Manufacturing method for electrolyte sheet, electrolyte sheet and solid oxide battery

Abstract

The present invention relates to a manufacturing method for an electrolyte sheet, an electrolyte sheet and a solid oxide battery. The manufacturing method of the present invention comprises the following steps: 1) providing a raw material composition, wherein the raw material composition comprises an oxide powder and a crystal phase stabilizer powder, and the oxide, in a pure state, substantially exists in the form of a crystal phase that is stable at room temperature; 2) grinding the raw material composition to obtain a ground composition, wherein the particle size DV(50) of the oxide powder in the raw material composition is set to be A1, the particle size DV(50) of the ground composition is set to be B, and then B / A1=0.53-0.67; 3) forming the ground composition into a sheet; and 4) sintering the sheet, so as to obtain an electrolyte sheet comprising grains formed by stabilizing the oxide by the crystal phase stabilizer. The manufacturing method of the present invention shortens the production process, improves the production efficiency, and is more suitable for commercial production.

Description

A method for manufacturing an electrolyte sheet, the electrolyte sheet, and a solid oxide battery. Technical Field

[0001] This invention relates to the field of solid oxide battery technology. More specifically, this invention relates to a method for manufacturing an electrolyte sheet, an electrolyte sheet manufactured by the method, and a solid oxide battery comprising the electrolyte sheet. Background Technology

[0002] Solid oxide batteries (SOCs) are all-solid-state energy conversion devices that use solid oxides as electrolytes to directly convert chemical energy into electrical energy. Their most significant characteristic is direct energy conversion, unaffected by the Carnot cycle, achieving an energy conversion efficiency of over 60%, and thus possessing broad application prospects. Their basic structure mainly consists of a cathode, anode, and electrolyte. The electrolyte, which isolates gases and facilitates ion conduction, is the core component, and its quality directly determines the battery's electrochemical performance and long-term stability.

[0003] Currently, the commonly used materials for the electrolyte layer of solid oxide batteries (SOCs) are yttrium-stabilized zirconium oxide (YSZ), scandium-stabilized zirconium oxide (SSZ), and gadolinium-doped cerium oxide (GDC). Electrolyte powders require prior synthesis followed by high-temperature sintering, and finally, grinding to the required particle size to produce a qualified product. Electrolyte sheets are typically formed using a casting process, which involves thoroughly mixing YSZ powder with solvents, dispersants, binders, and plasticizers to create a casting slurry, followed by casting, drying, and high-temperature sintering to produce the electrolyte sheet. It is evident that the production process for electrolyte sheets is complex, has a long production cycle, and consumes a lot of energy. Summary of the Invention

[0004] The inventors of this invention discovered that the preparation of solid oxide fuel cell electrolyte powder and the casting of finished electrolyte sheets both require sintering at temperatures exceeding 1000°C for several hours. Furthermore, the sintered electrolyte powder needs to be ball-milled to obtain a suitable particle size. Therefore, the preparation process is energy-intensive and time-consuming. This invention addresses these problems.

[0005] According to a first aspect of the present invention, a method for manufacturing an electrolyte sheet is provided, comprising the following steps:

[0006] 1) Provide a raw material composition, wherein the raw material composition comprises an oxide powder and a crystal phase stabilizer powder, and the oxide exists substantially in its pure state as a stable crystal phase at room temperature.

[0007] 2) Grind the raw material composition to obtain a ground composition, wherein the particle size DV(50) of the oxide powder in the raw material composition is A1, and the particle size DV(50) of the ground composition is B, then B / A1 = 0.53-0.67 (preferably 0.60-0.63).

[0008] 3) The grinding composition is formed into a sheet.

[0009] 4) Sinter the sheet to obtain an electrolyte sheet containing the crystal phase stabilizer that stabilizes the oxide to form grains.

[0010] According to a second aspect of the invention, an electrolyte sheet is provided, manufactured by the method described in the first aspect, having a density of 4.8-5.9 g / cm³. 3 (Preferred concentration: 5.8-5.9 g / cm³) 3 The ionic conductivity is 0.018-0.032 S / cm (preferably 0.028-0.031 S / cm).

[0011] According to a third aspect of the present invention, a solid oxide battery is provided, comprising the electrolyte sheet described in the second aspect as an electrode.

[0012] Technical effect

[0013] The powder in the electrolyte precursor slurry provided by this invention is not the prepared electrolyte powder, but the oxide powder required for synthesizing the electrolyte powder. Taking YSZ electrolyte as an example, the powder in its slurry is yttrium oxide and zirconium oxide powder in appropriate proportions. Electrolyte molding is performed using tape casting. The thickness of a single electrolyte layer is controlled by the height of the scraper. If a thicker electrolyte support layer is required, it is prepared by multi-layer isostatic pressing, followed by high-temperature sintering. The thickness of the formed electrolyte can be controlled between 0.05mm and 1mm. The area of ​​the electrolyte sheet is controlled by cutting the green blank, with a maximum size of 250mm × 250mm. This invention is also applicable to commonly used electrolyte materials, such as scandium-stabilized zirconium oxide (SSZ) and gadolinium-doped cerium oxide (GDC).

[0014] According to the present invention, the preparation and casting of solid oxide fuel cell electrolyte powder both require sintering at high temperature for several hours, and the sintered electrolyte powder also needs to be ball-milled to obtain a suitable particle size. Therefore, the energy consumption during the preparation process is high. The present invention has good sintering activity and only requires one high-temperature sintering to prepare high-quality electrolyte sheets, which has outstanding energy-saving effect.

[0015] According to this invention, the two processes of electrolyte powder preparation and casting molding are integrated into a single production process, simplifying the production flow and making it more suitable for large-scale, commercial production. This will play a crucial supporting role in the rapid development of the solid oxide fuel cell industry in the future. Attached Figure Description

[0016] Figure 1 is a SEM image of the electrolyte sheet prepared in Example 1 after sintering at 1500°C.

[0017] Figure 2 is a SEM image of the electrolyte sheet prepared in Example 29 after sintering at 1400°C.

