Flow battery proton membrane and preparation method thereof

Abstract

The invention provides a flow battery proton membrane and a preparation method thereof, and the method comprises the following steps: S1, dissolving polybenzimidazole, an inorganic substance and a dispersant in an organic solvent, and mixing to obtain a membrane casting solution; s2, casting the membrane casting solution on the surface of a flat carrier to form a membrane casting solution thin layer; and S3, carrying out phase inversion on the membrane casting liquid thin layer in a phase inversion solution to prepare the proton conduction membrane. According to the flow battery proton membrane and the preparation method thereof provided by the invention, the bottleneck problem of large internal resistance of a traditional homogeneous polybenzimidazole membrane can be obviously improved, and the proton conduction rate of the flow battery proton membrane can be substantially enhanced essentially, so that the voltage efficiency and the energy efficiency of the flow battery proton membrane are obviously improved; the efficiency and the conductivity are improved while the film forming thickness is increased, the mechanical property is also obviously improved, and the stability is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid flow batteries, and in particular relates to a liquid flow battery proton membrane and a preparation method thereof. Background Art

[0002] With the limited resources of non-renewable energy such as coal, oil, and natural gas, and the corresponding emission pollution and environmental problems becoming more and more prominent, how to reasonably and efficiently utilize renewable energy has become the focus of social attention. For example, renewable energy such as wind energy and solar energy are affected by harsh conditions such as seasons, weather, and geographical factors, and have obvious instability and discontinuity. The power generated fluctuates greatly, which will have a great impact on the power grid. Therefore, with the rapid rise of renewable energy such as wind energy and solar energy and the smart grid industry, the development of supporting energy storage technologies such as flow battery technology has become a key issue.

[0003] In the liquid flow battery, only ions of different valence states achieve the purpose of charge and discharge cycle through valence rise and fall, without other phase changes, thus having the advantages of long battery life, good charge and discharge performance, zero emission and no pollution, the system can be fully automatic and closed, very stable and safe, etc. Liquid flow batteries have a long service life, good charge and discharge performance, and can be deeply discharged without damaging the battery. Liquid flow batteries have a large degree of freedom in site selection, and most of the battery components are cheap carbon materials. The battery energy efficiency can be as high as 75%-85%, which makes it increasingly widely concerned.

[0004] The proton conducting membrane is one of the core components of the flow battery. It is used to isolate the positive and negative electrolytes when flowing through the battery stack, avoiding the self-discharge caused by the penetration of ions of different valence states and resulting in capacity loss, while allowing proton migration to ensure charge balance. The performance and structure of the proton conducting membrane determine the efficiency and cycle stability of the flow battery. The proton conducting membrane required for the flow battery should have the following characteristics: ① Low ion interpenetration rate, small cross contamination, reduced battery self-discharge, and improved energy efficiency. ② High proton permeability, low membrane resistance, and improved voltage efficiency. ③ It has a certain mechanical strength, is resistant to chemical corrosion and electrochemical oxidation, and ensures a long cycle life. ④ The water penetration is small when the battery is charged and discharged, maintaining the water balance of the positive and negative electrolytes.

[0005] Polybenzimidazole (PBI) is a class of fully aromatic compounds with excellent properties such as high thermal stability, mechanical stability, flame retardancy, etc. It is considered to be the most suitable exchange membrane material to replace the traditional Nafion membrane. However, PBI also has shortcomings as a proton exchange membrane, mainly due to its obvious disadvantages such as high resistance, low proton conductivity, low voltage efficiency and poor solubility. Summary of the invention

[0006] In view of the above problems, the present invention provides a proton membrane for a liquid flow battery and a method for preparing the same.

[0007] The method for preparing a proton membrane for a flow battery provided by the present invention comprises the following steps:

[0008] S1, dissolving polybenzimidazole, inorganic substance, and dispersant in an organic solvent, and mixing to obtain a casting solution;

[0009] S2, casting the casting liquid on the surface of a flat carrier to form a thin layer of the casting liquid;

[0010] S3, subjecting the thin layer of the casting liquid to phase transformation in a phase transformation solution to prepare a proton conducting membrane.

