Porous carbon material reinforced ion exchange membrane and preparation method thereof

Abstract

The invention belongs to the technical field of ion exchange membranes, and provides a porous carbon material reinforced ion exchange membrane and a preparation method thereof. The Raman signal spectrum of the porous carbon material enhanced ion exchange membrane has a butadiyne signal peak at 2100 + / -100 cm < 1 >, and the preparation method comprises the following steps: step 1, dissolving ion exchange resin in a solvent, and uniformly stirring; 2, dissolving an organic functional precursor rich in terminal alkyne in the solution in the step 1, and uniformly stirring; 3, adding copper salt into the solution in the step 2, and stirring for reaction to obtain a membrane casting solution; step 4, casting the membrane casting solution into a membrane preparation mold, and carrying out heat treatment to remove the solvent, so as to obtain a membrane material; and 5, carrying out ion exchange on the membrane material to obtain the porous material enhanced ion exchange membrane. The porous carbon material enhanced ion exchange membrane is mild in synthesis condition and simple in process, and the obtained product is high in ionic conductivity, high in mechanical strength, low in swelling property and low in gas permeability.

Description

Technical Field

[0001] This invention relates generally to the field of ion exchange membrane technology, and specifically to an ion exchange membrane reinforced with porous carbon material and its preparation method. Background Technology

[0002] Ion exchange membranes, including anion exchange membranes and cation exchange membranes, are key materials for devices used in water electrolysis for green hydrogen production, fuel cell applications, water treatment, flow batteries, chlor-alkali industry, and high-value carbon dioxide reduction.

[0003] Ultrathin ion exchange membranes are currently a key development direction in the industry. Developing ultrathin, highly stable, high-ion-conductivity, and low-permeability ion exchange membranes can improve the power performance, energy efficiency, and lifespan of devices, while reducing equipment costs. However, the use of ultrathin ion exchange membranes still faces challenges such as poor membrane stability, severe swelling, significant permeation of active substances, and insufficient ion conduction. New concepts are needed to address these issues.

[0004] Improving membrane stability and reducing swelling through cross-linking is a commonly used method. However, current cross-linked membrane preparation methods still face challenges such as poor controllability, complex preparation processes, insufficient membrane lifespan, and severe permeation of active materials. For example, in fuel cells and water electrolysis systems, ultrathin ion exchange membranes struggle to address hydrogen cross-permeation, severely impacting device safety. Similarly, in flow battery systems, cross-permeation of active ions affects energy efficiency and device lifespan.

[0005] By employing solution synthesis methods for porous carbon materials, the excellent mechanical properties and ion-selective transport capabilities of porous carbon materials can be effectively utilized. During the synthesis process, porous carbon materials can undergo excellent physical entanglement with ion-polymers, avoiding sedimentation and achieving uniform dispersion of the porous carbon materials. This also enables efficient physical cross-linking of the porous carbon materials with the ion-polymers. The resulting carbon-rich porous material-reinforced ion exchange membrane exhibits better mechanical properties and active material permeation inhibition, allowing for the development of ion exchange membrane materials with superior mechanical properties, lower swelling, stronger ion conductivity, lower active material permeation, and thinner thickness. Summary of the Invention

[0006] In view of the deficiencies or improvement needs of the existing technology, the present invention aims to provide an ion exchange membrane reinforced with porous carbon materials and its preparation method, which aims to reduce the thickness of the ion exchange membrane, reduce the swelling rate of the membrane, improve the mechanical stability of the membrane, suppress the cross-permeation problem of active materials in the membrane, and obtain a low-cost, high-power, high-efficiency and highly stable ion exchange membrane material.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: The present invention first provides an ion exchange membrane reinforced with porous carbon material, comprising porous carbon material and ion exchange resin. The porous carbon material is formed by a coupling reaction of an organic functional precursor rich in terminal alkynes. The ion exchange resin penetrates the pore structure of the porous carbon material to form a three-dimensional cross-linked network. The Raman signal spectrum of the ion exchange membrane reinforced with porous carbon material is within 2100 ± 100 cm⁻¹. 1 A signal peak for butyryl is observed.

