A modified llzo-based solid-state electrolyte membrane and a method for preparing the same

Abstract

The application discloses a modified LLZO-based solid electrolyte film and a preparation method thereof, and belongs to the technical field of solid electrolytes, and comprises the following preparation raw materials in mass parts: 4-15 parts of modified LLZO powder, 0.4-2.4 parts of calcined diatomite, 5-20 parts of a prepolymer, 0.1-2 parts of a photoinitiator, 0.5-5 parts of an active diluent and 25-60 parts of a solvent; preferably, the modified LLZO-based solid electrolyte film comprises the following mass parts: 4-10 parts of modified LLZO powder, 0.4-1.5 parts of calcined diatomite, 8-15 parts of a prepolymer, 0.2-0.5 parts of a photoinitiator, 0.8-2 parts of an active diluent and 30-50 parts of a solvent; the modifier of the modified LLZO powder is tartaric acid and phosphoric acid; and the prepolymer comprises a crosslinked matrix resin, an active dilution monomer and a thermoplastic polymer. The modified LLZO-based solid electrolyte film has good mechanical properties and ionic conductivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid electrolyte, and particularly relates to a modified LLZO-based solid electrolyte film and a preparation method thereof. BACKGROUND

[0002] The solid electrolyte for lithium batteries mainly includes inorganic ceramic electrolyte and solid polymer electrolyte. The solid polymer electrolyte has the advantages of simple preparation method, good ductility and flexibility, good film forming performance, and good electrode-electrolyte interface contact, but has obvious defects such as poor mechanical performance and low ion conductivity at room temperature. For example, the ion conduction of the polyethylene oxide (PEO) system depends on the chain segment movement in the amorphous phase of PEO to realize Li + migration. The proportion of the amorphous phase is small at room temperature, resulting in low ion conductivity. Moreover, the electrochemical window of the PEO solid polymer electrolyte is relatively narrow, which is difficult to match the high-voltage positive electrode material, and the effect of improving the energy density of the solid-state battery is limited, and the solid-state battery needs to work at a relatively high temperature.

[0003] In order to balance the high ion conductivity of inorganic solid electrolyte and the flexibility of solid polymer electrolyte, the inorganic filler is added to the polymer electrolyte, and the development of organic / inorganic composite solid electrolyte becomes a key breakthrough. However, the mechanical strength and stability of the existing composite solid electrolyte cannot fully meet the needs of long cycle stable operation of the solid-state battery. SUMMARY

[0004] The application provides a modified LLZO-based solid electrolyte film and a preparation method thereof to overcome the above technical problems. The modified LLZO-based solid electrolyte film has good mechanical performance and ion conductivity, and therefore, the lithium battery composed of the modified LLZO-based solid electrolyte film has high initial efficiency and high cycle stability.

[0005] The application solves the above technical problems through the following technical solutions.

[0006] The application discloses a modified LLZO-based solid electrolyte film, which comprises the following preparation raw materials in mass parts: 4-15 parts of modified LLZO powder, 0.4-2.4 parts of calcined diatomite, 5-20 parts of a prepolymer, 0.1-2 parts of a photoinitiator, 0.5-5 parts of an active diluent, and 25-60 parts of a solvent; preferably, the modified LLZO-based solid electrolyte film comprises the following mass parts: 4-10 parts of modified LLZO powder, 0.4-1.5 parts of calcined diatomite, 8-15 parts of a prepolymer, 0.2-0.5 parts of a photoinitiator, 0.8-2 parts of an active diluent, and 30-50 parts of a solvent.

[0007] The modifier of the modified LLZO powder is tartaric acid and phosphoric acid;

[0008] The prepolymer comprises a cross-linking matrix resin, an active diluent monomer, and a thermoplastic polymer.

