PEM water electrolysis proton exchange membrane and preparation method thereof

Abstract

The invention discloses a PEM proton exchange membrane for water electrolysis and a preparation method thereof, and relates to the technical field of water electrolysis. The proton exchange membrane is composed of five layers of structures including a modified sulfonated composite resin layer, an enhancement layer, a water retention layer, a catalyst layer and an anti-permeation layer, the preparation method comprises the following steps: the modified sulfonated composite resin layer is prepared by dispersing perfluorinated sulfonic acid resin and sulfonated lignin in a solvent, coating and drying; the reinforcing layer is prepared by blending a PTFE (Polytetrafluoroethylene) emulsion, a carbon nanotube and a tetrafluoroethylene-hexafluoropropylene copolymer, and then carrying out casting sintering, plasma treatment and hot press molding; the water retention layer is prepared by adopting an electrostatic spinning technology; the catalyst layer is formed by spraying a precursor solution step by step and drying; the anti-permeation layer is prepared through photoetching-etching array construction, resin coating and fluorosilane modification. The prepared proton exchange membrane has excellent mechanical strength, proton conductivity and stability, and is suitable for the field of PEM water electrolysis.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of water electrolysis, in particular to a proton exchange membrane for PEM water electrolysis and a preparation method thereof. BACKGROUND

[0002] In the process of global energy structure transformation towards clean and low-carbon, hydrogen energy as a zero-carbon energy carrier, its efficient preparation technology has become a research hotspot. PEM (Proton Exchange Membrane) water electrolysis hydrogen production technology is considered as one of the core technologies for green hydrogen production due to its rapid start-up, high gas purity and low energy consumption. As a key component of PEM electrolyzer, the proton exchange membrane plays a key role in proton conduction, gas separation and mechanical support, and its performance directly determines the efficiency, stability and service life of the electrolyzer.

[0003] In the prior art, the traditional proton exchange membrane has many bottlenecks: first, the mechanical strength is insufficient, and swelling, cracking or interlayer peeling easily occurs under long-term high-temperature and high-pressure operating conditions, resulting in shortened membrane life; second, the water retention capacity is limited, and the proton conduction channel is easily interrupted under high-temperature and low-humidity conditions, causing a significant decrease in proton conductivity; third, the interface bonding force between the catalyst layer and the membrane is weak, the catalyst is easy to fall off and lacks a self-repairing mechanism, and the catalytic activity decays quickly; and fourth, the gas barrier performance is poor, and the cross-penetration of hydrogen and oxygen not only reduces the gas purity, but also has safety hazards.

[0004] Therefore, it is necessary to develop a proton exchange membrane with high mechanical strength, high proton conductivity, excellent water retention, stable catalytic performance and good gas barrier performance, which is the key to promoting the industrial application of PEM water electrolysis hydrogen production technology. SUMMARY

[0005] The purpose of the present application is to provide a proton exchange membrane for PEM water electrolysis and a preparation method thereof to solve the problems in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: A proton exchange membrane for PEM water electrolysis, which is composed of five layers, including a modified sulfonated composite resin layer, a reinforcing layer, a water retention layer, a catalyst layer and a permeation prevention layer.

[0007] A preparation method of a proton exchange membrane for PEM water electrolysis, comprising the following steps: (1) Preparing the modified sulfonated composite resin layer: dispersing perfluorosulfonic acid resin and sulfonated lignin in a solvent, ultrasonic dispersion, coating on the surface of a release film, drying to obtain the modified sulfonated composite resin layer; (2) Preparing the reinforcing layer: blending PTFE emulsion, carbon nanotubes and tetrafluoroethylene-hexafluoropropylene copolymer, flow casting and sintering, then performing plasma treatment to obtain the reinforcing layer, and then hot pressing and bonding with the modified sulfonated composite resin layer; (3) Preparing water-retention layer: using electrospinning technology, spin sulfonated poly (arylene ether ketone) solution on the surface of the reinforced layer, dry at 70-80℃ for 20-25min, forming water-retention layer; (4) Preparing catalyst layer: spray transition metal oxide precursor solution on the surface of the water-retention layer, after drying, spray noble metal precursor solution, dry at 65-75℃ for 15-20min, forming catalyst layer; (5) Preparing impermeable layer: construct pyramid array on the surface of the catalyst layer by photoetching method; coat perfluorosulfonic acid resin, then modify by fluorosilane vapor deposition, dry at 110-120℃ for 60-90min in nitrogen atmosphere, peel off release film, then the proton exchange membrane is obtained.

