An electrode support layer, a method of manufacturing the same, and a battery

Abstract

The application discloses an electrode support layer, a preparation method thereof and a battery. The electrode support layer comprises a first ceramic layer and a second ceramic layer which are stacked. The first ceramic layer comprises the following raw materials by mass percentage: ceramic powder 45-60%, a first binder 7-12%, a dispersing agent 0.1-0.5%, and a solvent 27.5-47.5%. The first binder contains polyvinyl alcohol and polyacrylic acid in a mass ratio of (1.5-4):1. The second ceramic layer comprises the following raw materials by mass percentage: ceramic powder 45-60%, a second binder 7-12%, a dispersing agent 0.1-0.5%, and a solvent 27.5-47.5%. The second binder contains polyvinyl alcohol and polyacrylic acid in a mass ratio of (0.75-1):1. The electrode support layer has high porosity, a high ratio of straight-through holes and high bending strength.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide fuel cell / electrolyte technology, specifically relating to an electrode support layer, its preparation method, and a battery. Background Technology

[0002] Solid oxide fuel cells / electrolytes (SOFCs / SOECs), as high-efficiency energy conversion devices, require a high porosity to ensure fuel gas transmission. The porous structure of the hydrogen electrode support layer directly affects the gas diffusion efficiency and long-term operational stability of the battery, and also requires high mechanical strength to ensure that the battery cells or electrolyzer cells are not damaged by mechanical vibration during assembly and long-term operation. Traditional hydrogen electrode support layers generally adopt a process of mixing solid pore-forming agents (such as graphite and starch) with ceramic powder (NiO-YSZ) and then sintering at high temperature. It is not easy to prepare an electrode support layer structure with good porosity and structural strength. When applied in SOFCs, carbon buildup is prone to occur on the anode during long-term operation, leading to changes in porosity, increased battery polarization resistance, increased fuel utilization, and reduced battery life. These problems limit the use of electrode support layers. Summary of the Invention

[0003] In order to overcome at least one of the technical problems existing in the prior art, one of the objectives of the present invention is to provide an electrode support layer.

[0004] The second objective of this invention is to provide a method for preparing an electrode support layer.

[0005] The third objective of this invention is to provide a battery.

[0006] The fourth objective of this invention is to provide a method for preparing a battery.

[0007] The fifth objective of this invention is to provide a battery or electrolytic cell.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A first aspect of the present invention provides an electrode support layer comprising a first ceramic layer and a second ceramic layer stacked thereon; the first ceramic layer comprises the following raw materials by mass percentage: 45-60% ceramic powder, 7-12% first binder, 0.1-0.5% dispersant, and 27.5-47.5% solvent; The first adhesive contains polyvinyl alcohol and polyacrylic acid, wherein the mass ratio of polyvinyl alcohol to polyacrylic acid is (1.5~4):1; The second ceramic layer comprises the following raw materials by mass percentage: 45-60% ceramic powder, 7-12% second binder, 0.1-0.5% dispersant, and 27.5-47.5% solvent; The second adhesive contains polyvinyl alcohol and polyacrylic acid, wherein the mass ratio of polyvinyl alcohol to polyacrylic acid is (0.75~1):1.

[0009] In this invention, the ratios of polyvinyl alcohol (PVA) and polyacrylic acid (PAA) in the first and second binders are different. By adjusting the content of PVA and PAA in the first and second ceramic layers, the content of PVA in the first ceramic layer is greater than that in the second ceramic layer. During the phase replacement process in the preparation of the electrode support layer, the phase separation rate and phase transformation rate of the first ceramic layer are accelerated, thereby forming through-holes. Furthermore, PVA can form a hydrogen bond network with the ceramic powder surface, improving the stability of the ceramic slurry, while PAA enables the electrode support layer to have higher mechanical strength. Compared to other combinations, the combination of PVA and PAA has better compatibility, resulting in an electrode support layer with excellent overall performance.

[0010] In some embodiments of the present invention, the mass percentage of ceramic powder in the first ceramic slurry is any one of 45%, 46%, 48%, 50%, 52%, 54%, 55%, 56%, 58%, 60%, or a range formed by any two of these values.

[0011] In some embodiments of the present invention, the mass percentage of the first binder in the first ceramic slurry is any value of 7%, 8%, 9%, 10%, 11%, 12%, or a range formed by any two of these values.

[0012] In some embodiments of the present invention, the mass percentage of the dispersant in the first ceramic slurry is any one of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or a range formed by any two of these values.

