Alkaline electrolyzed water diaphragm based on nickel oxyhydroxide as well as preparation method and application of alkaline electrolyzed water diaphragm

Abstract

The invention discloses an alkaline electrolyzed water diaphragm based on nickel oxyhydroxide and a preparation method and application of the alkaline electrolyzed water diaphragm, and relates to the technical field of composite diaphragms.The alkaline electrolyzed water diaphragm is prepared through a phase inversion method, and nanometer nickel oxyhydroxide NiOOH particles are selected as inorganic nanometer filler; the mass percent of the nickel oxyhydroxide in the membrane casting solution is 15-30%. A strong chemical bond formed by nickel ions and hydroxyl in the hydroxyl nickel oxide crystal endows the material with excellent structural stability, and the material shows excellent solubility resistance, hydrolysis resistance and structural collapse resistance in a strong alkaline electrolysis environment and can tolerate high-concentration OH <-> erosion for a long time; meanwhile, the intrinsic high-oxidation-resistance characteristic is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite diaphragm, and particularly relates to a diaphragm for alkaline electrolysis of water based on nickel oxyhydroxide and a preparation method and application thereof. BACKGROUND

[0002] The diaphragm for alkaline electrolysis of water is one of the core components of an electrolytic cell, and is used to separate the cathode and anode chambers. Under the action of KOH electrolyte and electric current, the diaphragm can realize efficient water molecule splitting to produce hydrogen, and can be widely applied to the fields of large-scale hydrogen production, renewable energy storage, ammonia raw gas production and fuel cell hydrogen filling station, etc.

[0003] The mainstream preparation process of the diaphragm for alkaline electrolysis of water is generally based on a phase inversion method. Generally, zirconium oxide (ZrO2) nanoparticles or surface modified products thereof are added into a casting solution, and then fully mixed and stirred, and then a composite diaphragm with a microporous structure is prepared through a phase inversion process. In addition to the widely used zirconium oxide filler, in recent years, other high-performance inorganic nano fillers (such as cerium oxide CeO2, titanium oxide TiO2, etc.) have also been increasingly concerned and introduced into research and application. These fillers aim to improve the key performances of the diaphragm, such as hydrophilicity, ionic conductivity, chemical stability and mechanical strength, so as to meet the needs of efficient and durable alkaline electrolysis of water to produce hydrogen.

[0004] The pore structure plays a decisive role in the performance of the diaphragm, and its core function is to provide a transmission channel for anions and cations in the electrolyte, to reduce the internal resistance while effectively isolating hydrogen and oxygen, so it is crucial to accurately control the pore size and porosity. If the pore size is too large, the gas tightness of the diaphragm will decrease, and if the pore size is too small, the ion transmission will be hindered. The influence of porosity also follows this rule: too high porosity may damage the gas tightness, and too low porosity will increase the internal resistance. Therefore, the diaphragm needs to be optimized in terms of pore structure to achieve an optimal balance between pore size and porosity, so as to meet the core needs of high gas tightness and low internal resistance. However, the inorganic nano fillers currently used may not achieve instantaneous micro-dispersion, which may cause a series of chain problems, such as easy blockage of micropores by agglomerates, and local pore defects may also cause hydrogen and oxygen to intermingle, significantly increasing the risk of explosion. At the same time, local temperature gradient may induce phase separation of the polysulfone, forming an asymmetric pore structure and causing densification of the surface layer, ultimately causing voltage fluctuations in the electrolytic cell.

[0005] Therefore, it is a technical problem to be solved in the field to provide a diaphragm for alkaline electrolysis of water with low surface resistance and high gas tightness and a simple preparation method. SUMMARY

[0006] In order to solve the above problems, the present application provides a diaphragm for alkaline electrolysis of water based on nickel oxyhydroxide and a preparation method and application thereof. The method has the advantages of simple operation, low cost and large output, and the prepared diaphragm has the characteristics of low surface resistance and high gas tightness.

[0007] To achieve the above object, the application adopts the following technical scheme:

[0008] A kind of basic electrolytic water diaphragm based on nickel oxyhydroxide, the basic electrolytic water diaphragm is prepared using phase inversion method, wherein inorganic nano filler selects nickel oxyhydroxide NiOOH particle.

[0009] Preferably, the mass percentage of the nickel oxyhydroxide nano-particle in the casting solution is 15-30%, and the particle size of the nickel oxyhydroxide nano-particle is 200-250 nm.

[0010] Preferably, the casting solution comprises the following raw materials in mass percentage: N-methyl pyrrolidone: polysulfone: polyvinylpyrrolidone: NiOOH = 55-65%: 15-20%: 5-10%: 10-20%.

