Solid electrolyte membrane, preparation method and lithium ion battery

Abstract

The invention discloses a solid electrolyte membrane, a preparation method thereof and a lithium ion battery, and relates to the technical field of batteries. According to the embodiment of the invention, the polymer membrane is arranged on at least one side of the electrolyte membrane body; the polymer film comprises poly (vinylidene fluoride-trifluorochlor oethylene) and lithium salt dispersed in the poly (vinylidene fluoride-trifluorochlor oethylene), and the mass ratio of the poly (vinylidene fluoride-trifluorochlor oethylene) to the lithium salt is (0.5-2): (0.5-2). Therefore, the battery with the solid electrolyte membrane provided by the embodiment of the invention has relatively low impedance, relatively high ionic conductivity and relatively high cycle performance.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular, to a solid electrolyte membrane, a preparation method thereof, and a lithium ion battery. Background Art

[0002] Currently, due to advantages such as long cycle life and high energy density, lithium ion batteries have become one of the most important energy storage devices in people's daily lives. In recent years, with the rapid development of electric vehicles, higher requirements have been put forward for the energy density and safety performance of batteries. All-solid-state lithium metal batteries replace the flammable liquid electrolyte with a solid electrolyte, and at the same time use metallic lithium with a higher theoretical specific capacity as the negative electrode, having advantages such as high safety and high energy density. Therefore, it is of great significance to study all-solid-state lithium metal batteries.

[0003] In the field of all-solid-state batteries, the interfacial contact between the electrolyte and the lithium negative electrode has always been a matter of great concern. Such non-close contact will lead to a series of serious consequences, one of which is to accelerate the growth of lithium dendrites. The appearance of lithium dendrites may further damage the electrolyte membrane, and even cause short circuit between the positive and negative electrodes, ultimately resulting in poor cycle performance of the battery, or even causing battery short circuit, bringing serious safety hazards. Summary of the Invention

[0004] In view of this, in the first aspect of the present application, a solid electrolyte membrane is provided. The solid electrolyte membrane includes an electrolyte membrane body arranged in a stacked manner and a polymer membrane provided on at least one side of the electrolyte membrane body; wherein, the polymer membrane includes poly(vinylidene fluoride-trifluorochloroethylene) and a lithium salt dispersed in the poly(vinylidene fluoride-trifluorochloroethylene). Calculated by mass ratio, poly(vinylidene fluoride-trifluorochloroethylene): lithium salt is (0.5 to 2): (0.5 to 2).

[0005] In some embodiments of the present application, the polymer membrane is adhered to the electrolyte membrane body through the poly(vinylidene fluoride-trifluorochloroethylene); and / or the polymer membrane further includes a solvent; and / or the electrolyte membrane body is an alkaline membrane; and / or the polymer membrane further includes an ionic liquid. Calculated by mass ratio, the poly(vinylidene fluoride-trifluorochloroethylene): the lithium salt: the ionic liquid is (0.5 to 2): (0.5 to 2): (0.5 to 2.5).

[0006] In some embodiments of the present application, the poly(vinylidene fluoride-trifluorochloroethylene): the lithium salt: the ionic liquid is (0.9 to 1.1): (0.9 to 1.1): (0.9 to 2.5); and / or the mass content of the solvent in the polymer membrane is 5% to 10%.

[0007] In some embodiments of the present application, the polymer membrane and the electrolyte membrane body form an integral structure.

[0008] In some embodiments of the present application, the solvent is an organic solvent.

[0009] In some embodiments of the present application, the thickness of the polymer membrane is 5 μm to 10 μm.

[0010] In some embodiments of the present application, the lithium salt is selected from one or more of LiCl, LiBr, LiI, LiFSI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 , LiBOB, LiCF3SO3, LiTFSI, LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI.

[0011] In some embodiments of the present application, the ionic liquid contains an organic cation and an organic or inorganic anion; the organic cation includes at least one of a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation with a pyrroline skeleton, a cation with a pyrrole skeleton, an imidazolium cation, a tetrahydropyrimidinium cation, a dihydropyrimidinium cation, a pyrazolium cation, a pyrazolinium cation, a tetraalkylammonium cation, a trialkylsulfonium cation, or a tetraalkylphosphonium cation; and / or the organic or inorganic anion includes F - , Cl - , Br - , I - , NO3 - , (CN)2N - , BF4 - , ClO4 - , RSO3 - , RCOO - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , (C2F5SO2)2N - , (CF3SO3)2N - , (CF3SO2)(CF3CO)N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH -, (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3COO - , C3F7COO - , CF3SO3 - , C4F9SO3 - at least one of

[0012] The second aspect of the present application provides a method for preparing a solid electrolyte membrane for preparing the solid electrolyte membrane. The preparation method includes the following steps: Provide a mixed solution; wherein the mixed solution includes poly(vinylidene fluoride-trifluorochloroethylene), a lithium salt, and a solvent. Exemplarily, the mixed solution is prepared by dissolving poly(vinylidene fluoride-trifluorochloroethylene) and a lithium salt in a solvent.

[0013] Coat the mixed solution on a substrate; Obtain a polymer membrane after removing part of the solvent; Stack the polymer membrane on at least one side of the electrolyte membrane body. Exemplarily, lay the electrolyte membrane body on the polymer membrane and obtain a solid electrolyte membrane through heat treatment.

[0014] In some embodiments of the present application, the heat treatment includes: keeping warm in an oven at a temperature of 40°C to 70°C for 2 hours to 10 hours. For example, place the substrate (such as a glass substrate) containing the electrolyte membrane body in the oven and keep warm at a temperature of 40°C to 70°C for 2H to 10H.

[0015] In the step of obtaining a polymer membrane after removing part of the solvent, part of the solvent is removed by heating, and the mass percentage of the solvent in the polymer membrane obtained after removing part of the solvent is 40% to 60%.

