JP5133787B2 - Solid oxide fuel cell - Google Patents

Description

  The present invention relates to a solid oxide fuel cell using an air electrode comprising a perovskite-type metal oxide and a cerium oxide to which a rare earth is added.

  There is a growing interest in solid oxide fuel cells using zirconia-based oxygen ion conductors, which are excellent electrolyte materials. In particular, from the viewpoint of effective use of energy, solid fuel cells have essentially high energy conversion efficiency because they are not restricted by Carnot efficiency, and have excellent features such as good environmental conservation. have.

  The solid oxide fuel cell initially had a high operating temperature of 900 to 1000 ° C., and all members were made of ceramic. For this reason, it was not easy to reduce the manufacturing cost of the cell stack. Here, if the operating temperature can be lowered to 800 ° C. or less, a heat-resistant alloy material can be used for the interconnector, and the manufacturing cost can be reduced. However, as the operating temperature decreases, the electrochemical resistance at the air electrode, that is, the overvoltage, suddenly increases and the output voltage decreases.

In order to solve the problem of the air electrode due to such a decrease in operating temperature, La _1-X Sr _X Fe _1-Y Co _Y O ₃ (LSFC: X = 0.1 to 0.3, Y = 0.1 ~0.6, X + Y <0.7) , La 1-X Sr X CoO 3 (X = 0.1~0.5), LaNi 1-X Fe X O 3 (LNF: X = 0.3~0 There is a technique using a perovskite-type metal oxide (perovskite oxide) having high electrode activity (electrochemical reaction performance) such as .8). These materials are perovskite oxides containing La and Sr at the A site and Ni, Co, and Fe at the B site. Some A sites contain La and Ca. These materials are suitable for an air electrode for low temperature operation.

However, since the air electrode is manufactured by firing in contact with an electrolyte containing zirconia, an insulator such as La ₂ Zr ₂ O ₇ is generated in a portion in contact with the electrolyte, and this product is This is one of the causes of deteriorating characteristics in the air electrode. In order to prevent this problem, Ce ₀ . ₉ Gd ₀ . ₁ O ₂ and Ce ₀ . ₈ Sm ₀ . _A method of providing a ceria layer made of cerium oxide (ceria compound) doped with rare earth such as ₂ O ₂ and cutting the contact between the perovskite oxide on the air electrode side and zirconia on the electrolyte side has been studied (non-patented) Reference 1). The ceria layer thus provided has high oxygen ion conductivity, and a reaction that generates an insulator with the perovskite oxide is less likely to occur.

Further, in order to further improve the low temperature characteristics of a solid oxide fuel cell using an air electrode composed of the above-described materials, a method of providing a mixture of perovskite oxide particles and a ceria compound in the vicinity of an electrolyte is known. (See Non-Patent Document 2). By forming the air electrode in a state where the perovskite oxide powder (powder) and the fine powder of the ceria compound are mixed, the active area of the electrode generated at the joint between the electrolyte and the air electrode is increased. Interfacial resistance can be reduced. The ceria compound is suitable as a material to be mixed with the air electrode because the reaction deterioration with the Co-based and Fe-based air electrode materials described above hardly occurs. In the air electrode made of this mixture, the perovskite oxide particles are arranged to be covered with ceria compound particles, and the direct contact between the zirconia-based material portion constituting the electrolyte and the perovskite oxide material is suppressed, Production of reaction products with harmful zirconia such as La ₂ Zr ₂ O ₇ is suppressed.

A. Mai, et al., "Ferrite-based perovskites as cathode materials for anode-suported solid oxide fuel cells Part II influence of the CGO recycling", Solid State Ionics 177, pp.2103-2107, 2006. Y. Matsuzaki, et al., "Electrochemical properties of reduced-temperature SOFCs with mixed ionic-electronic conductors in electrodes and / or connecteds", Solid State Ionics 152-153, pp.463-468, 2002. Hiroaki Tagawa, Solid oxide fuel cell and global environment, Agne Jofusha Co., Ltd., 1st edition, 1st edition, 1998.

