Semi-solid gel type electrolyte composite diaphragm as well as preparation method and application thereof

Abstract

The invention discloses a semi-solid gel type electrolyte composite diaphragm as well as a preparation method and application thereof, and belongs to the technical field of alkaline electrolytic cell ion exchange membranes. The composite diaphragm adopts a five-layer structural design and comprises an alkali-resistant base membrane, a porous sponge structure layer and a semi-solid gel layer, wherein the porous sponge structure layer and the semi-solid gel layer are symmetrical on the two sides; the preparation method comprises the following steps: firstly, introducing a polymer precursor, a hydroxyl conduction enhancer and a cross-linking agent into an alkaline aqueous solution to form a semi-solid network gel precursor solution, coating two sides of an alkali-resistant base membrane with the semi-solid network gel precursor solution, adding a porous sponge structure layer inside the semi-solid network gel precursor solution and the alkali-resistant base membrane, and then treating the whole original composite membrane by adopting chemical cross-linking and thermocuring to obtain the composite membrane. The preparation method comprises the following steps: adding a semi-solid gel layer into an alkali-resistant base membrane, tightly combining the semi-solid gel layer with a porous sponge structure layer and the alkali-resistant base membrane, finally, integrally soaking an original composite membrane into an alkaline electrolyte for ion activation, and completely drying after cleaning, thereby obtaining the semi-solid gel type electrolyte composite membrane with high safety, good structural stability and excellent ion conduction performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ion exchange membranes of alkaline electrolyzers, and particularly relates to a semi-solid gel type electrolyte composite diaphragm as well as a preparation method and application thereof. BACKGROUND

[0002] Alkaline electrolyzers are currently the most mature hydrogen production electrolyzers, and have achieved extensive commercial use. An alkaline water electrolyzer is mainly composed of an electrode and a diaphragm, and is divided into an anode chamber and a cathode chamber in the electrolyzer. Hydrogen and oxygen generated need to be separated by a diaphragm to prevent explosion caused by mixing of hydrogen and oxygen, so the diaphragm is a key component for safe operation of the electrolyzer, and also affects the purity of the prepared gas and the energy consumption of the electrolyzer.

[0003] The diaphragm suitable for the alkaline water electrolyzer should meet the following requirements: (1) ensuring that H2 and O2 molecules cannot permeate the diaphragm, but allowing electrolyte ions to permeate; (2) being able to resist corrosion of high-concentration alkali liquor; (3) having good mechanical strength, being able to withstand the impact of electrolyte and generated gas for a long time, and the diaphragm structure not being damaged; (4) in order to reduce energy loss, the diaphragm must have a small surface resistance, so the diaphragm porosity should be as high as possible; (5) the diaphragm can maintain chemical stability under electrolysis temperature and pH conditions.

[0004] Polymer diaphragms have good electrical conductivity, strong chemical stability, superior mechanical properties and other advantages, and are very promising alkaline water electrolysis diaphragm materials, but polymer diaphragms generally have poor hydrophilicity, high electrical resistance and poor gas barrier properties, resulting in high energy consumption and low safety. For example, polyphenylene sulfide (PPS) is a key component of the commercial alkaline electrolyzer diaphragm Zirfon. Due to the presence of benzene rings and sulfide bonds in its molecular structure, PPS has a certain flexibility, good thermal stability, corrosion resistance, mechanical properties and chemical stability in high-temperature environments, and is a very promising polymer diaphragm material. However, PPS fabric has poor hydrophilicity, resulting in large electrical resistance of the diaphragm and low electrolysis efficiency of the electrolyzer.

[0005] The third-generation alkaline electrolyzer composite diaphragm is a composite diaphragm with a sandwich structure formed by coating a composite slurry of inorganic matter and polymer on a PPS mesh. The inorganic matter is mainly zirconium oxide or other similar performance nanoparticles, and the oxygen ions in zirconium oxide form hydrogen bonds with water in the electrolyte, which is the main substance for improving the hydrophilicity of the composite diaphragm; the polymer can be poly sulfone, poly ether sulfone, PTFE, PPEK and other materials, and its main function is to bond zirconium oxide nanoparticles into a film.

