An integrated enhanced membrane for water electrolysis and a preparation method and application thereof

Abstract

The present application relates to a kind of integrated reinforcing membrane for water electrolysis and its preparation method and application, the integrated reinforcing membrane for water electrolysis includes reinforcing fabric and short side chain perfluorosulfonic acid resin covering the reinforcing fabric;The reinforcing fabric includes aromatic polymer mesh cloth.The integrated reinforcing membrane for water electrolysis provided by the present application is made into the proton exchange membrane for water electrolysis by protonation treatment, with the characteristics of low surface resistance, high wet tensile property, good dimensional stability under high temperature and high pressure water electrolysis working condition, and with gas barrier ability can reduce the risk of mixed gas.

Description

Technical Field

[0001] This invention relates to the field of ion exchange membrane technology, and in particular to an integrated reinforced membrane for water electrolysis, its preparation method, and its application. Background Technology

[0002] Proton exchange membrane electrolysis (PEMWE) has become an important development direction for high-end hydrogen production equipment due to its advantages such as high current density, high hydrogen purity, and compact system. In existing PEMWE systems, the commonly used proton exchange membranes are mainly perfluorosulfonic acid resin-based membrane materials, such as long-side-chain Nafion membranes and short-side-chain perfluorosulfonic acid resin membranes (e.g., products from Synesqo, 3M, etc.). Comparatively, short-side-chain perfluorosulfonic acid resin membranes typically have higher exchange capacity and glass transition temperature, and their proton conductivity and thermal stability are significantly better than those of long-side-chain perfluorosulfonic acid resin membranes.

[0003] However, existing proton exchange membranes still have the following problems: (1) Insufficient mechanical strength and dimensional stability: Under high temperature (e.g., 80~120℃) and high pressure (e.g., 0.5~10.0 MPa) water electrolysis conditions, swelling, creep and thickness direction compression deformation are prone to occur, resulting in a decrease in the fastening force of the membrane electrode assembly (MEA), sealing failure and local short circuit risk, which seriously affects the life and safety. (2) The contradiction between resistance and strength: In order to improve mechanical strength, existing technologies often improve dimensional stability and pressure resistance by increasing the thickness of the proton exchange membrane or adding high content of filler, but this will significantly increase the surface resistivity (ASR), reduce energy efficiency and increase hydrogen production energy consumption.

[0004] Under the high temperature and high hydration conditions of proton exchange membrane (PEM) water electrolysis devices, the wet modulus of PEMs decreases significantly, making them prone to creep and dimensional instability under long-term compression and pressure differential. This type of mechanical failure often precedes chemical aging, becoming one of the key engineering bottlenecks restricting system lifespan. Existing reinforced PEMs mostly use PTFE or glass fiber mesh as the reinforcing framework and are primarily designed for fuel cell operating conditions (lower temperatures and pressures). They lack sufficient consideration for the high-temperature and high-pressure conditions of PEM water electrolysis, exhibiting limitations in pressure resistance, long-term hydration stability, and processing technology. Furthermore, their compatibility with short-chain perfluorosulfonic acid (PFSA) resins is not ideal, thus limiting the advantages of short-chain PFSA PEMs in hydrogen production through water electrolysis.

[0005] Therefore, there is an urgent need to develop a short-side-chain perfluorosulfonic acid resin matrix exchange membrane that can balance low surface resistivity, high mechanical strength and dimensional stability, reduce the risk of gas mixing, and is suitable for high-temperature and high-pressure water electrolysis. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an integrated reinforced membrane for water electrolysis, its preparation method, and its application. The integrated reinforced membrane for water electrolysis, based on a short-side-chain perfluorosulfonic acid resin and reinforcing fabric, is a proton exchange membrane for water electrolysis prepared through protonation treatment. It features low sheet resistance, high wet tensile strength, good dimensional stability under high-temperature and high-pressure water electrolysis conditions, and gas barrier capabilities, reducing the risk of gas mixing.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides an integrated reinforced membrane for water electrolysis, the integrated reinforced membrane for water electrolysis comprising a reinforcing fabric and a short-side-chain perfluorosulfonic acid resin covering the reinforcing fabric; the reinforcing fabric comprising an aromatic polymer mesh.

[0008] This invention addresses the engineering challenges of proton exchange membrane (PEM) water electrolysis under conditions of high temperature, high hydration, and high pressure, where the wet modulus of short-chain perfluorosulfonic acid resin is significantly reduced and prone to creep instability. By coating short-chain perfluorosulfonic acid resin with an aromatic polymer mesh to form an integrated reinforced membrane for water electrolysis, and then protonating it, the resulting PEM for water electrolysis forms a thermally, hydrolyzed, and mechanically synergistically matched system. It retains the high proton conductivity and low sheet resistivity of short-chain perfluorosulfonic acid resin while significantly improving wet tensile properties and dimensional stability. It exhibits excellent heat resistance, chemical corrosion resistance, and hydrolysis resistance, enabling it to withstand long-term cyclic operation under high temperature and high pressure conditions, reducing creep and failure. It is suitable for high-temperature and high-pressure water electrolysis hydrogen production, and helps improve the safety and service life of the electrolyzer without significantly increasing energy consumption.

