Ionic polymer electrolyte liPSBI, method for preparing the same, and use thereof

Abstract

This invention discloses an ionic polymer electrolyte LiPSBI, its preparation method, and its applications, belonging to the field of lithium-ion battery technology. Using 4,4'-oxybis(benzenesulfonyl chloride), p-methylaminobenzenesulfonic acid, and 4,4'-diaminodiphenyl sulfone as raw materials, this invention designs and synthesizes an aromatic polyamide ionic polymer electrolyte LiPSBI with high lithium-ion exchange capacity. Through structural self-assembly, utilizing the physical incompatibility between rigid LiPSBI and flexible PVDF-HFP, a novel ionic polymer electrolyte membrane NSIPM with high porosity can be formed. The introduction of rigid benzene ring segments provides good thermal and mechanical stability to the polymer electrolyte membrane, while the high polarity of fluorine atoms in the flexible PVDF-HFP enhances lithium-ion movement. The battery based on the NSIPM-EC / DMC electrolyte of this invention achieves a discharge specific capacity of 167.5 mAh g⁻¹ at 0.1C and 1C. ‑1 and 129.6mAh g ‑1 It has a stable and reversible discharge capability.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, specifically relating to an ionic polymer electrolyte LiPSBI, its preparation method, and its application. Background Technology

[0002] Today, lithium-ion batteries have become widely used energy storage and conversion components, and the development of mobile communication devices and new energy electric vehicles relies on the energy provided by battery systems. However, traditional polyolefin separators suffer from poor electrolyte wettability, easy shrinkage under heat, and concentration polarization in small molecule lithium salt electrolytes, which seriously affect the performance and safety of lithium-ion batteries.

[0003] Ionic conductive solid polymer electrolytes have attracted widespread attention due to their thermal stability, chemical stability, and good processability. In particular, SiC-SPEs can effectively suppress lithium dendrite formation and improve battery safety by restricting anion migration. However, most ionic conductive solid polymer electrolytes containing simple functional groups have low room-temperature ionic conductivity, making them difficult to apply in practice. Although adding appropriate amounts of organic solvents (EC, PC, DMC, DEC, etc.) as plasticizers to solid polymer electrolyte systems can yield ionic conductive gel polymer electrolytes with significantly improved ionic conductivity, they still lag behind commercially available dual-ion membrane / electrolyte systems.

[0004] Based on the above reasons, this application is hereby submitted. Summary of the Invention

[0005] Based on the above reasons, and in view of the problems or defects existing in the prior art, the purpose of this invention is to provide an ionic polymer electrolyte LiPSBI, its preparation method and application, to solve or at least partially solve the above-mentioned technical defects existing in the prior art.

[0006] To achieve the first objective of this invention, the technical solution adopted by this invention is as follows:

[0007] A method for preparing an ionic polymeric electrolyte LiPSBI, the method specifically comprising the following steps:

[0008] (1) Synthesis of OX-BMSI

[0009] Weigh p-toluenesulfonyl and potassium hydroxide into a reaction flask according to the ratio, then add deionized water and stir until completely dissolved; adjust the temperature of the resulting solution to 75-85℃, then weigh 4,4'-oxobis(benzenesulfonyl chloride) according to the ratio and slowly add it to the reaction flask in batches; after the addition is complete, adjust the reaction temperature to 90-100℃ and react at a constant temperature for 10-15 hours.

[0010] After the reaction was completed, dilute hydrochloric acid solution was added to the product while it was still hot to adjust the pH of the product to 7; then the product was filtered, the filtrate was collected, and dilute hydrochloric acid solution was added to the filtrate to adjust the pH of the filtrate to 1, resulting in a milky white precipitate. The white precipitate was collected by centrifugation and recrystallized to obtain the di(bis(sulfonylimide)phenyldimethyl precursor OX-BMSI).

[0011] (2) Synthesis of OX-BCSI

[0012] Weigh the OX-BMSI and potassium hydroxide from step (1) according to the ratio, and add them sequentially to a double-necked flask 1 equipped with a water separator. Then add deionized water. After complete dissolution, heat the system to 85-95°C and introduce cooling water. Then slowly add potassium permanganate to the double-necked flask 1 at 85-95°C. After the addition is complete, stir the reaction at a constant temperature for 10-15 hours. After the reaction is complete, cool to room temperature, filter the obtained product, add excess concentrated hydrochloric acid to the filtrate, let it stand, filter again to obtain the crude product, recrystallize, dry, and obtain the di(bis(sulfonylimide)benzenediacarboxylic acid precursor OX-BCSI.

[0013] (3) Synthesis of LiPSBI

[0014] Weigh 4,4'-diaminodiphenyl sulfone and OX-BCSI according to the specified ratio, and place them sequentially into a double-necked flask 2 equipped with a water separator. Then, add anhydrous lithium chloride according to the specified ratio, purge with cooling water, and fill the reaction system with inert gas. Then, under an inert atmosphere, sequentially inject anhydrous nitrogen-methylpyrrolidone (NMP), pyridine (Py), and triphenyl phosphite (TPP) into the double-necked flask 2 and stir to dissolve at room temperature. Next, heat the reaction system to 95-105℃ and react at a constant temperature for 20-30 hours.

[0015] After the reaction is complete, cool to room temperature and slowly pour the obtained product into an excess of anhydrous methanol while stirring the methanol solution until the white solid is completely precipitated. Filter, remove the filtrate, retain the filter cake, wash, and obtain the white product. Dry; take out the dried product, fully lithiate it, filter, wash the obtained filter cake, and dry to obtain the ionic polymer electrolyte LiPSBI.

[0016] Furthermore, in step (1) of the above technical solution, the molar ratio of p-toluenesulfonamide to potassium hydroxide is 1:1.

[0017] Furthermore, in step (1) of the above technical solution, the molar ratio of p-methylbenzenesulfonamide to 4,4'-oxobis(benzenesulfonyl chloride) is 4:1.

[0018] Furthermore, in step (1) of the above technical solution, the amount of deionized water is not specifically limited, as long as it can achieve uniform dissolution of p-toluenesulfonamide and potassium hydroxide. In a preferred embodiment of the present invention, the ratio of p-toluenesulfonamide to deionized water is 0.048 mol: 15 mL.

[0019] Furthermore, in step (1) of the above technical solution, the reaction temperature is preferably 95°C and the reaction time is preferably 12h.

[0020] Furthermore, in step (2) of the above technical solution, the molar ratio of OX-BMSI to potassium hydroxide is 1:2.

[0021] Furthermore, in step (2) of the above technical solution, the amount of deionized water used is not specifically limited, as long as it can achieve uniform dissolution of OX-BMSI and potassium hydroxide. In a preferred embodiment of the present invention, the ratio of OX-BMSI to deionized water is 0.006 mol: 200 mL.

