A bifunctional ion-conducting anion exchange composite membrane, and a preparation method and application thereof

Abstract

The present application relates to a kind of bifunctional ion conduction anion exchange composite membrane and its preparation method and application, the composite membrane with alkali-resistant polymer, pore-forming agent and zirconium dioxide as slurry base component, then introduce guar gum hydroxypropyl trimethyl ammonium chloride GC and be coated on support preparation is obtained.The present application reduces the migration energy barrier of OH ‑ By part quaternary ammonium structure in guar gum hydroxypropyl trimethyl chloride, while ensuring high structural stability, the obtained anion exchange composite membrane realizes bifunctional conduction by channel transmission and ion hopping, and has good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of alkaline water electrolysis hydrogen production technology, and specifically relates to a bifunctional ion-conducting anion-exchange composite membrane, its preparation method, and its application. Background Technology

[0002] Hydrogen, a renewable energy source, has garnered significant attention due to its zero-pollution, high energy density, and easy availability. With technological advancements and improved living standards, the applications of hydrogen are expanding, primarily including fuel cell vehicles, hydrogen medicine, and industrial production. In particular, low-temperature water electrolysis technology has become an ideal method for green hydrogen production due to its high technological maturity, competitive operating costs, and superior performance characteristics. Water electrolysis technologies can be broadly categorized based on the core membrane material within the electrolyzer: alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), and anion exchange membrane water electrolysis (AEMWE). Among these, AWE technology boasts high maturity and has achieved large-scale commercial application.

[0003] The development of AWE technology has witnessed three major revolutions in alkaline membranes. First-generation asbestos mesh has been phased out due to environmental and safety concerns during production. Second-generation polyphenylene sulfide (PPS) fabrics offer excellent stability and flexibility while simplifying the manufacturing process; however, practical applications revealed drawbacks including excessive thickness, low hydrophilicity, poor gas purity, and low electrolysis efficiency. Currently available third-generation membranes are typically porous composite membranes produced using phase inversion technology, characterized by combining alkali-resistant polymers such as polysulfone, polyphenylene sulfide, and polyetheretherketone (PEEK) with hydrophilic inorganic fillers. These porous composite membranes typically promote OH-... - Gas transfer primarily occurs through internal channels, therefore pore size and film thickness directly affect performance. Excessively large pores or films can cause gas crossflow within the channels, posing safety risks. Conversely, excessively small pores or overly thick films can impede OH-. - The passage of [a substance] results in poor conductivity. Therefore, the development of highly efficient OH [materials] is needed. - Composite membranes with excellent transport and gas barrier properties are crucial for the development of water electrolysis. In recent years, research on improving the bubble point pressure and hydrophilicity of alkaline composite membranes has relied on filling or coating with additional materials to reduce pore size, rather than adjusting the inherent chemical structure of the materials themselves [eScience, 4(2024), 100290, ACS Appl. Mater. Interfaces, 16(2023), 1394-1403]. Pore size adjustment in porous membranes is a key factor affecting the performance of water electrolysis.

[0004] During pore size adjustment, microporous membranes exhibit high gas barrier properties, enabling the development of thinner anion exchange membrane structures for composite membranes. In AEMWE systems, the separation membrane thickness is typically 1–100 micrometers, as seen in commercial AEMs such as Fumasep®, Sustainion®, Aemion®, and PiperION®. - Anion exchange membranes utilize cation transport via high-density cation sites within the membrane, rather than direct pore transport. Key cation sites include quaternary ammonium, quaternary phosphorus, piperidinium / pyrrolidineonium, and other framework cations. However, AEMs still face several challenges hindering their large-scale production and application, primarily including: 1) degradation of the polymer backbone and cationic groups under strongly alkaline conditions; 2) complex synthesis procedures and high costs; and 3) toxicity issues related to some fluorinated polymer backbones [Accounts of Chemical Research, 58(2025), 688-702]. In contrast, organic-inorganic composite membranes offer advantages such as simple manufacturing, high alkali resistance, and environmental friendliness. Combining the efficient pore transport of porous composite membranes with the inherent ion site transport of AEMs shows great potential in the development of next-generation anion exchange composite membranes. Summary of the Invention

[0005] This invention provides a bifunctional ion-conducting anion-exchange composite membrane, its preparation method, and its application, solving the technical problems of existing AWE system composite membranes with high thickness (100-500 mm) and large ohmic polarization, and AEMWE system membranes with easy degradation, poor stability, and high preparation cost under strong alkaline conditions.

