A sulfide solid electrolyte membrane, a method for manufacturing the same, a solid-state battery, and a power-using device

Abstract

The application discloses a sulfide solid electrolyte film and a preparation method thereof, a solid-state battery and an electric device. The preparation method of the sulfide solid electrolyte film comprises the following steps: pre-mixing, mixing, calendering and annealing of a material containing sulfide electrolyte powder and a thermoplastic binder to obtain a sulfide solid electrolyte film, wherein the pre-mixing temperature T1 and the mixing temperature T2 satisfy T2 >= T m >= T1, and T m is the melting temperature of the thermoplastic binder. Through the temperature control strategy of pre-mixing, mixing, calendering and annealing, the distribution uniformity of the thermoplastic binder is effectively improved, the micro-defects are reduced, and the internal stress is eliminated, so that the ionic conductivity, mechanical strength and interface compatibility of the sulfide solid electrolyte film are improved, and good application prospect and industrialization value are exhibited.

Description

Technical Field

[0001] This application relates to the field of new energy technology, specifically to a sulfide solid electrolyte membrane and its preparation method, a solid battery, and an electrical device. Background Technology

[0002] With the rapid development of new energy vehicles and consumer electronics, the demand for high-energy-density and high-safety electrochemical energy storage devices is becoming increasingly urgent. All-solid-state lithium batteries, which use solid electrolytes instead of traditional liquid electrolytes, fundamentally solve the safety hazards of flammability and explosion, and are considered a core development direction for next-generation battery technology. In the all-solid-state battery technology route, sulfide solid electrolytes (such as Li6PS5Cl, Li...) are... 10 GeP2S 12 (etc.) because they have room-temperature ionic conductivity that is close to or even surpasses that of liquid electrolytes (up to 10). -2 It has the properties of being on the order of S / cm and has good mechanical ductility, making it easy to process into films, thus becoming one of the most commercially promising solid electrolyte materials.

[0003] The preparation methods of sulfide solid electrolyte membranes typically include wet and dry processes. The wet process involves dispersing sulfide electrolyte powder and a polymer binder in an organic solvent (such as butyl butyrate, xylene, acetonitrile, etc.) to form a slurry, which is then coated onto a substrate using methods such as blade coating or casting. After drying to remove the solvent, the electrolyte membrane is obtained. The wet process requires a large amount of organic solvent, which is not only costly but also requires recycling, increasing process complexity. Sulfide electrolytes are sensitive to polar solvents and are prone to side reactions with the solvent, leading to structural damage or the generation of toxic H2S gas. Furthermore, the solvent drying rate is slow, and it is difficult to completely remove the solvent during the drying process. Residual solvent degrades the ionic conductivity of the electrolyte membrane and can react with the lithium metal anode during battery cycling, making it difficult to meet the requirements of large-scale industrial production.

[0004] Dry processes for preparing sulfide electrolyte membranes represent an important development direction for solid sulfide electrolyte membranes due to the avoidance of solvent use. Existing dry processes primarily utilize the fibrillation property of polytetrafluoroethylene (PTFE) under shear force, causing PTFE to form a three-dimensional fiber network that "binds" electrolyte particles together to form a self-supporting membrane. In dry processes, PTFE fibrillation mainly relies on physical entanglement; the binder and sulfide particles only have physical contact, lacking chemical affinity, resulting in high interfacial impedance. Relying solely on physical fiber networks to bind particles is insufficient to completely eliminate interparticle porosity, leading to insufficient membrane density. Furthermore, the degree of PTFE fibrillation is extremely sensitive to parameters such as shear force and temperature, resulting in a narrow process window and difficulty in ensuring batch-to-batch stability of the membrane. Summary of the Invention

[0005] The purpose of this application is to overcome the problems existing in the prior art and provide a sulfide solid electrolyte membrane, its preparation method, solid battery, and power device.

[0006] The technical problem solved by this application is achieved by the following technical solution.

[0007] This application provides a method for preparing a sulfide solid electrolyte membrane, comprising the following steps: premixing, kneading, calendering, and annealing a material containing sulfide electrolyte powder and a thermoplastic binder to obtain a sulfide solid electrolyte membrane, wherein: the premixing temperature T1 and the kneading temperature T2 satisfy: T2≥T m ≥T1, T m The melting temperature of the thermoplastic adhesive is denoted as .

[0008] In some embodiments of this application, premixing the material comprising sulfide electrolyte powder and thermoplastic binder includes: heating the material comprising sulfide electrolyte powder and thermoplastic binder to T1 under a protective atmosphere, and maintaining (T1) the temperature. m -30)℃≤T1≤(T m The mixture is premixed at -10℃ to obtain a premixed material, wherein the protective atmosphere is selected from argon or nitrogen, and the water content and oxygen content in the protective atmosphere are both less than 0.1 ppm.