  As described above, by producing an air electrode using a ceria compound, the problem of the air electrode due to a decrease in operating temperature, such as a decrease in output voltage due to an increase in electrochemical resistance in the air electrode, is solved. However, further improvement of the output voltage at the air electrode has been demanded.

  The present invention has been made to solve the above-described problems. By improving the characteristics of the air electrode including the ceria compound, the output voltage of the solid oxide fuel cell can be further increased. The objective is to improve.

The solid oxide fuel cell according to the present invention is a solid oxide fuel cell including a fuel electrode, an electrolyte, and an air electrode. The air electrode is (PrO _11/6 ) _1-xy (CeO ₂ ) _x (RO _3/2 ) _y (0.3 <x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ x + y ≦ 0.98, R = Y, Nd, La, Sm, Gd) .

In the solid oxide fuel cell, the air electrode is composed of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y in addition to a perovskite-type metal oxide. May be. In this case, the air electrode is a mixture of a _first powder made of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y and a second powder made of a perovskite-type metal oxide. What is necessary is just to comprise from the sintered compact of the mixed powder made. The air electrode is disposed on the electrolyte side, and includes a first layer composed of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y and the first layer. And a second layer composed of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y in addition to a perovskite-type metal oxide. It may be.

  The solid oxide fuel cell may include an intermediate layer that is disposed between the electrolyte and the air electrode and is made of cerium oxide to which a rare earth other than praseodymium is added. Moreover, you may make it provide the current collection layer which is arrange | positioned on the opposite side to the electrolyte of an air electrode, and was comprised from the perovskite type metal oxide.

As described above, according to the present invention, the air electrode is (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ 1-xy <0.7, R = Y, Nd, La, Sm, Gd), so that the air electrode is composed of the ceria compound and the perovskite oxide. In the solid oxide fuel cell, an excellent effect is obtained in that further improvement in output voltage can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
First, Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view schematically showing a configuration example of a solid oxide fuel cell according to Embodiment 1 of the present invention. This solid oxide fuel cell includes an electrolyte 101 made of a zirconia-based material and a fuel electrode 102 formed on one surface of the electrolyte 101. In addition, the solid oxide fuel cell of the present embodiment is formed on the other side of the electrolyte 101, and (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ 1-xy <0.7). R is a rare earth element selected from yttrium (Y), neodymium (Nd), lanthanum (La), samarium (Sm), and gadolinium (Gd).

The electrolyte 101 may be, for example, scandium oxide (Sc ₂ O ₃ ) and aluminum oxide (Al ₂ O ₃ ) stabilized ZrO ₂ (SASZ), yttria stabilized zirconia (YSZ), scandia stabilized zirconia (ScSZ), etc. What is necessary is just to be comprised from the sintered compact of the powder (powder) of the zirconia material. The fuel electrode 102 is made of, for example, nickel-yttria stabilized zirconia cermet (Ni-YSZ), nickel-scandia stabilized zirconia (Ni-ScSZ), and the like, in which metal nickel is mixed with an oxide material constituting the electrolyte 101. It is only necessary to be composed of a sintered body of a powder of a metal-oxide mixture (cermet) having electron conductivity.

  In addition, as is well known, each of these layers produces a slurry of powder or mixed powder, and forms a slurry film (layer) by molding by a doctor blade method or application by a screen printing method, This can be produced by firing at 1000 to 1200 ° C.

  According to the solid oxide fuel cell of the present embodiment configured as described above, in the air electrode 103, the hole conductivity is improved, and the mixed conductor region in which the ion conductivity and the hole conductivity are improved is formed. As a result, the characteristics are improved and the output voltage is improved. In addition, fuel gas containing hydrogen obtained by reforming hydrocarbon gas such as city gas is supplied to the fuel electrode 102, and air containing oxygen as oxidant gas is supplied to the air electrode 103, A power generation operation is performed.

Here, the presence of Pr in the air electrode 103 will be described. According to the present embodiment, since Pr is contained, the field where oxygen gas in the air is used as oxygen ions is increased, and the reaction field (three-phase interface) of the electrochemical reaction at the air electrode is wider. It is thought that it will be in a state expanded to. As a result, (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ 1-xy <0 .7), it is considered that the characteristics of the air electrode 103 are improved and the output voltage is further improved.

