Solid-state electrolyte for lithium battery and preparation method and application thereof

Abstract

This application provides a solid electrolyte for lithium batteries, its preparation method, and its application, belonging to the field of solid electrolyte technology. The electrolyte comprises, by mass parts, 40-75 parts lithium salt, 10-30 parts crosslinking agent, 5-25 parts nano-sized borosilicate glass fiber, and 1-10 parts photoinitiator. The polymer component formed by using lithium salt, crosslinking agent, nano-sized borosilicate glass fiber, and photoinitiator as raw materials and curing them under ultraviolet light possesses high mechanical properties and can form a stable electrolyte-electrode interface. This effectively inhibits the growth of lithium dendrites, reduces the risk of battery short circuits, thereby improving the overall safety of the battery and extending its lifespan. The nano-sized borosilicate glass fiber, as an inorganic filler, helps reduce the crystallinity of the polymer component and increases the amorphous phase region, thus facilitating the rapid migration of lithium ions and improving the battery's ionic conductivity and coulombic efficiency.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte technology, and more specifically to a solid electrolyte for lithium batteries, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries, due to their high energy density, long cycle life, and environmental friendliness, are widely used in electric vehicles, energy storage systems, portable electronic devices, and other fields, becoming an indispensable energy storage device in modern life. However, safety issues caused by traditional electrolytes remain a significant challenge for lithium-ion batteries. Solid-state lithium-ion batteries, which use solid electrolytes instead of traditional electrolytes, promise to improve electrolyte safety. Compared to traditional electrolytes, solid electrolytes have higher mechanical strength, effectively suppressing lithium dendrite growth and reducing the risk of battery short circuits. Furthermore, solid electrolytes possess high chemical stability, are less prone to reacting with electrodes, and reduce battery self-discharge, thereby effectively improving battery cycle life.

[0003] However, existing solid electrolytes have problems such as low ionic conductivity and excessive local current caused by tiny particles inside the battery, which can lead to short circuits and thermal runaway. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a solid electrolyte for lithium batteries, its preparation method and application, aiming to solve the technical problems of low ionic conductivity and easy thermal runaway caused by solid electrolytes.

[0005] In a first aspect, embodiments of this application provide a solid electrolyte for lithium batteries, comprising, by mass parts, 40-75 parts lithium salt, 10-30 parts crosslinking agent, 5-25 parts nano-sized borosilicate glass fiber and 1-10 parts photoinitiator.

[0006] Preferably, the lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluoroborate, lithium dioxalate borate, and lithium difluorooxalate borate.

[0007] Preferably, the crosslinking agent is one or more of methyl methacrylate, acrylonitrile, vinylidene fluoride, and ethylene glycol.

[0008] Preferably, the nano-sized borosilicate glass fiber comprises 70-80 parts silicon dioxide, 6-15 parts boron oxide, 4-10 parts sodium oxide, 0-5 parts aluminum oxide, 0-2 parts calcium oxide, and 0-2 parts barium oxide, wherein the nano-sized borosilicate glass fiber has a particle size of 20-1000 nm.

[0009] Preferably, the photoinitiator is one or more of the following: 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, isopropylthioxanthone, benzophenone, methyl o-benzoylbenzoate, diphenyliodonium hexafluorophosphate, and 4-methylbenzophenone.

[0010] Secondly, embodiments of this application provide a method for preparing a solid electrolyte for lithium batteries, comprising the following steps:

[0011] Lithium salt, crosslinking agent, nano-sized borosilicate glass fiber, and photoinitiator are added to a solvent and stirred to disperse them evenly to obtain a precursor solution.

[0012] The precursor solution was uniformly coated onto the substrate and cured with ultraviolet light to obtain a solid electrolyte.