[0009] In this invention, the high temperature refers to 80~120℃, the high pressure refers to a cathode pressure of 0.5~10.0 MPa(G) and an anode pressure of 0.1~0.5 MPa(G).

[0010] In this invention, MPa(G) refers to the unit of gauge pressure.

[0011] In this invention, the wet tensile properties refer to the tensile properties obtained by tensile testing under conditions of 25°C and 100% relative humidity.

[0012] Preferably, the thickness of the aromatic polymer mesh is 10~100 μm (e.g., 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm or 90 μm, etc.), more preferably 30~90 μm, and even more preferably 40~70 μm.

[0013] Preferably, the aromatic polymer mesh has a unit area mass of 5~40 g / m².2 (e.g., 10 g / m 2 15 g / m 2 20 g / m 2 25 g / m 2 30 g / m 2 Or 35 g / m 2 (etc.), and more preferably 10~20 g / m 2 .

[0014] Preferably, the porosity of the aromatic polymer mesh is 20% to 90% (e.g., 30%, 40%, 50%, 60%, 70% or 80%), and more preferably 50% to 70%.

[0015] Preferably, the aromatic polymer mesh is made of an aromatic polymer.

[0016] Preferably, the aromatic polymer comprises polyetheretherketone (PEEK) and / or polyphenylene sulfide (PPS).

[0017] In this invention, the aromatic high-performance polymers such as polyether ether ketone (PEEK) and polyphenylene sulfide (PPS) can maintain structural stability under conditions of high temperature (80~120℃), high pressure (0.1~10.0 MPa(G)), and full hydration (saturated with deionized water), maintaining high modulus and low creep rate. They can provide effective skeletal support when short-side chain perfluorosulfonic acid resin swells and softens, thus enabling the proton exchange membrane for water electrolysis, made from an integrated reinforced membrane, to simultaneously achieve low ohmic impedance, high wet mechanical properties, and dimensional stability under relatively thin conditions.

[0018] Preferably, the aromatic polymer mesh is a treated aromatic polymer mesh.

[0019] Preferably, the process includes cleaning and surface activation treatment.

[0020] In this invention, cleaning and surface activation treatment of the aromatic polymer mesh helps to improve its interfacial bonding strength with short-side-chain perfluorosulfonic acid resin.

[0021] For example, the surface activation treatment includes any one or a combination of at least two of plasma treatment, chemical oxidation treatment, or surface-initiated grafting treatment.

[0022] Preferably, the ion exchange capacity (IEC) of the short-side-chain perfluorosulfonic acid resin is 0.8~1.5 meq / g (e.g., 0.9 meq / g, 1.0 meq / g, 1.1 meq / g, 1.2 meq / g, 1.3 meq / g or 1.4 meq / g, etc.), and more preferably 1.2~1.4 meq / g.

[0023] In this invention, the short-side-chain perfluorosulfonic acid resin refers to a perfluorosulfonic acid resin with 2 to 5 carbon atoms in its side chain (e.g., 3 or 4). Exemplarily, the short-side-chain perfluorosulfonic acid resin can be a commercially available short-side-chain PFSA resin, such as Aquivion resins, 3M resins, etc., whose side chain structure includes -CF2-CF2-SO2F and / or -CF2-CF2-SO3H.

[0024] Preferably, the thickness of the integrated reinforced membrane for water electrolysis is 20~500 μm (e.g., 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm or 450 μm, etc.), more preferably 50~150 μm, and even more preferably 70~100 μm.

[0025] In this invention, the thickness of the integrated reinforced membrane used for water electrolysis is preferably controlled within the range of 50 to 150 μm. This allows the integrated reinforced membrane used for water electrolysis to maintain low resistance while still possessing sufficient hydrogen barrier capacity, thus effectively reducing the risk of hydrogen cross-permeation and gas mixing. A thickness of 70 to 100 μm for the integrated reinforced membrane used for water electrolysis is also preferred, as it results in better mechanical properties, lower sheet resistance, and superior overall performance.

[0026] In a second aspect, the present invention provides a method for preparing an integrated reinforcing membrane for water electrolysis as described in the first aspect, the method comprising the following steps: impregnating a reinforcing fabric with a short-side-chain perfluorosulfonic acid resin solution, pre-drying, forming a coating film on the reinforcing fabric, optionally repeating the above steps to form at least two coating films on the reinforcing fabric, drying, and heat treatment to obtain the integrated reinforcing membrane for water electrolysis.

[0027] In this invention, the preparation method involves completely impregnating and coating the reinforcing fabric with a short-side-chain perfluorosulfonic acid resin solution, forming a continuous phase coating structure inside the pores of the reinforcing fabric, thus constituting an integrated reinforcing structure. This results in an integrated reinforcing membrane for water electrolysis that possesses both high mechanical strength and low electrical resistance, making it suitable for high-temperature and high-pressure water electrolysis conditions.

[0028] Preferably, the impregnation of the reinforcing fabric with a short-side-chain perfluorosulfonic acid resin solution includes using a solution casting method to allow the short-side-chain perfluorosulfonic acid resin solution to enter the interior of the reinforcing fabric and form a continuous phase coating on the reinforcing fabric.