[0013] In some embodiments of the present invention, the mass percentage of solvent in the first ceramic slurry is any one of 27.5%, 28%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, 42%, 44%, 45%, 46%, 47.5%, or a range formed by any two of these values.

[0014] In some embodiments of the present invention, the mass ratio of polyvinyl alcohol (PVA) to polyacrylic acid (PAA) in the first binder is any one of 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, or 4:1, or any range formed by both. If the mass ratio of PVA to PAA is greater than 4:1, the excess PVA leads to strong thixotropy in the slurry, making it prone to defects such as bubbles and marks during subsequent coating processes, and also reducing the proportion of through holes in the resulting electrode support layer. If the mass ratio of PVA to PAA is less than 1.5:1, it affects the coating quality of the slurry, causing microcracks in the product after sintering and a significant decrease in product strength.

[0015] In some embodiments of the present invention, the mass percentage of ceramic powder in the second ceramic slurry is any one of 45%, 46%, 48%, 50%, 52%, 54%, 55%, 56%, 58%, 60%, or a range formed by any two of these values.

[0016] In some embodiments of the present invention, the mass percentage of the second binder in the second ceramic slurry is any one of 7%, 8%, 9%, 10%, 11%, 12%, or a range formed by any two of these values.

[0017] In some embodiments of the present invention, the mass percentage of the dispersant in the second ceramic slurry is any one of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or a range formed by any two of these values.

[0018] In some embodiments of the present invention, the mass percentage of the solvent in the second ceramic slurry is any one of 27.5%, 28%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, 42%, 44%, 45%, 46%, 47.5%, or a range formed by any two of these values.

[0019] In some embodiments of the present invention, the mass ratio of polyvinyl alcohol (PVA) to polyacrylic acid (PAA) in the second adhesive is any one of 0.75:1, 0.78:1, 0.8:1, 0.82:1, 0.84:1, 0.85:1, 0.86:1, 0.88:1, 0.9:1, 0.92:1, 0.94:1, 0.95:1, 0.96:1, 0.97:1, 0.98:1, 0.99:1, or 0.999:1, or a range formed by any two of these values. The amount of polyvinyl alcohol in the second adhesive is less than the amount of polyacrylic acid.

[0020] In some embodiments of the present invention, the ceramic powder comprises NiO and yttrium-stabilized zirconium oxide in a mass ratio of 1:(0.4~1); in some embodiments of the present invention, the mass ratio of NiO and yttrium-stabilized zirconium oxide is any value of 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0 or a range formed by any two of these values.

[0021] In some embodiments of the present invention, the yttrium-stabilized zirconium oxide is composed of 5-10% by mass of yttrium oxide and 90-95% by mass of zirconium oxide; in some embodiments of the present invention, the yttrium-stabilized zirconium oxide is composed of 8% by mass of yttrium oxide and 92% by mass of zirconium oxide.

[0022] In some embodiments of the present invention, the average particle size of the yttrium-stabilized zirconium oxide (YSZ) is 0.3~0.8 μm; in some embodiments of the present invention, the average particle size of the yttrium-stabilized zirconium oxide is 0.5 μm.

[0023] In some embodiments of the present invention, the dispersant includes at least one of ammonium polyacrylate, ammonium polycarboxylate, and polyethylene glycol.

[0024] In some embodiments of the present invention, the solvent includes water.

[0025] In some embodiments of the present invention, the thickness ratio of the first ceramic layer and the second ceramic layer is (3~10):1; in some embodiments of the present invention, the thickness ratio of the first ceramic layer and the second ceramic layer is any value of 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1 or any range formed by both.

[0026] In some embodiments of the present invention, the porosity of the electrode support layer is ≥32%; in some embodiments of the present invention, the porosity of the electrode support layer is 32~44%.

[0027] In some embodiments of the present invention, the number of through holes in the electrode support layer accounts for more than 83% of the total number of holes; in some embodiments of the present invention, the number of through holes in the electrode support layer accounts for 83-92% of the total number of holes.

[0028] In some embodiments of the present invention, the bending strength of the electrode support layer is ≥294MPa; in some embodiments of the present invention, the bending strength of the electrode support layer is 294~400MPa.

[0029] A second aspect of the present invention provides a method for preparing the electrode support layer described in the first aspect of the present invention, comprising the following steps: The raw materials for preparing the first ceramic layer and the second ceramic layer are mixed separately to obtain the first ceramic slurry and the second ceramic slurry. The electrode support layer is obtained by sequentially coating a first ceramic slurry and a second ceramic slurry onto a substrate and then immersing it in a displacement solution for displacement treatment. The replacement solution contains ethanol and ethyl acetate in a volume ratio of (2~5):1.

