Isolating membrane, preparation method thereof and alkaline electrolysis device

Abstract

The embodiment of the invention relates to the field of electrolysis, and provides an isolating membrane, a preparation method thereof and an alkaline electrolysis device. The isolating membrane comprises a supporting layer, a functional layer is arranged on the surface of the supporting layer, and the functional layer is partially embedded into the supporting layer; the porosity of the functional layer is 53%-65%, the average pore size of pores in the functional layer is 50-110 nm, and the average pore size of pores in the supporting layer is larger than the average pore size of pores in the functional layer; the functional layer comprises an inorganic hydrophilic filler and a polymer matrix, and the D50 particle size of the inorganic hydrophilic filler is 0.3-1.5 [mu] m. The isolating membrane in the embodiment of the invention at least has good gas barrier property and good ionic conductivity at the same time, so that the alkaline isolating membrane not only has good safety performance, but also is relatively low in energy consumption.

Description

Technical Field

[0001] This application relates to the field of electrolysis, and particularly to a separator membrane and its preparation method, and an alkaline electrolysis apparatus. Background Technology

[0002] In alkaline water electrolysis hydrogen production systems, the separator is one of the core components. Its main function is to allow hydroxide ions (OH-) to pass through the separator. - The alkaline electrolysis device must efficiently conduct electricity for the electrolysis reaction while effectively preventing the mixing of hydrogen and oxygen to ensure safe system operation and product purity. A higher bubble point of the separator indicates better gas barrier performance, resulting in better safety of the alkaline electrolysis unit. Conversely, a lower sheet resistivity indicates higher ionic conductivity, leading to lower energy consumption.

[0003] However, current separators struggle to achieve both good gas barrier properties and good ionic conductivity. Summary of the Invention

[0004] This application provides a separator membrane and its preparation method, as well as an alkaline electrolysis device. The separator membrane in this application embodiment can simultaneously have good gas barrier performance and good ionic conductivity, so that the alkaline separator membrane has both good safety performance and low energy consumption.

[0005] According to some embodiments of this application, a first aspect of this application provides a separating membrane, including a support layer, a functional layer disposed on the surface of the support layer, and the functional layer being partially embedded in the support layer; the porosity of the functional layer is 53%~65%, the average pore size of the pores in the functional layer is 50nm~110nm, and the average pore size of the pores in the support layer is larger than the average pore size of the pores in the functional layer; the functional layer includes an inorganic hydrophilic filler and a polymer matrix, and the D50 particle size of the inorganic hydrophilic filler is 0.3μm~1.5μm.

[0006] In some embodiments of this application, the inorganic hydrophilic filler includes at least one of ZrO2, TiO2, or CeO2.

[0007] In some embodiments of this application, the polymer matrix includes at least one of polystyrene, polyphenylene sulfone, polyether sulfone, or bisphenol A type polysulfone.

[0008] In some embodiments of this application, the mass ratio of inorganic hydrophilic filler to polymer matrix in the functional layer is 70:30 to 90:10.

[0009] In some embodiments of this application, the thickness of the separator is 200 μm to 550 μm.

[0010] In some embodiments of this application, the bubble point of the separator is 8 bar to 22 bar, and the sheet resistance of the separator is 0.16 Ω / cm. 2 ~0.23Ω / cm 2 .

[0011] According to some embodiments of this application, a second aspect of this application provides a method for preparing a separating membrane, comprising the following steps: mixing an inorganic hydrophilic filler, a polymer matrix, and an organic solvent to form a slurry, wherein the D50 particle size of the inorganic hydrophilic filler is 0.3 μm to 1.5 μm, and the viscosity of the slurry is 1,000,000 mPa·s to 2,000,000 mPa·s; coating the slurry onto the surface of a support layer, thereby impregnating the support layer; and performing phase separation of the slurry in a coagulation bath to form a layer, wherein the temperature during phase separation is -5°C to 30°C.

[0012] In some embodiments of this application, the organic solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N-ethylpyrrolidone, dimethyl sulfoxide, or tetramethyl sulfoxide.

[0013] In some embodiments of this application, the coagulation bath includes at least one of water, methanol, ethanol, or isopropanol.

