A solid electrolyte membrane, its preparation method and application

Abstract

This invention provides a solid electrolyte membrane, its preparation method, and its applications. The solid electrolyte membrane provided by this invention includes an electrolyte layer and a substrate layer. The electrolyte layer comprises a solid electrolyte material and a binder. The substrate layer undergoes surface modification treatment and is grafted with one, two, or more active functional groups. These active functional groups can polymerize with the binder to form a cross-linked network. The binder is an unsaturated binder. In the solid electrolyte membrane provided by this invention, the electrolyte layer and the substrate layer are connected through a cross-linked network formed by the polymerization of the active functional groups and the binder. This improves the strength and structural stability, avoiding the problem of easy detachment when the substrate is only in contact with one side of the electrolyte layer. It can also reduce the electronic conductivity of the electrolyte membrane and effectively suppress self-discharge. The preparation method provided by this invention allows for independent formation of the electrolyte layer, facilitating large-scale roll-to-roll production and enabling its application in high-energy-density solid-state batteries.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, specifically relating to a solid electrolyte membrane, its preparation method, and its application. Background Technology

[0002] All-solid-state batteries, which use solid electrolytes instead of traditional liquid electrolytes, combine high energy density, high power density, and high safety, and are expected to meet the needs of more life scenarios. They are considered a key direction for future industry development.

[0003] Among developed solid electrolytes, sulfide solid electrolytes have the highest ionic conductivity, exceeding that of commercial electrolytes, and have attracted increasing attention in recent years. However, the dry-powder pressed sulfide solid electrolyte layer is extremely brittle, prone to cracking and even breakage during battery charging and discharging. To avoid battery failure caused by these problems, the layer thickness is typically 0.8-1.2 mm, but this is not conducive to industrialization and also significantly reduces the mass fraction of active materials in the battery system, resulting in lower battery energy density.

[0004] Therefore, sulfide electrolytes need to be prepared into membranes. Currently, the preparation methods for solid electrolyte membranes are mainly divided into dry and wet methods. The wet method involves adding a binder and electrolyte to a solvent to form a slurry, which is then coated and dried to form a membrane. However, the membrane formed by this method has poor mechanical strength, is brittle and prone to falling off, and has a low yield. Summary of the Invention

[0005] To address the issues of weak strength and structural instability in existing solid electrolyte membranes, this invention provides a solid electrolyte membrane that enhances the strength and structural stability of the electrolyte membrane by modifying and grafting active functional groups onto the surface of a substrate (such as nonwoven fabric) and creating a crosslinking network with the binder in the solid electrolyte membrane.

[0006] The first objective of this invention is to provide a solid electrolyte membrane, comprising an electrolyte layer and a substrate layer. The electrolyte layer comprises a solid electrolyte material and a binder. The substrate layer is surface modified and grafted with at least one active functional group, which can polymerize with the binder to form a crosslinked network. The binder is an unsaturated binder.

[0007] In some embodiments of the present invention, the active functional group may be selected from at least one of -OH, -CO-, -COOH, -CO, and -NH2.

[0008] In some embodiments of the present invention, the adhesive is selected from one or more of butadiene rubber, styrene-butadiene rubber (SBR), nitrile rubber (NBR), and styrene-butadiene-styrene block copolymer (SBS).

[0009] The substrate is surface modified by grafting various active functional groups. These functional groups can polymerize with unsaturated bonds (such as double bonds) on the binder to form a cross-linked network, which enhances the chemical bonding between the substrate and the electrolyte membrane, increases the surface roughness and shear strength of the substrate, thereby preparing a tightly structured electrolyte membrane that is not easy to shed, such as a sulfide electrolyte membrane.

[0010] In some embodiments of the present invention, the amount of the binder added is 1-10 wt% of the amount of the electrolyte material, preferably 1-5 wt%.

[0011] In some embodiments of the present invention, the surface modification treatment is selected from at least one of plasma treatment, ozone treatment, chemical reagent oxidation, high-energy radiation treatment, and corona discharge treatment; preferably, the surface modification treatment is selected from plasma treatment and / or ozone treatment.

[0012] In some embodiments of the present invention, the electrolyte layer includes a first electrolyte layer and a second electrolyte layer, and the substrate layer is located between the first electrolyte layer and the second electrolyte layer or near the electrode side. The solid electrolyte membrane provided by the present invention, in which the substrate layer is located between the first electrolyte layer and the second electrolyte layer or near the electrode side, avoids the problem of the substrate easily detaching due to only one side being in contact with the electrolyte layer.

