Electrolyte-supported single cell and preparation method thereof

Abstract

The invention provides an electrolyte-supported monocell and a preparation method thereof, and belongs to the technical field of fuel cells. A first electrolyte transition layer is arranged between an electrolyte layer and an anode functional layer, and a second electrolyte transition layer is arranged between the electrolyte layer and a cathode functional layer; gradient supporting structures are formed between the electrolyte layer and the anode functional layer and between the electrolyte layer and the cathode functional layer; wherein the first electrolyte transition layer comprises at least two first composite gradient supporting layers, and the second electrolyte transition layer comprises at least two second composite gradient supporting layers; in the direction from the electrolyte layer to the anode functional layer and the cathode functional layer, the porosity of the first composite gradient supporting layer and the porosity of the second composite gradient supporting layer are sequentially increased, so that the anode-electrolyte-cathode interface contact is improved, the ion conduction path is optimized, the resistance is reduced, and meanwhile, the relatively high mechanical strength is kept; and the reliability and the long service life of the electrolyte-supported SOFC single cell are improved.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more specifically, to an electrolyte-supported single cell and its preparation method. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are efficient and environmentally friendly energy conversion devices that directly convert chemical energy into electrical energy. Traditional SOFCs typically employ single cells with anode-supported, cathode-supported, or electrolyte-supported structures. Among these, electrolyte-supported SOFCs offer advantages such as high mechanical strength and good thermal shock resistance. Electrolyte-supported SOFC cells usually operate in a medium-to-high temperature environment of 800-1000℃. This high temperature condition leads to a temperature gradient within the cell, resulting in uneven temperature distribution. Due to the differences in the coefficients of thermal expansion among the electrolyte, cathode, and anode components in the single cell structure, stress and strain distribution becomes uneven. The anode and cathode materials, electrolyte, and connectors undergo varying degrees of volume shrinkage or expansion at different temperatures, causing the anode and cathode materials to peel off from the electrolyte. Furthermore, the brittleness of ceramic materials makes the single cell susceptible to irreversible damage such as deformation, delamination, cracks, and even structural breakage, ultimately affecting the SOFC's power generation efficiency and significantly impacting its service life and safety performance.

[0003] The commonly used anode material is NiO-YSZ, the electrolyte material is YSZ, and the cathode material is LSCF. These three materials differ in their coefficients of thermal expansion, chemical compatibility, and mechanical properties. Under high-temperature conditions (>800℃), thermal stress, element diffusion, second phase formation, and cracking occur at the interface, leading to increased interfacial resistance, decreased interfacial stability, and ultimately, battery failure. Therefore, improving the anode / electrolyte / cathode interface contact, enhancing interfacial stability, and reducing interfacial resistance are crucial for the long-term operational stability of electrolyte-supported SOFC single cells. Furthermore, reducing electrolyte resistance while maintaining mechanical strength is also key to improving the operating efficiency of electrolyte-supported SOFC single cells.

[0004] In summary, current electrolyte-supported solid oxide fuel cells suffer from several drawbacks. Insufficient mechanical strength of the electrolyte material makes them prone to cracking or breakage under thermal cycling or mechanical stress at high temperatures, affecting battery reliability and lifespan. Additionally, the high interfacial resistance between the electrolyte and the cathode and anode increases the battery's internal resistance, leading to reduced output performance.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] In view of the above problems, the purpose of this invention is to provide an electrolyte-supported single cell and its preparation method, so as to solve the problems in the prior art where electrolyte-supported solid oxide fuel cells are prone to cracking or breakage under thermal cycling or mechanical stress at high temperature due to insufficient mechanical strength of the electrolyte material, which affects the reliability and life of the cell, and the problem that the high interface resistance between the electrolyte and the cathode and anode increases the internal resistance of the cell, resulting in reduced output performance.

[0007] The electrolyte-supported single cell provided by this invention includes an electrolyte layer, an anode functional layer and a cathode functional layer respectively disposed on the front and back sides of the electrolyte layer; wherein,

[0008] A first electrolyte transition layer is disposed between the electrolyte layer and the anode functional layer; the first electrolyte transition layer is composed of the material of the anode functional layer and the material of the electrolyte layer, and the first electrolyte transition layer includes at least two first composite gradient support layers; in the direction from the electrolyte layer to the anode functional layer, the porosity of the first composite gradient support layers increases sequentially.

[0009] A second electrolyte transition layer is provided between the electrolyte layer and the cathode functional layer; the second electrolyte transition layer is composed of the material of the cathode functional layer and the material of the electrolyte layer, and the second electrolyte transition layer includes at least two second composite gradient support layers; in the direction from the electrolyte layer to the cathode functional layer, the porosity of the second composite gradient support layers increases sequentially.

[0010] Furthermore, a preferred embodiment is that the material of the anode functional layer is NiO-Zr. 1-x Y x O 2-δ NiO-Zr 1-x Sc x O 2-δ NiO-Ce 1-x Gd x O2-δ, NiO-Ce 1-x Sm x Any one of O2-δ or at least two mixed in any proportion.

[0011] Furthermore, a preferred embodiment is that the material of the cathode functional layer is La. 1-x Sr x MnO 3-δ La 1-x Sr x Co 1- y Fe y O 3-δ 、Sm 0.5 Sr 0.5 CoO3-δ Ba 0.5 Sr 0.5 Co 0.5 Fe 0.2 O 3-δ Any one of them or at least two mixed in any proportion.

[0012] Furthermore, a preferred embodiment is that the electrolyte layer is made of Zr. 1-x Y x O 2-δ Zr 1-x Sc x O 2-δ Ce 1-x Gd x O 2-δ Ce 1-x Sm x Any one of O2-δ or at least two mixed in any proportion.