[0008] Another aspect of the present invention provides a method for preparing the above-mentioned porous carbon material-reinforced ion exchange membrane, comprising the following steps: Step 1: Dissolve the ion exchange resin in a solvent and stir until homogeneous to obtain the first solution; Step 2: Dissolve the organic functional precursor rich in terminal alkynes in the first solution and stir until homogeneous to obtain the second solution; Step 3: Add copper salt to the second solution, stir to react, and obtain the casting solution; Step 4: Pour the casting solution into the film forming mold, remove the solvent by heat treatment, and obtain the film material; Step 5: The membrane material is subjected to ion exchange to obtain a porous material-reinforced ion exchange membrane.

[0009] Furthermore, the ion exchange resin in step one is selected from one or more of the following structural formulas and a mixture thereof: , , , , , , , , where m and n are both positive integers, n>20, m≥0.

[0010] Furthermore, the solvent in step one is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, ethylene glycol, ethanol, isopropanol, toluene, xylene, dichlorobenzene, pyridine, tetramethylethylenediamine, and triethylamine. The purpose of step one is to provide a homogeneous polymer solution environment for the subsequent reaction.

[0011] Furthermore, the organic functional precursor of the terminal-rich alkyne in step two is selected from one or more combinations of the following structures: , , , , , , , , , , , , The amount of the organic functional precursor rich in terminal alkyne is 1%-30% of the mass of the ion exchange resin, and the organic functional precursor rich in terminal alkyne serves as the carbon source for porous carbon in the target product.

[0012] Furthermore, the copper salt in step three is selected from one or more of copper acetate, copper chloride, copper acetylacetone, copper sulfate, and copper nitrate; the amount of copper salt added, based on the amount of copper ions, is 20%-100% of the amount of terminal alkyne in the organic functional precursor rich in terminal alkyne; the temperature of the stirring reaction in step three is in the range of 20℃-150℃, and the stirring reaction time is 10 minutes-24 hours, with the copper salt serving as a catalyst for the preparation of terminal alkyne coupling.

[0013] Furthermore, in step four, the heat treatment temperature is 60-180℃, and the heat treatment time is between 10 minutes and 24 hours to evaporate the solvent in the casting solution and enhance the crosslinking effect.

[0014] Furthermore, the ion exchange in step five is carried out in an acidic or alkaline aqueous solution. The acidic aqueous solution is an aqueous solution of sulfuric acid or phosphoric acid, and the alkaline aqueous solution is an aqueous solution of sodium hydroxide or potassium hydroxide. The purpose is to wash away the residual copper salts inside the membrane.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention utilizes a solution synthesis method for porous carbon materials to overcome the bottleneck of dispersed use of porous carbon. It can effectively utilize the excellent mechanical properties and ion selective transport function of porous carbon materials. During the synthesis process, porous carbon materials can undergo good physical entanglement with ion polymers, which not only avoids sedimentation during the synthesis process of porous carbon materials and forms a uniform dispersion of porous carbon materials, but also realizes the efficient physical cross-linking of porous carbon materials with ion polymers.

[0016] 2. The porous material-reinforced ion exchange membrane obtained by the present invention has ion exchange resin penetrating through the pore structure of the porous carbon material to form a three-dimensional cross-linked network. The three-dimensional cross-linking improves the mechanical properties of the membrane and reduces swelling. The porous structure inhibits hydrogen cross-permeation, resulting in better mechanical properties and inhibition of active substance permeation. It is an ion exchange membrane material with better mechanical properties, lower swelling rate, stronger ion conduction, lower active substance permeation, and thinner thickness.

[0017] 3. The method of the present invention can realize the large-scale preparation of ion exchange membranes reinforced with porous carbon materials. The preparation conditions are mild and the process is simple, and it can be applied to a variety of scenarios. Attached Figure Description