[0014] According to some embodiments of this application, a third aspect of this application provides an alkaline electrolysis device, including an electrolysis chamber, an anode and a cathode disposed within the electrolysis chamber, and a separating membrane disposed between the anode and the cathode, the separating membrane being used to isolate the anode and the cathode; the separating membrane is the separating membrane described above, or the separating membrane is prepared by the method described above for preparing the separating membrane.

[0015] The technical solution provided in this application has at least the following advantages: Compared to existing technologies, the separator in this embodiment does not contain any additional additives and only has two layers: a functional layer and a support layer. Therefore, the structure and preparation process are simple, internal peeling is less likely to occur, and the entire separator is relatively stable. Moreover, in this embodiment, since the average pore size and porosity of the functional layer are within a suitable range, the pores in the functional layer are honeycomb-shaped rather than finger-shaped, which is beneficial to improving the gas barrier performance of the separator. In addition, the D50 particle size of the inorganic hydrophilic filler in the functional layer is also within a suitable range. This not only ensures that the porosity and average pore size in the functional layer can be maintained within the above range, but also forms a continuous hydrophilic surface and interconnected microporous channels throughout the functional layer, giving the separator excellent ionic conductivity. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a SEM image of the cross-section of the separator provided in Embodiment 1 of this application. Detailed Implementation

[0018] As the background technology shows, existing separator membranes struggle to simultaneously achieve both good gas barrier properties and good ionic conductivity. Specifically, the inventors have discovered that the mainstream approach in the industry for improving the bubble point of separator membranes is a composite modification approach of "polymer crosslinking + hydrophilic agent addition." This means that existing solutions are all "post-hoc repair" improvements, using the introduction of second or third components to compensate for the shortcomings of a single material. However, this approach struggles to overcome the constraints between gas barrier performance and ionic conductivity, and it also easily leads to other problems such as complex processes, increased costs, and questionable long-term reliability.

[0019] For example, patent CN117431587A discloses a composite membrane and its preparation method and uses. Since carbon nanotubes are used as additives in the composite membrane and combined with the matrix, its long-term stability may be insufficient. Moreover, carbon nanotubes are conductive media, which pose certain safety risks during operation.

[0020] For example, patent CN117512693A discloses a composite membrane for alkaline water electrolysis hydrogen production with a superhydrophilic surface and an overall cross-linked structure. The bubble point is raised to about 6 bar by the overall cross-linking method, and the degree of cross-linking is 3%-10%. Although the safety performance of the electrolyzer is improved, the presence of a 3-11 μm superhydrophilic coating significantly increases the overall thickness of the membrane and the ion transport path, resulting in poor conductivity, low stability, and a more complex process.

[0021] The separator provided in this application embodiment, by adjusting the parameters of the functional layer, can achieve both good gas barrier performance and good ionic conductivity. Furthermore, the separator in this application embodiment has a simple structure, a relatively simple preparation method, and good adhesion, making it less prone to interlayer delamination.

[0022] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).

[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] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0025] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "below," or "bottom" of other elements or features will be oriented "above" or "top" of other elements or features. Therefore, the term "below" may cover both above and below orientation depending on the context in which the term is used, which will be obvious to those skilled in the art. Materials may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0026] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0027] In the description of embodiments of this application, the terms "about," "approximately," "roughly," or "about" for referring to a specific parameter include numerical values, and those skilled in the art will understand that the deviation from the numerical value is within the acceptable tolerance of the specific parameter. For example, "about" or "about" for a numerical value may include additional numerical values ​​that are in the range of 90.0% to 110.0% of the numerical value, such as in the range of 95.0% to 105.0%, 97.5% to 102.5%, 99.0% to 101.0%, 99.5% to 100.5%, or 99.9% to 100.1%.

[0028] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. Furthermore, when describing a component as "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0029] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. The formation or provision of a second component above or on a first component, or on the surface of a first component, or on one side of a first component, may include embodiments where the first and second components are in direct contact, and may also include embodiments where an additional component may be present between the first and second components, thereby preventing direct contact between the first and second components. For simplicity and clarity, various components may be drawn at different scales. In the drawings, some layers / components may be omitted for simplicity. Unless otherwise specified, the formation or provision of a second component on the surface of a first component refers to direct contact between the first and second components. The term "component" may refer to a layer, film, region, portion, structure, etc.

