In-situ activation method for preparing a porous anion exchange membrane

Abstract

This application discloses an in-situ activation preparation method for porous anion exchange membranes, relating to the field of anion exchange membrane technology. The preparation method includes: dispersing inorganic template particles in an organic solvent, adding anion exchange membrane matrix material, and mixing to obtain a coating solution containing inorganic template particles; coating the coating solution onto a film-forming substrate and curing it to form a precursor membrane containing inorganic template particles; peeling the precursor membrane from the film-forming substrate; and placing the peeled precursor membrane in a KOH solution for in-situ activation and pore-forming treatment to obtain a porous anion exchange membrane. This application simplifies the preparation process and constructs a continuous and stable OH- membrane by simultaneously etching and pore-forming inorganic template particles and activating the anion exchange membrane in a KOH solution, enabling the porous structure to be generated and stabilized in-situ under a strongly alkaline environment. ‑ The transmission channel also takes into account improving ionic conductivity, reducing membrane swelling rate, and alkali resistance stability.

Description

Technical Field

[0001] This invention relates to the field of anion exchange membrane technology, and specifically to an in-situ activation preparation method for porous anion exchange membranes. Background Technology

[0002] Anion exchange membranes, as key membrane materials in alkaline water electrolysis for hydrogen production, carbon dioxide electrolysis reduction, and other electrochemical energy conversion devices, typically need to simultaneously perform functions such as ion conduction, reactant / product isolation, and maintaining electrode interface stability. Compared to proton exchange membrane systems, anion exchange membranes can operate under alkaline conditions, which helps reduce dependence on noble metal catalysts, thus showing significant application potential in low-cost electrochemical energy devices. With the increasing demands for device current density and energy conversion efficiency, anion exchange membranes not only need to have high OH content... - In addition to conductivity, it also needs to maintain good chemical stability, dimensional stability and mechanical integrity under operating environments such as high temperature and high concentration of alkali.

[0003] In existing technologies, to improve the ion conductivity of anion exchange membranes, methods such as increasing ion exchange capacity, introducing hydrophilic / hydrophobic phase separation structures, constructing microporous structures, or introducing porous channels are commonly used to reduce OH groups. - Migration resistance within the membrane. However, increasing ion exchange capacity often leads to increased membrane water absorption and swelling, thereby weakening the membrane's mechanical strength and dimensional stability. Furthermore, pre-constructed porous membrane materials are prone to uncontrollable changes during subsequent strong alkali activation or long-term alkaline operation, such as swelling of the pore walls, pore size expansion, pore collapse, or pore blockage, resulting in decreased ion transport channel stability. In addition, the preparation of traditional porous anion exchange membranes typically treats porous structure formation and membrane activation as independent steps. For example, the porous structure is first formed through phase inversion, self-assembly, or template etching, followed by post-treatment such as solvent replacement, drying, and alkaline activation. This process is characterized by long flow rates, high energy consumption, heavy burden of solvent or waste liquid treatment, and the pore structure's susceptibility to secondary changes during subsequent activation.

[0004] Therefore, existing technologies still require a method for preparing porous anion exchange membranes that can increase the OH content within the membrane without significantly sacrificing the membrane's structural integrity and dimensional stability. - Improve the continuity and stability of the transport channel, and reduce the step-by-step processing between porous structure construction and membrane activation. Summary of the Invention

[0005] One objective of this invention is to provide an in-situ activation preparation method for porous anion exchange membranes, which solves the technical problems in the prior art where the construction of the porous structure and the membrane activation treatment of porous anion exchange membranes are usually carried out in separate steps, resulting in a complex preparation process, the pore structure being prone to secondary deformation or instability during subsequent strong alkali activation or alkaline operation, and the difficulty in simultaneously achieving high ionic conductivity, low swelling rate and alkali resistance.

[0006] Another objective of this invention is to enable KOH solution to simultaneously complete the etching of inorganic template particles and the activation of anion exchange membrane substrate materials under relatively mild and controllable conditions.

