High-stability self-humidifying proton exchange membrane as well as preparation method and application thereof

Abstract

The invention relates to the technical field of batteries, and provides a high-stability self-humidifying proton exchange membrane as well as a preparation method and application thereof. The high-stability self-humidifying proton exchange membrane is prepared from the following raw material components in parts by weight: 10 parts of sulfonated polyetheretherketone, 100 parts of perfluorinated sulfonic acid resin and 5 to 20 parts of ZrP / CeO2 composite material, the ZrP / CeO2 composite material comprises the following raw materials: zirconium phosphate and cerium oxide in a weight ratio of 1: (1-2). According to the technical scheme, the problems of relatively poor stability and relatively low proton conductivity of the proton exchange membrane in related technologies are solved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a highly stable self-humidifying proton exchange membrane, its preparation method, and its application. Background Technology

[0002] As a core component of hydrogen-oxygen fuel cells, the proton exchange membrane not only plays a dual role in conducting protons and separating the reacting gases at the anode and cathode, but also directly affects the output performance, service life, and cost control of the fuel cell.

[0003] Currently, commercially available proton exchange membranes mainly use perfluorosulfonic acid (PFSA) polymers, which exhibit good proton conduction properties under humid conditions. However, PFSA membranes are expensive to manufacture and not resistant to low humidity; their performance deteriorates significantly at relatively low humidity levels.

[0004] To overcome these defects of perfluorosulfonic acid membranes, technicians have tried various solutions. Among them, sulfonated polyether ether ketone (SPEEK) has attracted widespread attention due to its lower cost, readily available raw materials, relatively good resistance to low humidity, and good film-forming properties. Sulfonated polyether ether ketone obtains proton conduction ability by introducing sulfonic acid groups on its aromatic ring. However, pure sulfonated polyether ether ketone membranes are prone to excessive swelling, and their antioxidant stability is significantly lower than that of perfluorosulfonic acid membranes. These problems limit the large-scale application of pure sulfonated polyether ether ketone membranes in fuel cells.

[0005] In light of the respective advantages and disadvantages of perfluorosulfonic acid membranes and sulfonated polyether ether ketone membranes, researchers have recently begun exploring composite membrane solutions that combine the two. Typically, solution blending or physical blending methods are used to combine the two to obtain composite membranes. However, these simple physical blending methods often face problems such as phase separation, poor interfacial compatibility, and performance instability, which limits the improvement of the final proton exchange membrane's stability and proton conductivity.

[0006] Therefore, developing a proton exchange membrane that has both good stability and good proton conductivity is of great significance for meeting the application requirements of proton exchange membranes in fields such as fuel cells. Summary of the Invention

[0007] This invention proposes a highly stable self-humidifying proton exchange membrane, its preparation method, and its application, which solves the problems of poor stability and low proton conductivity of proton exchange membranes in related technologies.

[0008] The technical solution of the present invention is as follows: This invention proposes a highly stable self-humidifying proton exchange membrane, the raw materials of which include the following components in parts by weight: 10 parts of sulfonated polyether ether ketone, 100 parts of perfluorosulfonic acid resin, and 5-20 parts of ZrP / CeO2 composite material; The raw materials for the ZrP / CeO2 composite material include zirconium phosphate and cerium oxide in a weight ratio of 1:1 to 2.

[0009] As a further technical solution, the weight ratio of zirconium phosphate to cerium oxide is 1:1.5.

[0010] As a further technical solution, the preparation method of the ZrP / CeO2 composite material includes the following steps: The zirconium phosphate, cerium oxide and water are mixed evenly and ball-milled to obtain a ZrP / CeO2 ball milling slurry. The ZrP / CeO2 ball milling slurry is then spray-dried to obtain the ZrP / CeO2 composite material.

[0011] As a further technical solution, the weight ratio of zirconium phosphate to water is 1:150~250, for example, it can be 1:150, 1:180, 1:200, 1:210, 1:230, 1:250, preferably 1:150, 1:200, 1:250, and more preferably 1:200.

[0012] As a further technical solution, during ball milling, the rotation speed is 50~150 r / min, for example, 50 r / min, 100 r / min, or 150 r / min, preferably 100 r / min; the revolution speed is 500~800 r / min, for example, 500 r / min, 600 r / min, 700 r / min, or 800 r / min, preferably 600 r / min; the temperature is 25~35℃, for example, 25℃, 30℃, or 35℃, preferably 30℃; and the time is 4~6h, for example, 4h, 5h, or 6h, preferably 5h.

