JP2009230874A - Structural body for cell, method for manufacturing same and utilization of same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structural body for a single cell of SOFC and a method for manufacturing the same reducing the thickness of the cell while increasing the strength of the cell of the SOFC. <P>SOLUTION: The structural body for the single cell of the solid oxide fuel cell has a laminated structure that two porous ceramics material layers are opposed to each other with a dense ceramics material layer containing an ion oxide conductive ceramics material interposed between them. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cell structure, a method for producing the same, and a use thereof, and more particularly, a structure suitable for a solid oxide fuel cell, and more particularly, a cell structure for a solid oxide fuel cell, The present invention relates to a fuel cell single cell, a solid oxide fuel cell, and a method for producing them. Moreover, this invention relates to the ceramic structure used as the housing of a ceramic device.

  Examples of a device mainly composed of a ceramic material (hereinafter simply referred to as a ceramic device) include a gas sensor such as oxygen, a separation filter, and a solid oxide fuel cell (hereinafter also simply referred to as SOFC). For example, in SOFC, a unit composed of a fuel electrode, a solid electrolyte, and an air electrode is referred to as a single cell, and a series connection is realized by stacking the unit to construct a power generation system. In order to obtain a sufficient amount of power generation, it is necessary to stack several tens to several hundreds of single cells. The strength needs to be high enough. In order to improve the power generation characteristics of the single cell and thus the power generation characteristics of the stack, it is essential to keep the internal resistance of the single cell low.

  As a structure for ensuring the mechanical strength of a single cell, an electrolyte-supported cell and an electrode-supported cell are known. The electrolyte-supported cell has a thickness of a solid electrolyte of several hundred microns or more, and a fuel electrode and an air electrode of several tens of microns are baked on both surfaces of the solid electrolyte. The electrode-supported cell supports the cell by thinning the solid electrolyte with the highest resistance among the cell components and making the air or fuel electrode with a relatively low internal resistance to a thickness of several hundred microns to several millimeters. It is a structure to do.

  For example, as an electrolyte supporting cell, it is disclosed that an oxide ion conductor powder is baked into a porous surface of a dense solid electrolyte layer, and then an electrode material is introduced (Patent Document 1). According to this method, it is described that the peelability between the electrolyte, which is the cause of deterioration, and each electrode layer can be improved.

  As an example of an electrode-supported cell, the solid electrolyte membrane and the skeleton of the air electrode are integrally fired with the same material, then the obtained skeleton is impregnated with the air electrode material and fired, and then the solid electrolyte skeleton is formed. It is disclosed that a fuel electrode material is applied to a surface that is not exposed and fired (Patent Document 2). According to this method, since the contraction process of the solid electrolyte membrane and the air electrode is the same, it is described that strict control of the contraction process is unnecessary.

  As another example of an electrode-supporting cell, a fuel electrode substrate is formed of a green sheet in which a positron substrate having high porosity and continuous pores and a fuel electrode material imparting a skeleton and conductivity, such as zirconia, are deposited. In addition, it is disclosed that an electrolyte is applied to the fuel electrode substrate (green sheet, screen printing) and fired (Patent Document 3). According to this method, it is described that warpage and cracking due to a difference in thermal expansion coefficient between the fuel electrode and the solid electrolyte can be avoided.

JP 2003-263993 A Japanese Patent Laid-Open No. 7-201341 JP 2006-351403 A

  However, in the electrolyte support type cell, the electrolyte has a high resistance and it is difficult to suppress the internal resistance. In addition, the method disclosed in Patent Document 1 can be applied only when a solid electrolyte can serve as a support.

  In the electrode support type cell, since the porous electrode is the support, the electrode itself needs to have a thickness of several hundred μ to several millimeters. Such a thick electrode significantly deteriorates the polarization characteristics. Further, the internal resistance cannot be effectively suppressed. In addition, in the electrode-supported cell, the electrode on one side is used as a support due to a process problem, so the cell warpage occurs due to the difference in shrinkage from the electrolyte, and the composition of each member related to the output characteristics to avoid this. And structure and processes are severely limited.

  In other words, the conventional cell support structure is a major impediment to the improvement of the SOFC characteristics, because there are significant restrictions on securing the strength and process.

  In addition, the above-described problems exist not only in SOFC but also in securing strength of other ceramic devices, thinning and downsizing.

