Membrane electrode assembly of anion exchange membrane electrolytic cell and preparation method of membrane electrode assembly

Abstract

The invention relates to the technical field of water electrolysis hydrogen production, in particular to a membrane electrode assembly of an anion exchange membrane electrolytic cell and a preparation method of the membrane electrode assembly. Comprising the following steps: step 1, adding modified titanium dioxide, an epoxy group cross-linking agent and a modified polymer into toluene, and homogenizing; casting by using a phase inversion method, and carrying out cross-linking treatment at 75-85 DEG C for 6-8 hours to obtain an anion exchange membrane; step 2, respectively spraying cathode catalyst slurry and anode catalyst slurry on two sides of the anion exchange membrane, drying and curing to form a cathode catalyst layer and an anode catalyst layer; a cathode protection layer is attached to the surface of the cathode catalyst layer through vacuum adsorption, an anode protection layer is attached to the surface of the anode catalyst layer through vacuum adsorption, and rolling is conducted; therefore, the membrane electrode assembly of the anion exchange membrane electrolytic cell is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by electrolysis of water, and in particular to a membrane electrode assembly of an anion exchange membrane electrolyzer and a preparation method thereof. Background Art

[0002] As the global demand for clean energy continues to grow, hydrogen energy, as a highly potential clean energy carrier, has received widespread attention. In many energy application scenarios, such as hydrogen fuel cell vehicles in the transportation field and hydrogen energy storage devices in distributed power generation systems, there are urgent requirements for the efficient and stable supply of hydrogen energy. Anion exchange membrane electrolyzer (AEMEC) is an efficient and environmentally friendly hydrogen production technology with the advantages of low energy consumption and the use of non-precious metal catalysts. This can not only effectively reduce the cost of hydrogen production, but also reduce dependence on scarce precious metal resources. Therefore, it has become a research hotspot in the field of hydrogen energy preparation.

[0003] In anion exchange membrane electrolyzer, anion exchange membrane undertakes the key task of conducting hydroxide ions and water molecules, which directly affects the ion conductivity and hydrogen production efficiency. From a microscopic perspective, the smoothness of ion conduction is closely related to the chemical structure and physical channels in the membrane. In the prior art, quaternary ammonium cations are often used as cationic groups to combine with polymers to form anion exchange membranes. Due to the relatively large structure of quaternary ammonium cations, the ion transmission performance of such membranes is limited; on the one hand, the chemical stability of anion exchange membranes is poor. Under high alkaline conditions, due to the chemical action of hydroxide ions and anion exchange membranes, long-term use in this environment leads to a decline in overall performance and even polymer main chain breakage and functional group shedding; on the other hand, quaternary ammonium salt ions have strong hydrophilicity and poor crosslinking with other functional groups, which can easily cause swelling of the membrane. This swelling phenomenon can cause the membrane to be dimensionally unstable, and the strength and toughness also decrease, which reduces the durability of application.

[0004] In summary, it is of great significance to solve the above problems and prepare a membrane electrode assembly for an anion exchange membrane electrolyzer. Summary of the invention

[0005] The object of the present invention is to provide a membrane electrode assembly of an anion exchange membrane electrolyzer and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer comprises the following steps:

[0008] Step 1: adding modified titanium dioxide, epoxy crosslinking agent and modified polymer to toluene and homogenizing; casting by phase inversion method, crosslinking treatment at 75-85° C. for 6-8 hours to obtain an anion exchange membrane;

[0009] Step 2: Spray the cathode catalyst slurry and the anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; vacuum adsorb and adhere the cathode protection layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protection layer on the surface of the anode catalyst layer, and roll and press to obtain a membrane electrode assembly.

[0010] The material of the cathode catalyst layer includes but is not limited to one of platinum carbon, nickel-doped platinum carbon, and iron disulfide; the material of the anode catalyst layer includes but is not limited to one of ruthenium carbon, ruthenium dioxide, and iridium dioxide;

[0011] Among them, the cathode protection layer and the anode protection layer are polymer films coated with pressure-sensitive adhesive; the pressure-sensitive adhesive includes but is not limited to acrylic pressure-sensitive adhesive, silicone pressure-sensitive adhesive, rubber pressure-sensitive adhesive; the polymer film includes but is not limited to polyester film and polyolefin film.

