Enhanced anion exchange membrane based on microporous skeleton and integrated membrane electrode

Abstract

The invention discloses an enhanced anion exchange membrane based on a microporous skeleton and an integrated membrane electrode. The enhanced anion exchange membrane comprises a microporous skeleton layer and an anion exchange layer laminated on one side surface of the microporous skeleton layer, the anion exchange layer comprises an anion conductor material; the anion conductor material fills part of holes of the microporous framework layer so as to form an anion exchange area on one side close to the anion exchange layer; in the anion exchange region, the anion conductor material forms a gradually decreasing concentration gradient inward from a side near the anion exchange layer. According to the invention, based on the durable microporous skeleton reinforcing layer, the high-performance, stable and durable enhanced anion exchange membrane and the integrated membrane electrode are prepared through a gradient filling technology and structural optimization design; the technical problems urgently needing to be solved in the fields of fuel cells and hydrogen production by electrolysis of water, such as contradiction between mechanical strength and ionic conductivity of a membrane material, high contact resistance of a catalyst interface and easiness in falling off, are solved.

Description

Technical Field

[0001] The invention relates to the field of new energy technology, in particular to the field of ion exchange membrane material manufacturing in fuel cells and water electrolysis hydrogen production devices, and more particularly to an enhanced anion exchange membrane and integrated membrane electrode based on a microporous skeleton, as well as their preparation methods. Background Art

[0002] Hydrogen is a clean, renewable energy source with outstanding advantages such as high energy density and zero pollution. Its use and development is one of the most viable approaches to addressing energy and environmental challenges. Currently, mainstream hydrogen production routes include chemical hydrogen production from fossil fuels, biomass hydrogen production, and water electrolysis. Only hydrogen produced by electrolysis of water using green electricity, such as wind and photovoltaic power, is considered green. Wind and photovoltaic power output is unstable, and peak power often cannot be fully absorbed by the grid, leading to curtailment. Electrochemical hydrogen production technology is well-suited to wind and photovoltaic power. Combining water electrolysis with green electricity has recently become a key approach for large-scale, integrated development and utilization of renewable energy. Green hydrogen is not only an energy source but also a basic chemical raw material. Converting green electricity into green hydrogen (P2G) using a water electrolysis hydrogen production device (electrolyzer) not only enables large-scale, long-term energy storage of green electricity but also drives the development of green chemicals, a significant market opportunity. There are four main types of electrolyzers: ALKWE, PEMWE, AEMWE, and SOEC. ALKWE is a mature technology that operates under strong alkaline, low-pressure conditions and offers low manufacturing costs, but it suffers from low electrolysis efficiency, poor power responsiveness, and high O&M costs. PEMWE operates under acidic, high-pressure conditions, offering high current density, high electrolysis efficiency, and fast power response. However, it relies on platinum group precious metal (PGM) catalysts, resulting in high costs and limited large-scale adoption due to the availability of PGMs. The AEMWE electrolyzer, similar to the ALKWE electrolyzer in its use of a weakly alkaline electrolyte and non-platinum catalysts, offers low cost. Like the PEMWE electrolyzer, it also utilizes a polymer electrolyte membrane structure with a zero-gap membrane electrode configuration. This makes it, like the PEMWE, compact, maintenance-free, and fast power response. Furthermore, it offers higher electrolysis efficiency than the PEMWE. It is currently a hot research and development area for water electrolysis hydrogen production devices and is considered a key direction for future electrolyzer development. Although SOEC has a higher electrolysis efficiency than AEMWE, it must work at high temperatures, has high material costs, and has few application scenarios, making it difficult to enter commercial applications.

[0003] The main technical difficulties currently facing AEMWE technology are: 1. The chemical stability of the fixed quaternary ammonium cations in the anion exchange membrane (AEM) is high, leading to easy decomposition and elimination, resulting in a short operating life of the AEM membrane; 2. Compared with the proton exchange membrane (PEM), the high ion exchange capacity (IEC) leads to a high water absorption and swelling rate, resulting in poor dimensional stability and low wet membrane strength. These two issues seriously affect the operating stability and electrochemical performance of AEMWE.

[0004] To address the issues caused by high swelling rates, non-woven fabrics, woven meshes, or porous films are currently commonly used as reinforcement layers for anion exchange membranes. This built-in reinforcement layer is typically made of a hydrophobic material that does not swell in aqueous solution, thus maintaining its strength in the dry state. Furthermore, it spatially separates the AEM, distributing the swelling stress of the AEM after water absorption, preventing the membrane from severely flexing and losing its flatness due to uneven swelling stress after water absorption. However, the reinforcement layer occupies a certain amount of space, reducing ion transport channels and increasing membrane resistance. Furthermore, for thin films with microporous reinforcement layers, a simple surface coating process with an AEM solution cannot completely fill the micropores of the reinforcement layer, further reducing the ionic conductivity of the composite membrane and causing the AEM to fall off due to a weak bond between the reinforcement layer and the membrane. Therefore, when using porous membranes to prepare reinforced AEM membranes, wetting between the AEM solution and the porous membrane must be addressed.

[0005] Invention CN119529349A discloses a porous substrate reinforced anion exchange membrane, which is obtained by mixing a polyarylene alkylene type cationic polymer solution with a C1-C10 alcohol solvent, coating it on both sides of the porous substrate, and removing the solvent. The invention does not require pretreatment of the porous substrate to achieve good infiltration of the cationic polymer solution into the porous substrate, thereby obtaining a porous substrate reinforced anion exchange membrane with a sandwich-like structure. Although the membrane has outstanding anti-swelling properties, excellent mechanical properties, and good electrochemical properties, this method of coating both sides of the porous reinforcing layer with an AEM solution has weak adhesion between the catalyst and the AEM when the catalyst layer is applied. During the subsequent use of the membrane electrode, the catalyst is easily detached due to gas-liquid erosion, causing premature degradation of the electrode performance. To address this issue, invention CN119506921A discloses a structural design for an AEM electrolyzer, which is equipped with a cathode catalytic substrate and an anode catalytic substrate, providing a certain surface pressure for the cathode catalytic layer and the anode catalytic layer, respectively, so that the catalytic layers are evenly adhered to both sides of the enhanced anion exchange membrane. However, the membrane electrode structure is relatively complex, increasing the occupied space and manufacturing costs, and the flat bonding cannot ensure the stable bonding of the rough catalyst area with the AEM membrane.