[0013] Furthermore, in a preferred embodiment, the porosity of the anode functional layer is 20-40%; the porosity of the cathode functional layer is 20-40%; the porosity of the electrolyte layer is 0%; the porosity of the first composite gradient support layer is 1-30%; and the porosity of the second composite gradient support layer is 1-30%.

[0014] Furthermore, a preferred embodiment is that the thickness of the anode functional layer is 5-25 μm.

[0015] Furthermore, a preferred embodiment is that the thickness of the cathode functional layer is 5-75 μm.

[0016] Furthermore, a preferred embodiment is that the thickness of the electrolyte layer is 10-100 μm; and / or, the thickness of the first electrolyte transition layer is 5-50 μm; and / or, the thickness of the second electrolyte transition layer is 5-50 μm.

[0017] The method for preparing the electrolyte-supported single cell as described above, provided by the present invention, is characterized by comprising the following steps:

[0018] Based on the determined material composition of the electrolyte layer, the anode functional layer, and the cathode functional layer, slurries for the electrolyte layer, the anode functional layer, and the cathode functional layer are prepared accordingly.

[0019] According to the preset porosity of each first composite gradient support layer, the slurry of the anode functional layer and the slurry of the electrolyte layer are mixed in a certain proportion to obtain the slurry of the first electrolyte transition layer; and according to the preset porosity of each second composite gradient support layer, the slurry of the cathode functional layer and the slurry of the electrolyte layer are mixed in a certain proportion to obtain the slurry of the second electrolyte transition layer.

[0020] According to the preset thickness of the electrolyte layer, a wet film of the electrolyte layer is prepared by casting the slurry of the electrolyte layer, and the wet film of the electrolyte layer is subjected to a first row of adhesive sintering treatment to obtain the electrolyte layer;

[0021] The paste of the first electrolyte transition layer is screen-printed onto the front side of the electrolyte layer, and after a first drying process, the first electrolyte transition layer is formed on the front side of the electrolyte layer.

[0022] The paste of the anode functional layer is screen-printed onto the surface of the first electrolyte transition layer. After a second drying process, a second stripping sintering process is performed to obtain a half cell.

[0023] The paste of the second electrolyte transition layer is screen-printed onto the reverse side of the electrolyte layer of the half cell, and after a third drying process, the second electrolyte transition layer is formed on the reverse side of the electrolyte layer of the half cell.

[0024] The paste of the cathode functional layer is screen-printed onto the surface of the second electrolyte transition layer. After a fourth drying process, a third stripping sintering process is performed to obtain an electrolyte-supported single cell.

[0025] Furthermore, a preferred embodiment is that, during the process of mixing the slurry of the anode functional layer and the slurry of the electrolyte layer in a certain proportion according to the preset porosity of each first composite gradient support layer to obtain the slurry of the first electrolyte transition layer,

[0026] The slurry of the first electrolyte transition layer includes the slurry of each first composite gradient support layer;

[0027] In the direction from the electrolyte layer to the anode functional layer, the proportion of the anode functional layer slurry in the slurry of the first composite gradient support layer gradually increases.

[0028] Furthermore, a preferred embodiment is that, during the process of mixing the slurry of the cathode functional layer and the slurry of the electrolyte layer in a certain proportion according to the preset porosity of each second composite gradient support layer to obtain the slurry of the second electrolyte transition layer,

[0029] The slurry of the second electrolyte transition layer includes the slurry of each second composite gradient support layer;

[0030] In the direction from the electrolyte layer to the cathode functional layer, the proportion of the cathode functional layer slurry in the slurry of the second composite gradient support layer gradually increases.

[0031] In addition, a preferred embodiment is that the temperature of the first debinding sintering treatment is 1450-1600℃ and the debinding sintering time is 3-6h.

[0032] Furthermore, a preferred embodiment is that during the process of screen printing the paste of the first electrolyte transition layer onto the front side of the electrolyte layer and performing a first drying treatment to form the first electrolyte transition layer on the front side of the electrolyte layer,

[0033] The paste of the first electrolyte transition layer is screen-printed onto the front side of the electrolyte layer in 3-5 passes;

[0034] The first drying process takes 5-25 minutes.

[0035] Furthermore, a preferred embodiment involves screen printing the paste of the anode functional layer onto the surface of the first electrolyte transition layer, followed by a second drying process and a second adhesive stripping and sintering process to obtain the half-cell.

[0036] The paste of the anode functional layer is screen-printed onto the surface of the first electrolyte transition layer in 1-3 passes;

[0037] The second drying process takes 5-25 minutes;

[0038] The temperature of the second debinding sintering treatment is 1200-1350℃, and the debinding sintering time is 2-4h.

[0039] Furthermore, a preferred embodiment is that, during the process of screen printing the paste of the second electrolyte transition layer onto the reverse side of the electrolyte layer of the half-cell, followed by a third drying process, the second electrolyte transition layer is formed on the reverse side of the electrolyte layer of the half-cell.

[0040] The slurry of the second electrolyte transition layer is screen-printed onto the reverse side of the electrolyte layer of the half-cell in 3-5 passes.

[0041] The third drying process takes 5-25 minutes.

[0042] Furthermore, a preferred embodiment involves screen printing the paste of the cathode functional layer onto the surface of the second electrolyte transition layer, followed by a fourth drying process, and then a third adhesive sintering process to obtain the electrolyte-supported single cell.

[0043] The paste of the cathode functional layer is screen-printed onto the surface of the second electrolyte transition layer in 1-3 passes;

[0044] The fourth drying process takes 5-25 minutes;

[0045] The temperature for the third debinding sintering process is 1100-1200℃, and the debinding sintering time is 2-4 hours.