[0016] In the step of obtaining a solid electrolyte membrane through heat treatment, the mass percentage of the solvent in the polymer membrane in the solid electrolyte membrane is 5% to 10%, that is, after heat treatment, the mass percentage of the solvent in the polymer membrane to the mass of the polymer membrane is 5% to 10%.

[0017] The step of providing the mixed solution includes: adding an ionic liquid and a lithium salt to a solvent and mixing and stirring evenly to obtain a mixed solution.

[0018] In some embodiments of the present application, the coating thickness is 5 μm to 10 μm; and / or The lithium salt is selected from one or more of LiCl, LiBr, LiI, LiFSI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 、LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiCH3SO3, LiCF3CO2, LiCH3CO2 and LiBETI (LiN(SO2CF2CF3)2); and / or The ionic liquid contains an organic cation and an organic or inorganic anion; the organic cation may include at least one of a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation with a pyrroline skeleton, a cation with a pyrrole skeleton, an imidazolium cation, a tetrahydropyrimidinium cation, a dihydropyrimidinium cation, a pyrazolium cation, a pyrazolinium cation, a tetraalkylammonium cation, a trialkylsulfonium cation or a tetraalkylphosphonium cation; and / or The organic or inorganic anion may include F - 、Cl - 、Br - 、I - 、NO3 - 、(CN)2N - 、BF4 - 、ClO4 - 、RSO3 - 、RCOO - 、PF6 - 、(CF3)2PF4 - 、(CF3)3PF3 - 、(CF3)4PF2 - 、(CF3)5PF - 、(CF3)6P - 、(C2F5SO2)2N - 、(CF3SO3)2N - 、(CF3SO2)(CF3CO)N - 、CF3CF2(CF3)2CO - 、(CF3SO2)2CH - 、(SF5)3C - 、(CF3SO2)3C - 、CF3(CF2)7SO3 - 、CF3COO - 、C3F7COO - 、CF3SO3 - 、C4F9SO3 - ; at least one of them; The mass ratio of the poly(vinylidene fluoride-chlorotrifluoroethylene) to the mixed solution is 10% to 20%; and / or The mass ratio of the solvent to the mixed solution is 40% to 60%.

[0019] The third aspect of the present application provides a lithium-ion battery, which includes a positive electrode, a negative electrode, and the solid electrolyte membrane described above or the solid electrolyte membrane obtained by the preparation method described above.

[0020] Beneficial effects: In the embodiment of the present application, a polymer membrane is provided on at least one side of the electrolyte membrane body. The polymer membrane includes poly(vinylidene fluoride-chlorotrifluoroethylene) and a lithium salt dispersed in the poly(vinylidene fluoride-chlorotrifluoroethylene). Calculated by mass ratio, poly(vinylidene fluoride-chlorotrifluoroethylene):lithium salt is (0.5 to 2):(0.5 to 2), so that the battery with the solid electrolyte membrane in the embodiment of the present application has a lower impedance, a higher ionic conductivity, and the battery with this solid electrolyte membrane has a higher cycle performance. Description of the drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0022] Figure 1 It is an electron microscope image of the cross-section of the solid electrolyte membrane obtained in Example 1 of the present application magnified 1000 times; Figure 2 It is an electron microscope image of the cross-section of the solid electrolyte membrane obtained in Example 1 of the present application magnified 2000 times; Figure 3 It is an impedance test chart of the battery assembled with the solid electrolyte membrane obtained in Example 1 of the present application; Figure 4 It is an impedance test chart of the battery assembled with the solid electrolyte membrane obtained in Comparative Example 4 of the present application. Detailed implementation manners

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] In the present application, unless otherwise stated, the orientation terms such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings; and "inner" and "outer" refer to the outline of the device. In addition, in the description of the present application, the term "comprising" means "including but not limited to". The use of terms such as first, second, and third is only for marking purposes and does not impose a numerical requirement or establish an order.

[0026] In the present application, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, or B exists alone. Wherein A and B may be singular or plural.

[0027] In the present application, "at least one" means one or more, and "a plurality" means two or more. "One or more", "at least one of the following (items)", or similar expressions refer to any combination of these items, including any combination of single (item) or plural (items). For example, "at least one of (item) a, b, or c", or, "at least one of (item) a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0028] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0029] Currently, due to its advantages such as long cycle life and high energy density, lithium-ion batteries have become one of the most important energy storage devices in people's daily lives. In recent years, with the rapid development of electric vehicles, higher requirements have been put forward for the energy density and safety performance of batteries. All-solid-state lithium-metal batteries replace the flammable liquid electrolyte with a solid electrolyte and use metallic lithium with a higher theoretical specific capacity as the negative electrode, having advantages such as high safety and high energy density. Therefore, it is of great significance to study all-solid-state lithium-metal batteries.

[0030] In the field of all-solid-state batteries, the interfacial contact between the electrolyte and the lithium negative electrode has always been a matter of great concern. Such poor contact will lead to a series of serious consequences, one of which is the accelerated growth of lithium dendrites. The appearance of lithium dendrites may further damage the electrolyte membrane and even cause short-circuiting between the positive and negative electrodes, ultimately resulting in poor cycle performance of the battery or even battery short-circuiting, posing a serious safety hazard.

[0031] In view of this, in the first aspect of the embodiments of the present application, a solid electrolyte membrane is provided. The solid electrolyte membrane includes an electrolyte membrane body and a polymer membrane arranged in a stacked manner, and the polymer membrane is disposed on at least one side of the electrolyte membrane body; wherein, the polymer membrane includes poly(vinylidene fluoride-trifluoroethylene) and a lithium salt dispersed in the poly(vinylidene fluoride-trifluoroethylene). Calculated by mass ratio, poly(vinylidene fluoride-trifluoroethylene): lithium salt is (0.5 to 2): (0.5 to 2).