[0013] In some embodiments of the present invention, the substrate layer is selected from at least one of ceramics and nonwoven fabrics.

[0014] In some embodiments of the present invention, the nonwoven fabric is selected from at least one of polypropylene (PP), polyester (PET), nylon (PA), acrylic acid, polyethylene-vinyl acetate (PEVA), ethylene (HDPE), and vinyl (PVC); preferably, the nonwoven fabric web layer includes at least one of polyester (PET), nylon (PA), polyethylene-vinyl acetate (PEVA), and vinyl (PVC).

[0015] In some embodiments of the present invention, the nonwoven fabric includes nonwoven fibers, which are distributed in an irregular manner; preferably, the nonwoven fibers are selected from at least one of meltblown nonwoven fibers, cross-woven fibers, random nonwoven fibers, spun nonwoven fibers, needle-punched nonwoven fibers, ruptured fiber nonwoven fibers, and towed open-fiber nonwoven fibers.

[0016] In some embodiments of the present invention, the nonwoven fibers form a network structure; preferably, the network structure is formed by friction, cohesion or bonding into a sheet or a web.

[0017] In some embodiments of the present invention, the sheet or web is parallel to the electrolyte layer; the sheet or web can reduce the electronic conductivity of the electrolyte membrane, effectively suppress self-discharge, and the independently formed electrolyte layer is easier to produce in large-scale roll-to-roll processes, and can be used in high-energy-density solid-state batteries.

[0018] If the porosity of the sheet-like material or fiber web is too low, it will easily lead to an increase in internal resistance and have a significant impact on ionic conductivity; if the porosity is too high, the mechanical strength of the support will decrease. Therefore, in this invention, the porosity of the sheet-like material or fiber web can be controlled between 35% and 95%; in some embodiments, the porosity of the sheet-like material or fiber web can also be controlled between 75% and 80%, so that the solid electrolyte membrane has high mechanical strength and low internal resistance, achieving a good balance between the two.

[0019] In some embodiments of the present invention, the thickness of the nonwoven fabric can be 5μm-100μm; in some embodiments, the thickness of the nonwoven fabric can also be 8μm-16μm.

[0020] The electrolyte slurry comprises an electrolyte material, a binder, and a solvent. In some embodiments of the present invention, the solid electrolyte material may be at least one of an oxide electrolyte, a polymer electrolyte, and a sulfide electrolyte, preferably a sulfide electrolyte with the highest ionic conductivity.

[0021] In some embodiments of the present invention, the sulfide electrolyte includes Li₂S-P₂S₅, Li 10 GeP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li 10 SnP2S 12 Li6PS5Cl, Li6PS5I, Li6PS5Br and Li 5.5 PS 4.5 C l1.5 At least one of them.

[0022] In some embodiments of the present invention, the particle size range of the sulfide electrolyte powder can be controlled within 1-10 μm, and preferably, the particle size range of the sulfide electrolyte powder is controlled within 1-3 μm.

[0023] In some embodiments of the present invention, the solvent includes one or more of toluene, xylene, anisole, butyl butyrate, n-heptane, pentane, hexane, octane, cyclohexane, cyclohexanone, methylcyclohexanone, chlorobenzene, dichlorobenzene, dichloromethane, methanol, ethanol, isopropanol, diethyl ether, propylene oxide, methyl acetate, ethyl acetate, propyl acetate, acetone, methyl butyl ketone, methyl isobutyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and acetonitrile; preferably, the solvent for dispersing the sulfide electrolyte includes one or more of toluene, xylene, anisole, and n-heptane.

[0024] As a second aspect of the present invention, a method for preparing the aforementioned solid electrolyte membrane is provided, comprising: obtaining a surface-modified substrate by surface modification treatment of a substrate; preparing an electrolyte slurry and coating the electrolyte slurry.

