A sulfonated polyaryletherketone sulfone / protonated polyheptamethine imide composite proton exchange membrane and its preparation method

Abstract

This invention discloses a sulfonated polyaryletherketone sulfone / protonated polyheptamethrinimide composite proton exchange membrane and its preparation method, belonging to the fields of polymer materials and fuel cell technology. The method includes: synthesizing protonated polyheptamethrinimide (H-PHI); preparing a sulfonated polyaryletherketone sulfone (SPAEKS) solution; dispersing H-PHI in the SPAEKS solution to form a casting solution, with a mass ratio of SPAEKS to H-PHI of 1:0.005–0.02; and forming a membrane by casting. This invention also discloses the composite membrane prepared by this method, with a thickness of 20–25 μm and an in-plane proton conductivity of not less than 0.1801 S cm under conditions of 80℃ and 100% relative humidity. ‑1 The tensile strength is ≥35 MPa. This invention, by introducing two-dimensional porous H-PHI, constructs a continuous hydrogen bond network and a rigid framework in a SPAEKS matrix, achieving both high proton conductivity and good mechanical properties, and has broad application prospects in the field of fuel cells.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials and fuel cells, specifically relating to a sulfonated polyaryletherketone sulfone / protonated polyheptamethine imide composite proton exchange membrane and its preparation method. Background Technology

[0002] Highly efficient and clean new energy technologies are a crucial development direction in the current energy sector. Fuel cells, as power generation devices that directly convert chemical energy into electrical energy, have attracted widespread attention due to their significantly higher energy conversion efficiency compared to traditional internal combustion engines. Among them, proton exchange membrane fuel cells (PEMFCs) are an important type of fuel cell, characterized by high efficiency, low emissions, stable operation, rapid start-up, and low noise. PEMFCs can be applied in transportation, stationary power generation, and portable power sources.

[0003] As a key component of PEMFCs, the performance parameters of the proton exchange membrane (PEM) significantly influence the fuel cell's lifespan and operating efficiency. Currently, the most widely used commercially available membrane is the perfluorosulfonic acid membrane, also known as the Nafion membrane. It is primarily composed of hydrophilic groups (-SO3H) and a hydrophobic polytetrafluoroethylene (PTFE) framework, forming a well-separated phase structure and exhibiting high proton conductivity. However, its synthesis process is complex and costly, and its proton conductivity drops sharply at high temperatures. These shortcomings have made the development of PEM materials that combine high proton conductivity, excellent mechanical properties, and low cost a key research focus in this field.

[0004] Sulfonated poly(arylene etherketone sulfone) (SPAEKS), a fluorine-free aromatic proton exchange membrane, is an important candidate for proton exchange membrane matrix materials due to its excellent electrochemical performance, high proton conductivity, and low cost. However, the proton conductivity of SPAEKS is closely related to its degree of sulfonation (DS). While increasing the degree of sulfonation helps improve proton conductivity, it easily leads to excessive swelling of the membrane material, resulting in a significant deterioration of mechanical properties. Therefore, how to achieve synergistic optimization of proton conductivity and mechanical properties at the molecular and microstructural levels has become an urgent technical challenge to be solved in this field.

[0005] Poly(Heptazine Imide) (PHI) is a two-dimensional porous carbon-nitrogen nanomaterial with an abundant nitrogen heterocyclic structure, a highly conjugated π-electron system, and a rich layered network in its molecular structure. This structure endows PHI with unique physicochemical properties, including high stability, high crystallinity, and potential proton conductivity. Protonated poly(Heptazine Imide) (H-PHI), obtained through acidification, contains abundant nitrogen-containing groups (-NH). x H-PHI not only provides proton hopping sites but also effectively complements and participates in hydrogen bond-mediated proton transfer processes within the water network. Based on these properties, introducing H-PHI into polymer matrices offers a potential solution to the challenge of balancing high proton conductivity with good mechanical properties. Summary of the Invention

[0006] The purpose of this invention is to solve the problem of the difficulty in achieving both proton conductivity and mechanical properties in sulfonated polyarylether ketone sulfone proton exchange membranes, and to provide a sulfonated polyarylether ketone sulfone / protonated polyheptamethine imide composite proton exchange membrane and its preparation method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a sulfonated polyarylether ketone sulfone / protonated polyheptamethine imide composite proton exchange membrane includes the following steps: Step 1: Synthesize protonated polyheptamethrin imide (H-PHI); Step 2: Prepare a sulfonated polyaryletherketone sulfone (SPAEKS) solution; Step 3: Add H-PHI to the SPAEKS solution obtained in Step 2 to obtain the casting solution; Step 4: The casting solution obtained in Step 3 is used to form a film by casting to obtain a sulfonated polyaryletherketone sulfone / protonated polyheptamethine imide composite proton exchange membrane.