[0009] According to some embodiments of the present application, the mass ratio of the LLZO powder, the tartaric acid, and the phosphoric acid is 100:80-160:20-60, preferably 100:100-150:25-50. In this way, the phosphoric acid treatment can form Li-PO4 bonds on the surface of the LLZO, so that part of the S 2- The LLZO is replaced or generates a phosphate glass, thereby reducing the surface energy and constructing a chemical-mechanically stable, ion-conductive, and electronically insulating interface film. In order to obtain a dense and uniform phosphate coating layer, tartaric acid is introduced as an auxiliary agent. The multi-hydroxyl and multi-carboxyl structures of the tartaric acid can be combined with the metal ions on the surface of the LLZO through coordination to form an organic coating layer. This layer not only acts as a surfactant to reduce the interfacial tension, but also serves as a morphology template to induce uniform nucleation of the phosphate, thereby achieving a dense modification and coating of the surface of the LLZO.

[0010] According to some embodiments of the present application, the mass ratio of the cross-linking matrix resin, the active diluent monomer, and the thermoplastic polymer is 100:70-130:3-20; for example, the mass ratio of the cross-linking matrix resin, the active diluent monomer, and the thermoplastic polymer is 50:50:3. In this way, the cross-linking matrix resin provides a flexible skeleton and interfacial adhesion, the active diluent monomer can adjust the viscosity and appropriately increase the mechanical strength, and the thermoplastic polymer realizes efficient curing of long waves and also endows the electrolyte membrane with certain flexibility and processability. In addition, the polar groups in the molecular chain of the thermoplastic polymer can interact with lithium salts, thereby promoting ion conduction. Therefore, the prepolymer has good mechanical properties, processability, and ion conduction performance.

[0011] According to some embodiments of the present application, the cross-linking matrix resin is polyurethane acrylate (PUA), epoxy acrylate (EA), or polyester acrylate (PEA); preferably, the cross-linking matrix resin is polyurethane acrylate.

[0012] According to some embodiments of the present application, the active diluent monomer is isobornyl acrylate (IBOA, CAS No. 5888-33-5), tert-butyl acrylate (CAS No. 1663-39-4), 2-methoxyethyl acrylate (CAS No. 3121-61-7), or 2,2,3,4,4,4-hexafluorobutyl acrylate (CAS No. 54052-90-3); preferably, the active diluent monomer is isobornyl acrylate.

[0013] According to some embodiments of the present application, the thermoplastic polymer is thermoplastic polyolefin (TPO) or polyethylene oxide (PEO); preferably, the thermoplastic polymer is thermoplastic polyolefin.

[0014] According to some embodiments of the present invention, the composition of the LLZO powder is Li7La3Zr2O. 12 .

[0015] According to some embodiments of the present invention, the D50 of the LLZO powder is 250~350nm.

[0016] According to some embodiments of the present invention, the reactive diluent is at least one of BYK111, BYK-348, BYK-410, tegorad 2300, and EFKA-3777;

[0017] According to some embodiments of the present invention, the solvent is at least one selected from ethanol, n-propanol, isopropanol, ethylene glycol monomethyl ether, ethyl acetate, and methyl isobutyl ketone.

[0018] According to some embodiments of the present invention, the photoinitiator is at least one of 1-HCPK (1-hydroxycyclohexylphenyl ketone, CAS No.: 947-19-3), photoinitiator 2959 (CAS No.: 106797-53-9), photoinitiator 819 (CAS No.: 162881-26-7), and photoinitiator 907 (CAS No.: 71868-10-5).

[0019] This invention also discloses a method for preparing a modified LLZO-based solid electrolyte membrane, characterized by comprising the following steps:

[0020] S1.LLZO powder was modified with a modifier to obtain modified LLZO powder;

[0021] S2. The raw materials for preparing the modified LLZO-based solid electrolyte membrane are mixed according to the required proportions to obtain a slurry;

[0022] S3. After the slurry is cast and molded, it is dried, cured, and then sintered to obtain a modified LLZO-based solid electrolyte membrane.

[0023] In S1, the modification step involves dissolving tartaric acid in ethanol, adding LLZO powder, and finally adding phosphoric acid.

