JP4620572B2 - Solid oxide fuel cell and method for producing the same - Google Patents

Description

  The present invention relates to a solid oxide fuel cell composed of an electrolyte layer made of an oxide such as ceramic and a method for producing the same.

  In recent years, there has been an increasing interest in solid oxide fuel cells using an oxygen ion conductor as a solid oxide electrolyte layer. In particular, from the viewpoint of effective use of energy, a solid oxide fuel cell is essentially free from restrictions on Carnot efficiency (limit of heat energy use efficiency), and thus has essentially high energy conversion efficiency. Furthermore, the solid oxide fuel cell has excellent features such as good environmental protection (see Non-Patent Document 1).

By the way, since the solid oxide fuel cell initially has a high operating temperature of 900 to 1000 ° C. and all members are made of ceramic, it is not easy to reduce the manufacturing cost of the cell stack. If the operating temperature can be reduced to 800 ° C. or less, preferably about 700 ° C., a heat-resistant alloy material can be used for the interconnector (separator), and the manufacturing cost can be reduced. For example, perovskite-based metal oxides, such as La (NiFe) O ₃ , that have nickel and iron at the B site, have high electrode activity, and this can be used for the air electrode to lower the operating temperature. it can. However, as the operating temperature decreases, for example, the rate of chemical reaction at the air electrode decreases, and the overvoltage, which is an electrochemical resistance, increases rapidly, resulting in a decrease in output voltage.

  By the way, in the solid oxide fuel cell using the material as described above, each electrode or electrolyte layer is composed of a sintered body (ceramic) of fine particles (powder) of each material. For this reason, it is possible to obtain higher electrode characteristics by increasing the length of the interface (three-phase interface) where the electrode / electrolyte / gas three-phase interface where the electrode reaction proceeds is expanded. Therefore, the above-described decrease in output voltage due to the decrease in operating temperature can be eliminated by increasing the three-phase interface length.

  In order to increase the three-phase interface length, for example, the ceria (cerium oxide) -based material powder that conducts oxygen ions and the powder that constitutes the air electrode are mixed in the same way as the electrolyte layer. There is a technique of using the sintered body as an intermediate layer. The ceria-based material does not cause reaction deterioration with the perovskite-based air electrode material described above, and can be used for the intermediate layer. By providing such an intermediate layer between the electrolyte layer and the air electrode, the substantial contact area between the electrolyte layer and the air electrode is increased, and an increase in the three-phase interface length can be expected.

Hiroaki Tagawa, “Solid Oxide Fuel Cell and Global Environment”, Agne Jofusha Co., Ltd., 1998.

  However, the ceria-based material conducts oxygen ions, while the material composing the air electrode conducts electrons. Therefore, the mixture of these powders cuts the conduction path of each other. Together, it interferes with the conduction of oxygen ions and electrons. In particular, since the conductivity of oxygen ions at 700 to 800 ° C. is about three orders of magnitude lower than the conductivity of electrons, if the oxygen ion conduction path is not sufficiently secured, the output is reduced. .

  The present invention has been made to solve the above-described problems, and a conduction path of oxygen ions in an intermediate layer made of a ceria-based material that conducts oxygen ions and a material that constitutes an air electrode is provided. The purpose is to provide a more formed state.

  A method for producing a solid oxide fuel cell according to the present invention includes a step of forming a fuel electrode on one surface of an electrolyte layer made of a sintered metal oxide powder, and an electrolyte layer. Forming a porous ceria sintered body layer composed of a sintered body of a cerium oxide powder doped with a metal oxide on the other surface of the metal, and ceria sintering A step of impregnating the body layer with a metal solution in which ions of the metal constituting the perovskite oxide are dissolved, and after the ceria sintered body layer is formed, the perovskite oxide is formed on the other surface of the electrolyte layer. A step of applying a slurry in which powder is dispersed to form an air electrode coating film, a step of firing the air electrode coating film to form an air electrode, and a metal solution impregnated By firing the ceria sintered body layer in an atmosphere containing oxygen, At least a step of forming an intermediate layer in which the metal oxide crystal grains containing at least lanthanum are deposited in the porous pores of the ceria sintered body layer on the other surface of the electrolyte layer, The intermediate layer is formed between the electrolyte layer and the air electrode.

