An oxide solid electrolyte thin film and a preparation method, and a solid-state battery

Abstract

This invention relates to an oxide solid electrolyte film and its preparation method, as well as a solid-state battery. The film comprises multiple independent solid electrolyte units and at least one polymer. The polymer connects the multiple independent solid electrolyte units to form a large-area oxide solid electrolyte film, and the thickness of the polymer is less than the thickness of the solid electrolyte units. This invention achieves this by covering the surface of the solid electrolyte green ceramic tape with a support layer and a burn-off layer, and by tightly pressing multiple flexible solid electrolyte green ceramic tapes into a stack with a certain structural strength. This ensures uniform burn-off gaps between adjacent green ceramic tape stacks, prevents warping and deformation of the solid electrolyte green ceramic tapes during sintering, and ensures uniform distribution of the solid electrolyte in the final solid electrolyte film.

Description

Technical Field

[0001] This invention relates to the technical field of solid-state batteries, and in particular to an oxide solid electrolyte thin film, its preparation method, and a solid-state battery. Background Technology

[0002] In the fabrication process of solid-state batteries, the current main method for preparing oxide solid electrolyte films is to mix oxide solid electrolyte particles with a binder similar to polyvinylidene fluoride, and then form a solid electrolyte film through casting or pressing processes.

[0003] Patent application number 202510211608.7 discloses an oxide solid electrolyte film and its preparation method, as well as a solid battery. The method first prepares a rigid solid electrolyte sheet through a ceramic sintering process. Then, the solid electrolyte sheets are stacked and a polymer is added to prepare a composite solid electrolyte body. Finally, the composite solid electrolyte body is cut by multi-wire cutting to obtain a flexible solid electrolyte film.

[0004] However, when preparing solid electrolyte sheets using ceramic forming processes, the sheets are very thin and often warp slightly during high-temperature sintering. This results in uneven distribution of the solid electrolyte in the stacked sheets, leading to a problem of uneven solid electrolyte distribution in the final oxide solid electrolyte film. Furthermore, to avoid the defects caused by warping, a thicker polymer bonding layer is required, which reduces the contact area between the solid electrolyte and the positive and negative electrodes of the battery, thus affecting the ionic conductivity of the oxide solid electrolyte film. Summary of the Invention

[0005] To improve the uniformity of solid electrolyte in solid electrolyte films, the present invention aims to provide an oxide solid electrolyte film, its preparation method, and a solid battery.

[0006] The primary objective of this application is to provide a method for preparing an oxide solid electrolyte thin film, comprising the following steps: S1. Flexible solid electrolyte green ceramic tape is prepared by ceramic forming process; S2. Lay and cover a support layer and a burn-off layer on the surface of the solid electrolyte green ceramic tape; S3. Stack multiple solid electrolyte green ceramic tapes in their own thickness direction to obtain a green ceramic tape stacked structure. S4. Press the stacked green ceramic strips together to form a stacked green ceramic strip body; S5. Sintering green ceramic belt stacks, causing the burn-off layer to oxidize at high temperature to form burn-off voids, thus preparing a solid electrolyte with uniform burn-off voids; S6. Combine the polymer with the solid electrolyte to prepare a solid electrolyte composite. S7. Shape the solid electrolyte complex. S8. Perform multi-wire cutting on the solid electrolyte complex to obtain a solid electrolyte membrane; S9. The polymer in the solid electrolyte membrane is thinned to obtain an oxide solid electrolyte film with a polymer thickness smaller than the thickness of the solid electrolyte unit.

[0007] By adopting the above technical solution, by setting a support layer and a burn-off layer on the surface of the flexible solid electrolyte green ceramic tape, the flexible solid electrolyte green ceramic tape can be uniformly and stably supported during the stacking process, and further pressed to form a green ceramic tape stack, ensuring that each solid electrolyte green ceramic tape is on the same horizontal plane, so that the solid electrolyte body has uniform burn-off voids, thereby ensuring that the solid electrolyte units are uniformly distributed in the prepared solid electrolyte film.

[0008] The present invention is further configured such that, in S2, the support layer is prepared by screen printing, the burn-off layer is prepared by screen printing, or it is prepared by setting a burn-off layer film in a region other than the support layer.