[0011] further,

[0012] The inorganic substance is titanium dioxide, cerium oxide, tungsten trioxide, or zirconium dioxide.

[0013] further,

[0014] The dispersant is silicate or phosphate.

[0015] further,

[0016] The dispersant is sodium tripolyphosphate, sodium silicate, or tripropyl phosphate silicone oil.

[0017] further,

[0018] The solvent is N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide.

[0019] further,

[0020] The mass percentage content of the polybenzimidazole is in the range of 8wt%-16wt%;

[0021] The molecular weight of the polybenzimidazole is in the range of 60,000 to 220,000;

[0022] The inorganic particle size range is 10 nanometers to 50 nanometers;

[0023] The mass percentage content of the inorganic substance is in the range of 0.5wt%-5wt%;

[0024] The mass percentage content of the dispersant is in the range of 0.2wt%-0.3wt%;

[0025] In step S1, the mixing temperature range is configured to be 60-90 degrees Celsius;

[0026] The temperature range of the solution for phase inversion in step S3 is 5-50 degrees Celsius.

[0027] further,

[0028] The flat carrier includes a flat glass, a metal plate, a polymer plate, or a ceramic plate with a flat and smooth surface;

[0029] The thickness of the thin layer of casting liquid is in the range of 100-600 microns.

[0030] further,

[0031] The phase inversion solution is one of saturated solutions of potassium chloride, sodium chloride and sodium hydroxide.

[0032] further,

[0033] The mass percentage content of the polybenzimidazole is 12wt%;

[0034] The molecular weight range of the polybenzimidazole is 150,000;

[0035] The inorganic particle size is 12 nanometers;

[0036] The mass percentage content of the inorganic substance is 2wt%;

[0037] The mass percentage content of the dispersant is 0.25wt%;

[0038] In step S1, the mixing temperature range is configured to be 80 degrees Celsius;

[0039] The temperature of the solution for phase inversion in step S3 is 10 degrees Celsius;

[0040] The thickness of the thin layer of casting liquid is in the range of 400 microns.

[0041] The present invention also provides a liquid flow battery proton membrane, which is prepared by adopting the above-mentioned liquid flow battery proton membrane preparation method.

[0042] The method for preparing a proton membrane for a flow battery provided by the present invention can significantly improve the bottleneck problem of large internal resistance of a traditional polybenzimidazole membrane by introducing a hydrophilic inorganic substance and making it uniformly dispersed in a membrane liquid; by forming a membrane through phase transformation in a high-concentration solution, the traditional polybenzimidazole membrane is changed from a dense ion exchange membrane to a sponge-like membrane inside the membrane, which can substantially enhance the proton conduction rate and significantly improve its voltage efficiency and energy efficiency; by introducing a hydrophilic inorganic substance in combination with phase transformation, the film thickness is increased while the efficiency and conductive properties are improved, the mechanical properties are also significantly improved, and the stability is guaranteed, thereby avoiding the problem that the traditional polybenzimidazole membrane can only ensure its conductive capacity by reducing the thickness of the membrane due to its large internal resistance, but the physical and mechanical properties of the membrane are poor due to the too thin thickness, and industrialization is very difficult and it is difficult to achieve continuous production.

[0043] The liquid flow battery proton membrane provided by the present invention is resistant to chemical corrosion, has stable performance and obvious improvement effect under strong acid and alkali conditions, and has high ion conductivity. The liquid flow battery proton membrane preparation method provided by the present invention uses polybenzimidazole as a raw material, dopes it with inorganic substances that improve hydrophilicity, and prepares a porous proton conductive membrane by phase transformation in a high-concentration solution. The process is simple and easy to industrialize and continuously produce, which greatly reduces the manufacturing cost of the liquid flow battery.

