Flame-retardant flexible solid-state electrolyte material and preparation method and application thereof

Abstract

The application relates to a flame-retardant flexible solid-state electrolyte material and a preparation method and application thereof, and belongs to the technical field of secondary batteries. The method comprises the following steps: dispersing a lithium salt in a perfluoropolyether alcohol to obtain a mixture; modifying a fluorine-containing polymer by using the mixture to obtain a flame-retardant flexible solid-state electrolyte; the high-molecular-weight fluorine-containing polymer with good flame retardance is selected as a matrix, and an oligomer perfluoropolyether alcohol is added to modify the matrix, so that the whole solid-state electrolyte has a wide molecular weight distribution, the flexibility of the solid-state electrolyte is increased on the basis of guaranteeing the mechanical property, and the ion conductivity and the processability of the polymer are improved. After the solid-state electrolyte material is prepared into a solid-state electrolyte film, the solid-state electrolyte film has good flame retardance, the safety performance is improved, and the ion conductivity of the polymer electrolyte film is improved.

Description

Technical Field

[0001] This application relates to the field of secondary battery technology, and in particular to a flame-retardant flexible solid electrolyte material, its preparation method, and its application. Background Technology

[0002] Traditional lithium-ion batteries typically use flammable alkyl carbonate electrolytes, which are susceptible to thermal runaway due to factors such as compression, impact, and short circuits during operation, easily leading to safety accidents. Lithium-ion batteries using solid-state electrolytes offer significantly improved safety because they eliminate the problems of electrolyte evaporation and leakage. However, solid inorganic electrolytes have poor mechanical properties, so solid polymer electrolytes are often used. Common solid polymer electrolytes such as polyethylene oxide and polyurethane are highly flammable in air, and thermal runaway also poses a safety hazard. Furthermore, the regular structure and high crystallinity of polyethylene oxide hinder ion transport, and most solid polymer batteries operate at high temperatures (>50°C) to ensure high ionic conductivity of the polymer electrolyte, while ionic conductivity at room temperature is generally low (approximately 10). -8 S / cm).

[0003] High molecular weight fluoropolymers, as polymer matrices, possess good mechanical properties, chemical stability, and excellent flame retardancy. The presence of fluorine atoms in the polymer matrix improves the electrochemical stability window of solid-state batteries, significantly increasing the probability of forming a dense and uniform solid electrolyte interphase (SEI) layer. However, the high content of CF bonds in fluoropolymers determines their excellent solvent and chemical resistance, and their large molecular weight makes their processing relatively difficult, resulting in lower ion conductivity. Summary of the Invention

[0004] This application provides a flame-retardant flexible solid electrolyte material, its preparation method, and its application, which can improve safety performance while also improving the ionic conductivity of polymer electrolyte membranes.

[0005] In a first aspect, this application provides a method for preparing a flame-retardant flexible solid electrolyte material, the method comprising:

[0006] Lithium salt was dispersed in perfluoropolyether alcohol to obtain a mixture;

[0007] A mixture was used to modify fluoropolymers to obtain a flame-retardant flexible solid electrolyte.

[0008] As an optional implementation method, the structural formula of perfluoropolyether alcohol is:

[0009] Where n is any positive integer.

[0010] As an optional implementation, the number average molecular weight of the perfluoropolyether alcohol is 10. 4 ~10 6 .

[0011] As an optional implementation method, the structural formula of the fluoropolymer is:

[0012]

[0013] Among them, R f Selected from at least one of -CF3, -CF2CF3, -CF2CF2CF3 and -CF2CF2CF2CF3;

[0014] X is selected from at least one of -COOH, -CN, and -OC6F5.

[0015] As an optional implementation, the fluoropolymer has a number-average molecular weight of 10. 4 ~10 6 .

[0016] As an optional implementation, the lithium salt includes at least one of lithium bis(oxalato)borate, lithium difluorooxalato)borate, lithium bis(difluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide.