[0007] According to the purpose of this invention, an in-situ activation preparation method for porous anion exchange membranes is provided, comprising: Inorganic template particles are dispersed in an organic solvent and anion exchange membrane matrix material is added. After mixing, a coating solution containing inorganic template particles is obtained. The coating solution is applied to the film-forming substrate and then cured to form a precursor film containing the inorganic template particles. Peel the precursor film from the film-forming substrate; The stripped precursor membrane is placed in a KOH solution for in-situ activation and pore-forming treatment to form a porous structure in situ within the precursor membrane, thereby obtaining the porous anion exchange membrane.

[0008] Optionally, the concentration of the KOH solution is any value between 0.5M and 3M.

[0009] Optionally, the activation temperature of the in-situ activation pore-forming treatment is any value between 30℃ and 90℃, and the treatment time is any value between 1h and 6h.

[0010] Optionally, the coating is performed using a doctor blade, and the thickness of the coating is any value between 10 μm and 100 μm.

[0011] Optionally, the curing process includes drying the film-forming substrate coated with the film-forming liquid at a temperature of 40°C-80°C to form a film.

[0012] Optionally, the organic solvent is N,N-dimethylformamide, the anion exchange membrane substrate material is MTCP, and the mass concentration of MTCP in the membrane scraping solution is any value between 10wt% and 20wt%.

[0013] Optionally, the step of peeling the precursor film from the film-forming substrate further includes: The film-forming substrate on which the precursor membrane is formed is placed in deionized water at 20°C-50°C to allow the precursor membrane to detach from the film-forming substrate.

[0014] Optionally, the inorganic template particles are silica spheres with a particle size of 10 μm.

[0015] Optionally, the coating solution is allowed to stand for 0.5-2 hours to remove bubbles before coating.

[0016] This invention pre-embeds inorganic template particles in the precursor membrane and simultaneously completes template etching and pore creation and anion exchange activation in KOH solution. This transforms the process of porous structure construction and membrane function activation from a step-by-step process to an in-situ integrated process. This simplifies the process flow and forms a stable and continuous ion transport channel adapted to a strongly alkaline environment, thereby improving the ionic conductivity, alkali resistance, dimensional stability, and device interface compatibility of the porous anion exchange membrane.

[0017] Furthermore, by controlling the activation temperature of the in-situ activation pore-forming treatment to 30℃-90℃ and the treatment time to 1h-6h, the present invention enables the KOH solution to simultaneously complete the etching of inorganic template particles and the activation of anion exchange membrane substrate materials under relatively mild and controllable conditions.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic flowchart of an in-situ activation preparation method of a porous anion exchange membrane according to an embodiment of the present invention; Figure 2 This is a photograph of the porous anion exchange membrane prepared according to Example 1 of the present invention. Figure 3 This is a scanning electron microscope (SEM) image of the porous anion exchange membrane prepared according to Example 1 of the present invention. Figure 4 This is a scanning electron microscope cross-sectional image of the porous anion exchange membrane prepared according to Example 1 of the present invention; Figure 5 This is an ionic conductivity diagram of the porous anion exchange membranes prepared according to Example 1 and Comparative Example 1 of the present invention. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0022] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] Figure 1 This is a schematic flowchart of an in-situ activation preparation method of a porous anion exchange membrane according to an embodiment of the present invention. Figure 2 This is a physical image of the porous anion exchange membrane prepared according to Example 1 of the present invention.

[0025] like Figure 1 As shown, this invention provides an in-situ activation preparation method for porous anion exchange membranes, comprising: Step S100: Disperse the inorganic template particles in an organic solvent and add anion exchange membrane matrix material. After mixing, a coating solution containing inorganic template particles is obtained. Step S200: Apply the film coating solution to the film-forming substrate and perform a curing treatment to form a precursor film containing inorganic template particles; Step S300: Peel the precursor membrane from the film-forming substrate; Step S400: The stripped precursor membrane is placed in KOH solution for in-situ activation and pore-forming treatment to form a porous structure in situ within the precursor membrane, thereby obtaining a porous anion exchange membrane (refer to...). Figure 2 ).

