Composite diaphragm for hydrogen production by alkaline electrolysis of water and preparation method and application thereof

Abstract

The application relates to a composite diaphragm for hydrogen production by alkaline electrolysis of water and a preparation method and application thereof, the composite diaphragm comprising a support substrate, and mixed matrix layers arranged on both sides of the support substrate, wherein the mixed matrix layers comprise a mixture of a functional polymer resin and a thermoplastic resin, the mixed matrix layers are porous structures, and the functional polymer resin is orderly arranged on the outer surface of the pores of the mixed matrix layers. The preparation method is as follows: preparing a casting solution; coating the casting solution on both sides of the support substrate; phase inversion; cleaning and preservation. Compared with the prior art, the phase separation step of the mixed matrix layer is regulated in the application, so that the functional polymer resin is distributed on the pore surface of the composite diaphragm, the composite diaphragm has excellent stability, gas tightness and OH ‑ conductivity, and the film preparation cost is low.

Description

Technical Field

[0001] This invention relates to the field of membrane technology for alkaline water electrolysis hydrogen production, and in particular to a composite membrane for alkaline water electrolysis hydrogen production, its preparation method, and its application. Background Technology

[0002] Hydrogen, as an ideal energy carrier, possesses advantages such as high calorific value, high energy density, and cleanliness, making it crucial for achieving a clean energy transition, optimizing the energy structure, promoting deep industrial decarbonization, and facilitating the consumption and utilization of renewable energy. As the most promising hydrogen production technology of the 21st century, water electrolysis is considered the only source of green hydrogen. Among these technologies, alkaline water electrolysis (AWE) is considered the most commercially viable option for large-scale hydrogen production due to its lower investment costs and mature technology.

[0003] The diaphragm is one of the core materials of the AWE diaphragm electrolyzer. When the electrolyzer is in operation, OH... - Hydrogen and oxygen produced during electrolysis move from the cathode through the membrane to the anode, while the membrane separates them. To prevent hydrogen-oxygen cross-contamination, the membrane thickness is limited. Mainstream polyphenylene sulfide (PPS) woven fabrics are typically over 800 μm thick, while third-generation alkaline water membranes (organic-inorganic composite membranes) are around 500 μm thick, ten times thicker than anion exchange membranes. Increased thickness can lead to OH-... - The increased transmission resistance manifests as a higher electrolysis voltage, thus increasing the OH content of the diaphragm. - Conductivity is key to reducing AWE energy consumption.

[0004] Organic-inorganic composite membranes, primarily based on Agfa's Zirfon Perl series, represent the greatest potential for alkaline water membranes to combine airtightness and electrochemical performance. These membranes use polysulfone as the film-forming material, with zirconium oxide providing hydrophilicity and a PPS mesh substrate providing mechanical strength, and are prepared using a solvent-inducible phase separation (NIPS) process. Building upon this, CN118147702A, starting from the physicochemical properties of the inorganic filler itself, achieves a composite membrane with lower sheet resistivity and higher uniformity by controlling the particle size and mass ratio of the inorganic filler; CN115125582A introduces layered bimetallic hydroxide (LDH), utilizing the hydrophilicity of LDH and its good intrinsic OH content... - Conductivity is improved, thereby reducing the surface resistance of the organic-inorganic composite diaphragm.

[0005] Therefore, regulating the inorganic filler is crucial for improving the OH content of the diaphragm. -While polysulfone (PS) offers an effective solution for improving conductivity, its excellent stability leads to poor interfacial compatibility with inorganic fillers. Furthermore, the significantly higher content of inorganic fillers (70-90 wt%) compared to PSA (10-30 wt%) results in powder shedding during transportation and use of the organic-inorganic composite membrane, leading to poor membrane stability and short lifespan. CN117230484A and CN118581518A propose adding a hydrophilic coating to the base membrane surface to encapsulate the inorganic fillers without affecting the sheet resistivity, thereby improving the stability of the organic-inorganic composite membrane. However, in membrane production, from the perspectives of materials, processes, and equipment, adding an extra coating increases production costs and diminishes its competitive advantage. Summary of the Invention

[0006] The purpose of this invention is to provide a composite membrane for alkaline water electrolysis to produce hydrogen, its preparation method, and its application. The prepared composite membrane exhibits excellent stability, airtightness, and OH- resistant properties. - Conductivity.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] In a first aspect, the present invention provides a composite membrane for alkaline water electrolysis to produce hydrogen, comprising a supporting substrate, wherein a mixed matrix layer is disposed on both sides of the supporting substrate, the mixed matrix layer comprising a mixture of functional polymer resin and thermoplastic resin.