[0032] In the embodiments of the present application, by providing a polymer membrane on at least one side of the electrolyte membrane body, and the polymer membrane includes poly(vinylidene fluoride-trifluoroethylene) and a lithium salt dispersed in the poly(vinylidene fluoride-trifluoroethylene), and calculated by mass ratio, poly(vinylidene fluoride-trifluoroethylene): lithium salt is (0.5 to 2): (0.5 to 2), the battery having the solid electrolyte membrane in the embodiments of the present application has lower impedance and cycle performance.

[0033] When the solid electrolyte membrane in the embodiments of the present application is used in a lithium metal battery, a polymer membrane can be disposed between the electrolyte membrane body and the lithium negative electrode. The polymer can enhance the contact between the electrolyte membrane body and the lithium negative electrode, making it more intimate, thereby effectively reducing the possibility of lithium dendrite growth. At the same time, this polymer membrane can also prevent the formation of lithium dendrites, and further contribute to the formation of a stable and good solid electrolyte interface layer (SEI), thus improving the safety of the battery. Moreover, the polymer membrane includes a certain content of lithium salt, so that the battery with the solid electrolyte membrane in the embodiments of the present application has a lower impedance and cycling performance.

[0034] In addition, the polymer membrane includes poly(vinylidene fluoride-trifluorochloroethylene), making the polymer membrane have excellent chemical corrosion resistance and abrasion resistance.

[0035] Exemplarily, calculated by mass fraction, poly(vinylidene fluoride-trifluorochloroethylene) in the preparation raw materials of the polymer membrane can be 0.5 part, 1 part, 1.5 parts, and 2 parts. Correspondingly, the lithium salt in the preparation raw materials of the polymer membrane can be 0.5 part, 1 part, 1.5 parts, and 2 parts.

[0036] In some embodiments of the present application, the molecular weight of poly(vinylidene fluoride-trifluorochloroethylene) is 400,000 to 500,000. Exemplarily, the molecular weight of the poly(vinylidene fluoride-trifluorochloroethylene) is about 450,000.

[0037] In some embodiments of the present application, the mass content of vinylidene fluoride in poly(vinylidene fluoride-trifluorochloroethylene) is 75% to 85%, and the mass content of trifluorochloroethylene is 15% to 25%. Exemplarily, the mass content of vinylidene fluoride in poly(vinylidene fluoride-trifluorochloroethylene) is about 80%, and the mass content of trifluorochloroethylene is about 20%.

[0038] In some embodiments of the present application, the polymer membrane is bonded to the electrolyte membrane body through the poly(vinylidene fluoride-trifluorochloroethylene), which can also be understood as the polymer membrane is bonded to the electrolyte membrane body through its own adhesion force. Further, the polymer membrane and the electrolyte membrane body are bonded through the poly(vinylidene fluoride-trifluorochloroethylene) to form an integral structure.

[0039] Exemplarily, the polymer membrane further includes a solvent, which can also be understood as the polymer membrane is a wet membrane. It should be noted that a polymer wet membrane refers to a membrane with a certain amount of solvent. The polymer wet membrane is softer and has strong adhesion performance, and it can be bonded to the electrolyte membrane body through its own adhesion force. Exemplarily, the mass content of the solvent in the polymer membrane is 5% to 10%. For example, the mass content of the solvent in the polymer membrane is 5%, 6%, 7%, 8%, 9%, 10%, and the range values between any two of the above values.

[0040] Specifically, a polymer wet film with a relatively high solvent content can be prepared first. Then, after laying the polymer wet film on the electrolyte membrane body, a part of the solvent in the wet film is removed to obtain a polymer film. In this way, a polymer film can be formed by in-situ reaction of the polymer wet film with a relatively high solvent content on the electrolyte membrane body, so that the electrolyte membrane body and the interface of the polymer film are better combined and the interface connection is tighter. This is beneficial to further making the battery with the solid electrolyte membrane in the embodiments of the present application have lower impedance and cycling performance.

[0041] Furthermore, the polymer film and the electrolyte membrane body form an integral structure. For example, the polymer film is formed in-situ on the electrolyte membrane body, so that the polymer film and the electrolyte membrane body form an integral structure. In this way, it is beneficial to further make the battery with the solid electrolyte membrane in the embodiments of the present application have lower impedance and cycling performance.

[0042] Furthermore, the thickness of the polymer film is 5um - 10um. Exemplarily, the thickness of the polymer film is 5um, 6um, 7um, 8um, 9um, 10um, and the range values between any two of the above values. It should be noted that if the thickness of the polymer film is too low, for example, less than 5um, it is easy to cause difficulties in the process of peeling off the wet film in the previous process of preparing the polymer film. If the thickness is too large, for example, greater than 10um, it is easy to cause a relatively large volume of the solid electrolyte membrane.

[0043] Specifically, the solvent in the polymer film can be an organic solvent such as DMF, NMP, TFE, acetone, etc.

[0044] In some embodiments of the present application, the electrolyte membrane body is an alkaline membrane. Exemplarily, the components of the electrolyte membrane body are LLZO (lithium lanthanum zirconium oxide) and PTFE (polytetrafluoroethylene). By mass, LLZO accounts for 80% - 99.9% of the electrolyte membrane body, and PTFE accounts for 20% - 0.01% of the electrolyte membrane body. It should be noted that since the electrolyte membrane body is an alkaline membrane, poly(vinylidene fluoride-trifluoroethylene) can undergo a de-F (fluorine) reaction in an alkaline environment, thereby increasing the adhesion of the polymer film and the bonding performance between the polymer film and the electrolyte membrane body at the interface, which is beneficial to further increasing the ionic conductivity of the solid electrolyte membrane in the present application and the performance of the battery with this solid electrolyte membrane.