Here, generally, the solid solubility limit of Pr with respect to the ceria compound is set to about 30 at%, and in the state where the amount of Pr added to the ceria compound exceeds 30 at%, it is said that better characteristics cannot be obtained. . On the other hand, in the present invention, it has been found that better air electrode characteristics can be obtained by adding Pr exceeding 30 at% to the ceria compound. In other words, in the present invention, the air electrode 103 is formed by adding Pr to an air electrode material that includes a cerium oxide to which a rare earth is added, and the amount of Pr added to the cerium oxide is 0. The characteristic is that the amount exceeds 3. As will be described later, a perovskite-type metal oxide may be mixed with (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y to form an air electrode.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view schematically showing a configuration example of the solid oxide fuel cell according to Embodiment 2 of the present invention. This solid oxide fuel cell includes an electrolyte 101, a fuel electrode 102 formed on one surface of the electrolyte 101, and an air electrode 103 formed on the other side of the electrolyte 101. In the present embodiment, the air electrode 103 is disposed on the electrolyte 101 side, and (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1,0) ≦ y ≦ 0.4, 0 ≦ 1-xy <0.7, R = Y, Nd, La, Sm, Gd), and a buffer layer (first layer) 103a and a buffer layer 103a An electrode layer (second layer) which is arranged in contact with each other and is composed of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y in addition to a perovskite-type metal oxide 103b.

  Note that the solid oxide fuel cell according to the present embodiment includes a current collecting layer 201 that is arranged on the opposite side of the air electrode 103 from the electrolyte 101 and is made of a perovskite metal oxide, in addition to the above-described configuration. . In this case, the electrolyte 101 is arranged on one side of the air electrode 103, and the current collecting layer 201 is arranged on the other side of the air electrode 103, and the air electrode 103 is sandwiched between the electrolyte 101 and the current collecting layer 201. Become.

  As is well known, in a solid oxide fuel cell, a plurality of single cells composed of an electrolyte 101, a fuel electrode 102, and an air electrode 103 are stacked through an interconnector to generate a practical voltage. It is configured to take out. Thus, when it is set as a laminated | stacked (stack) structure, in order to obtain the favorable electrical connection between the fuel electrode 102 and the air electrode 103, and each interconnector, it is good to use a collector. For example, a current collector made of Ni mesh may be used between the fuel electrode 102 and the interconnector. Further, a current collector made of a heat-resistant alloy mesh may be used between the air electrode 103 and the interconnector. Further, the air electrode 103 and the interconnector may be connected by applying and baking a conductive metal oxide paste.

  In the present embodiment, since the current collecting layer 201 made of perovskite oxide, which is an electron conductor (hole conductor), is provided on the air electrode 103 side, it is connected to the air electrode 103. A better electrical connection with the interconnector can be obtained. It can be considered that the entire air electrode 103 including the current collecting layer 201 functions as an air electrode.

[Embodiment 3]
Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view schematically showing a configuration example of the solid oxide fuel cell according to Embodiment 3 of the present invention. This solid oxide fuel cell includes an electrolyte 101, a fuel electrode 102 formed on one surface of the electrolyte 101, and an air electrode 103 formed on the other side of the electrolyte 101. The air electrode 103 includes a buffer layer 103a and an electrode layer 103b. The solid oxide fuel cell includes a current collecting layer 201. These are the same as those of the solid oxide fuel cell of Embodiment 2 described above.

In the present embodiment, in addition to the above-described configuration, an intermediate layer 301 is provided that is disposed between the electrolyte 101 and the air electrode 103 and is composed of cerium oxide to which a rare earth other than Pr is added. is there. For example, the intermediate layer _{301, GDC (Ce 0. 9 Gd} 0. 1 O) a may be composed of a sintered body of a powder. By providing the intermediate layer 301 in this way, zirconia constituting the electrolyte 101 and La and Pr constituting the air electrode 103 can be more efficiently separated, and a solid oxide fuel cell (air electrode) / Electrolyte) interface resistance can be further suppressed. In addition, it can also be considered that the entire air electrode 103 including the intermediate layer 301 functions as an air electrode.

