阅读说明：本技术 一种高温质子交换膜的制备方法 (Preparation method of high-temperature proton exchange membrane ) 是由 吕丽芳 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种高温质子交换膜的制备方法,包括以下步骤：步骤一、石英基板修饰；步骤二、纳米SiO<Sub>2</Sub>负载；步骤三、反应液的配制；步骤四、高温质子交换膜的制备。本发明还提供了该方法制备得到的高温质子交换膜及其在燃料电池中的应用。本发明将引发剂修饰在石英基板上,然后进行纳米SiO<Sub>2</Sub>负载,提升膜的综合性能和低湿条件下的质子传导性能,之后再进行原子转移自由基聚合,同时2-(3-吡啶基)苯并咪唑中的吡啶基作为配位基团参与反应,从而构筑了更加有序的质子传输通道,制得的高温质子交换膜具有良好的高温电导率和较低的溶胀率,能够同时适用于高温水合状态和高温低湿状态下的质子传导。(The invention discloses a preparation method of a high-temperature proton exchange membrane, which comprises the following steps: step one, quartz substrate modification; step two, nano SiO 2 A load; step three, preparing reaction liquid; step four, preparing the high-temperature proton exchange membrane. The invention also provides the high-temperature proton exchange membrane prepared by the method and application thereof in a fuel cell. The invention modifies the initiator on the quartz substrate, and then carries out nano SiO 2 Loading, raising comprehensive performance of membrane and proton conducting performance under low humidity condition, atom transfer free radical polymerization, and reaction with pyridyl radical of 2- (3-pyridyl) benzimidazole as coordinating radical to constitute ordered matterThe proton transfer channel and the prepared high-temperature proton exchange membrane have good high-temperature conductivity and lower swelling ratio, and can be simultaneously suitable for proton conduction in a high-temperature hydration state and a high-temperature low-humidity state.)

1. A preparation method of a high-temperature proton exchange membrane is characterized by comprising the following steps:

step one, quartz substrate modification: carrying out hydrophilic treatment on the quartz substrate, and then modifying the quartz substrate by using a silanized initiator to obtain the quartz substrate modified with the initiator;

step two, nano SiO₂Loading: placing a quartz substrate modified with an initiator on a chassis of a vacuum sputtering coating instrument, and adopting SiO₂Sputtering ceramic as target material in argon atmosphere;

step three, preparation of reaction liquid: adding a PAMPS monomer into a polar organic solvent, stirring for dissolving, then sequentially adding a cross-linking agent, a catalyst and a coordination agent, filling nitrogen for removing oxygen, and stirring to obtain a reaction solution;

step four, preparing a high-temperature proton exchange membrane: and (3) forming a film on the surface of the quartz substrate by the reaction liquid prepared in the third step in a casting or spin coating mode, filling nitrogen to remove oxygen, carrying out oil bath reaction at 70 ℃ in nitrogen atmosphere, taking out and cleaning the quartz substrate after the reaction is finished, removing the film from the sulfuric acid solution, washing with deionized water, and carrying out vacuum drying to obtain the high-temperature proton exchange membrane.

2. The method for preparing a high temperature proton exchange membrane according to claim 1, wherein the silylation initiator in the first step is prepared by reacting 3-aminopropyltriethoxysilane with 2-bromoisobutyryl bromide, and has a structural formula of

3. A process for preparing a high temperature proton exchange membrane as claimed in claim 1 wherein the SiO used in step two₂The ceramic target is high-purity high-density silicon dioxide, and the purity is more than 99.99 percent.

4. The method for preparing a high-temperature proton exchange membrane according to claim 1, wherein in the second step, the vertical distance between the target and the base plate is 10-12 cm, the sputtering power is 80-100W, and the sputtering time is 5-15 s.

5. A method for preparing a high temperature proton exchange membrane according to claim 1, wherein the polar organic solvent in step three is one or more of N, N-Dimethylformamide (DMF), N-Dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), acetone, or butanone.

6. A method for preparing a high temperature proton exchange membrane according to claim 1 wherein in step three the cross-linking agent is N, N-Methylene Bis Acrylamide (MBA) and is used in an amount of 1% to 4% by mass of PAMPS monomer.

7. A method for preparing a high-temperature proton exchange membrane according to claim 1, wherein the catalyst in step three is cuprous bromide or cuprous chloride, and the amount of the catalyst is 5-10% of the mass of the PAMPS monomer.

