KR20200036266A - Air electrode current collector for solid oxide fuel cell and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a cathode current collector for a solid oxide fuel cell in a core-shell structure comprising: a core unit made of a metal mesh; and a shell unit provided on a surface of the core unit and containing platinum or gold. The present invention also relates to a manufacturing method thereof. According to the present invention, it is possible to prevent the performance degradation of batteries due to contamination of a cathode surface.

Description

Air cathode current collector for solid oxide fuel cell and its manufacturing method {AIR ELECTRODE CURRENT COLLECTOR FOR SOLID OXIDE FUEL CELL AND MANUFACTURING METHOD THEREOF}

The present application relates to an anode current collector for a solid oxide fuel cell and a method for manufacturing the same.

Recently, as the depletion of existing energy resources such as oil and coal is predicted, interest in energy that can replace them is increasing. As one of these alternative energies, fuel cells are particularly attracting attention due to advantages such as high efficiency, no emission of pollutants such as NOx and SOx, and abundant fuel used.

A fuel cell is a power generation system that converts chemical reaction energy of a fuel and an oxidant into electrical energy, and hydrocarbons such as hydrogen, methanol, and butane are used as fuel, and oxygen is used as an oxidant.

Fuel cells include polymer electrolyte fuel cells (PEMFC), direct methanol fuel cells (DMFC), phosphoric acid fuel cells (PAFC), alkaline fuel cells (AFC), molten carbonate fuel cells (MCFC), and solid oxide fuel And SOFCs.

In general, SOFC has a stack structure in which a plurality of unit cells (electrodes) and an anode (cathode) and an anode (anode) located on both sides of the electrolyte are stacked to generate high power. A separator plate is used to combine the unit cells in a stack structure, and a current collector is inserted between the unit cell and the separator plate to improve the current collecting function. The current collector collects electricity generated from the cells that actually generate electricity and delivers it to the next stage.

The current collector is a major component related to SOFC performance, and research on the current collector has been continuously conducted.

Korea Patent Publication No. 2012-0110787

The present application is to provide a cathode current collector for a solid oxide fuel cell and a method for manufacturing the same.

One embodiment of the present application,

A core portion made of a metal mesh; And

Provided is a cathode current collector for a solid oxide fuel cell having a core-shell structure, which is provided on the surface of the core portion and includes a shell portion including platinum (Pt) or gold (Au).

In addition, an exemplary embodiment of the present application,

Anode;

An electrolyte layer provided on the anode;

An air electrode provided on the electrolyte layer; And

It provides a solid oxide fuel cell including the cathode current collector provided on the cathode.

In addition, an exemplary embodiment of the present application,

It provides a method of manufacturing a cathode current collector for a solid oxide fuel cell comprising the step of forming a shell portion by coating platinum (Pt) or gold (Au) on the surface of the core portion made of a metal mesh.

The cathode current collector for a solid oxide fuel cell according to an exemplary embodiment of the present application has an effect of preventing sublimation of a metal mesh by introducing a core-shell structure, thereby preventing the performance degradation of the battery due to contamination of the cathode surface.

1 is a view showing a cathode current collector for a solid oxide fuel cell according to an exemplary embodiment of the present application.
2 is a view showing the structure of a solid oxide fuel cell according to an exemplary embodiment of the present application.
3 is a view of the appearance of silver deposited on the surface of the cathode.
4 is a diagram schematically showing the principle of electricity generation in a solid oxide fuel cell.

Hereinafter, preferred embodiments of the present application will be described. However, the embodiments of the present application may be modified in various other forms, and the scope of the present application is not limited to the embodiments described below. In addition, the embodiments of the present application are provided to more fully describe the present application to those skilled in the art.

When a member is referred to as being “on” another member in the present specification, this includes not only the case where one member abuts another member, but also another member between the two members.