[0022] Furthermore, in step (2) of the above technical solution, the molar ratio of OX-BMSI to potassium permanganate is 2:1.

[0023] Furthermore, in step (2) of the above technical solution, the potassium permanganate is added at a time not exceeding 2 hours.

[0024] Furthermore, in step (2) of the above technical solution, the settling time is 20-40 minutes.

[0025] Furthermore, in step (3) of the above technical solution, the molar ratio of 4,4'-diaminodiphenyl sulfone to OX-BCSI is 1:1.

[0026] Furthermore, in step (3) of the above technical solution, the molar ratio of anhydrous lithium chloride to OX-BCSI is 4:1.

[0027] Furthermore, in step (3) of the above technical solution, the inert gas is preferably pure argon.

[0028] Furthermore, in step (3) of the above technical solution, the volume ratio of NMP, Py and TPP is 20:15:(5-10).

[0029] Furthermore, in step (3) of the above technical solution, the ratio of OX-BCSI to NMP is (1-5) mmol: 20 mL.

[0030] Furthermore, in step (3) of the above technical solution, the reaction temperature is preferably 100℃ and the reaction time is preferably 24h.

[0031] A second objective of this invention is to provide an ionic polymer electrolyte, LiPSBI, prepared using the method described above.

[0032] A third objective of this invention is to provide the application of the ionic polymer electrolyte LiPSBI prepared by the method described above in the preparation of a novel ionic polymer electrolyte porous membrane NSIPM.

[0033] A novel method for preparing an ionic polymer electrolyte porous membrane (NSIPM) includes the following steps:

[0034] The ionic conductive polymer electrolyte LiPSBI and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) were dissolved in dimethyl sulfoxide (DMSO) in sequence according to the formula to form a homogeneous solution; then the resulting solution was uniformly coated on the surface of a glass plate and dried to obtain the novel ionic polymer electrolyte porous membrane NSIPM.

[0035] Furthermore, in the above technical solution, the mass ratio of the ionic conductive polymer electrolyte LiPSBI to PVDF-HFP is 1:1.

[0036] A fourth objective of this invention is to provide a novel ionic polymer electrolyte porous membrane (NSIPM) prepared by the method described above.

[0037] The fifth objective of this invention is to provide the application of the novel ionic polymer electrolyte porous membrane NSIPM described above in lithium-ion batteries.

[0038] A lithium-ion battery includes a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the separator is the novel ionic polymer electrolyte porous membrane NSIPM described above.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) This invention uses 4,4'-oxobis(benzenesulfonyl chloride), p-methylaminobenzenesulfonic acid, and 4,4'-diaminodiphenyl sulfone as raw materials to design and synthesize an aromatic polyamide ionic polymer electrolyte LiPSBI with high lithium-ion exchange capacity. By utilizing the structural self-assembly method and the physical incompatibility between rigid LiPSBI and flexible PVDF-HFP, a novel ionic polymer electrolyte membrane NSIPM with high porosity can be formed. The introduction of rigid benzene ring segments provides good thermal and mechanical stability to the polymer electrolyte membrane, while the high polarity of fluorine atoms in the flexible PVDF-HFP enhances lithium-ion mobility.

[0041] (2) The battery based on NSIPM-EC / DMC electrolyte of this invention can achieve a discharge specific capacity of 167.5 mAh g at 0.1C and 1C. -1 and 129.6mAh g -1 It exhibits stable and reversible discharge capability, with a capacity higher than that of SIPM-EC / DMC electrolyte (145.1 mAh g). -1 and 115.9mAh g -1 Furthermore, during battery cycle testing at 0.2C, the initial discharge specific capacity of the battery based on the NSIPM-EC / DMC electrolyte was 148.4 mAh g⁻¹. -1 This is significantly higher than the 124.1 mAh g of the SIPM-EC / DMC electrolyte. -1 After 450 charge-discharge cycles, the former still maintains 116.3 mAh g. -1 The discharge capacity and coulombic efficiency of the first-generation discharge capacity were 98.9%, with only 21.6% of the initial capacity decaying, averaging only 0.048% decay per cycle. In contrast, the latter not only had a lower discharge capacity but also exhibited poor cycle stability. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a synthesis route diagram of OX-BMSI and OX-BCSI in Example 1;

[0044] Figure 2 This is a route diagram for the synthesis of LiPSBI from OX-BCSI in Example 1;

[0045] Figure 3 This is a schematic diagram of the synthesis of LiPSI in Comparative Example 1;

[0046] Figure 4 A schematic diagram of the preparation process of the novel ionic polymer electrolyte porous membrane NSIPM in Application Example 1;

[0047] Figure 5 1H NMR spectra: (a) OX-BMSI; (b) OX-BCSI; (c) LiPSI; (d) LiPSI;

[0048] Figure 6 Infrared spectrum of LiPSBI prepared in Example 1;

[0049] Figure 7 DFT-optimized geometry: (a) LiPSI; (b) LiPSBI; light gray, purple, gray, dark blue, red, and yellow represent H, Li, C, N, O, F, and S atoms, respectively.

[0050] Figure 8 (ae) SEM images of NSIPM at different magnifications and corresponding EDS element mapping diagrams (a)×500; (b)×1000; (c)×9000; (d)×2000; (e)×7000; (f) EDS mapping diagram of N element; (gj) Contact angle between the membrane and the electrolyte EC / DMC (1:1, v / v); (g) NSIPM; (h) SIPM; (i) PP membrane; (j) PVDF-HFP membrane;

[0051] Figure 9 Thermal stability of materials and diaphragms: (a) TG curve; (b) DSC curve; (c) Thermal shrinkage at different temperatures;

[0052] Figure 10 Mechanical property test diagrams: (a) Unfolding, twisting, bending and folding diagrams of NSIPM; (b) Tensile diagram of NSIPM; (c) Tensile diagram of SIPM; (d) Tensile diagram of PP film;

[0053] Figure 11 (ac) Time-current curves of the insertion impedance plots (a) PP-1M LiPF6-EC / DMC electrolyte; (b) NSIPM-1M LiPF6-EC / DMC electrolyte; (c) NSIPM-EC / DMC electrolyte; (d) Long-term galvanocurrent cycling test of symmetrical lithium battery; (e) Linear sweep voltammogram of NSIPM-EC / DMC electrolyte; (fh) Galvanocurrent cycling plots of the corresponding symmetrical lithium battery for the electrolyte system in the 250-255h interval; (f) PP-1M LiPF6-EC / DMC electrolyte; (g) NSIPM-1M LiPF6-EC / DMC electrolyte; (h) NSIPM-EC / DMC electrolyte;

