KR20090016911A - Method for electrode manufacturing of solid oxide fuel cell using aerosol nano combustion spray technique - Google Patents

Abstract

A method for manufacturing an electrode of a solid oxide fuel cell is provided to facilitate the manufacture of a unit electrode of a fuel battery by forming an ultra thin electrode with a direct surface coating technology. A method for manufacturing an electrode of a solid oxide fuel cell by using a nano spray combustion device comprises a step for manufacturing a precursor of a cathode, an anode and electrolyte; a step for sintering an anode substrate as an anode support layer by using an anode precursor; a step for molding an electrolyte layer by coating the precursor of the electrolyte layer on an anode substrate with an aerosol nano spray technology and heat-treating it; and a step for molding a cathode layer by coating a cathode precursor on the electrolyte layer with an aerosol nano spray technology and heat-treating it.

Description

Electrode Fabrication Method of Solid Oxide Fuel Cell Using Nanospray Combustion Device {METHOD FOR ELECTRODE MANUFACTURING OF SOLID OXIDE FUEL CELL USING AEROSOL NANO COMBUSTION SPRAY TECHNIQUE}

According to the present invention, the electrode or electrolyte precursor is coated on a substrate by an aerosol nano spray method, and then heat-treatment is performed so that each electrode or electrolyte layer can be manufactured by coating and heat-treatment without sintering individually. The present invention relates to an electrode manufacturing method of a solid oxide fuel cell using a nanospray combustion device.

A general industrial solid oxide fuel cell is composed of unit electrodes stacked in the order of cathode-electrolyte-anode. Such a fuel cell is formed of a sintered body, regardless of the composition of each constituent layer, and is then formed as a unit electrode by connecting the layers, and again, after the final sintering process by joining each layer, the entire unit cell Is completed. If necessary, the unit electrodes are stacked in a stack to produce a required power.

Specifically, the manufacturing process of the fuel cell of the prior art will be described in detail. The solid oxide fuel cell is composed of a cathode-electrolyte-anode structure, whether planar or cylindrical. The sintering may be performed using an oxide powder having a desired composition, or after initial molding using a screen printing thick film printing technique, followed by sintering again to obtain a final molding density, thereby exhibiting the performance of a fuel cell.

Therefore, technically, large-capacity fuel cells due to differences in coefficients of thermal expansion according to compositional differences between layers of sintered bodies, limitations in not manufacturing a large-area electrode, limitations in stacking a large number of stacks, etc. Manufacturing becomes difficult. In addition, as the size increases, the planarization of each sintered compact layer becomes difficult.

Due to these problems, the electrode area of currently available developments is limited to a maximum of 100 x 100 mm ² or 200 x 200 mm ² . If you continue to commercialize with these problems, the industry will lose competitiveness.

Accordingly, the present invention is to solve the above-mentioned problems of the prior art, in the case of a cathode-supported flat fuel cell for the manufacture of a high-performance solid oxide fuel cell in a simpler and more competitive way is followed on the cathode substrate The electrolytic and anode layers can be formed by nano spray coating technology, and in the case of electrolyte-supported flat fuel cells, the cathode and anode layers are coated on both sides of the electrolyte by coating technology. It is an object of the present invention to provide a method for producing an electrode of a solid oxide fuel cell using a nanospray combustion apparatus capable of forming an electrode.

Electrode manufacturing method of a solid oxide fuel cell using a nanospray combustion apparatus of the present invention for achieving the above object comprises a precursor manufacturing process for producing a precursor of the anode, cathode and electrolyte layer; A negative electrode support layer generating step of sintering a negative electrode substrate to be a negative electrode support layer using the negative precursor; Forming an electrolyte layer by coating a precursor of the electrolyte layer on the anode substrate by an aerosol nano spray method and then performing heat treatment; Anode layer forming process of forming a cathode layer by coating the cathode precursor by the aerosol nano spray method on the electrolyte layer and then performing a heat treatment.

