Ionic solvent diaphragm, alkaline water electrolysis device, preparation method and application

Abstract

The invention discloses an ionic solvent diaphragm, an alkaline water electrolysis device, a preparation method and application. The preparation method of the ionic solvent diaphragm comprises the following steps: contacting a casting membrane solution containing polybenzimidazole and an organic solvent with a reinforcing material with a pore structure to prepare a diaphragm precursor; and carrying out phase inversion and deprotonation on the diaphragm precursor to prepare the ionic solvent diaphragm. According to the preparation method of the ion solvent diaphragm, the ion solvent diaphragm which is provided with a compact surface layer and an internal porous structure and contains polybenzimidazole is prepared through a phase inversion method, and the ionic conduction performance of the diaphragm can be improved by providing an extra proton conduction path through introduction of a reinforcing material of the porous structure. The prepared ionic solvent diaphragm has high hydrophilicity and hydroxyl conductivity, excellent electrical properties and good mechanical properties. The provided ionic solvent diaphragm has excellent water electrolysis performance when being applied to the alkaline water electrolysis device.

Description

Technical Field

[0001] The invention belongs to the field of alkaline water electrolysis anion exchange membranes and relates to an ion solvent diaphragm, an alkaline water electrolysis device, a preparation method and an application. Background Art

[0002] When deployed together with green and renewable primary energy sources, hydrogen energy is one of the most promising components of a future independent of fossil fuels. Energy from the sun, wind, waves / tidal and other emission-free sources can power water electrolyzers (WE), which can produce green hydrogen without generating carbon emissions. In alkaline water electrolysis technology, the ion-solvent diaphragm plays a vital role. It is the key channel for ion transport between the cathode and the anode. During the alkaline water electrolysis process using potassium hydroxide solution as the electrolyte, the ions produced at the cathode need to migrate to the anode through the ion-solvent diaphragm to ensure the continuous electrolysis reaction. However, the current ion-solvent diaphragms have poor electrical conductivity and mechanical strength. Summary of the invention

[0003] In view of the problem that the current ion solvent diaphragm has poor conductivity and mechanical strength, the present invention provides an ion solvent diaphragm, an alkaline water electrolysis device, a preparation method and application.

[0004] In some embodiments, a method for preparing an ionic solvent membrane is provided, comprising the following steps:

[0005] The membrane precursor is prepared by contacting a casting solution containing polybenzimidazole and an organic solvent with a reinforcing material having a porous structure;

[0006] The membrane precursor is subjected to phase transformation and deprotonation to prepare the ion solvent membrane.

[0007] In some embodiments, in the method for preparing an ionic solvent membrane provided, the mass volume ratio of polybenzimidazole to organic solvent in the casting solution is (8-15) g:100 mL, calculated by feed amount.

[0008] In some embodiments, in the method for preparing an ionic solvent membrane provided, the thickness of the reinforcing material is 100 um to 200 um.

[0009] In some embodiments, the method for preparing the ionic solvent membrane provides one or more of the following features:

[0010] The polybenzimidazole comprises one or more of poly(2,5-benzimidazole) (AB-PBI), poly(2,2'-phenyl-5,5'-benzimidazole) (PBI-4 N), poly(2,2'-(m-phenyl)-5,5'-benzimidazole) (m-PBI), pyridine bridged PBI (Py-PBIs) and poly(4,4'-diphenyl ether-5,5'-benzimidazole) (OPBI);

[0011] The organic solvent comprises one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.

[0012] In some embodiments, in the method for preparing an ionic solvent membrane provided, the reinforcing material comprises a polyolefin mesh;

[0013] Optionally, the polyolefin net comprises one or more of a polyethylene net, a polypropylene net, a polytetrafluoroethylene net and a polyvinylidene fluoride net;

[0014] Optionally, the mesh size of the polyolefin mesh is 20-100 meshes.

[0015] In some embodiments, the method for preparing the ionic solvent membrane provides one or more of the following features:

[0016] In the phase inversion step, the phase inversion solvent is one or more of ethanol, methanol and water;

[0017] In the deprotonation step, deprotonation is performed using an alkali solution, wherein the alkali solution comprises a KOH solution with a concentration of 20 wt % to 50 wt %.

