Porous anion exchange membrane based on polyarylpiperidine and preparation method
By using a non-porous anion exchange membrane based on polyaryl piperidine in fuel cells, combining functionalized inorganic nanomaterials and epoxy resin-based crosslinking agents, and preparing through hot press densification process, the problem of degradation of traditional membrane performance during high efficiency operation is solved, and the membrane performance with high efficiency, stability and long life is achieved.
Patent Information
- Application Number
- CN202510450951.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2025-05-13
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The performance of traditional anion exchange membranes decreases when operating at high efficiency, especially under alkaline conditions, their ionic conductivity is low, gas barrier properties are poor, and their mechanical properties and durability need to be improved.
A non-porous anion exchange membrane based on polyaryl piperidine (PAP) was used to combine polyaryl piperidine with functionalized inorganic nanomaterials and epoxy resin-based crosslinking agents, and prepared by in-situ crosslinking and hot press densification process to form a dense non-porous membrane.
The coordinated optimization of high ionic conductivity, low gas permeability, excellent mechanical properties and long life is achieved, and the efficiency and stability of fuel cells are improved.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of ion exchange membranes, and in particular to a non-porous anion exchange membrane based on polyaryl piperidine and a preparation method thereof. Background Art
[0002] With the rapid development of new energy technologies, fuel cells, as an efficient and clean energy conversion device, have received extensive attention. In fuel cell technology, anion exchange membranes are core components, and their performance directly affects the efficiency and stability of the entire battery. Traditional anion exchange membranes mostly use ionomer materials, such as perfluorosulfonic acid ionomers, which have good chemical stability and mechanical properties, but also have some significant disadvantages.
[0003] The ionic conductivity of traditional ionomer membranes is low, especially under alkaline conditions, where their performance drops significantly, limiting the performance of fuel cells when operating at high efficiency. Secondly, the gas barrier properties of such membrane materials are poor, resulting in a high permeability of fuel gases (such as hydrogen), thereby reducing the energy conversion efficiency of the battery. In addition, the mechanical properties and durability of traditional ionomer membranes need to be improved, especially under high temperature and high humidity conditions, where problems such as swelling and deformation are prone to occur, affecting the long-term stability of the battery.
[0004] In order to overcome the shortcomings of traditional ionomer membranes, researchers have tried to develop new anion exchange membrane materials. In recent years, composite membranes based on polyarylpiperidine (PAP) have gradually become a research hotspot due to their unique structure and performance. PAP has high alkaline stability, and its piperidine ring structure can effectively resist the attack of OH⁻. At the same time, by introducing functionalized inorganic nanomaterials, the mechanical properties and gas barrier properties of the membrane can be significantly enhanced. However, there are still deficiencies in the existing technology for the preparation process and performance optimization of PAP-based composite membranes, especially in achieving the synergistic optimization of high ionic conductivity, low gas permeability and long life, which still needs further exploration. Summary of the invention
[0005] In order to solve the problems in the related art, the embodiments of the present disclosure provide a polyaryl piperidine non-porous anion exchange membrane and a preparation method and application thereof.
[0006] In a first aspect, the present disclosure provides a non-porous anion exchange membrane based on polyaryl piperidine, which is composed of the following components in percentage by mass: 50%-85% of polyaryl piperidine, wherein the main chain of the polyaryl piperidine is an aromatic polymer containing a bipiperidine ring, and the piperidine ring is covalently connected to the aromatic ring skeleton through a nucleophilic polycondensation reaction; 5%-30% of functionalized inorganic nanomaterials, whose surfaces are modified with active groups; Epoxy resin crosslinking agent 5%-20%, which contains at least two epoxy groups; The non-porous anion exchange membrane is prepared by in-situ cross-linking and hot pressing densification process, and the hot pressing densification process parameters are temperature 180-200° C., pressure 300-500 bar, and time 5-10 minutes.
[0007] According to an embodiment of the present disclosure, the main chain of the polyaryl piperidine may contain a branched structure, wherein the branch is a C1-C6 alkyl or aryl substituent, and the molar fraction of the branch substituent does not exceed 30% of the total number of aromatic rings in the main chain.
[0008] According to an embodiment of the present disclosure, the functionalized inorganic nanomaterial is selected from silicon dioxide, aluminum oxide, titanium dioxide or silicon nitride nanowires, nanoparticles or nanosheets whose surfaces are modified with amino, hydroxyl or carboxyl groups.