[0013] Preferably, the solvent is a mixed solution of 1,3-dioxolane and 1,2-dimethoxyethane, wherein the volume ratio of 1,3-dioxolane and 1,2-dimethoxyethane is 1:1, or a mixed solution of ethylene carbonate, diethyl carbonate and dimethyl carbonate, wherein the volume ratio of ethylene carbonate, diethyl carbonate and dimethyl carbonate is 1:1:1; the mass ratio of lithium salt to solvent is (40~75):(22~65).

[0014] Preferably, the stirring speed is 300~800 rpm.

[0015] Preferably, the coating thickness of the precursor solution is 50~200μm, and the ultraviolet curing conditions are: the wavelength of the ultraviolet light is 320nm, and the curing time is 2~20min.

[0016] Thirdly, embodiments of this application provide a lithium battery including the aforementioned solid electrolyte.

[0017] The advantages of this application, which differ from existing technical solutions, include:

[0018] 1. This application uses lithium salt, crosslinking agent, nano-sized borosilicate glass fiber, and photoinitiator as raw materials. The polymer component formed after ultraviolet light curing has high mechanical properties and can form a stable electrolyte-electrode interface, effectively inhibiting the growth of lithium dendrites, reducing the risk of battery short circuits, thereby improving the overall safety of the battery and extending its service life. Nano-sized borosilicate glass fiber, as an inorganic filler, helps reduce the crystallinity of the polymer component and increases the amorphous phase region, which is conducive to the rapid migration of lithium ions and improves the ionic conductivity and coulombic efficiency of the battery.

[0019] 2. Nanoscale borosilicate glass fibers can not only form reinforced composite materials with polymers to improve the mechanical properties of solid electrolytes, but also rapidly form a continuous nano-network structure during thermal runaway, constituting a barrier for mass and heat transfer, hindering the diffusion of oxygen and combustible gases, achieving good flame retardant effects, and further improving the safety performance of batteries.

[0020] 3. The introduction of nano-sized borosilicate glass fiber also gives the solid electrolyte low toxicity and environmental protection characteristics: during combustion, it will form low toxicity or non-toxic compounds (such as SiO2, B2O3, etc.) and will not release harmful substances (such as HCl, HCN, etc.), which meets environmental protection requirements.

[0021] Therefore, the novel solid electrolyte designed in this application is environmentally friendly, has high mechanical properties and thermal stability, and its application in lithium batteries can effectively improve the overall safety, environmental friendliness and cycle performance of the battery.

[0022] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0024] Figure 1 The graph shows the capacity retention of a lithium-sulfur battery prepared using the solid electrolyte prepared in Example 1.

[0025] Figure 2 The graph shows the capacity retention of a lithium-sulfur battery prepared using the solid electrolyte of Comparative Example 1.

[0026] Figure 3 The capacity retention test graph of the lithium-sulfur battery prepared with the solid electrolyte of Comparative Example 2. Detailed Implementation

[0027] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0029] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0030] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0032] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0033] Existing solid electrolytes have problems such as low ionic conductivity and excessive local current caused by tiny particles inside the battery, which can lead to short circuits and thermal runaway.

[0034] To address the technical challenges of low ionic conductivity and susceptibility to thermal runaway in solid-state electrolytes, this application provides a solid-state electrolyte for lithium batteries, its preparation method, and its application. Using lithium salt, crosslinking agent, nano-sized borosilicate glass fiber, and photoinitiator as raw materials, the polymer component formed after UV curing exhibits high mechanical properties and can form a stable electrolyte-electrode interface. This effectively inhibits lithium dendrite growth, reduces the risk of battery short circuits, thereby improving overall battery safety and extending battery life. The nano-sized borosilicate glass fiber, as an inorganic filler, helps reduce the crystallinity of the polymer component and increases the amorphous phase region, thus facilitating rapid lithium ion migration and improving the battery's ionic conductivity and coulombic efficiency.

[0035] In a first aspect, embodiments of this application provide a solid electrolyte for lithium batteries, comprising, by mass parts, 40-75 parts lithium salt, 10-30 parts crosslinking agent, 5-25 parts nano-sized borosilicate glass fiber and 1-10 parts photoinitiator.

