High-performance conjugated poly (aryl-piperidine) anion exchange membrane and preparation method thereof

Abstract

The invention discloses a conjugated poly (aryl-piperidine-phenazine) anion exchange membrane for a fuel cell and a preparation method of the conjugated poly (aryl-piperidine-phenazine) anion exchange membrane. Wherein the diaphragm is obtained by carrying out polycondensation on p-terphenyl, phenazine and N-methyl piperidone and then carrying out quaternization. Wherein the ratio of the total mass of the p-terphenyl and the phenazine to the N-methylpiperidone is 1: 1.1. Conjugated monomers are introduced into a polymer skeleton, so that an inter-membrane ion transmission channel is widened, ion transmission is accelerated, and the conductivity of the membrane is improved. The delocalized pi bond structure of phenazine forms compact pi-pi structure accumulation in the polymer membrane, so that the alkali resistance and dimensional stability of the anion exchange membrane are improved. Experimental results show that the OH <-> conductivity of the anion exchange membrane at 80 DEG C is 57.32 mS cm <-1 >-138.04 mS cm <-1 >, and the thickness of the membrane is 22-30 m. And the peak power density can reach 1.06 W cm <-2 >.

Description

Technical Field

[0001] The research field of this invention is polymer chemistry and functional membrane materials, specifically a high-performance conjugated poly (aryl-piperidine) anion exchange membrane and its preparation method. Background Art

[0002] Anion exchange membrane fuel cell (AEMFC) is considered to be an energy conversion device with development potential because it does not require the use of precious metal catalysts and has high energy conversion efficiency. The anion exchange membrane is the core component of AEMFC. It is the isolation barrier between the oxidant and the fuel, and bears the OH - The performance of anion exchange membranes is closely related to the quality of fuel cells. Currently, researchers have shown that the comprehensive performance of existing anion exchange membranes has gradually improved, but there are still deficiencies in commercial applications. This is particularly evident in the low stability in alkaline environments. Therefore, research on the high cost-effectiveness and high stability of anion exchange membranes has become a top priority in this field.

[0003] Achieving OH in AEMs - High transmission and high alkali stability to produce high-performance membrane materials are issues that need to be addressed urgently. The use of ether-free polymers is the preferred way to circumvent the main chain breakage of AEMs. Polyaryl piperidines also greatly reduce the reaction cost because their functional groups are present in the main chain structure. Piperidine cyclic cations are a cationic group with a long half-life, and their special geometric conformation has achieved excellent alkali resistance and stability. In addition, the introduction of conjugated structures effectively broadens the ion transmission channels and produces a stacking structure in the membrane. Therefore, the present invention combines the above advantages to prepare a series of conjugated poly (aryl-piperidine) anion exchange membranes. Summary of the invention

[0004] In order to overcome the current technical difficulties, the present invention aims to provide a conjugated poly (aryl-piperidine) anion exchange membrane that can be used in fuel cells and a preparation method thereof. The present invention obtains a conjugated poly (aryl-piperidine) with excellent performance as a polymer matrix through polycondensation reaction, and then adds iodomethane to continue quaternization reaction as a functional group to prepare an anion exchange membrane. - High transmission and OH realization - The necessary condition for high conductivity is to build a smooth transmission channel in the membrane. The present invention focuses on regulating the polymer electron cloud density through secondary interactions to build an efficient OH - transmission channel, reducing the energy barrier.

[0005] The present invention is achieved through the following technical solutions: The present invention provides a conjugated poly (aryl-piperidine) anion exchange membrane applicable to a fuel cell, wherein the molar ratio of phenazine is 0.05-0.25.

[0006] In the above scheme, the thickness of the diaphragm is 22-30 µm.

[0007] The present invention aims to provide a conjugated poly (aryl-piperidine) anion exchange membrane applicable to a fuel cell and a preparation method thereof, comprising the following steps: Step 1: adding an appropriate amount of functionalized conjugated poly(aryl-piperidine) into a solvent to obtain a casting solution; Step 2: Use the casting solution obtained in step 1 to cast a film to obtain a polymer membrane for use in a fuel cell.

[0008] In the above scheme, the method for preparing the casting solution in step 1 is: The functionalized conjugated poly(aryl-piperidine) is added to a solvent and stirred until completely dissolved to obtain a uniformly dispersed solution. Preferably, the solvent is one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO).