[0045] In some embodiments of the present application, the surface of the electrolyte membrane body that is bonded to the polymer film has a plurality of micropores.

[0046] Further, the porosity of the electrolyte membrane body is 3% to 5%. Exemplarily, the porosity of the electrolyte membrane body is 3%, 3.5%, 4%, 4.5%, 5%, and the range values between any two of the above numerical values.

[0047] In some embodiments of the present application, the raw materials for preparing the polymer membrane further include an ionic liquid. Calculated by mass ratio, poly(vinylidene fluoride-trifluorochloroethylene): lithium salt: ionic liquid is (0.5 to 2): (0.5 to 2): (0.5 to 2.5). Further, poly(vinylidene fluoride-trifluorochloroethylene): lithium salt: ionic liquid is (0.9 to 1.1): (0.9 to 1.1): (0.9 to 2.5). In this embodiment, adding a certain content of ionic liquid to the polymer membrane is beneficial to further reduce the impedance of the battery and improve the cycling performance of the battery.

[0048] It should be noted that adding a lithium salt to the polymer membrane in the present application is beneficial to improve the ionic conductivity of the solid electrolyte membrane (or polymer membrane), and the specific type of the lithium salt is not limited.

[0049] In some embodiments of the present application, the lithium salt is selected from one or more of LiCl, LiBr, LiI, LiFSI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 , LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI (LiN(SO2CF2CF3)2).

[0050] Specifically, in some embodiments of the present application, the lithium salt is selected from lithium bis(fluorosulfonyl)imide (LiFSI). For another example, in some other embodiments of the present application, the lithium salt is selected from lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2). For another example, in some other embodiments of the present application, the lithium salt is selected from lithium perchlorate (LiClO4). For another example, in some other embodiments of the present application, the lithium salt is selected from lithium bis(fluorosulfonyl)imide (LiFSI) and lithium perchlorate (LiClO4). It should be noted that compared with the lithium salt selected from lithium perchlorate (LiClO4), the lithium salt selected from lithium bis(fluorosulfonyl)imide (LiFSI) and / or lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2) has higher safety performance.

[0051] It should be noted that an ionic liquid is a compound containing an organic cation and an organic or inorganic anion. In this application, adding an ionic liquid to the polymer membrane is beneficial to improving the stability and electrochemical performance of the solid electrolyte membrane, and is beneficial to enhancing the safety and cycle performance of the battery, and is beneficial to reducing the impedance of the battery. There is no particular limitation on the types of cations and anions contained in the ionic liquid.

[0052] For example, the cations contained in the ionic liquid may include at least one of pyridinium cations, piperidinium cations, pyrrolidinium cations, cations with a pyrroline backbone, cations with a pyrrole backbone, imidazolium cations, tetrahydropyrimidinium cations, dihydropyrimidinium cations, pyrazolium cations, pyrazolinium cations, tetraalkylammonium cations, trialkylsulfonium cations or tetraalkylphosphonium cations.

[0053] The anions contained in the ionic liquid may include F - , Cl - , Br - , I - , NO3 - , (CN)2N - , BF4 - , ClO4 - , RSO3 - (wherein, R is an alkyl group or a phenyl group having 1 to 9 carbon atoms), RCOO - (wherein, R is an alkyl group or a phenyl group having 1 to 9 carbon atoms), PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , (C2F5SO2)2N - , (CF3SO3)2N - , (CF3SO2)(CF3CO)N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3COO - , C3F7COO - , CF3SO3 - or C4F9SO3 - .

[0054] Specifically, the ionic liquid may include, but is not limited to, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-2,3-dimethylimidazolium chloride (BMMImCl), Pyr13TFSI, and Pyr14TFSI.

[0055] In some embodiments of the present application, the electrolyte membrane body includes at least one of doped or undoped LLZO oxide ceramic solid electrolyte, doped or undoped sulfide solid electrolyte, and doped or undoped halide solid electrolyte.

[0056] The second aspect of the embodiments of the present application provides a method for preparing a solid electrolyte membrane, including the following steps: S10 Provide a mixed solution; wherein, the mixed solution includes poly(vinylidene fluoride-trifluorochloroethylene), a lithium salt, and a solvent, and the poly(vinylidene fluoride-trifluorochloroethylene) and the lithium salt are dissolved in the solvent.

[0057] Specifically, the ionic liquid and the lithium salt are added to the solvent and mixed and stirred evenly to obtain a mixed solution.

[0058] Exemplarily, the mass ratio of poly(vinylidene fluoride-trifluorochloroethylene) in the mixed solution is 10% to 20%. It can be understood that if the mass ratio of poly(vinylidene fluoride-trifluorochloroethylene) to the mixed solution is too low, it is easy to cause the solution system to fail to form a complete film during scraping or the formed film to be uneven and unable to be peeled off from the glass plate. If the mass ratio of poly(vinylidene fluoride-trifluorochloroethylene) to the mixed solution is too high, it is easy to cause the poly(vinylidene fluoride-trifluorochloroethylene) not to be completely dissolved in the solvent.

[0059] It should be noted that the stirring speed and stirring time are not limited, and it is only necessary to enable the ionic liquid and the lithium salt to be dissolved in the solvent. Exemplarily, this process can be carried out at room temperature.

[0060] S20 Coat the mixed solution on a substrate and remove part of the solvent to obtain a polymer wet film.

[0061] It should be noted that to avoid chemical reactions between the substrate and the polymer wet film and facilitate the separation of the polymer film from the substrate in subsequent processes, the substrate can be a glass substrate. Of course, in some other embodiments of the present application, the substrate can also be other substrates (such as a silicon substrate), which is not limited herein. Unless otherwise specified below, the glass substrate will be taken as an example for illustration.

