Durable perfluorosulfonic acid proton exchange membrane, method of making and use thereof
By introducing hindered phenolic antioxidants into perfluorosulfonic acid proton exchange membranes, the problem of chemical degradation of membranes in fuel cells was solved, and the durability and performance of the membranes were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGNAN UNIV
- Filing Date
- 2023-07-12
- Publication Date
- 2026-06-19
AI Technical Summary
In the prior art, the perfluorosulfonic acid proton exchange membrane prepared in the prior art is easily attacked by hydrogen peroxide radicals and hydroxyl radicals during fuel cell operation, leading to chemical degradation and affecting the membrane's durability and battery performance.
Introducing hindered phenolic antioxidants into perfluorosulfonic acid proton exchange membranes reduces chemical degradation and improves membrane durability by binding with free radicals.
It effectively reduces the chemical degradation rate of perfluorosulfonic acid proton exchange membranes, extends membrane lifespan, and maintains high proton conductivity and mechanical properties while reducing costs.
Abstract
Description
Technical Field
[0001] This invention relates to a durable perfluorosulfonic acid proton exchange membrane, its preparation method, and its application, belonging to the field of ion exchange membrane technology. Background Technology
[0002] Against the backdrop of global concern over environmental issues, the use of fossil fuels is gradually decreasing, and the development of clean new energy sources has become a major direction of development in recent years. Hydrogen energy is undoubtedly one of the most promising new energy sources, and proton exchange membrane fuel cells (PEMFCs) using hydrogen as fuel have become a research focus for many researchers due to their advantages such as high energy density and zero pollution. The proton exchange membrane plays the role of transporting protons while isolating gases and electrons on both sides of the anode and cathode. Therefore, it needs to have high proton conductivity and good gas barrier properties. As a commercially available proton exchange membrane, perfluorosulfonic acid (PFSA) not only possesses the above characteristics, but also has excellent mechanical properties. Kangwei Xu et al. (Journal of Membrane Science, 2022, (655): 120594) pointed out that although PFSA has advantages such as high proton conductivity, good mechanical properties, and strong gas barrier properties, under harsh fuel cell operating conditions, PFSA membranes still suffer significant chemical degradation due to the attack of ether groups, tertiary carbons, and CS bonds in the main chain and side chains of the polymer electrolyte membrane by hydrogen peroxide radicals (HOO·) or hydroxyl radicals (HO·). This leads to the generation of bubbles and tearing in PEMs, further resulting in battery performance loss and shortened lifespan. Therefore, reducing the chemical degradation of proton exchange membranes is a crucial issue. Summary of the Invention
[0003] The purpose of this invention is to provide a durable perfluorosulfonic acid proton exchange membrane. Hindered phenols are phenolic antioxidants, but due to their unique steric hindrance, the hydrogen on the phenolic hydroxyl group is more easily lost and combines with free radicals, thus exerting a more efficient effect than ordinary phenolic antioxidants, while avoiding the drawbacks of decreased conductivity and migration caused by inorganic free radical scavengers. The durable perfluorosulfonic acid proton exchange membrane provided by this invention, while retaining high proton conductivity and high mechanical properties, extends the service life of the proton exchange membrane at a low cost.
[0004] The technical solution of this invention:
[0005] A durable perfluorosulfonic acid proton exchange membrane, wherein the durable perfluorosulfonic acid proton exchange membrane comprises a hindered phenolic antioxidant and a perfluorosulfonic acid resin, and has a thickness of 5-50 μm; wherein the hindered phenolic antioxidant is one or a mixture of two or more of the following: 3,5-di-tert-butyl-4-hydroxybenzoic acid, 4,4'-thiobis(6-tert-butyl-3-methylphenol), 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 2,6-di-tert-butyl-4-hydroxymethylphenol, α-tocopherol, 2-tert-butylhydroquinone, tert-butyl-4-hydroxyanisole, and 2,6-di-tert-butyl-p-cresol.
