Multi-layer self-supporting type Li7La3Zr2O12-based electrolyte film, preparation method and application of multi-layer self-supporting type Li7La3Zr2O12-based electrolyte film

Abstract

The invention discloses a multi-layer self-supporting type Li7La3Zr2O12-based electrolyte film as well as a preparation method and application thereof, and relates to the field of solid electrolytes of all-solid-state batteries. The thin film is composed of oriented microporous layers on the two sides and a middle compact layer, the overall thickness of the thin film is 200-500 microns, and the preparation method of the thin film comprises the following steps that Li7La3Zr2O12-based electrolyte powder, a dispersing agent and a solvent are mixed and then subjected to ball milling, and slurry A is obtained; adding a binder into the slurry A, and carrying out ball milling to obtain slurry B; vacuumizing the slurry B to remove bubbles, uniformly scraping and covering the slurry on a glass substrate through a flow scraper, and transferring the glass substrate and the slurry B to a coagulating bath. Through structural design, the electrolyte film has the advantages of low ohmic impedance, uniform interface contact and high mechanical strength, and is simple in process, high in efficiency and low in cost.

Description

Technical Field

[0001] This invention relates to the field of solid electrolytes for all-solid-state batteries, and more particularly to a multilayer self-supporting Li7La3Zr2O 12 Electrolyte thin films, their preparation methods, and their applications. Background Technology

[0002] All-solid-state lithium batteries are considered the core of next-generation energy storage technology due to their high energy density and inherent safety. The "Action Plan for High-Quality Development of New Energy Storage Manufacturing Industry," issued in February 2025, explicitly states the need to "focus on developing advanced energy storage lithium battery products such as large-capacity, high-safety energy storage batteries and solid-state batteries for energy storage." The performance of solid electrolyte materials is a key factor determining the energy density, safety, and rate capability of next-generation high-energy-density all-solid-state lithium batteries. Therefore, developing high-performance, low-cost solid electrolytes is one of the key technologies for developing all-solid-state lithium batteries.

[0003] Garnet-type solid electrolyte Li7La3Zr2O 12 LLZO (Lithium-ion-metallic oxide) possesses advantages such as high ionic conductivity, a wide electrochemical window, stability to lithium metal, and atmospheric processing capability, making it a promising oxide-based solid electrolyte. However, the practical application of LLZO electrolytes still faces the following key challenges: high ohmic impedance, severely limiting overall ion transport efficiency; poor interfacial contact, easily leading to localized high current density and inducing lithium dendrite growth; and insufficient mechanical properties, as the single-structure LLZO struggles to balance ion transport and mechanical performance, especially during cycling where electrode volume changes can cause stress that easily leads to electrolyte cracking.

[0004] Therefore, this invention proposes a multilayer self-supporting Li7La3Zr2O 12 Electrolyte thin films, their preparation methods, and their applications. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a multilayer self-supporting Li7La3Zr2O12-based electrolyte film, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A multilayer self-supporting Li7La3Zr2O 12 The base electrolyte membrane consists of oriented microporous layers on both sides and a dense layer in the middle, with an overall thickness of 200-500 μm.

[0007] Preferably, the pore size of the oriented microporous layer is 10-110 μm, and the thickness of the intermediate dense layer is 20-60 μm.

