A method for preparing a membrane electrode assembly for anion exchange membrane water electrolysis and its application.

Abstract

This invention belongs to the field of membrane electrode technology, specifically relating to a method for preparing a membrane electrode assembly for anion exchange membrane electrolysis of water and its application. This invention proposes an integrated preparation strategy of "cathode CCS—in-situ film formation—anode CCS": first, a hydrogen evolution catalyst layer is coated onto the cathode gas diffusion layer, then an anion exchange membrane precursor is directly coated onto it and cured in situ, achieving an integrated combination of the cathode catalyst layer and the AEM membrane; the anode gas diffusion layer is then sequentially coated with a resin layer and an oxygen evolution catalyst layer; finally, it is assembled by gentle hot pressing. This method eliminates the need for high-temperature, high-pressure transfer printing, has a wide process window, avoids the risk of membrane breakage, and significantly reduces interfacial resistance.

Description

Technical Field

[0001] This invention belongs to the field of membrane electrode technology, specifically relating to a method for preparing a membrane electrode assembly for anion exchange membrane electrolysis of water and its application. Background Technology

[0002] Anion exchange membrane electrolysis (AEMWE) technology combines the low-cost advantage of using non-precious metal catalysts in alkaline water electrolysis with the high efficiency and compactness of proton exchange membrane electrolysis, making it a current research hotspot. Its core component, the membrane electrode assembly (MEA), typically has a structure of "anodide diffusion layer - anodic catalyst layer - AEM membrane - cathode catalyst layer - cathode diffusion layer".

[0003] Currently, the mainstream fabrication methods for AEMWE film electrodes include the following two: 1. CCM method (catalyst coating membrane method): The anode and cathode catalyst layers are directly applied to both sides of the finished AEM membrane, which includes direct coating method and hot pressing transfer method.

[0004] (1) Direct coating method: The catalyst layer slurry is directly sprayed or scraped onto the surface of the AEM membrane, and then assembled with the gas diffusion layer after drying. In this method, the organic solvent in the catalyst layer slurry can easily cause the AEM membrane to swell and deform during the coating process, affecting the coating accuracy and the mechanical integrity of the membrane. Moreover, the interfacial adhesion decreases during long-term operation, making it prone to peeling.

[0005] (2) Hot-press transfer method: The catalyst layer is first coated on the transfer substrate (such as PTFE membrane), and then the catalyst layer is transferred to the surface of the AEM membrane by hot pressing. This method is extremely sensitive to the hot pressing temperature, and in practice, it is often difficult to find a suitable process window: if the temperature is slightly too high, the moisture in the AEM membrane will evaporate rapidly, causing the membrane to lose water and become brittle, and it cannot be recovered; if the temperature is insufficient, the catalyst layer cannot be transferred at all, or the transfer is incomplete and the adhesion is extremely poor. In fact, many AEM membrane materials do not have an operable transfer temperature range under this method, making it impossible to prepare CCM.

[0006] 2. CCS method (catalyst-coated substrate method): The catalyst layer is coated onto the anode and cathode gas diffusion layers respectively, and then hot-pressed onto the AEM membrane. This method avoids the membrane swelling problem, but the interfacial bonding between the membrane and the catalyst layer mainly relies on hot-pressing physical contact. The interfacial resistance is high and the contact is not tight. During long-term electrolysis operation, delamination is prone to occur, leading to performance degradation.

[0007] Therefore, how to balance membrane integrity, interfacial adhesion, low resistance, and low cost in the fabrication of AEMWE membrane electrodes, and solve the problems of easy membrane swelling, missing hot-pressing windows (resulting in transfer failure or membrane breakage), high interfacial resistance, poor adhesion, and insufficient stability in existing technologies, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments.

