Compact ceramic thin film based on phase transfer method, preparation method of compact ceramic thin film and battery

Abstract

The invention discloses a compact ceramic film based on a phase transfer method, a preparation method of the compact ceramic film and a battery, and the preparation method of the compact ceramic film based on the phase transfer method comprises the following steps: preparing ceramic slurry which comprises ceramic powder, an organic polymer and an organic solvent; the ceramic slurry is subjected to tape casting to a preset thickness and then sequentially subjected to pre-drying, non-solvent spray curing, drying and sintering, and the compact ceramic thin film based on the phase transfer method is obtained. The preparation method of the compact ceramic thin film based on the phase transfer method provided by the invention replaces a traditional process of firstly coating a substrate and then immersing in a coagulating bath, and through precise control of pre-drying and non-solvent spraying, the defects of wrinkles and finger-shaped holes in the ceramic thin film are effectively avoided, and the compactness of the ceramic thin film is improved; therefore, the ionic conductivity and the heat transfer efficiency of the ceramic film are greatly reduced. In addition, the preparation method of the ceramic thin film is high in preparation efficiency and low in production cost.

Description

Technical Field

[0001] The invention relates to the field of batteries, and in particular to a dense ceramic film based on a phase transfer method, a preparation method thereof, and a battery. Background Art

[0002] Traditional ceramic films are prepared by the cast film method. The process of preparing ceramic films by the cast film method is very sensitive to the environmental atmosphere, temperature and humidity. The formula often contains volatile organic solvents, which require long-term slow drying to avoid cracking. At the same time, the volatile atmosphere will also cause pollution and harm the health of workers. The phase transfer method can achieve the preparation of thin films with simple processes, without excessive consideration of the influence of temperature and humidity. The equipment is simple and the molding can be done instantly. It can greatly improve the production efficiency and has no volatile pollutants. However, the film formed by the phase transfer method usually contains obvious macroporous structures, which has a great influence on the uniformity of the film. At the same time, in the traditional phase transfer film forming process, fiber (such as non-woven fabric) substrate materials are needed to fix the film to prevent wrinkles caused by film shrinkage during the phase transfer film forming process. However, the substrate material has the problem that it cannot be separated from the film after film formation.

[0003] Therefore, when ceramic films are used in solid oxide fuel cells, solid-state batteries and other fields, it is necessary to find a phase transfer molding preparation method that can form high density, separate the substrate material and avoid shrinkage and wrinkling of the film. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a dense ceramic film based on the phase transfer method, a preparation method thereof, and a battery, aiming to solve the problems that the current ceramic films prepared by the phase transfer method have low density, large pores in the internal structure, and require the use of fiber substrate materials.

[0005] To achieve the above-mentioned purpose, the present invention proposes a method for preparing a dense ceramic film based on a phase transfer method, comprising the following steps: preparing a ceramic slurry, wherein the ceramic slurry comprises a ceramic powder, an organic polymer and an organic solvent; casting the ceramic slurry into a preset thickness and pre-drying it in an oven to obtain an intermediate product; allowing the intermediate product to contact with a non-solvent spray for solidification, and sintering after drying to obtain a dense ceramic film based on the phase transfer method.

[0006] Optionally, the D50 of the ceramic powder is 0.1 um to 1.5 um, and the slurry includes 40wt% to 80wt% of ceramic powder particles, 20wt% to 50wt% of an organic solvent, and 12wt% to 30wt% of a polymer.

[0007] Optionally, the preset thickness is 10um ~ 500um.

[0008] Optionally, the organic polymer includes at least one of polysulfone, polyethersulfone, polyphenylsulfone, ethylene vinyl alcohol, cellulose acetate, polyacrylonitrile, cellulose, polyvinylidene fluoride, polyimide, polyamide, and polyvinyl pyrrolidone.

[0009] Optionally, the organic solvent includes N-methyl-2-pyrrolidone, acetone, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, dimethylacetamide, formylpiperidine, dioxane, acetic acid, and morpholine.

[0010] Optionally, the non-solvent vapor includes at least one of water, a water-NMP mixture, a water-DMAC mixture, a water-DMSO mixture, ethanol, isopropanol, and ethylene glycol.

[0011] Optionally, the oven pre-drying temperature is 50° C. to 250° C.; and / or the oven pre-drying time is 0.5 min to 5 min.

[0012] In order to achieve the above object, the present invention also provides a dense ceramic film prepared by the above method.