[0008] A multilayer self-supporting Li7La3Zr2O 12 The method for preparing a base electrolyte thin film includes the following steps: S1: Passing through 100 parts by mass of Li7La3Zr2O 12 Slurry A is obtained by ball milling a mixture of basic electrolyte powder, 0.5-2 parts by mass of dispersant, and 55-70 parts by mass of solvent. S2: Add 6-10 parts by weight of binder to slurry A, and ball mill to obtain slurry B; S3: After removing air bubbles by vacuuming, slurry B is evenly coated onto the glass substrate using a flow scraper. The glass substrate, along with slurry B, is then transferred to a coagulation bath and left to stand for 1-2 hours. After curing, it is removed and dried. S4: The dried phase transformation green body is cut into 25mm diameter round pieces using a laser, and then the back surface of the green body is modified with a laser until all the straight holes inside the green body are exposed, thus obtaining a directional microporous layer. S5: Add 100 parts by weight of Li7La3Zr2O 12 Slurry C is obtained by ball milling basic electrolyte powder, 100-200 parts by weight of solvent, 2-6 parts by weight of binder, and 2-5 parts by weight of plasticizer; S6: Disperse slurry C using a spin coater and deposit it onto a smooth layer of a oriented microporous substrate; S7: The smooth surfaces of two oriented microporous substrates are tightly bonded together. Under the action of gravity, the oriented microporous layer structure on both sides and the dense layer in the middle are fully fused into an integral structure to obtain a symmetrical matrix. S8: Sinter the symmetrical matrix at 1100-1200℃ for 1-24h to obtain multilayer self-supporting Li7La3Zr2O. 12 Basic electrolyte membrane.

[0009] Preferably: In step S1, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 ; The dispersant is one of N-vinylpyrrolidone (PVP), triethanolamine, and fish oil. The solvent is one of N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

[0010] Preferably, in step S1, the ball milling speed is 300-500 rpm and the ball milling time is 18-24 h.

[0011] Preferably, in step S2, the binder is polyethersulfone (PES), the ball milling speed is 300-500 rpm, and the ball milling time is 18-24 h.

[0012] Preferably, in step S3, the coagulation bath is one of pure water, anhydrous ethanol, isopropanol, water, and a DMAC mixture.

[0013] Preferably: In step S5, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 ; The solvent is either isopropanol or anhydrous ethanol; The binder is polyvinyl butyral (PVB); the plasticizer is one of polyethylene glycol (PEG) and dibutyl phthalate (DBP).

[0014] Preferably, in step S5, the ball milling speed is 300-500 rpm and the ball milling time is 20-24 h.

[0015] A multilayer self-supporting Li7La3Zr2O 12 The application of the base electrolyte film is in all-solid-state batteries. The positive electrode active material of the all-solid-state battery is one of lithium cobalt oxide, lithium-rich manganese base oxide, lithium iron phosphate, and elemental sulfur; the negative electrode active material is one of metallic lithium and lithium alloy.

[0016] The beneficial effects of this invention are as follows: This invention, through structural design, enables the electrolyte film to have the advantages of low ohmic impedance, uniform interfacial contact, and high mechanical strength, and the process is simple, efficient, and low-cost. Attached Figure Description

[0017] Figure 1 This invention proposes a multilayer self-supporting Li7La3Zr2O 12 Flowchart of the preparation method of the base electrolyte thin film; Figure 2 This invention proposes a multilayer self-supporting Li7La3Zr2O 12 Oriented pores – dense – oriented pores of garnet Li7La3Zr2O 12 Electrolyte microstructure diagram; Figure 3 This invention proposes a multilayer self-supporting Li7La3Zr2O12-based electrolyte film with oriented porous-dense-oriented porous garnet Li. 6.5 La3Zr 2.5 Nb 0.5 O 12 Electrolyte surface morphology diagram; Figure 4 This invention proposes a multilayer self-supporting Li7La3Zr2O 12Charge-discharge curves of LiCoO2-based solid-state lithium batteries with oriented pore structure of electrolyte film. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0020] Example 1: A multilayer self-supporting Li7La3Zr2O 12 The base electrolyte membrane consists of oriented microporous layers on both sides and a dense layer in the middle, with an overall thickness of 260 μm.

[0021] The directional microporous layer has a micropore diameter of 15 μm and an intermediate dense layer thickness of 18 μm.

[0022] Example 2: A multilayer self-supporting Li7La3Zr2O 12 The base electrolyte membrane consists of oriented microporous layers on both sides and a dense layer in the middle, with an overall thickness of 400 μm.

[0023] The directional microporous layer has a micropore diameter of 60 μm and an intermediate dense layer thickness of 40 μm.

