Preparation method and application of synergistic ultra-thin polymer solid-state electrolyte
By constructing a synergistic system of MOFs, dual polymers, and ionic liquid electrolytes, a highly efficient nanofiber membrane was prepared, which solved the problems of low ionic conductivity and poor interfacial contact of polymer solid electrolytes at room temperature, and achieved efficient lithium-ion transport and stability in lithium-ion batteries.
Patent Information
- Application Number
- CN202610355613.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-23
- Publication Date
- 2026-06-16
AI Technical Summary
Existing polymer solid electrolytes have low ionic conductivity at room temperature and poor contact with the electrode interface, which limits their practical application. Furthermore, gel electrolytes formed by directly adding ionic liquids have reduced mechanical properties and are prone to leakage.
A multi-component solid electrolyte consisting of MOFs, a dual polymer and an ionic liquid electrolyte system was constructed using electrospinning technology and post-processing. Nanofiber membranes were prepared by electrospinning and formed into dense membranes after hot pressing, thereby realizing the synergistic effect of the ion transport network.
It significantly improves lithium-ion transport efficiency and enhances the overall performance of the electrolyte, including ionic conductivity, mechanical strength, and interface stability, making it suitable for lithium metal batteries and lithium-ion batteries.
Smart Images
Figure CN122224950A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a method for preparing and applying a synergistic ultrathin polymer solid electrolyte. Background Technology
[0002] With the increasing demand for high-energy-density and safe energy storage devices, traditional liquid lithium-ion batteries, due to safety hazards such as flammability and leakage, are no longer able to meet future development requirements. Solid-state lithium batteries, because they use non-flammable solid electrolytes instead of liquid electrolytes, are considered the core technology of the next generation of high-safety, high-energy-density battery systems.
[0003] Currently, solid electrolytes are mainly classified into inorganic ceramic / glass electrolytes and organic polymer electrolytes. Polymer solid electrolytes (such as PEO, PAN, PVDF-HFP, etc.) have attracted much attention due to their light weight, good flexibility, and strong processability. However, single polymer electrolytes typically have low ionic conductivity at room temperature and poor contact with the electrode interface, limiting their practical applications. To address this issue, researchers have attempted to add inorganic fillers or plasticizers to the polymer matrix. Ionic liquids (ILs) possess advantages such as low volatility, non-flammability, and a wide electrochemical window. Combining them with polymers can prepare ion gel electrolytes, effectively improving ionic conductivity. However, gel electrolytes formed by directly adding ionic liquids often exhibit decreased mechanical properties, and ionic liquids are prone to leakage. Metal-organic frameworks (MOFs) materials, due to their high specific surface area, tunable pore structure, and abundant metal active sites, show great potential in ion conduction and electrolyte modification.
[0004] This application combines the advantages of MOFs, ionic liquids and polymers, and constructs a multi-component solid electrolyte with synergistic effects through electrospinning technology and post-processing, aiming to solve the problem that it is difficult to achieve ionic conductivity, mechanical strength and interfacial stability simultaneously in the prior art. Summary of the Invention
[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for preparing and applying a synergistic ultrathin polymer solid electrolyte. By introducing MOFs, dual polymers, and an ionic liquid electrolyte system, a multi-scale ion transport network is constructed, thereby significantly improving lithium-ion transport efficiency and enhancing the overall performance of the electrolyte.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a synergistic ultrathin polymer solid electrolyte, comprising the following steps:
[0007] S1. Select Zn or Cu salt as the metal source and react it with organic ligands in a solvent to prepare MOF materials;
[0008] S2. Dissolve one of PAN, PVDF, or PVDF-HFP in DMF and blend it with Pebax. Stir at room temperature for 12 hours to obtain solution a.
[0009] S3. Weigh the MOF material prepared in S1 and disperse it evenly in solution a. After sonication for 30 min, stir at room temperature for 12 h to obtain solution b.
[0010] S4. Solution b was prepared into an electrospun nanofiber membrane by electrospinning, and then dried in a vacuum oven at 60°C for 12 h to remove residual solvent.