[0013] In order to achieve the above objectives, the present invention also proposes a battery, comprising the above-mentioned dense ceramic film based on the phase transfer method, wherein the battery is selected from any one of a solid oxide fuel cell, a solid oxide electrolysis cell, a solid-state lithium ion battery, and a sodium ion battery.

[0014] Beneficial effects of the present invention: The method for preparing a dense ceramic film based on the phase transfer method provided by the present invention adopts a process of pre-drying combined with non-solvent spray curing to replace the traditional process of combining substrate coating with immersion in a coagulation bath, thereby simplifying the production process and reducing the complexity of the equipment, and avoiding the use of substrate materials. Precise control of pre-drying and non-solvent spraying effectively avoids wrinkles and finger-like hole defects caused by shrinkage during film immersion, avoids insufficient density of the film, reduces the ionic conductivity of the film, the heat transfer efficiency of the film, and the uneven stress and thermal stress of the film, thereby avoiding cracking and breakage of the ceramic film. Ultimately, the ceramic film preparation method of the present invention can significantly improve preparation efficiency and production capacity and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1The manufacturing equipment of the embodiment of the present invention, 01 is a film tape unwinding device, 02 is a water platform, 03 is a casting mechanism, 04 is a slurry, 05 is an adsorption mechanism, 06 is a pre-drying oven, 07-1, 07-2, 07-3 are atomizers, 08 is a water recovery mechanism, 09 is a drying mechanism, and 10 is a film recovery mechanism; Figure 2 This is a scanning electron microscope characterization image of the ceramic film of Example 1 of the present invention; Figure 3 This is a scanning electron microscope characterization image of the ceramic film of Example 2 of the present invention; Figure 4 This is a scanning electron microscope characterization image of the ceramic film of Comparative Example 1 of the present invention; Figure 5 This is a scanning electron microscope characterization image of the ceramic film of Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0018] Unless defined otherwise, all technical and scientific terms used herein have the common meaning in the art to which the claimed subject matter pertains.

[0019] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0020] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if the meaning of "and / or" appearing in the full text is to include three parallel schemes, taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0021] When ceramic films are prepared by the phase transfer method, it is usually to achieve a porous structure of "finger-like holes" formed inside the porous ceramics by the phase transfer method during the film preparation process. Such a porous structure is conducive to mass transfer and is convenient for loading catalysts, electrodes and other functional layers in subsequent applications. The advantages of the phase transfer method for preparing ceramic films include easy and fast film formation and good uniformity, which avoids problems such as uneven film formation caused by solvent volatilization and environmental sensitivity of film forming conditions. In addition, in the process of preparing films by the traditional phase transfer method, a non-solvent bath is often used to solidify the slurry layer into a film. During this process, the slurry layer will shrink and cause film wrinkles. The use of atomization can reduce the solidification rate of the film during the phase transfer process, which can avoid the problem of film shrinkage and wrinkles. At the same time, in the traditional phase transfer casting process, a non-woven fabric substrate material is needed to fix the film, but in subsequent applications, the film is usually used in combination with the substrate fiber material, and it is impossible to separate them completely.

[0022] Therefore, the application of ceramic films in solid oxide fuel cells, solid-state batteries and other fields requires finding an efficient preparation method that has high density, does not cause wrinkles in the membrane and does not rely on fiber substrates.

[0023] In order to solve the above problems, the present invention proposes a method for preparing a dense ceramic film based on a phase transfer method, comprising the following steps: S1: preparing a ceramic slurry, wherein the ceramic slurry comprises a ceramic powder, an organic polymer and an organic solvent; In this scheme, the ceramic powder is preferably granulated powder, and the granulation methods include spray granulation, dry pressing granulation, cold isostatic pressing granulation, freeze drying, etc. The granulated ceramic powder is obtained by strictly controlling the production process of the powder, and the powder quality is stable and reliable, the particle distribution is uniform, and the sintering range is wide, which is conducive to adapting to the process and achieving a better phase transfer effect.

[0024] In some embodiments, the ceramic powder is Zr 0.92 Y 0.08 O 2 Powder.

[0025] In some embodiments, the step of preparing the ceramic slurry includes mixing ceramic powder, organic polymer and organic solvent and then dispersing by ball milling to obtain a uniform ceramic slurry.

[0026] S2: Casting the ceramic slurry into a preset thickness and pre-drying it in an oven to obtain an intermediate product; S3: The intermediate product is allowed to contact with a non-solvent spray for solidification, and then sintered after drying to obtain a dense ceramic film based on a phase transfer method.