[0009] Preferably, the mixed matrix layer has a porous structure with a pore size of 1-100 nm and a porosity of 30-70%.

[0010] Preferably, the thickness of the mixed matrix layer is 30-300 μm, and the thickness of the supporting substrate is 70-300 μm.

[0011] Preferably, in the mixed matrix layer, the functional polymer resin is arranged in an orderly manner on the outer surface of the pores of the mixed matrix layer.

[0012] In this invention, the ordered arrangement refers to the functional polymer resin being distributed relatively concentratedly on the surface of the pores, rather than being uniformly distributed within the mixed matrix layer.

[0013] Preferably, the functionality of the functional polymer resin refers to its hydrophilicity and ability to conduct hydroxide ions, its stability in alkaline solutions, its film-forming ability, and its solubility in organic solvents.

[0014] Preferably, the functional polymer resin includes, but is not limited to, one or more of perfluorosulfonic acid resin, quaternized polysulfone, sulfonated polysulfone, quaternized polyphenylene ether, quaternized polybenzimidazole, polyarylpiperidine, and polyarylquinine.

[0015] Preferably, the thermoplastic resin includes, but is not limited to, one or more of polysulfone, polyethersulfone, polyetheretherketone, polyimide, and polyetherimide.

[0016] Preferably, the supporting substrate includes any one of mesh, porous membrane, nonwoven fabric, and woven fabric, and its material includes, but is not limited to, one or more of polyphenylene sulfide, polyethylene, polypropylene, polytetrafluoroethylene, polyetheretherketone, and polyimide.

[0017] Secondly, the present invention provides a method for preparing the composite membrane for alkaline water electrolysis to produce hydrogen, comprising the following steps:

[0018] S1: Thermoplastic resin and functional polymer resin are dissolved in an organic solvent and stirred to prepare a casting solution;

[0019] S2: Apply casting solution to both sides of the supporting substrate;

[0020] S3: Phase transformation;

[0021] S4: Clean and store.

[0022] Preferably, step S1 specifically includes the following steps: at 70-90°C, the thermoplastic resin and functional polymer resin are dissolved in an organic solvent and stirred at a speed of 300-1000 rpm for more than 4 hours to ensure that the polymer chains are fully expanded. The homogeneous solution after the polymer is completely dissolved is the casting solution.

[0023] Preferably, in step S1, the amount of the functional polymer resin added is 1-50 wt% of the thermoplastic resin, and the content of the thermoplastic resin in the organic solvent is 5-40 wt%.

[0024] More preferably, in step S1, the amount of the functional polymer resin added is 10 wt% of the thermoplastic resin.

[0025] In step S1 of this invention, the optimal amount of the functional polymer resin to be added needs to take into account factors such as whether the casting solution is easy to coat and material costs.

[0026] Preferably, in step S1, the organic solvent includes, but is not limited to, one or more of N-methyl-2-pyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, formamide, and N,N-dimethylacetamide.

[0027] Preferably, step S2 includes the following steps: at 20-27°C and 50-70% relative humidity, a casting liquid is applied to the left and right sides of the support substrate by a scraper or a coating head.

[0028] Preferably, step S3 includes the following steps: immersing the support substrate coated with casting solution in non-solvent solutions at low temperature, room temperature, and high temperature in sequence, with each immersion time not less than 30 minutes, and removing it after the organic solvent has been completely replaced.

[0029] Preferably, in step S3, the non-solvent includes, but is not limited to, one or more of deionized water, n-propanol, isopropanol, and ethanol.

[0030] Preferably, in step S3, the low temperature is -15 to 15°C, the normal temperature is 15 to 40°C, and the high temperature is 40 to 100°C.

[0031] More preferably, in step S3, when the non-solvent is deionized water, the lowest temperature of deionized water is 0°C. If further cooling is required, other non-solvents such as ethanol can be added.

[0032] More preferably, in step S3, the non-solvent at high temperature is usually deionized water.

[0033] More preferably, in step S3, the soaking time is 1 hour each time.

[0034] Preferably, step S4 includes the following steps: cleaning the composite membrane with deionized water, cutting it to a suitable size, and storing it in deionized water.

[0035] More preferably, in step S4, the deionized water used for cleaning and storage is at room temperature.

[0036] Thirdly, the present invention also provides an application of the composite membrane for alkaline water electrolysis hydrogen production in alkaline water electrolysis hydrogen production.