[0036] Preferably, the lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluoroborate, lithium dioxalate borate, and lithium difluorooxalate borate.

[0037] Preferably, the crosslinking agent is one or more of methyl methacrylate, acrylonitrile, vinylidene fluoride, and ethylene glycol.

[0038] Preferably, the nano-sized borosilicate glass fiber comprises 70-80 parts silicon dioxide, 6-15 parts boron oxide, 4-10 parts sodium oxide, 0-5 parts aluminum oxide, 0-2 parts calcium oxide, and 0-2 parts barium oxide, wherein the nano-sized borosilicate glass fiber has a particle size of 20-1000 nm.

[0039] Preferably, the photoinitiator is one or more of the following: 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, isopropylthioxanthone, benzophenone, methyl o-benzoylbenzoate, diphenyliodonium hexafluorophosphate, and 4-methylbenzophenone.

[0040] Secondly, embodiments of this application provide a method for preparing a solid electrolyte for lithium batteries, comprising the following steps:

[0041] Lithium salt, crosslinking agent, nano-sized borosilicate glass fiber, and photoinitiator are added to a solvent and stirred to disperse them evenly to obtain a precursor solution.

[0042] The precursor solution was uniformly coated onto the substrate and cured with ultraviolet light to obtain a solid electrolyte.

[0043] Preferably, the solvent is a mixed solution of 1,3-dioxolane and 1,2-dimethoxyethane, wherein the volume ratio of 1,3-dioxolane and 1,2-dimethoxyethane is 1:1, or a mixed solution of ethylene carbonate, diethyl carbonate and dimethyl carbonate, wherein the volume ratio of ethylene carbonate, diethyl carbonate and dimethyl carbonate is 1:1:1; the mass ratio of lithium salt to solvent is (40~75):(22~65).

[0044] Preferably, the stirring speed is 300~800 rpm.

[0045] Preferably, the coating thickness of the precursor solution is 50~200μm, and the ultraviolet curing conditions are: the wavelength of the ultraviolet light is 320nm, and the curing time is 2~20min.

[0046] Thirdly, embodiments of this application provide a lithium battery including the aforementioned solid electrolyte.

[0047] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0048] I. Preparation Method

[0049] Example 1

[0050] (1) 23.45 g of lithium bis(trifluoromethanesulfonyl)imide, 16.2 g of methyl methacrylate, 12.96 g of nano-sized borosilicate glass fiber with a particle size of 20 nm and 0.54 g of 2-hydroxy-2-methyl-1-phenylpropanone were added to a mixed solution of 1,3-dioxolane and 1,2-dimethoxyethane in a volume ratio of 1:1 in 50 mL. The mixture was magnetically stirred at 600 rpm for 12 h to obtain a solid electrolyte precursor solution.

[0051] The nano-sized borosilicate glass fibers were purchased from Corker, model ECP, with a particle size of 20~1000nm. The raw materials for the nano-sized borosilicate glass fibers are 80 wt% silica, 12 wt% boron oxide, 5 wt% sodium oxide, 1 wt% alumina, and 2 wt% calcium oxide. The raw materials are obtained through mixing, melting, fiber forming, and nano-sizing.

[0052] (2) The precursor solution in (1) was coated onto the substrate with a 50 μm gap and irradiated under ultraviolet light at a wavelength of 320 nm for 2 min to obtain the novel solid electrolyte.

[0053] Example 2

[0054] The other conditions are the same as in Example 1, except that the amount of lithium bis(trifluoromethanesulfonyl)imide added in step (1) is adjusted to 12.15 g.

[0055] Example 3

[0056] The other conditions are the same as in Example 1, except that the amount of lithium bis(trifluoromethanesulfonyl)imide added in step (1) is adjusted to 48.6 g.

[0057] Example 4

[0058] The other conditions are the same as in Example 1, except that the amount of methyl methacrylate added in step (1) is adjusted to 2.5 g.