[0025] In existing technologies, a nonwoven fabric / substrate layer is first fixed, and then the slurry is directly and uniformly coated onto the nonwoven fabric / substrate layer in one go, followed by drying to form a film. The corresponding electrolyte membrane, where the nonwoven fabric / substrate only contacts one side of the electrolyte layer or the actual contact area is insufficient, is prone to detachment, or the position of the substrate within the electrolyte layer cannot be controlled. To solve this technical problem, and as a further preferred embodiment of the electrolyte membrane preparation method of this invention, this invention employs a layered coating method to coat the electrolyte slurry. Specifically, a portion of the electrolyte slurry is first coated onto a current collector or PET film and preliminarily dried to obtain a first electrolyte layer. Before the first electrolyte layer is completely dry, a layer of the surface-modified substrate (such as nonwoven fabric) is placed, and then the remaining slurry is coated onto the surface-modified substrate to obtain a second electrolyte layer. By using this method of layering electrolyte slurry, the position of the substrate, sheet, or web in the electrolyte layer can be controlled, for example, in the middle of the first and second electrolyte layers or near the electrode side. This operation avoids the problem of the substrate only contacting one side of the electrolyte layer or the actual contact area being insufficient, which makes it easy to fall off. The resulting electrolyte membrane has a compact structure, is not easy to lose material, and is more robust.

[0026] The aforementioned solid electrolyte membrane can be applied to solid-state batteries. Therefore, as a third aspect of the present invention, a solid-state battery is provided, employing the aforementioned solid electrolyte membrane or the solid electrolyte membrane obtained by the aforementioned preparation method.

[0027] As a fourth aspect of the present invention, an electrical device is provided that employs the aforementioned solid-state battery.

[0028] This invention offers the following advantages: The substrate (e.g., nonwoven fabric) undergoes surface modification and grafting with various active functional groups, such as -OH, -CO-, -COOH, -CO, and -NH2. These functional groups can polymerize with unsaturated bonds (e.g., double bonds) on the binder in the electrolyte slurry to form a cross-linked network, enhancing the chemical bonding between the substrate (e.g., nonwoven fabric) and the slurry. This increases the surface roughness and shear strength of the substrate (e.g., nonwoven fabric), thereby preparing a tightly structured, non-shedding solid electrolyte membrane. When the substrate is nonwoven fabric, the resulting product is a chemically cross-linked flexible solid electrolyte membrane (e.g., a sulfide electrolyte membrane). Compared to traditional wet coating, the introduced surface-modified substrate (e.g., nonwoven fabric) enhances the interaction between the intermediate substrate layer and molecules within the slurry, improving the strength and structural stability of the electrolyte membrane. No additional solvents are used, thus avoiding any impact on the stable structure of the electrolyte. Furthermore, the sheet-like or fiber-like structure with a mesh structure reduces the electronic conductivity of the electrolyte membrane, effectively suppressing self-discharge. Independently formed electrolyte layers are easily manufactured using large-scale roll-to-roll processes and can be used in high-energy-density solid-state batteries. The performance of solid-state batteries and electrical devices based on solid-state electrolyte membranes (such as chemically cross-linked sulfide solid-state electrolyte membranes) provided by this invention is also improved. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is one of the structural schematic diagrams of the solid electrolyte membrane according to the present invention.

[0031] Figure reference numerals: 1: First electrolyte layer, 2: Second electrolyte layer, 3: Nonwoven membrane, 4: Fiber, 5: Cross-linked network formed by polymerization. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0033] Example 1

[0034] This embodiment provides a solid electrolyte membrane, specifically a flexible sulfide electrolyte membrane, such as... Figure 1As shown, it includes a first electrolyte layer 1, a second electrolyte layer 2, and a nonwoven membrane 3 (specifically a PEVA membrane). The nonwoven membrane 3 includes fibers 4, and the surface of the nonwoven membrane 3 is connected by a cross-linked network 5 formed by polymerization with an adhesive.

[0035] The electrolyte membrane provided in this embodiment is prepared as follows:

[0036] Substrate modification treatment: The 8-micron PEVA film was subjected to glow discharge low-temperature plasma surface treatment with N2 as the discharge gas, discharge pressure of 2000 Pa, discharge power of 45 W, and treatment time of 5 min to obtain a surface-aminated PEVA film.

[0037] Prepare a sulfide electrolyte slurry with a certain proportion: Weigh 1.96g of lithium phosphorus sulfide chloride (LPSCl, i.e. Li6PS5Cl) electrolyte powder (powder size 2μm), add 0.04g of SBS and 2g of toluene solution, and mix for half an hour using a double planetary mixer to obtain the slurry.