[0030] In the preparation of the electrode support layer, phase displacement can be performed by a first binder and a second binder in a displacement solution including ethanol and ethyl acetate, thereby changing the composition or structure of the material. This invention utilizes the principle of phase displacement to adjust the shape and size of the formed through-holes, thereby obtaining a first ceramic layer and a second ceramic layer with different pore structures.

[0031] The first ceramic layer of the present invention has a high PVA content, and the PVA molecular chains preferentially precipitate in the displacement solution and form a through-pore framework through hydrogen bonding; the second ceramic layer has a low PVA content, and PAA dissolves rapidly in ethyl acetate, inhibiting the formation of surface closed pores and forming a dense gas diffusion barrier.

[0032] In some embodiments of the present invention, the preparation method further includes a step of drying after removal; the step of drying after removal is located after the displacement treatment step.

[0033] In some embodiments of the present invention, the drying step specifically involves: first, maintaining the temperature at 40-60°C for 10-13 hours while controlling the humidity at 40-60%; then, vacuum drying at 70-90°C for 5-8 hours. The replaced membrane strip is then kept at this temperature to form a 3D gel network of PVA, followed by further drying to obtain the desired electrode support layer.

[0034] In some embodiments of the present invention, the coating thickness of the first ceramic slurry is 200~400μm; in some embodiments of the present invention, the coating thickness of the first ceramic slurry is any value or a range formed by any two of the following: 200μm, 220μm, 240μm, 250μm, 260μm, 280μm, 300μm, 320μm, 340μm, 350μm, 360μm, 380μm, 400μm.

[0035] In some embodiments of the present invention, the coating thickness of the second ceramic slurry is 40~60μm; in some embodiments of the present invention, the coating thickness of the second ceramic slurry is any value or a range formed by any two of 40μm, 42μm, 44μm, 45μm, 46μm, 48μm, 50μm, 52μm, 54μm, 55μm, 56μm, 58μm, and 60μm.

[0036] In some embodiments of the present invention, the volume ratio of ethanol to ethyl acetate is any value or a range formed by any two of the following: 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, and 5:1. If the volume ratio of ethanol to ethyl acetate is less than 2:1, the solubility of ethyl acetate is insufficient, the phase separation rate is too slow, resulting in tortuous pores in the first ceramic layer and a reduced proportion of straight pores; if the volume ratio of ethanol to ethyl acetate is greater than 5:1, the phase separation is too fast, the pore wall roughness Ra > 0.8 μm, and the flexural strength decreases to < 300 MPa.

[0037] In some embodiments of the present invention, the temperature of the replacement fluid is 20~30°C; in some embodiments of the present invention, the temperature of the replacement fluid is any value of 20°C, 22°C, 24°C, 25°C, 26°C, 28°C, 30°C, or a range formed by any two of these values.

[0038] In some embodiments of the present invention, the displacement treatment time is 10 to 30 minutes; in some embodiments of the present invention, the displacement treatment time is any value or a range formed by any two of 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, 22 minutes, 24 minutes, 26 minutes, 28 minutes, and 30 minutes.

[0039] A third aspect of the present invention provides a battery including the electrode support layer described in the first aspect of the present invention.

[0040] In some embodiments of the present invention, the battery further includes an anode functional layer and an electrolyte layer sequentially stacked on the electrode support layer.

[0041] In some embodiments of the present invention, a catalyst is loaded in the electrode support layer.

[0042] In some embodiments of the present invention, the catalyst contains Ni and CeO2.

[0043] A fourth aspect of the present invention provides a method for preparing a battery, comprising the following steps: A semi-finished half-cell is obtained by screen printing an anode functional layer and an electrolyte layer on the electrode support layer described in the first aspect of the present invention and calcining it. The half-cell semi-finished product is immersed in an impregnation solution containing a catalyst precursor, then centrifuged, and then sintered. The sintering process involves a first sintering at 350-550°C, followed by a second sintering at 600-800°C.

[0044] In some embodiments of the present invention, the calcination temperature is 1150~1450℃; in some embodiments of the present invention, the calcination temperature is any value of 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃ or a range formed by any two of them.

[0045] In some embodiments of the present invention, the calcination time is 2 to 5 hours.

[0046] In some embodiments of the present invention, the heating rate of the calcination is 0.5~2℃ / min.

[0047] In some embodiments of the present invention, the temperature of the first sintering is any value or a range formed by any two of the following: 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, and 550°C.

[0048] In some embodiments of the present invention, the first sintering is performed in an air atmosphere.

