Button type solid oxide fuel half cell and preparation method thereof

Abstract

The invention discloses a button type solid oxide fuel half cell and a preparation method thereof, and belongs to the technical field of solid oxide fuel cells. According to the preparation method of the button type solid oxide fuel half-cell, the thickness of the electrolyte layer can be accurately controlled, by introducing a tape casting process, YSZ electrolyte tape casting slurry is uniformly laid on a tape casting plate with the controllable thickness, and by combining a pressing process of anode powder, tight combination of an anode support and the electrolyte layer is achieved, and the production efficiency of the button type solid oxide fuel half-cell is improved. The problem that the thickness of an electrolyte layer prepared by a traditional dry pressing sintering method is too large is solved, and the compactness and the stability of the multilayer structure of the button type solid oxide fuel half-cell are ensured through sintering.

Description

Technical Field

[0001] This invention relates to the field of solid oxide fuel cell technology, specifically to a button-type solid oxide fuel cell and its preparation method. Background Technology

[0002] Solid oxide fuel cells (SOFCs), as a type of all-solid-state fuel cell, have the core advantage of directly converting the chemical energy of fuel into electrical energy. Compared with traditional fuel cells, SOFCs have two significant characteristics: first, they do not rely on precious metal catalysts, which greatly reduces production costs; second, they have a wide operating temperature range (600 ℃~1000 ℃), giving them advantages such as wide fuel adaptability and high waste heat utilization. A typical SOFC structure consists of three parts: electrolyte, anode, and cathode. The electrolyte material is often yttrium oxide-stabilized zirconium oxide (YSZ), while the anode commonly uses nickel-yttrium oxide-stabilized zirconium oxide (Ni-YSZ) cermet.

[0003] In the development of SOFCs, the preparation process of the electrolyte layer directly affects battery performance. The electrolyte layer prepared by the traditional dry pressing and sintering method has the problem of excessive thickness, resulting in excessively long ion transport paths, which seriously affects the battery's current density and power density output. Summary of the Invention

[0004] The purpose of this invention is to provide a button-type solid oxide fuel cell and its preparation method, so as to overcome the problem of insufficient battery performance caused by excessively thick electrolyte layer in the prior art.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution: This invention provides a method for preparing a button-type solid oxide fuel cell, comprising the following steps: S1. YSZ, dioctyl phthalate, triethanolamine, polyethylene glycol, polyvinyl butyral, and ethanol are first ground to obtain YSZ electrolyte casting slurry; NiO, YSZ, polyvinyl butyral, and starch are used as anode raw materials, and ethanol is used as the grinding medium to perform a second grinding, drying, and sieving on the anode raw materials to obtain NiO-YSZ anode powder. S2. Spread the YSZ electrolyte casting slurry evenly on the casting plate with controllable thickness, and cut it after drying to obtain YSZ casting layer discs. S3. Place the NiO-YSZ anode powder on a YSZ cast layer disc, press it to obtain a NiO-YSZ anode support / YSZ electrolyte bilayer film green body, sinter and cool to room temperature to obtain a button-type solid oxide fuel cell.

[0006] A further improvement of the present invention is that the mass ratio of YSZ, dioctyl phthalate, triethanolamine, polyethylene glycol, polyvinyl butyral, and ethanol is 100:4:4:4:8:152.

[0007] A further improvement of this invention is that the thickness of the cast plate is controlled in the following way: Thick aluminum foil tape is attached to both sides of a smooth glass plate as a casting thickness control layer for the casting plate. The thickness of the casting thickness control layer is controlled by controlling the thickness of the aluminum foil tape.

[0008] A further improvement of the present invention is that the thickness of the casting thickness control layer is 100~200 μm.

[0009] A further improvement of the present invention is that the first grinding is carried out using a planetary ball mill with a grinding speed of 500 r / min and a grinding time of 2 h; the second grinding is carried out using a planetary ball mill with a grinding speed of 500 r / min and a grinding time of 24 h.

[0010] A further improvement of the present invention is that the diameter of the YSZ cast layer disc is 20 mm.

[0011] A further improvement of the present invention is that the mass ratio of NiO, YSZ, polyvinyl butyral and starch is 6:4:0.3:1.5.

[0012] A further improvement of the present invention is that, in step S3, the pressing is performed using a tableting mold, with a pressure of 400 MPa applied at room temperature for 60 s; the sintering temperature is 1400 ℃ for 2 h, and the heating rate is 1 ℃ / min.

[0013] A further improvement of the present invention is that the NiO-YSZ anode support thickness of the button-type solid oxide fuel cell is 215 μm; and the YSZ electrolyte thickness of the button-type solid oxide fuel cell is 17~30 μm.