[0011] Preferably, the preparation method of the nickel oxyhydroxide nano-particle is as follows:

[0012] After dissolving nickel acetate and urea in distilled water, polyvinylpyrrolidone is added and stirred uniformly, then reacted at 100℃ for 24h, cooled to room temperature, and the product is a greenish NiOOH powder.

[0013] Preferably, the mass ratio of the nickel acetate, the urea, the distilled water and the polyvinylpyrrolidone is 74.7:120.1:100.

[0014] Preferably, the preparation method of the nickel oxyhydroxide nano-particle is as follows:

[0015] After dissolving potassium hydroxide and concentrated ammonia in deionized water, β-Ni(OH)2 is added and stirred uniformly, then heated to 60℃, and potassium persulfate is added in batches for reaction, until the reaction solution turns black and no oxygen bubbles are generated, and the product is a black NiOOH powder.

[0016] Preferably, the mass-volume ratio of the potassium hydroxide, the concentrated ammonia, the deionized water and the β-Ni(OH)2 is 7g:8mL:80mL:10g.

[0017] According to the preparation method of the basic electrolytic water diaphragm based on nickel oxyhydroxide, the preparation method specifically comprises the following steps:

[0018] (1) Preparation of casting solution: polysulfone powder, polyvinyl alcohol and polyvinylpyrrolidone are sequentially added in N-methyl pyrrolidone to form a uniform transparent solution, then nickel oxyhydroxide nano-particle is added and stirred uniformly to obtain the casting solution;

[0019] (2) After defoaming the casting solution, a uniform liquid film is formed on the substrate, and then immersed in deionized water for phase inversion to form a wet composite diaphragm with microporous structure;

[0020] (3) The wet composite diaphragm is washed and dried to obtain a basic electrolytic water diaphragm based on nickel oxyhydroxide.

[0021] Preferably, the stirring time in step (1) is 8-24h;

[0022] The phase inversion time in step (2) is 5-30min;

[0023] The drying conditions in step (3) are 50-60℃ for 12-24h.

[0024] The application of the above-mentioned basic electrolytic water diaphragm based on nickel oxyhydroxide in the field of electrolytic water.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) Breakthrough in material stability: The strong chemical bond between nickel ions and hydroxyl groups in the nickel oxyhydroxide crystals used in the present application endows it with excellent structural stability. In a strong alkaline electrolytic environment, the material exhibits excellent resistance to dissolution, hydrolysis and structural collapse, and can withstand high-concentration OH - erosion for a long time; at the same time, it has intrinsic high oxidation resistance, can resist high potential impact of >1.5V in the anode area, avoid electrochemical degradation, and increase the service life of the diaphragm by >40%;

[0027] (2) Upgrade of ion transport efficiency: The NiOOH surface of the present application is rich in hydroxyl functional groups, which can construct a fast transmission channel for hydroxyl ions (OH - ). The conductivity of hydroxyl ions is about 2 times higher than that of traditional inorganic fillers (such as ZrO2 / CeO2 / TiO2), which significantly reduces the surface resistance of the diaphragm and reduces the working voltage of the electrolytic cell by 8-12%;

[0028] (3) Expansion of formulation tolerance: The present application breaks through the material dispersion bottleneck by strengthening the mixing process, so that the component ratio of the casting solution can be adjusted in a wide range. This feature supports the customized development of diaphragm performance (such as high mechanical strength type / high ion conduction type);

[0029] (4) Comprehensive performance improvement: The present application realizes the synergistic innovation of materials and processes, so that the ion conductivity of the diaphragm is ≥0.12S / cm (80℃, 30% KOH), the tensile strength is >20MPa (5 times higher than that of pure PSF membrane), and the performance decay is <5% after 1000h of accelerated aging at 30% KOH, 80℃. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. The drawings in the description are only embodiments of the present application.

[0031] Figure 1 XRD pattern of NiOOH powder in Example 1 of the present application;

[0032] Figure 2 Thermogravimetric analysis pattern of NiOOH powder in Example 1 of the present application;

[0033] Figure 3 Scanning electron microscope pattern of NiOOH powder in Example 1 of the present application;

[0034] Figure 4 Scanning electron microscope pattern of the surface of NiOOH / PSF composite microporous separator in Example 1 of the present application;

[0035] Figure 5 Scanning electron microscope pattern of the cross section of NiOOH / PSF composite microporous separator in Example 1 of the present application;

[0036] Figure 6 Tensile strength test pattern of NiOOH / PSF composite microporous separator in Example 1 of the present application;

[0037] Figure 7 Contact angle test pattern of NiOOH / PSF composite microporous separator in Example 1 of the present application;

[0038] Figure 8 Surface resistance test pattern of NiOOH / PSF composite microporous separator in Example 1 of the present application;

