Preparation method of flat plate type SOFC half cell and flat plate type SOFC total cell

Abstract

The invention discloses a preparation method of a flat plate type solid oxide fuel cell (SOFC) half cell and a flat plate type SOFC full cell, and relates to the technical field of solid oxide fuel cells, the preparation method of the flat plate type SOFC half cell and the flat plate type SOFC full cell provided by the invention can solve the problems of electrolyte layer scratch, indentation and the like caused by a setter plate in the glue discharging and sintering stages, and also can double the sintering yield; and the production efficiency is improved, and the method is suitable for large-scale production of flat and intact SOFC half cells and SOFC full cells.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide fuel cells, and in particular to a method for preparing a planar SOFC half cell and a full cell. Background Art

[0002] Solid oxide fuel cell (SOFC) belongs to the third generation of solid fuel cells. It is a power generation device that directly converts chemical energy stored in fuel into electrical energy at medium and high temperatures, and has broad application prospects. Currently, SOFC is mainly divided into tubular and flat-plate types, among which the flat-plate type is divided into electrolyte-supported type and anode-supported type; the anode-supported type has been deeply studied by the industry due to its thin electrolyte layer, short current transmission path, and high power density.

[0003] In a flat-plate anode-supported SOFC, the electrolyte layer is about 10 to 20 μm thick, the anode functional layer is about 10 to 20 μm, and the anode layer is about 400 to 1000 μm thick. During conventional sintering, the three layers undergo debinding and co-sintering, and the shrinkage characteristics of each layer are different at different temperatures, causing the half-cell to deform and warp, making it impossible to perform efficient stack packaging. To avoid debinding and co-sintering deformation, a pressure sintering method is usually used, that is, a weight plate is placed on the battery during debinding and co-sintering. This process has high requirements on the material, finish, porosity, etc. of the pressure plate, and it is also easy to cause problems such as indentations and pits on the electrolyte surface.

[0004] CN 114335640A discloses an anode-supported SOFC half-cell sintering method, comprising the following steps: S1, sequentially adding an anode functional layer and an electrolyte layer on an anode support layer to obtain a half-cell blank;

[0005] S2. Place the half-cell blank with the electrolyte layer facing upward and the anode support layer facing downward on a nickel-based porous ceramic separator, and pre-sinter to obtain a half-cell pre-sintered blank. S3. Place the electrolyte layers of two half-cell pre-sintered blanks in contact with each other, place a nickel-based porous ceramic separator on each of the anode support layers on both sides, align them to form a "symmetrical" smoothing unit, and place the aligned stack on a conventional high-temperature resistant support plate, and press another conventional high-temperature resistant support plate on the top. After high-temperature pressing and smoothing, sintering is performed to obtain a half-cell with good flatness and no indentations or depressions on the electrolyte layer. The method places a nickel-based porous ceramic separator on the anode support layer of the half-cell during the pre-firing and high-temperature pressure and smoothing sintering process of the half-cell, which can hinder the outward migration of NiO in the anode support layer of the half-cell and avoid the anode support layer becoming lighter and uneven in color; the porous structure of the nickel-based porous ceramic separator is conducive to the removal of organic matter in the half-cell blank debinding stage, avoiding debinding cracking, bulging, etc.; through two-step sintering: pre-firing and "symmetrical" high-temperature pressure and smoothing sintering, the smooth electrolyte layers are brought into contact with each other during the smoothing process, so that an anode-supported SOFC half-cell with good flatness and no pits or scratches on the electrolyte layer can be prepared. Although this method can utilize the porous structure of the nickel-based porous ceramic separator for debinding, the debinding mold is still directly pressed on the electrolyte layer, causing scratches, crushing and other defects on the electrolyte layer due to shrinkage during debinding; in addition, this method performs two sintering steps, which has high energy consumption and low sintering output. In addition, during the second sintering, the electrolyte layers of the two half-cell pre-sintered blanks are in contact with each other, which is prone to sintering adhesion at high temperatures, damaging the electrolyte layer. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing a flat-plate SOFC half-cell and a full-cell, which can not only solve the problems of scratches and indentations on the electrolyte layer caused by the support plate during the debinding and sintering stages, but also double the sintering output and improve production efficiency, and is suitable for large-scale production of flat and intact SOFC half-cells and SOFC full-cells.