[0018] In some embodiments, an ionic solvent membrane is provided, which is prepared by the preparation method.

[0019] In some embodiments, the thickness of the ionic solvent membrane is 200 um to 600 um.

[0020] In some embodiments, there is provided a use of the ionic solvent membrane in alkaline water electrolysis or in a device for preparing alkaline water electrolysis.

[0021] In some embodiments, an alkaline water electrolysis device is provided, comprising an alkaline electrolyzer system, wherein the alkaline electrolyzer system comprises the ion solvent membrane.

[0022] The preparation method of the ionic solvent membrane provided by the present invention utilizes a phase inversion method to prepare an ionic solvent membrane containing polybenzimidazole having a dense surface layer and an internal porous structure. The introduction of a reinforcing material of the porous structure can improve the ionic conductivity of the membrane by providing an additional proton conduction path. The prepared ionic solvent membrane has high hydrophilicity and hydroxide conductivity, excellent electrical properties, and good mechanical properties. The provided ionic solvent membrane is applied to an alkaline water electrolysis device and has excellent water electrolysis performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the implementation methods and examples of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for use in the description of the implementation methods or examples. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0024] Figure 1 is a flow chart of the preparation of an ionic solvent membrane in one embodiment;

[0025] Figure 2 The polarization curves of the ionic solvent membranes in Example 1 and Comparative Example 1 in alkaline electrolyzed water are shown in FIG. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0028] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0029] The terms "and / or", "or / and", and "and / or" used in this application include any one of two or more related listed items, and also include any and all combinations of related listed items, and the arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and "a combination of A and B".

[0030] In the present application, "plurality", "multiple", "multiple times", "multiples", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0031] The terms "combination thereof", "any combination thereof", "any combination thereof" and the like used in this application include all suitable combinations of any two or more of the listed items.

[0032] In this application, the "suitable" mentioned in "suitable combination", "suitable method", "any suitable method", etc. is based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0033] In the present application, "preferred", "better", "more preferred" and "suitable" are only used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of the present application.

[0034] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0035] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0036] In the present invention, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0037] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0038] In the present application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In this article, it is equivalent to directly listing each integer, such as t is an integer selected from 1 to 10, indicating that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0039] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0040] In the present application, % (w / w) and wt% both represent weight percentage, % (v / v) refers to volume percentage, and % (w / v) refers to mass volume percentage.

[0041] The "room temperature" in this application generally refers to 5°C to 30°C, preferably 25±5°C.

[0042] Most WEs in use today are alkaline water electrolyzers and proton exchange membrane water electrolyzers (PEMWEs), the former of which have inherently limited current density due to inevitable gas crossover, operate with corrosive (7M) alkaline solutions, and require large installation spaces, while the latter require expensive and scarce precious metal-based electrocatalysts. Anion exchange membrane water electrolyzers (AEMWEs) are an emerging technology that aims to combine the advantages of both into one device while overcoming their respective limitations. AEMWEs offer higher operating current density and pressure, similar Faradaic efficiency (>90%), fast ramp / load tracking response, and use of non-precious metal catalysts and pure water feed compared to PEMWEs. Unfortunately, the main challenges that remain for AEMWEs and corresponding ion transport membranes (including alkaline membranes and proton exchange membranes) are hydrogen production efficiency under operating conditions, long-term stability, and cost-effectiveness, which present key issues that need to be addressed as a top priority. Relatively speaking, traditional alkaline water electrolysis technology is superior in cost-effectiveness and durability, and shows a wider range of applicability, because it can use more economical and more stable non-precious metal catalysts in alkaline media.

[0043] Dense polymer films perform well in terms of gas barrier properties and conductivity of alkaline electrolytes, because there are no obvious pores to promote the passage of substances, but rely on the dissolution and diffusion mechanism of molecules, and can only achieve relatively high ionic conductivity by reducing the film thickness or other chemical modification methods. The membrane with a dense cortex and internal porous structure prepared by the phase inversion method has a higher ionic conductivity, but due to the higher internal porosity, its mechanical strength is poor.