In the present specification, when a part “includes” a certain component, this means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

When metal ions are diffused in the metal mesh used as the material of the cathode current collector, this causes a change in the metal composition in the mesh, which decreases the durability of the current collecting layer itself, and also precipitates the metal by the reduction reaction of the metal ions. It can interfere with the flow. For example, when Ag mesh is introduced into the current collector, Ag diffused from the Ag mesh has a property of stabilizing with Ag oxide, so when the potential of electrons increases in the vicinity, Ag ⁺ ions meet with the electrons and are shown in FIG. 3. as the silver is precipitated on the cathode surface it can interfere with the flow of gas ^{(Ag + + 2e - → Ag} ).

Accordingly, the inventors of the present invention use a metal mesh as the core portion 500 as shown in FIG. 1, and form a shell portion 501 by coating platinum (Pt) or gold (Au) on all surfaces of the core portion to form a core-shell structure. The problem of sublimation of metal from a metal mesh was solved by preparing a cathode current collector.

The cathode current collector for a solid oxide fuel cell according to an exemplary embodiment of the present application includes a core portion formed of a metal mesh; And a shell portion provided on the surface of the core portion and including a shell portion including platinum (Pt) or gold (Au). When the cathode current collector has a core-shell structure, since a coating layer is formed on all surfaces constituting the cathode current collector, there is an advantage of completely preventing sublimation of the metal mesh compared to when only one layer is formed.

In one embodiment of the present application, the mesh means that the metal wires cross each other and are formed in a lattice form, and the wire diameter and wire height of the metal wire are preferably 0.1 mm to 0.2 mm. . The grid includes 50 to 70 per square inch.

In an exemplary embodiment of the present application, the metal mesh may be an Ag mesh, and the silver mesh has an advantage of being low cost and high conductivity compared to other metal meshes used as current collectors.

In an exemplary embodiment of the present application, the shell portion may include platinum (Pt) or gold (Au), and preferably may include platinum (Pt). Platinum is suitable as a metal forming a shell because it is stable at high temperatures and has high conductivity compared to other metals.

In an exemplary embodiment of the present application, the thickness of the core portion may be 100 μm to 500 μm, and preferably 200 μm to 300 μm. The thickness of the core portion means the length of the portion indicated by T1 in FIGS. 1 and 2.

When the thickness of the core portion is less than 100 μm, it may be difficult to bond with the air electrode, and when it exceeds 500 μm, there is a problem that pressure is strongly applied to the air electrode.

In one embodiment of the present application, the thickness of the shell portion may be 10 nm to 100 nm, preferably 20 nm to 30 nm. The thickness of the shell portion means the length of the portion indicated by T2 in FIGS. 1 and 2.

When the thickness of the shell portion is less than 10 nm, there is room for silver to diffuse, and when it exceeds 100 nm, there is a problem of limiting the current collecting role of the silver mesh.

In an exemplary embodiment of the present application, the thickness T3 of the cathode current collector means a value obtained by adding the thickness T1 of the core portion and the thickness T2 of each of the shell portions formed above and below the core portion.

A solid oxide fuel cell according to an exemplary embodiment of the present application includes a fuel electrode; An electrolyte layer provided on the anode; An air electrode provided on the electrolyte layer; And the above-described cathode current collector provided on the cathode.

2 is a view showing a solid oxide fuel cell according to an exemplary embodiment of the present application. An anode 200 is provided on one side of the electrolyte layer 300, and an anode 400 is provided on the other side, and an anode current collector 100 is provided on the opposite side of the surface of the anode 200 on which the electrolyte layer 300 is formed. ), A cathode current collector including a core part 500 and a shell part 501 may be provided on the opposite side of the surface of the cathode 400 on which the electrolyte layer 300 is formed. FIG. 2 shows an example of a solid oxide fuel cell, and if necessary, may include only a part of the configuration shown in FIG. 2, or may further include an additional configuration.

In one embodiment of the present application, the thickness of the air electrode may be 20 μm to 100 μm, and preferably 20 μm to 50 μm.

When the thickness of the cathode is less than 20 μm, there is a shortcoming of lack of an active point for reducing oxygen.