[0011] S5. Prepare a mixed solution of lithium salt and ionic liquid with a concentration of 0.5–5 M, and stir until the lithium salt is completely dissolved to obtain solution c;
[0012] S6. The nanofiber membrane obtained in S4 is immersed in solution c, kept at 120℃ in a vacuum oven for 12 h, and then subjected to hot pressing to obtain a dense polymer solid electrolyte membrane.
[0013] Preferably, in S1, the Zn salt is one or more of zinc nitrate, zinc acetate, or zinc chloride; the Cu salt is one or more of copper nitrate, copper acetate, copper chloride, or copper sulfate; and the organic ligand is one or more of trimellitic acid, terephthalic acid, 2-methylimidazole, imidazole, and their derivatives.
[0014] Preferably, in S2, the mass ratio of Pebax:PAN / PVDF / PVDF-HFP is 1:1–1:8.
[0015] Preferably, in S2, the solid content of the spinning solution is 12%–15%.
[0016] Preferably, in S3, the mass of MOF is 1%–10% of the polymer in S2.
[0017] Preferably, in S4, the electrospinning parameters are: positive pressure 16.0 kV, negative pressure -2.0 kV, distance between the injection end and the collection end approximately 20 cm, and pump feed rate set to 0.08 mL / min. -1 .
[0018] Preferably, in S5, the lithium salt is selected from one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, or lithium bis(fluorosulfonyl)imide.
[0019] Preferably, in S5, the ionic liquid is selected from 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI); 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIM-TFSI); N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide (PYR14-TFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM-FSI), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIM-FSI), N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide (N1113-TFSI), N-trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide (N1114-TFSI), or N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide (N1114-TFSI). The product is one or more of the following: 1-ethyl-3-methylimidazolium difluorosulfonylimide (N1114-FSI), 1-ethyl-3-methylimidazolium chloride (EMIM-Cl), 1-ethyl-3-methylimidazolium bromide (EMIM-Br), 1-butyl-3-methylimidazolium chloride (BMIM-Cl), 1-butyl-3-methylimidazolium bromide (BMIM-Br), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF4), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4), 1-ethyl-3-methylimidazolium hexafluorophosphate (EMIM-PF6), and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6).
[0020] Preferably, in S6, the hot-pressing temperature is 70–130°C, the pressure is 1–10 MPa, and the time is 1–10 min; the thickness of the resulting dense polymer solid electrolyte membrane is 5–15 μm.
[0021] The present invention also provides an application of the ultrathin polymer solid electrolyte obtained by the above preparation method in lithium metal batteries.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] 1. This invention constructs a continuous and efficient lithium-ion transport channel through the synergistic combination of a metal-organic framework, a dual polymer matrix, and an ionic liquid lithium salt system, which is beneficial to improving the ionic conductivity and lithium-ion migration ability of solid electrolytes.
[0024] 2. The preparation method of this invention is simple, and the resulting composite solid electrolyte has good mechanical flexibility, thermal stability and interfacial compatibility, and can be widely used in lithium metal batteries, lithium-ion batteries and other solid energy storage devices. Attached Figure Description
[0025] Figure 1 This is an XRD data diagram of HKUST-1 in Embodiment 1 of the present invention;
[0026] Figure 2This is a SEM image of HKUST-1 in Embodiment 1 of the present invention;
[0027] Figure 3 This is a surface SEM image of the polymer solid electrolyte membrane of Example 1 of the present invention;
[0028] Figure 4 This is a comparison chart of the cycle performance of Li / / Li coin cells assembled with polymer solid electrolyte membranes in Example 1 and Comparative Example 1 of the present invention.
[0029] Figure 5 This is a comparison chart of the cycle performance of Li / / NCM811 coin cells assembled with polymer solid electrolyte membranes in Example 1 and Comparative Example 1 of the present invention. Detailed Implementation
[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the scope of protection of the present invention. The embodiments described in this invention are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0031] Example 1
[0032] S1. Weigh 2.42 g of copper nitrate trihydrate and dissolve it in 50 mL of anhydrous methanol to obtain a metal salt solution; separately weigh 1.05 g of trimesic acid and dissolve it in 50 mL of anhydrous methanol to obtain a ligand solution. Slowly add the ligand solution to the metal salt solution and stir continuously at room temperature for 12 h to form a blue precipitate. Centrifuge the precipitate, wash it three times with anhydrous methanol, and dry it in a vacuum oven at 80 °C for 12 h to obtain HKUST-1 powder, as shown below. Figure 1 , Figure 2 As shown.