  The cerium oxide powder may be any cerium oxide powder doped with at least one of yttrium oxide, samarium oxide, and gadolinium oxide. In addition, the metal solutions are “dissolved lanthanum ions, nickel ions and iron ions”, “dissolved lanthanum ions, strontium ions and iron ions”, “lanthanum ions and cobalt ions”. At least one of “dissolved ions” and “dissolved lanthanum ions, cobalt ions, and strontium ions”. Further, a ceria sintered body layer is formed from a sintered body obtained by adding metal oxide powder containing lanthanum for forming an air electrode to cerium oxide powder doped with metal oxide. Also good.

  In the method for producing a solid oxide fuel cell, the step of impregnating the ceria sintered body layer with a metal solution in which metal ions are dissolved may be performed before the air electrode coating film is formed. Further, the step of impregnating the ceria sintered body layer with the metal solution in which metal ions are dissolved may be performed after the air electrode coating film is formed. Further, the step of impregnating the ceria sintered body layer with the metal solution in which metal ions are dissolved may be performed after the air electrode is formed.

  A solid oxide fuel cell according to the present invention includes an electrolyte layer made of a sintered metal oxide powder, a fuel electrode formed on one surface of the electrolyte layer, and an electrolyte layer. At least an intermediate layer formed on the other surface, and an air electrode formed on the intermediate layer and made of a sintered body of a perovskite oxide, the intermediate layer is doped with a metal oxide A porous ceria sintered body layer composed of a sintered body of cerium oxide powder was impregnated with a metal solution in which ions of the metal constituting the perovskite oxide were dissolved, and the metal solution was impregnated. It is formed by firing a ceria sintered body layer, and crystal grains of a perovskite oxide made of the above metal ions are precipitated in the porous pores of the ceria sintered body layer.

  The cerium oxide powder may be any powder doped with at least one of yttrium oxide, samarium oxide, and gadolinium oxide. The metal solution is a solution of lanthanum ions, nickel ions and iron ions, lanthanum ions, strontium ions and iron ions, lanthanum ions and cobalt ions. And at least one in which lanthanum ions, cobalt ions and strontium ions are dissolved. The ceria sintered body layer may be a sintered body obtained by adding metal oxide powder containing lanthanum for forming an air electrode to powder of cerium oxide doped with metal oxide. .

  As described above, in the present invention, the ceria sintered body layer impregnated with the metal solution is fired in an atmosphere containing oxygen, so that the perovskite oxide crystal grains are porous in the ceria sintered body layer. The intermediate layer deposited in the holes was formed on the other surface of the electrolyte layer. As a result, according to the present invention, the oxygen ion conduction path in the intermediate layer made of the ceria-based material that conducts oxygen ions and the material that forms the air electrode is more excellently formed. An effect is obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram showing an example of a method for producing a solid oxide fuel cell according to an embodiment of the present invention. First, as shown in FIG. 1A, a zirconia (metal oxide) powder to which Sc ₂ O ₃ and Al ₂ O ₃ are added is dispersed in a predetermined medium to prepare a slurry. Is formed by a well-known doctor blade method, and is baked to form an electrolyte layer 101 having a thickness of 0.2 mm. As the above powder, it is sufficient to use ZrO ₂ at 89, Sc ₂ O ₃ at 10, Al ₂ O ₃ at 1, and Sc ₂ O ₃ and Al ₂ O ₃ added to zirconia.