[0009] In some embodiments of this application, mixing the premix includes: heating the premixed material to T2 and maintaining T2 above T. m Mix at 20℃-100℃ and 30rpm-300rpm for 10min-60min to obtain the mixture.

[0010] In some embodiments of this application, calendering the compound includes: cooling the compound obtained by mixing to T3, and maintaining T3 below T. m Calendering is performed at 20℃-50℃ to obtain the primary film.

[0011] In some embodiments of this application, annealing the nascent membrane includes: heating the calendered nascent membrane to 80°C-150°C at a rate of 1°C / min-5°C / min, holding it at that temperature for 1h-12h, and then cooling it to room temperature at a rate of 0.5°C / min-2°C / min to obtain the sulfide solid electrolyte membrane.

[0012] In some embodiments of this application, the mass ratio of the sulfide electrolyte powder to the thermoplastic binder is 95:5 to 99:1; Preferably, the melting temperature T of the thermoplastic binder m The temperature range is 40℃-160℃, preferably 50℃-70℃; Preferably, the thermoplastic binder includes one or more of polyethylene oxide (PEO), polycaprolactone (PCL), polymethyl methacrylate (PMMA), and polyvinylidene fluoride (PVDF); Preferably, the sulfide electrolyte comprises Li 5.5 PS 4.5 C l1.5 Li 10 GeP2S 12 Li7P3S 11 One or more of Li3PS4 and Li4SnS4.

[0013] This application also provides a sulfide solid electrolyte membrane prepared by the above-described preparation method.

[0014] In some alternative embodiments, the sulfide solid electrolyte membrane has a thickness of 20 μm-30 μm, an ionic conductivity of 5 mS / cm-7 mS / cm, and a tensile strength of 3 MPa-5 MPa.

[0015] This application also provides a solid-state battery, which includes a sulfide solid electrolyte membrane prepared by the above-described preparation method and / or the above-described sulfide solid electrolyte membrane.

[0016] This application also provides an electrical device, which includes the solid-state battery described above.

[0017] This application has the following beneficial effects: This application utilizes a temperature control strategy involving premixing, mixing, calendering, and annealing to effectively improve the uniformity of thermoplastic binder distribution, reduce micro-defects, and eliminate internal stress. This results in the successful preparation of a sulfide solid electrolyte membrane that combines high ionic conductivity, good mechanical properties, and excellent interfacial compatibility, demonstrating promising application prospects and industrialization value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a comparison chart of the 0.1C first-cycle charge-discharge curves of the all-solid-state batteries assembled in Example 1 and Comparative Example 1 of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0021] The following is a detailed description of a sulfide solid electrolyte membrane, its preparation method, solid battery, and power device provided in the embodiments of this application.

[0022] In a first aspect, this application provides a method for preparing a sulfide solid electrolyte membrane, comprising the following steps: premixing, kneading, calendering, and annealing a material containing sulfide electrolyte powder and a thermoplastic binder to obtain a sulfide solid electrolyte membrane, wherein: the premixing temperature T1 and the kneading temperature T2 satisfy: T2≥T m ≥T1, T m The melting temperature of the thermoplastic adhesive is denoted as .

[0023] The above-described method for preparing sulfide solid electrolyte membranes involves first premixing materials containing sulfide electrolyte powder and a thermoplastic binder at temperature T1. This allows the thermoplastic binder to pre-coat the sulfide electrolyte particles in a semi-solid, high-viscosity state, preventing rapid melting and agglomeration. The temperature is then raised to T2 for mixing, maintaining the mixing temperature T2 above the melting temperature T of the thermoplastic binder. m The thermoplastic binder is molten at high temperatures and in situ wets the surface of the sulfide electrolyte particles, forming a tight interface that significantly reduces interfacial impedance. Compared to the purely physical winding method of PTFE fiberization, the sulfide solid electrolyte membrane preparation method provided in this application results in a higher interfacial bonding strength between the sulfide electrolyte particles and the thermoplastic binder, leading to smoother ion transport. Furthermore, the continuous polymer network endows the sulfide solid electrolyte membrane with excellent flexibility, resulting in a membrane that combines high ionic conductivity, good mechanical properties, and excellent interfacial compatibility, demonstrating promising application prospects and industrialization value.

