A poly-aniline nanofiber mat reinforced sulfonated poly(ether ether ketone) composite proton exchange membrane, and a preparation method and application thereof

Abstract

The application discloses a kind of polyaniline nanofiber felt reinforced sulfonated polyether ether ketone composite proton exchange membrane and its preparation method and application.Polyaniline nanofiber felt reinforced sulfonated polyether ether ketone composite proton exchange membrane is obtained by polyaniline nanofiber felt being infiltrated and coated with sulfonated polyether ether ketone solution.Preparation method includes the following steps: (1) sulfonated polyether ether ketone powder is dissolved in organic solvent, and sulfonated polyether ether ketone slurry is formed;(2) polyaniline nanofiber felt is prepared;(3) polyaniline nanofiber felt is infiltrated in sulfonated polyether ether ketone slurry, vacuum bubble is discharged after, and is taken out, and heated drying, and modified base cloth is obtained;(4) the sulfonated polyether ether ketone slurry is coated modified base cloth, and polyaniline nanofiber felt reinforced sulfonated polyether ether ketone composite proton exchange membrane is obtained after drying.Proton exchange can be used for hydrogen fuel cell or hydrogen production electrolytic cell diaphragm.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane technology, specifically to a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane, its preparation method, and its application. Background Technology

[0002] With the development of clean energy technologies such as fuel cells, hydrogen energy, and water electrolysis for hydrogen production, the proton exchange membrane (PEM), as a core component of fuel cells, directly determines the overall efficiency and lifespan of the fuel cell. Currently, the most widely used PEMs on the market are mainly represented by perfluorosulfonic acid resins (such as Nafion). However, the high cost of perfluorosulfonic acid resins has always been one of the main factors hindering the commercialization of fuel cells. In recent years, sulfonated polyether ether ketone (SPEEK) has emerged as a low-cost PEM material, achieving high proton conductivity in the hydrated state. However, it also presents some problems. For example, while increasing the degree of sulfonation can enhance proton conductivity, it also increases water absorption. Excessive water absorption and swelling can exacerbate vanadium ion penetration. Conversely, decreasing the degree of sulfonation reduces proton transport sites and lowers proton conductivity. Therefore, how to avoid increasing vanadium ion penetration and reducing mechanical strength due to excessive sulfonation, while simultaneously ensuring the proton conductivity of the SPEEK membrane, has become a pressing technical problem for the industry. Summary of the Invention

[0003] In view of the problems existing in the background art, the purpose of the present invention is to provide a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane. This proton exchange membrane is formed by impregnating the sulfonated polyether ether ketone into the pores of the polyaniline nanofiber felt, forming a composite proton exchange membrane with the polyaniline nanofiber felt as the skeleton and the sulfonated polyether ether ketone as the matrix resin. The amino groups on the surface of the polyaniline nanofibers and the sulfonic acid groups in the sulfonated polyether ether ketone matrix form a strong acid-base electrostatic interaction, resulting in high interfacial bonding. This not only increases the mechanical strength and dimensional stability of the proton exchange membrane, but also does not affect the proton conductivity of the composite membrane and reduces the vanadium ion permeability, thus exhibiting high comprehensive performance.

[0004] To achieve the above objectives, in a first aspect, the present invention provides a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane, which is obtained by impregnating and coating polyaniline nanofiber felt with a sulfonated polyether ether ketone solution.

[0005] Preferably, the polyaniline nanofiber felt has a fiber diameter of 100-200 nm, a pore size of 5-8 μm, and a thickness of 20-30 μm.

[0006] Preferably, the concentration of the sulfonated polyether ether ketone solution is 20-30 wt%.

[0007] Preferably, the thickness of the polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane is 50-70 μm.

[0008] In a second aspect, according to the present invention, a method for preparing a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane includes the following steps: (1) dissolving sulfonated polyether ether ketone powder in an organic solvent to form a sulfonated polyether ether ketone slurry; (2) preparing a polyaniline nanofiber felt; (3) impregnating the polyaniline nanofiber felt in the sulfonated polyether ether ketone slurry, removing it under vacuum after degassing, and heating and drying it to obtain a modified base fabric; (4) coating the modified base fabric with the sulfonated polyether ether ketone slurry, and drying it to obtain a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane.