  Accordingly, an object of the present invention is to provide an SOFC cell structure that can easily increase the cell strength of the SOFC and a method for manufacturing the same. Another object of the present invention is to provide a structure for a SOFC cell that can further reduce the thickness of the cell and a method for manufacturing the same. Furthermore, another object of the present invention is to provide an SOFC single cell that can reduce the internal resistance by using such a structure for SOFC cell and a method of manufacturing the same. Another object of the present invention is to provide an SOFC capable of realizing high output and a method for manufacturing the same.

  Another object of the present invention is to provide a ceramic structure that is a structural housing suitable for manufacturing various ceramic devices.

  The inventors of the present invention have noticed that the problem of the conventional cell structure is that a part of the cell is used as a support and the remaining part is attached thereto. That is, in order to adopt such a partial support structure, it is necessary to increase the thickness of some elements as a support, and for the thickness, material composition, shrinkage ratio, etc. of these partial elements We found that there were significant restrictions on the thickness and material composition of other elements. Further, due to such restrictions, it has been found that improvement in gas permeability and reduction in internal resistance, which should originally be provided as SOFC, have not been realized. Thus, the present inventors have found that by providing a novel cell support structure, it is possible to eliminate various obstruction factors for improving the battery characteristics of SOFC caused by the conventional cell support structure, and have completed the present invention. That is, according to the present invention, the following means are provided.

  According to the present invention, there is provided a structure for a single cell of a solid oxide fuel cell comprising a laminated structure in which two porous ceramic material layers are opposed to each other with a dense oxide ion conductive ceramic material layer interposed therebetween. Provided.

  In the single cell structure of the present invention, the dense ceramic material layer may contain two or more kinds of ceramic materials, and the dense ceramic material layer has two or more kinds of ceramic material layers. It may be. The porous ceramic material layer can contain the same ceramic material as the ceramic material contained in the dense ceramic material layer.

  According to the present invention, a method for manufacturing a structure for a single cell of a solid oxide fuel cell, in which two porous ceramics can be formed with a dense ceramic material layer capable of forming a dense ceramic interposed therebetween. A structure for a single cell of a solid oxide fuel cell, comprising: a step of preparing a precursor of a ceramic laminate having a laminated structure facing a porous ceramic raw material layer; and a step of firing the precursor. A manufacturing method is provided.

  In this production method, the porous ceramic material layer can contain a pore-forming agent capable of forming pores by firing, and further, a dispersing agent and / or a binder can be aggregated by firing. It can be contained to such an extent that the resulting pores and / or the pores due to the gaps between the ceramic secondary particles aggregated by firing can be formed.

  According to the present invention, there is provided a structure for a single cell of a solid oxide fuel cell obtained by the method for producing a structure for a single cell of a solid oxide fuel cell as described above.

  According to the present invention, a solid oxide fuel comprising a fuel electrode material and an air electrode material on each of the two porous ceramic material layers of the single cell structure of the solid oxide fuel cell according to any one of the above. A single cell for a battery is provided.

  According to the present invention, a solid oxide fuel cell comprising the above-described single cell for a solid oxide fuel cell is provided. Furthermore, according to the present invention, there is provided a method for producing a solid oxide fuel cell, wherein the two porous ceramic material layers of the structure for a single cell of a solid oxide fuel cell according to any one of the above are used. There is provided a manufacturing method including a step of holding a fuel electrode material and an air electrode material, respectively.

  ADVANTAGE OF THE INVENTION According to this invention, the ceramic structure for the housing | casing of a ceramic device provided with the laminated structure where two porous ceramic material layers oppose on both sides of a dense ceramic material layer is provided.

  The present invention relates to a structure for a SOFC single cell, a manufacturing method thereof, a SOFC single cell, a SOFC including the single cell, and a manufacturing method thereof.

  The SOFC single cell structure of the present invention has a laminated structure comprising at least three layers having a porous ceramic material layer sandwiching a dense ceramic material layer containing an oxide ion conductive material. This single-cell structure includes a porous ceramic material layer so as to face a dense ceramic material layer containing an oxide ion conductive ceramic material that functions as a solid electrolyte. Each of these porous ceramic material layers can carry an electrode material. That is, this single-cell structure includes a dense ceramic material layer as a solid electrolyte of SOFC and a porous ceramic material layer as a positive electrode and negative electrode carrier (skeleton). The present invention intends to prepare an SOFC by preparing such a structure for a single cell in advance and supporting an electrode material on each of these porous ceramic material layers.