[0009] As one aspect of the present invention, the present invention provides a method for preparing a membrane electrode assembly for anion exchange membrane electrolysis of water, which includes the following steps: (1) Preparation of cathode catalyst coating substrate: The hydrogen evolution reaction catalyst, anion exchange resin and solvent are mixed to obtain cathode catalyst slurry, the cathode catalyst slurry is coated on one side of the cathode gas diffusion layer and dried to obtain cathode CCS; (2) In-situ preparation of AEM membrane on cathode CCS: The anion exchange membrane precursor solution is coated on the surface of the catalyst layer of the cathode CCS and cured to obtain an AEM membrane with a dry membrane thickness of 40~80μm, and the AEM membrane is integrally formed with the cathode catalyst layer. (3) Preparation of anode catalyst coating substrate: A resin layer slurry and an anode catalyst layer slurry are sequentially coated on one side of the anode gas diffusion layer and dried to obtain anode CCS; the resin layer slurry is made by mixing anion exchange resin solution and solvent; the anode catalyst layer slurry is made by mixing oxygen evolution reaction catalyst, anion exchange resin and solvent; (4) Assembly: The cathode CCS-AEM membrane assembly obtained in step (2) and the anode CCS obtained in step (3) are stacked with the anode catalyst layer facing the AEM membrane, and hot-pressed to obtain the membrane electrode assembly.

[0010] As a preferred embodiment of the method described in this invention, in step (1), the hydrogen evolution reaction catalyst is selected from at least one of Pt / C, PtRu / C, and Ni3N / nitrogen-doped carbon; the drying temperature is 50~80℃, the drying time is 4~12 hours, the mass ratio of the hydrogen evolution reaction catalyst to the anion exchange resin is (60~90):(10~40); and the mass ratio of the hydrogen evolution reaction catalyst to the solvent is 1:20~100.

[0011] As a preferred embodiment of the method described in this invention, in step (2), the anion exchange membrane precursor solution is a polyarylpiperidine-onium polymer solution with a solid content of 10~20wt%; the curing temperature is 40~80℃ and the curing time is 0.5~6 hours.

[0012] As a preferred embodiment of the method described in this invention, in step (3), the anion exchange resin in the resin layer slurry is a quaternary ammonium salt type resin or a polyarylpiperidine type resin, and the solvent is a mixture of isopropanol and water, with a volume ratio of isopropanol to water of (8~9.5):(0.5~2).

[0013] As a preferred embodiment of the method described in this invention, in step (3), the oxygen evolution reaction catalyst is selected from at least one of NiFe-LDH, CuCo2O4, and NiFeCo-based ternary metal oxides; in the anode catalyst slurry, the mass ratio of the oxygen evolution reaction catalyst to the anion exchange resin is (60~90):(10~40), and the mass ratio of the oxygen evolution reaction catalyst to the solvent is 1:20~100.

[0014] As a preferred embodiment of the method described in this invention, in step (3), the drying temperature is 70~90℃ and the drying time is 4~8 hours.

[0015] As a preferred embodiment of the method described in this invention, in step (4), the hot pressing temperature is 80~130℃, the hot pressing pressure is 0.5~2MPa, and the hot pressing time is 1~5 minutes.

[0016] As a preferred embodiment of the method described in this invention, in step (3), the dry film thickness of the resin layer is 1~5μm.

[0017] As a preferred embodiment of the method described in this invention, in step (2), the coating method of the anion exchange membrane precursor solution is blade coating, and the wet film thickness is controlled to be 400~550μm by the gap between the blades.

[0018] The beneficial effects of this invention are: 1) Strong interfacial bonding and low resistance: The cathode catalyst layer of this invention is integrated with the AEM membrane (anion exchange membrane), which eliminates the physical interface in the traditional CCS method and effectively reduces the ohmic resistance; the anode resin layer further improves ion conduction.

[0019] 2) This invention solves the problem of membrane breakage and has a wide process window: there is no need to perform hot pressing transfer or solvent coating on the finished membrane, fundamentally avoiding the risk of membrane dehydration, brittleness, breakage, and scrapping. The AEM membrane curing conditions are flexible (temperature 40-80℃), and subsequent hot pressing is only used for the gentle bonding of the anode CCS to the membrane, making the process window much wider than that of the CCM hot pressing transfer method.