[0026] This embodiment provides an in-situ activation preparation method for porous anion exchange membranes. First, inorganic template particles are dispersed in an organic solvent, and anion exchange membrane substrate material is added. After mixing, a coating solution containing inorganic template particles is obtained, allowing the inorganic template particles to be uniformly dispersed in the film-forming system and serving as sacrificial templates for subsequent pore formation. Next, the coating solution is coated onto the film-forming substrate and cured to form a precursor membrane containing inorganic template particles, allowing the inorganic template particles to form spatial occupancy structures within the precursor membrane. Then, the precursor membrane is peeled off from the film-forming substrate to obtain a template-containing precursor membrane that can be independently processed. Finally, the peeled precursor membrane is placed in a KOH solution for in-situ activation and pore formation treatment. The KOH solution, on the one hand, etches and removes the inorganic template particles within the precursor membrane, forming porous structures in situ at the original occupancy sites of the inorganic template particles; on the other hand, it alkalizes and activates the anion exchange membrane substrate material, allowing exchangeable anions within the membrane to be converted by the OH groups. - The template is replaced, thus simultaneously completing template etching and pore creation and anion exchange activation to obtain a porous anion exchange membrane.

[0027] In this embodiment, by pre-embedding inorganic template particles in the precursor membrane and simultaneously completing template etching and pore creation and anion exchange activation in KOH solution, the construction of porous structure and activation of membrane function are transformed from stepwise processing to in-situ integrated processing. This simplifies the process flow while forming a stable and continuous ion transport channel adapted to a strong alkaline environment, thereby improving the ionic conductivity, alkali resistance, dimensional stability and device interface compatibility of the porous anion exchange membrane.

[0028] In steps S100 and S200, the inorganic template particles are not simply used as fillers, but rather as sacrificial site-occupying phases that can be selectively removed by the subsequent KOH solution. By pre-dispersing the inorganic template particles uniformly in the film-forming system of the anion exchange membrane matrix material and co-curing them into the precursor membrane along with the coating solution, the inorganic template particles form a predetermined spatial distribution in both the thickness and surface directions of the membrane. Thus, before entering the KOH solution, the precursor membrane has already formed a composite structure of a continuous membrane matrix phase and a dispersed template particle phase. After the template particles are subsequently etched away, their original site-occupying regions can be transformed into a porous structure, thereby allowing the pore position, pore size, and pore density to be pre-controlled by the particle size, dispersion state, and amount of the inorganic template particles.

[0029] In step S400, the KOH solution simultaneously serves as both a template etching medium and a film activation medium. First, the KOH solution can etch or dissolve the inorganic template particles within the precursor film, transforming the area where the template particles are located into channels in situ. Second, the OH groups in the KOH solution... - It can penetrate into the membrane substrate and undergo ion exchange with exchangeable anions in the anion exchange membrane substrate material, thus transforming the precursor membrane into one with OH groups. - Anion exchange membranes with high conductivity. This is due to the pore formation process and the interaction with OH groups. - The activation process is carried out simultaneously in the same alkaline environment. Therefore, the pore walls and ion exchange sites formed can be stabilized simultaneously under strong alkaline conditions. This is beneficial for constructing continuous, stable ion transport channels that are adapted to the alkaline working environment, and avoids the problems of secondary deformation, collapse or discontinuity of transport channels that may occur in traditional stepwise pore building and subsequent strong alkaline activation.

[0030] In a further embodiment, the concentration of the KOH solution is any value between 0.5M and 3M, that is, the concentration of the KOH solution can be 0.5M, 1M, 1.5M, 2M, 2.5M, or 3M, or any other value between 0.5M and 3M. In this embodiment, by controlling the concentration of the KOH solution within the range of 0.5M-3M, the KOH solution can simultaneously possess sufficient etching capability for inorganic template particles and anion exchange activation capability, thereby completing template removal, in-situ formation of pore structure, and exchangeable anion transfer to OH groups within the membrane in the same processing step. - The conversion process is complex. When the KOH concentration is too low, the etching rate of inorganic template particles is slow, which can easily lead to insufficient template removal, incomplete channel formation, and insufficient film activation, thus affecting the conversion of KOH. - The continuity of the transport channel is affected. When the KOH concentration is too high, the strong alkali effect is too strong, which may lead to excessive swelling of the membrane substrate, damage to the pore wall structure, or uncontrolled expansion of the pore size, thereby reducing the mechanical integrity and dimensional stability of the membrane.