[0006] Due to the high proportion of third-generation composite diaphragm nano-zirconium oxide particle components, the cost of the diaphragm is much higher than that of PPS woven fabric. In addition, the high proportion of composite material powder, poor mechanical strength, difficult operation, and easy to break, leading to safety hazards. For example, the Chinese patent with the application date of December 28, 2022 and the publication number of CN115928145A discloses an improved organic-inorganic composite diaphragm for alkaline electrolytic water hydrogen production and its preparation method. Zirconium oxychloride is added to the slurry of the polymer, and an ultrafiltration membrane is first prepared, and then in-situ precipitation is used to deposit zirconium hydroxide in the ultrafiltration membrane. Although zirconium hydroxide particles are introduced in this way, the ultrafiltration micropores still exist, and the bubble point is not improved, and the gas barrier property is poor.

[0007] The Chinese patent with the application date of November 8, 2022 and the publication number of CN101372752A discloses a non-woven fabric made of polyphenylene sulfide fibers, which is then subjected to sulfonation treatment with 70-130℃, 90-98% concentrated sulfuric acid for 20-40min, and then treated with 30% potassium hydroxide, finally obtaining a high-temperature-resistant alkaline water electrolysis cell diaphragm. In this invention, although the high-porosity structure of the non-woven fabric makes the ions in the electrolyte move easily, thereby reducing the total resistance in the electrolysis cell, but due to the loose structure of the non-woven fabric, the porosity is large, and the high gas barrier effect cannot be achieved, resulting in low gas purity during actual machine operation. On the other hand, the liquid absorption rate of the non-woven fabric is relatively strong, and after strong acid treatment, a large amount of valuable water resources and chemical drugs need to be consumed during the cleaning process, the cleaning process is long and complex, the drying energy consumption is also high, and the process operation is complex and not suitable for industrial production.

[0008] In addition, the current process of preparing diaphragms through phase inversion is relatively complex, and the materials used in addition to

[0009] PPS, polysulfone and inorganic nanoparticles, etc. Effective materials also need to add pore-forming agents, and a large amount of water needs to be used in the phase inversion process, which will produce a large amount of wastewater, and the diaphragm prepared by phase inversion is easy to become brittle in dry state, with poor flexibility, usually needs to be kept in a humid state.

[0010] The traditional alkaline electrolytic cell uses liquid alkaline electrolyte, which has the problems of liquid leakage, corrosion, gas cross and safety risk. The conventional gel electrolyte can reduce leakage, but the ion conductivity and gas isolation capacity are insufficient, especially under the conditions of large current or long time operation, the performance attenuation is obvious. Under the conditions of high temperature or long time operation of the alkaline electrolytic cell, the stability of the existing diaphragm combined with the electrolyte is insufficient, which can easily lead to performance attenuation. In addition, the mechanical strength and thermal stability of the existing diaphragm in the high concentration alkali environment are limited, and it is difficult to balance ion conduction, gas isolation and long-term durability, so a semi-solid gel electrolyte composite diaphragm is needed, which can replace the alkaline liquid or gel electrolyte, enhance the conductivity of hydroxyl ions, and at the same time block the anode and cathode gases, improve the safety and stability of the alkaline electrolytic cell.

[0011] At present, the application of gel electrolyte composite diaphragm in lithium and zinc ion batteries is very wide, but its function mainly aims at the problems of dendrite growth, hydrogen evolution side reaction, ion conductivity and safety of solid electrolyte, which is single and cannot be directly applied to electrolytic reaction, especially in semi-solid alkaline electrolytic cell. Therefore, a composite diaphragm for semi-solid alkaline electrolytic cell is studied, which has mechanical strength and ion conduction, improves the electrolyte retention and interface wettability, enhances the gas isolation and structural stability, and can avoid the safety hazards caused by liquid leakage of liquid alkaline electrolyte, which has important reference value and practical significance for promoting the development of semi-solid electrolysis technology and the industrial application of composite diaphragm. SUMMARY

[0012] In order to solve the problems in the prior art, the present application provides a semi-solid gel electrolyte composite diaphragm, a preparation method and application thereof, which has high safety, good structural stability and excellent ion conduction performance, and has a broad industrial application prospect in semi-solid alkaline electrolytic cell.