[0009] According to an embodiment of the present disclosure, the epoxy resin cross-linking agent is selected from one or more of ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and diglycidyl tetramethyl cyclohexane dicarboxylate.
[0010] According to an embodiment of the present disclosure, the hot pressing densification process is carried out in an inert gas atmosphere, and the inert gas is selected from one or both of nitrogen and argon.
[0011] According to an embodiment of the present disclosure, the non-porous anion exchange membrane has a dense non-porous structure and a thickness ranging from 50 to 200 microns.
[0012] In a second aspect, the present disclosure provides a method for preparing a non-porous anion exchange membrane as described in any one of the first aspects, comprising the following steps: Mix according to the ratio: dissolve 50%-85% of polyaryl piperidine, 5%-30% of functionalized inorganic nanomaterials and 5%-20% of cross-linking agent in a low-toxic solvent to form a uniform casting solution; Coating and pre-curing: After coating the casting solution on the substrate, evaporate the solvent under the gradient temperature condition of 40-80℃ to form a precursor film; Hot pressing densification: The precursor membrane is hot pressed at 180-200°C and 300-500 bar for 5-10 minutes to obtain a non-porous anion exchange membrane.
[0013] According to an embodiment of the present disclosure, the low-toxicity solvent is one or more of cyclopentanone, cyclohexanone or γ-butyrolactone, and the solid content of the casting solution is 15%-30%.
[0014] According to an embodiment of the present disclosure, the coating method is blade coating, casting or spray coating.
[0015] According to an embodiment of the present disclosure, the hot pressing densification process further includes a post-processing step: vacuum drying at 80-100° C. for 2-4 hours.
[0016] The technical effects provided by the embodiments of the present disclosure may include the following beneficial effects: According to the technical solution provided by the embodiment of the present disclosure, the nonporous anion exchange membrane based on polyaryl piperidine is composed of the following components in mass percentage: 50%-85% polyaryl piperidine, the main chain of the polyaryl piperidine is an aromatic polymer containing a bipiperidine ring, and the piperidine ring is covalently connected to the aromatic ring skeleton through a nucleophilic polycondensation reaction; 5%-30% functionalized inorganic nanomaterials, whose surface is modified with active groups; 5%-20% epoxy resin crosslinking agent, which contains at least two epoxy groups; the nonporous anion exchange membrane is prepared by in-situ crosslinking and hot pressing densification process, and the hot pressing densification process parameters are temperature 180-200℃, pressure 300-500 bar, and time 5-10 minutes. In the above technical solution, polyaryl piperidine containing bipiperidine rings is used as the main chain material, combined with the reinforcing effect of functionalized inorganic nanomaterials and the crosslinking network construction of epoxy resin crosslinking agents, and the synergistic optimization of high ionic conductivity, ultra-low gas permeability, excellent mechanical properties and long life is successfully achieved. At the same time, the preparation process uses low-toxic or non-toxic solvents, meets environmental protection requirements, and shows good process flexibility and adaptability by adjusting materials and process parameters. This comprehensive performance improvement provides important material support for the development of fuel cell technology and promotes the advancement of new energy technology.
[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. DETAILED DESCRIPTION
[0018] The present invention is further described below by way of examples, but it is to be understood that these specific examples will not limit the scope of the present invention in any way. It should be noted that, unless otherwise specified, the raw materials used in the following examples are all commercially available products. Example
[0019] In this example, a non-porous anion exchange membrane based on polyarylpiperidine (PAP) was prepared. The specific operation is as follows: 15 g of polyarylpiperidine (PAP, main chain containing bipiperidine ring, IEC=2.8 mmol / g, Mn=50 kDa), 3 g of functionalized silica nanowires (SiO2-NH2, diameter 20 nm, aspect ratio>50) and 2 g of ethylene glycol diglycidyl ether (EGDGE) were dissolved in 30 g of cyclopentanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature increase of 40-80°C to form a precursor film. The precursor film was hot pressed at 180°C and 400 bar for 5 minutes to obtain a non-porous anion exchange membrane with a thickness of 80 μm. Example
