KR101346729B1 - Anode support for sold oxide fuel cell and manufacturing methods thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the formation of a cathode support, a cathode functional layer, and an electrolyte in a solid oxide fuel cell, wherein the thermal stress between the anode support and the electrolyte interface is small under oxidation and reduction conditions during use of the fuel cell, and also cracks during reoxidation. The present invention relates to a method of manufacturing a cell having a stable structure does not occur.

Description

Anode support for sold oxide fuel cell and manufacturing method thereof

The present invention relates to a negative electrode support for a solid oxide fuel cell and a method of manufacturing the same, and more particularly, in manufacturing a unit cell for a solid oxide fuel cell, it is possible to maintain a small difference in thermal expansion between the negative electrode support and the electrolyte under oxidizing or reducing conditions, and The present invention relates to a new negative electrode support capable of thinning.

The solid oxide fuel cell uses NiO-YSZ (Yttria-stabilized Zirconia) cermet, YSZ as electrolyte, and a high temperature of 750 ~ 1,000 ℃ by combining anodes such as (La, Sr) MnO ₃ . It is well known how to drive in.

In general, the cathode of a solid oxide fuel cell is a site where fuel oxidation occurs. During the manufacturing process, the cathode is subjected to a high temperature oxidation atmosphere. During operation, the cathode material is reduced by maintaining a hydrogen (H ₂ ) atmosphere. This is the factor that changes. When the negative electrode support is reexposed to air, the volume of the Ni metal is re-oxidized into NiO again in the pores of the negative electrode support, which causes a crack in the negative electrode support.

NiO-YSZ cermet is commonly known as a material used as the cathode, and ScSZ (Scandium-stabilized Zirconia) may be used instead of YSZ. ScSZ has twice the ion conductivity at the same temperature than YSZ, reducing the electrical resistance of the cell. The thermal and mechanical properties of YSZ and ScSZ are almost the same. NiO and the like are widely used as components for providing electron conductivity in NiO-YSZ summit, which is reduced to Ni under reaction conditions. In part, if fuel is supplied directly to CH ₄ instead of H ₂ , and the reforming reaction is stable in the cell, copper and cobalt may be added instead of nickel to suppress carbon coking.

The NiO to YSZ ratio in the negative electrode support is typically applied at 55:45 (weight ratio), which is the reduction of the several hundred S / It is known that it is necessary to express sufficient electrical conductivity of the cm level, and therefore, the NiO content is required to be higher than the YSZ content.

However, due to the large amount of NiO used, the effect of Nickel on the thermal expansion rate of the cathode support is large. However, in the general manufacturing process, the cathode support is limited to controlling the electrical conductivity and porosity for gas permeation after reduction. . That is, when the cell manufactured under the oxidation condition is changed to the use condition, that is, the reducing condition, the thermal expansion coefficient of the negative electrode support may be largely different from the thermal expansion coefficient of the electrolyte. Problems such as delamination or the like do not occur. In addition, when cells are exposed to air, they develop severe cracks, an example of which is shown in Solid State Ionics 176 (2005) 847-859.

In order to avoid this problem, thermal expansion characteristics and oxidation-reduction stability according to the material composition between the anode and the electrolyte in a solid oxide fuel cell have been proposed in US Pat. No. 7,351,487 B2 (2008). It shows little difference in thermal expansion rate, good electrical conductivity, no cracking and good cell performance. In this case, YSZ on NiO-YSZ cermet where cracks occur during redox was replaced with a rare-earth metal oxide composite with a single composition. However, in this case, the price is higher than that of YSZ, and material restrictions may occur in the case of mass production, and characteristics of repeated redox exposure are not suggested.

In addition, Japanese Patent Application Publication No. 10-2005-0004996 suggests a cell having increased mechanical strength by using 10YSZ (10mol% Y ₂ O ₃ substituted zirconia) instead of 8YSZ (8mol% substituted zirconia) in a NiO-YSZ cathode support. No changes were made to conditions or cell performance.