  In the production of SOFC, there has never been such a strategy for producing a single cell. Conventionally, a single cell is merely manufactured by sequentially laminating other elements on a solid electrolyte or an electrode. A structure including a porous ceramic material layer serving as a carrier layer of an electrode material with respect to a dense ceramic material layer serving as a solid electrolyte layer in advance, as in the single cell structure of the present invention, By supplying and supporting an electrode material on these porous ceramic material layers, an SOFC single cell having strength and appropriate thickness can be produced without various restrictions. For this reason, the freedom degree of single cell design is improved, the battery characteristic of SOFC can be improved easily, and SOFC which can reduce internal resistance and can realize high output can be provided.

  In the single cell structure of the present invention, the dense ceramic material layer functioning as a solid electrolyte is held by two porous ceramic material layers, and each porous ceramic material layer has two remaining layers (dense And the other porous ceramic material layer). For this reason, the strength of the structure itself can be easily secured. Therefore, it is not necessary to increase the thickness of some elements in order to ensure the strength as in the prior art, and it is possible to avoid restricting the thickness, material, etc. of other elements in order to ensure such strength.

  In addition, according to the single cell structure of the present invention, the strength of the structure itself can be easily secured, and thus the strength of the SOFC can be easily secured. And can be thinned. In addition, according to the single cell structure of the present invention, since the electrode skeleton is integrated with the solid electrolyte in advance, process restrictions can be avoided or reduced.

  From the above, the use of this single cell structure for SOFC reduces the thickness, material, and process restrictions of the solid electrolyte and electrode, so that the internal resistance of the cell, gas flowability, expansion of the conductive path, Optimization of the thermal contraction rate and the like in the cell can be realized with a high degree of freedom. For this reason, it is possible to obtain a SOFC single cell and SOFC in which deterioration of the cell is suppressed, the output is high, and various electrode performances are improved.

  ADVANTAGE OF THE INVENTION According to this invention, the ceramic structure for the housing | casing of a ceramic device provided with the laminated structure where two porous ceramic material layers oppose on both sides of a dense ceramic material layer is provided.

  According to the ceramic structure for a ceramic device housing of the present invention, since it includes a dense ceramic material layer and a porous ceramic material layer, as a ceramic device that requires one of a functionally dense layer or a porous layer. Can be easily secured. Moreover, according to this ceramic structure, since the dense ceramic material layer and the porous ceramic material layer are integrated in advance, a ceramic device can be easily manufactured by using this ceramic structure.

  Hereinafter, various embodiments of the present invention will be described.

(SOFC single cell structure)
The cell structure of the present invention can have a laminated structure in which two porous ceramic material layers are opposed to each other with a dense ceramic material layer containing an oxide ion conductive ceramic material interposed therebetween. As the oxide ion conductive ceramic material contained in the dense ceramic material layer, a conventionally known ceramic material can be used without particular limitation as a solid electrolyte of SOFC. Examples thereof include oxide ion conductive ceramic materials such as ceria-based oxides doped with samarium, gadolinium, etc., lanthanum galide-based oxides doped with strontium or magnesium, and zirconia-based oxides containing scandium or yttrium.

  The dense ceramic material layer may contain one type of oxide ion conductive ceramic material, or may contain two or more types. It is also possible to provide two or more types of dense ceramic material layers containing different oxide ion conductive ceramics. The ceramic material and the laminated structure constituting the dense ceramic material layer can be appropriately selected according to the characteristics required for SOFC.

  It is preferable that the dense ceramic material layer has a preferable thickness and planar shape when the SOFC single cell is used. The thickness of the dense ceramic material layer is not particularly limited, but can be 5 μm or more and 300 μm or less. This is because, within this range, good mechanical strength and power generation characteristics can be obtained. Preferably they are 5 micrometers or more and 100 micrometers or less, More preferably, they are 5 micrometers or more and 20 micrometers or less. The dense ceramic material layer can have various planar shapes such as a square shape, a rectangular shape, and a circular shape.

  The dense ceramic material layer only needs to have the denseness required for a SOFC solid electrolyte. Those skilled in the art can easily set the density of the dense ceramic material layer according to the material and the like.