[0020] This example prepares a non-porous anion exchange membrane containing branched polyaryl piperidine (PAP). The specific operation is as follows: 16 g of polyarylpiperidine containing methyl branches (PAP, main chain containing bipiperidine ring, IEC=2.8 mmol / g, Mn=50kDa, molar fraction of branching is 10%), 2.5 g of functionalized silica nanowires (SiO2-NH2) and 1.5 g of ethylene glycol diglycidyl ether (EGDGE) were dissolved in 30 g of cyclopentanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature increase of 40-80°C to form a precursor film. The precursor film was hot pressed at 190°C and 450 bar for 6 minutes to obtain a non-porous anion exchange membrane with a thickness of 80 μm. Example
[0021] In this example, functionalized alumina nanofibers (Al2O3-NH2) are used to replace SiO2-NH2 to prepare a non-porous anion exchange membrane. The specific operation is as follows: 15 g polyaryl piperidine (PAP), 3 g functionalized alumina nanofibers (Al2O3-NH2, diameter 20 nm, aspect ratio>50) and 2 g ethylene glycol diglycidyl ether (EGDGE) were dissolved in 30 g cyclopentanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature increase of 40-80°C to form a precursor film. The precursor film was hot pressed at 180°C and 400 bar for 5 minutes to obtain a non-porous anion exchange membrane with a thickness of 80 μm. Example
[0022] In this example, polyethylene glycol diglycidyl ether (PEGDA) was used instead of EGDGE to prepare a non-porous anion exchange membrane. The specific operation is as follows: 15 g of polyaryl piperidine (PAP), 3 g of functionalized silica nanowires (SiO2-NH2) and 2 g of polyethylene glycol diglycidyl ether (PEGDA) were dissolved in 30 g of cyclopentanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature increase of 40-80°C to form a precursor film. The precursor film was hot-pressed at 180°C and 400 bar for 5 minutes to obtain a non-porous anion exchange membrane with a thickness of 80 μm. Example
[0023] In this embodiment, a non-porous anion exchange membrane is prepared by hot pressing and densification process in a nitrogen atmosphere. The specific operation is as follows: 15 g of polyaryl piperidine (PAP), 3 g of functionalized silica nanowires (SiO2-NH2) and 2 g of ethylene glycol diglycidyl ether (EGDGE) were dissolved in 30 g of cyclopentanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature increase of 40-80°C to form a precursor film. The precursor film was hot-pressed at 180°C and 400 bar for 5 minutes. The entire hot-pressing process was carried out in a nitrogen atmosphere to obtain a non-porous anion exchange membrane with a thickness of 80 μm. Example
[0024] In this embodiment, a non-porous anion exchange membrane with a thickness of 150 μm is prepared. The specific operation is as follows: 15 g of polyaryl piperidine (PAP), 3 g of functionalized silica nanowires (SiO2-NH2) and 2 g of ethylene glycol diglycidyl ether (EGDGE) were dissolved in 30 g of cyclopentanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature increase of 40-80°C to form a precursor film. The precursor film was hot-pressed at 180°C and 400 bar for 10 minutes to obtain a non-porous anion exchange membrane with a thickness of 150 μm. Example
[0025] This example describes in detail the complete preparation method of non-porous anion exchange membrane. The specific operation is as follows: 15 g of polyaryl piperidine (PAP), 3 g of functionalized silica nanowires (SiO2-NH2) and 2 g of ethylene glycol diglycidyl ether (EGDGE) were dissolved in 30 g of cyclopentanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature increase of 40-80°C to form a precursor film. The precursor film was hot-pressed at 180°C and 400 bar for 5 minutes to obtain a non-porous anion exchange membrane with a thickness of 80 μm. Example
[0026] In this example, cyclohexanone is used instead of cyclopentanone as the solvent to prepare a non-porous anion exchange membrane. The specific operation is as follows: 15 g of polyaryl piperidine (PAP), 3 g of functionalized silica nanowires (SiO2-NH2) and 2 g of ethylene glycol diglycidyl ether (EGDGE) were dissolved in 30 g of cyclohexanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature increase of 40-80°C to form a precursor film. The precursor film was hot-pressed at 180°C and 400 bar for 5 minutes to obtain a non-porous anion exchange membrane with a thickness of 80 μm.
[0027] This comparative example uses a commercially available perfluorosulfonic acid ionomer membrane (Nafion 117) for performance comparison.
[0028] This comparative example omits the cross-linking step. The specific operation is as follows: 15 g of polyaryl piperidine (PAP) and 3 g of functionalized silica nanowires (SiO2-NH2) were dissolved in 30 g of cyclopentanone to form a solution with a solid content of 20%. The solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature of 40-80°C to form a precursor film. The precursor film was hot-pressed at 180°C and 400 bar for 5 minutes to obtain a film with a thickness of 80 μm, but no cross-linking treatment was performed.