[0018] These and / or other aspects and advantages of the present invention will become clearer and more readily understood from the following detailed description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of the porous carbon material-reinforced ion exchange membrane obtained in an embodiment of the present invention; Figure 2 This is a comparison diagram of the mechanical properties of the porous carbon-reinforced sulfonated polyether ether ketone resin membrane and the ion exchange membrane without porous carbon crosslinking obtained in Example 1 of the present invention. Figure 3 An optical photograph of porous carbon-reinforced Nafion obtained in Example 2 of this invention; Figure 4 The image shows the Raman spectrum of porous carbon-reinforced Nafion obtained in Example 2 of this invention. Figure 5 This is a comparison diagram of the gas permeability of the porous carbon-reinforced polyarylene ether sulfone anion exchange resin membrane obtained in Example 3 of the present invention and the ion exchange membrane without porous carbon crosslinking. Figure 6 This is a comparison of the conductivity curves of the porous carbon-reinforced polystyrene anion exchange membrane and the non-porous carbon crosslinked ion exchange membrane obtained in Example 4 of the present invention at different temperatures. Figure 7 This is a comparison chart of the swelling degree of the porous carbon-reinforced ion exchange membrane obtained in Example 5 of the present invention and the ion exchange membrane without porous carbon crosslinking. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0020] Example 1 A porous carbon-reinforced ion exchange membrane is prepared by the following steps: (1) Take 8g of sulfonated polyether ether ketone resin (molecular structure is...) (n>20) is completely dissolved in a mixed solvent of 100 ml dimethyl sulfoxide and 2 ml pyridine; (2) Add 200 mg of hexynylbenzene to the above solution. Mix well; (3) Add 100 mg of copper acetate to the above solution, stir until completely dissolved, and then react the reaction solution at 60 °C for 30 min. (4) The above reaction solution is poured into a film forming mold and dried at 80°C to remove the solvent for 5 hours to obtain the film material. (5) The obtained membrane material was placed in a 0.5 M dilute sulfuric acid solution for ion exchange to obtain a porous carbon-reinforced sulfonated polyether ether ketone proton exchange membrane.

[0021] A schematic diagram of the porous carbon-reinforced sulfonated polyetheretherketone proton exchange membrane obtained in this embodiment is shown below. Figure 1 As shown, the membrane was compared with an ion exchange membrane without porous carbon crosslinking obtained under the same conditions (the only difference being the absence of step two, which involved adding an organic functional precursor rich in terminal alkynes as a carbon source). The mechanical properties of the membrane were tested using a high-low temperature materials testing machine. The sample size used was a 1 cm × 4 cm strip, and the tensile rate was 10 mm / min. -1 ,like Figure 2 As shown, a comparison of the mechanical properties of the porous carbon-reinforced sulfonated polyether ether ketone proton exchange membrane (porous carbon crosslinking) and the ion exchange membrane without porous carbon crosslinking in this embodiment shows that the mechanical properties of the product obtained in this embodiment are significantly improved.

[0022] Example 2 A porous carbon-reinforced ion exchange membrane is prepared by the following steps: (1) Add 4g of Nafion proton exchange resin (molecular formula: (n>20) was dissolved in a mixed solvent of 80 ml N,N-dimethylformamide and 2 ml tetramethylethylenediamine; (2) Add 150 mg of 2,4,6-triethynylaniline to the above solution and stir until homogeneous; (3) Add 100 mg of copper acetate to the above solution, stir until completely dissolved, and then react the reaction solution at 70 degrees for 1 hour; (4) The above reaction solution is poured into a film forming mold and vacuum dried at 70 degrees to remove the solvent for 8 hours to obtain the film material. (5) The obtained membrane material was placed in 500 ml of dilute sulfuric acid solution (1 M) for ion exchange to obtain a porous carbon-reinforced sulfonated polyether ether ketone proton exchange membrane.

[0023] Optical images of porous carbon-reinforced Nafion obtained in this embodiment are shown below. Figure 3 As shown, it can be prepared on a large scale. (As illustrated...) Figure 4 As shown, the Raman signal spectrum of the porous carbon-reinforced Nafion obtained in this embodiment is at 2100±100 cm⁻¹. 1 The presence of a butadiyne signal peak indicates that the product prepared in this embodiment was successful.