[0006] As a reinforcement layer, porous films offer significant advantages in tensile strength over nonwovens and woven meshes. Designing and fabricating high-performance, stable, and durable reinforced anion exchange membranes and membrane electrodes based on a microporous skeleton reinforcement layer that is resistant to alkaline water swelling, while addressing the conflict between low-wet tensile strength, large swelling deflection, and high ionic conductivity of AEM membranes, while simultaneously addressing issues such as high catalyst / AEM interface contact resistance and catalyst detachment, are pressing technical challenges in the development of fuel cells and electrolyzers for hydrogen production from water electrolysis. Summary of the Invention

[0007] In response to the defects in the above-mentioned prior art, the present invention provides an enhanced anion exchange membrane based on a microporous skeleton and a preparation method thereof, an integrated membrane electrode and a preparation method thereof. Through gradient filling technology and structural optimization, the problems in the prior art such as the contradiction between the mechanical strength and ion conductivity of the membrane material, the high contact resistance of the catalyst / AEM interface, and the easy detachment of the catalyst are solved.

[0008] In a first aspect, the present invention provides an enhanced anion exchange membrane based on a microporous skeleton, comprising a microporous skeleton layer, and an anion exchange layer laminated on one side of the microporous skeleton layer; The anion exchange layer includes an anion conductor material; The anion conductor material fills part of the pores of the microporous skeleton layer to form an anion exchange region on the side close to the anion exchange layer; In the anion exchange region, the anion conductor material forms a decreasing concentration gradient from the side close to the anion exchange layer toward the inside.

[0009] The present invention forms a concentration gradient along the thickness of the microporous skeleton layer by repeatedly permeating the anion conductor resin casting solution. This allows the anion conductor resin material to be gradually accumulated on the coating surface and in the internal micropores, thereby increasing the number of ion transport channels and the conductivity of the ion exchange membrane. Furthermore, due to the formation of a gradually decreasing concentration gradient, the anion conductor polymer is almost absent or present only in small quantities on the other side of the microporous skeleton layer away from the anion exchange layer, providing microporous anchoring points for the deposition of other materials in subsequent applications.

[0010] Furthermore, the microporous skeleton layer includes at least one of a polyethylene film, a polypropylene film, a polyamide film, and a polytetrafluoroethylene film; The thickness of the microporous skeleton layer is 5-60 μm, the porosity is 40-80%, and the pore size is 0.05-2 μm.

[0011] Furthermore, the microporous skeleton layer is subjected to a hydrophilic modification treatment, comprising the following steps: preparing a hydrophilic modification solution, wherein the hydrophilic modification solution comprises one or more of ethylene-vinyl alcohol copolymer and dopamine; The microporous skeleton is immersed in the hydrophilic modification solution and subjected to ultrasonic modification treatment.

[0012] Furthermore, the ultrasonic treatment is preferably carried out for 10-30 min, and the excess solution on the surface is removed and dried to obtain a surface hydrophilic microporous skeleton membrane.

[0013] Furthermore, the hydrophilic modification solution is obtained by dissolving one or more of ethylene-vinyl alcohol copolymer and dopamine in an alcohol-water solution at a total concentration of 0.5-2.5 g / L. The alcohol-water solution is obtained by mixing one or more of n-propanol, isopropanol, ethanol, and methanol with deionized water or the like in a certain proportion. The alcohol-water solution preferably has a volume ratio of (1-5):(5-9) of alcohol to water.

[0014] Furthermore, the anion conductor material comprises an aryl piperidine resin. Specifically, the anion conductor material is a resin material having anion exchange capacity formed by super acid catalytic polymerization of an aromatic polymer as the main chain and piperidine, imidazole, spirocycle, fatty ammonium, quaternary phosphine, guanidine salt, and metal cation as cationic functional groups.

[0015] The anionic conductor material described in this invention utilizes an aromatic piperidine resin as its core system. Its molecular structure consists of a rigid aromatic hydrocarbon backbone synergistically linked with piperidine, imidazole, or spirocyclic quaternary ammonium cation functional groups. This material is synthesized using metal-free superacid-catalyzed polymerization technology. Using a Brønsted superacid such as trifluoromethanesulfonic acid (TFSA) as a proton source, the material undergoes a Friedel-Crafts alkylation reaction in a room-temperature solution system to achieve the gradual polycondensation of aromatic hydrocarbon monomers, forming an "ether-bond-free" aromatic polymer network with both high alkali resistance and ion conductivity. During the reaction, the carbonyl group of the ketone-containing monomer is protonated in the superacid environment to form a highly reactive carbocation intermediate, which drives directional coupling with polycyclic aromatic hydrocarbons such as biphenyl and terphenyl, ultimately constructing a topologically controllable three-dimensional cross-linked structure. Commonly used monomers include two categories: ketone-containing monomers and aromatic hydrocarbons. Common aromatic hydrocarbons include biphenyl, terphenyls of different conformations, and p-quaterphenyl. Ketone-containing monomers include aldehydes, ketones, nitriles, fluorinated ketone monomers, and 1,2-dicarbonyl (hereinafter referred to as diketone monomers).

[0016] Furthermore, based on the total thickness L0 of the microporous skeleton layer, the thickness L1 of the anion exchange layer satisfies: 2%×L0≤L1≤20%×L0; From the side close to the anion exchange layer, the thickness L2 of the microporous skeleton layer filled with the anion conductor material satisfies: 20%×L0≤L2<100%×L0.

[0017] In a second aspect, the present invention provides a method for preparing an enhanced anion exchange membrane, comprising the following steps: Step 1: hydrophilic modification of the microporous skeleton layer; Step 2: preparing a casting solution C1 and a casting solution C2 containing an anion conductor material, wherein the concentration of the casting solution C1 is lower than that of the casting solution C2; Step 3: Apply the casting solution C1 to one side of the microporous skeleton layer, and repeat the application several times after drying, so that the anion conductor material fills part of the pores of the microporous skeleton layer; Step 4: applying the casting solution C2 to the side surface and vacuum drying to obtain an anion exchange layer laminated on one side surface of the microporous skeleton layer and an anion exchange region close to the anion exchange layer.

[0018] The anion exchange region of the present invention forms a decreasing concentration gradient of the anion conductor material along its thickness. Due to differences in infiltration travel and resistance along the thickness, a certain concentration gradient can be formed after multiple applications of the casting solution. Furthermore, to controllably form the concentration gradient, the same concentration of casting solution can be repeatedly applied multiple times, with the resulting concentration gradient adjusted by varying the amount applied each time. Alternatively, the concentration gradient can be formed by adjusting the degree of infiltration of the casting solution at different drying rates. Alternatively, casting solutions of different concentrations can be applied sequentially to form a concentration gradient with a controllable gradient change. Alternatively, vacuum-assisted infiltration filling can be used to guide the formation of concentration gradients in different regions.