[0046] As can be seen from the above technical solution, the electrolyte-supported single cell and its preparation method provided by the present invention, by setting a first electrolyte transition layer between the front side of the electrolyte layer and the anode functional layer; the first electrolyte transition layer includes at least two first composite gradient support layers; and the porosity of the first composite gradient support layers increases sequentially in the direction from the electrolyte layer to the anode functional layer, so as to form a gradient support structure between the electrolyte layer and the anode functional layer; by setting a second electrolyte transition layer between the back side of the electrolyte layer and the cathode functional layer; the second electrolyte transition layer includes at least two second composite gradient support layers; and the porosity of the second composite gradient support layers increases sequentially in the direction from the electrolyte layer to the cathode functional layer, so as to form a gradient support structure between the electrolyte layer and the cathode functional layer, thereby improving the interfacial contact between the anode functional layer, the electrolyte layer, and the cathode functional layer, optimizing the ion conduction path, reducing resistance, and maintaining high mechanical strength, thereby improving the reliability and long life of the electrolyte-supported SOFC single cell; and compared with the existing electrolyte-supported SOFC single cell, by reducing the interfacial resistance between the electrolyte layer and the cathode and anode functional layers, thereby reducing the internal resistance of the battery, the output performance can be improved.

[0047] To achieve the foregoing and related objectives, one or more aspects of the invention include the features that will be described in detail below. The following description and accompanying drawings illustrate certain exemplary aspects of the invention. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to encompass all such aspects and their equivalents. Attached Figure Description

[0048] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings, and with a more complete understanding of the invention.

[0049] Figure 1 This is a schematic diagram of the structure of an electrolyte-supported single cell according to an embodiment of the present invention;

[0050] Figure 2 This is a diagram showing the relationship between the first electrolyte transition layer, the second electrolyte transition layer, and the electrolyte layer according to an embodiment of the present invention.

[0051] Figure 3 This is a schematic diagram of the structure of the first electrolyte transition layer according to an embodiment of the present invention;

[0052] Figure 4This is a schematic diagram of the structure of the second electrolyte transition layer according to an embodiment of the present invention;

[0053] Figure 5 This is a flowchart of a method for preparing an electrolyte-supported single cell according to an embodiment of the present invention.

[0054] In the attached figures, 1-electrolyte layer, 2-anode functional layer, 3-cathode functional layer, 4-first electrolyte transition layer, 41-first composite gradient support layer, 5-second electrolyte transition layer, 51-second composite gradient support layer.

[0055] In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation

[0056] In response to the aforementioned issues, in the existing technology, electrolyte-supported solid oxide fuel cells suffer from problems such as insufficient mechanical strength of the electrolyte material, which makes them prone to cracking or breakage under thermal cycling or mechanical stress at high temperatures, affecting battery reliability and lifespan; and high interfacial resistance between the electrolyte and the cathode and anode, which increases the battery's internal resistance and leads to reduced output performance. Therefore, an electrolyte-supported single cell and its preparation method are proposed.

[0057] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0058] To illustrate the electrolyte-supported single cell and its preparation method provided by the present invention Figure 1 The structure of an electrolyte-supported single cell according to an embodiment of the present invention is shown; Figure 2 The relationship between the first electrolyte transition layer, the second electrolyte transition layer, and the electrolyte layer according to an embodiment of the present invention is shown; Figure 3 The structure of the first electrolyte transition layer according to an embodiment of the present invention is shown; Figure 4 The structure of the second electrolyte transition layer according to an embodiment of the present invention is shown; Figure 5 A method flow diagram for preparing an electrolyte-supported single cell according to an embodiment of the present invention is shown.

[0059] like Figures 1 to 4 As shown in the figure, the electrolyte-supported single cell provided by the present invention includes an electrolyte layer 1, an anode functional layer 2 and a cathode functional layer 3 respectively disposed on the front and back sides of the electrolyte layer 1; wherein, a first electrolyte transition layer 4 is disposed between the electrolyte layer 1 and the anode functional layer 2; the first electrolyte transition layer 4 is composed of a composite of the material of the anode functional layer 2 and the material of the electrolyte layer 1, and the first electrolyte transition layer 4 includes at least two first composite gradient support layers 41; in the direction from the electrolyte layer 1 to the anode functional layer 2, the porosity of the first composite gradient support layers 41 increases sequentially;

[0060] A second electrolyte transition layer 5 is provided between the electrolyte layer 1 and the cathode functional layer 3. The second electrolyte transition layer 5 is composed of the material of the cathode functional layer 3 and the material of the electrolyte layer 1. The second electrolyte transition layer 5 includes at least two second composite gradient support layers 51. In the direction from the electrolyte layer 1 to the cathode functional layer 3, the porosity of the second composite gradient support layers 51 increases sequentially.

[0061] By providing a first electrolyte transition layer 4 between the front side of the electrolyte layer 1 and the anode functional layer 2, the first electrolyte transition layer 4 includes at least two first composite gradient support layers 41, and the porosity of the first composite gradient support layers 41 increases sequentially in the direction from the electrolyte layer 1 to the anode functional layer 2, thereby forming a gradient support structure between the electrolyte layer 1 and the anode functional layer 2. By providing a second electrolyte transition layer 5 between the back side of the electrolyte layer 1 and the cathode functional layer 3, the second electrolyte transition layer 5 includes at least two second composite gradient support layers 51, and the porosity of the second composite gradient support layers 51 increases sequentially in the direction from the electrolyte layer 1 to the cathode functional layer 3, thereby forming a gradient support structure between the electrolyte layer 1 and the cathode functional layer 3. This improves the interfacial contact between the anode functional layer, the electrolyte layer, and the cathode functional layer, optimizes the ion conduction path, reduces resistance, and maintains high mechanical strength, thereby improving the reliability and long lifespan of the electrolyte-supported SOFC single cell. Compared with existing electrolyte-supported SOFC single cells, the output performance is improved by reducing the interfacial resistance between the electrolyte layer and the cathode and anode functional layers, thereby reducing the internal resistance of the battery.

