An inorganic-organic composite solid electrolyte lithium battery and its preparation method

Abstract

The present invention discloses an inorganic-organic composite solid electrolyte lithium battery and a preparation method thereof. The composite solid electrolyte is composed of polyethylene oxide, composite inorganic filler, lithium salt, and ionic liquid. The composite inorganic filler is ZIF-8 coated with SiO₂ (ZIF-8@SiO₂). The lithium salt is dissolved in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide to obtain a lithium ionic liquid. The ZIF-8@SiO₂ powder and the lithium ionic liquid are ground until uniform, and after vacuum drying, the ZIF-8@SiO₂ / IL filler is obtained. After the ZIF-8@SiO₂ / IL filler is mixed in a solvent, a polymer and a lithium salt are added, and after film formation, air drying, and drying, the composite solid electrolyte is obtained. The composite solid electrolyte of the present invention can provide a room temperature ionic and electronic conductivity of more than 10⁻⁴ S·cm⁻¹, a wide electrochemical window, and a high ion transference number. When it is applied to a solid lithium battery system, the battery has a high capacity and good cycle stability.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state lithium batteries, and more specifically, to an inorganic-organic composite solid electrolyte lithium battery and a preparation method thereof. Background Art

[0002] Given the increasing concerns about energy crises and climate change, the rise of global sustainable energy has stimulated the development of battery technologies, as batteries can maintain a viable and stable supply for individual users. In battery technologies, lithium-ion batteries still lead among various types of electrochemical energy storage technologies due to their high output power, low self-discharge, and environmental friendliness, and have been widely used in fields such as portable electronic devices, electric vehicles, and large-scale energy storage. For emerging electric vehicle technologies, lithium-ion batteries are currently the best power sources for long-time charging. However, currently commercially available lithium-ion batteries generally use liquid electrolytes, and their disadvantages such as insecurity, liquid leakage, uncontrollable side reactions, and dendrite problems severely limit their further development.

[0003] Solid-state batteries are batteries in which all components, including the electrolyte, are in a solid state, which can effectively solve these practical problems. In particular, solid electrolytes, as the key part of solid-state batteries, play a crucial role in addressing the challenges of traditional batteries. However, existing solid-state batteries have problems such as low ionic conductivity, narrow electrochemical window, low ion transference number, and poor interfacial compatibility, which greatly affect battery performance. For the problem of poor interfacial compatibility, it can be effectively improved by introducing polymer components into the raw materials for preparing solid electrolytes. And the low ionic conductivity can be improved by preparing composite solid electrolytes by adding suitable fillers to a solid polymer electrolyte matrix. Currently, the mainstream fillers are mostly nanoparticles, and these nano-fillers are randomly distributed in the polymer matrix and cannot provide a continuous lithium-ion transport path. In addition, when the addition amount of nano-fillers exceeds a certain degree, agglomeration will occur. This greatly limits the improvement of ionic conductivity.

[0004] Publication No. CN 114243088 A provides a PEO-based composite solid electrolyte and a preparation method thereof. The invention uses a solution mixing method to uniformly distribute MOFs particles and lithium salts in PEO, and an ionic liquid is added as a plasticizer to form a multi-ion channel network. However, since anions and cations can move freely, the prepared solid electrolyte has a low lithium-ion transference number (0.48), and as the addition amount of the ionic liquid increases, it becomes difficult for the solid electrolyte to form a film. Therefore, its improvement of the room-temperature ionic conductivity of the solid electrolyte is also relatively limited (4.9×10 -5 S·cm -1 ).

[0005] Therefore, developing a solid electrolyte with high room-temperature ionic conductivity, wide electrochemical window, and high ion transference number is an urgent problem to be solved in this field. Summary of the Invention

[0006] On the one hand, the object of the present invention is to provide a preparation method of a solid electrolyte material based on a MOFs composite material. By capillary adsorption, ionic liquids are confined in the pores of the MOFs material to achieve selective transport of lithium ions, thereby obtaining a high lithium ion transference number. Due to the limited pore structure of common MOFs materials, the ionic liquids that can be adsorbed are relatively limited, making the improvement of ionic conductivity not obvious enough. Therefore, mesoporous SiO2 is introduced on the surface of the MOFs material to obtain high ionic conductivity by adsorbing more ionic liquids.