[0024] In some alternative embodiments, premixing the material comprising sulfide electrolyte powder and thermoplastic binder includes: heating the material comprising sulfide electrolyte powder and thermoplastic binder to T1 under a protective atmosphere and maintaining (T1) the temperature. m -30)℃≤T1≤(T mPremixing is performed at -10℃ to obtain a premixed material, wherein: the protective atmosphere is selected from argon or nitrogen, and the water content and oxygen content in the protective atmosphere are both less than 0.1 ppm. Compared with the method of premixing materials containing sulfide electrolyte powder and thermoplastic binder at room temperature, the method for preparing sulfide solid electrolyte membrane provided in this application premixes materials containing sulfide electrolyte powder and thermoplastic binder at a temperature T1, wherein the premixing temperature T1 satisfies: (T m -30)℃≤T1≤(T m -10)℃, controlling the premixing temperature T1 to be slightly lower than the melting temperature T of the thermoplastic binder. m This allows the thermoplastic binder to be in a semi-solid, high-viscosity state, pre-coating sulfide electrolyte particles in this state, thus avoiding uneven mixing caused by rapid melting and agglomeration.

[0025] In some alternative embodiments, mixing the premix includes: heating the premixed material to T2 and maintaining T2 above T. m The mixture is kneaded at 20℃-100℃ and 30rpm-300rpm for 10min-60min to obtain a compound. For example, the kneading speed can be any value between 30rpm, 50rpm, 100rpm, 150rpm, 200rpm, 250rpm, 300rpm, and 30rpm-300rpm, and the kneading time can be any value between 10min, 20min, 30min, 40min, 50min, 60min, and 10min-60min. During the kneading process, the premixed material is heated to T2 and maintained above T. m The mixing temperature T2 must be significantly higher than the melting temperature T of the thermoplastic binder, between 20℃ and 100℃. m The thermoplastic binder is melted, and the molten thermoplastic binder gives the composite system better fluidity. Through shear force, the thermoplastic binder is forced to penetrate into the interparticle gaps of the sulfide electrolyte, breaking up soft agglomerates and achieving uniform coating and interface wetting. In subsequent calendering or extrusion molding, it can effectively fill the interparticle gaps of the sulfide electrolyte, forming a dense film structure without pores or with micropores, thus solving the problem of high brittleness of traditional dry-process films.

[0026] In some alternative embodiments, calendering the compound includes: cooling the compound to T3 and maintaining T3 below T. m The calendering process is performed at 20℃-50℃ to obtain the nascent film. Preferably, the compound obtained from the mixing process is calendered at a temperature 25-40℃ below Tm to obtain the nascent film. For example, the calendering temperature of the premix can be below Tm. m10℃, 20℃, 30℃, 40℃, 50℃ and below T m Any other value between 20℃ and 50℃. Unlike molding methods that involve calendering or extrusion above the binder's melting temperature, the compound in this application uses only calendering to prepare the initial film during the molding process. In this case, the calendering temperature T3 must be lower than the melting temperature T of the thermoplastic binder. m This process allows the molten thermoplastic binder to cool and solidify during calendering, preventing it from flowing back and re-agglomerating at high temperatures for extended periods, or causing microcracks due to thermal shrinkage, thus ensuring the film's density and mechanical strength. It is worth noting that the method for preparing the sulfide solid electrolyte membrane provided in this application involves mixing the compounded material at temperatures below T... m The nascent film is obtained by calendering at a temperature of 20-50℃. This step does not use biaxial stretching or extrusion thinning, which avoids uneven orientation, internal stress and thickness deviation of the film, resulting in a more uniform and dense structure; it does not cause pore enlargement or damage to ion conduction pathways due to stretching, thus ensuring conductivity; at the same time, it reduces film cracking and deformation problems, resulting in better dimensional stability and a simpler and easier-to-control process.

[0027] In some optional embodiments, annealing the nascent membrane includes: heating the calendered nascent membrane to 80°C-150°C at a rate of 1°C / min-5°C / min, holding the anneal at that temperature for 1h-12h, and then cooling it to room temperature at a rate of 0.5°C / min-2°C / min to obtain the sulfide solid electrolyte membrane. Preferably, the annealing holding time is 2h-8h. For example, during the annealing of the nascent film, the heating rate can be any other value between 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, and 1℃ / min-5℃ / min; the annealing temperature can be any other value between 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, and 80℃-150℃; the annealing time can be any other value between 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, and 1h-12h; and the cooling rate after annealing can be any other value between 0.5℃ / min, 1.0℃ / min, 1.5℃ / min, 2.0℃ / min, and 0.5℃ / min-2℃ / min. Because residual thermal and mechanical stresses remain in the film after mixing and calendering, a short-time heat setting process (a few minutes) is insufficient to fully relax the polymer chains, resulting in inadequate long-term cycle stability. Direct natural cooling to room temperature leads to uncontrollable crystal structure of the thermoplastic binder, which is detrimental to improving ionic conductivity. To overcome these defects, the nascent film described in this application employs a slow heating + long-term holding + slow cooling process during annealing to fully eliminate the internal stress of the calendered nascent film, relax the polymer chains, and improve the long-term cycle stability of the sulfide electrolyte film.

