Solid electrolyte and preparation method and application thereof

Abstract

The invention relates to the field of solid electrolyte, in particular to solid electrolyte as well as a preparation method and application thereof. According to the solid electrolyte provided by the invention, a cross-linking reaction of an oligomer is initiated by a photoinitiator to form a solid electrolyte network structure; and the oligomer is one or more of epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, epoxy resin and organic silicon oligomer. According to the invention, the photoinitiator is added and illumination is combined to initiate the crosslinking reaction of the oligomer, so that the electrolyte slurry forms a solid electrolyte network structure, thereby improving the stability of the solid electrolyte.

Description

Technical Field

[0001] The present invention relates to the field of solid electrolytes, and particularly to a solid electrolyte, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of industries such as portable electronic devices and electric vehicles, the demand for energy storage devices with high energy density and high safety is becoming increasingly urgent. The organic liquid electrolytes used in traditional lithium-ion batteries have safety hazards such as low electrochemical stability, flammability, explosiveness, and easy leakage, which limit their further application. Solid electrolytes have become a research hotspot for next-generation lithium-ion batteries due to their advantages such as high thermal stability, non-flammability, and high safety. However, existing preparation methods of solid electrolytes, such as coating and mold forming, have problems such as difficulty in controlling the shape and thickness, and poor interfacial contact, making it difficult to meet the requirements of complex battery structures.

[0003] Therefore, those skilled in the art are committed to developing a solid electrolyte with excellent thermal stability and safety and a simple preparation method thereof, as well as an application thereof. Summary of the Invention

[0004] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a solid electrolyte with excellent thermal stability and safety and a simple preparation method thereof, as well as an application thereof.

[0005] To achieve the above object, the present invention provides a solid electrolyte, which forms a solid electrolyte network structure by initiating a crosslinking reaction of an oligomer with a photoinitiator;

[0006] The oligomer is one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy resin, and silicone oligomer. The photoinitiator can be: 2-benzyl-2-dimethylamino-1-(4-morpholinobenzylphenyl)butanone, bis(2,6-difluoro-3-(1-pyrrolyl)phenyl)titanocene, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)oxophosphine methylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoyl phenylphosphonate, 2-chlorothioxanthone, 2,4-diethylthioxanthone, (5-p-toluenesulfonyloxyimine-5H-thiophen-2-ylidene)-(4-methoxyphenyl)-acetonitrile, etc. In the prior art, the solid electrolyte generally consists of a base film and a coating material on its surface, and there are multiple steps in production. After the base film is prepared, coating is carried out, which has problems such as difficulty in controlling shape and thickness and poor interface contact, and it is difficult to meet the requirements of complex battery structures. In this patent, by adding a photoinitiator to initiate the cross-linking reaction of the oligomer, the electrolyte slurry forms a solid electrolyte network structure, thereby improving the stability of the solid electrolyte. Secondly, the photoinitiator absorbs radiant energy, undergoes a chemical change after excitation, generates active intermediates with the ability to initiate polymerization, and initiates a polymerization reaction under ultraviolet light irradiation conditions, causing the slurry to solidify and form a shape during the 3D printing process. The oligomer in the material can build up the basic network skeleton of the solid electrolyte after curing and polymerization, affecting the mechanical properties and ionic conductivity of the electrolyte. The two cooperate with each other to enable the internal structure of the electrolyte to form a network structure, and this network structure has the advantages of strong stability and high temperature resistance, so that the present invention has excellent thermal stability and safety.

[0007] Preferably, the present invention further includes a lithium salt, which is the main ion source of the electrolyte. The lithium salt has a significant impact on improving the ionic conductivity and electrochemical stability of the electrolyte. The electrolyte of the present invention forms a three-dimensional network structure through the cross-linking of the oligomer and the monomer in the resin system, and fills the filler with this structure, serving as the carrier for the diffusion of lithium ions in the lithium salt. This structural design effectively promotes the diffusion of lithium ions, thereby improving the ionic conductivity and lithium ion transference number of the battery, and further achieving better electrochemical performance.