[0017] As an optional implementation, the mass ratio of the fluoropolymer to the perfluoropolyether alcohol is 10:(2-3); and / or

[0018] The mass ratio of fluoropolymer to lithium salt is 10:(0.2~0.6).

[0019] As an alternative implementation method, the modification is carried out by mixing using an internal mixer.

[0020] Secondly, this application provides a flame-retardant flexible solid electrolyte material, which is prepared using the method provided in the first aspect.

[0021] Thirdly, this application provides a solid electrolyte membrane, the composition of which includes the flame-retardant flexible solid electrolyte material provided in the second aspect.

[0022] As an optional implementation, the thickness of the solid electrolyte membrane is 50 μm to 200 μm.

[0023] Fourthly, this application provides a method for preparing a solid electrolyte membrane, the method comprising:

[0024] The flame-retardant flexible solid electrolyte material provided in the second aspect is obtained;

[0025] As an optional implementation method, the flame-retardant flexible solid electrolyte is hot-pressed into a film to obtain a solid electrolyte membrane.

[0026] The hot pressing temperature for hot pressing film formation is 150℃~230℃; and / or

[0027] The hot pressing pressure for hot pressing film formation is 15MPa to 20MPa; and / or

[0028] The hot pressing time for hot pressing film formation is 30s to 60s.

[0029] The technical solutions provided in this application have the following advantages compared with the prior art:

[0030] The method provided in this application selects a high molecular weight fluoropolymer with good flame retardancy as the matrix and modifies it with oligomeric perfluoropolyether alcohol, giving the solid electrolyte a wide molecular weight distribution. This increases its flexibility while maintaining mechanical properties, and improves ionic conductivity and polymer processability. When prepared into a solid electrolyte membrane, this membrane exhibits good flame retardancy, improving safety performance while also enhancing the ionic conductivity of the polymer electrolyte membrane. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A flowchart illustrating the method provided in the embodiments of this application;

[0034] Figure 2 The graph shows the test results of the AC impedance of the solid electrolyte membranes provided in Examples 1, 2 and Comparative Example 1 of this application. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0037] Figure 1 A flowchart illustrating the method provided in the embodiments of this application, as shown below. Figure 1 As shown in the figure, this application provides a method for preparing a flame-retardant flexible solid electrolyte material, the method comprising:

[0038] S1. Disperse lithium salt in perfluoropolyether alcohol to obtain a mixture;

[0039] In some embodiments, the lithium salt may be selected from lithium bis(oxalato)borate (LiBOB), lithium difluorooxalato)borate (LiDFOB), lithium bis(difluorosulfonyl)imide (LiFSI), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

[0040] In some embodiments, the structural formula of perfluoropolyether alcohol is:

[0041] Where n is any positive integer.

[0042] Furthermore, the number average molecular weight of perfluoropolyether alcohol is 10. 4 ~10 6 .

[0043] In some embodiments, the mass ratio of perfluoropolyether alcohol to lithium salt is (2-3):(0.2-0.6).

[0044] For example, the mass ratio of perfluoropolyether alcohol to lithium salt can be 2:0.4, 2.5:0.4, 3:0.4, 2.5:0.2, 2.5:0.6, 3:0.4 or 3:0.6, etc., or it can be any value in the range of (2 to 3): (0.2 to 0.6).

[0045] S2. A mixture is used to modify the fluoropolymer to obtain a flame-retardant flexible solid electrolyte.

[0046] In some embodiments, the structural formula of the fluoropolymer is:

[0047]

[0048] Among them, R f Selected from at least one of -CF3, -CF2CF3, -CF2CF2CF3 and -CF2CF2CF2CF3;

[0049] X is selected from at least one of -COOH, -CN, and -OC6F5.

[0050] Furthermore, the number-average molecular weight of the fluoropolymer is 10. 4 ~10 6 .

[0051] In some embodiments, the mass ratio of the fluoropolymer to the perfluoropolyether alcohol is 10:(2-3).