In addition, Korean Patent Laid-Open Publication No. 10-2005-0036914 discloses a secondary skeleton such as LaCrO ₃ and SrTiO ₃ having electrical conductivity through pores formed in the primary skeleton, after forming the primary skeleton of the cathode support using the first ceramic of YSZ. By supporting a ceramic material and firing the same, a method of manufacturing a negative electrode support having electrical conductivity without using metallic components such as Ni, Co, and Co is proposed. The purpose of this is to provide cell performance without excessive carbon deposition even in internal direct reforming of fuel cells, but the electrical conductivity is less than 1 S / cm and the performance of the manufactured cell is also not high, resulting in Ni-YSZ of several hundred S / cm. There is a lot to replace.

NiO-containing summits, such as NiO-YSZ, are effective for providing electrical conductivity and high cell performance of the cathode support, but ideally the mechanical skeleton of the cathode support in the NiO-YSZ summit is a basic skeleton in which YSZ and YSZ are directly connected. When NiO is present in the structure and distributed around the YSZ-YSZ skeleton, since the YSZ of the electrolyte and the YSZ of the negative electrode support skeleton are the same materials, the thermal expansion coefficients are the same regardless of the oxidizing conditions or the reducing conditions, and they are 1,000 ° C at room temperature. The thermal expansion between the cathode support layer and the electrolyte layer is the same for the temperature change up to, thus ensuring mechanical thermal stability between the electrode interfaces of the cell.

In practical cases, however, in the case of cathode support fabrication of planar type, especially flat tube or tubular solid oxide fuel cells, NiO is mixed with YSZ, binders, dispersants, water, etc. After forming an extrudate through the drying and drying in air, the organic material is calcined while raising the temperature, and the electrolyte is coated and calcined again, such as YSZ, and then sintered at 1,300 to 1,500 ° C. In the structure of the cathode support, not only the bond between YSZ and YSZ but also NiO-NiO bond is largely generated, which is a Ni-Ni bond upon reduction, which causes a rapid increase in the thermal expansion rate of the cathode support under operating conditions.

Usually, the thermal expansion rate of YSZ is about 10.5x10 ^-6 / ℃, NiO is about 10.5x10 ^-6 / ℃, and Ni is known to be more than 14.5x10 ^-6 / ℃, which is Ni-Ni connection part of cathode support under reducing conditions Increasing the coefficient of thermal expansion may cause thermal stress with the electrolyte YSZ layer or intensify thermal stress due to frequent temperature changes in long-term operation or non-operational cycles.

In particular, the cell reoxidation is accompanied by exposure to room temperature air after operating under high temperature reduction conditions. At this time, the effect on the cell crack may be increased by increasing the oxidation volume and reaggregation of NiO. In the related literature study [Solid State Ionics 176 (2005) 847-859], when the pore structure of the cathode support is minute, a large crack is generated in the entire support during the redox process. It suggests that it should consist of large pore (coarse).

This phenomenon is caused by the mechanical skeleton structure between the YSZ particles and the YSZ particles during the manufacturing process of the negative electrode support in the mixed state of NiO and YSZ particles, NiO or Ni is hard to be an ideal structure that is connected to and distributed around the YSZ skeleton. In the case of NiO-YSZ in a typical anode support fuel cell, many cracks are generated during or after use.

In another document [Journal of Power Sources 195 (2010) 1920-1925], a method of using a mixture of (Sr, Y) TiO ₃ system reduced at high temperature (about 1,400 ° C) as an electrical conductor and YSZ as an ion conductor is also used. Presented. Here, although the thermal expansion rate of (Sr, Y) TiO ₃ is almost similar to that of YSZ, the support is stable for the redox cycle, but (Sr, Y) TiO ₃ is exposed to air during use and once oxidized, Although the extinction rate is low, in order to dissipate the electrical conductivity and generate the required electrical conductivity, a disadvantage of requiring hydrogen reduction at about 1,200 ° C. or more is raised, which corresponds to the end of the life of the fuel cell. In addition, when the cathode support is made by mixing with YSZ as an ion conductor, an interfacial reaction occurs at high temperature, and the overall electrical conductivity is reduced to several tens of S / cm. In particular, the electrochemical reaction property required for the fuel cell is very weak, so The process of additionally supporting the nickel component is necessary, but a complicated method is required in which the supported nickel solution must penetrate to the interface with the electrolyte and be concentrated at its interface.