[0009] Preferably, the method for preparing polyaniline nanofiber felt in step (2) is electrospinning.

[0010] Preferably, the electrospinning process is as follows: (1) preparing a polyaniline spinning solution with a concentration of 5-10wt%; (2) adding the polyaniline spinning solution to an electrospinning device for spinning, and after spinning, removing the resulting fiber mat from the collecting roller and drying it in an oven to remove excess solvent; wherein, the needle tip diameter is 0.5nm, the distance between the needle tip and the collecting roller is 13cm, the spinning voltage is 15kV, and the drying temperature is 100-105℃.

[0011] Preferably, the number of times the immersion and drying in step (3) is 1-5 times; the number of times the coating in step (4) is 1-3 times.

[0012] Thirdly, according to the present invention, a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane is used as a diaphragm in a hydrogen fuel cell or a hydrogen electrolyzer.

[0013] Fourthly, according to the present invention, a hydrogen fuel cell includes the above-mentioned polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane.

[0014] The beneficial effects of this invention are as follows:

[0015] This invention involves impregnating highly sulfonated polyether ether ketone into the pores of polyaniline nanofiber felt to form a composite proton exchange membrane with polyaniline nanofiber felt as the skeleton and highly sulfonated polyether ether ketone as the matrix resin. Due to the strong acid-base electrostatic interaction between the amino groups on the surface of the polyaniline nanofibers and the sulfonic acid groups in the sulfonated polyether ether ketone matrix, the interfacial bonding force is high. This not only increases the mechanical strength and dimensional stability of the proton exchange membrane, but also provides high thermal stability and good durability. Furthermore, it does not affect the proton conductivity of the composite membrane or reduce the vanadium ion permeability, resulting in high overall performance. Detailed Implementation

[0016] To make the above-mentioned objects, features and advantages of the invention more apparent and understandable, the specific embodiments of the invention are described in detail below.

[0017] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0018] First, a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane according to the present invention is described, which is obtained by impregnating and coating polyaniline nanofiber felt with sulfonated polyether ether ketone solution.

[0019] In one embodiment, the polyaniline nanofiber felt has a fiber diameter of 100-200 nm, a pore size of 5-8 μm, and a thickness of 20-30 μm.

[0020] In one embodiment, the sulfonated polyether ether ketone has a sulfonation degree greater than 85%, and the solution concentration of the sulfonated polyether ether ketone is 20-30 wt%.

[0021] In one embodiment, the thickness of the polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane is 50-70 μm.

[0022] Secondly, a method for preparing a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane according to the present invention is described, comprising the following steps: (1) dissolving sulfonated polyether ether ketone powder in an organic solvent to form a sulfonated polyether ether ketone slurry; (2) preparing a polyaniline nanofiber felt; (3) impregnating the polyaniline nanofiber felt in the sulfonated polyether ether ketone slurry, removing it under vacuum after degassing, and heating and drying it to obtain a modified base fabric; (4) coating the modified base fabric with the sulfonated polyether ether ketone slurry, and drying it to obtain a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane.

[0023] In one embodiment, the method for preparing polyaniline nanofiber felt in step (2) is electrospinning.

[0024] In one embodiment, the electrospinning process is as follows: (1) preparing a polyaniline spinning solution with a concentration of 5-10wt%; (2) adding the polyaniline spinning solution to an electrospinning device for spinning, and after spinning, removing the resulting fiber mat from the collecting roller and drying it in an oven to remove excess solvent; wherein, the needle tip diameter is 0.5nm, the distance between the needle tip and the collecting roller is 13cm, the spinning voltage is 15kV, and the drying temperature is 100-105℃.

[0025] In one embodiment, the number of times the wetting and drying in step (3) is 1-5 times; the number of times the coating in step (4) is 1-3 times.

[0026] Furthermore, the application of a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane according to the present invention is explained, for use as a membrane in a hydrogen fuel cell or a hydrogen electrolyzer.

[0027] Finally, a hydrogen fuel cell according to the present invention is described, comprising the above-described polyaniline nanofiber felt reinforced sulfonated polyether ether ketone composite proton exchange membrane.