[0020] 3) Significant cost advantage: It is fully compatible with non-precious metal catalysts, and both the resin layer and AEM precursor can be made of low-cost materials.

[0021] 4) Performance Improvement: Using the method of this invention, in Example 1, the current density reaches 1.5 A / cm² at a voltage of 1.8V. 2 It has excellent durability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, wherein: Figure 1 This is a schematic diagram of the membrane electrode assembly structure according to an embodiment of the present invention.

[0023] In the diagram: 1—Cathode gas diffusion layer (carbon paper); 2—Cathode catalyst layer (HER catalyst and resin); 3—In-situ formed AEM membrane; 4—Anode resin layer (pure anion exchange resin layer); 5—Anode catalyst layer (OER catalyst and resin); 6—Anode gas diffusion layer (nickel foam).

[0024] Figure 2 This is a comparison diagram of the polarization curves of the present invention and a comparative example.

[0025] Figure 3 The constant current (1A / cm) of the present invention and comparative examples 2 Operational stability comparison chart (voltage-time curve). Detailed Implementation

[0026] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0027] This invention proposes a method for preparing a membrane electrode consisting of "cathode CCS—in-situ film formation—anode CCS (with resin layer)". The specific steps are as follows: Step 1: Preparation of the cathode CCS (Catalyst Coated Substrate) The cathode catalyst slurry is directly coated onto one side of a hydrophobically treated porous gas diffusion layer (such as carbon paper, carbon cloth, or carbon fiber felt, or a nickel-based material). Coating methods include spraying, blade coating, screen printing, or slot coating. Vacuum drying is then performed at 50–80°C for 4–12 hours. The preferred drying temperature is 60–70°C, and the drying time is 6–8 hours.

[0028] The cathode catalyst slurry is composed of a hydrogen evolution reaction (HER) catalyst, anion exchange resin, and solvent. The mass ratio of catalyst to resin is 60-90% : 40-10% (preferably 70-80% : 30-20%); the mass ratio of catalyst to solvent is 1:20-100 (preferably 1:30-50). HER catalysts can be selected from, but are not limited to, Pt / C (20-60 wt%), PtRu / C, PtNi / C, Ru / C, non-noble metal Ni3N / nitrogen-doped carbon, Ni-Mo alloy, MoNi4 / MoO2, etc. 20-40 wt% Pt / C is preferred.

[0029] Step 2: In-situ preparation of AEM film on cathode CCS The precursor solution for the anion exchange membrane is directly coated onto the catalytic layer surface of the cathode CCS, integrating the membrane with the cathode catalytic layer. This can be achieved using either a blade coating or a slot coating method. Blade coating is preferred due to its ease of operation, simple equipment, and lower loss in small batches. The wet membrane thickness is controlled by the blade gap or slot width, with the final dry membrane thickness controlled at 40–80 μm, preferably 50–75 μm. The curing / crosslinking reaction is carried out at 40–80°C for 0.5–6 hours, preferably at 60–80°C for 2–4 hours. For non-functionalized precursors, after curing, immersion in a 1–2M KOH or NaOH solution for 12–48 hours is required for ion exchange, converting it to the OH- form. The precursor is then washed with deionized water until neutral and vacuum dried. The AEM precursor solution can be selected from polymers without aryl ether bonds, such as polyarylpiperidinium (PAP) and quaternized polyphenylene ether, and dissolved in dimethyl sulfoxide (DMSO) or N-methylpyrrolidone (NMP), with a solid content of 10~20wt%.

[0030] Step 3: Prepare the anode CCS (with resin layer) A resin layer and an anode catalyst layer are sequentially coated on one side of the anode gas diffusion layer (such as nickel foam, nickel mesh, or nickel-plated stainless steel mesh).