[0008] Preferably, it further includes inorganic fillers, and the inorganic fillers are one or more of calcium carbonate, barium sulfate, aluminum silicate, magnesium aluminum silicate, sodium aluminum silicate, silicon dioxide, titanium dioxide, zinc oxide, zirconium oxide, and mica. The addition of the inorganic filler powder forms a stable solid electrolyte structure through cross-linking and curing with the oligomer, which can significantly improve the ionic conductivity of the solid electrolyte, enhance the electrochemical performance of the battery, also enhance the mechanical properties and thermal stability of the electrolyte, and at the same time can affect the ionic conduction path. On the other hand, the significant reduction in the amount of electrolyte used can also improve safety.

[0009] Preferably, the lithium salt is one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium nitrate, and lithium oxalate.

[0010] Preferably, it further includes an inorganic filler. By mass, the weight parts of the photoinitiator are 1 to 10 parts, the weight parts of the lithium salt are 5 to 70 parts, the weight parts of the oligomer are 10 to 90 parts, and the weight parts of the inorganic filler are 10 to 90 parts.

[0011] Preferably, by mass, the weight parts of the photoinitiator are 2 to 5 parts, the weight parts of the lithium salt are 10 to 40 parts, the weight parts of the oligomer are 30 to 70 parts, and the weight parts of the inorganic filler are 45 to 75 parts.

[0012] Preferably, it further includes a diluent, an additive, and a solvent. The diluent adjusts the viscosity of the slurry to make various raw materials more easily dispersed. In order to further accelerate the formation of a network structure, preferably, a reactive diluent is used because they are reactive and can participate in the curing reaction to form a crosslinked network. The diluent can be one or more of 1,6 - hexanediol diacrylate, neopentyl glycol diacrylate, dipropylene glycol diacrylate, N - vinylpyrrolidone (NVP), trimethylolpropane triacrylate, pentaerythritol triacrylate, tripentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate, and 3,3 - [oxybis(methylene)]bis[3 - ethyl]oxetane. The additive improves the processing performance of the slurry and can be added as needed to improve related physical properties such as leveling property and wettability. The optional range of the additive includes defoaming agents, wetting and dispersing agents, inhibitors, light - blocking agents, matting agents, etc. The solvent is used to dilute the slurry, and generally any organic solvent can be used, such as methanol, ethanol, N - methyl - 2 - pyrrolidone (NMP), dichloromethane, acetone, n - butanol, acetonitrile, ethyl acetate, N,N - dimethylformamide (DMF).

[0013] The present invention also provides a preparation method of a solid electrolyte, which is characterized by including the following steps:

[0014] 1) Mix the photoinitiator and the oligomer evenly by stirring to form a photosensitive resin;

[0015] 2) Add the lithium salt and mix and stir until completely dissolved;

[0016] 3) Add the inorganic filler to make the inorganic filler evenly dispersed;

[0017] 4) Pour it into a photo - curable 3D printing cartridge and print it into a preset shape.

[0018] The photoinitiator generates photocuring polymerization through the ultraviolet light irradiation of a photocuring 3D printer to form a solid electrolyte network structure. The 3D printer can accurately control the printing parameters to flexibly adjust the shape and thickness of the solid electrolyte, while improving the ionic conductivity and interfacial compatibility of the solid electrolyte.

[0019] Preferably, in the step 1), a diluent is added and mixed and stirred to control the system viscosity of the photosensitive resin at 30-1000 Pa·s; in the step 2), an auxiliary agent is added and stirred together; in the step 3), a solvent is added for dilution.

[0020] The present invention also provides an application of the solid electrolyte as described above in a separator, a lithium battery or an automobile.

[0021] The beneficial effects of the present invention are as follows: The network structure can improve the stability of the solid electrolyte; the addition of inorganic fillers significantly improves the ionic conductivity of the solid electrolyte, enhances the electrochemical performance of the battery, and further greatly improves the thermal stability of the solid electrolyte. On the other hand, the significant reduction in the amount of electrolyte used can also improve the safety. Through the 3D printing technology, the shape and thickness of the solid electrolyte can be accurately controlled to meet the requirements of different application scenarios. The 3D printing technology makes the contact between the electrolyte and the electrode closer by designing a porous structure, reduces the interfacial impedance, and improves the cycle stability and rate performance of the battery. At the same time, the present invention can simplify the manufacturing process, reduce the manufacturing cost and time, and improve the production efficiency. Description of the Drawings

[0022] Figure 1 It is a state diagram of Example 3 of the present invention, a PP separator, and a ceramic-coated separator at different temperatures. Detailed Embodiments

[0023] The present invention will be further described below with reference to the drawings and embodiments.