[0062] Specifically, the mixed solution can be coated on the glass substrate through a coater, and then the glass substrate coated with the mixed solution is placed in an oven to remove part of the solvent to obtain a polymer wet film.

[0063] In some embodiments of the present application, the glass substrate coated with the mixed solution is placed in an oven and kept warm at a temperature of 50°C to 80°C for 2 minutes to 30 minutes.

[0064] Exemplarily, the mass ratio of the solvent in the polymer wet film is 40% to 60%. It should be noted that if the mass ratio of the solvent is too low (for example, less than 40%), it is likely to result in poor adhesion, and the polymer wet film and the electrolyte membrane body are prone to separation during the subsequent heat treatment to remove part of the solvent. If the mass ratio of the solvent is too high (for example, higher than 60%), the reaction between the polymer wet film and the electrolyte membrane body is too intense, affecting the overall performance of the membrane subsequently.

[0065] Specifically, the glass substrate coated with the mixed solution is placed in an oven at 60°C and kept warm for 5 minutes.

[0066] S30 Lay the electrolyte membrane body on the polymer wet film and obtain a solid electrolyte membrane through heat treatment.

[0067] Specifically, after heat treatment, the polymer wet film loses part of the solvent and forms a polymer film, and the electrolyte membrane body and the polymer film form an integral structure.

[0068] In some embodiments of the present application, the substrate containing the electrolyte membrane body (such as a glass substrate) is placed in an oven and kept warm at a temperature of 50°C to 80°C for 2H to 10H. It should be noted that the mass percentage content of the solvent in the polymer film obtained after this step is 5% to 10%. In this way, the solvent can basically exist in the polymer film in a complex state, which is beneficial to further improving the performance of the battery with this solid electrolyte membrane.

[0069] Specifically, the glass substrate coated with the mixed solution is placed in an oven at 60 degrees and kept warm for 4H.

[0070] It should be noted that the solid electrolyte membrane prepared by the preparation process of the embodiments of the present application is beneficial to increasing the contact area and the bonding force at the interface between the polymer film and the electrolyte membrane body, beneficial to avoiding the problem of poor contact between the polymer film and the solid electrolyte membrane body, and enabling the battery with the solid electrolyte membrane in the embodiments of the present application to have a lower impedance and cycle performance.

[0071] It should be noted that the solvent in the present application is not limited, and it only needs to satisfy that it can dissolve poly(vinylidene fluoride-trifluorochloroethylene) and lithium salt, and the solvent is easy to remove after film formation. Exemplarily, the solvent includes but is not limited to N,N-dimethylformamide.

[0072] In some embodiments of the present application, the thickness of the polymer wet film is 5μm to 10μm.

[0073] In some embodiments of the present application, the polymer membrane further includes an ionic liquid. Calculated by mass ratio, poly(vinylidene fluoride-trifluorochloroethylene):lithium salt:ionic liquid is (0.5 to 2):(0.5 to 2):(0.5 to 2.5). Further, poly(vinylidene fluoride-trifluorochloroethylene):lithium salt:ionic liquid is (0.9 to 1.1):(0.9 to 1.1):(0.9 to 2.5). In this embodiment, adding a certain content of ionic liquid to the polymer membrane is beneficial to further reduce the impedance of the battery and improve the cycle performance of the battery.

[0074] It should be noted that adding a lithium salt to the polymer membrane in the present application is beneficial to improve the ionic conductivity of the solid electrolyte membrane, and the specific type of the lithium salt is not limited.

[0075] In some embodiments of the present application, the lithium salt is selected from LiCl, LiBr, LiI, LiFSI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 , LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiCH3SO3, LiCF3CO2, LiCH3CO2 and LiBETI (LiN(SO2CF2CF3)2), or one or more thereof.

[0076] Specifically, in some embodiments of the present application, the lithium salt is selected from lithium bis(fluorosulfonyl)imide (LiFSI). For another example, in some other embodiments of the present application, the lithium salt is selected from lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2). For another example, in some other embodiments of the present application, the lithium salt is selected from lithium perchlorate (LiClO4). For another example, in some other embodiments of the present application, the lithium salt is selected from lithium bis(fluorosulfonyl)imide (LiFSI) and lithium perchlorate (LiClO4). It should be noted that compared with the lithium salt selected from lithium perchlorate (LiClO4), the lithium salt selected from lithium bis(fluorosulfonyl)imide (LiFSI) and / or lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2) has higher safety performance.

[0077] It should be noted that the ionic liquid is a compound containing an organic cation and an organic or inorganic anion. Adding an ionic liquid to the polymer membrane in the present application is beneficial to improve the ionic conductivity of the solid electrolyte membrane, is beneficial to improve the safety and cycle performance of the battery, and is beneficial to reduce the impedance of the battery. The types of cations and anions contained in the ionic liquid are not particularly limited.

[0078] For example, the cations contained in the ionic liquid may include pyridinium cations, piperidinium cations, pyrrolidinium cations, cations having a pyrroline skeleton, cations having a pyrrole skeleton, imidazolium cations, tetrahydropyrimidinium cations, dihydropyrimidinium cations, pyrazolium cations, pyrazolinium cations, tetraalkylammonium cations, trialkylsulfonium cations or tetraalkylphosphonium cations.

[0079] The anions contained in the ionic liquid may include F - , Cl - , Br - , I - , NO3 - , (CN)2N - , BF4 - , ClO4 - , RSO3 - (wherein, R is an alkyl group having 1 to 9 carbon atoms or a phenyl group), RCOO - (wherein, R is an alkyl group having 1 to 9 carbon atoms or a phenyl group), PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , (C2F5SO2)2N - , (CF3SO3)2N - , (CF3SO2)(CF3CO)N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3COO - , C3F7COO - , CF3SO3 - or C4F9SO3 - .