  Next, the characteristic measurement result in the single cell of the actually produced solid oxide fuel cell will be described below.

[Measuring method]
First, measurement will be described. As will be described later, in each of the fabricated sample cells, the interfacial resistance, which is an index of electrode performance, is measured by an AC impedance method. At the time of measurement, it is performed under the condition of an open circuit voltage, a minute AC signal is applied between the air electrode and the fuel electrode, and a minute electric potential change between the air electrode and the reference electrode (fuel electrode) is measured. The impedance is obtained from the result. In the measurement, humidified hydrogen gas at room temperature (about 23 ° C.) was supplied as fuel gas to the fuel electrode, and oxygen was supplied to the air electrode. Moreover, as an open electromotive force, the value of 1.13V or more is obtained at 800 degreeC.

[Production of cell]
Next, production of a single cell of a solid oxide fuel cell serving as a sample will be described. First, well known Sc ₂ O ₃ obtained by firing molded into a sheet by a doctor blade method, Al ₂ O ₃ doped zirconia _{(0.89ZrO 2 -0.10Sc 2 O 3 -0.01Al} 2 O 3: SASZ An electrolyte substrate is prepared. The electrolyte substrate is formed to a thickness of 0.2 mm. Next, a mixture of zirconia powder (40 wt%) with an average particle diameter of about 0.3 μm added with 8 mol% Y ₂ O ₃ and NiO powder (60 wt%) with an average particle diameter of 0.8 μm was mixed. A slurry of powder is prepared, and this slurry is applied to one surface of the above-described electrolyte substrate by a well-known screen printing method (see Non-Patent Document 3) to form a fuel electrode coating film. In addition, a current collector made of platinum mesh is disposed on the fuel electrode coating film, and these are fired in air under a heat treatment condition of 1400 ° C. for 4 hours. It is assumed that a fuel electrode having a thickness of 60 μm is formed.

  Next, a slurry of GDC powder having an average particle size of 0.2 μm is prepared, and this slurry is applied to the other surface of the above-described electrolyte substrate by a screen printing method to form an intermediate layer coating film. This is fired under heat treatment conditions of 1200 ° C. to form an intermediate layer having a thickness of 4 μm. This is an intermediate layer made of cerium oxide (GDC) to which a rare earth other than Pr is added.

Next, a slurry of (PrO _11/6 ) _1-xy (CeO ₂ ) _x (RO _3/2 ) _y powder having an average particle size of 0.2 μm was prepared, and this slurry was used as the other electrolyte substrate described above. The air electrode coating film is formed on the surface of the film by screen printing. Next, the electrolyte substrate on which the air electrode coating film is formed is baked under heat treatment conditions of 1000 ° C. for 2 hours to form a state in which an air electrode having a thickness of 4 μm made of a sintered body of the powder is formed.

Next, LaNi ₀ . ₆ Fe ₀ . A slurry of ₄ O ₃ (LNF) powder is prepared, and this slurry is applied on the air electrode by the screen printing method to form a current collecting layer coating film. Thereafter, the electrolyte substrate on which the current collector layer coating film is formed is fired under heat treatment conditions of 1150 ° C. for 2 hours, and a current collector having a thickness of 40 μm made of a sintered body of LNF powder is formed on the air electrode. A layer is formed. Finally, a Pt mesh current collector is placed on the current collecting layer and fired under heat treatment conditions of 1000 ° C. for 2 hours.

  As shown in the perspective view of FIG. 4, the single cell formed in this way is formed on a disk 10 mm in diameter on an electrolyte substrate 401 formed in a square plate shape with a side of 30 mm. Has been placed. In FIG. 4, the fuel electrode disposed below the electrolyte substrate 401 is omitted from illustration. In addition, this single cell includes the reference electrode 403 made of platinum around the electrolyte substrate 401, and performs the above-described measurement in a state where it is connected thereto.

