KR102674322B1 - Current collector containing noble metal paste and 2D metal oxide, solid oxide fuel cell using same, and method for manufacturing same - Google Patents

Abstract

A solid oxide fuel cell using a current collector containing precious metal paste and 2D metal oxide and a method for manufacturing the same are provided. The current collector is a solid that not only facilitates the flow of gas in the current collector by adding 2D metal oxide to the precious metal paste, but also increases the lifespan and improves thermal cycle characteristics by providing a gradient in the microstructure of the current collector. An oxide fuel cell is provided.

Description

Current collector containing noble metal paste and 2D metal oxide, solid oxide fuel cell cell using the same, and method for manufacturing the same {Current collector containing noble metal paste and 2D metal oxide, solid oxide fuel cell using same, and method for manufacturing same}

The present invention relates to a solid oxide fuel cell, and more specifically, to a current collector containing precious metal paste and 2D metal oxide, a solid oxide fuel cell using the same, and a method of manufacturing the same.

Recently, with the trend of miniaturization, multi-functionality, weight reduction, and process reduction of electronic products, thin-film and thick-film manufacturing techniques such as micro-patterning, multi-layering, large-area, and low-temperature processes have become the mainstream of electronic product manufacturing processes.

The thick film technique refers to forming a film on a substrate through a screen printing process, etc., and then sintering it at an appropriate temperature. Among these, the thick film technology for electrode manufacturing mainly involves coating a conductive noble metal paste on a substrate, and the coating may be any one of screen printing, spray coating, and brushing.

Precious metal pastes include silver (Ag), platinum (Pt), and gold (Au). In particular, silver (Ag) paste is chemically stable and has excellent conductivity, so it is used as an adhesive or coating agent in the thick film process of electronic components. Since the conductivity of the paste and the adhesion of the coating layer are greatly influenced by the shape of the raw material silver (Ag) powder, technology that can control the shape of the metal powder is required to produce an excellent paste.

Silver (Ag) paste currently used can be applied to the current collector of a solid oxide fuel cell, but when the fuel cell is operated at high temperature, the microstructure of the current collector becomes dense, which not only impedes the flow of gas. In addition, there are problems such as reduced lifespan and thermal cycle characteristics.

Korean Patent Registration No. 10-1335493

The problem to be solved by the present invention is to provide a current collector containing precious metal paste and 2D metal oxide, a solid oxide fuel cell using the same, and a method of manufacturing the same to prevent changes in the microstructure of the current collector within the fuel cell. there is.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

In order to achieve the above technical problem, one aspect of the present invention provides a solid oxide fuel cell. The solid oxide fuel cell cell includes a support, a fuel electrode layer that combines ionized oxygen ions and injected hydrogen to produce water and electrons, and a support, stacked on top of the support, and a fuel electrode layer that produces water and electrons, and is stacked on top of the fuel electrode layer, where hydrogen and air are mixed. A solid electrolyte layer that blocks oxygen ions and passes oxygen ions at the same time, laminated on top of the solid electrolyte layer, an air electrode layer that produces oxygen ions by reducing injected air, and laminated on top of the air cathode layer, precious metal paste and 2D metal oxide A current collector comprising a; and the support may be either a metal support or a ceramic support.

A protective layer may be included between the solid electrolyte layer and the air cathode layer.

The protective layer may include Ce _1-y Ln _y O _2-β (Ln=Gd, Sm, Nd or La, y=0.1∼0.3, β=0∼0.2).

The metal support may be any one of Ni metal, Ni-Fe alloy, and STS (Stainless Steel).

The ceramic support may be any one of NiO and rare earth-doped zirconia composite, NiO and rare earth-doped ceria composite, rare earth-doped zirconia composite and rare earth-doped ceria.

The anode layer may be either a NiO and rare earth-doped zirconia composite or a NiO and rare earth-doped ceria composite.

The anode layer may further include any one or more of perovskite-based oxide and CeO ₂ .

It is inserted between the support and the anode layer and may include a contact layer that passes gas and electricity and acts as a buffer in terms of microstructure.

The contact layer may be a mixture of components of the metal support and components of the anode layer.

The composition of the air cathode layer may include perovskite-based oxide.

The composition of the air cathode layer may further include at least one of a sintered powder mixture of rare earth-doped ceria or a pore former.

The solid electrolyte layer may be any one of rare earth-doped zirconia-based oxide, rare earth-doped ceria-based oxide, and perovskite-based oxide.

The perovskite-based oxide may be La _1-x A _x Ga _1-y B _y O ₃ (A=Sr, Ba; B=Mg, Ca).