[0008] In the above scheme, the synthesis method of protonated polyheptamethrin imide (H-PHI) in step 1 is as follows: Under nitrogen protection, sodium chloride and melamine were mixed at a mass ratio of 8:1 to 12:1 and reacted in a tube furnace at 550 to 600°C for 3 hours with a heating rate of 0.5 to 2°C / min. After the reaction was completed, the mixture was cooled to room temperature, filtered, and vacuum dried at 80°C for 12 hours to obtain Na-PHI. The Na-PHI was mixed with hydrochloric acid and reacted, then ultrasonically treated for 40 minutes under conventional ultrasonic conditions, and dried in a 60°C oven for 24 hours to obtain H-PHI.

[0009] In the above scheme, the preparation method of the sulfonated polyarylether ketone sulfone (SPAEKS) solution in step 2 is as follows: Sulfonated polyarylether ketone sulfone is dissolved in a solvent and heated and stirred magnetically at 80°C until completely dissolved to form a homogeneous solution; the solvent is one of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

[0010] In the above scheme, the preparation method of the casting solution in step 3 is as follows: Protonated polyheptamethine imide was added to a sulfonated polyarylether ketone sulfone solution and sonicated for 1-3 hours under conventional ultrasonic conditions. Then, the solution was magnetically stirred at 80°C for 12-15 hours to obtain a uniformly dispersed casting solution. The mass ratio of sulfonated polyarylether ketone sulfone to protonated polyheptamethine imide was 1:0.005-0.02.

[0011] In the above scheme, step 4 specifically involves the following steps: The casting solution is poured into a horizontally placed glass mold and dried in a vacuum oven at 80°C for 24–36 hours. After cooling to room temperature, the membrane is removed from the mold in deionized water. The membrane is then immersed in an acid solution and rinsed with deionized water until neutral, yielding a sulfonated polyaryletherketone sulfone / protonated polyheptamethine imide composite proton exchange membrane. This membrane is used for proton conductivity testing and battery performance testing. The membrane used for mechanical performance testing does not require acid immersion after removal and can be tested directly.

[0012] The sulfonated polyarylether ketone sulfone described above is prepared as follows: Under a nitrogen atmosphere, sulfonated dichlorodiphenyl sulfone, bisphenol A, and 4,4'-difluorobenzophenone are added to a reactor, wherein the sum of the molar amounts of sulfonated dichlorodiphenyl sulfone and 4,4'-difluorobenzophenone equals the molar amount of bisphenol A. Then, sulfolane solvent, a dehydrating agent (benzene or toluene), and anhydrous potassium carbonate salt are added. The mixture is first refluxed at 125-130°C for 4-6 hours. After separating the dehydrating agent, the temperature is raised to 175-180°C and the reaction continues for another 4-6 hours. After the reaction is complete, the viscous product is poured into distilled water, the product is cut into small pieces, and boiled in boiling water to thoroughly remove impurities. Finally, it is vacuum dried at 80°C for 24 hours to obtain sulfonated polyarylether ketone sulfone.

[0013] In the above scheme, by controlling the solid content of the casting solution, the thickness of the final composite proton exchange membrane is 20~25 μm.

[0014] The sulfonated polyaryletherketone sulfone / protonated polyheptamethine imide composite membrane comprises a sulfonated polyaryletherketone sulfone matrix and protonated polyheptamethine imide dispersed therein, and the composite membrane has proton conductivity and mechanical load-bearing capacity.

[0015] The technical mechanism of this invention lies in the following: This invention solves the problem of insufficient proton sources in the polyheptamethrinimide structure through a protonation strategy, and further utilizes molecular engineering to construct a dense and continuous hydrogen bond network, providing proton hopping sites to participate in the proton conduction process. Secondly, as a porous material, protonated polyheptamethrinimide provides transport pathways for protons through its pores. Furthermore, the strong covalent framework between PHI layers provides structural rigidity. This dual-mode synergistic structure of "weak bond transport, strong bond support" reconciles the contradiction between proton conduction and mechanical properties at the molecular level. Together, these structures enable the composite film to achieve a balance between proton conduction performance and mechanical strength.