[0054] Figure 12 Lithium sheet surface morphology (ac) Optical image of the original lithium sheet, SEM plane, cross section; (df) Optical image of the lithium sheet after 320h galvanic cycling with PP-1MLiPF6-EC / DMC electrolyte, SEM plane, cross section; (gi) Optical image of the lithium sheet after 1600h galvanic cycling with NSIPM-1MLiPF6-EC / DMC electrolyte, SEM plane, cross section; (jl) Optical image of the lithium sheet after 1600h galvanic cycling with NSIPM-EC / DMC electrolyte, SEM plane, cross section;

[0055] Figure 13 Comparison of electrochemical performance of NSIPM, SIPM and PP membranes in different electrolysis systems: (a) Impedance diagram at room temperature; (b) Ionic conductivity; (c) Rate performance of LiFePO4|Li battery at room temperature; (d) Charge-discharge curves of NSIPM-EC / DMC electrolyte at different rates at room temperature; (e) Cycling performance of LiFePO4|Li battery at 0.2C at room temperature; (f) Cycling performance of LiFePO4|Li battery at 1C at room temperature. Detailed Implementation

[0056] Applying the design of macromolecules with multiple functional groups to polymer matrices is considered a strategy to fundamentally improve the performance of ionic conductive polymer electrolytes. In recent years, macromolecule design based on single lithium-ion conductive groups has been employed, including copolymerization, network construction, and grafting. The bis(sulfonyl)imide group (-SO2N) possesses hyperdelocalized properties. － SO2- is widely used in the design of efficient and safe ionic conductive polymer electrolytes. Bouchet and his colleagues prepared a multifunctional ionic polymer electrolyte based on a poly(styrene)bis(sulfonyl)imide lithium anionic block copolymer, P(STFSILi)-PEO-P(STFSILi), containing polystyrene segments. A solid polymer electrolyte membrane was obtained via a simple solution casting method, exhibiting a lithium-ion transference number greater than 0.85. At 60°C, its ionic conductivity reached 1.3 × 10⁻⁶. -5 S cm -1 This is higher than most solid polymer electrolytes, which is not only due to the ability of EO monomers to provide Li + It provides a large number of lone pairs of electrons that can form complexes, and also depends on Li + It exhibits a weak interaction with the polybis(sulfonamide) anion. Furthermore, due to the excellent styrene segment providing good skeletal support, it displays superior mechanical properties.

[0057] Based on the above research, this invention uses 4,4'-oxobis(benzenesulfonyl chloride), p-methylaminobenzenesulfonic acid, and 4,4'-diaminodiphenyl sulfone as raw materials to design and synthesize an aromatic polyamide ionic polymer electrolyte, LiPSBI, with high lithium-ion exchange capacity. By utilizing the structural self-assembly method and the physical incompatibility between rigid LiPSBI and flexible PVDF-HFP, a novel ionic polymer electrolyte membrane, NSIPM, with high porosity can be formed. The introduction of rigid benzene ring segments provides good thermal and mechanical stability to the polymer electrolyte membrane, while the high polarity of fluorine atoms in flexible PVDF-HFP enhances lithium-ion mobility. To objectively evaluate the effect of the designed ionic polymer electrolyte on improving ionic conductivity and battery performance, another aromatic polyamide ionic polymer electrolyte, LiPSI, with low lithium disulfonylimide carrier content, was used as a control, and the membrane, SIPM, was prepared using the same method.

[0058] The present invention will be further described in detail below through implementation examples. These implementation examples are carried out based on the technology of the present invention. Detailed implementation methods and specific operating procedures are provided to illustrate the inventiveness of the present invention, but the scope of protection of the present invention is not limited to the following implementation examples.

[0059] To better understand the invention and not to limit its scope, all figures indicating amounts, percentages, and other numerical values ​​used in this application should, in all cases, be understood to be modified by the word "approximately." Therefore, unless otherwise stated, the numerical parameters listed in the specification are approximate values ​​and may vary depending on the desired properties being sought. Each numerical parameter should at least be considered as obtained based on reported significant figures and through conventional rounding methods.

[0060] The equipment and raw materials used in this invention are all commercially available or commonly used in the field. Unless otherwise specified, the methods in the following embodiments are conventional methods in the field.

[0061] Example 1

[0062] The method for synthesizing an ionic polymer electrolyte LiPSBI according to this embodiment includes the following steps:

[0063] (1) Synthesis of OX-BMSI:

[0064] Weigh 8.22 g (0.048 mol) of p-toluenesulfonamide and 2.69 g (0.048 mol) of potassium hydroxide granules into a 25 mL double-necked flask, add 15 mL of deionized water, and stir until completely dissolved. Adjust the solution temperature to 80 °C. Weigh 4.41 g (0.012 mol) of 4,4'-oxobis(benzenesulfonyl chloride) and slowly add it in batches to the reaction flask using a spatula. After the addition is complete, adjust the reaction temperature to 95 °C and allow it to react completely for 12 h.

[0065] After the reaction was complete, the solution was transferred to a 50 mL beaker while still hot. 0.1 mol / L hydrochloric acid solution was added to adjust the pH of the reaction solution to 7, resulting in a white precipitate. The filtrate was collected after filtration, and hydrochloric acid solution was added again to adjust the pH to 1, yielding a milky white precipitate. The white precipitate was collected by centrifugation and recrystallized to obtain the product, di(bis(sulfonylimide)phenyldimethyl) precursor OX-BMSI. After drying, the product weighed 6.624 g, with a yield of 86.7%.

[0066] (2) Synthesis of OX-BCSI

[0067] Weigh 3.816 g (0.006 mol) of the dried OX-BMSI from step (1) and 0.672 g (0.012 mol) of potassium hydroxide, and add them sequentially to a 500 mL double-necked flask equipped with a Dean-Stark separator. Add 200 mL of deionized water to completely dissolve the precipitate, and then pass condenser water through the flask. Then weigh 4.74 g (0.03 mol) of potassium permanganate and slowly add the solid potassium permanganate particles to the above solution at 90 °C (within 2 h). At this point, the solution is purple-red. Stir the reaction for 12 h. After the reaction is complete, stop heating and allow it to cool to room temperature. Filter the solution to obtain a colorless and transparent solution. Add excess concentrated hydrochloric acid to the filtrate, and a large amount of white precipitate will form. After standing for 30 min, filter the solution to obtain the crude product. Finally, recrystallize the crude product in deionized water, and after drying, obtain 3.587 g of the target product, the di(bis(sulfonylimide)benzenediacarboxylic acid) precursor OX-BCSI, with a yield of 85.8%.