[0009] In the above scheme, the specific operation of step 2 is: The casting liquid was cast on a 5 cm×5 cm clean glass plate and dried in a vacuum oven at 80°C for 24-48 hours. The membrane was placed in a potassium hydroxide solution for 24 hours to remove the membrane, and then the membrane surface was cleaned with deionized water until the cleaning solution became neutral to obtain a conjugated poly (aryl-piperidine) anion exchange membrane for fuel cells.

[0010] In the above scheme, the conjugated poly (aryl-piperidine) polymer is prepared by the following method: Under ice bath conditions, a mol of p-terphenyl, b mol of phenazine and c mol of N-methylpiperidinone are added to a three-necked flask, and then an appropriate amount of solvent and a strong acid catalyst are added to the three-necked flask, followed by mechanical stirring for 5-7 hours. The viscous solution is discharged into ultrapure water to obtain a conjugated poly (aryl-piperidine) polymer, wherein (a+b):c=1:1.1.

[0011] Preferably, the solvent is dichloromethane and the strong acid catalyst is trifluoroacetic acid or trifluoromethanesulfonic acid, and trifluoromethanesulfonic acid is most preferred.

[0012] In the above scheme, the preparation method of the functionalized conjugated poly (aryl-piperidine) is as follows: The preparation method of functionalized conjugated poly (aryl-piperidine) comprises the following steps: Step 1: Place 0.5-1 g of conjugated poly (aryl-piperidine) polymer in 20-25 ml of DMSO solvent and stir magnetically for 10-30 minutes. Then, add a certain amount (500 μL) of iodomethane to the solution and stir the reaction at a certain temperature for 24-48 hours. Pour the solution into ethyl acetate to obtain a white product. Filter the white product and dry it in a vacuum oven (60 ° C, overnight). Obtain a functionalized conjugated poly (aryl-piperidine).

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention first provides a functionalized conjugated poly (aryl-piperidine) anion exchange membrane that can be used in fuel cells. The molar ratio of phenazine is 0.05-0.25. The introduction of conjugated monomers on the main chain is beneficial to changing the electron cloud density of the polymer, constructing a good ion transmission channel, and thus improving the conductivity of the membrane. Phenazine itself has high alkaline stability, so while improving ion conductivity, it also ensures alkaline stability. Experimental results show that the anion exchange membrane of the present invention has an OH of 80 ° C. - Conductivity: 57.32 mS cm -1 -138.04 mS cm -1 , the film thickness is 22-30 µm. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the OH of the anion exchange membrane prepared in Example 1, Example 2, Example 3 and Example 4 of the present invention. - Conductivity variation curve; Figure 2 The battery power density curves of the anion exchange membranes prepared in Examples 2 and 4 of the present invention. Specific implementation methods

[0015] The present invention will be further described below in conjunction with the embodiments. Example

[0016] A conjugated poly (aryl-piperidine) anion exchange membrane applicable to a fuel cell and a preparation method thereof, the specific steps are as follows: (1) At 0°C, 1 mol of p-terphenyl and 1.1 mol of N-methylpiperidone are added to a three-necked flask, and then an appropriate amount of solvent and a strong acid catalyst are added to the three-necked flask, followed by mechanical stirring for 12 hours. The viscous solution is discharged into ultrapure water to obtain poly(aryl-piperidine), wherein the solvent is preferably ethylene dichloride; the strong acid catalyst is preferably trifluoroacetic acid or trifluoromethanesulfonic acid, and trifluoromethanesulfonic acid is most preferably.

[0017] (2) Place 1.0 g of poly(aryl-piperidine) in 20 ml of DMSO solvent and stir magnetically for 10-30 minutes. Then, add 500 μL of iodomethane to the solution and stir at a certain temperature for 24 hours. Pour the solution into ethyl acetate to obtain a white product. Dry in a vacuum oven (60 °C, overnight). Obtain functionalized poly(aryl-piperidine).

[0018] (4) Weigh 0.3 g of the functionalized poly(aryl-piperidine) into a solvent and stir at room temperature for 24 hours to obtain a uniform solution. The preferred solvent includes but is not limited to N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO).