[0016] The beneficial effects of this invention are as follows: The preparation method of the present invention has a short process step, mild reaction conditions, and does not rely on special equipment such as high-pressure reaction throughout the process, making it easy to scale up production.

[0017] This invention introduces the two-dimensional porous nanocarbon-nitrogen material H-PHI into the field of proton exchange membranes, providing an effective solution for simultaneously improving the proton conduction performance and mechanical properties of proton exchange membranes.

[0018] Benefiting from the dual-mode synergistic mechanism of "weak bond transport and strong bond carrying," the composite membrane of this invention achieves both high proton conductivity and good mechanical properties. Under conditions of 80°C and 100% relative humidity, compared with the pure SPAEKS membrane of Comparative Example 1 (in-plane proton conductivity 0.0805 S cm⁻¹), the composite membrane exhibits similar performance. -1 Peak power density 253 mW cm⁻¹ -2 Compared to the tensile strength of 30.0 MPa, the in-plane proton conductivity of the composite membrane in Example 2 of this invention (0.2447 S cm⁻¹) is significantly higher. -1 The peak power density (1095 mW / cm³) has increased by nearly 204%. -2 The tensile strength (50.5 MPa) increased by nearly 333%, and the tensile strength increased by about 68%, achieving unexpected technical results. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the synthetic route for sulfonated polyarylether ketone sulfone in this invention; Figure 2 The graphs show the in-plane proton conductivity of the proton exchange membranes prepared in Examples 1-4 and Comparative Example 1 of this invention in the range of 30-80°C. Figure 3The stress-strain curves are shown for the proton exchange membranes prepared in Examples 1-4 and Example 1 of this invention. Figure 4 The graphs show the polarization and power density curves of the single cells assembled in Example 2 and Comparative Example 1 of this invention under conditions of 80°C and 100% relative humidity. The horizontal axis represents current density (mA / cm²). -2 The left vertical axis represents voltage (V), and the right vertical axis represents power density (mW / cm²). -2 ). Detailed Implementation

[0020] The embodiments of the present invention will be described in detail below. These embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0021] Unless otherwise specified, all reagents and consumables used in the following examples and comparative examples were purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and techniques used were conventional methods and techniques in the art. Example 1

[0022] A method for preparing a sulfonated polyaryletherketone sulfone / protonated polyheptamethine imide composite proton exchange membrane, the specific steps of which are as follows: Under a nitrogen atmosphere, 0.006 mol (2.9475 g) of sulfonated dichlorodiphenyl sulfone, 0.02 mol (4.5658 g) of bisphenol A, and 0.014 mol (3.0548 g) of 4,4'-difluorobenzophenone were added to a three-necked flask. Then, sulfolane (21.23 mL) as solvent, toluene (20 mL) as a dehydrating agent, and anhydrous potassium carbonate (5.5280 g) as a salt-forming agent were added. The mixture was first refluxed at 125 °C for 4 hours. After the dehydrating agent was released, the temperature was raised to 175 °C and the reaction continued for 6 hours. After the reaction was completed, the viscous product was poured into distilled water, the product was cut into small pieces, and boiled in boiling water to thoroughly remove impurities. Finally, it was dried under vacuum at 80 °C for 24 hours to obtain sulfonated polyarylether ketone sulfone.

[0023] 10 g of sodium chloride and 1 g of melamine were placed in a tube furnace, and nitrogen gas was introduced at a flow rate of 150 mL / min for protection. The sample was heated to 600 °C at a heating rate of 1 °C / min and held at 600 °C for 3 hours. After cooling to room temperature, the sample was filtered and dried in a vacuum oven at 80 °C for 12 hours to obtain Na-PHI. Na-PHI was mixed with 6 mol / L hydrochloric acid and reacted, then ultrasonically treated at 100 W power in an ultrasonic cleaner for 40 minutes, and finally dried in a vacuum oven at 60 °C for 24 hours to obtain H-PHI.

[0024] Weigh 0.3 g of sulfonated polyarylether ketone sulfone into a small beaker, add 5 mL of N-methylpyrrolidone (NMP), and stir for 24 hours at 80 °C and 650 r / min with magnetic stirring to obtain a homogeneous solution.