Another aspect of the present invention provides a method for manufacturing a solid oxide fuel cell. The manufacturing method of the solid oxide fuel cell includes a first step of preparing a support, a second step of laminating an anode layer on top of the support, a third step of laminating the solid electrolyte layer on top of the anode layer, A fourth step of co-sintering the composite laminated in steps 1 to 4, a fifth step of laminating an air cathode layer on top of the solid electrolyte layer in the composite, and a sixth step of laminating a current collector on top of the air cathode layer. may include.

After the first step, a contact layer may be laminated on the support before lamination of the anode layer.

After the fourth step, a protective layer may be laminated on the solid electrolyte layer of the co-sintered composite before lamination of the air cathode layer.

In the sixth step, the current collector is formed on the upper part of the air electrode layer by laminating it using a slurry using a thick film coating method,

The thick film coating method may be any one of screen printing, spray coating, and brushing.

The slurry may include noble metal paste and 2D metal oxide.

The noble metal paste and the 2D metal oxide may be mixed at a weight ratio of 1:0.01 to 1:0.1.

The noble metal paste may be any one of silver (Ag) paste, platinum (Pt) paste, and gold (Au) paste.

The 2D metal oxide may be any one of RuO ₂ , IrO ₂ , PbO ₂ , PtO ₂ , CoO ₂ and MoO ₂ .

The thickness of the 2D metal oxide may be 1 nm to 100 nm.

As described above, according to the present invention, a 2D metal oxide is added to a current collector containing a precious metal paste to prevent changes in the microstructure of the current collector and to facilitate the flow of gas, thereby increasing the lifespan and thermal cycle characteristics of the solid. An oxide fuel cell and its manufacturing method can be provided.

1 is a schematic diagram showing the structure of a solid oxide fuel cell according to an embodiment of the present invention.
Figure 2 is a flow chart showing a method of manufacturing a solid oxide fuel cell according to an embodiment of the present invention.
Figure 3 is a flowchart schematically showing the synthesis of 2D metal oxide nanosheets.
Figure 4 is an AFM image and FE-SEM image of 2D metal oxides obtained through solid-phase synthesis and chemical exfoliation.
Figure 5 shows changes in the microstructure of the current collector after heat treatment for a certain period of time in a solid oxide fuel cell to which a current collector containing a precious metal paste to which 2D metal oxide was added was applied according to an embodiment of the present invention. It's a photo.

Hereinafter, in order to explain the present invention in more detail, preferred embodiments according to the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms.

The terminology used herein is only intended to refer to specific embodiments and is not intended to limit the invention. As used herein, singular forms include plural forms unless phrases clearly indicate the contrary. As used in the specification, the meaning of “comprising” is to specify a specific characteristic, area, integer, step, operation, element and/or component, and to specify another specific property, area, integer, step, operation, element, component and/or group. It does not exclude the existence or addition of .

Although not defined differently, all terms including technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted as having meanings consistent with related technical literature and currently disclosed content, and are not interpreted in ideal or very formal meanings unless defined.

Additionally, in the drawings herein, the thicknesses of layers and regions are exaggerated for clarity. Like reference numerals refer to like elements throughout the specification.

Hereinafter, embodiments of the present invention will be described in detail. These examples are merely for illustrating the present invention, and the present invention is not limited thereto.

1 is a schematic diagram showing the structure of a solid oxide fuel cell according to an embodiment of the present invention. Referring to FIG. 1, the support-type solid oxide fuel cell 10 has an anode layer 12 stacked on top of a support 11, a solid electrolyte layer 13 is stacked on top of the anode layer, and the top of the solid electrolyte layer An air electrode layer 14 may be stacked on the air electrode layer, and a current collector 15 may be stacked on top of the air electrode layer.

The support 11 may be either a metal support or a ceramic support. The fuel cell including the metal support may be coated with an anode layer 12, a solid electrolyte layer 13, and an air electrode layer 14 in the form of a thick film on the top of the metal support, and between the metal support and the anode layer 12. A contact layer (not shown) may be additionally inserted. Meanwhile, a fuel cell including a ceramic support may be one in which an anode layer 12, a solid electrolyte layer 13, and an air electrode 14 are coated in the form of a thick film on the ceramic support.

The metal support has a small decrease in electrical conductivity due to high-temperature oxidation, has redox stability, and has a thermal expansion coefficient of 5 to 20 (ppm/℃), specifically 10 to 15 (ppm/℃). desirable. Materials for metal supports having such characteristics include any one of Ni, Ni-Fe alloy, and stainless steel (STS), and the stainless steel may in particular be ferritic stainless steel, product name STS434L. and the product name Crofer22H from Germany's Tyssenkrupp.

