Preparation method of high dielectric constant fiber reinforced solid electrolyte

Abstract

The application relates to a preparation method of a high-dielectric-constant fiber-reinforced solid-state electrolyte, and relates to a preparation method of a solid-state electrolyte. The method comprises the following steps: S1, preparing barium strontium titanate nanofibers; and S2, preparing a fiber-reinforced solid-state electrolyte. The barium strontium titanate nanofiber skeleton is prepared by an electrostatic spinning method, and is used for constructing a quasi-solid-state electrolyte; the barium strontium titanate nanofiber skeleton has a self-supporting stable structure and a high specific surface area, significantly increases the contact area between BST and poly(vinylidene fluoride-co-hexafluoropropylene) / bifluorosulfonylimide lithium electrolyte, avoids particle aggregation, and significantly improves the electrochemical performance of the electrolyte. In particular, BST has special electrical properties as a ferroelectric body, helps to improve the interface stability in a battery, reduces the interface impedance, further improves the migration rate of lithium ions in the electrolyte, has excellent electrochemical performance, and can meet the future requirements of high energy density and safety.

Description

Technical Field

[0001] This invention relates to a method for preparing a solid electrolyte. Background Technology

[0002] The energy density of traditional lithium-ion batteries has approached its theoretical limit, and breakthroughs in new technologies are urgently needed. Lithium metal anodes, with their high theoretical energy density (3860 mAh / g) and low reduction potential (-3.04 V vs. standard hydrogen electrode), have become an ideal choice for high-energy-density energy storage, thus attracting a great deal of research attention.

[0003] Traditional lithium-ion batteries use organic liquid electrolytes, which pose safety hazards such as leakage and flammability. Furthermore, high voltage can lead to the formation of lithium dendrites, potentially causing battery explosions. To address these issues, solid-state electrolytes (SSEs) are considered an ideal alternative to liquid electrolytes, offering improved battery energy density and enhanced safety. The performance of the SSE directly determines the overall performance of the solid-state battery. In particular, obtaining SSEs with high lithium-ion conductivity at room temperature has become a key area of ​​current research.

[0004] Solid-state lithium battery electrolytes are mainly classified into three categories: inorganic solid-state electrolytes, organic polymer solid-state electrolytes, and composite solid-state electrolytes (CSEs). While inorganic solid-state electrolytes possess excellent conductivity, they suffer from high brittleness and high interfacial impedance with the electrodes; while polymer electrolytes have lower mechanical strength and lower conductivity at room temperature (10⁻⁻¹). 5 ~10⁻ 4 (S / cm). Therefore, combining the high conductivity of inorganic electrolytes with the flexibility of polymer electrolytes, developing composite solid electrolytes has become an effective strategy. However, traditional zero-dimensional or one-dimensional inorganic fillers have limited effect on improving conductivity, and excessive filler content can lead to aggregation, which in turn reduces conductivity. In addition, polymer matrices often isolate inorganic fillers, hindering the formation of continuous ion channels, thus limiting further improvements in the performance of composite electrolytes. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems existing in the prior art, and to provide a method for preparing a high dielectric constant fiber-reinforced solid electrolyte.

[0006] A method for preparing a high dielectric constant fiber-reinforced solid electrolyte is specifically carried out according to the following steps:

[0007] I. Preparation of barium strontium titanate nanofibers:

[0008] ① Dissolve polyvinylpyrrolidone in anhydrous ethanol to obtain solution A;

[0009] ② Dissolve barium acetate and strontium acetate in a mixed solution of glacial acetic acid and deionized water to obtain solution B;

[0010] ③ Under magnetic stirring conditions, solution A and solution B are mixed evenly, then tetrabutyl titanate is added and stirred evenly to obtain the precursor solution for electrospinning.

[0011] ④ The precursor solution for electrospinning is placed under vacuum for a period of time to degas, then loaded into a syringe and fixed on an electrospinning device for electrospinning. After electrospinning is completed, the resulting fiber film is placed in air and heated to 800°C~1100°C. It is then calcined for a period of time under air atmosphere and temperature of 800°C~1100°C to obtain barium strontium titanate nanofiber film.