[0059] Example 5

[0060] The other conditions are the same as in Example 1, except that the amount of methyl methacrylate added in step (1) is adjusted to 29.8 g.

[0061] Example 6

[0062] The other conditions are the same as in Example 1, except that the amount of nano-sized borosilicate glass fiber added in step (1) is adjusted to 1.6 g.

[0063] Example 7

[0064] The other conditions are the same as in Example 1, except that the amount of nano-sized borosilicate glass fiber added in step (1) is adjusted to 25.9 g.

[0065] Example 8

[0066] The other conditions are the same as in Example 1, except that the amount of 2-hydroxy-2-methyl-1-phenylpropanone added in step (1) is adjusted to 0.27 g.

[0067] Example 8

[0068] The other conditions are the same as in Example 1, except that the amount of 2-hydroxy-2-methyl-1-phenylpropanone added in step (1) is adjusted to 8.7 g.

[0069] Example 9

[0070] The other conditions are the same as in Example 1, except that the particle size of the nano-sized borosilicate glass fiber in step (1) is adjusted to 200 nm.

[0071] Example 10

[0072] The other conditions are the same as in Example 1, except that the gap between the precursor solution coating in step (2) is adjusted to 150 μm.

[0073] Example 11

[0074] The other conditions are the same as in Example 1, except that the UV curing time in step (2) is adjusted to 20 min.

[0075] Example 12

[0076] The other conditions are the same as in Example 1, except that lithium bis(trifluoromethanesulfonyl)imide in step (1) is changed to lithium bis(fluorosulfonyl)imide.

[0077] Example 13

[0078] The other conditions are the same as in Example 1, except that methyl methacrylate in step (1) is replaced with acrylonitrile.

[0079] Example 14

[0080] The other conditions are the same as in Example 1, except that 2-hydroxy-2-methyl-1-phenylpropanone in step (1) is changed to 1-hydroxycyclohexylphenyl methyl ketone.

[0081] Example 15

[0082] The other conditions are the same as in Example 1, except that the mixed solution of 1,3-dioxopentane and 1,2-dimethoxyethane in step (1) with a volume ratio of 1:1 is adjusted to a mixed solution of ethylene carbonate, diethyl carbonate and dimethyl carbonate with a volume ratio of 1:1:1.

[0083] Comparative Example 1

[0084] (1) 23.45 g of lithium bis(trifluoromethanesulfonyl)imide, 16.2 g of methyl methacrylate and 0.54 g of 2-hydroxy-2-methyl-1-phenylpropanone were added to a mixed solution of 1,3-dioxolane and 1,2-dimethoxyethane in a volume ratio of 1:1 in 50 mL. The mixture was magnetically stirred at 600 rpm for 12 h to obtain the precursor solution.

[0085] (2) The 5 mL precursor solution from (1) was coated onto the substrate with a 50 μm gap and irradiated under ultraviolet light at a wavelength of 320 nm for 2 min to obtain a solid electrolyte.

[0086] Comparative Example 2

[0087] (1) Mix 80 wt% silica, 12 wt% boron oxide, 5 wt% sodium oxide, 1 wt% aluminum oxide and 2 wt% calcium oxide to prepare a sol, and add sodium hydroxide solution to adjust the pH of the sol to 8.0. Then heat to 650 ℃ and keep for 8 h to allow the silicate precursor to fully polymerize and form a gel. After drying at 80 ℃ for 12 h, a silicate glass fiber membrane is formed.

[0088] (2) 23.45 g of lithium bis(trifluoromethanesulfonyl)imide, 16.2 g of methyl methacrylate and 0.54 g of 2-hydroxy-2-methyl-1-phenylpropanone were added to a mixed solution of 1,3-dioxolane and 1,2-dimethoxyethane in a volume ratio of 1:1 in 50 mL. The mixture was magnetically stirred at 600 rpm for 12 h to obtain the precursor solution.

