A dual-ion regulation composite solid electrolyte, a preparation method and application thereof

Abstract

The application belongs to the technical field of electrochemical energy storage, and provides a dual-ion regulated composite solid electrolyte, a preparation method and application thereof. The electrolyte is a four-component composite system composed of a rigid framework, a polyethylene oxide matrix, a functionalized covalent organic framework filler and a lithium salt. The functionalized covalent organic framework filler is a covalent organic framework cooperatively modified by methoxy grafted on the inner wall of the pore and imidazole cations grafted on the surface of the framework. The weak coordination between methoxy and Li + promotes the dissociation of the lithium salt and the Li + transport, and the imidazole cations anchor the anions through electrostatic interaction, so that the two achieve precise regulation of dual ions. The electrolyte has a room temperature ionic conductivity of 2.83*10 ‑4 S·cm ‑1 , and the lithium ion transference number is increased to 0.73, and the electrolyte has excellent mechanical strength and lithium metal compatibility. The application also discloses a solid-state lithium ion battery using the electrolyte. The battery has a capacity retention rate of 83% or more after 1C rate cycling for 1000 times, and is suitable for high-safety and long-life energy storage equipment.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage technology, specifically relating to a dual-ion regulated composite solid electrolyte, its preparation method and application, and particularly to a polyoxyethylene composite solid electrolyte using functionalized covalent organic framework materials as fillers, and its application in high-safety solid-state lithium-ion batteries. Background Technology

[0002] With the continued growth in demand for high-energy-density and high-safety batteries, solid-state lithium batteries are considered a core direction for next-generation energy storage technology. Polyethylene oxide (PEO)-based solid electrolytes have been widely studied due to their good compatibility with lithium metal, excellent film-forming properties, and flexibility. However, inherent defects of PEO-based electrolytes restrict their industrialization: firstly, the lithium-ion transference number is low (typically <0.3), and the ether oxygen groups on the PEO chain... It has a strong coordination effect, resulting in a much faster migration rate of lithium salt anions than... Firstly, it causes severe concentration polarization; secondly, its low ionic conductivity at room temperature and the high crystallinity of PEO at room temperature restrict chain segment movement, hindering Li + Thirdly, its mechanical strength is insufficient, making it difficult to effectively suppress the growth of lithium dendrites and posing a short-circuit risk.

[0003] Introducing inorganic fillers can reduce the crystallinity of PEO and create additional ion channels, but traditional fillers have limited functionality and poor interfacial compatibility with PEO, making it impossible to achieve the desired results simultaneously. Transport enhancement and anion anchoring. Covalent organic frameworks (COFs), with their regular channels and designability, offer new ideas for high-performance fillers. However, existing COF-based electrolytes have significant shortcomings: ① Limited functional modification, such as using only imidazole cations for single modification, which cannot achieve synergistic regulation by two ions; ② Incomplete system design, such as dual-modified COF electrolytes being quasi-solid systems containing polycarbonate (PC) additives, lacking a PEO matrix and rigid framework, resulting in insufficient safety and mechanical strength; ③ Lack of site-specific design, such as the "imidazole + sulfonic acid" dual-modified COF which does not distinguish modification sites, and the matrix is ​​PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene), which is incompatible with PEO. Significant differences in compatibility; ④ Lack of rigid framework support leads to COF agglomeration, insufficient mechanical strength (tensile strength <1.5MPa), and poor lithium dendrite suppression effect.

[0004] Therefore, a quaternary pure solid system of "dual-site specific modification of COF+PEO matrix + rigid framework + lithium salt" was developed, through "methoxy-promoted" The dual-ion synergistic regulation of "transportation + imidazole cation anchoring anion" solves the problems of poor room temperature performance and insufficient mechanical strength of existing electrolytes, which is a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a dual-ion regulated composite solid electrolyte, its preparation method, and its application, aiming to overcome the performance bottlenecks of existing electrolytes through precise structural design and system synergy.