[0009] By adopting the above technical solution, the support layer and the ignition loss layer are set on the surface of the solid electrolyte green ceramic tape through screen printing process, which can ensure that the thickness of the support layer and the ignition loss layer is uniformly distributed, thereby ensuring that the solid electrolyte green ceramic tape has a uniform spacing after stacking, and effectively avoiding warping of the solid electrolyte green ceramic tape during sintering.

[0010] The present invention is further configured such that: in S4, the green ceramic tape stack structure is pressed together by a laminator or a warm isostatic press to form a green ceramic tape stack body.

[0011] By adopting the above technical solution, after pressing the green ceramic tape stacked structure with a laminator or a warm isostatic press, the green ceramic tape stacked structure can be tightly combined to form a green ceramic tape stack with a certain structural strength, thus avoiding warping and deformation of the solid electrolyte green ceramic tape during the sintering process.

[0012] The present invention is further configured such that, in step S6, the following sub-steps are included: S6-11. Fill the burn-off voids of the solid electrolyte body with a high molecular polymer to form a solid electrolyte complex. S6-12. Select the side of the solid electrolyte body with burn-off voids, and make multi-line cuts on the solid electrolyte body along the direction perpendicular to the burn-off voids to form multi-line cut slits. S6-13. Clean the solid electrolyte complex after multi-wire cutting and dry it completely; S6-14. A solid electrolyte composite is prepared by filling the gaps in a multi-line cut with a polymer. By adopting the above technical solution, the polymer can be filled multiple times, thereby improving the bonding effect between the polymer and the solid electrolyte.

[0013] The present invention is further configured such that, in step S6, the following sub-steps are included: S6-21. Select the side of the solid electrolyte body with burn-off voids and perform multi-line cutting on the solid electrolyte body along the direction perpendicular to the burn-off voids. S6-22. Clean the solid electrolyte body after multi-wire cutting and dry it completely; S6-23. A solid electrolyte composite is prepared by filling the burn-off voids and cut gaps of the solid electrolyte body with a polymer.

[0014] By adopting the above technical solution, since the solid electrolyte has high strength, the preparation efficiency of the solid electrolyte composite can be improved by multi-wire cutting of the solid electrolyte and setting the polymer. This avoids the need for multiple polymer setting steps.

[0015] The present invention is further configured such that, in S6, the polymer fills the burn-off voids of the solid electrolyte.

[0016] By adopting the above technical solutions, the loss of solid electrolyte materials during processing can be reduced, and the content of solid electrolyte in oxide solid electrolyte films can be increased.

[0017] The present invention is further configured such that, in S9, the thinning process of the polymer includes one or more of chemical etching, physical etching, ion beam etching, and thermal thinning.

[0018] By adopting the above technical solution, the polymer is thinned so that the thickness of the polymer is less than the thickness of the solid electrolyte unit, so that the solid electrolyte unit on the oxide solid electrolyte film has a raised 3D structure, thereby increasing the contact area between the oxide solid electrolyte and the electrode material.

[0019] The second objective of this application is to provide an oxide solid electrolyte film, prepared using the aforementioned method, comprising multiple independent solid electrolyte units and at least one polymer. The polymer is bonded to the multiple independent solid electrolyte units to form the oxide solid electrolyte film. The thickness of the polymer is less than the thickness of the solid electrolyte units. The thickness of a single solid electrolyte unit is 10-2000 μm, and the surface area of ​​a single solid electrolyte unit exposed to the outside is 0.01-300 mm². 2.

[0020] By adopting the above technical solution, since the thickness of the polymer is less than the thickness of the solid electrolyte unit, the solid electrolyte unit on the oxide solid electrolyte film will have a raised 3D structure, which increases the surface of the solid electrolyte unit exposed to the outside world, thereby expanding the contact area between the solid electrolyte and the electrode material and improving the ion conduction effect.

[0021] The present invention is further configured such that the polymer contains a modified material that increases ionic conductivity.

[0022] By adopting the above technical solution, the ionic conductivity of polymers is enhanced by introducing modifying materials that increase ionic conductivity into the molecular structure of polymers.

[0023] The third objective of this application is to provide a solid-state battery, including an oxide solid-state electrolyte film prepared by the above-described method for preparing an oxide solid-state electrolyte film. The solid-state battery also includes a positive electrode and a negative electrode, wherein the oxide solid-state electrolyte film is disposed between the positive electrode and the negative electrode as a channel for ion transfer.