[0025] 0.0015 g of protonated polyheptamethrin imide was dissolved in 5 mL of N-methylpyrrolidone (NMP) and ultrasonically dispersed for 2 hours at 100 W in a constant temperature water bath at 25 °C. The dispersed solution was then poured into a sulfonated polyarylether ketone sulfone solution and mixed. The mixture was stirred at 80 °C and 650 r / min magnetic stirring for 13 hours to obtain the casting solution. The mass ratio of sulfonated polyarylether ketone sulfone to protonated polyheptamethrin imide was 1:0.005.

[0026] The above casting solution was poured into a 100 cm³ volume. 2 The membrane was dried on a glass plate in a vacuum oven at 80°C for 24 hours, cooled to room temperature, and then stripped in deionized water. To ensure complete protonation of the sulfonic acid groups in the membrane and improve proton conductivity, the membrane was then immersed in a 2 mol / L sulfuric acid solution for 24 hours. After removal, it was rinsed with deionized water until the surface was neutral, thus obtaining a sulfonated polyaryletherketone sulfone / protonated polyheptamethine imide composite proton exchange membrane, which was used for proton conductivity testing. The membrane used for mechanical performance testing did not require acid soaking after stripping and was tested directly.

[0027] The proton exchange membrane prepared in Example 1 was subjected to performance testing: the membrane thickness was 21 μm. The in-plane proton conductivity was 0.0696 S cm⁻¹ under conditions of 100% relative humidity and a temperature range of 30–80°C. -1 ~0.1801 S cm -1 At 25℃, the tensile strength is 40 MPa. Figure 2 The in-plane proton conductivity curve of the membrane prepared in this embodiment is shown. Figure 3 The stress-strain curve of the membrane is shown. Example 2

[0028] Under a nitrogen atmosphere, 0.006 mol (2.9475 g) of sulfonated dichlorodiphenyl sulfone, 0.02 mol (4.5658 g) of bisphenol A, and 0.014 mol (3.0548 g) of 4,4'-difluorobenzophenone were added to a three-necked flask. Then, sulfolane (21.23 mL) as solvent, toluene (20 mL) as a dehydrating agent, and anhydrous potassium carbonate (5.5280 g) as a salt-forming agent were added. The mixture was first refluxed at 125 °C for 4 hours. After the dehydrating agent was released, the temperature was raised to 175 °C and the reaction continued for 6 hours. After the reaction was completed, the viscous product was poured into distilled water, the product was cut into small pieces, and boiled in boiling water to thoroughly remove impurities. Finally, it was dried under vacuum at 80 °C for 24 hours to obtain sulfonated polyarylether ketone sulfone.

[0029] 10 g of sodium chloride and 1 g of melamine were placed in a tube furnace, and nitrogen gas was introduced at a flow rate of 150 mL / min for protection. The sample was heated to 600 °C at a heating rate of 1 °C / min and held at 600 °C for 3 hours. After cooling to room temperature, the sample was filtered and dried in a vacuum oven at 80 °C for 12 hours to obtain Na-PHI. Na-PHI was mixed with 6 mol / L hydrochloric acid and reacted, then ultrasonically treated at 100 W power in an ultrasonic cleaner for 40 minutes, and dried in a vacuum oven at 60 °C for 24 hours to obtain H-PHI.

[0030] Weigh 0.3 g of sulfonated polyarylether ketone sulfone into a small beaker, add 5 mL of N-methylpyrrolidone (NMP), and stir for 24 hours at 80 °C and 650 r / min with magnetic stirring to obtain a homogeneous solution.

[0031] 0.003 g of protonated polyheptamethrin imide was dissolved in 5 mL of N-methylpyrrolidone (NMP) and ultrasonically dispersed for 2 hours at 100 W in a constant temperature water bath at 25 °C. The dispersed solution was then mixed with a sulfonated polyarylether ketone sulfone solution and stirred at 80 °C and 650 r / min magnetic stirring for 13 hours to obtain the casting solution. The mass ratio of sulfonated polyarylether ketone sulfone to protonated polyheptamethrin imide was 1:0.01.

[0032] The casting solution obtained above was poured into a 100 cm³ volume. 2 The membrane was dried on a glass plate in a vacuum oven at 80°C for 24 hours, cooled to room temperature, and then stripped in deionized water. The membrane was then immersed in a 2 mol / L sulfuric acid solution for 24 hours, removed, and rinsed with deionized water until the surface was neutral, thus obtaining a sulfonated polyarylether ketone sulfone / protonated polyheptamethrin imide composite proton exchange membrane. This membrane is used for proton conductivity testing and battery performance testing. The membrane used for mechanical performance testing does not require acid soaking after stripping and can be tested directly.