Therefore, nickel element with excellent electrochemical reactivity required in fuel cell is used, but minimizes the difference of thermal expansion between anode support and electrolyte in oxidation state or reduction state simultaneously to suppress interfacial separation between electrolyte and support and There is a need for a method to reduce thermal stress between interfaces, and at the same time, there is a need for a method that does not cause cracks due to NiO regeneration even after exposure to reoxidation atmosphere.

As is well known, in the case of coating an electrolyte such as YSZ on a cathode support such as NiO-YSZ, a porous cathode support is dip-coated with an electrolyte slurry solution to dry it. In the air, calcining is performed at about 300 to 700 ° C., and then densified and sintered at 1,300 to 1,500 ° C.

In this process, the skeletal structure of the NiO-YSZ anode support is also compacted and the pores are produced very small. This leads to a process in which the crack of the cell is caused by NiO volume increase and reagglomeration in the micro pores during redox reduction. In addition, in the NiO-YSZ negative electrode support, the thermal expansion difference between the NiO-YSZ negative electrode support and the YSZ electrolyte at high temperature does not differ in the oxidation condition, but has a disadvantage in that the reduction condition is large.

In order to improve this, the thermal expansion coefficient adjusting material having a lower thermal expansion coefficient than that of YSZ is partially used instead of the support YSZ, so that the thermal expansion rate of the negative electrode support in the oxidation state is slightly smaller than that of the electrolyte YSZ, but in the reduction state, it is larger than the electrolyte YSZ. There is a need for a method of approaching thermal expansion close to oxidation and reduction conditions based on electrolyte YSZ. In addition, when using a material having a smaller thermal expansion coefficient together with YSZ or the like, it is also necessary to maintain a certain amount of pores in the support in the range of 0.1 to 20 µm after sintering at 1,300 to 1,500 ° C.

The negative electrode support undergoes co-sintering at high temperature (1,300 ~ 1,500 ℃) with the electrolyte YSZ layer coated on the negative electrode support, resulting in shrinkage. At the same time, the electrolyte YSZ particle layer is also densified. The leak hole gradually disappears, the YSZ grain grows, and the grain boundary decreases.

However, when the cathode support is coarse and the pores are large, the pore of the support may provide a more stable structure during reoxidation after the side of the cell or the cell operation, whereas the leak holes in the coated electrolyte YSZ, etc. Residual and large amounts of grain boundaries can be present, which is a contradictory factor that significantly reduces the performance of fabricated cells. In addition, when sintering characteristics of particles are delayed to delay volume shrinkage during sintering of the negative electrode support to maintain large pores, the coating of electrolyte YSZ particles is uneven, and as a leak hole through which H ₂ or O ₂ passes through the electrolyte YSZ layer after sintering. Existing or YSZ grain boundaries also remain and may cause H ₂ or O ₂ leak during operation.

This phenomenon may be contrary to the fact that the coarse of the negative electrode support can make cells stable to redox and that the densification of the electrolyte YSZ layer should be well performed. There is a need for a new method that simultaneously maintains the pore structure of the negative electrode support and densifies the electrolyte. In particular, when the thermal expansion control oxide is added, the sintering speed may be lower than that of the cermet of NiO / YSZ itself. This may help to form pores roughly, but may be an obstacle to the dense sintering of the cathode functional layer or the electrolyte layer. May remain.

In order to induce densification of the anode functional layer or electrolyte layer, which is coated even in the case of high volume (1,300 ~ 1,500 ° C) sintering with coarse pores, the solution dip of the cathode functional layer or electrolyte layer on the anode support After the coating, before the drying step, in a separate device, it is necessary to apply a vacuum to the inside of the negative electrode support to remove the solvent and to increase the density between the coating layer particles, followed by drying, firing and sintering.