[0024] By adopting the above technical solution, since the solid electrolyte unit on the oxide solid electrolyte film has a raised 3D structure, the solid electrolyte film and the positive and negative electrodes can have a large contact area, thereby improving the ion transfer effect.

[0025] In summary, the beneficial technical effects of the present invention are as follows: 1. By covering the surface of the solid electrolyte green ceramic tape with a support layer and a burn-off layer, and tightly pressing multiple flexible solid electrolyte green ceramic tapes into a green ceramic tape stack with a certain structural strength, it is ensured that there is a uniform burn-off gap between adjacent green ceramic tape stacks, preventing the solid electrolyte green ceramic tape from warping and deforming during the sintering process, and ensuring that the solid electrolyte can be uniformly distributed in the final solid electrolyte film. 2. By processing the flexible solid electrolyte green ceramic tape, the solid electrolyte green ceramic tape will not crack due to pressure during stacking or pressing, thereby improving the preparation efficiency of solid electrolyte and optimizing the product quality of solid electrolyte film. 3. The solid electrolyte cells on the oxide solid electrolyte film have a raised 3D structure. When used in solid-state batteries, the raised parts of the solid electrolyte cells are interlocked with the positive or negative electrode materials, so that the solid electrolyte film has a large contact area with the positive and negative electrodes, which enhances the ion transfer effect and thus improves the ionic conductivity of the solid-state battery. Attached Figure Description

[0026] Figure 1This is a schematic diagram of the structure of the oxide solid electrolyte film in the embodiments of this application.

[0027] Figure 2 This is a side view of the oxide solid electrolyte film in the embodiments of this application.

[0028] Figure 3 This is a top view of the solid electrolyte green ceramic tape in an embodiment of this application.

[0029] Figure 4 This is a side view of the stack of green ceramic tapes in an embodiment of this application.

[0030] Figure 5 This is a side view of the solid electrolyte in an embodiment of this application.

[0031] Figure 6 This is a schematic diagram of the structure of the solid electrolyte in the embodiments of this application.

[0032] Figure 7 This is a side view of the solid electrolyte complex in Embodiments 2 and 3 of this application.

[0033] Figure 8 This is a schematic diagram of the structure of the oxide solid electrolyte film in Embodiment 2 of this application.

[0034] Figure 9 This is a schematic diagram of the structure of the oxide solid electrolyte film in Embodiment 3 of this application.

[0035] Figure 10 This is a schematic diagram of the structure of the oxide solid electrolyte film in Embodiment 4 of this application.

[0036] In the figure, 1 is the solid electrolyte unit, 2 is the polymer, 3 is the solid electrolyte green ceramic tape, 4 is the support layer, 5 is the burn-off layer, 6 is the green ceramic tape stack, 7 is the solid electrolyte body, and 8 is the solid electrolyte composite. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings.

[0038] This application discloses an oxide solid electrolyte thin film, its preparation method, and a solid battery.

[0039] Example 1: Refer to Figure 1 and Figure 2 The present invention discloses an oxide solid electrolyte film comprising a plurality of independent solid electrolyte units 1 and at least one polymer 2, wherein the polymer 2 is combined with the plurality of independent solid electrolyte units 1 to form a large-area oxide solid electrolyte film.

[0040] The independent solid electrolyte units 1 can be of various shapes or have a certain nesting arrangement. In order to make the oxide solid electrolyte film have a certain degree of flexibility in order to solve the problems of poor solid-solid contact interface and interface contact deterioration after cycle durability, a certain degree of flexible polymer 2 is set between the independent solid electrolyte units 1, thereby making the entire film flexible.

[0041] When a solid electrolyte film is used, the thinner it is, the faster ions can penetrate, thus achieving better charge and discharge performance. At the same time, the larger the contact area between the solid electrolyte and the positive and negative electrodes, the more conducive it is to ion transport. In this embodiment, the thickness of the polymer 2 is set to be smaller than the thickness of the solid electrolyte unit 1, so that the oxide solid electrolyte film has a larger expansion space.

