Preparation method and application of perfluorosulfonic acid polymer emulsion
By preparing a perfluorosulfonic acid polymer emulsion and uniformly dispersing it in a polymer network, the problem of uneven dispersion of perfluorosulfonic acid materials in the polymer system was solved, improving the ion channel efficiency and interface stability of solid-state batteries, and realizing the reliability and safety of high-performance batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-03-24
AI Technical Summary
Existing perfluorosulfonic acid materials are difficult to disperse uniformly in polymer systems, resulting in insufficient ion channels, poor interfacial stability, and phase separation, which limits the performance and reliability of solid-state batteries.
By preparing a perfluorosulfonic acid polymer emulsion and uniformly dispersing it in a polymer network, nanoscale polar domains are formed, which improves the lithium salt dissociation efficiency and interfacial stability, while also improving the continuity of the membrane structure and mechanical strength.
The construction of highly polar continuous ion channels has been achieved, which improves the ionic conductivity, electrochemical stability and mechanical properties of the battery, making it suitable for large-area film deposition and mass production.
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Figure CN121726673A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of material preparation and polymer synthesis, and particularly relates to a preparation method and application of a perfluorosulfonic acid polymer emulsion. BACKGROUND
[0002] With the growing demand for high-performance energy storage systems in electric vehicles, portable electronic devices, and safety-sensitive fields, the reliable operation of batteries under high power output, high energy density, and complex environments has become a key technical bottleneck. Traditional lithium-ion batteries rely on liquid electrolytes to achieve ion transport, but the liquid system has inherent disadvantages such as high volatility, strong flammability, and poor mechanical stability. Under high temperature, high pressure difference, or long-term cycling conditions, liquid electrolytes are prone to leakage, swelling, and even thermal runaway, which severely limits their application in safety-critical scenarios. At the same time, the liquid electrolyte and electrode interface are prone to chemical and mechanical instability during the cycling process, and the repeated rupture and reconstruction of the interface film leads to continuous increase in battery impedance, making it difficult to guarantee cycle life and reliability.
[0003] To solve the above safety and stability problems, solid-state electrolytes are widely considered as an effective way to improve battery performance. Polymer solid-state electrolytes have important application prospects in all-solid-state batteries due to their good flexibility, easy processing, easy formation of close contact with electrodes, and suitability for thin films. However, the pure polymer system has obvious limitations: low room temperature ionic conductivity, ion transport limited by polymer chain segment movement; limited mechanical strength of the film body, difficult to suppress lithium dendrite growth under high current density, directly affecting the safety and cycle performance of solid-state batteries.
[0004] Perfluorosulfonic acid materials show significant advantages in improving the performance of electrolytes. The perfluorinated carbon backbone endows the material with excellent chemical resistance and thermal stability, and the side chain sulfonic acid group has strong polarity, which can provide more lithium salt dissociation sites, and is a key functional unit for building efficient ion channels. However, traditional perfluorosulfonic acid resins mainly exist in the form of dense membranes or blocks, which are difficult to fully integrate with the polymer matrix, leading to problems such as discontinuous phase distribution, weak interfacial bonding, and uncontrollable microphase structure. In addition, the solidification and processing process is complex, which is difficult to meet the preparation requirements of solid-state electrolytes with large area, light weight, and strong controllability.
[0005] The introduction of perfluorosulfonic acid in the form of emulsion into the polymer system provides a new design path for composite solid-state electrolyte. The emulsion can achieve uniform dispersion of perfluorosulfonic acid phase at the nanoscale, which helps to build continuous and high-polarity ion conduction channels in the polymer network. However, the existing technology still has obvious shortcomings: the emulsion particle size distribution is difficult to accurately control, the migration behavior of perfluorosulfonic acid during polymer solidification is unpredictable, the local enrichment or phase separation of the membrane body structure is prone to occur, and the film forming repeatability is poor. These problems directly limit the ionic conductivity, mechanical properties and electrochemical stability of the composite solid-state electrolyte, making it difficult to meet the practical application requirements of high-performance solid-state batteries.
[0006] Therefore, it is urgent to develop a preparation method of perfluorosulfonic acid polymer emulsion which has uniform structure, stable dispersion, mechanical and electrochemical properties, and is suitable for large-scale preparation. By uniformly introducing perfluorosulfonic acid emulsion into the polymer network, a high-polarity continuous ion channel can be constructed at the nanoscale, while the heat resistance, interface compatibility and overall structural stability of the membrane body can be improved, providing key material support for the next generation of solid-state batteries with high safety and high reliability. SUMMARY
[0007] The purpose of the present application is to solve the problems of weak lithium salt dissociation, insufficient ion channels, poor interface stability and phase separation during film forming in the existing polymer solid-state electrolyte. By introducing perfluorosulfonic acid emulsion, high-polarity sulfonic acid groups are uniformly dispersed in the polymer, thereby improving the ion migration efficiency and interface stability. At the same time, the present application overcomes the limitations of traditional perfluorosulfonic acid materials, such as difficulty in compounding with polymers, mechanical property degradation and uncontrollable preparation, and constructs a modified solid-state electrolyte film which can be prepared on a large scale, has uniform structure and has high conductivity and mechanical strength, thereby providing a reliable material basis for high-safety solid-state batteries.