[0006] This invention provides a dual-ion regulated composite solid electrolyte, comprising a rigid framework, a polyethylene oxide matrix, a functionalized covalent organic framework (COF) filler, and a lithium salt, forming a quaternary composite system. The functionalized COF filler is a covalent organic framework synergistically modified with methoxy groups grafted onto the inner wall of the pores and imidazole cations grafted onto the surface of the framework, wherein the molar ratio of the methoxy groups to the imidazole cations is 1-3:1. The electrolyte is prepared by the interaction of methoxy groups with... Weak coordination promotes Transport is achieved by anchoring the anion through the electrostatic interaction between the imidazole cation and the anion, thus realizing the synergistic regulation of the two ions.

[0007] Furthermore, the rigid framework is a polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) or polyacrylonitrile (PAN) electrospun porous membrane, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the vinyl oxide body is polyethylene oxide (PEO), and the mass percentage of each component in the quaternary composite system is: rigid framework 10~20%, vinyl oxide body 50~70%, lithium salt 15~25%, and functionalized covalent organic framework filler 0.3~0.9%.

[0008] Furthermore, the amount of the functionalized covalent organic framework filler added is 0.3%-0.9% of the total mass of the rigid framework, polymer matrix, lithium salt, and functionalized covalent organic framework filler.

[0009] Furthermore, when the molar ratio of the methoxy group to the imidazole cation is 1:1, the lithium-ion transference number is ≥0.73, and the ionic conductivity at room temperature (25°C) is ≥ .

[0010] Furthermore, the rigid framework has a pore size of 1.0~3.0μm and a porosity of 70~85%, forming a continuous ion transport channel with the polyethylene oxide body to inhibit the agglomeration of functionalized covalent organic framework fillers (dispersed particle size <200nm).

[0011] Furthermore, the specific surface area of ​​the functionalized covalent organic framework filler is The pore size is concentrated in the range of 3.0~4.0 nm, which is Provides a directional transmission channel.

[0012] Furthermore, the functionalized covalent organic framework filler is synthesized by a solvothermal method, specifically: a monomer with methoxy and aldehyde groups and an ionic liquid with amino and imidazole groups are dissolved in a mixed solvent of mesitylene and dioxane at a certain molar ratio, and then o-dichlorobenzene, n-butanol and acetic acid are added sequentially. After freezing and sealing, the mixture is statically reacted at 120°C for 3-5 days. After the reaction is completed, the mixture is washed and dried to obtain the filler.

[0013] Furthermore, a method for preparing a dual-ion-regulated composite solid electrolyte includes the following steps:

[0014] Step 1: Dissolve polyethylene oxide and lithium salt in acetonitrile or N,N-dimethylformamide, and stir magnetically until completely dissolved to obtain solution A; Step 2: Add the functionalized covalent organic framework filler to solution A at a mass percentage of 0.3-0.9%, disperse it ultrasonically for 20-60 minutes, and then mechanically stir for 4-8 hours to obtain a uniform slurry B; Step 3: Pour slurry B onto a rigid skeleton, volatilize at 40-60℃ for 4-8 hours, and then vacuum dry at 60-80℃ for 12-24 hours to obtain a dual-ion regulated composite solid electrolyte.

[0015] Furthermore, the application of a dual-ion-regulated composite solid electrolyte in the preparation of a solid-state lithium-ion battery, wherein the solid-state lithium-ion battery includes a positive electrode, a negative electrode, and an electrolyte, and the electrolyte is a dual-ion-regulated composite solid electrolyte.

[0016] Furthermore, the room temperature ionic conductivity of the dual-ion regulated composite solid electrolyte is ≥ The lithium-ion transference number is ≥0.73.

[0017] Furthermore, the active material of the positive electrode is lithium iron phosphate or nickel-cobalt-manganese ternary material, and the negative electrode is metallic lithium or graphite.

[0018] The preparation method of this invention is simple and controllable, and the obtained electrolyte achieves high room temperature conductivity. The synergistic effect of high mobility (≥0.73), high mechanical strength, and long cycle stability allows it to be applied to solid-state lithium-ion batteries, achieving a capacity retention rate of over 83% after 1000 cycles at 1C rate, combining safety and practicality.