[0033] The proton exchange membrane prepared in Example 2 was subjected to performance testing: the membrane thickness was 22 μm. Under conditions of 100% relative humidity and a temperature range of 30–80°C, the in-plane proton conductivity was 0.0971 S cm⁻¹. -1 ~0.2447 S cm -1 At 25℃, the tensile strength is 50.5 MPa. Figure 2 The in-plane proton conductivity curve of the membrane prepared in this embodiment is shown. Figure 3 The stress-strain curve of the membrane is shown.

[0034] The composite proton exchange membrane from Example 2 was assembled into a hydrogen-oxygen fuel cell. The specific operating steps were as follows: The catalyst was uniformly sprayed onto both sides of the membrane using a sprayer (SP202), with a catalyst loading of 0.5 mg / cm³. -2 After the catalyst is dried, the catalyst-coated membrane is assembled into a membrane electrode assembly (MEA), and its performance is tested using an 850e fuel cell test system. The catalyst consists of Nafion (20% by mass) and Pt / C (40% by mass of Pt).

[0035] Battery test results: At 80℃ and 100% relative humidity, the peak power density is 1095 mW / cm². -2 The current density reaches 3547 mA cm⁻¹ -2 . Figure 4 The power density curve of the membrane is shown. Example 3

[0036] Under a nitrogen atmosphere, 0.006 mol (2.9475 g) of sulfonated dichlorodiphenyl sulfone, 0.02 mol (4.5658 g) of bisphenol A, and 0.014 mol (3.0548 g) of 4,4'-difluorobenzophenone were added to a three-necked flask. Then, sulfolane (21.23 mL) as solvent, toluene (20 mL) as a dehydrating agent, and anhydrous potassium carbonate (5.5280 g) as a salt-forming agent were added. The mixture was first refluxed at 125 °C for 4 hours. After the dehydrating agent was released, the temperature was raised to 175 °C and the reaction continued for 6 hours. After the reaction was completed, the viscous product was poured into distilled water, the product was cut into small pieces, and boiled in boiling water to thoroughly remove impurities. Finally, it was dried under vacuum at 80 °C for 24 hours to obtain sulfonated polyarylether ketone sulfone.

[0037] 10 g of sodium chloride and 1 g of melamine were placed in a tube furnace, and nitrogen gas was introduced at a flow rate of 150 mL / min for protection. The sample was heated to 600 °C at a heating rate of 1 °C / min and held at 600 °C for 3 hours. After cooling to room temperature, it was filtered and dried in a vacuum oven at 80 °C for 12 hours to obtain Na-PHI. Na-PHI was mixed with 6 mol / L hydrochloric acid and reacted, then ultrasonically treated at 100 W power in an ultrasonic cleaner for 40 minutes, and dried in a vacuum oven at 60 °C for 24 hours to obtain H-PHI.

[0038] Weigh 0.3 g of sulfonated polyarylether ketone sulfone into a small beaker, add 5 mL of N-methylpyrrolidone (NMP), and stir for 24 hours at 80 °C and 650 r / min with magnetic stirring to obtain a homogeneous solution.

[0039] 0.0045 g of protonated polyheptamethrin imide was dissolved in 5 mL of N-methylpyrrolidone (NMP) and ultrasonically dispersed for 2 hours at 100 W in a constant temperature water bath at 25 °C. The dispersed solution was then mixed with a sulfonated polyarylether ketone sulfone solution and stirred at 80 °C and 650 r / min magnetic stirring for 13 hours to obtain the casting solution. The mass ratio of sulfonated polyarylether ketone sulfone to protonated polyheptamethrin imide was 1:0.015.

[0040] The casting solution obtained above was poured into a 100 cm³ volume. 2 The membrane was dried on a glass plate in a vacuum oven at 80°C for 24 hours. After cooling to room temperature, it was stripped in deionized water. The membrane was then immersed in a 2 mol / L sulfuric acid solution for 24 hours. After removal, it was rinsed with deionized water until the surface was neutral, thus obtaining a sulfonated polyarylether ketone sulfone / protonated polyheptamethrin imide composite proton exchange membrane. This membrane was used for proton conductivity testing. The membrane used for mechanical property testing did not require acid soaking after stripping and was tested directly.

