A polymer for preparing high-temperature proton exchange membranes, its preparation method, and its application in fuel cells.

Abstract

This invention discloses a polymer for preparing high-temperature proton exchange membranes, its preparation method, and its application in fuel cells, belonging to the field of fuel cell materials and their preparation technology. This invention uses aromatic monomers and carbonyl monomers to prepare a polymer under acid catalysis. The polymer then adsorbs phosphoric acid to form a membrane, thus preparing a high-temperature proton exchange membrane. The polymer prepared by this invention has a rigid, twisted backbone structure, which forms a microporous structure. The resulting siphon effect improves phosphoric acid retention. Simultaneously, the hydrophobic side chain structure facilitates the construction of a hydrophilic / hydrophobic microphase separation structure, improving conductivity and enhancing mechanical properties. Furthermore, because the polymer's main chain backbone is a rigid, all-carbon backbone without aromatic ether bonds, it exhibits good chemical and thermal stability. Therefore, the high-temperature proton exchange membrane prepared using this polymer has the advantages of good mechanical properties, high conductivity, high phosphoric acid retention, and low cost.

Description

Technical Field

[0001] This invention relates to a polymer for preparing high-temperature proton exchange membranes, a method for preparing the same, and its application in fuel cells, belonging to the field of fuel cell materials and their preparation technology. Background Technology

[0002] Environment and energy are two major challenges facing human society today, and hydrogen energy, as a clean energy source, has attracted much attention. Fuel cells, as a technology that converts hydrogen energy into electrical energy, have become a research hotspot. Membrane materials are one of the key components of fuel cells, directly affecting the energy conversion efficiency. Compared to other membrane materials, high-temperature proton exchange membranes are receiving increasing attention due to their advantages such as high chemical reaction efficiency, high resistance to poisoning by impurities such as CO, and simple hydrothermal management.

[0003] Currently, phosphoric acid (PA)-doped polybenzimidazole proton exchange membranes (PBI / PA) have attracted much attention and extensive research due to their high electrical conductivity and chemical stability, with companies such as Advent and Danish Power Systems having already commercialized them. However, the synthesis of polybenzimidazole is complex and costly. Increasing the amount of PA also reduces the intermolecular forces of PBI molecules, leading to decreased mechanical properties. Furthermore, due to the low interaction between PA and imidazole groups, phosphoric acid is continuously lost over time, resulting in performance degradation and hindering its application.

[0004] To address the above issues, research on non-PBI / PA type high-temperature proton exchange membranes has also attracted attention. Chinese patent CN110661021B describes the preparation of high-temperature proton exchange membranes for fuel cells using aromatic monomers and basic ketone monomers polymerized under acid catalysis. This method is simple to operate, has mild reaction conditions, and low raw material costs. Chinese patent CN 115763917A describes the use of the microporous polymer PIM-1 and... High-temperature proton exchange membranes with high phosphate retention rates are obtained through mechanical blending of base (TB) polymers and the siphon effect of the microporous structure. Chinese patent CN114044884A uses terphenyl, fluorene, and N-methyl-4-piperidinone for polymerization, employing hydrophilic and hydrophobic chains to adjust the microphase separation structure and improve conductivity. However, current high-temperature proton exchange membranes still suffer from poor mechanical properties, low chemical stability, low conductivity, high phosphate loss rate, and high production costs. Developing inexpensive high-temperature proton exchange membranes with good overall performance remains a pressing need. Summary of the Invention

[0005] This invention addresses the problems of existing high-temperature proton exchange membranes, such as high preparation cost, poor chemical stability, low electrical conductivity, poor mechanical properties, and low phosphate retention rate, by providing a polymer for preparing high-temperature proton exchange membranes, a preparation method thereof, and its application in fuel cells.

[0006] The technical solution of the present invention:

[0007] One objective of this invention is to provide a polymer for preparing high-temperature proton exchange membranes, the polymer having the following structural formula:

[0008]

[0009] In the formula, n is the number of repeating polymer units, which is an integer selected from 20 to 500; R1 is H or (CH2). m CH3, where m is selected from integers from 0 to 11; Ar is an aromatic group containing 1 to 8 ring structures, preferably one or more of chain biphenyl, substituted or unsubstituted fluorenyl, and xanthyl.

[0010] Further specifying, m in R1 can be 3, 4, 5, 6, 7 or 8.

[0011] Further specifying, Ar is a chain-like biphenyl containing 2-6 ring structures. One or more of them, where R2 is H or (CH2). k CH3, where k is selected from integers from 0 to 11.

[0012] Further specifying, k in R2 can be 3, 4, 5, 6, 7 or 8.

[0013] To further specify, Ar is: One or more of them.

[0014] The second objective of this invention is to provide a method for preparing the polymer used to prepare high-temperature proton exchange membranes, wherein the method comprises: using carbonyl monomers and aromatic monomers as raw materials, performing a polymerization reaction in the presence of an organic solvent and under acid catalysis, and obtaining the polymer after post-treatment after the reaction is completed.