  Although the ceramic material which comprises a porous ceramic material layer is not specifically limited, It is preferable to contain the same ceramic material as the ceramic material contained in a dense ceramic material layer. In this way, good integrity and strength of the laminated structure can be ensured. Therefore, the porous ceramic material layer preferably contains the oxide ion conductive ceramic material contained in the dense ceramic material layer. Similar to the dense ceramic material layer, one or more oxide ion conductive ceramic materials can be included.

  The porous ceramic material layer has a large number of pores. The pores are preferably at least partially continuous pores, more preferably substantially substantially continuous pores. If the pores are not continuous, the loading of the electrode material is limited as will be described later, and the electrode function is impaired unless gas flowability is ensured. The porosity of the porous ceramic material layer is not particularly limited, but can be, for example, about 20% to 85%. The porosity can be easily controlled by those skilled in the art by adjusting the type and amount of the pore-forming agent.

  The porous ceramic material layer may be a single layer or may be composed of two or more porous ceramic material layers. The porosity and pore diameter can be made different in the ceramic material within a single layer, or can be made different over two or more layers.

  It is preferable that the porous ceramic material layer has a preferable thickness and planar shape when the SOFC single cell is used. The thickness of the porous ceramic material layer is not particularly limited, but can be 5 μm or more and 1000 μm or less. This is because, within this range, good mechanical strength and power generation characteristics can be obtained. Preferably they are 5 micrometers or more and 300 micrometers or less, More preferably, they are 5 micrometers or more and 100 micrometers or less. The porous ceramic material layer can be provided with various planar shapes such as a square shape, a rectangular shape, and a circular shape. The porous ceramic material layer preferably has the same planar form as the dense ceramic material layer.

  The two porous ceramic material layers facing each other with the dense ceramic material layer interposed therebetween may be composed of the same ceramic material or different from each other. May be the same or different from each other. Further, two or more porous ceramic material layers may be provided on one side of the dense ceramic material layer, and a single porous ceramic material layer may be provided on the other side.

  According to the SOFC single cell structure of the present invention, by providing such a laminated structure, the solid electrolyte can be made thinner and the thickness of the electrode can be made thinner than the conventional electrode-supported cell. For this reason, the difference in the thermal shrinkage rate in the cell can be reduced more easily than in the prior art, and warping and peeling are suppressed. Furthermore, since the porosity and the degree of freedom of the pore diameter in the porous ceramic material layer are improved, it is possible to easily form an optimum interface structure for securing a three-phase interface. Moreover, at least one, preferably both porous ceramic material layers and dense ceramic material layers contain the same ceramic material, preferably an oxide ion conductive ceramic material, thereby expanding the oxide ion conduction path. Thus, the electrode characteristics can be easily improved. Further, for the same reason, the difference in the heat shrinkage rate is suppressed, the warpage of the single cell structure is more effectively suppressed, and an SOFC excellent in flatness can be easily obtained.

(Manufacturing method of single cell structure)
The manufacturing method of the structure for SOFC single cells of the present invention comprises a step of preparing a laminate of ceramic raw material layers that are precursors of the structure for single cells of the present invention, and a step of firing the precursor. be able to.

(Precursor preparation process)
The precursor is a laminate in which a porous ceramic raw material layer capable of forming two porous ceramics is opposed across a dense ceramic raw material layer capable of forming a dense ceramic material layer containing oxide ion conductive ceramics. It has a structure. Such a laminated structure can be obtained by sequentially laminating ceramic green sheets produced by a known method, or sequentially coating ceramic slurry in layers. Considering that high technology is required to form a thin dense raw material layer on a porous raw material layer with poor surface smoothness, it is preferable to prepare ceramic green sheets corresponding to each raw material layer in advance. These are laminated to prepare a precursor.

  Hereinafter, an example will be described with respect to a process in which ceramic green sheets respectively corresponding to the dense ceramic material layer and the porous ceramic material layer are prepared in advance and laminated in a desired order to obtain a precursor.