[0039] Figure 9 XRD pattern of NiOOH powder in Example 2 of the present application;

[0040] Figure 10 Thermogravimetric analysis pattern of NiOOH powder in Example 2 of the present application;

[0041] Figure 11 Scanning electron microscope pattern of NiOOH powder in Example 2 of the present application;

[0042] Figure 12 Scanning electron microscope pattern of the surface of NiOOH / PSF / PVP composite microporous separator in Example 2 of the present application;

[0043] Figure 13 Scanning electron microscope pattern of the cross section of NiOOH / PSF / PVP composite microporous separator in Example 2 of the present application;

[0044] Figure 14 Figure for tensile strength test of NiOOH / PSF / PVP composite microporous separator in Example 2 of the present application;

[0045] Figure 15 Figure for contact angle test of NiOOH / PSF / PVP composite microporous separator in Example 2 of the present application;

[0046] Figure 16 Figure for surface resistance test of NiOOH / PSF / PVP composite microporous separator in Example 2 of the present application;

[0047] Figure 17 Figure for cell voltage test of NiOOH / PSF / PVP composite microporous separator in Example 2 of the present application;

[0048] Figure 18 Figure for tensile strength test of NiOOH / PSF composite microporous separator in Example 3 of the present application;

[0049] Figure 19 Figure for contact angle test of NiOOH / PSF composite microporous separator in Example 3 of the present application;

[0050] Figure 20 Figure for surface resistance test of NiOOH / PSF composite microporous separator in Example 3 of the present application;

[0051] Figure 21 Figure for tensile strength test of NiOOH / PSF / PVP composite microporous separator in Example 4 of the present application;

[0052] Figure 22 Figure for contact angle test of NiOOH / PSF / PVP composite microporous separator in Example 4 of the present application;

[0053] Figure 23 Figure for surface resistance test of NiOOH / PSF / PVP composite microporous separator in Example 4 of the present application. DETAILED DESCRIPTION

[0054] Embodiments of the present application are described below, examples of which are shown in the accompanying drawings, the embodiments described with reference to the drawings are exemplary and are intended to explain the present application, and are not understood as limiting the present application.

[0055] Example 1

[0056] The present application provides a preparation method of a nickel oxyhydroxide-based alkaline electrolytic water separator, specifically comprising the following steps:

[0057] (1) 74.7 mg of nickel acetate (NiAc) and 120.1 mg of urea were dissolved in 50 mL of distilled water, then 0.1 g of polyvinylpyrrolidone (PVP) was added, the obtained solution was magnetically stirred at room temperature for 30 min, then transferred to a 100 mL polytetrafluoroethylene lined autoclave, the autoclave was placed in an oven and reacted at 100°C for 24 h, then naturally cooled to room temperature, the solution was transferred to a centrifuge tube, centrifuged at 6000 rpm for 5 min, the precipitate was collected and washed with water and ethanol alternately for three times, finally, the product was placed in a vacuum drying oven and dried at 50°C for 12 h to obtain a green NiOOH powder; Figure 1 Figure 1 is an XRD pattern of the NiOOH powder, Figure 2 Figure 2 is a thermogravimetric analysis pattern of the NiOOH powder, Figure 3 Figure 3 is a scanning electron microscope pattern of the NiOOH powder, it can be seen from the figure that the NiOOH powder is successfully synthesized; the particle size of the synthesized NiOOH powder is 200 nm-250 nm, the NiOOH nanosheet has a regular hexagonal shape; the decomposition temperature of the NiOOH powder is about 155°C;

[0058] (2) Preparation of casting solution: 12.5 g of N-methyl pyrrolidone (NMP) was added to a 100 mL three-necked flask, a mechanical stirring paddle was installed in the middle of the flask, 4.5 g of polysulfone (PSF) powder was slowly added to the NMP under a stirring rate of 200 rpm, and stirred until it was basically dissolved, then 4 g of NMP and 10 mg of polyvinyl alcohol (PVA) were mixed in a sample bottle, which was fully dissolved in an oil bath at 95°C, then added to the mixed solution of NMP and PSF, then 3 g of polyvinylpyrrolidone (PVP) was added, and the stirring was continued until the PVP was completely dissolved, forming a uniform transparent solution; then 6 g of prepared NiOOH powder was added, the stirring rate was increased to 300 rpm (to ensure sufficient dispersion and not introduce too many air bubbles), and the stirring was continued for 12 h to make the NiOOH nanoparticles uniformly dispersed in the polymer solution, obtaining the casting solution;