[0012] More optimally, in the raw materials of the anion exchange membrane, the mass ratio of modified titanium dioxide, epoxy crosslinking agent, and modified polymer is 1-1.5:0.5-1:3-5.

[0013] More optimally, the preparation process of the modified titanium dioxide is:

[0014] S1-1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% to 50wt% ethanol aqueous solution, adjust the pH to 5.5 to 6.5, stir at 45 to 55°C for 7 to 8 hours, wash and dry to obtain modified titanium dioxide A;

[0015] S1-2: Add modified titanium dioxide A and 1,1,2,3,3-pentamethylguanidine to N,N-dimethylformamide, react at 20-30°C for 18-24 hours, add cysteine ​​and photoinitiator under ultraviolet light, react at 20-40°C for 30-60 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide.

[0016] More optimally, in the raw materials of the modified titanium dioxide A, the mass ratio of nano titanium dioxide, chloromethyltrimethoxysilane, and vinyltriethoxysilane is 1-1.5: 0.05-0.15: 0.1-0.3;

[0017] The raw materials of the modified titanium dioxide include the following components: by mass, 3 to 4 parts of modified titanium dioxide A, 2 to 3 parts of 1,1,2,3,3-pentamethylguanidine, 40 to 50 parts of N,N-dimethylformamide, 1 to 2 parts of cysteine, and 0.05 to 0.1 parts of a photoinitiator.

[0018] More optimally, the preparation process of the modified polymer is:

[0019] S2-1: Under an argon atmosphere, glycidyl acrylate, hexafluorobutyl methacrylate, trifluoropropyl methacrylate, and azobisisobutyronitrile are added to N,N-dimethylformamide, reacted at 55-65° C. for 18-24 hours, washed and dried to obtain a polymer;

[0020] S2-2: Add the polymer and triaminoguanidine hydrochloride into toluene, and react at 75-85° C. for 6-8 hours to obtain a modified polymer.

[0021] More optimally, the raw materials of the modified polymer include the following components: by mass, 2 to 3 parts of glycidyl acrylate, 3 to 4 parts of hexafluorobutyl methacrylate, 2 to 3 parts of trifluoropropyl methacrylate, 0.1 to 0.3 parts of azobisisobutyronitrile, 4 to 7 parts of triaminoguanidine hydrochloride, and 50 to 60 parts of toluene.

[0022] More optimally, the epoxy crosslinking agent includes one of pentaerythritol tetraglycidyl ether, trimethylolpropane triglycidyl ether, polypropylene glycol diglycidyl ether, and bisphenol A diglycidyl ether.

[0023] More optimally, the specific process of the homogenization is: after stirring, ultrasonic dispersion is performed at 200-300 rpm / min for 10-30 min.

[0024] More optimally, in step 2, the specific parameters are: roller pressure is 25-35kg, and vacuum adsorption pressure is 0.5-1Mpa.

[0025] Compared with the prior art, the beneficial effects of the present invention are: by modifying titanium dioxide and modified polymers, cross-linking with epoxy cross-linking agents, a hydrophobic-hydrophilic phase separation is formed, and on the premise of improving ion conductivity, the chemical stability and swelling properties of the anion exchange membrane are effectively improved, thereby improving mechanical strength and increasing application durability.

[0026] In the scheme, guanidine and amino groups are introduced into modified titanium dioxide. Since titanium dioxide itself has a large specific surface area and void structure, high mechanical strength and contains a large number of hydroxyl groups on the surface, after modification, it can provide more active sites and ion transmission channels, enhance ion conductivity, and further improve hydrogen production efficiency; on the one hand, the guanidine group itself has strong alkalinity and high reactivity, and can maintain high chemical stability in a strong alkaline environment. After modification, it can improve the chemical stability of the anion exchange membrane and form ion conduction channels through hydrogen bonds and other effects, further improving the ion conductivity; on the other hand, its introduction can be cross-linked through epoxy cross-linking agents, interact with modified polymers, and form a three-dimensional network structure, which can improve the dispersibility while also improving the swelling properties of the anion exchange membrane and improving the mechanical stability.