  The ceramic green sheet to be the dense ceramic raw material layer can be obtained by coating a ceramic slurry containing the ceramic material used for the dense ceramic material layer described above and forming it into a sheet shape. The slurry can be obtained, for example, by adding an appropriate amount of a binder resin, an organic solvent, and the like, with an oxide ion conductive ceramic material as a main component, and mixing them uniformly. A sheet-like molded body can be obtained by molding the slurry thus prepared by a sheet molding method using a coating apparatus such as a knife coater or a doctor blade. The obtained sheet is dried according to a conventional method and then heat-treated as necessary to obtain a ceramic green sheet that becomes a dense ceramic material layer.

  As already explained, since the dense ceramic material layer can be composed of two or more dense ceramic material layers that differ in ceramic materials, etc., it is for two or more types of dense ceramic material layers that differ in composition etc. Ceramic green sheets may be prepared. Further, the shape and thickness of the ceramic green sheet are appropriately determined in consideration of the intended dense ceramic material layer.

  Moreover, the ceramic green sheet used as the porous ceramic raw material layer is the same as the ceramic green sheet for the dense ceramic raw material layer, for example, from a slurry mainly composed of the same oxide ion conductive material as the dense ceramic raw material layer. Can be obtained. The slurry for the porous ceramic raw material layer is different from the slurry for the porous ceramic raw material layer in that it has a composition capable of forming pores.

  The slurry for the porous ceramic material layer can contain, for example, a pore-forming agent capable of forming pores by a subsequent firing step. As the pore-forming agent, any material may be used as long as it is made of an organic material that is burned off at the firing temperature of the single-cell structure from among known pore-forming agents. As a material for the pore-forming agent, for example, a resin material such as polymethacrylic acid resin or polystyrene resin, carbon, or the like can be used. The shape of the pore-forming agent is not particularly limited, but isotropic particles are preferably used, more preferably spherical particles, in view of pore dispersibility and resultant gas diffusion effect.

  The porosity and pore diameter in the porous ceramic material layer can be easily adjusted by adjusting the amount of the pore former and the particle diameter. For example, in order to form pores corresponding to the particle diameter of the pore forming agent in the porous ceramic material layer, the pore forming agent should be contained in a well-dispersed state while avoiding aggregation of the pore forming agent. . That is, the amount of pore-forming agent and the addition of a dispersant are considered. In addition, in order to form pores according to the secondary particle diameter of the pore-forming agent and pores based on the gap between the secondary particles of the ceramic particles, the content of the dispersant and / or the binder in the slurry It can be realized by adjusting. For example, the dispersibility of the pore-forming agent and ceramic particles is lowered by reducing or making the amount of the dispersant lower than or optimal with respect to the optimum amount (the amount by which the slurry is well dispersed), thereby forming the pores as described above be able to. Further, by increasing the amount of the binder, it is possible to easily form the secondary particles for the pore-forming agent and the ceramic particles, thereby forming the pores as described above. In addition, the control of the dispersibility of the pores can be performed according to Japanese Patent Application Laid-Open No. 2008-004422.

  The porosity and pore diameter control using the dispersant as described above are useful in the casting molding method and the tape molding method, which are ceramic molding methods using ceramic slurry.

  As already described, the pore diameter and the porosity may be different from each other between the porous ceramic material layers facing each other with the dense ceramic material layer interposed therebetween, or may be substantially the same. Further, two or more types of ceramic green sheets may be produced so as to form two or more porous ceramic material layers having different pore diameters and porosity on the same side (same pole side). Further, the shape and thickness of the ceramic green sheet are appropriately determined in consideration of the intended dense ceramic material layer.

  A precursor can be obtained by laminating ceramic green sheets thus prepared. The precursor may be moderately pressurized prior to firing.

(Precursor firing step)
The firing step of the precursor is a step of firing the precursor to form a laminated structure of the single cell structure of the present invention. The firing temperature, firing time, temperature raising condition, firing atmosphere, and the like are appropriately determined in consideration of the laminated structure of the precursor, the size of the precursor, and the like in addition to the composition of each ceramic green sheet.

  The single cell structure obtained through the precursor preparation step and the firing step has a laminated structure in which two porous ceramic material layers are opposed to each other with a dense ceramic material layer interposed therebetween, and these are fired integrally. ing. For this reason, the cell structure has good integrity. In addition, the integrated firing allows the interface between the porous ceramic material layer and the dense ceramic material layer to adhere well, and when the porous ceramic material layer contains an oxide ion conductive ceramic material, the oxide ion conduction path is expanded. It has been made. Moreover, since it has such a laminated structure, its own strength is ensured and the handling property is also good.