Next, a slurry obtained by adding 60 w% of nickel oxide powder having an average particle diameter of 0.2 μm to zirconia powder having an average particle diameter of 0.6 μm and mixing the mixture is applied by, for example, a screen printing method, and dried to thereby obtain an electrolyte. A fuel electrode coating film is formed on one surface of the paste plate. As the zirconia powder in a proportion of ZrO ₂ is 92, Y ₂ O ₃ is 8, may be used ZrO ₂ to Y ₂ O ₃ was added. Next, a current collector layer made of platinum mesh is placed on the formed fuel electrode coating film, and these are fired in air at 1400 ° C. for 8 hours, whereby one surface of the electrolyte layer 101 is placed. It is assumed that the fuel electrode 102 is formed on the (lower surface in FIG. 1) together with the current collector layer (omitted in FIG. 1).

Next, a slurry is prepared by dispersing a powder of Ce _0.8 Y _0.2 O ₂ (YDC: solid solution in which ceria is doped with yttrium oxide) in a predetermined medium, and this slurry is screen-printed. The other surface (upper surface in FIG. 1) of the electrolyte layer 101 is applied by a method and dried to form a ceria-based material coating film. Next, the formed ceria-based material coating film is baked at 1100 ° C. to form a ceria sintered body layer 113 having a thickness of 4 μm on the other surface of the electrolyte layer 101 as shown in FIG. It is assumed that

  Next, the ceria sintered body layer 113 is impregnated with a metal solution containing lanthanum (La), nickel (Ni), and iron (Fe) as ions (dissolved). For example, a step of dropping a metal solution onto the ceria sintered body layer 113 to infiltrate it and drying it may be repeated three times. Since the ceria sintered body layer 113 is formed in a porous state, the dropped metal solution penetrates into the ceria sintered body layer 113. In addition, what is necessary is just to use the solution of the organometallic compound which consists of La, Ni, and Fe, for example as the said metal solution. Further, the metal solution may be an aqueous solution containing La ions, Ni ions, and Fe ions at a predetermined concentration. The metal contained in these metal solutions is the metal which comprises the perovskite type oxide which can comprise an air electrode so that it may demonstrate later.

Next, a perovskite oxide powder capable of forming an air electrode, such as LaNi _0.6 Fe _0.4 O ₃ (LNF) powder having an average particle diameter of 1.5 μm, is dispersed in a predetermined medium to produce a slurry. To do. Next, the produced slurry is applied onto the ceria sintered body layer 113 by a screen printing method and dried to form a state where an air electrode coating film is formed. Next, a current collector layer made of platinum mesh is placed on the formed air electrode coating film, and these are fired at 1000 ° C. for 2 hours in an atmosphere containing oxygen such as air. As a result, as shown in FIG. 1C, the intermediate layer 103 is formed on the other surface of the electrolyte layer 101, and the air electrode 104 is placed on the current collector layer (in FIG. 1). (Not shown).

  As described above, when the ceria sintered body layer impregnated with the metal solution is heated (fired) in an oxygen atmosphere, the metal oxide (perovskite oxide) contained in the impregnated metal solution as ions is included. Crystal grains) are precipitated as crystals in the porous pores of the ceria sintered body. As described above, the intermediate layer 103 is made of, for example, LNF or the like in a plurality of fine holes of the ceria sintered body layer by firing the metal solution impregnated in the porous ceria sintered body layer. This is a state in which fine crystals (crystal grains) of the perovskite oxide are precipitated.

  In other words, the intermediate layer 103 is formed by arranging fine crystals responsible for electron conduction in fine pores of a ceria sintered body made of a ceria-based material responsible for oxygen ion conduction. Therefore, in the intermediate layer 103, the oxygen ion conduction path is sufficiently formed. The intermediate layer 103 is a mixture of a material (powder) that conducts oxygen ions and a material (powder) that constitutes the air electrode. The substantial contact area with the air electrode 104 is increased, and the three-phase interface length is increased.