[0044] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 A flow chart of a method for preparing a proton membrane for a flow battery according to an embodiment of the present invention is shown;

[0047] Figure 2 An electron microscope image of a cross section of a proton membrane of a flow battery provided by the present invention is shown;

[0048] Figure 3 The long cycle charge and discharge performance diagram of the traditional polybenzimidazole film is shown;

[0049] Figure 4 The long cycle charge and discharge performance diagram of the proton membrane of the flow battery provided by the present invention is shown. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", "third", etc. in the specification and claims of this application or the above-mentioned figures are used to distinguish different objects, not to describe a specific order or a primary and secondary relationship. "Multiple" appearing in this application refers to more than two (including two).

[0052] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] Figure 1 This is a flow chart of the method for preparing the proton membrane of a flow battery provided by the present invention. Figure 1 The method for preparing a proton membrane for a liquid flow battery comprises the following steps.

[0054] S1. Dissolve polybenzimidazole, inorganic substances such as inorganic oxides, and dispersants in an organic solvent according to a certain ratio, and mix at a suitable temperature to obtain a casting solution.

[0055] in,

[0056] The mass percentage content of polybenzimidazole is in the range of 8wt%-16wt%, preferably 12wt%. When the mass percentage content of polybenzimidazole in the casting solution is in the above range, the porosity of the obtained film material is appropriate. If the mass percentage content of polybenzimidazole in the casting solution is too small, it is not easy to cast into a film. If the mass percentage content of polybenzimidazole in the casting solution is too large, the pores of the obtained film material are too dense, resulting in high internal resistance of the film, high viscosity and difficulty in film formation;

[0057] The molecular weight of the polybenzimidazole is in the range of 60,000 to 220,000, preferably 150,000. The viscosity of the film produced by the polybenzimidazole with a molecular weight in the above range is appropriate, which is convenient for factory production;

[0058] The inorganic substance is TiO 2 (TiO2), CeO 2 (Cerium oxide), WO 3 (tungsten trioxide), or ZrO 2(zirconium dioxide), the particle size range is 10 nanometers (nm)-50nm, such as 12 nanometers, which makes it evenly dispersed in the casting solution. Too large a particle size will affect the uniformity and flatness of the film;

[0059] The mass percentage of the inorganic substance is 0.5wt%-5wt%, preferably 2wt%. Too high or too low a mass percentage of the inorganic substance will affect the conductive properties and mechanical strength of the film.

[0060] The dispersant is a silicate or a phosphate, specifically, sodium tripolyphosphate, sodium silicate, or tripropyl phosphate silicone oil. The mass percentage content of each of the dispersants is in the range of 0.2wt%-0.3wt%, preferably 0.25wt%.

[0061] The solvent includes N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide;

[0062] The suitable temperature, i.e. the mixing temperature, is in the range of 60-90 degrees Celsius (°C), preferably 80°C. When the heating temperature is within the above range, the selectivity and resistance of the prepared membrane are moderate.

[0063] S2. Casting the prepared casting liquid on the surface of a flat carrier at a suitable thickness to form a thin layer of the casting liquid.

[0064] in,

[0065] The flat carrier includes a flat glass, a metal plate, a polymer plate, or a ceramic plate with a flat and smooth surface;

[0066] The thickness of the thin layer of the casting liquid is in the range of 100-600 microns (um), preferably 400 microns. When the thickness of the thin layer of the casting liquid is within the above range, the internal resistance and selectivity of the prepared film are moderate. If the thickness of the thin layer of the casting liquid is too small, the film thickness will be thin, the mechanical properties will be poor, and the selectivity will be low. If the thickness of the thin layer of the casting liquid is too large, the internal resistance of the film will be too high.

[0067] S3. Phase-inverting the thin layer of the casting liquid in a high-concentration phase-inverting solution to prepare a porous proton-conducting membrane, wherein the porous proton-conducting membrane is a proton membrane of a liquid flow battery.

[0068] in,

[0069] The phase inversion solution can be a saturated solution of potassium chloride (KCl), sodium chloride (NaCl), or sodium hydroxide (NaOH), and the phase inversion solution determines the pore size of the porous membrane. The temperature range of the phase inversion solution is 5-50°C, such as 10°C.