[0030] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0031] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0032] This application provides an isolation membrane, including a support layer, a functional layer disposed on the surface of the support layer, and the functional layer being partially embedded in the support layer; the porosity of the functional layer is 53%~65%, the average pore size of the functional layer is 50nm~110nm, and the average pore size of the support layer is larger than the average pore size of the functional layer; the functional layer includes an inorganic hydrophilic filler and a polymer matrix, and the D50 particle size of the inorganic hydrophilic filler is 0.3μm~1.5μm.

[0033] In this embodiment, the functional layer has a high porosity, ranging from 53% to 65%, and a small average pore size, typically in the range of 50 nm to 110 nm. Therefore, the pores throughout the entire functional layer exhibit a uniform and fine "honeycomb" structure (e.g., Figure 1 As shown in the figure, compared to the existing "finger-shaped pores," the honeycomb pores in the functional layer of this application embodiment enable the separator to have good gas barrier performance; in addition, the polymer matrix in the functional layer can act as a binder to provide a connection between the support layer and the inorganic hydrophilic filler, and can also provide attachment sites for the inorganic hydrophilic filler; the inorganic hydrophilic filler can provide OH... -The inorganic hydrophilic filler has an ion conduction channel, and because its D50 particle size is in the range of 0.3μm to 1.5μm, this not only ensures that the porosity and average pore size in the functional layer are maintained within this range, but also forms a continuous hydrophilic surface and interconnected microporous channels throughout the entire functional layer, resulting in excellent ionic conductivity of the membrane. If the average pore size in the functional layer is greater than 1.5μm, the bubble point will decrease significantly; if it is less than 0.3μm, the bubble point will increase but the pore size will decrease, leading to an increase in sheet resistance and a significant increase in slurry viscosity, making it difficult to control the film formation state. If the porosity of the functional layer is greater than 65%, the bubble point will be lower and the mechanical strength will decrease; if it is less than 53%, the sheet resistance will be higher and the electrical properties will relatively decrease. The support layer in the separator provides mechanical support for the functional layer, giving the functional layer and the entire separator good mechanical strength. Therefore, the average pore size in the support layer is larger than that in the functional layer. In addition, since the functional layer is partially embedded in the support layer, there is also a good ion transport channel between the functional layer and the support layer, and the functional layer and the support layer are not easily separated. This ensures that the separator has good ionic conductivity and high stability.

[0034] It should be noted that in the embodiments of this application, "particle size" is equivalent particle size, which means that when a certain physical property of a non-spherical particle is the same as or similar to that of a homogeneous spherical particle, the diameter of the spherical particle is used to represent the diameter of the actual particle; "D50 particle size" refers to the particle size value corresponding to when the cumulative particle size distribution of the sample reaches 50%, indicating that particles with a particle size greater than and less than this value each account for 50%.

[0035] In some embodiments of this application, the inorganic hydrophilic filler in the functional layer may include, but is not limited to, at least one of ZrO2, TiO2, or CeO2. Additionally, in some embodiments of this application, the polymer matrix in the functional layer typically includes at least one of polystyrene (PS) or a polysulfone polymer matrix, wherein the polysulfone polymer matrix includes at least one of polyphenylene sulfone resins (PPSU), polyethersulfone (PES), or bisphenol A type polysulfone (PSU). Furthermore, in some embodiments of this application, the mass ratio of inorganic hydrophilic filler to polymer matrix is ​​typically set to 70:30 to 90:10, allowing for a more uniform distribution of the inorganic hydrophilic filler in the functional layer and more unobstructed ion channels, thereby improving the ion transport performance of the functional layer and the separating membrane.

[0036] This application does not impose any particular limitation on the average pore size of the pores in the support layer, as long as it is larger than the average pore size of the pores in the functional layer and meets the purpose of this application. As an example, in some embodiments of this application, the average pore size of the pores in the support layer is 150 μm to 550 μm. Furthermore, this application does not impose any particular requirements on the material of the support layer, as long as it meets the purpose of this application. The support layer can be a single-layer structure or a multi-layer composite structure; its material can be a polymer or a mixture of polymer and inorganic modifier. For example, the material of the support layer may include at least one of PPS (Polyphenylene sulfide), PEEK (Polyetheretherketone), and PTFE (Polytetrafluoroethylene).

[0037] This application does not have specific requirements for the total thickness of the separator, as long as it meets the purpose of this application. For example, the total thickness of the separator can be 200μm to 550μm, so that the resistive loss and mechanical strength of the separator can be well balanced. As an example, in the specific embodiments of this application, a separator with a thickness of 500μm is used uniformly.