[0007] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0008] One of the objects of the present invention is to provide a method for preparing a planar SOFC half-cell, comprising the following steps:

[0009] (1) preparing a planar SOFC half-cell green body comprising an anode support layer, an anode functional layer, and an electrolyte layer, and then placing the planar SOFC half-cell green body in a mold for debinding to obtain a half-cell debinding green body;

[0010] (2) stacking the electrolyte layers of two half-cell stripping blanks relative to each other and adding isolation powder between the two electrolyte layers to form a symmetrical sintered unit;

[0011] (3) placing the symmetrical sintering unit between two support plates for weight sintering;

[0012] (4) The sintered symmetrical sintered unit is taken out, and the isolation powder on the surface of the electrolyte layer is removed to obtain a planar SOFC half-cell.

[0013] The second object of the present invention is to provide a method for preparing a planar SOFC full cell, comprising the following steps:

[0014] (1) preparing a planar SOFC half cell according to the aforementioned method;

[0015] (2) preparing barrier layers on the electrolyte side of the planar SOFC half-cell in sequence and then sintering them;

[0016] (3) A cathode layer is prepared on the barrier layer, and then sintered to obtain a planar SOFC full cell.

[0017] The beneficial effects of the present invention are:

[0018] 1. In view of the problem that the green body is prone to warping and deformation during conventional debinding, the present invention uses a porous ceramic carrier with a gap structure design during the debinding stage. On the one hand, the gap structure design prevents the upper plate from directly pressing on the SOFC half-cell green body, thereby avoiding scratches, crushing and other defects in the electrolyte layer caused by shrinkage during the debinding stage; on the other hand, it can limit the deformation and warping of the green body during the debinding stage, thereby obtaining a flat SOFC half-cell debinding green body, which is convenient for subsequent pressing and sintering; at the same time, the porous structure of the ceramic carrier is conducive to the decomposition and discharge of organic additives in the SOFC half-cell green body during the debinding stage, thereby avoiding the problem of cracking during debinding.

[0019] 2. In view of the problem that the support plate in the conventional single-piece pressing process easily causes scratches and crushing of the electrolyte layer, the support plate of the present invention does not contact the electrolyte layer during the sintering stage, which can effectively avoid scratches and crushing of the electrolyte layer during the sintering shrinkage process. At the same time, the isolation powder layer prevents the electrolyte layers of the two half-cells from sintering and adhesion at high temperatures, and will not damage the electrolyte layers. The stacked sintering units of two pieces in a group can double the sintering output, improve production efficiency, and are conducive to the large-scale production of flat-plate anode-supported SOFC full cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the preparation process of a planar anode-supported SOFC full cell;

[0021] Figure 2 It is a schematic diagram of the structure of a SOFC half-cell green body;

[0022] Figure 3 It is a schematic diagram of the structure of the porous ceramic upper plate;

[0023] Figure 4 Schematic diagram of the debinding and placement of the SOFC half-cell green body;

[0024] Figure 5 This is a schematic diagram of the weight sintering placement of the battery sintering unit;

[0025] Among them, 1-electrolyte layer; 10-isolation powder layer; 11-ballast plate; 12-supporting plate; 100-sintering unit; 101-half-cell green body; 2-anode functional layer; 21-porous carrier bottom plate; 22-porous carrier upper plate; 220-corner pillars; 3-anode supporting layer. DETAILED DESCRIPTION

[0026] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments and diagrams.

[0027] The present invention provides a method for preparing a planar SOFC half-cell, comprising the following steps:

[0028] (1) preparing a planar SOFC half-cell green body comprising an anode support layer, an anode functional layer, and an electrolyte layer, and then placing the planar SOFC half-cell green body in a mold for debinding to obtain a half-cell debinding green body;

[0029] (2) stacking the electrolyte layers of two half-cell stripping blanks relative to each other and adding isolation powder between the two electrolyte layers to form a symmetrical sintered unit;

[0030] (3) placing the symmetrical sintering unit between two support plates for weight sintering;

[0031] (4) The sintered symmetrical sintered unit is taken out, and the isolation powder on the surface of the electrolyte layer is removed to obtain a planar SOFC half-cell.

