Inorganic-organic composite solid electrolyte and preparation method and application thereof

Abstract

The invention discloses an inorganic-organic composite solid electrolyte as well as a preparation method and application thereof, and relates to the technical field of electrolytes. The inorganic-organic composite solid electrolyte comprises a polymer matrix, a filler and a lithium salt, wherein the polymer matrix is lithium perfluorosulfonate, the filler is lithium lanthanum zirconium oxide, and the lithium salt is LiTFSI. The inorganic-organic composite solid electrolyte is high in ionic conductivity, good in stability and capable of inhibiting growth of lithium dendrites, an electrochemical window can reach 4.6 V or above, and the inorganic-organic composite solid electrolyte can adapt to most of electrode materials in the market and is suitable for preparing batteries, especially lithium batteries. The obtained battery has excellent electrochemical stability, lithium stability, cycling stability, ion migration performance and rate capability, and can be applied to the field of new energy automobiles.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytes, and in particular to an inorganic-organic composite solid electrolyte and a preparation method and application thereof. Background Art

[0002] The surge in the content of greenhouse gases such as carbon dioxide has brought about many problems such as global warming. Developing new energy vehicles to replace traditional fuel vehicles is an effective way to reduce the emission of greenhouse gases such as carbon dioxide. However, due to the limitations of power batteries, new energy vehicles still have problems in terms of driving range, charging efficiency, safety performance, etc. Therefore, the development of batteries with high capacity and high energy density is a key step in the promotion of new energy vehicles. Among energy storage devices, lithium batteries have a high theoretical specific capacity (3860mAh / g 1 ), low mass density (0.534g / cm 3 ), low electrode potential (-3.04V relative to standard hydrogen electrode), high power density and high energy density, making it one of the most promising energy storage devices.

[0003] However, most lithium batteries currently use liquid electrolytes, which makes them face many difficulties in practical application scenarios, such as: 1) Organic liquid electrolytes are mainly organic molecules in the electrolyte, which are easy to burn. If the heat released during the battery charging and discharging process cannot be dissipated in time, it is likely to cause combustion or even explosion, resulting in safety problems; 2) Liquid electrolytes cannot effectively inhibit the growth of dendrites. During the long cycle of the battery, dendrites can easily pierce the diaphragm, causing direct contact between the positive and negative electrodes, resulting in short circuit failure of the battery; 3) In order to meet the requirements of high voltage, high power and high energy density of the battery, liquid electrolytes usually need to be added with various additives, resulting in high electrolyte prices and increased battery manufacturing costs. Using solid electrolytes to replace liquid electrolytes and diaphragms in the battery assembly process can not only save costs, but also reduce the use of liquid organic matter and reduce the risk of flammability and explosion. At the same time, solid electrolytes have higher mechanical strength than diaphragms, which is conducive to promoting the cycle stability and safety performance of the battery.

[0004] At present, the solid electrolytes on the market are mainly divided into inorganic solid electrolytes, polymer solid electrolytes and composite solid electrolytes. Among them, inorganic solid electrolytes have high ionic conductivity and excellent mechanical strength, but the direct contact with the electrode is poor, resulting in significant interface resistance, which is not conducive to battery performance; polymer solid electrolytes are soft, easy to handle, easy to prepare on a large scale, and more suitable for actual factory production, but the room temperature ionic conductivity is relatively low, and it cannot effectively inhibit the growth of dendrites; and the preparation process of existing composite solid electrolytes is relatively complicated, which is not conducive to actual industrial application. . Summary of the invention

[0005] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the purpose of the present invention is to provide an inorganic-organic composite solid electrolyte, which combines a specific polymer matrix with a specific proportion of fillers to improve the ionic conductivity of the inorganic-organic composite solid electrolyte and effectively inhibit the growth of lithium dendrites.

[0006] The second aspect of the present invention is to provide a method for preparing an inorganic-organic composite solid electrolyte.

[0007] A third aspect of the present invention is to provide a battery.

[0008] The fourth aspect of the present invention is to provide an application of an inorganic-organic composite solid electrolyte or battery.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] The first aspect of the present invention provides an inorganic-organic composite solid electrolyte, comprising a polymer matrix, a filler and a lithium salt; the polymer matrix is ​​lithium perfluorosulfonate, the filler is lithium lanthanum zirconium oxide, and the lithium salt is LiTFSI.