[0028] The following examples illustrate the products, preparation methods, and applications of the present invention. Main raw materials and equipment used: Unless otherwise specified, the raw materials and equipment used in each example and comparative example are the same; materials not specifically designated are from common, market-purchased models of the same type, and no specific restrictions are imposed. Among them, sulfonated polyether ether ketone was prepared in-house, and the specific preparation method is as follows: (1) Polyether ether ketone powder (Solvay, USA, KT-820UFP), sulfonated graphene (Sichuan Kenye Technology Development Co., Ltd., KYS-GNS) Both FeCl3 and FeCl3 were pre-dried in a vacuum drying oven at 105℃ for 8-12 hours; 400ml of 98wt% concentrated H2SO4 was placed in a 1000ml three-necked flask, the water bath temperature was controlled at 40℃, the PTFE stirring rod was turned on to a speed of 300rpm / min, 40g of polyether ether ketone powder was slowly added until the polyether ether ketone was completely dissolved, 3g of sulfonated graphene and 0.5g of FeCl3 were added, and the mixture was stirred evenly and kept for 2 hours to obtain the sulfonated solution; (2) A mixture of pure ice and water was placed in a beaker to make When the water temperature is below 5°C, use a glass rod to continuously stir the ice-water mixture to form a vortex and slowly pour it into the sulfonated liquid in a linear manner, so that the liquid precipitates the sulfonated polyether ether ketone primary material in the ice-water mixture; (3) Separate the sulfonated polyether ether ketone primary material from the ice-water mixture, and repeatedly soak and wash it three times with dilute hydrochloric acid with a mass concentration of 3%, wash it with deionized water until the pH value reaches 7, drain it and put it into a forced-air drying oven, set the temperature to 60°C, and dry it for 12 hours to obtain sulfonated polyether ether ketone powder with a sulfonation degree of 88.2%.

[0029] The polyaniline is a self-made conductive polyaniline. The specific preparation method is as follows: (1) At room temperature, add 100 parts by weight of dodecylbenzenesulfonic acid (DBSA) and 400 parts by weight of ethanol / water (volume ratio 5:5) mixed solvent to the reaction vessel and stir evenly to obtain DBSA solution; (2) Add 25 parts by weight of aniline to DBSA solution dropwise, stir evenly, and then gradually add 120 parts by weight of 50wt% ammonium persulfate solution while maintaining stirring. After reacting for 7 hours, a dark green product solution is obtained; (3) Add excess methanol to demulsify, centrifuge, wash the solid with deionized water until neutral, and dry to obtain polyaniline.

[0030] Example 1

[0031] 1. Sulfonated polyether ether ketone powder is dissolved in DMF to form a sulfonated polyether ether ketone slurry with a concentration of 20wt%;

[0032] 2. Preparation of polyaniline nanofiber felt by electrospinning, wherein the electrospinning process is as follows: (1) preparing a polyaniline / DMF spinning solution with a concentration of 5wt%; (2) adding the polyaniline spinning solution to an electrospinning device for spinning, and after spinning, removing the obtained fiber felt from the collecting roller and drying it in an oven to remove excess solvent; wherein the needle tip diameter is 0.5nm, the distance between the needle tip and the collecting roller is 13cm, the spinning voltage is 15kV, and the drying temperature is 100℃; the fiber diameter of the polyaniline nanofiber felt is 100nm, the pore size is 5-8μm, and the thickness is 20±1μm;

[0033] 3. The polyaniline nanofiber felt was impregnated in sulfonated polyether ether ketone slurry for 2 hours, removed under vacuum after degassing, and dried at 100°C for 1 hour to obtain the modified base fabric; the impregnation and drying were repeated 3 times.

[0034] 4. The sulfonated polyether ether ketone slurry is coated onto the modified base fabric three times, and then placed in a vacuum drying oven to dry to constant weight at a temperature of 120°C, a vacuum degree of 0.1 MPa, and a drying time of 24 h. After restoring to normal pressure and cooling to room temperature, it is taken out to obtain a polyaniline nanofiber felt reinforced sulfonated polyether ether ketone composite proton exchange membrane with a thickness of 70±1 μm.