  By the way, in the above description, the ceria sintered body layer 113 is impregnated with the metal solution described above immediately after the ceria sintered body layer 113 is formed (before the air electrode is formed). Absent. For example, the ceria sintered body layer 113 may be impregnated with the metal solution after the air electrode coating film is formed. Alternatively, the ceria sintered body layer 113 may be impregnated with the metal solution after the air electrode is formed by firing.

  In the above description, the ceria sintered body layer 113 is composed of a YDC powder sintered body, but is not limited thereto. For example, a mixed powder obtained by adding and mixing LNF powder to YDC powder is dispersed in a predetermined medium to prepare a slurry, and this slurry is applied and fired to form a ceria sintered body layer. Good. As the LNF powder, one having an average particle diameter of 1.5 μm is generally available as shown in the air electrode formation described above. The particle size of LNF powder cannot be made very small, and as described above, the particle size is larger than that of YDC powder.

  Therefore, even if the LNF powder is mixed with the YDC powder, the formed ceria sintered body layer is in a state where the YDC fine particles are adhered so as to cover the surface of the LNF particles. As a result, even if the LNF powder is mixed, the contact between the YDC fine particles is unlikely to be disturbed, and the conduction path of oxygen ions by the plurality of YDC fine particles connected to each other is sufficiently secured. can get. Further, by mixing the LNF powder to form the ceria sintered body layer, the three-phase interface length can be further increased.

In the above description, YDC is used as the ceria-based material for forming the ceria sintered body layer. However, the present invention is not limited to this. For example, Ce _0.8 Sm _0.2 O ₂ (SDC: solid solution in which ceria is doped with samarium oxide) and Ce _0.8 Gd _0.2 O ₂ (GDC: solid solution in which ceria is doped with gadolinium oxide) may be used.

In addition, as the metal solution impregnated in the ceria sintered body layer, a solution containing La, Ni, and Fe as ions is used. However, the present invention is not limited to this. Any metal solution may be used as long as it dissolves metal ions constituting the perovskite-type oxide that can take charge of electron conduction (can constitute an air electrode). Such a perovskite oxide is generally represented as ABO ₃ by two metal A atoms, metal B atoms and three oxygen atoms. In addition to La, the metal A includes rare earth elements such as praseodymium (Pr), neodymium (Nd), samarium (Sm), and gadolinium (Gd), and the metal B includes transition metals such as Fe, Ni, and Co. There is.

Therefore, as the metal solution impregnated in the ceria sintered body layer, for example, a metal solution containing La, strontium (Sr), and Fe as ions may be used. In this case, by appropriately setting the composition ratio of ions of each element, for example, a state in which a metal oxide having a composition of La _0.5 Sr _0.5 FeO ₃ is precipitated as crystals in the porous pores of the ceria sintered body. can get. Alternatively, a metal solution containing La and cobalt (Co) as ions may be used as the metal solution impregnated in the ceria sintered body layer. In this case, for example, a state is obtained in which a metal oxide having a composition of LaCoO ₃ is precipitated as crystals in the porous pores of the ceria sintered body. Alternatively, a metal solution containing La, Co, and Sr as ions may be used as the metal solution impregnated in the ceria sintered body layer. In this case, for example, a state is obtained in which a metal oxide having a composition of La (Sr) CoO ₃ is precipitated as crystals in the porous pores of the ceria sintered body.

In addition, although LNF is used as the powder of the electron conductive medium added to the ceria sintered body layer, the present invention is not limited to this, and a powder of La _0.8 Sr _0.2 FeO ₃ (LSF) may be used. Good. For example, LSF powder having an average particle size of 1.0 μm can be used. When adding LSF to the ceria sintered body layer (intermediate layer), the air electrode may also be composed of LSF.

