Alkaline electrolytic water hydrogen production diaphragm with asymmetric structure as well as preparation method and application of alkaline electrolytic water hydrogen production diaphragm

Abstract

The invention discloses an alkaline electrolytic water hydrogen production diaphragm with an asymmetric structure as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) coating a supporting plate with a first layer of membrane casting solution, then placing a separation net, then coating the separation net with a second layer of membrane casting solution, and carrying out unreeling and compounding to form a diaphragm precursor; and (2) carrying out phase separation on the second layer of membrane casting solution coated on the upper surface of the separation net by adopting a steam induced phase separation method, then immersing the diaphragm precursor into a gel bath for solidification and shaping, and finally cleaning and rolling to obtain the diaphragm. The diaphragm prepared by the invention has an asymmetric structure, and dense holes are formed in one side, so that the gas resistance can be improved; the other side of the diaphragm is of a relatively open macroporous structure, so that the mass transfer resistance of OH <-> can be reduced, the resistance of the diaphragm is favorably reduced, and the electrolysis energy consumption is reduced; and the membrane is prepared by adopting a two-step coating method, so that the efficiency can be improved while the bubble defect of the membrane is reduced, and the membrane has a relatively good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen energy, and in particular, relates to a hydrogen production diaphragm with an asymmetric structure for alkaline water electrolysis and a preparation method and application thereof. BACKGROUND

[0002] Hydrogen energy, as a secondary energy source with abundant resources, green and low carbon, and wide application, is gradually becoming one of the important carriers of global energy transformation development. Hydrogen energy is difficult to obtain directly in large quantities from nature and needs to be prepared by different technical paths and production processes. At present, the main hydrogen production paths include three kinds of hydrogen production from fossil energy reform, hydrogen production from industrial by-product gas and hydrogen production from water electrolysis. So far, hydrogen, as a raw material and intermediate product of chemical production, is mainly obtained by hydrogen production from fossil energy and by-product. Although the cost of hydrogen production from fossil energy is relatively low, due to the non-renewable nature of the raw material and the environmental pollution caused by the hydrogen production process. Compared with hydrogen production from fossil energy, hydrogen production from water electrolysis can obtain hydrogen by electrolyzing water with renewable power supply such as photovoltaic power generation, wind power, and hydropower. The use process can achieve zero carbon emission and green hydrogen production.

[0003] Alkaline water electrolysis hydrogen production technology is relatively mature, simple to operate, and high in hydrogen production purity. The principle of alkaline water electrolysis hydrogen production is relatively simple. The alkaline water electrolysis cell is the main equipment of the alkaline water electrolysis hydrogen production device, which is composed of multiple electrolytic cells. Each electrolytic cell includes an anode, a cathode, a diaphragm and an electrolyte. The anode produces oxygen, the cathode produces hydrogen, and the diaphragm has the following functions: (1) providing an ion channel to reduce the resistance of hydroxyl ion transfer; (2) fully absorbing alkali solution as a barrier to prevent the mixing of hydrogen and oxygen. Therefore, in order to ensure the purity of the gas produced by electrolysis and the safety of the electrolysis cell, the diaphragm is required to strictly separate hydrogen and oxygen (mixing of hydrogen and oxygen may cause explosion), which requires the diaphragm to have good air tightness, and its existence allows ions in the solution to freely migrate between the cathode and the anode, i.e. the diaphragm has good electrolyte permeability and as low resistance as possible. The quality of the diaphragm directly affects the gas purity and energy consumption.

[0004] The existing technical means is usually to prepare the composite separator by the method of coating both sides at the same time, such as described in CN11869538A, taking polyphenylene sulfide (PPS) as a supporting mesh, taking a mixture of polysulfone and zirconium dioxide as slurry, adopting slot-die quantitative coating technology, coating slurry on the mesh on both sides at the same time, and then adopting vapor-induced phase separation (VIPS) to perform phase separation, to prepare a separator with a large pore structure, and by adjusting the different VIPS conditions on both sides, an asymmetric separator with different opening structures is prepared. The asymmetric structure separator is successfully prepared by this method, which has lower electrolysis voltage, higher gas purity and faster stability. However, this method has the following disadvantages: (1) the air inside the mesh cannot be well removed during the coating process, which is easy to cause bubble defects; (2) the phase separation on both sides is controlled by VIPS, but it is still difficult to improve the opening rate and pore size of the large pore side; (3) in the VIPS process, high-temperature and high-humidity steam is used as a non-solvent for induced phase separation, which requires high precision in equipment control, and once temperature difference occurs, steam condensation will occur, resulting in defects; and the two sides must have excellent isolation, otherwise the steam will penetrate, affecting the film structure on both sides. For example, in the prior arts CN116238174A, CN114561654A and WO2009147084A1, the preparation technologies described therein are similar in principle, both of which adopt double-sided coating of slurry, and subsequent gel bath setting to form pores, and the prepared separator has a symmetrical structure on both sides, especially the surface pore size, which has little difference on both sides, which greatly increases the mass transfer resistance of OH - , and increases the electrolysis energy consumption. At the same time, due to the large viscosity of the slurry and the porous structure of the polyphenylene sulfide (PPS) mesh used for reinforcement with a thickness of 100-300 μm, the air inside the mesh is not easy to remove, resulting in more bubble defects in the separator, reducing the gas blocking effect of the separator, and reducing the gas purity and safety.

