A method for preparing a non-biphasic hydroxide-based alkaline electrolytic water membrane

Abstract

The application relates to the technical field of diaphragm preparation, in particular to a preparation method of an alkaline electrolytic water diaphragm based on non-zwitterionic hydroxide. The application selects Fe(OH)3, Ni(OH)2, Mg(OH)2 and Al(OH)3 as inorganic fillers to prepare a composite alkaline electrolytic water diaphragm, and the mass ratio of the inorganic fillers, PSF and PVP is 4:3:2. Compared with the traditional technology, the content of the organic filler in the diaphragm is reduced, the chemical stability of the diaphragm is improved, the diaphragm has the advantages of simple operation, low cost, large output and the like, and the diaphragm has the characteristics of low surface resistance and high air tightness.

Description

Technical Field

[0001] This invention relates to the field of membrane preparation technology, and specifically to a method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide. Background Technology

[0002] Alkaline water electrolysis (AWE) technology, as the most mature (TRL 9) method for hydrogen production through water electrolysis, directly impacts the energy consumption, current density, and stability of the electrolyzer due to the performance of its membrane. To replace early asbestos membranes and overcome the problems of poor structural stability, high sheet resistivity, and low current density of traditional membranes, researchers have developed various organic-inorganic composite membranes. Technological advancements focus on both material composition and structural design, aiming to synergistically improve gas barrier properties, ionic conductivity, and mechanical strength.

[0003] Currently, mainstream technical approaches include multilayer composite structure design. For example, the Tsinghua University patent (CN115029732B) reports the use of polyetheretherketone (PES) and polyarylethersulfone (PPES) as matrices, adding hydrophilic inorganic nanoparticles such as zirconium oxide (ZrO2) and titanium oxide (TiO2), and forming the structure using a phase transformation process. This structure possesses a nanoscale dense skin layer to achieve gas barrier properties, and a finger-like porous layer containing a supporting mesh to promote ion transport and provide mechanical support. Another approach focuses on optimizing commercial membranes such as the Zirfon series, improving performance through process control. For example, pre-evaporation heat treatment (~50 °C) can be used to reduce surface porosity and roughness, improving density; or a "gap strategy" using inorganic particles of different sizes (such as ZrO2 / TiO2 composites) can be employed to achieve a narrower pore size distribution and lower resistivity.

[0004] Nevertheless, existing technologies still face the following common challenges: most rely on hydrophilic additives such as polyvinylpyrrolidone (PVP) to improve wettability, but this compromises mechanical and chemical stability; the preparation process is complex, making it difficult to balance performance and cost; in addition, the durability of the diaphragm under long-term operation in strong alkaline, high-temperature and high-bubble scouring environments still needs to be improved.

[0005] Specifically, although significant progress has been made in existing alkaline water electrolysis membrane technology, there are still several key technical shortcomings, which directly affect the performance, durability, and economy of the electrolyzer.

[0006] 1) Insufficient ionic conductivity of inorganic fillers restricts energy efficiency improvement. While widely used inorganic fillers (such as metal oxides like ZrO2, TiO2, and Al2O3) possess good chemical stability and mechanical strength, their ion conduction mechanisms are primarily based on physical adsorption and surface hydroxyl groups, resulting in limited intrinsic hydroxide ion (OH⁻) conductivity. For example, the introduction of ZrO2 into Zirfon series membranes mainly contributes to hydrophilicity and pore size control, but has a weak direct impact on ionic conductivity, making it difficult to further reduce membrane surface resistivity and thus limiting current density and high-efficiency operation. In contrast, hydroxide materials (such as layered bimetallic hydroxides, LDH) have superior ion exchange capacity and hydroxyl migration channels, with intrinsic ionic conductivity significantly higher than oxides, but they have not yet been systematically developed and utilized in existing technologies.