[0013] The technical scheme of the present application is as follows:

[0014] One of the purposes of the present application is to provide a preparation method of a semi-solid gel electrolyte composite diaphragm, which comprises the following steps:

[0015] S1, introducing polymer precursor, hydroxyl ion conduction enhancer and crosslinking agent into alkaline aqueous solution, stirring uniformly to form a semi-solid network gel precursor solution;

[0016] S2, increasing the porous sponge structure layer on both sides of the alkali-resistant base film by vacuum hot pressing composite method;

[0017] S3, coating semi-solid network gel precursor liquid on the outside of the alkali-resistant base film and the porous sponge structure layer, making the gel penetrate into the three-dimensional network formed by the porous sponge structure layer through capillary action and pore connectivity, and drying to form a uniform and dense semi-solid gel electrolyte layer, thereby obtaining a raw composite separator;

[0018] S4, treating the whole raw composite separator by chemical cross-linking combined with heat curing;

[0019] S5, soaking the whole raw composite separator in an alkaline electrolyte for ion activation, cleaning the surface after completion, and obtaining a semi-solid gel electrolyte composite separator after complete drying.

[0020] Further, the polymer precursor in S1 is any one of acrylate, polyvinylidene fluoride-hexafluoropropylene copolymer PVDF-HFP, and hydroxyl-modified polyacrylonitrile H-PAN; the polymer precursor is added to the alkaline aqueous solution at a mass ratio of 10-30%.

[0021] Further, the alkaline aqueous solution in S1 is a NaOH solution or a KOH solution with a pH value of 11-13.

[0022] Further, the hydroxyl ion conduction enhancer in S1 is any one of zinc oxide, hydroxyl-modified graphene, or hydroxide nanoparticles; the cross-linking agent is glutaraldehyde, glutaric acid diglycidyl ester

[0023] GAE or any one of epichlorohydrin EPI, which is added in an amount of 1-5% of the total solution.

[0024] Further, the alkali-resistant base film in S2 is any one of a polyolefin film, a polyimide film, or a cellulose-based film.

[0025] The porous sponge structure layer material mainly uses a white or translucent ePTFE microporous film as the main body, the contact angle of which is 70-90°, the pore size distribution is in the range of 50-500 nm, the porosity is 60-85%, and the specific surface area is 5-50 m 2 / g;

[0026] The porous sponge structure layer presents a flexible solid film morphology, and the thickness is 20-100 μm, and the compression resilience is ≥85%.

[0027] Further, the process in S2 is as follows: first, the interface affinity of the alkali-resistant base film is enhanced by plasma activation, and then the porous sponge structure layer is cut into a sheet material matching the size of the alkali-resistant base film, which is covered on one side of the alkali-resistant base film, and is hot-pressed at 80-120℃, 0.2-0.5 MPa for 3-5 min.

[0028] Further, the S3 is dried at 60-80 DEG C to form a semi-solid gel electrolyte layer.

[0029] Further, the S4 is chemically cross-linked and heat cured as follows: the original composite separator is reacted as a whole at 40-60 DEG C for 1-2 hours, and after the chemical reaction between polymer chains forms a stable three-dimensional network structure, the composite separator is taken out and heat cured at 100 DEG C for 60 minutes.

[0030] Further, the S5 is ion-activated by soaking the original composite separator in an alkaline electrolyte with a concentration of 3-10 M for 12 hours; after ion activation, the surface of the original composite separator is cleaned with deionized water, and dried at 50-60 DEG C for 12 hours to obtain a semi-solid gel electrolyte composite separator.

[0031] The second object of the present application is to provide a semi-solid gel electrolyte composite separator.

[0032] Further, the semi-solid gel electrolyte composite separator has a five-layer composite structure, including an alkali-resistant base film in the middle, and porous sponge structure layers and semi-solid gel layers symmetrically distributed on both sides.

[0033] The third object of the present application is to provide an application of the semi-solid gel electrolyte composite separator in the preparation of a semi-solid alkaline electrolytic cell.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] 1. The present application is directed to an alkaline semi-solid electrolytic cell system, and a novel semi-solid gel electrolyte composite separator is innovated, which can replace liquid alkaline electrolyte or gel-type alkaline electrolyte, and has excellent gas isolation and electrolysis effect, and also has excellent mechanical strength, thermal stability, and dimensional stability in a concentrated alkali environment.