[Example 1]
Next, as Example 1, solid oxide fuel cells (sample cells: # 1-1 to # 1-10, # 1-11 to # 1-20, # 1-21 to # 1- 30, # 1-31 to # 1-40, # 1-41 to # 1-50) will be described. This sample cell is obtained by changing the composition ratio of Pr in (PrO _11/6 ) _1-xy (CeO ₂ ) _x (RO _3/2 ) _y used for producing the air electrode of the sample cell described above. The composition ratio is indicated by the ratio of PrO _11/6 , CeO ₂ and RO _3/2 .

Here, the sample cells (# 1-1 to # 1-10) have R as Gd (PGDC), and the sample cells (# 1-11 to # 1-20) have R as Sm. (PSDC), sample cells (# 1-21 to # 1-30) are R (YY) (PYDC), and sample cells (# 1-31 to # 1-40) are R Is La (PLDC), and the sample cells (# 1-41 to # 1-50) are Rd (PNDC). From the electrolyte side, the single cell of Example 1 is “an intermediate layer made of GDC / an air electrode made of (PrO _11/6 ) _1-xy (CeO ₂ ) _x (RO _3/2 ) _y / an LNF collection. It has a “electric layer” configuration. The comparative sample cell (# 1-0) for comparison is a result when GDC not added with Pr is used for the air electrode.

  When the measurement described above was performed in these sample cells, as shown in Table 1-1, Table 1-2, Table 1-3, Table 1-4, and Table 1-5, comparative samples were used. Compared with the cell (# 1-0), any sample cell (# 1-1 to # 1-10, # 1-11 to # 1-20, # 1-21 to # 1-30, # 1- 31- # 1-40, # 1-41- # 1-50) also show good results with low interface resistance.

[Example 2]
Next, production of a solid oxide fuel cell (sample cell: # 2-1 to # 2-10) serving as a sample will be described as Example 2. In this sample cell, the air electrode of the above-described comparative sample cell is replaced with (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0). .4, 0 ≦ 1-xy <0.7, R = Gd) and a perovskite-type metal oxide. For example, a mixed powder in which a first powder made of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y and a second powder made of a perovskite-type metal oxide are mixed. Then, this slurry is applied to the other surface of the electrolyte substrate by a screen printing method to form an air electrode coating film. Next, if the electrolyte substrate on which the air electrode coating film is formed is baked under heat treatment conditions of 1000 ° C. for 2 hours, an air electrode having a thickness of 4 μm made of a sintered body of the mixed powder is formed. In Example 2, LNF is used as the perovskite-type metal oxide to be mixed.

From the electrolyte side, the single cell of Example 2 is “an intermediate layer made of GDC / (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y mixed with LNF in an air electrode / LNF. It has a structure of “current collecting layer consisting of”. As a comparative sample cell (# 2-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the above-described measurement is performed in these sample cells, as shown in Table 2-1 below, any sample cell (# 2-1 to # 2) is compared with the comparative sample cell (# 2-0). -10), good results were obtained with low interface resistance.

[Example 3]
Next, as Example 3, the production of solid oxide fuel cells (sample cells: # 3-1 to # 3-10) to be samples will be described. This sample cell has (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ _1-xy ) <0.7, R = Gd) and a buffer layer arranged in contact with the buffer layer, in addition to (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y and perovskite An air electrode is composed of an electrode layer composed of mixed metal oxides.

From the electrolyte side, the single cell of Example 3 is “GDC intermediate layer / (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y buffer layer / (PrO _{11 / 6} ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y electrode layer / mixing layer made of LNF mixed with LNF ”. As a comparative sample cell (# 3-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the above-described measurement is performed in these sample cells, as shown in Table 3-1 below, any sample cell (# 3-1 to # 3) is compared with the comparative sample cell (# 3-0). -10), good results were obtained with low interface resistance.

[Example 4]
Next, as Example 4, the production of a solid oxide fuel cell (sample cell: # 4-1 to # 4-10) serving as a sample will be described. In this sample cell, La _0.7 Sr _0.3 Fe _0.7 Co _0.3 O ₃ (LSFC) is used instead of the current collecting layer in Example 1 described above. However, (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ 1-xy <0. 7, R = Gd) to form the air electrode.