[0007] 2) Hydrophilic additives sacrifice long-term stability To compensate for the insufficient hydrophilicity of oxide fillers, existing membranes generally rely on polymer additives such as polyvinylpyrrolidone (PVP). These substances are prone to dissolution, hydrolysis, or degradation under strong alkaline and high-temperature environments, leading to a gradual decrease in membrane wettability, microstructural aging, and consequently, increased electrical resistance and exacerbated gas cross-linking. Multiple studies have indicated that PVP degradation is one of the main causes of performance degradation in Zirfon membranes. If intrinsically hydrophilic and stable hydroxide materials could be used, the use of organic additives could be reduced or even avoided, thereby improving the chemical stability and lifespan of the membrane.

[0008] 3) Highly uniform microstructures are difficult to fabricate Existing composite membranes mostly rely on phase inversion processes, and their film formation is significantly affected by the solvent system, coagulation conditions, and the dispersion stability of inorganic particles, making them prone to local agglomeration, finger-like pore collapse, or skin defects (such as the structural inhomogeneity problem mentioned in CN115029732B). Especially when using oxides with high density and wide particle size distribution, it is even more difficult to achieve nanoscale uniform dispersion of fillers in the polymer matrix, leading to increased local resistance or decreased gas barrier properties in the membrane. Hydroxide materials, through the control of crystal morphology and surface functionalization, can achieve more uniform composite and film formation, and are expected to yield low-resistance membranes with more consistent pore structures.

[0009] 4) Durability under high temperature and strong alkaline environments remains a challenge. Existing oxide-polymer composite membranes still face problems such as decreased interfacial compatibility, polymer degradation, and inorganic particle corrosion during long-term operation. Especially in 30% KOH solutions above 80 °C, traditional polysulfone and polyethersulfone matrix materials undergo hydrolysis and chain rearrangement, leading to a gradual decline in membrane performance. Hydroxide materials typically possess better alkali stability and lower solubility products; if used as the main functional filler, they can enhance the overall environmental tolerance of the membrane.

[0010] In summary, existing alkaline water electrolysis membrane technology still faces systemic problems in terms of material selection (relying on oxides rather than hydroxides), structural stability, process simplicity, and environmental durability. This provides a clear direction for technological improvement and application value for developing a new generation of membranes using non-amphoteric hydroxides as the core functional filler. Summary of the Invention

[0011] In view of this, in order to solve this problem, the purpose of this invention is to provide a method for preparing an alkaline water electrolysis membrane based on non-ampholy hydroxides, which uses four non-ampholy hydroxides that can remain stable in a strongly alkaline environment as inorganic fillers to prepare a composite alkaline water electrolysis membrane.

[0012] This invention uses Fe(OH)3, Ni(OH)2, Mg(OH)2, and Al(OH)3 as inorganic fillers to prepare a composite alkaline water electrolysis membrane. The mass ratio of inorganic filler, PSF, and PVP is 4:3:2. Compared with traditional technologies, this reduces the content of organic filler in the membrane, which is beneficial to improving the chemical stability of the membrane. This invention has advantages such as simple operation, low cost, and high yield, and the membrane has the characteristics of low surface resistivity and high airtightness.

[0013] It is worth noting that most of the inorganic fillers currently used are oxides (such as ZrO2, TiO2, Al2O3, etc.), while hydroxides (such as Ni(OH)2, Mg(OH)2, etc.) have better anion conductivity—because their layered structure and hydroxyl-rich properties are conducive to OH⁻ migration, and they have significant potential in improving ionic conductivity.

[0014] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide includes the following steps: a. Preparation of inorganic fillers: The method for preparing Fe(OH)3 powder is as follows: 15.2 g of FeCl3 powder is slowly added to 45 ml of ammonia water with a mass fraction of 12%. After sealing the beaker with plastic wrap, it is sonicated for 30 s, and a red flocculent precipitate appears in the beaker. The solution is allowed to stand for 1 h, and after the flocculent precipitate has aged, the precipitate is collected and washed three times with water and ethanol alternately. The product is then dried in a vacuum drying oven at 30 ℃ for 12 h to obtain brick red Fe(OH)3 powder. The other inorganic fillers were prepared using the same method. The amounts of NiCl2, MgCl2, and AlCl3 were 16.34 g, 14.0 g, and 17.09 g, respectively, corresponding to 50 ml, 35 ml, and 55 ml of ammonia water with a mass fraction of 12%.