[0070] The present invention also provides a liquid flow battery proton membrane, which is prepared by using the liquid flow battery proton membrane preparation method.

[0071] The liquid flow battery proton membrane provided by the present invention is a proton conductive membrane, which can be used in liquid flow batteries, semi-liquid flow batteries, fuel cells, and water electrolysis processes.

[0072] Example 1

[0073] This embodiment provides a method for preparing a proton membrane for a flow battery, comprising the following steps:

[0074] 1.1. Dissolve polybenzimidazole, inorganic substances such as inorganic oxides, and dispersants in an organic solvent in a certain ratio and mix at a suitable temperature to obtain a casting solution.

[0075] in,

[0076] The mass percentage of polybenzimidazole is 16wt%;

[0077] The molecular weight of the polybenzimidazole is 220,000;

[0078] The inorganic material includes TiO 2 (TiO2), CeO 2 (Cerium oxide), WO 3 (Tungsten trioxide), ZrO 2 (zirconium dioxide) etc., with a particle size of 50 nm;

[0079] The mass percentage of the inorganic substance is 5wt%;

[0080] The dispersant is sodium tripolyphosphate, and the mass percentage content of the dispersant is 0.3wt%, wherein sodium tripolyphosphate can be replaced by sodium silicate or tripropyl phosphate silicone oil;

[0081] The solvent is N,N-dimethylacetamide, which can be replaced by N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide;

[0082] The suitable temperature, i.e. the mixing temperature, is 90°C.

[0083] 1.2. Cast the obtained casting liquid on the surface of a flat carrier at a suitable thickness to form a thin layer of casting liquid.

[0084] in,

[0085] The flat carrier is a flat glass with a flat and smooth surface, and the flat glass can be replaced by a metal plate, a polymer plate, or a ceramic plate;

[0086] The thickness of the thin layer of casting liquid is in the range of 600um.

[0087] 1.3. The thin layer of the casting liquid is subjected to phase inversion in a high concentration phase inversion solution to prepare a porous proton conducting membrane.

[0088] in,

[0089] The phase inversion solution is a saturated KCl solution. The solution temperature for phase inversion is 50 degrees Celsius. The saturated KCl solution can be replaced by a saturated solution of NaCl or NaOH.

[0090] Example 2

[0091] 2.1. Dissolve polybenzimidazole, inorganic substances such as inorganic oxides, and dispersants in an organic solvent in a certain ratio and mix at a suitable temperature to obtain a casting solution.

[0092] in,

[0093] The mass percentage of polybenzimidazole is 12wt%;

[0094] The molecular weight of the polybenzimidazole is 150,000;

[0095] The inorganic material includes TiO 2 (TiO2), CeO 2 (Cerium oxide), WO 3 (Tungsten trioxide), ZrO 2 (zirconium dioxide) etc., with a particle size of 12 nm;

[0096] The mass percentage of the inorganic substance is 2wt%;

[0097] The dispersant is sodium tripolyphosphate, and the mass percentage content of the dispersant is 0.25wt%, wherein sodium tripolyphosphate can be replaced by sodium silicate or tripropyl phosphate silicone oil;

[0098] The solvent is N,N-dimethylacetamide, which can be replaced by N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide;

[0099] The suitable temperature, i.e. the mixing temperature, is 80°C.

[0100] 2.2. Cast the obtained casting liquid on the surface of a flat carrier at a suitable thickness to form a thin layer of casting liquid.

[0101] in,

[0102] The flat carrier is a flat glass with a flat and smooth surface, and the flat glass can be replaced by a metal plate, a polymer plate, or a ceramic plate;

[0103] The thickness of the thin layer of casting liquid is in the range of 400um.

[0104] 2.3. The thin layer of the casting liquid is subjected to phase transformation in a high concentration phase transformation solution to prepare a porous proton conducting membrane.