[0012] II. Preparation of fiber-reinforced solid electrolytes:

[0013] PVDF-HFP and LiFSI were dissolved in N,N-dimethylformamide and magnetically stirred at room temperature for a period of time to obtain a backfill solution. The backfill solution was dripped onto the surface of a barium strontium titanate nanofiber film and then dried in an oven for a period of time to obtain a high dielectric constant fiber-reinforced solid electrolyte, which was then transferred to an argon-filled glove box for later use.

[0014] The principle of this invention:

[0015] This invention prepares barium strontium titanate (BST) nanofiber frameworks via electrospinning and uses them to construct quasi-solid-state electrolytes. The BST nanofiber framework possesses a self-supporting and stable structure and a high specific surface area, significantly increasing the contact area between BST and the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) / lithium bis(fluorosulfonyl)imide (LiFSI) electrolyte, thus avoiding particle aggregation and significantly improving the electrochemical performance of the electrolyte. In particular, BST, as a ferroelectric material, exhibits unique electrical properties that contribute to improved interfacial stability and reduced interfacial impedance in batteries, further enhancing the migration rate of lithium ions in the electrolyte.

[0016] Advantages of this invention:

[0017] Electrochemical performance testing showed that the high dielectric constant fiber-reinforced solid electrolyte prepared in this invention exhibited a dielectric constant as high as 6.3 × 10⁻⁻⁻⁶. 4 The ionic conductivity is S / cm, the lithium-ion transference number is 0.45, and the electrochemical window is 4.56 V. A LiFePO4||CSE||Li full cell was assembled using the high dielectric constant fiber-reinforced solid electrolyte prepared in this invention.

[0018] In the assembled LiFePO4||CSE||Li full cell, the initial discharge specific capacity at 1C rate is 136 mAh / g, and after 170 cycles, the capacity retention rate is still over 87%, demonstrating excellent cycle stability and long life.

[0019] This indicates that the high dielectric constant fiber-reinforced solid electrolyte prepared in this invention has excellent electrochemical performance and can meet future requirements for high energy density and safety. Attached Figure Description

[0020] Figure 1 The images are scanning electron microscope (SEM) images and XRD patterns. In the figure, (a) and (b) are SEM images of the barium strontium titanate nanofibers prepared in step one of Example 1, and (c) is the XRD pattern of the barium strontium titanate nanofibers prepared in step one of Example 1.

[0021] Figure 2 The ionic conductivity and lithium-ion transference number of the high dielectric constant fiber-reinforced solid electrolyte prepared in step two of Example 1 are shown.

[0022] Figure 3 The electrochemical stability window of the high dielectric constant fiber-reinforced solid electrolyte prepared in step two of Example 1;

[0023] Figure 4 The limiting current density of a lithium symmetric battery assembled using the high dielectric constant fiber-reinforced solid electrolyte prepared in step two of Example 1 and the PVH solid electrolyte prepared in Control Example 1.

[0024] Figure 5 The lifetime of a lithium-symmetric battery assembled using the high dielectric constant fiber-reinforced solid electrolyte prepared in step two of Example 1 and the PVH solid electrolyte prepared in Control Example 1 was measured.

[0025] Figure 6 The graph shows the cycling performance of the LiFePO4||CSE||Li full cell assembled using the high dielectric constant fiber-reinforced solid electrolyte prepared in step two of Example 1 at a 1C rate. Detailed Implementation

[0026] Specific Implementation Method 1: This implementation method provides a method for preparing a high dielectric constant fiber-reinforced solid electrolyte, which is specifically completed according to the following steps:

[0027] I. Preparation of barium strontium titanate nanofibers:

[0028] ① Dissolve polyvinylpyrrolidone in anhydrous ethanol to obtain solution A;

[0029] ② Dissolve barium acetate and strontium acetate in a mixed solution of glacial acetic acid and deionized water to obtain solution B;

[0030] ③ Under magnetic stirring conditions, solution A and solution B are mixed evenly, then tetrabutyl titanate is added and stirred evenly to obtain the precursor solution for electrospinning.

[0031] ④ The precursor solution for electrospinning is placed under vacuum for a period of time to degas, then loaded into a syringe and fixed on an electrospinning device for electrospinning. After electrospinning is completed, the resulting fiber film is placed in air and heated to 800°C~1100°C. It is then calcined for a period of time under air atmosphere and temperature of 800°C~1100°C to obtain barium strontium titanate nanofiber film.