[0024] Example 3: A multilayer self-supporting Li7La3Zr2O 12 A method for preparing a base electrolyte thin film includes the following steps: S1: Passing through 100 parts by mass of Li7La3Zr2O 12 Slurry A is obtained by ball milling a mixture of basic electrolyte powder, 0.5 parts by mass of dispersant, and 55 parts by mass of solvent. S2: Add 6 parts by mass of binder to slurry A and ball mill to obtain slurry B; S3: After removing air bubbles by vacuuming, slurry B is evenly coated onto the glass substrate using a flow scraper. The glass substrate, along with slurry B, is then transferred to a coagulation bath and left to stand for 1-2 hours. After curing, it is removed and dried. S4: The dried phase transformation green body is cut into 25mm diameter round pieces using a laser, and then the back surface of the green body is modified with a laser until all the straight holes inside the green body are exposed, thus obtaining a directional microporous layer. S5: Add 100 parts by weight of Li7La3Zr2O 12 Slurry C is obtained by ball milling the basic electrolyte powder, 100 parts by weight of solvent, 2 parts by weight of binder, and 2 parts by weight of plasticizer. S6: Disperse slurry C using a spin coater and deposit it onto a smooth layer of a oriented microporous substrate; S7: The smooth surfaces of two oriented microporous substrates are tightly bonded together. Under the action of gravity, the oriented microporous layer structure on both sides and the dense layer in the middle are fully fused into an integral structure to obtain a symmetrical matrix. S8: The symmetrical matrix was sintered at 1100℃ for 1 hour to obtain a multilayer self-supporting Li7La3Zr2O. 12 Basic electrolyte membrane.

[0025] In step S1, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 Its nominal chemical composition is Li 6.5 La3Zr 1.5 Nb 0.5 O 12 .

[0026] In steps S3-S5: The dispersant is one of N-vinylpyrrolidone (PVP), triethanolamine, or fish oil.

[0027] The solvent is one of N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

[0028] The adhesive is polyethersulfone (PES); the coagulation bath is one of pure water, anhydrous ethanol, isopropanol, water and DMAC mixture.

[0029] The coagulant consists of PVP, NMP, PES, and water, or PVP, NMP, PES, and isopropanol.

[0030] In steps S4-S6: The solvent is either isopropanol or anhydrous ethanol.

[0031] The adhesive is polyvinyl butyral (PVB). The plasticizer is one of polyethylene glycol (PEG) and dibutyl phthalate (DBP).

[0032] Example 4: A multilayer self-supporting Li7La3Zr2O 12 A method for preparing a base electrolyte thin film includes the following steps: S1: Passing through 100 parts by mass of Li7La3Zr2O 12 Slurry A is obtained by ball milling a mixture of basic electrolyte powder, 1.25 parts by mass of dispersant, and 62.5 parts by mass of solvent. S2: Add 8 parts by mass of binder to slurry A and ball mill to obtain slurry B; S3: After removing air bubbles by vacuuming, slurry B is evenly coated onto the glass substrate using a flow scraper. The glass substrate along with slurry B is then transferred to a coagulation bath and left to stand for 1.5 hours. After curing, it is removed and dried. S4: The dried phase transformation green body is cut into 25mm diameter round pieces using a laser, and then the back surface of the green body is modified with a laser until all the straight holes inside the green body are exposed, thus obtaining a directional microporous layer. S5: Add 100 parts by weight of Li7La3Zr2O 12 Slurry C was obtained by ball milling the basic electrolyte powder, 150 parts by weight of solvent, 4 parts by weight of binder, and 3.5 parts by weight of plasticizer. S6: Disperse slurry C using a spin coater and deposit it onto a smooth layer of a oriented microporous substrate; S7: The smooth surfaces of two oriented microporous substrates are tightly bonded together. Under the action of gravity, the oriented microporous layer structure on both sides and the dense layer in the middle are fully fused into an integral structure to obtain a symmetrical matrix. S8: The symmetrical matrix was sintered at 1150℃ for 12 hours to obtain a multilayer self-supporting Li7La3Zr2O. 12 Basic electrolyte membrane.

[0033] In steps S3-S5: The dispersant is one of N-vinylpyrrolidone (PVP), triethanolamine, or fish oil.