[0080] Specifically, the ionic liquid may include, but is not limited to, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-2,3-dimethylimidazolium chloride (BMMImCl), Pyr13TFSI, Pyr14TFSI, EMIMTFSI.

[0081] In some embodiments of the present application, the electrolyte membrane body includes at least one of doped or undoped LLZO oxide ceramic solid electrolyte, doped or undoped sulfide solid electrolyte, and doped or undoped halide solid electrolyte.

[0082] For ease of understanding, the solid electrolyte membrane in the present application will be further described below in conjunction with specific embodiments and experimental test results.

[0083] Example 1 (1) Preparation of the mixed solution: P(VDF-TrFE) (poly(vinylidene fluoride-trifluorochloroethylene), with a weight-average molecular weight of about 450,000 and a mass ratio of vinylidene fluoride to trifluorochloroethylene of about 4:1), 1-butyl-2,3-dimethylimidazolium chloride, and lithium bis(fluorosulfonyl)imide were mixed in a mass ratio of 1:1:1, and then added to N,N-dimethylformamide and stirred at room temperature for 12 hours to form a uniform mixed solution.

[0084] (2) Preparation of the polymer membrane: The mixed solution obtained in step (1) was coated on a glass substrate by a coater and placed in an oven at 60 °C for a certain period of time to obtain a polymer wet membrane with a thickness of 10 μm and a solvent content of 50% in the polymer wet membrane.

[0085] (3) The electrolyte membrane body was evenly laid on the polymer wet membrane, and then the glass substrate with the electrolyte membrane was placed in an oven at 60 °C for 4 h to obtain an electrolyte membrane with a thickness of about 50 μm, and the mass content of the solvent in the polymer membrane was 5% to 10%. The electron micrograph of a cross-section of the electrolyte membrane at a certain location is as Figure 1 and Figure 2 shown.

[0086] Example 2 The difference from Example 1 is that in the preparation step of the mixed solution, 1-butyl-2,3-dimethylimidazolium chloride was not added. Specifically as follows: (1) Preparation of the mixed solution: P(VDF-TrFE) and lithium bis(fluorosulfonyl)imide were mixed in a mass ratio of 1:1, and then added to N,N-dimethylformamide and stirred at room temperature for 12 hours to form a uniform mixed solution.

[0087] Example 3 The difference from Example 1 is that in the preparation step of the mixed solution, the mass ratio of P(VDF-TrFE), 1-butyl-2,3-dimethylimidazolium chloride, and lithium bis(fluorosulfonyl)imide is 1:2:1. Specifically as follows: (1) Preparation of the mixed solution: P(VDF-TrFE), 1-butyl-2,3-dimethylimidazolium chloride, and lithium bis(fluorosulfonyl)imide were mixed at a mass ratio of 1:2:1, and then added to N,N-dimethylformamide. The mixture was stirred at room temperature for 12 hours to form a homogeneous mixed solution.

[0088] Example 4 The difference from Example 1 is that in the preparation step of the mixed solution, the mass ratio of P(VDF-TrFE), 1-butyl-2,3-dimethylimidazolium chloride, and lithium bis(fluorosulfonyl)imide is 1:1:2. Specifically as follows: (1) Preparation of the mixed solution: P(VDF-TrFE), 1-butyl-2,3-dimethylimidazolium chloride, and lithium bis(fluorosulfonyl)imide were mixed at a mass ratio of 1:1:2, and then added to N,N-dimethylformamide. The mixture was stirred at room temperature for 12 hours to form a homogeneous mixed solution.

[0089] Example 5 The difference from Example 1 is that in the preparation step of the mixed solution, Pyr13TFSI is used to replace 1-butyl-2,3-dimethylimidazolium chloride. Specifically as follows: (1) Preparation of the mixed solution: P(VDF-TrFE), Pyr13TFSI, and lithium bis(fluorosulfonyl)imide were mixed at a mass ratio of 1:1:1, and then added to N,N-dimethylformamide. The mixture was stirred at room temperature for 12 hours to form a homogeneous mixed solution.

[0090] Example 6 The difference from Example 1 is that in the preparation step of the mixed solution, EMIMTFSI is used to replace 1-butyl-2,3-dimethylimidazolium chloride. Specifically as follows: (1) Preparation of the mixed solution: P(VDF-TrFE), EMIMTFSI, and lithium bis(fluorosulfonyl)imide were mixed at a mass ratio of 1:1:1, and then added to N,N-dimethylformamide. The mixture was stirred at room temperature for 12 hours to form a homogeneous mixed solution.

[0091] Example 7 The difference from Example 1 is that in the preparation step of the mixed solution, lithium bis(trifluoromethanesulfonyl)imide is used to replace lithium bis(fluorosulfonyl)imide. Specifically as follows: (1) Preparation of the mixed solution: P(VDF-TrFE), 1-butyl-2,3-dimethylimidazolium chloride, and lithium bis(trifluoromethanesulfonyl)imide were mixed at a mass ratio of 1:1:1, and then added to N,N-dimethylformamide. The mixture was stirred at room temperature for 12 hours to form a homogeneous mixed solution.

[0092] Example 8 The difference from Example 1 is that in the preparation step of the mixed solution, lithium bis(fluorosulfonyl)imide is replaced by lithium perchlorate. Specifically as follows: (1) Preparation of the mixed solution: P(VDF-TrFE), 1-butyl-2,3-dimethylimidazolium chloride, and lithium perchlorate were mixed at a mass ratio of 1:1:1, and then added to N,N-dimethylformamide, and stirred at room temperature for 12 hours to form a uniform mixed solution.

[0093] Example 9 The difference from Example 1 is that in the preparation step of the polymer membrane, the holding time was changed to make the solvent residue of the polymer wet membrane 60%.