[0006] This invention provides a bifunctional ion-conducting anion-exchange composite membrane. The composite membrane is prepared by using an alkali-resistant polymer, a pore-forming agent, and zirconium dioxide as the basic components of a slurry, then introducing guar gum hydroxypropyltrimethylammonium chloride (GC) and coating it onto a support. This membrane is denoted as ZPGG. X , 0.1≤x≤2.

[0007] Preferably, the alkali-resistant polymer is polysulfone (PSU).

[0008] Preferably, the pore-forming agent is polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP).

[0009] Preferably, the support material is polyphenylene sulfide (PPS).

[0010] Preferably, the zirconium dioxide particle size is 100~200 nm.

[0011] This invention also provides a method for preparing a bifunctional ion-conducting anion-exchange composite membrane, comprising the following steps:

[0012] (1) Dissolve the alkali-resistant polymer in an organic solvent by stirring, then add a pore-forming agent and mix; add zirconium dioxide into the solution, stir evenly and remove bubbles by ultrasonication to obtain a slurry;

[0013] (2) Disperse guar gum hydroxypropyltrimethylammonium chloride GC in an organic solvent and stir thoroughly. Then add the resulting dispersion system to the above slurry until it is stirred evenly.

[0014] (3) The slurry obtained in step (2) is poured onto the support and coated, and then immersed in ethanol for phase inversion to obtain a bifunctional ion-conducting anion-exchange composite membrane.

[0015] Preferably, the organic solvent in step (1) is N-methylpyrrolidone (NMP); the mass ratio of the alkali-resistant polymer to the organic solvent is 1:2-10.

[0016] Preferably, the porogen in step (1) is polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) in a mass ratio of 1:1; the mass ratio of the porogen to the alkali-resistant polymer is 1:2-4.

[0017] Preferably, the mass ratio of the alkali-resistant polymer to zirconium dioxide in step (1) is 1:2-4.

[0018] Preferably, the organic solvent in step (2) is N-methylpyrrolidone (NMP); the mass ratio of GC to organic solvent is 1:2-10; and the mass ratio of GC to alkali-resistant polymer is 1-3:2-4.

[0019] This invention also provides an application of a bifunctional ion-conducting anion-exchange composite membrane in alkaline water electrolysis for hydrogen production.

[0020] Beneficial effects

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] (1) By using a dual pore-forming agent (polyvinylpyrrolidone / polyethylene glycol) to induce the synergistic effect of dipole moment and component modulation, and at the same time introducing cation (GC) sites, an anion exchange membrane composite membrane with surface micro / nanopore structure is realized.

[0023] (2) By introducing cation sites into the composite system, a dual-function OH group that combines pore transport and site hopping is achieved. - Conduction.

[0024] (3) Partial quaternization in GC reduces OH - The migration energy barrier is reduced, while ensuring high structural stability. Furthermore, the quaternized components with charge in GC exhibit an enhanced interfacial binding effect with ZrO2.

[0025] (4) The ZPGG1 membrane in this invention exhibits high bubble point pressure (3.9 bar) and low areal resistivity (0.14 Ω·cm). -2 ).

