Solid-state electrolyte membrane, method for producing the same, and battery

Abstract

This invention relates to the field of battery technology, and proposes a solid electrolyte membrane, its preparation method, and a battery thereof. The solid electrolyte membrane comprises a polymer matrix and a lithium salt and an organic-inorganic composite distributed within the polymer matrix; the organic-inorganic composite has a three-dimensional cross-linked network structure consisting of an aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine covalently cross-linked. Through the above technical solution, the solid electrolyte membrane exhibits excellent ionic conductivity and mechanical properties.

Description

Technical Field

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

[0002] Solid-state lithium batteries are widely regarded as a crucial development direction for next-generation energy storage technology due to their combination of high safety and high energy density. As the core component of solid-state lithium batteries, the performance of the solid electrolyte membrane directly determines the battery's energy density, cycle life, and safety reliability. Polymer electrolyte membranes have gained widespread attention due to their excellent interfacial affinity, high solubility for different lithium salts, and good processing performance. However, the crystalline structure of polymers limits their ion transport efficiency, resulting in low room-temperature conductivity. Simultaneously, insufficient mechanical properties and interfacial stability, and the inability to suppress lithium dendrite growth, are also common problems that urgently need to be addressed.

[0003] To overcome the limitations of polymer electrolyte membranes, inorganic solid electrolytes are often dispersed within a polymer matrix to prepare organic-inorganic composite polymer electrolyte membranes. These composite membranes combine the flexibility and processability of polymer electrolyte membranes with the high ionic conductivity, wide electrochemical window, and mechanical rigidity of inorganic solid electrolytes. However, during the preparation process, the introduction of inorganic solid electrolytes into the polymer system via traditional physical mixing methods often results in uneven distribution. This hinders lithium-ion migration, affecting the ionic conductivity of the organic-inorganic composite polymer electrolyte membrane, and also leads to a decrease in its mechanical properties. Summary of the Invention

[0004] This invention proposes a solid electrolyte membrane, its preparation method, and a battery to solve or alleviate at least one of the aforementioned problems.

[0005] The technical solution of the present invention is as follows: This invention proposes a solid electrolyte membrane comprising a polymer matrix and a lithium salt and an organic-inorganic composite distributed in the polymer matrix; the organic-inorganic composite has a three-dimensional cross-linked network structure consisting of an aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine covalently cross-linked.

[0006] Preferably, the mass ratio of the polymer matrix to the lithium salt is 1~3:0.5~1.

[0007] Preferably, the mass ratio of the polymer matrix to the aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine is 1~4:1~1.5:0.5~1:1.5~2.

[0008] Preferably, the polymer matrix includes at least one of polyethylene oxide, polyvinylidene fluoride, poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, and polymethyl methacrylate.

[0009] Preferably, the lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium difluorooxalate borate.

[0010] Preferably, the aminated inorganic solid electrolyte is an inorganic solid electrolyte with aminosilane grafted onto its surface.

[0011] Preferably, the mass ratio of inorganic solid electrolyte to aminosilane is 10~20:0.5~1.

[0012] Preferably, the aminosilane includes at least one of 3-aminopropyltriethoxysilane, 3-aminopropylmethoxysilane, and 3-aminopropylmethyldiethoxysilane.

[0013] Preferably, the inorganic solid electrolyte includes at least one of tantalum-doped lithium lanthanum zirconium oxide, lithium lanthanum zirconium oxide, lithium titanium aluminum phosphate, and lithium germanium aluminum phosphate, and the D50 particle size of the inorganic solid electrolyte is 100~1000nm.

[0014] The present invention also proposes a method for preparing the aforementioned solid electrolyte membrane, comprising: Provides polymer matrices, lithium salts, aminated inorganic solid electrolytes, polyethylene glycol diglycidyl ether, and polyetheramines; The polymer matrix and lithium salt are added to a solvent and mixed to obtain a polymer solution; The aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine are added to the polymer solution and mixed to obtain a slurry. The slurry is formed into a film to obtain the solid electrolyte membrane.

[0015] Preferably, the film-forming temperature is 80~120℃ and the time is 10~14h.

[0016] The present invention also proposes a battery comprising the solid electrolyte membrane described above or the solid electrolyte membrane prepared by the preparation method described above.

