Preparation and application of perfluorosulfonic acid ion exchange membrane

Abstract

This invention discloses the preparation and application of a perfluorosulfonic acid ion exchange membrane. The preparation method includes the following steps: preparing a support layer using an aromatic organic compound containing amino functional groups; coating the support layer with a perfluorosulfonic acid ion exchange membrane resin, and curing it to form an ion exchange membrane on the surface of the support layer; and peeling the ion exchange membrane off the surface of the support layer. This invention applies the perfluorosulfonic acid ion exchange membrane prepared by the above method to a vanadium redox flow battery. The perfluorosulfonic acid ion exchange membrane prepared by this invention exhibits good ion selectivity and mechanical properties, and its application in the preparation of vanadium redox flow batteries results in excellent electrical performance. This invention features a simple and practical preparation method, high production efficiency, and promising prospects for industrial application.

Description

Technical Field

[0001] This invention relates to a method for preparing an ion exchange membrane, and more particularly to the preparation and application of a perfluorosulfonic acid ion exchange membrane for use in vanadium redox flow batteries. Background Technology

[0002] Flow batteries are a large-scale electrochemical energy storage technology with advantages such as long cycle life, high safety, and independent power and capacity. They can be widely used in energy storage for renewable energy generation, such as wind and solar power, enabling the large-scale application of renewable energy. Among them, vanadium redox flow battery energy storage technology has become one of the preferred technologies for large-scale, high-efficiency energy storage due to its high safety, long life, large output power and energy storage capacity, good charge-discharge cycle performance, and environmental friendliness.

[0003] Ion exchange membranes are one of the key materials in vanadium redox flow batteries. They prevent the cross-mixing of vanadium ions in the positive and negative electrode electrolytes while simultaneously transferring hydrogen ions to form the battery circuit. Their performance directly affects the performance of the battery system. An ideal ion exchange membrane should possess high ion selectivity, high ion conductivity, high chemical stability, and low cost. Currently, the most widely used commercial membrane is the perfluorosulfonic acid ion exchange membrane (Nafion) produced by DuPont. However, its relatively poor ion selectivity compared to non-fluorinated ion exchange membranes and its high price limit its industrial application. Summary of the Invention

[0004] Objective of this invention: The objective of this invention is to provide a method for preparing a perfluorosulfonic acid ion exchange membrane, thereby solving the problem of how to prepare a perfluorosulfonic acid ion exchange membrane with high ion selectivity. Another objective of this invention is to propose an application of the perfluorosulfonic acid ion exchange membrane in a vanadium redox flow battery, thereby solving the problem of how to prepare a vanadium redox flow battery.

[0005] Technical solution: The preparation method of a perfluorosulfonic acid ion exchange membrane according to the present invention includes the following steps:

[0006] (1) A support layer was prepared using aromatic organic compounds containing amino functional groups;

[0007] (2) A perfluorosulfonic acid ion exchange membrane resin is coated on the support layer and cured to form an ion exchange membrane on the surface of the support layer;

[0008] (3) Peel the ion exchange membrane off the surface of the support layer.

[0009] This invention prepares a perfluorosulfonic acid ion exchange membrane by forming an ion exchange membrane layer on a support layer and then peeling off the ion exchange membrane layer. During the peeling process, a small amount of support layer components remain on the surface of the ion exchange membrane, thereby effectively improving the ion selectivity coefficient of the perfluorosulfonic acid ion exchange membrane without affecting the mechanical properties of the membrane.

[0010] Preferably, in step (1), the method for preparing the support layer includes the following steps:

[0011] (11) Dissolve the aromatic organic compound containing the amino functional group in an organic solvent and stir thoroughly to prepare a homogeneous blend solution;

[0012] (12) Pour the blended solution onto a plate, scrape it flat and evaporate the solvent to obtain the support layer.