[0015] b. Preparation of casting solution: The Fe(OH)3 casting solution was prepared as follows: 27.5 g of N-methylpyrrolidone (NMP) was added to a 100 ml three-necked flask, and 7.5 g of polysulfone (PSF) was added at a stirring rate of 100 r / min. The stirring speed was adjusted to 300 r / min at room temperature and stirred for 12 h until the polysulfone was completely dissolved. The stirring speed was reduced to 100 r / min, and 5 g of polyvinylpyrrolidone and 125 mg of polyvinyl alcohol (PVA) were added respectively. The stirring speed was adjusted to 100 r / min at room temperature and stirred for 24 h until the particles were completely dissolved. The stirring speed was reduced to 100 r / min, and 10 g of Fe(OH)3 powder was added. The stirring speed was adjusted to 300 r / min and stirred for 24 h to obtain a red slurry fluid.

[0016] The method for preparing Ni(OH)2 casting solution is as follows: 39.4 g of N-methylpyrrolidone (NMP) is added to a 100 ml three-necked flask, and 7.5 g of polysulfone (PSF) is added at a stirring rate of 100 r / min. The stirring speed is adjusted to 300 r / min at room temperature and stirred for 12 h until the polysulfone is completely dissolved. The stirring speed is reduced to 100 r / min, and 5 g of polyvinylpyrrolidone and 125 mg of polyvinyl alcohol (PVA) are added respectively. The stirring speed is adjusted to 100 r / min at room temperature and stirred for 24 h until the particles are completely dissolved. The stirring speed is reduced to 100 r / min, 10 g of Ni(OH)2 powder is added, and the stirring speed is adjusted to 300 r / min. The mixture is stirred for 24 h to obtain a green slurry fluid.

[0017] The preparation method of Mg(OH)2 casting solution is as follows: 40.28 g of N-methylpyrrolidone (NMP) is added to a 100 ml three-necked flask, and 7.5 g of polysulfone (PSF) is added at a stirring rate of 100 r / min. The stirring speed is adjusted to 300 r / min at room temperature and stirred for 12 h until the polysulfone is completely dissolved. The stirring speed is reduced to 100 r / min, and 5 g of polyvinylpyrrolidone and 125 mg of polyvinyl alcohol (PVA) are added respectively. The stirring speed is adjusted to 100 r / min at room temperature and stirred for 24 h until the particles are completely dissolved. The stirring speed is reduced to 100 r / min, 10 g of Mg(OH)2 powder is added, and the stirring speed is adjusted to 300 r / min. The mixture is stirred for 24 h to obtain a white slurry fluid.

[0018] The Al(OH)3 casting solution was prepared as follows: 27.5 g of N-methylpyrrolidone (NMP) was added to a 100 ml three-necked flask, and 7.5 g of polysulfone (PSF) was added at a stirring rate of 100 r / min. The stirring speed was adjusted to 300 r / min at room temperature and stirred for 12 h until the polysulfone was completely dissolved. The stirring speed was reduced to 100 r / min, and 5 g of polyvinylpyrrolidone and 125 mg of polyvinyl alcohol (PVA) were added respectively. The stirring speed was adjusted to 100 r / min at room temperature and stirred for 24 h until the particles were completely dissolved. The stirring speed was reduced to 100 r / min, and 10 g of Al(OH)3 powder was added. The stirring speed was adjusted to 300 r / min and stirred for 24 h to obtain a white slurry fluid.

[0019] c. Degassing of casting solution: Seal the middle neck of the three-necked flask with filter paper and rubber bands, and place it in a vacuum drying oven at room temperature for 24 hours to completely eliminate air bubbles.

[0020] The degassing methods for different types of casting solutions are exactly the same.