[0031] Resin layer slurry preparation: The resin layer slurry is prepared by mixing anion exchange resin solution and a solvent. Taking a quaternary ammonium salt type resin (such as Tokuyama AS-4, 5wt% solution) as an example, 0.05g of the resin solution can be mixed with 0.95g of isopropanol / water (volume ratio 9:1) and ultrasonically dispersed for 0.5 to 2 hours until homogeneous. This resin layer does not contain a catalyst and is only a pure ion conductor resin layer, with the dry film thickness controlled at 1 to 5 μm. The resin can be selected from quaternary ammonium salt type, imidazolium type (such as Sustainion), polyarylpiperidineonium type (such as PiperION), etc.; the solvent can be selected from isopropanol, n-propanol, ethanol, deionized water or mixtures thereof, preferably isopropanol / water (volume ratio 9:1 or 8:2).

[0032] Preparation of anode catalyst layer slurry: The mixture comprises an oxygen evolution reaction (OER) catalyst, anion exchange resin, and solvent. The mass ratio of catalyst to resin is 60-90% : 40-10% (preferably 70-85% : 30-15%); the mass ratio of catalyst to solvent is 1:20-100. OER catalysts can be selected from, but are not limited to, NiFe-LDH (Fe molar ratio 5-15%), NiFeCo-based ternary metal oxides, and Cu... 0.7 Co 2.3 O4, CuCo2O4 nanoparticles; IrO2 (rutile or amorphous IrO) x ); perovskites such as Ba 0.5 Sr0.5 Co 0.8 Fe 0.2 O3-δ. NiFe-LDH (Fe molar ratio 10%) is preferred.

[0033] Coating and drying: First, apply the resin slurry to one side of the anode gas diffusion layer, and then apply the anode catalyst slurry after it is semi-dry (or immediately). The coating method can be spraying, scraping, or screen printing. Vacuum dry at 60~100℃ for 4~8 hours. Preferably, dry at 80℃ for 6 hours.

[0034] Step 4: Assemble the membrane electrode assembly (MEA) The "cathode CCS-AEM membrane" assembly obtained in step 2 and the anode CCS obtained in step 3 are stacked with the anode catalyst layer facing the AEM membrane, and then subjected to hot pressing. The hot pressing temperature, pressure, and time can be selected within a wide range according to the characteristics of the selected anion exchange membrane and anion exchange resin. As a general reference, the hot pressing temperature can be 80~130℃, the pressure 0.5~2MPa, and the time 1~5 minutes. Unlike the CCM hot pressing transfer method, in this invention, the subsequent hot pressing is only used to gently bond the anode CCS to the in-situ formed AEM membrane. Therefore, the sensitivity to hot pressing parameters is significantly reduced, and the process window tolerance is greatly improved. As an example, for some quaternary ammonium salt AEM membranes, the preferred hot pressing conditions are a temperature of 100~120℃, a pressure of 1~1.5MPa, and a time of 2~3 minutes. After hot pressing, the membrane is naturally cooled to room temperature to obtain a complete membrane electrode assembly, the structure of which is as follows: cathode gas diffusion layer - cathode catalyst layer - AEM membrane - resin layer - anode catalyst layer - anode gas diffusion layer.

[0035] Product structure and working principle of this invention: Product structure: Cathode CCS: It consists of a cathode gas diffusion layer (porous carbon fiber or nickel substrate) and a cathode catalyst layer (HER catalyst and ion exchange resin) coated on it.

[0036] AEM membrane: It is formed directly on the cathode catalyst layer through in-situ coating and curing, integrating the three into one, without physical interface.

[0037] The anode CCS consists of an anode gas diffusion layer (nickel-based porous material), an anode resin layer (pure ion exchange resin layer), and an anode catalyst layer (OER catalyst and ion exchange resin). The resin layer, located between the AEM membrane and the anode catalyst layer, is rich in anion exchange resin, acting as an "ion bridge" to increase the OH- ion exchange capacity. - It forms a conductive interface and buffers the internal stress that may be generated between the anode catalyst layer and the film due to the difference in swelling ratio.