[0008] Further, in step (1), the solvent is one of N,N-dimethylformamide, N-methyl pyrrolidone, dimethyl sulfoxide; The mass ratio of perfluorosulfonic acid resin, sulfonated lignin, solvent is (7-8):(2-3):(40-60); The process conditions of ultrasonic dispersion are: ultrasonic power 300-400W, time 30-60min; The process conditions of drying are: temperature 50-60℃, time 15-20min.

[0009] Further, in step (2), the mass ratio of PTFE emulsion, carbon nanotube, tetrafluoroethylene-hexafluoropropylene copolymer is (75-80):(2-4):(8-15); The solid content of PTFE (polytetrafluoroethylene) emulsion is 50-60%, and the solvent is water; The process conditions of casting and sintering are: casting speed 0.5-1.5m / min, scraper gap 50-80μm, sintering temperature 350-380℃, sintering time 30-40min; The process conditions of plasma treatment are: Ar / O2 mixed gas flow 20-50sccm, volume ratio of Ar and O2 (4-4.5):1, power 120-150W, time 5-8min; The process conditions of hot pressing are: temperature 80-120℃, pressure 0.2-0.3MPa, time 8-12min.

[0010] Further, in step (3), the solid content of sulfonated poly (arylene ether ketone) solution is 15-20%, and the solvent is one of N,N-dimethylformamide, N-methyl pyrrolidone, dimethyl sulfoxide; The process conditions of electrospinning technology are: spinning voltage 12-18kV, receiving distance 15-20cm, pushing rate 0.5-1.0mL / h.

[0011] Further, in step (4), the transition metal oxide precursor solution comprises the following mass components: 0.5-0.8 parts of chloroiridic acid solution, 2-3 parts of citric acid, 10-15 parts of perfluorosulfonic acid resin solution, 30-35 parts of anhydrous ethanol, 46.2-57.5 parts of deionized water; The noble metal precursor solution comprises the following mass components: 0.3-0.5 parts of chloroplatinic acid solution, 15-20 parts of perfluorosulfonic acid resin solution, 0.1-0.3 parts of sodium dodecyl sulfate, 30-35 parts of ethylene glycol, 44.2-54.6 parts of deionized water; The chloroiridic acid solution has a concentration of 0.1-1% and an anhydrous ethanol solvent; The chloroplatinic acid solution has a concentration of 0.1-1% and an anhydrous ethanol solvent.

[0012] Further, in step (5), the height of the pyramid array is 4-6 μm, and the pitch is 8-12 μm; The process conditions of the photolithography-etching method are as follows: photolithography exposure wavelength 365 nm, photolithography energy 100-200 mJ / cm 2 , photolithography time 10-20 s, etching gas CF4 gas, etching power 180-200 W, and etching time 5-8 min; The process conditions of the fluorosilane vapor deposition are as follows: temperature 80-100℃, and time 30-40 min.

[0013] Further, the thickness of the modified sulfonated composite resin layer is 20-25 μm; the thickness of the reinforcing layer is 3-5 μm; the thickness of the water-retaining layer is 18-22 μm; the thickness of the catalyst layer is 0.4-0.7 μm; and the thickness of the anti-permeation layer is 0.8-1.2 μm.