[0033] S2. Weigh 0.60 g PAN and 0.15 g Pebax and add them to 5 mL DMF. Stir magnetically at room temperature for 12 h to obtain a homogeneous and transparent polymer solution a.
[0034] S3. Weigh 0.075 g of HKUST-1 powder and add it to the above solution a. First, disperse it by ultrasonication for 30 min, and then stir it at room temperature for 12 h to obtain a uniformly dispersed solution b.
[0035] S4. Transfer the above solution b into a syringe, apply a positive voltage of 16.0 kV and a negative voltage of -2.0 kV, with the distance between the injection end and the collection end approximately 20 cm, and set the pump feed rate to 0.08 mL / min. -1 The composite nanofiber membrane was collected. The obtained fiber membrane was dried in a vacuum oven at 60℃ for 12 h to remove residual solvent;
[0036] S5. Weigh an appropriate amount of LiTFSI in the glove box and add it to EMIM-TFSI to prepare a lithium salt / ionic liquid mixed solution with a concentration of 1 M. Stir at room temperature for 6 h until the lithium salt is completely dissolved to obtain solution c.
[0037] Solution c was uniformly dropped onto the surface of the composite nanofiber membrane to fully wet and fill the pores. The wetted membrane was then placed in a vacuum oven at 120°C for 12 h, followed by hot pressing at 100°C and 2 MPa for 5 min to obtain a dense polymer solid electrolyte membrane with a thickness of 8.6 μm. Figure 3 As shown.
[0038] Example 2
[0039] S1. Weigh 2.20 g of zinc nitrate hexahydrate and dissolve it in 40 mL of methanol to obtain a zinc salt solution; separately weigh 4.93 g of 2-methylimidazole and dissolve it in 40 mL of methanol to obtain a ligand solution. Quickly pour the ligand solution into the zinc salt solution and stir the reaction at room temperature for 6 h. After the reaction is complete, centrifuge the resulting white precipitate, wash it three times with methanol, and dry it under vacuum at 80 °C for 12 h to obtain ZIF-8 powder;
[0040] S2. Weigh 0.65 g of PVDF-HFP and 0.15 g of Pebax and add them to 5 mL of DMF. Stir magnetically at room temperature for 12 h to obtain a homogeneous and transparent polymer solution a.
[0041] S3. Weigh 0.1 g of ZIF-8 powder and add it to the above solution a. First, disperse it by ultrasonication for 30 min, and then stir it at room temperature for 12 h to obtain a uniformly dispersed solution b.
[0042] S4. Transfer the above solution b into a syringe, apply a positive voltage of 16.0 kV and a negative voltage of -2.0 kV, with the distance between the injection end and the collection end approximately 20 cm, and set the pump feed rate to 0.08 mL / min. -1 The composite nanofiber membrane was collected. The obtained fiber membrane was dried in a vacuum oven at 60℃ for 12 h to remove residual solvent;
[0043] S5. Weigh an appropriate amount of LiFSI in the glove box and add it to EMIM-FSI to prepare a lithium salt / ionic liquid mixed solution with a concentration of 1.5 M. Stir at room temperature for 6 h until the lithium salt is completely dissolved to obtain solution c.
[0044] Solution c was uniformly dropped onto the surface of the composite nanofiber membrane to fully wet and fill the pores of the membrane. The wetted membrane was then placed in a vacuum oven at 120°C for 12 h and subsequently hot-pressed at 100°C and 5 MPa for 2 min to obtain a dense polymer solid electrolyte membrane with a thickness of 8.2 μm.
[0045] Example 3
[0046] S1. Weigh 2.97 g of zinc nitrate hexahydrate and dissolve it in 50 mL of ethanol to obtain a zinc salt solution; separately weigh 1.05 g of trimesic acid and dissolve it in 50 mL of a DMF / ethanol mixed solvent to obtain a ligand solution. Mix the two solutions and stir at room temperature for 12 h to form a white precipitate. Centrifuge the precipitate, wash it three times with ethanol, and dry it under vacuum at 80 °C for 12 h to obtain Zn-BTC powder.