[0038] Working principle: Under alkaline or pure water electrolysis conditions, the electrolyte (e.g., 1M KOH) is supplied to the anode side. The oxygen evolution reaction (OER) occurs in the anode catalyst layer: 4OH⁻ - → O2 + 2H2O + 4e - H2O is conducted to the cathode catalyst layer through the anode resin layer and AEM membrane. On the cathode side, water combines with electrons to undergo the hydrogen evolution reaction (HER): 4H2O + 4e- - → 2H2+ 4OH - OH - The ion is returned to the anode via an AEM membrane and a transition layer. In this invention, the integrated cathode structure and anode resin layer significantly reduce ion conduction resistance and expand the three-phase reaction interface, thereby improving electrolysis efficiency and stability.

[0039] Example 1: Step 1: Preparation of cathode CCS Hydrophobically treated carbon paper (General Hydrogen Energy GH-GDB-40) was selected as the cathode gas diffusion layer, with an area of ​​4 cm². 2 Take 0.014 g of 50 wt% Pt / C catalyst (model TEC10E50E, Tanaka Precious Metals), first add 0.3 g of deionized water to wet the catalyst, then add 0.55 g of isopropanol (water to isopropanol volume ratio approximately 3:7), and ultrasonically disperse for 30 minutes. Then add 0.18 g of 5 wt% AS-4 anion exchange resin (Tokuyama) solution, and continue ultrasonic dispersion for 30 minutes to obtain the cathode catalyst slurry. The slurry is uniformly sprayed onto one side of carbon paper using a spraying method, with the platinum loading controlled at 0.2 mg / cm³. 2 The cathode CCS was obtained by vacuum drying at 60°C for 6 hours.

[0040] Step 2: In-situ preparation of AEM membrane The PAP (polyarylpiperidinium) precursor was synthesized according to the method described in CN117164913A: Bisphenyl and N-methyl-4-piperidinone were subjected to trifluoromethanesulfonic acid-catalyzed polycondensation, followed by quaternization with iodomethane and crosslinking with 1,6-dibromohexane to obtain a crosslinked polyarylpiperidinium polymer with an IEC of approximately 2.2 meq / g. The obtained polymer was dissolved in DMSO to prepare a solution with a solid content of 15 wt%, stirred at 60°C for 12 hours, and allowed to stand to remove bubbles. The above solution was coated onto the surface of the cathode CCS catalyst layer with a scraper gap of 450 μm, cured at 80°C for 3 hours, and thoroughly dried to form an AEM membrane with a dry film thickness of approximately 50 μm. The obtained cathode CCS-AEM membrane assembly was immersed in 1M KOH solution for 24 hours for ion exchange, washed with deionized water until neutral, and vacuum dried at 60°C to obtain an OH-type cathode CCS-AEM membrane assembly.

[0041] Step 3: Prepare the anode CCS (with resin layer) Nickel foam (0.5 mm thick) was selected as the anode gas diffusion layer, with an area of ​​4 cm². 2 .

[0042] Resin layer slurry: 0.05g of 5wt% AS-4 resin solution, 0.12g of water, and 0.83g of isopropanol (water to isopropanol volume ratio 1:9), ultrasonicated for 40min, sprayed onto nickel foam, controlling the resin loading to approximately 0.05mg / cm³. 2 .

[0043] Anode catalyst slurry: 0.08 g of nickel-iron layered double hydroxide NiFe-LDH (Fe molar ratio 10%, Jiangsu Xianfeng Nano, product number 102593), 1.58 g of isopropanol, and 1.62 g of n-propanol (isopropanol to n-propanol volume ratio 1:1) were added. The mixture was sonicated for 40 min, then 0.8 g of 5 wt% PiperION resin (Versogen) solution was added, and sonication continued for another 40 min. The slurry was then sprayed onto the resin layer, controlling the catalyst loading at 2.0 mg / cm³. 2 Vacuum drying at 80℃ for 4 hours yields the anode CCS.