[0029] For example, the impregnation by casting includes spreading the reinforcing fabric flat on a flat substrate, casting a short-side-chain perfluorosulfonic acid resin solution onto the reinforcing fabric with a certain wet film thickness (e.g., 100~600 μm), allowing the short-side-chain perfluorosulfonic acid resin solution to penetrate into the pores of the reinforcing fabric under the action of gravity and / or a scraper, achieving complete impregnation, and coating the skeleton of the reinforcing fabric with the short-side-chain perfluorosulfonic acid resin.

[0030] Preferably, the short-side-chain perfluorosulfonic acid resin solution comprises a short-side-chain perfluorosulfonic acid resin and a polar solvent.

[0031] Preferably, the polar solvent includes any one or a combination of at least two of N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), alcohol solvents, or water.

[0032] Preferably, the solid content of the short-side-chain perfluorosulfonic acid resin solution is 5wt%~30wt% (e.g., 8wt%, 11wt%, 14wt%, 17wt%, 20wt%, 23wt%, 26wt% or 29wt%, etc.).

[0033] Preferably, the pre-drying temperature is 40~80℃ (e.g., 45℃, 50℃, 55℃, 60℃, 65℃, 70℃ or 75℃, etc.), and the pre-drying time is 0.5~5 h (e.g., 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h or 4.5 h, etc.).

[0034] Preferably, the drying temperature is 80℃~120℃ (e.g., 85℃, 90℃, 95℃, 100℃, 105℃, 110℃ or 115℃, etc.), and the drying time is 0.5~5 h (e.g., 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h or 4.5 h, etc.).

[0035] Preferably, the heat treatment temperature is 50~220℃ (e.g., 70℃, 90℃, 110℃, 130℃, 150℃, 170℃, 190℃ or 210℃, etc.), and more preferably 120~200℃ (e.g., 130℃, 140℃, 150℃, 160℃, 170℃, 180℃ or 190℃, etc.).

[0036] Preferably, the heat treatment time is 0.5 to 10 h (e.g., 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h or 9 h, etc.), and more preferably 0.5 to 1.0 h.

[0037] In this invention, the pre-drying and drying steps are for removing polar solvents, and the subsequent heat treatment can further form a dense, integrated, integrated reinforced membrane for water electrolysis.

[0038] In this invention, by controlling the casting amount, the thickness can be controlled, and the film thickness can be precisely controlled.

[0039] Thirdly, the present invention provides a proton exchange membrane for water electrolysis, wherein the proton exchange membrane for water electrolysis is prepared by protonation treatment of the integrated reinforced membrane for water electrolysis as described in the first aspect.

[0040] Preferably, the protonation treatment includes protonation using an acid solution.

[0041] Preferably, the acid solution includes a sulfuric acid solution.

[0042] Preferably, the concentration of the sulfuric acid solution is 0.1~1.0 mol / L (e.g. 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L or 0.9 mol / L, etc.).

[0043] Preferably, the protonation treatment further includes washing to a pH of 6-7 (e.g., 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, or 6.9).

[0044] Preferably, the proton exchange membrane used for water electrolysis has a sheet resistivity of ≤80 mΩ·cm under conditions of 80°C and full hydration of deionized water. 2 (e.g., 10 mΩ·cm) 2 20 mΩ·cm 2 30 mΩ·cm 2 40 mΩ·cm 2 50 mΩ·cm 2 60 mΩ·cm 2 or 70 mΩ·cm 2 (etc.), and more preferably ≤50 mΩ·cm 2 .

[0045] Preferably, the proton exchange membrane used for water electrolysis has a tensile strength ≥25 MPa (e.g., 26 MPa, 27 MPa, 28 MPa, 29 MPa, 30 MPa, 31 MPa, 32 MPa, 33 MPa, 34 MPa or 35 MPa, etc.) at 25°C and 100% relative humidity, and more preferably ≥30 MPa.

[0046] Preferably, the size change rate of the proton exchange membrane used for water electrolysis after soaking in deionized water at 80°C for 24 h is ≤20% (e.g., 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, or 18%), and more preferably ≤15%.

[0047] In this invention, the dimensional change rate of the proton exchange membrane used for water electrolysis after soaking in deionized water at 80°C for 24 h refers to the initial dry membrane sample of 30 mm × 30 mm after being placed in a test environment (25°C, 65%RH) for 24 h, and then soaked in deionized water at 80°C for 24 h. The expansion rate in the length and width directions of the soaked membrane sample is measured respectively, and the average value is taken.

[0048] Fourthly, the present invention provides a water electrolysis apparatus, the water electrolysis apparatus comprising an anode chamber, a cathode chamber, and a proton exchange membrane for water electrolysis as described in the third aspect, disposed between the anode chamber and the cathode chamber.

[0049] Fifthly, the present invention provides the application of any one of the integrated reinforced membrane for water electrolysis as described in the first aspect, the proton exchange membrane for water electrolysis as described in the third aspect, or the water electrolysis device as described in the fourth aspect in water electrolysis hydrogen production.