[0021] d. Film scraping and phase transformation: Cut a PPS mesh and clamp it onto a glass plate, leaving a 2 cm gap between the left and right edges of the PPS mesh and the edge of the glass plate, and a 1.5 cm gap between the bottom edge of the PPS mesh and the edge of the glass plate. Evenly coat the degassed precursor slurry onto the top of the PPS mesh, and scrape it at a uniform speed from top to bottom with a scraper to form a 400 μm slurry film. Immediately immerse the glass plate with the slurry film into deionized water at room temperature and let it stand for 10-30 minutes until a stable, non-powdering wet composite membrane is formed.

[0022] The methods for scraping and phase inversion are exactly the same for different types of casting solutions.

[0023] e. Post-processing: The formed wet membrane is removed from the deionized water and rinsed with deionized water to thoroughly remove residual solvent and possible impurities. The cleaned wet membrane is placed on clean filter paper or absorbent cloth to absorb excess surface moisture, and finally the alkaline electrolytic water membrane based on non-amphoteric hydroxide is obtained.

[0024] The post-treatment methods for different types of casting solutions are exactly the same.

[0025] Compared with the prior art, the beneficial effects of the present invention are: This invention prepares a composite alkaline water electrolysis membrane by selecting Fe(OH)3, Ni(OH)2, Mg(OH)2, and Al(OH)3 as inorganic fillers, with a mass ratio of inorganic fillers, PSF, and PVP of 4:3:2. Compared with traditional technologies, this invention reduces the content of organic fillers in the membrane, which is beneficial to improving the chemical stability of the membrane. It has advantages such as simple operation, low cost, and high yield, and the membrane has the characteristics of low surface resistivity and high airtightness. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] Figure 1 This is a scanning electron microscope image of the surface of the Fe(OH)3 / PSF composite microporous membrane.

[0028] Figure 2 This is a cross-sectional scanning electron microscope image of the Fe(OH)3 / PSF composite microporous membrane.

[0029] Figure 3 This is a contact angle test diagram of the Fe(OH)3 / PSF composite microporous membrane surface.

[0030] Figure 4 The impedance diagrams are those of the Fe(OH)3 / PSF composite microporous membrane in Example 1 and the control impedance diagrams of the blank group.

[0031] Figure 5 This is a scanning electron microscope image of the surface of the Ni(OH)2 / PSF composite microporous membrane.

[0032] Figure 6 This is a scanning electron microscope image of the cross-section of the Ni(OH)2 / PSF composite microporous membrane.

[0033] Figure 7 This is a contact angle test diagram of the Ni(OH)2 / PSF composite microporous membrane surface.

[0034] Figure 8 The impedance diagrams are those of the Ni(OH)2 / PSF composite microporous membrane in Example 2 and the control impedance diagrams of the blank group.

[0035] Figure 9 This is a surface scanning electron microscope image of the Mg(OH)2 / PSF composite microporous membrane.

[0036] Figure 10This is a scanning electron microscope image of the cross-section of the Mg(OH)2 / PSF composite microporous membrane.

[0037] Figure 11 This is a contact angle test diagram of the Mg(OH)2 / PSF composite microporous membrane surface.

[0038] Figure 12 The impedance diagrams are those of the Mg(OH)2 / PSF composite microporous membrane in Example 3 and the control impedance diagram of the blank group.

[0039] Figure 13 This is a surface scanning electron microscope image of the Al(OH)3 / PSF composite microporous membrane.

[0040] Figure 14 This is a scanning electron microscope image of the cross-section of the Al(OH)3 / PSF composite microporous membrane.

[0041] Figure 15 This is a contact angle test diagram of the Al(OH)3 / PSF composite microporous membrane surface.

[0042] Figure 16 The impedance diagrams are those of the Al(OH)3 / PSF composite microporous membrane in Example 4 and the control impedance diagrams of the blank group. Detailed Implementation

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in the embodiments of this application, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in this application is merely for describing particular implementations and is not intended to limit the scope of this disclosure.

[0045] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; other experimental methods and technical means not specifically mentioned herein refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0046] To better illustrate the content of this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail in order to highlight the main points of this application.

[0047] Without conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of this application.

[0048] This invention discloses a method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide.