[0038] Electrolyte slurry coating: A portion of the electrolyte slurry is poured onto the inside of a doctor blade with a gap of 40 μm. The slurry is then coated onto an aluminum foil. After coating, the foil is placed in a drying chamber for a period of time, maintaining an ambient dew point temperature of -50°C to -60°C for 15 minutes, to obtain the first electrolyte layer 1. Subsequently, a surface-aminated PEVA film (i.e., non-woven fabric 3) is placed on the semi-dry slurry layer and placed in a drying chamber for a period of time, maintaining an ambient dew point temperature of -50°C to -60°C for 45 minutes. The internal fibers 4 of the PEVA film are random PEVA fibers with a porosity of 75%.

[0039] The remaining electrolyte slurry was poured onto the upper layer of the aminated PEVA membrane and the inside of the doctor blade, with a doctor blade gap of 80 μm. The remaining electrolyte slurry was then coated onto the surface aminated PEVA membrane to obtain the second electrolyte layer 2. After coating, the membrane was transferred to a 60°C oven for 5 hours to remove the toluene solvent.

[0040] In an inert environment, after the solvent evaporates, the above electrolyte membrane is pressed at 30°C and 10 MPa for 1 minute. A flexible, dense, structurally stable, and uniform chemically cross-linked flexible sulfide electrolyte membrane is formed. The -NH2 on the surface of the PEVA membrane polymerizes with the unsaturated bonds of the binder to form a cross-linked network 5.

[0041] The method for preparing the sulfide electrolyte membrane in this embodiment utilizes a surface-modified nonwoven fabric as a support layer to improve the flexibility of the sulfide electrolyte membrane. Chemical crosslinking is generated by the polymerization reaction between the active functional groups grafted onto the surface of the modified nonwoven fabric and the double bonds of the binder, greatly enhancing the strength and structural stability of the electrolyte membrane and improving the weak mechanical properties and easy material shedding issues of wet-process electrolyte membranes. Simultaneously, it reduces the thickness of the electrolyte membrane, facilitating large-scale production and contributing to the further fabrication of high-energy-density solid-state batteries. The nonwoven fabric used is relatively stable with the sulfide solid electrolyte, minimizing its impact on ionic conductivity while reducing electronic conductivity, suppressing self-discharge, and improving capacity retention. Furthermore, it eliminates the need for additional solvents, thus avoiding any impact on the stable structure of the electrolyte.

[0042] Example 2

[0043] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Embodiment 1. The only difference is that during its preparation process, the discharge power is 65W and the treatment time is 5min during the substrate modification process.

[0044] Example 3

[0045] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Embodiment 1. The only difference is that during its preparation process, the discharge power is 85W and the treatment time is 5min during the substrate modification process.

[0046] Example 4

[0047] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Embodiment 1. The only difference is that during its preparation process, the discharge power is 65W and the treatment time is 8min during the substrate modification process.

[0048] Example 5

[0049] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Embodiment 1. The only difference is that during the substrate modification process, the discharge power is 65W and the processing time is 11min.

[0050] Example 6

[0051] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Embodiment 4, except that PVC is used instead of PEVA in the substrate modification process during its preparation. The PVC has a porosity of 75% and a thickness of 8 μm.

[0052] Example 7

[0053] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Embodiment 4, except that the coating method of the electrolyte slurry is different during its preparation: the surface-aminated PEVA film is placed on a coating machine, and the slurry is poured onto the inside of a doctor blade with a gap of 80 micrometers. After coating, it is transferred to a 60°C oven for 5 hours to remove the toluene solvent. Under inert conditions, after the solvent evaporates, the electrolyte membrane is pressed at 30°C and 10MPa pressure for 1 minute. This forms a flexible, dense, structurally stable, and uniform electrolyte membrane.

[0054] Example 8

[0055] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Example 4, except that the amount of SBS used in its preparation process is 0.02g (1%).

[0056] Example 9

[0057] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Example 4, except that the amount of SBS used in its preparation process is 0.10g (5%).

[0058] Example 10

[0059] This embodiment provides a solid electrolyte membrane, which is basically the same as that in Embodiment 4, except that the PEVA membrane has a porosity of 80% and a thickness of 10 micrometers.

[0060] Comparative Example 1

[0061] This comparative example provides a solid electrolyte membrane, which is basically the same as that in Example 4, except that it is prepared by a wet film formation process without an additional internal support structure: the electrolyte slurry is poured onto the inside of a doctor blade with a gap of 80 micrometers, and the electrolyte slurry is directly coated onto an aluminum foil; after coating, it is transferred to a 60°C oven for 5 hours to remove the toluene solvent; under an inert environment, after the solvent evaporates, the above electrolyte membrane is pressed at 30°C and 10MPa pressure for 1 minute to form a solid electrolyte membrane.