In one embodiment of the present application, the cathode may include an inorganic material having oxygen ion conductivity. The inorganic material is yttria stabilized zirconium oxide (zirconia) (YSZ: (Y ₂ O ₃ ) _x (ZrO ₂ ) _1-x , x = 0.05 to 0.15), scandia stabilized zirconium oxide (ScSZ: (Sc ₂ O ₃ ) _x (ZrO ₂ ) _1-x , x = 0.05 ~ 0.15), samarium dope ceria (SDC: (Sm ₂ O ₃ ) _x (CeO ₂ ) _1-x , x = 0.02 ~ 0.4), gadolinium Dope ceria (GDC: (Gd ₂ O ₃ ) _x (CeO ₂ ) _1-x , x = 0.02 to 0.4), Lanthanum strontium manganese oxide (LSM), Lanthanum strontium cobalt ferrite (Lanthanum strontium cobalt ferrite (LSCF), Lanthanum strontium nickel ferrite (LSNF), Lanthanum calcium nickel ferrite (LCNF), Lanthanum strontium cobalt oxide (LSC) gadolinium strontium cobaltium oxide (GSC) strontium cobalt oxide (GSC), Lanthanum strontium ferrite (LSF), Samarium strontium cobalt acid It may include at least one of cargo (Samarium strontium cobalt oxide: SSC), Barium Strontium cobalt ferrite (BSCF), and Lanthanum strontium gallium magnesium oxide (LSGM).

The cathode comprises at least one of Lanthanum strontium cobalt ferrite (LSCF), Lanthanum strontium cobalt oxide (LSC) and Barium Strontium cobalt ferrite (BSCF), electrolyte layer It may further include the same inorganic material as the metal oxide. Specifically, when the electrolyte layer includes a ceria-based metal oxide, the cathode may further include a ceria-based metal oxide. More specifically, when the electrolyte layer includes gadolinium-doped ceria, the cathode may further include gadolinium-doped ceria.

In one embodiment of the present application, the cathode includes lanthanum strontium cobalt oxide.

The manufacturing method of the cathode is not particularly limited, for example, coating and drying and calcining the slurry for the cathode, or coating and drying the slurry for the cathode on a separate release paper to prepare a green sheet for the cathode, one or more An air cathode green sheet can be produced by firing alone or with a neighboring heterogeneous green sheet.

The cathode slurry includes inorganic particles having oxygen ion conductivity, and if necessary, the cathode slurry may further include at least one of a binder resin, a plasticizer, a dispersant, and a solvent. The binder resin, plasticizer, dispersant and solvent are not particularly limited, and conventional materials known in the art may be used.

The thickness of the green sheet for the cathode may be 10 μm or more and 100 μm or less.

Based on the total weight of the slurry for the cathode, the content of the inorganic particles having oxygen ion conductivity is 40% by weight or more and 70% by weight or less, the content of the solvent is 10% by weight or more and 30% by weight or less, and the content of the dispersant is 5% by weight or more and 10% by weight or less, the content of the plasticizer is 0.5% by weight or more and 3% by weight or less, and the binder may be 10% by weight or more and 30% by weight or less.

In one embodiment of the present application, the anode may include an inorganic material having oxygen ion conductivity. The inorganic material is yttria stabilized zirconium oxide (zirconia) (YSZ: (Y ₂ O ₃ ) _x (ZrO ₂ ) _1-x , x = 0.05 to 0.15), scandia stabilized zirconium oxide (ScSZ: (Sc ₂ O ₃ ) _x (ZrO ₂ ) _1-x , x = 0.05 ~ 0.15), samarium dope ceria (SDC: (Sm ₂ O ₃ ) _x (CeO ₂ ) _1-x , x = 0.02 ~ 0.4) and gadolinium Dope ceria (GDC: (Gd ₂ O ₃ ) _x (CeO ₂ ) _1-x , x = 0.02 ~ 0.4).

The thickness of the anode may be 10 μm to 1,000 μm. Specifically, the thickness of the anode may be 100 μm to 800 μm.

The porosity of the anode may be 10% to 50%. Specifically, the porosity of the anode may be 10% to 30%.