[0032] II. Preparation of fiber-reinforced solid electrolytes:

[0033] PVDF-HFP and LiFSI were dissolved in N,N-dimethylformamide and magnetically stirred at room temperature for a period of time to obtain a backfill solution. The backfill solution was dripped onto the surface of a barium strontium titanate nanofiber film and then dried in an oven for a period of time to obtain a high dielectric constant fiber-reinforced solid electrolyte, which was then transferred to an argon-filled glove box for later use.

[0034] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the mass ratio of polyvinylpyrrolidone to anhydrous ethanol in step one ① is (0.5g~0.7g):(6.5mL~9mL). The other steps are the same as in Specific Implementation Method One.

[0035] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the volume ratio of glacial acetic acid to deionized water in the mixed solution of glacial acetic acid and deionized water described in step 1, ② is (3~5):(1~1). The other steps are the same as in Specific Implementation Method 1 or 2.

[0036] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the mass ratio of barium acetate in step one (②) to the volume ratio of the mixed solution of glacial acetic acid and deionized water is (2g~3g):(9mL~14mL); the mass ratio of strontium acetate in step one (②) to the volume ratio of the mixed solution of glacial acetic acid and deionized water is (0.4g~0.5g):(3.5mL~4.2mL). The other steps are the same as in Specific Implementation Methods One to Three.

[0037] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: the volume ratio of solution A to solution B in step 1.③ is (7~8):(6~7); the volume ratio of tetrabutyl titanate to the total volume of solution A and solution B in step 1.③ is (1~2):(4~9). The other steps are the same as in Specific Implementation Methods One to Four.

[0038] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: the heating rate in step one, ④ is 5°C / min to 10°C / min; the calcination time in step one, ④ is 4h to 6h. The other steps are the same as in Specific Implementation Methods One to Five.

[0039] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that the electrospinning process parameters described in step one, fourth step, are as follows: using a No. 20 needle, setting the liquid supply rate to 1 mL / h to 2 mL / h, the voltage to 18 kV to 25 kV, and the distance between the needle and the receiving electrode to 15 cm to 18 cm. Other steps are the same as in Specific Implementation Methods One through Six.

[0040] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: the degassing time in step one, fourth step is 5 to 10 minutes; the thickness of the barium strontium titanate nanofiber film in step one, fourth step is 120 μm to 150 μm. Other steps are the same as in Specific Implementation Methods One to Seven.

[0041] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: the mass ratio of PVDF-HFP to N,N-dimethylformamide in step two is (0.3g~0.5g):3mL; the mass ratio of LiFSI to N,N-dimethylformamide in step two is (0.2g~0.3g):3mL. The other steps are the same as in Specific Implementation Methods One to Eight.

[0042] Specific Implementation Method Ten: The difference between this implementation method and Specific Implementation Methods One to Nine is that the volume ratio of the backfill solution to the surface area of ​​the barium strontium titanate nanofiber film in step two is 300 μL:(2 cm²). 2 ~3cm 2 The magnetic stirring time at room temperature in step two is 10-12 hours; the drying temperature in step two is 50-55°C, and the drying time is 24-48 hours. Other steps are the same as in specific embodiments one through nine.

[0043] The beneficial effects of the present invention are verified using the following embodiments:

[0044] Example 1: A method for preparing a high dielectric constant fiber-reinforced solid electrolyte, specifically completed according to the following steps:

[0045] I. Preparation of barium strontium titanate nanofibers:

[0046] ① Dissolve 0.6g of polyvinylpyrrolidone in 7.5mL of anhydrous ethanol to obtain solution A;

[0047] ② Dissolve 2.043g of barium acetate and 0.410g of strontium acetate in a 7mL mixture of glacial acetic acid and deionized water to obtain solution B;

[0048] In step 1②, the volume ratio of glacial acetic acid to deionized water in the mixed solution of glacial acetic acid and deionized water is 4:1.

[0049] ③ Under magnetic stirring conditions, solution A and solution B are mixed evenly, then tetrabutyl titanate is added and stirred evenly to obtain the precursor solution for electrospinning.

[0050] The volume ratio of solution A to solution B in step 1③ is 15:14;

[0051] The volume ratio of tetrabutyl titanate to the total volume of solution A and solution B in step 1③ is 7:30;

[0052] ④ The precursor solution for electrospinning is placed under vacuum for 5 minutes to degas, then loaded into a syringe and fixed on an electrospinning device for electrospinning. After electrospinning, the resulting fiber film is placed in air and heated to 800°C at a heating rate of 5°C / min. It is then calcined in air at 800°C for 4 hours to obtain barium strontium titanate nanofiber film (BST nanofiber).