[0032] Figure 2 It is a schematic diagram of the structure of a SOFC half-cell green body; Figure 2 As shown, the SOFC half-cell green body includes an electrolyte layer 1, an anode functional layer 2 and an anode support layer 3. In the present invention, the preparation order of the layers of the flat anode support type SOFC half-cell green body is anode support layer 3, anode functional layer 2, and electrolyte layer 1. Among them, the anode support layer can be prepared by casting, pressing, extrusion, etc.; the anode functional layer can be prepared by casting, spraying, screen printing, deposition, etc.; the electrolyte layer can be prepared by casting, spraying, screen printing, deposition, etc. The thickness of the anode support layer is 300-1500μm; the thickness of the anode functional layer is 1-50μm; the thickness of the electrolyte layer is 1-50μm.

[0033] In the present invention, the compositions of the anode support layer, the anode functional layer and the electrolyte layer may be known to those skilled in the art. The anode support layer is composed of at least one of a NiO-3YSZ composite material and a NiO-GDC composite material.

[0034] According to the present invention, under preferred conditions, the material of the electrolyte layer may be at least one of zirconium oxide, cerium oxide, rare earth-doped zirconium oxide, and rare earth-doped cerium oxide. Wherein, the rare earth may be at least one of La, Y, Nd, Sm, Pr, Eu, Yb, and Gd. Further preferably, in order to reduce the difference between the electrolyte layer and the air electrode and improve the compatibility of the two, the material of the electrolyte layer is rare earth-doped cerium oxide, such as samarium oxide-doped cerium oxide (SDC) or gadolinium oxide-doped cerium oxide (GDC).

[0035] According to the present invention, the material of the anode functional layer includes an electronic conductive phase and an ion conductive phase; preferably, the electronic conductive phase is selected from at least one of NiO, Co3O4, CuO, Ag2O and ZnO. Preferably, the ion conductive phase is selected from metal oxides of fluorite structure and / or metal oxides of perovskite structure, and the metal oxide of fluorite structure includes but is not limited to at least one of zirconium oxide, cerium oxide, rare earth doped zirconium oxide, and rare earth doped cerium oxide, and the rare earth can be at least one of La, Y, Nd, Sm, Pr, Eu, Yb and Gd; including but not limited to one of yttria doped zirconium oxide (YSZ), samarium oxide doped cerium oxide (SDC) or gadolinium oxide doped cerium oxide (GDC). Specifically, the anode functional layer can be at least one of NiO / YSZ, NiO / GDC, NiO / SDC, CuO / YSZ, CuO / GDC, and CuO / SDC.

[0036] In the present invention, the carrier is a porous ceramic carrier. Figure 3 It is a schematic diagram of the structure of the porous ceramic upper plate. Figure 4 Schematic diagram of the debinding and placement of the SOFC half-cell green body; Figure 3 and Figure 4 As shown, the porous ceramic carrier is composed of a porous carrier upper plate 22, a porous carrier bottom plate 21, and corner pillars 220 arranged between the porous carrier upper plate 22 and the porous carrier bottom plate 21. The porous carrier upper plate 22 and the porous carrier bottom plate 21 are both planar ceramic plates. The ceramic plate is composed of at least one of zirconium oxide, aluminum oxide, and silicon carbide. The porosity of the porous ceramic carrier is 20-30%, and further preferably, the gap h between the porous carrier upper plate 22 and the half-cell green body is 0.3-0.5 mm.

[0037] In the present invention, the debinding temperature is 500-1200° C., the heating rate is 0.1-5° C. / min, and the heat preservation time is 1-5 h.

[0038] In the present invention, the isolation powder layer can be prepared by screen printing, spraying, etc. The thickness of the isolation powder added is 40-60 μm.