[0049] In some embodiments of the present invention, the first sintering time is 0.5 to 2 hours; in some embodiments of the present invention, the first sintering time is any value of 0.5 hours, 1 hour, 1.5 hours, 2 hours, or a range formed by any two of them.

[0050] In some embodiments of the present invention, the temperature of the second sintering is any value or a range formed by any two of 600°C, 620°C, 640°C, 650°C, 660°C, 680°C, 700°C, 720°C, 740°C, 750°C, 760°C, 780°C, and 800°C.

[0051] In some embodiments of the present invention, the second sintering time is 1 to 3 hours; in some embodiments of the present invention, the second sintering time is any value or a range formed by any two of the following: 1 hour, 1.2 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.8 hours, and 3 hours.

[0052] In some embodiments of the present invention, the second sintering is performed under a reducing atmosphere.

[0053] In some embodiments of the present invention, the reducing atmosphere is a mixture of hydrogen and nitrogen in a volume ratio of 1:(8~10).

[0054] If the temperature of the first sintering is below 350℃, the residual organic matter will not be fully decomposed, leading to coking and affecting the sintering behavior of the supported catalyst. If the temperature is above 550℃, the decomposition rate of the catalyst precursor will be accelerated, and the catalyst growth will be uncontrolled. Therefore, controlling the temperature of the first sintering at 350~550℃ can effectively remove residual organic matter without affecting the sintering of the catalyst.

[0055] If the second sintering temperature is below 600℃, the supported catalyst will agglomerate during reduction, leading to loss of active surface area and decreased performance. If the second sintering temperature is above 800℃, the highly active nanocatalyst will continue to undergo sintering and growth, resulting in performance degradation. Therefore, controlling the second sintering temperature between 600 and 800℃ can effectively control the nucleation rate and prevent particle agglomeration, thereby obtaining a catalyst of ideal size and effectively expanding the three-phase reaction interface.

[0056] This invention controls the nucleation rate of the Ni-CeO2 catalyst through a two-stage calcination process, avoiding the oxygen vacancy effect of CeO2 particle agglomeration and improving ionic conductivity. The nano-sized catalyst obtained by reduction can expand the three-phase reaction interface, compensating for the insufficient reaction sites caused by the through-pore structure.

[0057] In some embodiments of the present invention, the pressure of the step of immersing the half-cell semi-finished product in the impregnation solution containing the catalyst precursor is -0.03 to -0.08 MPa. Impregnation under this pressure can allow the catalyst precursor to fully enter the pores of the electrode support layer.

[0058] In some embodiments of the present invention, the temperature of the impregnation solution is 25~35°C.

[0059] In some embodiments of the present invention, the immersion time of the half-cell semi-finished product in the impregnation solution containing the catalyst precursor is 20-40 minutes.

[0060] In some embodiments of the present invention, the step of immersing the half-cell semi-finished product in an impregnation solution containing a catalyst precursor specifically involves immersing the half-cell semi-finished product in the impregnation solution containing the catalyst precursor for 20-40 minutes at a pressure of -0.03 to -0.08 MPa and a temperature of 25 to 35°C. The present invention employs an ion impregnation method, allowing the impregnation solution to enter the half-cell semi-finished product, and after sintering, a layer of catalyst is loaded onto the inner wall of the through-hole.

[0061] In some embodiments of the present invention, the impregnation solution contains nickel nitrate, cerium nitrate and polyvinylpyrrolidone (PVP); nickel nitrate and cerium nitrate serve as catalyst precursors.

[0062] In some embodiments of the present invention, the impregnation solution also contains a solvent.

[0063] In some embodiments of the present invention, the solvent in the impregnation solution is water.

[0064] In some embodiments of the present invention, the molar ratio of nickel nitrate to cerium nitrate is (2~4):1.

[0065] In some embodiments of the present invention, the total molar concentration of nickel nitrate and cerium nitrate in the impregnation solution is 0.5~2 mol / L.

[0066] In some embodiments of the present invention, the mass of the polyvinylpyrrolidone is 0.1 to 0.3% of the total mass of the impregnation solution.

[0067] In some embodiments of the present invention, the centrifugation speed is 800~1000 rpm.

[0068] In some embodiments of the present invention, the centrifugation time is 1 to 3 minutes.

[0069] A fifth aspect of the present invention provides a battery or electrolytic cell comprising the electrode support layer described in the first aspect of the present invention or the battery described in the third aspect of the present invention.

[0070] In some embodiments of the present invention, the battery includes a solid oxide fuel cell.