  Next, a description will be given of the result of measuring the interface resistance on the air electrode side in each sample cell manufactured by changing the sintered body layer, the metal solution to be impregnated, and the material used for the air electrode. A sample cell was used to obtain a solid oxide fuel cell as shown in the cross-sectional view of FIG. The solid oxide fuel cell shown in FIG. 2 will be described. A fuel electrode 102 and a current collector layer 105 are stacked on one surface of an electrolyte layer 101 having a thickness of 0.2 mm, and an intermediate layer 103 and air are stacked on the other surface. The electrode 104 and the current collector layer 106 are stacked. In addition, as shown in the perspective view of FIG. 3, a reference electrode 107 made of platinum is provided on the periphery of the other surface of the electrolyte layer 101.

  In addition, an end portion of a cylindrical fuel gas exhaust pipe 201 is fixed to one surface of the electrolyte layer 101 so as to surround a region where the fuel electrode 102 is disposed, and the fuel gas exhaust pipe 201 has fuel inside. A gas supply pipe 202 is arranged. The fuel gas (hydrogen gas) introduced through the fuel gas supply pipe 202 is supplied to the region of the fuel electrode 102 from the discharge end of the fuel gas supply pipe 202. Further, the gas discharged from the fuel electrode 102 is taken out from a region outside the fuel gas supply pipe 202 in the fuel gas exhaust pipe 201.

  On the other hand, the end of the cylindrical oxidant gas exhaust pipe 203 is fixed to the other surface of the electrolyte layer 101 so as to surround the region where the air electrode 104 is disposed, and the inner side of the oxidant gas exhaust pipe 203 is fixed. In addition, an oxidant gas supply pipe 204 is disposed. The oxidant gas (oxygen gas) introduced through the oxidant gas supply pipe 204 is supplied to the region of the air electrode 104 from the discharge end of the oxidant gas supply pipe 204. Further, the gas discharged from the air electrode 104 is taken out from a region outside the oxidant gas supply pipe 204 in the oxidant gas discharge pipe 203. Each exhaust pipe is bonded and fixed to the surface of the electrolyte layer 101 by a gas seal 207.

  Next, the measurement results of the air electrode interface resistance of the sample cell and each sample cell will be described. First, it shows in the following Table 1 about the case where LNF is used for an air electrode. When a fuel cell similar to FIG. 2 is assembled using each sample cell created under each condition shown in Table 1 and a power generation test is performed at 700 ° C., a value of 1.14 V is obtained between the platinum terminal 205 and the platinum terminal 206. can get. In addition, room temperature humidified hydrogen is used as the fuel gas, and oxygen is used as the oxidant gas. Further, the voltage response between the air electrode 104 and the reference electrode 107 is measured with an impedance meter in the state where an alternating current is passed between the fuel electrode 102 and the air electrode 104 using the platinum terminal 205 and the platinum terminal 206. Thus, the interface resistance component on the air electrode side is obtained separately. In the “impregnation step”, the “air electrode coating film” is after the step of applying the slurry onto the ceria sintered body layer 113 by screen printing and drying to form a state where the air electrode coating film is formed. The process before baking is shown.

Table 1
Sample number Ceria sintered body layer Metal solution Impregnation process Air electrode interface resistance
1-0 No intermediate layer None None 200Ω
1-1-0 YDC None None 120Ω
1-1-1 YDC La, Ni, Fe Before air electrode formation 67Ω
1-1-2 YDC La, Ni, Fe Air electrode coating film 64Ω
1-1-3 YDC La, Ni, Fe 27Ω after forming air electrode
1-2-1 YDC66% + LNF34% La, Ni, Fe 42Ω before air electrode formation
1-3-1 YDC50% + LNF50% La, Ni, Fe Before air electrode formation 33Ω
1-4-1 YDC34% + LNF66% La, Ni, Fe 51Ω before air electrode formation
1-2-2 YDC66% + LNF34% La, Ni, Fe Air electrode coating film 38Ω
1-3-2 YDC50% + LNF50% La, Ni, Fe Air electrode coating film 30Ω
1-4-2 YDC34% + LNF66% La, Ni, Fe Air electrode coating film 46Ω
1-2-3 YDC66% + LNF34% La, Ni, Fe 20Ω after forming air electrode
1-3-3 YDC50% + LNF50% La, Ni, Fe 12Ω after air electrode formation
1-4-3 YDC34% + LNF66% La, Ni, Fe 23Ω after air electrode formation