[0027] In the scheme, the modified polymer introduces fluorine, guanidine, and amino groups. On the one hand, they form similar compatibility with the guanidine groups in the modified titanium dioxide, improve dispersibility and compatibility, and synergistically improve ion conductivity and chemical stability; on the other hand, the fluorine-containing carbon chain in the polymer has strong hydrophobicity to form a hydrophobic carbon chain skeleton, and the guanidine groups formed by the reaction have hydrophilicity to form a hydrophilic segment. A hydrophilic-hydrophobic phase separation structure is formed, further improving ion conductivity. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that the following parts are by mass, and all raw materials involved in the present invention are purchased from manufacturers without any special restrictions. Examples include: In the following embodiments, 1,1,2,3,3-pentamethylguanidine has a purity of 99%, CAS No. 13439-84-4, purchased from (Alpha) Henan Weitixi Chemical Technology Co., Ltd.; pentaerythritol tetraglycidyl ether has a purity of 99%, CAS No. 3126-63-4; the specification of nano titanium dioxide is 10nm, item No. T818940, purchased from Macklin Reagent; the purity of triaminoguanidine hydrochloride is 98%, and the CAS number is 5329-29-3; the CAS number of the initiator is 24650-42-8; the item number of the acrylic pressure-sensitive adhesive is HS-7262, purchased from Guangzhou Huisheng Technology New Materials Co., Ltd.; the item number of 40% platinum carbon is 25001204-1g; the item number of 40% ruthenium carbon is P20A400, purchased from Beijing Nakaili Technology Co., Ltd.

[0030] In the following embodiments, the material of the cathode catalyst layer is 40% platinum carbon; the material of the anode catalyst layer is 40% ruthenium carbon; the cathode protection layer and the anode protection layer are polymer films coated with pressure-sensitive adhesive; the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive; and the polymer film is polyethylene terephthalate.

[0031] Embodiment 1: A method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer, comprising the following steps:

[0032] Step 1: S1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% ethanol aqueous solution in a mass ratio of 1.2:0.1:0.2, adjust the pH to 6.0, stir at 50°C for 7.5 hours, wash and dry to obtain modified titanium dioxide A; S2: Add 3.5 parts of modified titanium dioxide A and 2.5 parts of 1,1,2,3,3-pentamethylguanidine to 45 parts of N,N-dimethylformamide, react at 25°C for 20 hours, add 1.5 parts of cysteine ​​and 0.08 parts of photoinitiator under ultraviolet light, react at 30°C for 45 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide;

[0033] Step 2: S1: Under argon atmosphere, add 2.5 parts of glycidyl acrylate, 3.5 parts of hexafluorobutyl methacrylate, 2.5 parts of trifluoropropyl methacrylate, and 0.2 parts of azobisisobutyronitrile to N,N-dimethylformamide, react at 60°C for 20 hours, wash and dry to obtain a polymer; S2: add the polymer and 6.2 parts of triaminoguanidine hydrochloride to 55 parts of toluene, react at 80°C for 7 hours to obtain a modified polymer;

[0034] Step 3: S1: Add modified titanium dioxide, pentaerythritol tetraglycidyl ether and modified polymer to toluene in a mass ratio of 1.2:0.8:4.5, stir and ultrasonically disperse at 250 rpm / min for 20 min; use phase inversion method to cast, cross-link at 80°C for 7 hours to obtain an anion exchange membrane; S2: Spray cathode catalyst slurry and anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; set the vacuum pressure to 0.8 MPa, vacuum adsorb and adhere the cathode protective layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protective layer on the surface of the anode catalyst layer, and roll at a pressure of 30 kg to obtain a membrane electrode assembly.