[0017] The beneficial effects of this invention are as follows: In this invention, an aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine are covalently crosslinked in situ through ring-opening, forming an organic-inorganic composite with a three-dimensional crosslinked network structure. This organic-inorganic composite uses chemical bonds to anchor the rigid inorganic solid electrolyte within a flexible polymer network structure, thereby enabling the solid electrolyte membrane to possess excellent ionic conductivity and mechanical properties through its overall synergistic effect.

[0018] Specifically, firstly, the amino groups on the surface of the aminated inorganic solid electrolyte react with the epoxy functional groups in polyethylene glycol diglycidyl ether to form covalent bonds. By constructing a stable inorganic-organic chemical bonding interface, the problems of easy aggregation and uneven distribution of inorganic solid electrolytes in polymer systems are solved, and the interfacial impedance between inorganic and organic phases is reduced, thus constructing a continuous ion transport path and improving ion transport efficiency. Secondly, the three-dimensional cross-linked network structure distributed in the polymer matrix can optimize ion transport channels and inhibit polymer crystallization, thereby improving ionic conductivity. Thirdly, the inorganic solid electrolyte, as a rigid framework particle, is tightly connected to the flexible three-dimensional cross-linked polymer network structure through chemical bonds, forming a rigid-flexible coupled composite structure. This not only improves the mechanical properties of the solid electrolyte membrane but also effectively inhibits lithium dendrite puncture and growth, improving the cycle stability and safety of the battery. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Here is a SEM image of the solid electrolyte membrane prepared in Example 1; Figure 2 This is a SEM image of the solid electrolyte membrane prepared in Example 2. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0022] Introducing inorganic solid electrolytes into polymer matrices can lead to the following problems: First, inorganic solid electrolytes tend to agglomerate, making it difficult to disperse uniformly within the polymer matrix, resulting in an uneven microstructure of the solid electrolyte membrane and obstructed lithium-ion transport pathways. Second, the poor interfacial compatibility and high interfacial impedance between the inorganic solid electrolyte and the polymer matrix hinder lithium-ion transport at the interface, reducing the overall ionic conductivity. Third, the limited mechanical properties of the polymer matrix itself, coupled with the introduction of inorganic solid electrolytes, disrupt the continuity and entanglement of polymer molecular chains, further degrading the mechanical properties of the solid electrolyte membrane. Fourth, the surface of inorganic solid electrolytes often contains impurities such as lithium carbonate or exhibits a certain degree of alkalinity, making it prone to side reactions with the polymer matrix or lithium salts, worsening interfacial chemical stability, and causing a continuous decline in ionic conductivity.

[0023] To address the aforementioned issues, the invention patent with publication number CN114927753A constructs a composite solid electrolyte membrane with a cellulose-based membrane substrate and a solid electrolyte layer on the substrate surface by directly dripping a composite solid electrolyte slurry onto the surface of a cellulose-based membrane. While this invention patent achieves the suppression of lithium dendrites in the composite solid electrolyte membrane and ensures good ionic conductivity, its mechanical properties are primarily determined by the cellulose-based membrane; the modification of the inorganic solid electrolyte does not substantially affect the mechanical properties of the composite solid electrolyte membrane.

[0024] The present invention constructs a rigid-flexible coupled three-dimensional cross-linked network structure in a polymer matrix. This network structure not only improves the mechanical properties of the solid electrolyte membrane and inhibits the puncture and growth of lithium dendrites, but also gives the solid electrolyte membrane good ionic conductivity.

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the following description will be provided through embodiments.

[0026] A specific embodiment of the first aspect of the present invention provides a solid electrolyte membrane comprising a polymer matrix and a lithium salt and an organic-inorganic composite distributed in the polymer matrix.

[0027] The polymer matrix, as a continuous phase substrate, provides film-forming properties and flexibility, supporting and dispersing lithium salts and organic-inorganic complexes. The polymer matrix material can be selected from any polymer known in the art, for example, including but not limited to at least one of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyacrylonitrile (PAN), and polymethyl methacrylate (PMMA), preferably polyvinylidene fluoride.

[0028] Lithium salts can dissociate into freely moving lithium ions, which are the source of charge carriers for ion conduction. The lithium salt can be selected from any known in the art, for example, including but not limited to at least one of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluoromethanesulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), and lithium difluorooxalate borate (LiDFOB), preferably lithium bis(trifluoromethanesulfonyl)imide. Preferably, the mass ratio of polymer matrix to lithium salt is 1~3:0.5~1. Within this range, the mechanical properties and ionic conductivity of the solid electrolyte membrane can be better balanced.