[0068] (3) Synthesis of LiPSBI

[0069] 0.86 g (3.45 mmol) of 4,4'-diaminodiphenyl sulfone and 2.4 g (3.45 mmol) of bis(bissulfimide)benzenedicarboxylic acid precursor (OX-BCSI) were placed sequentially into a 100 mL double-necked flask equipped with a Dean-Stark water separator. Then, 0.584 g (13.8 mmol) of anhydrous lithium chloride was added. The apparatus was assembled, and cooling water was introduced to fill the apparatus with pure argon gas. Using a disposable syringe, 20 mL of NMP, 15 mL of LPy, and 5.2 mL of TPP were added sequentially through a rubber stopper to the double-necked flask, and the solutions were stirred and dissolved at room temperature. The mixture was then heated to 100 °C and reacted for 24 h. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was slowly poured into an excess of anhydrous methanol while stirring the methanol solution with a glass rod until a white solid completely precipitated. The mixture was filtered, the filtrate was removed, and the filter cake was retained. The filter cake was then washed three times with methanol and deionized water to obtain a white product. The product was dried in an 80℃ forced-air oven for 10 hours, and then dried in a 100℃ vacuum oven for 24 hours. After removing the sample, it was lithiated twice with 0.165 g (6.9 mmol) anhydrous LiOH in 100 mL of methanol solution, 12 hours each time, to ensure complete lithiation. After complete lithiation, the sample was filtered, and the filter cake was washed twice with anhydrous methanol and dried to obtain the target product, the ionic polymer electrolyte LiPSBI, with a mass of 2.66 g and a yield of 81.6%. Figure 2 This is a schematic diagram illustrating the synthesis of the final product, LiPSBI.

[0070] Comparative Example 1

[0071] The synthesis method of the ionic polymer electrolyte LiPSI in this comparative example is similar to the synthesis method of LiPSBI in Example 1, and also consists of three steps, as follows:

[0072] (1) Synthesis of MBSI

[0073] Weigh 4.281 g (0.025 mol) of p-toluenesulfonamide and 1.4 g (0.025 mol) of potassium hydroxide granules into a 25 mL double-necked flask, add 15 mL of deionized water, and stir until completely dissolved. Adjust the solution temperature to 80 °C, and slowly add 4.766 g (0.025 mol) of p-toluenesulfonyl chloride in batches to the reaction flask using a spatula. After the addition is complete, adjust the reaction temperature to 95 °C and allow it to react completely for 12 h. After the reaction is complete, transfer the hot solution to a 50 mL beaker, add 0.1 mol / L hydrochloric acid solution to adjust the pH of the reaction solution to 7, and a white precipitate will appear. After filtration, collect the filtrate, continue to add hydrochloric acid solution to adjust the pH to 1, and obtain a white precipitate. Filter, retain the filter cake, recrystallize to obtain the first step product, 4,4-dimethylbis(benzenesulfonyl)imide (MBSI), and dry for later use.

[0074] (2) Synthesis of CBSI

[0075] Weigh 4.875 g (0.015 mol) of MBSI dried in step (1) and 0.84 g (0.015 mol) of potassium hydroxide, and add them sequentially to a 500 mL double-necked flask. Add 200 mL of deionized water to completely dissolve them, and then pass condenser water through the flask. Then weigh 11.85 g (0.075 mol) of potassium permanganate and slowly add the solid potassium permanganate particles to the above solution at 90 °C (within 2 h). At this time, the solution is purple-red. Stir the reaction for 12 h. After the reaction is complete, stop heating and let it cool to room temperature. Filter to obtain a colorless and transparent solution. Add excess concentrated hydrochloric acid to the filtrate, and a large amount of white precipitate will precipitate. After standing for 30 min, filter to obtain the crude product. Finally, recrystallize in deionized water to obtain the precursor 4,4-dicarboxylic bis(benzenesulfonyl)imide CBSI, and dry it for later use.

[0076] (3) Synthesis of LiPSI

[0077] 1.61 g (6.49 mmol) of 4,4'-diaminodiphenyl sulfone and 2.5 g (6.49 mmol) of 4,4-dicarboxylic acid bis(benzenesulfonyl)imide precursor (CBSI) were placed sequentially into a 100 mL double-necked flask, followed by 1.11 g (26.0 mmol) of anhydrous lithium chloride. The apparatus was assembled, and cooling water was introduced to fill the flask with pure argon gas. 20 mL of NMP, 15 mL of Py, and 5.2 mL of TPP were added sequentially through a rubber stopper to the double-necked flask using a disposable syringe, and the solutions were stirred and dissolved at room temperature. The mixture was then heated to 100 °C and reacted for 24 h. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was slowly poured into an excess of anhydrous methanol while stirring the methanol solution with a glass rod until a white solid completely precipitated. The mixture was filtered, the filtrate was removed, and the filter cake was retained. The filter cake was then washed three times with methanol and deionized water to obtain a white product. The product was dried in an 80℃ forced-air oven for 10 hours, and then dried in a 100℃ vacuum oven for 24 hours. After removing the sample, it was lithiated twice with 0.155 g (6.49 mmol) of anhydrous LiOH in 100 mL of methanol solution, 12 hours each time, to ensure complete lithiation. After complete lithiation, the sample was filtered, and the filter cake was washed twice with anhydrous methanol and dried to obtain the target product, the ionic polymer electrolyte LiPSI. Figure 3 This is a schematic diagram illustrating the synthesis of the final product, LiPSI.

[0078] Application Example 1

[0079] This application example describes a method for preparing a novel ionic polymer electrolyte porous membrane (NSIPM), comprising the following steps:

[0080] Figure 4The preparation process of NSIPM is demonstrated. The ionic conductive polymer electrolyte LiPSBI prepared in Example 1 and an equal mass of PVDF-HFP were dissolved in DMSO at 80°C and stirred for 12 hours to form a homogeneous solution with a mass fraction of 10%. A flat glass plate was placed on a heating plate, and the solution was evenly coated onto the glass plate. The heating plate temperature was adjusted to 80°C and left for 10 hours. After the solvent had completely evaporated, the novel ionic polymer electrolyte porous membrane NSIPM with a thickness of approximately 20 micrometers was obtained and dried for later use.

[0081] Comparative Application Example 1

[0082] This comparative application example describes a method for preparing an ionic polymer electrolyte porous membrane (SIPM), comprising the following steps:

[0083] The ionic conductive polymer electrolyte LiPSI prepared in Comparative Example 1 and an equal mass of PVDF-HFP were dissolved in DMSO by heating. After stirring for 12 h, a homogeneous solution with a mass fraction of 10% was formed. A flat glass plate was placed on a heating plate, and the solution was evenly coated on the glass plate. The temperature of the heating plate was adjusted to 80 °C, and the mixture was left to stand for 10 h. After the solvent had completely evaporated, an ionic polymer electrolyte porous membrane SIPM with a thickness of approximately 20 micrometers was obtained and dried for later use.

