Preparation method of composite polymer quasi-solid electrolyte

Abstract

The invention belongs to the field of solid-state lithium ion battery materials, and particularly relates to a preparation method of a composite polymer quasi-solid electrolyte, which comprises the following steps: 1) mixing h-BN with ethanol and deionized water for ultrasonic treatment, dropwise adding ammonia water for ultrasonic treatment, dropwise adding TEOS liquid and stirring; filtering and washing the obtained suspension, and carrying out vacuum drying on the product; (2) mixing deionized water and absolute ethyl alcohol, adding acetic acid, uniformly stirring, adding GPTMS, stirring, adding the product in the step (1), and stirring; filtering, washing with absolute ethyl alcohol, and drying in vacuum; 3) uniformly mixing PVDF and LiTFSI, adding the mixture into a DMF solvent, and stirring to obtain a solution A; 4) performing ultrasonic treatment on the product in the step 2) in a DMF solvent to obtain a suspension B; (5) slowly pouring the suspension liquid B into the solution A, and uniformly stirring and mixing; and performing vacuum drying and cooling in a casting mold to obtain the film. The method has the advantages that the agglomeration effect of h-BN is improved, and meanwhile, the method has the advantages of improving a polymer crystal phase and promoting lithium ion migration.

Description

Technical Field

[0001] The present invention belongs to the field of solid-state lithium-ion battery materials, and particularly relates to a preparation method of a composite polymer quasi-solid electrolyte. Background Art

[0002] At present, the unstable supply, low conversion efficiency and high transportation cost of clean energy have become obstacles restricting its practical application. To address these issues, research institutions have gradually attached importance to the development of energy storage devices. Among energy storage devices, lithium-ion batteries play a major role. However, the energy density of traditional lithium-ion batteries has approached the theoretical limit. At the same time, the electrode materials in lithium-ion batteries are prone to side reactions with organic electrolytes during charge and discharge cycles, facing the risk of spontaneous combustion and explosion. To solve the safety hazards of lithium-ion batteries, solid electrolytes with high stability and low cost have received attention, and their safety is expected to fundamentally solve various problems of lithium-ion batteries.

[0003] The current research on solid electrolytes is mainly divided into inorganic solid electrolytes and polymer solid electrolytes. Among them, polymer solid electrolytes have good mechanical strength and flexibility, can meet the requirements of various battery structures, and can also operate normally after being subjected to external impacts. An ideal polymer solid electrolyte should have advantages such as good room-temperature ionic conductivity, high lithium-ion transference number, wide electrochemical stability window, excellent mechanical strength, and low cost. However, the high crystallinity of polymers at room temperature will affect the movement ability of polymer segments, thereby affecting the conduction of lithium ions.

[0004] Currently, in order to improve the high-crystallinity problem of polymer solid electrolytes, methods such as copolymerization and crosslinking are often used to modify polymers. Ghosh et al. copolymerized a PEO-PMMA block copolymer with lithium methacrylate (MAALi) to successfully prepare PEO-b-(PMMA-ran-PAAMLi), and mixed it with LiBC 4 O 8 to prepare a polymer solid electrolyte. This method can effectively improve the ordered arrangement of polymer segments to reduce the crystalline regions of polymers. However, this method has the disadvantage of being difficult to operate. Therefore, a more common modification method is to prepare organic-inorganic composite solid electrolytes.

[0005] The preparation of organic-inorganic composite solid electrolytes involves filling ceramic fillers into a polymer matrix. The ceramic fillers play multiple roles in the composite system: (1) reducing the crystallinity of the polymer and increasing the amorphous phase region; (2) enhancing the mechanical strength and thermal stability of the composite electrolyte; (3) the active groups on the filler surface enhance the dissolution of lithium salts, increase the lithium ion concentration, and promote the conduction of lithium ions. Therefore, a suitable ceramic filler is needed to modify the polymer matrix, reducing the crystallinity of the polymer at room temperature while increasing the conduction of lithium ions to meet the practical applications of solid-state batteries. Summary of the Invention

[0006] The object of the present invention is to provide a method for preparing a composite polymer quasi-solid electrolyte, which solves the problem of low lithium ion mobility caused by the high crystallinity of a single polymer electrolyte membrane at room temperature. SiO 2 is used to coat the surface of h-BN, and at the same time, epoxy groups are grafted onto the surface of SiO 2 through hydroxyl groups to prepare ceramic fillers, enabling the ceramic fillers to be well dispersed in polar solvents, thereby effectively suppressing the crystalline phase of the polymer while promoting the dissolution of lithium salts and increasing the lithium ion mobility.