From the electrolyte side, the single cell of Example 4 is “an intermediate layer made of GDC / air electrode made of (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y / collected of LSFC. It has a “electric layer” configuration. Also in this embodiment, an intermediate layer made of GDC is provided on the electrolyte layer side. As a comparative sample cell (# 4-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the above-described measurement is performed in these sample cells, as shown in the following Table-4-1, any sample cell (# 4-1 to # 4) is compared with the comparative sample cell (# 4-0). -10), good results were obtained with low interface resistance.

[Example 5]
Next, as Example 5, production of a solid oxide fuel cell (sample cell: # 5-1 to # 5-10) serving as a sample will be described. In this sample cell, La _0.8 Sr _0.2 CoO ₃ (LSC) is used instead of the current collecting layer in Example 1 described above instead of LNF. However, (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ 1-xy <0. 7, R = Gd) to form the air electrode.

From the electrolyte side, the single cell of Example 5 is “an intermediate layer made of GDC / air electrode made of (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y / LSC made of LSC. It has a “electric layer” configuration. As a comparative sample cell (# 5-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the above-described measurement is performed in these sample cells, as shown in Table-5-1 below, any sample cell (# 5-1 to # 5) is compared with the comparative sample cell (# 5-0). -10), good results were obtained with low interface resistance.

[Example 6]
Next, as Example 6, production of a solid oxide fuel cell (sample cell: # 6-1 to # 6-10) serving as a sample will be described. In this sample cell, LaCoO ₃ (LC) is used instead of the current collecting layer in Example 1 described above instead of LNF. However, (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ 1-xy <0. 7, R = Gd) to form the air electrode.

From the electrolyte side, the single cell of Example 6 is “an intermediate layer made of GDC / an air electrode made of LC / (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y / LC”. It has a “electric layer” configuration. As a comparative sample cell (# 6-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the above-described measurement is performed in these sample cells, as shown in Table-6-1 below, any sample cell (# 6-1 to # 6) is compared with the comparative sample cell (# 6-0). -10), good results were obtained with low interface resistance.

[Example 7]
Next, as Example 7, the production of a solid oxide fuel cell (sample cell: # 7-1 to # 7-10) serving as a sample will be described. In this sample cell, La _0.8 Sr _0.2 MnO ₃ (LSM) is used instead of the current collecting layer in Example 1 described above instead of LNF. However, (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ 1-xy <0. 7, R = Gd) to form the air electrode.

From the electrolyte side, the single cell of Example 7 is “GDC intermediate layer / (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y air electrode / LSM It has a “electric layer” configuration. Also in this embodiment, an intermediate layer made of GDC is provided on the electrolyte layer side. As a comparative sample cell (# 7-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the above-described measurement is performed on these sample cells, as shown in Table 7-1 below, any sample cell (# 7-1 to # 7) is compared with the comparative sample cell (# 7-0). -10), good results were obtained with low interface resistance.

[Example 8]
Next, as Example 8, the production of solid oxide fuel cells (sample cells: # 8-1 to # 8-10) to be samples will be described. This sample cell is obtained by replacing the LNF used for the air electrode and the current collecting layer in Example 2 described above with LSFC, and the other configurations are the same as in Example 2.

From the electrolyte side, the unit cell of Example 8 is “an intermediate layer made of GDC / (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y mixed with LSFC and cathode / LSFC. It has a structure of “current collecting layer consisting of”. As a comparative sample cell (# 8-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the above-described measurement is performed in these sample cells, as shown in Table-8-1 below, any sample cell (# 8-1 to # 8) is compared with the comparative sample cell (# 8-0). -10), good results were obtained with low interface resistance.