[0036] 2、The porous sponge structure layer in the composite diaphragm of the application acts as a flexible buffer layer, effectively absorbing and dispersing internal and external mechanical stress, preventing the interface between the alkali-resistant base film and the gel layer from peeling off or breaking under stress, and at the same time, its specific surface area and pores can adsorb and store a large amount of liquid electrolyte, providing a continuous ion transmission channel to continuously supply the adjacent semi-solid gel layer, ensuring that the gel layer is in the best state of ion conduction with sufficient swelling, avoiding performance degradation due to electrolyte loss, and together realizing ideal and stable ionic conductivity. The semi-solid gel layer uses the alkali-resistant base film as a support plane, and fills the gel through its stable three-dimensional network structure to realize ion transmission and gas barrier, preventing cracks and other defects in the gel electrolyte layer due to swelling or shrinkage. The porous sponge structure layer eliminates the gap between the layers and avoids the possibility of gas penetrating along the interface, effectively blocking the penetration of hydrogen and oxygen molecules, and preventing the mixing of gases at both poles.

[0037] 3、The semi-solid gel-type electrolyte composite diaphragm of the application can directly replace the liquid electrolyte or the gel electrolyte with insufficient performance in the existing alkaline electrolytic cell, thereby fundamentally eliminating the risk of liquid leakage and improving the safety and reliability of the equipment. During operation, the composite diaphragm can effectively suppress the bubble effect and ensure stable electrolysis, thereby improving the electrolysis efficiency and service life. Compared to traditional gel diaphragms mainly for secondary batteries, the semi-solid gel-type electrolyte composite diaphragm is suitable for the emerging field of semi-solid alkaline electrolytic cells, showing good application specificity. Its preparation process is simple and controllable, all raw materials are widely available, low in cost and environmentally friendly, and has the potential for large-scale production, which is of great significance for promoting the industrialization development of high-performance and high-safety alkaline electrolytic cells. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The semi-solid gel-type electrolyte composite diaphragm of the application is shown in the structural diagram;

[0039] 1-1, base film; 1-2, sponge / porous structure layer; 1-3, gel layer;

[0040] Figure 2 The semi-solid gel-type electrolyte composite diaphragm of the application is shown in the structural diagram;

[0041] 2-1, support plate; 2-2, conductive metal plate; 2-3, anode plate; 2-4, prepared semi-solid gel-type electrolyte composite diaphragm; 2-5, cathode plate; 2-1-1, bolt hole; 2-1-2, water inlet; 2-1-3, gas outlet; 2-2-1, bolt hole; 2-2-2, water inlet; 2-2-3, gas outlet. DETAILED DESCRIPTION

[0042] The following further describes the present application in connection with preferred embodiments, and the endpoints of the ranges and any values disclosed herein are intended to be the abutment of said range or value, and that these ranges or values are understood to be inclusive of values proximate thereto; and that the endpoints of the ranges of values can be combined with the endpoints of other ranges or values to create new ranges of values, which are to be considered disclosed herein.

[0043] The experimental methods in the following examples are all conventional methods, and are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions, unless otherwise specified.

[0044] The materials, reagents, etc. used in the following examples can be obtained commercially, unless otherwise specified.

[0045] Example 1

[0046] The present embodiment provides a preparation method of a semi-solid gel-type electrolyte composite separator, comprising the following steps:

[0047] S1, introducing methyl acrylate at a mass ratio of 20% and a crosslinking agent glutaraldehyde at a total solution mass fraction of 3% into a NaOH solution with a pH value of 12, adding a hydroxyl ion conduction enhancer zinc oxide and stirring uniformly to form a semi-solid network gel precursor solution;

[0048] S2, forming a white ePTFE microporous membrane with a contact angle of 80°, a pore size distribution in the range of 350 nm, a porosity of 72%, and a specific surface area of 30 m 2 / g, cutting the white ePTFE microporous membrane into a sheet material matching the size of the polyolefin membrane, covering both sides of the polyolefin membrane, hot pressing at 100°C and 0. MPa for 4 min to form a porous sponge structure layer with a thickness of 60 μm;

[0049] S3, coating the semi-solid network gel precursor solution on both outer sides of the polyolefin membrane and the porous sponge structure layer, drying at 70°C to form a uniform and dense semi-solid gel electrolyte layer, and obtaining a raw composite separator;

[0050] S4, reacting the raw composite separator as a whole at 50°C for 1.5 h, and after the chemical reaction between the polymer chains forms a stable three-dimensional network structure, taking out the composite separator and heat curing at 100°C for 60 min;

[0051] S5, immersing the raw composite separator as a whole in an alkaline electrolyte with a concentration of 6M for 12 h for ion activation, washing the surface with deionized water after completion, and drying completely at 55°C for 12 h to obtain a semi-solid gel-type electrolyte composite separator.