[0013] As a further technical solution, during the spray drying process, the inlet temperature is 160~200℃, for example, 160℃, 170℃, 180℃, 190℃, 200℃, preferably 180℃; the outlet temperature is 80~100℃, for example, 80℃, 90℃, 100℃, preferably 90℃; the feed rate is 3~8mL / min, for example, 3mL / min, 4mL / min, 5mL / min, 6mL / min, 7mL / min, 8mL / min, preferably 5mL / min; and the atomizer speed is 20000~30000r / min, for example, 20000r / min, 25000r / min, 30000r / min, preferably 25000r / min.

[0014] As a further technical solution, the raw materials also include 1 to 5 parts of sulfonated graphene, for example, 1 part, 2 parts, 3 parts, 4 parts, or 5 parts.

[0015] In this invention, when the raw materials also include sulfonated graphene, the specific surface area of ​​sulfonated graphene is relatively high. At the same time, the sulfonic acid groups on its surface can enhance its interaction with other components in the proton exchange membrane, further stabilizing the proton exchange membrane. In addition, the addition of sulfonated graphene can provide more protons to the composite membrane, further improving the proton conductivity of the proton exchange membrane.

[0016] As a further technical solution, the raw material also includes ionic liquid; The ionic liquid includes 1-ethyl-3-methylimidazolium trifluoromethanesulfonate; The amount of the ionic liquid added is 1 to 3 parts, for example, 1 part, 2 parts, or 3 parts.

[0017] In this invention, when the raw materials also include ionic liquids, the introduction of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquids, with their strong polarity and hygroscopicity, allows for the active adsorption of water molecules. Simultaneously, it can form strong ion-dipole and hydrogen bonding interactions with water, "anchoring" these water molecules within the polymer network, thereby significantly enhancing the membrane's water absorption and retention capacity under high-temperature or dry environments.

[0018] This invention proposes a method for preparing a highly stable self-humidifying proton exchange membrane, which includes the following steps: S1. After the sulfonated polyether ether ketone and the first solvent are mixed evenly, electrospinning is performed to obtain a nanofiber reinforced skeleton. S2. Mix the perfluorosulfonic acid resin and the second solvent evenly, add the remaining components, and stir evenly to obtain the casting solution. S3. The casting solution is coated onto the nanofiber-reinforced skeleton, dried, and hot-pressed to obtain the highly stable self-humidifying proton exchange membrane.

[0019] In this invention, sulfonated polyether ether ketone is first electrospun to obtain a reinforcing skeleton. Then, a casting solution containing perfluorosulfonic acid resin is coated onto the reinforcing skeleton. The perfluorosulfonic acid resin and other components in the proton exchange membrane can effectively fill and adhere to the reinforcing skeleton, forming an interpenetrating structure containing sulfonated polyether ether ketone and perfluorosulfonic acid resin. Compared with traditional physical blending or simple lamination, this can effectively improve the interfacial compatibility between sulfonated polyether ether ketone and perfluorosulfonic acid resin, and improve the structural stability of the proton exchange membrane.

[0020] As a further technical solution, in step S1, when the mixture is uniform, magnetic stirring is used, the stirring speed is 150~250r / min, for example, 150r / min, 200r / min, 250r / min, preferably 200r / min, the time is 4~6h, for example, 4h, 5h, 6h, preferably 5h, and the temperature is 25~35℃, for example, 25℃, 30℃, 35℃, preferably 30℃.

[0021] As a further technical solution, the weight ratio of the sulfonated polyether ether ketone to the first solvent is 1:8 to 10, for example, it can be 1:8, 1:9, or 1:10, preferably 1:9.

[0022] As a further technical solution, the weight ratio of the perfluorosulfonic acid resin to the second solvent is 1:18~20, for example, it can be 1:18, 1:19, or 1:20, preferably 1:19.