[0031] In a further embodiment, the activation temperature for the in-situ activation pore-forming treatment is any value between 30℃ and 90℃, and the treatment time is any value between 1h and 6h. That is, the activation temperature for the in-situ activation pore-forming treatment can be 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, or 90℃, or any other value between 30℃ and 90℃. By controlling the activation temperature of the in-situ activation pore-forming treatment within the range of 30℃-90℃ and the treatment time within the range of 1h-6h, the KOH solution can simultaneously complete the etching of inorganic template particles and the activation of the anion exchange membrane substrate material under relatively mild and controllable conditions. On the one hand, appropriately increasing the activation temperature and extending the treatment time is beneficial for the KOH solution to fully penetrate into the precursor membrane, accelerate the etching and removal of inorganic template particles, and promote the OH... -Ion exchange with exchangeable anions within the membrane transforms the precursor membrane into one with OH groups. - The porous anion exchange membrane has high conductivity; on the other hand, the temperature and time range can avoid excessive swelling of the membrane substrate, damage to the pore walls, uncontrolled expansion of pore size, or decline in the mechanical properties of the membrane caused by excessively harsh alkaline treatment, thereby ensuring the integrity of the porous structure and the main membrane structure.

[0032] Furthermore, a combination of activation temperature of 30℃-90℃ and treatment time of 1h-6h can achieve a balance between sufficient template removal and membrane structure stability. When the activation temperature is too low or the treatment time is too short, the inorganic template particles may not be sufficiently etched, the membrane pore structure may not be fully formed, and the anion exchange activation degree may be insufficient, leading to OH... - The transport channels are discontinuous, and the improvement in ionic conductivity is limited. When the activation temperature is too high or the processing time is too long, although it is beneficial to template removal and ion exchange, it may also exacerbate the swelling or structural relaxation of the membrane substrate in a strongly alkaline environment, resulting in pore collapse, pore wall deformation, or decreased dimensional stability.

[0033] In a further embodiment, coating is performed using a doctor blade, with the doctor blade applying a coating thickness of any value between 10 μm and 100 μm. Specifically, the coating thickness can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm, or any other value within the 10 μm-100 μm range. By using a doctor blade for coating and controlling the coating thickness within the 10 μm-100 μm range, the spreading thickness of the coating solution on the film-forming substrate can be adjusted in a mechanically controllable manner. This results in a relatively uniform distribution of inorganic template particles and anion exchange membrane matrix materials in the membrane surface direction, thereby improving the thickness consistency and film formation repeatability of the precursor membrane. Compared to methods such as drop coating and casting, blade coating is more conducive to obtaining precursor films with adjustable thickness and smooth surface, providing a stable foundation for the uniform penetration of KOH solution into the film body and the simultaneous completion of template etching and pore creation and film activation.

[0034] Furthermore, limiting the film thickness to the range of 10μm-100μm achieves a balance between membrane mechanical integrity, ion transport resistance, and pore structure stability. When the film thickness is too low, the precursor membrane is too thin, making it prone to cracking, curling, or forming through-hole defects during peeling or KOH activation pore formation, affecting the membrane's barrier properties and operational stability. When the film thickness is too high, the KOH solution cannot uniformly penetrate the membrane within a short time, easily leading to insufficient template etching and anion exchange activation. Additionally, increasing the film thickness prolongs the OH... - Transport path, increasing ion transport resistance.

[0035] In a further embodiment, the curing process includes drying the film-forming substrate coated with the coating solution at a temperature of 40°C-80°C to form a film. Specifically, the curing temperature can be 40°C, 50°C, 60°C, 70°C, or 80°C, or any other value within the 40°C-80°C range. By drying the film-forming substrate coated with the coating solution at 40°C-80°C, the organic solvent can be gradually evaporated in a relatively mild and controllable manner, allowing the anion exchange membrane substrate material to continuously cure on the surface of the film-forming substrate and stably fixing the inorganic template particles inside the membrane substrate. This temperature range avoids the problems of insufficient solvent evaporation, excessively long film-forming time, and excessive residual solvent in the membrane layer caused by excessively low temperatures, while also avoiding defects such as wrinkling, cracking, porosity, uneven thickness, or local migration of inorganic template particles caused by excessively high temperatures due to rapid solvent evaporation. This improves the continuity, smoothness, and structural integrity of the precursor membrane.