[0059] (3) The prepared casting solution was transferred to a suitable container and placed in a vacuum drying box, vacuumized at room temperature for 12 h until no obvious bubbles were generated in the casting solution, the fully defoamed casting solution was poured onto a clean and flat glass substrate, a 300 μm doctor blade was used to uniformly coat, forming a uniform liquid film, immediately immersing the substrate with the wet film into deionized water at room temperature for coagulation bath, keeping the immersed state for 15 min, making the solvent (NMP) exchange with water, and the polymer precipitated to form a wet composite separator with a microporous structure;

[0060] (4) The wet composite diaphragm with micro-porous structure coagulated and shaped is taken out from the coagulation bath, the membrane surface is washed with a large amount of deionized water to completely remove the residual solvent and possible impurities, the washed wet membrane is placed on a clean filter paper to absorb the excess water on the surface, and then the wet membrane is transferred to a vacuum drying oven for drying at 50°C for 12h to completely remove the water in the membrane, thereby obtaining the final NiOOH / PSF composite micro-porous diaphragm for alkaline electrolytic water, and the dried diaphragm should be stored in a desiccator for standby use;

[0061] Figure 4 SEM image of the surface of the NiOOH / PSF composite micro-porous diaphragm, Figure 5 SEM image of the cross section of the NiOOH / PSF composite micro-porous diaphragm, as shown in the figure, the surface of the diaphragm is uniformly attached with NiOOH nanoparticles, and the film pore size is about 10μm; the cross section is mostly sponge-like hole;

[0062] Figure 6 Tensile strength test diagram of the NiOOH / PSF composite micro-porous diaphragm, and Table 1 is the tensile strength test parameters and data of the NiOOH / PSF composite micro-porous diaphragm, which shows that the tensile strength of the NiOOH / PSF composite micro-porous diaphragm is 29.28Mpa.

[0063] Table 1 Tensile strength test parameters and data of the NiOOH / PSF composite micro-porous diaphragm

[0064] Figure 7 Contact angle test diagram of the NiOOH / PSF composite micro-porous diaphragm, as shown in the figure, the contact angle of the diaphragm is 60.3°, which has good hydrophilicity;

[0065] Figure 8 Surface resistance test diagram of the NiOOH / PSF composite micro-porous diaphragm, and Table 2 is the surface resistance test data of the NiOOH / PSF composite micro-porous diaphragm, which shows that the surface resistance of the NiOOH / PSF composite micro-porous diaphragm is 0.324Ω cm -2 (blank group is a group without diaphragm, the resistance value of the diaphragm with the area specified in the national standard and the resistance value of the potassium hydroxide solution with the same concentration and area, the difference between the two multiplied by the area of the diaphragm is the surface resistance of the diaphragm); Table 3 is the alkali absorption rate test data of the NiOOH / PSF composite micro-porous diaphragm, the method refers to the electronic industry standard SJ / T 10171.7-91⟪Determination of diaphragm alkali absorption rate⟫, the alkali absorption rate is about 400%, the high alkali absorption rate of the diaphragm means that it has rich micro-porous structure and hydrophilic groups inside, which can quickly and massively absorb and store electrolyte, which reflects that the composite micro-porous diaphragm has extremely high alkali absorption capacity and liquid affinity, which is beneficial to the transmission of hydroxyl ions and the discharge of product gas.

[0066] Table 2 NiOOH / PSF composite microporous separator surface resistance test data

[0067] The measured surface resistance of the composite separator is 0.324 Ω cm -2 , the measured thickness of the film is 0.16 mm;

[0068] Table 3 NiOOH / PSF composite microporous separator alkali absorption rate test data

[0069] Note: Samples H1 and H2 are samples of different batches of NiOOH / PSF composite microporous separators.

[0070] Example 2

[0071] The present application provides a preparation method of a nickel oxyhydroxide-based alkaline electrolytic water separator, specifically comprising the following steps:

[0072] (1) In a 150 mL beaker placed in an ice bath, 80 mL of deionized water is added, 7 g of potassium hydroxide (KOH) and 8 mL of concentrated ammonia are dissolved, then 10 g of β-Ni(OH)2 powder is added to the solution, and mechanical stirring is carried out at room temperature for 30 min. After stirring is completed, the beaker is transferred to a water bath and heated to 60°C and maintained at this temperature, stirring is maintained, and potassium persulfate (K2S2O8) is added in six batches, 6.3 g each, with an interval of about 10 min. When the reaction solution turns black and no oxygen bubbles are generated, stop stirring; vacuum filter the reaction mixture, wash the obtained solid precipitate with 80°C hot water repeatedly until the pH value of the filtrate reaches 7-8, and finally, place the product in a 60°C vacuum drying oven for drying for 12 h to obtain black NiOOH powder; Figure 9 is the XRD pattern of NiOOH powder, Figure 10 is the thermogravimetric analysis pattern of NiOOH powder, Figure 11 is the scanning electron microscope image of NiOOH powder, as can be seen from the figure: NiOOH powder is successfully synthesized; NiOOH nanosheets exhibit obvious flake or needle-like morphology; the decomposition temperature is about 220°C;