[0029] The organic-inorganic composite possesses a rigid-flexible coupled three-dimensional cross-linked network structure. This three-dimensional cross-linked network structure is formed by in-situ ring-opening covalent cross-linking of amino groups on the surface of aminated inorganic solid electrolytes, amino groups in polyetheramines, and epoxy functional groups in polyethylene glycol diglycidyl ether. This not only solves the problems of easy aggregation and uneven distribution of inorganic solid electrolytes, but also simultaneously improves the ion transport performance and mechanical properties of solid electrolyte membranes. Specifically, the aminated inorganic solid electrolyte introduces highly reactive amino functional groups onto the surface of the inorganic solid electrolyte. This introduction is achieved by mixing and reacting the inorganic solid electrolyte with amino-containing organic molecules in a specific solvent, thereby anchoring the amino functional groups to the surface of the inorganic solid electrolyte. The inventors discovered that the performance of the solid electrolyte membrane varies significantly depending on the type of amino-containing organic molecule; when the amino-containing organic molecule is an aminosilane, the solid electrolyte membrane exhibits superior performance. The inorganic solid electrolyte can be selected from any known in the art, for example, including but not limited to at least one of tantalum-doped lithium lanthanum zirconium oxide (LLZTO), lithium lanthanum zirconium oxide (LLZO), lithium titanium aluminum phosphate (LATP), and lithium germanium aluminum phosphate (LAGP), preferably tantalum-doped lithium lanthanum zirconium oxide. The D50 particle size of the inorganic solid electrolyte can be 100~1000 nm, for example, including but not limited to any single value and a range between two values ​​from 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, and 1000 nm. The weight-average molecular weight of the polyetheramine can be 600~20000, for example, including but not limited to any single value and a range between two values ​​from 600, 1000, 5000, 10000, 15000, and 20000. The weight-average molecular weight of polyethylene glycol diglycidyl ether can be 500-2000, for example, including but not limited to any value among 500, 1000, 1500, and 2000, and the range between any two values. Preferably, the mass ratio of the polymer matrix, the aminated inorganic solid electrolyte, the polyethylene glycol diglycidyl ether, and the polyetheramine is 1-4:1-1.5:0.5-1:1.5-2. Within this range, the organic-inorganic composite can be more uniformly distributed in the polymer matrix. Furthermore, this ratio range ensures, on the one hand, that the aminated inorganic solid electrolyte, the polyethylene glycol diglycidyl ether, and the polyetheramine are fully cross-linked to form a more stable three-dimensional cross-linked network structure, further enhancing the mechanical properties of the solid electrolyte membrane and further suppressing lithium dendrites; on the other hand, it allows for better control of the cross-linking density, optimizing ion transport channels, thereby further improving ionic conductivity. More preferably, the mass ratio of the polymer matrix, the aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and the polyetheramine is 2:1:0.8:1.5~2. Within this range, the mechanical properties of the solid electrolyte membrane are significantly improved.

[0030] In one embodiment of the present invention, the aminated inorganic solid electrolyte is an inorganic solid electrolyte with aminosilane grafted onto its surface.

[0031] In this invention, the aminosilane can be any known in the art, for example, including but not limited to at least one of 3-aminopropyltriethoxysilane, 3-aminopropylmethoxysilane, and 3-aminopropylmethyldiethoxysilane, preferably 3-aminopropylmethoxysilane. The aminosilane not only has terminal amino groups but also hydrolyzable alkoxy groups. The alkoxy groups can condense with the hydroxyl groups on the surface of the inorganic solid electrolyte to form stable silicon-oxygen inorganic covalent bonds, while the terminal amino groups can tightly connect the inorganic solid electrolyte to the flexible polymer network structure through covalent bonds, thereby forming a rigid-flexible coupled three-dimensional cross-linked network structure. Through this double-terminal covalent bond interaction, the aminosilane forms a stable molecular bridge between the organic and inorganic phases, achieving a strong chemical bond. In contrast, the modification of other organic molecules containing amino groups, such as polydopamine modification formed by the self-polymerization of dopamine, is essentially a physical coating and is easily detached during use. Preferably, the mass ratio of inorganic solid electrolyte to aminosilane is 10~20:0.5~1. Within this range, the appropriate amount of aminosilane ensures sufficient grafting onto the surface of the inorganic solid electrolyte, which can further improve interfacial compatibility and inhibit aggregation; it also avoids the inorganic solid electrolyte from self-condensation and cross-linking due to excessive aminosilane dosage.

