Composite solid electrolyte containing oxygen vacancy material and preparation method thereof

Abstract

The invention discloses a composite solid electrolyte containing an oxygen vacancy material and a preparation method thereof, and belongs to the field of lithium batteries. The electrolyte comprises a polymer matrix, a lithium salt and a functional filler, wherein the mass ratio of the polymer matrix to the lithium salt to the functional filler is 100: 60: (1-10); the functional filler is a powder material containing oxygen vacancies. The powder is limited as the functional filler adsorbs anions in the lithium salt by virtue of oxygen vacancies on the surface of the functional filler, so that more lithium ions are released, the lithium ion transference number and the ion conductivity are improved, and the powder has a larger specific surface area. The electrolyte prepared by the invention can enable the lithium symmetric battery to stably circulate for more than 2000 hours without short circuit, and shows excellent lithium dendrite inhibition capability. The method is simple in process, controllable in cost and easy for large-scale production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of lithium batteries, and particularly relates to a composite solid electrolyte containing an oxygen vacancy material and a preparation method thereof. BACKGROUND

[0002] With the increasing demand for high energy density and high safety energy storage devices worldwide, lithium metal batteries are considered as the ideal choice for the next generation of battery technology due to their extremely high theoretical specific capacity (3860 mAh g -1 ) and extremely low electrode potential (-3.04 V vs. standard hydrogen electrode). However, the organic liquid electrolyte used in traditional lithium batteries is flammable and prone to leakage, and when combined with the highly active lithium metal negative electrode, it can cause uncontrollable lithium dendrite growth, puncture the separator and cause short circuit and even fire and explosion, posing a huge safety hazard.

[0003] Solid-state electrolyte (SSE) is considered as the ultimate solution to replace liquid electrolyte and fundamentally solve the safety problem of lithium batteries due to its non-flammable, non-leakage and high mechanical strength. Among them, polymer-based solid electrolyte (such as electrolyte with PVDF-HFP as matrix) is attracting much attention due to its good flexibility, easy processing and good interface contact with electrode. However, the high crystallinity, low conductivity and low lithium ion transference number of solid-state electrolyte represented by PVDF-HFP greatly limit the development of solid-state electrolyte. This makes the traditional polymer solid-state electrolyte still have the following shortcomings: low ionic conductivity: the intrinsic ionic conductivity of traditional polymer solid-state electrolyte is much lower than that of liquid electrolyte, which limits the rate performance of the battery. Low lithium ion transference number: the simultaneous migration of anions and cations in the electrolyte leads to serious concentration polarization, increases the interface resistance, and induces lithium dendrite growth. Unstable interface with lithium metal negative electrode: prone to side reactions with lithium metal negative electrode, high interface resistance, and unable to effectively inhibit the growth of lithium dendrites, posing a serious safety hazard and limiting the cycle life of the battery.

[0004] In order to improve the performance of polymer solid-state electrolyte, the most common method in the prior art is to add inorganic nano-filler to the polymer matrix to form a composite electrolyte. These fillers are mainly divided into two categories: inert fillers and active fillers. Inert fillers such as Al2O3, SiO2, etc. They interact with the polymer chain, reduce the crystallinity of the polymer, and form a fast ion transport channel in the amorphous region. At the same time, its high mechanical modulus can inhibit lithium dendrites to a certain extent. Al2O3 and other inert fillers can improve the movement of polymer segments, but they themselves do not conduct lithium ions, and have weak interaction with lithium salt anions, which has very limited contribution to improving the lithium ion transference number. Active fillers: such as Li 0.33 La 0.557Li3V2(PO4)3, Li7La3Zr2O12 (LLZO), TiO3 (LLZTO) and other lithium ion conductors. They can conduct lithium ions themselves, thereby building an additional ion transport network to improve the overall electrical conductivity. Although active fillers such as LLZTO can conduct lithium ions, there is a problem of solid-solid interface incompatibility between the active fillers and the polymer matrix, the interface impedance is high, and the preparation process is complex and high in cost. In summary, most of the existing schemes have not effectively solved the problem of low lithium ion transference number caused by the free migration of anions in lithium salt. The migration of anions not only does not contribute to the capacity, but also exacerbates the concentration polarization and deteriorates the interface stability. SUMMARY