[0018] Figure 3 is a SEM image of the electrolyte sheet prepared in Comparative Example 1 after sintering at 1500℃.

[0019] Figure 4 shows the casting effect of the slurry prepared in Comparative Example 2.

[0020] Figure 5 is a SEM image of the electrolyte sheet prepared in Comparative Example 3 after sintering at 1500℃.

[0021] Figure 6 is a comparative XRD pattern of the electrolyte sheets prepared in Examples 1 and 29 and the finished powder prepared in Comparative Example 1. Detailed Implementation

[0022] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0023] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0024] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0025] In the context of this invention, all numerical values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numerical value.

[0026] In the context of this invention, unless otherwise specified, the term "substantially" means that deviations that are acceptable or considered reasonable to those skilled in the art are permitted, such as deviations within ±2%, ±1%, ±0.5%, or ±0.1%.

[0027] In the context of this invention, the method for measuring average particle size is to use a laser particle size analyzer to test the particle size distribution and then calculate its average value.

[0028] In the context of this invention, the particle size DV(50) is measured using a laser particle size analyzer, representing the particle diameter corresponding to a cumulative volume percentage of 50% in the volume distribution. The laser particle size analyzer test conditions are as follows: deionized water is used as the dispersion medium, sodium hexametaphosphate is used as the dispersant, a general model is used for analysis, the occlusion is 8%-12%, the scattering model is Mie, and the analysis sensitivity is in enhanced mode.

[0029] In the context of this invention, the specific surface area is measured using a specific surface area analyzer. The temperature must be constant at 22±3℃, the relative humidity strictly controlled at ≤45%, the sample weight ≥1.5g, and the particle size must be pulverized to ≤0.2mm to ensure uniform bulk density. The degassing temperature is controlled at 300–350℃, the adsorbed gas is high-purity nitrogen (purity ≥99.999%), the testing mode uses mesoporous materials, and the multi-point BET mode has an equilibrium time of 60s.

[0030] In the context of this invention, the density of the electrolyte sheet is measured using the water displacement method. The volume is determined by the mass difference before and after immersion. The electrolyte sheet is 2×2 cm in size. Before the water displacement test, the electrolyte sheet is boiled in water for 2 hours. ρ 水 =0.99704 g / cm³ 3 m 水 To determine the apparent mass of the solid when submerged in water, an analytical balance with an accuracy of ≥0.1mg was used for weighing, and a platinum wire with a diameter of ≤0.1mm was used for suspension to reduce additional buoyancy error.

[0031] In the context of this invention, the ionic conductivity is measured using the DC four-terminal method. Platinum electrodes are used to reduce ohmic resistance. An excitation current of 5 mA is applied alternately in both forward and reverse directions to eliminate thermoelectric potential drift. The electrolyte sheet used as the test sample measures 4 × 0.5 × 0.1 cm. The heating rate is 3 °C / min, and the ionic conductivity is measured at 400 / 500 / 600 / 700 / 800 °C for 40 min, within the range of 400-800 °C.

[0032] In the context of this invention, the SEM measurement method involves scanning the cross-section of the sample using a conventional scanning electron microscope. The specific testing method is as follows: accelerating voltage of 8 kV, observation magnification of 1000-5000x, working distance of 8-10 mm, detector of TE (non-tilted), probe current of 20 μA (Normal), and conductive treatment by W vapor deposition (3 minutes).

[0033] In the context of this invention, the method for measuring the crystal phase is to compare the XRD pattern obtained by commonly used X-ray diffraction with a standard card. The sample is ground to a particle size ≤45μm (passing through a 200-mesh sieve), forming a uniform powder without any grainy texture, and the dosage is ≥0.1g. The test surface must be flat and smooth, with a size of 1-2cm, and the sample must be dry. The scanning range (2θ) is 5°-70° (prioritizing the 30°–35° tetragonal phase characteristic peak region), the scanning step size is 0.01°, the scanning rate is 2° / min, and the counting time is 2s.

[0034] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this instruction manual are based on weight, and the pressure is gauge pressure.

[0035] In the context of this invention, any two or more embodiments or aspects of this invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of this invention.

[0036] According to one embodiment of the present invention, a method for manufacturing an electrolyte sheet is provided. According to the present invention, the electrolyte preparation process exhibits good sintering activity, and only requires a single high-temperature sintering process to produce a high-quality electrolyte sheet. This simplifies the production process, makes it more suitable for large-scale, commercial production, and also provides significant energy-saving effects. This method can be used to prepare an electrolyte support sheet, and can also be used as an electrolyte layer for co-firing in a half-cell to prepare a half-cell.

[0037] According to one embodiment of the present invention, the manufacturing method includes step 1): providing a raw material composition, wherein the raw material composition comprises oxide powder and crystal phase stabilizer powder. According to the present invention, the oxide exists in its pure state as a stable crystal phase at room temperature, that is, the oxide exists essentially in its original (e.g., unstabilized) crystal phase. In other words, the oxide powder is not a prepared electrolyte powder (e.g., stabilized electrolyte powder such as YSZ), but a raw material oxide powder required for synthesizing electrolyte powder; this is a significant difference between the present invention and the prior art. Furthermore, the phrase "exists in its pure state as a stable crystal phase at room temperature" specifically refers to, for example, when the oxide powder is zirconium oxide powder, its pure state stable crystal phase at room temperature is a monoclinic phase.

[0038] According to one embodiment of the present invention, the particle size DV(50) of the oxide powder is 0.15-1.5 μm (preferably 0.4-1.0 μm) and the specific surface area is less than 25 m² / g (preferably 5-20 m² / g). The inventors of the present invention have found that when the particle size DV(50) of the oxide powder is greater than the upper limit specified in the present invention, the fusion between the oxide powder and the crystal phase stabilizer powder will be insufficient, the sintering activity of the powder will be poor, the electrolyte sheet will not be dense enough, and the ionic conductivity will not meet the requirements. When the particle size DV(50) of the oxide powder is less than the lower limit specified in the present invention, the slurry viscosity will be high, and problems such as inability to cast, cracking of the cast green body, or cracking during sintering will occur. In addition, the inventors of this invention have also discovered that the specific surface area of ​​the oxide powder has a significant impact on the viscosity and casting effect of the prepared casting slurry. Through experimental verification, it has been found that only within the above-mentioned numerical range can high-quality electrolyte sheets be prepared. However, if the numerical range is exceeded, various problems such as inability to cast, cracking of the cast green body, sintering cracking, and non-density of the electrolyte sheet will occur, making it impossible to prepare qualified electrolyte sheets.