[0028] In some optional embodiments, the mass ratio of the sulfide electrolyte powder to the thermoplastic binder is 95:5 to 99:1. When the proportion of sulfide electrolyte powder is too high, the membrane is prone to brittleness and poor formability; when the proportion of thermoplastic binder is too high, it will block ion conduction, reduce conductivity, and increase interfacial impedance. In this application, controlling the appropriate ratio of the two is necessary to ensure that the sulfide solid electrolyte membrane has both good ion conductivity and mechanical properties. Preferably, the melting temperature T of the thermoplastic binder m The temperature range is 40℃-160℃, preferably 50℃-70℃; Preferably, the thermoplastic binder includes one or more of polyethylene oxide (PEO), polycaprolactone (PCL), polymethyl methacrylate (PMMA), and polyvinylidene fluoride (PVDF); Preferably, the sulfide electrolyte comprises Li 5.5 PS 4.5 C l1.5 Li10 GeP2S 12 Li7P3S 11 One or more of Li3PS4 and Li4SnS4.

[0029] It is worth noting that, in addition to binders and the sulfide electrolyte itself, inorganic fillers can be added to improve ionic conductivity in the preparation of sulfide solid electrolyte membranes, the mechanical strength can be guaranteed by relying on the polymer skeleton, and functional additives can be used to solve self-healing or air stability issues.

[0030] In some optional embodiments, the method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1, Low-Temperature Premixing: Under a protective atmosphere, the materials containing sulfide electrolyte powder and thermoplastic binder are mixed at temperature T1 to obtain a premix; the premixing temperature T1 satisfies: T m -30℃≤T1≤T m -10℃, where T m This refers to the melting temperature of the thermoplastic adhesive.

[0031] Step 2, Heating and Mixing: Heating the premix obtained in Step 1 to T2, and maintaining T2 higher than T. m Mix at 20℃-100℃ and 30rpm-300rpm for 10min-60min to obtain the mixture.

[0032] Step 3, Low-Temperature Calendering: The compound obtained in Step 2 is cooled to T3, and calendered at a temperature that maintains T3 20℃-50℃ below Tm to obtain the primary film. This step does not use biaxial stretching or extrusion thinning.

[0033] Step 4, Programmed annealing: The nascent membrane obtained in step 3 is heated to 80℃-150℃ at a rate of 1℃ / min-5℃ / min, held for annealing for 1h-12h, and then cooled to room temperature at a rate of 0.5℃ / min-2℃ / min to obtain the sulfide solid electrolyte membrane.

[0034] Secondly, this application also provides a sulfide solid electrolyte membrane prepared by the above-described preparation method.

[0035] In some alternative embodiments, the sulfide solid electrolyte membrane has a thickness of 20 μm-30 μm, an ionic conductivity of 5 mS / cm-7 mS / cm, and a tensile strength of 3 MPa-5 MPa.

[0036] Thanks to the reduction in interfacial impedance and the increase in the density of the sulfide solid electrolyte membrane, the room temperature ionic conductivity of the sulfide solid electrolyte membrane prepared in this application can reach more than 5 mS / cm, which meets the application requirements of all-solid-state batteries.

[0037] Thirdly, this application also provides a solid-state battery, the solid-state battery comprising a sulfide solid electrolyte membrane prepared by the above-described preparation method and / or the above-described sulfide solid electrolyte membrane.

[0038] Typically, a solid-state battery includes a positive electrode, a negative electrode, and a sulfide solid electrolyte membrane disposed between the negative electrode and the positive electrode. The sulfide solid electrolyte membrane is prepared using the preparation method described above.

[0039] In some alternative embodiments, the positive electrode active material layer in the positive electrode sheet may be disposed on one or both surfaces of the positive electrode current collector.

[0040] Those skilled in the art can choose a suitable method to prepare the positive electrode sheet. For example, it may include the following steps: mixing positive active material, binder and conductive agent to form a slurry, and then coating it onto the positive current collector.