[0024] Examples 1-5 are for the preparation of a solid electrolyte of the present invention.

[0025] The preparation of the solid electrolytes in Examples 1-5 is carried out according to the following steps, and the difference lies in the specific selection and dosage of various raw materials. The preparation steps specifically include:

[0026] 1) Mix the photoinitiator and oligomer and stir until completely dissolved to form a photosensitive resin. In this step, to ensure that the system viscosity is between 30 - 1000 Pa·s, a diluent can be added if necessary. In the present invention, the crosslinking reaction of the oligomer is initiated by the photoinitiator, and a solid electrolyte network structure can be formed under ultraviolet light irradiation. Specifically, it can be achieved through the photocuring 3D printing technology. By initiating the crosslinking reaction of the oligomer and the like with ultraviolet light, the material is changed from a liquid state to a solid state, and the crosslinking curing is completed to form a three-dimensional network structure of the electrolyte, which has high stability.

[0027] In step 1), the stirring speed is controlled below 800 r / min until completely dissolved. Stirring too fast will cause heat generation, which may lead to thermal polymerization of the photoinitiator, thus affecting the material properties. In step 1), after the photoinitiator and oligomer (or active diluent, added according to the system viscosity requirements) are stirred to form a photosensitive resin, the system viscosity of the photosensitive resin should be controlled between 30 - 1000 Pa·s. In this application, the system viscosity should be strictly controlled. The viscosity of the slurry will affect the fluidity. A lower viscosity is beneficial to improving the printing rate and the accuracy of the product. Too high viscosity will affect the surface quality and detail performance of the printed parts. Resins with lower viscosity can cure faster, improving the printing efficiency. However, too low viscosity will cause an increase in the shrinkage rate of the cured product, affecting the forming accuracy. In addition, if the viscosity is too low, it cannot provide better mechanical properties of the material. Only when the slurry viscosity is well controlled can the material utilization rate approach 100%, improving the material usage efficiency. The molecular structure of the photosensitive resin and the crosslinking density after curing determine the mechanical properties of the printed component and the thermal decomposition characteristics during the debinding process, which is also related to the viscosity of the slurry. By optimizing the viscosity of the slurry, material waste can be reduced, costs can be lowered, and economic benefits can be improved.

[0028] Under the irradiation of ultraviolet light, the photoinitiator absorbs the ultraviolet light energy to promote the formation of active free radicals of the oligomer and monomer in the photocuring 3D printing resin system, resulting in the cleavage and polymerization of the carbon-carbon double bond functional groups in the resin system. The oligomer or monomer in the resin system is active, causing them to crosslink with each other to form a three-dimensional network structure, and the photocuring 3D printing material changes from a liquid state to a solid state, completing the crosslinking curing.

[0029] The photoinitiator can be one or more of 2-phenylbenzyl-2-dimethylamino-1-(4-morpholinobenzylphenyl)butanone (369), bis(2,6-difluoro-3-(1-pyrrolyl)phenyl)titanocene (784), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphinate (TPO-L), 2-chlorothioxanthone or 2-chlorothioxanthone (CTX), 2,4-diethylthioxanthone (DETX), (5-toluenesulfonyloxyimino-5H-thiophen-2-ylidene)-(4-methoxyphenyl)-acetonitrile, etc.

[0030] During specific implementation of manufacturing, products from market manufacturers can all be selected. For example: Macklin 369, B835380, 97%; Yuanye Irgacure 784, Y46976, purity ≥98%; Macklin 819, P831909, 98%; Aladdin TPO, T107643, 97%; Aladdin TPO-L, E186856, 98%; Macklin CTX, C804525, 98%; Aladdin DETX, D154567, purity ≥98%; (5-toluenesulfonyloxyimino-5H-thiophen-2-ylidene)-(4-methoxyphenyl)-acetonitrile, Hubei Gurun, GR-PAG-2, ≥98%.