  The SOFC single cell structure obtained by the method for producing a SOFC single cell structure of the present invention has the characteristics as described above, and is distinguished from one that is not integrally fired.

(SOFC single cell and SOFC)
The SOFC single cell of the present invention can be provided with a fuel electrode material and an air electrode material respectively on two porous ceramic material layers opposed to each other with the dense ceramic material layer of the single cell structure of the present invention interposed therebetween. According to such a SOFC single cell, the effect exhibited by the single cell structure of the present invention can be obtained in the SOFC single cell. In other words, the cell has a sufficient strength even when it is thin, can exhibit excellent electrode characteristics, can be expected to have a high output, and has a suppressed warpage. In the porous ceramic material layer, air permeability is ensured even if there is an electrode material on the inner wall surface.

  The electrode material provided in the porous ceramic material layer is not particularly limited, and those used as a fuel electrode material in a known SOFC can be used. Examples thereof include a mixture of a metal catalyst and a ceramic powder material made of an oxide ion conductor or a composite powder thereof. In addition to the powder material, a precursor solution that becomes a fuel electrode material by firing can also be used. As the metal catalyst used at this time, a material that is stable in a reducing atmosphere such as nickel, iron, cobalt, noble metals (platinum, ruthenium, palladium, etc.) and has hydrogen oxidation activity can be used. As the precursor, a nickel nitrate solution, a nickel acetate solution, or the like can be used. Further, as the oxide ion conductor, those having a fluorite structure or a perovskite structure can be preferably used. Examples of those having a fluorite structure include ceria-based oxides doped with samarium, gadolinium, and the like, and zirconia-based oxides containing scandium and yttrium. In addition, examples of those having a perovskite structure include lanthanum galide oxides doped with strontium and magnesium. Among the materials described above, the fuel electrode is preferably formed of a mixture of an oxide ion conductor and nickel. The fuel electrode material can be used alone or in combination of two or more. Further, the fuel electrode material can be constituted by using a metal catalyst alone.

Moreover, as an air electrode material, what is used as an air electrode material in well-known SOFC can be used, without specifically limiting. For example, a metal oxide made of Co, Fe, Ni, Cr, Mn, or the like having a perovskite structure can be used. Specifically, (Sm, Sr) CoO ₃ , (La, Sr) MnO ₃ , (La, Sr) CoO ₃ , (La, Sr) (Fe, Co) O ₃ , (La, Sr) (Fe, Co , Ni) O _{3 and the} like, and (La, Sr) MnO ₃ is preferable. An air electrode material can be used individually by 1 type or in mixture of 2 or more types.

  These electrode materials are preferably provided in the form of a film or a layer on the pore inner wall of the porous ceramic material layer. Moreover, it does not necessarily have to be uniform throughout the porous ceramic material layer, and may be provided dispersedly. A method for holding the electrode material will be described later.

  The SOFC is configured by combining elements (for example, a current collector and a separator) necessary as the SOFC with the SOFC single cell configured as described above. Necessary elements and battery configurations are well known to those skilled in the art, and those skilled in the art can easily produce a SOFC using the SOFC single cell of the present invention.

(SOFC single cell and SOFC manufacturing method)
In the SOFC single cell and the SOFC manufacturing method of the present invention, the fuel electrode material and the air electrode material are respectively applied to two porous ceramic material layers opposed to each other with the dense ceramic material layer of the single cell structure of the present invention interposed therebetween. A step of supplying and holding can be provided. According to the manufacturing method of the present invention, since the solid electrolyte is provided in advance and the skeleton of the fuel electrode and the air electrode is provided, the process constraints for ensuring strength and dissimilar materials are avoided or reduced. This process can be simplified. Moreover, since the porous property required for the electrode is secured to some extent in the porous ceramic material layer already provided in the single cell structure, it is possible to omit adding a pore forming agent or the like to the electrode material. When the porous ceramic material layer contains an oxide ion conductive ceramic material, a good oxide ion conductive path is established.

  In order to supply and hold the electrode material to the single cell structure of the present invention, a known ceramic material film forming method or the like can be employed without any particular limitation. For example, electrode materials are added as pastes or slurries by adding organic substances such as glycerin, dibutyl phthalate, dioctyl phthalate, polyethylene glycol, etc., by screen printing, knife coating, spin coating, spray coating, dip coating (impregnation), etc. , And can be supplied to each porous ceramic material layer. Then, the electrode material is applied to the porous ceramic material layer, specifically, the pore inner wall by drying and firing. The fuel electrode material is reduced under the operating conditions of the SOFC and functions as a fuel electrode.