[0024] Example 3 A porous carbon-reinforced ion exchange membrane is prepared by the following steps: (1) Dissolve 7g of polyarylethersulfone anion exchange resin 4 completely in a mixed solvent of 120 ml dimethyl sulfoxide and 5 ml pyridine; (2) Add 180 mg of trifluorotriethynylbenzene to the above solution and stir until homogeneous; (3) Add 200 mg of copper acetate to the above solution, stir until completely dissolved, and then react the reaction solution at 40 degrees for 2 hours. (4) The above reaction solution is poured into a film forming mold and dried at 120 degrees to remove the solvent. The drying time is 3 hours to obtain the film material. (5) The obtained membrane material was placed in a 1 M sodium hydroxide solution for ion exchange to obtain a porous carbon-reinforced anion exchange membrane.

[0025] like Figure 5 As shown, the porous carbon-reinforced polyarylene sulfone anion exchange membrane (porous carbon crosslinking) obtained in this embodiment was compared with an ion exchange membrane without porous carbon crosslinking obtained under the same conditions (the only difference being the absence of the addition of a terminal alkyne-rich organic functional precursor as a carbon source in step two) in a gas permeation inhibition test. Specifically, a gas chromatograph (GC) was used to obtain the hydrogen concentration in oxygen (H2 in O2). A mixed gas from the anode of the electrolytic cell was injected into the GC, and the hydrogen concentration was analyzed using a gas chromatograph thermal conductivity detector. The hydrogen content was calculated based on the peak area in the GC spectrum and the working curve. Samples were taken every 5 minutes for testing, and the obtained data were fitted to obtain... Figure 5 As can be seen from the curve, the performance of the product in this embodiment has been significantly improved.

[0026] Example 4 A porous carbon-reinforced ion exchange membrane is prepared by the following steps: (1) Add 12g of polystyrene anion exchange resin (molecular structural formula: (n>20, m>20) is completely dissolved in a mixed solvent of 300 ml N-methylpyrrolidone and 10 ml triethylamine; (2) Add 500 mg of pentaethynylpyridine to the above solution and stir until homogeneous; (3) Add 300 mg of copper acetate to the above solution, stir until completely dissolved, and then react the reaction solution at 90 degrees for 1 hour. (4) The above reaction solution is poured into a film forming mold and dried at 80 degrees to remove the solvent for 10 hours to obtain the film material. (5) The obtained membrane material was placed in 1L of sodium hydroxide solution for ion exchange to obtain a porous carbon-reinforced polystyrene anion exchange membrane.

[0027] like Figure 6 As shown, the conductivity of the porous carbon-reinforced polystyrene anion exchange membrane (porous carbon crosslinking) obtained in this embodiment is compared with that of an ion exchange membrane without porous carbon crosslinking obtained under the same conditions (the only difference being the absence of the addition of a terminal alkyne-rich organic functional precursor as a carbon source in step two). Specifically, the ion resistance of the membrane was obtained using four-probe ESI technology, and then the in-plane conductivity of the membrane was calculated using the formula: (L is the distance between the two electrodes, 3 cm; R is the membrane resistance; W and d are the sample width and thickness, respectively.) The membrane needs to be stabilized for 10 minutes at different temperatures before the membrane resistance can be measured. The obtained data is then fitted to obtain... Figure 6 As can be seen from the curve, the performance of the product in this embodiment has been significantly improved.

[0028] Example 5 An ion exchange membrane reinforced with porous carbon materials, comprising the following steps: (1) Add 6g of anion exchange resin (molecular structural formula: , n is greater than 20, and 6g of cation exchange resin 7 are completely dissolved in a mixed solvent of 500ml N-methylpyrrolidone and 10ml pyridine; (2) Add 200 mg pentaethynylpyridine and 100 mg tetraethynylthiophene to the above solution and stir until homogeneous; (3) Add 200 mg of copper acetate to the above solution, stir until completely dissolved, and then react the reaction solution at 85 degrees for 2 hours. (4) The above reaction solution is poured into a film forming mold and dried at 75 degrees to remove the solvent for 8 hours to obtain the film material. (5) The obtained membrane material is placed in water for ion exchange to obtain a porous carbon-reinforced ion exchange membrane.