[0029] This comparative example omits the hot pressing densification step. The specific operation is as follows: 15 g of polyaryl piperidine (PAP), 3 g of functionalized silica nanowires (SiO2-NH2) and 2 g of ethylene glycol diglycidyl ether (EGDGE) were dissolved in 30 g of cyclopentanone to form a uniform casting solution with a solid content of 20%. The casting solution was coated on a glass substrate with a thickness of 300 μm. The solvent was evaporated under a gradient temperature condition of 40-80°C to form a precursor film, but no hot pressing densification treatment was performed.
[0030] Performance Test Method Description Surface resistance test: The surface resistance of the membrane was measured in 1 M KOH solution using an electrochemical workstation (Autolab PGSTAT302N).
[0031] Gas permeability test: A gas permeameter (Permeatech 8000) was used to measure the permeability of H2 in the membrane.
[0032] Tensile strength test: The tensile strength of the films was measured using a universal testing machine (Instron 5966).
[0033] Swelling rate test: After immersing in 6M KOH solution for 24 hours, the thickness change of the membrane was measured.
[0034] Flexibility test: The elongation at break is used to characterize the flexibility of the film.
[0035] Life test: Accelerated life test was performed at 80°C and 6M KOH, and the performance degradation was recorded.
[0036] The test results of the surface resistance, H2 permeability, tensile strength, swelling ratio, elongation at break and 80°C life of the above-mentioned Examples 1-8 and Comparative Examples 1-3 are shown in the following table:
[0037] Results analysis: Example 1 is used as the basic solution, and all performance indicators are better than the comparative example. Example 2 further optimizes the performance by introducing branched PAP, reducing the surface resistance to 0.048 Ω·cm² and the H2 permeability to 2.8×10⁻ 9 mol / (cm²·s), the tensile strength increased to 78 MPa, the elongation at break increased to 26%, and the life at 80°C was extended to more than 26,000 hours. This shows that the introduction of the branched structure helps to improve the conductivity and mechanical properties of the membrane. Example 3 uses functionalized alumina nanofibers to replace SiO2-NH2. Although the surface resistance increases slightly to 0.054 Ω·cm², the H2 permeability increases to 3.4×10⁻ 9 mol / (cm²·s), but the tensile strength remains at 77 MPa, the swelling rate is 5%, the elongation at break is 24%, and the life at 80°C is greater than 24,000 hours. The overall performance is still better than the comparative example. Example 4 uses polyethylene glycol diglycidyl ether (PEGDA) instead of EGDGE, the surface resistance is 0.053 Ω·cm², and the H2 permeability is 3.3×10⁻ 9mol / (cm²·s), tensile strength of 77 MPa, swelling rate of 5%, elongation at break of 25%, and life of more than 25,000 hours at 80°C. This shows that the choice of crosslinking agent has a significant effect on membrane performance, but alternative crosslinking agents can still maintain good overall performance. Example 5 was hot-pressed in a nitrogen atmosphere, and the surface resistance was reduced to 0.049 Ω·cm² and the H2 permeability was reduced to 2.9×10⁻ 9 mol / (cm²·s), the tensile strength increased to 79 MPa, the swelling rate decreased to 4.2%, the elongation at break increased to 27%, and the life at 80°C was extended to more than 28,000 hours. This shows that the inert gas atmosphere helps to improve the stability and flexibility of the membrane. Example 6 By extending the hot pressing time, a membrane with a thickness of 150 μm was successfully prepared with a surface resistance of 0.052 Ω·cm² and a H2 permeability of 3.1×10⁻ 9 mol / (cm²·s), tensile strength of 76 MPa, swelling rate of 5%, elongation at break of 26%, and life of more than 25,000 hours at 80°C. This shows that the adjustment of hot pressing time can meet the requirements of different thicknesses while maintaining good performance. Examples 7 and 8 respectively verify the integrity of the preparation method and the feasibility of solvent substitution, and the performance is comparable to that of Example 1, indicating the stability and adaptability of the process. Comparative Example 1 (conventional ionomer membrane) has a surface resistance of up to 0.08 Ω·cm² and a H2 permeability of 5×10⁻ 8 mol / (cm²·s), tensile strength is only 42 MPa, swelling rate is 12%, elongation at break is 15%, and life at 80°C is only 12,000 hours, all of which are significantly lower than those in the examples. This shows that conventional ionomer membranes have obvious deficiencies in conductivity, gas barrier properties, and mechanical properties. After omitting the cross-linking step in Comparative Example 2, the surface resistance increased to 0.07 Ω·cm², and the H2 permeability increased to 4×10⁻ 8 mol / (cm²·s), the tensile strength was reduced to 38 MPa, the swelling rate was as high as 15%, the elongation at break was 18%, and the life span at 80°C was only 8,000 hours. This shows that cross-linking treatment is crucial to improving the stability and mechanical properties of the membrane. After omitting the hot pressing densification step in comparative example 3, the surface resistance was 0.06 Ω·cm² and the H2 permeability was 3.5×10⁻ 8 mol / (cm²·s), tensile strength of 40 MPa, swelling rate of 10%, elongation at break of 20%, and life of 10,000 hours at 80°C. Although some properties are better than those of comparative example 2, they are still significantly lower than those of the embodiment, indicating that the hot pressing densification step is crucial to achieving high-performance membranes.