[0006] A method for preparing a durable perfluorosulfonic acid proton exchange membrane, wherein the durable perfluorosulfonic acid proton exchange membrane is obtained by solution blending of hindered phenolic antioxidant and perfluorosulfonic acid resin to form a film.
[0007] Furthermore, the preparation method includes the following steps:
[0008] (1) Mix the hindered phenolic antioxidant with the perfluorosulfonic acid resin solution evenly, form a film and then dry it;
[0009] (2) The perfluorosulfonic acid composite proton exchange membrane containing hindered phenol antioxidant obtained in step (1) is placed in a vacuum drying oven for heat treatment.
[0010] (3) The heat-treated composite proton exchange membrane containing hindered phenol antioxidant obtained in step (2) is immersed in sulfuric acid solution for acidification treatment, and then washed and dried with deionized water to obtain a clean and durable perfluorosulfonic acid proton exchange membrane.
[0011] Furthermore, the solid content in the perfluorosulfonic acid resin solution is 1–30 wt%, the amount of hindered phenolic antioxidant added is 0.1–5 wt% of the mass of the perfluorosulfonic acid resin, and the viscosity of the perfluorosulfonic acid resin solution is 2.4–700 cps.
[0012] Furthermore, in step (1), the mixing method of the durable perfluorosulfonic acid proton exchange membrane is one or a combination of two or more of the following: mechanical stirring, magnetic stirring, ultrasonic oscillation, high-speed shearing or cell disruption; the film formation method is spraying, scraping, casting, pouring, spin coating or impregnation.
[0013] Furthermore, in step (1), the drying temperature is 60-80℃ and the drying time is 8-24h.
[0014] Furthermore, in step (2), the heat treatment temperature is 120-160℃ and the heat treatment time is 2-6h.
[0015] Furthermore, in step (2), the concentration of the sulfuric acid solution is 0.1-1 mol / L, the treatment temperature is 60-90℃, and the treatment time is 1-3h; the temperature of the deionized water treatment is 60-90℃, and the treatment time is 1-3h.
[0016] Furthermore, in step (3), the drying temperature is 60-80℃ and the drying time is 8-24h.
[0017] The durable perfluorosulfonic acid proton exchange membrane described above can be applied in fuel cells and water electrolysis for hydrogen production.
[0018] The beneficial effects of this invention are as follows:
[0019] (1) The present invention introduces hindered phenol antioxidant as a free radical scavenger into perfluorosulfonic acid resin, which has good compatibility. Due to the special phenolic hydroxyl structure of hindered phenol, it can effectively remove hydroxyl free radicals that attack the proton exchange membrane during fuel cell operation and improve the long-term durability of the proton exchange membrane.
[0020] (2) Introducing hindered phenols into perfluorosulfonic acid resin will not change its original structure, and due to the small amount added, it has little impact on other aspects of the performance of the proton exchange membrane.
[0021] (3) The preparation process of this invention is safe and simple to operate, low in cost, highly repeatable, and easy to achieve large-scale production. Detailed Implementation
[0022] The present invention will be further described in detail below with reference to the embodiments, but the scope of the present invention is not limited by these embodiments.
[0023] Example 1
[0024] The preparation method of durable perfluorosulfonic acid proton exchange membrane is as follows: (1) Take 10 mL of perfluorosulfonic acid resin solution with a concentration of 30 wt%, weigh 0.003 g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid according to 0.1% of the solid content of the solution and add it to the resin solution. After cell pulverization treatment for 15 min, stir magnetically for 12 h. (2) The uniformly mixed solution is uniformly formed on a glass plate with a PTFE film laid flat by slit extrusion. Then it is placed at 80℃ under normal pressure for 16 h and then heat-treated at 160℃ in a vacuum environment for 2 h. (3) After cooling, take out the heat-treated film, demold it and put it into a 1M sulfuric acid solution at 90℃ for acid treatment for 3 h, then put it into deionized water at the same temperature for 3 h, take it out and dry it at 80℃ for 24 h to obtain a 35 μm thick membrane. Durable perfluorosulfonic acid proton exchange membrane 1 .