[0041] The proton exchange membrane prepared in Example 3 was subjected to performance testing: the membrane thickness was 24 μm. Under conditions of 100% relative humidity and a temperature range of 30–80°C, the in-plane proton conductivity was 0.0836 S cm⁻¹. -1 ~0.2214 S cm -1 At 25℃, the tensile strength is 47 MPa. Figure 2 The in-plane proton conductivity curve of the membrane prepared in this embodiment is shown. Figure 3 The stress-strain curve of the membrane is shown. Example 4

[0042] Under a nitrogen atmosphere, 0.006 mol (2.9475 g) of sulfonated dichlorodiphenyl sulfone, 0.02 mol (4.5658 g) of bisphenol A, and 0.014 mol (3.0548 g) of 4,4'-difluorobenzophenone were added to a three-necked flask. Then, sulfolane (21.23 mL) as solvent, toluene (20 mL) as a dehydrating agent, and anhydrous potassium carbonate (5.5280 g) as a salt-forming agent were added. The mixture was first refluxed at 125 °C for 4 hours. After the dehydrating agent was released, the temperature was raised to 175 °C and the reaction continued for 6 hours. After the reaction was completed, the viscous product was poured into distilled water, the product was cut into small pieces, and boiled in boiling water to thoroughly remove impurities. Finally, it was dried under vacuum at 80 °C for 24 hours to obtain sulfonated polyarylether ketone sulfone.

[0043] 10 g of sodium chloride and 1 g of melamine were placed in a tube furnace, and nitrogen gas was introduced at a flow rate of 150 mL / min for protection. The sample was heated to 600 °C at a heating rate of 1 °C / min and held at 600 °C for 3 hours. After cooling to room temperature, the sample was filtered and dried in a vacuum oven at 80 °C for 12 hours to obtain Na-PHI. Na-PHI was mixed with 6 mol / L hydrochloric acid and reacted, then ultrasonically treated at 100 W power in an ultrasonic cleaner for 40 minutes, and dried in a vacuum oven at 60 °C for 24 hours to obtain H-PHI.

[0044] Weigh 0.3 g of sulfonated polyarylether ketone sulfone into a small beaker, add 5 mL of N-methylpyrrolidone (NMP), and stir for 24 hours at 80 °C and 650 r / min with magnetic stirring to obtain a homogeneous solution.

[0045] 0.006 g of protonated polyheptamethrin imide was dissolved in 5 mL of N-methylpyrrolidone (NMP) and ultrasonically dispersed for 2 hours at 100 W in a constant temperature water bath at 25 °C. The dispersed solution was then mixed with a sulfonated polyarylether ketone sulfone solution and stirred at 80 °C and 650 r / min magnetic stirring for 13 hours to obtain the casting solution. The mass ratio of sulfonated polyarylether ketone sulfone to protonated polyheptamethrin imide was 1:0.02.

[0046] The casting solution obtained above was poured into a 100 cm³ volume. 2 The membrane was dried on a glass plate in a vacuum oven at 80°C for 24 hours. After cooling to room temperature, it was stripped in deionized water. The membrane was then immersed in a 2 mol / L sulfuric acid solution for 24 hours. After removal, it was rinsed with deionized water until the surface was neutral, thus obtaining a sulfonated polyarylether ketone sulfone / protonated polyheptamethrin imide composite proton exchange membrane. This membrane was used for proton conductivity testing. The membrane used for mechanical property testing did not require acid soaking after stripping and was tested directly.

[0047] The proton exchange membrane prepared in Example 4 was subjected to performance testing: the membrane thickness was 24 μm. The in-plane proton conductivity was 0.0728 S cm⁻¹ under conditions of 100% relative humidity and a temperature range of 30–80°C. -1 ~0.1827 S cm -1 At 25℃, the tensile strength is 37 MPa. Figure 2 The in-plane proton conductivity curve of the membrane prepared in this embodiment is shown. Figure 3 The stress-strain curve of the membrane is shown.

[0048] Comparative Example 1 Under a nitrogen atmosphere, 0.006 mol (2.9475 g) of sulfonated dichlorodiphenyl sulfone, 0.02 mol (4.5658 g) of bisphenol A, and 0.014 mol (3.0548 g) of 4,4'-difluorobenzophenone were added to a three-necked flask. Then, sulfolane (21.23 mL) as solvent, toluene (20 mL) as a dehydrating agent, and anhydrous potassium carbonate (5.5280 g) as a salt-forming agent were added. The mixture was first refluxed at 125 °C for 4 hours. After the dehydrating agent was released, the temperature was raised to 175 °C and the reaction continued for 6 hours. After the reaction was completed, the viscous product was poured into distilled water, the product was cut into small pieces, and boiled in boiling water to thoroughly remove impurities. Finally, it was dried under vacuum at 80 °C for 24 hours to obtain sulfonated polyarylether ketone sulfone.