[0034] The solvent is one of N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

[0035] The adhesive is polyethersulfone (PES); the coagulation bath is one of pure water, anhydrous ethanol, isopropanol, water and DMAC mixture.

[0036] The coagulant consists of PVP, NMP, PES, and water, or PVP, NMP, PES, and isopropanol.

[0037] In steps S4-S6: The solvent is either isopropanol or anhydrous ethanol.

[0038] The adhesive is polyvinyl butyral (PVB). The plasticizer is one of polyethylene glycol (PEG) and dibutyl phthalate (DBP).

[0039] Example 5: A multilayer self-supporting Li7La3Zr2O 12 A method for preparing a base electrolyte thin film includes the following steps: S1: Passing through 100 parts by mass of Li7La3Zr2O 12 Slurry A is obtained by ball milling a mixture of basic electrolyte powder, 2 parts by mass of dispersant and 70 parts by mass of solvent. S2: Add 10 parts by weight of binder to slurry A and ball mill to obtain slurry B; S3: After removing air bubbles by vacuuming, slurry B is evenly coated onto the glass substrate using a flow scraper. The glass substrate, along with slurry B, is then transferred to a coagulation bath and left to stand for 1-2 hours. After curing, it is removed and dried. S4: The dried phase transformation green body is cut into 25mm diameter round pieces using a laser, and then the back surface of the green body is modified with a laser until all the straight holes inside the green body are exposed, thus obtaining a directional microporous layer. S5: Add 100 parts by weight of Li7La3Zr2O 12 Slurry C was obtained by ball milling the basic electrolyte powder, 200 parts by weight of solvent, 6 parts by weight of binder, and 5 parts by weight of plasticizer. S6: Disperse slurry C using a spin coater and deposit it onto a smooth layer of a oriented microporous substrate; S7: The smooth surfaces of two oriented microporous substrates are tightly bonded together. Under the action of gravity, the oriented microporous layer structure on both sides and the dense layer in the middle are fully fused into an integral structure to obtain a symmetrical matrix. S8: The symmetrical matrix was sintered at 1200℃ for 24 hours to obtain a multilayer self-supporting Li7La3Zr2O. 12 Basic electrolyte membrane.

[0040] In steps S3-S5: The dispersant is one of N-vinylpyrrolidone (PVP), triethanolamine, or fish oil.

[0041] The solvent is one of N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

[0042] The adhesive is polyethersulfone (PES); the coagulation bath is one of pure water, anhydrous ethanol, isopropanol, water and DMAC mixture.

[0043] The coagulant consists of PVP, NMP, PES, and water, or PVP, NMP, PES, and isopropanol.

[0044] In steps S4-S6: The solvent is either isopropanol or anhydrous ethanol.

[0045] The adhesive is polyvinyl butyral (PVB). The plasticizer is one of polyethylene glycol (PEG) and dibutyl phthalate (DBP).

[0046] Example 6: A multilayer self-supporting Li7La3Zr2O 12 A method for preparing a base electrolyte thin film includes the following steps: S1: Passing through 100 parts by mass of Li7La3Zr2O 12 Slurry A is obtained by ball milling a mixture of basic electrolyte powder, 0.5-2 parts by mass of dispersant, and 55-70 parts by mass of solvent. S2: Add 6-10 parts by weight of binder to slurry A, and ball mill to obtain slurry B; S3: After removing air bubbles by vacuuming, slurry B is evenly coated onto the glass substrate using a flow scraper. The glass substrate, along with slurry B, is then transferred to a coagulation bath and left to stand for 1-2 hours. After curing, it is removed and dried. S4: The dried phase transformation green body is cut into 25mm diameter round pieces using a laser, and then the back surface of the green body is modified with a laser until all the straight holes inside the green body are exposed, thus obtaining a directional microporous layer. S5: Add 100 parts by weight of Li7La3Zr2O 12 Slurry C is obtained by ball milling basic electrolyte powder, 100-200 parts by weight of solvent, 2-6 parts by weight of binder, and 2-5 parts by weight of plasticizer; S6: Disperse slurry C using a spin coater and deposit it onto a smooth layer of a oriented microporous substrate; S7: The smooth surfaces of two oriented microporous substrates are tightly bonded together. Under the action of gravity, the oriented microporous layer structure on both sides and the dense layer in the middle are fully fused into an integral structure to obtain a symmetrical matrix. S8: Sinter the symmetrical matrix at 1100-1200℃ for 1-24h to obtain multilayer self-supporting Li7La3Zr2O. 12 Basic electrolyte membrane.