[0050] Preferably, the temperature for hydrogen production by water electrolysis is 80~120℃ (e.g., 85℃, 90℃, 95℃, 100℃, 105℃, 110℃ or 115℃, etc.).

[0051] Preferably, the cathode pressure for hydrogen production by water electrolysis is 0.5~10.0 MPa(G), such as 1.0 MPa(G), 2.0 MPa(G), 3.0 MPa(G), 4.0 MPa(G), 5.0 MPa(G), 6.0 MPa(G), 7.0 MPa(G), 8.0 MPa(G), or 9.0 MPa(G), and the anode pressure is 0.1~0.5 MPa(G), such as 0.15 MPa(G), 0.20 MPa(G), 0.25 MPa(G), 0.30 MPa(G), 0.35 MPa(G), 0.40 MPa(G), or 0.45 MPa(G).

[0052] Preferably, the cathode pressure for hydrogen production by water electrolysis is 1.0~5.0 MPa(G), such as 1.5 MPa(G), 2.0 MPa(G), 2.5 MPa(G), 3.0 MPa(G), 3.5 MPa(G), 4.0 MPa(G), or 4.5 MPa(G), and the anode pressure is 0.1~0.3 MPa(G), such as 0.12 MPa(G), 0.14 MPa(G), 0.16 MPa(G), 0.18 MPa(G), 0.20 MPa(G), 0.22 MPa(G), 0.24 MPa(G), 0.26 MPa(G), or 0.28 MPa(G).

[0053] In this invention, the preparation method adopts conventional solution casting and heat treatment processes, which do not require complex equipment, can be scaled up, are suitable for large-scale production, and are conducive to industrialization and promotion.

[0054] Compared with the prior art, the present invention has at least the following beneficial effects: The integrated reinforced membrane for water electrolysis described in this invention, manufactured through protonation treatment, exhibits low sheet resistivity, high mechanical strength, and good dimensional stability under high-temperature and high-pressure water electrolysis conditions. It also possesses gas barrier capabilities and reduces the risk of gas mixing. The sheet resistivity of the proton exchange membrane for water electrolysis is ≤80 mΩ·cm under conditions of 80°C and full hydration of deionized water. 2 The proton exchange membrane used for water electrolysis has a tensile strength ≥25 MPa at 25°C and 100% relative humidity, and a dimensional change rate ≤20% after immersion in deionized water at 80°C for 24 h. Preferably, the sheet resistivity of the proton exchange membrane used for water electrolysis is ≤50 mΩ·cm under conditions of 80°C and full hydration in deionized water. 2 The proton exchange membrane used for water electrolysis has a tensile strength ≥30 MPa at 25°C and 100% relative humidity, and the dimensional change rate of the proton exchange membrane used for water electrolysis is ≤15% after immersion in deionized water at 80°C for 24 h. Detailed Implementation

[0055] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0056] Unless otherwise specified, the materials and equipment involved in the following detailed embodiments are all conventional materials and equipment in the art and will not affect the technical effects of the present invention.

[0057] Example 1 This embodiment provides an integrated reinforced membrane for water electrolysis, a proton exchange membrane for water electrolysis, and a method for preparing the same. The preparation method includes the following steps: (1) Take 150 g of powdered short-side-chain perfluorosulfonic acid resin (IEC≈1.4 meq / g, model Aquivion) ® PW72S (manufacturer: Synesqo) was added to 850 g of an aqueous ethanol solution (ethanol to water mass ratio of 50:50), mechanically stirred at 50°C for 12 h, and filtered to obtain a short-chain perfluorosulfonic acid resin solution with a solid content of 15 wt%.

[0058] (2) The reinforcing fabric (polyetheretherketone mesh, Swiss SEFAR mesh 17-115X145 / 58, thickness 50 μm, unit area mass 17 g / m) is used. 2 The fabric (with an average porosity of 58%) was subjected to the following treatments: ultrasonic cleaning with acetone for 10 min, rinsing with deionized water 3 times, vacuum drying at 80℃ for 2 h, and treatment under oxygen plasma at a power of 100 W, a working pressure of 30 Pa, and a time of 5 min to obtain the treated reinforced fabric.

[0059] (3) The treated reinforcing fabric obtained in step (2) is spread flat on a polished stainless steel plate. The short-side chain perfluorosulfonic acid resin solution obtained in step (1) is uniformly cast onto the surface of the treated reinforcing fabric. A precision scraper with a gap of 600 μm is used to scrape the short-side chain perfluorosulfonic acid resin solution into the pores of the treated reinforcing fabric. Then, it is placed in a 60°C oven for pre-drying for 2 h, cooled, and the casting and scraping of the short-side chain perfluorosulfonic acid resin solution obtained in step (1) are repeated on the surface of the formed coating film. Then, it is placed in a 60°C oven for pre-drying for 2 h, and then heated to 120°C for drying for 1 h. Then, it is heat-treated at 160°C for 1 h to obtain an integrated reinforcing film for water electrolysis. The thickness is measured to be 85±3 μm using a micrometer.

[0060] (4) Cut the integrated reinforced membrane for water electrolysis obtained in step (3) into 5 cm × 5 cm pieces, immerse them in 0.5 mol / L sulfuric acid solution for 2 h to achieve protonation treatment, and then wash them 3 times with boiling deionized water until the pH of the washing solution is 6.5. Each washing time is 30 min to obtain the proton exchange membrane for water electrolysis.