[0027] In this scheme, the slurry is scraped to the desired thickness using a casting scraper, such as Figure 1As shown, while the slurry of required thickness is scraped out by casting, the slurry film belt is in continuous movement and is sprayed with a non-solvent. There can be multiple non-solvent sprays, so that the spray contacts the surface of the slurry film until the slurry is completely solidified into a film.

[0028] This solution adopts the process of "pre-drying combined with non-solvent spray curing" to replace the traditional "substrate coating + immersion coagulation bath" process, which simplifies the production process, reduces the complexity of equipment, and avoids the use of substrate materials. The precise control of pre-drying + non-solvent spray effectively avoids wrinkles and finger-like pore defects caused by shrinkage during film immersion, so that the porous structure inside the ceramic film presents a uniform sponge-like pore structure. After sintering, the density is increased to a porosity of <0.1%, and the ionic conductivity reaches 0.15 S / cm (600°C), avoiding the film's insufficient density, reducing the film's ionic conductivity, the film's heat transfer efficiency, and the film's stress and thermal stress unevenness, thereby avoiding the cracking and breakage of the ceramic film. Finally, the ceramic film preparation method of the present invention can significantly improve preparation efficiency and production capacity and reduce costs.

[0029] In some embodiments, drying includes: after the slurry is completely cured, taking out the formed film, pressing the film with a breathable ceramic substrate, and placing it in an oven at 120° C. to dry for 2 hours.

[0030] In some embodiments, the control of the sintering temperature includes: firstly, heating the high temperature furnace to the debinding temperature at a heating rate of 2°C per minute. The preferred debinding temperature may be 430°C to 500°C, and most preferably, the debinding temperature is 440°C to 470°C. The holding time at the debinding temperature is preferably 10 to 15 hours, and the temperature is raised to 1000°C at 2°C per minute, and then the temperature is raised to the sintering temperature at 0.5°C per minute and kept at that temperature for 5 hours. After cooling to 600°C at 2°C per minute, the high temperature furnace can cool down automatically.

[0031] In some embodiments, the above preparation method is as shown in the attached specification Figure 1 The equipment shown is implemented, 01 is the film tape unwinding device, 02 is the water platform, 03 is the casting mechanism, 04 is the slurry, 05 is the adsorption mechanism, 06 is the pre-drying oven, 07-1, 07-2, 07-3 are atomizers, 08 is the water recovery mechanism, 09 is the drying mechanism, and 10 is the film recovery mechanism. The adsorption mechanism 05 is used to suck the film tape flat so that the casting can be achieved evenly.

[0032] Furthermore, the D50 of the ceramic powder is 0.1 um to 1.5 um, the D90 is 1.5 um to 3 um, and the mass percentage of the ceramic powder in the ceramic slurry is 40% to 80%.

[0033] By optimizing the particle size and solid content of ceramic powder, the fluidity, viscosity and sintering performance of ceramic slurry can be significantly improved. Selecting a suitable dispersant and powder grading is the key to preparing high-performance ceramic slurry. Powders with smaller particle sizes and slurries with high solid content help to improve the density and mechanical properties of the sintered body, but the fluidity and viscosity of the slurry also need to be considered to meet different molding and sintering process requirements. In some embodiments of the present scheme, the mass percentage of ceramic powder in the ceramic slurry is preferably 50% to 70%.

[0034] Furthermore, the preset thickness is 10um to 500um. The thinner the thickness is, the more difficult it is to suppress the growth of finger-shaped holes during the phase transfer process.

[0035] In some embodiments of the present solution, the preset thickness is any value between 20um and 500um, such as 20um, 50um, 100um, 200um, 300um, 400um, 500um, etc. Preferably, the preparation method of the present solution is most effective when the preset thickness is between 50um and 200um.

[0036] Furthermore, the organic polymer includes at least one of polysulfone, polyethersulfone, polyphenylsulfone, ethylene vinyl alcohol, cellulose acetate, polyacrylonitrile, cellulose, polyvinylidene fluoride, polyimide, polyamide, and polyvinyl pyrrolidone.

[0037] Preferably, the organic polymer is polyethersulfone, which has excellent mechanical strength and impact resistance, can enhance the mechanical strength of the ceramic slurry molded body during drying and sintering, and reduce the risk of cracks and fractures. In some embodiments, the mass percentage of polyethersulfone in the ceramic slurry is 5% to 30%, preferably 16% to 25%.

[0038] Furthermore, the organic solvent includes at least one of N-methyl-2-pyrrolidone, acetone, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, dimethylacetamide, formylpiperidine, dioxane, acetic acid, and morpholine.