Electrode manufacturing method of a solid oxide fuel cell using a nanospray combustion apparatus of the present invention for achieving the above object comprises a precursor manufacturing process for manufacturing a positive electrode, a negative electrode and an electrolyte precursor; An electrolyte support layer generating step of sintering an electrolyte substrate which becomes an electrolyte support layer using the electrolyte precursor; One surface of the electrolyte substrate is coated with a precursor of either the cathode or the anode by the aerosol nano spray method, followed by heat treatment, and then another precursor is aerosol nano sprayed on the other side of the electrolyte substrate. It characterized by consisting of; electrode forming process of forming a cathode and an anode layer by performing a heat treatment after coating by.

The negative precursor is a commercially available micron particle size, characterized in that the NiO: Zr ₂ O ₃ : Y ₂ O ₃ ratio by weight ratio of 0.7: 0.05: 0.25.

The electrolyte precursor is a Y ₂ O ₃ / ZrO ₂ mixed nanopowder doped with a Y ₂ O ₃ : ZrO ₂ synthesis ratio of 8:92.

The electrolyte precursor is also diluted with xylene to make a slurry having a 50% content by weight of the powder, ball milling, and then 5% by weight of polyvinyl alcohol. After dilution with a ratio, it is characterized in that the weight ratio of the powder to 0.3% by using water.

The process of forming the electrolyte layer is characterized in that combustion is carried out by using a solution of zirconia (ZrO ₂ ) doped with yttria (Y ₂ O ₃ ) and oxygen and acetylene or a combination of oxygen and hydrogen as the combustion gas.

In the process of forming the electrolyte layer, the cathode is coated with the aerosol nano spray while heating the temperature of the anode (anode) to 900 ~ 1200 ℃.

The anode precursors include (LaSr) MnO _3, LaSrCoMnO ₃ , (La _0.8 Sr _0.2 ) (Co _0.8 Mn _0.2 ) O ₃ , (Sm _0.2 Ce _0.8 ) O ₂ , (La _0.8 Sm _0.2 ) MnO ₂ , SmCeO ₂ Or at least one of LaSrMnO ₃ as a base composition and diluting the submicron powder (<1 micron meter) of the base composition with an organic solvent of a poly vinyl alcohol base composition or a metal of the base composition. A salt containing an element is characterized in that it is any one diluted with water or alcohol.

The aerosol nano spray is carried out using a speedometer by applying a supply pressure of 10 to 30 psi for acetylene or hydrogen as a member of combustion gas, and a supply pressure of 15 to 40 psi for oxygen, and a precursor solution of 0.4 to It is characterized in that the feed through the combustion nozzle (nozzle) at a rate of 1.0 mg / cm ² .

The present invention described above allows the formation of ultra-thin (tens of tens to thousands of microns) of electrodes by a direct surface coating technique without going through the individual sintering process of each electrode layer as in the conventional fuel cell manufacturing technology. This facilitates the production of the unit electrode of the fuel cell, and provides the effect of making it possible to manufacture the unit electrode of the fuel cell having high performance electrical characteristics by appropriate selection of subsequent heat treatment.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a flow chart showing a process of the present invention, Figure 2 is a block diagram of the aerosol nano spray combustion apparatus of the present invention, Figure 3 is a side view of a unit electrode of a fuel cell manufactured by the present invention, Figure 4 is a cathode 5 is a plan view of a supported flat plate fuel cell electrode, and FIG. 5 is a graph showing electrical characteristics of a negative electrode supported flat plate fuel cell electrode according to an exemplary embodiment of the present invention.

In Figure 1 (a) is a flow chart showing the manufacturing process of the anode-supported flat fuel cell electrode, (b) is a flow chart showing the manufacturing process of the electrolyte-supported flat fuel cell electrode.

First, the manufacturing process of the anode-supported flat fuel cell electrode will be described with reference to FIG. 1A.

First, a negative electrode substrate having a thickness of about 1 mm is sintered to prepare a desired composition as a suspension precursor. As the negative electrode substrate 61, a commercial micron particle size powder was used, and the NiO: Zr ₂ O ₃ : Y ₂ O ₃ ratio was 0.7: 0.05: 0.25 by weight. As an electrolyte precursor, Y ₂ O ₃ doped submicron (1 <micron meter) ZrO ₂ powder is mixed with an organic solvent in a desired composition, diluted with an appropriate organic solvent (primarily xylene) and aerosol. It is used as a combustion raw material, or a salt containing Y and Zr is diluted with water or alcohol and used as an aerosol combustion raw material.