[0039] According to one embodiment of the present invention, the particle size DV(50) of the phase stabilizer powder is 0.15-1.4 μm (preferably 0.4-1.0 μm) and the specific surface area is less than 35 m² / g (preferably 10-30 m² / g). The inventors of the present invention have found that when the particle size DV(50) of the phase stabilizer powder is greater than the upper limit specified in the present invention, the fusion between the oxide powder and the phase stabilizer powder will be insufficient, the sintering activity of the powder will be poor, the electrolyte sheet will not be dense enough, and the ionic conductivity will not meet the requirements. When the particle size DV(50) of the phase stabilizer powder is less than the lower limit specified in the present invention, the slurry viscosity will be high, and problems such as inability to cast, cracking of the cast green body, or cracking during sintering will occur. In addition, the inventors of this invention have also discovered that the specific surface area of ​​the crystal phase stabilizer powder has a significant impact on the viscosity and casting effect of the prepared casting slurry. Through experimental verification, it has been found that only within the above-mentioned numerical range can high-quality electrolyte sheets be prepared. However, if the numerical range is exceeded, various problems such as inability to cast, cracking of the casting green blank, sintering cracking, and non-density of the electrolyte sheet will occur, making it impossible to prepare qualified electrolyte sheets.

[0040] According to one embodiment of the present invention, in step 1), the ratio of the particle size DV(50) of the oxide powder to the particle size DV(50) of the crystal phase stabilizer powder is 0.2-8. The inventors of this invention have found that when the particle size DV(50) ratio does not meet the numerical range specified in this invention, the particle size matching degree between the oxide powder and the crystal phase stabilizer powder is poor, which may lead to insufficient mutual fusion after grinding in step 2), insufficient sintering of the electrolyte sheet, and failure to meet the required ionic conductivity.

[0041] According to one embodiment of the present invention, the oxide can be any oxide conventionally used in the manufacture of electrolyte sheets in the art, without particular limitation. For example, the oxide is selected from at least one of zirconium oxide, cerium oxide, and bismuth oxide (preferably selected from at least one of zirconium oxide and cerium oxide). The crystal phase stabilizer can be any crystal phase stabilizer conventionally used in the manufacture of electrolyte sheets in the art, without particular limitation. For example, the crystal phase stabilizer is selected from at least one of yttrium oxide, scandium oxide, gadolinium oxide, samarium oxide, barium oxide, and strontium oxide (preferably selected from at least one of yttrium oxide, gadolinium oxide, and barium oxide). Furthermore, for example, the molar ratio of the oxide powder to the crystal phase stabilizer powder is 80-98:2-20 (preferably 85-95:5-15).

[0042] According to one embodiment of the present invention, the raw material composition further includes a solvent and a dispersant. Here, the solvent and the dispersant can be any solvent and dispersant conventionally used in the manufacture of electrolyte tablets in the art, without particular limitation. For example, the solvent is selected from at least one of ethanol, methyl ethyl ketone (MEK), toluene, and benzene (preferably selected from at least one of MEK and ethanol). For example, the dispersant is selected from at least one of triethanolamine, oleyl alcohol, and fish oil (preferably selected from at least one of triethanolamine and fish oil). Furthermore, based on the total weight of the oxide powder and the crystal phase stabilizer powder, the amount of solvent is 30-55% (preferably 40-50%), and the amount of dispersant is 0.5-10 wt% (preferably 3-5 wt%).

[0043] According to one embodiment of the present invention, the manufacturing method further includes step 2): grinding the raw material composition to obtain a grinding composition, also known as a slurry. According to the present invention, let the particle size DV(50) of the oxide powder in the raw material composition be A1, and let the particle size DV(50) of the grinding composition be B, then B / A1 = 0.53-0.67 (preferably 0.60-0.63). The inventors of the present invention have found that when B / A1 is greater than the upper limit specified in the present invention, the fusion of the oxide powder and the crystal phase stabilizer powder is insufficient, the sintering activity of the powder is poor, the electrolyte sheet is not dense enough, and the ionic conductivity cannot meet the requirements. Conversely, when B / A1 is less than the lower limit specified in the present invention, the slurry viscosity is high, leading to problems such as inability to cast, cracking of the cast green body, or cracking during sintering. The inventors of this invention have also discovered that by ensuring the B / A1 ratio meets the numerical range specified in this invention, the technical problems existing in the prior art when using finished electrolyte powder as raw material can be solved. This reduces production energy consumption and shortens the production process, while simultaneously producing electrolyte sheets with densities and ionic conductivity comparable to or even superior to those of the prior art. Without any theoretical limitations, the inventors believe that by matching the initial particle size distribution of the oxide powder with the ball milling time, the B / A1 value can be precisely controlled. This allows the oxide powder to be used directly as a raw material for slurry preparation, achieving integrated production of electrolyte powder preparation and molding / sintering. It eliminates the need for the high-temperature sintering and granulation required in the prior art for preparing electrolyte powder and slurry preparation. Therefore, this invention saves energy consumption in electrolyte powder sintering and ball milling granulation, significantly reducing the manufacturing cost of electrolyte sheets. Without being limited by any theoretical constraints, the inventors of this invention further believe that by controlling the B / A1 ratio within the numerical range specified in this invention, the two raw material powders, during ball milling, undergo intense impact, compression, and shearing, not only achieving thorough and uniform mixing and matching of particle morphology and particle size refinement, but also generating an activation effect beneficial to subsequent sintering and solid solution treatment. Specifically, firstly, a large number of lattice defects, such as dislocations and vacancies, are generated within the powder particles, and a large number of amorphous or distorted layers are formed on the particle surface. These defects provide rapid pathways for subsequent atomic diffusion. Secondly, the activation energy of the reaction is reduced: due to the changes in particle size, increased defects, and larger contact area caused by ball milling, the energy barrier (activation energy) required for the solid solution reaction is significantly reduced, resulting in a small amount of pre-solid solution reaction on the surface of the raw material powder. Therefore, while the existing two-step method generates this solid solution reaction in the first step through sintering, this invention generates an activation effect beneficial to the solid solution reaction through grinding, and produces a small amount of pre-solid solution reaction on the powder surface, thus successfully completing a one-step method for the first time in the art. As a "success", it means that the electrolyte sheet manufactured by the one-step method of the present invention has comparable or even superior performance compared with the two-step method of the prior art.