[0032] A second aspect of the present invention provides a method for preparing a solid electrolyte membrane, used to prepare the solid electrolyte membrane provided in the first aspect of the present invention, comprising the following steps: S1 provides a polymer matrix, lithium salt, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine; S2. Add the polymer matrix and lithium salt to the solvent and mix to obtain a polymer solution; add the aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether and polyetheramine to the polymer solution and mix to obtain a slurry; S3. Form the slurry into a film to obtain a solid electrolyte membrane.

[0033] In step S1 of this invention, the preparation of the aminated inorganic solid electrolyte can be carried out by any method known in the art, preferably a wet chemical method. Taking the preparation of the aminated inorganic solid electrolyte using aminosilane as an example, the specific method is as follows: using water and ethanol in a volume ratio of 1~1.5:1~1.5 as a mixed solvent, aminosilane, inorganic solid electrolyte and mixed solvent are added to a reactor. Based on the total mass of aminosilane, inorganic solid electrolyte and mixed solvent, 1%~2% by mass of triethylamine is added. The reaction is carried out at 60~80℃ and stirred at a stirring speed of 300~600 r / min for 24~48 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected and washed with anhydrous ethanol to remove surface residues, and dried in a drying oven at 60~80℃ to obtain the aminated inorganic solid electrolyte.

[0034] In step S2 of this invention, when preparing the polymer solution, the solvent can be at least one selected from N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), and acetonitrile (ACN), preferably N,N-dimethylformamide. To accelerate the dissolution of the polymer matrix, the mixture can be stirred at 200-300 r / min for 2-4 hours at 40-60°C. When preparing the slurry, to ensure the homogeneity of the slurry system, the mixture can be stirred at 400-500 r / min for 10-12 hours at 40-60°C.

[0035] Step S3 of the present invention can be specifically referred to as follows: the slurry is poured onto a polytetrafluoroethylene mold or a glass plate mold, and then placed in a drying oven and dried at 80~120℃ for 10~14h to form a film, thereby obtaining a solid electrolyte membrane.

[0036] A specific embodiment of the third aspect of the present invention provides a battery, the battery including a positive electrode, a negative electrode and a solid electrolyte membrane between the two, the battery membrane being prepared by the solid electrolyte membrane provided in the specific embodiment of the first aspect of the present invention or the solid electrolyte membrane prepared by the preparation method provided in the specific embodiment of the second aspect of the present invention.

[0037] The present invention will now be described in detail with reference to preferred embodiments and comparative examples. The preferred embodiments of the invention described below can be modified in various ways, and therefore the scope of the invention should not be construed as limited to the preferred embodiments described in detail below. Preferred embodiments are provided to help those skilled in the art to more readily understand the invention.

[0038] In the following examples and comparative examples, the weight-average molecular weight of polyvinylidene fluoride was 130,000; the weight-average molecular weight of polyethylene glycol diglycidyl ether was 400; the weight-average molecular weight of polyetheramine was 2,000; the weight-average molecular weight of poly(vinylidene fluoride-co-hexafluoropropylene) was 400,000; and the weight-average molecular weight of polyethylene oxide was 500,000.

[0039] Example 1 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:1:200. Based on the total mass of the three, 1% triethylamine is added. The reaction is carried out at 80°C and stirred at a stirring speed of 400 r / min for 24 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide are added to a container at a mass ratio of 1:0.8, followed by the addition of N,N-dimethylformamide at a mass ratio of 10 times that of polyvinylidene fluoride. The mixture is stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine, and the polymer solution are mixed at a mass ratio of 1:0.8:2:20 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane. The SEM image of the solid electrolyte membrane is shown below. Figure 1 As shown in the figure, the solid electrolyte membrane has good uniformity, and there is no obvious agglomeration of inorganic solid electrolyte particles.