[0014] The present invention also provides a button-type solid oxide fuel cell, which is prepared by the above-described method for preparing a button-type solid oxide fuel cell.

[0015] Compared with the prior art, the positive and progressive effects of the present invention are as follows: The method for preparing a button-type solid oxide fuel cell provided by this invention can precisely control the thickness of the electrolyte layer. By introducing a casting process, YSZ electrolyte casting slurry is evenly spread on a casting plate with controllable thickness. Combined with the pressing process of anode powder, a tight bond between the anode support and the electrolyte layer is achieved. This solves the problem of excessive thickness of the electrolyte layer prepared by the traditional dry pressing and sintering method. Furthermore, sintering ensures the density and stability of the multilayer structure of the button-type solid oxide fuel cell. Attached Figure Description

[0016] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0017] Figure 1 This is a schematic diagram of the preparation method of the button-type solid oxide fuel cell of the present invention.

[0018] Figure 2 This is a SEM image of the electrolyte-anode support interface of the button-type solid oxide fuel cell of the present invention.

[0019] Figure 3 This is a SEM image of the button-type solid oxide fuel cell half-cell prepared in Example 1 of the present invention.

[0020] Figure 4 This is a SEM image of the button-type solid oxide fuel cell half-cell prepared in Example 2 of the present invention.

[0021] Figure 5 The IVP curve of the full cell assembled from the button-type solid oxide fuel cell half cell prepared in Example 2 of the present invention is shown in the fuel 10% C3H8-Ar.

[0022] Figure 6 The IVP curve of a full cell assembled from the button-type solid oxide fuel cell half cell prepared in Example 1 of the present invention is shown in the fuel 10% C3H8-Ar. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This is an explanation of the present invention and not a limitation thereof.

[0029] A method for preparing a button-type solid oxide fuel cell includes the following steps: S1. YSZ, dioctyl phthalate, triethanolamine, polyethylene glycol, polyvinyl butyral, and ethanol are first ground to obtain YSZ electrolyte casting slurry; NiO, YSZ, polyvinyl butyral, and starch are used as anode raw materials, and ethanol is used as the grinding medium to perform a second grinding, drying, and sieving on the anode raw materials to obtain NiO-YSZ anode powder. S2. Spread the YSZ electrolyte casting slurry evenly on the casting plate with controllable thickness, and cut it after drying to obtain YSZ casting layer discs. S3. Place the NiO-YSZ anode powder on a YSZ cast layer disc, press it to obtain a NiO-YSZ anode support / YSZ electrolyte bilayer film green body, sinter and cool to room temperature to obtain a button-type solid oxide fuel cell.

[0030] Compared to existing technologies, the thickness of the electrolyte layer prepared by the traditional dry pressing method is difficult to control precisely, and the interfacial bonding strength between the anode and the electrolyte layer is relatively low. This method achieves uniform film formation of the electrolyte layer through a casting process, combined with stepwise grinding and pressing processes, thereby improving interlayer bonding. This method can produce a dense electrolyte layer with controllable thickness, effectively shortening the ion transport path and improving the battery's current output efficiency. Simultaneously, the tight bonding between the anode support and the electrolyte layer enhances the overall structural mechanical stability and reduces the risk of interfacial failure during high-temperature operation.

[0031] The thickness control layer of the cast plate refers to the limitation of the slurry spreading gap by attaching tin foil tape of a specific thickness. For example, the thickness of the cast layer can be precisely adjusted by adjusting the thickness of the tape. The pressure applied in the pressing step can form a tight contact between the anode powder and the electrolyte layer, reducing interfacial porosity. The high-temperature treatment during sintering helps to remove organic binders and promote the densification of ceramic particles. After the YSZ electrolyte cast slurry is formed into a thin layer through the casting process, it is pressed together with the anode powder to form a double-layer structure. The two layers are then bonded together at high temperature through sintering. The uniform spreading characteristics of the casting process can avoid the uneven thickness problem caused by the traditional dry pressing method. Stepwise grinding and sieving ensure that the particle size distribution of the anode powder is uniform, thereby improving the density of the green body after pressing. The slow heating during sintering can reduce thermal stress and prevent interlayer cracking.

[0032] Preferably, the mass ratio of YSZ, dioctyl phthalate, triethanolamine, polyethylene glycol, polyvinyl butyral, and ethanol is 100:4:4:4:8:152.