[0037] More preferably, the preparation method of the composite membrane for alkaline water electrolysis to produce hydrogen includes the following steps:

[0038] S1: At 80℃, thermoplastic resin and functional polymer resin are added in batches to an organic solvent and mechanically stirred for more than 4 hours to ensure that the polymer chains are fully expanded. The homogeneous solution after the polymer is completely dissolved is the casting solution.

[0039] S2: At 25℃ and 60% relative humidity, a dry and clean support substrate is tightened using a clamp, and casting liquid is applied to the left and right sides of the support substrate by a scraper or coating head.

[0040] S3: Immerse the coated support substrate sequentially in low temperature, room temperature, and high temperature non-solvent solutions, with each immersion time being 1 hour. After the organic solvent is completely replaced, remove the mixed matrix membrane.

[0041] S4: Clean the diaphragm with deionized water, cut it to the appropriate size, and store it in deionized water.

[0042] This invention proposes a composite membrane for alkaline water electrolysis to produce hydrogen, which utilizes alkali-resistant, hydrophilic membranes and possesses OH- ions. - Functional polymer resins with high conductivity replace traditional inorganic fillers. Utilizing the different interactions between various polymers and solvents / non-solvents, segregation of the functional polymer resins is induced during the NIPS process (i.e., the phase inversion process of this invention), causing them to arrange themselves in an orderly manner on the surface of the porous composite membrane channels. Through ion exchange and promoting the diffusion of hydrated ions, the functional groups of the functional polymer resins themselves can directly or indirectly interact with OH groups within the channels. - Interactions accelerate the production of OH groups within the membrane. - Conductivity is improved, enabling the functionalization of porous structures. Furthermore, the bonding effect between two polymers with relatively similar polarities is far better than that between a polymer and an inorganic filler. Therefore, using functional polymer resins fundamentally solves the powder shedding problem of organic-inorganic composite membranes and is a good way to improve the stability of alkaline water membranes.

[0043] This invention, based on the different solubilities of two types of polymers in solvents and non-solvents, regulates the phase separation step (i.e., the phase transformation step of this invention) of the mixed matrix layer. This causes the thermoplastic resin to exhibit a solid-liquid phase separation tendency first, while the functional polymer resin, under the combined action of solvents and non-solvents, moves towards the depleted phase region of the thermoplastic resin, ultimately forming a porous outer surface. The functional polymer resin used in this invention has excellent hydrophilicity. When the composite film with a porous structure prepared in this invention is placed in an electrolyte (30wt% KOH aqueous solution), the functional polymer resin swells on the pore surface of the mixed matrix layer, resulting in a smaller pore size and thus improving the airtightness of the porous membrane. Furthermore, the functional resin has the ability to conduct hydroxide ions, minimizing the negative impact of pore size reduction on hydroxide ion conduction. Therefore, this invention, with good OH... - It has excellent conductivity and airtightness.

[0044] In addition, traditional composite membranes require the addition of inorganic fillers to improve hydrophilicity and enhance hydroxide ion conductivity. However, during the assembly or operation of the electrolytic cell, due to the poor compatibility between inorganic fillers and polymers, inorganic fillers often detach, leading to a decrease in hydroxide ion conductivity. At the same time, the detached inorganic fillers can enlarge the pores and reduce airtightness. This invention uses a functional polymer resin with hydroxide ion conductivity to replace the inorganic filler, ensuring hydroxide ion conductivity while eliminating the possibility of powder shedding, thus improving stability.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) This invention prepares a composite membrane for alkaline water electrolysis to produce hydrogen by setting a mixed matrix layer on both sides of a supporting substrate. The mixed matrix layer comprises a mixture of functional polymer resin and thermoplastic resin. The composite membrane has excellent stability, air tightness, and OH... - Conductivity.

[0047] (2) The present invention uses a functional polymer resin with better compatibility to replace the hydrophilic inorganic filler (such as zirconium oxide) in the traditional organic-inorganic composite membrane for alkaline water electrolysis hydrogen production. This can avoid the problem of membrane failure caused by inorganic filler shedding, and eliminate the possibility of powder shedding while ensuring the conduction of hydroxide ions, thereby improving stability.

[0048] (3) The mixed matrix layer proposed in this invention has a porous structure. By controlling the phase separation step of the mixed matrix layer, the functional polymer resin is distributed on the pore surface of the composite membrane. The abundant functional groups of the functional polymer resin promote the OH- in the electrolyte. - Its rapid movement and hydrate movement greatly enhance the OH content of the composite membrane. - Conductivity.