[0007] The technical solution of the present invention is to combine SiO2 with metal-organic frameworks to form a new composite inorganic filler for use in solid electrolytes. By a solution-based chemical process to improve the mechanical properties of the MOFs material, a harder mesoporous SiO2 shell is deposited on the ZIF-8 material (ZIF-8@SiO2). Since SiO2 has a larger pore size than ZIF-8, IL can easily penetrate this shell layer and reach the core phase (ZIF-8@SiO2 / IL) without destroying the intrinsic properties of ZIF-8. Taking ZIF-8@SiO2 / IL as a composite filler and adding it to a PEO-based solid electrolyte, a novel inorganic-organic composite solid electrolyte is obtained. The prepared inorganic-organic composite solid electrolyte has an ionic conductivity exceeding 10 -4 S·cm -1 .

[0008] A preparation method of an inorganic-organic composite solid electrolyte, comprising the following steps:

[0009] S1. Preparation of ZIF-8: Dissolve a zinc salt in solvent 1 to obtain solution A; dissolve 2-methylimidazole in solvent 1 to obtain solution B; quickly pour the ultrasonically treated solution B into solution A, stir at room temperature, wash the white precipitate with a solvent, centrifuge, and vacuum dry to obtain ZIF-8;

[0010] Further, the zinc salt is one of zinc nitrate hexahydrate or zinc acetate dihydrate, preferably zinc nitrate hexahydrate;

[0011] Further, the solvent 1 is at least one of methanol and water, preferably methanol;

[0012] Further, the mass ratio of the zinc salt to 2-methylimidazole is 1:1 to 2.5;

[0013] Further, the ultrasonic treatment time is 5 to 30 min;

[0014] Further, the stirring time is 18 to 30 h.

[0015] S2. Preparation of ZIF-8@SiO2: Disperse the ZIF-8 powder in Solvent 2 and perform ultrasonic treatment. Then, add an aqueous solution of 15 to 30 wt% cetyltrimethylammonium chloride (CTAC) and stir for 10 to 40 min. Next, dropwise add tetraethyl orthosilicate (TEOS) and stir for 0.5 to 2 h. Then, wash with Solvent 2, centrifuge, and dry to obtain the composite nanofiller ZIF-8@SiO2;

[0016] Further, Solvent 2 is one of methanol or ethanol, preferably methanol;

[0017] Further, the mass concentration of the ZIF-8 solution is 4 to 12 mg / mL;

[0018] Further, the volume ratio of the ZIF-8 solution to the aqueous solution of cetyltrimethylammonium chloride (CTAC) is 1:0.8 to 1.2;

[0019] Further, the volume ratio of the ZIF-8 solution to tetraethyl orthosilicate (TEOS) is 1:0.6 to 1.2.

[0020] Further, the dropping rate of tetraethyl orthosilicate (TEOS) is 50 - 200 μL / min.

[0021] S3. Preparation of ZIF8@SiO2 / IL: Dissolve the lithium salt in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide to obtain a lithium ionic liquid. Add the ZIF-8@SiO2 powder to the lithium ionic liquid, grind and mix evenly, and then perform vacuum drying to obtain ZIF-8@SiO2 / IL;

[0022] Further, the lithium salt is one of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium perchlorate, and lithium trifluoromethanesulfonate, preferably lithium bis(trifluoromethanesulfonyl)imide;

[0023] Further, the mass ratio of ZIF-8@SiO2 to the lithium ionic liquid is 1:0.8 to 1.2;

[0024] Further, the temperature of the vacuum drying is 100 to 140 °C;

[0025] Further, the time of the vacuum drying is 12 to 18 h.