[0005] The purpose of the present application is to solve the problems of low ionic conductivity, low lithium ion transference number and unstable interface with lithium metal negative electrode of the existing polymer-based solid-state electrolyte, and to provide a composite solid-state electrolyte with high ionic conductivity, high lithium ion transference number and highly stable interface with lithium metal negative electrode and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A composite solid-state electrolyte containing an oxygen vacancy material, the electrolyte comprising a polymer matrix, a lithium salt and a functional filler, the mass ratio of the polymer matrix, the lithium salt and the functional filler being 100:60:1-10; the functional filler is a powder material containing oxygen vacancies. The reason for limiting it to powder is that the functional filler relies on the oxygen vacancies on its surface to adsorb the anions in the lithium salt, thereby releasing more lithium ions to improve the lithium ion transference number and ionic conductivity, and the powder has a larger specific surface area.

[0008] Further, the polymer matrix is polyvinylidene fluoride-hexafluoropropylene copolymer.

[0009] Further, the lithium salt is one of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4).

[0010] Further, the functional filler is one of barium zirconate (BaZrO3), barium phosphate (Ba3(PO4)2), strontium titanate (SrTiO3), zirconium phosphate (ZrPO4).

[0011] A preparation method of the above-mentioned composite solid-state electrolyte containing an oxygen vacancy material, the method specifically being:

[0012] Step 1, dry the polymer matrix, lithium salt and functional filler in a vacuum oven respectively;

[0013] Step 2, put the dried raw materials obtained in step 1 into a glove box filled with inert gas;

[0014] Step 3, in a glove box, the polymer matrix and lithium salt are dissolved in an organic solvent (such as NMP or DMF), stirred and dispersed to obtain a uniform polymer-lithium salt solution; the mass of the organic solvent is 8 times that of the polymer matrix;

[0015] Step 4, in a glove box, the functional filler is added to the polymer-lithium salt solution obtained in step 3, and is uniformly dispersed by ultrasonic or stirring to obtain a casting film slurry;

[0016] Step 5, in a glove box, the casting film slurry obtained in step 4 is uniformly coated on a substrate (smooth glass plate), and then placed in a vacuum oven for heating and drying to remove the solvent, thereby obtaining a composite solid electrolyte film. The coating is 200 microns, and the electrolyte film obtained after drying is 20 microns.

[0017] Further, in step 1, the temperature of the vacuum oven is set to 60-80 ℃. If the temperature is too low, the electrolyte cannot be dried in time, and if the temperature is too high, the electrolyte will be unevenly cracked when heated and dried.

[0018] Further, in step 2, the water and oxygen values of the glove box are both less than 0.01 ppm.

[0019] Further, in step 3, the dispersion time is 1-2 h, and the dispersion temperature is 20-40 ℃.

[0020] The beneficial effects of the present application relative to the prior art are:

[0021] 1. The present application proposes a lithium metal battery solid electrolyte, which not only reduces the polymer crystallinity, but also simultaneously improves the ionic conductivity by nearly 5 times (from 0.071 to 0.355 mS cm -1 ) and the lithium ion transference number from 0.589 to 0.630, solving the problem that the ionic conductivity and lithium ion transference number are difficult to be considered in the prior art.

[0022] 2. Interface stability breakthrough: compared with the prior art, the electrolyte prepared by the present application can make the lithium symmetrical battery stably cycle for more than 2000 hours without short circuit, and exhibits excellent ability to inhibit lithium dendrites.

[0023] 3. Excellent comprehensive performance of the battery: the full battery assembled by using the electrolyte of the present application has a capacity retention rate of 72.6% after 1000 cycles at a high rate of 2C, which is much higher than the 49.8% of the comparative group, and exhibits great practical application potential. The lithium ion battery electrolyte proposed by the present application has better electrochemical performance, which greatly improves the battery performance.

[0024] 4. The process of the present application is simple, the cost is controllable, and it is easy to scale up production. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 DFT calculation results of electrolyte components. (a) Electrostatic potential calculation of PVDF-HFP, TFSI - , BaZrO3. (b) Binding energy calculation of Li + -TFSI - and BaZrO3-TFSI - . (c) HOMO, LUMO energy level calculation of LiTFSI, TFSI - , PVDF-HFP, BaZrO3. (d), (e) are schematic diagrams of the principles of the present technology, (d) before adding oxygen vacancy material, (e) after adding oxygen vacancy material.