[Example 9]
Next, as Example 9, the production of a solid oxide fuel cell (sample cell: # 9-1 to # 9-10) serving as a sample will be described. This sample cell is obtained by replacing the LNF used for the air electrode and the current collecting layer in Example 2 described above with LSC, and other configurations are the same as in Example 2. From the electrolyte side, the unit cell of Example 9 is “an intermediate layer made of GDC / (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y mixed with LSC and cathode / LSC. It has a structure of “current collecting layer consisting of”. As a comparative sample cell (# 9-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the measurement described above was performed in these sample cells, as shown in Table-9-1 below, any sample cell (# 9-1 to # 9) was compared with the comparative sample cell (# 9-0). -10), good results were obtained with low interface resistance.

[Example 10]
Next, as Example 10, the production of a solid oxide fuel cell (sample cell: # 10-1 to # 10-10) serving as a sample will be described. In this sample cell, LNF used for the electrode layer and the current collecting layer in Example 3 described above was replaced with LSFC, and the other configurations were the same as in Example 3.

From the electrolyte side, the single cell of Example 10 has an “intermediate layer made of GDC / buffer layer made of (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y / (PrO _{11 / 6} ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y electrode layer obtained by mixing LSFC / current collecting layer comprising LSFC ”. As a comparative sample cell (# 10-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the above-described measurement is performed in these sample cells, as shown in Table-10-1, the sample cell (# 10-1 to # 10) is compared with the comparative sample cell (# 10-0). -10), good results were obtained with low interface resistance.

[Example 11]
Next, as Example 11, the production of a solid oxide fuel cell (sample cell: # 11-1 to # 11-10) serving as a sample will be described. This sample cell is obtained by replacing the LNF used for the electrode layer and the current collecting layer in Example 3 described above with LSC, and other configurations are the same as in Example 3. From the electrolyte side, the unit cell of Example 11 was “intermediate layer made of GDC / buffer layer made of (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y / (PrO _{11 / 6} ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y electrode layer / current collector layer composed of LSC mixed with LSC ”. As a comparative sample cell (# 11-0) for these, GDC is used instead of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y .

  When the measurement described above is performed in these sample cells, as shown in Table 11-1 below, any sample cell (# 11-1 to # 11) is compared with the comparative sample cell (# 11-0). -10), good results were obtained with low interface resistance.

[Example 12]
Next, as Example 12, the production of a solid oxide fuel cell (sample cell: # 12-1, # 12-2) as a sample will be described. This sample cell constituted a single cell without using a current collecting layer in Example 2 and Example 8 mentioned above. Other configurations are the same as those in the second and eighth embodiments. The single cell of Example 12 has an “intermediate layer made of GDC / air electrode in which LNF is mixed with (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y ” from the electrolyte side. It has a configuration.

  When the above-described measurement is performed on these sample cells, as shown in the following Table-12-1, even in the sample cells (# 12-1, # 12-2) not provided with the current collecting layer, the interface resistance is low. Low and good results are obtained.

[Example 13]
Next, as Example 13, the production of solid oxide fuel cells (sample cells: # 13-1 to # 13-7) to be samples will be described. This sample cell constituted a single cell without using the intermediate layer of the electrolyte layer in the above-described Example 1, Example 2, Example 4, Example 5, Example 5, Example 6, Example 7, and Example 9. . Other configurations are the same as those of the first embodiment, the second embodiment, the fourth embodiment, the fifth embodiment, the sixth embodiment, the seventh embodiment, and the ninth embodiment, and include a current collecting layer.

The single cell of Example 13 has a current _{collector made of} “(PrO _11/6 ) _1-xy (CeO ₂ ) _x (RO _3/2 ) _y / perovskite type metal oxide from the electrolyte side”. Layer ”or from the electrolyte side,“ (PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y mixed with perovskite metal oxide / air electrode / perovskite metal oxide It has a structure of “current collecting layer consisting of”.

  When the measurement described above is performed in these sample cells, as shown in Table 13-1, the interface resistance is low even in the sample cells (# 13-1 to # 13-7) not provided with the intermediate layer. Good results have been obtained.

[Example 14]
Next, as Example 14, the production of a solid oxide fuel cell (sample cell: # 14-1, # 14-2) as a sample will be described. This sample cell formed a single cell in Example 2 and Example 8 described above without using the intermediate layer and the current collecting layer. Other configurations are the same as those in the second and eighth embodiments. The unit cell of Example 14 has a configuration of “(PrO _11/6 ) _1-xy (CeO ₂ ) _x (GdO _3/2 ) _y mixed with perovskite-type metal oxide from the electrolyte side”. It has become.