[0052] For example, the mass ratio of fluoropolymer to perfluoropolyether alcohol can be 10:2, 10:2.1, 10:2.2, 10:2.3, 10:2.4, 10:2.5, 10:2.6, 10:2.7, 10:2.8, 10:2.9 or 10:3, etc., or it can be any value in the range of 10:(2 to 3).

[0053] In some embodiments, the mass ratio of the fluoropolymer to the lithium salt is 10:(0.2 to 0.6).

[0054] For example, the mass ratio of fluoropolymer to lithium salt can be 10:0.1, 10:0.2, 10:0.3, 10:0.4, 10:0.5 or 10:0.6, etc., or any value in the range of 10:(0.2 to 0.6).

[0055] In some embodiments, the modification is performed by mixing using an internal mixer. The electrolyte film is prepared using an internal mixing and hot pressing process without the addition of solvents, making the entire process more environmentally friendly.

[0056] This method uses a high-molecular-weight fluoropolymer with good flame retardancy as the matrix and modifies it with oligomeric perfluoropolyether alcohols, resulting in a broad molecular weight distribution for the solid electrolyte. This enhances its flexibility, ionic conductivity, and polymer processability while maintaining its mechanical properties. The resulting solid electrolyte membrane exhibits good flame retardancy, improving both safety and ionic conductivity.

[0057] Based on a general inventive concept, embodiments of this application also provide a flame-retardant flexible solid electrolyte material, which is prepared using the method provided above.

[0058] The flame-retardant flexible solid electrolyte material is prepared based on the above method. The specific steps of the method can be referred to the above embodiments. Since the flame-retardant flexible solid electrolyte material adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here.

[0059] Based on a general inventive concept, embodiments of this application also provide a solid electrolyte membrane, the composition of which includes the flame-retardant flexible solid electrolyte material provided above.

[0060] The solid electrolyte membrane is based on the flame-retardant flexible solid electrolyte material described above. The specific details of the flame-retardant flexible solid electrolyte material can be found in the above embodiments. Since the solid electrolyte membrane adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0061] In some embodiments, the thickness of the solid electrolyte membrane is 50 μm to 200 μm.

[0062] For example, the thickness of the solid electrolyte membrane can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm or 200μm, etc., or it can be any value in the range of 50μm to 200μm.

[0063] Based on a general inventive concept, embodiments of this application also provide a method for preparing a solid electrolyte membrane, the method comprising:

[0064] S1. Obtain the flame-retardant flexible solid electrolyte material as provided above;

[0065] S2. The flame-retardant flexible solid electrolyte is hot-pressed into a film to obtain a solid electrolyte film.

[0066] In some embodiments, the hot pressing temperature for hot pressing film formation is 150°C to 230°C; the hot pressing pressure for hot pressing film formation is 15MPa to 20MPa; and the hot pressing time for hot pressing film formation is 30s to 60s.

[0067] For example, the hot pressing temperature for hot pressing film formation can be 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, or 230℃, or any value within the range of 150℃ to 230℃. The hot pressing pressure for hot pressing film formation can be 15MPa, 16MPa, 17MPa, 18MPa, 19MPa, or 20MPa, or any value within the range of 15MPa to 20MPa. The hot pressing time for hot pressing film formation can be 30s, 35s, 40s, 45s, 50s, 55s, or 60s, or any value within the range of 30s to 60s.

[0068] The present application is 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 the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0069] Example 1

[0070] A solid electrolyte membrane is prepared as follows:

[0071] 1. Weigh 2.0g of perfluoropolyether alcohol into a glass bottle, then transfer it to a glove box. Next, weigh 0.2g of lithium bis(trifluoromethanesulfonyl)imide and add it to the bottle. Cap the bottle and place it at room temperature with magnetic stirring for 1 hour to ensure the lithium salt is evenly dispersed.

[0072] 2. Weigh 10.0g of the fluoropolymer and add it together with the above-mentioned perfluoropolyether alcohol into a mixer for mixing until the raw materials are evenly mixed. Add the evenly mixed raw materials to a hot press and hot press at 180℃ and 20MPa for 40s to obtain a flame-retardant flexible solid electrolyte membrane (denoted as FFKM1-PFPE-OH-LiTFSI). Cut the obtained electrolyte membrane into circular pieces with a diameter of 16mm using a film pressing machine and place them in a glove box for later use.