The ceramic support may be an anode support or an electrolyte support, and the anode support may be NiO and rare earth-doped zirconia (Zr _1-x D _x O ₂ (D= Y, Sc, La, Ce, Pr, Nd, Pm, Sm , Eu, Gd, Tb, Dy, Ho _, Er _, Tm, Yb, Lu _; La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; Or it may be rare earth-doped ceria.

According to one embodiment of the present invention, an anode layer 12 may be laminated on the support 11. In the anode layer 12, hydrogen, which is a fuel injected from the outside, and ionized oxide ions moving from the solid electrolyte layer 13 combine to generate water and electrons. The ceramic precursor powder, which is a component of the anode layer 12, may include a NiO and rare earth-doped zirconia composite or a NiO and rare earth-doped ceria composite. Additionally, the composite may further include any one or more of perovskite-based oxide and CeO ₂ . At this time, the perovskite is a structured compound in the form of ABO ₃ , where the A site is occupied by one or more of the elements lanthanum (La), Sr, Ba, Sm, and Pr, and the B site is occupied by manganese. It may be composed of a mixture of some or all of the following elements: (Mn), Ti, Cr, V, Ni, Co, Fe, Al, Nb, Mo Mg, and Ca, specifically La _1-x A _x Ga _1-y It may include B _y O ₃ (A=Sr, Ba; B=Mg, Ca).

Meanwhile, when a metal support is used as the support 11, a contact layer (not shown) may be additionally inserted, and the contact layer (not shown) passes gas and electricity while providing a buffer in terms of microstructure. ) function. Specifically, the metal support and the anode layer 12 have a large difference in density and particle size, which may cause a difference in gas flow and a large strain between layers. At this time, by positioning the contact layer (not shown) between the metal support and the anode layer 12, not only does it serve as a buffer to alleviate the microstructural difference, but the contact layer (not shown) serves as a buffer between the metal support and the anode layer 12. It can play a role in suppressing interlayer delamination due to differences in thermal expansion coefficients between layers 12.

Additionally, the composition of the contact layer (not shown) may be a mixture of components of the metal support and components of the anode layer 12. Specifically, the component of the contact layer (not shown) may be a mixture of NiO ₂ or Crofer22H, which is a component of the metal support, and rare earth-doped zirconia, which is a component of the anode layer 12. At this time, the composition ratio of the components of the metal support and the components of the anode layer 12 in the contact layer (not shown) may be 9:1 to 6:4, and in detail, 8:2 to 6:4. , more specifically, it may be 7:3 to 6:4.

According to one embodiment of the present invention, a solid electrolyte layer 13 may be stacked on top of the anode layer 12. The solid electrolyte layer 13 prevents hydrogen and air from mixing and allows only oxygen ions to pass through. Additionally, the component of the solid electrolyte layer 13 may be rare earth-doped zirconia, rare earth-doped ceria, or perovskite-based oxide.

Meanwhile, an air cathode layer 14 may be laminated on the solid electrolyte layer 13. The air cathode layer 14 can produce oxygen ions by reducing air supplied from the outside. Additionally, the components of the air cathode layer 14 may include a conductor containing perovskite-based oxide alone or a pore-forming agent such as a sintered powder mixture of rare earth-doped ceria and graphite powder.

Specifically, the perovskite-based oxide contained in the cathode layer 14 is La _1-x Sr _x Co _y Fe _1-y O _3-δ (where x = 0.2 to 0.5, y = 0.2 to 1, and δ =0∼0.3). In particular, the conductor mixed with perovskite oxide is one or more La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O _3-δ , GdCoO _3-δ and Re _x Sr _1-x CoO _3-δ (Re=La, Sm , Pr, 0.5<x<0.8 and δ=0∼0.3). Using these compounds can be useful because they have higher ionic conductivity than most perovskite-based oxides. In some cases the mixture may comprise 20 to 50% by weight of rare earth-doped ceria, in some cases in the 30 to 45% by weight range, in some cases in the 35 to 45% by weight range, or approximately 40% by weight of rare earth-doped ceria as previously defined. You can. This helps to improve the compatibility between the solid electrolyte layer 13 and the cathode layer 14 both in terms of chemistry and the aforementioned thermal expansion, and since these ceria have a high charge transport rate, their inclusion is beneficial to the solid electrolyte layer. A good charge transport rate between (13) and the air cathode layer (14) can be ensured.