[0035] Embodiment 2: A method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer, comprising the following steps:

[0036] Step 1: S1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% ethanol aqueous solution in a mass ratio of 1.2:0.1:0.2, adjust the pH to 6.0, stir at 50°C for 7.5 hours, wash and dry to obtain modified titanium dioxide A; S2: Add 3.5 parts of modified titanium dioxide A and 2.5 parts of 1,1,2,3,3-pentamethylguanidine to 45 parts of N,N-dimethylformamide, react at 25°C for 20 hours, add 1.5 parts of cysteine ​​and 0.08 parts of photoinitiator under ultraviolet light, react at 30°C for 45 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide;

[0037] Step 2: S1: Under argon atmosphere, add 2.5 parts of glycidyl acrylate, 3.5 parts of hexafluorobutyl methacrylate, 2.5 parts of trifluoropropyl methacrylate, and 0.2 parts of azobisisobutyronitrile to N,N-dimethylformamide, react at 60°C for 20 hours, wash and dry to obtain a polymer; S2: add the polymer and 6.2 parts of triaminoguanidine hydrochloride to 55 parts of toluene, react at 80°C for 7 hours to obtain a modified polymer;

[0038] Step 3: S1: Add modified titanium dioxide, pentaerythritol tetraglycidyl ether and modified polymer to toluene in a mass ratio of 1.2:0.8:4.5, stir and ultrasonically disperse at 250 rpm / min for 20 min; use phase inversion method to cast, cross-link at 80°C for 7 hours to obtain an anion exchange membrane; S2: Spray cathode catalyst slurry and anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; set the vacuum pressure to 0.8 MPa, vacuum adsorb and adhere the cathode protective layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protective layer on the surface of the anode catalyst layer, and roll at a pressure of 30 kg to obtain a membrane electrode assembly.

[0039] Embodiment 3: A method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer, comprising the following steps:

[0040] Step 1: S1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% ethanol aqueous solution in a mass ratio of 1:0.5:3, adjust the pH to 6.0, stir at 50°C for 7.5 hours, wash and dry to obtain modified titanium dioxide A; S2: Add 3.5 parts of modified titanium dioxide A and 2.5 parts of 1,1,2,3,3-pentamethylguanidine to 45 parts of N,N-dimethylformamide, react at 25°C for 20 hours, add 1.5 parts of cysteine ​​and 0.08 parts of photoinitiator under ultraviolet light, react at 30°C for 45 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide;

[0041] Step 2: S1: Under argon atmosphere, add 2.5 parts of glycidyl acrylate, 3.5 parts of hexafluorobutyl methacrylate, 2.5 parts of trifluoropropyl methacrylate, and 0.2 parts of azobisisobutyronitrile to N,N-dimethylformamide, react at 60°C for 20 hours, wash and dry to obtain a polymer; S2: add the polymer and 6.2 parts of triaminoguanidine hydrochloride to 55 parts of toluene, react at 80°C for 7 hours to obtain a modified polymer;

[0042] Step 3: S1: Add modified titanium dioxide, pentaerythritol tetraglycidyl ether and modified polymer to toluene in a mass ratio of 1.5:1:5, stir and ultrasonically disperse at 250 rpm / min for 20 min; use phase inversion method to cast, cross-link at 80°C for 7 hours to obtain an anion exchange membrane; S2: Spray cathode catalyst slurry and anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; set the vacuum pressure to 0.8 MPa, vacuum adsorb and adhere the cathode protective layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protective layer on the surface of the anode catalyst layer, and roll at a pressure of 30 kg to obtain a membrane electrode assembly.

[0043] Comparative Example 1: Based on Example 1, no crosslinking agent is added, and the other processes remain unchanged, specifically:

[0044] Step 1: S1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% ethanol aqueous solution in a mass ratio of 1.2:0.1:0.2, adjust the pH to 6.0, stir at 50°C for 7.5 hours, wash and dry to obtain modified titanium dioxide A; S2: Add 3.5 parts of modified titanium dioxide A and 2.5 parts of 1,1,2,3,3-pentamethylguanidine to 45 parts of N,N-dimethylformamide, react at 25°C for 20 hours, add 1.5 parts of cysteine ​​and 0.08 parts of photoinitiator under ultraviolet light, react at 30°C for 45 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide;

[0045] Step 2: S1: Under argon atmosphere, add 2.5 parts of glycidyl acrylate, 3.5 parts of hexafluorobutyl methacrylate, 2.5 parts of trifluoropropyl methacrylate, and 0.2 parts of azobisisobutyronitrile to N,N-dimethylformamide, react at 60°C for 20 hours, wash and dry to obtain a polymer; S2: add the polymer and 6.2 parts of triaminoguanidine hydrochloride to 55 parts of toluene, react at 80°C for 7 hours to obtain a modified polymer;

[0046] Step 3: S1: Add the modified polymer to N,N-dimethylformamide, add modified titanium dioxide, the mass ratio of the modified polymer to the modified titanium dioxide is 1:5, stir and ultrasonically disperse at 800 rpm / min for 30 minutes, cast by phase inversion method to obtain an anion exchange membrane; S2: Spray the cathode catalyst slurry and the anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; set the vacuum pressure to 0.8 MPa, vacuum adsorb and adhere the cathode protection layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protection layer on the surface of the anode catalyst layer, and roll at a pressure of 30 kg to obtain a membrane electrode assembly.