[0013] Preferably, the aromatic organic compound containing an amino functional group includes at least one of 1,2-phenylenediamide, 1,3-phenylenediamide, 1,4-phenylenediamide, and 1,3,5-phenyltricarboxamide, and the organic solvent is at least one of dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone, and N,N-dimethylformamide.

[0014] Preferably, in step (11), the molar ratio of the organic solvent to the aromatic organic compound containing the amino functional group is 100:1-100; the stirring conditions are to stir thoroughly at a temperature of 50-60°C for 12-36 hours.

[0015] Preferably, in step (12), the solvent evaporation time is at least 10 seconds.

[0016] Preferably, in step (2), the method for coating the support layer with perfluorosulfonic acid ion exchange membrane resin is as follows: immersing the support layer in a perfluorosulfonic acid ion exchange membrane resin solution at 30-50°C for at least 5 seconds and then removing it; the curing method is as follows: transferring the support layer coated with the perfluorosulfonic acid ion exchange membrane resin solution into a poor solvent for curing for at least 30 minutes. The formation of the bilayer composite membrane in this step is based on the formation of the following chemical bonds:

[0017]

[0018] Through this chemical bond, a portion of 1,2-phenylenediamide is attached to the surface of the membrane during the stripping of the perfluorosulfonic acid ion exchange membrane.

[0019] Preferably, the solvent of the perfluorosulfonic acid ion exchange membrane resin solution is at least one of dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone, and N,N-dimethylformamide, and the concentration of the solution is 5-60 wt%; the unsuitable solvent is at least one of water, ethanol, isopropanol, or acetone.

[0020] Preferably, the concentration of the perfluorosulfonic acid ion exchange membrane resin solution is 10-20 wt%.

[0021] Preferably, the thickness of the support layer is at least 10 μm.

[0022] Another aspect of the present invention discloses the application of the perfluorosulfonic acid ion exchange membrane prepared by the above method in a vanadium redox flow battery.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0024] The perfluorosulfonic acid ion exchange membrane prepared by this invention has good ion selectivity and mechanical properties. When applied to the preparation of vanadium redox flow batteries, it enables the batteries to have excellent electrical performance.

[0025] This invention features a simple and practical preparation method, high production efficiency, and promising prospects for industrial application. Attached Figure Description

[0026] Figure 1 This is a microscopic morphology diagram of the perfluorosulfonic acid ion exchange membrane prepared according to the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0028] Example 1: A method for preparing a perfluorosulfonic acid ion exchange membrane is as follows:

[0029] (1) Dissolve 1,2-benzenediamide in dimethyl sulfoxide and stir thoroughly at 55°C for 24 hours to prepare a homogeneous blend solution. The molar ratio of dimethyl sulfoxide to 1,2-benzenediamide is 100:50.

[0030] (2) Pour the blended solution onto a plate and apply it to a stainless steel plate using a 10μm scraper. Allow the solvent to evaporate for 10 seconds, and the solution will solidify to form a support layer. Then, immerse the support layer in a DMSO solution containing 20%wt perfluorosulfonic acid ion exchange membrane resin (Suzhou Kerun NEPEM-1000) at 40°C for 10 seconds. After that, remove the support layer and transfer it to water to solidify for 60 minutes, forming an ion exchange membrane on the surface of the support layer.

[0031] (3) After curing, the support layer is peeled off using conventional physical methods such as pulling or tearing, resulting in a perfluorosulfonic acid ion-conducting membrane containing only a dense separation layer, with a membrane thickness of 0.5 μm. Figure 1 As shown.

[0032] Example 2: A method for preparing a perfluorosulfonic acid ion exchange membrane is as follows:

[0033] (1) Dissolve 1,3-benzenedicaramide in dimethylacetamide and stir thoroughly at 50°C for 36 hours to prepare a homogeneous blend solution. The molar ratio of dimethylacetamide to 1,3-benzenedicaramide is 100:10.