  As is clear from Table 1 above, the provision of the intermediate layer reduces the air electrode interface resistance from 200Ω to 120Ω, but sample numbers 1-1-1, 1-1-2, and 1-1-3. From these measurement results, it can be seen that the use of an intermediate layer impregnated with a metal solution and fired further reduces the air electrode interface resistance. By using an intermediate layer impregnated with a metal solution and fired, the intermediate layer in a state where a larger number of oxygen ion conduction paths are formed reduces the air electrode interface resistance. I can see that

  Also, sample numbers 1-2-1, 1-2-1, 1-4-1, 1-2-2, 1-2-2, 1-4-2, 1-2-3, 1-2 From the measurement results of 3 and 1-4-3, it can be seen that the air electrode interface resistance is further lowered when LNF is mixed in the intermediate layer. In particular, when YDC and LNF are mixed at a ratio of 1: 1, the air electrode interface resistance is further reduced. From these, it can be seen that the three-phase interface length is increased. Note that the step of impregnating the metal solution is performed after the air electrode is formed by firing, and the air electrode interface resistance is further reduced.

  Next, Table 2 below shows the case where the ceria sintered body layer is composed of SDC, impregnated with a metal solution in which La ions, Sr ions, and iron ions are dissolved, and LSF is used for the air electrode. The production and measurement method of the fuel cell are the same as in Table 1 above.

Table 2
Sample number Ceria sintered body layer Metal solution Impregnation process Air electrode interface resistance
2-0 No intermediate layer None None 170Ω
2-1-0 SDC None None 121Ω
2-1-1 SDC La, Sr, Fe 62Ω before air electrode formation
2-1-2 SDC La, Sr, Fe Air electrode coating film 58Ω
2-1-3 SDC La, Sr, Fe 32Ω after air electrode formation
2-2-1 SDC66% + LSF34% La, Sr, Fe 48Ω before air electrode formation
2-3-1 SDC50% + LSF50% La, Sr, Fe 44Ω before air electrode formation
2-4-1 SDC34% + LSF66% La, Sr, Fe 58Ω before air electrode formation
2-2-2 SDC66% + LSF34% La, Sr, Fe Air electrode coating film 47Ω
2-3-2 SDC50% + LSF50% La, Sr, Fe Air electrode coating film 45Ω
2-4-2 SDC34% + LSF66% La, Sr, Fe Air electrode coating film 50Ω
2-2-3 SDC66% + LSF34% La, Sr, Fe 32Ω after air electrode formation
2-3-3 SDC50% + LSF50% La, Sr, Fe After forming air electrode 23Ω
2-4-3 SDC34% + LSF66% La, Sr, Fe 39Ω after forming air electrode

  The results are the same as the results shown in Table 1, and the use of the intermediate layer impregnated with a metal solution and firing makes the air electrode interface resistance lower and the intermediate layer is mixed with LSF. When the electrode interface resistance is further decreased and the step of impregnating the metal solution is performed after the air electrode is formed by firing, the air electrode interface resistance is further decreased.

  Next, Table 3 below shows the case where the ceria sintered body layer is composed of YDC, impregnated with a metal solution in which La ions and Co ions are dissolved, and LNF is used for the air electrode. The production and measurement method of the fuel cell are the same as those in Tables 1 and 2 described above.