[0005] Therefore, the present application is proposed. SUMMARY

[0006] The present application aims to at least solve one of the problems in the related art. To this end, the embodiments of the present application provide an asymmetric structure alkaline electrolytic water hydrogen production separator and a preparation method and application thereof.

[0007] In a first aspect, the embodiments of the present application provide a method for preparing an asymmetric structure alkaline electrolytic water hydrogen production separator, comprising the following steps:

[0008] (1) coating a first layer of casting fluid on a supporting plate, then placing a mesh, and then coating a second layer of casting fluid on the mesh, and after winding, a separator precursor is formed;

[0009] (2) using a steam-induced phase separation method to separate the second layer of casting solution coated on the upper surface of the spacer net, and then immersing the membrane precursor into a gel bath for gelation, and finally cleaning and rolling to obtain the asymmetric structure alkaline electrolysis water hydrogen production membrane.

[0010] In the preparation of the alkaline electrolysis water hydrogen production membrane, the embodiment of the present application sets a support plate on one side of the spacer net to reduce the phase separation speed of the casting solution on one side of the spacer net, thereby forming an open macroporous structure on one side of the spacer net and a relatively dense pore structure on the other side, so that the membrane has an asymmetric porous structure, which can reduce the resistance of the membrane; the continuous double coating method used in the embodiment of the present application can reduce the defects caused by the entrapment of bubbles; at the same time, the embodiment of the present application uses steam-induced phase separation of the casting solution on one side of the spacer net, which is a simpler process that can reduce the requirement for equipment control accuracy and improve the product yield.

[0011] In some embodiments, the support plate is a support plate with a groove, and the thickness of the support plate is 1mm-2mm.

[0012] Preferably, the material of the support plate is polyethylene terephthalate, polyethylene or polypropylene.

[0013] In some embodiments, the material of the spacer net is polyphenylene sulfide.

[0014] In some embodiments, the chemical composition of the first layer of casting solution and the second layer of casting solution is the same, and both are composed of 8wt%-16wt% organic heat-resistant polymer, 30wt%-50wt% inorganic nano material, 0.1wt%-4wt% pore-forming agent and 38wt%-50wt% organic solvent.

[0015] Preferably, the organic heat-resistant polymer includes at least one of polysulfone, polyether sulfone and polyphenyl sulfone.

[0016] Preferably, the inorganic nano material is nano zirconium oxide, the particle size of which is 10nm-100nm, and the bulk density is 0.3g / mL-1g / mL.

[0017] Preferably, the pore-forming agent includes at least one of glycerol, polyethylene glycol, polyvinylpyrrolidone, Tween and lithium chloride.

[0018] Preferably, the organic solvent includes at least one of N-methyl pyrrolidone, dimethylformamide, dimethylacetamide and N-ethyl pyrrolidone.

[0019] In some embodiments, the thickness of the first layer of casting solution and the second layer of casting solution is 50μm-500μm.

[0020] And / or, the coating is applied using a slot coating method.

[0021] In some embodiments, when phase separation is performed using the steam-induced phase separation method, the zone temperature is 25°C to 80°C, the relative humidity is 30% to 90%, and the residence time is 30s to 1min.

[0022] In some embodiments, the gel bath is pure water or a mixture of water and N-methylpyrrolidone, and the temperature of the gel bath is 25°C to 70°C.

[0023] And / or, the solidification and conditioning time is 3 min to 15 min.

[0024] In some embodiments, the cleaning is performed using water at 80°C to 100°C.

[0025] Secondly, embodiments of the present invention also propose an asymmetric alkaline water electrolysis hydrogen production membrane, wherein the membrane is prepared by the method described in the first aspect.