In order to achieve the above object, in the present invention, the thermal expansion rate of the negative electrode support in the oxidized state is controlled to be lower than that of the electrolyte layer, and at the same time, it is higher than the electrolyte layer in the reduced state, so that the degree of thermal expansion of the electrolyte and the negative electrode support under both high-temperature redox conditions It is to provide a method for making the difference in the degree of thermal expansion similar.

At the same time, there is provided a method of forming a stable anode functional layer and an electrolyte layer on a cathode support having a large porosity while preventing cracking of cells under repeated redox conditions even under the coarse porosity of a cathode support having a controlled thermal expansion. have.

The present invention solves the above problems, so that the anode support can be used to produce a stable and durable cell under the redox conditions, NiO-YSZ Summit or NiO-SzSZ Summit, etc. can be used, wherein a part of YSZ or ScSZ Is mixed with spinel such as CaAl ₂ O ₄ , MgAl ₂ O ₄ , NiAl ₂ O ₄ , CuAl ₂ O ₄ , CoAl ₂ O _4, and oxides such as Y ₂ O ₃ and Yb ₂ O ₃ , which have lower coefficient of thermal expansion. A method of use is provided, wherein the proportion of additional oxide in the mixture with YSZ (or ScSZ) is 10 to 90% by weight. At this time, the thermal expansion coefficient of the oxide for further thermal expansion control is 7.0x10 ^-6 / ℃ ~ 10.0x10 ^-6 / ℃, the average particle is larger than the YSZ, larger than the average 0.1㎛, preferably larger than 0.3㎛ and smaller than 10㎛. Typically, the thermal expansion coefficient of YSZ is 10.8 × 10 ⁻⁶ / ° C., and the thermal expansion coefficient of Y ₂ O ₃ is about 8.1 × 10 ⁻⁶ / ° C.

Here, the mixture of NiO-YSZ as a two-component form of NiO-YSZ to be a summation by mixing with NiO alone does not exhibit the effect sought in the present invention, which is a thermal expansion with the electrolyte layer in the process prepared under oxidizing conditions This is because a large difference occurs, and accordingly, in the case of YSZ, mixed with another oxide for thermal expansion coefficient adjustment, but at least 10% or more may be used to increase the effect.

On the other hand, when the thermal expansion control oxide is mixed with the one selected from YSZ or ScSZ, instead of YSZ or ScSZ, GDC (Gadollium-doped Ceria) having good ion conductivity or reducing stability and electrical conductivity and good thermal expansion rate is YSZ. It is also possible to substitute and mix some of YSZ or ScSZ with Perovskite oxides such as (Sr, Y) TiO ₃ and (Y, Sr) CrO ₃ , which are very similar to.

The cell of the present invention is prepared by manufacturing a negative electrode support having a controlled thermal expansion coefficient, coating and vacuuming the negative electrode functional layer and the electrolyte layer, followed by dry firing, and then coating and firing the positive electrode layer.

The negative electrode support mixes NiO in an amount of about 30-70 wt%, YSZ (or ScSZ, etc.) and a mixture of thermal expansion control oxide at a ratio of about 30 to 70 wt%, but considering the low specific gravity of added thermal expansion control oxide, Can be adjusted. Usually, the thermal expansion control oxide has a low specific gravity, and in this case, the thermal expansion control oxide occupies a relatively large volume, so there is no significant difference in the overall volume composition even if NiO is increased. 1 to 10 wt% of activated carbon or carbon black is added thereto as a pore control agent and ball milled on the ethanol solution for at least one day to volatile ethanol.

1 to 10 wt% binder, 1 to 5% dispersant, and the like are added to the homogeneously mixed powder mixture, and then kneaded for 5 hours or more, and then aged for 2 days, and then extruded in a flat or tubular extruder. The extruded molded product is dried and then burned away from organic materials at 1,000 ~ 1,300 ℃ in the kiln, and then fired and sintered. At this time, the temperature rise is maintained at 5 ℃ / min.