[0047] Comparative Example 2: Based on Example 1, the quaternary ammonium salt with an amino group is used instead of triaminoguanidine hydrochloride, and the other processes remain unchanged, specifically:

[0048] Step 1: S1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% ethanol aqueous solution in a mass ratio of 1.2:0.1:0.2, adjust the pH to 6.0, stir at 50°C for 7.5 hours, wash and dry to obtain modified titanium dioxide A; S2: Add 3.5 parts of modified titanium dioxide A and 2.5 parts of 1,1,2,3,3-pentamethylguanidine to 45 parts of N,N-dimethylformamide, react at 25°C for 20 hours, add 1.5 parts of cysteine ​​and 0.08 parts of photoinitiator under ultraviolet light, react at 30°C for 45 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide;

[0049] Step 2: S1: Under an argon atmosphere, 2.5 parts of glycidyl acrylate, 3.5 parts of hexafluorobutyl methacrylate, 2.5 parts of trifluoropropyl methacrylate, and 0.2 parts of azobisisobutyronitrile are added to N,N-dimethylformamide, reacted at 60° C. for 20 hours, washed and dried to obtain a polymer; S2: The polymer and 8 parts of (2-aminoethyl)trimethylammonium chloride hydrochloride are added to 55 parts of toluene, reacted at 80° C. for 7 hours to obtain a modified polymer;

[0050] Step 3: S1: Add modified titanium dioxide, pentaerythritol tetraglycidyl ether and modified polymer to toluene in a mass ratio of 1.2:0.8:4.5, stir and ultrasonically disperse at 250 rpm / min for 20 min; use phase inversion method to cast, cross-link at 80°C for 7 hours to obtain an anion exchange membrane; S2: Spray cathode catalyst slurry and anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; set the vacuum pressure to 0.8 MPa, vacuum adsorb and adhere the cathode protective layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protective layer on the surface of the anode catalyst layer, and roll at a pressure of 30 kg to obtain a membrane electrode assembly.

[0051] Comparative Example 3: Based on Example 1, fluorine element is not introduced, and the other processes remain unchanged, specifically:

[0052] Step 1: S1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% ethanol aqueous solution in a mass ratio of 1.2:0.1:0.2, adjust the pH to 6.0, stir at 50°C for 7.5 hours, wash and dry to obtain modified titanium dioxide A; S2: Add 3.5 parts of modified titanium dioxide A and 2.5 parts of 1,1,2,3,3-pentamethylguanidine to 45 parts of N,N-dimethylformamide, react at 25°C for 20 hours, add 1.5 parts of cysteine ​​and 0.08 parts of photoinitiator under ultraviolet light, react at 30°C for 45 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide;

[0053] Step 2: S1: Under an argon atmosphere, 2.5 parts of glycidyl acrylate, 2 parts of methyl acrylate, 2.3 parts of ethyl methacrylate, and 0.2 parts of azobisisobutyronitrile are added to N,N-dimethylformamide, reacted at 60°C for 20 hours, washed and dried to obtain a polymer; S2: The polymer and 6 parts of triaminoguanidine hydrochloride are added to 55 parts of toluene, reacted at 80°C for 7 hours to obtain a modified polymer;

[0054] Step 3: S1: Add modified titanium dioxide, pentaerythritol tetraglycidyl ether and modified polymer to toluene in a mass ratio of 1.2:0.8:4.5, stir and ultrasonically disperse at 250 rpm / min for 20 min; use phase inversion method to cast, cross-link at 80°C for 7 hours to obtain an anion exchange membrane; S2: Spray cathode catalyst slurry and anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; set the vacuum pressure to 0.8 MPa, vacuum adsorb and adhere the cathode protective layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protective layer on the surface of the anode catalyst layer, and roll at a pressure of 30 kg to obtain a membrane electrode assembly.