[0049] To better understand the present invention, the following embodiments are provided for further detailed description of the present invention, but they should not be construed as limiting the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are also considered to fall within the protection scope of the present invention.

[0050] Example 1 A method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide (Fe(OH)3) includes the following steps: a. Preparation of inorganic fillers: 15.2 g of FeCl3 powder was slowly added to 45 ml of 12% ammonia water. The beaker was then sealed with plastic wrap and sonicated for 30 s. A red flocculent precipitate appeared in the beaker. The solution was allowed to stand for 1 h. After the flocculent precipitate had aged, the precipitate was collected and washed three times with water and ethanol alternately. The product was then dried in a vacuum drying oven at 30 °C for 12 h to obtain brick-red Fe(OH)3 powder. b. Preparation of casting solution: 27.5 g of N-methylpyrrolidone (NMP) was added to a 100 ml three-necked flask, followed by 7.5 g of polysulfone (PSF) at a stirring speed of 100 r / min. The mixture was stirred at 300 r / min for 12 h at room temperature until the polysulfone was completely dissolved. The stirring speed was then reduced to 100 r / min, and 5 g of polyvinylpyrrolidone and 125 mg of polyvinyl alcohol (PVA) were added. The mixture was stirred at 100 r / min for 24 h at room temperature until the particles were completely dissolved. Finally, the stirring speed was reduced to 100 r / min, and 10 g of Fe(OH)3 powder was added. The stirring speed was then increased to 300 r / min, and the mixture was stirred for 24 h to obtain a red slurry. c. Degassing of casting solution: Seal the middle neck of the three-necked flask with filter paper and rubber bands, and place it in a vacuum drying oven at room temperature for 24 hours to completely eliminate air bubbles. d. Film scraping and phase transformation: Cut a PPS mesh and clamp it onto a glass plate, leaving a 2 cm gap between the left and right edges of the PPS mesh and the edge of the glass plate, and a 1.5 cm gap between the bottom edge of the PPS mesh and the edge of the glass plate. Evenly coat the degassed precursor slurry onto the top of the PPS mesh, and scrape it at a uniform speed from top to bottom with a scraper to form a 400 μm slurry film. Immediately immerse the glass plate with the slurry film into deionized water at room temperature and let it stand for 10-30 minutes until a stable, non-powdering wet composite membrane is formed. e. Post-processing: The formed wet membrane is removed from the deionized water and rinsed with deionized water to thoroughly remove residual solvent and possible impurities. The cleaned wet membrane is placed on clean filter paper or absorbent cloth to absorb excess water, and finally the alkaline water electrolysis membrane based on non-amphoteric hydroxide (Fe(OH)3) is obtained.

[0051] Example 2 A method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide (Ni(OH)2) includes the following steps: The difference between Example 2 and Example 1 is that the preparation methods of the remaining inorganic fillers are the same, the amount of NiCl2 used is 16.34 g, and the amount of ammonia water with a mass fraction of 12% is 50 ml.

[0052] The method for preparing Ni(OH)2 casting solution is as follows: 39.4 g of N-methylpyrrolidone (NMP) is added to a 100 ml three-necked flask, and 7.5 g of polysulfone (PSF) is added at a stirring rate of 100 r / min. The stirring speed is adjusted to 300 r / min at room temperature and stirred for 12 h until the polysulfone is completely dissolved. The stirring speed is reduced to 100 r / min, and 5 g of polyvinylpyrrolidone and 125 mg of polyvinyl alcohol (PVA) are added respectively. The stirring speed is adjusted to 100 r / min at room temperature and stirred for 24 h until the particles are completely dissolved. The stirring speed is reduced to 100 r / min, 10 g of Ni(OH)2 powder is added, and the stirring speed is adjusted to 300 r / min. The mixture is stirred for 24 h to obtain a green slurry fluid.

[0053] Example 3 A method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide (Mg(OH)2) includes the following steps: The difference between Example 3 and Example 1 is that the preparation methods of the remaining inorganic fillers are the same, the amount of MgCl2 used is 14.0 g, and the amount of ammonia water with a mass fraction of 12% is 35 ml.