[0062] Comparative Example 2

[0063] This comparative example provides a solid electrolyte membrane, which is basically the same as that in Example 4, except that an unmodified PEVA membrane is used in its preparation process.

[0064] Test case

[0065] Test subjects: Solid electrolyte membranes described in Examples 1-10 and Comparative Examples 1-2.

[0066] Test method:

[0067] (1) Peel strength: Tested using a tensile tester;

[0068] (2) Tensile strength: Tested using a tensile testing machine;

[0069] (3) Electrochemical performance (electronic conductivity, first-cycle efficiency of charge and discharge and capacity retention after 100 cycles): The solid electrolyte membrane, ternary NCM811 positive electrode and silicon-oxygen negative electrode were assembled into a solid soft pack battery, and the long-cycle stability was tested at 0.1C.

[0070] Experimental results: The test results are shown in Table 1 below.

[0071] Table 1

[0072]

[0073] Among them, the electrolyte membrane coated by wet process is prone to cracking and damage, and its mechanical properties (peeling, tensile strength) could not be tested by machine.

[0074] As can be seen from the experimental results in Table 1, the solid electrolyte membrane prepared by the preparation method of the present invention can improve the first-cycle efficiency and the capacity retention rate after 100 cycles when applied to solid-state pouch batteries. Among them, the performance improvement of Example 4 is the most obvious, with a first-cycle efficiency of 79.1% and a capacity retention rate of 90.1% after 100 cycles.

[0075] By comparing the peel strength data of Comparative Example 2 and Example 4, it can be seen that under the same conditions, grafting active functional groups onto the surface of nonwoven fabric can achieve better results: higher peel strength and greater stability. By comparing the peel strength data of Example 7 and Example 4, it can be seen that under the same conditions, using layered coating of electrolyte slurry can achieve better results than direct one-time coating of electrolyte slurry: higher peel strength. Moreover, the position of nonwoven fabric in the electrolyte layer can be controlled, providing a basis for more possible applications.

[0076] The above embodiments are only used to illustrate the preferred solutions of the present invention. Other solutions and combinations involved in the present invention, such as the surface modification treatment method, the selection of electrolyte material and powder size, the selection of nonwoven fabric type and its internal fiber arrangement, the selection of adhesive type, the type of solvent in electrolyte slurry and the type of substrate, etc., will not be described in detail here for the sake of brevity.

[0077] For example, regarding the substrate, any substrate that can be grafted with the above-mentioned active functional groups on its surface through surface modification treatment, such as non-woven fabric or ceramic substrate, can be used with the inventive concept of the electrolyte membrane preparation method of the present invention to modify the surface of the substrate to graft active functional groups for the preparation of solid electrolyte membrane. Therefore, the non-woven fabric listed in the present invention is only one embodiment for the preparation of flexible solid electrolyte membrane, and the present invention does not list other substrates one by one.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solid electrolyte membrane, characterized in that, It includes an electrolyte layer and a substrate layer. The electrolyte layer includes a solid electrolyte material and a binder. The substrate layer is surface modified and grafted with at least one active functional group. The active functional group can polymerize with the binder to form a cross-linked network. The adhesive is an unsaturated adhesive; the active functional group includes at least one of -OH, -CO-, -COOH, -CO, and -NH2; the adhesive is selected from at least one of butadiene rubber, styrene-butadiene rubber, nitrile rubber, and styrene-butadiene-styrene block copolymer; the amount of adhesive added is 1-10 wt% of the amount of the electrolyte material; the electrolyte layer includes a first electrolyte layer and a second electrolyte layer, and the substrate layer is located between the first electrolyte layer and the second electrolyte layer.

2. The solid electrolyte membrane according to claim 1, characterized in that, The amount of binder added is 1-5 wt% of the amount of electrolyte material used.

3. The solid electrolyte membrane according to claim 1 or 2, characterized in that, The surface modification treatment is selected from at least one of plasma treatment, ozone treatment, chemical reagent oxidation, high-energy radiation treatment, and corona discharge treatment.

4. The solid electrolyte membrane according to claim 3, characterized in that, The surface modification treatment is selected from plasma treatment and / or ozone treatment.

5. The solid electrolyte membrane according to claim 1 or 2, characterized in that, The substrate layer is selected from at least one of ceramics and non-woven fabrics.