[0047] In step S1, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 Its nominal chemical composition is Li 6.5 La3Zr 1.5 Nb 0.5 O 12 ; The dispersant is N-vinylpyrrolidone (PVP); The solvent is N-methylpyrrolidone (NMP).

[0048] In step S1, the ball milling speed is 300 rpm and the ball milling time is 24 h.

[0049] In step S2, the binder is polyethersulfone (PES), the ball milling speed is 300 rpm, and the ball milling time is 24 h.

[0050] In step S3, the coagulation bath is pure water.

[0051] In step S5, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 Its nominal chemical composition is Li 6.5 La3Zr 1.5 Nb 0.5 O 12 ; The solvent is isopropanol; The adhesive is polyvinyl butyral (PVB).

[0052] In step S5, the ball milling speed is 300 rpm and the ball milling time is 24 hours.

[0053] Example 7: A multilayer self-supporting Li7La3Zr2O 12 A method for preparing a base electrolyte thin film includes the following steps: S1: Passing through 100 parts by mass of Li7La3Zr2O 12 Slurry A is obtained by ball milling a mixture of basic electrolyte powder, 0.5-2 parts by mass of dispersant, and 55-70 parts by mass of solvent. S2: Add 6-10 parts by weight of binder to slurry A, and ball mill to obtain slurry B; S3: After removing air bubbles by vacuuming, slurry B is evenly coated onto the glass substrate using a flow scraper. The glass substrate, along with slurry B, is then transferred to a coagulation bath and left to stand for 1-2 hours. After curing, it is removed and dried. S4: The dried phase transformation green body is cut into 25mm diameter round pieces using a laser, and then the back surface of the green body is modified with a laser until all the straight holes inside the green body are exposed, thus obtaining a directional microporous layer. S5: Add 100 parts by weight of Li7La3Zr2O 12 Slurry C is obtained by ball milling basic electrolyte powder, 100-200 parts by weight of solvent, 2-6 parts by weight of binder, and 2-5 parts by weight of plasticizer; S6: Disperse slurry C using a spin coater and deposit it onto a smooth layer of a oriented microporous substrate; S7: The smooth surfaces of two oriented microporous substrates are tightly bonded together. Under the action of gravity, the oriented microporous layer structure on both sides and the dense layer in the middle are fully fused into an integral structure to obtain a symmetrical matrix. S8: Sinter the symmetrical matrix at 1100-1200℃ for 1-24h to obtain multilayer self-supporting Li7La3Zr2O. 12 Basic electrolyte membrane.

[0054] In step S1, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 Its nominal chemical composition is Li 6.5 La3Zr 1.5 Nb 0.5 O 12 ; The dispersant is triethanolamine; The solvent is dimethylacetamide (DMAC).

[0055] In step S1, the ball milling speed is 400 rpm and the ball milling time is 21 h.

[0056] In step S2, the binder is polyethersulfone (PES), the ball milling speed is 400 rpm, and the ball milling time is 21 h.

[0057] In step S3, the coagulation bath is anhydrous ethanol.

[0058] In step S5, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 Its nominal chemical composition is Li 6.5 La3Zr 1.5 Nb 0.5 O 12 ; The solvent is anhydrous ethanol; The adhesive is polyvinyl butyral (PVB); The plasticizer is dibutyl phthalate (DBP).

[0059] In step S5, the ball milling speed is 400 rpm and the ball milling time is 22 h.