[0019] The casting solution is obtained by dissolving an anion conductor material in a desired mass fraction in one or more of the polar solvents dimethyl sulfoxide, N-methylpyrrolidone, and N,N-dimethylimide, and mixing them uniformly. Generally speaking, the mass concentrations of casting solution C1 and casting solution C2 are between 10-30wt%, and the concentration of casting solution C1 is lower than that of casting solution C2. For example, the concentration of casting solution C1 is controlled at 10-25wt%, and the concentration of casting solution C2 is controlled at 20-30wt%. Low-concentration casting solution C1 is repeatedly applied to one side of the microporous skeleton layer and dried, so that the anion conductor material in casting solution C1 gradually fills the pores of the microporous skeleton layer. After repeated stacking and filling, the pores on the side closest to the anion exchange layer gradually become completely filled, and a gradually decreasing concentration gradient is formed from this side inward.

[0020] Furthermore, in step 2, the casting solution C1 is configured to include casting solutions C with increasing concentrations. 1-1 , casting liquid C 1-2 , ... and casting solution C 1-n , n is a natural number greater than 1; In step 3, the casting solution C 1-1 , casting liquid C 1-2 , ... and casting solution C 1-n The anion conductor materials are applied and dried sequentially, so that the anion conductor materials fill part of the pores of the microporous skeleton layer and form a decreasing concentration gradient from the outside to the inside.

[0021] For example, the casting solution C1 can be divided into three casting solutions with increasing concentrations (i.e., n is 3 for example), and applied in the order from low concentration to high concentration, wherein the casting solution C 1-1 The concentration of the casting solution C can be selected from 10-15wt%. 1-2 The concentration of the casting solution C can be selected from 15-20wt%. 1-3 The concentration can be selected from 20-25wt%.

[0022] More preferably, 1. casting solution C 1-1 The concentration of the casting solution C can be 10wt% 1-2 The concentration of the casting solution C can be 15wt% 1-3 The concentration can be selected as 20wt%.

[0023] The low-concentration casting solution is able to quickly fill a group of holes at a long distance due to its good fluidity, large number of skeleton voids, and low filling difficulty. When the high-concentration casting solution is filled later, due to the influence of fluidity and steric hindrance, at the same filling time, its farthest end will not be able to reach the holes reached by the previous low-concentration casting solution. Therefore, the above-mentioned filling method can be used to simply and quickly form a gradually decreasing concentration gradient in the microporous skeleton layer. The selection of the above-mentioned concentration range is also based on the thickness, porosity and pore size of the microporous skeleton layer, as well as the viscosity of the casting solution. When the concentration of the casting solution is too low, the casting solution will penetrate the microporous skeleton layer in large quantities, making it difficult to leave unfilled holes on the other side. When the concentration of the casting solution is too high, it is difficult to effectively penetrate and fill the holes in the microporous skeleton, resulting in a decrease in the amount of ion transmission channels and electrical conductivity.

[0024] In a third aspect, the present invention provides an integrated membrane electrode based on the enhanced anion exchange membrane, which sequentially comprises an anode catalyst layer, an enhanced anion exchange membrane and a cathode catalyst layer; The anode catalyst layer is connected to the anion exchange layer; The cathode catalyst layer is connected to the other side of the microporous skeleton layer away from the anion exchange layer; The pores of the microporous skeleton layer on the side close to the cathode catalyst layer are at least partially filled with cathode catalyst to form a cathode catalyst region.

[0025] Furthermore, the integrated membrane electrode satisfies at least one of the following characteristics: 1) The anode catalyst layer includes a layered double hydroxide (LDH) catalyst with a loading of 2-20 mg / cm 2 , preferably 5-18 mg / cm 2 , more preferably 8-15 mg / cm 2 ; 2) The cathode catalyst layer includes a Pt / C catalyst with a loading of 0.2-1.0 mg / cm 2 , preferably 0.3-0.8 mg / cm 2 .

[0026] The present invention effectively utilizes the pores of the microporous skeleton layer to not only form an anion conductor material concentration gradient in the anion exchange region of the enhanced anion exchange membrane, but also forms a cathode catalytic region filled with a cathode catalyst in at least a portion of the remaining unfilled pores relative to the anion exchange region. The formation of the anion exchange region and the cathode catalytic region is particularly beneficial for the application of the integrated membrane electrode in fuel cells and water electrolysis hydrogen production: on the one hand, the pore filling rate in the microporous skeleton layer is significantly improved, and the microporous skeleton layer can provide more three-dimensional space to help the catalyst form a three-dimensional structure, thereby improving the catalytic efficiency and resolving the contradiction between the mechanical strength and ionic conductivity of the membrane material; on the other hand, the pores of the microporous skeleton layer provide reliable anchoring points for the long-term stable attachment of the layers laminated on both sides, especially the catalyst layer, and enhance the mechanical anchoring effect under the action of chemical adhesion, which can effectively reduce the risk of catalyst failure due to loss due to gas-liquid erosion during subsequent use, thereby resolving defects such as high catalyst interface contact resistance and easy shedding. Compared with the existing sandwich structure with a single AEM material reinforcement layer symmetrically filled on both sides, the present invention fully utilizes the three-dimensional pore network of the microporous skeleton layer to form a double-material filling structure with an embedded mechanical anchoring micromorphology. While improving the performance of ion transmission and other aspects, it also extends the service life of the ion exchange membrane, reduces material costs, and has great promotion value.

[0027] In a fourth aspect, the present invention further provides a method for preparing an integrated membrane electrode, comprising the following steps: S1: preparing the enhanced anion exchange membrane; S2: preparing anode catalyst slurry and cathode catalyst slurry; S3: applying the cathode catalyst slurry to the other side of the microporous skeleton layer away from the anion exchange layer, and filling part of the cathode catalyst into the pores of the microporous skeleton layer close to the cathode catalyst layer to form the cathode catalyst layer and the cathode catalyst region; S4: forming the anode catalyst layer on the anion exchange layer using an anode catalyst slurry.

[0028] Furthermore, a cathode catalyst slurry is prepared by mixing 30-60% Pt / C catalyst, ionomer, ethanol, and water in a mass ratio of 0.1-5:5-10:30-50:10-20. The cathode catalyst slurry is applied by a spraying process selected from ultrasonic spraying, electrostatic spraying, and manual spraying.

[0029] Furthermore, the anode catalyst is an iron-cobalt-nickel double hydroxide obtained by hydrothermal reaction of an iron-cobalt-nickel precursor. The anode catalyst slurry is prepared by mixing an LDH catalyst, a binder, a dispersant, and an organic solvent in a mass ratio of 20-50:5-15:5-8:40-60. The binder comprises a mixed solution containing 5-15wt% anionic ionomer and 2-6wt% polytetrafluoroethylene; the dispersant comprises a mixture of one or more of methanol, n-propanol, isopropanol, and ethanol; and the organic solvent comprises a mixture of one or more of N-methylpyrrolidone, N,N-dimethylimide, and dimethyl sulfoxide.