[0007] To achieve the above object, the present invention is realized through the following technical solutions:

[0008] A method for preparing a composite polymer quasi-solid electrolyte includes the following steps:

[0009] 1) Preparation of h-BN@SiO 2 inorganic materials:

[0010] Take 0.5 - 2 g of h-BN solid particles, add 50 - 150 ml of ethanol and 5 - 20 ml of deionized water, mix and ultrasonicate for 5 - 20 min, then slowly add 1 - 2 ml of ammonia water and continue ultrasonication for 5 - 20 min; add 1 - 10 ml of TEOS liquid and stir for 5 - 7 h; filter the resulting suspension and wash it with absolute ethanol, and vacuum dry the product at 50 - 70 °C for 10 - 14 h to obtain h-BN@SiO 2 inorganic materials;

[0011] 2) Preparation of h-BN@SiO 2 / GPTMS ceramic fillers:

[0012] Mix 40 - 60 ml of deionized water and 40 - 60 ml of absolute ethanol, then add 10 - 30 ml of acetic acid and stir evenly. Add 1 - 3 ml of GPTMS and stir at 20 - 40 °C for 50 - 70 min. Add the h-BN@SiO prepared in step 1) 20.5 - 2 g of inorganic material, stir at 50 - 70 °C for 6 - 8 h; after filtering the obtained suspension, wash it with absolute ethanol, and vacuum dry the product at 50 - 70 °C for 10 - 14 h to obtain h-BN@SiO 2 / GPTMS ceramic filler;

[0013] 3) Prepare solution A:

[0014] Mix 0.5 - 1 g of PVDF and 0.1 - 0.5 g of LiTFSI evenly, then add them to 10 - 30 ml of DMF solvent, and mix and stir for 4 - 9 h to obtain solution A;

[0015] 4) Prepare suspension B:

[0016] Take 0.05 - 0.15 g of the ceramic filler obtained in step 2), add it to 10 - 30 ml of DMF solvent, and ultrasonicate for 20 - 60 min to obtain suspension B;

[0017] 5) Slowly pour suspension B into solution A, and continuously stir for 4 - 9 h to make them mix evenly;

[0018] 6) Pour the suspension obtained in step 5) into a casting mold, and vacuum dry it in a vacuum drying oven at 50 - 60 °C for 12 - 36 h. After cooling to room temperature, peel off the formed film to obtain the composite polymer solid electrolyte material.

[0019] The particle size of the h-BN solid particles described in step 1) is below 100 nm.

[0020] The ceramic filler described in step 4) is vacuum dried in a vacuum drying oven at 50 - 70 °C for 12 - 36 h before use.

[0021] PVDF and LiTFSI in step 3) are vacuum dried in a vacuum drying oven at 50 - 70 °C for 12 - 36 h before use.

[0022] The molecular weight of the PVDF described is 400000 - 600000.

[0023] The mold described in step 6) is a polytetrafluoroethylene circular mold with a diameter of 40 - 70 mm.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The present invention uses SiO 2 to coat h-BN, for SiO 2The grafting of epoxy groups onto the hydroxyl groups on the surface can effectively improve the agglomeration effect of h-BN, and at the same time has the advantages of improving the crystalline phase of the polymer and promoting lithium ion migration. The prepared composite polymer solid electrolyte still has a capacity retention rate of 90.11% after 300 cycles under the test conditions of a temperature of 30 °C and a current density of 1C (172 mA / g), indicating that this composite polymer solid electrolyte has promising application prospects in the field of lithium metal quasi-solid-state batteries. Description of the Drawings

[0026] Figure 1 is the preparation flow chart of the composite polymer solid electrolyte.

[0027] Figure 2 is the XRD pattern of the composite polymer solid electrolyte of Example X.

[0028] Figure 3 is the infrared test pattern of the ceramic filler of Example X.

[0029] Figure 4 is the electrochemical window test pattern of the composite polymer solid electrolyte of Example X.

[0030] Figure 5 is the assembled LiFePO of the composite polymer solid electrolyte of Example X 4 ||Li full battery long cycle test pattern.