[0073] (2) Preparation of casting solution: 12.5 g of N-methyl pyrrolidone was added to a 100 mL three-necked flask, a mechanical stirring paddle was installed in the middle of the flask, 4.5 g of polysulfone powder was slowly added to the NMP under a stirring rate of 200 rpm, and stirred until it was basically dissolved, then 4 g of NMP and 10 mg of polyvinyl alcohol (PVA) were mixed in a sample bottle, after being fully dissolved in an oil bath at 95°C, it was added to the mixed solution of NMP and PSF, then 3 g of polyvinylpyrrolidone (PVP) was added, and the stirring was continued until the PVP was completely dissolved to form a uniform transparent solution; then 6 g of prepared NiOOH powder was added, and the stirring rate was adjusted to 300 rpm (to ensure sufficient dispersion and not introduce too many air bubbles), and the stirring was continued for 12 h to make the NiOOH nanoparticles uniformly dispersed in the polymer solution to obtain the casting solution;

[0074] (3) The prepared casting solution was transferred to a suitable container and placed in a vacuum drying oven, and vacuumized at room temperature for 12 h until no obvious bubbles were generated in the casting solution; the fully defoamed casting solution was poured onto a clean and flat glass substrate, and a 300 μm doctor blade was used for uniform coating to form a uniform liquid film, and the substrate with the wet film was immediately immersed in a deionized water coagulation bath at room temperature, and kept immersed for 15 min to make the solvent (NMP) exchange with the non-solvent (water), and the polymer precipitated to form a wet composite separator with a microporous structure;

[0075] (4) The wet composite separator with a microporous structure coagulated and shaped was taken out of the coagulation bath, the membrane surface was washed with a large amount of deionized water to completely remove the residual solvent and possible impurities, the cleaned wet membrane was placed on a clean filter paper to absorb the excess water on the surface, and then the wet membrane was transferred to a vacuum drying oven for drying at 50°C for 12 h to completely remove the water in the membrane to obtain the final NiOOH / PSF / PVP composite microporous separator for alkaline electrolytic water, and the dried separator should be stored in a desiccator for standby use;

[0076] Figure 12 SEM image of the surface of the NiOOH / PSF / PVP composite microporous separator, Figure 13 SEM image of the cross section of the NiOOH / PSF / PVP composite microporous separator, as shown in the figure, the surface of the separator has a large number of pores, and the surface is uniformly distributed with NiOOH nanoparticles; the cross-sectional sponge-like pores are more, and the nanoparticles are well dispersed, and the proportion of NiOOH in the dry membrane is 15%-25%;

[0077] Figure 14 Tensile strength test diagram of the NiOOH / PSF / PVP composite microporous separator, and Table 4 is the tensile strength test parameters and data of the NiOOH / PSF / PVP composite microporous separator, and it can be seen that the tensile strength is 21.01 Mpa.

[0078] Table 4 NiOOH / PSF / PVP composite microporous separator tensile strength test parameters and data

[0079] Figure 15 The contact angle test diagram of the NiOOH / PSF / PVP composite microporous separator is shown in the figure, and the contact angle is 68.9°, which has good hydrophilicity;

[0080] Figure 16 The surface resistance test diagram of the NiOOH / PSF / PVP composite microporous separator is shown in the figure, and Table 5 is the surface resistance test data of the NiOOH / PSF / PVP composite microporous separator. It can be seen that the surface resistance of the NiOOH / PSF / PVP composite microporous separator is 0.209 Ω cm -2 (blank group is a group without separator, the resistance value of the separator with the area specified in the national standard and the resistance value of the potassium hydroxide solution with the same concentration and area, the product of the difference between the two and the area of the separator is the surface resistance of the separator); Table 6 is the alkali absorption rate test data of the NiOOH / PSF / PVP composite microporous separator, and the alkali absorption rate is about 260%. The alkali absorption rate of 260% indicates that the separator still has good liquid affinity and sufficient liquid absorption capacity, which can ensure the basic ion conductivity requirement; but compared with Example 1, the decrease of the alkali absorption rate means that the pore size of the separator becomes larger, the pore shape changes, more through holes appear instead of closed pores, and the surface hydrophilic group density is relatively reduced.

[0081] Table 5 NiOOH / PSF / PVP composite microporous separator surface resistance test data

[0082] The surface resistance of the composite separator is 0.209 Ω cm -2 ;

[0083] Table 6 NiOOH / PSF / PVP composite microporous separator alkali absorption rate test data

[0084] Note: Samples H1 and H2 are samples of different batches of NiOOH / PSF composite microporous separators.