[0042] In the specific implementation process, the thickness of a single solid electrolyte unit 1 is 10-2000 μm, which increases the thickness range of the solid electrolyte unit 1 and correspondingly increases the strength of the single solid electrolyte unit 1, thereby increasing the surface area of ​​the solid electrolyte unit 1 exposed to the outside world, where the surface area of ​​a single solid electrolyte unit 1 exposed to the outside world reaches 0.01-300 mm. 2 Since the thickness of the polymer 2 is less than the thickness of the solid electrolyte unit 1, the solid electrolyte unit 1 on the oxide solid electrolyte film will have a raised 3D structure, which will give the solid electrolyte unit 1 a larger surface area. At the same time, it will reduce the adverse effects of the increase in the thickness of the solid electrolyte unit 1. Furthermore, the solid electrolyte unit 1 can be intercalated with the positive or negative electrode material of the solid battery to increase the contact area between the oxide solid electrolyte film and the positive and negative electrodes, thereby enhancing the ionic conductivity.

[0043] The electrolyte material of the solid electrolyte unit 1 can be selected according to the usage environment. It can be one or more of the following types: garnet, perovskite, anti-perovskite, LISICON, NASICON, apatite, and spinel. If used in a lithium-ion solid battery, an electrolyte material with lithium-ion conductivity is selected. If used in a sodium-ion solid battery, an electrolyte material with sodium-ion conductivity is selected. In the specific implementation, LISICON type lithium zirconium silicon phosphate is selected as the solid electrolyte. This electrolyte material has the advantages of high ionic conductivity, a wide electrochemical window, and strong compatibility with positive and negative electrode materials.

[0044] The selection of polymer 2 needs to meet the requirement of having good bonding strength with the solid electrolyte or improving the bonding strength through self-modification or interface modification. One or more of the following are selected: polyethylene oxide, polyacrylonitrile, polyimide, polyvinylidene fluoride, polyether ether ketone, polyphenylene sulfide, polyethersulfone, polyamide imide, polyurethane, acrylate polymers, epoxy resin and rubber. In the specific implementation process, polyimide is selected as the main material. This material has good bonding force with lithium silicon zirconium phosphate solid electrolyte and can work for a long time in an environment above 300°C, which greatly broadens the working temperature range of the oxide solid electrolyte film.

[0045] The polymer 2 contains a modified material to improve its ionic conductivity. By introducing one or more of succinic acid, lithium-containing groups, lithium salts, and nanofillers into the molecular structure of the polymer 2, the polymer 2 is made ionicly conductive, thereby further improving the ionic conductivity of the oxide solid electrolyte film.

[0046] Example 2: Refer to Figures 3-7 The present invention discloses a method for preparing an oxide solid electrolyte thin film, comprising the following steps: S1. A flexible solid electrolyte green ceramic belt 3 was prepared by a ceramic forming process; S2. A support layer 4 and a burn-off layer 5 are laid and covered on the surface of the solid electrolyte green ceramic belt 3; S3. Stack multiple solid electrolyte green ceramic strips 3 in their own thickness direction to obtain a green ceramic strip stacked structure. S4. Press the stacked green ceramic tapes together to form a stacked green ceramic tape body 6; S5, sintered green ceramic belt stack 6, so that the burn-off layer 5 is oxidized at high temperature to form burn-off voids, and a solid electrolyte body 7 with uniform burn-off voids is prepared. S6. Combine the polymer 2 with the solid electrolyte 7 to prepare the solid electrolyte composite 8. S7. The solid electrolyte complex 8 is modified so that the polymer 2 is wrapped around the outside of the solid electrolyte. S8. Perform multi-wire cutting on the solid electrolyte composite 8 to obtain a solid electrolyte membrane with a thickness of 10-2000 μm. S9. The polymer 2 in the solid electrolyte membrane is thinned to obtain an oxide solid electrolyte film with a polymer 2 thickness less than the thickness of the solid electrolyte unit 1.

[0047] In the specific implementation of S1, lithium silicon zirconium phosphate is selected as the solid electrolyte, polyvinyl butyral is selected as the binder, dibutyl phthalate is selected as the plasticizer, modified fish oil is selected as the dispersant, and a mixture of ethanol and butanone is selected as the solvent to prepare an electrolyte slurry. The electrolyte slurry is cast into a film with a thickness of 0.1-2 mm by a casting process. Then, the cast film is punched to obtain a flexible solid electrolyte green ceramic tape 3 of uniform size. In this embodiment, the prepared solid electrolyte green ceramic tape 3 is a rectangular flexible sheet with a thickness of 0.5 mm and a length and width of 200*120 mm.

