Alumina oxyhydroxide-based alkaline electrolytic water composite separator and method for preparing the same
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INNER MONGOLIA UNIVERSITY
- Filing Date
- 2026-04-03
- Publication Date
- 2026-08-07
AI Technical Summary
[0003]目前，商业化的碱性电解槽主要采用聚苯硫醚(PPS)织物隔膜或有机-无机复合隔膜；然而，PPS织物隔膜存在本征疏水性强、气密性差等问题，导致面电阻较高，电解能耗大；近年来，采用聚砜(PSF)为基体、ZrO2为填料的复合隔膜因其优异的耐碱稳定性受到广泛关注，但ZrO2原料成本较高(约4万元/吨)，限制了其在规模化制氢中的应用推广
本发明提供的羟基氧化铝基碱性电解水复合隔膜，通过在聚砜树脂基体中添加不超过其质量80%的羟基氧化铝作为填料，利用羟基氧化铝表面富含羟基的本征亲水性，在无需额外亲水改性的条件下显著提升隔膜的润湿性能，同时羟基氧化铝在聚砜基体中构建的亲水网络为OH-提供了连续传输通道，有效降低了隔膜的面电阻；此外，羟基氧化铝原料成本仅为ZrO2的10%～20%，大幅降低了隔膜的原料成本，且通过控制羟基氧化铝添加量不超过聚砜质量的80%，避免了因填料过量导致的隔膜机械强度不足、无法成膜的问题，从而在保证隔膜综合性能的前提下，实现了低成本、高亲水性、低面电阻的碱性电解水复合隔膜的制备，有效解决了现有技术中ZrO2基复合隔膜成本高、传统亲水改性长效性不足的技术问题。
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Figure CN122522320A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of alkaline water electrolysis for hydrogen production membrane technology, specifically to a hydroxyalumina-based alkaline water electrolysis composite membrane and its preparation method. Background Technology
[0002] As a core component of the electrolyzer, the performance of the diaphragm directly determines the electrolysis efficiency, hydrogen purity, and system safety. An ideal diaphragm material must simultaneously possess low surface resistivity, high gas barrier properties, excellent mechanical strength, and long-term alkali resistance.
[0003] Currently, commercial alkaline electrolyzers mainly use polyphenylene sulfide (PPS) fabric membranes or organic-inorganic composite membranes. However, PPS fabric membranes have problems such as strong intrinsic hydrophobicity and poor airtightness, resulting in high sheet resistance and high electrolysis energy consumption. In recent years, composite membranes using polysulfone (PSF) as the matrix and ZrO2 as the filler have attracted widespread attention due to their excellent alkali resistance. However, the high cost of ZrO2 raw material (approximately RMB 40,000 / ton) limits its application and promotion in large-scale hydrogen production.
[0004] Therefore, how to develop a novel composite membrane that combines excellent hydrophilicity, low surface resistivity, good mechanical strength, and low raw material cost has become a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hydroxyalumina-based alkaline water electrolysis composite membrane and its preparation method.
[0006] To achieve the above objectives, the present invention provides the following technical solution: This application provides an alumina-based alkaline water electrolysis composite membrane, the composite membrane comprising a polysulfone resin matrix and alumina filler dispersed in the polysulfone resin matrix, wherein the mass of the alumina does not exceed 80% of the mass of the polysulfone resin.
[0007] Further, the mass of the aluminum hydroxide is 10% to 80% of the mass of the polysulfone resin; preferably, it is 30% to 50%.
[0008] Furthermore, the microstructure of the aluminum hydroxyaluminate is fibrous or lamellar.
[0009] Furthermore, the composite diaphragm has a sheet resistance of no more than 0.1 Ω·cm², a water contact angle of no more than 70°, and a tensile strength of no less than 0.3 MPa under conditions of 30 wt% KOH and 60°C.
[0010] The present invention also provides a method for preparing the above-mentioned hydroxyalumina-based alkaline water electrolysis composite membrane, comprising the following steps: Polysulfone resin and a porogen are mixed in an organic solvent to form a polymer solution; Alumina hydroxyl powder was added to the polymer solution, dispersed evenly, and then degassed to obtain a casting solution. The casting solution is scraped into a film, which is then transformed into a wet diaphragm through phase inversion. The wet diaphragm is washed and dried to obtain the composite diaphragm.
[0011] Furthermore, the pore-forming agent is polyvinylpyrrolidone, and its mass ratio with polysulfone resin is 0.8 to 1.2:1.
[0012] Furthermore, the organic solvent is N-methylpyrrolidone, and the mass ratio of polysulfone resin to N-methylpyrrolidone is 1:1.5 to 4.0.