[0011] The present invention uses perfluorosulfonic acid lithium (PFSA-Li) as a polymer matrix, introduces lithium lanthanum zirconium oxide (LLZTO), and uses a specific lithium salt LiTFSI at the same time. The obtained inorganic-organic composite solid electrolyte has excellent ionic conductivity and mechanical strength, can effectively inhibit the growth of lithium dendrites, and has excellent electrochemical stability. At the same time, the main chain of PFSA-Li is composed of carbon-fluorine bonds, and the electronegativity of fluorine atoms is strong, so that the carbon-fluorine bonds have high bond energy, giving PFSA-Li excellent chemical stability and thermal stability, which helps the inorganic-organic composite solid electrolyte to maintain stable performance under harsh conditions such as strong acids, strong bases and high temperatures (maximum temperature 200°C). The battery assembled using the inorganic-organic composite solid electrolyte has excellent cycle stability and rate performance.

[0012] In addition, the present invention uses PFSA-Li as a matrix and LLZTO as a filler. PFSA-Li itself has good LiTFSI dissolution and dissociation capabilities, and LLZTO can provide more ion transmission pathways, thereby significantly improving the ion conductivity of the inorganic-organic composite solid electrolyte. Therefore, the inorganic-organic composite solid electrolyte of the present invention can achieve high ion conductivity without adding molecular coordination regulators such as DFBOP.

[0013] In some embodiments of the present invention, the inorganic-organic composite solid electrolyte does not contain a molecular coordination regulator.

[0014] In some embodiments of the present invention, the mass of the filler is 5-15% of the mass of the polymer matrix.

[0015] In some embodiments of the present invention, the mass of the filler is 5-11% of the mass of the polymer matrix.

[0016] In some specific embodiments of the present invention, the mass of the filler is 9-11% of the mass of the polymer matrix.

[0017] In some embodiments of the present invention, the mass of the lithium salt is 20-120% of the mass of the polymer matrix.

[0018] In some embodiments of the present invention, the mass of the lithium salt is 40-80% of the mass of the polymer matrix.

[0019] In some specific embodiments of the present invention, the mass of the lithium salt is 50-70% of the mass of the polymer matrix.

[0020] In some examples of the present invention, the mass of the lithium salt is 55-65% of the mass of the polymer matrix.

[0021] In some embodiments of the present invention, the mass ratio of the polymer matrix, filler and lithium salt is (1-50):1:(1-50); preferably (1-25):1:(1-25); further preferably (5-15):1:(4-8); more preferably (9-11):1:(5-7).

[0022] In some embodiments of the present invention, the particle size of the lithium lanthanum zirconium oxide is 2 to 6 μm.

[0023] In some embodiments of the present invention, the particle size of the lithium lanthanum zirconium oxide is 3-5 μm.

[0024] As a filler, the particle size of LLZTO is related to the specific surface area, which in turn affects the ion transport pathway. The present invention selects LLZTO particles of 2 to 6 μm to meet the demand for high ion conductivity, and micron-sized LLZTO has higher mechanical strength than nano-sized LLZTO particles, which is more conducive to inhibiting the growth of lithium dendrites, and is also conducive to improving the electrochemical window and adapting to more electrode materials.

[0025] In some embodiments of the present invention, the method for preparing lithium lanthanum zirconium oxide comprises the following steps:

[0026] Lithium hydroxide, lanthanum oxide, zirconium oxide and tantalum pentoxide are mixed and dissolved in a solvent, and part of lithium hydroxide is additionally added. After mixing, the mixture is dried and calcined to obtain the lithium lanthanum zirconium oxide.

[0027] In some embodiments of the present invention, the stoichiometric ratio of lithium hydroxide, lanthanum oxide, zirconium oxide and tantalum pentoxide is (6-7):(1-2):(1-2):(0.2-0.4).

[0028] In some embodiments of the present invention, the solvent is an alcohol solution, such as isopropanol.

[0029] In some embodiments of the present invention, the additional lithium hydroxide is added at 8-12% of the stoichiometric ratio of the lithium hydroxide first added.

[0030] In some embodiments of the present invention, the calcination condition is calcination at a temperature of 900-1000° C. for 10-14 hours.

[0031] In some embodiments of the present invention, the drying temperature is 60-80° C. to remove the solvent.