[0026] The diaphragm in this embodiment of the invention has an asymmetrical structure, with one side being a dense pore structure to enhance gas barrier properties, and the other side being a relatively open macroporous structure to reduce OH groups. - The reduced mass transfer resistance helps to lower the resistance of the diaphragm and reduce electrolysis energy consumption.

[0027] Thirdly, embodiments of the present invention also propose the application of the asymmetric structure alkaline water electrolysis hydrogen production diaphragm as described in the second aspect in an alkaline electrolyzer. Attached Figure Description

[0028] Figure 1 The image shows an SEM image of the asymmetric alkaline water electrolysis hydrogen production membrane prepared in Example 1 of this invention, where (a) shows the pore structure of the dense surface and (b) shows the pore structure of the macropore surface.

[0029] Figure 2 This is a SEM image of the asymmetric alkaline water electrolysis hydrogen production membrane prepared in Example 1 of the present invention.

[0030] Figure 3 This is a SEM image of the symmetrical alkaline water electrolysis hydrogen production membrane prepared in Comparative Example 1. Detailed Implementation

[0031] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0032] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0033] In this article, the words “contain” and “include” and their various variations mean that other elements or wholes may be included but not specifically described.

[0034] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone.

[0035] In a first aspect, embodiments of the present invention provide a method for preparing an asymmetric structure alkaline water electrolysis membrane for hydrogen production, comprising the following steps:

[0036] (1) First, a first layer of casting liquid is coated on the support plate, then a separator is placed, and then a second layer of casting liquid is coated on the separator. After unwinding, the separator precursor is formed.

[0037] (2) The second layer of casting liquid coated on the surface of the separator is separated by steam-induced phase separation method. Then the separator precursor is immersed in a gel bath for solidification and molding. Finally, after cleaning and winding, the asymmetric structure alkaline water electrolysis hydrogen production separator is obtained.

[0038] In some embodiments, the support plate is a support plate with grooves, and the thickness of the support plate is 1mm to 2mm, such as 1mm, 1.5mm, 1.8mm, 2mm, etc., which are not limiting examples; and it should be noted that the depth of the grooves is not particularly limited, and those skilled in the art can select it according to the actual needs of diaphragms of different thicknesses.

[0039] And / or, the support plate is made of polyethylene terephthalate (PET), polyethylene (PE), or polypropylene (PP), preferably polyethylene terephthalate (PET). Polyethylene terephthalate (PET) as a support plate is not only compatible with the casting solution, but also has hydrophilic properties, which allows for slow microphase separation of the casting solution through capillary permeation between the casting solution and the support plate, achieving a delayed phase separation effect and thus forming a double continuous macroporous structure.

[0040] In some embodiments, the mesh is made of polyphenylene sulfide (PPS).

[0041] In some embodiments, the first layer casting solution and the second layer casting solution have the same chemical composition, both being composed of 8 wt% to 16 wt% organic heat-resistant polymer (non-limiting examples, such as 8 wt%, 10 wt%, 12 wt%, 16 wt%, etc.), 30 wt% to 50 wt% inorganic nanomaterials (non-limiting examples, such as 30 wt%, 35 wt%, 40 wt%, 50 wt%, etc.), 0.1 wt% to 4 wt% pore-forming agent (non-limiting examples, such as 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, etc.), and 38 wt% to 50 wt% organic solvent (non-limiting examples, such as 38 wt%, 40 wt%, 45 wt%, 50 wt%, etc.).

[0042] Preferably, the organic heat-resistant polymer includes at least one of polysulfone, polyethersulfone, and polyphenylsulfone;

[0043] Preferably, the inorganic nanomaterial is nano-zirconia with a particle size of 10nm to 100nm (non-limiting examples include 10nm, 20nm, 50nm, 80nm, 100nm, etc.) and a bulk density of 0.3g / mL to 1g / mL (non-limiting examples include 0.3g / mL, 0.5g / mL, 0.8g / mL, 1g / mL, etc.).

[0044] Preferably, the pore-forming agent includes at least one of glycerol, polyethylene glycol, polyvinylpyrrolidone, Tween, and lithium chloride;

[0045] Preferably, the organic solvent includes at least one of N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and N-ethylpyrrolidone.

[0046] In some embodiments, the thickness of the first casting solution and the second casting solution is 50 μm to 500 μm, and non-limiting examples include: 50 μm, 100 μm, 200 μm, 450 μm, 500 μm, etc.

[0047] And / or, the coating is applied using a slot coating method.