[0014] Compared with the prior art, the present application has the following beneficial effects: 1、The PEM water electrolysis proton exchange membrane and the preparation method thereof described in the present application, the reinforcing layer of the proton exchange membrane is prepared by blending PTFE emulsion, carbon nanotubes and tetrafluoroethylene-hexafluoropropylene copolymer, and the key process for preparing the reinforcing layer is flow casting and sintering, the coating thickness can be accurately controlled by controlling the flow casting speed and the scraper gap, which lays a foundation for the interlayer bonding and the overall membrane performance stability; sintering at 350-380℃ can make the polymers in the blending system fully melt, crosslink and remove the solvent, form a dense and stable polymer network structure, improve the mechanical strength and chemical resistance of the reinforcing layer; the reinforcing layer and the modified sulfonated composite resin layer are tightly combined by hot pressing, which significantly improves the overall mechanical strength of the membrane.

[0015] 2, The proton exchange membrane for PEM water electrolysis and the preparation method thereof described in the application, the reasonable ratio of perfluorosulfonic acid resin and sulfonated lignin in the modified sulfonated composite resin layer of the proton exchange membrane provides sufficient active sites for proton conduction; the water retention layer is prepared by spinning the sulfonated polyaryletherketone solution on the surface of the reinforcing layer using the electrospinning technology, has good water retention performance, can maintain the continuity of the proton conduction channel, and ensures efficient electrolysis.

[0016] 3, The proton exchange membrane for PEM water electrolysis and the preparation method thereof described in the application, the core-shell structure design is adopted in the catalyst layer of the proton exchange membrane, the transition metal oxide shell layer and the noble metal core layer synergistically act, and the catalytic activity is improved.

[0017] 4, The proton exchange membrane for PEM water electrolysis and the preparation method thereof described in the application, the micron-level pyramid array is constructed in the anti-permeation layer of the proton exchange membrane through the photolithography-etching method, and is modified through fluorosilane vapor deposition, so that the structure with the super-hydrophobic surface layer and the hydrophilic bottom layer is formed; the structure reduces the water transmission resistance, effectively blocks the cross penetration of hydrogen and oxygen, and improves the gas production purity and operation safety.

[0018] 5, The proton exchange membrane for PEM water electrolysis and the preparation method thereof described in the application, the layers of the proton exchange membrane are closely combined through reasonable process parameter control, such as the hot pressing of the reinforcing layer and the modified sulfonated composite resin layer, the interface treatment of the water retention layer and the reinforcing layer, the interlayer peeling phenomenon is reduced, the overall stability of the membrane is improved, and the performance stability of the membrane in the long-term operation process is ensured. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be clearly and completely described below, obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0020] In the following specific embodiments: The "parts" described below are all mass parts, except for special instructions.

[0021] Perfluorosulfonic acid resin: the molecular formula is C9HF 17 O5S, the hydrogen ion capacity is 0.86mmol / g, and the particle size is 2μm, the particle size is 2μm; Sulfonated lignin: the sulfonation rate is 1.0mmol / g, and the particle size is 1μm; Release film: PET release film, thickness is 50μm; Carbon nanotube: 2 nm in diameter, 15 μm in length; Perfluorosulfonic acid resin solution: 20 wt% perfluorosulfonic acid resin, 80 wt% solvent, the solvent is a mixed solvent of water and n-propanol, the volume ratio of water to n-propanol is 4:6.