[0039] The main function of organic solvent is to disperse the powder particles and provide the slurry with suitable viscosity. The rheological properties of the solvent determine the rheological properties of the organic carrier, which in turn affects the process accuracy of the casting.

[0040] Furthermore, the non-solvent includes at least one of water, a water-NMP mixture, a water-DMAC mixture, a water-DMSO mixture, ethanol, isopropanol, and ethylene glycol.

[0041] In this scheme, pre-drying serves to initially solidify the cast slurry. By controlling the rate and time of non-solvent spraying, the solidification rate of the diaphragm can be reduced, the growth of finger-like holes can be prevented, and wrinkles in the film can be prevented due to too fast solidification.

[0042] Furthermore, the oven pre-drying temperature is 50° C. to 250° C.; and / or the oven pre-drying time is 0.5 min to 5 min.

[0043] In order to solve the above problems, the present invention also proposes a dense ceramic film based on a phase transfer method prepared by the above preparation method.

[0044] To solve the above problems, the present invention also proposes a battery, comprising the above-mentioned dense ceramic film based on the phase transfer method, wherein the battery comprises one of a solid oxide fuel cell, a solid oxide electrolysis cell, a solid-state lithium ion battery, and a sodium ion battery.

[0045] In battery applications, the high thermal and chemical stability of dense ceramic films can improve safety and reduce the risk of thermal runaway. Dense ceramic films have high mechanical strength, which can protect the internal structure of the battery from mechanical shock and pressure and extend the service life of the battery. The high thermal conductivity of ceramic materials helps with thermal management of the battery during charging and discharging. In addition, dense ceramic films, as battery separators, reduce the formation of lithium dendrites and improve the cycle stability and life of the battery. The uniform pore size distribution of ceramic separators helps the uniform transmission of ions and reduces the uneven reaction inside the battery. Dense ceramic films can effectively prevent the penetration and leakage of electrolytes, protect the internal structure of the battery, and reduce the volatilization and contamination of electrolytes. The low ion permeability of dense ceramic films can reduce the self-discharge rate of the battery and improve the storage performance and service life of the battery.

[0046] Embodiment 1: Step 1: Select Zr with D50 of 0.75um and D90 of 2um 0.92 Y 0.08 O 2 Ceramic powder, 100g of ceramic powder, 80g of NMP, and 15g of polyethersulfone are ball-milled and mixed to form a uniform slurry; Step 2: The slurry film tape is in continuous movement. A slurry layer with a thickness of 150 μm is scraped on the PET film tape with a casting scraper. The forward speed of the slurry film tape is 0.4 m / min. The film tape passes through a hot oven with a heating temperature of 80°C. The length of the heating zone inside the hot oven is 0.8 m. Step 3: After the film strip comes out of the oven, it is sprayed with water three times, with a spray rate of 3g / s-8g / s and an interval of 30cm between sprays; Step 4, cutting the spray-cured diaphragm and drying it; Step 5: Place the dried film on a corundum substrate, slowly heat it to 450 degrees at a rate of 3 degrees per minute in a high-temperature furnace and keep it warm for 10 hours, then heat it to 1000 degrees at a rate of 2 degrees per minute, then heat it to 1450 degrees at 0.5 degrees Celsius per minute and keep it warm for 5 hours, and finally cool it to 600 degrees at a rate of 2 degrees per minute and then cool it freely.

[0047] Embodiment 2: Step 1: Select Zr with D50 of 0.5um and D90 of 2.5um 0.92 Y 0.08 O 2 Ceramic powder, 100g of ceramic powder, 80g of DMAC, 20g of polysulfone, and 1g of polyvinyl pyrrolidone are ball-milled and mixed to form a uniform slurry; Step 2: The slurry film tape is in continuous movement. A slurry layer with a thickness of 200um is scraped on the PET film tape with a casting scraper. The slurry film tape moves at a speed of 0.4m / min. The film tape passes through a hot oven with a heating temperature of 60°C. The length of the heating zone inside the hot oven is 0.3m. Step 3: After the film strip comes out of the oven, it is sprayed with a water-NMP mixed solution three times. The concentration of NMP is 60 wt%, the spray rate is 3 g / s-8 g / s, and the interval between sprays is 30 cm. Step 4, cutting the spray-cured diaphragm and drying it; Step 5: Place the dried film on a corundum substrate, slowly heat it to 450 degrees at a rate of 3 degrees per minute in a high-temperature furnace and keep it warm for 10 hours, then heat it to 1000 degrees at a rate of 2 degrees per minute, then heat it to 1450 degrees at 0.5 degrees Celsius per minute and keep it warm for 5 hours, and finally cool it to 600 degrees at a rate of 2 degrees per minute and then cool it freely.