[0019] The casting solution obtained in step (4) was cast onto a 5 cm × 5 cm clean glass plate, placed in an oven at 80 °C and dried for 48 hours, and then cooled to room temperature to form a 1 mol L -1 The membrane was removed in a potassium hydroxide solution and soaked for 24 hours. The membrane surface was then cleaned with deionized water until the cleaning solution was neutral, and a functionalized poly (aryl-piperidine) anion exchange membrane was obtained. The obtained anion exchange membrane was tested at 80 °C, and the conductivity of the membrane was 57.32 mS cm -1 The film thickness is 23 µm and the conductivity is 27.60 mS cm at 30 °C. -1 . Example

[0020] (1) At 0 ° C, 0.95 mol of p-terphenyl, 0.05 mol of phenazine and 1.1 mol of N-methylpiperidone are added to a three-necked flask, and then an appropriate amount of solvent and strong acid catalyst are added to the three-necked flask, and then mechanically stirred for 12 hours. The viscous solution is discharged into ultrapure water to obtain a conjugated poly (aryl-piperidine) polymer, wherein the solvent is preferably ethylene dichloride; the strong acid catalyst is preferably trifluoroacetic acid or trifluoromethanesulfonic acid, and trifluoromethanesulfonic acid is most preferably.

[0021] (2) Place 1.0 g of conjugated poly(aryl-piperidine) polymer in 20 ml of DMSO solvent and stir magnetically for 10-30 minutes. Then, add 500 μL of iodomethane to the solution and stir at a certain temperature for 24 hours. Pour the solution into ethyl acetate to obtain a white product. Dry in a vacuum oven (60 °C, overnight). Obtain a functionalized conjugated poly(aryl-piperidine).

[0022] (4) Weigh 0.3 g of the functionalized conjugated poly(aryl-piperidine) into a solvent and stir at room temperature for 24 hours to obtain a uniform solution. The preferred solvent includes but is not limited to N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO).

[0023] The casting solution obtained in step (4) was cast onto a 5 cm × 5 cm clean glass plate, placed in an 80 °C oven and dried for 48 hours. After cooling naturally to room temperature, 1 mol L -1 The membrane was removed in a potassium hydroxide solution and soaked for 24 hours. The membrane surface was then cleaned with deionized water until the cleaning solution was neutral, and a functionalized conjugated poly (aryl-piperidine) anion exchange membrane was obtained. The obtained anion exchange membrane was tested at 80 °C, and the conductivity of the membrane was 76.73 mS cm -1 The film thickness is 26 µm and the conductivity is 40.75 mS cm at 30 °C. -1 . Example

[0024] (1) At 0°C, 0.85 mol of p-terphenyl, 0.15 mol of phenazine and 1.1 mol of N-methylpiperidone are added to a three-necked flask, and then an appropriate amount of solvent and a strong acid catalyst are added to the three-necked flask, followed by mechanical stirring for 12 hours. The viscous solution is discharged into ultrapure water to obtain a conjugated poly (aryl-piperidine) polymer, wherein the solvent is preferably ethylene dichloride; the strong acid catalyst is preferably trifluoroacetic acid or trifluoromethanesulfonic acid, and trifluoromethanesulfonic acid is most preferably.

[0025] (2) Place 1.0 g of conjugated poly(aryl-piperidine) polymer in 20 ml of DMSO solvent and stir magnetically for 10-30 minutes. Then, add 500 μL of iodomethane to the solution and stir at a certain temperature for 24 hours. Pour the solution into ethyl acetate to obtain a white product. Dry in a vacuum oven (60 °C, overnight). Obtain a functionalized conjugated poly(aryl-piperidine).

[0026] (4) Weigh 0.3 g of the functionalized conjugated poly(aryl-piperidine) into a solvent and stir at room temperature for 24 hours to obtain a uniform solution. The preferred solvent includes but is not limited to N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO).

[0027] The casting solution obtained in step (4) was cast onto a 5 cm × 5 cm clean glass plate, placed in an 80 °C oven and dried for 48 hours. After cooling naturally to room temperature, 1 mol L -1 The membrane was removed in a potassium hydroxide solution and soaked for 24 hours. The membrane surface was then cleaned with deionized water until the cleaning solution was neutral, and a functionalized conjugated poly (aryl-piperidine) anion exchange membrane was obtained. The obtained anion exchange membrane was tested at 80 °C, and the conductivity of the membrane was 83.81 mS cm -1 The film thickness is 30 µm and the conductivity is 45.64 mS cm at 30°C. -1 . Example

[0028] (1) At 0°C, 0.75 mol of p-terphenyl, 0.25 mol of phenazine and 1.1 mol of N-methylpiperidone are added to a three-necked flask, and then an appropriate amount of solvent and a strong acid catalyst are added to the three-necked flask, followed by mechanical stirring for 12 hours. The viscous solution is discharged into ultrapure water to obtain a conjugated poly (aryl-piperidine) polymer, wherein the solvent is preferably ethylene dichloride; the strong acid catalyst is preferably trifluoroacetic acid or trifluoromethanesulfonic acid, and trifluoromethanesulfonic acid is most preferably.