[0060] Example 8: A multilayer self-supporting Li7La3Zr2O 12 A method for preparing a base electrolyte thin film includes the following steps: S1: Passing through 100 parts by mass of Li7La3Zr2O12 Slurry A is obtained by ball milling a mixture of basic electrolyte powder, 0.5-2 parts by mass of dispersant, and 55-70 parts by mass of solvent. S2: Add 6-10 parts by weight of binder to slurry A, and ball mill to obtain slurry B; S3: After removing air bubbles by vacuuming, slurry B is evenly coated onto the glass substrate using a flow scraper. The glass substrate, along with slurry B, is then transferred to a coagulation bath and left to stand for 1-2 hours. After curing, it is removed and dried. S4: The dried phase transformation green body is cut into 25mm diameter round pieces using a laser, and then the back surface of the green body is modified with a laser until all the straight holes inside the green body are exposed, thus obtaining a directional microporous layer. S5: Add 100 parts by weight of Li7La3Zr2O 12 Slurry C is obtained by ball milling basic electrolyte powder, 100-200 parts by weight of solvent, 2-6 parts by weight of binder, and 2-5 parts by weight of plasticizer; S6: Disperse slurry C using a spin coater and deposit it onto a smooth layer of a oriented microporous substrate; S7: The smooth surfaces of two oriented microporous substrates are tightly bonded together. Under the action of gravity, the oriented microporous layer structure on both sides and the dense layer in the middle are fully fused into an integral structure to obtain a symmetrical matrix. S8: Sinter the symmetrical matrix at 1100-1200℃ for 1-24h to obtain multilayer self-supporting Li7La3Zr2O. 12 Basic electrolyte membrane.

[0061] In step S1, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 Its nominal chemical composition is Li 6.5 La3Zr 1.5 Nb 0.5 O 12 ; The dispersant is fish oil; The solvent is dimethyl sulfoxide (DMSO).

[0062] In step S1, the ball milling speed is 500 rpm and the ball milling time is 18 h.

[0063] In step S2, the binder is polyethersulfone (PES), the ball milling speed is 500 rpm, and the ball milling time is 18 h.

[0064] In step S3, the coagulation bath is a mixture of water and DMAC.

[0065] In step S5, Li7La3Zr2O 12The base electrolyte powder is Nb-doped Li7La3Zr2O 12 Its nominal chemical composition is Li 6.5 La3Zr 1.5 Nb 0.5 O 12 ; The solvent is isopropanol; The adhesive is polyvinyl butyral (PVB); the plasticizer is one of dibutyl phthalate (DBP).

[0066] In step S5, the ball milling speed is 500 rpm and the ball milling time is 20 h.

[0067] Example 9: A multilayer self-supporting Li7La3Zr2O 12 The application of the base electrolyte thin film is in all-solid-state batteries, where the positive electrode active material is lithium cobalt oxide (LiCoO2) and lithium-rich manganese-based layered oxide (Li2Ni). x Co y Mn z O2, x + y + z = 1), lithium iron phosphate (LiFeO4), or elemental sulfur; the negative electrode active material is either metallic lithium or a lithium alloy.

[0068] The preparation of positive electrode materials for all-solid-state batteries includes the following steps: 70-85% by mass of positive electrode active material, 2-10% by mass of lithium salt (one of lithium hexafluorophosphate and lithium bis(trifluoromethanesulfonyl)imide), and 5-10% by mass of conductive agent acetylene black are ground and mixed; 5-10% by mass of polyvinylidene fluoride (PVDF) and 1-methyl-2-pyrrolidone (NMP) are added and ground and mixed to obtain an electrode material slurry; metallic lithium and metallic lithium alloys are directly used as the corresponding negative electrode materials.

[0069] All-solid-state battery assembly includes coin cells and pouch cells. The assembly process involves pouring the positive electrode slurry and the negative electrode melt into the directional microporous layers on both sides, respectively.

[0070] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A multilayer self-supporting Li7La3Zr2O 12 The base electrolyte thin film is characterized by, It consists of oriented microporous layers on both sides and a dense layer in the middle, with an overall thickness of 200-500μm.