[0048] Comparative Example 1: Step 1: Select Zr with D50 of 0.75um and D90 of 2um 0.92 Y 0.08 O 2 Ceramic powder, 100g of ceramic powder, 80g of NMP, and 15g of polyethersulfone are ball-milled and mixed to form a uniform slurry; Step 2: While scraping out the required thickness of slurry by casting, the slurry film belt is in continuous movement, and a slurry layer with a thickness of 150um is scraped out on the polyethylene film belt with a casting scraper. The forward speed of the slurry film belt is 0.4m / min. The film belt is sprayed with water three times, the spray amount is 3g / s-8 g / s, and the interval between sprays is 30cm; Step 4, cutting the spray-cured diaphragm and drying it; Step 5: Place the dried film on a corundum substrate, slowly heat it to 450 degrees at a rate of 3 degrees per minute in a high-temperature furnace and keep it warm for 10 hours, then heat it to 1000 degrees at a rate of 2 degrees per minute, then heat it to 1450 degrees at 0.5 degrees Celsius per minute and keep it warm for 5 hours, and finally cool it to 600 degrees at a rate of 2 degrees per minute and then cool it freely.

[0049] Comparative Example 2: Step 1: Select Zr with D50 of 0.75um and D90 of 2um 0.92 Y 0.08 O 2 Ceramic powder, 100g of ceramic powder, 80g of NMP, and 15g of polyethersulfone are ball-milled and mixed to form a uniform slurry; Step 2: The slurry film tape is in continuous movement. A slurry layer with a thickness of 150 μm is scraped on the PET film tape with a casting scraper. The forward speed of the slurry film tape is 0.4 m / min. The film tape passes through a hot oven with a heating temperature of 80°C. The length of the heating zone inside the hot oven is 0.8 m. Step 3: directly immerse the pre-cured slurry after heat drying into water for curing; Step 4: Cut the solidified diaphragm and dry it; Step 5: Place the dried film on a corundum substrate, slowly heat it to 450 degrees at a rate of 3 degrees per minute in a high-temperature furnace and keep it warm for 10 hours, then heat it to 1000 degrees at a rate of 2 degrees per minute, then heat it to 1450 degrees at 0.5 degrees per minute and keep it warm for 5 hours, and finally cool it to 600 degrees at a rate of 2 degrees per minute and then cool it freely.

[0050] Furthermore, the dense ceramic film finally prepared in Example 1-2 is used in a battery, and the sintered Zr 0.92 Y 0.08 O 2 The film is placed on a screen printer, and the prepared solid oxide anode slurry is screen printed on the surface of the ceramic film. This process can be repeated to achieve the required thickness. The anode slurry preparation process is as follows: 100g of pine alcohol, 110g of nickel oxide powder (D50 0.8 um), Ce 0.9 G 0.1 O 2 75g of powder (D50 0.5 um) and 1.85g of ethyl cellulose were mixed evenly by ball milling and then degassed by vacuum stirring. After screen printing, the ceramic sheet was placed in an oven at 150 degrees to dry. The dried ceramic sheet was sintered at high temperature, heating up to 1000 degrees at 2 degrees per minute, heating up to 1350 degrees at 1 degree per minute and keeping the temperature for 5 hours, and finally cooling down to 600 degrees at 2 degrees per minute and then cooling freely.

[0051] Place the anode sintered ceramic sheet on a screen printer and use the prepared solid oxide cathode slurry to screen print on the surface of the ceramic film. This can be repeated multiple times to achieve the required thickness. The cathode slurry preparation process is as follows: 100g pine alcohol, La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 Powder (D50 0.8 um) 110g, Ce 0.9 G 0.1 O 2 75g of powder (D50 0.5 um) and 1.85g of ethyl cellulose were mixed evenly by ball milling and then degassed by vacuum stirring. After screen printing, the ceramic sheet was placed in a 150-degree oven for drying. The dried ceramic sheet was sintered at high temperature, heated to 1000 degrees at 2 degrees per minute and kept warm for 5 hours, and finally cooled to 600 degrees at 2 degrees per minute and then cooled freely. Performance tests were carried out, and the results are shown in Table 1 below: Table 1.