More specifically, the air cathode layer 14 may include a perovskite-based oxide such as LSM (La _0.8 Sr _0.2 MnO ₃ ) and ScSZ (Sc-doped ZrO ₂ ). Meanwhile, the LSM is used as a material for an air electrode or a solid electrolyte layer 13 made of rare earth-doped ceria or perovskite-based oxide La _1-x A _x Ga _1-y B _y O ₃ (A=Sr, Ba; When B=Mg, Ca;

Meanwhile, high-performance anode materials such as LSCF ((La _0.6 Sr _0.4 )(Co _0.2 Fe _0.8 )O ₃ ) and BSCF (Br _0.5 Sr _0.5 Co _0.8 Fe _0.2 O _3-δ ) are used as the air cathode layer 14 instead of LSM. Alternatively, when rare earth-doped zirconia is used as the solid electrolyte layer 13, an additional protective layer (not shown) may need to be inserted between the solid electrolyte layer 13 and the air cathode layer 14.

The protective layer (not shown) is located between the solid electrolyte layer 13 and the cathode layer 14 to prevent diffusion of the composition between the layers, thereby suppressing the generation of impurities, and Ce _1-y It may be composed of Ln _y O _2-β (Ln=Gd, Sm, Nd or La, y=0.1∼0.3, β=0∼0.2). Here, the protective layer (not shown) is a solid electrolyte layer (13) made of Ce _1-x Ln _x O _2-δ (Ln=La, Gd, Sm, Nd or Y, x=0.1∼0.3, δ=0∼0.2) ), the y may be greater than x, and the β may be greater than δ.

Additionally, according to one embodiment of the present invention, a current collector 15 may be stacked on top of the air cathode layer 14. The current collector 15 collects current from the battery in the stack, and may be a 2D metal oxide introduced into a conductive noble metal paste. When the current collector 15 is formed using only the precious metal paste, the microstructure of the current collector 15 may become dense when the fuel cell is operated at a high temperature, thereby impeding the flow of gas. Therefore, by adding 2D metal oxide to the noble metal paste, densification of the microstructure of the current collector 15 can be reduced or prevented.

At this time, in the current collector, the noble metal paste and the 2D metal oxide are mixed at a weight ratio of 1:0.01 to 1:1, preferably 1:0.01 to 1:0.5, more preferably 1:0.01 to 1:0.1. It may be characterized as being made, but is not limited thereto.

The precious metal paste is composed of a conductive filler, glass frit, which is glass powder, and a vehicle, which is a solvent. The conductive filler is mostly a metal powder and forms a conductive path for the electrode, and the glass frit is melted during heat treatment. It can not only induce densification of the conductive filler but also serve to fix the conductive filler on the substrate. Additionally, the vehicle, which is the solvent, is an organic solvent that can disperse the conductive filler and the frit to provide printing workability.

The metal powder used as the conductive filler may be a noble metal, and the noble metals may include silver (Ag), gold (Au), and platinum (Pt). In particular, the silver (Ag) powder has good conductivity and is chemically stable, so it can be used as the current collector 15 of a solid oxide fuel cell.

Glass frit, one of the main components of precious metal paste, is inexpensive and requires dielectric properties, insulation, and chemical resistance, and low melting point may be essential to suppress reaction with the device due to high heat during bonding. In addition, matching thermal expansion coefficients between materials is required to prevent thermal stress from occurring with the adhesive, and airtightness and stability with the adhesive may also be required.

The glass frit may be, for example, silicon oxide with additives added. The additives include lithium (Li), nickel (Ni), cobalt (Co), boron (B), potassium (K), aluminum (Al), titanium (Ti), manganese (Mn), copper (Cu), and zirconium ( It may include at least one of Zr), phosphorus (P), zinc (Zn), bismuth (Bi), lead (Pb), and sodium (Na). The additives are not limited to the elements listed above.

Meanwhile, the 2D metal oxide may be a nanosheet with a two-dimensional planar structure having a hexagonal structure. The 2D metal oxide may have an average thickness ranging from, for example, 1 nm to 100 nm, specifically 1 nm to 50 nm, and more specifically, 1 nm to 30 nm. In addition, the 2D metal oxide may be a single layer or multiple layers of nanosheets made of metal oxide stacked from several to tens of layers, and may specifically be a stack of 1 to 30 nanosheet layers, and more specifically, 1 to 30 nanosheet layers. It may be a stack of up to 10 nanosheet layers.

The 2D metal oxide may be RuO ₂ , IrO ₂ , PdO ₂ , PtO ₂ , CoO ₂ or MoO ₂ , but is not limited thereto. In particular, the 2D metal oxide may be RuO ₂ , CoO ₂ or MoO ₂ .