[0094] Example 10 The difference from Example 1 is that in the preparation step of the polymer membrane, the holding time was changed to make the solvent residue of the polymer wet membrane 40%.

[0095] Comparative Example 1 The difference from Example 1 is that in the preparation step of the mixed solution, lithium bis(fluorosulfonyl)imide was not added.

[0096] Comparative Example 2 The difference from Example 1 is that in the preparation step of the mixed solution, PVDF was replaced by poly(vinylidene fluoride-trifluoroethylene).

[0097] Comparative Example 3 The difference from Example 1 is that in the preparation step of the polymer wet membrane, the holding time was changed to make the solvent residue of the polymer wet membrane 80%.

[0098] Comparative Example 4 The difference from Example 1 is that in the preparation step of the polymer wet membrane, the holding time was changed to make the solvent residue of the polymer wet membrane 0, obtaining a dry polymer membrane.

[0099] (1) Preparation of the mixed solution: P(VDF-TrFE), 1-butyl-2,3-dimethylimidazolium chloride, and lithium bis(fluorosulfonyl)imide were mixed at a mass ratio of 1:1:1, and then added to N,N-dimethylformamide, and stirred at room temperature for 12 hours to form a uniform mixed solution.

[0100] (2) Preparation of the polymer: The mixed solution obtained in step (1) was coated on a glass substrate by a coater and placed in an oven at 60 °C for 8 hours to obtain a dry polymer membrane.

[0101] (3) The electrolyte membrane body was evenly laid on the dry polymer membrane for use.

[0102] Preparation of the test battery The solid electrolyte membranes prepared in Examples 1 to 10 and Comparative Examples 1 to 4 were separated from the glass substrates, and then assembled with lithium anodes and cathodes to obtain button cells. At a cathode loading of 20 mg / cm 2 The cycle performance of the cells was tested under the conditions of charging at 0.33 C and discharging at 1 C.

[0103] Experimental tests Ionic conductivity test: The solid electrolyte membranes prepared in Examples 1 to 10 and Comparative Examples 1 to 4 were assembled into button cells with steel sheets on both sides. The impedance values were measured at 25 °C, and then the ionic conductivity was calculated according to the formula.

[0104] Cycle performance test: The cells were charged at a constant current and constant voltage of 0.33 C to 4.2 V at 25 °C, and then discharged at a constant current of 1 C to 3.0 V. This was regarded as 1 cycle.

[0105] Cell impedance test: Button cells assembled with lithium anode / / electrolyte / / NCM811 cathode were used to measure the impedance values at 25 °C by an electrochemical tester.

[0106] Safety corresponding cycle number The ionic conductivity of the prepared solid electrolyte membranes was tested, and the test results are shown in Table 1. The cycle performance and cell impedance of the prepared cells were tested, and the test results are shown in Table 2.

[0107] Table 1

[0108] Table 2

[0109] It can be seen from Examples 1 to 10 of the present application that the solid electrolyte membranes provided in the examples of the present application include an electrolyte membrane body and a polymer membrane arranged in a stacked manner, and the polymer membrane includes poly(vinylidene fluoride-trifluoroethylene) and a lithium salt dispersed in the poly(vinylidene fluoride-trifluoroethylene). Calculated by mass ratio, poly(vinylidene fluoride-trifluoroethylene):lithium salt is (0.5 to 2):(0.5 to 2), so that the solid electrolyte membranes in the present application have high ionic conductivity, and the cells with such solid electrolyte membranes have high cycle performance.

[0110] The difference between Example 1 and Comparative Example 1 is that no lithium salt is added to the polymer membrane. It can be seen from Table 1 and Table 2 that adding an appropriate amount of lithium salt to the polymer membrane is beneficial to improving the ionic conductivity and cycling performance. The difference between Example 1 and Comparative Example 2 is that the matrix materials of the polymer membranes are different. It can be seen from Table 1 and Table 2 that, compared with PVDF, the matrix material of the polymer membrane in this application, P(VDF-TrFE), is more conducive to improving the ionic conductivity of the solid electrolyte membrane, and the battery with this solid electrolyte membrane has better cycling performance. In addition, it can be seen from Example 1, Comparative Example 1, and Comparative Example 2 that P(VDF-TrFE) substrate and the lithium salt dispersed therein have a synergistic effect in enhancing the ionic conductivity and cycling performance.

[0111] The difference between Example 2 and Example 1 is that no ionic liquid is added to the raw materials for preparing the polymer membrane. It can be seen from Table 1 and Table 2 that adding an ionic liquid to the polymer membrane is beneficial to further improving the ionic conductivity and cycling performance of the solid electrolyte. It can be seen from Example 1 to Example 4 that poly(vinylidene fluoride-trifluoroethylene): lithium salt: ionic liquid being (0.5 to 2): (0.5 to 2): (1 to 2.5) is beneficial to further improving the ionic conductivity and cycling performance of the solid electrolyte membrane in this application.

[0112] The difference between Example 1, Example 9, Example 10 and Comparative Example 3 and Comparative Example 4 lies in the different processes for preparing the solid electrolyte membrane. The solvent content of the polymer membrane in Example 1 is about 50%, the solvent content of the polymer membrane in Example 9 is about 60%, and the solvent content of the polymer membrane in Example 10 is about 40%, while the solvent content of the polymer membrane in Comparative Example 3 is about 80%, and the polymer membrane prepared in Comparative Example 4 does not include a solvent. It can be seen from Table 1 and Table 2 that if the mass percentage content of the solvent in the polymer membrane is too high, such as higher than 80%, there will be a problem of inability to form a film. An appropriate amount of solvent in the polymer membrane is beneficial to further improving the ionic conductivity and cycling performance. Combining Figures 1 to 4 it can be seen that the possible reason is that the polymer membrane and the solid electrolyte membrane body prepared in the examples of this application are closely attached to form an integral structure, which is beneficial to reducing the impedance and improving the battery cycle.