[0044] Step 4: Assemble the membrane electrode assembly (MEA) The "cathode CCS-AEM membrane" assembly obtained in step 2 and the anode CCS obtained in step 3 are stacked with the anode catalyst layer facing the AEM membrane. The stacks are placed in a hot press and hot-pressed at 100°C and 1 MPa for 3 minutes, then naturally cooled to room temperature to obtain a complete membrane electrode assembly. Its structure is as follows: cathode gas diffusion layer - cathode catalyst layer - AEM membrane - resin layer - anode catalyst layer - anode gas diffusion layer.

[0045] Performance testing: Under 1M KOH and 60℃ conditions, the current density of this MEA at 1.8V is 1.5A / cm². 2 ; at 1A / cm 2 Under constant current operation, after 200 hours of continuous operation, the voltage degradation rate is approximately 45 μV / h.

[0046] Example 2: Step 1: Preparation of cathode CCS A Ni3N / nitrogen-doped carbon catalyst (prepared according to method CN105944746B) was used: nickel nitrate hexahydrate and VXC-72R conductive carbon black were mixed at a 1:1 mass ratio and nitrided at 700℃ for 3 hours in an ammonia atmosphere to obtain a composite catalyst with Ni3N nanoparticles supported on conductive carbon black. 0.12 g of this catalyst was added to 1.06 g of water and 1.94 g of isopropanol (water to isopropanol volume ratio approximately 3:7), and ultrasonically dispersed for 1 hour. Then, 0.30 g of 5 wt% AS-4 anion exchange resin solution was added, and ultrasonic dispersion was continued for 1 hour to obtain a cathode catalyst slurry. The slurry was uniformly sprayed onto one side of carbon paper (General Hydrogen Energy GH-GDB-40) using a spraying method, controlling the catalyst loading to approximately 2.5 mg / cm², and vacuum dried at 60℃ for 6 hours to obtain the cathode CCS.

[0047] Step 2: In-situ preparation of AEM membrane Same as in Example 1, but the doctor blade gap is adjusted to 550 μm and the PAP film thickness is approximately 60 μm.

[0048] Step 3: Prepare the anode CCS (with resin layer) The resin layer is the same as in Example 1. The anode catalyst layer uses CuCo2O4 catalyst: 3 mmol Cu(NO3)2·3H2O and 6 mmol Co(NO3)2·6H2O are dissolved in deionized water, 18 mmol urea is added, and after stirring and dissolving, the mixture is transferred to a reactor and hydrothermally reacted at 120°C for 12 hours. After cooling, the mixture is filtered, washed, and dried to obtain the precursor. The precursor is placed in a muffle furnace and heated to 400°C at a rate of 2°C / min, held for 2 hours, and then naturally cooled to obtain CuCo2O4 nanoparticles. 0.12 g of this CuCo2O4 catalyst is taken, and 1.98 g of isopropanol and 2.02 g of n-propanol are added (isopropanol to n-propanol volume ratio 1:1). The mixture is ultrasonically dispersed for 1 hour, and then 0.8 g of 5 wt% PiperION resin solution is added. The mixture is ultrasonically dispersed for another 40 minutes to obtain the anode catalyst layer slurry. This slurry is sprayed onto nickel foam, with the catalyst loading controlled at approximately 3.5 mg / cm³. 2 Vacuum drying at 80℃ for 4 hours yields the anode CCS.

[0049] Step 4: Assemble the membrane electrode assembly (MEA): Same as in Example 1, with hot pressing conditions of 110°C, 1.2 MPa, and 2.5 minutes.

[0050] Performance testing: Under 1M KOH and 60℃ conditions, the current density of this MEA at 1.8V is 1.2A / cm². 2 ; at 1A / cm 2 Under constant current operation, after 200 hours of continuous operation, the voltage degradation rate is approximately 80 μV / h.

