. 5 is a graph comparing the voltage and power density as a function of total area specific resistance of a single cell of an SOFC according to one embodiment of the present invention and a single cell of a conventional SOFC.

[0051] Referring to Figure 5, the results of measuring the change in voltage and power density depending on the area specific resistance (ASR) using impedance spectroscopy can be seen. "FGLs" is the cell according to the present invention, and Ni-YSZ is the conventional cell. At 800°C, the area specific resistance (ASR) of the cell according to the present invention is about 0.2 Ω cm. 2 Overall, the total ASR of the cell according to the present invention was lower than that of a conventional Ni-YSZ cell depending on the operating temperature. This is because the nano-Ni contained in Ni / BZY increases the total Ni content, and Ni percolation due to penetration of the Ni lattice inside the anode increases. In addition, because BZY is a hybrid conductor that has both proton and ion conductivity, it can replace YSZ, an ionic conductor, even if the amount of YSZ is reduced. Therefore, it can be seen that the cell according to the present invention can be applied to commercially available fuel cells.

[0052] FIG. 6 is a graph of the voltage and power density of a single cell of a SOFC according to one embodiment of the present invention and a single cell of a conventional SOFC.

[0053] Referring to Figure 6, when using CH4 fuel and the operating temperature of 800°C, the conventional Ni-YSZ battery has a power output of 0.38 W / cm 2 The single cell according to the present invention exhibited a maximum power density of 0.44 W / cm 2 It was confirmed that the performance of the cell according to the present invention was approximately 20% higher than that of the conventional Ni-YSZ, and this is believed to be because the addition of Ni / BZY to the anode layer increased the catalytic activity for suppressing carbon deposition, reducing carbon deposition and allowing fuel to be smoothly supplied to the three-phase interface.

[0054] FIG. 7 is a graph showing the voltage change over time for a single cell of the SOFC according to one embodiment of the present invention and a single cell of a conventional SOFC.

[0055] Referring to FIG. 7, the conventional Ni-YSZ cell has a current of 0.41 A / cm 2As a result of long-term operation at 800°C using CH4 fuel, it was confirmed that the voltage of the conventional Ni-YSZ electrode decreased after about 20 minutes due to carbon deposition. On the other hand, the cell of the present invention had a current of 0.45 A / cm 2 Despite operating at an operating temperature of 800°C for more than 50 hours, there was almost no change in voltage and power density.

[0056] This shows that the cell according to the present invention ensures electrical conductivity and optimizes resistance to hydrocarbons, improving the durability of the fuel cell.

[0057] Although the embodiments have been described above with limited drawings, those skilled in the art may apply various technical modifications and changes based on the above content. For example, suitable results may be achieved by performing the described techniques in a different order than described, and / or by combining or combining the components of the described systems, structures, devices, circuits, etc. in a different manner than described, or by substituting or replacing them with other components or equivalents.

[0058] Accordingly, other embodiments, examples, and equivalents of the claims are within the scope of the following claims.

Claims

1. In the anode of a solid oxide fuel cell, The first sub-anode layer formed on one side of the electrolyte of the solid oxide fuel cell is made of BZY (Yttrium-doped Barium Zirconate, BaZr ｘ Y ｙ O ｚ ) and includes a plurality of first structures having nickel (Ni) formed on the surface of the core; a second sub-fuel electrode layer formed on the first sub-fuel electrode layer, the second sub-fuel electrode layer including a plurality of second structures each having a BZY core and Ni formed on a surface of the core; and a third sub-fuel electrode layer formed on the second sub-fuel electrode layer, the third sub-fuel electrode layer including a plurality of third structures each having a BZY core and Ni formed on a surface of the core; a weight percentage of the first sub-fuel electrode layer of the first structure is smaller than a weight percentage of the second sub-fuel electrode layer of the second structure, and a weight percentage of the second sub-fuel electrode layer of the second structure is smaller than a weight percentage of the third sub-fuel electrode layer of the third structure, Anode of a solid oxide fuel cell.

2. the second sub-fuel electrode layer and the third sub-fuel electrode layer further contain yttria stabilized zirconia (YTZ); The anode of a solid oxide fuel cell according to claim 1 .

3. the second sub-fuel electrode layer and the third sub-fuel electrode layer further contain nickel oxide (NiO); The anode of a solid oxide fuel cell according to claim 1 .

4. In solid oxide fuel cells, electrolyte; a cathode formed on a first surface of said electrolyte; an anode formed on a second surface of the electrolyte opposite to the first surface, the anode comprising: a first sub-anode layer formed on one side of the electrolyte of the solid oxide fuel cell, the first sub-anode layer having a BZY core and including a plurality of first structures with Ni formed on the core surface; and a second sub-anode layer formed on the first sub-anode layer, the second sub-anode layer having a BZY core and including a plurality of second structures with Ni formed on the core surface; the weight percentage in the first sub-fuel electrode layer of the first structure is smaller than the weight percentage in the second sub-fuel electrode layer of the second structure; Solid oxide fuel cell.

5. a third sub-fuel electrode layer formed on the second sub-fuel electrode layer, the third sub-fuel electrode layer including a plurality of third structures each having a BZY core and Ni formed on a surface of the core; the weight percentage in the second sub-fuel electrode layer of the second structure is smaller than the weight percentage in the third sub-fuel electrode layer of the third structure; The anode of a solid oxide fuel cell according to claim 4.

6. the second sub-fuel electrode layer and the third sub-fuel electrode layer further contain YSZ; The fuel electrode of a solid oxide fuel cell according to claim 5 .

7. the second sub-fuel electrode layer and the third sub-fuel electrode layer further contain NiO; The fuel electrode of a solid oxide fuel cell according to claim 5 .

8. 1. A method for manufacturing a solid oxide fuel cell, comprising: providing an electrolyte comprising YSZ; coating a first surface of the electrolyte with a first mixture slurry including NiO, YSZ, and a first catalyst formed of Ni on a BZY core; coating the first mixture slurry with a second mixture slurry containing a second catalyst formed of NiO, YSZ, and Ni on a BZY core, the weight percentage of the second catalyst being greater than the weight percentage of the first catalyst; coating the second mixture slurry with a third mixture slurry containing a third catalyst formed of Ni on a BZY core, the weight percentage of the third catalyst being greater than the weight percentage of the second catalyst; sintering the electrolyte coated with the first, second, and third mixture slurries to form a first sub-anode layer, a second sub-anode layer, and a third sub-anode layer on a first surface of the electrolyte; and forming a cathode on a second surface of the electrolyte opposite the first surface; A method for manufacturing a solid oxide fuel cell.

9. The first to third mixture slurries further contain a pore-forming agent, the weight percent of the pore-forming agent contained in the first and second mixture slurries is less than the weight percent of the pore-forming agent contained in the third mixture slurry; The method for producing a solid oxide fuel cell according to claim 8 .

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