[0023] As a further technical solution, in step S2, when the mixture is uniform, magnetic stirring is used, the stirring speed is 150~250r / min, for example, 150r / min, 200r / min, 250r / min, preferably 200r / min, the temperature is 60~90℃, for example, 60℃, 70℃, 80℃, 90℃, preferably 80℃, and the time is 4~6h, for example, 4h, 5h, 6h, preferably 5h.

[0024] As a further technical solution, during the coating process, the thickness of the wet film formed by the casting liquid is 100~200μm, for example, it can be 100μm, 150μm, or 200μm, preferably 150μm.

[0025] As a further technical solution, in step S3, the drying temperature is 70~90℃, for example, 70℃, 80℃, 90℃, preferably 80℃, and the time is 6~10h, for example, 6h, 7h, 8h, 9h, 10h, preferably 8h; During the hot pressing process, the pressure is 800~1200 kg, for example, 800 kg, 900 kg, 1000 kg, 1100 kg, 1200 kg, preferably 1000 kg; the time is 1~3 min, for example, 1 min, 2 min, 3 min, preferably 2 min; and the temperature is 60~100℃, for example, 60℃, 70℃, 80℃, 90℃, 100℃, preferably 80℃.

[0026] As a further technical solution, the first solvent and the second solvent each independently include one or more of N-methylpyrrolidone, dimethyl sulfoxide and N,N-dimethylformamide, preferably N-methylpyrrolidone.

[0027] As a further technical solution, during electrospinning, the voltage is 14~16kV, for example, 14kV, 15kV, 16kV, preferably 15kV; the distance between the needle and the receiver is 14~20cm, for example, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm, 20cm, preferably 15cm; the spinning advance speed is 0.05~0.15mL / h, for example, 0.05mL / h, 0.1mL / h, 0.15mL / h, preferably 0.1mL / h; and the spinning temperature is 40~60℃, for example, 40℃, 45℃, 50℃, 55℃, 60℃, preferably 50℃.

[0028] The present invention also proposes the application of a highly stable self-humidifying proton exchange membrane or a highly stable self-humidifying proton exchange membrane prepared by the aforementioned preparation method in fuel cells.

[0029] The working principle and beneficial effects of this invention are as follows: In this invention, a high-stability self-humidifying proton exchange membrane uses sulfonated polyether ether ketone (PEEK) as a reinforcing framework. The presence of sulfonic acid groups on PEEK effectively improves its proton conductivity. Simultaneously, perfluorosulfonic acid resin and a ZrP / CeO2 composite material are introduced into the PEEK reinforcing framework. The perfluorosulfonic acid resin can interact with the sulfonic acid groups in PEEK, constructing a more efficient proton conduction channel while improving the proton conductivity of the proton exchange membrane. The ZrP / CeO2 composite material contains zirconium phosphate and cerium oxide as raw materials. With its layered structure and good stability, cerium oxide can improve the hydrolytic stability of proton exchange membranes to a certain extent. Cerium oxide also has certain catalytic and oxygen storage capabilities, which can inhibit further damage to the proton exchange membrane by free radicals generated by hydrolysis. By adding the ZrP / CeO2 composite material obtained by combining zirconium phosphate and cerium oxide, and using it in combination with perfluorosulfonic acid resin and sulfonated polyether ether ketone, the proton conductivity of the proton exchange membrane can be improved, while the swelling rate of the proton exchange membrane can be reduced, thus improving the hydrolytic stability of the proton exchange membrane. This can effectively meet its application requirements in fuel cells. Attached Figure Description

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0031] Figure 1 This is a SEM image of the nanofiber-reinforced skeleton in Example 11 of the present invention; Figure 2 The results of in-situ durability tests are shown for the proton exchange membrane prepared in Example 11 of this invention after it was assembled into a fuel cell. Figure 3 The results show the proton conductivity of the proton exchange membranes prepared in Examples 3, 8, 11 and Comparative Example 1 of this invention at 80°C and under different humidity conditions. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] In the following examples and comparative examples, sulfonated polyether ether ketone, with an active ingredient content of 98.5%, was purchased from Jinan Maina Technology Co., Ltd. Perfluorosulfonic acid resin, with an active ingredient content of 98%, was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd. Sulfonated graphene with an average particle size of 100 nm was purchased from Fuzhou Aoxi New Materials Co., Ltd. Zirconium phosphate, α-type, with an active ingredient content of 99%, was purchased from Mianzhu Yaolong Chemical Co., Ltd. Cerium oxide, with an average particle size of 50 nm and an effective ingredient content of 99%, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. 1-Ethyl-3-methylimidazolium trifluoromethanesulfonate, with an active ingredient content of 98%, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Sodium phosphate, also known as trisodium phosphate, has an active ingredient content of 98%, produced by Zhengzhou Aikem Chemical Co., Ltd. Sulfonated polyethersulfone with a sulfonation degree of 30% was purchased from Dechi Technology (Linyi) Co., Ltd.