[0089] (3) 5 mL of the precursor solution in (2) was poured onto a 0.65 g borosilicate glass fiber membrane with a thickness of 50 μm, and then irradiated under ultraviolet light with a wavelength of 320 nm for 2 min to obtain a solid electrolyte.

[0090] II. Testing Methods

[0091] (1) Electrochemical performance testing, the specific testing process is as follows:

[0092] The battery assembly process is as follows: First, the solid electrolyte prepared according to the method in the examples and comparative examples is cut into circular pieces with a diameter of 19mm. Then, the lithium-sulfur battery is assembled in the order of negative electrode shell, spring sheet, gasket, lithium metal negative electrode, the above-mentioned solid electrolyte, sulfur positive electrode, and positive electrode shell. Except for the different electrolyte composition, the other conditions are completely the same in the assembly process.

[0093] The battery testing process was as follows: After the lithium-sulfur batteries prepared in Examples 1 to 15 and Comparative Examples 1 to 2 were left to stand for 24 hours, they were subjected to charge-discharge cycle tests at 0.5C rate at 60°C.

[0094] (2) Limiting Oxygen Index (LOI) Test: After the sample to be tested is cut and marked according to the standard, it is preheated and the parameters (such as oxygen and nitrogen flow rates) are set using a limiting oxygen index (LOI) tester. After the sample is correctly installed and fixed, the test is started, and the combustion situation is observed and recorded, including time and flame height. Subsequently, the oxygen concentration is gradually adjusted according to the combustion situation until the lowest concentration that can sustain combustion is found, i.e., the limiting oxygen index.

[0095] (3) UL 94 test method: After the Bunsen burner (flame height about 20 mm) is in contact with the center point below the sample for 10 ± 0.5 seconds, the Bunsen burner is removed at a speed of 300 mm / s, at least 150 mm away from the sample, and the first self-ignition time is recorded. After the self-ignition stops, a second combustion is immediately carried out, and after burning for 10 ± 0.5 seconds, the Bunsen burner is removed, and the second self-ignition time and the incandescent time after the flame is extinguished are recorded.

[0096] III. Analysis of Test Results for Each Embodiment and Comparative Example

[0097] (1) The electrochemical performance of the solid electrolytes prepared in Examples 1-15 and Comparative Examples 1-2 of the present invention was tested, and the test results are shown in Table 1.

[0098] Table 1. Electrochemical performance test results of solid electrolyte

[0099]

[0100] Based on the test data of Example 1 and Comparative Examples 1-2 in Table 1, and Figures 1-2 As can be seen, the solid electrolyte provided by the present invention can significantly improve the capacity retention rate and average coulombic efficiency of lithium-sulfur batteries. This can be attributed to the fact that the nanoscale borosilicate glass fiber, as an inorganic filler, helps to reduce the crystallinity of the polymer component and increase the amorphous phase region, thereby facilitating the rapid migration of lithium ions.

[0101] Furthermore, the test data from Example 1 and Comparative Example 2, and Figure 1 , Figure 3 As can be seen, nanoscale silicate glass fibers have better flexibility than silicate glass fiber membranes, enabling better contact with the polymer interface, which is beneficial for the rapid conduction of lithium ions and ensures good cycle performance of the battery.

[0102] According to Examples 1-9, it was found that solid electrolytes composed of different contents of lithium salt, crosslinking agent, nano-sized borosilicate glass, and photoinitiator can all alter the cycle performance of lithium-sulfur batteries to varying degrees. According to Examples 10-11, it was found that different nano-sized borosilicate glass particle sizes and different solid electrolyte thicknesses can all change the cycle performance of lithium-sulfur batteries. According to Examples 12-15, it was found that changing the types of lithium salt, crosslinking agent, photoinitiator, and solvent also alters the cycle performance of lithium-sulfur batteries.