[0105] in,

[0106] The phase inversion solution is a saturated KCl solution. The solution temperature for phase inversion is 10 degrees Celsius. The saturated KCl solution can be replaced by a saturated solution of NaCl or NaOH.

[0107] Example 3

[0108] This embodiment provides a method for preparing a proton membrane for a flow battery, comprising the following steps:

[0109] 3.1. Dissolve polybenzimidazole, inorganic substances such as inorganic oxides, and dispersants in an organic solvent in a certain ratio and mix at a suitable temperature to obtain a casting solution.

[0110] in,

[0111] The mass percentage of polybenzimidazole is 8wt%;

[0112] The molecular weight of the polybenzimidazole is 60,000;

[0113] The inorganic material includes TiO 2 (TiO2), SiO 2 (Silicon oxide), WO 3 (Tungsten trioxide), ZrO 2 (zirconium dioxide) etc., with a particle size of 10 nm;

[0114] The mass percentage of the inorganic substance is 0.5wt%;

[0115] The dispersant is sodium tripolyphosphate, and the mass percentage content of the dispersant is 0.2wt%, wherein sodium tripolyphosphate can be replaced by sodium silicate or tripropyl phosphate silicone oil;

[0116] The solvent is N,N-dimethylacetamide, which can be replaced by N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide;

[0117] The suitable temperature, i.e. the mixing temperature range, is 60°C.

[0118] 3.2. Cast the obtained casting liquid on the surface of a flat carrier at a suitable thickness to form a thin layer of casting liquid.

[0119] in,

[0120] The flat carrier is a flat glass with a flat and smooth surface, and the flat glass can be replaced by a metal plate, a polymer plate, or a ceramic plate;

[0121] The thickness of the thin layer of casting liquid is in the range of 100 um.

[0122] 3.3. The thin layer of the casting liquid is subjected to phase inversion in a high concentration phase inversion solution to prepare a porous proton conducting membrane.

[0123] in,

[0124] The phase inversion solution is a saturated KCl solution. The solution temperature for phase inversion is 5 degrees Celsius. The saturated KCl solution can be replaced by a saturated solution of NaCl or NaOH.

[0125] Comparative Example:

[0126] (1) dissolving 10 wt % of polybenzimidazole in N,N-dimethylacetamide and stirring at 80° C. for 3 hours to prepare a casting solution;

[0127] (2) casting the casting solution prepared in step (1) on the surface of the flat glass into a thin layer of casting solution with a thickness of 100 μm;

[0128] (3) The film obtained in step (2) is placed in an oven at 80° C. and dried for 1 hour to obtain a dense ion exchange membrane after the solvent is dried.

[0129] Figure 2 This is an electron microscope image of a cross section of a proton membrane of a flow battery provided by the present invention. Figure 2 It can be seen that the interior of the proton membrane of the liquid flow battery is sponge-like, so that the membrane can greatly enhance the proton conduction rate, thereby significantly improving its voltage efficiency and energy efficiency.

[0130] The present invention compares the performance of the proton conductive membrane prepared in Example 2 and the proton conductive membrane prepared in the comparative example for all-vanadium redox flow battery: controlling 150 mA (milliampere) cm (centimeter) at room temperature -2 The current density was 0.0447 W / m, and the proton conducting membrane prepared in Example 2 and the proton conducting membrane prepared in the comparative example were used to carry out battery charge / discharge cycle measurement. The results were as follows: Figure 4 and Figure 3 As shown, Figure 3 This is a long cycle charge and discharge performance diagram of a traditional polybenzimidazole membrane (i.e., a proton conducting membrane obtained in the comparative example). Figure 4The long cycle charge and discharge performance diagram of the proton membrane of the flow battery provided by the present invention (the proton conductive membrane prepared in Example 2). By comparison, it can be seen that the proton conductive membrane of the comparative example has better current efficiency, but the resistance is too large and the surface resistance is high, resulting in a pressure efficiency of only 81.3%, so the final energy efficiency is only 80.5%. The average coulomb efficiency, voltage efficiency and energy efficiency of the proton conductive membrane prepared in Example 2 are 94.69%, 88.32%, and 83.63%, respectively. The voltage efficiency and energy efficiency of the battery are significantly improved. At this point, it can be explained that the porous membrane prepared by phase transformation by adding a suitable inorganic oxide to the polybenzimidazole membrane has better performance.