[0025] Example 2
[0026] The preparation method of durable perfluorosulfonic acid proton exchange membrane is as follows: (1) Take 5 mL of perfluorosulfonic acid resin solution with a concentration of 20 wt%, weigh 0.01 g of 3,5-di-tert-butyl-4-hydroxybenzoic acid according to 1% of the resin solid content in the solution and add it to the resin solution. After ultrasonic treatment for 30 min, continue magnetic stirring for 8 h. (2) Take 1 mL of the well mixed solution and pour it onto a glass plate with a PTFE film laid flat for scraping. Then place it under normal pressure and dry at 70℃ for 12 h. Transfer it to a vacuum environment and heat treat at 140℃ for 3 h. (3) After cooling, take out the heat-treated film, demold it and put it into a 1M sulfuric acid solution at 80℃ for acid treatment for 1.5 h. Then put it into deionized water at the same temperature for 1.5 h. Take it out and dry it at 80℃ for 12 h to obtain a 25 μm thick membrane. Durable perfluorosulfonic acid proton exchange membrane 2 .
[0027] Example 3
[0028] The preparation method of durable perfluorosulfonic acid proton exchange membrane is as follows: (1) Take 10 mL of perfluorosulfonic acid resin solution with a concentration of 1 wt%, weigh 0.002 g of 2-tert-butylhydroquinone according to 2% of the solid content of the solution and add it to the resin solution. After high-speed shearing for 15 min, stir magnetically for 12 h. (2) Spray the uniformly mixed solution onto a clean glass plate, and then dry it at 60℃ under normal pressure for 24 h. Then heat-treat it in a vacuum environment at 120℃ for 6 h. (3) After cooling, immerse the glass plate in clean deionized water for 15 min, remove the heat-treated membrane, put the membrane into a 0.1 M sulfuric acid solution at 60℃ for acid treatment for 3 h, and then put it into deionized water at the same temperature for 3 h. Take it out and dry it at 60℃ for 24 h to obtain a membrane with a thickness of 10 μm. Durable perfluorosulfonic acid proton exchange membrane 3 .
[0029] Example 4
[0030] The preparation method of durable perfluorosulfonic acid proton exchange membrane is as follows: (1) Take 10 mL of perfluorosulfonic acid resin solution with a concentration of 10 wt%, weigh 0.03 g of 4,4'-thiobis(6-tert-butyl-3-methylphenol) according to 3% of the solid content of the solution and add it to the resin solution. After ultrasonic treatment for 20 min, mechanical stirring is performed for 6 h. (2) Take 1.5 mL of the well mixed solution and pour it onto a glass plate with a PTFE film laid flat. Coat it with a comma scraper, and then place it under normal pressure at 70℃ for 10 h to dry. Then transfer it to a vacuum environment at 130℃ for heat treatment for 4 h. (3) After cooling, take out the heat-treated film, demold it, and put the film into a 0.5 M sulfuric acid solution at 70℃ for acid treatment for 1 h. Then put it into deionized water at the same temperature for 1 h. Take it out and dry it at 70℃ for 12 h to obtain a 20 μm thick membrane. Durable perfluorosulfonic acid proton exchange membrane 4 .
[0031] Comparative Example 1
[0032] (1) Take 5 mL of a 20 wt% perfluorosulfonic acid resin solution, without adding any additives, add 0.01 g of water, sonicate for 30 min, and then continue magnetic stirring for 8 h. (2) Take 1 mL of the solution and pour it onto a glass plate with a PTFE film laid flat for coating, then place it under normal pressure at 70 °C for 12 h to dry, and then transfer it to a vacuum environment at 140 °C for 3 h of heat treatment. (3) After cooling, take out the heat-treated film, demold it, and place the film in a 1 M sulfuric acid solution at 80 °C for acid treatment for 1.5 h, then place it in deionized water at the same temperature for 1.5 h, take it out and dry it at 80 °C for 12 h to obtain a 25 μm thick perfluorosulfonic acid proton exchange membrane without antioxidant.