[0048] In the specific implementation of S2, when setting the support layer 4, first select one surface of the solid electrolyte green ceramic belt 3, and print lithium silicon zirconium phosphate paste on the edge of the long side of the solid electrolyte green ceramic belt 3 through screen printing process to form two parallel support layers 4.

[0049] In another embodiment, lithium silicon zirconium phosphate paste is printed onto the edge portions of three sides of the solid electrolyte green ceramic strip 3 using a screen printing process, forming a U-shaped support layer 4.

[0050] The support layer 4 can be a continuous or discontinuous strip structure. In the specific implementation process, the support layer 4 is set as a continuous strip structure to improve the bonding effect of the green ceramic tape stacked structure during the pressing process.

[0051] When setting the burn-off layer 5, spherical graphite is selected as the main material of the burn-off layer 5, modified fish oil is selected as the dispersant, terpineol is selected as the solvent, and dibutyl phthalate is selected as the plasticizer. After high-energy ball milling, a burn-off layer slurry with good rheological properties is prepared. The burn-off layer slurry is printed on the area outside the support layer 4 by screen printing process, so that the support layer 4 and the burn-off layer 5 together cover the surface of the solid electrolyte green ceramic belt 3. The thickness of the support layer 4 and the burn-off layer 5 is set to 0.15mm. After pressing the stacked structure of green ceramic belts, warping of the solid electrolyte green ceramic belt 3 can be prevented, and the adjacent electrolyte green ceramic belts have the same spacing at different positions.

[0052] When the S5 sintering green ceramic belt stack 6 is carried out, the burn-off layer 5 will gradually oxidize and burn off under high temperature, and burn-off voids will be formed in the original burn-off layer 5 area.

[0053] In the specific implementation of S3, multiple solid electrolyte green ceramic strips 3 are stacked in their own thickness direction to obtain a green ceramic strip stack structure. The green ceramic strip stack structure is placed in a pressing fixture to prevent the solid electrolyte green ceramic strips 3 from shifting during the pressing process.

[0054] In the specific implementation of S4, the green ceramic tape stack structure is pressed together by a laminator or a warm isostatic press to form a green ceramic tape stack body 6, the thickness of which is approximately 110mm.

[0055] In the specific implementation of S5, atmospheric pressure sintering, gas pressure sintering or hot isostatic pressing is used to sinter the green ceramic belt stack 6 to prepare a solid electrolyte body 7, and the burn-off layer 5 is oxidized and burned off in a high temperature environment to form uniformly distributed burn-off voids on the solid electrolyte body 7.

[0056] In the specific implementation process, the green ceramic tape stack 6 is first pre-fired at 400-600℃ in an oxidizing atmosphere, so that the burn-off layer 5 is gradually oxidized and burned off and forms uniform burn-off voids. Then, under an isostatic pressure of 200MPa, the temperature is raised to 600-900℃ to further sinter the pre-fired green ceramic tape stack 6 to prepare the solid electrolyte body 7.

[0057] The specific implementation of S6 includes the following sub-steps: S6-11. Position the solid electrolyte body 7 with the burn-off voids facing upwards. Then, place the solid electrolyte body 7 into a vacuum filling machine. At an environment of 300-400℃, fill the burn-off voids of the solid electrolyte body 7 with polyimide melt. Continue to keep it at this temperature for 0.5-1h, and then cool it to room temperature according to the set cooling regime to form a solid electrolyte complex. S6-12. Select the side of the solid electrolyte body 7 with burn-off voids, and perform multi-wire cutting on the solid electrolyte body along the direction perpendicular to the burn-off voids, that is, multi-wire cutting along the X direction. The multi-wire cutting uses diamond wire with a diameter of 0.12mm and the wire spacing is set to 1mm. After multi-wire cutting, multiple gaps with a width of about 0.15mm will be formed on the solid electrolyte body. S6-13. Clean the solid electrolyte complex after multi-wire cutting and dry it completely; S6-14. Following S6-11, polyimide is filled into the slits formed by multi-wire cutting to prepare a solid electrolyte composite 8.

[0058] In the specific implementation of S7, a CNC wire saw is used to modify the solid electrolyte composite 8 to obtain a solid electrolyte composite 8 with a size of 180*112*100mm. By modifying the shape, the support layer material at the edge of the solid electrolyte composite 8 is removed, and the polymer 2 is evenly distributed on the outside of the solid electrolyte. When preparing the oxide solid electrolyte film, the polymer 2 can protect each independent solid electrolyte unit 1.