[0052] It should be noted that Figure 2 , Figure 3 , Figure 4 and Figure 5 These are scanning electron microscope images of the ceramic films prepared in Example 1, Example 2, Comparative Example 1 and Comparative Example 2, respectively, with the same shooting parameters, specifically including: image scale of 50 μm; acceleration voltage of 10 kV; detector type of in-scope detector; working distance of 8.0 mm; and magnification of 200 times.

[0053] refer to Figure 2 , the film (unsintered) made in Example 1 has uniform sponge-like pores in cross section; Figure 3 , the membrane prepared in Example 2 (unsintered) has a reduced pre-drying time, but the spraying uses a solution with a high NMP concentration, which can also help eliminate the finger-like pores and achieve a uniform sponge-like pore structure; reference Figure 4 , Comparative Example 1 is a film that has not been pre-dried (unsintered), and a large number of finger-like holes are generated inside; Figure 5 ,Comparative Example 2 (unsintered membrane), the pre-dried membrane was directly immersed in water without non-solvent spraying, and wrinkles appeared on the membrane surface and finger-like holes appeared inside.

[0054] According to this form and Figure 2 , Figure 3 , Figure 4 and Figure 5The characterization results can confirm that the preparation method of dense ceramic film based on phase transfer method provided by this scheme adopts the process of "pre-drying combined with non-solvent spray curing" to replace the traditional "substrate coating + immersion solidification bath" process, which simplifies the production process and reduces the complexity of equipment, and avoids the use of substrate materials. The precise control of pre-drying + non-solvent spray effectively avoids wrinkles and finger-like pore defects caused by shrinkage during film immersion, and increases the density of the ceramic film to a porosity of <0.1%, the ionic conductivity reaches 0.15 S / cm (600°C), and the mechanical strength is increased to 280 MPa, avoiding the film's insufficient density, reducing the film's ionic conductivity, the film's heat transfer efficiency, and the film's stress and thermal stress unevenness, thereby avoiding the cracking and breakage of the ceramic film. Finally, the ceramic film preparation method of the present invention can significantly improve preparation efficiency, production capacity, and reduce costs.

[0055] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A method for preparing a dense ceramic film based on a phase transfer method, characterized in that: The following steps are involved: preparing a ceramic slurry, wherein the ceramic slurry comprises ceramic powder, an organic polymer and an organic solvent; After the ceramic slurry is cast into a preset thickness, it is first pre-dried in an oven, then contacted with a non-solvent spray for solidification, and then sintered after drying to obtain a dense ceramic film based on a phase transfer method.

2. The method for preparing a dense ceramic film based on a phase transfer method according to claim 1, characterized in that: The D50 of the ceramic powder is 0.1 um to 1.5 um, and the slurry includes 40 wt % to 80 wt % of ceramic powder particles, 20 wt % to 55 wt % of an organic solvent, and 12 wt % to 30 wt % of an organic polymer.

3. The method for preparing a dense ceramic film based on a phase transfer method according to claim 1, characterized in that: The preset thickness is 10um~500um.

4. The method for preparing a dense ceramic film based on a phase transfer method according to claim 1, characterized in that: The organic polymer includes at least one of polysulfone, polyethersulfone, polyphenylsulfone, ethylene vinyl alcohol, cellulose acetate, polyacrylonitrile, cellulose, polyvinylidene fluoride, polyimide, polyamide, and polyvinyl pyrrolidone.

5. The method for preparing a dense ceramic film based on a phase transfer method according to claim 1, characterized in that: The organic solvent includes at least one of N-methyl-2-pyrrolidone, acetone, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, dimethylacetamide, formylpiperidine, dioxane, acetic acid, and morpholine.

6. The method for preparing a dense ceramic film based on a phase transfer method according to claim 1, characterized in that: The non-solvent spray includes at least one of water, a water-NMP mixture, a water-DMAC mixture, a water-DMSO mixture, ethanol, isopropanol, and ethylene glycol.

7. The method for preparing a dense ceramic film based on a phase transfer method according to claim 1, characterized in that: The pre-drying temperature of the oven is 50°C to 250°C; And / or, the pre-drying time in the oven is 0.5 min to 5 min.

8. A dense ceramic film, characterized in that: The method is prepared by the method according to any one of claims 1 to 7.

9. A battery, characterized in that: A dense ceramic film comprising the dense ceramic film of claim 8; The battery is selected from any one of a solid oxide fuel cell, a solid oxide electrolysis cell, a solid-state lithium ion battery, and a sodium ion battery.

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