  When the above-described measurements were performed on these sample cells, as shown in Table 14-1 below, even in the sample cells (# 14-1, # 14-2) that do not include the intermediate layer and the current collecting layer, The interface resistance is low and good results are obtained.

[Example 15]
Next, as Example 15, the production of a solid oxide fuel cell (sample cell: # 15-1, # 15-2) as a sample will be described. In this sample cell, the air electrode was configured in the same manner as in Example 10 and Example 11 described above, and a single cell was configured without using the intermediate layer and the current collecting layer.

From the electrolyte side, the unit cell of Example 15 is “(CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0. 4, 0 ≦ 1-xy <0.7, R = Gd) / (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y in addition to perovskite Type metal oxide (LC and LSM) mixed electrode layer ”.

  When the measurement described above is performed in these sample cells, as shown in Table 14-1, the air electrode is composed of a buffer layer and an electrode layer in a configuration that does not include an intermediate layer and a current collecting layer. However, good results have been obtained with low interface resistance.

From the above embodiment, the air electrode is (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ 1-xy <0.7, R = Y, Nd, La, Sm, Gd), the characteristics of the air electrode are improved. When the current collecting layer and intermediate layer are not used, perovskite type metal oxide is added to the air electrode in addition to (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y. It is good to have. Thus, if the characteristics of the air electrode are improved, further improvement in output voltage in the solid oxide fuel cell can be obtained.

  In addition, the particle diameter mentioned above is an average particle diameter obtained from the measurement of the light intensity distribution pattern by the well-known laser diffraction scattering method. For example, the particle size can be measured by using a laser diffraction / scattering particle size distribution measuring device LA-910 manufactured by HORIBA, Ltd.

It is sectional drawing which shows typically the structural example of the solid oxide fuel cell in Embodiment 1 of this invention. It is sectional drawing which shows typically the structural example of the solid oxide fuel cell in Embodiment 2 of this invention. It is sectional drawing which shows typically the structural example of the solid oxide fuel cell in Embodiment 3 of this invention. It is a perspective view which shows the structure of a sample cell.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Electrolyte, 102 ... Fuel electrode, 103 ... Air electrode, 103a ... Buffer layer (1st layer), 103b ... Electrode layer (2nd layer), 201 ... Current collection layer, 301 ... Intermediate | middle layer.

Claims (6)

In a solid oxide fuel cell comprising a fuel electrode, an electrolyte, and an air electrode,
The air electrode has (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y (0.02 ≦ x ≦ 1, 0 ≦ y ≦ 0.4, 0 ≦ _1-xy ). <0.7, R = Y, Nd, La, Sm, Gd). The solid oxide fuel cell according to claim 1, wherein
The air electrode is formed by mixing a perovskite-type metal oxide in addition to the (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y. Oxide fuel cell. The solid oxide fuel cell according to claim 2, wherein
In the air electrode, a _first powder made of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y and a second powder made of a perovskite metal oxide are mixed. A solid oxide fuel cell comprising a sintered body of mixed powder. The solid oxide fuel cell according to claim 2 or 3,
The air electrode is
A first layer disposed on the electrolyte side and composed of (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y ;
The first layer is arranged in contact with the first layer, and is formed by mixing a perovskite-type metal oxide in addition to the (CeO ₂ ) _1-xy (PrO _11/6 ) _x (RO _3/2 ) _y . A solid oxide fuel cell comprising: two layers. In the solid oxide fuel cell according to any one of claims 1 to 4,
A solid oxide fuel cell comprising an intermediate layer made of cerium oxide, which is disposed between the electrolyte and the air electrode and to which a rare earth other than praseodymium is added. In the solid oxide fuel cell according to any one of claims 1 to 5,
A solid oxide fuel cell comprising a current collecting layer disposed on the opposite side of the air electrode from the electrolyte and made of the perovskite metal oxide.

Images