[0071] In some embodiments of the present invention, the electrolytic cell includes a solid oxide fuel electrolytic cell.

[0072] The beneficial effects of the present invention are: the electrode support layer of the present invention has a high porosity (≥32%), a high proportion of through holes (≥83%) and a high bending strength (≥294MPa). When applied to solid oxide fuel cells or solid oxide fuel electrolyzers, it can significantly improve gas diffusion performance and reduce polarization resistance and carbon deposition.

[0073] The electrode support layer preparation method of the present invention forms a through-hole structure in the electrode support layer through a gradient phase separation process. By adjusting the formulation of the first binder and the second binder, the first ceramic layer has a high polyvinyl alcohol content. During the phase replacement process, the phase separation rate and phase transformation rate of the first ceramic layer are accelerated, thereby forming through-holes. This achieves the control of the porosity and pore shape in the electrode support layer, and improves the performance and operational stability of the battery containing the electrode support layer.

[0074] The battery in this invention uses an electrode support layer with a through-hole ratio of not less than 83%, thereby achieving a polarization impedance of ≤0.13Ω·cm², a carbon deposition of ≤0.2wt% over 1200h, and a superior overall performance, making it suitable for large-scale production. Detailed Implementation

[0075] The following examples provide a more detailed description of the specific implementation of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are methods that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0076] YSZ is yttrium oxide-stabilized zirconium oxide with a particle size of 0.5 μm. It consists of 8% yttrium oxide and 92% zirconium oxide.

[0077] Example 1 This example provides a method for preparing an electrode support layer, including the following steps: S1. NiO and YSZ are mixed at a mass ratio of 6:4 to obtain ceramic powder. Then, 55% of the ceramic powder, 10% of the first binder, and 0.3% of the dispersant (i.e., ammonium polyacrylate) are weighed out, with deionized water as the remainder. All raw materials are mixed and dispersed to obtain the first ceramic slurry (as the bottom ceramic slurry). The first binder is PVA and PAA at a mass ratio of 2:1. S2. NiO and YSZ are mixed at a mass ratio of 6:4 to obtain ceramic powder. Then, 55% of the ceramic powder, 10% of the second binder, and 0.3% of the dispersant (i.e., ammonium polyacrylate) are weighed out, with deionized water as the remainder. All raw materials are mixed and dispersed to obtain the second ceramic slurry (as the surface ceramic slurry). The mass ratio of PVA to PAA in the second binder is 1:1. S3. Coat the baseband with the first ceramic slurry, with a thickness controlled at 200μm, to obtain the first ceramic layer; S4. Coat the first ceramic layer with the second ceramic slurry, with a thickness controlled at 40 μm, to obtain the second ceramic layer; after coating, immerse the membrane strip in the replacement solution for phase separation, with the temperature controlled at 20℃ and the treatment time at 10 min; the replacement solution is composed of ethanol and ethyl acetate, with a volume ratio of ethanol to ethyl acetate of 7:3; S5. Then dry at 40℃ for 10 hours, and then heat to 70℃ and vacuum dry for 5 hours to obtain the electrode support layer in this example.

[0078] This example also provides a half-cell semi-finished product, which is obtained by screen printing an electrode functional layer (material YSZ+NiO, layer thickness 10μm) and an electrolyte layer (material YSZ, layer thickness 25μm) on the electrode support layer prepared in this example, and sintering it at 1300℃ for 2.5h.

[0079] Examples 2-3 The only difference between the preparation method of the electrode support layer in Examples 2 and 3 and that in Example 1 is that the mass ratio of PVA to PAA in the first binder is different, as shown in Table 1 below.

[0080] Examples 4-5 The only difference between the preparation method of the electrode support layer in Examples 4 and 5 and that in Example 1 is that the mass percentage of ceramic powder in the first ceramic slurry is different, as shown in Table 1 below.

[0081] Examples 6-7 The only difference between the preparation method of the electrode support layer in Examples 6 and 7 and that in Example 1 is that the mass percentage of the first binder in the first ceramic slurry is different, as shown in Table 1 below.

[0082] Examples 8-9 The only difference between the preparation method of the electrode support layer in Examples 8 and 9 and that in Example 1 is that the mass percentage of the dispersant in the first ceramic slurry is different, as shown in Table 1 below.

[0083] Examples 10-11 The only difference between the preparation method of the electrode support layer in Examples 10-11 and Example 1 is that the mass ratio of PVA to PAA in the second binder is different, as shown in Table 1 below.

[0084] Examples 12-13 The only difference between the preparation method of the electrode support layer in Examples 12 and 13 and that in Example 1 is that the mass percentage of ceramic powder in the second ceramic slurry is different, as shown in Table 1 below.