[0062] As a preferred embodiment of the present invention, the material of the anode functional layer is NiO-Zr. 1-x Y x O 2-δ NiO-Zr 1- x Sc x O 2-δ NiO-Ce 1-x Gd x O2-δ, NiO-Ce 1-x Sm x Any one of O2-δ or at least two mixed in any proportion.

[0063] It should be noted that, in the technical solution of this invention, the material of the anode functional layer is preferably, but not limited to, NiO-Zr. 1-x Y x O 2-δ (i.e., NiO-YSZ, where 0.1≤x≤0.2), NiO-Zr 1-x Sc x O 2-δ(i.e., NiO-ScSZ, where 0.08≤x≤0.11), NiO-Ce 1-x Gd x O2-δ (i.e., NiO-GDC, where 0.1≤x≤0.2), NiO-Ce 1-x Sm x Any one of O2-δ (i.e. NiO-SDC, where 0.1≤x≤0.2) or at least two of them mixed in any proportion.

[0064] As a preferred embodiment of the present invention, the material of the cathode functional layer is La. 1-x Sr x MnO 3-δ La 1-x Sr x Co 1- y Fe y O 3-δ 、Sm 0.5 Sr 0.5 CoO 3-δ Ba 0.5 Sr 0.5 Co 0.5 Fe 0.2 O 3-δ Any one of them or at least two mixed in any proportion.

[0065] It should be noted that, in the technical solution of this invention, the material of the cathode functional layer is preferably, but not limited to, La. 1- x Sr x MnO 3-δ (i.e., LSM), La 1-x Sr x Co 1-y Fe y O 3-δ (i.e., LSCF), Sm 0.5 Sr 0.5 CoO 3-δ (i.e. SSC), Ba 0.5 Sr 0.5 Co 0.5 Fe 0.2 O 3-δ Any one of (i.e., BSCF) or at least two of them mixed in any proportion.

[0066] As a preferred embodiment of the present invention, the electrolyte layer is made of Zr. 1-x Y x O 2-δ Zr 1-x Sc x O 2-δ Ce1- x Gd x O 2-δ Ce 1-x Sm x Any one of O2-δ or at least two mixed in any proportion.

[0067] It should be noted that, in the technical solution of this invention, the material of the electrolyte layer is preferably, but not limited to, Zr. 1-x Y x O 2-δ (i.e., YSZ, where 0.03≤x≤0.1), Zr 1-x Sc x O 2-δ (i.e., ScSZ, where 0.08≤x≤0.11), Ce 1-x Gd x O 2-δ (i.e., GDC, where 0.1≤x≤0.2), Ce 1-x Sm x O2-δ (i.e. SDC, where 0.1≤x≤0.2).

[0068] As a preferred embodiment of the present invention, the porosity of the anode functional layer is 20-40%; the porosity of the cathode functional layer is 20-40%; the porosity of the electrolyte layer is 0%; the porosity of the first composite gradient support layer is 1-30%; and the porosity of the second composite gradient support layer is 1-30%.

[0069] Specifically, in electrolyte-supported SOFC single cells, the anode and cathode functional layers have relatively high porosity, while the electrolyte layer has high density, typically with zero porosity. This leads to problems when the electrolyte layer directly contacts the anode and cathode functional layers in existing SOFC single cells. Due to differences in thermal expansion coefficients, chemical compatibility, and mechanical properties among these three layers, thermal stress, element diffusion, second phase formation, and cracking occur at the interface under high-temperature conditions (>800℃), resulting in increased interface resistance, reduced interface stability, and ultimately, battery failure. In this invention, by setting a first composite gradient support layer and a second composite gradient support layer, a gradient structure is introduced into the electrolyte layer, thereby improving the anode-electrolyte-cathode interface contact, optimizing the ion conduction path, reducing resistance, and maintaining high mechanical strength, thus improving the reliability and lifespan of the electrolyte-supported SOFC single cell.

[0070] As a preferred embodiment of the present invention, the thickness of the anode functional layer 2 is 5-25 μm.

[0071] As a preferred embodiment of the present invention, the thickness of the cathode functional layer 3 is 5-75 μm.

[0072] As a preferred embodiment of the present invention, the thickness of the electrolyte layer 1 is 10-100 μm; and / or, the thickness of the first electrolyte transition layer 4 is 5-50 μm; and / or, the thickness of the second electrolyte transition layer 5 is 5-50 μm.

[0073] It should be noted that: the thickness of the anode functional layer 2 is preferably, but not limited to, 5-25 μm; the thickness of the cathode functional layer 3 is preferably, but not limited to, 5-75 μm; the thickness of the electrolyte layer 1 is preferably, but not limited to, 10-100 μm; the thickness of the first electrolyte transition layer 4 is preferably, but not limited to, 5-50 μm; and / or, the thickness of the second electrolyte transition layer 5 is preferably, but not limited to, 5-50 μm.

[0074] like Figure 5 The method for preparing the electrolyte-supported single cell described above, provided by the present invention, includes the following steps:

[0075] Step S1: Based on the determined material composition of electrolyte layer 1, anode functional layer 2 and cathode functional layer 3, prepare slurries for electrolyte layer 1, anode functional layer 2 and cathode functional layer 3 respectively.

[0076] Step S2: According to the preset porosity of each first composite gradient support layer 41, the slurry of the anode functional layer 2 and the slurry of the electrolyte layer 1 are mixed in a certain proportion to obtain the slurry of the first electrolyte transition layer 4; and according to the preset porosity of each second composite gradient support layer 51, the slurry of the cathode functional layer 3 and the slurry of the electrolyte layer 1 are mixed in a certain proportion to obtain the slurry of the second electrolyte transition layer 5.