[0051] Example 3: Step 1: Preparation of cathode CCS Hydrophobic treated carbon paper (General Hydrogen Energy GH-GDB-40, 4cm²) was selected. 2 Take 0.016 g of PtRu / C catalyst (Pt:Ru atomic ratio 1:1, total metal content 40 wt%, Johnson Matthey), first add 0.35 g of deionized water to wet the catalyst, then add 0.65 g of isopropanol (water to isopropanol volume ratio approximately 3:7), and ultrasonically disperse for 30 minutes. Then add 0.21 g of 5 wt% AS-4 anion exchange resin solution, and continue ultrasonic dispersion for 40 minutes to obtain the cathode catalyst slurry. The slurry is uniformly sprayed onto one side of carbon paper using a spraying method, with the metal loading controlled at 0.2 mg / cm³. 2 (of which Pt is approximately 0.1 mg / cm³) 2 The cathode CCS was obtained by vacuum drying at 60°C for 6 hours.

[0052] Step 2: In-situ preparation of AEM membrane Same as in Example 1, but the doctor blade gap is adjusted to 400 μm and the PAP film thickness is approximately 45 μm.

[0053] Step 3: Prepare the anode CCS (with resin layer) Resin layer slurry: Take 0.05g of 5wt% AS-4 anion exchange resin solution, add 0.12g of water and 0.83g of isopropanol (water to isopropanol volume ratio 1:9, ultrasonically disperse for 40 minutes, spray onto nickel foam, and control the resin loading to about 0.05mg / cm².

[0054] The anode catalyst layer uses a NiFeCo-based ternary metal oxide catalyst: Nickel, iron, and cobalt nitrates were dissolved in deionized water using a co-precipitation method at a Ni:Fe:Co molar ratio of 6:2:2. NaOH solution was added to adjust the pH to 10-11, and the mixture was stirred and aged for 4 hours. After filtration and washing, the solution was dried at 80℃ and calcined at 450℃ for 2 hours to obtain the NiFeCo ternary metal oxide catalyst. 0.10 g of this catalyst was taken, and 3.5 g of n-propanol was added. The mixture was ultrasonically dispersed for 30 minutes, and then 0.67 g of 5 wt% PiperION resin solution was added. Ultrasonic dispersion was continued for 40 minutes to obtain the anode catalyst layer slurry. This slurry was sprayed onto the resin layer, with the catalyst loading controlled at 2.5 mg / cm³. 2 Vacuum drying at 80℃ for 4 hours yields the anode CCS.

[0055] Step 4: Assemble the membrane electrode assembly (MEA): Same as in Example 1, but with hot pressing conditions of 115°C, 1.5 MPa, and 2 minutes.

[0056] Performance testing: Under 1M KOH and 60℃ conditions, the current density of this MEA at 1.8V is 1.4A / cm². 2 ; at 1A / cm 2 Under constant current operation, after 200 hours of continuous operation, the voltage degradation rate is approximately 60 μV / h.

[0057] Comparative example (conventional CCS method): The same cathode CCS (50wt% Pt / C CCS) and the same anode catalyst slurry (NiFe-LDH) as in Example 1 were used, but without a resin layer. A commercially available PiperION A80 anion exchange membrane (Versogen, 80 μm thick) was used instead of in-situ membrane formation. The cathode CCS, AEM membrane, and anode CCS (without resin layer) were stacked sequentially and hot-pressed at 100°C and 1 MPa for 3 minutes to obtain the membrane electrode assembly (MEA).

[0058] Performance testing: Under 1M KOH and 60℃ conditions, the current density of this MEA at 1.8V is 0.9A / cm². 2 ; at 1A / cm 2 Under constant current operation, the initial voltage was 1.823V, and after 200 hours of operation, the voltage rose to 1.893V, with a voltage degradation rate of approximately 350μV / h.