[0044] According to one embodiment of the present invention, let the particle size DV(50) of the crystal phase stabilizer powder in the raw material composition be A2, and let the particle size DV(50) of the grinding composition be B, then B / A2 = 0.57-0.67 (preferably 0.60-0.63). The inventors of the present invention have found that when B / A2 is greater than the upper limit specified in the present invention, the fusion of the oxide powder and the crystal phase stabilizer powder is not sufficient, the sintering activity of the powder is poor, the electrolyte sheet is not dense enough, and the ionic conductivity cannot meet the requirements. When B / A2 is less than the lower limit specified in the present invention, the slurry viscosity is high, and problems such as inability to cast, cracking of the cast green body, or cracking during sintering may occur.

[0045] According to one embodiment of the present invention, in step 2), the particle size DV(50) of the grinding composition is 0.10-0.80 μm (preferably 0.25-0.60 μm). The inventors of the present invention have found that when the particle size DV(50) of the grinding composition is greater than the upper limit specified in the present invention, the fusion of the oxide powder and the crystal phase stabilizer powder is not sufficient, the sintering activity of the powder is poor, the electrolyte sheet is not dense enough, and the ionic conductivity cannot meet the requirements. When the particle size DV(50) of the grinding composition is less than the lower limit specified in the present invention, the slurry viscosity is high, and problems such as inability to cast, cracking of the cast green body, or cracking during sintering may occur.

[0046] According to one embodiment of the present invention, the grinding is carried out in a ball mill for a grinding time of 5-48 hours (preferably 18-24 hours). The inventors of the present invention have found that within the above-mentioned ball milling time range, the dispersion effect of the powder can reach a relatively ideal state, while not wasting too much preparation time.

[0047] According to a preferred embodiment of the present invention, the grinding is performed according to the following steps: 2-1) grinding the raw material composition for 5-48 hours (preferably 18-24 hours) to obtain a pre-ground composition; 2-2) adding at least one selected from plasticizers and binders to the pre-ground composition, and continuing grinding for 2-20 hours (preferably 4-10 hours) to obtain the ground composition. The inventors of the present invention have discovered that within the above-mentioned ball milling time range, the slurry uniformity, viscosity, and flowability can reach a relatively ideal state, while ensuring production efficiency.

[0048] According to one embodiment of the present invention, in step 2-1), the raw material composition further includes at least one selected from solvent and dispersant, preferably including both solvent and dispersant. The inventors of the present invention have discovered that by introducing the solvent and dispersant in step 2-1), and then introducing the plasticizer and binder in step 2-2), the optimal fusion effect between the oxide powder and the crystal phase stabilizer powder can be achieved, ultimately obtaining a dense electrolyte sheet with high ionic conductivity. The inventors of the present invention have also discovered that, to further enhance these technical effects, it is preferred that in step 2-1), if the particle size DV(50) of the pre-grinding composition is A3, and the particle size DV(50) of the grinding composition is B, then B / A3 = 0.80-0.90, preferably 0.83-0.86.

[0049] According to one embodiment of the present invention, the plasticizer and the binder can be any plasticizer and binder conventionally used in the manufacture of electrolyte sheets in the art, without particular limitation. For example, the plasticizer is selected from at least one of dibutyl phthalate, di-n-octyl phthalate, and polyethylene glycol (preferably selected from at least one of dibutyl phthalate, polyethylene glycol, and butylphthalide). For example, the binder is selected from at least one of polyvinyl butyral, polyvinyl alcohol, and polypropylene (preferably selected from at least one of polyvinyl butyral and polypropylene). Furthermore, based on the total weight of the oxide powder and the crystal phase stabilizer powder, the amount of the plasticizer is 3-15 wt% (preferably 5-10 wt%), and the amount of the binder is 3-20 wt% (preferably 5-10%).

[0050] According to one embodiment of the present invention, the manufacturing method further includes step 3): forming the grinding composition into a sheet.

[0051] According to one embodiment of the present invention, the molding can be any molding method conventionally used in the art for manufacturing electrolyte sheets, without particular limitation, but casting molding is preferred. For example, the operating conditions for casting molding include: casting speed of 0.10-1 m / min, green thickness of 90-120 μm, green drying temperature of room temperature to 60°C, green layer count of 2-8 layers, green pressing temperature of 65-85°C, green pressing pressure of 12-30 MPaG, and green pressing time of 3-15 min.

[0052] According to one embodiment of the present invention, the manufacturing method further includes step 4): sintering the sheet to obtain an electrolyte sheet containing grains formed by stabilizing the oxide with the crystal phase stabilizer. The inventors of the present invention have found that the average particle size of the grains, as determined by SEM, is 0.5-5 μm (preferably 0.5-1.5 μm). The inventors of the present invention have also found that the powder in the casting slurry prepared by the present invention is the raw material powder that has not been sintered. During the sintering process, it first forms a stable cubic phase, and then the grains grow and expel pores, forming a dense electrolyte layer, thus solving the grain growth problem of the finished powder during the molding and sintering process.