[0041] The specific type of positive electrode active material is not particularly limited, as long as it can satisfy the requirements for lithium ion insertion and extraction. The positive electrode active material can be a layered structure material, allowing lithium ions to diffuse in two-dimensional space, or a spinel structure, allowing lithium ions to diffuse in three-dimensional space. Preferably, the positive electrode active material can be selected from one or more of lithium transition metal oxides, or compounds obtained by adding other transition metals, non-transition metals, or non-metals to lithium transition metal oxides. Specifically, the positive electrode active material is preferably selected from one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide.

[0042] In the positive electrode sheet, the positive electrode active material layer may further include a conductive agent and a binder. The type and content of the conductive agent and binder are not specifically limited and can be selected according to actual needs. The binder typically includes fluorinated polyolefin binders. Water is usually a good solvent for the fluorinated polyolefin binder, meaning that the fluorinated polyolefin binder typically has good solubility in water. For example, the fluorinated polyolefin binder may be, but is not limited to, polyvinylidene fluoride (PVDF), PVDF copolymers, or their modified derivatives (e.g., modified with carboxylic acid, acrylic acid, acrylonitrile, etc.). The mass percentage content of the binder in the positive electrode material layer may be limited because the binder itself has poor conductivity, therefore the amount of binder cannot be too high. The conductive agent in the positive electrode sheet can be any conductive agent suitable for secondary batteries in the art, for example, it may be one or more of the following, including but not limited to superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0043] In the positive electrode sheet, the type of positive current collector is not specifically limited and can be selected according to actual needs. The positive current collector is typically a layer, and is usually a structure or component capable of collecting current. The positive current collector can be any material suitable for use as a positive current collector in electrochemical energy storage devices. For example, the positive current collector can be, but is not limited to, metal foil, and more specifically, can be, but is not limited to, nickel foil and aluminum foil.

[0044] In some alternative embodiments, the negative electrode typically includes a negative current collector and a negative active material layer located on the surface of the negative current collector, the negative active material layer typically comprising a negative active material.

[0045] Those skilled in the art can choose a suitable method to prepare the negative electrode sheet. For example, it may include the following steps: mixing the negative electrode active material, binder and conductive agent to form a slurry, and then coating it onto the negative electrode current collector.

[0046] The negative electrode active material can be any material suitable for lithium-ion secondary batteries, including but not limited to artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material can be selected from one or more of elemental silicon, silicon-oxygen compounds, silicon-carbon compounds, silicon-nitrogen compounds, and silicon alloys. The tin-based material can be selected from one or more of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0047] The negative electrode current collector is typically a structure or component that collects current. It can be any material suitable for use as a negative electrode current collector in a lithium secondary battery, for example, it can be, but is not limited to, metal foil, and more specifically, copper foil. Furthermore, the negative electrode sheet can also be a lithium sheet.

[0048] In some implementations, the positive electrode, negative electrode, and solid electrolyte membrane can be fabricated into a battery cell using a winding or stacking process.

[0049] In some alternative embodiments, the aforementioned battery cells can be assembled into a battery module, and the number of battery cells contained in the battery module can be multiple, the specific number of which can be adjusted according to the application and capacity of the battery module.

[0050] In some alternative embodiments, the battery modules described above can be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0051] Fourthly, this application also provides an electrical device, which includes the aforementioned solid-state battery.

[0052] The electrical device provided in this application may include the aforementioned battery cells, battery modules, or battery packs. The aforementioned battery cells, battery modules, or battery packs can be used as the power source for the electrical device or as the energy storage unit for the electrical device. The electrical device may be, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0053] The electrical device can be configured to use individual battery cells, battery modules, or battery packs according to its usage requirements.

[0054] In specific implementations, the electrical device can be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the lithium-ion battery for this electrical device, a battery pack or battery module can be used. Another example of an electrical device could be a mobile phone, tablet computer, laptop computer, etc.

[0055] Those skilled in the art will understand that the various limitations or optional ranges for the selection of components, component content and physicochemical properties of materials in the different embodiments of this application mentioned above can be arbitrarily combined, and the various embodiments obtained by such combinations are still within the scope of this application and are considered as part of the disclosure of this specification.

[0056] Unless otherwise specified, the various parameters mentioned in this specification have general meanings known in the art and can be measured using methods known in the art. For example, they can be tested according to the methods given in the embodiments of this application. In addition, the optional ranges and options of various parameters given in the various optional embodiments can be combined arbitrarily, and all such combinations are considered to be within the scope of disclosure of this application.

[0057] The advantages of this application are further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application.