[0026] Figure 2 are the comparison diagrams of the charge-discharge cycle test results of the battery assembled by the original solid-state electrolyte and the solid-state electrolyte added with oxygen vacancy material.

[0027] Figure 3 are the comparison diagrams of the voltage-capacity curves of the charge-discharge cycle test of the battery of the original solid-state electrolyte and the solid-state electrolyte added with oxygen vacancy material at different cycle numbers.

[0028] Figure 4 are the comparison diagrams of the long-time charge-discharge cycle test results of the battery of the original solid-state electrolyte and the solid-state electrolyte added with oxygen vacancy material at a larger current.

[0029] Figure 5 are the comparison diagrams of the rate cycle test results of the battery of the original solid-state electrolyte and the solid-state electrolyte added with oxygen vacancy material.

[0030] Figure 6 are the comparison diagrams of the XRD test results of the solid-state electrolyte in the battery of the original solid-state electrolyte and the solid-state electrolyte added with oxygen vacancy material.

[0031] Figure 7 are the comparison diagrams of the conductivity test results and the lithium ion transference number test results of the battery of the original solid-state electrolyte and the solid-state electrolyte added with oxygen vacancy material.

[0032] Figure 8 are the comparison diagrams of the Fourier infrared spectrum test results of the solid-state electrolyte in the battery of the original solid-state electrolyte and the solid-state electrolyte added with oxygen vacancy material. DETAILED DESCRIPTION

[0033] The present application is further illustrated by the following examples, which are for the purpose of illustration only and are not intended to limit the scope of the present application. The test methods in the following examples, unless otherwise specified, are generally carried out under conventional conditions.

[0034] The composite solid electrolyte of the present application takes polymer and lithium salt as the main body, and adds oxygen vacancy containing material as functional filler, which effectively improves the ion conductivity and interface stability of the electrolyte. The composite solid electrolyte of the present application introduces barium zirconate (BaZrO3) containing oxygen vacancies as a functional filler in the polymer matrix, utilizes its "anion trap" effect, and synergistically and substantially improves the ion conductivity and lithium ion transference number of the solid electrolyte. The composite solid electrolyte of the present application can significantly improve the comprehensive performance of lithium metal batteries, especially the interface stability and long cycle life with lithium metal negative electrode, and is suitable for mainstream positive electrode materials such as lithium iron phosphate. The method is simple in process, controllable in cost, easy to scale up, and compatible with the existing lithium battery manufacturing process.

[0035] The present application utilizes oxygen vacancy rich material, which can adsorb anions in solid electrolyte by adsorbing negative particles through strong Lewis acidity of oxygen vacancies, thereby releasing more lithium ions, thereby improving lithium ion transference efficiency. At the same time, its inherent high conductivity can also reduce the impedance of the electrolyte, thereby improving the overall performance of the solid electrolyte, improving the cycle life and capacity retention rate of the battery, reducing the irreversibility of chemical reactions, and inhibiting the growth of lithium dendrites.

[0036] The functional filler of the present application is an oxygen vacancy containing material (barium zirconate (BaZrO3), barium phosphate (Ba3(PO4)2), strontium titanate (SrTiO3), and zirconium phosphate (ZrPO4)), which has unique physical and chemical properties. Due to the strong adsorption ability of the oxygen vacancies on the surface to lithium salt anions, the ion conductivity and lithium ion transference number of the battery are significantly improved, and the stable physical and chemical properties improve the safety and cycle life of the battery. The polymer matrix is polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), which has low reactivity with negative electrodes such as lithium metal and good electrochemical stability. The lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), and lithium perchlorate (LiClO4), which has high electrochemical stability and conductivity.

[0037] Comparative Example 1

[0038] The present embodiment provides a composite solid electrolyte, which comprises a polymer matrix and a lithium salt; the mass ratio of the polymer matrix and the lithium salt is 100:60; wherein the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the polymer matrix is polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP).

[0039] The preparation method of the composite solid electrolyte comprises the following steps:

[0040] Step 1, dry the polymer matrix, lithium salt in a vacuum oven. Among them, the vacuum oven temperature is set to 80℃.