[0059] In the specific implementation of S8, the solid electrolyte composite 8 is cut along the Y direction using multi-wire cutting. During the cutting, tungsten-diamond wire with a diameter of 28μm is selected, and the wire spacing is set to 33μm. After cutting, multiple solid electrolyte films with a thickness of 30μm and a length and width of 180*100mm are obtained.

[0060] In the specific implementation of S9, the thinning treatment of polymer 2 can be carried out on one side or both sides of the oxide solid electrolyte film simultaneously. One or more of chemical etching, physical etching, ion beam etching and thermal treatment can be selected for the thinning treatment to obtain an oxide solid electrolyte film with a thickness of polymer 2 that is less than the thickness of solid electrolyte unit 1.

[0061] During implementation, a polar solvent thinning method is used to thin the solid electrolyte membrane. A solvent with good solubility for polymer 2 is selected. The solid electrolyte membrane is completely immersed or one side is immersed or one side is coated with solvent, so that the surface polymer 2 is partially dissolved and removed in the solvent, thereby reducing the thickness of polymer 2.

[0062] In this embodiment, DMF (N,N-dimethylformamide) or NMP (N-methylpyrrolidone) is selected as a solvent, which has a good dissolving effect on polyimide. In the specific implementation process, the DMF solvent is stored in a sealed container, the solid electrolyte membrane is immersed in the DMF solvent, and immersed at 30-100°C for 5-24 hours. At the same time, the solvent is stirred at a constant speed to accelerate the dissolution of polyimide, thereby preparing an oxide solid electrolyte film with a polymer 2 thickness smaller than the solid electrolyte unit 1.

[0063] Reference Figure 8 In this embodiment, an oxide solid electrolyte film with a length and width of 180*100mm is prepared by performing S1-S9. The thickness of a single solid electrolyte unit 1 is 30μm and the length and width are 1*0.5mm. The thickness of the polymer 2 is 20μm. The uniform distribution of each solid electrolyte unit 1 on the oxide solid electrolyte film gives the oxide solid electrolyte film the advantages of high solid electrolyte density, excellent bending characteristics and high ionic conductivity.

[0064] Example 3: Reference Figures 3-7 This invention discloses a method for preparing an oxide solid electrolyte thin film. The difference between this embodiment and Embodiment 2 is that: In the specific implementation of S1, the solid electrolyte green ceramic strip 3 is a rectangular flexible sheet with a thickness of 1 mm and a length and width of 200*120 mm.

[0065] In the specific implementation of S2, a support layer 4 and a burn-off layer 5 are set on both sides of the solid electrolyte green ceramic belt 3. First, one surface is selected and lithium silicon zirconium phosphate paste is printed on the edge of the long side of the solid electrolyte green ceramic belt 3 through screen printing process, forming two parallel strip-shaped support layer 4 structures. After drying, the same operation is performed on the other side. The double-sided printed support layer 4 can provide better bonding force during lamination or warm isostatic pressing.

[0066] A carbon film is prepared by casting the slurry of the sintered layer and forming it. The thickness of the carbon film is twice that of the support layer 4. Then, the carbon film is punched to obtain a stacked carbon film that can be set in the region of the sintered layer 5. After that, the stacked carbon film is set in the region outside the support layer 4 by a positioning and stacking process. The solid electrolyte green ceramic tape 3 with the support layer 4 printed on both sides and the stacked carbon film are stacked in sequence to obtain the green ceramic tape stacked structure.

[0067] In a further implementation process, solid electrolyte 7 was prepared by performing S3-S5 according to Example 2.

[0068] The specific implementation of S6 includes the following sub-steps: S6-21. Select the side of the solid electrolyte body 7 with burn-off voids, and perform multi-wire cutting on the solid electrolyte body 7 along the direction perpendicular to the burn-off voids, that is, perform multi-wire cutting along the X direction. The multi-wire cutting uses diamond wire with a diameter of 0.12mm and the wire spacing is set to 1mm. After multi-wire cutting, multiple gaps with a width of about 0.15mm will be formed on the solid electrolyte body 7. S6-22. Clean the solid electrolyte body 7 after multi-wire cutting and dry it completely; S6-23. Position the solid electrolyte body 7 with the burn-off voids facing upwards. Then, place the solid electrolyte body 7 into a vacuum filling machine. At an environment of 300-400℃, fill the burn-off voids and cut gaps of the solid electrolyte body 7 with polyimide melt. Continue to keep it at this temperature for 0.5-1h, and then cool it to room temperature according to the set cooling regime to prepare the solid electrolyte composite 8.