[0085] Examples 14-15 The only difference between the preparation method of the electrode support layer in Examples 14 and 15 and that in Example 1 is that the mass percentage of the second binder in the second ceramic slurry is different, as shown in Table 1 below.

[0086] Examples 16-17 The only difference between the preparation method of the electrode support layer in Examples 16 and 17 and that in Example 1 is that the mass percentage of the dispersant in the second ceramic slurry is different, as shown in Table 1 below.

[0087] Examples 18-19 The only difference between the preparation method of the electrode support layer in Examples 18-19 and Example 1 is that the mass ratio of ethanol to ethyl acetate in the replacement solution is different in step S4, as shown in Table 1 below.

[0088] Comparative Example 1 This example provides a method for preparing an electrode support layer, which uses only a first ceramic slurry and specifically includes the following steps: S1. NiO and YSZ are mixed at a mass ratio of 6:4 to obtain ceramic powder. Then, 55% of the ceramic powder, 10% of the first binder, and 0.3% of the dispersant (i.e., ammonium polyacrylate) are weighed out, with deionized water as the remainder. All raw materials are mixed and dispersed to obtain the first ceramic slurry (as the bottom ceramic slurry). The first binder is PVA and PAA at a mass ratio of 2:1. S2. Coat the baseband with the first ceramic slurry, with a thickness controlled at 240 μm, to obtain the first ceramic layer; S3. After coating, immerse the membrane strip in the replacement solution for phase separation. The temperature is controlled at 20℃ and the treatment time is 10 min. The replacement solution is composed of ethanol and ethyl acetate, with a volume ratio of 7:3. S4. Then dry at 40°C for 10 hours, and then heat to 70°C and vacuum dry for 5 hours to obtain the electrode support layer in this example.

[0089] Comparative Examples 2-3 The only difference between the preparation method of the electrode support layer in Comparative Examples 2 and 3 and Example 1 is that the mass ratio of PVA to PAA in the first binder is different, as shown in Table 1 below.

[0090] Comparative Examples 4-5 The only difference between the preparation method of the electrode support layer in Comparative Examples 4 and 5 and Example 1 is that the mass percentage of ceramic powder in the first ceramic slurry is different, as shown in Table 1 below.

[0091] Comparative Examples 6-7 The only difference between the preparation method of the electrode support layer in Comparative Examples 6 and 7 and Example 1 is that the mass percentage of the first binder in the first ceramic slurry is different, as shown in Table 1 below.

[0092] Comparative Examples 8-9 The only difference between the preparation method of the electrode support layer in Comparative Examples 8 and 9 and Example 1 is that the mass percentage of the dispersant in the first ceramic slurry is different, as shown in Table 1 below.

[0093] Comparative Examples 10-11 The only difference between the preparation method of the electrode support layer in Comparative Examples 10-11 and Example 1 is that the mass ratio of PVA to PAA in the second ceramic slurry and the second binder is different, as shown in Table 1 below.

[0094] Comparative Examples 12-13 The only difference between the preparation method of the electrode support layer in Comparative Examples 12-13 and Example 1 is that the mass percentage of ceramic powder in the second ceramic slurry is different, as shown in Table 1 below.

[0095] Comparative Examples 14-15 The only difference between the preparation method of the electrode support layer in Comparative Examples 14-15 and Example 1 is that the mass percentage of the second binder in the second ceramic slurry is different, as shown in Table 1 below.

[0096] Comparative Examples 16-17 The only difference between the preparation method of the electrode support layer in Comparative Examples 16-17 and Example 1 is that the mass percentage of the dispersant in the second ceramic slurry is different, as shown in Table 1 below.

[0097] Comparative Examples 18-19 The only difference between the preparation method of the electrode support layer in Comparative Examples 18-19 and Example 1 is that the mass ratio of ethanol to ethyl acetate in the replacement solution is different in step S4, as shown in Table 1 below.

[0098] Table 1. Fabrication parameters of the electrode support layer in Examples 1-19 and Comparative Examples 1-19

[0099] The porosity, through-hole ratio, and flexural strength of the electrode support layers prepared in Examples 1-19 and Comparative Examples 1-19 were tested respectively. The specific test methods are as follows: Porosity and through-hole ratio: 3D reconstruction using micro-CT was used to determine the through-hole ratio and porosity. The through-hole ratio is calculated as the number of through-holes / the total number of pores * 100%, with a through-hole ratio ≥ 85% and a porosity ≥ 35%. Bending strength: The strength was tested using an SKCS universal material tester according to the three-point bending method. The bending strength was required to be ≥300MPa. The performance data of the electrode support layers prepared in Examples 1-19 and Comparative Examples 1-19, obtained according to the above test methods, are shown in Table 2 below.