[0041] Step 2, the dry raw materials obtained in step 1 are put into a glove box. Among them, the water and oxygen values of the glove box are all less than 0.01ppm.

[0042] Step 3, in the glove box, the polymer matrix and lithium salt are dissolved in DMF solvent, stirred at room temperature for 12h, to obtain a polymer-lithium salt solution.

[0043] Step 4, in the glove box, the casting film slurry obtained in step 3 is uniformly coated on the substrate, and vacuum dried at 80℃ for 24h, to obtain a commercial solid-state electrolyte.

[0044] Example 1

[0045] The example provides a composite solid-state electrolyte, comprising a polymer matrix, a lithium salt and a functional filler; the mass ratio of the polymer matrix, the lithium salt and the functional filler is 100:60:1; wherein the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the polymer matrix is polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), and the functional filler is barium zirconate (BaZrO3).

[0046] The preparation method of the composite solid-state electrolyte, specifically comprising the following steps:

[0047] Step 1, dry the polymer matrix, lithium salt and strontium zirconate nanoparticles in a vacuum oven. Among them, the vacuum oven temperature is set to 80℃.

[0048] Step 2, the dry raw materials obtained in step 1 are put into a glove box. Among them, the water and oxygen values of the glove box are all less than 0.01ppm.

[0049] Step 3, in the glove box, the polymer matrix and lithium salt are dissolved in NMP solvent, stirred at room temperature for 12h, to obtain a polymer-lithium salt solution.

[0050] Step 4, in the glove box, the functional filler is added to the polymer-lithium salt solution obtained in step 3, and ultrasonic treatment is carried out at room temperature for 2h to make it uniformly dispersed, to obtain a casting film slurry;

[0051] Step 5, in the glove box, the casting film slurry obtained in step 4 is uniformly coated on the substrate, and vacuum dried at 80℃ for 24h, to obtain the composite solid-state electrolyte.

[0052] Example 2

[0053] The embodiment provides a composite solid electrolyte, which comprises a polymer matrix, a lithium salt and a functional filler; the mass ratio of the polymer matrix, the lithium salt and the functional filler is 100:60:3; wherein the lithium salt is lithium hexafluorophosphate (LiPF6), the polymer matrix is polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), and the functional filler is oxygen vacancy-containing barium phosphate (Ba3(PO4)2).

[0054] The preparation method of the composite solid electrolyte comprises the following steps:

[0055] Step 1, the polymer matrix, lithium salt and barium phosphate nanoparticles are fully dried in a vacuum oven. The temperature of the vacuum oven is set to 80 DEG C.

[0056] Step 2, the dried raw materials obtained in step 1 are placed in a glove box. The water and oxygen values of the glove box are both less than 0.01 ppm.

[0057] Step 3, in the glove box, the polymer matrix and the lithium salt are dissolved in the DMF solvent, and stirred at room temperature for 12 hours to obtain a polymer-lithium salt solution.

[0058] Step 4, in the glove box, the functional filler is added to the polymer-lithium salt solution obtained in step 3, and ultrasonic treatment is carried out at room temperature for 2 hours to uniformly disperse, to obtain a casting film slurry.

[0059] Step 5, in the glove box, the casting film slurry obtained in step 4 is uniformly coated on a substrate, and vacuum dried at 80 DEG C for 24 hours to obtain the composite solid electrolyte.

[0060] Embodiment 3

[0061] The embodiment provides a composite solid electrolyte, which comprises a polymer matrix, a lithium salt and a functional filler; the mass ratio of the polymer matrix, the lithium salt and the functional filler is 100:60:5; wherein the lithium salt is lithium perchlorate (LiClO4), the polymer matrix is polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), and the functional filler is oxygen vacancy-containing strontium titanate (SrTiO3).

[0062] The preparation method of the composite solid electrolyte comprises the following steps:

[0063] Step 1, the polymer matrix, lithium salt and strontium titanate nanoparticles are fully dried in a vacuum oven. The temperature of the vacuum oven is set to 80 DEG C.

[0064] Step 2, the dried raw materials obtained in step 1 are placed in a glove box. The water and oxygen values of the glove box are both less than 0.01 ppm.

[0065] Step 3, in the glove box, the polymer matrix and lithium salt are dissolved in NMP solvent, stirred at room temperature for 12h, to obtain a polymer-lithium salt solution.