[0024] In S1, the modified material is washed with ethanol until neutral and then vacuum dried.

[0025] In S2, the mixing sequence is as follows: calcined diatomaceous earth is dissolved in a solvent, then modified LLZO powder is added, followed by the prepolymer and photoinitiator, and finally the reactive diluent is added and mixed.

[0026] In S3, the thickness of the film formed by casting is 15~35μm, preferably 20~30μm.

[0027] In S3, the cast film is dried at 50~70℃ for 8~15 minutes after casting.

[0028] In S3, the casting process is carried out under an inert atmosphere.

[0029] In S3, the drying method can be vacuum drying, hot air drying, or infrared heating drying; the drying temperature is 45~90℃.

[0030] In S3, the curing method is ultraviolet curing.

[0031] In S3, the wavelength of the photocuring is 360~400nm, and the intensity of the photocuring is 20~30mW / cm². 2 The photocuring time is 10~25 min.

[0032] In S3, the sintering process is carried out at 150~300℃ for 1~4h, then at 400~600℃ for 2~8h, and finally at 800~1200℃ for 3~10h.

[0033] Preferably, the sintering process involves holding the material at 180-250°C for 1.5-2.5 hours, then at 450-550°C for 3-6 hours, and finally at 900-1100°C for 5-8 hours.

[0034] In S3, the sintering is carried out under a protective atmosphere, specifically in a nitrogen or argon atmosphere.

[0035] In S3, the heating rate during the sintering process is 2~5℃ / min, preferably 3~4℃ / min.

[0036] The present invention also discloses a lithium battery comprising the aforementioned modified LLZO-based solid electrolyte membrane or the modified LLZO-based solid electrolyte membrane prepared by the aforementioned preparation method.

[0037] According to some embodiments of the present invention, the lithium battery has an initial efficiency of ≥80%, preferably ≥85%, and more preferably 88~91%.

[0038] According to some embodiments of the present invention, the capacity retention rate of the lithium battery after 100 cycles is ≥90%, preferably ≥93%, and more preferably 94~97%.

[0039] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] 1. This invention modifies the surface of LLZO powder with tartaric acid and phosphoric acid, optimizing its surface chemical properties and dispersibility, constructing a continuous ion conduction pathway, and significantly improving the ion transference number. Simultaneously, by utilizing the coordination effect between the thermoplastic polymer and lithium salt in a specific prepolymer system, the dissociation and transport efficiency of the lithium salt are enhanced. The synergistic effect of these two factors results in a breakthrough improvement in the ionic conductivity of the composite electrolyte membrane.

[0042] 2. This invention uses a cross-linked matrix resin as a framework to provide basic mechanical support, and introduces calcined diatomaceous earth as a physical reinforcing filler. Its uniform dispersion within the polymer matrix significantly improves the tensile strength of the membrane; the flexible segments of the thermoplastic polymer impart excellent flexibility to the electrolyte membrane. Through the synergistic effect of these three elements, the membrane material maintains high flexibility while also exhibiting high tensile strength, effectively suppressing structural damage during battery charging and discharging and extending its service life. Furthermore, the porous structure of the calcined diatomaceous earth further promotes the uniform dispersion of lithium salts and enhances the stability of ion conduction.

[0043] 3. This invention precisely controls everything from the raw material mixing sequence to the temperature, time, and conditions at each stage. For example, a specific LLZO powder modification process ensures optimized performance; a strict mixing sequence guarantees uniform dispersion of each component, preventing agglomeration; and precisely controlled casting, drying, curing, and sintering conditions enable the composite electrolyte membrane to form an ideal microstructure, such as suitable pore size distribution, crosslinking density, and crystallinity. Attached Figure Description

[0044] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0045] Figure 1 The image shows a SEM image of the modified LLZO-based solid electrolyte membrane prepared in Example 1.