The pore diameter of the anode may be 0.1 μm to 10 μm. Specifically, the pore diameter of the anode may be 0.5 μm to 5 μm. More specifically, the pore diameter of the anode may be 0.5 μm to 2 μm.

The manufacturing method of the anode is not particularly limited, for example, coating and drying and firing the slurry for the anode, or coating and drying the anode slurry on a separate release paper to prepare a green sheet for the anode, and at least one anode For the green sheet alone or by firing with a green sheet of an adjacent layer, an anode can be produced.

The thickness of the green sheet for the anode may be 10 μm to 500 μm.

The anode slurry includes inorganic particles having oxygen ion conductivity, and if necessary, the anode slurry may further include at least one of a binder resin, a plasticizer, a dispersant, and a solvent, and the binder resin, a plasticizer, a dispersant, and The solvent is not particularly limited, and conventional materials known in the art may be used.

Based on the total weight of the slurry for the anode, the content of the inorganic particles having oxygen ion conductivity is 10% by weight to 30% by weight, the content of the solvent is 10% by weight to 30% by weight, and the content of the dispersant is 5% by weight % To 10% by weight, the content of the plasticizer is 0.5% to 3% by weight, the content of the binder may be 10% to 30% by weight.

The anode slurry may further include NiO. Based on the total weight of the slurry for the anode, the content of NiO may be 10% to 30% by weight.

The anode may be provided on a separate porous ceramic support or a porous metal support, or may include an anode support and an anode functional layer. At this time, the anode support is a layer containing the same inorganic material as the anode functional layer, but having a higher porosity and relatively thicker thickness than the anode functional layer, and supporting the other layer. The anode functional layer is provided between the anode support and the electrolyte layer. It may be a layer that plays a major role as an actual anode.

When the anode is provided on the porous ceramic support or the porous metal support, the green sheet for the prepared anode can be laminated on the fired porous ceramic support or the porous metal support and fired to produce the anode.

When the anode includes an anode support and an anode functional layer, a green sheet for the prepared anode functional layer can be laminated on the calcined anode support and fired to produce an anode.

When the anode includes an anode support and an anode functional layer, the thickness of the anode support may be 350 μm to 1,000 μm, and the thickness of the anode functional layer may be 5 μm to 50 μm.

The electrolyte layer may include an oxygen ion conductive inorganic material, and is not particularly limited as long as it has oxygen ion conductivity. Specifically, the oxygen ion conductive inorganic material of the electrolyte layer may include a composite metal oxide containing at least one selected from the group consisting of zirconium oxide, cerium oxide, lanthanum oxide, titanium oxide, and bismuth oxide based materials. You can. More specifically, the oxygen ion conductive inorganic material of the electrolyte layer is yttria stabilized zirconium oxide (YSZ: (Y ₂ O ₃ ) _x (ZrO ₂ ) _1-x , x = 0.05 to 0.15), Scandia Stabilized zirconium oxide (ScSZ: (Sc ₂ O ₃ ) x (ZrO ₂ ) _1-x , x = 0.05 ~ 0.15), samarium dope ceria (SDC: (Sm ₂ O ₃ ) x (CeO ₂ ) 1- x, x = 0.02 to 0.4) and gadolinium dope ceria (GDC: (Gd ₂ O ₃ ) x (CeO ₂ ) 1-x, x = 0.02 to 0.4).

The thickness of the electrolyte layer may be 10㎛ to 100㎛. Specifically, the thickness of the electrolyte layer may be 20㎛ to 50㎛.

The manufacturing method of the electrolyte layer is not particularly limited, for example, coating the slurry for the electrolyte layer to dry and calcining it, or coating and drying the slurry for the electrolyte layer on a separate release paper to prepare a green sheet for the electrolyte layer, and the electrolyte The green sheet for a layer can be calcined either alone or together with a green sheet of neighboring layers to produce an electrolyte layer.

The thickness of the green sheet for the electrolyte layer may be 10 μm to 100 μm.