[0029] like Figure 7As shown, the swelling degree of the porous carbon-reinforced ion exchange membrane (porous carbon crosslinking) obtained in this embodiment is compared with that of the non-porous carbon crosslinking ion exchange membrane obtained under the same conditions (the only difference being the absence of the addition of a terminal alkyne-rich organic functional precursor as a carbon source in step two). Specifically, vernier calipers were used to measure the membrane's dimensions in dry and wet states. First, the membrane was cut into approximately 1×4 cm strips and placed in a vacuum drying oven to remove moisture. The length and width of the membrane at this point were measured, and the area was recorded as S1. Then, the membrane was immersed in deionized water to completely absorb water, and the length and width of the membrane after water absorption were measured, and the area was recorded as S2. The swelling degree of the membrane was calculated as (S2-S1) / S1. The obtained data were plotted as follows: Figure 7 As can be seen from the bar chart, the performance of the product in this embodiment has been significantly improved.

[0030] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An ion exchange membrane reinforced with porous carbon material, characterized in that, The membrane comprises porous carbon materials and ion exchange resins. The porous carbon materials are formed by a coupling reaction of organic functional precursors rich in terminal alkynes. The ion exchange resins penetrate the pore structure of the porous carbon materials, forming a three-dimensional cross-linked network. The Raman spectrum of the ion exchange membrane enhanced by the porous carbon materials is within 2100 ± 100 cm⁻¹. 1 A signal peak for butyryl is observed.

2. A method for preparing a porous carbon material-reinforced ion exchange membrane as described in claim 1, characterized in that, Includes the following steps: Step 1: Dissolve the ion exchange resin in a solvent and stir until homogeneous to obtain the first solution; Step 2: Dissolve the organic functional precursor rich in terminal alkynes in the first solution, stir until homogeneous, and obtain the second solution; Step 3: Add copper salt to the second solution, stir to react, and obtain the casting solution; Step 4: Cast the casting liquid into the film forming mold, remove the solvent by heat treatment, and obtain the film material; Step 5: The membrane material is subjected to ion exchange to obtain a porous material-reinforced ion exchange membrane.

3. The method for preparing a porous carbon-reinforced ion exchange membrane according to claim 2, characterized in that, The ion exchange resin in step one is one or a mixture of cation exchange resin and anion exchange resin.

4. The method for preparing a porous carbon-reinforced ion exchange membrane according to claim 2, characterized in that: The ion exchange resin used in step one is selected from one or more of the following structural formulas: ， ， ， ， ， ， ， ； Where m and n are both positive integers, n > 20, m ≥ 0.

5. The method for preparing a porous carbon-reinforced ion exchange membrane according to claim 2, characterized in that, The solvent in step one is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, ethylene glycol, ethanol, isopropanol, toluene, xylene, dichlorobenzene, pyridine, tetramethylethylenediamine, and triethylamine.

6. The method for preparing a porous carbon material-reinforced ion exchange membrane according to claim 2, characterized in that, The organic functional precursor rich in terminal alkynes in step two is selected from one or more combinations of the following structures: ， ， ， ， ， ， ， ， ， ， ， ； The amount of the organic functional precursor rich in terminal alkyne added is 1%-30% of the mass of the ion exchange resin.

7. The method for preparing a porous carbon material-reinforced ion exchange membrane according to claim 2, characterized in that, In step three: The copper salt is selected from one or more of copper acetate, copper chloride, copper acetylacetone, copper sulfate, and copper nitrate. The amount of copper salt added, based on the amount of copper ions, is 20%-100% of the amount of terminal alkyne in the organic functional precursor rich in terminal alkyne; The temperature for the stirring reaction is 20℃-150℃, and the stirring reaction time is 10 minutes-24 hours.

8. The method for preparing a porous carbon-reinforced ion exchange membrane according to claim 2, characterized in that, The heat treatment temperature in step four is 60-180℃, and the heat treatment time is between 10 minutes and 24 hours.

9. The method for preparing a porous carbon material-reinforced ion exchange membrane according to claim 2, characterized in that, The ion exchange in step five is carried out in an acidic or alkaline aqueous solution for 1 to 24 hours.

10. The method for preparing a porous carbon-reinforced ion exchange membrane according to claim 9, characterized in that, When ion exchange is carried out in an acidic aqueous solution, the acidic aqueous solution is an aqueous solution of sulfuric acid or phosphoric acid; when ion exchange is carried out in an alkaline aqueous solution, the alkaline aqueous solution is an aqueous solution of sodium hydroxide or potassium hydroxide.

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