[0084] Structural characterization of ionic polymers

[0085] Nuclear magnetic resonance spectroscopy (NMR) is frequently used for the structural analysis of organic polymers and is an important method for molecular structure characterization. Based on the type of atom being measured, it is classified into: proton NMR (hydrogen nucleus), carbon NMR, boron NMR, fluorine NMR, phosphorus NMR, and nitrogen NMR, etc. In this invention, proton NMR spectroscopy is used to analyze the structure of intermediates and ionic polymers. The test results are as follows: Figure 5 As shown. Among them, Figure 5 a represents the characterization results of the intermediate OX-BMSI. The ratio of the five peak areas is 1.54:1:1.13:1:0.95, which basically corresponds to the five different types of hydrogen (H) in the molecular structure. A H B H C H D H E The ratio is 3:2:2:2:2. The doublet at chemical shifts of 2.30-2.40 ppm belongs to the H group on the benzyl group. A The doublet at 7.15-7.25 ppm belongs to H on the benzene ring. B The peak at 7.64-7.73 ppm belongs to the H on the benzene ring. C The doublet at 7.51-7.57 ppm belongs to the H on the benzene ring. DThe doublet at 6.97-7.03 ppm belongs to H on the benzene ring. E .

[0086] Figure 5 Figure b marks the peaks corresponding to different types of hydrogen in the intermediate OX-BCSI structure. The area ratio of the four doublets is 1.01:1.02:0.98:1, which basically corresponds to the four types of hydrogen. A H B H C H D The proportion it occupies in the molecular structure. The doublet at chemical shifts of 7.88-7.96 ppm belongs to H. A The double peak at 7.70-7.76 ppm belongs to H. B The double peak at 7.61-7.68 ppm belongs to H. C The double peak at 6.89-6.96 ppm belongs to H D Additionally, the broad peak at chemical shift 3.65 should belong to the active hydrogen atom on the carboxyl group. Figure 4 Analysis shows that the disappearance of the methyl peak at 2.30-2.40 ppm proves that the methyl group was completely oxidized to a carboxyl group, indicating the successful synthesis of the precursor OX-BCSI. Similarly, the synthesis of intermediates MBSI and CBSI is also verified.

[0087] Figure 5 c is the 1H NMR spectrum of the ionic polymer LiPSBI. It contains seven different types of hydrogen atoms (H₂). A H B +H C H D H E H F H G The area ratio is 1:1.94:0.81:1.11:1.03:0.46, which basically conforms to the proportion of various hydrogen atoms in different chemical environments in the target product structure. The six doublets with chemical shifts of 6.95-8.10 ppm should belong to H atoms on the benzene ring. A H B H C H D H E H F The amide peak H at 10.75 ppm G The appearance of this product proves that the target product LiPSBI was successfully synthesized.

[0088] Similarly, analysis can be performed. Figure 5 The five hydrogen atoms marked in d A H B H C H D HE The corresponding peak positions, and the appearance of the amide peak at 10.75 ppm, also prove that LiPSI was successfully synthesized.

[0089] Infrared absorption spectroscopy is generated by the vibrational and rotational motions of molecules. Due to differences in elemental composition and structure, each molecule has a unique spectrum. Therefore, Fourier transform infrared spectroscopy is often used for qualitative molecular analysis. LiPSBI's Fourier transform infrared spectroscopy (FT-IR) is shown below. Figure 6 As shown. 3485cm -1 The peak at that location is due to Li + The presence of ions and their strong polarity cause the -OH group to stretch and contract upon absorbing moisture from the air. 3392 cm⁻¹ -1 The peaks at these locations can be designated as absorption peaks of free -NH2. (Campi: 3102, 1673, 1591, 1529, 1262, 1153 cm⁻¹) -1 The peaks at 1107 and 1083 cm⁻¹ represent CH stretching, C=O stretching, C=C benzene ring skeleton stretching, NH bending, CN stretching, and COC stretching, respectively. -1 The peaks at these locations belong to O=S=O symmetric stretching and antisymmetric stretching, respectively.

[0090] Gel permeation chromatography (GPC) can not only identify and separate small molecules, but also measure the relative molecular mass of polymers. To further determine the occurrence of polymerization and the degree of polymerization of the product, gel permeation chromatography was performed on the sample. The results showed that the number-average molecular weight (Mn) of LiPSBI was... n The weight-average molecular weight (M) is 33579. W The number-average molecular weight (Mn) of LiPSI is 70006, and the dispersion index (PDI) is 2.08. n The weight-average molecular weight (M) is 11396. W The coefficient of variation (PDI) was 1.27, with a value of 14469. These tests fully demonstrate the successful synthesis of the ionic polymer electrolytes LiPSBI and LiPSI.

[0091] Density functional theory (DFT) calculations, by studying molecular structure, bond lengths, and vibrations, can further explore the mechanisms behind material properties, serving as a supplement to experiments. Therefore, to demonstrate the role of the structural design in improving the performance of ionic polymer electrolytes, DFT calculations were used to determine the dissociation energies of the two polymer salts. Figure 7 It refers to the optimized geometry of the two molecules during DFT calculations.

[0092] The lithium-ion dissociation energies of LiPSBI and LiPSI were obtained by DFT calculation. As shown in Table 1, the first-order dissociation energy of LiPSBI in one structural unit is 152.41 kcal / mol, which is lower than that of LiPSI (160.54 kcal / mol). This proves that some Li in the LiPSBI structure... + Lithium ions more readily dissociate from the polymer, becoming free lithium ions capable of electron transport. However, due to the enhanced electrostatic attraction of the polymer anion in LiPSBI to the remaining lithium ions after primary dissociation, the secondary dissociation energy increases to 274.30 kcal / mol. Calculations show that the mass fraction of lithium in the LiPSBI polymer structural unit increases from 1.16% in LiPSI to 1.52%, which will benefit the increase of Li- ions that can act as electron conduction mediators in ionic polymer electrolytes. + This increases the content of [resources], thereby further improving battery performance.

[0093] Table 1. Polymer dissociation energy and lithium content values ​​obtained by DFT calculation.

[0094]

[0095] Morphology and physical property characterization of ionic polymer electrolyte membranes

[0096] To analyze and verify the structure-property relationship between the microstructure of the ionic polymer electrolyte membrane and battery performance, the surface morphology of the NSIPM was characterized using scanning electron microscopy (SEM). The results are as follows: Figure 8 As shown in the SEM images, uniformly dispersed, interconnected pores can be observed on both the surface and cross-section of NSIPM. Figure 8 This is due to the physical incompatibility between the aromatic polyamide backbone and the flexible PVDF-HFP. The porous structure plays an important role in improving liquid absorption and battery performance. The N elemental mapping image in X-ray energy dispersive spectroscopy (EDS) shows that the polymer is uniformly distributed in the separator without agglomeration, and also indicates a uniform distribution of lithium in the NSIPM, which is beneficial for achieving uniform lithium ion plating / stripping and suppressing lithium dendrite formation. Figure 8 f).