[0053] The electrospinning process parameters described in step 1, section 4 are as follows: using a No. 20 needle, setting the liquid supply rate to 1.5 mL / h, the voltage to 18 kV, and the distance between the needle and the receiving electrode to 15 cm.

[0054] The thickness of the barium strontium titanate nanofiber film mentioned in step 1④ is 120 μm;

[0055] II. Preparation of fiber-reinforced solid electrolytes:

[0056] 0.3 g PVDF-HFP and 0.2 g LiFSI were dissolved in 3 mL N,N-dimethylformamide and magnetically stirred at 25 °C for 12 h to obtain the backfill solution; 300 μL of the backfill solution was dripped into a surface area of ​​2 cm². 2 The surface of the barium strontium titanate nanofiber film was dried in an oven at 55°C for 24 hours to obtain a high dielectric constant fiber-reinforced solid electrolyte (BST-PVH quasi-solid electrolyte), which was then transferred to an argon-filled glove box for later use.

[0057] The microstructure of the barium strontium titanate nanofibers (BST nanofibers) prepared in step one of Example 1 is as follows: Figure 1 As shown in (a) and (b), the scanning electron microscope images are magnified at 2k and 70k, respectively. It can be seen that the precursor retains its fibrous structure after calcination, with a diameter of approximately 500 nm. Figure 1 (c) shows the X-ray diffraction (XRD) pattern of BST nanofibers. The pattern shows sharp crystal peaks, which are completely consistent with the standard crystal card PDF#97-009-0006 of BST, indicating that the synthesized material has high crystallinity.

[0058] The ionic conductivity was calculated by substituting the impedance values ​​obtained from the assembled coin cells on an electrochemical workstation into a formula. The electrolyte was punched into small discs with a diameter of 16 mm, and stainless steel sheets with a diameter of 16 mm were placed on both sides. Finally, the cells were assembled using a CR2032 battery casing. Each cell was tested at the same room temperature. The formula for calculating the ionic conductivity is as follows:

[0059]

[0060] d is the thickness of the electrolyte membrane, R is the impedance measured by electrochemical impedance spectroscopy, and S is the contact area between the electrolyte and the stainless steel sheet.

[0061] The lithium-ion transport number was measured at room temperature using two lithium metal sheets as non-blocking electrodes via chronoamperometry and AC impedance spectroscopy to determine the Li-ion transference number of the electrolyte membrane. + Ion transport number (t) Li + The potential applied to the battery is 10 mV, ranging from 1 to 10 mV. 7 Electrochemical impedance spectroscopy (EIS) of a lithium-ion symmetric battery before and after polarization was measured at Hz. The t-value of the electrolyte membrane was calculated using the formula. Li + Values. Where I0 and I... S These are the initial current and steady-state current, ΔV is the polarization potential at 10 mV, and R0 and R... S These are the initial state resistance and the steady state resistance.

[0062]

[0063] Figure 2 The high dielectric constant fiber-reinforced solid electrolyte (BST-PVH quasi-solid electrolyte) prepared in step two of Example 1 demonstrates its ionic conductivity and lithium-ion transference number (t) at 25°C. Li + The test results show that the ionic conductivity of the BST-PVH quasi-solid-state electrolyte is 6.3 × 10⁻⁶. -4 S / cm, t Li + = 0.45. These data indicate that the high dielectric constant of BST helps to enhance the dissociation of lithium salts, thereby promoting the migration of lithium ions.

[0064] Linear sweep voltammetry (LSV) is used to test the electrochemical stability window of the electrolyte. After assembling the stainless steel sheet, electrolyte, and lithium sheet into a battery in sequence, the test is performed at a rate of 0.2 mV / s within the 2-6V range until the voltage plateau of the electrolyte material changes, thus determining the high-voltage stable potential of the electrolyte membrane.

[0065] The electrochemical stability window of the BST-PVH quasi-solid electrolyte was determined by linear sweep voltammetry, see [link to relevant documentation]. Figure 3 As shown;

[0066] Figure 3 The oxidation potential is 4.56V, which meets the working requirements of lithium battery cathode materials, proving that the electrolyte maintains stable electrochemical performance under high voltage.