[0019] The present invention has the following beneficial effects: (1) The core innovation of this invention lies in constructing a rigid framework-PEO-bifunctionalized COF-lithium salt quaternary composite system to achieve dual-ion synergistic regulation: ① The methoxy group of the bifunctionalized COF is grafted onto the inner wall of the pore, and the coordination energy is reduced through weak coordination (DFT calculation coordination energy 1.0-1.2eV). Lithium salt dissociation energy barrier, promotes Rapid transport; imidazole cations are grafted onto the framework surface and anchor TFSI⁻ anions via electrostatic interaction (interaction energy -3.0-3.2 eV), reducing concentration polarization caused by anion migration. The synergistic effect is optimal when the molar ratio of the two is 1:1; ② Rigid frameworks (such as PAN electrospun membranes) not only improve the mechanical strength of the electrolyte (tensile strength ≥3.5 MPa) but also inhibit COF aggregation (dispersed particle size <200 nm), forming continuous ion channels with the PEO matrix, solving the problem of ion transport obstruction caused by the high crystallinity of PEO; ③ The quaternary system synergistically achieves high room temperature conductivity ( It features high mobility (≥0.73), high mechanical strength, and long-term cycling stability (83% retention rate after 1000 cycles at 1C), overcoming the shortcomings of existing single-system performance.

[0020] (2) Compared with the prior art, the advantages of the present invention are: high lithium-ion transport number, with imidazole cations strongly anchoring anions through electrostatic interaction, significantly reducing the migration rate of anions; high ionic conductivity, with the introduction of ionic covalent organic framework fillers increasing the content of amorphous regions and promoting the movement of polyoxyethylene chain segments; at the same time, the regular nanopores of the ionic covalent organic framework itself can serve as rapid lithium-ion transport channels; methyl groups further promote the dissociation of lithium salts; the synergistic effect of these three factors gives the composite electrolyte a high ionic conductivity (up to 100%) at room temperature. (Scale). Excellent electrochemical stability: The composite electrolyte exhibits good interfacial stability with the lithium metal anode, effectively suppressing lithium dendrite growth and extending battery cycle life; Enhanced mechanical properties: The preparation of a rigid polyacrylonitrile fiber skeleton by electrospinning improves the mechanical strength and thermal stability of the electrolyte, making it easier to process into films. Attached Figure Description

[0021] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures: Figure 1 The images shown are SEM images and EDS elemental distribution diagrams of the functionalized covalent organic framework filler of Example 1 of this invention, wherein: Figure 1 In the image, A represents the SEM image, scale bar: 500nm; Figure 1 B in the diagram represents the distribution of EDS elements.

[0022] Figure 2 The images show a surface SEM comparison of the solid electrolyte prepared in Comparative Example 2 and the dual-ion regulated composite solid electrolyte prepared in Example 4 of this invention. Scale bar: 50 μm. Figure 2 In this example, A represents Comparative Example 2; Figure 2B in the example is Example 4.

[0023] Figure 3 The Arrhenius fitting curves of ionic conductivity for Example 4 (CPE-ICOF), Comparative Example 1 (CPE), and Comparative Example 2 (CPE-COF) of the present invention are shown (Activation energy of Example 4: 0.234 eV; Activation energy of Comparative Example 1: 0.252 eV; Activation energy of Comparative Example 2: 0.244 eV).

[0024] Figure 4 The graphs show the rate performance of lithium iron phosphate batteries assembled with dual-ion regulated composite solid electrolytes (CPE-ICOF3, CPE-ICOF6, CPE-ICOF9) and Comparative Example 1 (CPE) at different rates.

[0025] Figure 5 The graph shows the long-cycle performance of lithium iron phosphate batteries assembled in Example 4 (CPE-ICOF), Comparative Example 1 (CPE), and Comparative Example 2 (CPE-COF) at 1C rate.

[0026] Figure 6 A diagram illustrating the synergistic mechanism of functionalized covalent organic framework fillers provided in embodiments of the present invention.

[0027] Figure 7 The diagram shows the median voltage and LED illumination of the solid-state pouch cell assembled in Embodiment 4 (CPE-ICOF) of the present invention. Detailed Implementation

[0028] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0030] Example 1: The functionalized covalent organic framework filler was synthesized using a solvothermal method, specifically as follows: Monomers containing methoxy and aldehyde groups were dissolved in a mixed solvent of mesitylene and dioxane (volume ratio 1:1) with ionic liquids containing amino and imidazole groups at a molar ratio of methoxy monomer: aldehyde monomer: imidazole ionic liquid = 1:0.7:1. Then, 1.2 ml of o-dichlorobenzene, 1 ml of n-butanol, and 0.2 ml of acetic acid were added sequentially. The heat-resistant glass tube was quickly placed in a liquid nitrogen bath for freezing, sealed, and statically reacted at 120 °C for 3 days. After the reaction was completed, the resulting solid powder was filtered and washed with saturated sodium carbonate aqueous solution and tetrahydrofuran. The powder was then vacuum dried at 70 °C for 12 hours to obtain a reddish-brown solid powder, which is the functionalized covalent organic framework filler.