[0008] The technical scheme provided by the present application is as follows:
[0009] To solve the above problems, the technical scheme adopted by the present application is as follows:
[0010] The present application discloses a preparation method and application of perfluorosulfonic acid polymer emulsion, characterized in that it comprises the following steps:
[0011] (1) A certain amount of deionized water is subjected to nitrogen deoxidation treatment, and then a certain amount of fluorine surfactant is added to form a stable weakened environment. Then, a certain amount of tetrafluoroethylene (TFE) and a certain amount of perfluoroethylene sulfonic acid fluoride alkoxy vinyl ether (PFSA-FVE) are added into a high-pressure corrosion-resistant reaction kettle to ensure the stable dispersion of monomers in the aqueous solution under the control of a certain pressure. After sufficient dissolution, a certain amount of potassium persulfate (KPS) is added and the temperature is raised to a certain temperature to cause a thermal polymerization reaction. Finally, the temperature is lowered and the exhaust is obtained to obtain a milky white perfluorosulfonic acid polymer emulsion.
[0012] (2) Commercial polyethylene (PE) separator was cleaned by ultrasonic in anhydrous ethanol to remove surface oil and impurities, then rinsed with deionized water and dried for use. The pretreated PE separator was placed in a plasma cleaning machine for surface activation treatment to enhance the surface wettability and film quality. A certain amount of perfluorosulfonic acid polymer emulsion was uniformly coated on the surface of the PE separator using a precision scraper, and then placed in a vacuum drying oven at a specific temperature for dehydration and densification treatment to obtain a perfluorosulfonic acid polymer emulsion modified separator with a specific thickness.
[0013] As a preferred scheme, in step (1), the volume of deionized water added is 100-150 mL, the mass of fluorine surfactant added is 1-5 mg, the mass of tetrafluoroethylene added is 20-25 mg, the mass of perfluoroethylene sulfonic acid fluoroalkoxy vinyl ether added is 30-35 mg, and the mass of potassium persulfate added is 5-10 mg.
[0014] As a preferred scheme, in step (2), the mass of perfluorosulfonic acid polymer emulsion added is 10-15 mg.
[0015] Compared with the prior art, the advantages of the present application are:
[0016] (1) The perfluorosulfonic acid polymer emulsion forms uniform nanoscale polar domains in the matrix, greatly improving the lithium salt dissociation energy and ion channel connectivity, so that the electrolyte has higher intrinsic ionic conductivity at room temperature.
[0017] (2) The emulsion modification improves the film-electrode interface energy matching and contact morphology, effectively reduces the interface impedance and suppresses the interface side reaction, and improves the long-term electrochemical stability.
[0018] (3) The perfluorosulfonic acid side chain provides a high oxidation stability window and chemical inertness, so that the electrolyte remains stable in structure and electrical performance in a high-voltage system, meeting the demand for high energy density applications.
[0019] (4) The emulsion dispersion avoids phase separation of solid additives, resulting in a dense and uniform film structure, significantly improving the film mechanical strength and enhancing the dendrite shielding ability, thereby improving the battery safety margin.
[0020] (5) The preparation process has mild conditions and high controllability, is suitable for continuous coating and large-area film formation, and can realize stable and scalable production of solid electrolyte thin films. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 The figure shows the actual appearance of the target product of Example 1.
[0022] Figure 2A scanning electron microscope image of the target product of Example 2 is shown.
[0023] Figure 3 A contact angle test image of the target product of Example 3 is shown. DETAILED DESCRIPTION
[0024] The present application is more fully described in connection with the following specific embodiments and the accompanying drawings, although the application is not limited thereto.
[0025] The experimental methods in the following examples are all conventional methods unless otherwise specified.
[0026] The materials, reagents, etc. used in the following examples can be obtained commercially unless otherwise specified.
[0027] Example 1
[0028] Method for preparing a perfluorosulfonic acid polymer emulsion modified PE separator:
[0029] (1) After deoxygenating 100 mL of deionized water by nitrogen, 2 mg of fluorine surfactant was added to form a stable weakened environment. Then it was poured into a high-pressure corrosion-resistant reaction kettle to add 20 mg of tetrafluoroethylene (TFE) and 30 mg of perfluoroethylene sulfonic acid fluoride alkoxy vinyl ether (PFSA-FVE), and the monomers were stably dispersed in the aqueous solution under the control of 0.5 MPa pressure. After sufficient dissolution, 5 mg of potassium persulfate (KPS) was added to raise the temperature to 60°C, and then a thermal polymerization reaction occurred. Finally, the temperature was lowered and the exhaust was obtained to obtain a milky white perfluorosulfonic acid polymer emulsion.