[0061] Example 2 This embodiment provides an integrated reinforced membrane for water electrolysis and a proton exchange membrane for water electrolysis, as well as their preparation method. The difference between this embodiment and Embodiment 1 is that the reinforcing fabric (polyetheretherketone mesh, Swiss SEFAR mesh 17-115X145 / 58, thickness 50 μm, unit area mass 17 g / m²) is used. 2 The average porosity was 58%, which was replaced with a reinforcing fabric (polyphenylene sulfide mesh from Zhejiang Huapu Screening Co., Ltd., with a thickness of 63 μm and a unit area mass of 12 g / m²). 2 The average porosity was 40%. The integrated reinforced membrane for water electrolysis prepared in step (3) had a thickness of 88±3 μm as measured by a micrometer. Other conditions were the same as in Example 1.

[0062] Example 3 This embodiment provides an integrated reinforced membrane for water electrolysis and a proton exchange membrane for water electrolysis, as well as their preparation method. The difference between this embodiment and Embodiment 1 is that the reinforcing fabric (polyetheretherketone mesh, Swiss SEFAR mesh 17-115X145 / 58, thickness 50 μm, unit area mass 17 g / m²) is used. 2 The average porosity was 58%, which was replaced with a reinforcing fabric (a woven mesh of polyetheretherketone and polyphenylene sulfide, 60 μm thick and with a unit area mass of 18 g / m²). 2 The average porosity was 60%, the mass ratio of polyether ether ketone and polyphenylene sulfide was 1:1), and the integrated reinforced membrane for water electrolysis prepared in step (3) had a thickness of 92±4 μm measured by micrometer. Other conditions were the same as in Example 1.

[0063] Example 4 This embodiment provides an integrated reinforced membrane for water electrolysis and a proton exchange membrane for water electrolysis, and their preparation method. The difference between this embodiment and Embodiment 1 is that the casting amount of short-side chain perfluorosulfonic acid resin solution in step (3) is reduced, so that the thickness of the integrated reinforced membrane for water electrolysis obtained in step (3) is measured to be 62±3 μm using a micrometer. Other conditions are the same as in Embodiment 1.

[0064] Example 5 This embodiment provides an integrated reinforced membrane for water electrolysis and a proton exchange membrane for water electrolysis, as well as their preparation method. The difference between this embodiment and Embodiment 1 is that the reinforcing fabric (polyetheretherketone mesh, Swiss SEFAR mesh 17-115X145 / 58, thickness 50 μm, unit area mass 17 g / m²) is used. 2 The average porosity was 58%, which was replaced with a reinforcing fabric (polyetheretherketone mesh from Zhejiang Huapu Screening, 100 μm thick, with a unit area mass of 28 g / m²). 2(with an average porosity of 45%), in step (3), by repeating the casting, scraping, pre-drying, and drying steps, the casting amount of short-side chain perfluorosulfonic acid resin solution is increased, so that the thickness of the integrated reinforced membrane for water electrolysis prepared in step (3) is measured by a micrometer to be 143±5 μm. Other conditions are the same as in Example 1.

[0065] Example 6 This embodiment provides an integrated reinforced membrane for water electrolysis and a proton exchange membrane for water electrolysis, as well as their preparation method. The difference between this embodiment and Embodiment 1 is that the reinforcing fabric (polyetheretherketone mesh, Swiss SEFAR mesh 17-115X145 / 58, thickness 50 μm, unit area mass 17 g / m²) is used. 2 The average porosity was 58%, which was replaced with a reinforcing fabric (polyetheretherketone mesh from Zhejiang Huapu Screening, with a thickness of 250 μm and a unit area mass of 43 g / m²). 2 The average porosity is 38%. In step (3), the casting amount of short-side chain perfluorosulfonic acid resin solution is increased by repeating the casting, scraping, pre-drying and drying steps, so that the thickness of the integrated reinforced membrane for water electrolysis prepared in step (3) is 430±10 μm as measured by micrometer. Other conditions are the same as in Example 1.

[0066] Example 7 This embodiment provides an integrated reinforced membrane for water electrolysis, a proton exchange membrane for water electrolysis, and a method for preparing the same. The preparation method includes the following steps: (1) Take 100 g of powdered short-side-chain perfluorosulfonic acid resin (IEC≈1.4 meq / g, model Aquivion) ® PW72S (manufacturer: Synesqo) was added to 900 g of an aqueous ethanol solution (ethanol to water mass ratio of 50:50), mechanically stirred at 50°C for 12 h, and filtered to obtain a short-chain perfluorosulfonic acid resin solution with a solid content of 10%.

[0067] (2) The reinforcing fabric (polyetheretherketone mesh, Swiss SEFAR mesh 17-115X145 / 58, thickness 50 μm, unit area mass 17 g / m) is used. 2 The fabric (with an average porosity of 58%) was subjected to the following treatments: ultrasonic cleaning with acetone for 10 min, rinsing with deionized water 3 times, vacuum drying at 80℃ for 2 h, and treatment under oxygen plasma for 5 min at a power of 100 W and a working pressure of 30 Pa to obtain the treated reinforced fabric.