[0053] According to one embodiment of the present invention, the sintering temperature is 1450-1600℃ (preferably 1500-1550℃). The inventors of the present invention have discovered that a dense electrolyte layer can be formed and a certain ionic conductivity can be guaranteed at the above sintering temperature, with the highest ionic conductivity occurring at sintering temperatures in the 1500-1550℃ range. Furthermore, the inventors of the present invention have discovered that existing technologies first require sintering electrolyte powder at a high temperature of 1000℃ to prepare the electrolyte powder, then ball milling to prepare electrolyte raw material powder of a suitable particle size for use as electrolyte raw material in slurry preparation, and after tape casting, sintering at a high temperature of 1500℃-1600℃ is required to prepare electrolyte sheets. Therefore, the present invention can at least save energy consumption in the 1000℃ sintering preparation and ball milling granulation of electrolyte powder.

[0054] According to one embodiment of the present invention, the sintering operating conditions further include: a sintering time of 1-6 hours (preferably 2-4 hours) and a sintering pressing pressure of 25-100 PaG (preferably 50-80 PaG).

[0055] According to one embodiment of the present invention, the density of the electrolyte sheet is 4.8-5.9 g / cm³. 3 (Preferred concentration: 5.8-5.9 g / cm³) 3 The electrolyte layer has a thickness of 0.05-1 mm (preferably 0.10-0.5 mm) and an ionic conductivity of 0.018-0.032 S / cm (preferably 0.028-0.031 S / cm). This invention achieves a dense electrolyte layer under the aforementioned density conditions, ensuring both airtightness and high ionic conductivity. Under the preferred thickness conditions, the green body produced after casting has a high yield, is free of defects such as bubbles and cracks, and exhibits high production efficiency.

[0056] According to one embodiment of the present invention, the XRD pattern of the electrolyte sheet matches the diffraction peak positions of the 8YSZ cubic phase structure in the standard card, and substantially does not show diffraction peaks of non-cubic phases. This indicates that although the present invention combines powder preparation and molding synthesis into a one-step process to obtain the electrolyte sheet, a high-quality 8YSZ cubic phase structure is obtained.

[0057] As a more specific example, the manufacturing method of the present invention can be carried out according to the following steps.

[0058] The first step is to prepare the powders needed for the electrolyte sheet. Taking YSZ electrolyte as an example, yttrium oxide (8% mol) and zirconium oxide powder are required. This invention is also applicable to commonly used electrolyte materials, such as scandium-stabilized zirconium oxide (SSZ) and gadolinium-doped cerium oxide (GDC). These powders can be purchased as commercially available products or prepared by oneself. The preparation methods are mature and stable, and can be obtained from relevant literature and books.

[0059] The second step is to prepare the electrolyte precursor casting slurry. First, the powder prepared in the first step, along with the solvent and dispersant, is ball-milled for 18-24 hours to ensure uniform dispersion. The target electrolyte can be any of the commonly used electrolyte materials such as YSZ, SSZ, or GDC. Then, based on the above slurry, a plasticizer and binder are added, and ball milling continues for 4-10 hours to complete the preparation of the casting slurry.

[0060] The third step involves sieving the prepared slurry through a 50-100 mesh sieve to remove large impurities. After degassing under vacuum, the electrolyte layer is cast on a casting machine to form an electrolyte precursor green body of a certain thickness. Once the green body is dry, it is peeled off from the casting receiving tape and cut into the required shape and size.

[0061] The fourth step involves stacking the electrolyte green preforms prepared in the third step, selecting the appropriate number of layers according to the required electrolyte thickness, placing them in a vacuum packaging bag and evacuating them, and finally pressing them together in a warm isostatic press.

[0062] The fifth step involves placing the hot-pressed green sheet from the fourth step into a sintering furnace for high-temperature sintering. To ensure the flatness of the electrolyte sheet, it needs to be pressed and sintered. If the pressing is too light, the flatness of the electrolyte sheet will not meet the requirements; if it is too heavy, the electrolyte sheet will break.

[0063] Example

[0064] The present invention will be further described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0065] All raw materials, reagents, instruments and equipment used in the following examples and comparative examples can be purchased commercially or prepared by conventional methods existing in the art.

[0066] Example 1

[0067] 3.437g of yttrium oxide powder and 21.563g of zirconia powder (monoclinic phase) were weighed and added to a ball mill jar. The zirconia powder had a particle size DV(50) of 0.5μm and a specific surface area of ​​10㎡ / g, while the yttrium oxide powder had a particle size DV(50) of 0.5μm and a specific surface area of ​​20㎡ / g. 12.6g of butanone and 8.4g of ethanol were added as a mixed solvent, and 0.6g of triethanolamine (TEA) dispersant was added. The mixture was ball-milled for 24 hours to disperse the powder evenly. Then, based on the pre-ground slurry, 1g each of dibutyl phthalate (DOP) and polyethylene glycol 400 (PEG) in a 1:1 ratio were added as plasticizers. Finally, 1.7g of polyvinyl butyral (PVB) binder was added, and the mixture was ball-milled for another 5 hours until the particle size DV(50) of the finished slurry reached 0.31μm, thus completing the preparation of the electrolyte layer precursor casting slurry.

[0068] According to Example 1, B / A1 = 0.62, B / A2 = 0.62, and B / A3 = 0.85.

[0069] The prepared slurry was sieved through a 100-mesh sieve to remove large impurities. After degassing under a vacuum of -90 kPa for 20 minutes, the electrolyte layer was cast on a casting machine at a casting speed of 0.3 m / min. The green body drying conditions were 30°C and the doctor blade height was 500 μm, producing an electrolyte precursor green body with a thickness of 120 μm. After the cast green body dried, it was peeled off from the casting receiving tape and cut into 6.4 cm × 6.4 cm electrolyte sheet green bodies.

[0070] The prepared electrolyte green preforms were stacked in two layers, placed in a vacuum packaging bag and vacuumed, and finally placed in a warm isostatic press for molding. The warm isostatic pressing temperature was 75℃, the pressure was 18MPaG, and the hot pressing time was 10min.