[0040] Example 2 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:1:200. Based on the total mass of the three, 1% triethylamine is added. The reaction is carried out at 80°C and stirred at a stirring speed of 400 r / min for 24 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, and then N,N-dimethylformamide (NDM) at a mass ratio of 10 times that of polyvinylidene fluoride was added. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1:0.8:2:10 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane. The SEM image of the solid electrolyte membrane is shown below. Figure 2 As shown in the figure, the solid electrolyte membrane has good uniformity, and there is no obvious agglomeration of inorganic solid electrolyte particles.

[0041] Example 3 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 10:1:200. Based on the total mass of the three, 1% triethylamine is added. The reaction is carried out at 80°C and stirred at a stirring speed of 400 r / min for 24 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, and then N,N-dimethylformamide (NDM) at a mass ratio of 10 times that of polyvinylidene fluoride was added. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1:0.8:2:20 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0042] Example 4 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 10:1:200. Based on the total mass of the three, 1% triethylamine is added. The reaction is carried out at 80°C and stirred at a stirring speed of 400 r / min for 24 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, and then N,N-dimethylformamide (NDM) at a mass ratio of 10 times that of polyvinylidene fluoride was added. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1:0.8:2:10 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0043] Example 5 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:1:200. Based on the total mass of the three, 1% triethylamine is added. The reaction is carried out at 80°C and stirred at a stirring speed of 400 r / min for 24 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, followed by the addition of N,N-dimethylformamide at a mass ratio of 8.2 times that of polyvinylidene fluoride. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine, and the polymer solution were mixed at a mass ratio of 1:0.8:2.5:20 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0044] Example 6 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:1:200. Based on the total mass of the three, 1% triethylamine is added. The reaction is carried out at 80°C and stirred at a stirring speed of 400 r / min for 24 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, and then N,N-dimethylformamide (NDM) at a mass ratio of 10 times that of polyvinylidene fluoride was added. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1:1.2:2:20 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0045] Example 7 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:1:200. Based on the total mass of the three, 1% triethylamine is added. The reaction is carried out at 80°C and stirred at a stirring speed of 400 r / min for 24 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, and then N,N-dimethylformamide (NDM) at a mass ratio of 10 times that of polyvinylidene fluoride was added. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1.2:0.8:2:20 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0046] Example 8 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:1:200. Based on the total mass of the three, 1% triethylamine is added. The reaction is carried out at 80°C and stirred at a stirring speed of 400 r / min for 24 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, and then N,N-dimethylformamide (NDM) at a mass ratio of 10 times that of polyvinylidene fluoride was added. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1:0.8:2:20 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0047] Example 9 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, lithium aluminum titanium phosphate (D50 particle size of 600nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:1:200. Based on the total mass of the three, 1% triethylamine is added. The mixture is stirred at 80°C and 400r / min for 24h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. The solid is then dried in a drying oven at 60°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, and then N,N-dimethylformamide (NDM) at a mass ratio of 10 times that of polyvinylidene fluoride was added. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1:0.8:2:20 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0048] Example 10 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:0.5:200. Based on the total mass of the three, 2% triethylamine is added. The reaction is carried out at 60°C and stirred at a stirring speed of 400 r / min for 48 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 80°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.5, and then N,N-dimethylformamide (8.5 times the mass of polyvinylidene fluoride) was added. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1:0.5:1.5:10 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0049] Example 11 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine. The preparation method of the aminated inorganic solid electrolyte is as follows: using water and ethanol in a volume ratio of 1:1 as a mixed solvent, tantalum-doped lithium lanthanum zirconium oxide (D50 particle size of 600 nm), 3-aminopropylmethoxysilane, and the mixed solvent are added to the reactor in a mass ratio of 20:0.5:200. Based on the total mass of the three, 2% triethylamine is added. The reaction is carried out at 60°C and stirred at a stirring speed of 400 r / min for 48 h. After the reaction is completed, the supernatant is removed by centrifugation, the solid is collected, and it is washed and centrifuged three times with anhydrous ethanol to remove surface residues. It is then dried in a drying oven at 80°C to obtain the aminated inorganic solid electrolyte. S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 3:1, followed by the addition of N,N-dimethylformamide at a mass ratio of 11 times that of polyvinylidene fluoride. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine and polymer solution were mixed at a mass ratio of 1.5:1:2:20 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0050] Example 12 The only difference between this embodiment and Embodiment 5 is that in this embodiment, the mass ratio of the aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine, and polymer solution is 1:0.8:1.2:20.