[0097] Rapid wetting between polymer electrolytes and electrolyte solutions is highly beneficial for enhancing battery performance and reducing battery assembly time. Here, wetting speed is evaluated by measuring contact angle. Images obtained by dropping a mixed organic solvent EC / DMC (1:1, v / v) onto NSIPM, SIPM, PP, and PVDF-HFP membranes are shown below. Figure 8In gj, the wetting speed between PP film and PVDF-HFP film and electrolyte is very slow, with contact angles of 55.8° and 65.6° at 1s, and 44.7° and 50.6° at 120s, respectively. This is due to the hydrophobicity and low surface energy of the nonpolar olefin skeleton itself. In contrast, NSIPM and SIPM prepared by the same method have good wettability, both superior to commercial PP film and PVDF-HFP film. Specifically, NSIPM's contact angles at 1s and 120s are 48.6° and 30.3°, respectively, thanks to the polar bis(sulfonyl)imide groups and the high porosity generated during structural self-assembly. SIPM's contact angles at 1s and 120s are 50.1° and 35.5°, respectively, showing slightly worse wettability than NSIPM. This may be because the LiPSBI ionic polymer structure contains a small amount of polar aromatic ether, which improves the compatibility between the material and the electrolyte, while the LiPSI molecular structure does not contain this group.

[0098] Table 2 Physical properties of the diaphragm

[0099]

[0100] Electrolytes with high dielectric constants can promote the dissociation of lithium ions; therefore, the liquid absorption rate and porosity of the membrane are key to improving ionic conductivity. In this invention, the liquid absorption rate and porosity of the membrane were tested using EC / DMC (1:1, v / v) organic solvent and n-butanol solution, respectively, and the specific values ​​were calculated and listed in Table 2. The results show that the liquid absorption rate of the ionic polymer electrolyte porous membrane prepared by the structural self-assembly method is as high as 181%, far exceeding the 67% and 21.2% of PP membranes and PVDF-HFP membranes, respectively. The porosity of NSIPM is 41.4%, nearly twice that of the PP membrane and six times that of PVDF-HFP.

[0101] The thermal stability of materials is crucial for ensuring the safe operation of batteries. In this study, thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were used to test the high-temperature resistance of the materials. Thermogravimetric analysis was used to analyze the thermal stability of the materials under a nitrogen atmosphere, with a heating rate of 10℃ / min. -1 The test temperature range is 30 to 800℃. Figure 9 This paper shows the mass variation of LiPSBI powder, NSIPM, SIPM, PP film, and PVDF-HFP film with temperature. The results indicate that all five exhibit thermal stability up to 400℃, and that LiPSBI powder, NSIPM, and SIPM containing aromatic polyamide materials show lower weight loss after reaching their thermal decomposition temperature. Figure 9The DSC curves of the PP membrane and PVDF-HFP membrane in section b show obvious endothermic peaks at 153.5℃ and 154.9℃, respectively, corresponding to their melting points, while the absorption peak of NSIPM is relatively weaker. This indicates that the novel ionic polymer electrolyte porous membrane prepared has higher thermal stability.

[0102] The dimensional stability of the diaphragm at high temperatures was further tested by observing its thermal shrinkage at different temperatures on a heating plate. Figure 9 As shown in Figure c, PP film and PVDF-HFP film exhibited severe thermal shrinkage at 140℃ and 170℃, respectively, while NSIPM still showed good thermal dimensional stability at temperatures up to 320℃. This indicates that NSIPM will overcome the safety hazards of lithium batteries operating over a wide range of temperatures.

[0103] The good flexibility and mechanical properties of polymer electrolytes are crucial for the long-term operation of batteries. The superior mechanical properties of the separator not only ensure stable battery operation, but its high mechanical strength also physically inhibits the growth of lithium dendrites. Mechanical tensile strength testing was conducted using a mechanical tensile strength tester. The separator was cut into a 1cm × 4cm shape and tested using a tensile testing machine at 25mm min. -1 Tensile strength tests were conducted at various strain rates. The mechanical properties of NSIPM are as follows: Figure 10 As shown in Figure a, the diaphragm can withstand a certain degree of torsion, bending, and folding without significant damage. Furthermore, a mechanical tensile test was used to compare the mechanical properties of the diaphragm. Figure 10 The test results shown by bd indicate that NSIPM achieved a tensile strength of 20 MPa, which is superior to the 14 MPa of SIPM and the 10 MPa of commercial PP film. This is because the benzene ring chemical structure inside the fully aromatic polyamide makes the polymer molecular chain less prone to breakage, resulting in high mechanical strength.

[0104] Lithium-ion transference number and lithium stripping / deposition stability test

[0105] For ease of research, the inventors classified the electrolyte / membrane system into four types: PP-1M LiPF6-EC / DMC (1:1, v / v), NSIPM-1M LiPF6-EC / DMC (1:1, v / v), NSIPM-EC / DMC (1:1, v / v), and SIPM-EC / DMC (1:1, v / v). Impedance testing was performed using an electrochemical impedance spectroscopy (EIS) instrument, primarily to collect feedback information by observing the influence of voltage signals at different frequencies on the system. The EIS testing of this invention was conducted on a VMP3 electrochemical workstation, assembling a LiFePO4|Li half-cell, with a scanning frequency range of 100 kHz to 10 mHz. The preparation process of the LiFePO4 positive electrode is as follows: a certain amount of active material (LiFePO4) in a mass ratio of 7:2:1, acetylene black (AB) conductive additive, and PVDF binder were dissolved in a calculated amount of N-methylpyrrolidone (NMP) to form a slurry, which was then cast onto aluminum foil using a coating machine. Subsequently, the coated aluminum foil was dried in a forced-air oven at 60°C for 12 hours, then cut into 15nm discs for use as the positive electrode of the button cell, and transferred to a vacuum oven at 80°C for overnight drying. Linear sweep voltammetry is commonly used to study the electrochemical performance of batteries. A triangular wave voltage is used to scan between the working electrode and the auxiliary electrode, recording the redox reactions occurring within the corresponding potential range to obtain voltage-current curves, thereby determining information such as the electrolyte boundary potential and the reversibility of electrode reactions. This experiment was conducted on a Vmp3 electrochemical workstation. The stainless steel sheet was labeled SS, and an SS|film|Li battery was assembled. The linear sweep voltammetry test conditions were: a scan rate of 5 mV / s. -1 The starting point is -1V, the ending potential is 5V / 6V, and the data recording time interval is 0.0002s.