[0031] Figure 6 is the ion conductivity test pattern of the composite polymer solid electrolyte of Example X. Detailed Embodiments

[0032] The present invention will be described in detail below with reference to the accompanying drawings of the specification, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0033] See Figure 1 , a preparation method of a composite polymer quasi-solid electrolyte, comprising the following steps:

[0034] 1) Preparation of h-BN@SiO 2 Inorganic material: Take 0.5 - 2 g of h-BN solid particles, add 50 - 150 ml of ethanol and 5 - 20 ml of deionized water, mix and ultrasonicate for 5 - 20 min, slowly add 1 - 2 ml of ammonia water and continue ultrasonication for 5 - 20 min, add 1 - 10 ml of TEOS liquid and stir for 5 - 7 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 50 - 70 °C for 10 - 14 h to obtain h-BN@SiO 2 Inorganic material.

[0035] 2) Preparation of h-BN@SiO 2 / GPTMS ceramic filler: Mix 40 - 60 ml of deionized water and 40 - 60 ml of absolute ethanol, add 10 - 30 ml of acetic acid and stir evenly, add 1 - 3 ml of GPTMS and stir at 20 - 40 °C for 50 - 70 min, add 0.5 - 2 g of the inorganic material prepared in step 1) (h-BN@SiO 2 and stir at 50 - 70 °C for 6 - 8 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 50 - 70 °C for 10 - 14 h to obtain h-BN@SiO 2 / GPTMS ceramic filler.

[0036] 3) Prepare solution A: Mix 0.5 - 1 g of PVDF and 0.1 - 0.5 g of LiTFSI evenly, then add them to 10 - 30 ml of DMF solvent and mix and stir at room temperature for 4 - 9 h to obtain solution A;

[0037] 4) Prepare suspension B: Take 0.05 - 0.15 g of the ceramic filler obtained in step 2), add it to 10 - 30 ml of DMF solvent and sonicate for 20 - 60 min to obtain suspension B.

[0038] 5) Slowly pour suspension B into solution A and continuously stir for 4 - 9 h to make them mix evenly;

[0039] 6) Cast the suspension obtained in step 5) into a polytetrafluoroethylene circular mold with a diameter of 40 - 70 mm, and vacuum dry it in a vacuum drying oven at 50 - 60 °C for 12 - 36 h. After cooling to room temperature, peel off the formed film to obtain the composite polymer solid electrolyte material.

[0040] Among them, the ceramic filler, PVDF, and LiTFSI prepared in step 2) need to be vacuum dried in a vacuum drying oven at 50 - 70 °C for 12 - 36 h before use. The molecular weight of PVDF in step 3) is 400000 - 600000.

[0041] Example 1

[0042] See Figure 1 , a preparation method of a composite polymer quasi-solid electrolyte, including the following steps:

[0043] 1) First, take 1 g of h-BN solid particles, add 100 ml of ethanol and 10 ml of deionized water and mix and sonicate for 10 min, slowly drop 1.5 ml of ammonia water and continue to sonicate for 10 min, drop 2.23 ml of TEOS liquid and stir for 6 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 55 °C for 12 h to obtain h-BN@SiO 2 inorganic material.

[0044] 2) Then, mix 50 ml of deionized water and 50 ml of absolute ethanol, add 20 ml of acetic acid and stir evenly, add 2 ml of GPTMS and stir at 30 °C for 60 min, add 1 g of the prepared h-BN@SiO 2 inorganic material and stir at 60 °C for 7 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 55 °C for 12 h to obtain h-BN@SiO 2 / GPTMS ceramic filler.

[0045] 3) Mix 0.8 g of PVDF and 0.3 g of LiTFSI evenly, then add them to 10 ml of DMF solvent, and mix and stir for 6 h to obtain Solution A.

[0046] 4) Take 0.06 g of the obtained ceramic filler, add it to 10 ml of DMF solvent and ultrasonicate for 30 min to obtain Suspension B.

[0047] 5) Slowly pour Suspension B into Solution A and continuously stir for 6 h to make them mix evenly.

[0048] 6) Cast the obtained suspension into a polytetrafluoroethylene circular mold with a diameter of 60 mm, and vacuum dry it in a vacuum drying oven at 55 °C for 24 h. After cooling to room temperature, peel off the formed film to obtain a composite polymer solid electrolyte membrane with a thickness of about 110 μm.

[0049] Example 2

[0050] See Figure 1 , a preparation method of a composite polymer quasi-solid electrolyte, comprising the following steps:

[0051] 1) First, take 1 g of h-BN solid particles, add 100 ml of ethanol and 10 ml of deionized water, mix and ultrasonicate for 10 min, slowly drop 1.5 ml of ammonia water and continue ultrasonication for 10 min, drop 4.46 ml of TEOS liquid and stir for 6 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 55 °C for 12 h to obtain h-BN@SiO 2 inorganic material.