[0049] (4) The functional polymer resin used in this invention has excellent hydrophilicity and is easy to swell in alkaline solution, which realizes the positive effect of pore shrinkage and airtightness improvement of the diaphragm under working conditions.

[0050] (5) The preparation method of the present invention improves the utilization rate of functional polymer resin and reduces the membrane production cost of alkaline water membrane.

[0051] (6) The method of the present invention is simple and easy to implement, safe to operate, and easy to industrialize.

[0052] (7) The method for preparing the composite membrane for alkaline water electrolysis to produce hydrogen proposed in this invention can realize the specific arrangement of different polymers in the porous membrane, providing a new idea for the structural design of composite membranes with mixed matrix layers. Attached Figure Description

[0053] Figure 1 This is a flowchart of the preparation method of the present invention;

[0054] Figure 2 This is a schematic diagram of the structure of the present invention (in the figure: 1-thermoplastic resin; 2-functional polymer resin). Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0056] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0057] A composite membrane for alkaline water electrolysis to produce hydrogen includes a supporting substrate, on both sides of which are mixed matrix layers. The mixed matrix layers comprise a mixture of functional polymer resin 2 and thermoplastic resin 1. The mixed matrix layers have a porous structure with pore sizes of 1-100 nm and a porosity of 30-70%. The functional polymer resin 2 is arranged in an orderly fashion on the outer surface of the pores in the mixed matrix layers.

[0058] Its preparation method is as follows:

[0059] S1: Thermoplastic resin and functional polymer resin are dissolved in an organic solvent and stirred to prepare a casting solution;

[0060] S2: Apply casting solution to both sides of the supporting substrate;

[0061] S3: Phase transformation;

[0062] S4: Clean and store.

[0063] Example 1

[0064] A composite membrane for alkaline water electrolysis to produce hydrogen is prepared as follows: At 80°C, 20g of polysulfone and 1g of sulfonated polysulfone are placed in 85g of N-methyl-2-pyrrolidone and mechanically stirred for 4 hours to obtain a casting solution; at 25°C and 60% relative humidity, a 50-mesh, 280μm thick polyphenylene sulfide woven mesh is stretched taut using a clamp, and 300μm scrapers are fixed on both sides. After the casting solution fills the gaps between the scrapers, the clamp is pushed downwards at a speed of 0.2m / min; the entire clamp is sequentially immersed in isopropanol at 5°C, deionized water at 25°C, and deionized water at 90°C, each immersion time being 1 hour; the entire clamp is removed, the composite membrane is taken out and its surface is rinsed with deionized water, and it is cut to a suitable size and stored in deionized water for convenient subsequent testing and use.

[0065] Example 2

[0066] A composite membrane for alkaline water electrolysis to produce hydrogen is prepared as follows: At 80°C, 20g of polysulfone and 2g of sulfonated polysulfone are placed in 85g of N-methyl-2-pyrrolidone and mechanically stirred for 4 hours to obtain a casting solution; at 25°C and 60% relative humidity, a 50-mesh, 280μm thick polyphenylene sulfide woven mesh is stretched taut using a clamp, and 300μm scrapers are fixed on both sides. After the casting solution fills the gaps between the scrapers, the clamp is pushed downwards at a speed of 0.2m / min; the entire clamp is sequentially immersed in isopropanol at 5°C, deionized water at 25°C, and deionized water at 90°C, each immersion time being 1 hour; the entire clamp is removed, the composite membrane is taken out and its surface is rinsed with deionized water, and it is cut to a suitable size and stored in deionized water for convenient subsequent testing and use.

[0067] Example 3

[0068] A composite membrane for alkaline water electrolysis to produce hydrogen is prepared as follows: At 80°C, 20g of polysulfone and 5g of sulfonated polysulfone are placed in 85g of N-methyl-2-pyrrolidone and mechanically stirred for 4 hours to obtain a casting solution; at 25°C and 60% relative humidity, a 50-mesh, 280μm thick polyphenylene sulfide woven mesh is stretched taut using a clamp, and 300μm scrapers are fixed on both sides. After the casting solution fills the gaps between the scrapers, the clamp is pushed downwards at a speed of 0.2m / min; the entire clamp is sequentially immersed in isopropanol at 5°C, deionized water at 25°C, and deionized water at 90°C, each immersion time being 1 hour; the entire clamp is removed, the composite membrane is taken out and its surface is rinsed with deionized water, and it is cut to a suitable size and stored in deionized water for convenient subsequent testing and use.