[0034] (2) Pour the blended solution onto a plate and apply it to the Teflon plate using a 50μm doctor blade. Allow the solvent to evaporate for 10 minutes, and the solution will solidify to form a support layer. Then, immerse the support layer in a DMAC solution containing 10% wt perfluorosulfonic acid ion exchange membrane resin at 50°C for 30 seconds. After that, remove the support layer and transfer it to water to solidify for 30 minutes to form an ion exchange membrane on the surface of the support layer.

[0035] (3) After curing, the support layer is peeled off by conventional physical methods such as pulling or tearing to obtain a perfluorosulfonic acid ion-conducting membrane containing only a dense separation layer.

[0036] Example 3: A method for preparing a perfluorosulfonic acid ion exchange membrane is as follows:

[0037] (1) Dissolve 1,4-benzenediamide in N-methylpyrrolidone and stir thoroughly at 60°C for 12 h to prepare a homogeneous blend solution. The molar ratio of N-methylpyrrolidone to 1,4-benzenediamide is 100:100.

[0038] (2) Pour the blended solution onto a plate and apply it to a stainless steel plate using a 20μm scraper. Allow the solvent to evaporate for 100s and cure to form a support layer. Then, immerse the support layer in an NMP solution containing 60%wt perfluorosulfonic acid ion exchange membrane resin at 30°C for 5s. Remove the support layer and transfer it to water to cure for 45min, forming an ion exchange membrane on the surface of the support layer.

[0039] (3) After curing, the support layer is peeled off by conventional physical methods such as pulling or tearing to obtain a perfluorosulfonic acid ion-conducting membrane containing only a dense separation layer.

[0040] Example 4: A method for preparing a perfluorosulfonic acid ion exchange membrane is as follows:

[0041] (1) Dissolve 1,3,5-benzenetriformamide in N,N-dimethylformamide and stir thoroughly at 40°C for 24 hours to prepare a homogeneous blend solution. The molar ratio of N,N-dimethylformamide to 1,3,5-benzenetriformamide is 100:30.

[0042] (2) Pour the blended solution onto a plate and apply it to the Teflon plate using a 15μm doctor blade. Allow the solvent to evaporate for 1 minute and cure to form a support layer. Then, immerse the support layer in a DMSO solution containing 5% wt perfluorosulfonic acid ion exchange membrane resin at 50°C for 30 seconds. After that, remove it and transfer it to water to cure for 30 minutes to form an ion exchange membrane on the surface of the support layer.

[0043] (3) After curing, the support layer is peeled off by conventional physical methods such as pulling or tearing to obtain a perfluorosulfonic acid ion-conducting membrane containing only a dense separation layer.

[0044] Comparative Example 1: Everything else is the same as in Example 1, except that:

[0045] Without preparing a support layer, a perfluorosulfonic acid ion exchange membrane with a thickness of 0.5 μm was prepared by directly coating a DMSO solution of perfluorosulfonic acid ion exchange membrane resin onto a stainless steel plate.

[0046] Comparative Example 2: A commercially available Nafion 117 membrane with a thickness of 0.5 μm was used as the ion exchange membrane sample.

[0047] Comparative Example 3: Ion exchange membranes were prepared as follows:

[0048] 1,2-Phenylacetamide was added to a DMSO solution containing 20% ​​wt perfluorosulfonic acid ion exchange membrane resin. The molar ratio of dimethyl sulfoxide to 1,2-phenylene dimethyl sulfoxide was 100:1. After thorough mixing, the mixture was coated onto a stainless steel plate and then transferred to water for curing for 60 min. The membrane layer was then removed from the plate to obtain an ion exchange membrane with a thickness of 0.5 μm.

[0049] The mechanical properties, electrical properties, and ion selectivity of the ion exchange membranes in Examples 1-4 and Comparative Examples 1-2 were tested using the following methods:

[0050] A vanadium redox flow battery electrolyte was simulated using an aqueous solution of 1.5 mol / L VOSO4 and 3 mol / L sulfuric acid. The H2O content was measured. + and VO 2+ The ion diffusion coefficient during diffusion and migration through the ion-conducting membrane to the blank side of deionized water is determined using H0. + and VO 2+ The ratio of diffusion coefficients characterizes the ion selectivity of the membrane. (Blank side H) + The change in concentration over time is due to H + VO was measured by a composite electrode. 2+ The change in concentration over time was measured using a UV-Vis spectrophotometer.