[0047] S2. Weigh 0.65 g PAN and 0.1 g Pebax and add them to 5 mL DMF. Stir magnetically at room temperature for 12 h to obtain a homogeneous and transparent polymer solution a.
[0048] S3. Weigh 0.1 g of ZIF-8 powder and add it to the above solution a. First, disperse it by ultrasonication for 30 min, and then stir it at room temperature for 12 h to obtain a uniformly dispersed solution b.
[0049] S4. Transfer the above solution b into a syringe, apply a positive voltage of 16.0 kV and a negative voltage of -2.0 kV, with the distance between the injection end and the collection end approximately 20 cm, and set the pump feed rate to 0.08 mL / min. -1 The composite nanofiber membrane was collected. The obtained fiber membrane was dried in a vacuum oven at 60℃ for 12 h to remove residual solvent;
[0050] S5. Weigh an appropriate amount of LiTFSI in a glove box and add it to N-trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide to prepare a lithium salt / ionic liquid mixed solution with a concentration of 1.5 M. Stir at room temperature for 6 h until the lithium salt is completely dissolved to obtain solution c.
[0051] Solution c was uniformly dropped onto the surface of the composite nanofiber membrane to fully wet and fill the pores of the membrane. The wetted membrane was then placed in a vacuum oven at 120°C for 12 h and subsequently hot-pressed at 90°C and 5 MPa for 2 min to obtain a dense polymer solid electrolyte membrane with a thickness of 8.5 μm.
[0052] Comparative Example 1
[0053] S1. Weigh 0.75 g PAN and add it to 5 mL DMF. Stir magnetically at room temperature for 12 h to obtain a homogeneous and transparent polymer solution a.
[0054] S2. Transfer the above solution a into a syringe, apply a positive voltage of 16.0 kV and a negative voltage of -2.0 kV, with the distance between the injection end and the collection end approximately 20 cm, and set the pump feed rate to 0.08 mL / min. -1 The composite nanofiber membrane was collected. The obtained fiber membrane was dried in a vacuum oven at 60℃ for 12 h to remove residual solvent;
[0055] S3. Weigh an appropriate amount of LiTFSI in the glove box and add it to EMIM-TFSI to prepare a lithium salt / ionic liquid mixed solution with a concentration of 1 M. Stir at room temperature for 6 h until the lithium salt is completely dissolved to obtain solution b.
[0056] Solution b was uniformly dropped onto the surface of the composite nanofiber membrane to fully wet and fill the pores of the membrane. The wetted membrane was then placed in a vacuum oven at 120°C for 12 h and subsequently hot-pressed at 100°C and 2 MPa for 5 min to obtain a dense polymer solid electrolyte membrane with a thickness of 8.6 μm.
[0057] The composite polymer solid electrolyte membranes prepared in the above examples and comparative examples were cut into circles with a size of 19 mm, and coin cells were assembled using lithium sheets with a diameter of 16 mm. The coin cells used were CR2032 type purchased from Shenzhen Kelude Company.
[0058] from Figure 1 As can be seen from Figure 2, the highly crystalline HKUST-1 material was successfully synthesized, with no obvious impurities, a complete and stable structure, and a regular polyhedral structure. The MOF crystals grew fully and had good structural order, which is conducive to the construction of stable ion transport channels. Figure 3 The uniform, porous, three-dimensionally cross-linked nanofiber network facilitates the construction of continuous Li⁺ transport pathways and enhances overall interface stability. Compared to the comparative example, Example 1 exhibits an extremely stable voltage response during long-term cycling, indicating that this system can effectively regulate lithium-ion deposition behavior and suppress dendrite growth, thereby significantly improving the cycling stability of the symmetric battery. Figure 4 ).from Figure 5 As can be seen, Example 1 exhibits significant advantages in both cycle stability and coulombic efficiency. This is mainly attributed to the synergistic effect of the MOF structure in regulating lithium-ion migration, the ionic liquid in optimizing the interfacial environment, and the nanofiber network in constructing ion transport channels, thereby effectively stabilizing the electrode / electrolyte interface and suppressing side reactions.