[0013] Furthermore, in the phase transformation step, the coagulation bath is selected from one or more of deionized water, a mixed solution of N-methylpyrrolidone and deionized water, ethanol, or methanol, and the coagulation bath temperature is 0–60°C.
[0014] Furthermore, in the casting solution, the mass ratio of polysulfone resin, pore-forming agent and alumina hydroxyl is 1:0.8-1.2:0.1-0.6.
[0015] Compared with the prior art, this application has the following beneficial effects: The hydroxyl alumina-based alkaline water electrolysis composite membrane provided by this invention significantly improves the wettability of the membrane by adding no more than 80% by mass of hydroxyl alumina as a filler to a polysulfone resin matrix. This is achieved by utilizing the intrinsic hydrophilicity of the hydroxyl groups on the surface of hydroxyl alumina, without requiring additional hydrophilic modification. Furthermore, the hydrophilic network constructed by hydroxyl alumina in the polysulfone matrix is an OH- - It provides a continuous transmission channel, effectively reducing the sheet resistance of the diaphragm. In addition, the raw material cost of alumina hydroxyl is only 10% to 20% of that of ZrO2, which greatly reduces the raw material cost of the diaphragm. Furthermore, by controlling the amount of alumina hydroxyl to not exceed 80% of the mass of polysulfone, the problem of insufficient mechanical strength and inability to form a film due to excessive filler is avoided. Thus, under the premise of ensuring the comprehensive performance of the diaphragm, the preparation of a low-cost, highly hydrophilic, and low sheet resistance alkaline water electrolysis composite diaphragm is realized, effectively solving the technical problems of high cost of ZrO2-based composite diaphragms and insufficient long-term performance of traditional hydrophilic modification in the prior art. Attached Figure Description
[0016] Figure 1 This is a SEM image of the cross-section of the composite diaphragm prepared in Example 1 of the present invention.
[0017] Figure 2 This is a SEM image of the surface of the composite membrane prepared in Example 1 of the present invention.
[0018] Figure 3 This is a comparison diagram of the contact angle between Comparative Example 1 of the present invention and water.
[0019] Figure 4 This is a comparison diagram of the contact angle between the present invention embodiment 1 and water.
[0020] Figure 5 The graph shows a comparison of tensile strength and elongation at break for embodiments 1, 2, 3, 4, 5, 6, 7, and 8 of the present invention.
[0021] Figure 6 This is a comparison chart of alkali absorption in Examples 1, 2, 3, 4, 5, 6, 7, and 8 of the present invention.
[0022] Figure 7 The above are comparison charts of bubble point pressures for embodiments 1, 2, 3, 4, 5, 6, 7, and 8 of the present invention.
[0023] Figure 8 The diagram shows a comparison of the surface resistance of embodiments 1, 2, 3, 4, 5, 6, 7, and 8 of the present invention.
[0024] Figure 9 The polarization curve of Example 3 of the present invention is obtained under the conditions of 30wt% KOH, 60℃, and a current density of 500mA / cm² at a voltage of 1.7V. Detailed Implementation
[0025] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] The polysulfone resin used in the embodiments of the present invention was purchased from Dalian Polysulfone Plastics Co., Ltd., with a molecular weight of 80,000; polyvinylpyrrolidone was purchased from Sinopharm Group, with a molecular weight of 40,000; N-methylpyrrolidone was of analytical grade; and alumina hydroxyaluminate was prepared by hydrothermal method or purchased commercially, and its microstructure was fibrous or sheet-like.
[0027] The preparation method of the composite diaphragm is described in detail below, in conjunction with the technical solution of this application: Example 1: Preparation of 10% aluminum hydroxide composite membrane S1: Slowly add 2g of polysulfone resin powder to 15mL of N-methylpyrrolidone and stir at 300rpm for 4h at room temperature to obtain a polysulfone resin solution. S2: Add 2g of polyvinylpyrrolidone to the above solution and continue stirring for 1 hour until completely dissolved to form a homogeneous mixed solution; S3: Add 0.2g of alumina hydroxyl powder (10% of the mass of polysulfone) to the mixed solution, adjust the stirring speed to 200rpm, and continue stirring for 24h to make it evenly dispersed. Then, slowly stir to degas for 2h to obtain the casting solution. S4: Pour the casting solution onto a clean glass plate and use a 500μm scraper to uniformly coat the liquid film. After pre-evaporation for 15 seconds, immediately immerse it in a 15℃ deionized water coagulation bath and keep it submerged for 24 hours to allow the solvent and non-solvent to fully exchange and form a wet composite membrane. S5: Take out the wet composite membrane, rinse it repeatedly with deionized water to remove residual solvent, and dry it at 60°C for 24 hours to obtain the composite membrane, which is denoted as A10.