[0067] The lithium-symmetric battery assembled using the high-dielectric-constant fiber-reinforced solid electrolyte prepared in step two of Example 1 was specifically completed according to the following steps:

[0068] The high dielectric constant fiber-reinforced solid electrolyte (CSE) prepared in step two of Example 1 was cut into circular pieces with a diameter of 16 mm. Under the protection of an inert atmosphere (such as argon), lithium metal sheets with a diameter of 10 mm were cut as symmetrical electrodes. The lithium metal sheets, electrolyte membrane and another lithium metal sheet were assembled in sequence into a button cell mold. Stainless steel gaskets and springs were used to ensure uniform pressure. Finally, after assembly, the battery was sealed with a button cell sealing machine.

[0069] Figure 4 The limiting current density of the BST-PVH quasi-solid-state electrolyte was demonstrated by assembling a lithium-ion symmetric cell. Due to the high ionic conductivity of BST-PVH and the improved mechanical strength of the film from the addition of ceramic materials, this electrolyte effectively suppresses lithium dendrite growth at high current densities. The test results show that its limiting current density is 0.9 mA / cm². 2 This further demonstrates the good stability of BST-PVH under high current density.

[0070] Meanwhile, at 0.1 mA / cm 2 The current density and 0.1 mAh / cm 2 Battery life tests were conducted at the given areal capacity. For example... Figure 5The results showed that the lithium-ion symmetric battery assembled using the high-dielectric-constant fiber-reinforced solid electrolyte (BST-PVH quasi-solid electrolyte) prepared in step two of Example 1 exhibited a low overpotential, and the overpotential did not increase significantly after more than 1200 hours of operation. This indicates that the BST-PVH quasi-solid electrolyte formed a good interfacial contact with lithium metal, effectively suppressing the uneven deposition of lithium ions in the solid electrolyte, thereby improving the battery's stability and lifespan.

[0071] Figure 4 and Figure 5 PVH is a lithium-symmetric battery assembled using the PVH solid electrolyte prepared in Comparative Example 1, while BST-PVH is a lithium-symmetric battery assembled using the high dielectric constant fiber-reinforced solid electrolyte (BST-PVH quasi-solid electrolyte) prepared in Example 1.

[0072] The assembly of a LiFePO4||CSE||Li full cell using the high dielectric constant fiber-reinforced solid electrolyte (CSE) prepared in step two of Example 1 was carried out according to the following steps:

[0073] The high dielectric constant fiber-reinforced solid electrolyte (CSE) prepared in step two of Example 1 was cut into circular pieces with a diameter of 16 mm. A LiFePO4 positive electrode with a diameter of 12 mm and a lithium metal negative electrode with a diameter of 14 mm were also cut. Under the protection of an inert atmosphere (such as argon), the LiFePO4 positive electrode was placed at the bottom of a button cell mold, and the electrolyte membrane and lithium metal negative electrode were stacked in sequence. Then, stainless steel gaskets and springs were added, and the battery was sealed with a button cell sealing machine to complete the assembly of the LiFePO4||CSE||Li full cell.

[0074] Lithium iron phosphate was selected as the cathode material, and the cycling performance of the LiFePO4||CSE||Li full cell at 1C rate was tested. The results are as follows: Figure 6 The results show that the LiFePO4||CSE||Li full cell based on the BST-PVH quasi-solid-state electrolyte prepared in Example 1 exhibits a high discharge specific capacity of 136 mAh / g at 1C rate. After 170 cycles, the discharge specific capacity remains at 119 mAh / g, with a capacity retention exceeding 87%, and the charge-discharge efficiency is close to 100%. These results demonstrate that the BST-PVH quasi-solid-state electrolyte exhibits excellent cycle stability and can effectively improve battery performance and lifespan.