[0058] This application provides a method for preparing a sulfide solid electrolyte membrane, comprising the following steps: Step 1: Low-temperature premixing A method for preparing a sulfide solid electrolyte membrane includes the following steps: Under a protective atmosphere (argon or nitrogen, with water and oxygen content both below 0.1 ppm), sulfide electrolyte powder and thermoplastic binder are mixed at temperature T1 to obtain a premix; the temperature T1 satisfies: T m -30℃≤T1≤T m -10℃, where: T m This refers to the melting temperature of the thermoplastic adhesive.

[0059] Step 2: Heating and mixing The premix is ​​heated to temperature T2, and T2 is maintained above T. m Mixing is carried out at 20℃-100℃ and rotor speed of 30rpm-300rpm for 10-60 minutes to obtain the mixed material.

[0060] Step 3: Low-temperature calendering The resulting mixture is cooled to T3, and T3 is kept below T. m The nascent film is obtained by calendering at a temperature of 20℃-50℃. This step does not involve biaxial stretching or extrusion thinning.

[0061] Step 4: Programmed annealing The calendered nascent membrane is heated to 80℃-150℃ at a rate of 1℃ / min-5℃ / min, held for annealing for 1h-12h, and then cooled to room temperature at a rate of 0.5℃ / min-2℃ / min to obtain the sulfide solid electrolyte membrane.

[0062] The melting temperature T of the thermoplastic adhesive used above m The temperature range is 40℃-160℃.

[0063] The thermoplastic binder includes one or more of polyethylene oxide (PEO), polycaprolactone (PCL), polymethyl methacrylate (PMMA), and polyvinylidene fluoride (PVDF).

[0064] The sulfide solid electrolyte includes Li 5.5 PS 4.5 C l1.5 Li 10 GeP2S 12 Li7P3S 11 One or more of Li3PS4 and Li4SnS4.

[0065] Example 1 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5(LPSCl) powder and PEO (Mn=300,000, T) m Mix (at a mass ratio of 98:2) at 65℃, and heat at 50℃ (T) m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0066] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0067] Example 2 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m =65℃) Mix at a mass ratio of 98:2, and heat at 55℃ (T m The premix was obtained by mixing at 50 rpm for 30 min at -10℃.

[0068] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 8 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0069] Example 3 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PCL (Tm=58℃) are mixed at a mass ratio of 98:2 and heated at 40℃ (Tm=58℃). mThe premix was obtained by mixing at 50 rpm for 30 min at -18℃.

[0070] Step 2: Heat the premix obtained in Step 1 to 130℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 30℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 90°C at 2°C / min, hold for 4 h, and then cool to room temperature at 1°C / min; press to 25 μm, and roll up to obtain a sulfide solid electrolyte membrane.

[0071] Example 4 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and LGPS are mixed at a mass ratio of 98:2 and heated at 50℃ (T m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0072] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0073] Example 5 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PMMA (polymethyl methacrylate, Mn=120,000, T) m =130℃) Mixed at a mass ratio of 98:2, and heated at 115℃ (T m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0074] Step 2: Heat the premix obtained in Step 1 to 180℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 95℃ (below T). m The primary film is obtained by calendering at 35℃. Step 4: Heat the nascent membrane obtained in Step 3 to 120℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0075] Example 6 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PVDF (polyvinylidene fluoride, Mn=200,000, T) m =170℃) Mixed at a mass ratio of 98:2, and heated at 145℃ (T m The premix was obtained by mixing at 50 rpm for 30 min at -25℃.

[0076] Step 2: Heat the premix obtained in Step 1 to 220℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 135℃ (below T). m The primary film is obtained by calendering at 35℃. Step 4: Heat the nascent membrane obtained in Step 3 to 140℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0077] Example 7 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (T) in a 1:1 mass ratio m =65℃) and PCL (T m =58℃) Mix the adhesive (2% of the total adhesive by mass), and at 45℃ (lower than the lower T) m The premix was obtained by mixing at 50 rpm for 30 min at approximately 13°C.

[0078] Step 2: Heat the premix obtained in Step 1 to 135℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 35℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 95°C at 2°C / min, hold for 4 h, and then cool to room temperature at 1°C / min; press to 25 μm, and roll up to obtain a sulfide solid electrolyte membrane.

[0079] Comparative Example 1 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m =65℃) Mix at a mass ratio of 98:2, mix at room temperature to obtain a premix.

[0080] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0081] Comparative Example 2 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m Mix (at a mass ratio of 98:2) at 65℃, and heat at 50℃ (T) m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0082] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 80℃ (above T). mThe primary film is obtained by calendering at 15℃. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0083] Comparative Example 3 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m Mix (at a mass ratio of 98:2) at 65℃, and heat at 50℃ (T) m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0084] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at a rate of 2℃ / min, hold for 4 h, and then cool naturally (cooling rate of about 20-30℃ / min) to room temperature; press to 25μm, and roll up to obtain a sulfide solid electrolyte membrane.