[0085] Figure 17 The cell voltage test diagram of the NiOOH / PSF / PVP composite microporous separator in Example 2 is shown in the figure, and the cathode and anode of the electrolytic cell both use nickel felt as the catalyst; as shown in the figure, the NiOOH / PSF / PVP composite microporous separator applied to water electrolysis obtains a high current density of 5000 A / m 2 @2V, which is significantly better than the performance of commercial separators (3500 A / m 22V~UTP500).

[0086] Example 3

[0087] The present application provides a preparation method of alkaline electrolytic water diaphragm based on nickel oxyhydroxide, specifically comprising the following steps:

[0088] (1) 74.7 mg of nickel acetate (NiAc) and 120.1 mg of urea were dissolved in 50 mL of distilled water, then 0.1 g of polyvinylpyrrolidone (PVP) was added, the obtained solution was magnetically stirred at room temperature for 30 min, then transferred to a 100 mL polytetrafluoroethylene lined autoclave, the autoclave was placed in an oven, reacted at 100°C for 24 h, then naturally cooled to room temperature, the solution was transferred to a centrifuge tube, centrifuged at 6000 rpm for 5 min, the precipitate was collected and washed with water and ethanol alternately for three times, finally, the product was placed in a vacuum drying oven and dried at 50°C for 12 h, obtaining a green NiOOH powder;

[0089] (2) Preparation of casting solution: 20 g of N-methyl pyrrolidone was added to a 100 mL three-necked flask, a mechanical stirring paddle was installed in the middle of the flask, 8 g of polysulfone powder was slowly added to the NMP under a stirring rate of 200 rpm, stirred until it was basically dissolved, then 6 g of NMP was mixed with 10 mg of polyvinyl alcohol (PVA) in a sample bottle, after fully dissolved in a 95°C oil bath, it was added to the mixed solution of NMP and PSF, then 2 g of polyvinylpyrrolidone (PVP) was added, continue to stir until the PVP is completely dissolved, forming a uniform transparent solution; then 4 g of prepared NiOOH powder was added, the stirring rate was adjusted to 300 rpm (to ensure sufficient dispersion and not introduce too many air bubbles), continue to stir for 12 h, so that the NiOOH nanoparticles are uniformly dispersed in the polymer solution, obtaining the casting solution;

[0090] (3) The prepared casting solution was transferred to a suitable container and placed in a vacuum drying oven, vacuumed for 12 h at room temperature until no obvious bubbles were generated in the casting solution; the fully degassed casting solution was poured onto a clean and flat glass substrate, a 300 μm doctor blade was used to uniformly coat, forming a uniform liquid film, immediately immerse the substrate with the wet film into a deionized water coagulation bath at room temperature, keep it immersed for 15 min, so that the solvent (NMP) and the non-solvent (water) exchange, the polymer precipitates, forming a wet composite diaphragm with a microporous structure;

[0091] (4) The wet composite diaphragm with micro-porous structure coagulated and shaped is taken out from the coagulation bath, the membrane surface is washed with a large amount of deionized water to completely remove the residual solvent and possible impurities, the washed wet membrane is placed on a clean filter paper to absorb the excess water on the surface, and then the wet membrane is transferred to a vacuum drying oven for drying at 50°C for 12h to completely remove the water in the membrane, thereby obtaining the final NiOOH / PSF composite micro-porous diaphragm for alkaline electrolytic water, and the dried diaphragm should be stored in a desiccator for standby use;

[0092] Figure 18 Figure 2 is a tensile strength test diagram of the NiOOH / PSF composite micro-porous diaphragm, and Table 7 is tensile strength test parameters and data of the NiOOH / PSF composite micro-porous diaphragm, and it can be known that the tensile strength thereof is 16.53Mpa;

[0093] Table 7 Tensile strength test parameters and data of the NiOOH / PSF composite micro-porous diaphragm

[0094] Figure 19 Figure 3 is a contact angle test diagram of the NiOOH / PSF composite micro-porous diaphragm, and it can be known from the figure that the contact angle thereof is 100.9°;

[0095] Figure 20 Figure 4 is a surface resistance test diagram of the NiOOH / PSF composite micro-porous diaphragm, and Table 5 is surface resistance test data of the NiOOH / PSF composite micro-porous diaphragm, and it can be known that the surface resistance thereof is 0.173Ω cm -2 (blank group is a group without diaphragm, the difference between the resistance value of the diaphragm with the area specified in the national standard and the resistance value of the potassium hydroxide solution with the same concentration and area, and the product of the diaphragm area, is the surface resistance of the diaphragm); Table 9 is alkali absorption rate test data of the NiOOH / PSF composite micro-porous diaphragm, and the average alkali absorption rate is about 311%, which indicates that the NiOOH / PSF composite material system itself has strong inherent hydrophilicity and porous characteristics, and can provide sufficient ion transmission channels for alkaline batteries.