[0030] (2) The commercial polyethylene (PE) separator was cleaned with ultrasonic cleaning in anhydrous ethanol to remove surface oil and impurities, then washed with deionized water and dried for use. The pretreated PE separator was placed in a plasma cleaning machine for surface activation treatment to enhance the surface wettability and film quality. A precision scraper was used to uniformly coat 12 mg of perfluorosulfonic acid polymer emulsion on the surface of the PE separator, and it was placed in a vacuum drying oven at 60°C for dehydration and densification treatment to obtain a perfluorosulfonic acid polymer emulsion modified separator with a thickness of 15 μm.
[0031] As shown in Figure 1 , it is the actual appearance diagram of the perfluorosulfonic acid polymer emulsion dispersion prepared by the present application. As can be observed from the diagram, the emulsion is in a uniform milky white dispersion state, and the system has no obvious sedimentation, stratification or flocculation phenomenon, indicating that the dispersion has good stability and uniformity.
[0032] Example 2
[0033] Microscopic morphology analysis of perfluorosulfonic acid polymer emulsion modified PE separator:
[0034] The perfluorosulfonic acid emulsion obtained in Example 1 was used to modify PE separators and commercial PE separators were subjected to scanning electron microscope tests.
[0035] As shown in FIG. 1, the perfluorosulfonic acid emulsion modified PE separator shows a much smoother and more continuous surface structure than the commercial PE separator. Figure 2 As shown in FIG. 1, the perfluorosulfonic acid emulsion modified PE separator shows a much smoother and more continuous surface structure than the commercial PE separator.
[0036] Example 3
[0037] Analysis of the electrophilic electrolyte properties of the perfluorosulfonic acid polymer emulsion modified PE separator:
[0038] The perfluorosulfonic acid emulsion obtained in Example 1 was used to modify PE separators and commercial PE separators were subjected to contact angle tests.
[0039] As shown in FIG. 1, the perfluorosulfonic acid emulsion modified PE separator shows a much smoother and more continuous surface structure than the commercial PE separator. Figure 3 As shown in FIG. 2, the perfluorosulfonic acid emulsion modified PE separator shows significantly enhanced wettability on the electrode surface, with a contact angle as low as 7.3°. Such excellent wettability not only enables the electrolyte to achieve more sufficient and closer interface spreading on the electrode surface, thereby effectively reducing the interface contact impedance, but also significantly promotes the rapid and uniform migration of Li + ions at the interface, which is conducive to further improving the overall electrochemical performance of the battery under high rate and long cycle conditions.
Claims
1. This invention discloses a method for preparing a perfluorosulfonic acid polymer emulsion and its application, characterized in that, Includes the following steps: (1) After nitrogen deoxygenation treatment of a certain amount of deionized water, a certain amount of fluorinated surfactant is added to form a stable weakening environment. Then, it is poured into a high-pressure corrosion-resistant reactor, and a certain amount of tetrafluoroethylene (TFE) and perfluoroethylene sulfonyl fluoroalkoxy vinyl ether (PFSA-FVE) are added. The monomer is stably dispersed in the aqueous solution under controlled pressure. After complete dissolution, a certain amount of potassium persulfate (KPS) is added, and the temperature is raised to a specific level to initiate a thermal polymerization reaction. Finally, the mixture is cooled and the gas is vented to obtain a milky white perfluorosulfonic acid polymer emulsion. (2) Commercial polyethylene (PE) membranes were ultrasonically cleaned in anhydrous ethanol to remove surface oil and impurities, then rinsed with deionized water and dried for use. The pretreated PE membranes were then placed in a plasma cleaner for surface activation to enhance surface wettability and film quality. A certain amount of perfluorosulfonic acid polymer emulsion was uniformly coated onto the PE membrane surface using a precision scraper, and then placed in a vacuum drying oven at a specific temperature for dehydration and densification treatment to obtain a perfluorosulfonic acid polymer emulsion-modified membrane with a specific thickness.
2. The present invention, according to claim 1, discloses a method for preparing a perfluorosulfonic acid polymer emulsion and its application, characterized in that, In step (1), the volume of deionized water added is 100-150 mL, the mass of the added fluorinated surfactant is 1-5 mg, the mass of the added tetrafluoroethylene is 20-25 mg, the mass of the added perfluoroethylene sulfonyl fluoroalkoxy vinyl ether is 30-35 mg, and the mass of the added potassium persulfate is 5-10 mg.
3. The present invention, according to claim 1, discloses a method for preparing a perfluorosulfonic acid polymer emulsion and its application, characterized in that, In step (2), the mass of the added perfluorosulfonic acid polymer emulsion is 10-15 mg.
4. A perfluorosulfonic acid polymer emulsion-modified PE separator obtained by the preparation method according to any one of claims 1 to 3, characterized in that, By introducing a perfluorosulfonic acid polymer emulsion into the membrane substrate, highly polar sulfonic acid groups are uniformly distributed within the membrane, forming continuous ion conduction channels and improving interfacial stability. The emulsion morphology imparts better uniformity and density to the coating layer, thereby significantly improving the room temperature ionic conductivity and electrochemical stability of the solid electrolyte, and enhancing the safety and reliability of the battery under high voltage and long-cycle conditions.