[0046] Figure 2 This is a SEM image of the modified LLZO-based solid electrolyte membrane prepared in Example 2.

[0047] Figure 3 This is a SEM image of the modified LLZO-based solid electrolyte membrane prepared in Example 5.

[0048] Figure 4 SEM image of the modified LLZO-based solid electrolyte membrane prepared for Comparative Example 2. Detailed Implementation

[0049] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0050] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0051] The raw material information used in the following examples is as follows:

[0052] LLZO powder was purchased from Changsha Institute of Mining and Metallurgy, and its D50 was 300 nm.

[0053] Calcined diatomite was purchased from Lingshou County Shunbo Mineral Products Processing Plant and Shanghai Fantanxi Biochemical Technology Co., Ltd., with a pore size of 50~100 nm and a particle size of 325 mesh.

[0054] The diatomite was purchased from Shunbo Mineral Products Processing Plant in Lingshou County. Its particle size was 325 mesh. The diatomite was not calcined.

[0055] Polyurethane acrylate (PUA) was purchased from Ruisheng New Materials RU-2246;

[0056] Thermoplastic polyolefin (TPO) was purchased from Hangzhou Gaofu New Materials Co., Ltd. as TPO-3M;

[0057] This includes, but is not limited to, the models from the above manufacturers.

[0058] Example 1

[0059] 1. The modified LLZO-based solid electrolyte membrane of this embodiment is composed of the following raw materials by weight: 10 parts modified LLZO powder, 0.5 parts calcined diatomaceous earth, 10.3 parts prepolymer, 0.3 parts photoinitiator (1-HCPK), 1 part reactive diluent (BYK-111) and 50 parts solvent (ethanol).

[0060] In this embodiment, the mass ratio of LLZO powder: tartaric acid: phosphoric acid (85% phosphoric acid) in the modified LLZO powder is 100:120:37.5.

[0061] The prepolymer in this embodiment consists of 5 parts PUA, 5 parts IBOA, and 0.3 parts TPO;

[0062] 2. The preparation method of the modified LLZO-based solid electrolyte membrane in this embodiment is as follows:

[0063] S1. Preparation of modified LLZO powder:

[0064] Tartaric acid was added to ethanol at 500 rpm and stirred at 50°C to dissolve. Then LLZO powder was added and stirred for 4 h, followed by phosphoric acid and stirred for 8 h. After modification, the mixture was centrifuged, washed with anhydrous ethanol until neutral, and vacuum dried at 80°C for 8 h to obtain modified LLZO powder.

[0065] S2. Preparation of slurry:

[0066] According to the above-mentioned proportion of raw materials, calcined diatomaceous earth is first dissolved in solvent, then modified LLZO powder is added and stirred at 600 rpm for 1 hour, then prepolymer and photoinitiator are added and stirred at 600 rpm for 3 hours, and finally reactive diluent is added and ultrasonically dispersed for 30 minutes to obtain slurry.

[0067] S3. Preparation of modified LLZO-based solid electrolyte membrane:

[0068] Under an argon atmosphere, the slurry is cast onto a substrate to form a film with a thickness of 20~30μm, and then dried at 60℃ for 10min to form a cured film.

[0069] The cured film was subjected to UV curing for 15 minutes at a distance of 10 cm from the light source, with a UV wavelength of 365 nm and an intensity of 50.0 mW / cm². 2 ;

[0070] Under an argon atmosphere, the modified LLZO-based solid electrolyte membrane was obtained by heating at a rate of 3℃ / min, holding at 200℃ for 2 hours, then at 500℃ for 4 hours, and finally at 1000℃ for 6 hours. After sintering, the membrane was cooled to room temperature (25℃) in the furnace to obtain the modified LLZO-based solid electrolyte membrane. Its SEM image is shown below. Figure 1 .