[0034] Example 1 A method for preparing a highly stable self-humidifying proton exchange membrane includes the following steps: S0. Add 1g of zirconium phosphate, 1.5g of cerium oxide, and 200g of water to a ball mill jar. Ball mill for 5 hours at a rotation speed of 100r / min, a revolution speed of 600r / min, and a temperature of 30℃ to obtain ZrP / CeO2 ball milling slurry. Then, spray dry the slurry at an inlet temperature of 180℃, an outlet temperature of 90℃, a feed rate of 5mL / min, and an atomizer speed of 25000r / min to obtain ZrP / CeO2 composite material. S1. 0.1 g of sulfonated polyether ether ketone and 0.9 g of N-methylpyrrolidone were stirred at 30 °C and 200 r / min under magnetic stirring for 5 h. Then, electrospinning was carried out under the conditions of 15 kV voltage, 15 cm distance between needle and receiver, 0.1 mL / h spinning speed and 50 °C during spinning to obtain nanofiber reinforced skeleton. S2. After stirring 1g of perfluorosulfonic acid resin and 19g of N-methylpyrrolidone at 80℃ and 200r / min under magnetic stirring for 5h, add 0.05g of ZrP / CeO2 composite material and stir evenly to obtain casting solution. S3. Using a 150µm doctor blade, the above casting solution is coated onto the nanofiber reinforced skeleton on one side. After drying at 80℃ for 8 hours, it is hot-pressed at 80℃ and 1000kg pressure for 2 minutes to obtain a highly stable self-humidifying proton exchange membrane with a thickness of 150µm.

[0035] Example 2 The only difference between this embodiment and Embodiment 1 is that in this embodiment, the amount of ZrP / CeO2 composite material added is 0.1g.

[0036] Example 3 The only difference between this embodiment and Embodiment 1 is that in this embodiment, the amount of ZrP / CeO2 composite material added is 0.15g.

[0037] Example 4 The only difference between this embodiment and Embodiment 1 is that in this embodiment, the amount of ZrP / CeO2 composite material added is 0.2g.

[0038] Example 5 The only difference between this embodiment and Embodiment 3 is that step S2 in the preparation method of the high-stability self-humidifying proton exchange membrane in this embodiment is different, specifically: 1g of perfluorosulfonic acid resin and 19g of N-methylpyrrolidone were stirred at 80℃ and 200r / min for 5h with magnetic stirring. Then, 0.15g of ZrP / CeO2 composite material and 0.01g of sulfonated graphene were added and stirred evenly to obtain the casting solution.

[0039] Example 6 The only difference between this embodiment and Embodiment 5 is that in this embodiment, 0.02g of sulfonated graphene is added.

[0040] Example 7 The only difference between this embodiment and Embodiment 5 is that in this embodiment, 0.03g of sulfonated graphene is added.

[0041] Example 8 The only difference between this embodiment and Embodiment 5 is that in this embodiment, 0.04g of sulfonated graphene is added.

[0042] Example 9 The only difference between this embodiment and Embodiment 5 is that in this embodiment, 0.05g of sulfonated graphene is added.

[0043] Example 10 The only difference between this embodiment and Embodiment 8 is that step S2 in the preparation method of the high-stability self-humidifying proton exchange membrane in this embodiment is different, specifically: After stirring 1g of perfluorosulfonic acid resin and 19g of N-methylpyrrolidone at 80℃ and 200r / min for 5h with magnetic stirring, 0.15g of ZrP / CeO2 composite material, 0.04g of sulfonated graphene and 0.01g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate were added and stirred evenly to obtain the casting solution.

[0044] Example 11 The only difference between this embodiment and Example 10 is that in this embodiment, 0.02g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate is added; The SEM image of the nanofiber-reinforced skeleton obtained in Example 11 is shown below. Figure 1 As shown.