[0113] The technical solutions provided by the embodiments of this application have been introduced in detail above. Specific examples are used in this article to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those skilled in the art, according to the idea of this application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A solid electrolyte membrane, characterized in that, The solid electrolyte membrane includes an electrolyte membrane body and a polymer membrane arranged in a laminated manner, and the polymer membrane is arranged on at least one side of the electrolyte membrane body; wherein, the polymer membrane includes poly(vinylidene fluoride-trifluorochloroethylene) and a lithium salt dispersed in the poly(vinylidene fluoride-trifluorochloroethylene), and by mass ratio, poly(vinylidene fluoride-trifluorochloroethylene): lithium salt is (0.5 to 2): (0.5 to 2).

2. The solid electrolyte membrane according to claim 1, wherein The polymer membrane is adhered to the electrolyte membrane body through the poly(vinylidene fluoride-trifluorochloroethylene); and / or The polymer membrane further includes a solvent; and / or The electrolyte membrane body is an alkaline membrane; and / or The polymer membrane further includes an ionic liquid, and by mass ratio, the poly(vinylidene fluoride-trifluorochloroethylene): the lithium salt: the ionic liquid is (0.5 to 2): (0.5 to 2): (0.5 to 2.5).

3. The solid electrolyte membrane according to claim 2, wherein The poly(vinylidene fluoride-trifluorochloroethylene): the lithium salt: the ionic liquid is (0.9 to 1.1): (0.9 to 1.1): (0.9 to 2.5); and / or The mass content of the solvent in the polymer membrane is 5% to 10%; and / or The polymer membrane and the electrolyte membrane body form an integral structure; and / or The solvent is an organic solvent.

4. The solid electrolyte membrane according to any one of claims 1 to 3, characterized in that, The thickness of the polymer membrane is 5 μm to 10 μm.

5. The solid electrolyte membrane according to claim 4, wherein The lithium salt is selected from one or more of LiCl, LiBr, LiI, LiFSI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 , LiBOB, LiCF3SO3, LiTFSI, LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI.

6. The solid electrolyte film according to claim 4, characterized in that, The ionic liquid contains an organic cation and an organic or inorganic anion; the organic cation includes at least one of a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation with a pyrroline skeleton, a cation with a pyrrole skeleton, an imidazolium cation, a tetrahydropyrimidinium cation, a dihydropyrimidinium cation, a pyrazolium cation, a pyrazolinium cation, a tetraalkylammonium cation, a trialkylsulfonium cation or a tetraalkylphosphonium cation; and / or The organic or inorganic anions include F - , Cl - , Br - , I - , NO3 - , (CN)2N - , BF4 - , ClO4 - , RSO3 - , RCOO - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , (C2F5SO2)2N - , (CF3SO3)2N - , (CF3SO2)(CF3CO)N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3COO - , C3F7COO - , CF3SO3 - , C4F9SO3 - and at least one of the following 7. A method for preparing the solid electrolyte membrane according to any one of claims 1 to 6, characterized in that, The preparation method includes the following steps: Providing a mixed solution, wherein the mixed solution is obtained by dissolving poly(vinylidene fluoride-trifluorochloroethylene) and a lithium salt in a solvent; Coating the mixed solution on a substrate; Obtaining a polymer membrane after removing part of the solvent; Stacking the polymer membrane on at least one side of the electrolyte membrane body; Performing heat treatment to obtain a solid electrolyte membrane.

8. The preparation method according to claim 7, wherein The heat treatment includes: keeping warm in an oven at a temperature of 40°C to 70°C for 2 hours to 10 hours; and / or In the step of removing part of the solvent, by mass, the mass percentage of the solvent in the obtained polymer membrane is 60% to 40%; and / or In the step of obtaining the solid electrolyte membrane by heat treatment, the mass percentage of the solvent in the polymer membrane in the solid electrolyte membrane is 5% to 10%; and / or The step of providing the mixed solution includes: adding an ionic liquid and a lithium salt to a solvent, and mixing and stirring evenly to obtain a mixed solution.

9. The preparation method according to claim 7, characterized in that, In the coating step, the coating thickness of the mixed solution is 5 μm to 10 μm; and / or The lithium salt is selected from one or more of LiCl, LiBr, LiI, LiFSI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 , LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiCH3SO3, LiCF3CO2, LiCH3CO2 and LiBETI (LiN(SO2CF2CF3)2); and / or The ionic liquid contains an organic cation and an organic or inorganic anion; the organic cation includes at least one of a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation with a pyrroline skeleton, a cation with a pyrrole skeleton, an imidazolium cation, a tetrahydropyrimidinium cation, a dihydropyrimidinium cation, a pyrazolium cation, a pyrazolinium cation, a tetraalkylammonium cation, a trialkylsulfonium cation or a tetraalkylphosphonium cation; and / or The organic or inorganic anions include F - , Cl - , Br - , I - , NO3 - , (CN)2N - , BF4 - , ClO4 - , RSO3 - , RCOO - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , (C2F5SO2)2N - , (CF3SO3)2N - , (CF3SO2)(CF3CO)N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3COO - , C3F7COO - , CF3SO3 - , C4F9SO3 - and at least one of the following: The poly(vinylidene fluoride-chlorotrifluoroethylene) accounts for 10% to 20% of the mass ratio of the mixed solution; and / or The solvent accounts for 40% to 60% of the mass ratio of the mixed solution.

10. A lithium-ion battery, characterized in that, It includes a positive electrode, a negative electrode, and the solid electrolyte membrane according to any one of claims 1 to 6 or the solid electrolyte membrane obtained by the preparation method according to any one of claims 7 to 9.

Images