[0028] Example 2: Preparation of 20% Alumina Hydroxide Composite Membrane The preparation method is basically the same as in Example 1, except that 0.4g of aluminum hydroxide powder (accounting for 20% of the mass of polysulfone) is added in step S3, which is denoted as A20.
[0029] Example 3: Preparation of 30% aluminum hydroxide composite membrane The preparation method is basically the same as in Example 1, except that 0.6g of aluminum hydroxide powder (accounting for 30% of the mass of polysulfone) is added in step S3, which is denoted as A30.
[0030] Example 4: Preparation of 40% aluminum hydroxide composite membrane The preparation method is basically the same as in Example 1, except that 0.8g of aluminum hydroxide powder (accounting for 40% of the mass of polysulfone) is added in step S3, which is denoted as A40.
[0031] Example 5: Preparation of 50% Alumina Hydroxide Composite Membrane The preparation method is basically the same as in Example 1, except that 1.0 g of aluminum hydroxide powder (accounting for 50% of the mass of polysulfone) is added in step S3, which is denoted as A50.
[0032] Example 6: Preparation of 60% aluminum hydroxide composite membrane The preparation method is basically the same as in Example 1, except that 1.2g of aluminum hydroxide powder (accounting for 60% of the mass of polysulfone) is added in step S3, which is denoted as A60.
[0033] Example 7: Preparation of 70% aluminum hydroxide composite membrane The preparation method is basically the same as in Example 1, except that 1.4g of aluminum hydroxide powder (accounting for 70% of the mass of polysulfone) is added in step S3, which is denoted as A70.
[0034] Example 8: Preparation of 80% aluminum hydroxide composite membrane The preparation method is basically the same as in Example 1, except that 1.6g of aluminum hydroxide powder (accounting for 80% of the mass of polysulfone) is added in step S3, which is denoted as A80.
[0035] Comparative Example 1: Preparation of pure polysulfone membrane The preparation method is basically the same as in Example 1, except that aluminum hydroxide powder, denoted as PSF, is not added in step S3.
[0036] The performance of the composite membranes prepared using the processes of Examples 1-8 and Comparative Example 1 is tested below, with reference to the accompanying drawings: The microstructure of the composite diaphragm prepared in Example 1 was observed using scanning electron microscopy. The results are as follows: Figure 1 (section) and Figure 2 As shown on the surface, spherical particles are uniformly dispersed in the polysulfone matrix, and fibrous alumina hydroxyl particles overlap to form a three-dimensional network structure without obvious agglomeration or defects.
[0037] Example 1 was tested using a contact angle meter, and the results are as follows: Figure 4 As shown in the figure. Test comparison example 1, the results are as follows. Figure 3 As shown, the contact angle of Example 1 was 69.592°, and the contact angle of Comparative Example 1 was 86.568°, indicating that the introduction of aluminum hydroxyaluminate significantly improved the hydrophilicity of the membrane.
[0038] The tensile strength of the composite diaphragms prepared in Examples 1-8 and the comparative examples was tested using a universal testing machine. The results are shown in Table 1. As the alumina content increased from 20% to 80%, the tensile strength of the diaphragms showed a continuous decreasing trend: A10-R was 2.3 MPa, A20-R was 1.8 MPa, A30-R was 1.7 MPa, A40-R was 1.6 MPa, A50-R was 1.3 MPa, A60-R was 1.0 MPa, A70-R was 0.4 MPa, and A80-R was 0.3 MPa. When the content reached 60%, the strength dropped to 1.0 MPa, a decrease of 56.5% compared to the 20% sample; when the content further increased to 70%, the strength was only 0.4 MPa, a decrease of 82.6%. The comparison of content with tensile strength and elongation at break is shown in the figure below. Figure 5 As shown.
[0039] The alkali absorption of Examples 1-8 was tested using the gravimetric method, and the results are as follows: Figure 6 As shown, as the content of aluminum hydroxide increases from 10% to 80%, the alkali absorption first increases and then tends to stabilize, indicating that the hydrophilic properties of aluminum hydroxide improve the membrane's ability to absorb and retain electrolyte.
[0040] Bubble point pressure was measured by adjusting the amount of nitrogen gas using a fixture and regulating valve. Bubble point pressures were tested for Examples 1-8. The pressures from A10 to A30 showed a decreasing trend, while A40 showed a significant increase. Subsequently, the pressures from A40 to A80 continued to decrease. Figure 7 As shown.