[0055] Comparative Example 4: Based on Example 1, 1,1,2,3,3-pentamethylguanidine was not introduced, and the other processes remained unchanged, specifically:

[0056] Step 1: S1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% ethanol aqueous solution in a mass ratio of 1.2:0.1:0.2, adjust the pH to 6.0, stir at 50°C for 7.5 hours, wash and dry to obtain modified titanium dioxide A; S2: Under ultraviolet light, add 3.5 parts of modified titanium dioxide A, 1.5 parts of cysteine ​​and 0.08 parts of photoinitiator to 45 parts of N,N-dimethylformamide, react at 30°C for 45 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide;

[0057] Step 2: S1: Under argon atmosphere, add 2.5 parts of glycidyl acrylate, 3.5 parts of hexafluorobutyl methacrylate, 2.5 parts of trifluoropropyl methacrylate, and 0.2 parts of azobisisobutyronitrile to N,N-dimethylformamide, react at 60°C for 20 hours, wash and dry to obtain a polymer; S2: add the polymer and 6.2 parts of triaminoguanidine hydrochloride to 55 parts of toluene, react at 80°C for 7 hours to obtain a modified polymer;

[0058] Step 3: S1: Add modified titanium dioxide, pentaerythritol tetraglycidyl ether and modified polymer to toluene in a mass ratio of 1.2:0.8:4.5, stir and ultrasonically disperse at 250 rpm / min for 20 min; use phase inversion method to cast, cross-link at 80°C for 7 hours to obtain an anion exchange membrane; S2: Spray cathode catalyst slurry and anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; set the vacuum pressure to 0.8 MPa, vacuum adsorb and adhere the cathode protective layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protective layer on the surface of the anode catalyst layer, and roll at a pressure of 30 kg to obtain a membrane electrode assembly.

[0059] Detection experiment: Anion exchange membranes were prepared from Examples 1 to 3 and Comparative Examples 1 to 4, and their performance was tested: Anion exchange membranes were prepared from Examples 1 to 3 and Comparative Examples 1 to 4, and their ion exchange capacity was tested at 30° C., and then immersed in a 6M sodium hydroxide solution for 550 hours, and their ion exchange capacity was tested again to evaluate their effects on ion exchange capacity and alkali resistance; the results are shown in Table 1;

[0060]

[0061] Table 1

[0062] Result analysis: According to the data analysis in Table 1, it can be seen from Examples 1 to 3 that the present application has prepared an anion exchange membrane with high ion conductivity, mechanical strength, and good stability in a strong alkaline environment, among which Example 1 has the best performance. Examples 2 and 3 have adjusted the proportions of modified titanium dioxide, pentaerythritol tetraglycidyl ether, and modified polymer. From the data of Comparative Examples 1 to 4, it can be seen that: from the data of Comparative Example 1, without adding a cross-linking agent, during the strong alkaline immersion process, due to the lack of protection of the cross-linked network, the polymer molecular chain is easily attacked by hydroxide ions and swells, dissolves or degrades, resulting in the loss of ion exchange sites, a decrease in ion exchange capacity, and poor alkali resistance; from the data of Comparative Example 2, it can be seen that when a quaternary ammonium salt with an amino group is used instead of triaminoguanidine hydrochloride, the quaternary ammonium salt with an amino group is easily attacked by hydroxide ions and decomposes, resulting in a decrease in ion exchange sites, thereby reducing the ion exchange capacity and reducing alkali resistance; from the data of Comparative Example 3, it can be seen that without introducing fluorine element, the hydrophobicity of the membrane is reduced, the hydrophilic-hydrophobic phase separation structure is not formed, and the ion conductivity is reduced; from the data of Comparative Example 4, it can be seen that without introducing 1,1,2,3,3-pentamethylguanidine, the compatibility is reduced, the ion exchange capacity is reduced, and the alkali resistance is reduced. It can be concluded that by modifying titanium dioxide and modified polymers and cross-linking with epoxy cross-linking agents to form a hydrophobic-hydrophilic phase separation, the chemical stability and swelling properties of the anion exchange membrane can be effectively improved while improving the ion conductivity, thereby improving the mechanical strength and increasing the application durability.