(Ceramic structure for ceramic device housing)
The ceramic structure for a casing of a ceramic device of the present invention can have a laminated structure in which two porous ceramic material layers are opposed to each other with a dense ceramic material layer interposed therebetween.
The ceramic structure of the present invention can be used for various ceramic devices, for example, a gas sensor such as oxygen or a separation filter. Any of these can make the dense ceramic layer and / or the porous ceramic layer an essential constituent in terms of function. The ceramic structure of the present invention constitutes at least a part of the functional essential components of such a ceramic device, and can also provide a portion that becomes a casing of the ceramic device.

  In the ceramic structure of the present invention, the ceramic material used for the dense ceramic material layer and the porous ceramic material layer, the thickness thereof, and the like can be determined according to the application of the ceramic device.

  For example, when the ceramic structure of the present invention is used for a part of a gas sensor such as an oxygen sensor and its casing, the dense ceramic material layer functions as a gas separation membrane and an ion conductive material, and the porous ceramic material layer Functions as a reaction field and support. In this case, an oxide ion conductive material such as zirconia-based ceramics or ceria-based ceramics is used as the dense ceramic material layer, and the porous ceramic material layer is not particularly limited, but the dense ceramic material layer is dense from the viewpoint of strength and integrity. The same ceramic material as the ceramic material layer can be used.

  Further, when the ceramic structure of the present invention is used for a part of the separation filter and its casing, the dense ceramic material layer functions as a separation membrane and the porous ceramic material layer functions as a support. In this case, oxide ceramics such as alumina, zirconia, cordierite, and silica can be used as the dense ceramic material layer, and the porous ceramic material layer is not particularly limited, but is related to strength, integrity, and the like. The same ceramic material as the dense ceramic material layer can be used.

  The ceramic structure of the present invention can be directly applied to the various embodiments of the SOFC single cell structure and the manufacturing method thereof, except that a ceramic material corresponding to the type of ceramic device is used.

  In the ceramic structure of the present invention, the dense and porous in the dense ceramic material layer and the porous ceramic material layer are relatively determined in the ceramic structure. That is, in the ceramic structure of the present invention, the porosity and the like of the dense ceramic material layer are not particularly limited as long as the density is suitable for the application of the ceramic device, and is more porous than the dense ceramic material. May be a porous ceramic material layer. Therefore, the dense ceramic material layer may also be porous having pores.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, A various change is possible unless it deviates from the meaning of this invention.

  EXAMPLES Hereinafter, although an Example is given and an example is demonstrated concretely, this invention is not limited to a following example.

Gd _0.2 Ce _0.8 O _x (GDC) was used as the ceramic material, and polymethyl methacrylate beads (PMMA, average diameter: 20 μm) were used as the pore former. Using a GDC slurry (Table 1) for dense parts composed of ethanol, maleic acid polyether copolymer (dispersing agent), polyvinyl butyral (binder), and benzylbutyl phthalate (plasticizer), 15-30 mm A thin green sheet was formed (sheet for dense part). Separately, a well-dispersed GDC / PMMA slurry was prepared (Table 1, unit: g), and a green sheet for a porous part of 150 to 300 mm was formed in the same manner. The green sheet laminate laminated in the order of the porous sheet / dense sheet / porous sheet was fired at 1450 ° C. for 8 hours to obtain a ceramic laminate 1 having PMMA-derived pores in the porous portion. A photograph of the cross section is shown in FIG.

  As shown in FIG. 1, according to this example, an SOFC single cell structure having good integrity could be obtained. That is, the dense ceramic material layer had a thickness of 30 μm and was sufficiently dense, and the porous ceramic material layer had a thickness of 140 μm and the intended porosity.

  Agglomerated GDC / PMMA slurry having the composition shown in Table 1 was prepared, and a green sheet for a porous part of 150 to 300 mm was formed in the same manner. The green sheet laminate, in which the porous part sheet / dense sheet / porous part sheet were stacked in this order, was fired at 1450 ° C. for 8 hours, and in addition to the PMMA-derived pores, the GDC aggregate particle gaps and the aggregated PMMA-derived pores A ceramic laminate 2 in which was introduced was obtained. A photograph of the cross section is shown in FIG.