[0071] Example 2

[0072] The difference between this embodiment and Embodiment 1 is as follows:

[0073] The modified LLZO-based solid electrolyte membrane of this embodiment is composed of the following raw materials by weight: 4 parts modified LLZO powder, 0.2 parts calcined diatomaceous earth, 10.3 parts prepolymer, 0.3 parts photoinitiator, 1 part reactive diluent and 50 parts solvent;

[0074] In this embodiment, the mass ratio of LLZO powder: tartaric acid: phosphoric acid in the raw materials of the modified LLZO powder is 100:100:25.

[0075] Other raw materials, steps, and parameters are the same as in Example 1. The modified LLZO-based solid electrolyte membrane in this example has the following SEM image: Figure 2 .

[0076] Example 3

[0077] The difference between this embodiment and Embodiment 1 is as follows:

[0078] The modified LLZO-based solid electrolyte membrane of this embodiment is composed of the following raw materials by weight: 10 parts modified LLZO powder, 1.5 parts calcined diatomaceous earth, 10.3 parts prepolymer, 0.3 parts photoinitiator, 1 part reactive diluent and 30 parts solvent;

[0079] In this embodiment, the mass ratio of LLZO powder: tartaric acid: phosphoric acid in the raw materials of the modified LLZO powder is 100:150:50.

[0080] The other raw materials, steps and parameters are the same as in Example 1.

[0081] Example 4

[0082] The difference between this embodiment and Embodiment 1 is as follows:

[0083] In this embodiment, the mass ratio of LLZO powder: tartaric acid: phosphoric acid in the raw materials of the modified LLZO powder is 100:150:50.

[0084] The other raw materials, steps and parameters are the same as in Example 1.

[0085] Example 5

[0086] The difference between this embodiment and Embodiment 1 is as follows:

[0087] The prepolymer in this embodiment consists of 5 parts PUA, 2.5 parts IBOA, and 2.0 parts TPO;

[0088] Other raw materials, steps, and parameters are the same as in Example 1. The modified LLZO-based solid electrolyte membrane in this example has the following SEM image: Figure 3 .

[0089] Example 6

[0090] The difference between this embodiment and Embodiment 1 is as follows:

[0091] In S2, the mixing order is as follows: calcined diatomaceous earth and modified LLZO powder are stirred at 300 rpm for 1 hour, then prepolymer and photoinitiator are added and stirred at 300 rpm for 3 hours, and finally reactive diluent is added and mixed to obtain slurry.

[0092] The other raw materials, steps and parameters are the same as in Example 1.

[0093] Example 7

[0094] The difference between this embodiment and Embodiment 1 is as follows:

[0095] The film thickness of the cast film is 40~50μm;

[0096] The film was not dried after casting and was directly cured under ultraviolet light for 5 minutes.

[0097] The other raw materials, steps and parameters are the same as in Example 1.

[0098] Example 8

[0099] The difference between this embodiment and Embodiment 1 is as follows:

[0100] In S3 of this embodiment, sintering is carried out at 500°C for 4 hours, followed by 1000°C for 6 hours, and then cooled to room temperature with the furnace after sintering.

[0101] The other raw materials, steps and parameters are the same as in Example 1.

[0102] Example 9

[0103] The difference between this embodiment and Embodiment 1 is as follows:

[0104] In S3 of this embodiment, sintering is carried out at 200°C for 2 hours, followed by holding at 1000°C for 6 hours, and then cooling to room temperature with the furnace after sintering.

[0105] The other raw materials, steps and parameters are the same as in Example 1.

[0106] Example 10

[0107] The difference between this embodiment and Embodiment 1 is as follows:

[0108] In S3 of this embodiment, sintering is carried out at 200°C for 2 hours, followed by 500°C for 4 hours, and then cooled to room temperature with the furnace after sintering.

[0109] The other raw materials, steps and parameters are the same as in Example 1.

[0110] Comparative Example 1

[0111] The difference between this comparative example and Example 1 is as follows:

[0112] This comparative example directly uses LLZO powder, which has not been modified with phosphoric acid and tartaric acid.