[0033] By combining YSZ with dioctyl phthalate, triethanolamine, and polyethylene glycol in a specific mass ratio in an ethanol solvent to form a slurry system with suitable rheological properties, the synergistic effect of plasticizers and binders is ensured. This maintains the fluidity of the slurry during casting and guarantees the mechanical integrity of the film after drying. The amount of polyvinyl butyral is optimized to form a continuous film while avoiding excessive amounts that would lead to residual carbon impurities after sintering. The ratio of triethanolamine to polyethylene glycol balances the requirements for particle dispersion and bonding strength, ultimately giving the cast slurry good film-forming properties and sintering activity. By precisely controlling the proportions of each component, a stable composite system is formed between organic additives and inorganic materials, overcoming problems such as slurry delamination and cracking, while ensuring the density of the electrolyte layer after sintering. Through the above technical solutions, this application achieves synergistic effects among the components of the YSZ electrolyte slurry, significantly improving the controllability of the casting process, effectively reducing the generation of micro-defects such as pinholes and cracks in the film, and providing a reliable foundation for the preparation of high-performance solid oxide fuel cell half-cells.

[0034] Preferably, the thickness of the cast plate is controlled in the following ways: Thick aluminum foil tape is attached to both sides of a smooth glass plate as a casting thickness control layer for the casting plate. The thickness of the casting thickness control layer is controlled by controlling the thickness of the aluminum foil tape.

[0035] Two equal-width strips of tin foil tape are applied parallel to both sides of a glass plate, with the tape thickness matching the target cast layer thickness. When the slurry is poured onto the glass plate surface, a scraper smooths the slurry along the tape surface. The raised edges formed by the tape restrict the slurry's outward diffusion, ensuring that the thickness of the electrolyte layer after drying is consistent with the tape thickness. By using physical limiting instead of traditional mold pressing, thickness deviations caused by slurry shrinkage or insufficient mold precision are avoided. Furthermore, using tin foil tape as a thickness control layer allows for quick adjustment of the forming dimensions simply by changing tapes of different thicknesses, simplifying the process. The way the tape is applied to the glass plate also prevents edge burrs caused by slurry penetration, improving the surface smoothness of the electrolyte layer. Through this technical solution, this application achieves precise control of the electrolyte layer thickness during the casting process, solving the problem of excessive thickness caused by differences in slurry flowability in traditional methods. This provides a fundamental guarantee for preparing an anode support / electrolyte bilayer film with stable interfacial bonding, while reducing equipment investment and operational complexity.

[0036] Preferably, the thickness of the casting thickness control layer is 100~200 μm.

[0037] Preferably, the first grinding is carried out using a planetary ball mill with a grinding speed of 500 r / min and a grinding time of 2 h; the second grinding is carried out using a planetary ball mill with a grinding speed of 500 r / min and a grinding time of 24 h.

[0038] During the preparation of the electrolyte slurry, a planetary ball mill is run at a specific speed for two hours to achieve molecular-level dispersion of YSZ powder with organic additives such as binders and plasticizers, forming a casting slurry with appropriate viscosity. In the anode powder treatment stage, the same type of equipment is used but the grinding time is extended to twenty-four hours, which promotes the formation of a uniform composite structure of NiO and YSZ powder with the assistance of polyvinyl butyral. At the same time, starch, as a pore-forming agent, is fully coated in the interparticle gaps. The resulting slurry and powder have ideal rheological properties and sintering activity, providing the basic conditions for subsequent casting and co-sintering. By setting different grinding time parameters, the problem of component segregation caused by insufficient grinding of anode raw materials is avoided while ensuring complete dissolution of organic matter in electrolyte slurry. This effectively solves the technical contradiction that traditional grinding processes cannot balance the dispersion of electrolyte slurry and the uniformity of anode powder, enabling the YSZ cast layer to form a defect-free and dense structure. At the same time, it ensures that the NiO-YSZ anode has an optimized pore distribution and three-phase interface. The half-cell prepared in this way exhibits a stable interlayer bonding state after sintering, providing reliable mechanical support and electrochemical performance basis for subsequent battery stacking.

[0039] Preferably, the diameter of the YSZ cast layer disc is 20 mm.

[0040] Preferably, the mass ratio of NiO, YSZ, polyvinyl butyral, and starch is 6:4:0.3:1.5.

[0041] Preferably, in step S3, the pressing is performed using a tableting mold, with a pressure of 400 MPa applied at room temperature for 60 s; the sintering temperature is 1400 ℃ for 2 h, and the heating rate is 1 ℃ / min.

[0042] Preferably, the NiO-YSZ anode support thickness of the button-type solid oxide fuel cell is 215 μm; the YSZ electrolyte thickness of the button-type solid oxide fuel cell is 17~30 μm.