[0038] The separator in this application embodiment has both good gas barrier properties and good ionic conductivity. Specifically, in some embodiments of this application, the bubble point of the separator can reach 8 bar to 22 bar, while the surface resistivity is 0.16 Ω / cm. 2 ~0.23Ω / cm 2 .

[0039] Accordingly, this application also provides a method for preparing a separator membrane, specifically including the following steps: S100. Preparation of slurry: Mix inorganic hydrophilic filler, polymer matrix and organic solvent to form slurry with a viscosity of 1,000,000 mPa·s to 2,000,000 mPa·s.

[0040] In this step, the D50 particle size of the inorganic hydrophilic filler is typically controlled within the range of 0.3 μm to 1.5 μm, which is beneficial for generating a slurry with the aforementioned viscosity. If the D50 particle size is too small, the slurry viscosity will be high and difficult to control; if the D50 particle size is too large, the slurry viscosity will be too low. Of course, the viscosity of the slurry is also related to the ratio of organic solvent to solute (mainly inorganic hydrophilic filler and polymer matrix), which will not be elaborated here, as long as the viscosity of the slurry is kept within the aforementioned range. This is because the inventors discovered that when the slurry is within the aforementioned range, the temperature during subsequent phase separation allows the functional layer formed after phase separation to have a honeycomb-like pore structure. At this time, the pore size in the functional layer is 50 nm to 110 nm, and the porosity of the functional layer is 53% to 65%.

[0041] This application does not have specific requirements regarding the type of organic solvent, as long as it can disperse the solute relatively uniformly. For example, the organic solvent may include, but is not limited to, at least one of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-ethylpyrrolidone, dimethyl sulfoxide, or tetramethyl sulfoxide. Furthermore, after dispersing the inorganic hydrophilic filler and polymer matrix in the solvent, this step involves high-speed stirring and degassing to ensure a relatively uniform and stable slurry.

[0042] S200, Casting and Film Forming: This step typically involves using a doctor blade to evenly coat the slurry onto both sides of the support layer, allowing the slurry to penetrate the support layer. The support layer is centered, and the inorganic hydrophilic layers on both sides enhance the electrical properties. During subsequent phase separation and curing of the slurry, the functional layer can be partially embedded into the support layer.

[0043] S300, Phase Separation: The support layer carrying the slurry is immersed in a coagulation bath and phase separation is performed. The temperature during phase separation is -5℃ to 30℃.

[0044] This step involves solvent-induced phase separation. Because the coagulation bath and organic solvent have different solubilities for the solute (the coagulation bath has a poorer solubilization capacity), when the slurry comes into contact with the coagulation bath, it disrupts the solvation equilibrium of the slurry, causing the organic solvent to separate out. This leads to the contraction of the polymer chains in the slurry and the formation of a compact conformation, ultimately initiating a microscopic phase separation structure and forming a porous functional layer. In this step, the temperature during phase separation needs to be within the range of -5℃ to 30℃, preferably 0 to 25℃, combined with a slurry with a viscosity of 1,000,000 mPa·s to 2,000,000 mPa·s. This slows down the immersion rate of the coagulation bath, suppressing instantaneous phase separation. Delayed phase separation occurs in the slurry, and the final functional layer is a dense structure mainly composed of honeycomb pores. In this step, the functional layer is formed in one step through a phase transformation process, and part of the functional layer is embedded in the support layer. The functional layer and the support layer form a chemical and structural whole, with no clear interface between the two layers, which can effectively reduce the occurrence of interlayer delamination.

[0045] Of course, the resulting product will undergo further post-processing such as washing and drying, which will not be elaborated here.

[0046] In this embodiment, by setting the viscosity of the slurry and the D50 particle size of the inorganic hydrophilic filler within a suitable range, and subsequently matching it with a suitable temperature during phase separation, instantaneous phase separation of the slurry can be suppressed, thereby forming a functional layer with a predominantly honeycomb porous structure. Compared with the prior art, the preparation method provided in this embodiment is simple, and the resulting separator membrane has both good gas barrier properties and good ionic conductivity, as well as good stability.