[0030] Furthermore, step S4 forms the anode catalyst layer by thermal transfer, including: (1) Coating the anode catalyst slurry on the release film and drying it to obtain the anode catalyst thermal transfer sheet; (2) Cover the anode catalyst thermal transfer sheet on the anion exchange layer of the enhanced anion exchange membrane; cover the cathode catalyst layer on the other side with a blank release film; (3) The anode catalyst layer is thermally transferred to the surface of the anion exchange layer of the enhanced anion exchange membrane on a hot press at a certain temperature and pressure, and finally an integrated membrane electrode with a "sandwich" structure with a cathode catalyst layer and an anode catalyst layer on both sides is obtained.

[0031] Furthermore, the anode catalyst slurry is applied to the release film by a slot coating process, with a coating thickness of 20-100 μm, and the release film is selected from a PTFE film or a PET film, with a thickness of 50-200 μm.

[0032] Furthermore, in step (3), the hot pressing temperature of the hot press is 60-120°C, the hot pressing pressure is 2-10 MPa, and the time is 1-3 hours.

[0033] The beneficial effects of the present invention include at least: (1) The present invention forms a concentration gradient along the thickness of the microporous skeleton layer by repeatedly infiltrating the anion conductor resin casting solution. This allows the anion conductor resin material to gradually accumulate on the coating surface and in the internal micropores, thereby increasing the amount of ion transport channels and the conductivity of the ion exchange membrane. Furthermore, the unfilled pore areas in the microporous skeleton layer provide three-dimensional filling space and microporous anchoring points for the subsequent cathode catalyst, which is conducive to the formation of a stable and highly active catalytic interface.

[0034] (2) The present invention utilizes the three-dimensional structure of the pores in the microporous skeleton layer and forms a double-material filling structure with an embedded mechanical anchoring micromorphology through anion conductor material and catalyst material, so that the mechanical strength, anti-swelling performance and ion conductivity of the integrated membrane electrode are significantly improved. The comprehensive performance exceeds the homogeneous membrane base material and single-material sandwich structure membrane in the existing technology.

[0035] (3) The adhesion and stability of the catalyst layer of the integrated membrane electrode of the present invention are significantly improved. By filling the three-dimensional pores of the microporous skeleton layer with cathode catalyst, a cathode catalytic region is formed that is integrated with the cathode catalyst layer. This fully utilizes the chemical interlayer bonding force and the insert-type mechanical anchoring force, thereby enhancing the bonding effect between the catalyst layer and the microporous skeleton layer and reducing the risk of catalyst shedding and loss due to gas-liquid erosion. While improving ion transport and other performance, it also extends the service life of the ion exchange membrane and reduces material costs, which has great promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of the integrated membrane electrode based on the enhanced anion exchange membrane of the present invention; Figure 2 This is an electron microscope photo of the microporous skeleton layer of polypropylene; Figure 3 This is an electron microscope photograph of a cross section of the microporous skeleton-based enhanced anion exchange membrane of the present invention; Figure 4 This is an electron microscope photograph of a cross section of the enhanced anion exchange membrane coated on both sides to form an anion exchange layer in Comparative Example 2; Figure 5 1 is a stress-strain curve diagram of each sample of Example 1, Comparative Example 1 and Comparative Example 2; Figure 6 This is an electron microscope photograph of the integrated membrane electrode of Application Example 1 of the present invention; Figure 7 This is an electron microscope photograph of the surface of the anode catalyst layer in the integrated membrane electrode of Application Example 1 of the present invention.

[0037] Explanation of reference numerals: 1-microporous skeleton layer, 2-anion exchange layer, 3-anode catalyst layer, 4-cathode catalyst layer, 11-anion exchange region, 12-cathode catalyst region. DETAILED DESCRIPTION

[0038] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The singular forms "a," "an," "the," and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, and unless the context clearly indicates otherwise, "a plurality" generally includes at least two.

[0040] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0041] A reinforced anion exchange membrane based on a microporous skeleton, see Figure 1-3 ,include: (1) a microporous skeleton layer 1, comprising at least one of a polyethylene film, a polypropylene film, a polyamide film, and a polytetrafluoroethylene film; the microporous skeleton layer is preferably hydrophilically modified; The microporous skeleton layer 1 includes an anion exchange region 11 and a blank region. The anion exchange region 11 is formed by filling part of the pores of the microporous skeleton layer 1 with an anion conductor material, and is formed on the side close to the anion exchange layer 2. From the side close to the anion exchange layer 2 to the inside, the anion conductor material forms a decreasing concentration gradient; the blank region, relative to the anion exchange region 11, is an unfilled microporous skeleton pore, and is mainly distributed on the other side of the microporous skeleton layer 1 away from the anion exchange layer 2.

[0042] (2) Anion exchange layer 2, laminated on one side of the microporous skeleton layer 1; anion exchange layer 2 comprises an anion conductor material; the anion exchange layer 2 and the anion conductor material in the anion exchange region 11 preferably form an integral structure. The anion conductor material comprises an aryl piperidine resin. Specifically, the anion conductor material is a resin material having anion exchange capacity formed by superacid-catalyzed polymerization of an aromatic polymer as a main chain and piperidine, imidazole, spiro ring, etc. as cationic functional groups.

[0043] For dimensions, see Figure 2 The thickness L0 of the microporous skeleton layer 1 is 5-60 μm, the porosity is 40-80%, and the pore size is 0.05-2 μm. Based on the total thickness L0 of the microporous skeleton layer 1: The thickness L1 of the anion exchange layer 2 satisfies: 2%×L0≤L1≤20%×L0; From the side close to the anion exchange layer 2 , the thickness L2 of the microporous skeleton layer 1 filled with the anion conductor material satisfies: 20%×L0≤L2<100%×L0.

[0044] The method for preparing the enhanced anion exchange membrane comprises the following steps: Step 1: Perform hydrophilic modification on the microporous skeleton layer 1: (1) preparing a hydrophilic modification solution, wherein one or more of ethylene-vinyl alcohol copolymer and dopamine are dissolved in an alcohol aqueous solution at a total concentration of 0.5-2.5 g / L, wherein the alcohol aqueous solution is obtained by mixing one or more of n-propanol, isopropanol, ethanol, and methanol with deionized water or the like in a certain proportion, wherein the mixing volume ratio of alcohol to water in the alcohol aqueous solution is preferably (1-5):(5-9); (2) Immersing the microporous skeleton in the hydrophilic modification solution, ultrasonically modifying the solution for 10-30 min, removing the excess solution on the surface, and drying the solution to obtain a microporous skeleton membrane layer with a hydrophilic surface.