[0113] The other raw materials, steps and parameters are the same as in Example 1.

[0114] Comparative Example 2

[0115] The difference between this comparative example and Example 1 is as follows:

[0116] This comparative example uses diatomaceous earth, which is uncalcined;

[0117] Other raw materials, steps, and parameters are the same as in Example 1. The SEM image of the modified LLZO-based solid electrolyte membrane in this comparative example is shown below. Figure 4 .

[0118] Comparative Example 3

[0119] The difference between this comparative example and Example 1 is as follows:

[0120] The prepolymers in this comparative example contain only cross-linked matrix resins and do not contain reactive diluent monomers or thermoplastic polymers.

[0121] The other raw materials, steps and parameters are the same as in Example 1.

[0122] Test case

[0123] The modified LLZO-based solid electrolyte membranes prepared in the above embodiments and comparative examples were used to prepare batteries, as follows:

[0124] (1) LiNi 0.9 Co 0.05 Mn 0.05 O2: Li 2.5 Yb 0.5 Zr 0.5 Cl6:Li6PS5Cl:VGCF (carbon nanofiber):PTFE (polytetrafluoroethylene) = 70:14:14:1:1 mass ratio, mixed and stirred evenly, then rolled into a composite positive electrode sheet;

[0125] (2) According to graphite: Li 2.5 Yb 0.5 Zr 0.5 The following materials were mixed in a mass ratio of Cl6:Li6PS5Cl:VGCF:PTFE = 70:14:14:1:1, stirred evenly, and then rolled into a composite negative electrode sheet.

[0126] (3) Composite positive electrode, composite negative electrode and modified LLZO based solid electrolyte membrane were assembled into CR2032 button cell in an argon-protected glove box. Constant current charge and discharge mode was used to conduct charge and discharge tests at a current density of 0.1C and a voltage range of 1.9~3.65V. The results of the battery’s first effect and capacity retention rate after 100 cycles are shown in Table 1. The first effect refers to the ratio of the first discharge capacity to the first charge capacity; the capacity retention rate is the ratio of the discharge capacity after 100 cycles to the first discharge capacity.

[0127]

[0128] Based on the above test results and SEM characterization results, we can conclude that:

[0129] according to Figure 1 and Figure 4It can be seen that the modified LLZO-based solid electrolyte membrane of Example 1 has a uniform pore distribution on its surface; in contrast, the membrane of Comparative Example 2 has fewer pores and is more collapsed overall; the uncalcined diatomaceous earth has low mechanical strength and will also hinder the uniform dispersion of lithium salt, resulting in a decrease in ionic conductivity; at the same time, the few and uneven pores cannot provide channels for ion migration.

[0130] according to Figure 2 and Figure 3 As can be seen from the SEM magnification images of Examples 2 and 5, the modified LLZO-based solid electrolyte membranes of both examples also have good pore structures.

[0131] In Comparative Example 1, the unmodified LLZO particles agglomerate within the membrane, failing to form a continuous ion conduction network and resulting in low charge transfer efficiency. Simultaneously, the agglomerates lead to uneven stress within the membrane, making it prone to microcracks during charging and discharging, thus exacerbating capacity decay.

[0132] Comparative Example 3: The lack of active diluent monomers resulted in excessively high slurry viscosity. After casting, the film structure was dense but brittle, and it was prone to cracking due to volume changes during charge and discharge. Without the polar groups of TPO, the lithium salt dissociation efficiency was low, the ionic conductivity was extremely low, and charge transfer was severely hindered, ultimately leading to a significant decline in first-efficiency and cycle performance.