[0029] (2) Place 1.0 g of conjugated poly(aryl-piperidine) polymer in 20 ml of DMSO solvent and stir magnetically for 10-30 minutes. Then, add 500 μL of iodomethane to the solution and stir at a certain temperature for 24 hours. Pour the solution into ethyl acetate to obtain a white product. Dry in a vacuum oven (60 °C, overnight). Obtain a functionalized conjugated poly(aryl-piperidine).

[0030] (4) Weigh 0.3 g of the functionalized conjugated poly(aryl-piperidine) into a solvent and stir at room temperature for 24 hours to obtain a uniform solution. The preferred solvent includes but is not limited to N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO).

[0031] The casting solution obtained in step (4) was cast onto a 5 cm × 5 cm clean glass plate, placed in an 80 °C oven and dried for 48 hours. After cooling naturally to room temperature, 1 mol L -1 The membrane was removed in a potassium hydroxide solution and soaked for 24 hours. The membrane surface was then cleaned with deionized water until the cleaning solution was neutral, and a functionalized conjugated poly (aryl-piperidine) anion exchange membrane was obtained. The obtained anion exchange membrane was tested at 80 °C, and the conductivity of the membrane was 138.04 mS cm -1The film thickness is 22 µm and the conductivity is 78.68 mS cm at 30 °C. -1 .

[0032] Figure 1 The graph is a graph showing the ion conductivity of the membranes prepared in Example 1, Example 2, Example 3 and Example 4 of the present invention as a function of temperature. Among them, the ion conductivity of the membrane prepared in Example 4 is the highest.

[0033] Figure 2 The graph is a battery power density curve of the diaphragms prepared in Example 2 and Example 4 of the present invention. Among them, the ion conductivity of the diaphragm prepared in Example 4 is the highest, which is consistent with the ion conductivity law.

[0034] The description of the above embodiments is only used to help understand the method of the present invention and its core concept. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a polymer membrane for a fuel cell, wherein the membrane is mainly obtained by polymerizing p-terphenyl, phenazine and N-methylpiperidone into a main chain and then functionalizing the main chain; wherein: By adjusting the molar amount of phenazine added, polymer membranes with different phenazine proportions were prepared.

2. According to the method for preparing a polymer membrane for a fuel cell according to claim 1, the molar ratio of the phenazine is 0.05-0.

25.

3. In the polymer membrane for fuel cells according to claim 1, the polymer skeleton is a conjugated poly (aryl-piperidine). The preparation method is as follows: under ice bath conditions, a mol of p-terphenyl, b mol of phenazine and c mol of N-methylpiperidone are added to a three-necked flask, then an appropriate amount of solvent and a strong acid catalyst are added to the three-necked flask, and then mechanically stirred for 12 hours, and the viscous solution is discharged into ultrapure water to obtain a conjugated poly (aryl-piperidine) polymer, wherein: a+b:c=1:1.

1.

4. The method for preparing conjugated poly(aryl-piperidine) according to claim 3, wherein the solvent is dichloromethane and the strong acid catalyst is trifluoroacetic acid or trifluoromethanesulfonic acid.

5. According to claim 1, a method for preparing a polymer membrane for a fuel cell, a method for preparing a functionalized conjugated poly (aryl-piperidine), comprising the following steps: Step 1: Place 0.5 g of conjugated poly (aryl-piperidine) in 20-25 ml of DMSO solvent, stir magnetically for 10-30 minutes, then add a certain amount (500 μL) of iodomethane to the solution, stir and react at a certain temperature for 24-48 hours, pour the solution into ethyl acetate to obtain a white product; filter the white product and dry it in a vacuum oven (60 ° C, overnight). Obtain a functionalized conjugated poly (aryl-piperidine).

6. A method for preparing a polymer membrane for a fuel cell according to claim 1, comprising the following steps: Step 1: adding an appropriate amount of functionalized conjugated poly (aryl-piperidine) to a solvent to obtain a casting solution; Step 2: casting the casting solution obtained in step 1 to obtain a polymer membrane for use in a fuel cell.

7. According to the method for preparing a polymer membrane for a fuel cell according to claim 6, the solvent in step 1 is one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO).

8. The method for preparing a polymer membrane for a fuel cell according to claim 6, characterized in that: The method for preparing the functionalized conjugated poly (aryl-piperidine) casting solution in the above step 1 is: adding the functionalized conjugated poly (aryl-piperidine) into a solvent at room temperature and stirring for 24-48 hours to obtain a uniformly dispersed functionalized conjugated poly (aryl-piperidine) solution.

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