[0048] The embodiments of the present invention can effectively remove the air carried by the separator by applying continuous double coating to both sides of the separator, thereby reducing defects caused by air bubbles.

[0049] In some embodiments, when the vapor-induced phase separation method is used for phase separation, the zone temperature is 25°C to 80°C (non-limiting examples include 25°C, 30°C, 50°C, 65°C, 80°C, etc.), the relative humidity is 30% to 90% (non-limiting examples include 30% to 45% to 50% to 60% to 85% to 90%), and the residence time is 30s to 1min (non-limiting examples include 30s to 1min).

[0050] This invention embodiment achieves a relatively dense pore structure on one side of the mesh by performing steam-induced phase separation. Furthermore, the conditions for unilateral steam-induced phase separation are easier to control, thereby reducing the precision requirements for equipment control and improving product yield.

[0051] In some embodiments, the gel bath is pure water or a mixture of water and N-methylpyrrolidone, and the temperature of the gel bath is 25°C to 70°C.

[0052] And / or, the solidification and conditioning time is 3 min to 15 min, and non-limiting examples include: 3 min, 5 min, 8 min, 10 min, 12 min, 15 min, etc.

[0053] In some embodiments, the cleaning is performed using water at 80°C to 100°C to remove the support plate on the side of the first layer of casting liquid.

[0054] Secondly, embodiments of the present invention also propose an asymmetric alkaline water electrolysis hydrogen production membrane, wherein the membrane is prepared by the method described in the first aspect.

[0055] Thirdly, embodiments of the present invention also propose the application of the asymmetric structure alkaline water electrolysis hydrogen production diaphragm as described in the second aspect in an alkaline electrolyzer.

[0056] The following are non-limiting embodiments and comparative examples of the present invention. It should be noted that the schemes in the comparative examples are not prior art, but are only set up for comparison with the schemes in the embodiments, and are not intended to limit the present invention. Unless otherwise stated, all raw materials used in the embodiments and comparative examples are conventional commercially available products, or can be prepared by known methods.

[0057] Example 1

[0058] A method for preparing an asymmetric structure alkaline water electrolysis membrane for hydrogen production includes the following steps:

[0059] (1) A grooved polyethylene terephthalate (PET) sheet with a thickness of 2 mm was used as a support plate. A first layer of casting solution (100 μm thick) was first coated on the PET support plate by slit coating. Then, a polyphenylene sulfide (PPS) mesh was placed on the surface of the first layer of casting solution. Subsequently, a second layer of casting solution (100 μm thick) was coated on the PPS mesh. After unwinding, the membrane precursor was formed. The first and second layers of casting solution were prepared by ball milling and dispersing 10 wt% polysulfone, 40 wt% nano zirconium oxide (particle size of 50 nm, bulk density of 0.5 g / mL), 1 wt% polyvinylpyrrolidone and 49 wt% N-methylpyrrolidone, and then dissolving and degassing at 100 °C.

[0060] (2) The second layer of casting liquid coated on the surface of the separator is separated by vapor-induced phase separation (VIPS). The temperature of the controlled area is 25℃ and the relative humidity is 85%. After phase separation for 30s, the separator precursor is immersed in a pure water bath at 60℃ for solidification and fixation for 10min. Finally, it is washed with hot water at 80℃ for 30min to remove the PET support plate. After winding, the asymmetric structure alkaline water electrolysis hydrogen production separator can be obtained.

[0061] Figure 1 The images show SEM images of the asymmetric alkaline water electrolysis hydrogen production membrane prepared in Example 1, where (a) shows the pore structure of the dense surface and (b) shows the pore structure of the macroporous surface. As can be seen from the images, the asymmetric alkaline water electrolysis hydrogen production membrane prepared in Example 1 has a dense pore structure on one side, which can improve gas barrier properties; and a relatively open macroporous structure on the other side, which can reduce OH- ions. - The mass transfer resistance is reduced, which helps to lower the resistance of the diaphragm.

[0062] Example 2

[0063] A method for preparing an asymmetric structure alkaline water electrolysis membrane for hydrogen production includes the following steps:

[0064] (1) A grooved polyethylene terephthalate (PET) sheet with a thickness of 2 mm was used as a support plate. A first layer of casting solution (100 μm thick) was first coated on the PET support plate by slit coating. Then, a polyphenylene sulfide (PPS) mesh was placed on the surface of the first layer of casting solution. Subsequently, a second layer of casting solution (100 μm thick) was coated on the PPS mesh. After unwinding, the membrane precursor was formed. The first and second layers of casting solution were prepared by ball milling and dispersing 10 wt% polysulfone, 40 wt% nano zirconium oxide (particle size of 50 nm, bulk density of 0.5 g / mL), 1 wt% polyvinylpyrrolidone and 49 wt% N-methylpyrrolidone, and then dissolving and degassing at 100 °C.