Figure 2 is a flow chart showing a method of manufacturing a solid oxide fuel cell according to an embodiment of the present invention. In the method of manufacturing the solid oxide fuel cell, a contact layer (not shown) is selectively formed on the support 11, an anode layer 12 is formed on the anode layer 12, and a solid electrolyte layer ( 13) is formed, a protective layer (not shown) is selectively formed on the solid electrolyte layer 13, an air electrode layer 14 is formed on the top, and a current collector 15 is sequentially formed on the top. there is.

Referring to FIG. 2, in order to manufacture the solid oxide fuel cell, a support 11 is first manufactured (S101). Manufacturing of the support 11 may involve producing a pellet using a mixed powder containing metal powder and/or metal oxide powder, followed by pre-sintering at 800 to 1000°C. . At this time, the metal used in the mixed powder is one or more metals selected from the group consisting of nickel (Ni), iron (Fe), chromium (Cr), and stainless steel (STS), or an alloy of two or more metals, NiO It may be a rare earth-doped zirconia composite, a rare earth-doped ceria composite with NiO, a rare earth-doped zirconia composite, or a rare earth-doped ceria.

Afterwards, a slurry was prepared to form the anode layer 12 on one side of the support 11, followed by drop-coating and drying in an oven (S102). The slurry may include a ceramic precursor powder of NiO and a rare earth-doped zirconia composite or a composite of NiO and rare earth-doped ceria, and the composite may further include any one or more of perovskite-based oxide and CeO ₂ . .

According to one embodiment of the present invention, the step of forming a contact layer (not shown) between the support 11 and the anode layer 12 may be further included, and the contact layer (not shown) is formed by producing a slurry. It is manufactured by drop coating and drying in an oven, and can be stacked and placed between the support 11 and the anode layer 12. At this time, the slurry used for the contact layer (not shown) may contain metal oxide powder, which is a component of the support 11, and components of the anode layer 12.

The solid electrolyte layer 13 is also manufactured by preparing a slurry on the top of the anode layer 12, followed by drop coating and drying in an oven (S103), and the slurry used in the solid electrolyte layer 13 is rare earth-doped. It may include zirconia powder, rare earth-doped ceria powder, or perovskite-based oxide powder. A laminate composed of a support 11, a contact layer (not shown), an anode layer 12, and a solid electrolyte layer 13 is manufactured through drop coating using the slurry.

Afterwards, the laminate goes through a step of co-sintering (S104), and the co-sintering process may be heat treatment in the range of 1300°C to 1400°C in a sintering furnace in an argon atmosphere. Through the sintering step, the support 11, the contact layer (not shown), the anode layer 12, and the solid electrolyte layer 13 can be joined by co-sintering in a reducing atmosphere.

An air cathode layer 14 may be formed on the solid electrolyte layer 13 (S105). The formation of the air cathode layer 14 is performed by a screen-printing process after producing a slurry, and the slurry used for the air cathode layer 14 is a conductor containing perovskite-based oxide alone or , sintered powder mixture of rare earth-doped ceria and pore formers such as graphite powder. At this time, the step of forming a protective layer (not shown) between the solid electrolyte layer 13 and the air cathode layer 14 may be further included, and the protective layer (not shown) may also be applied to the screen after producing the slurry. It may be manufactured through a screen-printing process and placed in a stack between the solid electrolyte layer 13 and the air cathode layer 14.

Finally, the current collector 15 completes the solid oxide fuel cell by laminating the slurry prepared using the thick film coating method on the upper part of the air electrode layer 14 (S106). The slurry used to manufacture the current collector 15 may be a mixture of noble metal paste and 2D metal oxide, and the thick film coating method may be any one of screen printing, spray coating, and brushing. In addition, the 2D metal oxide _{is A} <x ≤ 0.3) can be obtained by chemical exfoliation. At this time, the chemical peeling method may be a process of adding acid (for example, treatment using 1 M HCl), but is not limited thereto.

Below, a preferred experimental example is presented to aid understanding of the present invention. However, the following experimental examples are only intended to aid understanding of the present invention, and the present invention is not limited by the following experimental examples.

<Manufacturing examples>

Preparation Example 1: Preparation of a solid oxide fuel cell to which a current collector containing precious metal paste and 2D metal oxide is applied.

Preparation of metal support

NiO ₂ [Kceracell, 99.9%, (d50) ∼ 0.7 ㎛] and Fe ₂ O ₃ (LTS Research laboratories, 99.9%) were mixed at a volume ratio of 5:5 and a ball mill process was performed. Afterwards, the powder obtained by drying was manufactured into pellets of 1 g each (approximately 1 mm thick) using a mold with a diameter of 20 mm (pressing pressure: 50 MPa). The produced pellets were pre-sintered at 900°C for 2 hours.