[0026] S4. Preparation of inorganic-organic composite solid electrolyte: In a glove box, the polymer and the lithium salt are uniformly mixed in Solvent 3, the ZIF-8@SiO2 / IL filler is added and stirred magnetically. After stirring evenly, it is cast on a polytetrafluoroethylene mold, left to stand and dry in air, and then dried in vacuum to obtain the inorganic-organic composite solid electrolyte;

[0027] Further, the polymer is one of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), poly(vinylidene fluoride - hexafluoropropylene) (PVDF-HFP), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), and preferably polyethylene oxide (PEO);

[0028] Further, Solvent 3 is one of anhydrous acetonitrile, N,N-dimethylformamide, N-methylpyrrolidone, and preferably anhydrous acetonitrile;

[0029] Further, the mass ratio of the polyethylene oxide (PEO) to the lithium salt is 12 - 20:1;

[0030] Further, the addition amount of the ZIF-8@SiO2 / IL filler is 5 - 40 wt% of the total mass of the polyethylene oxide (PEO) and the lithium salt;

[0031] Further, the time of the magnetic stirring is 18 - 36 h;

[0032] Further, the time of standing and drying in air is 12 - 24 h;

[0033] Further, the condition of the glove box is an argon atmosphere, and the concentrations of water and oxygen are controlled below 0.01 ppm;

[0034] Further, the drying temperature in the vacuum drying oven is 45 - 55 °C, and the time is 12 - 36 h.

[0035] Further, the inorganic-organic composite solid electrolyte is obtained by the preparation method according to any one of claims 1 - 5.

[0036] Further, the thickness of the inorganic-organic composite solid electrolyte is 5 - 200 μm.

[0037] On the other hand, the present invention provides a solid-state lithium battery, which contains a positive electrode material, a negative electrode material, and the above-mentioned inorganic-organic composite solid electrolyte material.

[0038] The positive electrode material is selected from one of lithium iron phosphate (LiFePO4), lithium manganese oxide (LiMn2O4), and nickel cobalt manganese (NCM) ternary materials, and preferably lithium iron phosphate (LiFePO4).

[0039] The negative electrode material selected is metallic lithium.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] (1) For the inorganic-organic composite solid electrolyte based on ZIF-8@SiO2-based ion conductor provided by the present invention, the polymer component can improve the contact between the electrolyte and the electrode. The introduction of the ZIF-8@SiO2-based ion conductor provides a fast lithium ion transport channel, thereby exhibiting excellent electrochemical performance, with an ionic conductivity of 2.35×10 -4 S·cm -1 at room temperature, a lithium ion transference number of 0.6 and a wide electrochemical window of more than 5.5V.

[0042] (2) When the inorganic-organic composite solid electrolyte based on ZIF-8@SiO2-based ion conductor provided by the present invention is applied to a solid-state lithium battery, there is good interfacial compatibility between the electrode material and the electrolyte, which improves the diffusion rate of lithium ions and exhibits excellent cycling performance and rate performance.

[0043] (3) The preparation method provided by the present invention has a simple process, is green and environmentally friendly, and is easy to scale up production. The prepared inorganic-organic solid electrolyte based on ZIF-8@SiO2-based ion conductor has advantages such as consistent morphology and controllable thickness. Description of the Drawings

[0044] Figure 1 is the XRD pattern of ZIF-8@SiO2 of the present invention;

[0045] Figure 2 is the TEM image of ZIF-8@SiO2 of the present invention;

[0046] Figure 3 The left figure in is the nitrogen adsorption / desorption curve of ZIF-8@SiO2, and the right figure is the pore size distribution diagram of ZIF-8@SiO2;

[0047] Figure 4 is the SEM image of the inorganic-organic composite solid electrolyte PZS15 in Example 1 of the present invention;

[0048] Figure 5 is the ionic conductivity diagram of the inorganic-organic composite solid electrolyte PZS15 in Example 1 of the present invention at different temperatures;