In the present invention, to prevent the formation of holes in the electrolyte layer due to the coarse pores of the negative electrode support, to increase the bonding strength with the electrolyte layer, and to increase the reaction active point (TPB) in the negative electrode layer / electrolyte layer Cathode functional layer is coated. NiO-YSZ or NiO-ScSZ is used for the cathode functional layer, but the NiO ratio is preferably about 50 wt% compared to the mixture with YSZ or ScSZ, but not more than about 53%, and the thickness of the final coating layer is 3-15. M, preferably 5 to 10 m.

In the present invention, the negative electrode functional layer is a NiO-YSZ or NiO-ScSZ slurry solution to dip-coating the negative electrode support under normal pressure (coating) to a uniform thickness, and then take it out and vacuum the inside of the support in a separate device To remove the solvent from the coating layer while simultaneously providing a dense coating layer. This provides an effective method of increasing the connectivity between particles while suppressing particle separation of NiO or YSZ during drying or heating. The support coated with the negative electrode functional layer is calcined at about 900 to 1,200 ° C. and then used for electrolyte coating.

In the present invention, the electrolyte coating is carried out by dip-coating under atmospheric pressure, in particular, in the case of a large cell, the electrolyte is coated with a uniform thickness only when the dip coating is performed under normal pressure. The coating thickness finally has a thickness of about 5 ~ 30㎛ but preferably used about 10 ~ 15㎛. In the present invention, after the dip coating is carried out under atmospheric pressure, the support is taken out and vacuumed inside the support in a separate device to remove the solvent from the surface and the inner surface of the support while simultaneously densifying the YSZ or ScSZ particles, thereby increasing the compactness during sintering and generating a leak hole. It provides a way to prevent. The dip coating of the electrolyte is preferably performed two or more times. The first sintering of the anode support coated with the electrolyte is performed at 1,100 to 1,300 ° C, and the final sintering is performed at 1,300 to 1,500 ° C to obtain a densified electrolyte membrane. At this time, the temperature rise is less than 5 ℃ / min.

The anode layer is usually LSM-YSZ, LSM-ScSZ, LSCF ((La, Sr) (Co, Fe) O ₃ ) -GDC ((Ga, Ce) O ₂ ), etc., and can be used for screen printing or tape casting. After coating it is used by firing at about 1,000 ~ 1,200 ℃.

The present invention provides a solid oxide fuel cell manufactured in a high temperature oxidizing atmosphere and operating in a reducing atmosphere, in which the negative electrode support maintains high electrical conductivity while reducing the difference in high temperature thermal deformation in an oxidizing and reducing atmosphere, thereby reducing the heat between the negative electrode support and the electrolyte. No stress or interfacial separation occurs, and at the same time, even when converted into an oxidizing atmosphere, cracks do not occur in cells including the negative electrode support due to NiO volume expansion due to Ni reoxidation, and the pores of the negative electrode support are largely maintained. By providing a dense and thin electrolyte layer, the present invention provides a solid oxide fuel cell that has high cell performance and is stable at high temperature.

Hereinafter, the present invention will be described in detail with reference to examples. The following examples are described in detail, but are intended to illustrate the invention and are not intended to limit the invention.

Comparative Example

The negative electrode support was mixed with NiO at 55 wt% and YSZ 45%, and 10 wt% of activated carbon was added as a pore regulator to ball mill the ethanol solution for at least 1 day to uniformly mix and take out the ethanol to dry volatilize it.

5 wt% binder, 3% dispersant and the like are added to the homogeneously mixed powder mixture, and then kneaded for at least 5 hours, aged for 2 days, and extruded in a flat tube extruder.

The extruded molded product was dried and then burned off the organic material while heating at 3 ° C./min to 1,100 ° C. in a kiln to prepare a negative electrode support. At this time, the porosity was 45%.