[0033] Comparative Example 2
[0034] (1) Take 5 mL of a 20 wt% perfluorosulfonic acid resin solution, weigh 0.01 g of 3,4-dihydroxycinnamic acid according to 1% of the resin solid content in the solution, add it to the resin solution, sonicate for 30 min, and then continue to stir magnetically for 8 h. (2) Take 1 mL of the well-mixed solution and pour it onto a glass plate with a PTFE film laid flat for coating, then place it under normal pressure and dry at 70℃ for 12 h, and then heat treat it in a vacuum environment at 140℃ for 3 h. (3) After cooling, take out the heat-treated film, demold it, and put the film into a 1M sulfuric acid solution at 80℃ for acid treatment for 1.5 h, then put it into deionized water at the same temperature for 1.5 h, take it out and dry it at 80℃ for 12 h to obtain a 25 μm thick perfluorosulfonic acid proton exchange membrane with 1% 3,4-dihydroxycinnamic acid.
[0035] The perfluorosulfonic acid proton exchange membranes prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to performance testing, and the testing methods are as follows:
[0036] (1) Measurement of electrical conductivity.
[0037] The measurements were taken using an electrochemical impedance spectroscopy instrument at a temperature of 80°C and a humidity of 100% RH.
[0038] (2) Accelerated oxidation test.
[0039] The experiment was conducted using the Fenton oxidation method, and the specific steps are as follows:
[0040] Add 20 ppm of Fe to 100 mL of 30% hydrogen peroxide solution. 2+ For ion removal, the perfluorosulfonic acid proton exchange membrane was dried at 80°C for 2 hours, cooled, and then a quantitative amount of the perfluorosulfonic acid proton exchange membrane was quickly weighed and placed in Fenton solution. After being kept at 80°C for 12 hours, the sample was removed from the solution, washed with deionized water, dried at 80°C for 4 hours, and weighed. The weight loss was calculated.
[0041] (2) Durability test.
[0042] MEAs were prepared by bonding a perfluorosulfonic acid proton exchange membrane sample between the cathode and anode electrodes, with a Pt loading of 0.3 mg / cm³ at the cathode. 2 The Pt loading at the anode is 0.6 mg / cm³. 2 The MEA samples were assembled into a single piece with a diameter of 25 cm. 2 Fuel cell with effective area. Membrane durability was evaluated using an open-circuit voltage holding strategy under test conditions of 80°C and 90% RH, with hydrogen and air flow rates fixed at 50 mL / min and 100 mL / min, respectively.
[0043] Table 1. Conductivity, accelerated oxidation test, and durability test data of the membrane.
[0044] project Thickness (um) Electrical conductivity (S / cm) Quality loss (%) OCV(h) Example 1 35 0.2496 3.97 135 Example 2 25 0.2455 3.62 150 Example 3 10 0.2369 2.41 180 Example 4 20 0.2168 2.88 170 Comparative Example 1 25 0.2511 7.54 80 Comparative Example 2 25 0.2462 4.23 120
[0045] As shown in Table 1, the perfluorosulfonic acid proton exchange membranes with hindered phenolic antioxidants added in Examples 1-4 reduced the membrane degradation rate and effectively improved membrane durability compared with other antioxidants.