[0035] Example 2

[0036] 1. Sulfonated polyether ether ketone powder is dissolved in DMF to form a sulfonated polyether ether ketone slurry with a concentration of 30wt%;

[0037] 2. Preparation of polyaniline nanofiber felt by electrospinning, wherein the electrospinning process is as follows: (1) preparing a polyaniline / DMF spinning solution with a concentration of 10wt%; (2) adding the polyaniline spinning solution to an electrospinning device for spinning, and after spinning, removing the obtained fiber felt from the collecting roller and drying it in an oven to remove excess solvent; wherein the needle tip diameter is 0.5nm, the distance between the needle tip and the collecting roller is 13cm, the spinning voltage is 15kV, and the drying temperature is 105℃; the fiber diameter of the polyaniline nanofiber felt is 200nm, the pore size range is 5-8μm, and the thickness is 30±1μm;

[0038] 3. The polyaniline nanofiber felt was impregnated in sulfonated polyether ether ketone slurry for 2 hours, removed under vacuum after degassing, and dried at 100°C for 1 hour to obtain the modified base fabric; the impregnation and drying were repeated twice.

[0039] 4. The sulfonated polyether ether ketone slurry is coated onto the modified base fabric twice, and then placed in a vacuum drying oven to dry to constant weight. The drying temperature is 120℃, the vacuum degree is 0.1MPa, and the drying time is 24h. After restoring to normal pressure and cooling to room temperature, it is taken out to obtain a polyaniline nanofiber felt reinforced sulfonated polyether ether ketone composite proton exchange membrane with a thickness of 50±1μm.

[0040] Example 3

[0041] 1. Sulfonated polyether ether ketone powder is dissolved in DMF to form a sulfonated polyether ether ketone slurry with a concentration of 25 wt%;

[0042] 2. Preparation of polyaniline nanofiber felt by electrospinning, wherein the electrospinning process is as follows: (1) preparing a polyaniline / DMF spinning solution with a concentration of 8.5wt%; (2) adding the polyaniline spinning solution to an electrospinning device for spinning, and after spinning, removing the obtained fiber felt from the collecting roller and drying it in an oven to remove excess solvent; wherein the needle tip diameter is 0.5nm, the distance between the needle tip and the collecting roller is 13cm, the spinning voltage is 15kV, and the drying temperature is 102℃; the fiber diameter of the polyaniline nanofiber felt is 120nm, the pore size range is 6-7μm, and the thickness is 25±1μm;

[0043] 3. The polyaniline nanofiber felt was impregnated in sulfonated polyether ether ketone slurry for 2 hours, removed under vacuum after degassing, and dried at 100°C for 1 hour to obtain the modified base fabric; the impregnation and drying were repeated 3 times.

[0044] 4. The sulfonated polyether ether ketone slurry is coated onto the modified base fabric twice, and then placed in a vacuum drying oven to dry to constant weight. The drying temperature is 120℃, the vacuum degree is 0.1MPa, and the drying time is 24h. After restoring to normal pressure and cooling to room temperature, it is taken out to obtain a polyaniline nanofiber felt reinforced sulfonated polyether ether ketone composite proton exchange membrane with a thickness of 60±1μm.

[0045] Comparative Example 1

[0046] 1. Sulfonated polyether ether ketone powder is dissolved in DMF to form a sulfonated polyether ether ketone slurry with a concentration of 25 wt%;

[0047] 2. The sulfonated polyether ether ketone slurry is coated onto a glass substrate and then placed in a vacuum drying oven to dry to constant weight. The drying temperature is 120℃, the vacuum degree is 0.1MPa, and the drying time is 24h. After restoring to normal pressure and cooling to room temperature, it is taken out and peeled off to obtain a modified sulfonated polyether ether ketone proton exchange membrane with a thickness of 60±1μm.

[0048] Performance testing

[0049] 1. Swelling rate and water absorption rate: The swelling rate and water absorption rate (25℃) of the proton exchange membrane are the percentage changes in length and mass of the membrane in the wet state relative to the dry state. The dry state is the initial state, and the wet state is the state of the membrane after being immersed in deionized water at room temperature for 24 hours.

[0050] 2. Mechanical strength: At room temperature, dumbbell-shaped specimen, 10mm wide and 35mm long, tensile speed of universal testing machine is 5mm / min.