[0054] The preparation method of Mg(OH)2 casting solution is as follows: 40.28 g of N-methylpyrrolidone (NMP) is added to a 100 ml three-necked flask, and 7.5 g of polysulfone (PSF) is added at a stirring rate of 100 r / min. The stirring speed is adjusted to 300 r / min at room temperature and stirred for 12 h until the polysulfone is completely dissolved. The stirring speed is reduced to 100 r / min, and 5 g of polyvinylpyrrolidone and 125 mg of polyvinyl alcohol (PVA) are added respectively. The stirring speed is adjusted to 100 r / min at room temperature and stirred for 24 h until the particles are completely dissolved. The stirring speed is reduced to 100 r / min, 10 g of Mg(OH)2 powder is added, and the stirring speed is adjusted to 300 r / min. The mixture is stirred for 24 h to obtain a white slurry fluid.

[0055] Example 4 A method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide (Al(OH)3) includes the following steps: The difference between Example 4 and Example 1 is that the preparation methods of the remaining inorganic fillers are the same, the amount of AlCl3 used is 17.09 g, and the corresponding amount of 12% ammonia water used is 55 ml. The Al(OH)3 casting solution was prepared as follows: 27.5 g of N-methylpyrrolidone (NMP) was added to a 100 ml three-necked flask, and 7.5 g of polysulfone (PSF) was added at a stirring rate of 100 r / min. The stirring speed was adjusted to 300 r / min at room temperature and stirred for 12 h until the polysulfone was completely dissolved. The stirring speed was reduced to 100 r / min, and 5 g of polyvinylpyrrolidone and 125 mg of polyvinyl alcohol (PVA) were added respectively. The stirring speed was adjusted to 100 r / min at room temperature and stirred for 24 h until the particles were completely dissolved. The stirring speed was reduced to 100 r / min, and 10 g of Al(OH)3 powder was added. The stirring speed was adjusted to 300 r / min and stirred for 24 h to obtain a white slurry fluid.

[0056] To further demonstrate the beneficial effects of the present invention and to better understand it, the following experimental examples further illustrate the technical features disclosed in the present invention, but should not be construed as limiting the present invention. Other improvements made by those skilled in the art based on the above-described invention, without inventive effort, are also considered to fall within the protection scope of the present invention.

[0057] Determination of alkali absorption rate: Prepare a 30 wt% KOH solution and cut three sets of 1 cm × 1 cm composite diaphragm samples, designated as Sample 1, Sample 2, and Sample 3. After drying, weigh the samples to obtain sample mass m1. Immerse the samples in the 30 wt% KOH solution. After soaking the samples in the alkali solution for 12 h, remove the samples from the alkali solution with tweezers, suspend them for 30 s to allow residual alkali solution to drip off naturally, and weigh them on a balance to obtain mass m2. The alkali absorption rate A of the diaphragm is calculated using the following formula:

[0058] Where: A--diaphragm alkali absorption rate, %; m1-sample mass before alkali immersion, g; m2-sample mass after alkali immersion, g.

[0059] Table 1. Alkali absorption rate test data of Fe(OH)3 / PSF composite microporous membrane in Example 1

[0060] It should be noted that an alkali absorption rate greater than 300% indicates that the membrane possesses extremely high porosity or strong hydrophilicity. A high alkali absorption rate means that the pores inside the membrane are fully filled with electrolyte, forming continuous and abundant ion transport channels.

[0061] like Figure 1 SEM images of the Fe(OH)3 / PSF composite microporous membrane show that the membrane has abundant pores, which is beneficial for electrolyte adsorption.

[0062] like Figure 2 The cross-sectional SEM of the Fe(OH)3 / PSF composite microporous membrane shows that the membrane has abundant sponge-like pores, which is very conducive to the adsorption of alkaline solution, and further verifies the alkaline adsorption rate test.