[0100] Table 2 Performance test results of the electrode support layer

[0101] As shown in Table 2, this invention achieves a porosity ≥35%, a through-hole ratio ≥85%, and a flexural strength ≥300 MPa by controlling parameters such as the mass ratio of PVA and PAA in the first and second binders and the displacement liquid ratio. Specifically, the electrode support layer prepared by the methods in Examples 1-19 of this invention has a porosity of 35-44%, a through-hole ratio of 85-92%, and a flexural strength of 300-394 MPa. In Comparative Example 5, the ceramic powder content was too high, making it impossible to form a usable first ceramic slurry. In Comparative Example 13, the ceramic powder content was too high, making it impossible to obtain a usable second ceramic slurry. Therefore, the material ratios in Comparative Examples 5 and 13 cannot be used to prepare the electrode support layer. Furthermore, Comparative Examples 1-19 adjusted the formulations of the first and second ceramic slurries and the displacement liquid, thus preventing the formation of a pore structure with a through-hole ratio of not less than 80% in the electrode support layer, thereby failing to meet the requirements for use in solid oxide fuel cells or solid oxide fuel electrolyzers.

[0102] The electrode support layers in Examples 2-19 and Comparative Examples 1-19 were prepared into half-cell semi-finished products according to the preparation method of the half-cell semi-finished product in Example 1.

[0103] Example 20 This example provides a method for preparing a half-cell, including the following steps: (1) The half-cell semi-finished product prepared from the electrode support layer in Example 1 was immersed in the impregnation solution and vacuum impregnated for 20 min at 0.03 MPa and 25 °C, and then centrifuged at 1000 rpm for 1 min to remove excess solution; the impregnation solution contained nickel nitrate, cerium nitrate, and polyvinylpyrrolidone (PVP), the molar ratio of nickel nitrate to cerium nitrate was 2:1, and it was prepared as an aqueous solution with a total molar concentration of nickel nitrate and cerium nitrate of 0.5 mol / L, and the mass percentage of PVP in the impregnation solution was 0.1% (based on the total mass of the impregnation solution); After impregnation, the half-cell is sintered for 1 hour at 400°C (the first sintering temperature) in an air atmosphere, and then heated to 650°C (the second sintering temperature) for 2 hours in a reducing atmosphere (volume ratio: H2:N2=1:9) to obtain the half-cell.

[0104] Example 21 The only difference between the preparation method of the half-cell in this example and that in Example 20 is that the half-cell semi-finished product is made from the electrode support layer in Example 2.

[0105] Example 22 The only difference between the preparation method of the half-cell in this example and that in Example 20 is that the half-cell semi-finished product is made from the electrode support layer in Example 3.

[0106] Examples 23-24 The only difference between the preparation methods of the half-cells in Examples 23 and 24 and those in Example 20 is that the temperature of the first sintering is different, as shown in Table 3.

[0107] Examples 25-26 The only difference between the preparation methods of the half-cells in Examples 25 and 26 and those in Example 20 is that the second sintering temperature is different, as shown in Table 3.

[0108] Comparative Example 20 The only difference between the preparation method of the half-cell in this example and that in Example 20 is that this example does not include the first sintering step.

[0109] Comparative Example 21 The only difference between the preparation method of the half-cell in this example and that in Example 20 is that the half-cell semi-finished product prepared by the electrode support layer in Comparative Example 1 is used.

[0110] Comparative Example 22 The only difference between the preparation method of the half-cell in this example and that in Example 20 is that the half-cell semi-finished product prepared by the electrode support layer in Comparative Example 2 is used.

[0111] Comparative Examples 23-24 The only difference between the preparation methods of the half-cells in Comparative Examples 23-24 and Example 20 is that the first sintering temperature is different, as shown in Table 3.

[0112] Comparative Examples 25-26 The only difference between the preparation methods of the half-cells in Comparative Examples 25-26 and Example 20 is that the second sintering temperature is different, as shown in Table 3.