Table 3
Sample number Ceria sintered body layer Metal solution Impregnation process Air electrode interface resistance
3-1-1 YDC La, Co 54Ω before air electrode formation
3-1-2 YDC La, Co Air electrode coating film 51Ω
3-1-3 20Ω after forming YDC La, Co air electrode
3-2-1 YDC66% + LNF34% La, Co 31Ω before air electrode formation
3-3-1 YDC50% + LNF50% La, Co 27Ω before air electrode formation
3-4-1 YDC34% + LNF66% La, Co 38Ω before air electrode formation
3-2-2 YDC66% + LNF34% La, Co Air electrode coating film 27Ω
3-3-2 YDC50% + LNF50% La, Co Air electrode coating film 25Ω
3-4-2 YDC34% + LNF66% La, Co Air electrode coating film 32Ω
3-2-3 YDC66% + LNF34% La, Co 15Ω after air electrode formation
3-3-3 YDC50% + LNF50% La, Co 14Ω after air electrode formation
3-4-3 YDC34% + LNF66% La, Co 18Ω after air electrode formation

  These are the same as the results shown in Table 1, and when the intermediate layer impregnated with a metal solution and baked is used, the air electrode interface resistance is further reduced, and the intermediate layer is mixed with LNF. However, when the air electrode interface resistance is further lowered and the step of impregnating the metal solution is performed after the air electrode is formed by firing, the air electrode interface resistance is further reduced.

  Next, Table 4 below shows the case where the ceria sintered body layer is made of GDC, impregnated with a metal solution in which La ions, Sr ions, and Co ions are dissolved and LNF is used for the air electrode. The production and measurement method of the fuel cell are the same as those in Table 1, Table 2, and Table 3 described above.

Table 4
Sample number Ceria sintered body layer Metal solution Impregnation process Air electrode interface resistance
4-1-1 GDC La, Sr, Co Before formation of air electrode 49Ω
4-1-2 GDC La, Sr, Co Air electrode coating film 45Ω
4-1-3 GDC La, Sr, Co After air electrode formation 17Ω
4-2-1 GDC66% + LNF34% La, Sr, Co 28Ω before air electrode formation
4-3-1 GDC50% + LNF50% La, Sr, Co 24Ω before air electrode formation
4-4-1 GDC34% + LNF66% La, Sr, Co 36Ω before air electrode formation
4-2-2 GDC66% + LNF34% La, Sr, Co Air electrode coating film 23Ω
4-3-2 GDC50% + LNF50% La, Sr, Co Air electrode coating film 22Ω
4-4-2 GDC34% + LNF66% La, Sr, Co Air electrode coating film 27Ω
4-2-3 GDC66% + LNF34% La, Sr, Co 13Ω after forming air electrode
4-3-3 GDC50% + LNF50% La, Sr, Co 11Ω after forming air electrode
4-4-3 GDC34% + LNF66% La, Sr, Co 15Ω after air electrode formation

  These are the same as the results shown in Table 1, and when the intermediate layer impregnated with a metal solution and baked is used, the air electrode interface resistance is further reduced, and the intermediate layer is mixed with LNF. However, when the air electrode interface resistance is further lowered and the step of impregnating the metal solution is performed after the air electrode is formed by firing, the air electrode interface resistance is further reduced.

It is process drawing which shows the example of a manufacturing method of the solid oxide fuel cell in embodiment of this invention. It is sectional drawing which shows the structural example of a solid oxide fuel cell. FIG. 3 is a perspective view showing a partial configuration of the solid oxide fuel cell shown in FIG. 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Electrolyte layer, 102 ... Fuel electrode, 103 ... Intermediate | middle layer, 104 ... Air electrode, 113 ... Ceria sintered compact layer.