6. The solid electrolyte membrane according to claim 5, characterized in that, The nonwoven fabric is selected from one or more of polypropylene, polyester, nylon, acrylic acid, polyethylene-vinyl acetate, ethylene, and vinyl.

7. The solid electrolyte membrane according to claim 6, characterized in that, The nonwoven fabric is selected from one or more of polyester, nylon, polyethylene-vinyl acetate and vinyl.

8. The solid electrolyte membrane according to claim 5, characterized in that, The nonwoven fabric includes nonwoven fibers, which are distributed in an irregular direction.

9. The solid electrolyte membrane according to claim 8, characterized in that, The nonwoven fibers include at least one of meltblown nonwoven fibers, cross-woven fibers, random nonwoven fibers, spun nonwoven fibers, needle-punched nonwoven fibers, ruptured fiber nonwoven fibers, and towed open-fiber nonwoven fibers.

10. The solid electrolyte membrane according to claim 8, characterized in that, The nonwoven fibers form a network structure.

11. The solid electrolyte membrane according to claim 10, characterized in that, The network structure is selected from at least one of fiber webs formed by friction, cohesion, or bonding into sheet-like structures.

12. The solid electrolyte membrane according to claim 11, characterized in that, The porosity of the sheet or fiber web is 35%-95%.

13. The solid electrolyte membrane according to claim 12, characterized in that, The porosity of the sheet or fiber web is 75%-80%.

14. The solid electrolyte membrane according to claim 11, characterized in that, The sheet-like material or fiber web is parallel to the electrolyte layer.

15. The solid electrolyte membrane according to claim 5, characterized in that, The thickness of the nonwoven fabric is 5μm-100μm.

16. The solid electrolyte membrane according to claim 15, characterized in that, The thickness of the nonwoven fabric is 8μm-16μm.

17. The solid electrolyte membrane according to claim 1 or 2, characterized in that, The solid electrolyte material is selected from at least one of oxide electrolytes, polymer electrolytes, and sulfide electrolytes.

18. The solid electrolyte membrane according to claim 17, characterized in that, The sulfide electrolyte is selected from Li2S-P2S5, Li 10 GeP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 C l0.3 Li 10 SnP2S 12 Li6PS5Cl, Li6PS5I, Li6PS5Br and Li 5.5 PS 4.5 Cl 1.5 One, two, or more of them.

19. The solid electrolyte membrane according to claim 17, characterized in that, The powder particle size of the sulfide electrolyte is 1-10 μm.

20. The solid electrolyte membrane according to claim 19, characterized in that, The powder particle size of the sulfide electrolyte is 1-3 μm.

21. The solid electrolyte membrane according to claim 17, characterized in that, The preparation process of the electrolyte layer also includes a solvent, which is selected from one or more of the following: toluene, xylene, anisole, butyl butyrate, n-heptane, pentane, hexane, octane, cyclohexane, cyclohexanone, methylcyclohexanone, chlorobenzene, dichlorobenzene, dichloromethane, methanol, ethanol, isopropanol, diethyl ether, propylene oxide, methyl acetate, ethyl acetate, propyl acetate, acetone, methyl butyl ketone, methyl isobutyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and acetonitrile.

22. The solid electrolyte membrane according to claim 21, characterized in that, The solvent is selected from one or more of toluene, xylene, anisole, and n-heptane.

23. The method for preparing the solid electrolyte membrane according to any one of claims 1-22, characterized in that, include: A surface-modified substrate is obtained by surface modification treatment of the substrate; Prepare an electrolyte slurry and coat the electrolyte slurry.

24. The method for preparing a solid electrolyte membrane according to claim 23, characterized in that, When coating the electrolyte slurry, a layered coating method is adopted: first, a portion of the electrolyte slurry is coated on the current collector or PET film and preliminarily dried to obtain a first electrolyte layer; then, a layer of the substrate is placed on the first electrolyte layer; then, the remaining slurry is coated on the substrate and dried to obtain the solid electrolyte membrane.

25. The method for preparing a solid electrolyte membrane according to claim 24, characterized in that, The substrate is placed while the first electrolyte layer is not completely dry.

26. A solid-state battery, characterized in that, Includes the solid electrolyte membrane according to any one of claims 1-22 and / or the solid electrolyte membrane obtained by the preparation method according to any one of claims 23-25.

27. An electrical appliance, characterized in that, Including the solid-state battery as described in claim 26.

Images