Preparation of contacting layer

To manufacture the contact layer, slurry production was first performed. The slurry contains NiO ₂ (Kceracell, 99.9%) as a metal support component and 8YSZ ((Y ₂ O ₃ ) _0.08 (ZrO ₂ ) _0.92 , Kceracell, 99.9%, (d50) ∼ 0.22 ㎛) or ScSZ-6 as an anode component. It was manufactured by adding corn starch to raw material powder mixed with (6 mol% Sc ₂ O ₃ ) in a volume ratio of 7:3 and then ball milling. The prepared slurry was drop coated on the pre-sintered pellets and then dried in an oven (30° C.).

Manufacturing of anode layer composed of Ni-ScSZ (Ce, Gd)

To manufacture the anode layer, slurry production was first performed. The slurry is a mixture of raw material powder NiO ₂ (Kceracell, 99.9%), 10Sc _0.5 Ce _0.5 GdSZ((Sc ₂ O ₃ ) _0.1 (CeO ₂ ) _0.005 (Gd ₂ O ₃ ) _0.005 (ZrO ₂ ) mixed at a volume ratio of 5.5:4.5. _0.89 , Kceracell, 99.9%, (d50) ∼ 0.15 ㎛) and corn starch were mixed and prepared through ball milling (150 rpm, 24 hours). 230 ㎕ of the prepared slurry was drop coated on the pellet formed up to the contact layer and dried in an oven (30° C.).

Manufacturing of a solid electrolyte layer composed of ScSZ (Ce, Gd)

To manufacture the solid electrolyte layer, slurry production was first performed. The slurry is a mixture of 10Sc _0.5 Ce _0.5 GdSZ ((Sc ₂ O ₃ ) _0.1 (CeO ₂ ) _0.005 (Gd ₂ O ₃ ) _0.005 (ZrO ₂ ) _0.89 , Kceracell, 99.9%, (d50) ∼ 0.15 ㎛) and ethanol. It was manufactured through ball milling (150 rpm, 24 hours). 120 ㎕ of the slurry prepared above was drop coated on the pellet coated up to the anode layer and dried in an oven (30° C.). After drying, co-sintering was performed at 1350°C.

Fabrication of a cathode layer containing LSM and ScSZ (Ce, Gd)

In the case of the air cathode layer, it was formed through a screen printing technique on a dense solid electrolyte layer. _Air cathode powders _, LSM ( _{( La} For screen printing, a 30 ㎛ thick mesh substrate and the air electrode mixture powder were used to form a circle with a diameter of 7.5 mm in the center of the solid electrolyte layer. Afterwards, heat treatment was performed in air at 1200°C for 2 hours.

Manufacturing of a current collector containing silver (Ag) paste with 2D metal oxide and a cell containing the same

A cell was manufactured by forming a current collector using a pre-prepared slurry on the air electrode layer using a screen printing technique. The slurry was prepared by adding 5 wt% of commercially available silver (Ag) paste (CSP-1381, Changsung Nanotech, high-temperature silver paste) and self-produced 2D RuO ₂ to the silver (Ag) paste, and mechanically stirring for 20 minutes. It was used by mixing.

2D metal oxide manufacturing example: 2D RuO ₂ Synthesis of nanosheets

Figure 3 is a flowchart schematically showing the synthesis of 2D metal oxide nanosheets. As an example of a 2D metal oxide nanosheet, to prepare a 2D RuO ₂ nanosheet, first, K ₂ CO ₃ (99.5 %, Samchun Chemical) and RuO ₂ (99.9 %, Avention) powder were mixed using a mortar and pestle. Next, the mixture was placed in an alumina crucible and subjected to solid phase synthesis at 1123 K for 10 hours. Through the above synthesis, the K _0.2 RuO ₂ layered structure mother phase was synthesized, which can appear in the form shown in Figure 3(a).

The K _0.2 RuO ₂ layered structure matrix was acid treated using hydrochloric acid (HCl) at a concentration of 1 M at room temperature. _{Bulk hydrated ruthenium oxide} ^{( RuO} _​ It may appear in the same form as (b).

It was then dried in a vacuum oven at 298 K. Nanosheets were obtained by chemically exfoliating the dried ruthenium oxide with an aqueous tetrabutylammonium hydroxide (TBAOH) solution, and the nanosheets are shown in FIG. 3(c).