[0049] Figure 6 is the LSV test diagram of the inorganic-organic composite solid electrolyte PZS15 in Example 1 of the present invention;

[0050] Figure 7It is the graph of the lithium ion transference number of the inorganic-organic composite solid electrolyte PZS15 in Example 1 of the present invention; among them, the left graph is the current-time graph of DC polarization, and the right graph is the impedance graph before and after polarization;

[0051] Figure 8 It is the graph of the interface stability test of the lithium symmetric battery Li||PZS15||Li assembled with the inorganic-organic composite solid electrolyte PZS15 in Example 1 of the present invention;

[0052] Figure 9 It is the first charge-discharge curve of the solid-state lithium battery LiFePO4||PZS15||Li assembled with the inorganic-organic composite solid electrolyte PZS15 in Example 1 of the present invention at a rate of 0.2C;

[0053] Figure 10 It is the cycle performance graph of the solid-state lithium battery LiFePO4||PZS15||Li assembled with the inorganic-organic composite solid electrolyte PZS15 in Example 1 of the present invention at a rate of 0.2C;

[0054] Figure 11 It is the rate performance graph of the solid-state lithium battery LiFePO4||PZS15||Li assembled with the inorganic-organic composite solid electrolyte PZS15 in Example 1 of the present invention. Detailed implementation manners

[0055] The present invention will be further described in detail below through specific implementation cases and accompanying drawings. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the protection scope of the present invention. After reading the present invention, various equivalent modifications made by those skilled in the art fall within the scope defined by the appended claims of this application.

[0056] Unless otherwise specified, all raw materials and reagents of the present invention are raw materials and reagents on the conventional market.

[0057] Example 1

[0058] Preparation of the inorganic-organic composite solid electrolyte PZS15:

[0059] 1. Preparation of ZIF-8 nanoparticles

[0060] Dissolve 0.89 g of zinc nitrate hexahydrate in 30 mL of methanol solution to obtain solution A; dissolve 1.97 g of 2-methylimidazole in 20 mL of methanol solution to obtain solution B; quickly pour solution B after 20 min of ultrasonic treatment into solution A, mix the two, stir at room temperature for 24 h, centrifuge at 9000 rpm for 10 min to obtain a white precipitate, wash the white precipitate with methanol, repeat the washing and centrifugation three times, and then vacuum dry at 60 °C for 24 h.

[0061] 2. Preparation of ZIF-8@SiO2

[0062] 50 mg of ZIF-8 was dispersed in 5 mL and sonicated for 5 min, and then mixed with a solution containing 0.25 g of 2-methylimidazole, 33 mL of water and 21 mL of methanol, and sonicated for 5 min; 0.55 mL (25 wt%) of an aqueous solution of dodecyltrimethylammonium chloride (CTAC) was added and stirred for 20 min, and then 0.4 mL of tetraethyl orthosilicate (TEOS) was added dropwise to the above solution within 3 min and stirred for 1 h. The precipitate was washed with anhydrous methanol and centrifuged three times, and dried in vacuo at 60 °C for 12 h; annealed at 250 °C for 7 h in an argon atmosphere to remove dodecyltrimethylammonium chloride (CTAC); the annealed ZIF-8@SiO2 was placed in a glove box for the next experiment. (H2O, O2 < 0.01 ppm). -1 Heated to 250 °C at a rate of 2 °C min

[0063] 3. Preparation of ZIF-8@SiO2 / IL

[0064] LiTFSI was dissolved in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide to obtain an ionic liquid (IL) containing Li + with a concentration of 1 mol / L. The ZIF-8@SiO2 powder was added to an appropriate amount of the lithium ionic liquid, ground and mixed evenly, and ZIF-8@SiO2 / IL was obtained after drying in vacuo. ZIF-8@SiO2 / IL was stored in a glove box.