[0045] Example 12 The only difference between this embodiment and Example 10 is that in this embodiment, 0.03g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate is added.

[0046] Example 13 The only difference between this embodiment and Embodiment 1 is that step S0 in the preparation method of the high-stability self-humidifying proton exchange membrane in this embodiment is different, specifically: S0. Add 1g of zirconium phosphate, 1g of cerium oxide, and 200g of water to a ball mill jar. Ball mill for 5 hours at a rotation speed of 100r / min, a revolution speed of 600r / min, and a temperature of 30℃ to obtain ZrP / CeO2 ball milling slurry. Then, spray dry the slurry at an inlet temperature of 180℃, an outlet temperature of 90℃, a feed rate of 5mL / min, and an atomizer speed of 25000r / min to obtain ZrP / CeO2 composite material.

[0047] Example 14 The only difference between this embodiment and Embodiment 1 is that step S0 in the preparation method of the high-stability self-humidifying proton exchange membrane in this embodiment is different, specifically: S0. Add 1g zirconium phosphate, 2g cerium oxide, and 200g water to a ball mill jar and ball mill for 5 hours at a rotation speed of 100r / min, a revolution speed of 600r / min, and a temperature of 30℃ to obtain ZrP / CeO2 ball milling slurry. Then, spray dry the slurry at an inlet temperature of 180℃, an outlet temperature of 90℃, a feed rate of 5mL / min, and an atomizer speed of 25000r / min to obtain ZrP / CeO2 composite material.

[0048] Example 15 The only difference between this embodiment and Embodiment 11 is that the preparation method of the wet proton exchange membrane is different in this embodiment, specifically: 0.1g of sulfonated polyether ether ketone, 1g of perfluorosulfonic acid resin, 0.15g of ZrP / CeO2 composite material, 0.04g of sulfonated graphene, and 0.01g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate were added to 19g of N-methylpyrrolidone, stirred evenly, poured onto a glass plate, and dried at 80℃ for 8h to form a film.

[0049] Example 16 The only difference between this embodiment and Embodiment 11 is that the preparation method of the wet proton exchange membrane is different in this embodiment, specifically: S0. Add 1g of zirconium phosphate, 1.5g of cerium oxide, and 200g of water to a ball mill jar. Ball mill for 5 hours at a rotation speed of 100r / min, a revolution speed of 600r / min, and a temperature of 30℃ to obtain ZrP / CeO2 ball milling slurry. Then, spray dry the slurry at an inlet temperature of 180℃, an outlet temperature of 90℃, a feed rate of 5mL / min, and an atomizer speed of 25000r / min to obtain ZrP / CeO2 composite material. S1. 0.1g of sulfonated polyether ether ketone and 0.9g of N-methylpyrrolidone were stirred at 30℃ and 200r / min for 5h to obtain a solution. The solution was cast onto a glass plate and dried at 80℃ for 8h to obtain a sulfonated polyether ether ketone film. S2. After stirring 1g of perfluorosulfonic acid resin and 19g of N-methylpyrrolidone at 80℃ and 200r / min under magnetic stirring for 5h, add 0.15g of ZrP / CeO2 composite material, 0.04g of sulfonated graphene and 0.01g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, and stir evenly to obtain casting solution; S3. Using a 150µm doctor blade, the above casting solution is coated onto the sulfonated polyether ether ketone membrane on one side. After drying at 80°C for 8 hours, it is hot-pressed at 80°C and 1000kg pressure for 2 minutes to obtain the composite proton exchange membrane.

[0050] Comparative Example 1 The only difference between this comparative example and Example 1 is that the preparation method of the highly stable self-humidifying proton exchange membrane is different in this comparative example, specifically: S1. 0.1 g of sulfonated polyether ether ketone and 0.9 g of N-methylpyrrolidone were stirred at 30 °C and 200 r / min under magnetic stirring for 5 h. Then, electrospinning was carried out under the conditions of 15 kV voltage, 15 cm distance between needle and receiver, 0.1 mL / h spinning speed and 50 °C during spinning to obtain nanofiber reinforced skeleton. S2. After stirring 1g of perfluorosulfonic acid resin and 19g of N-methylpyrrolidone at 80℃ and 200r / min under magnetic stirring for 5h, a casting solution is obtained. S3. Using a 150µm doctor blade, the above casting solution is coated onto the nanofiber reinforced skeleton on one side. After drying at 80℃ for 8 hours, it is hot-pressed at 80℃ and 1000kg pressure for 2 minutes to obtain a highly stable self-humidifying proton exchange membrane with a thickness of 150µm.