[0044] In some embodiments, a method for preparing an ionic solvent membrane is provided, comprising the following steps:

[0045] The membrane precursor is prepared by contacting a casting solution containing polybenzimidazole and an organic solvent with a reinforcing material having a porous structure;

[0046] The membrane precursor is subjected to phase transformation and deprotonation to prepare the ion solvent membrane.

[0047] In some embodiments, a method for preparing an ionic solvent membrane is provided, comprising the following steps:

[0048] S100: contacting a casting solution containing polybenzimidazole and an organic solvent with a reinforcing material having a porous structure to prepare a diaphragm precursor;

[0049] S200: performing phase transformation and deprotonation on the membrane precursor to prepare the ionic solvent membrane.

[0050] In some embodiments, in the provided method for preparing an ionic solvent membrane, in step S100, based on the feed amount, the mass volume ratio of polybenzimidazole and the organic solvent in the casting solution is (8-15) g:100 mL. For example, the mass volume ratio of polybenzimidazole and the organic solvent in the casting solution can be 8 g:100 mL, 9 g:100 mL, 10 g:100 mL, 11 g:100 mL, 12 g:100 mL, 13 g:100 mL, 14 g:100 mL, 15 g:100 mL or a range selected from any two of the foregoing ratios.

[0051] In some embodiments, in the method for preparing an ionic solvent membrane provided, in step S100, the thickness of the reinforcing material is 100um~200um. For example, the thickness of the reinforcing material can be 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um, 200um or a range selected from any two of the foregoing ratios.

[0052] In some embodiments, in the method for preparing an ionic solvent membrane provided, in step S100, the polybenzimidazole comprises one or more of poly(2,5-benzimidazole) (AB-PBI), poly(2,2'-phenyl-5,5'-benzimidazole) (PBI-4N), poly(2,2'-(isophenyl)-5,5'-benzimidazole) (m-PBI), pyridine-bridged PBI (Py-PBIs) and poly(4,4'-diphenyl ether-5,5'-benzimidazole) (OPBI).

[0053] In some embodiments, in the method for preparing an ionic solvent membrane provided, in step S100, the polybenzimidazole is poly(2,2'-(m-phenyl)-5,5'-benzimidazole).

[0054] In some embodiments, the method for preparing poly(2,2'-(m-phenyl)-5,5'-benzimidazole) comprises the following steps:

[0055] In the presence of a solvent, the aromatic tetraamine and the aromatic diacid undergo a condensation reaction, the temperature of the condensation reaction is 150°C~200°C, the time is 4h~24h, and the molar ratio of the aromatic tetraamine and the aromatic diacid is (1~3): (1~3).

[0056] In some embodiments, in the method for preparing poly(2,2'-(m-phenyl)-5,5'-benzimidazole), the solvent comprises polyphosphoric acid.

[0057] In some embodiments, in the preparation method of poly(2,2'-(m-phenyl)-5,5'-benzimidazole), in order to improve the polycondensation effect, before the polycondensation reaction occurs, the solvent PPA can be heated to 120°C~150°C under stirring and nitrogen atmosphere, and maintained at 120°C~150°C for 30~60 min to remove moisture from polyphosphoric acid (PPA).

[0058] In some embodiments, in the method for preparing an ionic solvent membrane provided, in step S100, the organic solvent comprises one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.

[0059] In some embodiments, in the provided method for preparing an ionic solvent membrane, in step S100, the reinforcing material comprises a polyolefin mesh.

[0060] In some embodiments, the polyolefin net comprises one or more of a polyethylene net, a polypropylene net, a polytetrafluoroethylene net, and a polyvinylidene fluoride net.

[0061] In some embodiments, the mesh number of the polyolefin mesh is 20 mesh to 100 mesh. For example, the mesh number of the polyolefin mesh can be 20 mesh, 30 mesh, 40 mesh, 50 mesh, 60 mesh, 70 mesh, 80 mesh, 90 mesh, 100 mesh or a range selected from any two ratios of the foregoing.

[0062] In some embodiments, in the method for preparing an ionic solvent membrane provided, in step S200, in the phase inversion step, the phase inversion solvent is one or more of ethanol, methanol and water.