[0065] 4. Preparation of PEO-based composite solid electrolyte PZS15

[0066] PEO with a molecular weight of 600000 was vacuum-dried at 60 °C for 24 h, and then transferred into a glove box. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was vacuum-dried at 100 °C for 24 h and then transferred into the glove box. The water and oxygen concentrations in the glove box were controlled below 0.01 ppm. 0.112 g of ZIF-8@SiO2 / IL was added to 8 mL of anhydrous acetonitrile. After being evenly dispersed, 0.55 g of PEO and 0.199 g of LiTFSI were added according to a molar ratio of 18:1. After stirring until fully dissolved, it was stirred for 24 h. After the PEO was completely dissolved, the PEO mixture was poured into a polytetrafluoroethylene mold, left standing in the glove box for 12 h to air-dry naturally, and then transferred to a vacuum drying oven and vacuum-dried at 50 °C for 24 h to completely remove the residual acetonitrile solvent. The dried composite solid electrolyte membrane was punched into circular pieces with a diameter of 16 mm and placed in the glove box for standby, that is, the inorganic-organic composite solid electrolyte PZS15 with the addition amount of ZIF-8@SiO2 / IL being 15% of the total mass of PEO and LiTFSI was obtained. Through physical characterization and electrochemical tests, PZS15 has a smooth and flat surface, the MOFs are evenly dispersed, and there is no obvious agglomeration phenomenon. The conductivity at room temperature is 2.35×10 -4 S·cm -1 , the lithium ion transference number is 0.6, and the electrochemical window exceeds 5.5 V.

[0067] Example 2

[0068] Preparation of inorganic-organic composite solid electrolyte PZS5:

[0069] Example 2 provides a preparation method of a composite solid electrolyte membrane based on ZIF-8@SiO2-based ion conductor. Compared with Example 1, the difference is that the mass fraction of the filler in the composite solid electrolyte membrane is changed. In Example 2, the mass fraction of the filler is 5%, and the remaining steps are the same as those in Example 1, which will not be elaborated here.

[0070] Example 3

[0071] Preparation of inorganic-organic composite solid electrolyte PZS10:

[0072] Example 3 provides a preparation method of a composite solid electrolyte membrane based on ZIF-8@SiO2-based ion conductor. Compared with Example 1, the difference is that the mass fraction of the filler in the composite solid electrolyte membrane is changed. In Example 3, the mass fraction of the filler is 10%, and the remaining steps are the same as those in Example 1, which will not be elaborated here.

[0073] Example 4

[0074] Preparation of inorganic-organic composite solid electrolyte PZS20:

[0075] Example 4 provides a method for preparing a composite solid electrolyte membrane based on a ZIF-8@SiO2-based ionic conductor. Compared with Example 1, the difference lies in changing the mass fraction of the filler in the composite solid electrolyte membrane. In Example 4, the mass fraction of the filler is 20%, and the remaining steps are the same as those in Example 1, which will not be elaborated here.

[0076] Apply the composite electrolyte prepared in Example 1 to a solid-state lithium battery and conduct electrical tests.

[0077] Preparation of the positive electrode: Weigh LiFePO4, acetylene black, and PEO in a mass ratio of 8:1:1. After mixing LiFePO4 and acetylene black evenly in a mortar, add PEO, then drop an appropriate amount of N-methylpyrrolidone. After mixing evenly, coat the slurry on an aluminum foil. After vacuum drying at 80°C for 24 h, punch it into a circular piece with a diameter of 12 mm as the positive electrode material of the solid-state lithium battery and place it in a glove box for standby.

[0078] Assembly of the battery: The negative electrode of the solid-state lithium battery is selected as a lithium metal sheet. Assemble a 2032 solid-state lithium battery in the glove box in the order of positive electrode case - positive electrode material - composite solid electrolyte - negative electrode material - gasket - shrapnel - negative electrode case.