[0049] Take 0.3 g of sulfonated polyarylether ketone sulfone in a small beaker, add 5 mL of N-methylpyrrolidone (NMP), and stir at 80℃ and 650 r / min magnetically for 24 hours to obtain a homogeneous solution. Stir at 80℃ and 650 r / min magnetically for 13 hours to obtain the casting solution.

[0050] The above casting solution was poured into a 100 cm³ volume. 2 The membrane was dried on a glass plate in a vacuum oven at 80°C for 24 hours, cooled to room temperature, and then stripped in deionized water. The membrane was then immersed in a 2 mol / L sulfuric acid solution for 24 hours, removed, and rinsed with deionized water until the surface was neutral, thus obtaining the sulfonated polyarylether ketone sulfone proton exchange membrane. This membrane is used for proton conductivity testing and battery performance testing. The membrane used for mechanical performance testing does not require acid soaking after stripping and can be tested directly.

[0051] The proton exchange membrane prepared in Comparative Example 1 was subjected to performance testing: the membrane thickness was 20 μm. Under conditions of 100% relative humidity and within the temperature range of 30–80 °C, the in-plane proton conductivity was 0.0279 S cm⁻¹. -1 ~0.0805 S cm -1 At 25℃, the tensile strength is 30 MPa. Figure 2The in-plane proton conductivity curve of the membrane prepared in this comparative example is shown. Figure 3 The stress-strain curve of the membrane is shown.

[0052] The sulfonated polyarylether ketone sulfone proton exchange membrane from Comparative Example 1 was assembled into a hydrogen-oxygen fuel cell. The specific operating steps were as follows: the catalyst was uniformly sprayed onto both sides of the membrane using a sprayer (SP202), with a catalyst loading of 0.5 mg·cm³. -2 After the catalyst is dried, the catalyst-coated membrane is assembled into a membrane electrode assembly (MEA), and its performance is tested using an 850e fuel cell test system. The catalyst consists of Nafion (20% by mass) and Pt / C (40% by mass of Pt).

[0053] Battery performance test results: Under conditions of 80℃ and 100% relative humidity, the peak power density is 253 mW / cm². -2 The current density reaches 848 mA·cm. -2 . Figure 4 The power density curve of the membrane is shown.

[0054] Figure 1 This is a schematic diagram of the synthetic route for sulfonated polyarylether ketone sulfone in this invention.

[0055] Figure 2 This is a graph showing the in-plane proton conductivity as a function of temperature for the proton exchange membranes prepared in Examples 1-4 and Comparative Example 1 of this invention. As can be seen from the graph, within the temperature range of 30-80°C and at 100% relative humidity, the in-plane proton conductivity of the proton exchange membranes prepared in Examples 1-4 is higher than that of Comparative Example 1. Among them, Example 2 exhibits the highest in-plane proton conductivity, reaching 0.2447 S cm⁻¹ at 80°C and 100% relative humidity. -1 .

[0056] Figure 3 The figures show the stress-strain curves of the proton exchange membranes prepared in Examples 1-4 and Comparative Example 1 of this invention. As can be seen from the figures, the tensile strength of the proton exchange membranes prepared in Examples 1-4 is higher than that in Comparative Example 1.

[0057] Figure 4 The figures show the battery polarization curves and power density curves for Example 2 and Comparative Example 1. The peak power density and current density of Example 2 are significantly higher than those of Comparative Example 1. Under conditions of 80°C and 100% relative humidity, the peak power density of Example 2 is 1095 mW / cm². -2 The current density is 3547 mA cm⁻¹ -2 The peak power density of Comparative Example 1 is 253 mW / cm². -2 The current density is 848 mA cm⁻¹ -2The peak power density and current density of Example 2 are both higher than those of Comparative Example 1.