[0038] In general, the present invention successfully achieves the preparation of a highly stable nonporous anion exchange membrane through reasonable material selection and process optimization. By comparing the performance data of the embodiments and comparative examples, it can be clearly seen that the scheme of the present invention has significant advantages in conductivity, gas barrier properties, mechanical properties and durability, and has broad application prospects.
[0039] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present disclosure is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present disclosure (but not limited to) by each other.
Claims
1. A nonporous anion exchange membrane based on polyaryl piperidine, characterized in that: It is composed of the following components in percentage by mass: 50%-85% of polyaryl piperidine, wherein the main chain of the polyaryl piperidine is an aromatic polymer containing a bipiperidine ring, and the piperidine ring is covalently connected to the aromatic ring skeleton through a nucleophilic polycondensation reaction; 5%-30% of functionalized inorganic nanomaterials, whose surfaces are modified with active groups; Epoxy resin crosslinking agent 5%-20%, which contains at least two epoxy groups; The non-porous anion exchange membrane is prepared by in-situ cross-linking and hot pressing densification process, and the hot pressing densification process parameters are temperature 180-200° C., pressure 300-500 bar, and time 5-10 minutes.
2. The nonporous anion exchange membrane according to claim 1, characterized in that: The main chain of the polyaryl piperidine may contain a branched structure, wherein the branch is a C1-C6 alkyl or aryl substituent, and the molar fraction of the branch substituent does not exceed 30% of the total number of aromatic rings in the main chain.
3. The nonporous anion exchange membrane according to claim 1 or 2, characterized in that: The functionalized inorganic nanomaterial is selected from silicon dioxide, aluminum oxide, titanium dioxide or silicon nitride nanowires, nanoparticles or nanosheets whose surfaces are modified with amino, hydroxyl or carboxyl groups.
4. The nonporous anion exchange membrane according to any one of claims 1 to 3, characterized in that: The epoxy resin crosslinking agent is selected from one or more of ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and diglycidyl tetramethyl cyclohexane dicarboxylate.
5. The nonporous anion exchange membrane according to claim 1, characterized in that: The hot pressing densification process is carried out in an inert gas atmosphere, and the inert gas is selected from one or both of nitrogen and argon.
6. The nonporous anion exchange membrane according to claim 1, characterized in that: The non-porous anion exchange membrane has a dense non-porous structure and a thickness ranging from 50 to 200 microns.
7. A method for preparing a non-porous anion exchange membrane according to any one of claims 1 to 6, characterized in that: The following steps are involved: Mix according to the ratio: dissolve 50%-85% of polyaryl piperidine, 5%-30% of functionalized inorganic nanomaterials and 5%-20% of cross-linking agent in a low-toxic solvent to form a uniform casting solution; Coating and pre-curing: After coating the casting solution on the substrate, evaporate the solvent under the gradient temperature condition of 40-80℃ to form a precursor film; Hot pressing densification: The precursor membrane is hot pressed at 180-200°C and 300-500 bar for 5-10 minutes to obtain a non-porous anion exchange membrane.
8. The preparation method according to claim 7, characterized in that: The low-toxicity solvent is one or more of cyclopentanone, cyclohexanone or γ-butyrolactone, and the solid content of the casting solution is 15%-30%.
9. The preparation method according to claim 7 or 8, characterized in that: The coating method is blade coating, casting or spray coating.
10. The preparation method according to claim 7, characterized in that: The hot pressing densification process also includes a post-treatment step: vacuum drying at 80-100° C. for 2-4 hours.