[0068] (3) The treated reinforcing fabric obtained in step (2) is spread flat on a polished stainless steel plate. The short-side chain perfluorosulfonic acid resin solution obtained in step (1) is uniformly cast onto the surface of the treated reinforcing fabric. A precision scraper with a gap of 500 μm is used to scrape the solution so that it completely penetrates the pores of the treated reinforcing fabric. Then, it is placed in a 60°C oven for pre-drying for 2 h. After cooling, the casting and scraping of the short-side chain perfluorosulfonic acid resin solution obtained in step (1) are repeated on the surface of the formed coating film. The film is then placed in a 60°C oven for pre-drying for 2 h. The above operation is repeated for a total of 3 times. Then, the temperature is raised to 120°C and dried for 1 h. Then, it is heat-treated at 120°C for 2 h to obtain an integrated reinforcing film for water electrolysis. The thickness is measured to be 75±3 μm using a micrometer.

[0069] (4) Cut the integrated reinforced membrane for water electrolysis obtained in step (3) into 5 cm × 5 cm pieces, immerse them in 0.3 mol / L sulfuric acid solution for 3 h to achieve protonation treatment, and then wash them 3 times with boiling deionized water for 30 min each time until the pH of the washing solution is 6, to obtain the proton exchange membrane for water electrolysis.

[0070] Example 8 This embodiment provides an integrated reinforced membrane for water electrolysis, a proton exchange membrane for water electrolysis, and a method for preparing the same. The preparation method includes the following steps: (1) Take 300 g of powdered short-side-chain perfluorosulfonic acid resin (IEC≈1.4 meq / g, model Aquivion) ® PW72S (manufacturer: Synensqo) was added to 700 g of an ethanol-water solution (ethanol to water mass ratio of 50:50), mechanically stirred at 50°C for 12 h, and filtered to obtain a short-chain perfluorosulfonic acid resin solution with a solid content of 30%.

[0071] (2) The reinforcing fabric (polyetheretherketone mesh, Swiss SEFAR mesh 17-115X145 / 58, thickness 50 μm, unit area mass 17 g / m) is used. 2 The fabric (with an average porosity of 58%) was subjected to the following treatments in sequence: ultrasonic cleaning with acetone for 10 min, rinsing with deionized water 3 times, vacuum drying at 80℃ for 2 h, and treatment under oxygen plasma for 5 min at a power of 100 W and a working pressure of 30 Pa to obtain the treated reinforced fabric.

[0072] (3) The treated reinforcing fabric obtained in step (2) is spread flat on a polished stainless steel plate. The short-side chain perfluorosulfonic acid resin solution obtained in step (1) is uniformly cast onto the surface of the treated reinforcing fabric. A precision scraper with a gap of 630 μm is used to scrape the short-side chain perfluorosulfonic acid resin solution into the pores of the treated reinforcing fabric. Then, it is placed in a 60℃ oven for pre-drying for 2 h, then heated to 120℃ for drying for 1 h, and then heat-treated at 160℃ for 1 h to obtain an integrated reinforcing membrane for water electrolysis. The thickness is measured to be 95±5 μm using a micrometer.

[0073] (4) Cut the integrated reinforced membrane for water electrolysis obtained in step (3) into 5 cm × 5 cm pieces, immerse them in 1 mol / L sulfuric acid solution for 1 h to achieve protonation treatment, and then wash them 3 times with boiling deionized water for 30 min each time until the pH of the washing solution is 7, to obtain the proton exchange membrane for water electrolysis.

[0074] Comparative Example 1 This comparative example provides an integrated reinforced membrane for water electrolysis and a proton exchange membrane for water electrolysis, as well as their preparation methods. The difference between this and Example 1 is that the reinforcing fabric (polyetheretherketone mesh, Swiss SEFAR mesh 17-115X145 / 58, thickness 50 μm, unit area mass 17 g / m²) is used. 2 The average porosity was 58%, which was replaced with a reinforcing fabric (stretched polytetrafluoroethylene mesh from Ningbo Changqi, with a thickness of 50 μm and a unit area mass of 15 g / m). 2 (The average porosity was 80%), and other conditions were the same as in Example 1.

[0075] Comparative Example 2 This comparative example provides a proton exchange membrane for water electrolysis, specifically a DuPont Nafion 115 perfluorosulfonic acid ion exchange membrane with a thickness of 127 μm.

[0076] Comparative Example 3 This comparative example provides a proton exchange membrane for water electrolysis and its preparation method. The preparation method of the proton exchange membrane for water electrolysis includes the following steps: applying a short-chain perfluorosulfonic acid resin (IEC≈1.4 meq / g, model Aquivion)... ®PW72S (manufactured by Synesqo) was mixed with an ethanol-water solution (ethanol and water in a mass ratio of 50:50) to form a short-chain perfluorosulfonic acid resin solution with a solid content of 15 wt%. The solution was then cast onto a flat substrate and pre-dried at 60°C for 2 h. This process was repeated twice, followed by drying at 120°C for 1 h and heat treatment at 160°C for 1 h, to obtain a film with a thickness of 85±3 μm. The film was then cut into 5 cm×5 cm sheets and immersed in a 0.5 mol / L sulfuric acid solution for 2 h to achieve protonation treatment. The sheets were then washed three times with boiling deionized water until the pH of the washing solution reached 6.5, with each washing lasting 30 min, to obtain the proton exchange membrane for water electrolysis.