[0066] Step 4, in the glove box, the functional filler is added to the polymer-lithium salt solution obtained in step 3, and is uniformly dispersed by ultrasonic treatment at room temperature for 2h, to obtain a casting film slurry;

[0067] Step 5, in the glove box, the casting film slurry obtained in step 4 is uniformly coated on a substrate, and is vacuum dried at 80℃ for 24h, to obtain the composite solid-state electrolyte.

[0068] Example 4

[0069] The composite solid-state electrolyte provided by the embodiment comprises a polymer matrix, a lithium salt and a functional filler; the mass ratio of the polymer matrix, the lithium salt and the functional filler is 100:60:7; wherein the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the polymer matrix is polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), and the functional filler is oxygen vacancy-containing zirconium phosphate (ZrPO4).

[0070] The preparation method of the composite solid-state electrolyte comprises the following steps:

[0071] Step 1, the polymer matrix, the lithium salt and the zirconium phosphate nanoparticles are fully dried in a vacuum oven. The temperature of the vacuum oven is set to 80℃.

[0072] Step 2, the dried raw materials obtained in step 1 are placed in a glove box. The water and oxygen values of the glove box are both less than 0.01ppm.

[0073] Step 3, in the glove box, the polymer matrix and lithium salt are dissolved in NMP solvent, stirred at room temperature for 12h, to obtain a polymer-lithium salt solution.

[0074] Step 4, in the glove box, the functional filler is added to the polymer-lithium salt solution obtained in step 3, and is uniformly dispersed by ultrasonic treatment at room temperature for 2h, to obtain a casting film slurry;

[0075] Step 5, in the glove box, the casting film slurry obtained in step 4 is uniformly coated on a substrate, and is vacuum dried at 80℃ for 24h, to obtain the composite solid-state electrolyte.

[0076] Example comparison:

[0077]

[0078] As Figure 1The DFT calculation results are shown, taking barium zirconate (BaZrO3) oxygen vacancy material as an example, as shown in Figure 1 a. It can be found that the oxygen vacancy of BaZrO3 makes the surface have a significant positive region, and TFSI - as a lithium salt anion has a significant negative charge, which makes BaZrO3 adsorb the lithium salt anion, thereby promoting the dissociation of the lithium salt to release more lithium ions, thereby improving the lithium ion migration rate. At the same time, as shown in Figure 1 b, the binding energy calculation can find that the adsorption energy of BaZrO3 to TFSI - is greater than that of Li + to TFSI - , making TFSI - easier to be adsorbed by BaZrO3, thereby releasing more lithium ions. As shown in Figure 1 c, BaZrO3 has a lower LUMO energy level, which makes it have stronger Lewis acidity and can better adsorb TFSI - with electronegativity. Therefore, the mechanism of BaZrO3 and other oxygen vacancy-rich solid electrolyte additives is as shown in Figure 1 d, 1e, which can adsorb the anion in the lithium salt, thereby promoting the dissociation of the lithium salt and improving the transmission efficiency of lithium ions, thereby improving the performance of the solid electrolyte.

[0079] As shown in the test results of Figure 2 , after adding BaZrO3, the lithium metal / solid electrolyte / lithium iron phosphate battery was subjected to charge-discharge cycling at a current density of 0.5C, and the solid electrolyte lithium metal battery obtained a higher capacity retention rate and a more stable coulombic efficiency.

[0080] As shown in the test results of Figure 3 , the lithium metal / solid electrolyte / lithium iron phosphate battery was subjected to charge-discharge cycling at a current density of 0.5C, and it can be found that as shown in Figure 3 b, after adding BaZrO3, the voltage difference of the charge-discharge platform is significantly reduced (0.21 V vs. 0.11 V) compared to the control group Figure 3 (a), indicating that it has better electrochemical reversibility and lower interfacial impedance.

[0081] As shown in the test results of Figure 4As shown in the test results, when the lithium metal / solid electrolyte / lithium iron phosphate battery was charged and discharged at a current density of 2C, it was found that after adding BaZrO3, the solid electrolyte lithium metal battery achieved a higher capacity retention rate and more stable coulombic efficiency. Moreover, when the number of cycles reached 500, it was found that the extremely unstable coulombic efficiency of the control group battery caused the capacity to drop sharply. This was caused by the deterioration of the solid electrolyte. After adding BaZrO3, thanks to its oxygen vacancy adsorption of anions and its own high conductivity, this phenomenon would not occur.