[0022] Example 1: A preparation method of a proton exchange membrane for PEM water electrolysis, comprising the following steps: (1) Preparation of a modified sulfonated composite resin layer: disperse perfluorosulfonic acid resin and sulfonated lignin in N,N-dimethylformamide, under an ultrasonic power of 300 W, disperse for 60 min, then coat on the surface of a release film, dry at 50°C for 20 min, to obtain a modified sulfonated composite resin layer; the mass ratio of perfluorosulfonic acid resin, sulfonated lignin and N,N-dimethylformamide is 7:2:40; (2) Preparation of a reinforcing layer: blend PTFE emulsion, carbon nanotubes and tetrafluoroethylene-hexafluoropropylene copolymer according to a mass ratio of 75:2:8, sinter at a casting speed of 0.5 m / min, a scraper gap of 50 μm and a sintering temperature of 350°C for 40 min; then treat under Ar / O2 mixed gas (volume ratio 4:1, flow rate 20 sccm) at a power of 120 W for 8 min to obtain a reinforcing layer; the reinforcing layer is hot-pressed with the modified sulfonated composite resin layer at 80°C and a pressure of 0.2 MPa for 12 min; the solid content of the PTFE emulsion is 50%; (3) Preparation of a water retention layer: use electrospinning technology to spin a sulfonated polyaryletherketone solution with a solid content of 15% on the surface of the reinforcing layer at a spinning voltage of 12 kV, a receiving distance of 15 cm and a pushing rate of 0.5 mL / h, and dry at 70°C for 25 min to form a water retention layer; the solvent of the sulfonated polyaryletherketone solution is N,N-dimethylformamide; (4) Preparation of a catalyst layer: spray a transition metal oxide precursor solution on the surface of the water retention layer, dry, then spray a noble metal precursor solution, dry at 65°C for 20 min to form a catalyst layer; the transition metal oxide precursor solution comprises the following mass components: 0.5 parts of chloroiridic acid solution, 2 parts of citric acid, 15 parts of perfluorosulfonic acid resin solution, 30 parts of anhydrous ethanol and 52.5 parts of deionized water; the noble metal precursor solution comprises the following mass components: 0.3 parts of chloroplatinic acid solution, 15 parts of perfluorosulfonic acid resin solution, 0.1 parts of sodium dodecyl sulfate, 30 parts of ethylene glycol and 54.6 parts of deionized water; the concentration of the chloroiridic acid solution is 0.1%, and the concentration of the chloroplatinic acid solution is 1%; (5) Preparation of the impermeable layer: Construct a pyramid array with a height of 4 μm and a pitch of 8 μm on the surface of the catalyst layer by photolithography-etching method; coat perfluorosulfonic acid resin and then modify by fluorosilane vapor deposition, dry at 110°C in a nitrogen atmosphere for 90 min, and peel off the release film to obtain the proton exchange membrane; the process conditions of the photolithography-etching method are: photolithography exposure wavelength 365 nm, photolithography energy 100 mJ / cm 2 , photolithography time 20 s, etching gas CF4 gas, etching power 180 W, and etching time 8 min; the process conditions of the fluorosilane vapor deposition are: temperature 80°C, and time 40 min; The prepared proton exchange membrane has the following thicknesses: the modified sulfonated composite resin layer has a thickness of 20 μm; the reinforcing layer has a thickness of 3 μm; the water retention layer has a thickness of 20 μm; the catalyst layer has a thickness of 0.4 μm; and the impermeable layer has a thickness of 0.8 μm.