[0051] Example 13 The only difference between this embodiment and Embodiment 5 is that in this embodiment, the mass ratio of the aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine, and polymer solution is 1:0.8:1.5:20.

[0052] Example 14 The only difference between this embodiment and Embodiment 5 is that in this embodiment, the mass ratio of the aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, polyetheramine, and polymer solution is 1:0.8:2:20.

[0053] Example 15 The only difference between this embodiment and Embodiment 1 is that, in this embodiment, the D50 particle size of the tantalum-doped lithium lanthanum zirconium oxide is 100 nm, and the polymer matrix is ​​poly(vinylidene fluoride-co-hexafluoropropylene).

[0054] Example 16 The only difference between this embodiment and Embodiment 1 is that, in this embodiment, the D50 particle size of the tantalum-doped lithium lanthanum zirconium oxide is 300 nm, and the polymer matrix is ​​polyethylene oxide.

[0055] Example 17 The only difference between this embodiment and Embodiment 1 is that, in this embodiment, the D50 particle size of the tantalum-doped lithium lanthanum zirconium oxide is 800 nm, and the polymer matrix is ​​polyethylene oxide.

[0056] Example 18 The only difference between this embodiment and Embodiment 1 is that in this embodiment, the D50 particle size of the tantalum-doped lithium lanthanum zirconium oxide is 1000 nm, and the polymer matrix is ​​poly(vinylidene fluoride-co-hexafluoropropylene).

[0057] Comparative Example 1 A method for preparing a solid electrolyte membrane includes the following steps: S1. Prepare polyvinylidene fluoride, lithium bis(trifluoromethanesulfonyl)imide, polyethylene glycol diglycidyl ether and polyetheramine; S2. Polyvinylidene fluoride and lithium bis(trifluoromethanesulfonyl)imide were added to a beaker at a mass ratio of 1:0.8, followed by the addition of N,N-dimethylformamide at a mass ratio of 10 times that of polyvinylidene fluoride. The mixture was stirred at 200 r / min for 2 h at 45 °C to obtain a polymer solution. Polyethylene glycol diglycidyl ether, polyetheramine, and the polymer solution were mixed at a mass ratio of 0.8:2:10 and stirred at 400 r / min for 12 h at 45 °C to obtain a slurry. S3. The slurry is poured onto a polytetrafluoroethylene mold and dried in a drying oven at 80°C for 12 hours to obtain a solid electrolyte membrane.

[0058] Comparative Example 2 The only difference between this comparative example and Example 2 is that, in this comparative example, the aminated inorganic solid electrolyte is replaced with an equal amount of tantalum-doped lithium lanthanum zirconium oxide.

[0059] Experiment Example 1: Mechanical Performance Testing The solid electrolyte membranes prepared in Examples 1-18 and Comparative Examples 1-2 were subjected to the following performance tests: (1) Thickness test: The thickness of the solid electrolyte membrane was tested in accordance with GB / T 36363-2018; (2) Tensile strength test: The solid electrolyte membrane was subjected to longitudinal tensile test in accordance with GB / T 36363-2018. The size of the solid electrolyte membrane was 100×20mm and the tensile speed was 250mm / min. (3) Elongation at break: The solid electrolyte membrane was subjected to longitudinal tensile test in accordance with GB / T 36363-2018. The size of the solid electrolyte membrane was 100×20mm and the tensile speed was 250mm / min.

[0060] The test results are shown in Table 1 below.

[0061] Table 1 Mechanical Performance Test Results

[0062] The comparison between Example 2 and Comparative Examples 1-2 shows that the mechanical properties of solid electrolyte membranes can be significantly improved by using an aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine to form an organic-inorganic composite with a three-dimensional cross-linked network structure through in-situ ring-opening covalent cross-linking.