[0058] The results of the above examples show that, compared with Comparative Example 1, the composite proton exchange membrane with protonated polyheptamethine imide exhibits improved proton conductivity and fuel cell power density, and its tensile strength is higher than that of Comparative Example 1 in the range of 0.5~2 wt% protonated polyheptamethine imide addition. Among them, the composite membrane prepared in Example 2 achieved the best overall performance with a protonated polyheptamethine imide addition of 1 wt%, exhibiting the highest in-plane proton conductivity (0.2447 Scm). -1 ), and the highest peak power density (1095 mW cm⁻¹) -2 And the highest tensile strength (50.5 MPa)

[0059] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a sulfonated polyaryletherketone sulfone / protonated polyheptamethineimide composite proton exchange membrane, characterized in that, Includes the following steps: Step 1: Synthesize protonated polyheptamethrin imide (H-PHI); Step 2: Prepare a sulfonated polyaryletherketone sulfone (SPAEKS) solution; Step 3: Add H-PHI to the SPAEKS solution obtained in Step 2, and control the mass ratio of sulfonated polyarylether ketone sulfone to protonated polyheptamethrin imide to be 1:0.005-0.

02. First, ultrasonically disperse for 1-3 hours, and then stir for 12-15 hours to obtain the casting solution. Step 4: The casting solution obtained in Step 3 is used to form a film by casting to obtain a sulfonated polyaryletherketone sulfone / protonated polyheptamethine imide composite proton exchange membrane.

2. A sulfonated polyaryletherketone sulfone / protonated polyheptamethineimide composite proton exchange membrane, characterized in that, The composite membrane comprises sulfonated polyaryletherketone sulfone and protonated polyheptamethine imide, wherein the mass ratio of sulfonated polyaryletherketone sulfone to protonated polyheptamethine imide is 1:0.005 to 0.

02.

3. The preparation method according to claim 1, characterized in that, The synthesis method of H-PHI in step 1 is as follows: Sodium chloride and melamine were mixed in a mass ratio of 8:1 to 12:1 and reacted in a tube furnace at 550 to 600°C for 3 hours with a heating rate of 0.5 to 2°C / min. After the reaction was completed, the mixture was cooled to room temperature, filtered, and dried to obtain Na-PHI. The Na-PHI was mixed with hydrochloric acid and reacted. After ultrasonic treatment for 40 minutes, it was dried in an oven at 60°C for 24 hours to obtain H-PHI.

4. The preparation method according to claim 3, characterized in that, The mass ratio of sodium chloride to melamine is 10:1, the reaction temperature is 600℃, and the heating rate is 1℃ / min.

5. The preparation method according to claim 1, characterized in that, The preparation method of the sulfonated polyarylether ketone sulfone solution in step 2 is as follows: The sulfonated polyarylether ketone sulfone is mixed with a solvent and dissolved under magnetic heating and stirring at 80°C to form a homogeneous solution; the solvent is one of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

6. The preparation method according to claim 1, characterized in that, The specific steps for step 4 are as follows: The casting solution is poured into a horizontally placed glass plate mold and dried in a vacuum oven at 80°C for 24–36 hours. After cooling to room temperature, the membrane is removed by deionization in deionized water. The membrane is then soaked in an acid solution and rinsed with deionized water until neutral to obtain the composite proton exchange membrane.

7. The preparation method according to claim 1, characterized in that, The preparation method of the sulfonated polyarylether ketone sulfone is as follows: Under a nitrogen atmosphere, sulfonated dichlorodiphenyl sulfone, bisphenol A, and 4,4'-difluorobenzophenone (where the sum of the moles of sulfonated dichlorodiphenyl sulfone and 4,4'-difluorobenzophenone equals the moles of bisphenol A) are added to the reactor. Then, sulfolane solvent, a dehydrating agent (benzene or toluene), and anhydrous potassium carbonate salt are added. The mixture is first refluxed at 125–130°C for 4–6 hours. After the dehydrating agent is released, the temperature is raised to 175–180°C, and the reaction continues for 4–6 hours. After the reaction is completed, the product is poured into distilled water, then the product is cut into small pieces, boiled in boiling water, and finally vacuum dried at 80°C for 24 hours to obtain sulfonated polyarylether ketone sulfone.

8. The composite proton exchange membrane according to claim 2, characterized in that, The thickness of the composite film is 20-25 μm; and the in-plane proton conductivity under the condition of 80℃, 100% relative humidity is not less than 0.1801 S cm -1 ; and the tensile strength at 25℃ is greater than or equal to 35 MPa.

9. A fuel cell, characterized in that, It includes the composite proton exchange membrane as described in claim 2 or 8.

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