Figure 4 is an AFM image and FE-SEM image of 2D metal oxides obtained through solid-phase synthesis and chemical exfoliation. Figure 4(a) is an AFM image of a 2D RuO ₂ nanosheet, Figure 4(b-1) is an AFM image of a 2D CoO ₂ nanosheet single layer, and Figure 4(b-2) is a 2D CoO ₂ nanosheet. This is an AFM image of two or more stacked multiple layers, and Figure 4(c) is an FE-SEM image of a 2D MoO ₂ nanosheet.

Referring to FIG. 4, it can be seen that all images of 2D metal oxide nanosheets have a thickness of 1 nm to 100 nm and clearly have a 2D shape. In particular, referring to FIGS. 4(b-1) and 4(b-2), the thickness (T) is 5 nm to 30 nm, and the size (lateral size) of one particle layer represented by ℓ is 400 ㎛ to 400 ㎛. It was measured at 800 ㎛, and when observed with the naked eye, it can be seen that it is all 2D material.

Preparation Example 2: Preparation of a solid oxide fuel cell to which a current collector containing precious metal paste and 2D metal oxide is applied.

When preparing the slurry used to manufacture the current collector, a solid oxide fuel cell was manufactured as in Preparation Example 1, except that 10 wt% of 2D RuO ₂ was added to the silver (Ag) paste.

Comparative Example 1: Manufacturing of a solid oxide fuel cell using a current collector containing precious metal paste and 2D metal oxide

When preparing the slurry used to manufacture the current collector, a solid oxide fuel cell was manufactured as in Preparation Example 1, except that the 2D RuO ₂ was not added to the silver (Ag) paste.

<Evaluation examples>

density experiment

The densities of the current collectors according to Preparation Example 1, Preparation Example 2, and Comparative Example 1 in air at 800° C. were measured over a certain period of time. The Image J program was used to measure the density of the current collector. Through the ImageJ program, first, the SEM image of each current collector was scanned. At this time, the sample appeared bright and the pores appeared dark, and the density was measured through this ratio. Table 1 below summarizes the change in density over time of the current collectors prepared in Preparation Example 1, Preparation Example 2, and Comparative Example 1 after a certain period of time in air at 800°C.

division density(%) 10 minutes 1 day 3 days 5 days 7 days Manufacturing Example 1 83 84 86 87 89 Production example 2 83 85 87 87 89 Comparative Example 1 89 92 93 95 97

Referring to Table 1, in the case of Preparation Example 1 and Preparation Example 2 in which 2D RuO ₂ was added when manufacturing the current collector, the density was measured at 89% even after 7 days. In particular, in the case of Preparation Example 1 in which 5 wt% of 2D RuO ₂ was added to the silver (Ag) paste, it can be seen that the density change was lower from 1 to 3 days compared to Preparation Example 2 in which 10 wt% was added. .

On the other hand, in Comparative Example 1 using only the silver (Ag) paste without adding the 2D RuO ₂ when manufacturing the current collector, the density rapidly increased to 89% after 10 minutes and was 97% after 7 days. . Therefore, it can be seen that when the 2D RuO ₂ is added when manufacturing a current collector, sintering occurs less and porosity can also be secured.

Microstructure evaluation

Figure 5 shows changes in the microstructure of the current collector after heat treatment for a certain period of time in a solid oxide fuel cell to which a current collector containing a precious metal paste to which 2D metal oxide was added was applied according to an embodiment of the present invention. It's a photo. In order to evaluate the change in microstructure of the current collector, a solid oxide fuel cell was manufactured and then heat treated for 10 minutes, 1 day, 3 days, 5 days, and 7 days. Preparation Example 1, Preparation Example 2, and Comparison The results according to Example 1 are shown in Figures 5(a), 5(b), and 5(c), respectively.

Referring to FIG. 5, in the case of Preparation Example 1 (FIG. 5(a)) and Preparation Example 2 (FIG. 5(b)) in which 2D RuO ₂ was added during the manufacture of the current collector, the display appears dark even after a certain period of time. Pores were observed. In particular, in the case of Preparation Example 1 in which 5 wt% of 2D RuO ₂ was added to the silver (Ag) paste, the decrease in porosity was further suppressed and sintering occurred less.

On the other hand, in the case of Comparative Example 1 (FIG. 5(c)), in which the current collector was manufactured only with silver (Ag) paste without adding the 2D RuO ₂ , it was difficult to observe pores after 1 day, and almost no pores were present after 7 days. Since it is not observed, it can be seen that sintering occurs quickly. Therefore, when manufacturing a current collector, a certain amount of 2D RuO ₂ is added to the silver (Ag) paste to reduce changes in the microstructure of the current collector during high-temperature operation of the solid oxide fuel cell cell, thereby securing porosity and facilitating the flow of gas. It can be done smoothly.