[0052] 2) Then mix 50 ml of deionized water and 50 ml of absolute ethanol, add 20 ml of acetic acid and stir evenly, add 2 ml of GPTMS and stir at 30 °C for 60 min, add 1 g of the prepared h-BN@SiO 2 inorganic material and stir at 60 °C for 7 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 55 °C for 12 h to obtain h-BN@SiO 2 / GPTMS ceramic filler.

[0053] 3) Mix 0.8 g of PVDF and 0.3 g of LiTFSI evenly, and then add them to 10 ml of DMF solvent. Mix and stir for 6 h to obtain Solution A.

[0054] 4) Take 0.06 g of the obtained ceramic filler, add it to 10 ml of DMF solvent, and ultrasonicate for 30 min to obtain Suspension B.

[0055] 5) Slowly pour Suspension B into Solution A, and continuously stir for 6 h to make them mix evenly.

[0056] 6) Cast the obtained suspension into a polytetrafluoroethylene circular mold with a diameter of 60 mm, and vacuum dry it in a vacuum drying oven at 55 °C for 24 h. After cooling to room temperature, peel off the formed film to obtain a composite polymer solid electrolyte membrane with a thickness of about 110 μm.

[0057] Example 3

[0058] See Figure 1 , a preparation method of a composite polymer quasi-solid electrolyte, comprising the following steps:

[0059] 1) First, take 1 g of h-BN solid particles, add 100 ml of ethanol and 10 ml of deionized water, mix and ultrasonicate for 10 min, slowly add 1.5 ml of ammonia water and continue ultrasonication for 10 min, and add 6.69 ml of TEOS liquid and stir for 6 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 55 °C for 12 h to obtain h-BN@SiO 2 inorganic material.

[0060] 2) Then mix 50 ml of deionized water and 50 ml of absolute ethanol, add 20 ml of acetic acid and stir evenly, add 2 ml of GPTMS and stir at 30 °C for 60 min, add 1 g of the prepared h-BN@SiO 2 inorganic material and stir at 60 °C for 7 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 55 °C for 12 h to obtain h-BN@SiO 2 / GPTMS ceramic filler.

[0061] 3) Mix 0.8 g of PVDF and 0.3 g of LiTFSI evenly, and then add them to 10 ml of DMF solvent. Mix and stir for 6 h to obtain Solution A.

[0062] 4) Take 0.06 g of the obtained ceramic filler, add it to 10 ml of DMF solvent, and ultrasonicate for 30 min to obtain Suspension B.

[0063] 5) Slowly pour Suspension B into Solution A, and continuously stir for 6 h to make them mix evenly.

[0064] 6) Cast the obtained suspension in a polytetrafluoroethylene circular mold with a diameter of 60 mm, and vacuum dry it in a vacuum drying oven at 55 °C for 24 h. After cooling to room temperature, peel off the formed film to obtain a composite polymer solid electrolyte membrane with a thickness of about 110 μm.

[0065] Example 4

[0066] See Figure 1 , a preparation method of a composite polymer quasi-solid electrolyte, comprising the following steps:

[0067] 1) First, take 1 g of h-BN solid particles, add 100 ml of ethanol and 10 ml of deionized water, mix and ultrasonicate for 10 min, slowly add 1.5 ml of ammonia water and continue ultrasonication for 10 min, and add 8.92 ml of TEOS liquid and stir for 6 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 55 °C for 12 h to obtain h-BN@SiO 2 inorganic material.

[0068] 2) Then mix 50 ml of deionized water and 50 ml of absolute ethanol, add 20 ml of acetic acid and stir evenly, add 2 ml of GPTMS and stir at 30 °C for 60 min, add 1 g of the prepared h-BN@SiO 2 inorganic material and stir at 60 °C for 7 h. After filtering the suspension, wash it with absolute ethanol, and vacuum dry the product at 55 °C for 12 h to obtain h-BN@SiO 2 / GPTMS ceramic filler.

[0069] 3) Mix 0.8 g of PVDF and 0.3 g of LiTFSI evenly, and then add them to 10 ml of DMF solvent, and mix and stir for 6 h to obtain solution A.

[0070] 4) Take 0.06 g of the obtained ceramic filler, add it to 10 ml of DMF solvent and ultrasonicate for 30 min to obtain suspension B.