[0079] As Figure 8 shown, the lithium symmetric battery assembled with the inorganic-organic composite solid electrolyte PZS15 can stably cycle for more than 1000 h in the continuous lithium plating / stripping experiment at a current density of 0.2 mA cm -2 . This indicates that metallic lithium can be stably deposited and precipitated on PZS15, and also indicates that this inorganic-organic composite solid electrolyte has good ability to inhibit the growth of lithium dendrites.

[0080] Figure 9 is the first charge-discharge curve of the solid-state lithium battery LiFePO4||PZS15||Li at a 0.2C rate. Its first discharge specific capacity reaches 155.6 mA h g -1 . Figure 10 is the cycle performance graph of the solid-state lithium battery LiFePO4||PZS15||Li at a 0.2C rate. The discharge capacity after 100 cycles is 150.1 mA h g -1 , retaining 96.5% of the initial discharge capacity. Figure 11 is the rate performance graph of the solid-state lithium battery LiFePO4||PZS15||Li at different charge-discharge rates. As can be seen from the figure, it has good rate performance.

[0081] Comparative Example 1

[0082] Measure 8 mL of anhydrous acetonitrile, add 0.55 g of PEO and 0.199 g of LiTFSI, stir until fully dissolved, and then stir for 24 h. After the PEO is completely dissolved, pour the PEO mixture into a polytetrafluoroethylene mold, let it stand in the glove box for 12 h to dry naturally, and then transfer it to a vacuum drying oven for vacuum drying at 50 °C for 24 h to completely remove the residual acetonitrile solvent. Punch the dried composite solid electrolyte membrane into 16 mm diameter discs and place them in the glove box for standby. Measure its electrochemical impedance spectroscopy at room temperature, and the ionic conductivity is 5.62×10 -7 S·cm -1 。

[0083] Comparative Example 2

[0084] Add 0.112 g of ZIF8@SiO2 to 8 mL of anhydrous acetonitrile, disperse it evenly, and then add 0.55 g of PEO and 0.199 g of LiTFSI according to a molar ratio of 18:1. Stir until fully dissolved, and then stir for 24 h. After the PEO is completely dissolved, pour the PEO mixture into a polytetrafluoroethylene mold, let it stand in the glove box for 12 h to dry naturally, and then transfer it to a vacuum drying oven for vacuum drying at 50 °C for 24 h to completely remove the residual acetonitrile solvent. Punch the dried composite solid electrolyte membrane into 16 mm diameter discs and place them in the glove box for standby. Measure its electrochemical impedance spectroscopy at room temperature, and the ionic conductivity is 2.02×10 -5 S·cm -1 。

[0085] In summary, the preparation method provided by the present invention effectively synthesizes an inorganic-organic composite solid electrolyte based on ZIF-8@SiO2-based ionic conductors, which has high ionic conductivity, a wide electrochemical window, and good compatibility with lithium metal. The assembled solid-state lithium battery LiFePO4||PZS15||Li has a high specific capacity and good cycling performance. The present invention creatively combines SiO2 with a metal-organic framework, encapsulates ZIF-8 with a small pore diameter inside SiO2 with a large pore diameter as a composite inorganic filler and applies it to a solid electrolyte. Moreover, the whole process has a simple process, a short flow, is easy to operate, and is suitable for large-scale industrial production.

[0086] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A preparation method of an inorganic-organic composite solid electrolyte, characterized in that, It includes the following steps: S1. Preparation of ZIF-8: Dissolve a zinc salt in Solvent 1 to obtain Solution A; dissolve 2-methylimidazole in Solvent 1 to obtain Solution B; quickly pour the ultrasonically treated Solution B into Solution A, stir at room temperature, then wash the white precipitate with a solvent, centrifuge, and vacuum dry to obtain ZIF-8; S2. Preparation of ZIF-8@SiO2: Disperse the ZIF-8 powder in Solvent 2 and perform ultrasonic treatment, add a 15 - 30 wt% aqueous solution of dodecyltrimethylammonium chloride and stir for 10 - 40 min, then dropwise add tetraethyl orthosilicate and stir for 0.5 - 2 h, and then wash, centrifuge, and dry with Solvent 2 to obtain the composite nano-filler ZIF-8@SiO2; S3. Preparation of ZIF-8@SiO2 / IL: Dissolve a lithium salt in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide to obtain a lithium ionic liquid, add the ZIF-8@SiO2 powder to the lithium ionic liquid, grind and mix evenly, and vacuum dry to obtain ZIF-8@SiO2 / IL; S4. Preparation of inorganic-organic composite solid electrolyte: In a glove box, mix polyethylene oxide and the lithium salt evenly in Solvent 3, add the ZIF-8@SiO2 / IL filler and stir magnetically. After stirring evenly, cast it on a polytetrafluoroethylene mold, let it stand to dry, and vacuum dry to obtain the inorganic-organic composite solid electrolyte.