8. A method for preparing a high temperature proton exchange membrane according to claim 1 wherein in step three the complexing agent is 2- (3-pyridyl) benzimidazole in an amount of 5% to 10% by weight of the PAMPS monomer.

9. A high temperature proton exchange membrane prepared by the method of any one of claims 1 to 8.

10. Use of a high temperature proton exchange membrane according to claim 9 in a fuel cell.

Technical Field

The invention relates to the technical field of fuel cells, in particular to a preparation method of a high-temperature proton exchange membrane.

Background

The conventional PEMFC proton exchange membrane is formed by widely adopting perfluorinated sulfonic acid resin, the proton conductivity of the membrane depends heavily on liquid water, the PEM is dehydrated generally when the PEMFC proton exchange membrane works at 60-90 ℃, the proton conductivity is reduced sharply, and the performance of the cell is seriously attenuated. Therefore, developing a high temperature resistant proton exchange membrane fuel cell, and increasing the operating temperature of the PEMFC is one of effective measures for solving the problems of poor environmental tolerance, performance attenuation and the like of the traditional PEMFC.

Therefore, the research and development of the proton exchange membrane which can be simultaneously suitable for the hydration state and the high-temperature low-humidity condition, has good mechanical property and high proton conductivity has very important significance.

Disclosure of Invention

Aiming at the defects of the existing proton exchange membrane, the invention provides a preparation method of a high-temperature proton exchange membrane with low swelling ratio, high proton conductivity and good mechanical strength.

The purpose of the invention is realized by the following technical scheme:

a preparation method of a high-temperature proton exchange membrane comprises the following steps:

step one, quartz substrate modification: carrying out hydrophilic treatment on the quartz substrate, and then modifying the quartz substrate by using a silanized initiator to obtain the quartz substrate modified with the initiator;

step two, nano SiO₂Loading: placing a quartz substrate modified with an initiator on a chassis of a vacuum sputtering coating instrument, and adopting SiO₂Sputtering ceramic as target material in argon atmosphere;

step three, preparation of reaction liquid: adding a PAMPS monomer into a polar organic solvent, stirring for dissolving, then sequentially adding a cross-linking agent, a catalyst and a coordination agent, filling nitrogen for removing oxygen, and stirring to obtain a reaction solution;

step four, preparing a high-temperature proton exchange membrane: and (3) forming a film on the surface of the quartz substrate by the reaction liquid prepared in the third step in a casting or spin coating mode, filling nitrogen to remove oxygen, carrying out oil bath reaction at 70 ℃ in nitrogen atmosphere, taking out and cleaning the quartz substrate after the reaction is finished, removing the film from the sulfuric acid solution, washing with deionized water, and carrying out vacuum drying to obtain the high-temperature proton exchange membrane.

Further, in the first step, the quartz substrate is subjected to hydrophilic treatment by using water and salicylic acid, namely mixed solution of concentrated sulfuric acid and hydrogen peroxide in a volume ratio of 2: 1.

Further, in the step one, the silanized initiator is prepared by the reaction of 3-aminopropyl triethoxysilane and 2-bromoisobutyryl bromide, and the structural formula is

Further, SiO used in the second step₂The ceramic target is high-purity high-density silicon dioxide with the purity of more than 99.99 percent。

Furthermore, in the second step, the vertical distance between the target and the base plate is 10-12 cm, the sputtering power is 80-100W, and the sputtering time is 5-15 s.

Further, in the third step, the polar organic solvent is one or more of N, N-Dimethylformamide (DMF), N-Dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), acetone, or butanone.

Further, in the third step, the cross-linking agent is N, N-Methylene Bisacrylamide (MBA), and the using amount of the cross-linking agent is 1-4% of the mass of the PAMPS monomer.

Further, the catalyst in the third step is cuprous bromide or cuprous chloride, and the using amount of the catalyst is 5-10% of the mass of the PAMPS monomer.

Furthermore, in the third step, the complexing agent is 2- (3-pyridyl) benzimidazole, and the using amount of the complexing agent is 5-10% of the mass of the PAMPS monomer.

Further, after nitrogen is filled in the third step to remove oxygen, stirring is carried out for 0.5h at room temperature, so that the catalyst and the complexing agent are fully coordinated.