[0075] Comparing with Example 1: The preparation method of PVH solid electrolyte is specifically carried out according to the following steps:

[0076] 0.3 g PVDF-HFP and 0.2 g LiFSI were dissolved in 3 mL of N,N-dimethylformamide and magnetically stirred at 25 °C for 12 h to obtain a backfill solution. 300 μL of the backfill solution was dropped onto a glass plate and then dried in an oven at 55 °C for 24 h to obtain a solid electrolyte (PVH quasi-solid electrolyte). This solid electrolyte was then transferred to an argon-filled glove box for later use. The ionic conductivity and lithium-ion transference number (t0) of the PVH quasi-solid electrolyte at 25 °C were measured. Li + The test results show that the ionic conductivity of the PVH quasi-solid electrolyte is 4.3 × 10⁻⁶. -4 S / cm, t Li + = 0.16. The electrochemical stability window of the PVH quasi-solid-state electrolyte is 4.48 V. The limiting current density of the PVH quasi-solid-state electrolyte was tested to be 0.75 mA / cm² by assembling a lithium symmetric cell. 2 Meanwhile, at 0.1 mA / cm 2 The current density and 0.1 mAh / cm 2 At the given capacity, battery life testing was conducted for over 500 hours.

Claims

1. A method for preparing a high dielectric constant fiber-reinforced solid electrolyte, characterized in that... The preparation method is specifically carried out according to the following steps: I. Preparation of barium strontium titanate nanofibers: ① Dissolve polyvinylpyrrolidone in anhydrous ethanol to obtain solution A; ② Dissolve barium acetate and strontium acetate in a mixed solution of glacial acetic acid and deionized water to obtain solution B; ③ Under magnetic stirring conditions, solution A and solution B are mixed evenly, then tetrabutyl titanate is added and stirred evenly to obtain the precursor solution for electrospinning. ④ The precursor solution for electrospinning is placed under vacuum for a period of time to degas, then loaded into a syringe and fixed on an electrospinning device for electrospinning. After electrospinning is completed, the resulting fiber film is placed in air and heated to 800°C~1100°C. It is then calcined for a period of time under air atmosphere and temperature of 800°C~1100°C to obtain barium strontium titanate nanofiber film. II. Preparation of fiber-reinforced solid electrolytes: PVDF-HFP and LiFSI were dissolved in N,N-dimethylformamide and magnetically stirred at room temperature for a period of time to obtain a backfill solution. The backfill solution was dripped onto the surface of a barium strontium titanate nanofiber film and then dried in an oven for a period of time to obtain a high dielectric constant fiber-reinforced solid electrolyte, which was then transferred to an argon-filled glove box for later use.

2. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... The mass ratio of polyvinylpyrrolidone to anhydrous ethanol in step 1① is (0.5g~0.7g):(6.5mL~9mL).

3. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... In step 1②, the volume ratio of glacial acetic acid to deionized water in the mixed solution of glacial acetic acid and deionized water is (3~5):

1.

4. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... The mass ratio of barium acetate in step 1② to the volume ratio of the mixed solution of glacial acetic acid and deionized water is (2g~3g):(9mL~14mL); the mass ratio of strontium acetate in step 1② to the volume ratio of the mixed solution of glacial acetic acid and deionized water is (0.4g~0.5g):(3.5mL~4.2mL).

5. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... The volume ratio of solution A to solution B in step 1 ③ is (7~8):(6~7); the total volume of solution A and solution B in step 1 ③ is (4~9):(1~2) of tetrabutyl titanate.

6. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... The heating rate mentioned in step 1, ④ is 5°C / min to 10°C / min; the calcination time mentioned in step 1, ④ is 4h to 6h.

7. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... The electrospinning process parameters described in step 1, section 4 are as follows: use a No. 20 needle, set the liquid supply rate to 1 mL / h to 2 mL / h, the voltage to 18 kV to 25 kV, and the distance between the needle and the receiving electrode to 15 cm to 18 cm.

8. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... The degassing time in step 1, section 4 is 5 min to 10 min; the thickness of the barium strontium titanate nanofiber film in step 1, section 4 is 120 μm to 150 μm.

9. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... In step two, the mass ratio of PVDF-HFP to N,N-dimethylformamide is (0.3g~0.5g):3mL; the mass ratio of LiFSI to N,N-dimethylformamide in step two is (0.2g~0.3g):3mL.

10. The method for preparing a high dielectric constant fiber-reinforced solid electrolyte according to claim 1, characterized in that... The volume ratio of the backfill solution to the surface area of ​​the barium strontium titanate nanofiber film in step two is 300 μL:(2 cm²). 2 ~3cm 2 The magnetic stirring time at room temperature in step two is 10-12 hours; the drying temperature in step two is 50-55°C, and the drying time is 24-48 hours.

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