[0031] The oligomer is one or more of epoxy acrylate (EA), polyurethane acrylate (PUA), polyester acrylate (PEA), polyether acrylate, epoxy resin, and silicone oligomer. During specific implementation of manufacturing, products from market manufacturers can all be selected. For example: Epoxy acrylate can use Jiangsu KaiLing RuiYang, RY1305, Shenzhen Zheyi, 713, etc. Polyurethane acrylate can use Sartomer, CN972, Zhongshan Qianyou, UV2100, etc. Polyester acrylate can use Arkema, 5429 or Qitai, SP284; Polyether acrylate can use Huntsman, EB83 or BASF, PO9026F; Epoxy resin can use Dow Chemical, UVR6105 or UVR6100 or UVR6216 or BASF, LR8765; Silicone acrylate can use Guangdong Boxing, B-8116 or Shenzhen Zhongbang, UVG-510.

[0032] 2) Add lithium salt and mix and stir until completely dissolved. In order to improve the processing performance of the slurry, in this step, additives can be added according to the situation of the slurry. The lithium salt is the main ion source of the electrolyte. The oligomer provides a carrier for the dispersion of the lithium salt. At the same time, the ions of the lithium salt form a conduction channel in the polymer network, affecting the ionic conductivity and electrochemical stability of the electrolyte.

[0033] The lithium salt is one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium nitrate (LiNO3), lithium oxalate (LiC2O4), etc. In other embodiments, other lithium salts can also be used. During specific implementation and manufacturing, products from market manufacturers can all be selected. For example, for LiPF6, it is from Macklin, L822100, 99.5%; for LiBF4, it is from Aladdin, L118406, 99.99%; for LiCF3SO3, it is from Aladdin, L398970, ≥99.5%; for LiTFSI, it is from Macklin, L864322, >98%; for LiC2O4, it is from Aladdin, L401056, 99.9%. The diluent can adjust the viscosity of the slurry, making it easier for the inorganic filler to disperse. At the same time, they are reactive and assist in participating in the curing reaction to more quickly form a crosslinked network. The diluent can be one or more of 1,6 - hexanediol diacrylate (HDDA), neopentyl glycol diacrylate (NPGDA), dipropylene glycol diacrylate (DPGDA), N - vinylpyrrolidone (NVP), trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), dipentaerythritol pentaacrylate (DPPA), dipentaerythritol hexaacrylate (DPHA), 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate, 3,3 - [oxybis(methylene)]bis[3 - ethyl]oxetane. Specific brands on the market can all be used. For example, for HDDA, the product GM62B00 from Guojing Chemistry can be used; for NPGDA, the product SM625 from Jiangsu Sanmu can be used; for DPGDA, the product R203 from Jiangsu KaiLing RuiYang can be used; for NVP, the product from Aladdin, V106155, 99% can be used; for TMPTA, the product SR351 from Sartomer can be used; for ETA, the product M340 from Changxing can be used; for DPPA, the product 4399 from Arkema can be used; for DPHA, the product M400 from Toagosei can be used; for 3,4 - epoxycyclohexylmethyl 3',4' - epoxycyclohexanecarboxylate, the product TTA21 from Taitel New Material Technology Company can be used; for 3,3 - [oxybis(methylene)]bis[3 - ethyl]oxetane, the product GR - OXT - 3, ≥98% from Hubei Gurun Technology Company can be used.

[0034] In the present invention, the auxiliary agents used may include: defoamers, which may be low-grade alcohols, organic modified compounds, mineral oils, organic polymers, silicone resins, and other categories of defoamers; wetting and dispersing agents may be natural polymers, synthetic polymers, polyvalent carboxylic acids, silicon-based coupling agents, and titanium-based coupling agents; leveling agents may be polyacrylates, silicone resins, and fluorosurfactants; polymerization inhibitors, which may be p-hydroxyanisole, hydroquinone, and the like, matting agents, and various auxiliary agents may be added one or more as needed. Of course, one or more of the same auxiliary agents may also be selected. When implementing the manufacturing, all products of market manufacturers may be selected, such as: defoamers may be Deqian, 2700, 3100, or 5300; Digo, Airex986; BYK-055, BYK-057, or BYK-088; Efka, Efka2720, or Efka2721. The leveling agent is Deqian 432 or TROY Troysol S366. The dispersant is BYK DISPERBYK-168 or DISPERBYK-2158; the matting agent is BYK Ceraflour 950 or Ceraflour 1000. The matting agent is Deqian 11MW-611 or MW-612 or Grace Rad 2005 or Rad 2105.