[0069] Example 4

[0070] A composite membrane for alkaline water electrolysis to produce hydrogen is prepared as follows: At 80°C, 20g of polysulfone and 2g of quaternized polysulfone are placed in 85g of N-methyl-2-pyrrolidone and mechanically stirred for 6 hours to obtain a casting solution; at 25°C and 60% relative humidity, a 50-mesh, 280μm thick polyphenylene sulfide woven mesh is stretched taut using a clamp, and 300μm scrapers are fixed on both sides. After the casting solution fills the gaps between the scrapers, the clamp is pushed downwards at a speed of 0.2m / min; the entire clamp is sequentially immersed in deionized water at 5°C, 25°C, and 90°C for 1 hour each time; the entire clamp is removed, the composite membrane is taken out and its surface is rinsed with deionized water, and it is cut to a suitable size and stored in deionized water for convenient subsequent testing and use.

[0071] Example 5

[0072] A composite membrane for alkaline water electrolysis to produce hydrogen is prepared as follows: At 80°C, 20g of polysulfone and 5g of quaternized polysulfone are placed in 85g of N-methyl-2-pyrrolidone and mechanically stirred for 6 hours to obtain a casting solution; at 25°C and 60% relative humidity, a 50-mesh, 280μm thick polyphenylene sulfide woven mesh is stretched taut using a clamp, and 300μm scrapers are fixed on both sides. After the casting solution fills the gaps between the scrapers, the clamp is pushed downwards at a speed of 0.2m / min; the entire clamp is sequentially immersed in deionized water at 5°C, 25°C, and 90°C for 1 hour each time; the entire clamp is removed, the composite membrane is taken out and its surface is rinsed with deionized water, and it is cut to a suitable size and stored in deionized water for convenient subsequent testing and use.

[0073] Comparative Example 1

[0074] A commercially available organic-inorganic composite membrane product, model number Zirfon PERL UTP 500.

[0075] Comparative Example 2

[0076] Pure polysulfone coated alkaline water separator.

[0077] OH of Comparative Examples 1-2 and Examples 1-5 - Conductivity and airtightness were tested, including OH. - The test conditions for conductivity were: a two-electrode system, a temperature of 20℃, an electrolyte of 30wt% KOH solution, and electrodes made of 20-mesh, 300μm thick nickel mesh. The test conditions for airtightness were: the test method was the immersion pressure method, a temperature of 20℃, an immersion solution of anhydrous ethanol, and nitrogen displacement. The results are shown in Table 1.

[0078] Table 1. OH content of Comparative Examples 1-2 and Examples 1-5 - Conductivity and airtightness

[0079]

[0080] Table 1 shows the OH content of Comparative Examples 1-2 and Examples 1-5. - Conductivity and airtightness test data show that as the amount of functional polymer resin added increases, the sheet resistance of the diaphragm gradually decreases, while the bubble point pressure gradually increases, demonstrating the electrochemical performance of the diaphragm (OH). - Both conductivity and air tightness are significantly improved, even surpassing the commercially available alkaline water organic-inorganic composite membrane representative—Zirfon PERL UTP 500 (Comparative Example 1).

[0081] The porosity of Comparative Examples 1-2 and Examples 1-5 was tested using a gravimetric method, with anhydrous ethanol and deionized water as the impregnating solutions, respectively. The test results are shown in Table 2. Anhydrous ethanol had no swelling effect on polysulfone, sulfonated polysulfone, and quaternized polysulfone. However, when the impregnating solution was changed to deionized water, the porosity of Examples 1-5 decreased significantly. This demonstrates that the functional polymer resin swells on the pore surface of the mixed matrix layer, resulting in a smaller pore size and thus improving the airtightness of the porous composite membrane prepared by this invention.

[0082] Table 2 Porosity of Comparative Examples 1-2 and Examples 1-5

[0083]

[0084] The powder shedding rate of Comparative Example 1 and Examples 1-5 was tested using ultrasonic powder shedding tests. The ultrasonic powder shedding test conditions were: temperature 80℃, ultrasonic frequency 40kHz, ultrasonic time 1 hour, and immersion solution 30wt% KOH solution. No alkaline residue was found in the dry films after the tests. The results are shown in Table 3.