[0047] The separating membrane in this embodiment can be used in an alkaline electrolysis device. Specifically, the alkaline electrolysis device includes an electrolysis chamber, in which an anode and a cathode are disposed. The separating membrane is located between the anode and the cathode to isolate them. When the alkaline electrolysis device in this embodiment operates in a KOH solution with a concentration of 25%-30% at 70℃~90℃, the energy consumption of the alkaline electrolysis device is low due to the low sheet resistance of the alkaline separating membrane. Furthermore, due to the high bubble point of the alkaline separating membrane, the safe operating range of the alkaline electrolysis device is wider, and the purity of the output hydrogen is higher.

[0048] The technical solution of this application will be described in detail below with reference to embodiments: Test methods and equipment Slurry viscosity test The viscosity of the release liner slurry was tested using a Brookfield DV Plus viscometer at an ambient temperature of (23±5)℃ and a relative humidity of (50±20%). During the test, the slurry was placed in a suitable container, and the appropriate rotor and speed were selected according to the instrument's instruction manual. The viscosity value (unit: mPa·s) under steady-state conditions was recorded. This method reflects the rheological properties of the slurry under coating process conditions, providing a basis for optimizing process parameters.

[0049] Functional layer porosity test The liquid permeation method was used, with water (surface tension of about 72.3 dynes / cm) as the wetting fluid instead of the traditional mercury intrusion method. The mass difference of the sample in the dry state and the saturated water state was measured, and the porosity of the isolation membrane was calculated in combination with the density.

[0050] Surface resistance test A battery tester was used at a frequency ≥1000Hz and a temperature of approximately 30℃. The test system consisted of a platinum sheet – a KOH-immersed separator – a platinum sheet. The impedance difference between single-sheet and double-sheet separator systems was compared to calculate the surface resistance of the second separator. The specific operation for measuring the separator impedance is as follows: 1. The sample was cut to a size of 2.3 × 3.3 cm; 2. Soak in 30% KOH for ≥6 hours; 3. Add 30% KOH to the test fixture and maintain the temperature at 30℃; 4. After placing the isolation membrane, record the impedance value.

[0051] Bubble point and functional layer pore size testing The bubble point of the separator was tested using a PMI Capillary Flow Porometer (CFP-1500AE) with water as the wetting solution and a surface tension of 72.3 dynes / cm. The bubble point was obtained using a wet-dry method, where the material was wetted first and then dried. The bubble pressure was the bubble point. This instrumental method can also measure the pore size distribution, thus obtaining the average pore size data.

[0052] Morphology test The morphology of the separator was tested using a transmission electron microscope (TEM).

[0053] Example 1 This embodiment provides a separating membrane, the preparation method of which is as follows: The solute is dispersed in an organic solvent and, after stirring and defoaming, a slurry with a viscosity of 1,800,000 mPa·s is formed. The organic solvent is NMP, and the solute includes 75% inorganic hydrophilic filler and 25% polymer matrix. The inorganic hydrophilic filler is ZrO2 with a D50 particle size of 0.3 μm.

[0054] The slurry is applied to the upper and lower surfaces of the support layer using a scraper, allowing the slurry to penetrate into the support layer, which is made of PPS.

[0055] The support layer containing the slurry was immersed in a coagulation bath and phase separation was carried out at 15°C.

[0056] Examples 2 to 5 Except for changing the D50 particle size of the inorganic hydrophilic filler according to Table 1, the rest is basically the same as in Example 1.

[0057] Examples 6-7 Except for changing the type of inorganic hydrophilic filler according to Table 1, the rest is basically the same as in Example 1.

[0058] Examples 8-9 Except for changing the content of inorganic hydrophilic filler and polymer matrix according to Table 1, the rest is basically the same as in Example 1.

[0059] Examples 10-11 Except for changing the temperature during phase separation according to Table 1, the rest is basically the same as in Example 1.

[0060] Comparative Examples 1-2 Except for changing the viscosity of the slurry according to Table 1, the rest is basically the same as in Example 1.

[0061] Comparative Examples 3-4 Except for changing the D50 particle size of the inorganic hydrophilic filler according to Table 1, the rest is basically the same as in Example 1.

[0062] Comparative Examples 5 to 6 Except for changing the temperature during phase separation according to Table 1, the rest is basically the same as in Example 1.