[0026] (5) The ZPGG1 membrane in this invention exhibits excellent water electrolysis performance (18900 A / m). 2 @2V), while at 10000A / m 2 After 480 hours of stable operation under high current density conditions, the composite membrane still maintains a stable structure, meeting the requirements of practical commercial applications. Attached Figure Description

[0027] Figure 1 ZPGG0 and ZPGG were prepared for the examples and comparative examples. 0.5 ZPGG1, ZPGG 1.5 SEM image of the anion exchange composite membrane.

[0028] Figure 2 ZPGG0 and ZPGG were prepared for the examples and comparative examples. 0.5 ZPGG1, ZPGG 1.5 KOH absorption rate and water contact angle of anion exchange composite membrane.

[0029] Figure 3 ZPGG0 and ZPGG were prepared for the examples and comparative examples. 0.5 ZPGG1, ZPGG 1.5 Bubble point pressure (a) and sheet resistance (b) of anion exchange composite membrane.

[0030] Figure 4 ZPGG0 and ZPGG were prepared for the examples and comparative examples. 0.5 ZPGG1, ZPGG 1.5 The ion exchange capacity (a), conductivity (b), and activation energy (c) of the anion exchange composite membrane, as well as its schematic diagram (d).

[0031] Figure 5 ZPGG0 and ZPGG were prepared for the examples and comparative examples. 0.5 ZPGG1, ZPGG 1.5 Anion exchange composite membrane in 30% KOH, 80 o Polarization curves at operating temperature C and cell pressure 2V.

[0032] Figure 6 The long-term operational stability of the ZPGG1 anion exchange composite membrane prepared in Example 3 is shown. Detailed Implementation

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] The polysulfone (PSU, S6010) used in the following examples was purchased from BASF. Polyethylene glycol (PEG, analytical grade, molecular weight ~2000), N-methylpyrrolidone (NMP, analytical grade, 98%), polyvinylpyrrolidone (PVP, analytical grade, molecular weight ~30000), zirconium dioxide (ZrO2, 100 nm), guar hydroxypropyltrimethylammonium chloride (GC, analytical grade, viscosity ≥2000 mpas, N: 1.3~1.7%), and potassium hydroxide (KOH, analytical grade, ≥85.0%) were purchased from Sinopharm Chemical Reagent Co., Ltd. Polyphenylene sulfide (PPS) mesh fabric was purchased from Mitech Ltd.

[0035] Comparative Example 1

[0036] This comparative example provides a method for preparing anion exchange composite membrane, the specific steps of which are as follows:

[0037] Step 1: PSU was completely dissolved in NMP after continuous mechanical stirring for 24 h, with a PSU to NMP mass ratio of 1:5. Subsequently, the composite porogens PEG and PVP were added to the above solution and continuously stirred to ensure thorough mixing. The mass ratio of PEG to PVP was 1:1, and the mass ratio of PEG, PVP, and PSU was 1:1:4.

[0038] Step 2: Add ZrO2 to the above solution, stir evenly and use ultrasound to remove air bubbles from the slurry to obtain a uniform milky white slurry.

[0039] Step 3: Place the PPS mesh fabric on a glass plate, maintaining a gap of 500 μm between the doctor blade and the glass plate. Pour the mixed slurry onto the PPS mesh fabric and coat it with a doctor blade, then immerse it in ethanol for phase inversion to obtain the ZPGG0 anion exchange composite membrane.

[0040] Example 1

[0041] Step 1: PSU was completely dissolved in NMP after continuous mechanical stirring for 24 h, with a PSU to NMP mass ratio of 1:5. Subsequently, the composite porogens PEG and PVP were added to the above solution and continuously stirred to ensure thorough mixing. The mass ratio of PEG to PVP was 1:1, and the mass ratio of PEG, PVP, and PSU was 1:1:4.

[0042] Step 2: Add ZrO2 to the above solution, stir evenly and use ultrasound to remove air bubbles from the slurry to obtain a uniform milky white slurry.

[0043] Step 3: Disperse GC in NMP and stir thoroughly, with a GC to NMP mass ratio of 1:2 and a GC to PSU mass ratio of 1:4. Then, slowly add the resulting dispersion to the above slurry and stir until homogeneous.