[0063] In some embodiments, in the method for preparing an ionic solvent membrane provided, in step S200, in the deprotonation step, deprotonation is performed using an alkaline solution, and the alkaline solution contains a KOH solution with a concentration of 20 wt% to 50 wt%.

[0064] In some embodiments, an ionic solvent membrane is provided, which is prepared by the aforementioned preparation method.

[0065] In some embodiments, the thickness of the ionic solvent membrane is 200 um to 600 um. For example, the thickness of the ionic solvent membrane can be 200 um, 300 um, 400 um, 500 um, 600 um or a range selected from any two ratios of the foregoing.

[0066] In some embodiments, the provided ion solvent membrane is used in alkaline water electrolysis or in a device for preparing alkaline water electrolysis.

[0067] In some embodiments, an alkaline water electrolysis device is provided, including an alkaline electrolyzer system, wherein the alkaline electrolyzer system includes an ion solvent membrane.

[0068] The polyolefin mesh has good mechanical strength and toughness. Using it as a reinforcing material to prepare an ion solvent membrane containing polybenzimidazole through a phase inversion method can enhance the mechanical properties of the ion solvent membrane and increase the durability of the ion solvent membrane. The prepared ion solvent membrane can be used under harsh conditions.

[0069] The ion diaphragm prepared by the present invention exhibits excellent water electrolysis performance, excellent mechanical strength and mechanical stability, has important significance in scientific research and industrial applications, and expands new possibilities for the application of water electrolysis technology.

[0070] The technical solution provided by the present invention is further described in detail below through examples.

[0071] The polybenzimidazole used in the embodiment is poly(2,2'-(m-phenyl)-5,5'-benzimidazole), namely m-PBI, which is prepared by the following method:

[0072] 1. Raw material preparation: Weigh 10.7 g 3,3',4,4'-biphenyltetramine (TAB) and 7.6 g isophthalic acid (IPA), ensuring the molar ratio is 1:1. Prepare 100 mL 85% polyphosphoric acid (PPA) as solvent and catalyst.

[0073] 2. Mix the reactants: Add TAB and IPA to 100 mL PPA and stir well to form a uniform mixture.

[0074] 3. Heating polymerization: Heat the mixture to 200°C and keep it at this temperature for 6 hours. During the reaction, stir continuously to ensure uniform reaction.

[0075] 4. Cooling and separation: After the reaction is completed, the reaction mixture is cooled to room temperature. The reaction mixture is slowly poured into a large amount of deionized water (about 1 L) to precipitate the polymer. The precipitate is collected by filtration and washed with deionized water several times until the filtrate is neutral. The washed precipitate is dried at 80°C for several hours to obtain m-PBI powder.

[0076] Pretreatment: In order to improve the polycondensation effect, PPA (100 ml) can be heated to 120 °C and maintained for 30 min under stirring and nitrogen atmosphere before the polycondensation reaction to remove moisture from polyphosphoric acid (PPA).

[0077] The thickness of polypropylene mesh, polyethylene mesh and polybutylene mesh is 200 microns. Purchase link: https: / / shop250482668.taobao.com / shop / view_shop.htm?spm=a1z09.2.0.0.62d42e8d047n2d&user_number_id=507857989.

[0078] 1. Preparation of ionic solvent membrane

[0079] Example 1

[0080] (1) Preparation of casting solution

[0081] First, 5 g of poly (2,2'-(isophenylene)-5,5'-benzimidazole) was added to 50 ml of DMAc to prepare a 10 wt% solution, and stirred at 130 ° C for 6 to 8 hours; cooled to room temperature for use;

[0082] (2) Phase transformation film casting

[0083] First, a 40-mesh polypropylene mesh was cut into a 15*5 cm square and fixed in the middle of a scraper that could move up and down. After the scraper gap was determined to be 600 μm, scraping was performed. Deionized water was used for rapid phase inversion. After multiple washes with deionized water, a polybenzimidazole diaphragm supported by a polyolefin mesh was obtained. The membrane was taken out of the deionized water and immersed in a 30 wt% KOH solution for deprotonation to prepare an ionic solvent diaphragm with a thickness of 400 μm.