Using the prepared negative electrode support, the negative electrode functional layer slurry solution having the composition of NiO-YSZ 55:45 wt% was dip-coated under normal pressure, dried in an air state, and then placed in a heating furnace and calcined while heating at 3 ° C./min to 1,200 ° C. . The thickness of the cathode functional layer after the fabrication of the cell was about 15㎛ and maintained almost the same shape as the cathode support.

The negative electrode support coated with the negative electrode functional layer as described above was put in an YSZ electrolyte slurry solution, and was dip-coated under normal pressure. This was taken out and dried in air to remove the solvent. This was put into a heating furnace in the air state and was performed twice while heating at 3 ° C./min to 1,200 ° C., and the second sintering was performed at 1,400 ° C. After fabrication of the final cell, the thickness of the electrolyte was 17 μm. The average porosity of the support in the oxidized state was 20% and the average porosity was 0.6 μm.

In the state prepared as described above, a cathode slurry prepared by mixing (La, Sr) MnO ₃ and YSZ in a weight ratio of 60:40 was prepared, coated and dried, and again (La, Sr) (Co, Fe) O ₃ The slurry was coated and dried, and then fired by heating to 1,150 ° C. in a heating furnace to prepare an SOFC cell.

Attach the SOFC cell to the fuel cell test device, heat it down to 650 ℃ while flowing hydrogen (H ₂ ), reduce the open circuit voltage (OCV) to 1.0V, and raise it to 800 ℃ The performance was measured.

After the H ₂ supply was stopped (off) and after 5 hours, H ₂ supply was started again and the current voltage characteristics were measured. Then, the temperature was lowered and the crack state was observed in the cell. The results of these runs are shown in Table 1.

Example 1

The negative electrode support was mixed with 20 wt% of YSZ and 20 wt% of the thermal expansion control oxide MgAl ₂ O ₄ , and NiO corresponding to about 60 wt% was added thereto. 10 wt% of carbon black was added thereto as a pore control agent, and ball milled for at least one day on an ethanol solution to uniformly mix, and the ethanol was dried and volatilized. The average particle size of YSZ used was 0.5 μm and MgAl ₂ O ₄ particles averaged 2 μm.

5 wt% binder, 3% dispersant, and the like were added to the homogeneously mixed powder mixture, and then kneaded for 5 hours or more, and aged at room temperature for 2 days, and then extruded in a flat tube extruder.

The extruded molded article was dried and then heated to 3,100 / min in a firing furnace to burn off the organic material to prepare a negative electrode support.

For negative electrode functional layer coating NiO / YSZ 48:52 wt% and prepared a lower concentration slurry solution than the comparative example, the prepared negative electrode support was dip-coated to the negative electrode functional layer slurry solution under normal pressure. This was removed, and vacuum was applied to the inside of the support in a separate apparatus at about 50 torr to remove the solvent contained in the support and the solvent present in the outer coated layer. This was put into a heating furnace in the air and calcined while heating at 3 ° C / min to 1,200 ° C. After preparing the cell, the thickness of the negative electrode support was about 10 μm.

The negative electrode support coated with the negative electrode functional layer as described above was put in a lower concentration of the YSZ electrolyte slurry solution than the comparative example, and was dip-coated with the electrolyte slurry solution under normal pressure. This was removed and vacuum was applied to the inside of the support in a separate apparatus at about 50 torr to remove the solvent contained in the support and the solvent present in the outer coated layer. It was dried in the air and then put into a heating furnace, and was carried out twice while heating at 3 ° C./min to 1,200 ° C., and the second sintering was performed at 1,400 ° C. After fabrication of the final cell, the thickness of the electrolyte was 13 μm. The average porosity of the support in the oxidized state was 23% and the average porosity was 1.2 μm.

In the state prepared as described above, a cathode electrode prepared by mixing (La, Sr) MnO ₃ and YSZ 60:40 was prepared, coated and dried, and the slurry composed of (La, Sr) (Co, Fe) O ₃ again thereon. After coating the coating and dried, it was calcined by heating to 1,150 ℃ in a heating furnace to produce a SOFC cell.