[0063] Experiment Example 2: Ion Transport Performance Test The solid electrolyte membranes prepared in Examples 1-18 and Comparative Examples 1-2 were subjected to the following performance tests: (4) Ionic conductivity: In a glove box, button cells were assembled in the order of negative electrode shell, spring sheet, steel sheet, electrolyte membrane, steel sheet, and positive electrode shell. After standing at room temperature for 12 hours, their impedance values ​​were measured by AC impedance method. The test frequency was 0.1~10. 6 The ionic conductivity is calculated using the formula σ=L / RS, where S is the effective area of ​​the electrode, L is the thickness of the electrolyte membrane, and R is the measured impedance value of the electrolyte membrane. (5) Lithium-ion transference number: In a glove box, button cells were assembled in the following order: negative electrode shell, spring sheet, steel sheet, lithium sheet, electrolyte membrane, lithium sheet, and positive electrode shell. After standing at room temperature for 12 hours, the constant potential polarization current of the electrolyte membrane and the AC impedance before and after polarization were tested using the time-steady-state current method. The polarization voltage was 0.01V, the polarization time was 3000s, and the polarization current test sampling interval was 0.1s. According to the formula t Li+ =I SS (ΔV) - I0R0) / I0(ΔV-I) SS R SS Calculate its lithium-ion transference number, where R0 and R... ss These are the initial interface impedance of the battery and the interface impedance when the current reaches steady state, respectively; I0 and I... SS These are the initial current and the steady-state current, respectively; ΔV is the constant potential polarization voltage. (6) Electrochemical window test: In the glove box, the button cell was assembled in the order of negative electrode shell, spring, steel sheet, electrolyte membrane, lithium sheet and positive electrode shell. After standing at room temperature for 12 hours, its electrochemical window was tested by linear scanning voltammetry with a voltage range of 0~7V and a scan rate of 0.01V / s.

[0064] The test results are shown in Table 2 below.

[0065] Table 2. Ion transport performance test results

[0066] The comparison between Example 2 and Comparative Examples 1-2 shows that the organic-inorganic composite with a three-dimensional cross-linked network structure formed by in-situ ring-opening covalent cross-linking of aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine can promote interfacial ion transport and thus obtain higher ionic conductivity.

[0067] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solid electrolyte membrane, characterized in that, It includes a polymer matrix and a lithium salt and an organic-inorganic complex distributed in the polymer matrix; the organic-inorganic complex has a three-dimensional cross-linked network structure of an aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine covalently cross-linked.

2. The solid electrolyte membrane according to claim 1, characterized in that, The mass ratio of the polymer matrix to the lithium salt is 1~3:0.5~1.

3. A solid electrolyte membrane according to claim 1, characterized in that, The mass ratio of the polymer matrix, the aminated inorganic solid electrolyte, the polyethylene glycol diglycidyl ether, and the polyetheramine is 1~4:1~1.5:0.5~1:1.5~2.

4. A solid electrolyte membrane according to claim 1, characterized in that, The polymer matrix includes at least one of polyethylene oxide, polyvinylidene fluoride, poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, and polymethyl methacrylate; and / or The lithium salt includes at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium difluorooxalate borate.

5. A solid electrolyte membrane according to any one of claims 1, characterized in that, The aminated inorganic solid electrolyte is an inorganic solid electrolyte with aminosilane grafted onto its surface.

6. A solid electrolyte membrane according to claim 5, characterized in that, The mass ratio of inorganic solid electrolyte to aminosilane is 10~20:0.5~1.

7. A solid electrolyte membrane according to claim 5, characterized in that, The aminosilane comprises at least one of 3-aminopropyltriethoxysilane, 3-aminopropylmethoxysilane, and 3-aminopropylmethyldiethoxysilane; and / or The inorganic solid electrolyte includes at least one of tantalum-doped lithium lanthanum zirconium oxide, lithium lanthanum zirconium oxide, lithium titanium aluminum phosphate, and lithium germanium aluminum phosphate, and the D50 particle size of the inorganic solid electrolyte is 100~1000nm.

8. A method for preparing a solid electrolyte membrane according to any one of claims 1 to 7, characterized in that, include: Provides polymer matrices, lithium salts, aminated inorganic solid electrolytes, polyethylene glycol diglycidyl ether, and polyetheramines; The polymer matrix and lithium salt are added to a solvent and mixed to obtain a polymer solution; The aminated inorganic solid electrolyte, polyethylene glycol diglycidyl ether, and polyetheramine are added to the polymer solution and mixed to obtain a slurry. The slurry is formed into a film to obtain the solid electrolyte membrane.

9. The method for preparing a solid electrolyte membrane according to claim 8, characterized in that, The film-forming temperature is 80~120℃ and the time is 10~14h.

10. A battery, characterized in that, The solid electrolyte membrane includes the solid electrolyte membrane according to any one of claims 1 to 7 or the solid electrolyte membrane prepared by the preparation method according to any one of claims 8 to 9.

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