[0085] Table 3. Powder shedding rate of Comparative Example 1 and Examples 1-5

[0086]

[0087] Table 3 shows the powder shedding rate of Comparative Example 1 and Examples 1-5. It can be seen that the composite diaphragm of the present invention did not experience powder shedding, that is, the weight did not change significantly after ultrasonication, which effectively solved the powder shedding problem of organic-inorganic composite diaphragms and improved the stability of alkaline water diaphragms.

[0088] Table 4. Electrochemical performance of Comparative Examples 1-2 and Examples 1-5 as tested in actual tanks.

[0089]

[0090]

[0091] The electrochemical performance of Comparative Examples 1-2 and Examples 1-5 was tested in actual electrolytic cells under the following conditions: electrolytic cell temperature 90℃, both anode and cathode were ordinary nickel mesh, electrolyte was 30wt% KOH solution, flow rate was 500ml / min, and liquid was introduced from both sides. The test results are shown in Table 4. It can be seen that the mixed matrix layer with added functional polymer resin improved electrochemical performance while enhancing airtightness. Furthermore, the electrochemical performance of Examples 3 and 5 far exceeded that of commercial alkaline water organic-inorganic composite membranes, matching the data in Table 1.

[0092] In summary, this invention provides a composite membrane for alkaline water electrolysis to produce hydrogen, its preparation method, and its application. By setting a porous mixed matrix layer composed of functional polymer resin and thermoplastic resin on a supporting substrate, the OH content is improved. - Conductivity, stability, and airtightness.

[0093] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A composite membrane for alkaline water electrolysis to produce hydrogen, characterized in that, It includes a support substrate, and a mixed matrix layer is provided on both sides of the support substrate. The mixed matrix layer is a mixture of functional polymer resin and thermoplastic resin. The functional polymer resin is selected from one or more of perfluorosulfonic acid resin, quaternized polysulfone, sulfonated polysulfone, quaternized polyphenylene ether, quaternized polybenzimidazole, polyarylpiperidine, and polyarylquinine. The thermoplastic resin is selected from one or more of polysulfone, polyethersulfone, polyetheretherketone, polyimide, and polyetherimide; The supporting substrate is selected from any one of mesh, porous membrane, non-woven fabric, and woven fabric, and its material includes one or more of polyphenylene sulfide, polyethylene, polypropylene, polytetrafluoroethylene, polyetheretherketone, and polyimide.

2. The composite membrane for alkaline water electrolysis to produce hydrogen according to claim 1, characterized in that, The hybrid matrix layer has a porous structure with a pore size of 1-100 nm and a porosity of 30-70%.

3. The composite membrane for alkaline water electrolysis to produce hydrogen according to claim 1, characterized in that, The functional polymer resins are arranged in an orderly manner on the outer surface of the pores of the mixed matrix layer.

4. A method for preparing a composite membrane for alkaline water electrolysis to produce hydrogen as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1: Thermoplastic resin and functional polymer resin are dissolved in an organic solvent and stirred to prepare a casting solution; S2: Apply casting solution to both sides of the supporting substrate; S3: Phase transformation; S4: Clean and store.

5. The method for preparing a composite membrane for alkaline water electrolysis to produce hydrogen according to claim 4, characterized in that, Step S1 specifically includes the following steps: at 70~90℃, thermoplastic resin and functional polymer resin are dissolved in an organic solvent and stirred at a speed of 300-1000 rpm for more than 4 hours to prepare the casting solution.

6. The method for preparing a composite membrane for alkaline water electrolysis to produce hydrogen according to claim 4, characterized in that, In step S1, the amount of the functional polymer resin added is 1-50 wt% of the thermoplastic resin, and the content of the thermoplastic resin in the casting solution is 5-40 wt%; the organic solvent is selected from one or more of N-methyl-2-pyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, formamide, and N,N-dimethylacetamide.

7. The method for preparing a composite membrane for alkaline water electrolysis to produce hydrogen according to claim 4, characterized in that, Step S3 includes the following steps: The support substrate coated with casting solution is sequentially immersed in non-solvent solutions at low temperature, room temperature, and high temperature, with each immersion time not less than 30 minutes, and removed after the organic solvent is completely replaced.

8. The method for preparing a composite membrane for alkaline water electrolysis to produce hydrogen according to claim 7, characterized in that, In step S3, the non-solvent is selected from one or more of deionized water, n-propanol, isopropanol, and ethanol; the low temperature is -15 to 15°C, the normal temperature is 15 to 40°C, and the high temperature is 40 to 100°C.

9. The application of a composite diaphragm for alkaline water electrolysis hydrogen production as described in any one of claims 1-3 in alkaline water electrolysis hydrogen production.

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