[0043] Based on the same inventive concept, the present invention provides a button-type solid oxide fuel cell, which is prepared by the above-described method for preparing a button-type solid oxide fuel cell.

[0044] The button-type solid oxide fuel cell prepared by the method of the present invention consists of an electrolyte, an anode, and a cathode. The anode is a NiO-YSZ anode support with a porous structure, and the electrolyte is a dense YSZ electrolyte. The YSZ electrolyte is prepared by casting YSZ slurry on a smooth glass plate covered with 100-200 μm thick tin foil anti-permeability tape. After air drying, it is cut into 20 mm round pieces and co-pressed with anode powder at 400 MPa. Then, the green blank is sintered at 1400 °C for 2 h to obtain the button-type solid oxide fuel cell. Finally, a barrier layer and a cathode layer are sprayed to form a complete single cell.

[0045] The thickness of the YSZ cast layer can be determined by the thickness of the tin foil anti-permeation tape. A thinner tape thickness is more beneficial for preparing high-oxygen-conductivity SOFC (Solid Oxide Fuel Cell) single cells. This invention, by preparing the YSZ cast layer, can obtain a dense and thin electrolyte layer. Compared with existing technologies, the advantages of this invention are: the cast-layer device, made from readily available and economical materials, is suitable for laboratory operation, avoiding the use of large-scale cast-layer machines; button-type solid oxide half-cells can be prepared by co-pressing the YSZ cast layer with NiO-YSZ anode powder using a dry pressing method; the prepared button-type solid oxide half-cell (anode support / electrolyte bilayer membrane) has a flat cross-section without breakage; and the full cell assembled using this button-type solid oxide fuel cell exhibits excellent electrochemical performance.

[0046] Example 1 See Figure 1Step 1: Place 10 g YSZ, 0.4 g dioctyl phthalate, 0.4 g triethanolamine, 0.4 g polyethylene glycol, 0.8 g polyvinyl butyral, and 15.2 g ethanol in a planetary ball mill and ball mill at 500 r / min for 2 h to obtain YSZ electrolyte casting slurry; use 6 g NiO, 4 g YSZ, 0.3 g polyvinyl butyral, and 1.5 g starch as anode raw materials and ethanol as grinding medium in a planetary ball mill and grind at 500 r / min for 24 h, then pass through a 400 mesh sieve to obtain NiO-YSZ anode powder; Step 2: Spread the prepared YSZ electrolyte casting slurry evenly on the casting board and spread it evenly with a scraper. The casting board is made of smooth glass as the base plate. 100 μm tin foil anti-permeability tape is attached to both sides of the smooth glass as the casting thickness control layer of the casting board. After the YSZ electrolyte casting slurry spread on the casting board has dried naturally in the shade, demold it and cut it into YSZ casting layer discs with a diameter of 20 mm using a hole cutter for later use. Step 3: Place the YSZ cast layer disc into a pressing mold with a diameter of 20 mm, and simultaneously spread 0.25 g of NiO-YSZ anode powder evenly in the pressing mold. Apply a pressure of 400 MPa at room temperature to press and shape the material, and hold for 60 s to obtain a NiO-YSZ anode support / YSZ electrolyte bilayer membrane green cell. Sinter the upper NiO-YSZ anode support / YSZ electrolyte bilayer membrane green cell at 1400 ℃ for 2 h, and then allow it to cool naturally to room temperature at a heating rate of 1 ℃ / min to obtain a button-type solid oxide fuel cell.

[0047] Cross-sectional scanning electron microscope image of the button-type solid oxide fuel cell prepared using this embodiment, see [link to image]. Figure 2 and Figure 3 The YSZ electrolyte in the button-type solid oxide fuel cell has a thickness of 17 μm and is a dense structure, while the NiO-YSZ anode support in the button-type solid oxide fuel cell has a thickness of 215 μm and is a porous structure. The prepared button-type solid oxide fuel cell exhibits a higher current density. See [link to documentation]. Figure 6 .

[0048] Example 2 The only difference from Example 1 is that the thickness of the tin foil anti-permeability tape in step two is 200 μm, and the thickness of the YSZ electrolyte in the prepared button-type solid oxide fuel cell is 30 μm. Figure 4 The current density of the prepared button-type solid oxide fuel cell is shown in [reference]. Figure 5 .

[0049] As can be seen from Examples 1 and 2, the thinner the tin foil anti-permeability tape and the thinner the YSZ, the better the oxygen ion transport and the better the overall electrical performance of the battery.