[0045] Step 2: Prepare casting solution C1 and casting solution C2 containing anion conductor material: The casting solution is prepared by dissolving the anion conductor material in the desired mass fraction in one or more of the polar solvents dimethyl sulfoxide, N-methylpyrrolidone, and N,N-dimethylimide, and mixing them uniformly. The mass concentration of the casting solution is 10-30wt%, and the concentration of casting solution C1 is lower than that of casting solution C2. Preferably, the concentration of casting solution C1 is controlled at 10-25wt%, and the concentration of casting solution C2 is controlled at 20-30wt%. The casting solution C1 is preferably configured to include the casting solutions C1 with increasing concentrations. 1-1 , casting liquid C 1-2 , ... and casting solution C 1-n , n is a natural number greater than 1; for example, the casting solution C1 is divided into three casting solutions with increasing concentrations (i.e., n is 3 for example), the casting solution C 1-1 The concentration of the casting solution C can be selected from 10-15wt%. 1-2 The concentration of the casting solution C can be selected from 15-20wt%. 1-3 The concentration can be selected from 20-25wt%; Step 3: Apply the casting liquid C1 to one side of the microporous skeleton layer 1, and repeat the application several times after drying, so that the anion conductor material fills part of the pores of the microporous skeleton layer 1; preferably, the casting liquid C 1-1 , casting liquid C 1-2 , ... and casting solution C 1-n are applied and dried in sequence, so that the anion conductor material fills part of the pores of the microporous skeleton layer 1 and forms a decreasing concentration gradient from the outside to the inside; Step 4: applying the casting solution C2 to the side surface and vacuum drying to obtain the anion exchange layer 2 laminated on one side surface of the microporous skeleton layer 1 and the anion exchange region 11 close to the anion exchange layer 2 .

[0046] See also Figure 1 , 6-7, an integrated membrane electrode based on the enhanced anion exchange membrane, which comprises: (1) Anode catalyst layer 3, connected to anion exchange layer 2, including layered double hydroxide (LDH) catalyst with a loading of 2-20 mg / cm 2 ; (2) An enhanced anion exchange membrane comprising a microporous skeleton layer 1 and an anion exchange layer 2; the pores of the microporous skeleton layer 1 on the side close to the cathode catalyst layer 4 are at least partially filled with cathode catalyst to form a cathode catalyst region 12; (3) Cathode catalyst layer 4, including Pt / C catalyst, with a loading of 0.2-1.0 mg / cm 2 , connected to the other side of the microporous skeleton layer 1 away from the anion exchange layer 2, and forming an integrated structure with the cathode catalyst in the cathode catalytic region 12.

[0047] The method for preparing the integrated membrane electrode comprises the following steps: S1: preparing the enhanced anion exchange membrane, as described above, which will not be repeated here; S2: Prepare anode catalyst slurry and cathode catalyst slurry: The cathode catalyst slurry is prepared by mixing 30-60% Pt / C catalyst, ionomer, ethanol, and water in a mass ratio of 0.1-5:5-10:30-50:10-20; The ionomer is selected from at least one of poly(arylpiperidinium) polymers, polybenzimidazole polymers, polyfluorene polymers, and polyolefin polymers including polyethylene, polypropylene, and polybutene; The anode catalyst is an iron-cobalt-nickel double hydroxide obtained through a hydrothermal reaction of an iron-cobalt-nickel precursor. The anode catalyst slurry is prepared by mixing an LDH catalyst, a binder, a dispersant, and an organic solvent in a mass ratio of 20-50:5-15:5-8:40-60. The binder comprises a mixed solution containing 5-15wt% anionic ionomer and 2-6wt% polytetrafluoroethylene. The dispersant comprises a mixture of one or more of methanol, n-propanol, isopropanol, and ethanol. The organic solvent comprises a mixture of one or more of N-methylpyrrolidone, N,N-dimethylimide, and dimethyl sulfoxide.

[0048] S3: Apply the cathode catalyst slurry to the other side of the microporous skeleton layer away from the anion exchange layer, and fill part of the cathode catalyst into the pores of the microporous skeleton layer close to the cathode catalyst layer to form the cathode catalyst layer and the cathode catalytic area; the cathode catalyst slurry is applied by a spraying process, and the spraying process is selected from one of ultrasonic spraying, electrostatic spraying and manual spraying.

[0049] S4: forming the anode catalyst layer on the anion exchange layer using an anode catalyst slurry, preferably using a thermal transfer method, comprising: (1) Coating the anode catalyst slurry on the release film and drying it to obtain the anode catalyst thermal transfer sheet; the coating thickness is 20-100 μm, and the release film is selected from PTFE film or PET film, and the thickness is 50-200 μm; (2) Cover the anode catalyst thermal transfer sheet on the anion exchange layer of the enhanced anion exchange membrane; cover the cathode catalyst layer on the other side with a blank release film; (3) The anode catalyst layer is thermally transferred to the surface of the anion exchange layer of the enhanced anion exchange membrane on a hot press at a certain temperature and pressure, for example, a hot pressing temperature of 60-120°C, a hot pressing pressure of 2-10 MPa, and a time of 1-3 hours, to finally obtain an integrated membrane electrode with a "sandwich" structure in which the cathode catalyst layer and the anode catalyst layer are respectively covered on both sides.

[0050] Example 1 The enhanced anion exchange membrane of this embodiment includes a microporous skeleton layer 1 and an anion exchange layer 2. The microporous skeleton layer 1 is a polypropylene porous membrane with a thickness of about 20 μm, a porosity of 50±10%, and a pore size of 0.05-2 μm; the anion exchange layer 2 has a thickness of about 1.5 μm, and the maximum thickness of the formed anion exchange region 11 is about 14 μm.

[0051] The enhanced anion exchange membrane of this embodiment is prepared by the following steps: Step 1: Immerse the polypropylene microporous skeleton membrane in a 0.5 g / L ethylene-vinyl alcohol copolymer ethanol aqueous solution (ethanol and water volume ratio 5:5), ultrasonically treat for 30 min, then take it out, remove the excess solution on the surface, and dry it.

[0052] Step 2: Dissolve 1g of arylpiperidine resin in 10mL of dimethyl sulfoxide solvent to form a 15wt% casting solution C1. Dissolve 3g of arylpiperidine resin in 10mL of dimethyl sulfoxide solvent to form a 30wt% casting solution C2.