[0051] Table 1 Performance test results of different ion exchange membrane samples

[0052]

[0053] As shown in Table 1, the lack of a support layer and the presence of a small amount of residual 1,2-phenylenediamide significantly reduces the ion selectivity of the ion exchange membrane. The ion exchange membrane prepared in this invention exhibits slightly better mechanical and electrical properties than existing ion exchange membranes, while its ion selectivity is significantly higher. Comparative Example 3 demonstrates that directly adding 1,2-phenylenediamide to the ion exchange membrane not only fails to improve its performance but also leads to a significant decrease in ion selectivity.

Claims

1. A method for preparing a perfluorosulfonic acid ion exchange membrane, characterized in that, Includes the following steps: (1) A support layer was prepared using aromatic organic compounds containing amino functional groups; (2) Coating the support layer with perfluorosulfonic acid ion exchange membrane resin, and after curing, forming an ion exchange membrane on the surface of the support layer; (3) Peel the ion exchange membrane off the surface of the support layer; The aromatic organic compounds containing amino functional groups include at least one of 1,2-phenylenediamide, 1,3-phenylenediamide, 1,4-phenylenediamide, and 1,3,5-phenyltricarboxamide.

2. The method for preparing the perfluorosulfonic acid ion exchange membrane according to claim 1, characterized in that, In step (1), the method for preparing the support layer includes the following steps: (11) Dissolve the aromatic organic compound containing the amino functional group in an organic solvent and stir thoroughly to prepare a homogeneous blend solution; (12) Pour the blended solution onto a plate, scrape it flat and evaporate the solvent to obtain the support layer.

3. The method for preparing the perfluorosulfonic acid ion exchange membrane according to claim 2, characterized in that, The organic solvent is at least one of dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone, and N,N-dimethylformamide.

4. The method for preparing the perfluorosulfonic acid ion exchange membrane according to claim 2, characterized in that, In step (11), the molar ratio of the organic solvent to the aromatic organic compound containing the amino functional group is 100:1-100; the stirring conditions are to stir thoroughly at a temperature of 50-60℃ for 12-36h.

5. The method for preparing the perfluorosulfonic acid ion exchange membrane according to claim 2, characterized in that, In step (12), the solvent evaporates for at least 10 seconds.

6. The method for preparing the perfluorosulfonic acid ion exchange membrane according to claim 1, characterized in that, In step (2), the method of coating the support layer with perfluorosulfonic acid ion exchange membrane resin is as follows: immerse the support layer in the perfluorosulfonic acid ion exchange membrane resin solution at 30-50°C for at least 5 seconds and then remove it; the curing method is as follows: transfer the support layer coated with the perfluorosulfonic acid ion exchange membrane resin solution into a poor solvent and cure for at least 30 minutes.

7. The method for preparing the perfluorosulfonic acid ion exchange membrane according to claim 6, characterized in that, The solvent of the perfluorosulfonic acid ion exchange membrane resin solution is at least one of dimethyl sulfoxide, dimethylacetamide, N-methylpyrrolidone, and N,N-dimethylformamide, and the concentration of the solution is 5-60 wt%; the unsuitable solvent is at least one of water, ethanol, isopropanol, or acetone.

8. The method for preparing the perfluorosulfonic acid ion exchange membrane according to claim 7, characterized in that, The concentration of the perfluorosulfonic acid ion exchange membrane resin solution is 10-20 wt%.

9. The method for preparing the perfluorosulfonic acid ion exchange membrane according to claim 1, characterized in that, The thickness of the support layer is at least 10 μm.

10. The application of the perfluorosulfonic acid ion exchange membrane prepared by any one of claims 1-9 in a vanadium redox flow battery.

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