[0051] 3. Proton transfer rate: Using the Solatron 1260 electrochemical workstation, with a frequency range of 0.1 Hz to 1 MHz and a voltage amplitude of 10 mV, the proton transfer rate ρ = distance D between the working electrode and the counter electrode / (membrane impedance R × effective membrane area S × 10⁻⁶). 7 ).

[0052] 4. Vanadium ion permeability: H-type diffusion cell (effective area 1.77 cm²) 2 The diffusion cell contained 50 mL of 1.5 M MgSO4 / 3.0 M H2SO4 solution on one side and the same volume of 1.5 M MgSO4 / 3.0 M H2SO4 solution on the other side. Samples were taken from the MgSO4 / H2SO4 solution every 24 hours, and the absorbance was measured at 762 nm using a UV-Vis spectrophotometer. VO2+ was determined using a standard absorbance / concentration curve. 2+ The concentration of vanadium is used to calculate the vanadium permeation rate according to standards.

[0053] The test results are shown in Table 1.

[0054] Table 1

[0055]

[0056] As can be seen from the examples and comparative data, the present invention impregnates the pores of polyaniline nanofiber felt with high-sulfonation degree sulfonated polyether ether ketone, forming a composite proton exchange membrane with polyaniline nanofiber felt as the skeleton and high-sulfonation degree sulfonated polyether ether ketone as the matrix resin. The amino groups on the surface of the polyaniline nanofibers form a strong acid-base electrostatic interaction with the sulfonic acid groups in the sulfonated polyether ether ketone matrix, resulting in high interfacial bonding. This not only increases the mechanical strength and dimensional stability of the proton exchange membrane, but also does not affect the proton conductivity of the composite membrane and reduces the vanadium ion permeability, thus exhibiting high comprehensive performance.

[0057] The above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A polyaniline nanofiber felt-reinforced sulfonated polyetheretherketone composite proton exchange membrane, characterized in that, It is obtained by impregnating and coating polyaniline nanofiber mat with sulfonated polyether ether ketone solution; The polyaniline nanofiber felt has a fiber diameter of 100-200 nm, a pore size of 5-8 μm, and a thickness of 20-30 μm. The concentration of the sulfonated polyether ether ketone solution is 20-30 wt%; the degree of sulfonation of the sulfonated polyether ether ketone is greater than 85%.

2. The polyaniline nanofiber felt-reinforced sulfonated polyetheretherketone composite proton exchange membrane as described in claim 1, characterized in that, The thickness of the polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane is 50-70 μm.

3. The method for preparing the polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane according to any one of claims 1-2, characterized in that, Includes the following steps: (1) Sulfonated polyether ether ketone powder is dissolved in an organic solvent to form sulfonated polyether ether ketone slurry; (2) Preparation of polyaniline nanofiber mat; (3) The polyaniline nanofiber felt was impregnated in sulfonated polyether ether ketone slurry, vacuum defoamed and then removed, heated and dried to obtain the modified base fabric; (4) The sulfonated polyether ether ketone slurry is coated onto the modified base fabric and dried to obtain a polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane.

4. The preparation method according to claim 3, characterized in that, The method for preparing polyaniline nanofiber felt in step (2) is electrospinning.

5. The preparation method according to claim 4, characterized in that, The electrospinning process is as follows: (1) Prepare a polyaniline spinning solution with a concentration of 5-10wt%; (2) Add the polyaniline spinning solution to the electrospinning equipment for spinning. After spinning, remove the obtained fiber mat from the collecting roller and dry it in an oven to remove excess solvent. The needle tip diameter is 0.5nm, the distance between the needle tip and the collecting roller is 13cm, the spinning voltage is 15kV, and the drying temperature is 100-105℃.

6. The preparation method according to claim 3, characterized in that, The number of times of soaking and drying in step (3) is 1-5; the number of times of coating in step (4) is 1-3.

7. The application of the polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane according to any one of claims 1-2 or the polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane obtained by the preparation method according to any one of claims 3-6, characterized in that, Membranes used in hydrogen fuel cells or hydrogen electrolyzers.

8. A hydrogen fuel cell, characterized in that, This includes the polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane as described in any one of claims 1-2, or the polyaniline nanofiber felt-reinforced sulfonated polyether ether ketone composite proton exchange membrane obtained by the preparation method described in any one of claims 3-6.

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