[0053] Step 3: Use a membrane frame to fix and tighten the hydrophilically modified polypropylene microporous skeleton layer. Use a brush to evenly apply a layer of 15wt% aryl piperidine resin casting liquid C1 on the first surface of the hydrophilic microporous skeleton layer. Repeat the brushing 5 times after drying. Finally, pour 30wt% aryl piperidine resin casting liquid C2 on the first surface to form a coating of about 20μm thick. Let it stand for 10 minutes, then scrape off the excess casting liquid on the first surface and place it in a vacuum drying oven for drying. Finally, an enhanced anion exchange membrane with only the first surface of the microporous skeleton layer 1 coated with anion exchange layer 2 and anion exchange region 11 is obtained. See Figure 3 .

[0054] Example 2 The difference between the enhanced anion exchange membrane of this embodiment and that of Example 1 is that the thickness of the microporous skeleton layer 1 is about 60 μm, the porosity is 50±10%, and the pore size is 0.05-2 μm; the thickness of the anion exchange layer 2 is about 2 μm, and the maximum thickness of the formed anion exchange region 11 is about 40 μm.

[0055] Example 3 The difference between the enhanced anion exchange membrane of this embodiment and that of Example 1 is that the thickness of the microporous skeleton layer 1 is about 10 μm, the porosity is 40±10%, and the pore size is 0.05-1 μm; the thickness of the anion exchange layer 2 is about 1 μm, and the maximum thickness of the formed anion exchange region 11 is about 7 μm.

[0056] Example 4 The difference between Example 4 and Example 1 is that the casting solution C1 is divided into three types and coated in sequence, including casting solution C 1-1 , casting liquid C 1-2 and casting solution C 1-3 The maximum thickness of the anion exchange region formed is about 16 μm. The enhanced anion exchange membrane of this embodiment is prepared by the following steps: Step 1: Perform hydrophilic modification on the microporous skeleton layer, as above; Step 2: Prepare casting solution C separately 1-1 , casting liquid C 1-2 , casting liquid C 1-3 and 30wt% of the casting solution C2, wherein the casting solution C 1-1 The concentration of 10wt%, casting solution C 1-2 The concentration of 15wt%, casting solution C 1-3 The concentration is 20wt%.

[0057] Step 3: Use the membrane frame to fix and tighten the hydrophilic modified polypropylene microporous skeleton layer. Use a brush to evenly apply a layer of casting liquid C on the first surface of the hydrophilic microporous skeleton layer. 1-1After drying, evenly apply a layer of casting liquid C 1-2 After drying, evenly apply a layer of casting liquid C 1-3 And dried, and finally 30wt% concentration of aromatic piperidine resin casting liquid C2 was poured and spread on the first surface to form a coating of about 20μm thick, and allowed to stand for 10 minutes, and then the excess casting liquid on the first surface was scraped off and placed in a vacuum drying oven for drying, finally obtaining an enhanced anion exchange membrane with only the first surface of the microporous skeleton layer coated with an anion exchange layer on one side and having an anion exchange region.

[0058] Comparative Example 1 Dissolve 1.5g of arylpiperidine resin in 10mL of dimethyl sulfoxide to form a 15wt% casting solution. Pour this solution onto a 15x15cm glass slide and allow it to fully self-level for 30 minutes, forming a coating approximately 40μm thick. Dry at 65°C for 6 hours, then at 80°C under vacuum for 2 hours to obtain a homogeneous anion exchange membrane.

[0059] Comparative Example 2 Comparative Example 2 uses the same microporous skeleton layer 1 as in Example 1 to prepare its anion exchange membrane by the following steps: (1) The polypropylene microporous skeleton membrane was immersed in a 0.5 g / L ethylene-vinyl alcohol copolymer ethanol aqueous solution (ethanol and water volume ratio 5:5), ultrasonically treated for 30 min, then taken out, excess solution on the surface was removed, and dried.

[0060] (2) The hydrophilically modified polypropylene microporous skeleton membrane was immersed in a 15 wt% concentration of aryl piperidine resin casting solution C1 and ultrasonically treated for 30 minutes. After being taken out and dried, the above steps were repeated 5 times. The treated membrane was fixed with a membrane frame, and a 30 wt% concentration of aryl piperidine resin casting solution C2 was scraped on the first surface to form a 20 μm thick coating. The membrane was placed in a vacuum drying oven for drying. Subsequently, a 30 wt% concentration of aryl piperidine resin casting solution C2 was scraped on the second surface to form a 20 μm thick coating. After drying, an anion exchange membrane with double-sided anion exchange layer was finally obtained. See Figure 4 .

[0061] Test standards The samples prepared in Examples 1-4 and Comparative Examples 1 and 2 were tested according to the following standards: 1. Tensile strength: The test method is based on ASTM D638-14 standard. Alkaline anion exchange membrane is cut into dumbbell shape and tested on a tensile testing machine. 2. Elongation at break: The elongation at break was tested using an Instron 6800 universal tensile testing machine.

[0062] 3. Dimensional change rate at 80°C: Cut a 30 mm × 40 mm piece of alkaline anion exchange membrane and immerse it in a 1 M KOH solution at 80°C. Calculate the length expansion rate based on the length growth after 24 hours.

[0063] 4. 80°C Ionic Conductivity: The ionic conductivity of the membranes was determined by electrochemical impedance spectroscopy (EIS) at 80°C. Specifically, the test sample was cut into a 10 cm diameter circular shape and clamped in a laboratory-made apparatus using platinum wire electrodes (a four-probe electrode). The humidity within the test cell was controlled using nitrogen gas with water vapor. The resistance values obtained from the Nyquist plot were used to calculate the ionic conductivity of the membranes. The ionic conductivity of each membrane was defined using the following formula: σ = L / AR, where σ represents the ionic conductivity, L represents the distance between the reference electrodes, A represents the membrane area, and R represents the resistance of the sample.

[0064] Test results The main structural parameters and performance test results of Examples 1-4 and Comparative Examples 1-2 are shown in Table 1: Table 1

[0065] By providing a microporous skeleton layer, the tensile strength of each example was above 50 MPa, and the elongation at break was above 150%. Compared with Comparative Example 1, which did not use a microporous skeleton layer, the mechanical properties of the examples were significantly improved. Comparative Example 2, which also used a microporous skeleton layer, had improved tensile strength, but due to the full filling of the anion exchange material, the overall softness and elasticity of the anion exchange membrane were not as good as those of the examples.

[0066] Comparative Example 1 lacks the support and framework of the microporous skeleton layer. Although its ion conductivity is relatively high, it swells severely at 80°C and changes in size too much, resulting in a rapid decline in the life of the anion exchange membrane. In Comparative Example 2, the degree of swelling in the part supported and protected by the microporous skeleton layer is low, but the thicker anion exchange layers on both sides still swell and lose at high temperatures. The overall degree of swelling and deformation is lower than that of Comparative Example 1, but the ion conductivity is relatively low. The embodiments of the present invention have good anti-swelling properties at high temperatures, with a dimensional change rate of less than 1.5% at 80°C, an ionic conductivity of more than 1.75mS / cm, and good overall stability and durability.