Likewise, as a precursor of the anode material layer to be coated with the next layer of electrolyte, a material based on LaSrCoMnO ₃ , SmCeO _2, or LaSrMnO ₃ is mainly used. Submicron powders (<1 micron meter) having these compositions are used as polyvinyl alcohol (Poly Vinyl Alcohol) Dilute with organic solvent of basic composition and use it as combustion material or salt containing each metal element is diluted with water or alcohol and used as combustion material. (S11)

Next, nano spraying is performed using the aerosol nano spray combustion apparatus of FIG. 2 and the suspension combustion material for electrolytes. In this process, zirconia (ZrO ₂ ) suspension 40 doped with yttria (Y ₂ O ₃ ) is used as a solution, and combustion gas 10 is combusted using oxygen and acetylene or a combination of oxygen and hydrogen. At this time, by applying the coating while heating the temperature of the prepared anode substrate (anode) to 900 ~ 1200 ℃ can improve the adhesion properties of the coating layer (cathode and electrolyte).

In the raw material spraying step, acetylene or hydrogen is supplied as a member of the combustion gas 10 at a supply pressure of 10 to 30 psi, and oxygen is supplied using a speedometer 20 by applying a supply pressure of 15 to 40 psi. The pump 30 is supplied through the combustion nozzle 50 at a rate of 0.4 to 1.0 mg / cm2. (S12)

As described above, the electrolyte layer coated on the negative electrode substrate may be improved by optimizing its adhesion and composition by appropriate heat treatment.

The anode material layer is then coated onto the electrolyte layer by nano spraying using the aerosol nano spray burner of FIG. 2. In order to form the anode coating layer, the basic composition of (LaSr) MnO ₃ is the most optimal composition, but if necessary, Co is added to the basic composition to use (La _0.8 Sr _0.2 ) (Co _0.8 Mn _0.2 ) O ₃ . . Or a material optimized for (Sm _0.2 Ce _0.8 ) O ₂ or (La _0.8 Sm _0.2 ) MnO ₂ composition. Nano powder or micron powder of selected composition is mixed with polyvinyl alcohol to make a well-dispersed slurry, and further diluted with water or alcohol to prepare a dilute raw material solution of appropriate concentration (mainly around 5% by weight weight of powder). As described above, as the combustion gas, hydrogen or acetylene gas can be used alone or together, and oxygen is used simultaneously. The gas supply pressure is carried out in the range described above, and the supply rate of the solution is in the range of 10 to 20 g / min (min).

The anode layer nano spray coating is carried out at room temperature, and after the coating of the appropriate thickness is completed, a heat treatment is performed in the range 900 ~ 1400 ℃ to form a rigid anode layer (S15).

The negative electrode supported flat fuel cell electrode formed by the above-described process is shown in FIGS. 3A and 4.

Next, a method of manufacturing an electrolyte-supported flat plate fuel cell electrode will be described with reference to FIG.

First, an electrolyte support layer is sintered to produce a precursor comprising a cathode and an anode material layer having a composition of a desired material. At this time, the composition ratio of the electrolyte layer, the positive electrode material layer, and the negative electrode material layer is the same as the description of the manufacturing process of the negative electrode-supported flat plate fuel cell electrode, and a detailed description thereof is omitted (S21).

A precursor for forming one of the anode and the cathode is coated on the electrolyte support layer using the aerosol nano spray burner of FIG. 2 (S22).

Next, heat treatment is performed to complete molding of one pole (S23).

When the molding of one pole is completed, the other surface of the electrolyte support layer is coated on the material support layer by using the aerosol nano spray burner of FIG. 2 to form another pole (S24).

Then, the forming of the other electrode is completed by performing heat treatment (S25).

An electrolyte supported flat fuel cell electrode formed by the process of FIG. 1B is shown in FIG. 3B.