[0036] In a further embodiment, the organic solvent is N,N-dimethylformamide, the anion exchange membrane substrate material is MTCP, and the mass concentration of MTCP in the scraping solution is any value between 10wt% and 20wt%, that is, the mass concentration of MTCP in the scraping solution can be 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, or 20wt%, or any other value between 10wt% and 20wt%. By selecting N,N-dimethylformamide as the organic solvent and MTCP as the anion exchange membrane substrate material, MTCP can be fully dissolved in the film-forming system to form a uniform and stable scraping solution, thereby ensuring that the inorganic template particles can be more uniformly dispersed in the anion exchange membrane substrate material, avoiding uneven membrane thickness, template particle agglomeration, or uneven pore structure distribution caused by insufficient dissolution or local gelation of the anion exchange membrane substrate material. Here, MTCP, as the host material of the membrane, can provide the exchangeable ion sites required for anion conduction and has good alkali resistance. In the subsequent KOH in-situ activation and pore-forming process, it can synergistically construct a stable OH group with the porous structure formed by template etching. - This improves the ion conduction performance of porous anion exchange membranes and their structural stability under alkaline conditions by creating transport channels.

[0037] Furthermore, controlling the MTCP concentration in the coating solution within the range of 10wt%-20wt% achieves a balance between coating solution flowability, film formation continuity, and membrane mechanical integrity. When the MTCP concentration is too low, the solid content of the coating solution is insufficient, leading to an excessively thin membrane with insufficient mechanical strength after curing. Additionally, the inorganic template particles are difficult to effectively coat the continuous membrane matrix, potentially resulting in excessively interconnected defect pores or localized damage after subsequent KOH etching. Conversely, when the MTCP concentration is too high, the viscosity of the coating solution is too high, easily causing decreased coating leveling, uneven template particle dispersion, and increased film thickness fluctuations, thus affecting the uniformity of the pore structure. By limiting the MTCP concentration to 10wt%-20wt%, a coating solution with suitable viscosity and solid content can be formed, enabling the precursor membrane to possess good film-forming properties, structural integrity, and template distribution uniformity. This provides a stable foundation for subsequent KOH simultaneous etching for pore formation and anion exchange activation, thereby obtaining a porous anion exchange membrane with uniform pore structure, continuous ion transport channels, and good dimensional stability.

[0038] In a further embodiment, step S300 further includes: The film-forming substrate with the precursor membrane is placed in deionized water at 20℃-60℃ to allow the precursor membrane to detach from the film-forming substrate.

[0039] In this embodiment, the film-forming substrate with the precursor membrane is placed in deionized water at 20°C-50°C. This allows the deionized water to enter the interfacial region between the precursor membrane and the film-forming substrate, reducing the interfacial adhesion between them. This causes the precursor membrane to detach naturally or with assisted detachment from the film-forming substrate, resulting in a freely transferable precursor membrane containing inorganic template particles. The film-forming substrate can be a glass plate. The 20°C-60°C deionized water promotes separation between the membrane and the substrate interface without damaging the anion exchange membrane matrix material and the distribution of inorganic template particles in the precursor membrane. The temperature of the deionized water can be 20°C, 30°C, 40°C, or 50°C, or any other value within the 20°C-50°C range.

[0040] In this embodiment, by placing the film-forming substrate with the precursor film on it in deionized water at 20℃-50℃ for demolding, the wetting, penetration, and heat-assisted peeling effects of warm water at the precursor film / film-forming substrate interface are utilized. This allows the precursor film to detach from the film-forming substrate without the need for strong mechanical peeling or organic solvent demolding, thereby reducing the risk of precursor film tearing, curling, local damage, or disturbance of template particle distribution, and maintaining the structural integrity and thickness uniformity of the precursor film. Simultaneously, this demolding method avoids the introduction of additional organic demolding agents, and the process is gentle and clean, which facilitates the uniform entry of KOH solution into the film interior during subsequent KOH in-situ activation and pore-forming treatment, thereby improving the uniformity of template etching and film activation.

[0041] In a further embodiment, the inorganic template particles are silica spheres with a particle size of 10 μm.