[0052] Example 2

[0053] The embodiment provides a preparation method of a semi-solid gel type electrolyte composite diaphragm, and the method comprises the following steps:

[0054] S1, introducing polyvinylidene fluoride-hexafluoropropylene copolymer PVDF-HFP in a KOH solution with a pH value of 11 at a mass ratio of 10%, and adding a crosslinking agent glycol diglycidyl glutarate with a total solution mass fraction of 1%

[0055] GAE, adding a hydroxyl modified graphene hydroxide conductive enhancer and stirring uniformly to form a semi-solid network gel precursor solution;

[0056] S2, the contact angle is 70°, the pore size distribution is in the range of 50 nm, the porosity is 60%, and the specific surface area is 5 m 2 / g, and the semi-transparent ePTFE microporous membrane is used as raw material, which is cut into a piece matching the size of the polyimide film, and is covered on both sides of the polyimide film, and is hot-pressed at 80 DEG C and 0.5 MPa for 5 min to form a porous sponge structure layer with a thickness of 20 μm;

[0057] S3, the semi-solid network gel precursor solution is coated on the outer sides of the polyimide film and the porous sponge structure layer, and is dried at 60 DEG C to form a uniform and dense semi-solid gel electrolyte layer, and an original composite diaphragm is prepared;

[0058] S4, the original composite diaphragm is reacted as a whole at 40 DEG C for 2 h, and after the chemical reaction between the polymer chains forms a stable three-dimensional network structure, the composite diaphragm is taken out and is heat-cured at 100 DEG C for 60 min;

[0059] S5, the original composite diaphragm is soaked in a 3M alkaline electrolyte for 12 h for ion activation, after completion, the surface is washed with deionized water, and is completely dried at 50 DEG C for 12 h to obtain a semi-solid gel type electrolyte composite diaphragm.

[0060] Embodiment 3

[0061] The embodiment provides a semi-solid gel type electrolyte composite diaphragm, and a preparation method thereof comprises the following steps:

[0062] S1, introducing hydroxyl modified polyacrylonitrile H-PAN in a NaOH solution with a pH value of 13 at a mass ratio of 30%, and adding a crosslinking agent epoxy chloropropane EPI with a total solution mass fraction of 5%, and adding magnesium hydroxide Mg(OH)2 nanoparticles as a hydroxyl conductive enhancer and stirring uniformly to form a semi-solid network gel precursor solution;

[0063] S2, the contact angle is 90°, the pore size distribution is in the range of 500 nm, the porosity is 85%, and the specific surface area is 50 m 2 / g, the white ePTFE microporous membrane is used as raw material, cut into a piece matching the size of the cellulose-based membrane, covered on both sides of the cellulose-based membrane, hot-pressed at 120°C and 0.2 MPa for 3 min to form a porous sponge structure layer with a thickness of 100 μm;

[0064] S3, coating a semi-solid network gel precursor on both outer sides of the cellulose-based membrane and the porous sponge structure layer, drying at 80°C to form a uniform and dense semi-solid gel electrolyte layer, to obtain a raw composite separator;

[0065] S4, reacting the whole raw composite separator at 60°C for 1 h, after the chemical reaction between polymer chains forms a stable three-dimensional network structure, taking out the composite separator and heat curing at 100°C for 60 min;

[0066] S5, soaking the whole raw composite separator in a 10M alkaline electrolyte for 12 h for ion activation, after completion, washing the surface with deionized water and drying completely at 60°C for 12 h, to obtain a semi-solid gel electrolyte composite separator.