To manufacture an ultra-thin solid oxide fuel cell, a cathode was selected by selecting an anode-supported planar type solid oxide fuel cell and setting a cathode (61) plate to be used as a substrate with an area of 100 x 100 mm ² . The substrate 61 was manufactured. Commercial micron particle size powder was used, NiO: Zr ₂ O ₃ : Y ₂ O ₃ ratio by weight ratio of 0.7: 0.05: 0.25 by mixing in an optimal technique and then sintered at 1400 ℃ for 1 hour to confirm the desired composition. Blocks prepared by the sintering technique were optimized to have a cross-sectional area of 100 x 100 mm ² , and wire discharge machining was performed to have a thickness of 1 mm after sintering.

Subsequently, an electrolyte precursor 40 was synthesized to coat the electrolyte by a nano spray process. First, a commercial Y ₂ O ₃ / ZrO ₂ mixed nanopowder doped with a Y ₂ O ₃ : ZrO ₂ synthesis ratio of 8:92 was diluted with xylene, and the powder was slurried at 50% by weight. (slurry) and after 24 hours ball milling (ball milling) again diluted with polyvinyl alcohol at 5% weight ratio, the final dilution so that the weight ratio of powder to 0.3% using water It was.

A precursor for electrolytic coating prepared in advance is coated using an aerosol nano spray combustion apparatus, and the supply amount of the precursor 40 is designated at a rate of 17 g / min, and the combustion gas uses hydrogen and oxygen. It was. The flow pressure of hydrogen was set to 20 psi and the pressure of oxygen was set to 30 psi. The electrolyte layer shaping was completed by setting the thickness of the electrolyte layer to about 10 microns (μm).

After finishing spray coating, annealing was performed at 1100 ° C. for 2 hours to maximize molding density of the electrolyte layer.

Subsequently, a slurry of the anode material 63 was synthesized to perform a cathode layer forming operation on the electrolyte-coated layer again by nano spray coating using the aerosol nano spray burner of FIG. 2. The designed composition was La _0.8 Sr _0.2 Co _0.8 Mn _0.2 and the powder particle size used was in the range of 500-700 nanometers. The nanopowder was diluted with polyvinyl alcohol using a commercially available dispersant called Duramax CT-324, which was first subjected to 50% by weight of the powder, followed by ball milling for 48 hours. . Then, distilled water was added again to dilute the powder content in the range of 5% by weight, and finally, isopropyl alcohol and distilled water were used to dilute the total powder to 0.3% by weight to secrete the nanospray precursor solution. .

Coating of the anode 63 layer was carried out using the prepared precursor 40 to set the supply flow rate to 18 g / min, the used combustion gas is hydrogen and oxygen, the supply pressure of hydrogen 30 psi, the pressure of oxygen is 40 Spraying was continued to set the psi so that the anode 40 had a thickness of about 40 microns. However, the spray was stopped in the middle of the coating and the heat treatment was performed at 1100 ° C. for about 1 hour to increase the density of the organic binder material and the molding layer.

After the coating of the anode layer, the coating was finally finished by subsequent heat treatment at 1100 ° C. for 2 hours.

5 shows the electrical characteristics of the unit electrode of the fuel cell formed according to the embodiment, and shows the results of performing the performance evaluation of the ultra-precision solid oxide fuel cell is completed at the use temperature of 500 and 750 ℃, respectively. The cathode side fuel used for the performance evaluation was hydrogen, and the anode side fuel was air. In the performance evaluation at 500 ° C, a voltage value of 0.6 V was shown at a current density of 700 mA / cm ² , and the maximum power density was about 420 mW / cm ² . In addition, the results of the performance evaluation at the operating temperature of 750 ℃ showed a voltage of about 0.6V at a current density of 900mA / cm ² and a maximum power density of 550mW / cm ² .

1 is a flow chart showing a process of the present invention,

2 is a block diagram of an aerosol nano spray combustion apparatus of the present invention,

3 is a side view of a unit electrode of a fuel cell manufactured by the present invention;

4 is a plan view of a negative electrode supported flat fuel cell electrode,

Figure 5 is a graph showing the electrical characteristics of the negative electrode supported plate fuel cell electrode according to an embodiment of the present invention.