[0071] 5) Slowly pour suspension B into solution A and continuously stir for 6 h to make them mix evenly.

[0072] 6) Cast the obtained suspension in a polytetrafluoroethylene circular mold with a diameter of 60 mm, and vacuum dry it in a vacuum drying oven at 55 °C for 24 h. After cooling to room temperature, peel off the formed film to obtain a composite polymer solid electrolyte membrane with a thickness of about 110 μm.

[0073] The assembly process of a solid-state lithium-ion battery, including the preparation of electrode sheets and the process of assembling a lithium solid-state battery, is as follows:

[0074] Lithium iron phosphate, conductive agent (Super-P), and binder (PVDF) were weighed in a mass ratio of 8:1:1, ground and mixed evenly, N-methylpyrrolidone (NMP) was added to form a viscous slurry, and then evenly coated on the surface of the current collector (aluminum foil) with a coater.

[0075] Place the aluminum foil coated with the slurry in a vacuum oven at 120°C and bake for 12 hours to remove the NMP solvent. Finally, cut the aluminum foil into circular positive electrode sheets with a diameter of 11 mm for use. The composite polymer electrolyte membrane is cut into discs with a diameter of 15.6 mm. The order of encapsulating the battery is as follows: negative electrode shell, lithium sheet, diaphragm, positive electrode sheet, gasket, spring sheet, positive electrode shell. During the assembly process, 6 microliters of lithium battery electrolyte are dripped on the surface of the composite polymer electrolyte membrane. The entire process of encapsulating lithium metal solid-state batteries is carried out in a glove box filled with argon, and the water and oxygen contents are less than 0.1 ppm.

[0076] Table 1

[0077]

[0078]

[0079] Table 1 is the composite solid electrolyte assembly of LiFePO in Examples 1, 2, 3, and 4. 4 || Li full battery long cycle test comparison, their first cycle discharge specific capacities are 135.0mAh / g, 138.6mAh / g, 136.9mAh / g, 135.4mAh / g, and the 300th cycle capacity retention rates are 88.96%, 90.11%, 87.29%, 86.78%, respectively, indicating that the composite solid electrolyte with the addition of this ceramic filler has good cycle stability, h-BN and SiO 2 It can improve the amorphous phase region of the polymer, but if SiO 2 Excessive coating may hinder the Lewis acid properties of h-BN, thereby affecting the lithium ion concentration inside the electrolyte.

[0080] Depend on Figure 2 It can be seen that by comparing the XRD spectrum of the original h-BN, the prepared ceramic filler has no impurity peaks, and a subtle bun peak appears between 20° and 25°, corresponding to the amorphous SiO 2 , and the diffraction intensity of the h-BN characteristic peak decreased, indicating that SiO 2 Coated on the surface, reducing the crystallinity.

[0081] Depend on Figure 3 It can be seen that the FT-IR test of ceramic filler is at 1390.4cm -1 Corresponding to the in-plane stretching vibration of the BN bond, 1079.4 cm-1 is the asymmetric stretching vibration of Si-O-Si, at 930 cm -1 which may be related to the stretching vibration of the epoxy group, proving that after the coating grafting experiment, the surface of h-BN is coated with SiO 2 and grafted with epoxy groups.

[0082] From Figure 4 it can be seen that the oxidation decomposition potential of the composite solid electrolyte reaches 4.8 V, which can well meet the application requirements of the lithium iron phosphate cathode and meet the actual application of lithium batteries.

[0083] From Figure 5 it can be seen that at the test temperature of 60 °C, the ionic conductivity of the composite solid electrolyte prepared in Example 2 is 5.84×10 -4 S / cm, indicating that h-BN and SiO 2 can improve the amorphous phase region of the polymer, and at the same time h-BN can provide Lewis acidic groups to increase the lithium ion concentration in the electrolyte system.

[0084] From Figure 6 it can be seen that in Example 2 at 30 °C, the discharge specific capacity of the first cycle tested at a current density of 1C is 138.6 mAh / g, and the capacity retention rate after 300 cycles is 90.11%, proving that the composite solid electrolyte prepared in this Example 2 has good cycle stability.