[0069] In the specific implementation of S7, a CNC wire saw is used to modify the solid electrolyte composite 8 to obtain a solid electrolyte composite 8 with dimensions of 180*112*100mm.

[0070] In a further implementation process, an oxide solid electrolyte film with a thickness less than that of the solid electrolyte unit 1 was prepared by performing S8-S9 according to Example 2.

[0071] Reference Figure 9In this embodiment, an oxide solid electrolyte film with a length and width of 180*100mm is prepared by performing S1-S9. The thickness of a single solid electrolyte unit 1 is 30μm and the length and width are 1*1mm. The thickness of the polymer 2 is 20μm. The solid electrolyte units 1 are uniformly distributed on the oxide solid electrolyte film. The oxide solid electrolyte film has the same flexibility in the length and width directions.

[0072] Example 4: Reference Figures 3-6 This invention discloses a method for preparing an oxide solid electrolyte thin film. The difference between this embodiment and Embodiment 2 is that: In the specific implementation of S1, the solid electrolyte green ceramic strip 3 is a rectangular flexible sheet with a thickness of 1 mm and a length and width of 200*120 mm.

[0073] In a further implementation process, solid electrolyte 7 was prepared by performing S3-S5 according to Example 2.

[0074] In the specific implementation of S6, the burn-off voids of the solid electrolyte body 7 are positioned facing upwards. Then, the solid electrolyte body 7 is placed in a vacuum filling machine, and polyimide melt is filled into the burn-off voids of the solid electrolyte body 7 at an environment of 300-400℃. After continuing to keep it at this temperature for 0.5-1h, it is cooled to room temperature according to the set cooling regime to prepare the solid electrolyte composite 8.

[0075] In the specific implementation of S7, a CNC wire saw is used to modify the solid electrolyte composite 8 to obtain a solid electrolyte composite 8 with dimensions of 180*112*100mm.

[0076] In the specific implementation of S8, tungsten wire diamond wire with a diameter of 28μm is selected and the wire spacing is set to 2000μm. Multi-wire cutting is performed along the Y direction to obtain multiple solid electrolyte membranes with a thickness of 2000μm and a length and width of 180*100mm.

[0077] In the specific implementation of S9, a heat treatment thinning method is adopted to perform single-sided thinning treatment on the polymer 2 in the solid electrolyte membrane. The polymer 2 is softened by heating and then a certain pressure is applied to make it thinner.

[0078] In this embodiment, a solid electrolyte membrane is placed on a heating plate and heated to 300-400°C to heat the polyimide to a slightly softened state. Then, a fluororubber or polyurethane roller with a Shore hardness of 80-90HA is used to roll the solid electrolyte membrane. The roll burn-off gap is reasonably set according to the spacing of the solid electrolyte unit 1. Under the combined action of the pressure and deformation force of the fluororubber or polyurethane roller, the heated and softened polyimide is thinned, thereby preparing an oxide solid electrolyte film with a polymer 2 thickness smaller than the thickness of the solid electrolyte unit 1.

[0079] Reference Figure 10 In this embodiment, an oxide solid electrolyte film with a length and width of 180*100mm is prepared by performing S1-S9. The thickness of a single solid electrolyte unit 1 is 2000μm and the length and width are 180*1mm. The thickness of the polymer 2 is 500μm, which gives the oxide solid electrolyte film high strength. Moreover, the prepared oxide solid electrolyte film can only be bent in one direction, which meets the requirements of a specific solid battery for a solid electrolyte film.

[0080] Example 5: A solid-state battery disclosed in this invention includes an oxide solid-state electrolyte film prepared by the preparation method of the oxide solid-state electrolyte film of Example 2, Example 3, or Example 4, and also includes a positive electrode and a negative electrode. The oxide solid-state electrolyte film is disposed between the positive electrode and the negative electrode as a channel for the transfer of lithium ions or sodium ions. Since the solid electrolyte unit 1 on the oxide solid-state electrolyte film has a raised 3D structure, during the setting process, the raised part of the solid electrolyte unit 1 is embedded with the positive electrode material or the negative electrode material, so that the solid electrolyte film has a large contact area with the positive and negative electrodes, thereby improving the ionic conductivity of the solid-state battery.