[0032] In some embodiments of the present invention, the molecular weight of the lithium perfluorosulfonate is 770-810 g / mol.

[0033] In some embodiments of the present invention, the inorganic-organic composite solid electrolyte is in the form of a thin film; the thickness of the inorganic-organic composite solid electrolyte is 1 to 50 μm.

[0034] In some embodiments of the present invention, the thickness of the inorganic-organic composite solid electrolyte is 1 to 25 μm.

[0035] In some specific embodiments of the present invention, the thickness of the inorganic-organic composite solid electrolyte is 10 to 25 μm.

[0036] Energy density is a key parameter in solid-state batteries. The electrolyte itself does not provide energy, so the electrolyte thickness should be as thin as possible, otherwise it is not conducive to improving the overall energy density of the battery. The inorganic-organic composite solid electrolyte of the present invention is thin and controllable, and has a higher advantage in improving energy density.

[0037] The second aspect of the present invention provides a method for preparing the inorganic-organic composite solid electrolyte according to the first aspect of the present invention, comprising the following steps:

[0038] The polymer matrix is ​​dissolved in an organic solvent, and fillers and lithium salts are added and mixed to obtain electrolyte slurry; the electrolyte slurry is dried to remove the solvent to obtain the inorganic-organic composite solid electrolyte.

[0039] The inorganic-organic composite solid electrolyte of the present invention can be prepared by simple mixing and drying, and the preparation method is simple and easy, and is suitable for large-scale production.

[0040] In some embodiments of the present invention, the solid content of the electrolyte slurry is 10 to 80 wt %.

[0041] In some embodiments of the present invention, the solid content of the electrolyte slurry is 10-50 wt %.

[0042] In some specific embodiments of the present invention, the solid content of the electrolyte slurry is 20-30 wt %.

[0043] In some embodiments of the present invention, the drying temperature is 50-200°C.

[0044] In some embodiments of the present invention, the drying temperature is 50-150°C.

[0045] In some specific embodiments of the present invention, the drying temperature is 50-70°C.

[0046] In some embodiments of the present invention, the drying time is 12 to 48 hours.

[0047] In some embodiments of the present invention, the drying time is 12 to 36 hours.

[0048] In some embodiments of the present invention, the drying method is: coating the electrolyte slurry on a glass plate and drying it. The thickness of the inorganic-organic composite solid electrolyte can be adjusted by controlling the coating thickness.

[0049] In some embodiments of the present invention, stirring is adopted during the dissolving and mixing processes; the stirring speed is 9000-11000 r / min.

[0050] In some embodiments of the present invention, the organic solvent includes at least one of N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO).

[0051] The third aspect of the present invention provides a battery, comprising the inorganic-organic composite solid electrolyte described in the first aspect of the present invention.

[0052] In some embodiments of the invention, the battery comprises a lithium battery.

[0053] In some embodiments of the present invention, the positive electrode material of the lithium battery is lithium iron phosphate.

[0054] The fourth aspect of the present invention provides an application of the inorganic-organic composite solid electrolyte described in the first aspect of the present invention or the battery described in the third aspect of the present invention in the field of new energy vehicles.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] (1) The inorganic-organic composite solid electrolyte of the present invention contains three components: PFSA-Li, LLZTO and LiTFSI. The perfluorinated main chain of PFSA-Li has high chemical stability and thermal stability. The lithium sulfonate group can provide an effective ion conduction path and exhibits good interfacial compatibility with the electrode and will not react with active lithium metal. LLZTO has excellent ionic conductivity and mechanical strength, and can also improve the ionic conductivity of the electrolyte. It can also cooperate with PFSA-Li to inhibit the growth of lithium dendrites. The two are combined and used in combination with a specific lithium salt LiTFSI, so that the obtained inorganic-organic composite solid electrolyte has high ionic conductivity, can inhibit the growth of lithium dendrites, and its stability is also improved.

[0057] (2) The preparation method of the inorganic-organic composite solid electrolyte of the present invention is simple and convenient, and does not require the introduction of electrolyte for mixing and molding, thus avoiding the safety risks caused by residual solutes and additives in the electrolyte. It also does not require expensive equipment and harsh production conditions, which is conducive to realizing mass and low-cost industrial production.