[0063] like Figure 3 The contact angle of about 55° indicates that the Fe(OH)3 / PSF composite microporous membrane can be well wetted by KOH electrolyte, which is a necessary prerequisite for the electrolyte to penetrate the membrane and form ion conduction channels.

[0064] The sheet resistance test was performed using a KOSTER electrochemical workstation. Before conducting the diaphragm sheet resistance test, a 4cm² effective area without a diaphragm was first used. 2 The resistance of the fixture was measured twice in a 30 wt% KOH solution at 60 ℃, and recorded as blank group 1 and blank group 2. A 2 cm × 2 cm composite diaphragm was cut, installed in the fixture, and its resistance was measured twice in a 30 wt% KOH solution at 60 ℃. The average of the two measurements was taken, and the data is as follows. The method for testing the surface resistance of other diaphragms is the same.

[0065] Table 2. Sheet resistance test parameters and data of Fe(OH)3 / PSF composite microporous membrane in Example 1

[0066] The sheet resistivity of a traditional asbestos diaphragm is approximately 0.2 Ω cm. 2 The previous method, using diaphragms around 0.15-0.3 Ω cm, is now obsolete. The current mainstream method uses composite diaphragms (such as the Zirfon series), with sheet resistivity typically between 0.15 and 0.3 Ω cm. 2 The sheet resistance of the diaphragm described in this invention is significantly better than that of commercial diaphragms.

[0067] Table 3. Alkali absorption rate test data of Ni(OH)2 / PSF composite microporous membrane in Example 2

[0068] like Figure 6 SEM images of the Ni(OH)2 / PSF composite microporous membrane cross-section show that the membrane has abundant finger-like and sponge-like pores, which are highly conducive to the adsorption of alkaline solutions. This further verifies the alkaline adsorption rate test.

[0069] Table 4. Sheet resistance test parameters and data of Ni(OH)2 / PSF composite microporous membrane in Example 2

[0070] Table 5. Alkali absorption rate test data of Mg(OH)2 / PSF composite microporous membrane in Example 3

[0071] Table 6. Sheet resistance test parameters and data of Mg(OH)2 / PSF composite microporous membrane in Example 3

[0072] Table 7. Alkali absorption rate test data of Al(OH)3 / PSF composite microporous membrane in Example 4

[0073] Table 8. Sheet resistance test parameters and data of Al(OH)3 / PSF composite microporous membrane in Example 4