[0085] Comparative Example 4 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m =65℃) Mix at a mass ratio of 98:2, mix at room temperature to obtain a premix.

[0086] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 80℃ (above T). m The primary film is obtained by calendering at 15℃. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at a rate of 2℃ / min, hold for 4 h, and then cool naturally (cooling rate of about 20-30℃ / min) to room temperature; press to 25μm, and roll up to obtain a sulfide solid electrolyte membrane.

[0087] Comparative Example 5 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m =65℃) Mix at a mass ratio of 98:2, and heat at 25℃ (T m The premix was obtained by mixing at 50 rpm for 30 min at -40℃.

[0088] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0089] Comparative Example 6 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m =65℃) Mix at a mass ratio of 98:2, and heat at 60℃ (T m The premix was obtained by mixing at 50 rpm for 30 min at -5℃.

[0090] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0091] Comparative Example 7 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m Mix (at a mass ratio of 98:2) at 65℃, and heat at 50℃ (T) m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0092] Step 2: Heat the premix obtained in Step 1 to 75℃ (10℃ higher than Tm), set the rotor speed to 150 rpm, and mix for 30 min to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0093] Comparative Example 8 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m Mix (at a mass ratio of 98:2) at 65℃, and heat at 50℃ (T) m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0094] Step 2: Heat the premix obtained in Step 1 to 185℃ (120℃ higher than Tm), set the rotor speed to 150 rpm, and mix for 30 min to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0095] Comparative Example 9 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m Mix (at a mass ratio of 98:2) at 65℃, and heat at 50℃ (T) m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0096] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: The mixture obtained in Step 2 is calendered at 55℃ (10℃ below Tm) to obtain the primary film; Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0097] Comparative Example 10 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m Mix (at a mass ratio of 98:2) at 65℃, and heat at 50℃ (T) m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0098] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: The mixture obtained in Step 2 is calendered at 5℃ (below Tm 60℃) to obtain the primary film; Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, keep it at that temperature for 4 h, and then cool it to room temperature at 1℃ / min; press it to 25μm, and roll it up to obtain a sulfide solid electrolyte membrane.

[0099] Comparative Example 11 A method for preparing a sulfide solid electrolyte membrane includes the following steps: Step 1: In an argon glove box, place Li... 5.5 PS 4.5 Cl 1.5 (LPSCl) powder and PEO (Mn=300,000, T) m Mix (at a mass ratio of 98:2) at 65℃, and heat at 50℃ (T) m The premix was obtained by mixing at 50 rpm for 30 min at -15℃.

[0100] Step 2: Heat the premix obtained in Step 1 to 140℃, set the rotor speed to 150 rpm, and mix for 30 minutes to obtain the mixture. Step 3: Heat the mixture obtained in Step 2 at 40℃ (below T). m The primary film is obtained by calendering at 25°C. Step 4: Heat the nascent membrane obtained in Step 3 to 100℃ at 2℃ / min, hold for 0.5 h, and then cool to room temperature at 1℃ / min; press to 25μm, and roll up to obtain a sulfide solid electrolyte membrane.

[0101] Performance testing Ionic conductivity testing method: The electrochemical impedance spectroscopy (EIS) method is used. The electrolyte membrane is placed between blocking electrodes (stainless steel), and the impedance spectrum is measured at room temperature with a frequency range of 1Hz-1MHz and an amplitude of 10mV. The ionic conductivity is calculated using the formula σ=L / (R·S), where L is the membrane thickness, R is the bulk resistance, and S is the electrode area.

[0102] Tensile strength test: A universal tensile testing machine was used, referring to GB / T 1040.1-2025 standard. Sample size: length 50mm, width 10mm, tensile speed 5mm / min.

[0103] Battery performance testing: Solid-state batteries were assembled using NCM811 as the positive electrode and lithium indium alloy as the negative electrode. The 0.1C initial efficiency and 0.5C cycle performance were tested at 25℃. The comparison results of the 0.1C first-cycle charge-discharge curves are as follows: Figure 1 As shown.

[0104] Test Results Depend on Figure 1 It can be seen that the battery assembled using the sulfide solid electrolyte membrane of Example 1 has a significantly higher first-cycle charging capacity than that of Comparative Example 1, and also has less polarization. This is because the low-temperature premixing in Example 1 allows the binder to uniformly coat the sulfide electrolyte particles, reducing the interfacial impedance and making lithium-ion transport smoother. In contrast, the room-temperature premixing in Comparative Example 1 leads to binder agglomeration, interface deterioration, and a decrease in both capacity and efficiency.