[0039] Furthermore, the isolation powder is at least one of aluminum oxide powder and zirconium oxide powder, and the composition of the isolation powder is different from the composition of the electrolyte; illustratively, when the electrolyte contains zirconium oxide or doped zirconium oxide, the isolation powder may not contain zirconium oxide.

[0040] Preferably, the isolation powder is spherical in shape; more preferably, the particle size of the isolation powder is 20 to 40 μm.

[0041] Figure 5 This is a schematic diagram of the pressure sintering placement of the battery sintering unit. Figure 5 As shown, the battery sintering unit is stacked in a manner that the electrolyte layers of two SOFC half-cell green sheets are in contact with each other inwardly and the anode support layers are outwardly.

[0042] In the present invention, the material of the support plate is at least one of zirconia, alumina and mullite. The pressure sintering temperature is 1000-1500°C, the heating rate is 0.1-5°C / min, and the holding time is 1-10h.

[0043] In the present invention, the isolation powder is removed by at least one of air gun blowing, grinding, and ultrasonic cleaning.

[0044] The preparation method provided by the present invention is applicable to the preparation of a flat anode-supported SOFC half-cell, a flat cathode-supported SOFC half-cell, and a flat electrolyte-supported SOFC half-cell.

[0045] Figure 1 Schematic diagram of the preparation process of a flat anode supported SOFC full cell; Figure 1 As shown, the present invention also provides a method for preparing a planar SOFC full cell, comprising the following steps:

[0046] (1) preparing a planar SOFC half cell according to the aforementioned method;

[0047] (2) preparing barrier layers on the electrolyte side of the planar SOFC half-cell in sequence and then sintering them;

[0048] (3) A cathode layer is prepared on the barrier layer, and then sintered to obtain a planar SOFC full cell.

[0049] In the present invention, the barrier layer can be prepared by screen printing, spraying, deposition and the like. The barrier layer is composed of at least one of gadolinium oxide doped cerium oxide (GDC for short), samarium oxide doped cerium oxide (SDC for short) and scandium oxide doped zirconium oxide (SSZ for short). The thickness of the barrier layer is 1 to 50 μm. The sintering temperature of the barrier layer is 1000 to 1400°C, the heating rate is 0.1 to 5°C / min, and the holding time is 1 to 10 hours.

[0050] In the present invention, the cathode layer can be prepared by screen printing, spraying, deposition, etc. The thickness of the cathode layer is 1 to 50 μm. The sintering temperature of the cathode layer is 1000 to 1400° C., the heating rate is 0.1 to 5° C. / min, and the insulation time is 1 to 10 hours.

[0051] The types of active materials of the cathode layer are known to those skilled in the art, including but not limited to fluorite-structured metal oxides and / or perovskite-structured metal oxides; the perovskite-structured metal oxides include but are not limited to LSCF (lanthanum strontium cobalt iron), LSM (lanthanum strontium manganese), and LSC (lanthanum strontium cobalt).

[0052] The preparation method provided by the present invention is applicable to the preparation of a flat-plate anode-supported SOFC full cell, a flat-plate cathode-supported SOFC full cell, and a flat-plate electrolyte-supported SOFC full cell.

[0053] The English abbreviations in the present invention are as follows:

[0054] NiO: nickel oxide;

[0055] 3YSZ: 3% mol yttrium stabilized zirconium oxide;

[0056] 8YSZ: 8% mol yttrium stabilized zirconium oxide;

[0057] GDC: gadolinium oxide doped ceria;

[0058] SDC: samarium oxide doped cerium oxide;

[0059] PVB: polyvinyl butyral, purchased from Tianyuan Technology Group;

[0060] DBP: dibutyl phthalate;

[0061] PEG200: polyethylene glycol, purchased from Haian Petrochemical Plant, Jiangsu Province.

[0062] Example 1

[0063] (1) A planar SOFC half-cell green body comprising an anode support layer, an anode functional layer, and an electrolyte layer is prepared.