[0106] The transference number of lithium ions in different electrolyte systems was measured using the steady-state current method. The impedance spectra of DC polarization and the time-varying response are shown below. Figure 11 As shown in Figure ac, detailed results are summarized in Table 3. The Li in the commercially available PP-1MLiPF6-EC / DMC electrolyte system... + The migration number was only 0.31, while the system using NSIPM-1MLiPF6-EC / DMC gel electrolyte had a Li migration number of only 0.31. + The migration number increased to 0.49. More importantly, in the NSIPM-EC / DMC gel electrolyte system without the addition of commercially available small-molecule lithium salts, the migration number increased because the anions were anchored to the polymer chains. Li + With a value as high as 0.87, it conforms to the basic characteristics of ion-conductive polymer electrolytes.

[0107] Table 3. Lithium-ion transference number test results

[0108]

[0109] The effects of lithium-ion transference number on peeling / plating performance and lithium dendrite growth on the lithium metal anode were investigated through electrolytic stripping / plating cycle tests. Figure 11 As shown in d, when the current density is 2.5 mA / cm² -2 At that time, the gel electrolyte system using NSIPM has better peeling / deposition stability and can be stably cycled for 1600h after an activation phase, which is far superior to the 320h performance of the commercial PP-1M LiPF6-EC / DMC electrolyte system.

[0110] At the same time, by Figure 11 (fh) It can be observed more clearly and intuitively that, compared with the severe burrs in the commercial PP-1MLiPF6-EC / DMC electrolyte system, the gel electrolyte system using NSIPM exhibits a fairly stable and smaller polarization voltage during operation at 250-255h. This may be due to the following reasons: (1) t Li + The significant improvement effectively reduced the concentration polarization of ions inside the battery; (2) The polymer electrolyte LiPSBI contains ether bonds and bis(sulfonyl)imide groups that are compatible with organic electrolytes; (3) NSIPM containing an aromatic polyamide skeleton has good mechanical properties and can inhibit the growth of lithium dendrites.

[0111] The electrochemical window can intuitively measure the electrochemical stability of an electrolyte. This invention uses linear sweep voltammetry (LSV) to measure the electrochemical stability window of polymer electrolytes. The test results are as follows: Figure 11 As shown in Figure e, the redox current remains almost constant from 0 to 4.45 V, but increases sharply after 4.45 V, indicating that the polymer electrolyte is gradually oxidized starting from 4.45 V. Therefore, the electrochemical window of NSIPM is 4.45 V (vs. Li). + / Li) can support the normal operation of the battery.

[0112] The surface morphology of lithium metal in a lithium-symmetric battery after constant current cycling was examined to verify the inhibitory effect of the NSIPM-EC / DMC electrolyte on lithium dendrite growth during long-term electroplating / stripping. The microstructure of the separator was characterized using field emission scanning electron microscopy (FET), with a gold sputtering time of 60 s. Prior to testing, the separator was vacuum-dried at 80 °C for 24 h. Figure 12 As shown in the image, the original lithium sheet's optical photograph and SEM image both show a smooth and flat surface morphology, while the lithium sheet that underwent 320 hours of constant current cycling in PP-1M LiPF6-EC / DMC electrolyte had a rather rough surface with large dendrites. Figure 12 df). For example Figure 12 As shown in Figure gi, after 1600 h of cycling, the lithium sheet in the NSIPM-1MLiPF6-EC / DMC electrolyte still retains a certain metallic luster, and the SEM images show a significant reduction in dead lithium accumulation. These results indicate that the NSIPM-1MLiPF6-EC / DMC electrolyte, with a lithium-ion transference number of 0.49 and high mechanical strength, can suppress lithium dendrite growth, which is beneficial for the application of batteries at high energy densities. Interestingly, after constant current cycling, the lithium metal surface of the lithium symmetric battery assembled with the NSIPM-EC / DMC electrolyte exhibits a distinct metallic luster similar to that of the original lithium sheet. The smooth SEM images further demonstrate the uniform lithium deposition at the lithium anode / electrolyte interface and its dendrite-suppressing effect. Figure 12 jl).

[0113] Electrochemical performance and battery performance testing of ionic polymer electrolyte membranes

[0114] The superior ionic conductivity and good electrode / electrolyte interface resistance of polymer separators play a crucial role in improving battery performance. Rate and cycle performance tests are excellent measures of battery electrochemical performance. This invention was conducted on a LAND testing system, and the practical application of the separator as a high-performance lithium metal battery separator was evaluated by constructing a LiFePO4|Li coin cell (model 2025). Charge-discharge tests were first performed at different rates, with six cycles at each rate, followed by long-term cycle performance testing at a suitable rate. At room temperature, the battery impedance of the three electrolytes is as follows: Figure 13 As shown in figure a, compared to the 145Ω interfacial resistance in a commercially available PP-1M LiPF6-EC / DMC electrolyte battery, the interfacial resistance of the NSIPM-1M LiPF6-EC / DMC-based battery is reduced to 116Ω, which is attributed to its high porosity and liquid absorption rate. The increase in polar groups such as ether bonds and disulfonamides promotes the compatibility of the electrolyte interface with organic solvents. Furthermore, in the electrolyte system without the addition of commercially available lithium salts, the interfacial resistance of NSIPM is 183Ω, significantly lower than the 450Ω of SIPM.

[0115] like Figure 13 As shown in b, the room temperature ionic conductivity of the NSIPM-1M LiPF6-EC / DMC electrolyte is 7.17 × 10⁻⁶. -4 Scm -1 The conductivity is higher than that of PP film in commercial electrolytes (5.09 × 10⁻⁶). -4 S cm -1Like most self-assembled polymer electrolytes, its high ionic conductivity makes it suitable for use in lithium metal batteries. More significantly, the NSIPM-EC / DMC electrolyte exhibits a room-temperature ionic conductivity of 8.15 × 10⁻⁶. -5 S cm -1 It is close to that of SIPM-EC / DMC electrolyte (4.74×10⁻⁶). -5 S cm -1 This is twice as much as that of the polymer LiPSBI, which releases free Li in organic solvents. + The increased content and the introduction of ether bonds improved the compatibility between the organic solvent and the polymer electrolyte. Furthermore, fitting data showed that the activation energy of the NSIPM-1M LiPF6-EC / DMC electrolyte was 16.329 kJ / mol, significantly lower than the 20.836 kJ / mol of the PP-1M LiPF6-EC / DMC system. This lower activation energy indicates that Li... + Less energy is required for electrolyte transfer.

[0116] like Figure 13 As shown in c and d, the battery based on NSIPM-EC / DMC electrolyte can achieve a discharge specific capacity of 167.5 mAh g at 0.1C and 1C. -1 and 129.6mAh g -1 It exhibits stable and reversible discharge capability, with a capacity higher than that of SIPM-EC / DMC electrolyte (145.1 mAh g). -1 and 115.9mAh g -1 ).