[0058] (3) The inorganic-organic composite solid electrolyte of the present invention has high ion conductivity and good stability, can inhibit the growth of lithium dendrites, and has an electrochemical window of above 4.6V. It can be adapted to most electrode materials on the market and is suitable for preparing batteries, especially lithium batteries. The obtained batteries have excellent electrochemical stability, lithium stability, cycle stability, ion migration performance and rate performance, and can be applied in the field of new energy vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 The morphology observation and XRD test spectrum of LLZTO used in the embodiments and comparative examples of the present invention are shown below; wherein, Figure 1 a and b are SEM images and XRD patterns respectively.

[0060] Figure 2 This is a physical picture of the inorganic-organic composite solid electrolyte in Example 1;

[0061] Figure 3 Graphs showing room temperature ionic conductivity of different inorganic-organic composite solid electrolytes in Examples 1-2 and Comparative Examples 1-2.

[0062] Figure 4 The electrochemical stability and lithium stability test diagram of the battery prepared by the inorganic-organic composite solid electrolyte of Example 1; wherein, Figure 4 a in the figure is the electrochemical stability diagram, Figure 4 The b in the figure is the stability diagram towards lithium.

[0063] Figure 5 The cycle stability and rate capability test diagram of the solid-state lithium metal battery prepared by the inorganic-organic composite solid electrolyte of Example 1; wherein, Figure 5 a in the figure is the cycle stability diagram, Figure 5 The b in the figure is the rate performance diagram.

[0064] Figure 6 The lithium ion migration number and ion migration activation energy diagram of the battery prepared by the inorganic-organic composite solid electrolyte of Example 1; wherein, Figure 6 a in the figure is the lithium ion migration number diagram, Figure 6 b in the figure is the activation energy diagram for ion migration. DETAILED DESCRIPTION

[0065] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0066] The preparation method of lithium lanthanum zirconium oxide (LLZTO) used in the following examples and comparative examples of the present invention comprises the following steps:

[0067] LiOH·H 2 O.La 2 O 3 、ZrO 2 and Ta 2 O 5 It was dissolved in isopropanol according to the stoichiometric ratio of 6.4:1.5:1.4:0.3, and additional LiOH·H 2 The stoichiometric ratio of O is 10% LiOH·H 2 O; after the powder is uniformly dispersed in isopropanol, it is dried at 70°C for 12h to remove the solvent isopropanol, and then calcined at 950°C for 12h to obtain LLZTO powder.

[0068] The following is a detailed description with reference to specific embodiments and comparative examples:

[0069] Example 1

[0070] The present embodiment provides an inorganic-organic composite solid electrolyte, comprising lithium perfluorosulfonate (PFSA-Li, molecular weight 770-810 g / mol), lithium lanthanum zirconium oxide (LLZTO) and LiTFSI, wherein the mass ratio of PFSA-Li, LLZTO and LiTFSI is 10:1:6; the preparation method comprises the following steps:

[0071] PFSA-Li was dissolved in N,N-dimethyldiformamide (DMF) by magnetic stirring (10000 r / min) to obtain a polymer solution, and then LLZTO was added thereto at a mass ratio of LLZTO:PFSA-Li = 2:20 and continued to be stirred (10000 r / min). After stirring evenly, LiTFSI was added according to a mass ratio of LiTFSI:PFSA-Li = 6:10 and continued to be stirred (10000 r / min) for 24 hours to obtain an electrolyte slurry (solid content of 24 wt%). Finally, the obtained electrolyte slurry was scraped onto a glass plate and dried at 60°C for 24 hours to obtain an inorganic-organic composite solid electrolyte (thickness of 16 μm).

[0072] Example 2

[0073] The present embodiment provides an inorganic-organic composite solid electrolyte, which is different from Example 1 in that different raw material mass ratios are set during the preparation process; wherein the mass ratios of LLZTO and PFSA-Li are 1:20 and 3:20, respectively; the mass ratios of LiTFSI and PFSA-Li are 1:10, 2:10, 3:10, 4:10, 5:10, 7:10, 8:10, 9:10, 10:10 and 11:10, respectively; the rest are the same as Example 1.

[0074] Comparative Example 1

[0075] This comparative example provides a composite solid electrolyte, which is different from Example 1 in that LLZTO is not added during the preparation process; the rest is the same as Example 1.