[0077] Step S3: Based on the preset thickness of electrolyte layer 1, prepare a wet electrolyte layer film by casting the slurry of electrolyte layer 1, and perform a first stripping sintering treatment on the wet electrolyte layer film to obtain electrolyte layer 1.

[0078] Step S4: The paste of the first electrolyte transition layer 4 is screen printed onto the front side of the electrolyte layer 1, and after the first drying process, the first electrolyte transition layer 4 is formed on the front side of the electrolyte layer 1.

[0079] Step S5: The paste of the anode functional layer 2 is screen-printed onto the surface of the first electrolyte transition layer 4. After the second drying treatment, the second stripping sintering treatment is performed to obtain a half cell.

[0080] Step S6: The paste of the second electrolyte transition layer 51 is screen printed onto the reverse side of the electrolyte layer 1 of the half cell, and after the third drying process, the second electrolyte transition layer 51 is formed on the reverse side of the electrolyte layer 1 of the half cell.

[0081] Step S7: The paste of the cathode functional layer 3 is screen-printed onto the surface of the second electrolyte transition layer 51. After the fourth drying process, the third stripping sintering process is performed to obtain an electrolyte-supported single cell.

[0082] In a preferred embodiment of the present invention, during the process of mixing the slurry of the anode functional layer 2 and the slurry of the electrolyte layer 1 in a certain proportion according to the preset porosity of each first composite gradient support layer 41 to obtain the slurry of the first electrolyte transition layer 4,

[0083] The slurry of the first electrolyte transition layer 4 includes the slurry of each first composite gradient support layer 41;

[0084] In the direction from electrolyte layer 1 to anode functional layer 2, the proportion of anode functional layer 2 slurry in the slurry of the first composite gradient support layer 41 gradually increases.

[0085] Specifically, since the first composite gradient support layer 41 has at least two layers, the slurry of the first composite gradient support layer 41 can be prepared according to the pre-set number of layers of the first composite gradient support layer 41 included in the first electrolyte transition layer 4. Because the porosity of the first composite gradient support layer 41 gradually increases in the direction from the electrolyte layer 1 to the anode functional layer 2, the proportion of the anode functional layer 2 slurry in the first composite gradient support layer 41 gradually increases in the direction from the electrolyte layer 1 to the anode functional layer 2. For example, the first electrolyte transition layer 4 includes five first composite gradient support layers 41. In the direction from electrolyte layer 1 to anode functional layer 2, the mass ratio of the slurry of the anode functional layer to the slurry of electrolyte layer 1 in the slurry of the first first composite gradient support layer 41 (i.e., the first composite gradient support layer 41 near the electrolyte layer), the slurry of the second first composite gradient support layer 41, the slurry of the third first composite gradient support layer 41, the slurry of the fourth first composite gradient support layer 41, and the slurry of the fifth first composite gradient support layer 41 (i.e., the first composite gradient support layer 41 near the anode functional layer) is 9:1, 7:3, 5:5, 3:7, and 1:9, respectively.

[0086] In a preferred embodiment of the present invention, during the process of mixing the slurry of the cathode functional layer 51 and the slurry of the electrolyte layer 1 in a certain proportion according to the preset porosity of each second composite gradient support layer 51 to obtain the slurry of the second electrolyte transition layer 5,

[0087] The slurry of the second electrolyte transition layer 5 includes the slurry of each second composite gradient support layer 51;

[0088] In the direction from the electrolyte layer 1 to the cathode functional layer 3, the proportion of the cathode functional layer 3 slurry in the slurry of the second composite gradient support layer 51 gradually increases.

[0089] Specifically, since the second composite gradient support layer 51 has at least two layers, the slurry of the second composite gradient support layer 51 can be prepared according to the pre-set number of layers of the second composite gradient support layer 51 included in the second electrolyte transition layer 5. Because the porosity of the second composite gradient support layer 51 gradually increases in the direction from the electrolyte layer 1 to the cathode functional layer 3, the proportion of the cathode functional layer 3 slurry in the second composite gradient support layer 51 gradually increases in the direction from the electrolyte layer 1 to the cathode functional layer 3. For example, the second electrolyte transition layer 5 includes five second composite gradient support layers 51. In the direction from electrolyte layer 1 to cathode functional layer 3, the mass ratio of the slurry of cathode functional layer 3 to the slurry of electrolyte layer 1 in the slurry of the first second composite gradient support layer 51 (i.e., the second composite gradient support layer 51 close to electrolyte layer 1), the slurry of the second second composite gradient support layer 51, the slurry of the third second composite gradient support layer 51, the slurry of the fourth second composite gradient support layer 51, and the slurry of the fifth second composite gradient support layer 51 (i.e., the second composite gradient support layer 51 close to cathode functional layer 3) is 9:1, 7:3, 5:5, 3:7, and 1:9, respectively.

[0090] As a preferred embodiment of the present invention, the temperature of the first debinding sintering treatment is 1450-1600℃; the debinding sintering time is 3-6h.

[0091] It should be noted that the preferred temperature for the first debinding sintering treatment is, but not limited to, 1450-1600℃; and the preferred sintering time is, but not limited to, 3-6 hours.

[0092] As a preferred embodiment of the present invention, during the process of screen printing the paste of the first electrolyte transition layer 41 onto the front side of the electrolyte layer 1 and performing a first drying treatment to form the first electrolyte transition layer 4 on the front side of the electrolyte layer 1,

[0093] The paste of the first electrolyte transition layer 4 is screen printed onto the front side of the electrolyte layer 1 in 3-5 steps;

[0094] The first drying process takes 5-25 minutes.