  As shown in FIG. 2, the porous ceramic material layer had a very high porosity with a thickness of 180 μm. Moreover, despite the unevenness at the interface with the porous ceramic material layer, the dense ceramic material layer was held in the single cell structure with good integrity.

  Using a yttria-stabilized zirconia (YSZ) slurry having the composition shown in Table 1, a YSZ thin film green sheet for a dense part was formed by a doctor blade. Laminate ceramics composed of two types of oxide ion conductive materials by laminating in order of porous part sheet / dense GDC sheet / dense YSZ sheet / porous part sheet and firing at 1450 ° C. for 8 hours. Body 3 was obtained. A photograph of the cross section is shown in FIG.

  As shown in FIG. 3, the dense ceramic material layer was formed with good integrity even though the dense ceramic material layer was laminated using different types of ceramic materials. In addition, any dense ceramic material layer was bonded to the porous ceramic material layer with good integrity.

A platinum electrode was introduced into the porous part of a ceramic laminate (diameter 16 mm, dense part thickness: 30 μm, porous part thickness: 150 μm) composed of GDC to produce a single cell for SOFC. A photograph of the cross section is shown in FIG. When a power generation test was conducted at 700 ° C. using 3% humidified hydrogen (50 ml / min) as the fuel and air (50 ml / min) as the oxidant, an output of 100 mW / cm ² was obtained. The results are shown in FIG.

  As shown in FIG. 4, platinum was dispersed and fixed throughout both porous portions of the single cell structure. Moreover, as shown in FIG. 5, a favorable output could be obtained.

It is a figure which shows an example (photograph) of a ceramic laminated body. It is a figure which shows another example (photograph) of a ceramic laminated body. It is a figure which shows another example (photograph) of a ceramic laminated body. It is a figure which shows the photograph of the GDC laminated body with which the platinum electrode was carry | supported. It is a figure which shows the electric power generation result (graph) of the GDC laminated body with which the platinum electrode was carry | supported.

Claims (12)

  A structure for a single cell of a solid oxide fuel cell, comprising a laminated structure in which two porous ceramic material layers are opposed to each other with a dense ceramic material layer containing an oxide ion conductive ceramic material interposed therebetween.   The single-cell structure according to claim 1, wherein the dense ceramic material layer contains two or more kinds of ceramic materials.   The single-cell structure according to claim 2, wherein the dense ceramic material layer has two or more types of ceramic material layers.   The single-cell structure according to any one of claims 1 to 3, wherein the porous ceramic material layer contains the same ceramic material as that contained in the dense ceramic material layer. A method for producing a structure for a single cell of a solid oxide fuel cell, comprising:
Preparing a precursor of a ceramic laminate having a laminated structure in which a porous ceramic raw material layer capable of forming two porous ceramics is sandwiched across a dense ceramic raw material layer capable of forming a dense ceramic; Firing the precursor;
A method for producing a structure for a single cell of a solid oxide fuel cell.   The said porous ceramic raw material layer is a manufacturing method of Claim 5 containing the pore making agent which can form a pore by baking.   The porous ceramic material layer can further form pores resulting from the aggregation of the pore-forming agent and / or pores resulting from the agglomeration of the ceramic secondary particles agglomerated by firing by firing the dispersant and / or binder. The production method according to claim 6, which is contained to a certain extent.   A structure for a single cell of a solid oxide fuel cell obtained by the method for producing a structure for a cell of a solid oxide fuel cell according to any one of claims 5 to 7.   6. A solid oxide fuel cell comprising a fuel electrode material and an air electrode material in each of the two porous ceramic material layers of the structure for a single cell of the solid oxide fuel cell according to claim 1. Single cell for use.   A solid oxide fuel cell comprising the single cell for a fuel cell according to claim 9. A method for producing a solid oxide fuel cell, comprising:
A step of holding the fuel electrode material and the air electrode material respectively in the two porous ceramic material layers of the structure for a single cell of the solid oxide fuel cell according to claim 1, Production method. A ceramic structure for a ceramic device housing, comprising a laminated structure in which two porous ceramic material layers are opposed to each other with a dense ceramic material layer interposed therebetween.