[0023] Example 2: A method for preparing a proton exchange membrane for PEM water electrolysis, comprising the following steps: (1) Preparation of the modified sulfonated composite resin layer: disperse perfluorosulfonic acid resin and sulfonated lignin in N-methylpyrrolidone under an ultrasonic power of 350 W, disperse for 45 min, coat on the surface of a release film, and dry at 55°C for 18 min to obtain the modified sulfonated composite resin layer; the mass ratio of perfluorosulfonic acid resin, sulfonated lignin, and N-methylpyrrolidone is 7.5:3:50; (2) Preparation of the reinforcing layer: blend PTFE emulsion, carbon nanotubes, and tetrafluoroethylene-hexafluoropropylene copolymer according to a mass ratio of 78:4:15, sinter at a casting speed of 1.0 m / min, a doctor blade gap of 60 μm, and a sintering temperature of 360°C for 35 min, then treat under Ar / O2 mixed gas (volume ratio 4.2:1, flow rate 30 sccm) at a power of 130 W for 6 min to obtain the reinforcing layer; hot-press the reinforcing layer with the modified sulfonated composite resin layer at 100°C and a pressure of 0.25 MPa for 10 min; the solid content of the PTFE emulsion is 55%; (3) Preparation of the water retention layer: use electrospinning technology to spin a sulfonated polyaryletherketone solution with a solid content of 18% on the surface of the reinforcing layer at a spinning voltage of 14 kV, a receiving distance of 18 cm, and a pushing rate of 0.8 mL / h, and dry at 75°C for 22 min to form the water retention layer; the solvent of the sulfonated polyaryletherketone solution is N-methylpyrrolidone; (4) Preparing the catalyst layer: spraying the transition metal oxide precursor solution on the surface of the water-retention layer, drying, then spraying the noble metal precursor solution, drying at 70℃ for 18 min, forming the catalyst layer; the transition metal oxide precursor solution includes the following mass components: 0.6 parts of chloroiridic acid solution, 3 parts of citric acid, 11 parts of perfluorosulfonic acid resin solution, 33 parts of anhydrous ethanol, 52.4 parts of deionized water; the noble metal precursor solution includes the following mass components: 0.4 parts of chloroplatinic acid solution, 18 parts of perfluorosulfonic acid resin solution, 0.2 parts of sodium dodecyl sulfate, 32 parts of ethylene glycol, 49.4 parts of deionized water; the concentration of the chloroiridic acid solution is 0.5%, and the concentration of the chloroplatinic acid solution is 0.5%; (5) Preparing the impermeable layer: constructing a pyramid array with a height of 5 μm and a pitch of 10 μm on the surface of the catalyst layer by the photolithography-etching method; after coating the perfluorosulfonic acid resin and modifying by fluorosilane vapor deposition, drying at 115℃ in a nitrogen atmosphere for 75 min, and peeling off the release film, a proton exchange membrane is obtained; the process conditions of the photolithography-etching method are as follows: photolithography exposure wavelength 365 nm, photolithography energy 150 mJ / cm 2 , photolithography time 15 s, etching gas CF4 gas, etching power 190 W, etching time 6 min; the fluorosilane vapor deposition process conditions are as follows: temperature 90℃, time 35 min; The prepared proton exchange membrane has the following thicknesses: the modified sulfonated composite resin layer has a thickness of 22 μm; the reinforcing layer has a thickness of 4 μm; the water-retention layer has a thickness of 19 μm; the catalyst layer has a thickness of 0.6 μm; and the impermeable layer has a thickness of 0.9 μm.