[0095] It should be noted that the number of times the paste for the first electrolyte transition layer 4 is screen-printed can be determined according to the actual situation, and the present invention does not impose any particular limitation on this. The preferred, but not limited, time for the first drying process is 5-25 minutes.

[0096] In a preferred embodiment of the present invention, after screen printing the paste of the anode functional layer 2 onto the surface of the first electrolyte transition layer 4, and performing a second debinding and sintering process to obtain the half-cell, the process involves...

[0097] The paste of the anode functional layer 2 is screen-printed onto the surface of the first electrolyte transition layer in 1-3 passes;

[0098] The second drying process takes 5-25 minutes;

[0099] The temperature for the second debinding sintering process is 1200-1350℃, and the debinding sintering time is 2-4 hours.

[0100] It should be noted that the number of times the paste for the anode functional layer 2 is screen printed can be determined according to the actual situation, and this invention does not impose any particular limitation on this. The second drying treatment time is preferably, but not limited to, 5-25 minutes; the temperature of the second debinding and sintering treatment is preferably, but not limited to, 1200-1350℃, and the debinding and sintering time is preferably, but not limited to, 2-4 hours.

[0101] In a preferred embodiment of the present invention, during the process of screen printing the paste of the second electrolyte transition layer 5 onto the reverse side of the electrolyte layer 1 of the half-cell and performing a third drying process to form the second electrolyte transition layer 5 on the reverse side of the electrolyte layer 1 of the half-cell,

[0102] The slurry of the second electrolyte transition layer is screen-printed onto the reverse side of the electrolyte layer of the half-cell in 3-5 passes.

[0103] The third drying process takes 5-25 minutes.

[0104] It should be noted that the number of screen printing cycles for the slurry in the second electrolyte transition layer can be determined according to actual conditions, and this invention does not impose any particular limitation on this. The preferred, but not limited, drying time is 5-25 minutes.

[0105] In a preferred embodiment of the present invention, after screen printing the paste of the cathode functional layer 3 onto the surface of the second electrolyte transition layer 5, and performing a fourth drying process, a third adhesive stripping and sintering process is carried out to obtain an electrolyte-supported single cell.

[0106] The paste of the cathode functional layer 3 is screen-printed onto the surface of the second electrolyte transition layer 5 in 1-3 passes;

[0107] The fourth drying process takes 5-25 minutes;

[0108] The temperature for the third debinding sintering process is 1100-1200℃, and the debinding sintering time is 2-4 hours.

[0109] It should be noted that the number of times the paste for the cathode functional layer 3 is screen printed can be determined according to the actual situation, and this invention does not impose any particular limitation on this. The drying time for the fourth process is preferably, but not limited to, 5-25 minutes; the temperature for the third debinding and sintering process is preferably, but not limited to, 1100-1200℃, and the debinding and sintering time is preferably, but not limited to, 2-4 hours.

[0110] To better illustrate the electrolyte-supported single cell and its preparation method provided by the present invention, the following specific embodiments are provided:

[0111] Example 1

[0112] Preparation of slurry for the anode functional layer: NiO powder, 8YSZ (yttrium octyl stabilized zirconium oxide) powder, pore-forming agent, binder, and plasticizer are added to an appropriate amount of solvent (the amount of solvent does not affect the technical effect of the present invention) in a mass ratio of 5:3:1:0.6:0.4, and ball-milled for 11 hours;

[0113] Cathode functional layer slurry preparation: LSM (lanthanum strontium manganese oxide) powder, pore-forming agent, binder, and plasticizer are added to an appropriate amount of solvent (the amount of solvent is determined according to the actual situation and does not affect the technical effect of the present invention) in a mass ratio of 10:3:1:0.6:0.4, and ball-milled for 11 hours;

[0114] Preparation of electrolyte layer slurry: 8YSZ powder, binder, plasticizer, and sintering aid are added to an appropriate amount of solvent (the amount of solvent does not affect the technical effect of the present invention) in a mass ratio of 10:1:0.8:0.2, and ball milled and dispersed for 11 hours;

[0115] Preparation of slurry for the first electrolyte transition layer: The slurry for the anode functional layer and the slurry for the electrolyte layer are prepared at a mass ratio of 9:1, 7:3, 5:5, 3:7, and 1:9, and then ball-milled and dispersed for 11 hours.

[0116] Preparation of slurry for the second electrolyte transition layer: The slurry of the cathode functional layer and the slurry of the electrolyte layer are prepared at a mass ratio of 9:1, 7:3, 5:5, 3:7, and 1:9, and then ball-milled and dispersed for 11 hours.

[0117] Preparation of electrolyte layer: The electrolyte layer slurry was cast and dried for 25 min to obtain a green body. The green body was then debonded and sintered at 1600℃ for 6 h to obtain an electrolyte layer with a thickness of 100 μm.

[0118] Preparation of half-cell: On the front side of the electrolyte layer, screen printing was performed 5 times in the order of the mass ratio of the slurry of the anode functional layer to the slurry of the electrolyte layer in the first electrolyte transition layer being 1:9, 3:7, 5:5, 7:3, and 9:1, respectively, and each time drying was performed for 5 minutes. The anode functional layer slurry was screen printed on the surface of the transition layer 1, screen printing was performed 3 times, drying was performed for 25 minutes, and the half-cell was sintered at 1350℃ for 4 hours to obtain the half-cell. The thickness of the transition layer 1 was 50 μm, and the thickness of the anode functional layer was 25 μm.