2. The preparation method of the inorganic-organic composite solid electrolyte according to claim 1, characterized in that, In step S1: The Solvent 1 is at least one of methanol and water; The zinc salt is one of zinc nitrate hexahydrate or zinc acetate dihydrate; The mass ratio of the zinc salt to 2-methylimidazole is 1:0.8 - 1.6; The ultrasonic treatment time is 5 - 30 min; The stirring time is 18 - 30 h.

3. The preparation method of the inorganic-organic composite solid electrolyte according to claim 1, characterized in that, In step S2: The Solvent 2 is one of methanol or ethanol; The mass concentration of the ZIF-8 solution is 4 - 12 mg / mL; The volume ratio of the ZIF-8 solution to the aqueous solution of dodecyltrimethylammonium chloride is 1:0.8 - 1.2; The volume ratio of the ZIF-8 solution to tetraethyl orthosilicate is 1:0.6 - 1.2; The dropping rate of tetraethyl orthosilicate is 50 - 200 μL / min.

4. The preparation method of the inorganic-organic composite solid electrolyte according to claim 1, wherein In step S3: The lithium salt is one of lithium bis(trifluoromethylsulfonyl)imide, lithium hexafluorophosphate, lithium perchlorate, and lithium trifluoromethanesulfonate; The mass ratio of ZIF-8@SiO2 to the lithium ionic liquid is 1:0.8 - 1.2; The vacuum drying temperature is 100 - 140 °C; The vacuum drying time is 12 - 18 h.

5. The preparation method of the inorganic-organic composite solid electrolyte according to claim 1, wherein In step S4: The Solvent 3 is one of anhydrous acetonitrile, N,N-dimethylformamide, and N-methylpyrrolidone; The molar ratio of polyethylene oxide to the lithium salt is 12 - 20:1; The addition amount of the ZIF-8@SiO2 / IL filler is 5 - 40 wt% of the total mass of polyethylene oxide and the lithium salt; The magnetic stirring time is 18 - 36 h; The time for standing and drying in the glove box is 12 - 24 h; The conditions of the glove box are an argon atmosphere, and the water and oxygen concentrations are controlled below 0.01 ppm; The vacuum drying temperature is 45 to 55 °C; The vacuum drying time is 12 to 36 h.

6. An inorganic-organic composite solid electrolyte, characterized in that: Obtained by the preparation method according to any one of claims 1 to 5.

7. The inorganic-organic composite solid electrolyte according to claim 6, wherein The thickness of the polyethylene oxide-based inorganic-organic composite solid electrolyte is 5 to 200 μm.

8. An inorganic-organic composite solid electrolyte lithium battery, characterized in that, The solid-state lithium battery includes a positive electrode, a negative electrode, and the inorganic-organic composite solid electrolyte according to any one of claims 6 or 7.

9. The inorganic-organic composite solid electrolyte lithium battery according to claim 8, characterized in that: The positive electrode is one of lithium iron phosphate, lithium manganate, and nickel cobalt manganese ternary material; The negative electrode is metallic lithium.

10. An application of the inorganic-organic composite solid electrolyte according to claim 6 or 7 in the field of lithium batteries.

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