[0081] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing an oxide solid electrolyte thin film, characterized in that, Includes the following steps: S1. A flexible solid electrolyte green ceramic belt was prepared by ceramic forming process (3). S2. A support layer (4) and a burn-off layer (5) are laid and covered on the surface of the solid electrolyte green ceramic belt (3). S3. Stack multiple solid electrolyte green ceramic tapes (3) in their own thickness direction to obtain a green ceramic tape stacked structure; S4. Press the stacked structure of green ceramic tapes together to form a stack of green ceramic tapes (6). S5. Sintering green ceramic belt stack (6) to oxidize the burn-off layer (5) at high temperature to form burn-off voids, and prepare a solid electrolyte body (7) with uniform burn-off voids. S6. Combine the polymer (2) with the solid electrolyte (7) to prepare a solid electrolyte composite (8). S7. The solid electrolyte complex (8) is modified. S8. The solid electrolyte composite (8) is cut by multiple lines to obtain a solid electrolyte membrane. S9. The polymer (2) in the solid electrolyte membrane is thinned to obtain an oxide solid electrolyte film with a polymer (2) thickness smaller than the solid electrolyte unit (1).

2. The method for preparing an oxide solid electrolyte thin film according to claim 1, characterized in that: In S2, the support layer (4) is prepared by screen printing, and the burn-off layer (5) is prepared by screen printing or by setting a burn-off layer film in a region other than the support layer (4).

3. The method for preparing an oxide solid electrolyte thin film according to claim 1, characterized in that: In S4, the green ceramic tape stack structure is pressed together by a laminator or a warm isostatic press to form a green ceramic tape stack body (6).

4. The method for preparing an oxide solid electrolyte thin film according to claim 1, characterized in that: S6 includes the following sub-steps: S6-11. Fill the burn-off voids of the solid electrolyte body (7) with polymer (2) to form a solid electrolyte complex. S6-12. Select the side of the solid electrolyte body (7) with burn-off voids, and make multi-line cuts on the solid electrolyte body along the direction perpendicular to the burn-off voids to form multi-line cut gaps. S6-13. Clean the solid electrolyte complex after multi-wire cutting and dry it completely; S6-14. Fill the gaps of the multi-line cutting with a polymer (2) to prepare a solid electrolyte composite (8).

5. The method for preparing an oxide solid electrolyte thin film according to claim 1, characterized in that: S6 includes the following sub-steps: S6-21. Select the side of the solid electrolyte body (7) with burn-off voids and perform multi-line cutting on the solid electrolyte body (7) along the direction perpendicular to the burn-off voids. S6-22. Clean the solid electrolyte body (7) after multi-wire cutting and dry it completely; S6-23. Fill the burn-off voids and cut gaps of the solid electrolyte (7) with polymer (2) to prepare a solid electrolyte composite (8).

6. The method for preparing an oxide solid electrolyte thin film according to claim 1, characterized in that: In S6, the polymer (2) fills the burn-off voids of the solid electrolyte (7).

7. The method for preparing an oxide solid electrolyte thin film according to claim 1, characterized in that: In S9, the thinning process of the polymer (2) includes one or more of chemical etching, physical etching, ion beam etching and thermal thinning.

8. An oxide solid electrolyte film, prepared by the method for preparing an oxide solid electrolyte film according to any one of claims 1 to 7, characterized in that: The film comprises multiple independent solid electrolyte units (1) and at least one polymer (2), wherein the polymer (2) is bonded to the multiple independent solid electrolyte units (1) to form an oxide solid electrolyte film. The thickness of the polymer (2) is less than the thickness of the solid electrolyte units (1). The thickness of a single solid electrolyte unit (1) is 10-2000 μm, and the surface area of ​​a single solid electrolyte unit (1) exposed to the outside is 0.01-300 mm². 2 .

9. The oxide solid electrolyte thin film according to claim 8, characterized in that: The polymer (2) contains a modified material that increases ionic conductivity.

10. A solid-state battery, comprising an oxide solid-state electrolyte film prepared by the method for preparing an oxide solid-state electrolyte film according to any one of claims 1 to 7, characterized in that: The solid-state battery also includes a positive electrode and a negative electrode, with the oxide solid electrolyte film disposed between the positive and negative electrodes as a channel for ion transfer.

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