[0042] In a further embodiment, the coating solution is allowed to stand for 0.5-2 hours to remove bubbles before coating. The standing time for defoaming can be 0.5 hours, 1 hour, 1.5 hours, or 2 hours, or any other value within the 0.5-2 hour range. By allowing the coating solution to stand for 0.5-2 hours before coating, bubbles introduced during mixing, ultrasonication, or stirring can be fully released and float to the surface. This reduces defects such as pinholes, voids, streaks, localized weak areas, or uneven film thickness caused by residual bubbles during coating, thereby improving the continuity, density, and thickness uniformity of the precursor film. Simultaneously, controlling the standing time within the 0.5-2 hour range ensures sufficient bubble release while avoiding excessive standing time that could lead to sedimentation, agglomeration, or uneven distribution of inorganic template particles in the coating solution. This maintains good dispersion of the inorganic template particles in the film-forming system, providing a stable foundation for subsequent in-situ KOH etching to form a uniform pore structure.

[0043] Furthermore, since the porous structure in this embodiment is formed in situ by etching the inorganic template particles in the precursor film with KOH solution, the distribution of bubbles and inorganic template particles in the film scraping solution will directly affect the uniformity of the subsequent pore structure.

[0044] The technical solution of this application will be further described below with reference to specific embodiments.

[0045] Example 1

[0046] 10 μm silica spheres were ultrasonically dispersed in N,N-dimethylformamide, and MTCP was added and ultrasonically dissolved to prepare a 15 wt% MTCP coating solution. After the coating solution was allowed to stand for 1 hour to remove bubbles, it was coated onto a glass plate with a coating thickness of 50 μm using a coating blade. The glass plate coated with the coating solution was dried at 60 °C to form a precursor film containing silica spheres. Subsequently, the glass plate was placed in deionized water at 20 °C to allow the precursor film to detach automatically from the glass plate. The detached precursor film was then placed in a 1 M KOH solution and treated at 80 °C for 5 hours to etch and remove the silica spheres with KOH, while simultaneously causing the MTCP film to undergo OH- oxidation. - After activation, the membrane was removed, washed multiple times with deionized water, and stored in deionized water to obtain a porous anion exchange membrane. The test temperature was 30℃.

[0047] Example 2

[0048] The only difference between Example 2 and Example 1 is that the particle size of the silica spheres is 1 μm.

[0049] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that no silica balls were added.

[0050] Figure 3 This is a scanning electron microscope (SEM) image of the porous anion exchange membrane prepared according to Example 1 of the present invention. Figure 4 This is a scanning electron microscope cross-sectional image of the porous anion exchange membrane prepared according to Example 1 of the present invention. Figure 5 This is an ionic conductivity diagram of the porous anion exchange membranes prepared according to Example 1 and Comparative Example 1 of the present invention. First, the porous ion exchange membrane prepared in Example 1 was characterized by scanning electron microscopy, and the results are as follows: Figure 3 and Figure 4 The characterization results.

[0051] like Figure 3 He Ru Figure 4 As shown, the porous anion exchange membrane prepared in Example 1 exhibits a relatively uniform and continuous porous structure on both the surface and cross-sectional directions. This indicates that the silica spheres can be pre-fixed in the precursor membrane as sacrificial templates in the coating solution and then etched away during subsequent KOH solution treatment, thereby forming pores in situ on the membrane surface and inside the membrane. This result demonstrates that the porous structure formed in this application is a controllable pore structure created by silica sphere template occupancy and KOH etching removal. Furthermore, the cross-sectional morphology further illustrates that the KOH solution can penetrate the interior of the precursor membrane, not just etch or activate the membrane surface, transforming the occupancy area of ​​the inorganic template particles in the thickness direction into a continuous or semi-continuous ion transport path.

[0052] Next, the water absorption rate, swelling rate and conductivity of the porous anion exchange membranes in Examples 1-2 and Comparative Examples 1-2 were tested, and the test results are shown in Table 1.