[0059] In summary, the solid electrolyte membrane obtained by this invention possesses a uniform and continuous nanofiber network structure, with tightly interwoven fibers and uniformly distributed pores, which is beneficial for ionic liquid adsorption and lithium-ion transport. Electrochemical tests show that the coulombic efficiency of this electrolyte remains at a high level throughout the cycling process after the battery is assembled, and the charge-discharge process is stable, indicating that it has good interfacial stability and cycle reversibility.
[0060] The descriptions and practices disclosed in this invention are readily apparent and understandable to those skilled in the art, and various modifications and refinements can be made without departing from the principles of this invention. Therefore, any modifications or improvements made without departing from the spirit of this invention should also be considered within the scope of protection of this invention.
Claims
1. A method for preparing a synergistic ultrathin polymer solid electrolyte, characterized in that, Includes the following steps: S1. Select Zn or Cu salt as the metal source and react it with organic ligands in a solvent to prepare MOF materials; S2. Dissolve one of PAN, PVDF, or PVDF-HFP in DMF and blend it with Pebax. Stir at room temperature for 12 h to obtain solution a. S3. Weigh the MOF material prepared in S1 and disperse it evenly in solution a. After sonication for 30 min, stir at room temperature for 12 h to obtain solution b. S4. Solution b was prepared into an electrospun nanofiber membrane by electrospinning, and then dried in a vacuum oven at 60°C for 12 h to remove residual solvent. S5. Prepare a mixed solution of lithium salt and ionic liquid with a concentration of 0.5–5 M, and stir until the lithium salt is completely dissolved to obtain solution c; S6. The nanofiber membrane obtained in S4 is immersed in solution c, kept at 120℃ in a vacuum oven for 12 h, and then subjected to hot pressing to obtain a dense polymer solid electrolyte membrane.
2. The method for preparing a synergistic ultrathin polymer solid electrolyte according to claim 1, characterized in that, In S1, the Zn salt is one or more of zinc nitrate, zinc acetate, or zinc chloride; the Cu salt is one or more of copper nitrate, copper acetate, copper chloride, or copper sulfate; and the organic ligand is one or more of trimesic acid, terephthalic acid, 2-methylimidazole, imidazole, and their derivatives.
3. The method for preparing a synergistic ultrathin polymer solid electrolyte according to claim 1, characterized in that, In S2, the mass ratio of Pebax:PAN / PVDF / PVDF-HFP is 1:1–1:
8.
4. The method for preparing a synergistic ultrathin polymer solid electrolyte according to claim 1, characterized in that, In S2, the solid content of the spinning solution is 12%–15%.
5. The method for preparing a synergistic ultrathin polymer solid electrolyte according to claim 1, characterized in that, In S3, the mass of MOF is 1%–10% of the polymer in S2.
6. The method for preparing a synergistic ultrathin polymer solid electrolyte according to claim 1, characterized in that, In S4, the electrospinning parameters are: positive pressure 16.0 kV, negative pressure -2.0 kV, distance between the injection end and the collection end 20 cm, and pump feed rate set to 0.08 mL / min. -1 .
7. The method for preparing a synergistic ultrathin polymer solid electrolyte according to claim 1, characterized in that, In S5, the lithium salt is selected from one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, or lithium bis(fluorosulfonyl)imide.
8. The method for preparing a synergistic ultrathin polymer solid electrolyte according to claim 1, characterized in that, In S5, the ionic liquid selected is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium bis(fluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium bis(fluoromethanesulfonyl)imide, N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide, N-trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide, or N- One or more of the following: trimethyl-N-butylammonium difluorosulfonylimide, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium hexafluorophosphate.
9. The method for preparing a synergistic ultrathin polymer solid electrolyte according to claim 1, characterized in that, In S6, the hot-pressing temperature is 70–130℃, the pressure is 1–10 MPa, and the time is 1–10 min; the thickness of the resulting dense polymer solid electrolyte membrane is 5–15 μm.
10. The application of an ultrathin polymer solid electrolyte obtained by the preparation method according to any one of claims 1-9 in a lithium metal battery.