[0133] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this invention. It should be understood that the above descriptions are merely specific embodiments of this invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A modified LLZO-based solid electrolyte membrane, characterized in that, The preparation materials include the following parts by weight: 4-15 parts modified LLZO powder, 0.4-2.4 parts calcined diatomaceous earth, 5-20 parts prepolymer, 0.1-2 parts photoinitiator, 0.5-5 parts reactive diluent and 25-60 parts solvent; The modifiers for the modified LLZO powder are tartaric acid and phosphoric acid; the modification steps for the modified LLZO powder are: dissolving tartaric acid in ethanol, then adding LLZO powder, and finally adding phosphoric acid. The prepolymer comprises a crosslinked matrix resin, an active diluent monomer, and a thermoplastic polymer; The crosslinking matrix resin is a polyurethane acrylate, an epoxy acrylate, or a polyester acrylate; the reactive diluent monomer is isobornyl acrylate, tert-butyl acrylate, or 2-methoxyethyl acrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate; the thermoplastic polymer is a thermoplastic polyolefin or polyethylene oxide. The reactive diluent is at least one of BYK111, BYK-348, BYK-410, Tego Rad 2300, and EFKA-3777.

2. The modified LLZO-based solid electrolyte membrane as described in claim 1, characterized in that, The mass ratio of the LLZO powder, tartaric acid, and phosphoric acid is 100:80~160:20~60.

3. The modified LLZO-based solid electrolyte membrane as described in claim 1, characterized in that, And / or, the mass ratio of the crosslinked matrix resin: the reactive diluent monomer: the thermoplastic polymer is 100:70~130:3~20.

4. The modified LLZO-based solid electrolyte membrane as described in claim 1, characterized in that, The composition of the LLZO powder is Li7La3Zr2O. 12 ; And / or, the D50 of the LLZO powder is 250~350nm.

5. The modified LLZO-based solid electrolyte membrane as described in claim 1, characterized in that, The solvent is at least one selected from ethanol, n-propanol, isopropanol, ethylene glycol monomethyl ether, ethyl acetate, and methyl isobutyl ketone. And / or, the photoinitiator is at least one of 1-HCPK, photoinitiator 2959, photoinitiator 819 and photoinitiator 907.

6. A method for preparing a modified LLZO-based solid electrolyte membrane, characterized in that, The method for preparing the modified LLZO-based solid electrolyte membrane as described in any one of claims 1 to 5 comprises the following steps: S1.LLZO powder was modified with a modifier to obtain modified LLZO powder; S2. The raw materials for preparing the modified LLZO-based solid electrolyte membrane are mixed according to the required proportions to obtain a slurry; S3. After the slurry is cast and molded, it is dried, cured, and then sintered to obtain a modified LLZO-based solid electrolyte membrane.

7. The method for preparing the modified LLZO-based solid electrolyte membrane as described in claim 6, characterized in that, In S1, the modification step is to dissolve tartaric acid in ethanol, then add LLZO powder, and finally add phosphoric acid. In S1, the modified material is washed with ethanol until neutral and then vacuum dried.

8. The method for preparing the modified LLZO-based solid electrolyte membrane as described in claim 6, characterized in that, In S2, the mixing sequence is as follows: calcined diatomaceous earth is dissolved in a solvent, then modified LLZO powder is added, followed by the prepolymer and photoinitiator, and finally the reactive diluent is added and mixed.

9. The method for preparing the modified LLZO-based solid electrolyte membrane as described in claim 6, characterized in that, In S3, the thickness of the film formed by casting is 15~35μm; And / or, in S3, the cast film is dried at 50~70℃ for 8~15min after casting; And / or, in S3, the casting process is carried out under an inert atmosphere. And / or, in S3, the drying method may be vacuum drying, hot air drying, or infrared heating drying; the drying temperature is 45~90℃; And / or, in S3, the curing method is ultraviolet curing.

10. The method for preparing the modified LLZO-based solid electrolyte membrane as described in claim 6, characterized in that, In S3, the sintering process is carried out at 150~300℃ for 1~4h, then at 400~600℃ for 2~8h, and finally at 800~1200℃ for 3~10h. And / or, the sintering is performed under a protective atmosphere; And / or, in S3, the heating rate during the sintering process is 2~5℃ / min, preferably 3~4℃ / min.

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