[0035] Of course, if time permits, no additives may be added.

[0036] 3) Adding inorganic fillers to make the inorganic fillers evenly dispersed. In this step, a solvent can be added to dilute it according to the dispersion situation to make it easier to disperse. The inorganic filler is one or more of calcium carbonate, barium sulfate, aluminum silicate, magnesium aluminum silicate, sodium aluminum silicate, silicon dioxide, titanium dioxide, zinc oxide, zirconium oxide, and mica. If no solvent is added, the dispersion efficiency will be affected.

[0037] When the manufacturing is carried out specifically, products from manufacturers on the market can be selected, such as: calcium carbonate is McLean, C886288, with a particle size of 50nm; barium sulfate is Aladdin, B112377, 99% 2μm; aluminum silicate is McLean, D919802; magnesium aluminum silicate is McLean, M875683; sodium aluminum silicate is McLean, S832352; silicon dioxide is Aladdin, S433675, 3μm; titanium dioxide is Aladdin, T476464, <5μm; zinc oxide is Aladdin, Z112849, 99.8% 50nm; zirconium oxide is McLean, Z820679, 99.99% 50nm; mica is McLean, D875288, 1μm.

[0038] In this step, adding a solvent can improve the stirring efficiency, and finally the viscosity of the system is between 2000-8000 mPa·s to form a composite solid electrolyte slurry.

[0039] The solvent can be one or more of methanol, ethanol, N-methyl-2-pyrrolidone (NMP), dichloromethane, acetone, n-butanol, acetonitrile, ethyl acetate, N,N-dimethylformamide (DMF).

[0040] 4) Pour the slurry into a vat for stereolithography 3D printing and print it into a preset shape.

[0041] In this step, the 3D printing uses a printing technology based on digital light processing (DLP). Of course, in other embodiments, other stereolithography 3D printing technologies such as stereolithography (SLA) and laser cladding deposition technology (LCD) can also be used. In this embodiment, a light source in the near-ultraviolet (382 - 400 nm) or ultraviolet light band (360 - 371 nm) is used, and the printing parameters are controlled to print the slurry into a preset shape. In the embodiments of the present invention, the exposure time is 2 - 10 s, and the light intensity is generally 1 - 20 mW / cm -2 .

[0042] Through the DLP 3D printing technology, the present invention realizes precise control of the shape and thickness of the solid electrolyte, meeting the requirements of different application scenarios. The 3D printing technology makes the contact between the electrolyte and the electrode closer by designing a porous structure, reduces the interfacial impedance, and improves the cycle stability and rate performance of the battery. Printer manufacturers such as EnvisionTEC, Formlabs, ANYCUBIC, etc. can be selected.

[0043] The component selections of Examples 1 - 5 are shown in Table 1, and the dosages of each component in Examples 1 - 5 are shown in Table 2

[0044]

[0045] The dosage unit of each component in Table 2 is g.

[0046]

[0047] In Examples 1 - 5, when the same type of raw materials are composed of different specific substances, they are mixed in a ratio of 50% each. Of course, other ratios can also be used, and the present invention does not make any limitations. In the present invention, the main function of the solvent is to control the viscosity of the slurry, so that the system viscosity is within 2000 - 8000 mPa·s, and a composite solid electrolyte slurry can be formed.

[0048] Comparing the solid electrolyte produced by the present invention with that produced by the traditional process, there are the following advantages, as shown in Table 3:

[0049] Table 3

[0050]

[0051] The present invention also provides an application of the above-mentioned solid electrolyte in a separator, a lithium battery, or an automobile.

[0052] The solid electrolyte of the present invention can be used as a lithium battery separator, and then used in the production of lithium batteries or electric-powered vehicles.