[0067] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a semi-solid gel-type electrolyte composite membrane, characterized in that, Includes the following steps: S1. Introduce the polymer precursor, hydroxide conduction enhancer and crosslinking agent into an alkaline aqueous solution, stir evenly to form a semi-solid network gel precursor solution. S2. A porous sponge structure layer is added to both sides of the alkali-resistant base film by vacuum hot pressing composite method; S3. A semi-solid network gel precursor liquid is coated on the outside of both the alkali-resistant membrane and the porous sponge structure layer. Through capillary action and pore connectivity, the gel penetrates into the three-dimensional network formed by the porous sponge structure layer. After drying, a uniform and dense semi-solid gel electrolyte layer is formed, thus obtaining the original composite membrane. S4. The original composite membrane is treated with a combination of chemical cross-linking and thermosetting methods. S5. The original composite membrane is immersed in an alkaline electrolyte for ion activation. After the activation is completed, its surface is cleaned and completely dried to obtain a semi-solid gel electrolyte composite membrane.

2. The method for preparing a semi-solid gel-type electrolyte composite membrane according to claim 1, characterized in that, The polymer precursor in S1 is any one of acrylates, polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), or hydroxyl-modified polyacrylonitrile (H-PAN); the polymer precursor is added to an alkaline aqueous solution at a mass ratio of 10-30%.

3. The method for preparing a semi-solid gel-type electrolyte composite membrane according to claim 1, characterized in that, The alkaline aqueous solution in S1 is a NaOH solution or KOH solution with a pH value of 11 to 13.

4. The method for preparing a semi-solid gel-type electrolyte composite membrane according to claim 1, characterized in that, The hydroxide conduction enhancer in S1 is any one of zinc oxide, hydroxyl-modified graphene, or hydroxide nanoparticles; the crosslinking agent is any one of glutaraldehyde, diglycidyl glutarate (GAE), or epichlorohydrin (EPI), and its addition amount is 1-5% of the total solution mass fraction.

5. The method for preparing a semi-solid gel-type electrolyte composite membrane according to claim 1, characterized in that, The alkali-resistant membrane in S2 is any one of polyolefin membrane, polyimide membrane, or cellulose-based membrane. The porous sponge structure layer material is mainly composed of a white or semi-transparent ePTFE microporous membrane with a contact angle of 70° to 90°, a pore size distribution in the range of 50 nm to 500 nm, a porosity of 60% to 85%, and a specific surface area of ​​5 to 50 m². 2 / g; The porous sponge structure layer exhibits a flexible solid film morphology with a thickness of 20–100 μm and a compression resilience of ≥85%.

6. The method for preparing a semi-solid gel-type electrolyte composite membrane according to claim 1, characterized in that, The process added in S2 is as follows: First, the interfacial affinity of the alkali-resistant membrane is enhanced by plasma activation. Then, the porous sponge structure layer is cut into a sheet that matches the size of the alkali-resistant membrane and covered on one side of the alkali-resistant membrane. It is then hot-pressed at 80-120°C and 0.2-0.5MPa for 3-5 minutes.

7. The method for preparing a semi-solid gel-type electrolyte composite membrane according to claim 1, characterized in that, The steps of the chemical cross-linking combined with thermosetting method in S4 are as follows: the original composite membrane is reacted as a whole at 40-60℃ for 1-2 hours. After the polymer chains undergo chemical reaction to form a stable three-dimensional network structure, the composite membrane is taken out and thermoset at 100℃ for 60 minutes.

8. The method for preparing a semi-solid gel-type electrolyte composite membrane according to claim 1, characterized in that, In step S5, the original composite membrane is immersed in an alkaline electrolyte solution with a concentration of 3-10M for 12 hours to complete ion activation. After ion activation, the surface of the original composite membrane is washed with deionized water and completely dried at 50-60℃ for 12 hours to obtain a semi-solid gel-type electrolyte composite membrane.

9. A high-permeability carbon molecular sieve gas separation membrane prepared by the method according to any one of claims 1 to 8, characterized in that, The semi-solid gel electrolyte composite membrane has a five-layer composite structure, including an alkali-resistant membrane in the middle, and porous sponge structure layers and semi-solid gel layers symmetrically distributed on both sides.

10. The application of a high-permeability carbon molecular sieve gas separation membrane prepared by any one of claims 1 to 8 in the preparation of a semi-solid alkaline electrolyzer.

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