[0051] Comparative Example 2 The only difference between this comparative example and Example 1 is that, in this comparative example, the perfluorosulfonic acid resin is replaced with an equal amount of sulfonated polyethersulfone.

[0052] Comparative Example 3 The only difference between this comparative example and Example 1 is that, in this comparative example, the ZrP / CeO2 composite material is replaced with an equal amount of NaP / CeO2 composite material. The preparation method of NaP / CeO2 composite material is as follows: 1g of sodium phosphate, 1.5g of cerium oxide and 200g of water are added to a ball mill jar and ball milled for 5h at a rotation speed of 100r / min, a revolution speed of 600r / min and a temperature of 30℃ to obtain NaP / CeO2 ball milling slurry. Then, spray drying is carried out at an inlet temperature of 180℃, an outlet temperature of 90℃, a feed rate of 5mL / min and an atomizer speed of 25000r / min to obtain NaP / CeO2 composite material.

[0053] Comparative Example 4 The only difference between this comparative example and Example 1 is that, in this comparative example, the ZrP / CeO2 composite material is replaced with an equal amount of ZrP / SiO2 composite material. The ZrP / SiO2 composite material is prepared as follows: 1g of zirconium phosphate, 1.5g of silica, and 200g of water are added to a ball mill jar and ball-milled for 5 hours at a rotation speed of 100r / min, a revolution speed of 600r / min, and a temperature of 30℃ to obtain ZrP / SiO2 ball milling slurry. Then, it is spray-dried at an inlet temperature of 180℃, an outlet temperature of 90℃, a feed rate of 5mL / min, and an atomizer speed of 25000r / min to obtain the ZrP / SiO2 composite material.

[0054] Comparative Example 5 The only difference between this comparative example and Example 1 is that, in this comparative example, sulfonated polyether ether ketone is replaced with an equal amount of polyether ether ketone.

[0055] Experimental Example The high-stability self-humidifying proton exchange membranes prepared in Examples 1-16 and Comparative Examples 1-5 were subjected to the following performance tests: (1) Proton conductivity test: An electrochemical workstation was used for the test, employing the AC impedance method. Before the test, to ensure the proton exchange membrane sample was in the same temperature and humidity environment as the test environment, the sample was placed in a constant temperature and humidity chamber for 8 hours. The temperature for testing proton conductivity at different humidity levels was 80℃, and the humidity was 100%. During the test, the proton exchange membrane sample was clamped between test fixtures. The core structure of the test fixtures consisted of two parallel and opposite metal electrodes, with the vertical distance between the two metal electrodes measured as L. The test frequency range was 1Hz to 100kHz. The conductivity σ calculation formula is as follows: In the formula: σ is the proton conductivity (mS·cm) -1 L is the distance between the two electrodes (cm), R is the intrinsic impedance (Ω); d is the thickness of the proton exchange membrane sample (cm); w is the width of the proton exchange membrane sample (cm). (2) Water absorption rate test: The proton exchange membrane sample was dried in an oven at 80℃ for 24h, and the mass of the proton exchange membrane sample was measured as m0 (g). Then, the proton exchange membrane sample was soaked in distilled water at 80℃ for 8h. The water on the surface of the proton exchange membrane sample was removed with filter paper, and the mass of the proton exchange membrane sample was measured as m1 (g) within 30s. The water absorption rate Δm = (m1-m0) / m0 × 100%; (3) Swelling rate test: The swelling rate test shall be conducted in accordance with the method in GB / T 20042.3-2022 "Proton exchange membrane fuel cells Part 3: Proton exchange membrane test method"; (4) Hydrolysis stability test: The dry proton exchange membrane sample with a mass of Wo (g) was soaked in deionized water at 80℃ for 48h, and then dried at 80℃ for 8h. Its mass was measured as Wt (g). The mass loss rate of the proton exchange membrane sample was tested according to the following formula: Wc=(Wo-Wt) / Wo×100%, where the mass loss rate characterizes the hydrolysis stability. (5) Ion exchange capacity test: The acid-base titration method is used for testing. Weigh the proton exchange membrane sample and soak it in a 1 mol / L sodium chloride aqueous solution for 24 h. Then add phenolphthalein reagent and titrate with a 0.005 mol / L sodium hydroxide aqueous solution until the solution is neutral. Record the volume of sodium hydroxide aqueous solution consumed. The IEC formula for calculating ion exchange capacity is as follows: In the formula: V NaOH The volume (mL) of sodium hydroxide aqueous solution consumed; C NaOH denoted as , where is the concentration of NaOH in the sodium hydroxide aqueous solution (mol / L); m is the mass of the proton exchange membrane sample (g). (6) Mechanical property testing: The proton exchange membrane sample was made into a rectangular strip. A thin film tensile testing machine was used, with the tensile speed set to 5 mm / min and the initial gauge length to 20 mm. The tensile test was performed using the formula... The tensile strength is calculated, where: σ1 is the tensile strength (MPa), P is the maximum load (N), b is the width of the rectangular strip (mm), and d is the thickness of the rectangular strip (mm). The thickness is measured by a thickness gauge. The test results are shown in Table 1.