[0096] Table 8 Surface resistance test data of the NiOOH / PSF composite micro-porous diaphragm

[0097] The surface resistance of the composite diaphragm is 0.173Ω cm -2 ;

[0098] Table 9 Alkali absorption rate test data of the NiOOH / PSF composite micro-porous diaphragm

[0099] Note: The sample H1 and the sample H2 are samples of different batches of NiOOH / PSF composite micro-porous diaphragms.

[0100] Example 4

[0101] The present application provides a preparation method of alkaline electrolytic water diaphragm based on nickel oxyhydroxide, specifically comprising the following steps:

[0102] (1) In a 150 mL beaker placed in an ice bath, 80 mL of deionized water was added, 7 g of potassium hydroxide (KOH) and 8 mL of concentrated ammonia were dissolved, then 10 g of β-Ni(OH)2 powder was added to the solution, and mechanical stirring was carried out at room temperature for 30 min. After stirring was completed, the beaker was transferred to a water bath and heated to 60°C and maintained at this temperature, stirring was maintained, and potassium persulfate (K2S2O8) was added in six batches, 6.3 g each, with an interval of about 10 min. When the reaction solution turned black and no oxygen bubbles were generated, stirring was stopped; the reaction mixture was vacuum filtered, and the obtained solid precipitate was repeatedly washed with hot water at 80°C until the pH value of the filtrate reached 7-8. Finally, the product was placed in a 60°C vacuum drying oven for drying for 12 h, obtaining black NiOOH powder;

[0103] (2) Preparation of casting solution: 20 g of N-methyl pyrrolidone was added to a 100 mL three-necked flask, a mechanical stirring paddle was installed in the middle of the flask, and 8 g of polysulfone powder was slowly added to the NMP under a stirring rate of 200 rpm, and stirred until it was basically dissolved. Then 6 g of NMP was mixed with 10 mg of polyvinyl alcohol (PVA) in a sample bottle, which was fully dissolved in an oil bath at 95°C, and then added to the mixed solution of NMP and PSF. Then 2 g of polyvinylpyrrolidone (PVP) was added, and the stirring was continued until the PVP was completely dissolved, forming a uniform transparent solution. Then 4 g of prepared NiOOH powder was added, and the stirring rate was adjusted to 300 rpm (to ensure sufficient dispersion and not introduce too many air bubbles), and the stirring was continued for 12 h to make the NiOOH nanoparticles uniformly dispersed in the polymer solution, obtaining the casting solution;

[0104] (3) The prepared casting solution was transferred to a suitable container and placed in a vacuum drying oven, and vacuumed for 12 h at room temperature until no obvious bubbles were generated in the casting solution; the fully degassed casting solution was poured onto a clean and flat glass substrate, and a 300 μm doctor blade was used for uniform coating, forming a uniform liquid film. Immediately immerse the substrate with the wet film into a deionized water coagulation bath at room temperature, keep it submerged for 15 min, so that the solvent (NMP) and the non-solvent (water) exchange, the polymer precipitates, forming a wet composite diaphragm with a microporous structure;

[0105] (4) The wet composite diaphragm with micro-porous structure coagulated and shaped is taken out from the coagulation bath, the membrane surface is washed with a large amount of deionized water to completely remove the residual solvent and possible impurities, the washed wet membrane is placed on a clean filter paper to absorb the excess water on the surface, and then the wet membrane is transferred to a vacuum drying oven for drying at 50°C for 12h to completely remove the water in the membrane, thereby obtaining the final NiOOH / PSF composite micro-porous diaphragm for alkaline electrolytic water, and the dried diaphragm should be stored in a desiccator for standby use;

[0106] Figure 21 Figure 6 is a tensile strength test diagram of the NiOOH / PSF / PVP composite micro-porous diaphragm, and Table 10 is tensile strength test parameters and data of the NiOOH / PSF / PVP composite micro-porous diaphragm, and it can be known that the tensile strength is 22.24Mpa.

[0107] Table 10 Tensile strength test parameters and data of NiOOH / PSF / PVP composite micro-porous diaphragm

[0108] Figure 22 Figure 7 is a contact angle test diagram of the NiOOH / PSF / PVP composite micro-porous diaphragm, and it can be known from the figure that the contact angle is 102.4°.