[0044] Step 4: Place the PPS mesh fabric on a glass plate, maintaining a 500 μm gap between the doctor blade and the glass plate. Pour the mixed slurry onto the PPS mesh fabric and coat it with a doctor blade. Immerse the coated fabric in ethanol for phase inversion to obtain ZPGG. 0.5 Anion exchange composite membrane.

[0045] Example 2

[0046] Step 1: PSU was completely dissolved in NMP after continuous mechanical stirring for 24 h, with a PSU to NMP mass ratio of 1:5. Subsequently, the composite porogens PEG and PVP were added to the above solution and continuously stirred to ensure thorough mixing. The mass ratio of PEG to PVP was 1:1, and the mass ratio of PEG, PVP, and PSU was 1:1:4.

[0047] Step 2: Add ZrO2 to the above solution, stir evenly and use ultrasound to remove air bubbles from the slurry to obtain a uniform milky white slurry.

[0048] Step 3: Disperse GC in NMP and stir thoroughly, with a GC to NMP mass ratio of 1:2 and a GC to PSU mass ratio of 1:2. Then, slowly add the resulting dispersion to the above slurry and stir until homogeneous.

[0049] Step 4: Place the PPS mesh fabric on a glass plate, maintaining a 500 μm gap between the doctor blade and the glass plate. Pour the mixed slurry onto the PPS mesh fabric and coat it with a doctor blade. Immerse it in ethanol for phase inversion to obtain the ZPGG1 anion exchange composite membrane.

[0050] Example 3

[0051] Step 1: PSU was completely dissolved in NMP after continuous mechanical stirring for 24 h, with a PSU to NMP mass ratio of 1:5. Subsequently, the composite porogens PEG and PVP were added to the above solution and continuously stirred to ensure thorough mixing. The mass ratio of PEG to PVP was 1:1, and the mass ratio of PEG, PVP, and PSU was 1:1:4.

[0052] Step 2: Add ZrO2 to the above solution, stir evenly and use ultrasound to remove air bubbles from the slurry to obtain a uniform milky white slurry.

[0053] Step 3: Disperse GC in NMP and stir thoroughly, with a GC to NMP mass ratio of 1:2 and a GC to PSU mass ratio of 3:4. Then, slowly add the resulting dispersion to the above slurry and stir until homogeneous.

[0054] Step 4: Place the PPS mesh fabric on a glass plate, maintaining a 500 μm gap between the doctor blade and the glass plate. Pour the mixed slurry onto the PPS mesh fabric and coat it with a doctor blade. Immerse the coated fabric in ethanol for phase inversion to obtain ZPGG. 1.5 Anion exchange composite membrane.

[0055] Performance testing:

[0056] (1) ZPGG0 and ZPGG were analyzed using an S-4800 scanning electron microscope (SEM) (Hitachi, Japan). 0.5 ZPGG1, ZPGG 1.5 The surface and cross-sectional microstructure of the anion exchange composite membrane were characterized.

[0057] like Figure 1 As shown, after dual regulation by PEG and PVP, the ZPGG0 composite membrane exhibits abundant micro / nanopores on its surface and cross-section. The introduction of GC further enriches the polymer network, resulting in ZPGG0... 0.5 ~ZPGG 1.5 The three composite films exhibited a more compact microstructure. OH - It can achieve rapid conduction through a dense quaternized polymer network while simultaneously transporting through micro- and nano-pores.

[0058] (2) ZPGG0, ZPGG 0.5 ZPGG1, ZPGG 1.5 The anion exchange composite membrane was cut into regular squares of 2 cm × 2 cm, washed three times with deionized water, and then dried under vacuum for 24 h. The mass of the dried membrane was recorded as A. d The sample was then immersed in a 30 wt% KOH solution at room temperature for 24 hours. After removal, the surface alkaline solution was wiped off with filter paper, and the sample was weighed and recorded as A. w The formula for calculating the KOH adsorption rate of the membrane is as follows:

[0059] .