[0077] The integrated reinforced membrane and proton exchange membrane for water electrolysis provided in the above embodiments and comparative examples were subjected to the following performance tests.

[0078] (1) Sheet resistance (ASR): The proton exchange membrane used for water electrolysis was tested at 80°C under full hydration conditions (saturated with deionized water) using a four-electrode electrochemical impedance spectroscopy device.

[0079] (2) Wet tensile properties: In accordance with ASTM D882 standard, at 25℃ and 100% relative humidity, a sample of 10 mm × 50 mm was prepared for the proton exchange membrane used for water electrolysis. The tensile rate was 50 mm / min, and the tensile strength, elongation at break and Young's modulus were tested.

[0080] (3) Wet-state dimensional stability: The proton exchange membrane used for water electrolysis was placed in a test environment of 25℃ and 65%RH for 24 h and then cut into initial dry membrane samples of 30 mm × 30 mm. Then, it was soaked in deionized water at 80℃ for 24 h. The expansion rate in the length and width directions after soaking was measured respectively, and the average value was taken to obtain the dimensional change rate of the proton exchange membrane used for water electrolysis.

[0081] Thickness retention rate: The proton exchange membrane used for water electrolysis was placed in a test environment of 25℃ and 65%RH for 24 hours and then cut into 30 mm × 30 mm initial dry membrane samples. After soaking in deionized water at 80℃ for 24 hours, the samples were removed, surface moisture was removed, and the thickness was measured under the same compression conditions (0.5 MPa). The thickness retention rate was calculated by comparing the thickness with the initial dry thickness. Thickness retention rate = (initial dry thickness / thickness after soaking) × 100%.

[0082] (4) Performance of a single water electrolysis cell: The proton exchange membrane used for water electrolysis was assembled into a 5cm... 2A single water electrolysis cell with effective area, wherein the anode is an IrO2 catalyst layer (Ir loading is 1.5 mg / cm²). 2 The cathode is a Pt / C catalyst layer (Pt loading is 0.5 mg / cm³). 2 The operating temperature is 80℃, the cathode (hydrogen side) pressure is 1.0MPa (G), and the anode (oxygen side) pressure is 0.2MPa (G).

[0083] Steady-state cell voltage: The tested water electrolysis single cell was 1.0 A / cm. 2 Steady-state battery voltage at current density.

[0084] Stability test: The prepared water electrolysis single cell was tested at 1.5 A / cm. 2 The battery voltage decay was measured after 1000 h of continuous operation at 80℃, cathode pressure of 1.0 MPa (G), and anode pressure of 0.2 MPa (G), and the proton exchange membrane used for water electrolysis was observed to show visible cracks or mechanical damage.

[0085] The test results are shown in Tables 1 and 2.

[0086] Table 1 Table 2 According to the test results in Tables 1 and 2, the proton exchange membranes for water electrolysis provided in Examples 1-8 have a sheet resistance ≤ 80 mΩ·cm under conditions of 80°C and full hydration of deionized water. 2 The proton exchange membrane used for water electrolysis exhibits a tensile strength ≥25 MPa at 25°C and 100% relative humidity, and a dimensional change rate ≤20% after immersion in deionized water at 80°C for 24 h, demonstrating low sheet resistance, high wet mechanical strength, and good dimensional stability.

[0087] Compared with Example 1, if the thickness of the integrated reinforcing membrane used for water electrolysis is too thin (Example 4), the wet tensile strength will decrease and the dimensional stability will deteriorate because the reinforcing fabric is not fully coated with short side chain perfluorosulfonic acid resin and the local continuous phase is insufficient.

[0088] Compared to Example 1, if the thickness of the integrated reinforced membrane used for water electrolysis is thicker (Example 5) or (Example 6), although the mechanical properties and stability are further improved, the sheet resistance increases significantly, resulting in an increase in the electrolysis voltage.

[0089] Compared to Example 1, the sheet resistivity of the proton exchange membrane for water electrolysis provided in Comparative Example 1 increased by approximately 32%, the tensile strength at 25°C and 100% relative humidity decreased by approximately 29%, and its thickness retention rate under the same compressive stress and hydration conditions was approximately 12% lower than that of Example 1. These results indicate that under the high-temperature and high-hydration conditions of proton exchange membrane water electrolysis, the polytetrafluoroethylene (PTFE) mesh is difficult to form a thermal, moisture, and mechanical synergistic constraint structure with the short-side-chain perfluorosulfonic acid resin as in Example 1, thus making it difficult to simultaneously meet the comprehensive performance requirements of low ohmic impedance and high wet mechanical stability.

[0090] Compared with Comparative Example 2, the surface resistance of the proton exchange membrane for water electrolysis prepared in Example 1 is lower under the same conditions, and the water electrolysis single cell prepared has a lower battery voltage and lower energy consumption.