[0065] (2) The second layer of casting liquid coated on the surface of the separator is separated by vapor-induced phase separation (VIPS). The temperature of the controlled area is 25℃ and the relative humidity is 40%. After phase separation for 30s, the separator precursor is immersed in a 25℃ pure water bath for solidification and fixation for 5min. Finally, it is washed with 80℃ hot water for 30min to remove the PET support plate. After winding, the asymmetric structure alkaline water electrolysis hydrogen production separator can be obtained.

[0066] Example 3

[0067] A method for preparing an asymmetric structure alkaline water electrolysis membrane for hydrogen production includes the following steps:

[0068] (1) A grooved polyethylene terephthalate (PET) sheet with a thickness of 2 mm was used as a support plate. A first layer of casting solution (100 μm thick) was first coated on the PET support plate by slit coating. Then, a polyphenylene sulfide (PPS) mesh was placed on the surface of the first layer of casting solution. Subsequently, a second layer of casting solution (100 μm thick) was coated on the PPS mesh. After unwinding, the membrane precursor was formed. The first and second layers of casting solution were prepared by ball milling and dispersing 10 wt% polysulfone, 40 wt% nano-zirconia (particle size of 20 nm, bulk density of 0.35 g / mL), 1 wt% polyethylene glycol and 49 wt% N-methylpyrrolidone, and then dissolving and degassing at 100 °C.

[0069] (2) The second layer of casting solution coated on the surface of the separator is separated by vapor-induced phase separation (VIPS). The temperature of the controlled area is 25℃ and the relative humidity is 85%. After phase separation for 30s, the separator precursor is immersed in a mixture of water and N-methylpyrrolidone (wherein the N-methylpyrrolidone solution accounts for 50wt%) for solidification and fixation for 15min. Finally, it is washed with hot water at 80℃ for 30min to remove the PET support plate. After winding, the asymmetric structure alkaline water electrolysis hydrogen production separator can be obtained.

[0070] Comparative Example 1

[0071] A method for preparing a symmetrical alkaline water electrolysis membrane for hydrogen production includes the following steps:

[0072] (1) A polyphenylene sulfide (PPS) separator is used, and casting solution is coated on both sides of the separator simultaneously. After unwinding, the separator precursor is formed by composite coating. The casting solution is prepared by ball milling and dispersing 10wt% polysulfone, 40wt% nano-zirconia (particle size of 50nm, bulk density of 0.6g / mL), 1wt% polyvinylpyrrolidone and 49wt% N-methylpyrrolidone, and then dissolving and degassing at 100℃.

[0073] (2) The casting liquid on both sides of the membrane precursor mesh was separated by the vapor-induced phase separation method (VIPS). The temperature of the controlled area was 25°C and the relative humidity was 85%. After the phase separation was induced for 30 seconds, the membrane precursor was then immersed in a pure water bath at 60°C for solidification and fixation for 5 minutes. Finally, it was wound up to obtain a symmetrical alkaline water electrolysis hydrogen production membrane.

[0074] Comparative Example 2

[0075] A method for preparing a symmetrical alkaline water electrolysis membrane for hydrogen production includes the following steps:

[0076] (1) A polyphenylene sulfide (PPS) separator is used, and casting solution is coated on both sides of the separator simultaneously. After unwinding, the separator precursor is formed by composite coating. The casting solution is prepared by ball milling and dispersing 10wt% polysulfone, 40wt% nano-zirconia (particle size of 20nm, bulk density of 0.35g / mL), 1wt% polyethylene glycol and 49wt% N-methylpyrrolidone, and then dissolving and degassing at 100℃.

[0077] (2) The casting liquid on both sides of the membrane precursor mesh was separated by vapor-induced phase separation (VIPS). The temperature of the controlled area was 25°C and the relative humidity was 85%. After phase separation for 30 seconds, the membrane precursor was then immersed in a mixture of water and N-methylpyrrolidone (wherein the N-methylpyrrolidone solution accounted for 50 wt%) for solidification and fixation for 15 minutes. Finally, it was wound up to obtain a symmetrical alkaline water electrolysis hydrogen production membrane.