Claims (9)

A precursor manufacturing process for producing a precursor of the positive electrode, the negative electrode and the electrolyte layer; A negative electrode support layer generating step of sintering a negative electrode substrate to be a negative electrode support layer using the negative precursor; Forming an electrolyte layer by coating a precursor of the electrolyte layer on the anode substrate by an aerosol nano spray method and then performing heat treatment; An anode layer forming process of forming an anode layer by coating the anode precursor on the electrolyte layer by an aerosol nano spray method and then performing a heat treatment. Electrode manufacturing method. A precursor manufacturing process for manufacturing a positive electrode, a negative electrode, and an electrolyte precursor; An electrolyte support layer generating step of sintering an electrolyte substrate which becomes an electrolyte support layer using the electrolyte precursor; One surface of the electrolyte substrate is coated with a precursor of either the cathode or the anode by the aerosol nano spray method, followed by heat treatment, and then another precursor is aerosol nano sprayed on the other side of the electrolyte substrate. Electrode forming method of forming a cathode and an anode layer by coating and then performing a heat treatment; and a method of manufacturing an electrode of a solid oxide fuel cell using a nanospray combustion apparatus, characterized in that consisting of. The nano-catalyst of claim 1 or 2, wherein the negative precursor is a commercial micron powder having a NiO: Zr ₂ O ₃ : Y ₂ O ₃ ratio in a weight ratio of 0.7: 0.05: 0.25. Electrode manufacturing method of solid oxide fuel cell using spray combustion apparatus. The method according to claim 1 or 2, wherein the electrolyte precursor is a Y ₂ O ₃ / ZrO ₂ mixed nano powder doped with a Y ₂ O ₃ : ZrO ₂ synthesis ratio of 8: 92. Electrode manufacturing method of a solid oxide fuel cell using a nanospray combustor characterized in that. The method according to claim 3, wherein the electrolyte precursor, Dilute with xylene to make a slurry with 50% content by weight of powder, ball milling, and dilute to 5% by weight with poly vinyl alcohol and then water A method of manufacturing an electrode of a solid oxide fuel cell using a nanospray combustor, characterized in that the weight ratio of the powder is 0.3% by using. The method of claim 1, wherein the electrolyte layer forming process is performed by using a zirconia (ZrO ₂ ) suspension doped with yttria (Y ₂ O ₃ ) as a solution and oxygen and acetylene or a combination of oxygen and hydrogen as a combustion gas. Electrode manufacturing method of a solid oxide fuel cell using a nanospray combustion apparatus, characterized in that. The solid oxide fuel using the nanospray combustor according to claim 6, wherein in the process of forming the electrolyte layer, coating is performed by the aerosol nanospray while heating the temperature of the anode substrate to 900 to 1200 ° C. Method for producing an electrode of a battery. The positive electrode precursor according to any one of claims 1 and 2, (LaSr) MnO _3, LaSrCoMnO ₃ , (La _0.8 Sr _0.2 ) (Co _0.8 Mn _0.2 ) O ₃ , (Sm _0.2 Ce _0.8 ) O ₂ , (La _0.8 Sm _0.2 ) MnO ₂ , SmCeO _2, or LaSrMnO ₃ With the above as the basic composition, the submicron powder (<1 micron meter) of the basic composition diluted with an organic solvent of polyvinyl alcohol basic composition or a salt containing a metal element of the basic composition ( A method for manufacturing an electrode of a solid oxide fuel cell using a nanospray combustor, characterized in that the salt) is diluted with water or alcohol. The method of claim 1, wherein the aerosol nano spray is performed, As a member of the combustion gas, acetylene or hydrogen is regulated using a speedometer at a supply pressure of 10 to 30 psi, oxygen at a supply pressure of 15 to 40 psi, and a precursor solution at a rate of 0.4 to 1.0 mg / cm ² . Electrode manufacturing method of a solid oxide fuel cell using a nanospray combustion apparatus, characterized in that the supply through a combustion nozzle (nozzle).

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