[0071] Finally, the hot-pressed green blank was placed in a sintering furnace for high-temperature sintering at 1500℃ for 2 hours. To ensure the flatness of the electrolyte sheet, it needed to be pressed and sintered, with the pressure generated by the weight of the pressed sheet reaching 60 PaG. SEM (Figure 2) and XRD (Figure 3) tests were performed on the sintered electrolyte sheet, revealing that a sintering temperature of 1500℃ could achieve a dense sintering. The electrolyte sheet had a thickness of 0.15 mm and a density of 5.87 g / cm³. 3 The XRD results show that the impurity peaks of zirconia have been eliminated (consistent with the test results of solid-state ball-milled YSZ powder sintered at 1500℃), indicating that the yttrium oxide doping is sufficient. The average grain size of YSZ grains measured by SEM is 1.2 μm. Ionic conductivity tests at 800℃ yielded a result of 0.032 S / cm.

[0072] Calculations show that the total energy consumption of this invention in manufacturing electrolyte sheets is 23 kWh, and the total manufacturing time is 70 hours. In contrast, using existing technologies with similar performance, under the same raw material conditions, the process involves ball milling and mixing followed by sintering at 1000°C to prepare electrolyte powder, then ball milling to prepare electrolyte powder raw materials with suitable particle size, and finally preparing a casting slurry for casting and sintering at 1500°C to prepare electrolyte sheets. This method consumes as much as 42 kWh and takes as long as 110 hours. This comparison demonstrates that this invention has significant energy-saving and time-saving effects compared to existing technologies.

[0073] Example 2

[0074] Same as Example 1, except that B / A1 = 0.61. The electrolyte sheet is sintered densely with a density of 5.88 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 1.18 μm. Ionic conductivity was measured at 800℃, and the result was 0.03 S / cm.

[0075] Example 3

[0076] Same as Example 1, except that B / A1 = 0.63. The electrolyte sheet is sintered densely with a density of 5.86 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 1.23 μm. Ionic conductivity was measured at 800℃, and the result was 0.031 S / cm.

[0077] Example 4

[0078] Same as Example 1, except that B / A1 = 0.55. The electrolyte sheet is sintered densely with a density of 5.89 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 1.16 μm. Ionic conductivity was measured at 800℃, and the result was 0.027 S / cm.

[0079] Example 5

[0080] Same as Example 1, except that B / A1 = 0.65. The electrolyte sheet is sintered densely with a density of 5.83 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 1.3 μm. Ionic conductivity was measured at 800℃, and the result was 0.026 S / cm.

[0081] Example 6

[0082] Similar to Example 1, the only difference being that the sintering temperature of the electrolyte sheet was 1580°C. The electrolyte sheet was sintered to a dense state with a density of 5.88 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 2.05 μm. Ionic conductivity was measured at 800℃, and the result was 0.024 S / cm.

[0083] Example 7

[0084] Same as Example 1, except that B / A2 = 0.52. The electrolyte sheet was not densely sintered, with a density of 4.7 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 2.4 μm. Ionic conductivity was measured at 800℃, and the result was 0.022 S / cm.

[0085] Example 8

[0086] Same as Example 1, except that B / A2 = 0.72. The electrolyte sheet is sintered densely with a density of 5.87 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.8 μm. Ionic conductivity was measured at 800 °C, and the result was 0.023 S / cm.

[0087] Example 9

[0088] Similar to Example 1, the only difference being that the particle size DV(50) of the finished slurry is 0.08 μm. The electrolyte sheet is sintered densely with a density of 5.84 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.32 μm. Ionic conductivity was measured at 800℃, and the result was 0.021 S / cm.

[0089] Example 10

[0090] Similar to Example 1, the only difference being that the particle size DV(50) of the finished slurry is 0.15 μm. The electrolyte sheet is sintered densely with a density of 5.8 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.48 μm. Ionic conductivity was measured at 800 °C, and the result was 0.023 S / cm.

[0091] Example 11

[0092] Similar to Example 1, the only difference being that the particle size DV(50) of the finished slurry is 0.69 μm. The electrolyte sheet is sintered densely with a density of 5.64 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 1.83 μm. Ionic conductivity was measured at 800℃, and the result was 0.022 S / cm.

[0093] Example 12

[0094] Similar to Example 1, the only difference being that the particle size DV(50) of the finished slurry is 0.85 μm. The electrolyte sheet is sintered densely with a density of 5.15 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 2.46 μm. Ionic conductivity was measured at 800 °C, and the result was 0.02 S / cm.

[0095] Example 13

[0096] Same as Example 1, except that B / A3 = 0.95. The electrolyte sheet is sintered densely with a density of 5.9 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.18 μm. Ionic conductivity was measured at 800℃, and the result was 0.019 S / cm.

[0097] Example 14

[0098] Same as Example 1, except that the particle size DV(50) of the zirconia powder is 0.12 μm. The electrolyte sheet is sintered densely with a density of 5.9 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.35 μm. Ionic conductivity was measured at 800 °C, and the result was 0.022 S / cm.

[0099] Example 15

[0100] Same as Example 1, except that the particle size DV(50) of the zirconia powder is 0.30 μm. The electrolyte sheet is sintered densely with a density of 5.9 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.92 μm. Ionic conductivity was measured at 800℃, and the result was 0.024 S / cm.

[0101] Example 16

[0102] Same as Example 1, except that the particle size DV(50) of the zirconia powder is 1.3 μm. The electrolyte sheet is sintered densely with a density of 5.4 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 2.1 μm. Ionic conductivity was measured at 800℃, and the result was 0.023 S / cm.

[0103] Example 17

[0104] Same as Example 1, except that the particle size DV(50) of the zirconia powder is 1.8 μm. The electrolyte sheet is sintered densely with a density of 5.18 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 2.5 μm. Ionic conductivity was measured at 800℃, and the result was 0.02 S / cm.

[0105] Example 18

[0106] Same as Example 1, except that B / A3 = 0.75. The electrolyte sheet was sintered to a basically dense state, with a density of 5.04 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 3.46 μm. Ionic conductivity was measured at 800 °C, and the result was 0.018 S / cm.