[0031] The prepared functionalized covalent organic framework filler has a specific surface area of ​​200~250m² / g and a pore size of 2~4nm.

[0032] SEM images and EDS elemental distribution maps of functionalized covalent organic framework fillers are shown below. Figure 1 As shown, the results indicate that C, O, and N elements are uniformly distributed in the material, demonstrating the successful synthesis of the functionalized covalent organic framework filler.

[0033] Example 2: The steps are the same as in Example 1, except that imidazole ionic liquid is not added to the monomer to synthesize a covalent organic framework material.

[0034] Example 3: The preparation of polyacrylonitrile spun fiber membranes is as follows: Polyacrylonitrile was dissolved in N,N-dimethylformamide (DMF) at a mass ratio of 1:10 (polyacrylonitrile:DMF). The mixture was stirred continuously for 16 hours to obtain a homogeneous solution. The electrospinning parameters were configured as follows: applied voltage 22 kV, solution feed rate 0.04 mL / min, and collector rotation speed set to 400 rpm. The electrospinning process lasted for 2 hours. Subsequently, the prepared polyacrylonitrile electrospun porous membrane was placed in a vacuum drying oven for 10 hours to remove residual solvent.

[0035] Example 4: The preparation of dual-ion regulated composite solid electrolytes is as follows: Polyethylene oxide (molecular weight 400,000-800,000) and LiTFSI were dissolved in acetonitrile solvent and magnetically stirred until completely dissolved to obtain a homogeneous solution A. The functionalized covalent organic framework filler prepared in Example 1 (methoxy monomer: aldehyde monomer: imidazole ionic liquid = 1:0.7:1) was added at 0.6% of the total mass, and ultrasonically dispersed for 20 minutes and mechanically stirred for 4 hours to ensure uniform dispersion, resulting in slurry B. Slurry B was poured onto the polyacrylonitrile electrospun porous membrane of Example 3, and the solvent was evaporated in a vacuum drying oven for 8 hours to completely remove residual solvent. It was then vacuum dried at 60°C for 12 hours to obtain a flexible dual-ion regulated composite solid electrolyte (mass percentage of each component: polyacrylonitrile 13%, polyethylene oxide 64.3%, lithium salt 22.1%, functionalized covalent organic framework filler 0.6%).

[0036] The synergistic mechanism diagram of functionalized covalent organic framework fillers is shown below. Figure 6 As shown, the results indicate that functionalized covalent organic framework fillers can effectively promote the dissociation of lithium salts and provide efficient lithium-ion migration channels by introducing lithiophilic and anionophilic groups.

[0037] Example 5: The preparation of dual-ion regulated composite solid electrolytes with different amounts of functionalized covalent organic framework fillers was carried out using the same process as in Example 3. The amount of functionalized covalent organic framework filler added was 0.3% (CPE-ICOF3), with the following mass percentages of components: polyacrylonitrile 13%, polyethylene oxide 64.6%, lithium salt 22.1%, and functionalized covalent organic framework filler 0.3%; the amount of functionalized covalent organic framework filler added was 0.9% (CPE-ICOF9), with the following mass percentages of components: polyacrylonitrile 13%, polyethylene oxide 64%, lithium salt 22.1%, and functionalized covalent organic framework filler 0.9%; to investigate the effect of the functionalized covalent organic framework filler content on performance.

[0038] Example 6: The experiment to optimize the ratio of bifunctionalized COF groups is as follows: Bifunctionalized COFs with different methoxy to imidazole cation molar ratios were prepared: COF-1 (methoxy:imidazole cation = 1:1), COF-2 (methoxy:imidazole cation = 2:1), and COF-3 (methoxy:imidazole cation = 3:1), with the remaining preparation conditions the same as in Example 1; dual-ion regulated composite solid electrolytes were prepared according to the method in Example 4, and were respectively designated as electrolyte-1 (COF-1 + polyethylene oxide), electrolyte-2 (COF-2 + polyethylene oxide), and electrolyte-3 (COF-3 + polyethylene oxide).