[0109] Figure 23 Figure 8 is a surface resistance test diagram of the NiOOH / PSF / PVP composite micro-porous diaphragm, and Table 11 is surface resistance test data of the NiOOH / PSF / PVP composite micro-porous diaphragm, and it can be known that the surface resistance is 0.606Ω cm. -2 (blank group is a group without diaphragm, the resistance value of the diaphragm with the area specified in the national standard and the resistance value of the potassium hydroxide solution with the same concentration and area, the difference between the two multiplied by the area of the diaphragm is the surface resistance of the diaphragm); Table 12 is the alkali absorption rate test data of the NiOOH / PSF / PVP composite micro-porous diaphragm, and the average alkali absorption rate is 340%, which means that the diaphragm has a very high ion conductivity potential.

[0110] Table 11 Surface resistance test data of NiOOH / PSF / PVP composite micro-porous diaphragm

[0111] The surface resistance of the composite diaphragm is measured to be 0.606Ω cm -2 ;

[0112] Table 12 Alkali absorption rate test data of NiOOH / PSF / PVP composite micro-porous diaphragm

[0113] Note: Samples H1 and H2 are samples of different batches of NiOOH / PSF / PVP composite micro-porous diaphragm.

[0114] The above examples are only used to illustrate the technical solutions of the present application, but not to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those ordinarily skilled in the art should understand: the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An alkaline water electrolysis membrane based on nickel hydroxyl oxide, characterized in that, The alkaline water electrolysis membrane is prepared by phase inversion method, wherein the inorganic nanofiller is selected as nano-nickel hydroxyl oxide (NiOOH).

2. The alkaline water electrolysis membrane based on nickel hydroxyl oxide according to claim 1, characterized in that, The mass percentage of the nano-hydroxy nickel oxide in the casting solution is 10-20%, and the particle size of the nano-hydroxy nickel oxide is 200-250 nm.

3. The alkaline water electrolysis membrane based on nickel hydroxyl oxide according to claim 2, characterized in that, The casting solution comprises the following raw materials by mass percentage: N-methylpyrrolidone: polysulfone: polyvinylpyrrolidone: NiOOH = 55-65%: 15-20%: 5-10%: 10-20%.

4. The alkaline water electrolysis membrane based on nickel hydroxyl oxide according to claim 1, characterized in that, The preparation method of the nano-nickel hydroxyl oxide is as follows: Nickel acetate and urea are dissolved in distilled water, then polyvinylpyrrolidone is added and stirred until homogeneous. The mixture is then reacted at 80-100℃ for 12-36 hours and cooled to room temperature to obtain the product, which is a matcha-green NiOOH powder.

5. The alkaline water electrolysis membrane based on nickel hydroxyl oxide according to claim 4, characterized in that, The mass ratio of the nickel acetate, the urea, the distilled water, and the polyvinylpyrrolidone is 74.7:120.1:

100.

6. The alkaline water electrolysis membrane based on nickel hydroxyl oxide according to claim 1, characterized in that, The preparation method of the nano-nickel hydroxyl oxide is as follows: Dissolve potassium hydroxide and concentrated ammonia in deionized water, then add β-Ni(OH)2 and stir until homogeneous. Then heat to 45-65℃ and add potassium persulfate in batches to react. The reaction continues until the reaction solution turns black and no oxygen bubbles are produced. The product obtained is black NiOOH powder.

7. The alkaline water electrolysis membrane based on nickel hydroxyl oxide according to claim 6, characterized in that, The mass-to-volume ratio of the potassium hydroxide, the concentrated ammonia, the deionized water, and the β-Ni(OH)2 is 7g:8mL:80mL:10g.

8. A method for preparing an alkaline water electrolysis membrane based on nickel hydroxyl oxide according to any one of claims 1-7, characterized in that, Specifically, the following steps are included: (1) Preparation of casting solution: Polysulfone powder, polyvinyl alcohol and polyvinylpyrrolidone are added to N-methylpyrrolidone in sequence to form a uniform and transparent solution. Then, nano-nickel hydroxyl oxide is added and stirred evenly to obtain the casting solution. (2) After the casting solution is degassed, a uniform liquid film is formed on the substrate, and then it is immersed in deionized water for phase transformation to form a wet composite membrane with a microporous structure. (3) The wet composite membrane is washed and dried to obtain an alkaline water electrolysis membrane based on nickel hydroxy oxide.

9. The method for preparing an alkaline water electrolysis membrane based on nickel hydroxyl oxide according to claim 8, characterized in that, The stirring time in step (1) is 8-24 hours; The phase transformation time described in step (2) is 5-30 min; The drying conditions described in step (3) are: drying at 50-60℃ for 12-24 hours.

10. The application of the alkaline water electrolysis membrane based on nickel hydroxyl oxide according to any one of claims 1-7 in the field of water electrolysis.

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