[0050] Meanwhile, the preparation method described in this invention is relatively simple and inexpensive in terms of casting tools, and it saves more space than larger casting machines. After cutting the cast sheet, it is co-pressed with the anode dry powder, which is more suitable for small muffle furnaces in the laboratory and is convenient to operate.

[0051] Finally, it should be noted that the embodiments listed above are merely one or more specific manifestations of the technical solution of this invention. Their purpose is to clearly illustrate the concept, principle, and application of this invention through specific examples, and is by no means intended to limit the scope of protection of this invention to these specific embodiments. In fact, the true value of this invention lies in its proposed technical ideas and innovations, rather than its manifestations or implementation methods.

[0052] For those skilled in the art, after thoroughly reading and understanding the technical solution of this invention, they are fully capable of making various changes, modifications, or equivalent substitutions to the specific implementation of the invention based on their own professional knowledge and skills. These changes may include, but are not limited to: adjusting the range of technical parameters, optimizing the algorithm flow to improve efficiency, and replacing some technical components to achieve better compatibility or reduce costs. As long as these modified technical solutions substantially retain the technical features claimed by the original invention, that is, they can still achieve the core functions and effects of this invention, then these changes should be considered to fall within the scope of protection of the pending claims of this invention.

[0053] Furthermore, with the continuous progress and development of technology, new technical means and methods are constantly emerging, which provides ample space for further improvement and perfection of this invention. Therefore, the scope of protection of this invention should also include reasonable and foresightful improvements and extensions based on existing technology. As long as these improvements and extensions do not depart from the basic principles and core concepts of this invention, they should be considered equivalents of this invention and are equally protected by patent rights.

Claims

1. A method for producing a solid oxide fuel cell button, characterized by, The method comprises the following steps: S1, first grinding YSZ, dioctyl phthalate, triethanolamine, polyethylene glycol, polyvinyl butyral and ethanol to obtain YSZ electrolyte casting slurry; taking NiO, YSZ, polyvinyl butyral and starch as anode raw materials, and taking ethanol as grinding medium, the anode raw materials are sequentially subjected to second grinding, drying and sieving to obtain NiO-YSZ anode powder; S2, uniformly laying the YSZ electrolyte casting slurry on a casting plate with controllable thickness, and cutting after drying to obtain YSZ casting layer wafer; S3, placing the NiO-YSZ anode powder on the YSZ casting layer wafer, and pressing to obtain a NiO-YSZ anode support / YSZ electrolyte double-layer film green body, which is sintered and cooled to room temperature to obtain a button-type solid oxide fuel half-cell.

2. The method of claim 1, wherein the method further comprises the step of: The mass ratio of YSZ, dioctyl phthalate, triethanolamine, polyethylene glycol, polyvinyl butyral and ethanol is 100:4:4:4:8:

152. ​ 3. The method of claim 1, wherein the method further comprises: forming a plurality of solid oxide fuel cell layers on the substrate; and forming a plurality of interconnect layers on the substrate. The thickness of the casting plate is controlled by the following method: The smooth glass plate is pasted with tin paper adhesive tape with thickness on both sides as the casting thickness control layer of the casting plate, and the thickness of the casting thickness control layer is controlled by controlling the thickness of the tin paper adhesive tape.

4. A method of making a solid oxide fuel cell according to claim 3, wherein The thickness of the casting thickness control layer is 100-200 μm.

5. The method of claim 1, wherein the method further comprises: The first grinding adopts a planetary ball mill, the grinding speed is 500 r / min, and the grinding time is 2 h; the second grinding adopts a planetary ball mill, the grinding speed is 500 r / min, and the grinding time is 24 h.

6. The method of claim 1, wherein the method further comprises: The diameter of the YSZ casting layer wafer is 20 mm.

7. The method of claim 1, wherein the method further comprises the step of: The mass ratio of NiO, YSZ, polyvinyl butyral and starch is 6:4:0.3:1.

5. ​ 8. The method of claim 1, wherein the method further comprises: In step S3, the pressing adopts a tablet pressing mold, the pressure is applied at room temperature at 400 MPa for 60 s; the sintering temperature is 1400℃, the time is 2 h, and the heating rate is 1℃ / min.

9. The method of claim 1, wherein the method further comprises: The thickness of the NiO-YSZ anode support of the button-type solid oxide fuel half-cell is 215 μm; the thickness of the YSZ electrolyte of the button-type solid oxide fuel half-cell is 17-30 μm.

10. A solid oxide fuel button half-cell, characterized by Prepared by the method of any one of claims 1-9. Prepared by the method of any one of claims 1-9.

Images