[0067] Application Example 1 Application Example 1: Based on the enhanced anion exchange membrane prepared in the previous embodiment, an integrated membrane electrode is further obtained, including the following steps: S1: using the enhanced anion exchange membrane of Example 1; S2: Prepare anode catalyst slurry and cathode catalyst slurry: (1) Dissolve 5 g of ionomer in 40 g of ethanol and 10 g of water, then add 1 g of 50% Pt / C catalyst while magnetic stirring. After dispersion is complete, ultrasonic treatment is performed for 10 min to obtain cathode catalyst slurry.

[0068] (2) 30 g of LDH catalyst was mixed with 6 g of 10 wt% anionic ionomer and 6 g of 5 wt% polytetrafluoroethylene mixed solution, 8 g of isopropanol and 50 g of dimethyl sulfoxide solvent, and then ultrasonically treated for 10 min and vacuum degassing for 5 min to obtain the anode catalyst slurry.

[0069] S3: The enhanced anion exchange membrane obtained in Example 1 was adsorbed on the heating platform of the ultrasonic spraying instrument, with the side not coated with the anion conductor material facing up. A layer of cathode catalyst slurry was applied at a syringe pump feed rate of 1.5 mL / min, an effective spraying area of 3 cm×3 cm, and a heating platform temperature of 90°C. The Pt / C catalyst loading was controlled at 0.8 mg / cm 2 .

[0070] S4: applying the anode catalyst slurry to the anion exchange layer by thermal transfer to form an anode catalyst layer, comprising: (1) Adsorb the PTFE release film on the surface of the slot coating machine, and coat a layer of anode catalyst slurry on the release film surface at a coating speed of 0.5m / min. After drying, the anode catalyst transfer sheet is obtained. The LDH catalyst loading is controlled at 8mg / cm 2 .

[0071] (2) The anode catalyst transfer sheet is covered on the anion exchange layer of the enhanced anion exchange membrane, that is, the side not covered with the cathode catalyst, and the other side covered with the cathode catalyst is covered with a blank release film.

[0072] (3) Using a hot press, the anode LDH catalyst was thermally transferred to the surface of the enhanced anion membrane at 90°C and 5 MPa pressure for 2 hours to form an anode catalyst layer, and finally an integrated membrane electrode with a cathode catalyst layer and an anode catalyst layer on both sides was obtained.

[0073] Application Example 2 The difference between Application Example 2 and Application Example 1 is that in step S3, the loading of the Pt / C catalyst is controlled at 0.3 mg / cm 2 .

[0074] Application Example 3 The difference between Application Example 3 and Application Example 1 is that in step S4, the loading of LDH catalyst is controlled at 15 mg / cm 2 .

[0075] Application Example 4 The difference between Application Example 4 and Application Example 1 is that the enhanced anion exchange membrane of Example 4 is used, and the other preparation steps are the same.

[0076] Application Comparison 1 The difference between Application Comparison 1 and Application Example 1 is that both the cathode catalyst layer and the anode catalyst layer are formed by thermal transfer and hot pressing at the same time, including the following steps: S1: using the enhanced anion exchange membrane of Example 1; S2: preparing anode catalyst slurry and cathode catalyst slurry, same as above; S3: Adsorb the PTFE release film onto the heating platform of the ultrasonic spraying instrument, and apply a layer of cathode catalyst slurry on it at a syringe pump feed rate of 1.5 mL / min, a spraying effective area of 3 cm×3 cm, and a heating platform temperature of 90°C. After drying, the cathode catalyst transfer sheet is obtained. The Pt / C catalyst loading is controlled at 0.8 mg / cm 2 .

[0077] The PTFE release film is adsorbed on the surface of the slot coating machine. A layer of anode catalyst slurry is coated on the release film surface at a coating speed of 0.5m / min. The anode catalyst transfer sheet is obtained by drying. The LDH catalyst loading is controlled at 8mg / cm 2 .

[0078] S4: Cover the cathode catalyst transfer sheet on the side of the enhanced anion exchange membrane in Example 1 that is not coated with the anion conductor material, and cover the anode catalyst transfer sheet on the anion exchange layer on the other side. Then, place it on a hot press at 90°C and 5MPa pressure for 2 hours to finally obtain a membrane electrode with a cathode catalyst layer and an anode catalyst layer on both sides respectively.

[0079] Application Comparison 2 The difference between Application Comparison 2 and Application Comparison 1 is that the anion exchange membrane coated with anion exchange layers on both sides of Comparative Example 2 is used to obtain a membrane electrode with a cathode catalyst layer and an anode catalyst layer coated on both sides respectively.

[0080] Application comparison 3: The difference between Application Comparison 3 and Application Comparison 1 is that the preparation method steps are different. The specific preparation method is as follows: S1: using the enhanced anion exchange membrane of Example 1; S2: Prepare anode catalyst slurry and cathode catalyst slurry: (1) Dissolve 5 g of ionomer in 40 g of ethanol and 10 g of water, then add 1 g of 50% Pt / C catalyst while magnetic stirring. After dispersion is complete, ultrasonic treatment is performed for 10 min to obtain cathode catalyst slurry.

[0081] (2) 30 g of LDH catalyst was mixed with 6 g of 10 wt% ionomer solution, 6 g of 5 wt% polytetrafluoroethylene solution, 8 g of isopropanol and 50 g of dimethyl sulfoxide solvent, and then ultrasonically treated for 10 min and vacuum degassing for 5 min to obtain the anode catalyst slurry.

[0082] S3: Fix the conductive carbon cloth on the heating platform of the ultrasonic spraying instrument, press the syringe pump feed rate of 1.5mL / min; spray the effective area of 3cm×3cm; and coat a layer of catalyst slurry on the heating platform at 90℃. After drying, a cathode catalyst membrane electrode in the form of CCS is obtained. The Pt / C catalyst loading is controlled at 0.8mg / cm 2 .

[0083] S4: A 50 μm thick layer of anode catalyst slurry is coated on the surface of the porous nickel mesh at a coating speed of 0.5 m / min. The anode catalyst membrane electrode in the form of CCS is obtained by drying. The LDH catalyst loading is controlled at 8 mg / cm 2 .

[0084] S5: Cover the cathode catalyst membrane electrode and the anode catalyst membrane electrode obtained in step S3 and step S4 on both sides of the single-sided coated enhanced anion exchange membrane obtained in Example 1, and then combine the cathode / anode catalyst membrane electrode and the enhanced anion exchange membrane together on a hot press at 90°C and 5MPa pressure.

[0085] Application Comparison 4 The difference between Application Comparison 4 and Application Comparison 3 is that the single-side coated enhanced anion exchange membrane obtained in Example 4 is used in step S5.