[0103] (2) Samples were made from the solid electrolytes obtained in Example 1 and Comparative Example 1. The sample size was 12.5cm×12.5cm×1.3cm. The limiting oxygen index (LOI) and vertical burning test (UL-94) were tested. The test results are shown in Table 2 below.

[0104] Table 2. LOI and UL-94 test data of Comparative Examples 1-2 and Example 1

[0105]

[0106] Based on the Limiting Oxygen Index (LOI) and Vertical Burning Test (UL-94) data in Table 2, it can be seen that Comparative Example 1 is extremely flammable, with an LOI value of 26.5% and no rating in the UL-94 test. After adding the borosilicate glass fiber membrane, its LOI value reached 32.5%, and it obtained a UL-94 test V-1 rating. Then, after adding nano-sized borosilicate glass fiber, the LOI and UL-94 rating of Example 1 were significantly improved, with an LOI value reaching 36.5%, and it successfully obtained a UL-94 test V-0 rating. This indicates that Example 1 has excellent flame retardancy.

[0107] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A solid electrolyte for lithium batteries, characterized in that, By weight, it includes 40-75 parts lithium salt, 10-30 parts crosslinking agent, 5-25 parts nano-sized borosilicate glass fiber and 1-10 parts photoinitiator; The raw materials for the nano-sized borosilicate glass fiber, by mass fraction, include 70-80 parts silicon dioxide, 6-15 parts boron oxide, 4-10 parts sodium oxide, 0-5 parts aluminum oxide, 0-2 parts calcium oxide, and 0-2 parts barium oxide. The raw materials are mixed, melted, shaped into fibers, and nano-sized to obtain nano-sized borosilicate glass fiber.

2. The solid electrolyte for lithium batteries according to claim 1, characterized in that, The lithium salt is one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluoroborate, lithium dioxalate borate, and lithium difluorooxalate borate.

3. The solid electrolyte for lithium batteries according to claim 1, characterized in that, The crosslinking agent is one or more of methyl methacrylate, acrylonitrile, vinylidene fluoride, and ethylene glycol.

4. The solid electrolyte for lithium batteries according to claim 1, characterized in that, The nanoscale borosilicate glass fiber has a particle size of 20~1000nm.

5. The solid electrolyte for lithium batteries according to claim 1, characterized in that, The photoinitiator is one or more of the following: 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-methylthiophenyl]-2-morpholino-1-propanone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, isopropylthioxanthone, benzophenone, methyl o-benzoylbenzoate, diphenyliodonium hexafluorophosphate, and 4-methylbenzophenone.

6. A method for preparing a solid electrolyte for lithium batteries according to any one of claims 1 to 5, characterized in that, Includes the following steps: Lithium salt, crosslinking agent, nano-sized borosilicate glass fiber, and photoinitiator are added to a solvent and stirred to disperse them evenly to obtain a precursor solution. The precursor solution was uniformly coated onto the substrate and cured with ultraviolet light to obtain a solid electrolyte.

7. The method for preparing a solid electrolyte for lithium batteries according to claim 6, characterized in that, The solvent is a mixed solution of 1,3-dioxolane and 1,2-dimethoxyethane, wherein the volume ratio of 1,3-dioxolane and 1,2-dimethoxyethane is 1:1, or a mixed solution of ethylene carbonate, diethyl carbonate and dimethyl carbonate, wherein the volume ratio of ethylene carbonate, diethyl carbonate and dimethyl carbonate is 1:1:1; the mass ratio of lithium salt to solvent is (40~75):(22~65).

8. The method for preparing a solid electrolyte for lithium batteries according to claim 6, characterized in that, The stirring speed is 300~800 rpm.

9. The method for preparing a solid electrolyte for lithium batteries according to claim 6, characterized in that, The coating thickness of the precursor solution is 50~200μm, and the ultraviolet curing conditions are: the wavelength of the ultraviolet light is 320nm, and the curing time is 2~20min.

10. A lithium battery, characterized in that, Includes the solid electrolyte as described in any one of claims 1 to 5.

Images