Claims
1. A durable perfluorosulfonic acid proton exchange membrane, characterized in that, The durable perfluorosulfonic acid proton exchange membrane comprises a hindered phenolic antioxidant and a perfluorosulfonic acid resin, with a thickness of 5-50 μm; wherein the hindered phenolic antioxidant is one or a mixture of two or more of the following: 3,5-di-tert-butyl-4-hydroxybenzoic acid, 4,4'-thiobis(6-tert-butyl-3-methylphenol), 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 2,6-di-tert-butyl-4-hydroxymethylphenol, α-tocopherol, 2-tert-butylhydroquinone, tert-butyl-4-hydroxyanisole, and 2,6-di-tert-butyl-p-cresol; The durable perfluorosulfonic acid proton exchange membrane is obtained by forming a membrane through solution blending of hindered phenolic antioxidant and perfluorosulfonic acid resin. Includes the following steps: (1) Mix the hindered phenolic antioxidant with the perfluorosulfonic acid resin solution evenly, form a film and then dry it; (2) The perfluorosulfonic acid composite proton exchange membrane containing hindered phenol antioxidant obtained in step (1) is placed in a vacuum drying oven for heat treatment. (3) The heat-treated composite proton exchange membrane containing hindered phenol antioxidant obtained in step (2) is immersed in sulfuric acid solution for acidification treatment, and then washed and dried with deionized water to obtain a clean and durable perfluorosulfonic acid proton exchange membrane. The solid content of the perfluorosulfonic acid resin solution is 1 to 30 wt%, the amount of hindered phenolic antioxidant added is 0.1 to 5 wt% of the mass of the perfluorosulfonic acid resin, and the viscosity of the perfluorosulfonic acid resin solution is 2.4 to 700 cps.
2. The method for preparing the durable perfluorosulfonic acid proton exchange membrane according to claim 1, characterized in that, The durable perfluorosulfonic acid proton exchange membrane is obtained by forming a membrane through solution blending of hindered phenolic antioxidant and perfluorosulfonic acid resin. Includes the following steps: (1) Mix the hindered phenolic antioxidant with the perfluorosulfonic acid resin solution evenly, form a film and then dry it; (2) The perfluorosulfonic acid composite proton exchange membrane containing hindered phenol antioxidant obtained in step (1) is placed in a vacuum drying oven for heat treatment. (3) The heat-treated composite proton exchange membrane containing hindered phenol antioxidant obtained in step (2) is immersed in sulfuric acid solution for acidification treatment, and then washed and dried with deionized water to obtain a clean and durable perfluorosulfonic acid proton exchange membrane. The solid content of the perfluorosulfonic acid resin solution is 1 to 30 wt%, the amount of hindered phenolic antioxidant added is 0.1 to 5 wt% of the mass of the perfluorosulfonic acid resin, and the viscosity of the perfluorosulfonic acid resin solution is 2.4 to 700 cps.
3. The method for preparing the durable perfluorosulfonic acid proton exchange membrane according to claim 2, characterized in that, In step (1), the mixing method of the durable perfluorosulfonic acid proton exchange membrane is one or a combination of two or more of the following: mechanical stirring, magnetic stirring, ultrasonic oscillation, high-speed shearing or cell disruption; the film formation method is spraying, scraping, casting, pouring, spin coating or impregnation.
4. The method for preparing the durable perfluorosulfonic acid proton exchange membrane according to claim 2, characterized in that, In step (1), the drying temperature is 60-80℃ and the drying time is 8-24h.
5. The method for preparing the durable perfluorosulfonic acid proton exchange membrane according to claim 2, characterized in that, In step (2), the heat treatment temperature is 120-160℃ and the heat treatment time is 2-6h.
6. The method for preparing the durable perfluorosulfonic acid proton exchange membrane according to claim 2, characterized in that, In step (3), the concentration of sulfuric acid solution is 0.1-1 mol / L, the treatment temperature is 60-90℃, and the treatment time is 1-3h; the temperature of deionized water treatment is 60-90℃, and the treatment time is 1-3h.
7. The method for preparing the durable perfluorosulfonic acid proton exchange membrane according to claim 2, characterized in that, In step (3), the drying temperature is 60-80℃ and the drying time is 8-24h.
8. The application of the durable perfluorosulfonic acid proton exchange membrane according to claim 1 or the durable perfluorosulfonic acid proton exchange membrane prepared by any one of the preparation methods according to claims 2-7, characterized in that, The durable perfluorosulfonic acid proton exchange membrane is used in fuel cells and water electrolysis for hydrogen production.