[0024] Example 3: A method for preparing a proton exchange membrane for PEM water electrolysis, including the following steps: (1) Preparing the modified sulfonated composite resin layer: dispersing perfluorosulfonic acid resin and sulfonated lignin in dimethyl sulfoxide under an ultrasonic power of 400 W for 30 min, then coating on the surface of a release film, and drying at 60℃ for 15 min to obtain the modified sulfonated composite resin layer; the mass ratio of the perfluorosulfonic acid resin, the sulfonated lignin, and the dimethyl sulfoxide is 8:2.5:60; (2) Preparing the reinforcing layer: blending PTFE emulsion, carbon nanotubes, and tetrafluoroethylene-hexafluoropropylene copolymer according to a mass ratio of 80:3:10, sintering at a casting speed of 1.5 m / min, a doctor blade gap of 80 μm, and a sintering temperature of 380℃ for 30 min, then treating under Ar / O2 mixed gas (volume ratio 4.5:1, flow rate 50 sccm) at a power of 150 W for 5 min to obtain the reinforcing layer; the reinforcing layer is hot-pressed with the modified sulfonated composite resin layer at 120℃ and a pressure of 0.3 MPa for 8 min; the solid content of the PTFE emulsion is 60%; (3) Preparation of water retention layer: using electrospinning technology, under the conditions of spinning voltage 18 kV, receiving distance 20 cm, and pushing rate 1.0 mL / h, a sulfonated polyaryletherketone solution with solid content of 20% is spun on the surface of the reinforcing layer, and is dried at 80°C for 20 min to form a water retention layer; the solvent of the sulfonated polyaryletherketone solution is dimethyl sulfoxide; (4) Preparation of catalyst layer: a transition metal oxide precursor solution is sprayed on the surface of the water retention layer, after drying, a noble metal precursor solution is sprayed, and after drying at 75°C for 15 min, a catalyst layer is formed; the transition metal oxide precursor solution comprises the following mass components: 0.8 parts of chloroiridic acid solution, 3 parts of citric acid, 15 parts of perfluorosulfonic acid resin solution, 35 parts of anhydrous ethanol, and 46.2 parts of deionized water; the noble metal precursor solution comprises the following mass components: 0.5 parts of chloroplatinic acid solution, 20 parts of perfluorosulfonic acid resin solution, 0.3 parts of sodium dodecyl sulfate, 35 parts of ethylene glycol, and 44.2 parts of deionized water; the concentration of the chloroiridic acid solution is 1%, and the concentration of the chloroplatinic acid solution is 0.1%; (5) Preparation of impermeable layer: a pyramid array with a height of 6 μm and a pitch of 12 μm is constructed on the surface of the catalyst layer by photolithography-etching method; after being coated with perfluorosulfonic acid resin and modified by fluorosilane vapor deposition, the sample is dried at 120°C in a nitrogen atmosphere for 60 min, and the release film is peeled off, thereby obtaining a proton exchange membrane; the process conditions of the photolithography-etching method are as follows: photolithography exposure wavelength 365 nm, photolithography energy 200 mJ / cm 2 , photolithography time 10 s, etching gas CF4, etching power 200 W, and etching time 5 min; the process conditions of the fluorosilane vapor deposition are as follows: temperature 100°C, and time 30 min.

[0025] The prepared proton exchange membrane has the following thicknesses: the modified sulfonated composite resin layer has a thickness of 25 μm; the reinforcing layer has a thickness of 5 μm; the water retention layer has a thickness of 22 μm; the catalyst layer has a thickness of 0.7 μm; and the impermeable layer has a thickness of 1.2 μm.

[0026] Comparative Example 1: based on Example 1, step (1) is adjusted, and no sulfonated lignin is added, and the only difference from Example 1 is that: (1) preparation of modified sulfonated composite resin layer: perfluorosulfonic acid resin is dispersed in N,N-dimethylformamide under ultrasonic power of 300 W for 60 min, and then is coated on the surface of a release film, and is dried at 50°C for 20 min to obtain a modified sulfonated composite resin layer; the mass ratio of perfluorosulfonic acid resin to N,N-dimethylformamide is 7:40.

[0027] Comparative Example 2: Based on Example 1, adjusting step (4), not spraying noble metal precursor solution, the difference from Example 1 is only in that: (4) Preparation of catalyst layer: spray transition metal oxide precursor solution on the surface of water retention layer, after drying, the catalyst layer is obtained; the transition metal oxide precursor solution comprises the following mass components: 0.5 parts of chloro iridic acid solution, 2 parts of citric acid, 15 parts of perfluorosulfonic acid resin solution, 30 parts of anhydrous ethanol, 52.5 parts of deionized water; the concentration of chloro iridic acid solution is 0.1%.

[0028] Comparative Example 3: Based on Example 1, adjusting step (5), not using photolithography-etching method to construct pyramid array, the difference from Example 1 is only in that: (5) Preparation of impermeable layer: after coating perfluorosulfonic acid resin on the surface of catalyst layer, fluorosilane vapor deposition modification is carried out, 110℃ nitrogen atmosphere drying for 90min, peeling off the release film, the proton exchange membrane is obtained; the fluorosilane vapor deposition process conditions are: temperature 80℃, time 40min.