[0064] Firstly, an anode support layer with a thickness of 700 μm was prepared by a tape casting method. The composition of the anode support layer tape casting slurry was: 30 wt% NiO and 25 wt% 3YSZ as powder raw materials, 20 wt% ethanol and 15 wt% butanone as solvents, 5 wt% PVB as a binder, 2 wt% PEG 200 and 2 wt% DPB as plasticizers, and 1 wt% triethanolamine as a dispersant.

[0065] Then, a 20 μm thick anode functional layer was prepared on the anode support layer by screen printing. The composition of the anode functional layer screen printing slurry was: 40 wt% NiO and 20 wt% 8YSZ as powder raw materials, 32 wt% pine alcohol as solvent, 1 wt% ethyl cellulose as binder, and 7 wt% fish oil as dispersant.

[0066] Finally, a 20 μm thick electrolyte layer was prepared on the anode functional layer by screen printing. The electrolyte layer was composed of 60 wt% 8YSZ as powder raw material, 33 wt% pine alcohol as solvent, 1 wt% ethyl cellulose as binder, and 6 wt% fish oil as dispersant.

[0067] (2) The SOFC half-cell green body was placed in a porous ceramic carrier with a gap structure design for debinding. The temperature was raised to 300°C at a heating rate of 0.5°C / min and kept at that temperature for 1 hour. Then, the temperature was raised to 500°C at a heating rate of 0.5°C / min and kept at that temperature for 1 hour. Then, the temperature was raised to 1100°C and kept at that temperature for 2 hours. The state of the SOFC half-cell debinding green body after debinding is shown in Tables 1 and 2.

[0068] The porous ceramic carrier includes a porous carrier bottom plate and a porous carrier upper plate. Ceramic pillars are arranged at the four corners of the porous carrier upper plate. The porosity of the porous ceramic bottom plate and the porous ceramic upper plate are both 20%, and the gap h between the upper plate and the half-cell green body is 0.3 mm.

[0069] (3) A 40 μm thick isolation powder layer is prepared by spraying on the electrolyte layer surface of the debonded SOFC half-cell blank after debonding. The isolation powder is spherical alumina with a particle size of 30 μm.

[0070] (4) The electrolytes of two SOFC half-cell debonded blanks are stacked relative to each other and the anode support layers are aligned outward to form a symmetrical sintering unit.

[0071] (5) The symmetrical sintering unit is placed between two support plates for weight sintering. The temperature is increased to 1400°C at a heating rate of 3°C / min and kept at this temperature for 4 hours. The material of the support plates is zirconia.

[0072] (6) The sintered battery sintering unit is taken out, and the isolation powder on the surface of the electrolyte layer is removed by air gun blowing to obtain a SOFC half-cell. The state of the SOFC half-cell is shown in Table 3 and Table 4.

[0073] (7) A barrier layer with a thickness of 5 μm was prepared on the electrolyte layer of the SOFC half-cell by screen printing. The barrier layer screen printing slurry used GDC as the powder raw material, and added pine alcohol as a solvent, ethyl cellulose as a binder, and fish oil as a dispersant as auxiliary materials. After screen printing and drying, the temperature was increased to 1100°C at a heating rate of 2°C / min and sintered for 2 hours.

[0074] (8) A cathode layer with a thickness of 20 μm was prepared on the barrier layer of the SOFC half-cell by screen printing. The cathode layer screen printing slurry was LSCF, and pine alcohol was added as a solvent, ethyl cellulose as a binder, and fish oil as a dispersant as auxiliary materials. After screen printing and drying, the temperature was increased to 1050°C at a heating rate of 2°C / min and sintered for 2 hours to obtain a SOFC full cell.

[0075] Examples 2 to 3 and Comparative Examples 1 to 9

[0076] The method of Example 1 was followed, except that the gap between the porous ceramic upper plate and the half-cell green body was adjusted. The state of the debinding SOFC half-cell green body after debinding is shown in Table 1.