[0107] Example 19

[0108] Same as Example 1, except that the specific surface area of ​​the zirconia powder is 50 m² / g. The electrolyte sheet is sintered densely with a density of 5.89 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.33 μm. Ionic conductivity was measured at 800 °C, and the result was 0.024 S / cm.

[0109] Example 20

[0110] Same as Example 1, except that the specific surface area of ​​the zirconia powder is 4 m² / g. The electrolyte sheet is sintered densely with a density of 5.58 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.89 μm. Ionic conductivity was measured at 800℃, and the result was 0.02 S / cm.

[0111] Example 21

[0112] Same as Example 1, except that the particle size DV(50) of the crystal phase stabilizer powder is 0.10 μm. The electrolyte sheet is sintered densely with a density of 5.88 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.54 μm. Ionic conductivity was measured at 800℃, and the result was 0.021 S / cm.

[0113] Example 22

[0114] Same as Example 1, except that the particle size DV(50) of the crystal phase stabilizer powder is 0.30 μm. The electrolyte sheet is sintered densely with a density of 5.88 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 2.4 μm. Ionic conductivity was measured at 800℃, and the result was 0.023 S / cm.

[0115] Example 23

[0116] Similar to Example 1, the only difference being that the particle size DV(50) of the crystal phase stabilizer powder is 1.2 μm. The electrolyte sheet is sintered to a basically dense state with a density of 5.41 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 2.21 μm. Ionic conductivity was measured at 800℃, and the result was 0.022 S / cm.

[0117] Example 24

[0118] Similar to Example 1, the only difference being that the particle size DV(50) of the crystal phase stabilizer powder was 1.8 μm. The electrolyte sheet was sintered to a basically dense state with a density of 5.32 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 2.33 μm. Ionic conductivity was measured at 800℃, and the result was 0.019 S / cm.

[0119] Example 25

[0120] Same as Example 1, except that the specific surface area of ​​the crystal phase stabilizer powder is 40 m² / g. The electrolyte sheet is sintered densely with a density of 5.88 g / cm³. 3The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.46 μm. Ionic conductivity was measured at 800 °C, and the result was 0.024 S / cm.

[0121] Example 26

[0122] Same as Example 1, except that the specific surface area of ​​the crystal phase stabilizer powder is 5 m² / g. The electrolyte sheet is sintered densely with a density of 5.73 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 0.74 μm. Ionic conductivity was measured at 800 °C, and the result was 0.019 S / cm.

[0123] Example 27

[0124] Similar to Example 1, the only difference being the use of a stirred mixing device in the slurry preparation process, which resulted in a longer grinding time. The electrolyte sheet was sintered densely with a density of 5.84 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 1.17 μm. Ionic conductivity was measured at 800 °C, and the result was 0.023 S / cm.

[0125] Example 28

[0126] Similar to Example 1, the only difference is that all the materials contained in the slurry are placed into the ball mill jar at once to prepare the casting slurry, instead of ball milling the slurry in two steps, i.e., there is no pre-grinding step. The electrolyte sheet is sintered densely with a density of 5.8 g / cm³. 3 The diffraction peaks of the cubic phase structure are consistent, and virtually no diffraction peaks of the non-cubic phase are observed. The YSZ grain size is 1.24 μm. Ionic conductivity was measured at 800℃, and the result was 0.023 S / cm.

[0127] Example 29

[0128] Similar to Example 1, the only difference was that the sintering temperature of the electrolyte sheet was 1400℃. SEM (Figure 2) and XRD (Figure 6) tests were performed on the sintered electrolyte sheet, revealing that the sintering temperature of 1400℃ was insufficient to achieve a dense sinter, resulting in the presence of numerous pores and a density of 5.1 g / cm³. 3 The XRD results show that the impurity peaks of zirconia are still quite obvious, indicating that the doping is not sufficient. The YSZ grain size is 0.8 μm. Ionic conductivity was measured at 800℃, and the result was 0.018 S / cm.

[0129] Example 30

[0130] Similar to Example 1, the only difference being that the sintering temperature of the electrolyte sheet was 1650°C. The electrolyte sheet was sintered to a dense state with a density of 5.89 g / cm³. 3 The diffraction peaks of the cubic phase structure are in good agreement, and there are virtually no diffraction peaks of the non-cubic phase. The YSZ grain size is 2.3 μm. Over-sintering caused by excessively high sintering temperature resulted in excessively large grains, a significant decrease in ionic conductivity, and the product could not be used normally.

[0131] Example 31

[0132] Similar to Example 1, except that the ratio of the particle size DV(50) of the oxide powder to the particle size DV(50) of the crystal phase stabilizer powder is 9, and the ionic conductivity of the oxide powder was tested at 800°C, and the result was 0.022 s / cm.

[0133] Example 32

[0134] Similar to Example 1, except that the ratio of the particle size DV(50) of the oxide powder to the particle size DV(50) of the crystal phase stabilizer powder is 0.15, and the ionic conductivity of the oxide powder was tested at 800°C, and the result was 0.021 s / cm.

[0135] Comparative Example 1

[0136] Similar to Example 1, the only difference is that 8YSZ powder was first prepared by ball milling followed by sintering, and then sand milled to prepare a finished powder with a particle size DV(50) of 0.5 μm and a specific surface area of ​​10 m² / g. Then, the same slurry casting method was used, and finally, the electrolyte sheet was prepared under the same sintering conditions of 1500℃. The sintered 8YSZ powder had poor sintering activity, therefore the electrolyte sheet had slightly poor sintering density, with a small number of unclosed pores between the grains (see Figure 3), and a density of 5.7 g / cm³. 3 The ionic conductivity was tested at 800℃, and the result was 0.03 S / cm.

[0137] After calculation, the preparation method of Comparative Example 1 has a total energy consumption of up to 42 kWh and a total manufacturing time of up to 110 hours.

[0138] Comparative Example 2

[0139] Same as Example 1, except that B / A1 = 0.48. When preparing the casting slurry, the slurry viscosity was high, and the green body prepared after casting was uneven (see Figure 4), making it impossible to further sinter and prepare electrolyte sheets.