[0039] Comparative Example 1: Prepare a polyoxyethylene composite solid electrolyte without any fillers.

[0040] The rate performance of dual-ion regulated composite solid electrolytes (CPE-ICOF3, CPE-ICOF6, CPE-ICOF9) prepared with different amounts of functionalized covalent organic framework fillers and Comparative Example 1 (CPE) is as follows: Figure 4 As shown, the results indicate that the dual-ion regulated composite solid electrolytes (CPE-ICOF3, CPE-ICOF6, and CPE-ICOF9) have higher discharge specific capacity and better capacity retention than Comparative Example 1 (CPE) at different rates, especially at a high rate of 5C, demonstrating that the addition of functionalized covalent organic framework fillers is more conducive to the rapid charge and discharge of the battery.

[0041] Comparative Example 2: Prepare a covalent organic framework filler without any specific functional groups, and follow the same steps as in Example 4 to prepare a solid electrolyte without a covalent organic framework containing specific functional groups.

[0042] The SEM comparison results of the dual-ion regulated composite solid electrolyte prepared in Example 4 and the solid electrolyte prepared in Comparative Example 2 are as follows: Figure 2 As shown, the results indicate that the surface of the dual-ion regulated composite solid electrolyte is smoother, proving that the introduction of functionalized covalent organic framework filler improves the formation of polyoxyethylene amorphous regions and forms a denser film surface.

[0043] The Arrhenius fitting curves of the ionic conductivity of Example 4 (CPE-ICOF), Comparative Example 1 (CPE), and Comparative Example 2 (CPE-COF) are shown below. Figure 3 As shown, the results indicate that at all test temperatures (25-80℃), the ionic conductivity of Example 4 (CPE-ICOF) was significantly higher than that of Comparative Example 1 (CPE) and Comparative Example 2 (CPE-COF); Example 4 (CPE-ICOF) exhibited the highest ionic conductivity at room temperature, reaching [value missing]. Furthermore, its activation energy is the lowest, proving that an appropriate amount of functionalized covalent organic framework filler is more conducive to constructing efficient ion transport channels.

[0044] Comparative Example 3: The composite solid electrolyte of polyethylene oxide and a single methoxy-modified covalent organic framework was prepared. Except that the ionic covalent organic framework filler was replaced with a covalent organic framework filler that was only modified with methoxy groups, the other preparation steps were the same as in Example 4.

[0045] Comparative Example 4: The composite solid electrolyte of polyethylene oxide and a single imidazole cation modified covalent organic framework was prepared. Except that the ionic covalent organic framework filler was replaced with a covalent organic framework filler modified only with imidazole cation, the other preparation steps were the same as in Example 4.

[0046] Application Example 1: This application example provides a set of fabrication and practical application tests for solid-state pouch cells:

[0047] Cut the solid electrolyte into sheets, so as to The soft-pack battery was assembled in an argon-protected glove box using lithium foil as the two electrodes; its voltage was measured to be 3.30V with a voltmeter, and its practicality was tested after the first charge.

[0048] Experimental methods: The electrochemical performance of the solid electrolytes prepared in Example 4 and Comparative Examples 1-4, including ionic conductivity and lithium-ion transference number, was tested. The test results are shown in Table 1.

[0049] Table 1 Electrochemical performance test results

[0050] The electrochemical performance of the solid electrolytes prepared in each Example 6 was tested for ionic conductivity and lithium-ion transference number. The test results are shown in Table 2.

[0051] Table 2 Electrochemical performance test results

[0052] When the molar ratio of methoxy to imidazole cations is 1:1, the synergistic effect of the two ions is optimal, and the overall performance of the electrolyte is the best.

[0053] The median voltage and LED illumination of the solid-state pouch cell assembled in Example 4 (CPE-ICOF) are shown in the figure. Figure 7 As shown, the results indicate that the solid-state pouch cell based on Example 4 (CPE-ICOF) has an initial voltage of 3.30V and can light up an LED after the first charge, confirming the possibility of dual-ion regulated composite solid electrolyte as a practical application.