2. A multilayer self-supporting Li7La3Zr2O according to claim 1 12 The base electrolyte thin film is characterized by, The directional microporous layer has a micropore diameter of 10-110 μm and an intermediate dense layer thickness of 20-60 μm.

3. A multilayer self-supporting Li7La3Zr2O 12 A method for preparing a base electrolyte thin film, used to prepare the multilayer self-supporting Li7La3Zr2O as described in claim 1 or 2. 12 The base electrolyte thin film is characterized by, Includes the following steps: S1: Passing through 100 parts by mass of Li7La3Zr2O 12 Slurry A is obtained by ball milling a mixture of basic electrolyte powder, 0.5-2 parts by mass of dispersant, and 55-70 parts by mass of solvent. S2: Add 6-10 parts by weight of binder to slurry A, and ball mill to obtain slurry B; S3: After removing air bubbles by vacuuming, slurry B is evenly coated onto the glass substrate using a flow scraper. The glass substrate, along with slurry B, is then transferred to a coagulation bath and left to stand for 1-2 hours. After curing, it is removed and dried. S4: The dried phase transformation green body is cut into 25mm diameter round pieces using a laser, and then the back surface of the green body is modified with a laser until all the straight holes inside the green body are exposed, thus obtaining a directional microporous layer. S5: Add 100 parts by weight of Li7La3Zr2O 12 Slurry C is obtained by ball milling basic electrolyte powder, 100-200 parts by weight of solvent, 2-6 parts by weight of binder, and 2-5 parts by weight of plasticizer; S6: Disperse slurry C using a spin coater and deposit it onto a smooth layer of a oriented microporous substrate; S7: The smooth surfaces of two oriented microporous substrates are tightly bonded together. Under the action of gravity, the oriented microporous layer structure on both sides and the dense layer in the middle are fully fused into an integral structure to obtain a symmetrical matrix. S8: Sinter the symmetrical matrix at 1100-1200℃ for 1-24h to obtain multilayer self-supporting Li7La3Zr2O. 12 Basic electrolyte membrane.

4. A multilayer self-supporting Li7La3Zr2O according to claim 3 12 A method for preparing a base electrolyte thin film, characterized in that, In step S1, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 ; The dispersant is one of N-vinylpyrrolidone (PVP), triethanolamine, and fish oil. The solvent is one of N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

5. A multilayer self-supporting Li7La3Zr2O according to claim 3 12 A method for preparing a base electrolyte thin film, characterized in that, In step S1, the ball milling speed is 300-500 rpm and the ball milling time is 18-24 h.

6. A multilayer self-supporting Li7La3Zr2O according to claim 3 12 A method for preparing a base electrolyte thin film, characterized in that, In step S2, the binder is polyethersulfone (PES), the ball milling speed is 300-500 rpm, and the ball milling time is 18-24 h.

7. A multilayer self-supporting Li7La3Zr2O according to claim 3 12 A method for preparing a base electrolyte thin film, characterized in that, In step S3, the coagulation bath is one of pure water, anhydrous ethanol, isopropanol, water, and a DMAC mixture.

8. A multilayer self-supporting Li7La3Zr2O according to claim 3 12 A method for preparing a base electrolyte thin film, characterized in that, In step S5, Li7La3Zr2O 12 The base electrolyte powder is Nb-doped Li7La3Zr2O 12 ; The solvent is either isopropanol or anhydrous ethanol; The binder is polyvinyl butyral (PVB); the plasticizer is one of polyethylene glycol (PEG) and dibutyl phthalate (DBP).

9. A multilayer self-supporting Li7La3Zr2O according to claim 3 12 A method for preparing a base electrolyte thin film, characterized in that, In step S5, the ball milling speed is 300-500 rpm and the ball milling time is 20-24 h.

10. A multilayer self-supporting Li7La3Zr2O according to claim 1 or 2 12 The application of the base electrolyte thin film is characterized by, It is used in all-solid-state batteries. The positive electrode active material of all-solid-state batteries is one of lithium cobalt oxide, lithium-rich manganese base oxide, lithium iron phosphate, and elemental sulfur; the negative electrode active material is one of metallic lithium and lithium alloy.

Images