[0140] Comparative Example 3

[0141] Similar to Example 1, the only difference is that B / A1 = 0.72. The impurity peaks of zirconium oxide are still quite pronounced, indicating insufficient doping. Simultaneously, the powder sintering activity is poor, resulting in insufficiently dense sintering of the electrolyte sheet (see Figure 5), with a density of 4.6 g / cm³. 3 It does not meet the requirements for use in isolating gases. Ionic conductivity was tested at 800℃, and the result was 0.016 S / cm.

[0142] Comparative Example 4

[0143] Similar to Example 1, the only difference is that yttrium oxide powder and zirconium oxide powder are ground and prepared into separate slurries, then mechanically mixed together, and finally the mixture is directly used to cast electrolyte sheets. The impurity peaks of zirconium oxide are still quite obvious, indicating insufficient doping. Simultaneously, the powder sintering activity is poor, resulting in insufficiently dense sintering of the electrolyte sheet, with a density of 4.5 g / cm³. 3 It does not meet the requirements for use in isolating gases. Ionic conductivity was tested at 800℃, and the result was 0.014 S / cm.

Claims

1. A method for manufacturing an electrolyte sheet, comprising the following steps: 1) Provide a raw material composition, wherein the raw material composition comprises an oxide powder and a crystal phase stabilizer powder, and the oxide exists substantially in its pure state as a stable crystal phase at room temperature. 2) Grind the raw material composition to obtain a ground composition, wherein the particle size DV(50) of the oxide powder in the raw material composition is A1, and the particle size DV(50) of the ground composition is B, then B / A1 = 0.53-0.67 (preferably 0.60-0.63). 3) The grinding composition is formed into a sheet. 4) Sinter the sheet to obtain an electrolyte sheet containing the crystal phase stabilizer that stabilizes the oxide to form grains.

2. The manufacturing method according to claim 1, wherein the oxide is selected from at least one of zirconium oxide, cerium oxide, and bismuth oxide, preferably selected from at least one of zirconium oxide and cerium oxide, and the crystal phase stabilizer is selected from at least one of yttrium oxide, scandium oxide, gadolinium oxide, samarium oxide, barium oxide, and strontium oxide, preferably selected from at least one of yttrium oxide, gadolinium oxide, and barium oxide.

3. The manufacturing method according to claim 1, wherein the molar ratio of the oxide powder to the crystal phase stabilizer powder is 80-98:2-20, preferably 85-95:5-15.

4. The manufacturing method according to claim 1, wherein the particle size DV(50) of the crystal phase stabilizer powder in the raw material composition is A2, and the particle size DV(50) of the grinding composition is B, then B / A2 = 0.57-0.67 (preferably 0.60-0.63).

5. The manufacturing method according to claim 1, wherein in step 2), the particle size DV(50) of the grinding composition is 0.10-0.80 μm (preferably 0.25-0.60 μm).

6. The manufacturing method according to claim 1, wherein in step 1), the ratio of the particle size DV(50) of the oxide powder to the particle size DV(50) of the crystal phase stabilizer powder is 0.2-8.

7. The manufacturing method according to claim 1, wherein in step 1), the particle size DV(50) of the oxide powder is 0.15-1.5 μm (preferably 0.40-1.0 μm).

8. The manufacturing method according to claim 1, wherein in step 1), the specific surface area of ​​the oxide powder is less than 25 m² / g (preferably 5-20 m² / g).

9. The manufacturing method according to claim 1, wherein in step 1), the particle size DV(50) of the crystal phase stabilizer powder is 0.15-1.4 μm (preferably 0.40-1.0 μm).

10. The manufacturing method according to claim 1, wherein in step 1), the specific surface area of ​​the crystal phase stabilizer powder is less than 35 m² / g (preferably 10-30 m² / g).

11. The manufacturing method according to claim 1, wherein in step 2), the grinding is carried out in a ball mill for a grinding time of 5-48 hours (preferably 18-24 hours) and the ball mill speed is 200-600 r / min.

12. The manufacturing method of claim 1, wherein step 2) comprises the following steps: 2-1) Grind the raw material composition for 5-48 hours (preferably 18-24 hours) to obtain a pre-ground composition. 2-2) Add at least one selected from plasticizers and binders to the pre-grinding composition and continue grinding for 2-20 hours (preferably 4-10 hours) to obtain the grinding composition.

13. The manufacturing method of claim 10, wherein in step 2-1), the raw material composition further includes at least one selected from solvents and dispersants.

14. The manufacturing method according to claim 10, wherein in step 2-1), if the particle size DV(50) of the pre-grinding composition is A3 and the particle size DV(50) of the grinding composition is B, then B / A3 = 0.80-0.90 (preferably 0.83-0.86).

15. The manufacturing method of claim 1, wherein in step 4), the operating conditions of the sintering include: The sintering temperature is 1450-1600℃ (preferably 1500-1550℃), the sintering time is 1-6h (preferably 2-4h), and the sintering pressing pressure is 25-100PaG (preferably 50-80PaG).

16. The manufacturing method of claim 1, wherein in step 1), the oxide is zirconium oxide and the crystal phase is a monoclinic phase.

17. The manufacturing method of claim 1, wherein in step 4), the average particle size of the grains by SEM is 0.5-5 μm (preferably 0.5-1.5 μm).

18. An electrolyte sheet manufactured by the manufacturing method according to any one of claims 1 to 17, having a density of 4.8 to 5.9 g / cm3 3 (5.8 to 5.9 g / cm3 3 ), and an ionic conductivity of 0.018 to 0.032 S / cm (0.028 to 0.031 S / cm).

19. The electrolyte sheet of claim 18, wherein the XRD pattern of the sheet corresponds to the position of the diffraction peaks of the 8YSZ cubic phase structure in the standard card, and substantially does not show diffraction peaks of the non-cubic phase.

20. A solid oxide battery comprising an electrolyte sheet as an electrode as described in claim 18 or 19.

Images