[0074] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide, characterized in that, Includes the following steps: a. Preparation of inorganic fillers: The method for preparing Fe(OH)3 powder is as follows: FeCl3 powder is slowly added to ammonia water with a mass fraction of 12%, ultrasonicated and allowed to stand, the precipitate is collected, and the powder is washed three times alternately with water and ethanol, and then dried to obtain brick red Fe(OH)3 powder. The preparation methods for the remaining inorganic fillers are the same, using NiCl2 powder, MgCl2 powder, and AlCl3 powder to prepare Ni(OH)2 powder, Mg(OH)2 powder, and Al(OH)3 powder, respectively; b. Preparation of casting solution: The Fe(OH)3 casting solution is prepared as follows: 25-35g of N-methylpyrrolidone (NMP) is added to a 100ml three-necked flask. 6-10g of polysulfone (PSF) is added while stirring at 50-100r / min. The stirring speed is adjusted to 250-300r / min at room temperature and stirred for 8-24h until the polysulfone is completely dissolved. The stirring speed is reduced to 70-150r / min, and 3-6g of polyvinylpyrrolidone and 100-150mg of polyvinyl alcohol (PVA) are added respectively. The stirring speed is adjusted to 50-150r / min at room temperature and stirred for 8-24h until the particles are completely dissolved. The stirring speed is reduced to 50-100r / min, and 8-12g of Fe(OH)3 powder is added. The stirring speed is then adjusted to 200-350r / min and stirred for 8-24h to obtain a red slurry-like fluid. The method for preparing Ni(OH)2 casting solution is as follows: Add 35-45g of N-methylpyrrolidone (NMP) to a 100ml three-necked flask, add 6-10g of polysulfone (PSF) at a stirring speed of 50-100r / min, and stir at room temperature at a speed of 250-300r / min for 8-24h until the polysulfone is completely dissolved; reduce the speed to 70-150r / min, add 3-6g of polyvinylpyrrolidone and 100-150mg of polyvinyl alcohol (PVA), and stir at room temperature at a speed of 50-150r / min for 8-24h until the particles are completely dissolved; reduce the speed to 50-100r / min, add 8-12g of Ni(OH)2 powder, and then adjust the speed to 200-350r / min, stirring for 8-24h to obtain a green slurry fluid; The preparation method of Mg(OH)2 casting solution is as follows: Add 40-50g of N-methylpyrrolidone (NMP) to a 100ml three-necked flask, add 6-10g of polysulfone (PSF) at a stirring speed of 50-100r / min, and stir at room temperature at a speed of 250-300r / min for 8-24h until the polysulfone is completely dissolved; reduce the speed to 70-150r / min, add 3-6g of polyvinylpyrrolidone and 100-150mg of polyvinyl alcohol (PVA), and stir at room temperature at a speed of 50-150r / min for 8-24h until the particles are completely dissolved; reduce the speed to 50-100r / min, add 8-12g of Mg(OH)2 powder, and then adjust the speed to 200-350r / min, stirring for 8-24h to obtain a white slurry fluid; The Al(OH)3 casting solution is prepared as follows: 25-35g of N-methylpyrrolidone (NMP) is added to a 100ml three-necked flask. 6-10g of polysulfone (PSF) is added while stirring at 50-100r / min. The stirring speed is adjusted to 250-300r / min at room temperature and stirred for 8-24h until the polysulfone is completely dissolved. The stirring speed is reduced to 70-150r / min, and 3-6g of polyvinylpyrrolidone and 100-150mg of polyvinyl alcohol (PVA) are added respectively. The stirring speed is adjusted to 50-150r / min at room temperature and stirred for 8-24h until the particles are completely dissolved. The stirring speed is reduced to 50-100r / min, and 8-12g of Al(OH)3 powder is added. The stirring speed is then adjusted to 200-350r / min and stirred for 8-24h to obtain a white slurry fluid. c. Degassing of casting solution: Seal the middle neck of the three-necked flask and place it in a vacuum drying oven at room temperature to completely eliminate air bubbles. The degassing methods for different types of casting solutions are exactly the same; d. Film scraping and phase transformation: Cut a PPS mesh and clamp it onto a glass plate. Apply the degassed precursor slurry evenly to the top of the PPS mesh and scrape it from top to bottom at a uniform speed to form a slurry film. Immediately immerse the glass plate with the slurry film into deionized water at room temperature and let it stand until a stable, non-powdering wet composite membrane is formed. The methods for scraping and phase inversion of different types of casting solutions are exactly the same; e. Post-processing: The formed wet membrane is removed from the deionized water, the membrane surface is rinsed with deionized water, and the cleaned wet membrane is placed on clean filter paper or absorbent cloth to absorb excess water from the surface, finally obtaining the alkaline electrolytic water membrane based on non-ampholy hydroxide. The post-treatment methods for different types of casting solutions are exactly the same; In step a, when preparing Fe(OH)3 powder, the ratio of FeCl3 powder to 12% ammonia water is 15.2g:45ml. When preparing Ni(OH)2 powder, the ratio of NiCl2 powder to 12% ammonia water is 16.34 g: 50 ml. When preparing Mg(OH)2 powder, the ratio of MgCl2 powder to 12% ammonia water is 14.0g:35ml. When preparing Al(OH)3 powder, the ratio of AlCl3 powder to 12% ammonia water is 17.09 g: 55 ml.

2. The method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide according to claim 1, characterized in that, In step d, the PPS mesh is left with a gap of 1-3cm from the edge of the glass plate on the left and right sides, and a gap of 2-4cm from the bottom edge of the glass plate.

3. The method for preparing an alkaline water electrolysis membrane based on a non-amphoteric hydroxide according to claim 1 or 2, characterized in that, The thickness of the slurry membrane is 100~400μm.

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