[0131] The liquid flow battery proton membrane provided by the present invention is a high-efficiency polybenzimidazole porous membrane, which is prepared by phase conversion, so that the traditional polybenzimidazole membrane can improve the disadvantage of excessive internal resistance after being doped with hydrophilic inorganic substances, and then the voltage efficiency of the membrane can be improved after phase conversion. Compared with the traditional polybenzimidazole membrane, it has higher conductivity, higher stability and higher efficiency.

[0132] The method for preparing the proton membrane of a liquid flow battery provided by the present invention has a simple process and is easy to be scaled up industrially and to carry out continuous production.

[0133] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions 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 invention.

Claims

1. A method for preparing a proton membrane for a flow battery, characterized in that: The following steps are involved: S1, dissolving polybenzimidazole, inorganic substance, and dispersant in an organic solvent, and mixing to obtain a casting solution; S2, casting the casting liquid on the surface of a flat carrier to form a thin layer of the casting liquid; S3, subjecting the thin layer of the casting liquid to phase transformation in a phase transformation solution to prepare a proton conducting membrane.

2. The method for preparing a proton membrane for a flow battery according to claim 1, characterized in that: The inorganic substance is titanium dioxide, cerium oxide, tungsten trioxide, or zirconium dioxide.

3. The method for preparing a proton membrane for a flow battery according to claim 2, characterized in that: The dispersant is silicate or phosphate.

4. The method for preparing a proton membrane for a flow battery according to claim 3, characterized in that: The dispersant is sodium tripolyphosphate, sodium silicate, or tripropyl phosphate silicone oil.

5. The method for preparing a proton membrane for a flow battery according to claim 4, characterized in that: The solvent is N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, or dimethyl sulfoxide.

6. The method for preparing a proton membrane for a flow battery according to claim 5, characterized in that: The mass percentage content of the polybenzimidazole is in the range of 8wt%-16wt%; The molecular weight of the polybenzimidazole is in the range of 60,000 to 220,000; The inorganic particle size range is 10 nanometers to 50 nanometers; The mass percentage content of the inorganic substance is in the range of 0.5wt%-5wt%; The mass percentage content of the dispersant is in the range of 0.2wt%-0.3wt%; In step S1, the mixing temperature range is configured to be 60-90 degrees Celsius; The temperature range of the solution for phase inversion in step S3 is 5-50 degrees Celsius.

7. The method for preparing a proton membrane for a flow battery according to claim 6, characterized in that: The flat carrier includes a flat glass, a metal plate, a polymer plate, or a ceramic plate with a flat and smooth surface; The thickness of the thin layer of casting liquid is in the range of 100-600 microns.

8. The method for preparing a proton membrane for a flow battery according to claim 7, characterized in that: The phase inversion solution is one of saturated solutions of potassium chloride, sodium chloride and sodium hydroxide.

9. The method for preparing a proton membrane for a flow battery according to claim 8, characterized in that: The mass percentage content of the polybenzimidazole is 12wt%; The molecular weight range of the polybenzimidazole is 150,000; The inorganic particle size is 12 nanometers; The mass percentage content of the inorganic substance is 2wt%; The mass percentage content of the dispersant is 0.25wt%; In step S1, the mixing temperature range is configured to be 80 degrees Celsius; The temperature of the solution for phase inversion in step S3 is 10 degrees Celsius; The thickness of the thin layer of casting liquid is in the range of 400 microns.

10. A proton membrane for a liquid flow battery, characterized in that: The proton membrane of a liquid flow battery is prepared by the method for preparing the proton membrane of a liquid flow battery according to any one of claims 1 to 9.

Images