[0077] Table 1

[0078]

[0079]

[0080] It can be seen from Table 1 that when the gap between the upper plate and the half-cell green body is 0.3-0.5 mm, the half-cell green body is flat after debinding, and there are no indentations or pits on the surface of the electrolyte layer; when there is no gap between the upper plate and the half-cell green body or the gap is less than 0.3 mm, although the half-cell green body is flat after debinding, the half-cell green body is deformed by heat during the debinding process and contacts the upper plate, which will form a small amount of indentations on the surface of the electrolyte layer; when the gap between the upper plate and the half-cell green body is greater than 0.5 mm, it cannot play a good role in limiting deformation, and the half-cell green body will deform and warp after debinding.

[0081] Example 4 and Comparative Examples 10 to 12

[0082] According to the method of Example 1, Example 4 and Comparative Examples 10 to 12 were carried out, except that porous ceramic carriers with different porosities were used. The state of the debinding blank of the SOFC half-cell after debinding is shown in Table 2.

[0083] Table 2

[0084]

[0085] It can be seen from Table 2 that the porosity of the porous ceramic plate has a significant effect on the strength of the ceramic plate itself and the debinding effect; when the porosity is greater than 30%, although it is conducive to the full debinding of the half-cell green body, and the debinding green body will not produce cracking defects after debinding, but too high a porosity will reduce its own strength, and it is easy to break during use and is not durable; when the porosity is less than 20%, although the ceramic plate has high strength and can be reused for a long time, it is not conducive to the decomposition and discharge of organic matter in the green body, causing the half-cell debinding green body to crack; when the porosity is 20-30%, the ceramic plate has good strength and a higher porosity, and the battery debinding green body will not crack after debinding.

[0086] Examples 5 to 7 and Comparative Examples 13 to 22

[0087] According to the method of Example 1, Examples 5 to 7 and Comparative Examples 13 to 22 were carried out, except that the material, morphology or particle size of the isolation powder was adjusted. The state of the obtained half-cell is shown in Table 3.

[0088] Table 3

[0089]

[0090] From Table 3 we can see that:

[0091] Comparing Example 1 and Example 5, zirconium oxide isolation powder is used. Because it and the electrolyte layer are both made of zirconium oxide, sintering and melting will occur at high temperature, and the isolation powder will adhere to the electrolyte layer, adhere to the surface and be difficult to remove, and will damage the electrolyte layer; using alumina isolation powder will not adhere to the electrolyte layer and can be easily removed after sintering.

[0092] Comparative Examples 6, 7 and Comparative Examples 13 to 17, when spherical powders are selected as isolation powders, regardless of their materials such as alumina or zirconia, if the particle size is small (less than 20 μm), the finer powders will sinter and agglomerate at high temperatures due to their greater sintering activity, forming block-like agglomerates, causing crushing or indentations, and damaging the surface of the electrolyte layer; when the particle size is large (greater than 40 μm), it will itself act as large particles, causing crushing or indentations; by comparison, when the isolation powder particle size is between 20 and 40 μm, it can not only play an isolation role, but also will not produce sintering agglomerations or cause crushing or indentations to the electrolyte layer due to its large particle size.

[0093] By comparing Examples 1, 5 to 7 and Comparative Examples 19 to 22, it can be found that the microscopic morphology of the isolation powder will also have a significant effect on the surface state of the battery cell after sintering; when spherical isolation powder is used, it can reduce friction and increase sliding between the battery cells when the battery cells shrink during sintering, thereby avoiding defects such as scratches; Irregular morphology of isolation powder has poor sliding effect, and is prone to form scratches on the electrolyte surface of the battery cell when subjected to pressure from a weight plate.

[0094] Examples 8 to 9 and Comparative Examples 23 to 25

[0095] The method of Example 1 was followed, except that the thickness of the isolation powder layer was adjusted. The state of the half-cell obtained is shown in Table 4.