[0060] The hydrophilicity of the composite membrane was evaluated using a water contact angle test, referring to GB / T 30693-2014 "Measurement of the contact angle between plastic films and water". The membrane was placed flat on a glass slide at room temperature, and a 2 μL droplet was injected into the membrane surface. A photograph was taken at the moment the droplet touched the membrane surface.

[0061] like Figure 2 As shown, the ZPGG0 composite membrane achieves an alkali absorption rate of 95% due to its abundant pores. Introducing the cationic polymer GC into the ZPGG0 composite membrane significantly enhances its hydrophilicity due to the high hydroxyl content of GC. The ZPGG1 composite membrane achieves an alkali absorption rate of 98% while maintaining a water contact angle of only 51.4°. With further increases in the GC ratio, the relative content of ZrO2 and the PSU backbone decreases, leading to uneven distribution and aggregation of ZrO2 within the membrane, thus reducing its alkali absorption characteristics.

[0062] (3) The impedance curves of the composite membrane were measured using an electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd. CHI760E). ZPGG0 and ZPGG... 0.5 ZPGG1, ZPGG 1.5 Anion exchange composite membrane (1 cm × 1 cm) was immersed in 30 wt% KOH solution for 24 hours. During measurement, the composite membrane was placed within a polytetrafluoroethylene (PTFE) sandwich structure, with 30 wt% KOH solution injected into its central window to determine the surface resistivity. The scanning frequency range was set from 0.1 to 1,000,000 Hz, and the voltage amplitude was 0.1 V (at room temperature). The bubble point pressure (BBP) of the composite membrane was determined using the bubble point method, referring to GB / T 26204-2010 "Performance Test Methods for Liquid Phase Filter Materials—Air Bubble Point Test". The sample was clamped in the testing apparatus with its bottom surface exposed to air and its top surface immersed in deionized water. An air pump continuously pressurized the membrane until the first bubble formed when gas passed through it, and the bubble point pressure value was recorded.

[0063] like Figure 3 As shown, the ZPGG0 composite film exhibits a low areal resistivity (0.17 Ω cm⁻¹). 2 () Figure 3 (b) This can be attributed to the abundant internal pore structure of ZPGG0, which provides efficient ion transport channels. For example... Figure 3 As shown in Figure a, due to the micro / nanoporous structure of the surface, the ZPGG0 composite membrane achieves a bubble point pressure of 3.6 bar, surpassing the commercially available ZIRFION UTP 500 membrane (3.3 bar). With increased GC incorporation, the higher polymer ratio promotes the formation of a dense polymer network in the composite membrane, thereby significantly improving the bubble point pressure (BPP). The BPP value increases from ZPGG0... 0.5 →ZPGG1→ZPGG 1.5 The ZPGG0 was increased from 3.6 bar to 3.8 bar, then to 3.9 bar, and finally to 4.2 bar.

[0064] (4) The ion exchange capacity (IEC) of the composite membrane was determined by acid-base titration. First, ZPGG0 and ZPGG... 0.5 ZPGG1, ZPGG1.5 A 2cm × 2cm square sample of the anion exchange composite membrane was cut and immersed in a 2M potassium hydroxide solution for 24 hours of ion exchange at room temperature. After removal, it was rinsed with deionized water and dried to constant weight under constant temperature conditions; this weight is denoted as W. d The membrane was then immersed in a 0.01 M hydrochloric acid standard solution, releasing hydroxide ions and neutralizing the acid solution over 24 hours. After removing the membrane, phenolphthalein was added as an indicator, and the remaining HCl solution was titrated to neutral with 0.01 M NaOH solution. Based on the initial molar amount of HCl (M...), the... o, HCl ) and the molar amount of HCl remaining after titration (M) e, HCl The ion exchange capacity (IEC) value was calculated.

[0065] .