[0056] Table 1 Performance test results of Examples 1-14 and Comparative Examples 1-5

[0057] As shown in Table 1, compared with Comparative Examples 1-4, the high-stability self-humidifying proton exchange membranes prepared in Examples 1-4 and 13-14 exhibited improved proton conductivity, decreased swelling ratio, and improved hydrolytic stability. This indicates that the combined use of sulfonated polyether ether ketone and perfluorosulfonic acid resin in the proton exchange membrane, along with the introduction of ZrP / CeO2 composite material, can effectively improve the overall performance of the proton exchange membrane, increasing its proton conductivity to 146.66 mS·cm. -1 The swelling rate was reduced to below 7.06%, and after the proton exchange membrane sample was immersed in deionized water at 80℃ for 48 hours, the mass loss rate was reduced to below 4.49%, which shows good hydrolytic stability and can meet its application in fuel cells.

[0058] Compared with Comparative Example 5, the proton conductivity of the high-stability self-humidifying proton exchange membranes prepared in Examples 1-4 was significantly improved, indicating that using sulfonated polyether ether ketone as the skeleton material in the proton exchange membrane can effectively improve the proton conductivity of the proton exchange membrane.

[0059] Furthermore, compared to Examples 1-9, the high-stability self-humidifying proton exchange membranes prepared in Examples 10-12 exhibited further improved proton conductivity, further reduced swelling ratio, and further improved hydrolytic stability. This indicates that the proton exchange membrane, using sulfonated polyether ether ketone as the backbone material and adding perfluorosulfonic acid resin, along with the introduction of ZrP / CeO2 composite material, sulfonated graphene, and ionic liquid, can further enhance the proton conductivity and hydrolytic stability of the proton exchange membrane through the rational combination of these components, achieving a proton conductivity of up to 181.33 mS·cm. -1 The swelling rate was reduced to below 6.47%.

[0060] Compared with Example 11, the proton conductivity and hydrolytic stability of the high-stability self-humidifying proton exchange membranes prepared in Examples 15-16 were reduced. This indicates that the proton exchange membrane obtained by first electrospinning sulfonated polyether ether ketone (PEEK) as a skeleton material, and then coating a casting solution containing perfluorosulfonic acid resin, ZrP / CeO2 composite material, sulfonated graphene, and ionic liquid onto the PEEK skeleton material, has better stability and overall performance than the proton exchange membrane obtained by directly blending PEEK, perfluorosulfonic acid resin, ZrP / CeO2 composite material, sulfonated graphene, and ionic liquid, or by directly coating a casting solution containing perfluorosulfonic acid resin, ZrP / CeO2 composite material, sulfonated graphene, and ionic liquid onto sulfonated PEK that has not undergone electrospinning.

[0061] Figure 1 The image shows a SEM image of the nanofiber-reinforced skeleton of Example 11. As can be seen from the image, the nanofibers are loosely arranged, which allows the casting solution containing perfluorosulfonic acid resin to better fill the gaps as a nanofiber-reinforced skeleton.