[0091] Compared with Comparative Example 3, the proton exchange membrane prepared in Example 1 for water electrolysis showed significantly improved tensile strength and significantly reduced dimensional change rate under conditions of 25°C and 100% relative humidity.

[0092] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An integrated reinforced membrane for water electrolysis, characterized in that, The integrated reinforced membrane for water electrolysis includes a reinforcing fabric and a short-chain perfluorosulfonic acid resin covering the reinforcing fabric; The reinforcing fabric comprises an aromatic polymer mesh.

2. The integrated reinforced membrane for water electrolysis according to claim 1, characterized in that, The thickness of the aromatic polymer mesh is 10~100 μm, more preferably 30~90 μm, and even more preferably 40~70 μm; Preferably, the aromatic polymer mesh has a unit area mass of 5~40 g / m². 2 More preferably, it is 10~20 g / m 2 ; Preferably, the porosity of the aromatic polymer mesh is 20% to 90%, more preferably 50% to 70%; Preferably, the material of the aromatic polymer mesh includes aromatic polymers; Preferably, the aromatic polymer comprises polyetheretherketone and / or polyphenylene sulfide; Preferably, the aromatic polymer mesh is a treated aromatic polymer mesh; Preferably, the process includes cleaning and surface activation treatment.

3. The integrated reinforced membrane for water electrolysis according to claim 1 or 2, characterized in that, The short-side-chain perfluorosulfonic acid resin has an ion exchange capacity of 0.8~1.5 meq / g, more preferably 1.2~1.4 meq / g; Preferably, the thickness of the integrated reinforced membrane for water electrolysis is 20~500 μm, more preferably 50~150 μm, and even more preferably 70~100 μm.

4. A method for preparing an integrated reinforced membrane for water electrolysis as described in any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: impregnating the reinforcing fabric with a short-side-chain perfluorosulfonic acid resin solution, pre-drying, forming a coating film on the reinforcing fabric, optionally repeating the above steps to form at least two coating films on the reinforcing fabric, drying, and heat treatment to obtain the integrated reinforcing film for water electrolysis.

5. The preparation method according to claim 4, characterized in that, The method of impregnating the reinforcing fabric with a short-side-chain perfluorosulfonic acid resin solution includes using a solution casting method to allow the short-side-chain perfluorosulfonic acid resin solution to enter the interior of the reinforcing fabric and form a continuous phase coating on the reinforcing fabric. Preferably, the short-side-chain perfluorosulfonic acid resin solution comprises a short-side-chain perfluorosulfonic acid resin and a polar solvent; Preferably, the polar solvent includes any one or a combination of at least two of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, alcohol solvents or water; Preferably, the solid content of the short-side-chain perfluorosulfonic acid resin solution is 5wt%~30wt%; Preferably, the pre-drying temperature is 40~80℃, and the pre-drying time is 0.5~5 h; Preferably, the drying temperature is 80℃~120℃, and the drying time is 0.5~5 h; Preferably, the temperature of the heat treatment is 50~220℃, more preferably 120~200℃; Preferably, the heat treatment time is 0.5 to 2 hours.

6. A proton exchange membrane for water electrolysis, characterized in that, The proton exchange membrane for water electrolysis is prepared by protonation treatment of the integrated reinforced membrane for water electrolysis as described in any one of claims 1 to 3.

7. The proton exchange membrane for water electrolysis according to claim 6, characterized in that, The protonation treatment includes protonation using an acid solution; Preferably, the acid solution includes a sulfuric acid solution; Preferably, the concentration of the sulfuric acid solution is 0.1~1.0 mol / L; Preferably, the protonation treatment further includes washing until the pH is 6-7; Preferably, the proton exchange membrane used for water electrolysis has a sheet resistance ≤ 80 mΩ·cm under conditions of 80°C and full hydration of deionized water. 2 More preferably ≤50 mΩ·cm 2 ; Preferably, the proton exchange membrane used for water electrolysis has a tensile strength of ≥25 MPa under conditions of 25°C and 100% relative humidity, and more preferably ≥30 MPa. Preferably, the dimensional change rate of the proton exchange membrane used for water electrolysis after immersion in deionized water at 80°C for 24 h is ≤20%, and more preferably ≤15%.

8. A water electrolysis device, characterized in that, The water electrolysis device includes an anode chamber, a cathode chamber, and a proton exchange membrane for water electrolysis as described in claim 6 or 7, disposed between the anode chamber and the cathode chamber.

9. The application of any one of the integrated reinforced membrane for water electrolysis as described in any one of claims 1 to 3, the proton exchange membrane for water electrolysis as described in claim 6 or 7, or the water electrolysis device as described in claim 8 in water electrolysis hydrogen production.

10. The application according to claim 9, characterized in that, The temperature for hydrogen production via water electrolysis is 80~120℃; Preferably, the cathode pressure for hydrogen production by water electrolysis is 0.5~10.0 MPa(G), and the anode pressure is 0.1~0.5 MPa(G); Preferably, the cathode pressure for hydrogen production by water electrolysis is 1.0~5.0 MPa(G), and the anode pressure is 0.1~0.3 MPa(G).

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