[0073] The thickness of the flame-retardant flexible solid electrolyte membrane prepared in this embodiment was measured to be approximately 105 μm using a thin film thickness gauge. A combustion test was conducted on the flame-retardant flexible solid electrolyte membrane prepared in this embodiment, and the test showed that the flame-retardant flexible solid electrolyte membrane prepared in this embodiment self-extinguished immediately after being removed from the flame.

[0074] Using the flame-retardant flexible solid electrolyte membrane prepared in this embodiment as the solid electrolyte, the impedance of the stainless steel blocking battery was tested using the EIS method. The ionic conductivity of the flame-retardant flexible solid electrolyte membrane prepared in this embodiment at 20°C was calculated using the formula σ = L / (R*S) (where σ is the ionic conductivity, L is the thickness of the electrolyte membrane, R is the bulk impedance, and S is the area of ​​the solid electrolyte membrane). The calculated ionic conductivity was approximately 2.54 × 10⁻⁶. -5 S / cm.

[0075] Example 2

[0076] A solid electrolyte membrane is prepared as follows:

[0077] 1. Weigh 2.0g of perfluoropolyether alcohol into a glass bottle, then transfer it to a glove box. Next, weigh 0.4g of lithium bis(trifluoromethanesulfonyl)imide and add it to the bottle. Cap the bottle and place it at room temperature with magnetic stirring for 1 hour to ensure the lithium salt is evenly dispersed.

[0078] 2. Weigh 10.0g of the fluoropolymer and add it together with the above-mentioned perfluoropolyether alcohol into a mixer for mixing until the raw materials are evenly mixed. Add the evenly mixed raw materials to a hot press and hot press at 180℃ and 20MPa for 40s to obtain a flame-retardant flexible solid electrolyte membrane (denoted as FFKM2-PFPE-OH-LiTFSI). Use a film press to cut the obtained electrolyte membrane into circular pieces with a diameter of 16mm and place them in a glove box for later use.

[0079] The thickness of the flame-retardant flexible solid electrolyte membrane prepared in this embodiment was measured to be approximately 90 μm using a thin film thickness gauge. A combustion test was conducted on the flame-retardant flexible solid electrolyte membrane prepared in this embodiment, and the test showed that the flame-retardant flexible solid electrolyte membrane prepared in this embodiment self-extinguished immediately after being removed from the flame.

[0080] Using the flame-retardant flexible solid electrolyte membrane prepared in this embodiment as the solid electrolyte, the impedance of the stainless steel blocking battery was tested using the EIS method. The ionic conductivity of the flame-retardant flexible solid electrolyte membrane prepared in this embodiment at 20°C was calculated using the formula σ=L / (R*S) to be approximately 3.86×10⁻⁶. -5 S / cm.

[0081] Example 3

[0082] A solid electrolyte membrane is prepared as follows:

[0083] 1. Weigh 3.0g of perfluoropolyether alcohol into a glass bottle, then transfer it to a glove box. Next, weigh 0.3g of lithium bis(trifluoromethanesulfonyl)imide and add it to the bottle. Cap the bottle and place it at room temperature with magnetic stirring for 1 hour to ensure the lithium salt is evenly dispersed.

[0084] 2. Weigh 10.0g of the fluoropolymer and add it together with the above-mentioned perfluoropolyether alcohol into a mixer for mixing until the raw materials are evenly mixed. Add the evenly mixed raw materials to a hot press and hot press at 180℃ and 20MPa for 40s to obtain a flame-retardant flexible solid electrolyte membrane (denoted as FFKM3-PFPE-OH-LiTFSI). Cut the obtained electrolyte membrane into circular pieces with a diameter of 16mm using a film pressing machine and place them in a glove box for later use.