[0053] Table 1. Performance test results of porous anion exchange membranes in Examples 1-2 and Comparative Examples 1-2 As shown in Table 1 and Figure 5 As shown, in Example 1, after adding 10 μm silica spheres and undergoing in-situ activation and pore-forming treatment with KOH, the water absorption rate was 37.0%, the swelling rate was 9.2%, and the conductivity was 182.9. In contrast, in Comparative Example 1 without silica spheres, the water absorption rate was 44.3%, the swelling rate was 10.2%, and the conductivity was only 101.9. This indicates that, compared to the MTCP membrane activated solely with KOH, Example 1 does not improve ion conductivity by increasing water absorption or membrane swelling. Instead, it significantly improves conductivity while reducing both water absorption and swelling rates. This demonstrates that the porous structure formed by the silica spheres after KOH etching can facilitate ion conduction. -It provides a more efficient transport channel. In Example 2, after using 1μm silica spheres, the conductivity was 153.8, which was still significantly higher than that of Comparative Example 1, indicating that in-situ pore formation using silica templates generally improves ion conduction performance; however, its conductivity was lower than that of Example 1, indicating that the template particle size affects the pore structure size and transport channel connectivity. Under the experimental conditions of this group, the pore structure formed by 10μm silica spheres is more conducive to constructing continuous and efficient OH groups. - Transmission path. Further integration Figure 5 It can be seen that the ionic conductivity of Example 1 at different test temperatures is higher than that of Comparative Example 1 without silica balls, indicating that although increasing the temperature can increase the ionic conductivity of OH-, it can also increase the ionic conductivity of OH-. - While the migration capability is significant, the advantage of Example 1 primarily stems from the porous transport structure formed by in-situ activation and pore creation, rather than simply testing temperature changes or KOH activation itself.

[0054] In summary, this application utilizes silica sphere templates for site placement, simultaneous KOH etching for hole creation, and OH... - The in-situ integrated activation process enables the formation of stable and continuous OH groups within the membrane. - The transport channel distinguishes it from ordinary KOH activated membranes without template particles, and achieves a synergistic improvement in ion conduction performance and dimensional stability.

[0055] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0056] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for in-situ activation of a porous anion exchange membrane, characterized by, include: Inorganic template particles are dispersed in an organic solvent and anion exchange membrane matrix material is added. After mixing, a coating solution containing inorganic template particles is obtained. The coating solution is applied to the film-forming substrate and then cured to form a precursor film containing the inorganic template particles. Peel the precursor film from the film-forming substrate; The stripped precursor membrane was placed in a KOH solution for in-situ activation and pore-forming treatment to form a porous structure in situ within the membrane, thereby obtaining the porous anion exchange membrane.

2. The in-situ activation preparation method of the porous anion exchange membrane according to claim 1, characterized in that, The concentration of the KOH solution is any value between 0.5M and 3M.

3. The in-situ activation preparation method of the porous anion exchange membrane according to claim 2, characterized in that, The activation temperature for the in-situ activation pore-forming treatment is any value between 30℃ and 90℃, and the treatment time is any value between 1h and 6h.

4. The in-situ activation preparation method of the porous anion exchange membrane according to claim 3, characterized in that, The coating is performed using a doctor blade, and the thickness of the coating is any value between 10μm and 100μm.

5. The in-situ activation preparation method of the porous anion exchange membrane according to claim 4, characterized in that, The curing process includes drying the film-forming substrate coated with the film-forming liquid at a temperature of 40°C-80°C to form a film.

6. The in-situ activation preparation method of the porous anion exchange membrane according to claim 5, characterized in that, The organic solvent is N,N-dimethylformamide, the anion exchange membrane substrate material is MTCP, and the mass concentration of MTCP in the membrane scraping solution is any value between 10wt% and 20wt%.

7. The method according to any one of claims 1 to 6, wherein the method is characterized by, The step of peeling the precursor membrane from the film-forming substrate further includes: The film-forming substrate on which the precursor membrane is formed is placed in deionized water at 20°C-50°C to allow the precursor membrane to detach from the film-forming substrate.

8. The in-situ activation preparation method of the porous anion exchange membrane according to claim 7, characterized in that, The inorganic template particles are silica spheres with a particle size of 10 μm.

9. The in-situ activation preparation method of the porous anion exchange membrane according to claim 8, characterized in that, Before coating, the coating solution is allowed to stand for 0.5-2 hours to remove bubbles.

Images