[0053] In order to further illustrate that the present invention has extremely high thermal stability, in this application, the solid electrolyte prepared in Example 3 was used for high-temperature tests. And PP separators and ceramic-coated separators were used for comparison. In this test, an oven was used for gradient heating to gradually increase the temperature of the test samples, and photos were taken to observe and record the states of the three solid electrolytes at different temperatures. The photo results are as Figure 1 shown. Figure 1 In the figure, PP represents the state of the PP separator at different temperatures, ceramic-coated represents the state of the ceramic-coated separator at different temperatures, and printed represents the state of the solid electrolyte prepared in Example 3 of this application at different temperatures.

[0054] It can be seen through Figure 1 that the traditional commercial PP separator undergoes deformation and decomposition at 140 °C. The deformation of the commercial separator with ceramic coating decreases at 140 °C, but obvious deformation occurs at 160 °C, indicating that the ceramic coating is beneficial to increasing thermal stability to a certain extent, but the performance still needs to be improved. However, when using the material of this application, it can be seen that the morphology can still be kept intact up to 255 °C.

[0055] Through the comparison of the thermal stability between the traditional commercial separator and the electrolyte separator of this application, it shows that the thermal stability of the solid electrolyte separator in this application is significantly improved compared with the traditional technology, and the thermal stability is excellent.

[0056] At the same time, it can also be known from the Figure 1 comparison that the present invention has extremely high safety when applied to batteries: First, the printed solid electrolyte significantly increases the thermal stability due to the mixing of inorganic fillers, thereby improving electrical safety; Second, in this application, only lithium salt needs to be added during the preparation of the separator, which can further increase the ionic conductivity, provide ion channels, and promote the conduction of lithium ions. Therefore, compared with the previous two commercial separators, less electrolyte is required, thus significantly reducing the amount of traditional liquid electrolyte. By reducing the amount of electrolyte, the internal pressure of the battery and the gas generated by the chemical reaction of the liquid electrolyte during charge and discharge in the battery are reduced, further reducing the risk of battery leakage, expansion, and even explosion.

[0057] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the existing technology should be within the protection scope determined by the claims.

Claims

1. A solid electrolyte, characterized in that: A cross-linking reaction of the oligomer is initiated by a photoinitiator to form a solid electrolyte network structure; The oligomer is one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, polyether acrylate, epoxy resin, and silicone oligomer.

2. The solid electrolyte according to claim 1, characterized in that: Also included are lithium salts, which are the main ion source for the electrolyte.

3. The solid electrolyte according to claim 1, characterized in that: It also includes an inorganic filler, which is one or more of calcium carbonate, barium sulfate, aluminum silicate, magnesium aluminum silicate, sodium aluminum silicate, silicon dioxide, titanium dioxide, zinc oxide, zirconium oxide, and mica.

4. The solid electrolyte according to claim 2, characterized in that: The lithium salt is one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bistrifluoromethanesulfonamide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium nitrate, and lithium oxalate.

5. The solid electrolyte according to claim 2, characterized in that: It also includes inorganic filler. By mass, the weight of the photoinitiator is 1 to 10 parts, the weight of the lithium salt is 5 to 70 parts, the weight of the oligomer is 10 to 90 parts, and the weight of the inorganic filler is 10 to 90 parts.

6. The solid electrolyte according to claim 5, characterized in that: Based on mass, the weight portion of the photoinitiator is 2 to 5 parts, the weight portion of the lithium salt is 10 to 40 parts, the weight portion of the oligomer is 30 to 70 parts, and the weight portion of the inorganic filler is 45 to 75 parts.

7. The solid electrolyte according to claim 1, characterized in that: It also includes diluents, additives and solvents.

8. A method for preparing a solid electrolyte, characterized in that: The steps include: 1) mixing and stirring the photoinitiator and the oligomer to form a photosensitive resin; 2) Add lithium salt and mix and stir until completely dissolved; 3) Adding inorganic fillers to make the inorganic fillers evenly dispersed; 4) Pour into the light-curing 3D printing material box and print into a preset shape.

9. The method for preparing a solid electrolyte as claimed in claim 8, characterized in that: In the step 1), a diluent is added and mixed and stirred to control the system viscosity of the photosensitive resin to be 30-1000 Pa·s; in the step 2), an auxiliary agent is added and mixed; in the step 3), a solvent is added for dilution.

10. Use of the solid electrolyte according to any one of claims 1 to 7 in a diaphragm, a lithium battery or an automobile.

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