[0085] The thickness of the flame-retardant solid electrolyte membrane prepared in this embodiment was measured to be approximately 100 μm using a thin film thickness gauge. A combustion test was conducted on the flame-retardant flexible solid electrolyte membrane prepared in this embodiment, and the test results showed that the flame-retardant flexible solid electrolyte membrane prepared in this embodiment self-extinguished immediately after being removed from the flame.

[0086] Using the flame-retardant flexible solid electrolyte membrane prepared in this embodiment as the solid electrolyte, the impedance of the stainless steel blocking battery was tested using the EIS method. The ionic conductivity of the flame-retardant flexible solid electrolyte membrane prepared in this embodiment at 20°C was calculated using the formula σ = L / (R*S) (where σ is the ionic conductivity, L is the thickness of the electrolyte membrane, R is the bulk impedance, and S is the area of ​​the solid electrolyte membrane). The calculated ionic conductivity was approximately 3.16 × 10⁻⁶. -5 S / cm.

[0087] Example 4

[0088] A solid electrolyte membrane is prepared as follows:

[0089] 1. Weigh 3.0g of perfluoropolyether alcohol into a glass bottle, then transfer it to a glove box. Next, weigh 0.6g of lithium bis(trifluoromethanesulfonyl)imide and add it to the bottle. Cap the bottle and place it at room temperature with magnetic stirring for 1 hour to ensure the lithium salt is evenly dispersed.

[0090] 2. Weigh 10.0g of the fluoropolymer and add it together with the above-mentioned perfluoropolyether alcohol into a mixer for mixing until the raw materials are evenly mixed. Add the evenly mixed raw materials to a hot press and hot press at 180℃ and 20MPa for 40s to obtain a flame-retardant flexible solid electrolyte membrane (denoted as FFKM4-PFPE-OH-LiTFSI). Cut the obtained electrolyte membrane into circular pieces with a diameter of 16mm using a film pressing machine and place them in a glove box for later use.

[0091] The thickness of the flame-retardant flexible solid electrolyte membrane prepared in this embodiment was measured to be approximately 110 μm using a thin film thickness gauge. A combustion test was conducted on the flame-retardant flexible solid electrolyte membrane prepared in this embodiment, and the test showed that the flame-retardant flexible solid electrolyte membrane prepared in this embodiment self-extinguished immediately after being removed from the flame.

[0092] Using the flame-retardant flexible solid electrolyte membrane prepared in this embodiment as the solid electrolyte, the impedance of the stainless steel blocking battery was tested using the EIS method. The ionic conductivity of the flame-retardant flexible solid electrolyte membrane prepared in this embodiment at 20°C was calculated using the formula σ = L / (R*S) (where σ is the ionic conductivity, L is the thickness of the electrolyte membrane, R is the bulk impedance, and S is the area of ​​the solid electrolyte membrane). The calculated ionic conductivity was approximately 4.55 × 10⁻⁶. -5 S / cm.

[0093] Comparative Example 1

[0094] A solid electrolyte membrane is prepared as follows:

[0095] 1. Weigh 2.0g of perfluoropolyether alcohol into a glass bottle, then transfer it to a glove box. Next, weigh 0.4g of lithium bis(trifluoromethanesulfonyl)imide and add it to the bottle. Cap the bottle and place it at room temperature with magnetic stirring for 1 hour to ensure the lithium salt is evenly dispersed.

[0096] 2. Weigh 10.0g of polyethylene oxide (molecular weight 4*10). 5 The above-mentioned perfluoropolyether alcohol is added to a mixer and mixed to ensure uniform mixing. The uniformly mixed raw materials are then added to a hot press and hot-pressed at 180°C and 20MPa for 40s to obtain a solid electrolyte membrane (denoted as PEO-PFPE-OH-LiTFSI). The obtained electrolyte membrane is then cut into 16mm diameter discs using a film pressing machine and placed in a glove box for later use.

[0097] The thickness of the solid electrolyte membrane prepared in this embodiment was measured to be approximately 110 μm using a thin film thickness gauge. A combustion test was conducted on the solid electrolyte membrane prepared in this comparative example. The test showed that the polyethylene oxide solid electrolyte membrane prepared in this comparative example burned violently when exposed to fire, and there was a melting and dripping phenomenon.