[0084] Example 2

[0085] (1) Preparation of casting solution

[0086] First, 5 g of poly (2,2'-(isophenylene)-5,5'-benzimidazole) was added to 50 ml of DMAc to prepare a 10 wt% solution, and stirred at 130 ° C for 6-8 hours; cooled to room temperature for use;

[0087] (2) Phase transformation film casting

[0088] First, a polyethylene mesh with a mesh size of 40 was cut into a square of 15*5 cm and fixed in the middle of a scraper that could move up and down. After determining that the scraper gap was 600 μm, scraping was performed, and phase inversion was quickly performed with deionized water. After washing with deionized water several times, a polybenzimidazole diaphragm supported by a polyolefin mesh was obtained. The membrane was taken out of the deionized water and immersed in a 30 wt% KOH solution for deprotonation, thereby preparing an ionic solvent diaphragm with a thickness of 400 μm.

[0089] Example 3

[0090] (1) Preparation of casting solution

[0091] First, 5 g of poly (2,2'-(isophenylene)-5,5'-benzimidazole) was added to 50 ml of DMAc to prepare a 10 wt% solution, and stirred at 130 ° C for 6-8 hours; cooled to room temperature for use;

[0092] (2) Phase transformation film casting

[0093] First, a polybutylene mesh with a mesh size of 40 was cut into a square of 15*5 cm and fixed in the middle of a scraper that could move up and down. After determining that the scraper gap was 600 μm, scraping was performed, and phase inversion was quickly performed with deionized water. After washing with deionized water several times, a polybenzimidazole diaphragm supported by a polyolefin mesh was obtained. The membrane was taken out of the deionized water and immersed in a 30 wt% KOH solution for deprotonation, thereby preparing an ionic solvent diaphragm with a thickness of 400 μm.

[0094] Comparative Example 1

[0095] (1) Preparation of casting solution

[0096] First, 5 g of poly (2,2'-(isophenylene)-5,5'-benzimidazole) was added to 50 ml of DMAc to prepare a 10 wt% solution, and stirred at 130 ° C for 6 to 8 hours; cooled to room temperature for use;

[0097] (2) Phase transformation film casting

[0098] First, the casting liquid was cast on a glass plate, and the scraper gap was adjusted to 600 μm before scraping. The phase was quickly inverted with deionized water, and the membrane was peeled off the glass plate. The polybenzimidazole diaphragm was obtained after being washed with deionized water several times, and then immersed in a 30 wt% KOH solution for deprotonation to prepare an ionic solvent diaphragm with a thickness of 200 μm.

[0099] 2. Performance Test

[0100] The electrical conductivity and mechanical properties of the ionic solvent membranes prepared in Example 1 and Comparative Example 1 were tested.

[0101] (1) Conductivity test

[0102] The membrane was immersed in a 30 wt % KOH aqueous solution for 24 h and then cut into a circular shape with a diameter of 3.5 cm. The initial conductivity of the circular sample was measured using a Gamry electrochemical workstation Reference 3000 impedance analyzer.

[0103] (2) Mechanical strength test

[0104] The membrane was cut into a 1.5*15 cm square and immersed in a 30 wt% KOH aqueous solution for 24 hours. The rectangular ion solvent membrane was taken out from the KOH aqueous solution after immersion, and the excess liquid on the surface was wiped off. The opposite ends of the short side of the PBI membrane were ensured to be aligned in the fixture of the tensile testing machine to avoid lateral sliding or twisting during the stretching process. The tensile testing machine (ZQ-990L) was started to stretch the ion solvent membrane at a preset rate of 10 mm / min until the tensile strength of the membrane was less than 0.05 MPa and the test was stopped.