[0063] 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer, characterized in that: The following steps are involved: Step 1: Add modified titanium dioxide, epoxy crosslinking agent and modified polymer into toluene and homogenize; The anion exchange membrane is obtained by casting using a phase inversion method and cross-linking treatment at 75 to 85° C. for 6 to 8 hours; Step 2: Spray the cathode catalyst slurry and the anode catalyst slurry on both sides of the anion exchange membrane respectively, dry and solidify to form a cathode catalyst layer and an anode catalyst layer; vacuum adsorb and adhere the cathode protection layer on the surface of the cathode catalyst layer, and vacuum adsorb and adhere the anode protection layer on the surface of the anode catalyst layer, and roll and press to obtain a membrane electrode assembly.

2. The method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer according to claim 1, characterized in that: In the raw materials of the anion exchange membrane, the mass ratio of modified titanium dioxide, epoxy crosslinking agent and modified polymer is 1-1.5:0.5-1:3-5.

3. The method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer according to claim 2, characterized in that: The preparation process of the modified titanium dioxide is: S1-1: Add nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane to a 45wt% to 50wt% ethanol aqueous solution, adjust the pH to 5.5 to 6.5, stir at 45 to 55°C for 7 to 8 hours, wash and dry to obtain modified titanium dioxide A; S1-2: Add modified titanium dioxide A and 1,1,2,3,3-pentamethylguanidine to N,N-dimethylformamide, react at 20-30°C for 18-24 hours, add cysteine ​​and photoinitiator under ultraviolet light, react at 20-40°C for 30-60 minutes, centrifuge and wash, and dry to obtain modified titanium dioxide.

4. The method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer according to claim 3, characterized in that: In the raw material of the modified titanium dioxide A, the mass ratio of nano titanium dioxide, chloromethyltrimethoxysilane and vinyltriethoxysilane is 1-1.5:0.05-0.15:0.1-0.3; The raw materials of the modified titanium dioxide include the following components: by mass, 3 to 4 parts of modified titanium dioxide A, 2 to 3 parts of 1,1,2,3,3-pentamethylguanidine, 40 to 50 parts of N,N-dimethylformamide, 1 to 2 parts of cysteine, and 0.05 to 0.1 parts of a photoinitiator.

5. The method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer according to claim 2, characterized in that: The preparation process of the modified polymer is: S2-1: Under an argon atmosphere, glycidyl acrylate, hexafluorobutyl methacrylate, trifluoropropyl methacrylate, and azobisisobutyronitrile are added to N,N-dimethylformamide, reacted at 55-65° C. for 18-24 hours, washed and dried to obtain a polymer; S2-2: Add the polymer and triaminoguanidine hydrochloride into toluene, and react at 75-85° C. for 6-8 hours to obtain a modified polymer.

6. The method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer according to claim 5, characterized in that: The raw materials of the modified polymer include the following components: by mass, 2 to 3 parts of glycidyl acrylate, 3 to 4 parts of hexafluorobutyl methacrylate, 2 to 3 parts of trifluoropropyl methacrylate, 0.1 to 0.3 parts of azobisisobutyronitrile, 4 to 7 parts of triaminoguanidine hydrochloride, and 50 to 60 parts of toluene.

7. The method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer according to claim 2, characterized in that: The epoxy crosslinking agent includes one of pentaerythritol tetraglycidyl ether, trimethylolpropane triglycidyl ether, polypropylene glycol diglycidyl ether, and bisphenol A diglycidyl ether.

8. The method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer according to claim 1, characterized in that: The specific process of the homogenization is: after stirring, ultrasonic dispersion is performed at 200-300 rpm / min for 10-30 minutes.

9. The method for preparing a membrane electrode assembly of an anion exchange membrane electrolyzer according to claim 1, characterized in that: In step 2, the specific parameters are: roller pressure is 25-35 kg, and vacuum adsorption pressure is 0.5-1 MPa.

10. A membrane electrode assembly for an anion exchange membrane electrolyzer, characterized in that: Prepared by the method described in any one of claims 1 to 9.

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