Above, the present invention has been described in detail with preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications and changes can be made by those skilled in the art within the technical spirit and scope of the present invention. Change is possible.

10: solid oxide fuel cell 13: solid electrolyte layer
11: support 14: air electrode layer
12: anode layer 15: current collector

Claims (22)

support;
An anode layer laminated on top of the support and producing water and electrons by combining ionized oxygen ions and injected hydrogen;
A solid electrolyte layer laminated on top of the anode layer, which prevents hydrogen and air from mixing and at the same time allows oxygen ions to pass through;
An air electrode layer laminated on top of the solid electrolyte layer and producing oxygen ions by reducing injected air; And
It is laminated on the upper part of the air electrode layer and includes a current collector containing noble metal paste and 2D metal oxide,
The 2D metal oxide is a nanosheet with a hexagonal two-dimensional planar structure and is RuO ₂ , CoO ₂ or MoO ₂ ,
A solid oxide fuel cell cell in which the support is a metal support or a ceramic support. According to paragraph 1,
A solid oxide fuel cell including a protective layer between the solid electrolyte layer and the air electrode layer. According to paragraph 2,
The protective layer is a solid oxide fuel cell containing Ce _1-y Ln _y O _2-β (Ln=Gd, Sm, Nd or La, y=0.1∼0.3, β=0∼0.2). According to paragraph 1,
A solid oxide fuel cell in which the metal support is one of Ni metal, Ni-Fe alloy, and STS (Stainless Steel). According to paragraph 1,
The ceramic support is a solid oxide fuel cell that is any one of NiO and rare earth-doped zirconia composite, NiO and rare earth-doped ceria composite, rare earth-doped zirconia composite and rare earth-doped ceria. According to paragraph 1,
A solid oxide fuel cell in which the anode layer is a composite of NiO and rare earth-doped zirconia or a composite of NiO and rare earth-doped ceria. According to clause 6,
The anode layer is a solid oxide fuel cell further comprising at least one of perovskite-based oxide and CeO ₂ . According to paragraph 1,
A solid oxide fuel cell cell including a contact layer that is inserted between the support and the anode layer and acts as a buffer in terms of microstructure while allowing gas and electricity to pass through. According to clause 8,
The contact layer is a solid oxide fuel cell in which the components of the metal support and the components of the anode layer are mixed. According to paragraph 1,
A solid oxide fuel cell cell including perovskite-based oxide as a composition of the air electrode layer. According to clause 10,
A solid oxide fuel cell cell further comprising a sintered powder mixture of rare earth-doped ceria or a pore former in the composition of the cathode layer. According to paragraph 1,
A solid oxide fuel cell in which the solid electrolyte layer is any one of rare earth-doped zirconia-based oxide, rare-earth-doped ceria-based oxide, and perovskite-based oxide. delete The first step of preparing a support;
A second step of laminating an anode layer on top of the support;
A third step of laminating a solid electrolyte layer on top of the anode layer;
A fourth step of co-sintering the composite laminated in the first to third steps;
A fifth step of laminating an air cathode layer on top of the solid electrolyte layer in the composite; and
A sixth step of laminating a current collector on top of the air electrode layer;
Including,
In the sixth step, the current collector is formed on the upper part of the air electrode layer by laminating it using a slurry using a thick film coating method,
The thick film coating method is any one of screen printing, spray coating, and brushing,
The slurry is a method of manufacturing a solid oxide fuel cell cell containing a precious metal paste and a 2D metal oxide. According to clause 14,
After the first step, the method of manufacturing a solid oxide fuel cell further includes laminating a contact layer on top of the support before laminating the anode layer. According to clause 14,
After the fourth step, the method of manufacturing a solid oxide fuel cell further includes the step of laminating a protective layer on top of the solid electrolyte layer of the co-sintered composite before laminating the cathode layer. delete delete According to clause 14,
A method of manufacturing a solid oxide fuel cell, characterized in that the noble metal paste and the 2D metal oxide are mixed at a weight ratio of 1:0.01 to 1:0.1. According to clause 14,
A method of manufacturing a solid oxide fuel cell cell in which the precious metal paste is any one of silver (Ag) paste, platinum (Pt) paste, and gold (Au) paste. According to clause 14,
The 2D metal oxide is hexagonal and is any one of RuO ₂ , CoO ₂ and MoO ₂ . A method of manufacturing a solid oxide fuel cell. According to clause 21,
A method of manufacturing a solid oxide fuel cell cell wherein the 2D metal oxide has a thickness of 1 nm to 100 nm.