The slurry for the electrolyte layer includes inorganic particles having oxygen ion conductivity, and if necessary, the slurry for the electrolyte layer may further include at least one of a binder resin, a plasticizer, a dispersant, and a solvent, and the binder resin, a plasticizer, a dispersant, and The solvent is not particularly limited, and conventional materials known in the art may be used.

Based on the total weight of the slurry for the electrolyte layer, the content of the inorganic particles having oxygen ion conductivity may be 40% to 70% by weight.

Based on the total weight of the slurry for the electrolyte layer, the content of the solvent is 10% to 30% by weight, the content of the dispersant is 5% to 10% by weight, the content of the plasticizer is 0.5% to 3% by weight, and the binder The content of may be 10% by weight to 30% by weight.

In the present specification, the green sheet refers to a film in the form of a film that can be processed in the next step, not a complete final product. In other words, the green sheet is coated with a coating composition containing inorganic particles and a solvent and dried in a sheet form, and the green sheet refers to a sheet in a semi-dry state that can maintain a sheet form while containing a little solvent.

The shape of the fuel cell is not limited, and may be, for example, coin, flat, cylindrical, horn, button, sheet or stacked.

FIG. 4 schematically shows the electricity generation principle of a solid oxide fuel cell, and the solid oxide fuel cell is composed of an electrolyte layer and an anode and a cathode formed on both sides of the electrolyte layer. do. Referring to FIG. 4, while air is electrochemically reduced at the cathode, oxygen ions are generated and the generated oxygen ions are transferred to the anode through the electrolyte layer. At the anode, fuel such as hydrogen, methanol, butane, etc. is injected, and the fuel is combined with oxygen ions to electrochemically oxidize and release electrons to generate water. The reaction causes electron movement to occur in the external circuit.

A method of manufacturing an anode current collector for a solid oxide fuel cell according to an exemplary embodiment of the present application includes forming a shell portion by coating platinum (Pt) or gold (Au) on a surface of a core portion formed of a metal mesh. . Each configuration of the method for manufacturing a cathode current collector for a solid oxide fuel cell may cite the description of the cathode current collector described above.

In one embodiment of the present application, the coating is performed by a sputtering method, an atomic layer deposition (ALD) method, an electrodeposition method, or a physical vapor deposition (PVD) method It can be, preferably can be performed by sputtering. The sputtering method has the advantage of being capable of uniform coating even in a large area compared to other coating methods, and can be performed at room temperature.

In one embodiment of the present application, the coating thickness may be 10nm to 100nm, preferably 20nm to 30nm. The coating thickness means the deposited thickness of platinum (Pt) or gold (Au).

Claims (9)

A core portion made of a metal mesh; And
An anode current collector for a solid oxide fuel cell having a core-shell structure, which is provided on the surface of the core portion and includes a shell portion including platinum (Pt) or gold (Au). The method according to claim 1,
The metal mesh is a cathode current collector for a solid oxide fuel cell that is a silver mesh (Ag mesh). The method according to claim 1,
The core portion has a thickness of 100 µm to 500 µm, the cathode current collector for a solid oxide fuel cell. The method according to claim 1,
The thickness of the shell portion is 10nm to 100nm cathode current collector for a solid oxide fuel cell. Anode;
An electrolyte layer provided on the anode;
An air electrode provided on the electrolyte layer; And
A solid oxide fuel cell comprising the cathode current collector according to any one of claims 1 to 4 provided on the cathode. A method of manufacturing a cathode current collector for a solid oxide fuel cell, comprising coating a surface of a core made of a metal mesh with platinum (Pt) or gold (Au) to form a shell. The method according to claim 6,
The coating is performed by sputtering (sputtering), atomic layer deposition (atomic layer deposition, ALD), electrodeposition (electrodeposition), or physical vapor deposition (Physical vapor deposition, PVD). The whole manufacturing method. The method according to claim 6,
The metal mesh is a method of manufacturing a cathode current collector for a solid oxide fuel cell that is a silver mesh (Ag mesh). The method according to claim 6,
The coating thickness is 10nm to 100nm method of manufacturing a cathode current collector for a solid oxide fuel cell.

Images