[0113] The polarization impedance, upper limit of fuel utilization, and carbon deposition of the half-cells in Examples 20-26 and Comparative Examples 20-26 were tested respectively. The specific test methods are as follows: Polarization resistance: The cathode was prepared by screen printing and electrophoresis was performed using a platinum mesh. The anodic polarization resistance (ASR) was ≤0.15Ω·cm² at 800℃ (solartron 1260 test). Fuel utilization rate: After 1200 hours of constant current operation at a CH4 fuel flow rate of 20 mL / min, the upper limit of the utilization rate was measured to be above 88%; fuel utilization rate U f =I / I 理论 I 理论 =nzF, where n is the number of moles of reactant gas, z is the stoichiometric number of electron transfers in gas molecules during the reaction, and F is the Faraday constant; Long-term stability: After 1200 hours of constant current operation using a carbon-sulfur meter, the measured carbon deposit should be ≤0.20wt% (TPO test).

[0114] Table 3 Sintering temperature and half-cell test results

[0115] As shown in Table 3, compared with Comparative Examples 20-25, the half-cells in Examples 20-26 have lower polarization resistance and carbon deposition, and higher fuel efficiency, specifically: polarization resistance is 0.11-0.15 Ω·cm. 2 The upper limit of fuel utilization rate after 1200 hours is 88-91%, and the carbon deposition is 0.12-0.2%. Compared with Comparative Example 20, the half-cells in Examples 20-26, by employing a two-stage calcination method, can reduce the polarization resistance and carbon deposition of the half-cells and improve fuel utilization rate. In Comparative Example 23, the carbon deposition of the half-cell after 1200 hours of constant current operation is >1.0 wt%, resulting in a decrease in the upper limit of fuel utilization rate to 55%, a significant reduction in fuel utilization rate, which cannot meet the requirements of solid oxide fuel cells or solid oxide fuel electrolyzers.

[0116] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A half-cell, characterized in that: It includes an electrode support layer; the electrode support layer includes a first ceramic layer and a second ceramic layer stacked together; the first ceramic layer includes the following raw materials by mass percentage: ceramic powder 45~60%, first binder 7~12%, dispersant 0.1~0.5%, and solvent 27.5~47.5%; The first adhesive contains polyvinyl alcohol and polyacrylic acid, wherein the mass ratio of polyvinyl alcohol to polyacrylic acid is (1.5~4):1; The second ceramic layer comprises the following raw materials by mass percentage: 45-60% ceramic powder, 7-12% second binder, 0.1-0.5% dispersant, and 27.5-47.5% solvent; The second adhesive contains polyvinyl alcohol and polyacrylic acid, wherein the mass ratio of polyvinyl alcohol to polyacrylic acid is (0.75~1):1; The electrode support layer is prepared by a method including the following steps: mixing the raw materials for preparing the first ceramic layer and the second ceramic layer respectively to obtain the first ceramic slurry and the second ceramic slurry; The electrode support layer is obtained by sequentially coating a first ceramic slurry and a second ceramic slurry onto a substrate and then immersing it in a displacement solution for displacement treatment. The replacement solution contains ethanol and ethyl acetate in a volume ratio of (2~5):1; The half-cell also includes an anode functional layer and an electrolyte layer sequentially stacked on the electrode support layer; The half-cell is prepared by a method including the following steps: An anode functional layer and an electrolyte layer are screen-printed on the electrode support layer, and then calcined to obtain a semi-finished half-cell. The half-cell semi-finished product is immersed in an impregnation solution containing a catalyst precursor, then centrifuged, and then sintered. The sintering process involves a first sintering at 350-550°C, followed by a second sintering at 600-800°C.

2. The half-cell according to claim 1, characterized in that: The ceramic powder comprises NiO and yttrium oxide-stabilized zirconium oxide in a mass ratio of 1:(0.4~1); And / or, the dispersant includes at least one of ammonium polyacrylate, ammonium polycarboxylate, and polyethylene glycol; And / or, the solvent includes water.

3. The half-cell according to claim 1, characterized in that: The thickness ratio of the first ceramic layer to the second ceramic layer is (3~10):

1.

4. The half-cell according to any one of claims 1 to 3, characterized in that: The electrode support layer has at least one of the following characteristics: (a1) The porosity of the electrode support layer is ≥32%; (a2) The number of through holes in the electrode support layer accounts for more than 83% of the total number of holes; (a3) The bending strength of the electrode support layer is ≥294MPa.

5. The half-cell according to claim 1, characterized in that: The electrode support layer is loaded with a catalyst.

6. A battery, characterized in that: Includes the half-cell as described in any one of claims 1-5.

7. The battery according to claim 6, characterized in that: The battery includes a solid oxide fuel cell.

8. An electrolytic cell, characterized in that: Includes the half-cell as described in any one of claims 1-5.

9. The electrolytic cell according to claim 8, characterized in that: The electrolytic cell includes a solid oxide fuel electrolytic cell.

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