[0105] The test results of the sulfide solid electrolyte membranes prepared in Examples 1-7 and Comparative Examples 1-11 are shown in Table 1.

[0106] Table 1. Test results of sulfide solid electrolyte membranes prepared in Examples 1-7 and Comparative Examples 1-11

[0107] As shown in Table 1 above, the sulfide solid electrolyte membranes prepared in Examples 1-7 of this application all exhibit excellent comprehensive performance, with Example 1 showing the best results. Example 1 achieved an ionic conductivity of 6.2 mS / cm, a tensile strength of 3.5 MPa, an initial efficiency of 88.1% at 0.1C, and a capacity retention rate of 86.1% after 100 cycles at 0.5C. In Comparative Examples 1-11, changing the conditions failed to produce sulfide solid electrolyte membranes that combined high ionic conductivity, good mechanical properties, and excellent interfacial compatibility.

[0108] The above results demonstrate that the synergistic temperature control strategy of low-temperature premixing, low-temperature calendering, and programmed annealing in this application can significantly improve the overall performance of sulfide solid electrolyte membranes. The preparation method of sulfide solid electrolyte membranes provided in this application does not depend on specific molecular weights or special functional groups, is applicable to conventional thermoplastic polymers, has a wide process window, and is low in cost.

[0109] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a sulfide solid electrolyte membrane, characterized in that, Includes the following steps: A sulfide solid electrolyte membrane is obtained by premixing, kneading, calendering, and annealing a material containing sulfide electrolyte powder and a thermoplastic binder, wherein the premixing temperature T1 and the kneading temperature T2 satisfy: T2≥T m ≥T1, T m The melting temperature of the thermoplastic adhesive is denoted as .

2. The preparation method according to claim 1, characterized in that, Premixing a material containing sulfide electrolyte powder and a thermoplastic binder includes: heating the material containing sulfide electrolyte powder and a thermoplastic binder to T1 under a protective atmosphere, and maintaining (T1) the temperature. m -30)℃≤T1≤(T m The mixture is premixed at -10℃ to obtain a premixed material, wherein the protective atmosphere is selected from argon or nitrogen, and the water content and oxygen content in the protective atmosphere are both less than 0.1 ppm.

3. The preparation method according to claim 2, characterized in that, The process of mixing the premix includes: heating the premixed material to T2 and maintaining T2 above T. m Mix at 20℃-100℃ and 30rpm-300rpm for 10min-60min to obtain the mixture.

4. The preparation method according to claim 3, characterized in that, Calendering the compound includes: cooling the compound obtained by mixing to T3, and maintaining T3 below T. m Calendering is performed at 20℃-50℃ to obtain the primary film.

5. The preparation method according to claim 4, characterized in that, Annealing the nascent membrane includes: heating the calendered nascent membrane to 80°C-150°C at a rate of 1°C / min-5°C / min, holding it at that temperature for 1-12 hours, and then cooling it to room temperature at a rate of 0.5°C / min-2°C / min to obtain the sulfide solid electrolyte membrane.

6. The preparation method according to claim 1, characterized in that, The mass ratio of the sulfide electrolyte powder to the thermoplastic binder is 95:5 to 99:1; Preferably, the melting temperature T of the thermoplastic binder m The temperature range is 40℃-160℃, preferably 50℃-70℃; Preferably, the thermoplastic binder includes one or more of polyethylene oxide (PEO), polycaprolactone (PCL), polymethyl methacrylate (PMMA), and polyvinylidene fluoride (PVDF); Preferably, the sulfide electrolyte comprises Li 5.5 PS 4.5 C l1.5 Li 10 GeP2S 12 Li7P3S 11 One or more of Li3PS4 and Li4SnS4.

7. A sulfide solid electrolyte membrane, characterized in that, It is prepared by the preparation method according to any one of claims 1-6.

8. The sulfide solid electrolyte membrane according to claim 7, characterized in that, The sulfide solid electrolyte membrane has a thickness of 20μm-30μm, an ionic conductivity of 5mS / cm-7mS / cm, and a tensile strength of 3MPa-5MPa.

9. A solid-state battery, characterized in that, The solid-state battery includes a sulfide solid electrolyte membrane prepared by the preparation method of any one of claims 1-6 and / or a sulfide solid electrolyte membrane of any one of claims 7-8.

10. An electrical appliance, characterized in that, The electrical device includes the solid-state battery as described in claim 9.

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