[0098] Using the polyethylene oxide solid electrolyte membrane prepared in this comparative example as the solid electrolyte, the impedance of the stainless steel blocking battery was tested using the EIS method. The ionic conductivity of the polyethylene oxide solid electrolyte membrane prepared in this comparative example at 20℃ was calculated using the formula σ=L / (R*S) to be approximately 6.28×10⁻⁶. -6 S / cm.

[0099] The combustion heat release data of the fluoropolymer flexible solid electrolyte membranes prepared in Examples 1 and 2 and the polyethylene oxide solid electrolyte membrane prepared in Comparative Example 1 are compared in the table below.

[0100]

[0101] As shown in the table above, compared with the polyethylene oxide solid electrolyte membrane prepared in Comparative Example 1, the peak value of the heat release rate and the total heat release amount of the fluoropolymer flexible solid electrolyte membranes prepared in Examples 1 and 2 are reduced to varying degrees, and the temperature required to reach the maximum heat release rate is increased. This is also highly consistent with the previous combustion test results.

[0102] Figure 2 This is a comparison diagram of the AC impedance of the fluoropolymer flexible solid electrolyte membranes prepared in Examples 1 and 2 and the polyethylene oxide solid electrolyte membrane prepared in Comparative Example 1. Figure 2 Analysis of the results revealed that, under the same conditions, the solid electrolyte membrane prepared using fluoropolymers had a significantly higher ionic conductivity than the solid electrolyte membrane prepared using polyethylene oxide, and the ionic conductivity also increased with the increase of lithium salt content.

[0103] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical 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 single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0104] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b or c" or "at least one of a, b and c" can both mean: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0105] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a flame-retardant flexible solid electrolyte material, characterized in that, The method includes: A lithium salt was dispersed in a perfluoropolyether alcohol to obtain a mixture, wherein the perfluoropolyether alcohol has the following structural formula: Where n is any positive integer, and the number-average molecular weight of the perfluoropolyether alcohol is 10. 4 ~10 6 ; The fluoropolymer was modified using the mixture to obtain a flame-retardant flexible solid electrolyte. The structural formula of the fluoropolymer is as follows: ； Among them, R f Selected from at least one of -CF3, -CF2CF3, -CF2CF2CF3 and -CF2CF2CF2CF3; X is selected from at least one of -COOH, -CN, and -OC6F5, and the number-average molecular weight of the fluoropolymer is 10. 4 ~10 6 ; The modification method is to use a mixer for mixing; The mass ratio of the fluoropolymer to the perfluoropolyether alcohol is 10:(2~3). The mass ratio of the fluoropolymer to the lithium salt is 10:(0.2~0.6).

2. The method for preparing the flame-retardant flexible solid electrolyte material according to claim 1, characterized in that, The lithium salt includes at least one of lithium bis(oxalato)borate, lithium difluorooxalato)borate, lithium bis(difluorosulfonyl)imide, and lithium bis(trifluoromethyl)sulfonyl)imide.

3. A flame-retardant flexible solid electrolyte material, characterized in that, The flame-retardant flexible solid electrolyte material is prepared by the method described in any one of claims 1 to 2.

4. A solid electrolyte membrane, characterized in that, The solid electrolyte membrane comprises the flame-retardant flexible solid electrolyte material as described in claim 3; and / or The thickness of the solid electrolyte membrane is 50μm~200μm.

5. A method for preparing a solid electrolyte membrane, characterized in that, The method includes: The flame-retardant flexible solid electrolyte material as described in claim 3 is obtained; The flame-retardant flexible solid electrolyte is hot-pressed into a film to obtain a solid electrolyte membrane.

6. The method for preparing a solid electrolyte membrane according to claim 5, characterized in that, The hot pressing temperature for film formation is 150℃~230℃; and / or The hot pressing pressure for film formation is 15MPa~20MPa; and / or The hot pressing time for hot pressing film formation is 30s~60s.

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