[0054] Full battery performance Using lithium metal as the positive electrode and lithium metal as the negative electrode, Examples 4 (CPE-ICOF), 1 (CPE), and 2 (CPE-COF) are electrolyte-assembled batteries. After 1000 cycles at 1C rate and room temperature, the long-cycle performance results of Examples 4 (CPE-ICOF), 1 (CPE), and 2 (CPE-COF) are as follows: Figure 5 As shown, the results indicate that after 1000 cycles at 1C, the capacity retention of Example 4 (CPE-ICOF) is significantly higher than that of Comparative Example 1 (CPE) and Comparative Example 2 (CPE-COF), with a capacity retention of over 83%, demonstrating excellent cycling stability.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-ion-regulated composite solid electrolyte, characterized in that, A quaternary composite system is composed of a rigid framework, a polyethylene oxide matrix, a functionalized covalent organic framework filler, and a lithium salt; the functionalized covalent organic framework filler is a covalent organic framework synergistically modified with methoxy groups grafted onto the inner wall of the pores and imidazole cations grafted onto the surface of the framework, wherein the molar ratio of the methoxy groups to the imidazole cations is 1~3:

1.

2. The dual-ion regulated composite solid electrolyte according to claim 1, characterized in that, The rigid framework is a polyvinylidene fluoride-hexafluoropropylene or polyacrylonitrile electrospun porous membrane, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide, the vinyl oxide body is polyethylene oxide, and the mass percentage of each component in the quaternary composite system is: rigid framework 10~20%, vinyl oxide body 50~70%, lithium salt 15~25%, and functionalized covalent organic framework filler 0.3~0.9%.

3. The dual-ion regulated composite solid electrolyte according to claim 2, characterized in that, When the molar ratio of the methoxy group to the imidazole cation is 1:1, the lithium-ion transference number is ≥0.73, and the room temperature ionic conductivity is ≥ .

4. The dual-ion regulated composite solid electrolyte according to claim 3, characterized in that, The rigid skeleton has a pore size of 1.0~3.0μm and a porosity of 70~85%.

5. The dual-ion regulated composite solid electrolyte as described in claim 4, characterized in that, The specific surface area of ​​the functionalized covalent organic framework filler is The pore size is concentrated in the range of 3.0~4.0 nm.

6. The dual-ion regulated composite solid electrolyte as described in claim 5, characterized in that, The functionalized covalent organic framework filler is synthesized by a solvothermal method, specifically: a monomer with methoxy and aldehyde groups and an ionic liquid with amino and imidazole groups are dissolved in a mixed solvent of mesitylene and dioxane at a certain molar ratio, and then o-dichlorobenzene, n-butanol and acetic acid are added sequentially. After freezing and sealing, the mixture is statically reacted at 120°C for 3-5 days. After the reaction is completed, the mixture is washed and dried to obtain the filler.

7. The preparation method of a dual-ion regulated composite solid electrolyte as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Dissolve polyethylene oxide and lithium salt in acetonitrile or N,N-dimethylformamide, and stir magnetically until completely dissolved to obtain solution A; Step 2: Add the functionalized covalent organic framework filler to solution A at a mass percentage of 0.3-0.9%, disperse it ultrasonically for 20-60 minutes, and then mechanically stir for 4-8 hours to obtain a uniform slurry B; Step 3: Pour slurry B onto a rigid skeleton, volatilize at 40-60℃ for 4-8 hours, and then vacuum dry at 60-80℃ for 12-24 hours to obtain a dual-ion regulated composite solid electrolyte.

8. The application of the dual-ion regulated composite solid electrolyte as described in any one of claims 1-6 in the preparation of solid-state lithium-ion batteries, characterized in that, The solid-state lithium-ion battery includes a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte is a dual-ion regulated composite solid-state electrolyte.

9. The application as described in claim 8, characterized in that, The room temperature ionic conductivity of the dual-ion regulated composite solid electrolyte is ≥ The lithium-ion transference number is ≥0.

73.

10. The application as described in claim 9, characterized in that, The active material of the positive electrode is lithium iron phosphate or nickel-cobalt-manganese ternary material, and the negative electrode is metallic lithium or graphite.

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