[0096] Table 4

[0097]

[0098] As can be seen from Table 4, the thickness of the isolation powder will also have a significant impact on the sintering effect of the half-cell. The main function of the isolation powder is to separate the two battery electrolyte layers to prevent them from sticking together at high temperatures. When there is no isolation powder, the two batteries will stick together directly after sintering and it is difficult to separate them; when the isolation powder spraying thickness is thin (less than 40μm), there is little isolation powder between the battery cells, the coverage effect is poor, and local adhesion will occur, causing damage to the electrolyte; when the isolation powder spraying thickness is thick (greater than 60μm), there is more isolation powder between the battery cells, and the isolation powder will accumulate during the battery sintering and shrinkage process, which will cause local dent defects on the surface of the battery cell; only when the isolation powder spraying thickness is 40-60μm, its thickness is moderate, the isolation effect is sufficient and there is no accumulation, and the surface of the half-cell is smooth and flat without adhesion.

[0099] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a planar SOFC half-cell, characterized in that: The following steps are involved: (1) preparing a planar SOFC half-cell green body comprising an anode support layer, an anode functional layer, and an electrolyte layer, and then placing the planar SOFC half-cell green body in a mold for debinding to obtain a half-cell debinding green body; (2) stacking the electrolyte layers of two half-cell stripping blanks relative to each other and adding isolation powder between the two electrolyte layers to form a symmetrical sintered unit; (3) placing the symmetrical sintering unit between two support plates for weight sintering; (4) The sintered symmetrical sintered unit is taken out, and the isolation powder on the surface of the electrolyte layer is removed to obtain a planar SOFC half-cell.

2. The method for preparing a planar SOFC half-cell according to claim 1, characterized in that: The isolation powder is at least one of alumina powder and zirconium oxide powder; Preferably, the particle size of the isolation powder is 20 to 40 μm; Preferably, the added thickness of the isolation powder is 40-60 μm.

3. The method for preparing a planar SOFC half-cell according to claim 1, characterized in that: The debinding temperature is 500-1200° C., the heating rate is 0.1-5° C. / min, and the heat preservation time is 1-5 hours.

4. The method for preparing a planar SOFC half cell according to any one of claims 1 to 3, characterized in that: The mold is a porous ceramic carrier, including a porous ceramic bottom plate and a porous ceramic upper plate, and ceramic pillars are arranged at four corners of the porous ceramic upper plate.

5. The method for preparing a planar SOFC half-cell according to claim 4, characterized in that: The porosity of the porous ceramic carrier is 20-30%; Preferably, the height of the ceramic pillar is higher than the thickness of the planar SOFC half-cell green body; Preferably, the gap between the porous ceramic upper plate and the flat SOFC half-cell green body is 0.3-0.5 mm.

6. The method for preparing a planar SOFC half cell according to any one of claims 1 to 3, characterized in that: The thickness of the anode support layer is 300 to 1500 μm; Preferably, the thickness of the anode functional layer is 1 to 50 μm; Preferably, the electrolyte layer has a thickness of 1 to 50 μm.

7. The method for preparing a planar SOFC half-cell according to claim 1, characterized in that: The material of the setter plate is at least one of zirconium oxide, aluminum oxide and silicon carbide; Preferably, the pressure sintering temperature is 1300-1500° C., the heating rate is 0.1-5° C. / min, and the holding time is 1-10 h.

8. The method for preparing a planar SOFC half-cell according to claim 1, characterized in that: The isolation powder is removed by at least one of air gun blowing, grinding, and ultrasonic cleaning.

9. A method for preparing a planar SOFC full cell, characterized in that: The following steps are involved: (1) Preparing a planar SOFC half cell according to the method described in any one of claims 1 to 8; (2) preparing a barrier layer on the electrolyte side of a planar SOFC half-cell and then sintering it; (3) A cathode layer is prepared on the barrier layer, and then sintered to obtain a planar SOFC full cell.

10. The method for preparing a planar SOFC full cell according to claim 9, characterized in that: The thickness of the barrier layer is 1 to 50 μm; Preferably, the sintering temperature of the barrier layer is 1000-1400°C, the heating rate is 0.1-5°C / min, and the holding time is 1-10h; Preferably, the thickness of the cathode layer is 1 to 50 μm; Preferably, the sintering temperature of the cathode layer is 1000-1400° C., the heating rate is 0.1-5° C. / min, and the insulation time is 1-10 h.

Images