[0063] Table 1

[0064] As can be seen from the table, the isolation membrane in this embodiment has a high bubble point and a low resistance, which indicates that the isolation membrane in this embodiment has both good gas isolation performance and good ionic conductivity.

[0065] Specifically, as shown in Example 1 and Comparative Examples 1-2, if the viscosity of the slurry is too high or too low, the pore size or average pore diameter of the formed functional layer cannot meet the requirements of the functional layer in the embodiments of this application. If the viscosity is too low, a honeycomb pore structure cannot be formed, resulting in a decrease in the bubble point pressure of the separator and a decrease in gas barrier performance. If the viscosity is too high, the porosity will be relatively reduced, and the sheet resistivity will decrease. As shown in Example 1 and Comparative Examples 3-4, if the D50 particle size of the inorganic hydrophilic filler is not in the range of 0.3μm to 1.5μm, it will significantly affect the slurry viscosity, thereby affecting the pore size. If the viscosity is too high, it will be difficult to form honeycomb pores, and the sheet resistivity of the separator will also be affected due to the difference in the specific surface area of ​​the filler. As can be seen from Examples 1 and Comparative Examples 5-6, if the temperature during phase separation is too high, instantaneous phase separation is likely to occur, and "finger-like pores" will form in the functional layer. At this time, the pore size of the functional layer is too large, which has a positive effect on the surface resistance, but does not necessarily increase the porosity. In addition, it will also lead to a relative decrease in the bubble point of the separator and a deterioration in the gas barrier performance. If the temperature during phase separation is too low, the pore size in the functional layer is too small, resulting in an excessively high surface resistance of the separator and poor ionic conductivity.

[0066] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A separating membrane, characterized in that, It includes a support layer, and a functional layer is provided on the surface of the support layer, with the functional layer partially embedded in the support layer; The porosity of the functional layer is 53%~65%, the average pore diameter of the pores in the functional layer is 50nm~110nm, and the average pore diameter of the pores in the support layer is greater than the average pore diameter of the pores in the functional layer. The functional layer includes an inorganic hydrophilic filler and a polymer matrix, wherein the D50 particle size of the inorganic hydrophilic filler is 0.3μm~1.5μm.

2. The separator membrane according to claim 1, characterized in that, The inorganic hydrophilic filler includes at least one of ZrO2, TiO2, or CeO2.

3. The separator membrane according to claim 1, characterized in that, The polymer matrix includes at least one of polystyrene, polyphenylene sulfone, polyether sulfone, or bisphenol A type polysulfone.

4. The separator according to claim 1, characterized in that, In the functional layer, the mass ratio of the inorganic hydrophilic filler to the polymer matrix is ​​70:30 to 90:

10.

5. The separator membrane according to claim 1, characterized in that, The thickness of the isolation membrane is 200μm~550μm.

6. The separator according to claim 1, characterized in that, The bubble point of the separator is 8 bar to 22 bar, and the sheet resistivity of the separator is 0.16 Ω / cm. 2 ~0.23Ω / cm 2 .

7. A method for preparing the separator membrane according to any one of claims 1 to 6, characterized in that, Includes the following steps: An inorganic hydrophilic filler, a polymer matrix, and an organic solvent are mixed to form a slurry. The inorganic hydrophilic filler has a D50 particle size of 0.3 μm to 1.5 μm, and the slurry has a viscosity of 1,000,000 mPa·s to 2,000,000 mPa·s. The slurry is applied to the surface of the support layer, and the slurry is allowed to penetrate into the support layer. The slurry is subjected to phase separation in a coagulation bath to form a layer, and the temperature during phase separation is -5℃ to 30℃.

8. The method for preparing the separator according to claim 7, characterized in that, The organic solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N-ethylpyrrolidone, dimethyl sulfoxide, or tetramethyl sulfoxide.

9. The method for preparing the separator according to claim 7, characterized in that, The coagulation bath includes at least one of water, methanol, ethanol, or isopropanol.

10. An alkaline electrolysis device, characterized in that, The device includes an electrolysis chamber, wherein an anode and a cathode are disposed within the electrolysis chamber, and an isolation membrane is disposed between the anode and the cathode, the isolation membrane being used to isolate the anode and the cathode; the isolation membrane is the isolation membrane according to any one of claims 1 to 6, or the isolation membrane is prepared by the method of preparing the isolation membrane according to any one of claims 7 to 9.

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