[0086] Application Comparison 5 The difference between Application Comparison 5 and Application Comparison 3 is that the double-sided coating enhanced anion exchange membrane obtained in Comparative Example 2 is used in step S5.

[0087] Test standards 1. Membrane electrode interface resistivity: ASTM F84, GB / T1551, GB / T1552 are used as reference test standards; Current density at 2.2V constant voltage: Refer to GB / T 20042.5-2009: Chinese national standard "Proton exchange membrane fuel cells Part 5: Membrane electrode test methods".

[0088] Test results The main parameters and performance test results of application examples 1-4 and application comparisons 1-5 are shown in Table 2: Table 2

[0089] The membrane electrode interface resistivity of each application example is below 0.2Ω·cm, and the current density is 1.2A / cm at a constant voltage of 2V. 2 As above. The present invention adopts a liquid slurry coating method to apply the cathode catalyst slurry, so that it can be gradually impregnated into the pores on the opposite side of the microporous skeleton layer and the anion exchange layer, which not only stably undertakes the load of the cathode catalyst slurry, but also helps to improve its load stability. After the anode catalyst slurry is applied to the other side by transfer printing, the cathode catalyst layer and the anode catalyst layer are hot-pressed together at the same time, the process is simple, and the molding effect is good. Compared with application comparisons 1 and 2, which only use a single thermal transfer and hot pressing molding method, the present invention not only fully utilizes the structural advantages of the microporous skeleton layer, but also selects a material application method that is more suitable for its structure, thereby obtaining an integrated membrane electrode product with better comprehensive performance.

[0090] In comparison, Application Comparison 5 uses the double-sided coated anion exchange membrane of Comparative Example 2 and combines it with the CCS process to prepare a membrane electrode. Its interface resistivity is 0.25 Ω·cm, and the current density at a constant voltage of 2V is only 0.95 A / cm², which is significantly inferior to Application Examples 1-4 and Application Comparisons 1-4.

[0091] The above comparison verifies the innovativeness of the single-sided gradient coating and asymmetric loading process of the present invention: through the pore regulation of the microporous skeleton layer and the differentiated processing strategy of the anode and cathode, while ensuring the mechanical strength (tensile strength ≥ 55.8 MPa), the interface resistivity and current density are simultaneously optimized, providing a reliable technical path for the engineering preparation of high-durability anion exchange membrane electrodes.

[0092] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. An enhanced anion exchange membrane based on a microporous skeleton, characterized in that: It includes a microporous skeleton layer and an anion exchange layer laminated on one side of the microporous skeleton layer; The anion exchange layer includes an anion conductor material; The anion conductor material fills part of the pores of the microporous skeleton layer to form an anion exchange region on the side close to the anion exchange layer; In the anion exchange region, the concentration gradient of the anion conductor material gradually decreases from the side close to the anion exchange layer toward the inside.

2. The enhanced anion exchange membrane according to claim 1, wherein The microporous skeleton layer includes at least one of a polyethylene film, a polypropylene film, a polyamide film, and a polytetrafluoroethylene film; The thickness of the microporous skeleton layer is 5-60 μm, the porosity is 40-80%, and the pore size is 0.05-2 μm.

3. The enhanced anion exchange membrane according to claim 2, wherein The microporous skeleton layer is subjected to a hydrophilic modification treatment, comprising the following steps: preparing a hydrophilic modification solution, wherein the hydrophilic modification solution comprises one or more of ethylene-vinyl alcohol copolymer and dopamine; The microporous skeleton is immersed in the hydrophilic modification solution and subjected to ultrasonic modification treatment.

4. The enhanced anion exchange membrane according to any one of claims 1 to 3, characterized in that The anion conductor material includes an arylpiperidine resin.

5. The enhanced anion exchange membrane according to claim 4, characterized in that Calculated based on the total thickness L0 of the microporous skeleton layer: The thickness L1 of the anion exchange layer satisfies: 2%×L0≤L1≤20%×L0; From the side close to the anion exchange layer, the thickness L2 of the microporous skeleton layer filled with the anion conductor material satisfies: 20%×L0≤L2<100%×L0.

6. A method for preparing the enhanced anion exchange membrane according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: hydrophilic modification of the microporous skeleton layer; Step 2: preparing a casting solution C1 and a casting solution C2 containing an anion conductor material, wherein the concentration of the casting solution C1 is lower than that of the casting solution C2; Step 3: Apply the casting solution C1 to one side of the microporous skeleton layer, and repeat the application several times after drying, so that the anion conductor material fills part of the pores of the microporous skeleton layer; Step 4: applying the casting solution C2 to the side surface and vacuum drying to obtain an anion exchange layer laminated on one side surface of the microporous skeleton layer and an anion exchange region close to the anion exchange layer.

7. The preparation method according to claim 6, wherein In step 2, the casting solution C1 is configured to contain casting solutions C with increasing concentrations. 1-1 , casting liquid C 1-2 , ... and casting solution C 1-n , n is a natural number greater than 1; In step 3, the casting solution C 1-1 , casting liquid C 1-2 , ... and casting solution C 1-n The anion conductor materials are applied and dried sequentially, so that the anion conductor materials fill part of the pores of the microporous skeleton layer and form a decreasing concentration gradient from the outside to the inside.

8. An integrated membrane electrode based on the enhanced anion exchange membrane according to any one of claims 1 to 5, characterized in that: It includes an anode catalyst layer, an enhanced anion exchange membrane and a cathode catalyst layer in sequence; The anode catalyst layer is connected to the anion exchange layer; The cathode catalyst layer is connected to the other side of the microporous skeleton layer away from the anion exchange layer; The pores of the microporous skeleton layer on the side close to the cathode catalyst layer are at least partially filled with cathode catalyst to form a cathode catalyst region.

9. The integrated membrane electrode according to claim 8, characterized in that: Meet at least one of the following characteristics: 1) The anode catalyst layer includes a layered double hydroxide (LDH) catalyst with a loading of 2-20 mg / cm 2 ; 2) The cathode catalyst layer includes a Pt / C catalyst with a loading of 0.2-1.0 mg / cm 2 .

10. A method for preparing the integrated membrane electrode according to claim 8 or 9, characterized in that: The steps include: S1: preparing the enhanced anion exchange membrane; S2: preparing anode catalyst slurry and cathode catalyst slurry; S3: applying the cathode catalyst slurry to the other side of the microporous skeleton layer away from the anion exchange layer, and filling part of the cathode catalyst into the pores of the microporous skeleton layer close to the cathode catalyst layer to form the cathode catalyst layer and the cathode catalyst region; S4: forming the anode catalyst layer on the anion exchange layer using an anode catalyst slurry.

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