[0085] When using single h-BN as a filler to prepare a composite polymer solid electrolyte, due to its Lewis acid properties, it can improve the dissolution of lithium salts, but it is limited by filler agglomeration. When the content of h-BN is high, it will agglomerate together and instead hinder the conduction of lithium ions. While using single SiO 2 as a filler to prepare a composite polymer solid electrolyte only has the effect of improving the crystalline phase. The present invention uses SiO 2 to coat h-BN, and grafting epoxy groups onto the hydroxyl groups on the surface of SiO 2 can well improve the agglomeration effect of h-BN, and at the same time has the advantages of improving the crystalline phase of the polymer and promoting the migration of lithium ions. The prepared composite polymer solid electrolyte still has a capacity retention rate of 90.11% after 300 cycles under the test conditions of a temperature of 30 °C and a current density of 1C (172 mA / g), indicating that this composite polymer solid electrolyte has promising application prospects in the field of lithium metal quasi-solid state batteries.

[0086] Compared with the pure PVDF solid electrolyte, the prepared composite polymer solid electrolyte shows a higher lithium ion conductivity for this ceramic filler (at 60 °C, the lithium ion conductivity reaches 3.14×10 -4 S / cm to 5.84×10 -4S / cm, good cycling performance (in a lithium-ion solid electrolyte with lithium iron phosphate as the positive electrode, the discharge specific capacity after 300 cycles at a current density of 1C is 117 - 125 mAh / g, and the capacity retention rate is 86% - 91%). Through testing, the reason for the excellent electrochemical performance of this ceramic filler in the PVDF-based composite polymer solid electrolyte was explained - inhibiting the formation of the polymer crystalline phase, improving the lithium-ion mobility, and at the same time, the Lewis acidic groups of h-BN can help increase the lithium-ion concentration in the electrolyte system.

Claims

1. A method for preparing a composite polymer quasi-solid electrolyte, characterized in that: The following steps are involved: 1) Preparation of h-BN@SiO2 inorganic materials: Take 0.5-2g of h-BN solid particles, add 50-150ml of ethanol and 5-20ml of deionized water, mix and ultrasonicate for 5-20min, then slowly drop 1-2ml of ammonia water and continue ultrasonicate for 5-20min; drop 1-10ml of TEOS liquid and stir for 5-7h; filter the obtained suspension and wash with anhydrous ethanol, and vacuum dry the product at 50-70°C for 10-14h to obtain h-BN@SiO2 inorganic material; 2) Preparation of h-BN@SiO2 / GPTMS ceramic filler: Mix 40-60 ml of deionized water and 40-60 ml of anhydrous ethanol, add 10-30 ml of acetic acid and stir evenly, add 1-3 ml of GPTMS and stir at 20-40° C. for 50-70 min, add 0.5-2 g of the h-BN@SiO2 inorganic material prepared in step 1), and stir at 50-70° C. for 6-8 h; filter the obtained suspension and wash it with anhydrous ethanol, and vacuum dry the product at 50-70° C. for 10-14 h to obtain h-BN@SiO2 / GPTMS ceramic filler; 3) Preparation of solution A: 0.5-1 g of PVDF and 0.1-0.5 g of LiTFSI were mixed evenly, then added into 10-30 ml of DMF solvent, and mixed and stirred for 4-9 hours to obtain solution A; 4) Preparation of suspension B: Take 0.05-0.15 g of the ceramic filler obtained in step 2), add it to 10-30 ml of DMF solvent, and ultrasonicate it for 20-60 min to obtain suspension B; 5) Slowly pour suspension B into solution A and continue stirring for 4 to 9 hours to mix evenly; 6) Casting the suspension obtained in step 5) into a mold, and vacuum drying in a vacuum drying oven at 50-60° C. for 12-36 hours, and peeling off the formed film after cooling to room temperature to obtain a composite polymer solid electrolyte material.

2. The method for preparing a composite polymer quasi-solid electrolyte according to claim 1, characterized in that: The particle size of the h-BN solid particles described in step 1) is less than 100 nm.

3. The method for preparing a composite polymer quasi-solid electrolyte according to claim 1, characterized in that: The ceramic filler in step 4) is vacuum dried in a vacuum drying oven at 50-70° C. for 12-36 hours before use.

4. The method for preparing a composite polymer quasi-solid electrolyte according to claim 1, characterized in that: In step 3), PVDF and LiTFSI are vacuum dried in a vacuum drying oven at 50-70° C. for 12-36 h before use.

5. The method for preparing a composite polymer quasi-solid electrolyte according to claim 1, characterized in that: The molecular weight of the PVDF is 400,000-600,000.

6. The method for preparing a composite polymer quasi-solid electrolyte according to claim 1, characterized in that: The mold described in step 6) is a polytetrafluoroethylene circular mold with a diameter of 40 to 70 mm.

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