[0105] (3) Alkaline electrolyzed water performance test

[0106] The prepared membrane was used as an ion solvent membrane and deprotonated in 30wt% KOH for 12h. The nickel foam and Pt / C carbon cloth were used as cathodes and the Ni / Fe catalyst nickel foam was used as anode. They were all cut into squares of 3.0×3.0cm for further use. The flow field area of ​​a single cell was 9cm 2 The membrane, OER catalyst and HER catalyst were assembled into a battery together with a polytetrafluoroethylene insulating gasket. In the homemade electrolysis system, the battery was connected, and a 1M KOH aqueous solution was circulated at 60 ml / min. When the temperature reached 55°C, the current was 1000 A / m 2 Activate for half an hour at a current density of , gradually increase the current, record the corresponding potential, and plot the recorded potential and the corresponding current density data into a graph, with the horizontal axis being the potential (V) and the vertical axis being the current density (A / m²)

[0107] Test Results

[0108] Figure 2 The polarization curves of alkaline electrolysis of water of the membranes prepared in Example 1 and Comparative Example 1 are shown in Figure 1, where the horizontal axis is the current density and the vertical axis is the voltage. In the test environment of 55°C and 1M KOH, the membrane prepared in Example 1 maintains about 6000Am at 1.8V. -2 The current density of Comparative Example 1 was maintained at about 8000Am at 1.8V. -2 of current density.

[0109] Table 1 shows the mechanical properties of wet films of Example 1 and Comparative Example 1 measured at room temperature.

[0110] Table 1

[0111]

[0112] As can be seen from Table 1, the tensile strength of the ion solvent membrane in Example 1 is 12.3MPa, and the elongation at break is 23.4%; the tensile strength of the ion solvent membrane in Comparative Example 1 is 1.0MPa, and the elongation at break is 27.5%. The mechanical strength of the ion solvent membrane prepared in Comparative Example 1 is too poor to be used in industry; from the mechanical property data, it can be seen that the mechanical properties of the polypropylene mesh reinforced membrane have been significantly improved. This shows that the introduction of the polyolefin mesh promotes the mechanical stability of the membrane to a certain extent while ensuring the basic battery performance.

[0113] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims, and the description and drawings may be used to interpret the content of the claims.

Claims

1. A method for preparing an ionic solvent membrane, characterized in that: The following steps are included: The membrane precursor is prepared by contacting a casting solution containing polybenzimidazole and an organic solvent with a reinforcing material having a porous structure; The membrane precursor is subjected to phase transformation and deprotonation to prepare the ion solvent membrane.

2. The preparation method according to claim 1, characterized in that: Calculated by feed amount, the mass volume ratio of polybenzimidazole to organic solvent in the casting solution is (8-15) g:100 mL.

3. The preparation method according to claim 1 or 2, characterized in that: The thickness of the reinforcing material is 100um~200um.

4. The preparation method according to any one of claims 1 to 3, characterized in that Meet one or more of the following characteristics: The polybenzimidazole comprises one or more of poly(2,5-benzimidazole), poly(2,2'-phenyl-5,5'-benzimidazole), poly(2,2'-(m-phenyl)-5,5'-benzimidazole), pyridine bridged polybenzimidazole and poly(4,4'-diphenyl ether-5,5'-benzimidazole); The organic solvent comprises one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide.

5. The preparation method according to any one of claims 1 to 4, characterized in that The reinforcing material comprises a polyolefin mesh; Optionally, the polyolefin net comprises one or more of a polyethylene net, a polypropylene net, a polytetrafluoroethylene net and a polyvinylidene fluoride net; Optionally, the mesh size of the polyolefin mesh is 20-100 meshes.

6. The preparation method according to any one of claims 1 to 5, characterized in that Meet one or more of the following characteristics: In the phase inversion step, the phase inversion solvent is one or more of ethanol, methanol and water; In the deprotonation step, deprotonation is performed using an alkali solution, wherein the alkali solution comprises a KOH solution with a concentration of 20 wt % to 50 wt %.

7. An ionic solvent membrane, characterized in that It is prepared by the preparation method according to any one of claims 1 to 6.

8. The preparation method according to claim 7, characterized in that: The thickness of the ion solvent membrane is 200um~600um.

9. Use of the ionic solvent diaphragm according to claim 7 or 8 in alkaline water electrolysis or in an alkaline water electrolysis device.

10. An alkaline water electrolysis device, characterized in that: It comprises an alkaline electrolyzer system, wherein the alkaline electrolyzer system comprises the ionic solvent membrane according to claim 7 or 8.

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