[0119] Preparation of a single cell: On the reverse side of the electrolyte layer, screen printing was performed 5 times in the order of the mass ratio of the cathode functional layer slurry to the electrolyte layer slurry in the second electrolyte transition layer being 1:9, 3:7, 5:5, 7:3, and 9:1, respectively, and drying was performed for 5 minutes each time. The cathode functional layer slurry was screen printed on the surface of the transition layer 2, screen printed 3 times, dried for 25 minutes, and then placed at 1200℃ for debinding and sintering for 4 hours to obtain a single cell with a thickness of 300 μm, wherein the thickness of the transition layer 2 is 50 μm and the thickness of the cathode functional layer is 75 μm.

[0120] The porosity of the prepared anode functional layer is 40%. In the direction from the anode functional layer to the cathode functional layer, the porosity of the first electrolyte transition layer decreases in a gradient of 30%, 20%, 10%, 5%, and 1%, while the porosity of the second electrolyte transition layer increases in a gradient of 1%, 5%, 10%, 20%, and 30%. The porosity of the electrolyte layer is 0.

[0121] The aforementioned pore-forming agent may be one of coal powder, carbon powder, ammonium carbonate, ammonium bicarbonate, ammonium chloride, polymethyl methacrylate, methyl methacrylate, starch, rice husk, and sawdust, or at least two of them mixed in any proportion.

[0122] The above-mentioned sintering aids are one of Al2O3, SiO2, cordierite, and mullite, or two of them mixed in any proportion.

[0123] The above-mentioned dispersant is one of triethanolamine, herring oil, trioleic acid glyceride, phosphate ester, or at least two of them mixed in any proportion.

[0124] The aforementioned adhesive is one of polyvinyl butyral, polymethyl methacrylate, epoxy resin, phenolic resin, ethyl cellulose, or at least two of them mixed in any proportion.

[0125] The plasticizer mentioned above is one of polyethylene glycol, phthalate, dibutyl phthalate, and diethyl phthalate, or at least two of them mixed in any proportion.

[0126] The organic solvent mentioned above is a binary azeotropic solvent system, which is any one of ethanol / butanone, ethanol / 3-methoxy-1-propanol, ethanol / trichloroethylene, ethanol / dimethylacetamide, and ethanol / terpineol.

[0127] All of the above raw materials can be purchased from the market.

[0128] It should be noted that the above specific embodiments are merely for illustrating the application of the electrolyte-supported single cell and its preparation method provided by the present invention in a practical process, and do not limit the technical solutions provided by the present invention.

[0129] As can be seen from the above specific embodiments, the electrolyte-supported single cell and its preparation method provided by the present invention, by setting a first electrolyte transition layer between the front side of the electrolyte layer and the anode functional layer; the first electrolyte transition layer includes at least two first composite gradient support layers; and the porosity of the first composite gradient support layers increases sequentially in the direction from the electrolyte layer to the anode functional layer, so as to form a gradient support structure between the electrolyte layer and the anode functional layer; by setting a second electrolyte transition layer between the back side of the electrolyte layer and the cathode functional layer; the second electrolyte transition layer includes at least two second composite gradient support layers; and the porosity of the second composite gradient support layers increases sequentially in the direction from the electrolyte layer to the cathode functional layer, so as to form a gradient support structure between the electrolyte layer and the cathode functional layer, thereby improving the interfacial contact between the anode functional layer, the electrolyte layer, and the cathode functional layer, optimizing the ion conduction path, reducing resistance, and maintaining high mechanical strength, thereby improving the reliability and long life of the electrolyte-supported SOFC single cell; and compared with the existing electrolyte-supported SOFC single cell, by reducing the interfacial resistance between the electrolyte layer and the cathode and anode functional layers, thereby reducing the internal resistance of the battery, the output performance can be improved.

[0130] The electrolyte-supported single cell and its preparation method according to the present invention have been described above by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that various modifications can be made to the electrolyte-supported single cell and its preparation method according to the present invention without departing from the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the contents of the appended claims.

Claims

1. An electrolyte-supported single cell, characterized in that, It includes an electrolyte layer, an anode functional layer and a cathode functional layer respectively disposed on the front and back sides of the electrolyte layer; wherein, A first electrolyte transition layer is disposed between the electrolyte layer and the anode functional layer; the first electrolyte transition layer is composed of the material of the anode functional layer and the material of the electrolyte layer, and the first electrolyte transition layer includes at least two first composite gradient support layers; in the direction from the electrolyte layer to the anode functional layer, the porosity of the first composite gradient support layers increases sequentially. A second electrolyte transition layer is provided between the electrolyte layer and the cathode functional layer; the second electrolyte transition layer is composed of the material of the cathode functional layer and the material of the electrolyte layer, and the second electrolyte transition layer includes at least two second composite gradient support layers; in the direction from the electrolyte layer to the cathode functional layer, the porosity of the second composite gradient support layers increases sequentially.

2. The electrolyte-supported single cell according to claim 1, characterized in that, The material of the anode functional layer is NiO-Zr. 1-x Y x O 2-δ NiO-Zr 1-x Sc x O 2-δ NiO-Ce 1-x Gd x O2-δ, NiO-Ce 1-x Sm x Any one of O2-δ or at least two mixed in any proportion.

3. The electrolyte-supported single cell according to claim 1, characterized in that, The material of the cathode functional layer is La. 1-x Sr x MnO 3-δ La 1-x Sr x Co 1-y Fe y O 3-δ 、Sm 0.5 Sr 0.5 CoO 3-δ Ba 0.5 Sr 0.5 Co 0.5 Fe 0.2 O 3-δ Any one of them or at least two mixed in any proportion.

4. The electrolyte-supported single cell according to claim 1, characterized in that, The electrolyte layer is made of Zr. 1-x Y x O 2-δ Zr 1-x Sc x O 2-δ Ce 1-x Gd x O 2-δ Ce 1-x Sm x Any one of O2-δ or at least two mixed in any proportion.