[0066] The impedance spectrum of the membrane was determined by electrochemical impedance spectroscopy (EIS) using an electrochemical workstation (CHI760E series, Shanghai CH Instruments). First, the composite membrane sample (1 cm × 1 cm) was subjected to ion exchange in 2 M KOH solution for 24 hours, rinsed with deionized water until neutral, and then clamped in a polytetrafluoroethylene (PTFE) electrolytic cell for measurement. The measurement conditions were set as follows: AC amplitude 0.1 V at room temperature, frequency range 0.1 Hz to 1 MHz. The measured resistance value was converted to anionic conductivity σ (S / cm) according to formula (5). -1 ):

[0067] ;

[0068] Where L is the film thickness (cm) and A is the effective contact area (cm²). 2 R is the resistance (Ω).

[0069] The activation energy (Ea) of the membrane sample was calculated using the Arrhenius equation based on the conductivity data (σ) mentioned above under conditions of 30℃ to 80℃.

[0070] ;

[0071] Where A is the frequency factor, k B Let T(K) be the Boltzmann constant, and T(K) be the absolute temperature.

[0072] like Figure 4 As shown, the composite membrane has multiple cation sites, which can promote OH- in a dense polymer matrix. - Rapid transport of the carrier. Ion exchange capacity tests confirmed the content of exchangeable ions in different composite membranes. Even without quaternary ammonium groups, the ZPGG0 membrane still has an IEC value of 0.13 mequiv·g.-1 ( Figure 4 a) This indicates that the abundant pore structure and hydrophilic functional materials within the membrane can promote partial anchoring of the carrier within the composite membrane. With increasing GC content, the IEC value of the composite membrane significantly improves. The IEC value of the ZPGG1 composite membrane reaches 0.62 mequiv·g. -1 Therefore, cation sites play a crucial role in the transport process. Under pure water conditions, the conductivity of the ZPGG0 composite membrane is 0.29 mS / cm (…). Figure 4 b) Its transmission relies entirely on internal channels. In contrast, ZPGG... X The quaternary ammonium cation sites in the composite membrane can carry OH. - The presence of ions allows it to maintain good conductivity even under pure water conditions. ZPGG1 and ZPGG 1.5 The composite films have similar conductivity values, reaching 2.13 mS·cm. -1 and 2.09 mS·cm -1 This represents an improvement of nearly 10 times compared to the ZPGG0 membrane. Furthermore, Figure 4 c also shows that ZPGG0 exhibits a high activation energy (23.9 kJ·mol⁻¹). -1 However, with the introduction of GC, the carrier can achieve transition transfer through adjacent cation sites, a process that requires no additional energy consumption. Therefore, the higher the cation site density, the lower the transition energy barrier. ZPGG X All composite membranes exhibit low activation energies (<10 kJ·mol⁻¹). -1 The efficiency is much lower than that of the ZPGG0 composite membrane (23.9 kJ·mol⁻¹). -1 Therefore, ZPGG X The composite membrane can achieve dual conduction through two pathways: channel transport and cation site hopping. Figure 4 d).

[0073] (5) The alkaline water electrolysis (AWE) experiment was conducted in a self-assembled zero-gap single cell. Both the cathode and anode used commercial platinum-free metal catalytic electrodes (LAIYANG-X1, nickel-aluminum alloy) with an effective area of ​​4.84 cm². 2 ZPGG0 and ZPGG 0.5 ZPGG1, ZPGG 1.5 An anion exchange composite membrane is sandwiched between two layers of polytetrafluoroethylene (PTFE) insulation, thus achieving separation of the cathode and anode. The entire electrolysis unit is precision assembled and pressure-sealed to ensure ideal operating conditions. The electrolyte (30wt% KOH), after heating, circulates through the battery via a peristaltic pump at a flow rate of 160 mL / min, and the current density is adjusted from 50 mA / cm². 2 →2 000mA / cm2 Measure and record the polarization curves.