[0059] The current densities of Examples 1-3 at 1.8V (1.5, 1.2, and 1.4 A / cm², respectively) 2 The values ​​were all significantly higher than those of the control group (0.9 A / cm). 2 Example 1 showed an improvement of approximately 67% compared to the control; at 1A / cm 2 During 200 hours of constant current operation, the voltage degradation rate of Example 1 of this invention was approximately 45 μV / h, which is better than the 350 μV / h of the comparative example.

[0060] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a membrane electrode assembly for anion exchange membrane water electrolysis, characterized in that, Includes the following steps: (1) Preparation of cathode catalyst coating substrate: The hydrogen evolution reaction catalyst, anion exchange resin and solvent are mixed to obtain cathode catalyst slurry, the cathode catalyst slurry is coated on one side of the cathode gas diffusion layer and dried to obtain cathode CCS; (2) In-situ preparation of AEM membrane on cathode CCS: The anion exchange membrane precursor solution is coated on the surface of the catalyst layer of the cathode CCS and cured to obtain an AEM membrane with a dry membrane thickness of 40~80μm, and the AEM membrane is integrally formed with the cathode catalyst layer. (3) Preparation of anode catalyst coating substrate: A resin layer slurry and an anode catalyst layer slurry are sequentially coated on one side of the anode gas diffusion layer and dried to obtain anode CCS; the resin layer slurry is made by mixing anion exchange resin solution and solvent; the anode catalyst layer slurry is made by mixing oxygen evolution reaction catalyst, anion exchange resin and solvent; (4) Assembly: The cathode CCS-AEM membrane assembly obtained in step (2) and the anode CCS obtained in step (3) are stacked with the anode catalyst layer facing the AEM membrane, and hot-pressed to obtain the membrane electrode assembly.

2. The method according to claim 1, characterized in that, In step (1), the hydrogen evolution reaction catalyst is selected from at least one of Pt / C, PtRu / C, and Ni3N / nitrogen-doped carbon; the drying temperature is 50~80℃, the drying time is 4~12 hours, the mass ratio of the hydrogen evolution reaction catalyst to the anion exchange resin is (60~90):(10~40), and the mass ratio of the hydrogen evolution reaction catalyst to the solvent is 1:20~100.

3. The method according to claim 1 or 2, characterized in that, In step (2), the anion exchange membrane precursor solution is a polyarylpiperidine-onium polymer solution with a solid content of 10-20 wt%; the curing temperature is 40-80℃ and the curing time is 0.5-6 hours.

4. The method according to claim 1 or 2, characterized in that, In step (3), the anion exchange resin in the resin layer slurry is a quaternary ammonium salt type resin or a polyarylpiperidine type resin, and the solvent is a mixture of isopropanol and water, with a volume ratio of isopropanol to water of (8~9.5):(0.5~2).

5. The method according to claim 1 or 2, characterized in that, In step (3), the oxygen evolution reaction catalyst is selected from at least one of NiFe-LDH, CuCo2O4, and NiFeCo-based ternary metal oxides; in the anode catalyst slurry, the mass ratio of the oxygen evolution reaction catalyst to the anion exchange resin is (60~90):(10~40), and the mass ratio of the oxygen evolution reaction catalyst to the solvent is 1:20~100.

6. The method according to claim 1 or 5, characterized in that, In step (3), the drying temperature is 70~90℃ and the drying time is 4~8 hours.

7. The method according to claim 1 or 2, characterized in that, In step (4), the hot pressing temperature is 80~130℃, the hot pressing pressure is 0.5~2MPa, and the hot pressing time is 1~5 minutes.

8. The method according to claim 1 or 2, characterized in that, In step (3), the dry film thickness of the resin layer is 1~5μm.

9. The method according to claim 1 or 2, characterized in that, In step (2), the anion exchange membrane precursor solution is coated by a blade coating method, and the wet film thickness is controlled to be 400~550μm by the gap between the blades.

10. The application of the anion exchange membrane electrolysis water electrolysis membrane electrode assembly prepared by the preparation method according to claim 1 in anion exchange membrane water electrolysis hydrogen production.

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