[0082] like Figure 5 As shown in the test results, the lithium metal / solid electrolyte / lithium iron phosphate battery was rate cycled at a current density of 0.1C-3C. It was found that under different rate conditions, the discharge specific capacity of the battery with BaZrO3 added was greater than that of the control group.

[0083] like Figure 6 The test results show that after 50 charge-discharge cycles at a current density of 1C, a lithium metal / solid electrolyte / lithium iron phosphate battery was subjected to XRD analysis of the electrolyte. It can be seen that after the addition of BaZrO3, a clear characteristic peak belonging to BaZrO3 appeared, indicating that it was evenly mixed into the solid electrolyte. At the same time, the relative crystallinity of PVDF also decreased from 59.52% to 40.48%, indicating that barium zirconate reduced the crystallinity of PVDF and improved the ionic conductivity of the solid electrolyte.

[0084] like Figure 7 As shown in the calculation results, it can be found that thanks to the oxygen vacancy anion adsorption effect and high conductivity of BaZrO3, after adding BaZrO3, the conductivity of the solid electrolyte increased from 0.071mS / cm to 0.355mS / cm, and the lithium ion migration number also increased from 0.589 to 0.630.

[0085] like Figure 8 As shown in the test results, it can be found that thanks to the oxygen vacancy anion adsorption effect and high conductivity of BaZrO3, after adding BaZrO3, it can be found that its 1400 cm -1 and 1170cm -1 The characteristic peaks of the solid electrolyte showed an obvious red shift, which indicates that the molecular bonds of the solid electrolyte were significantly strengthened after the addition of BaZrO3, and the solid electrolyte had higher mechanical properties.

Claims

1. A composite solid electrolyte containing an oxygen vacancy material, characterized in that: The electrolyte includes a polymer matrix, a lithium salt and a functional filler, wherein the mass ratio of the polymer matrix, the lithium salt and the functional filler is 100:60:1-10; the functional filler is a powder material containing oxygen vacancies.

2. The composite solid electrolyte containing oxygen vacancy material according to claim 1, characterized in that: The polymer matrix is ​​polyvinylidene fluoride-hexafluoropropylene copolymer.

3. The composite solid electrolyte containing oxygen vacancy material according to claim 1, characterized in that: The lithium salt is one of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), and lithium perchlorate (LiClO4).

4. The composite solid electrolyte containing oxygen vacancy material according to claim 1, characterized in that: The functional filler is one of barium zirconate (BaZrO3), barium phosphate (Ba3(PO4)2), strontium titanate (SrTiO3), and zirconium phosphate (ZrPO4).

5. A method for preparing a composite solid electrolyte containing an oxygen vacancy material according to any one of claims 1 to 4, characterized in that: The method is specifically as follows: Step 1: fully drying the polymer matrix, lithium salt and functional filler in a vacuum oven; Step 2: placing the dried raw material obtained in step 1 into a glove box filled with inert gas; Step 3: In a glove box, dissolve the polymer matrix and lithium salt in an organic solvent, stir and disperse, and obtain a uniform polymer-lithium salt solution; Step 4: In a glove box, add the functional filler to the polymer-lithium salt solution obtained in step 3, and disperse it uniformly by ultrasound or stirring to obtain a casting slurry; Step 5: In a glove box, evenly coat the casting slurry obtained in step 4 on a substrate (smooth glass plate), then heat and dry it in a vacuum oven to remove the solvent, thereby obtaining a composite solid electrolyte membrane.

6. The method for preparing a composite solid electrolyte containing oxygen vacancy material according to claim 5, characterized in that: In step 1, the temperature of the vacuum oven is set to 60-80 °C.

7. The method for preparing a composite solid electrolyte containing oxygen vacancy material according to claim 5, characterized in that: In step 2, the water and oxygen values ​​in the glove box are all less than 0.01 ppm.

8. The method for preparing a composite solid electrolyte containing oxygen vacancy material according to claim 5, characterized in that: In step 3, the dispersion time is 1-2 hours, and the dispersion temperature is 20-40°C.

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