Claims (11)

A step of forming a fuel electrode on one surface of an electrolyte layer made of a sintered metal oxide powder;
A step of forming a porous ceria sintered body layer composed of a sintered body of a powder of cerium oxide doped with a metal oxide on the other surface of the electrolyte layer;
Impregnating the ceria sintered body layer with a metal solution in which ions of a metal constituting the perovskite oxide are dissolved;
After the ceria sintered body layer is formed, applying a slurry in which perovskite oxide powder is dispersed on the other surface of the electrolyte layer to form an air electrode coating film; and ,
Baking the air electrode coating film to form an air electrode; and
By firing the ceria sintered body layer impregnated with the metal solution in an oxygen-containing atmosphere, metal oxide crystal grains containing at least lanthanum are precipitated in the porous pores of the ceria sintered body layer. The intermediate layer formed at least on the other surface of the electrolyte layer,
The method for manufacturing a solid oxide fuel cell, wherein the intermediate layer is formed between the electrolyte layer and the air electrode. In the manufacturing method of the solid oxide fuel cell of Claim 1,
The method for producing a solid oxide fuel cell, wherein the cerium oxide powder is doped with at least one of yttrium oxide, samarium oxide, and gadolinium oxide. In the manufacturing method of the solid oxide fuel cell of Claim 1 or 2,
The metal solution is
Lanthanum ions, nickel ions and iron ions dissolved,
Lanthanum ions, strontium ions and iron ions dissolved,
Lanthanum ions and cobalt ions dissolved,
And at least one of lanthanum ions, cobalt ions, and strontium ions dissolved therein. In the manufacturing method of the solid oxide fuel cell of any one of Claims 1-3,
The ceria sintered body layer is formed from a sintered body obtained by adding a metal oxide powder containing lanthanum for forming the air electrode to a cerium oxide powder doped with a metal oxide. A method for producing a solid oxide fuel cell. In the manufacturing method of the solid oxide fuel cell of any one of Claims 1-4,
The method for producing a solid oxide fuel cell, wherein the step of impregnating the ceria sintered body layer with a metal solution in which the metal ions are dissolved is performed before the air electrode coating film is formed. In the manufacturing method of the solid oxide fuel cell of any one of Claims 1-4,
The method for manufacturing a solid oxide fuel cell, wherein the step of impregnating the ceria sintered body layer with a metal solution in which the metal ions are dissolved is performed after the air electrode coating film is formed. In the manufacturing method of the solid oxide fuel cell of any one of Claims 1-4,
The method for producing a solid oxide fuel cell, wherein the step of impregnating the ceria sintered body layer with a metal solution in which the metal ions are dissolved is performed after the air electrode is formed. An electrolyte layer made of a sintered metal oxide powder;
A fuel electrode formed on one surface of the electrolyte layer;
An intermediate layer formed on the other surface of the electrolyte layer;
An air electrode formed on the intermediate layer and made of a sintered body of perovskite oxide,
The intermediate layer is a metal in which metal ions constituting the perovskite oxide are dissolved in a porous ceria sintered body layer composed of a sintered body of a cerium oxide powder doped with a metal oxide. It is formed by impregnating a solution and firing the ceria sintered body layer impregnated with the metal solution, and the perovskite oxide crystal grains made of the metal ions are porous pores of the ceria sintered body layer. A solid oxide fuel cell characterized by being deposited inside. The solid oxide fuel cell according to claim 8, wherein
The solid oxide fuel cell, wherein the cerium oxide powder is doped with at least one of yttrium oxide, samarium oxide, and gadolinium oxide. The solid oxide fuel cell according to claim 8 or 9,
The metal solution is
Lanthanum ions, nickel ions and iron ions dissolved,
Lanthanum ions, strontium ions and iron ions dissolved,
Lanthanum ions and cobalt ions dissolved,
And a lanthanum ion, a cobalt ion, and a strontium ion dissolved therein. The solid oxide fuel cell according to any one of claims 8 to 10,
The ceria sintered body layer is a sintered body obtained by adding a metal oxide powder containing lanthanum for forming the air electrode to a cerium oxide powder doped with a metal oxide. Solid oxide fuel cell.

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