Further, the specific operations of cleaning the quartz substrate in the fourth step are as follows: the quartz substrate was rinsed with water, methanol, and dichloromethane, respectively.

The invention also aims to provide the high-temperature proton exchange membrane prepared by the preparation method.

The invention also provides the application of the high-temperature proton exchange membrane prepared by the preparation method in a fuel cell.

The poly-2-acrylamide-2-methylpropanesulfonic acid (PAMPS) used in the invention is polyelectrolyte containing strong anionic sulfonic acid groups, has small EW value and excellent proton conductivity, and has good acid resistance and thermal stability due to the amide groups which have shielding effect on molecular chains. The invention adopts a crosslinking modification method, and increases the mechanical strength and the stability of physical dimension by addition crosslinking, so that the invention can be suitable for the working environment of a high-temperature fuel cell.

The invention forms orderly arranged initiation by loading the initiation agent on the quartz substrateA monomolecular layer is added, and then nano SiO is loaded on the substrate through vacuum sputtering₂The nano SiO is controlled by adjusting the sputtering time₂The load capacity of the nano-powder is adjusted by sputtering power and the distance between the target and the chassis, the sputtered nano-particles are endowed with certain kinetic energy, and the flexible chain of the silanized initiator plays a role in buffering, so that the nano-SiO with relatively larger particle size₂The particles are blocked in the molecular gaps of the initiator, so that active groups of the initiator cannot be covered, and SiO can be avoided₂The particles are gathered or deposited on a quartz substrate, then a polymerization reaction liquid is formed into a film on the surface of the substrate in a casting or spin coating mode, a PAMPS monomer and a complexing agent 2- (3-pyridyl) benzimidazole are taken as polymerization units, MBA is taken as a cross-linking agent, and the cross-linked modified PAMPS high-temperature proton exchange membrane is prepared in an atom transfer radical polymerization mode.

The water contact angle tester is used for monitoring the surface hydrophilicity of the quartz substrate in the preparation process, and the result shows that: the water contact angle of the quartz substrate after hydrophilic treatment is only 2-5 degrees, the contact angle of the quartz substrate modified with the initiator is increased to 85-89 degrees, and the reason is that bromine atoms on the initiator are exposed on the outermost layer and are groups with strong hydrophobicity, so that the water contact angle is increased. And nano SiO₂After loading, the hydrophilicity of the surface of the substrate is increased, the contact angle is reduced to 27-29 degrees, the contact angle after the polymerization reaction is finished is 69-72 degrees, and the hydrophobicity of the crosslinked PAMPS is enhanced.

The surface roughness of the quartz substrate in the preparation process is monitored by an atomic force microscope, and the result shows that: the quartz substrate after hydrophilic treatment has extremely small surface roughness, Ra is 0.26nm, and nano SiO is loaded in a sputtering way₂The roughness after polymerization was further reduced by increasing the roughness, Ra 38.4nm, and Ra 32.5nm, because the order of the polymer structure makes the surface structure of the film regular and thus has a low roughness even though it is a porous film.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention modifies the initiator on the quartz substrate, and then carries out nano SiO₂Loaded, nano-SiO₂Is advantageous for increasingThe mechanical strength and the dimensional stability of the added membrane improve the comprehensive performance of the membrane and the proton conduction performance under a low-humidity condition, then atom transfer radical polymerization is carried out, the order arrangement of initiator molecules and the operation of firstly forming a reaction liquid and then carrying out polymerization reaction can ensure the order of the membrane structure, and meanwhile, the pyridyl in the 2- (3-pyridyl) benzimidazole is taken as a coordination group to participate in the reaction, so that the polymerization product has better stereoregularity, a more ordered proton transmission channel is constructed, and the proton transmission efficiency is improved;

(2) in the invention, the PAMPS forms a cross-linking modified PAMPS film through cross-linking and coordination polymerization, and the addition reaction of double C ═ C bonds of MBA forms cross-linking among polymer chains, and the cross-linking can also form cross-linking with nano SiO₂The mechanical property of the proton exchange membrane is further improved, and the prepared high-temperature proton exchange membrane has excellent comprehensive performance, good high-temperature conductivity and lower swelling ratio, and can be simultaneously suitable for proton conduction in a high-temperature hydration state and a high-temperature low-humidity state.

Detailed Description

To further illustrate the technical means and effects of the present invention, the following detailed description is given with reference to specific embodiments.