[0078] like Figure 2 and Figure 3 The images shown are SEM images of the asymmetric alkaline water electrolysis hydrogen production membrane prepared in Example 1 and the symmetric alkaline water electrolysis hydrogen production membrane prepared in Comparative Example 1, respectively. It can be seen from the images that, due to the simultaneous coating method used in Comparative Example 1, the membrane prepared in Comparative Example 1 (…) Figure 3 Because of bubble entrainment, the cross-section of the membrane has bubble defects; in contrast, Embodiment 1 of the present invention uses a continuous two-coating method, which can reduce the defects caused by bubble entrainment, so that the prepared diaphragm is free of bubble defects. Figure 2 ).

[0079] The performance of the asymmetric alkaline water electrolysis hydrogen production membranes prepared in Examples 1-3 and the symmetric alkaline water electrolysis hydrogen production membrane prepared in Comparative Example 1 were tested, and the results are shown in Table 1.

[0080] Table 1

[0081]

[0082]

[0083] As shown in Table 1, compared with Comparative Examples 1 and 2, the asymmetric alkaline water electrolysis hydrogen production membrane prepared by the method of the present invention has superior performance. Thanks to its high porosity and open pore structure, it has lower resistance, and thus higher electrolysis efficiency and lower voltage.

[0084] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0085] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing an asymmetric structure alkaline water electrolysis membrane for hydrogen production, characterized in that, Includes the following steps: (1) First, a first layer of casting liquid is coated on the support plate, then a separator is placed, and then a second layer of casting liquid is coated on the separator. After unwinding, the separator precursor is formed. (2) The second layer of casting liquid coated on the surface of the separator is separated by steam-induced phase separation method. Then the separator precursor is immersed in a gel bath for solidification and molding. Finally, after cleaning and winding, the asymmetric structure alkaline water electrolysis hydrogen production separator is obtained.

2. The method for preparing an asymmetric alkaline water electrolysis hydrogen production membrane according to claim 1, characterized in that, The support plate is a support plate with grooves, and the thickness of the support plate is 1mm to 2mm; And / or, the support plate is made of polyethylene terephthalate, polyethylene or polypropylene.

3. The method for preparing an asymmetric structure alkaline water electrolysis hydrogen production membrane according to claim 1, characterized in that, The mesh is made of polyphenylene sulfide.

4. The method for preparing an asymmetric structure alkaline water electrolysis hydrogen production membrane according to claim 1, characterized in that, The first and second casting solutions have the same chemical composition, both being composed of 8wt% to 16wt% organic heat-resistant polymer, 30wt% to 50wt% inorganic nanomaterials, 0.1wt% to 4wt% pore-forming agent, and 38wt% to 50wt% organic solvent. Preferably, the organic heat-resistant polymer includes at least one of polysulfone, polyethersulfone, and polyphenylsulfone; Preferably, the inorganic nanomaterial is nano-zirconia with a particle size of 10 nm to 100 nm and a bulk density of 0.3 g / mL to 1 g / mL; Preferably, the pore-forming agent includes at least one of glycerol, polyethylene glycol, polyvinylpyrrolidone, Tween, and lithium chloride; Preferably, the organic solvent includes at least one of N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and N-ethylpyrrolidone.

5. The method for preparing an asymmetric alkaline water electrolysis hydrogen production membrane according to claim 1, characterized in that, The thickness of both the first and second casting solutions is 50 μm to 500 μm. And / or, the coating is applied using a slot coating method.

6. The method for preparing an asymmetric structure alkaline water electrolysis hydrogen production membrane according to claim 1, characterized in that, When using the steam-induced phase separation method for phase separation, the zone temperature is 25℃~80℃, the relative humidity is 30%~90%, and the residence time is 30s~1min.

7. The method for preparing an asymmetric structure alkaline water electrolysis membrane for hydrogen production according to claim 1, characterized in that, The gel bath is pure water or a mixture of water and N-methylpyrrolidone, and the temperature of the gel bath is 25℃~70℃. And / or, the solidification and conditioning time is 3 min to 15 min.

8. The method for preparing an asymmetric structure alkaline water electrolysis hydrogen production membrane according to claim 1, characterized in that, The cleaning process involves using water at 80℃ to 100℃.

9. An asymmetric structure alkaline water electrolysis membrane for hydrogen production, characterized in that, The diaphragm is prepared by the method according to any one of claims 1-8.

10. The application of the asymmetric structure alkaline water electrolysis hydrogen production diaphragm as described in claim 9 in an alkaline electrolyzer.

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