[0117] like Figure 13 As shown in Figure e, under 0.2C battery cycle testing, the initial discharge specific capacity of the battery based on NSIPM-EC / DMC electrolyte is 148.4 mAh g. -1 This is significantly higher than the 124.1 mAh g of the SIPM-EC / DMC electrolyte. -1 After 450 charge-discharge cycles, the former still maintains 116.3 mAh g. -1 The discharge capacity and coulombic efficiency of the first-generation discharge capacity were 98.9%, with only 21.6% of the initial capacity decaying, averaging only 0.048% decay per cycle. In contrast, the latter not only had a lower discharge capacity but also exhibited poor cycle stability.

[0118] Even at a relatively high rate of 1C, the NSIPM-EC / DMC battery exhibited stable electrochemical performance, with an initial discharge capacity of 122.9 mAh g⁻¹. -1 After 1000 charge / discharge cycles, it still has 70.6 mAh g. -1And the coulomb efficiency remains at 99.6% ( Figure 13 f). The high capacity of the battery is mainly attributed to the improved ionic conductivity and reduced interfacial resistance. The long cycle life is primarily due to the near-1 lithium-ion transference number of the NSIPM-EC / DMC electrolyte, which effectively suppresses lithium dendrite growth. The rate capability and cycle performance of both electrolytes were evaluated using a LiFePO4|Li battery.

[0119] These results indicate that, in the presence of LiPF6 electrolyte, the gel polymer electrolyte NSIPM exhibits superior interfacial impedance, lithium-ion transference number, ionic conductivity, and rate cycling performance compared to PP membranes. Furthermore, when using only a mixed organic solvent EC / DMC (1:1, v / v) as a plasticizer, the gel polymer electrolyte NSIPM demonstrates superior interfacial impedance, ionic conductivity, and rate cycling performance compared to SIPM.

Claims

1. A method for preparing an ionic polymer electrolyte LiPSBI, characterized by: The method specifically comprises the following steps: (1) Synthesis of OX-BMSI According to the proportion, p-toluenesulfonyl and potassium hydroxide are weighed and placed in a reaction bottle, and then deionized water is added and stirred until completely dissolved; the temperature of the obtained solution is adjusted to 75-85°C, and then 4,4'-oxybis(benzenesulfonyl chloride) is weighed and slowly added to the reaction bottle in batches; after the addition is completed, the reaction temperature is adjusted to 90-100°C and reacted for 10-15h; After the reaction is completed, hot dilute hydrochloric acid solution is added to the obtained product, and the pH of the product is adjusted to 7; then the obtained product is suction filtered, the filtrate is collected, and dilute hydrochloric acid solution is continuously added to the filtrate to adjust the pH of the filtrate to 1, to obtain a milky white precipitate, which is centrifuged to collect the white precipitate, recrystallized to obtain the bis(bis-sulfonimidate) benzene dimethyl precursor OX-BMSI. (2) Synthesis of OX-BCSI According to the proportion, OX-BMSI and potassium hydroxide in step (1) are weighed and sequentially added to a double-neck flask 1, and then deionized water is added, and after complete dissolution, the system is warmed to 85-95°C and condensed water is introduced; then potassium permanganate is slowly added to the double-neck flask 1 at 85-95°C, and after the addition is completed, constant temperature stirring is carried out for 10-15h; after the reaction is completed, it is cooled to room temperature, the obtained product is suction filtered, an excess of concentrated hydrochloric acid is added dropwise to the filtrate, and then suction filtered again to obtain a crude product, which is finally recrystallized and dried to obtain the bis(bis-sulfonimidate) benzene dicarboxylic acid precursor OX-BCSI. (3) Synthesis of LiPSBI According to the proportion, 4,4'-diaminodiphenyl sulfone and OX-BCSI are weighed and sequentially placed in a double-neck flask 2, and then anhydrous lithium chloride is added according to the proportion, condensed water is introduced, and the reaction system is filled with inert gas; then anhydrous azomethine pyrrolidine, pyridine and triphenyl phosphite are sequentially injected into the double-neck flask 2 under an inert atmosphere, and stirred and dissolved at room temperature; then the reaction system is heated and warmed to 95-105°C, and reacted for 20-30h at constant temperature; After the reaction is completed, it is cooled to room temperature, the obtained product is slowly poured into an excess of anhydrous methanol, and the methanol solution is stirred until the white solid is completely precipitated; suction filtered, the filtrate is removed, the filter cake is retained, washed, and a white product is obtained; dried; the dried product is taken out, and 0.165g of anhydrous LiOH in 100mL of methanol solution is used for lithiation twice, each for 12h, to ensure sufficient lithiation; after sufficient lithiation, suction filtration is carried out, the obtained filter cake is washed, and dried to obtain the ionic polymer electrolyte LiPSBI.

2. The method of claim 1, wherein: In step (1), the molar ratio of p-toluenesulfonyl to potassium hydroxide is 1:1; the molar ratio of p-toluenesulfonyl to 4,4'-oxybis(benzenesulfonyl chloride) is 4:

1.

3. The method of claim 1, wherein: In step (2), the molar ratio of OX-BMSI to potassium hydroxide is 1:2; the molar ratio of OX-BMSI to potassium permanganate is 2:

1.

4. The method of claim 1, wherein: In step (3), the molar ratio of 4,4'-diaminodiphenyl sulfone to OX-BCSI is 1:1; the molar ratio of anhydrous lithium chloride to OX-BCSI is 4:

1.

5. The ion-conducting polymer electrolyte LiPSBI prepared by the method of any one of claims 1-4.

6. Use of the ion-conducting polymer electrolyte LiPSBI prepared by the method of any one of claims 1-4 in the preparation of a novel ion-conducting polymer electrolyte porous membrane NSIPM.

7. A method for preparing a novel ionomeric polymer electrolyte porous membrane (NSIPM) characterized by: The steps are as follows: The ion-conducting polymer electrolyte LiPSBI and polyvinylidene-hexafluoropropylene of claim 5 are dissolved in dimethyl sulfoxide in the proportions to form a uniform solution; then the obtained solution is uniformly coated on the surface of a glass plate, dried to obtain the novel ion-conducting polymer electrolyte porous membrane NSIPM.

8. The novel ion-conducting polymer electrolyte porous membrane NSIPM prepared by the method of claim 7.

9. Use of the novel ion-conducting polymer electrolyte porous membrane NSIPM prepared by the method of claim 7 in lithium ion batteries.

10. A lithium ion battery comprising a positive electrode, a negative electrode, an electrolyte and a separator, characterized in that: The separator is the novel ion-conducting polymer electrolyte porous membrane NSIPM prepared by the method of claim 7.

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