[0062] Figure 2 The in-situ durability test results of the high-stability self-humidifying proton exchange membrane prepared in Example 11 after it was assembled into a fuel cell were used to test the membrane. During operation, the fuel cell generates free radicals, which can oxidize and erode the proton exchange membrane, leading to a drop in open-circuit voltage or even failure of the proton exchange membrane. After 100 hours of durability testing, the open-circuit voltage of the proton exchange membrane obtained in Example 11 remained at 0.895V, indicating that the proton exchange membrane prepared by the present invention has excellent durability and stability.

[0063] Figure 3The results show the proton conductivity of the proton exchange membranes prepared in Examples 3, 8, 11 and Comparative Example 1 under different humidity conditions at 80°C. After adding ZrP / CeO2 composite material and sulfonated graphene, the proton conductivity of Examples 3 and 8 was improved compared to Comparative Example 1 under low humidity (≤75%), but the improvement was small. However, after adding the ionic liquid of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, the proton conductivity of the proton exchange membrane prepared in Example 11 was significantly improved under humidity ≤75%, proving that the self-humidification and water retention performance of the proton exchange membrane were significantly improved after adding 1-ethyl-3-methylimidazolium trifluoromethanesulfonate.

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly stable self-humidifying proton exchange membrane, characterized in that, The raw materials consist of the following components in parts by weight: 10 parts of sulfonated polyether ether ketone, 100 parts of perfluorosulfonic acid resin, and 5-20 parts of ZrP / CeO2 composite material; The raw materials for the ZrP / CeO2 composite material include zirconium phosphate and cerium oxide in a weight ratio of 1:1 to 2.

2. The highly stable self-humidifying proton exchange membrane according to claim 1, characterized in that, The weight ratio of zirconium phosphate to cerium oxide is 1:1.

5.

3. The highly stable self-humidifying proton exchange membrane according to claim 1, characterized in that, The preparation method of the ZrP / CeO2 composite material includes the following steps: The zirconium phosphate, cerium oxide and water are mixed evenly and ball-milled to obtain a ZrP / CeO2 ball milling slurry. The ZrP / CeO2 ball milling slurry is then spray-dried to obtain the ZrP / CeO2 composite material.

4. The highly stable self-humidifying proton exchange membrane according to claim 3, characterized in that, During the spray drying process, the inlet temperature is 160~200℃, the outlet temperature is 80~100℃, the feed rate is 3~8mL / min, and the atomizer speed is 20000~30000r / min.

5. The highly stable self-humidifying proton exchange membrane according to claim 1, characterized in that, The raw materials also include 1 to 5 parts of sulfonated graphene.

6. The highly stable self-humidifying proton exchange membrane according to claim 1, characterized in that, The raw materials also include ionic liquids; The ionic liquid includes 1-ethyl-3-methylimidazolium trifluoromethanesulfonate; The amount of the ionic liquid added is 1 to 3 parts.

7. A method for preparing a highly stable self-humidifying proton exchange membrane, used to prepare the highly stable self-humidifying proton exchange membrane according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. After the sulfonated polyether ether ketone and the first solvent are mixed evenly, electrospinning is performed to obtain a nanofiber reinforced skeleton. S2. Mix the perfluorosulfonic acid resin and the second solvent evenly, add the remaining components, and stir evenly to obtain the casting solution. S3. The casting solution is coated onto the nanofiber-reinforced skeleton, dried, and hot-pressed to obtain the highly stable self-humidifying proton exchange membrane.

8. The method for preparing a highly stable self-humidifying proton exchange membrane according to claim 7, characterized in that, The first solvent and the second solvent each independently comprise one or more of N-methylpyrrolidone, dimethyl sulfoxide, and N,N-dimethylformamide.

9. The method for preparing a highly stable self-humidifying proton exchange membrane according to claim 7, characterized in that, During electrospinning, the voltage is 14~16kV, the distance between the needle and the receiver is 14~20cm, the spinning speed is 0.05~0.15mL / h, and the spinning temperature is 40~60℃.

10. The application of a highly stable self-humidifying proton exchange membrane according to any one of claims 1 to 6, or a highly stable self-humidifying proton exchange membrane prepared by the preparation method according to any one of claims 7 to 9, in fuel cells.

Images