[0076] Comparative Example 2

[0077] This comparative example provides a composite solid electrolyte, which is different from Example 1 in that LiTFSI is not added during the preparation process; the rest is the same as Example 1.

[0078] Comparative Example 3

[0079] This comparative example provides a composite solid electrolyte, which is different from Example 1 in that PFSA-Li is replaced by PPO (polyphenylene ether); the rest is the same as Example 1.

[0080] The ionic conductivity of the composite solid electrolyte obtained in this comparative example is only 10 -6 ~10 -5 The ion migration number is only 0.20.

[0081] Comparative Example 4

[0082] This comparative example provides a composite solid electrolyte, which is different from Example 1 in that PFSA-Li is replaced by PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer); the rest is the same as Example 1.

[0083] The ionic conductivity of the composite solid electrolyte obtained in this comparative example at room temperature is only 10 -5 The order of magnitude, the ion migration number is only 0.26, and the first discharge capacity is 131 mAh / g.

[0084] Results

[0085] 1. LLZTO structure morphology detection:

[0086] The structure and morphology of the LLZTO used in the above examples and comparative examples were tested. The results are as follows: Figure 1 As shown. Among them, Figure 1 Figure a is the SEM image of LLZTO. Figure 1 As can be seen from a in the figure, the particle size of LLZTO used in the embodiment of the present invention and the comparative example is about 4 μm (±5%). LLZTO was placed on an XRD test bench for testing, with a scanning range of 10 to 90°. The obtained XRD spectrum is as follows: Figure 1 As shown in Figure b.

[0087] 2. Composite solid electrolyte performance test:

[0088] The composite solid electrolytes obtained in the examples and comparative examples were cut to facilitate solid-state battery assembly. The photo of the cut inorganic-organic composite solid electrolyte in Example 1 is shown in FIG. Figure 2 As shown, the whole is brown.

[0089] 1) Ionic conductivity test:

[0090] The composite solid electrolytes prepared in Examples 1-2 and Comparative Examples 1-2 were respectively clamped by two stainless steel blocking electrodes and assembled into CR2025 button batteries for testing. The test results are shown in FIG. Figure 3 As shown. Figure 3 It can be seen from the results that when the mass ratio of PFSA-Li, LLZTO and LiTFSI is 10:1:6, the corresponding room temperature lithium ion conductivity reaches a peak value of more than 1mS / cm.

[0091] It should be noted that Figure 3In the figure, the percentage of LLZTO is the percentage relative to PFSA-Li, for example, 10% LLZTO means that the mass of LLZTO is 10% of the mass of PFSA-Li, that is, the mass ratio PFSA-Li:LLZTO is 10:1; the abscissa represents the percentage of the lithium salt LiTFSI relative to the mass of PFSA-Li, for example, the abscissa 60 means that the mass of LiTFSI is 60% of the mass of PFSA-Li, that is, the mass ratio LiTFSI:PFSA=6:10.

[0092] 2) Electrochemical stability and lithium stability test:

[0093] The inorganic-organic composite solid electrolyte in Example 1 was clamped by two stainless steel blocking electrodes and assembled into a CR2025 button cell for linear sweep voltammetry test and lithium stability test. The results are as follows: Figure 4 As shown. Figure 4 As can be seen in Figure a, the battery assembled with the inorganic-organic composite solid electrolyte of Example 1 has an electrochemical stability of 4.6V (vs. Li + / Li). According to Figure 4 As shown in the results of b, it is not difficult to see that the battery assembled with the inorganic-organic composite solid electrolyte of Example 1 has a high 2 It can cycle 1200 times without short circuit at the current density, which shows that the inorganic-organic composite solid electrolyte has good compatibility with the lithium metal negative electrode and can effectively inhibit the growth of dendrites.

[0094] 3) Assembly and performance testing of solid-state lithium metal batteries:

[0095] The lithium metal negative electrode, the inorganic-organic composite solid electrolyte of Example 1 and the LFP (lithium iron phosphate) positive electrode were assembled into a solid-state lithium metal battery in an argon glove box and the cycle performance and rate performance tests were performed. Among them, the LFP positive electrode was prepared by a scraping method: LFP, conductive carbon black and binder PVDF (polyvinylidene fluoride) were uniformly mixed in a ratio of 8:1:1 in NMP (N-methylpyrrolidone) to obtain an electrode slurry, which was then scraped on an aluminum foil and dried at 120°C to prepare an LFP positive electrode for solid-state lithium metal battery assembly.