[0029] Experiment: Take the proton exchange membranes obtained in Examples 1-3 and Comparative Examples 1-3 to prepare samples, and detect the performance of the samples respectively and record the detection results: Mechanical property test: the tensile strength of the sample is tested according to GB / T20042.3-2022, the testing instrument is a universal material testing machine, and the tensile rate is 50mm / min; Proton conductivity test: the sample is tested according to GB / T20042.3-2022, and an electrochemical impedance tester is used to test under the condition of a test temperature of 80℃ and a relative humidity of 50%; Hydrogen permeability test: a gas permeation instrument is used to measure the hydrogen permeation rate through the membrane at room temperature, and the hydrogen permeability is calculated; Catalytic activity stability test: the membrane is assembled into an electrolytic cell, which is continuously operated for 500h under certain electrolysis conditions (voltage 1.8V, temperature 80℃), the current density of the electrolytic cell is tested regularly, and the catalytic activity decay is evaluated; Water absorption test: the sample is tested according to GB / T20042.3-2022, the sample is immersed in boiling distilled water at 100℃, after immersion for 1h, the sample is quickly transferred to room temperature distilled water for cooling for 15min, the sample is taken out from the water, the surface of the sample is absorbed with filter paper, weighed within 30s, and the water absorption is calculated.

[0030] Table 1 Test results of examples and comparative examples

[0031] Conclusion: From the data comparison, the proton exchange membrane prepared by example 1-3 is excellent in mechanical strength, proton conductivity, catalytic stability and water absorption rate, forms a functional membrane system with complete structure and balanced performance, and verifies the rationality of the overall technical scheme of the application. Comparative example 1, on the basis of example 1, when preparing the modified sulfonated composite resin layer, no sulfonated lignin is added, only perfluorosulfonic acid resin and solvent are mixed to prepare, which leads to a significant decrease in performance: this shows that the introduction of sulfonated lignin can form a synergistic effect with perfluorosulfonic acid resin, which can not only enhance the mechanical support of the membrane, but also optimize the proton conduction channel, and is a key component to ensure the basic performance of the membrane; Comparative example 2, on the basis of example 1, when preparing the catalyst layer, no noble metal precursor solution is sprayed, which leads to a significant decrease in catalytic stability, which shows that the synergistic effect of the transition metal oxide shell layer and the noble metal core layer is the core design to improve the activity of the catalytic layer; Comparative example 3, on the basis of example 1, when preparing the impermeable layer, the step of constructing a pyramid array by photolithography-etching is not used, and the resin is directly coated and modified, which leads to a significant increase in water absorption rate, which shows that the micron-level pyramid array can significantly improve the barrier ability of the impermeable layer by increasing the gas diffusion path and optimizing the surface hydrophobicity; In summary, the proton exchange membrane for PEM water electrolysis prepared by the five-layer structure design and optimized process of the application is excellent in mechanical properties, proton conductivity, catalytic stability and water absorption rate, can meet the practical application requirements of PEM water electrolysis hydrogen production technology, and has good popularization prospect.

[0032] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered as exemplary and non-limiting, and the scope of the application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the application.

Claims

1. A method for preparing a proton exchange membrane for PEM water electrolysis, characterized in that: Includes the following steps: (1) Preparation of modified sulfonated composite resin layer: Perfluorosulfonic acid resin and sulfonated lignin are dispersed in solvent, ultrasonically dispersed, coated on the surface of release film, and dried to obtain modified sulfonated composite resin layer. (2) Preparation of reinforcing layer: PTFE emulsion, carbon nanotubes and tetrafluoroethylene-hexafluoropropylene copolymer are blended, cast and sintered, and then plasma treated to obtain reinforcing layer, which is then hot-pressed and bonded to modified sulfonated composite resin layer. (3) Preparation of water-retaining layer: Using electrospinning technology, sulfonated polyaryletherketone solution is spun onto the surface of the reinforcing layer and dried at 70-80℃ for 20-25 min to form a water-retaining layer; (4) Preparation of catalyst layer: Spray transition metal oxide precursor solution onto the surface of water-retaining layer, dry it, spray noble metal precursor solution, dry at 65-75℃ for 15-20 min to form catalyst layer. (5) Preparation of the impermeable layer: A pyramid array is constructed on the surface of the catalyst layer by photolithography-etching method; After coating with perfluorosulfonic acid resin, the membrane is modified by fluorosilane vapor deposition, dried at 110-120℃ in a nitrogen atmosphere for 60-90 minutes, and the release membrane is peeled off to obtain the proton exchange membrane.