Attach the SOFC cell to the fuel cell test device, heat it down to 650 ℃ while flowing hydrogen (H ₂ ), reduce the open circuit voltage (OCV) to 1.0V, and raise it to 800 ℃ The performance was measured.

After the H ₂ supply was stopped (off) and after 5 hours, H ₂ supply was started again and the current voltage characteristics were measured. Then, the temperature was lowered and the crack state was observed in the cell. The results of these runs are shown in Table 1.

Example 2

A negative electrode support was prepared as in Example 1, except that ScSZ was used instead of YSZ in the anode functional layer, the electrolyte, and the cathode layer. The results of these runs are shown in Table 1.

Example 3

A cell was prepared as in Example 1 except that the vacuum treatment was not performed during the preparation of the anode functional layer and the electrolyte in Example 1. The results of these runs are shown in Table 1.

Example 4

Except that NiO 58% was used in the powder mixed with 18% YSZ, 12% MgAl ₂ O _4, 12% Y ₂ O ₃ in the negative electrode support was carried out as in Example 1. The results of these runs are shown in Table 1.

cell test results Cell test initial Restart after H ₂ interruption crack occurrence
OCV peak power
mW / ㎠ @ 800 ℃ OCV peak power
mW / ㎠ @ 800 ℃ Comparative Example 1.05 270 0.67 90 crack occurrence Example 1 1.06 350 1.05 340 no crack Example 2 1.06 450 1.05 440 no crack Example 3 0.95 230 0.95 225 no crack Example 4 1.06 360 1.05 355 no crack

Claims (20)

In the NiO-YSZ or NiO-ScSZ cathode support, a portion of the YSZ or ScSZ is replaced with a thermal expansion control oxide having a lower thermal expansion rate to prepare a negative electrode support,
Here, the thermal expansion control oxide is selected from the group consisting of CaAl ₂ O ₄ , MgAl ₂ O ₄ , NiAl ₂ O ₄ , CuAl ₂ O ₄ , FeAl ₂ O ₄ , Y ₂ O ₃ , Yb ₂ O ₃ ;
Coating a cathode functional layer on the cathode support; And
Coating an electrolyte layer on the cathode functional layer
≪ / RTI > The method of claim 1, wherein the coating of the cathode functional layer comprises
Dip coating the negative electrode support into the slurry solution; And
A method of manufacturing a solid oxide fuel cell, comprising removing the solvent and applying a vacuum to the inside of the cathode support to remove the solvent remaining in the anode support and the coating layer, followed by drying and baking. The method of claim 1 or 2, wherein the coating of the electrolyte layer
Dip coating the negative electrode support coated with the negative electrode functional layer on the slurry solution for the electrolyte; And
A method of manufacturing a solid oxide fuel cell, comprising removing the same and applying a vacuum to the inside of the negative electrode support to remove the solvent remaining in the negative electrode support, the negative electrode functional layer, and the electrolyte coating layer. delete The method of claim 1, wherein the thermal expansion rate of the thermal expansion control oxide is 7.0x10 ^-6 / ℃ ~ 10.0x10 ^-6 / ℃ less than YSZ. The method of claim 1, wherein 10 to 90% by weight of YSZ or ScSZ is replaced by the thermal expansion control oxide. The method for manufacturing a solid oxide fuel cell according to claim 1, wherein the thermal expansion control oxide has a mean particle size of 0.3 µm-10 µm with a large average particle size of YSZ. The method of claim 1, wherein the cathode functional layer is made of NiO-YSZ, NiO-SzSZ, or NiO-GDC. The method of claim 8, wherein the negative electrode functional layer has a NiO content of 45-53 wt% and a coating thickness of the negative electrode functional layer is 3 to 15㎛. The method of claim 1, wherein the electrolyte layer is formed of YSZ, ScSZ, or GDC, and has a thickness of 5 to 30 μm after cell fabrication. The method of claim 1, further comprising GDC, (Sr, Y) TiO ₃ , and (Y, Sr) CrO ₃ oxides. delete delete delete delete delete delete delete delete delete