[0041] The sheet resistivity of Examples 1-8 and Comparative Example 1 was tested using the Chenhua electrochemical workstation in 30wt% KOH solution at different temperatures. The results are shown in [Figure number missing]. Figure 8 Examples 1-8 at 60°C were summarized, and the results are shown in Table 1. As the content of aluminum hydroxide increased, the sheet resistivity showed a trend of first decreasing and then increasing. Among them, A70 (70% addition) had the lowest sheet resistivity at 0.010 Ω·cm², which was much lower than that of the pure PSF film at 0.186 Ω·cm².
[0042] Polarization curves were tested on Example 3 (A30). Under conditions of 30wt% KOH and 60°C, the current density at 1.7V reached 500mA / cm², which is 21.9% higher than that of the pure PSF film (500mA / cm²). Figure 9 As shown, the hydroxyalumina composite membrane exhibits good electrolytic performance.
[0043] The sheet resistance of the composite membranes prepared in Examples 1-8 and the comparative example was tested at 60°C using a sheet resistance measuring fixture. The results are shown in Table 1. A70 had the lowest sheet resistance, which ensured its good conductivity. Overall, the composite membrane A70 has better performance and is more suitable for practical use.
[0044] Table 1. Performance comparison of composite membranes with different aluminum hydroxide contents: Table 1 shows that when the amount of alumina hydroxyacid added is within the range of 10%-80%, the resulting composite membranes all exhibit good film-forming properties. With increasing addition, the hydrophilicity of the membrane significantly improves (contact angle decreases from 86.5° to a minimum of 38.4°), and the sheet resistivity generally decreases (reaching a minimum of 0.010 Ω·cm²). Tensile strength decreases with increasing addition, but when the addition amount does not exceed 80%, the tensile strength is not lower than 0.3 MPa, which meets the practical application requirements of alkaline water electrolysis for hydrogen production membranes.
[0045] It should be noted that when the amount of aluminum hydroxyacid added exceeds 80% of the mass of polysulfone, the membrane cannot form a film due to insufficient mechanical strength; therefore, the effective addition range of aluminum hydroxyacid is 10%-80%, preferably 30%-50%.
[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0047] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A hydroxyalumina-based alkaline water electrolysis composite membrane, characterized in that, The composite membrane comprises a polysulfone resin matrix and an alumina hydroxyl filler dispersed in the polysulfone resin matrix, wherein the mass of the alumina hydroxyl filler does not exceed 80% of the mass of the polysulfone resin.
2. The hydroxyalumina-based alkaline water electrolysis composite membrane according to claim 1, characterized in that, The mass of the aluminum hydroxide is 10% to 80% of the mass of the polysulfone resin.
3. The hydroxyalumina-based alkaline water electrolysis composite membrane according to claim 2, characterized in that, The mass of the alumina hydroxyl is 30% to 50% of the mass of the polysulfone resin.
4. The hydroxyalumina-based alkaline water electrolysis composite membrane according to claim 1, characterized in that, The microstructure of the aluminum hydroxide is fibrous or lamellar.
5. The hydroxyalumina-based alkaline water electrolysis composite membrane according to claim 1, characterized in that, The composite diaphragm has a sheet resistance of no more than 0.1 Ω·cm², a water contact angle of no more than 70°, and a tensile strength of no less than 0.3 MPa under the conditions of 30 wt% KOH and 60°C.
6. A method for preparing a hydroxyalumina-based alkaline water electrolysis composite membrane as described in any one of claims 1-5, characterized in that, Includes the following steps: Polysulfone resin and a porogen are mixed in an organic solvent to form a polymer solution; Alumina hydroxyl powder was added to the polymer solution, dispersed evenly, and then degassed to obtain a casting solution. The casting solution is scraped into a film, which is then transformed into a wet diaphragm through phase inversion. The wet diaphragm is washed and dried to obtain the composite diaphragm.
7. The preparation method according to claim 6, characterized in that, The pore-forming agent is polyvinylpyrrolidone, and the mass ratio of polyvinylpyrrolidone to polysulfone resin is 0.8 to 1.2:
1.
8. The preparation method according to claim 6, characterized in that, The organic solvent is N-methylpyrrolidone, and the mass ratio of the polysulfone resin to N-methylpyrrolidone is 1:1.5 to 4.
0.
9. The preparation method according to claim 6, characterized in that, In the phase transformation step, the coagulation bath is selected from one or more of deionized water, a mixed solution of N-methylpyrrolidone and deionized water, ethanol or methanol, and the coagulation bath temperature is 0 to 60°C.
10. The preparation method according to claim 6, characterized in that, In the casting solution, the mass ratio of polysulfone resin, pore-forming agent and alumina hydroxyl is 1:0.8-1.2:0.1-0.6.