[0096] The test results of the cycle performance and rate performance of the assembled solid-state lithium metal battery are as follows: Figure 5 As shown. Among them, Figure 5a in the figure is the cycle performance test of the solid-state lithium metal battery. It can be seen that after 5 weeks of current activation at 0.2C, the test was continued at a current density of 0.5C, and the specific capacity could reach 158mAh / g. During the 250-cycle process, the capacity had almost no attenuation, and the coulombic efficiency was stable. The capacity retention rate was 80% at the 515th week, and the specific capacity curve remained stable after more than 700 cycles. Figure 5 b shows the rate performance test results, wherein the solid-state lithium metal battery still has a specific capacity of more than 130 mAh / g when the current density increases to 2C, and when the current density is restored to 0.1C, the capacity can also be restored accordingly, indicating that the solid-state lithium metal battery based on the inorganic-organic composite solid electrolyte and LFP positive electrode of the present invention has good cycle stability and rate performance.

[0097] 4) Lithium ion migration number and ion migration activation energy test:

[0098] ① The inorganic-organic composite solid electrolyte in Example 1 was clamped with two stainless steel blocking electrodes and assembled into a CR2025 button cell, and then an IT test was performed to test the starting current and stable current under constant voltage conditions, as well as the corresponding impedance. The test results are shown in Figure 6 As shown in a in , the lithium ion migration number can reach 0.42 through calculation. This means that the lithium ion transmission efficiency in the inorganic-organic composite solid electrolyte of the present invention is higher, which can effectively reduce concentration polarization, and also help to improve the charging and discharging efficiency of the battery, reduce energy loss, and meet the demand for fast charging.

[0099] ② The inorganic-organic composite solid electrolyte in Example 1 was clamped by two stainless steel blocking electrodes and assembled into a CR2025 button cell for ion migration activation energy test. The Arrhenius curve obtained is as follows: Figure 6 As shown in b in the figure, the activation energy of ion migration is calculated to be 0.134 eV. The activation energy of ion migration is a key parameter to measure the difficulty of ion migration. A lower activation energy means that the energy barrier that ions need to overcome when migrating in the electrolyte is smaller, and efficient ion transport can be achieved in a thinner electrolyte layer. It has significant advantages in improving ion conductivity, enhancing battery performance, extending battery life, improving safety and optimizing battery design.

[0100] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An inorganic-organic composite solid electrolyte, characterized in that: The invention comprises a polymer matrix, a filler and a lithium salt; the polymer matrix is ​​lithium perfluorosulfonate, the filler is lithium lanthanum zirconium oxide, and the lithium salt is LiTFSI.

2. The inorganic-organic composite solid electrolyte according to claim 1, characterized in that: The mass of the filler is 5 to 10% of the mass of the polymer matrix; And / or, the mass of the lithium salt is 40-80% of the mass of the polymer matrix.

3. The inorganic-organic composite solid electrolyte according to claim 1, characterized in that: The particle size of the lithium lanthanum zirconium oxide is 2 to 6 μm.

4. The inorganic-organic composite solid electrolyte according to any one of claims 1 to 3, characterized in that: The inorganic-organic composite solid electrolyte is in the form of a thin film; the thickness of the inorganic-organic composite solid electrolyte is 1 to 25 μm.

5. A method for preparing the inorganic-organic composite solid electrolyte according to any one of claims 1 to 4, characterized in that: The following steps are involved: The polymer matrix is ​​dissolved in an organic solvent, and fillers and lithium salts are added and mixed to obtain electrolyte slurry; the electrolyte slurry is dried to remove the solvent to obtain the inorganic-organic composite solid electrolyte.

6. The preparation method according to claim 5, characterized in that: The solid content of the electrolyte slurry is 10-80 wt %.

7. The preparation method according to claim 5, characterized in that: The drying temperature is 50-200°C.

8. The preparation method according to claim 5, characterized in that: The organic solvent includes at least one of N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide.

9. A battery, characterized in that: The invention comprises the inorganic-organic composite solid electrolyte according to any one of claims 1 to 4.

10. Use of the inorganic-organic composite solid electrolyte according to any one of claims 1 to 4 or the battery according to claim 9 in the field of new energy vehicles.

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