5. The electrolyte-supported single cell according to claim 1, characterized in that, The porosity of the anode functional layer is 20-40%; The porosity of the cathode functional layer is 20-40%; The porosity of the electrolyte layer is 0; The porosity of the first composite gradient support layer is 1-30%; The porosity of the second composite gradient support layer is 1-30%.

6. The electrolyte-supported single cell according to claim 1, characterized in that, The thickness of the anode functional layer is 5-25 μm.

7. The electrolyte-supported single cell according to claim 1, characterized in that, The thickness of the cathode functional layer is 5-75 μm.

8. The electrolyte-supported single cell according to claim 1, characterized in that, The thickness of the electrolyte layer is 10-100 μm; and / or, The thickness of the first electrolyte transition layer is 5-50 μm; and / or, The thickness of the second electrolyte transition layer is 5-50 μm.

9. A method for preparing an electrolyte-supported single cell as described in any one of claims 1-8, characterized in that, Includes the following steps: Based on the determined material composition of the electrolyte layer, the anode functional layer, and the cathode functional layer, slurries for the electrolyte layer, the anode functional layer, and the cathode functional layer are prepared accordingly. According to the preset porosity of each first composite gradient support layer, the slurry of the anode functional layer and the slurry of the electrolyte layer are mixed in a certain proportion to obtain the slurry of the first electrolyte transition layer; and according to the preset porosity of each second composite gradient support layer, the slurry of the cathode functional layer and the slurry of the electrolyte layer are mixed in a certain proportion to obtain the slurry of the second electrolyte transition layer. According to the preset thickness of the electrolyte layer, a wet film of the electrolyte layer is prepared by casting the slurry of the electrolyte layer, and the wet film of the electrolyte layer is subjected to a first row of adhesive sintering treatment to obtain the electrolyte layer; The paste of the first electrolyte transition layer is screen-printed onto the front side of the electrolyte layer, and after a first drying process, the first electrolyte transition layer is formed on the front side of the electrolyte layer. The paste of the anode functional layer is screen-printed onto the surface of the first electrolyte transition layer. After a second drying process, a second stripping sintering process is performed to obtain a half cell. The paste of the second electrolyte transition layer is screen-printed onto the reverse side of the electrolyte layer of the half cell, and after a third drying process, the second electrolyte transition layer is formed on the reverse side of the electrolyte layer of the half cell. The paste of the cathode functional layer is screen-printed onto the surface of the second electrolyte transition layer. After a fourth drying process, a third stripping sintering process is performed to obtain an electrolyte-supported single cell.

10. The method for preparing an electrolyte-supported single cell according to claim 9, characterized in that, In the process of mixing the slurry of the anode functional layer and the slurry of the electrolyte layer in a certain proportion according to the preset porosity of each first composite gradient support layer to obtain the slurry of the first electrolyte transition layer, The slurry of the first electrolyte transition layer includes the slurry of each first composite gradient support layer; In the direction from the electrolyte layer to the anode functional layer, the proportion of the anode functional layer slurry in the slurry of the first composite gradient support layer gradually increases.

11. The method for preparing an electrolyte-supported single cell according to claim 9, characterized in that, In the process of mixing the slurry of the cathode functional layer and the slurry of the electrolyte layer in a certain proportion according to the preset porosity of each second composite gradient support layer to obtain the slurry of the second electrolyte transition layer, The slurry of the second electrolyte transition layer includes the slurry of each second composite gradient support layer; In the direction from the electrolyte layer to the cathode functional layer, the proportion of the cathode functional layer slurry in the slurry of the second composite gradient support layer gradually increases.

12. The method for preparing an electrolyte-supported single cell according to claim 9, characterized in that, The temperature of the first debinding sintering treatment is 1450-1600℃; the debinding sintering time is 3-6h.

13. The method for preparing an electrolyte-supported single cell according to claim 9, characterized in that, During the process of screen printing the paste of the first electrolyte transition layer onto the front side of the electrolyte layer and performing a first drying treatment to form the first electrolyte transition layer on the front side of the electrolyte layer. The paste of the first electrolyte transition layer is screen-printed onto the front side of the electrolyte layer in 3-5 passes; The first drying process takes 5-25 minutes.

14. The method for preparing an electrolyte-supported single cell according to claim 9, characterized in that, In the process of screen printing the paste of the anode functional layer onto the surface of the first electrolyte transition layer, followed by a second drying process and a second adhesive stripping and sintering process to obtain the half-cell, The paste of the anode functional layer is screen-printed onto the surface of the first electrolyte transition layer in 1-3 passes; The second drying process takes 5-25 minutes; The temperature of the second debinding sintering treatment is 1200-1350℃, and the debinding sintering time is 2-4h.

15. The method for preparing an electrolyte-supported single cell according to claim 9, characterized in that, During the process of screen printing the paste for the second electrolyte transition layer onto the reverse side of the electrolyte layer of the half-cell, followed by a third drying process, the second electrolyte transition layer is formed on the reverse side of the electrolyte layer of the half-cell. The slurry of the second electrolyte transition layer is screen-printed onto the reverse side of the electrolyte layer of the half-cell in 3-5 passes. The third drying process takes 5-25 minutes.

16. The method for preparing an electrolyte-supported single cell according to claim 9, characterized in that, In the process of screen printing the paste of the cathode functional layer onto the surface of the second electrolyte transition layer, followed by a fourth drying process and a third sintering process to obtain an electrolyte-supported single cell, the following steps are performed: The paste of the cathode functional layer is screen-printed onto the surface of the second electrolyte transition layer in 1-3 passes; The fourth drying process takes 5-25 minutes; The temperature for the third debinding sintering process is 1100-1200℃, and the debinding sintering time is 2-4 hours.

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