2. The method for preparing a proton exchange membrane for PEM water electrolysis according to claim 1, characterized in that: In step (1), the solvent is one of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; The mass ratio of the perfluorosulfonic acid resin, sulfonated lignin, and solvent is (7-8):(2-3):(40-60).

3. The method for preparing a proton exchange membrane for PEM water electrolysis according to claim 2, characterized in that: In step (1), the ultrasonic dispersion process conditions are: ultrasonic power 300-400W, time 30-60min; The drying process conditions are: temperature 50-60℃, time 15-20min.

4. The method for preparing a proton exchange membrane for PEM water electrolysis according to claim 1, characterized in that: In step (2), the mass ratio of the PTFE emulsion, carbon nanotubes, and tetrafluoroethylene-hexafluoropropylene copolymer is (75-80):(2-4):(8-15); the solid content of the PTFE emulsion is 50-60%.

5. The method for preparing a proton exchange membrane for PEM water electrolysis according to claim 4, characterized in that: In step (2), the process conditions for tape casting and sintering are: tape casting speed 0.5-1.5m / min, scraper gap 50-80μm, sintering temperature 350-380℃, and sintering time 30-40min; The plasma treatment process conditions are: Ar / O2 mixed gas, power 120-150W, time 5-8min; The hot-press bonding process conditions are: temperature 80-120℃, pressure 0.2-0.3MPa, and time 8-12min.

6. The method for preparing a proton exchange membrane for PEM water electrolysis according to claim 1, characterized in that: In step (3), the solid content of the sulfonated polyaryletherketone solution is 15-20%, and the solvent is one of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide. The process conditions for the electrospinning technology are: spinning voltage 12-18kV, receiving distance 15-20cm, and feed rate 0.5-1.0mL / h.

7. The method for preparing a proton exchange membrane for PEM water electrolysis according to claim 1, characterized in that: In step (4), the transition metal oxide precursor solution comprises the following components by mass: 0.5-0.8 parts chloroiridium acid solution, 2-3 parts citric acid, 10-15 parts perfluorosulfonic acid resin solution, 30-35 parts anhydrous ethanol, and 46.2-57.5 parts deionized water; The noble metal precursor solution comprises the following components by mass: 0.3-0.5 parts chloroplatinic acid solution, 15-20 parts perfluorosulfonic acid resin solution, 0.1-0.3 parts sodium dodecyl sulfate, 30-35 parts ethylene glycol, and 44.2-54.6 parts deionized water.

8. The method for preparing a proton exchange membrane for PEM water electrolysis according to claim 1, characterized in that: In step (5), the height of the pyramid array is 4-6 μm and the spacing is 8-12 μm; The process conditions for the photolithography-etching method are: photolithography exposure wavelength 365nm, photolithography energy 100-200mJ / cm². 2 Photolithography time 10-20s, etching gas CF4 gas, etching power 180-200W, etching time 5-8min; The fluorosilane vapor deposition process conditions are: temperature 80-100℃, time 30-40min.

9. The method for preparing a proton exchange membrane for PEM water electrolysis according to claim 1, characterized in that: The modified sulfonated composite resin layer has a thickness of 20-25 μm; the reinforcing layer has a thickness of 3-5 μm; the water-retaining layer has a thickness of 18-22 μm; the catalyst layer has a thickness of 0.4-0.7 μm; and the anti-permeability layer has a thickness of 0.8-1.2 μm.

10. A proton exchange membrane for PEM water electrolysis, characterized in that: It is prepared by the preparation method according to any one of claims 1-9.

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