[0074] like Figure 5 As shown, the ZPGG0 membrane achieves a high current density (13800 A / m²) at 2V by synergistically regulating the pore structure through a dual-pore pore-forming agent. 2 The optimized pore structure combines excellent porosity with alkali adsorption capacity. After introducing GC, ZPGG... X Due to its superior hydrophilicity, and the presence of cation sites enhancing the conductivity of the composite membrane, the ZPGG1 composite membrane achieved an conductivity of 18900 A / m under 2V trench pressure. 2 High current density > ZPGG 0.5 (16000 A / m) 2 @2 V) and ZPGG 1.5 (17800 A / m) 2 The @2 V) composite membrane is 37% better than ZPGG0.

[0075] (6) Continuous exposure of the composite membrane to a high-temperature electrolyte may lead to polymer degradation and detachment of nanofillers. The ZPGG1 composite membrane was assembled into an electrolytic cell and subjected to an electrolytic temperature of 10000 A / m. 2 Accelerated aging tests were conducted at high current density, with battery voltage recorded hourly. Figure 6 As shown, at 10000 A / m 2 After 480 hours of continuous operation at high current density, the electrolytic cell voltage remained stable, exhibiting only 0.125 mV·h. -1 The ZPGG1 membrane exhibits superior electrochemical performance and stability, further highlighting its potential in practical applications.

Claims

1. A bifunctional ion-conducting anion-exchange composite membrane, characterized in that, The composite membrane is prepared by using alkali-resistant polymers, pore-forming agents, and zirconium dioxide as the basic components of the slurry, followed by the introduction of guar hydroxypropyltrimethylammonium chloride (GC) and coating it onto a support. The pore-forming agents are polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP). The composite membrane achieves an anion exchange membrane with a surface micro / nanoporous structure by employing the synergistic effect of dipole moments induced by dual pore-forming agents and component modulation, while simultaneously introducing cation sites. The composite membrane achieves dual-function OH- ion exchange membranes with pore transport and site hopping after introducing cation sites into the composite system. - Conduction.

2. The bifunctional ion-conducting anion-exchange composite membrane according to claim 1, characterized in that, The alkali-resistant polymer is polysulfone (PSU).

3. The bifunctional ion-conducting anion-exchange composite membrane according to claim 1, characterized in that, The support material is polyphenylene sulfide (PPS).

4. A method for preparing a bifunctional ion-conducting anion-exchange composite membrane as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Dissolve the alkali-resistant polymer in an organic solvent by stirring, then add a pore-forming agent and mix; add zirconium dioxide into the solution, stir evenly and remove bubbles by ultrasonication to obtain a slurry; (2) Disperse guar gum hydroxypropyltrimethylammonium chloride GC in an organic solvent and stir thoroughly. Then add the resulting dispersion system to the above slurry until it is uniformly stirred. (3) The slurry obtained in step (2) is poured onto the support and coated, and then immersed in ethanol for phase inversion to obtain a bifunctional ion-conducting anion-exchange composite membrane.

5. The preparation method according to claim 4, characterized in that, The organic solvent in step (1) is N-methylpyrrolidone (NMP); the mass ratio of the alkali-resistant polymer to the organic solvent is 1:2-10.

6. The preparation method according to claim 4, characterized in that, The porogen in step (1) is polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) in a mass ratio of 1:1; the mass ratio of the porogen to the alkali-resistant polymer is 1:2-4.

7. The preparation method according to claim 4, characterized in that, The mass ratio of the alkali-resistant polymer to zirconium dioxide in step (1) is 1:2-4.

8. The preparation method according to claim 4, characterized in that, The organic solvent in step (2) is N-methylpyrrolidone (NMP); the mass ratio of GC to organic solvent is 1:2-10; the mass ratio of GC to alkali-resistant polymer is 1-3:2-4.

9. The application of a bifunctional ion-conducting anion-exchange composite membrane as described in any one of claims 1-3 in alkaline water electrolysis for hydrogen production.

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