[0015] Further specifying, the carbonyl monomer is 7-N heteroindigo or a 7-N indigo series derivative.

[0016] Further specifying, the structural formula of the carbonyl monomer is as follows:

[0017]

[0018] In the formula, R1 is H or (CH2). m CH3, where m is selected from integers from 0 to 11.

[0019] Further specifying, the aromatic monomer is one or a mixture of several of biphenyl, terphenyl, tetraphenyl, 9,9-dimethyloxanthracene, fluorene and its derivatives.

[0020] Further specifying, aromatic monomers are One or more combinations;

[0021] In the formula, R2 is H or (CH2). k CH3, where k is selected from integers from 0 to 11.

[0022] Further specified, the molar ratio of aromatic monomer to carbonyl monomer is 1:(1 to 1.5).

[0023] Furthermore, the molar ratio of aromatic monomers to carbonyl monomers is 1:(1.05 to 1.2).

[0024] Further specified, the polymerization reaction temperature is -10 to 80°C, and the time is 0.1 to 48 hours.

[0025] Furthermore, the polymerization reaction temperature is specified to be between -5°C and 40°C.

[0026] Furthermore, the polymerization reaction temperature is specified as 0–25°C.

[0027] Furthermore, the polymerization reaction time is specified to be 0.5–5 hours.

[0028] To further specify, the specific operation process of this method is as follows:

[0029] First, the aromatic monomer and carbonyl monomer are added to a single-necked flask, and dichloromethane (DCM) and trifluoroacetic acid (TFA) are added to dissolve them;

[0030] Then, trifluoromethanesulfonic acid (TFSA) was added dropwise at 0°C to obtain the reaction solution;

[0031] Then, the reaction solution is reacted at the polymerization reaction temperature until the required viscosity is reached, resulting in a solution containing the target polymer;

[0032] Finally, the solution containing the target polymer was poured into ethanol, washed with ethanol until colorless, washed with K2CO3 solution, washed with water until neutral, filtered, and dried under vacuum at 80°C to obtain the polymer used to prepare high-temperature proton exchange membranes.

[0033] Furthermore, the monomer mass in the reaction solution accounts for 5 to 50 wt% of the acid solution mass.

[0034] Furthermore, the monomer mass in the reaction solution accounts for 20–30 wt% of the acid solution.

[0035] Furthermore, the volume ratio of TFA to TFSA is 1:(1~10).

[0036] A third objective of this invention is to provide a high-temperature proton exchange membrane, which uses the aforementioned polymer as the film-forming material.

[0037] The fourth objective of this invention is to provide a method for preparing the above-mentioned high-temperature proton exchange membrane, the method comprising the following steps:

[0038] (1) Dissolve the polymer in a solvent to prepare a 3wt% solution, filter the solution to obtain a casting solution, cast the casting solution onto a glass plate to form a film, and dry it to obtain a polymer film;

[0039] (2) The polymer membrane was immersed in a phosphoric acid solution for acid doping treatment, and then wiped dry to obtain a high-temperature proton exchange membrane.

[0040] Further specifying, the solvent in (1) is one or a mixture of several of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and tetrachloroethane.

[0041] Further specified, the drying temperature in (1) is 60 to 100°C.

[0042] Further specifying, in (2) the concentration of phosphoric acid solution is 80-90 wt%.

[0043] Further specified, (2) the soaking temperature is 20 to 120°C and the time is 1 to 48 hours.

[0044] The fifth objective of this invention is to provide an application of the above-mentioned high-temperature proton exchange membrane, specifically, the high-temperature proton exchange membrane is used as a membrane material for fuel cells.

[0045] Compared with the prior art, the present invention has the following advantages:

[0046] (1) This invention uses 7-N heteroindigo and its derivative monomers and one or more aromatic monomers as raw materials, which are dissolved in a mixed solvent of dichloromethane and trifluoroacetic acid and polymerized under acid catalysis. After the reaction is completed, the polymer is precipitated in alkaline water and then washed with water, dried, and other post-treatments to obtain a polymer with a microporous structure and no aromatic ether bonds in the main chain, which is used to prepare high-temperature proton exchange membranes. Because the main chain backbone is a rigid all-carbon backbone without aromatic ether bonds, this polymer has good chemical and thermal stability.

[0047] (2) The polymer chain skeleton prepared by the present invention is a rigid twisted skeleton structure, which will form a microporous structure. The siphon effect will increase the phosphoric acid retention rate. At the same time, the hydrophobic side chain structure is also conducive to constructing a hydrophilic / hydrophobic microphase separation structure, improving conductivity and enhancing mechanical properties, so that the high-temperature proton exchange membrane prepared by it has good mechanical properties, high conductivity and high phosphoric acid retention rate.

[0048] (3) The raw materials used to prepare the polymer in this invention are inexpensive, the preparation method is simple, and it can be prepared at room temperature without protection. The reaction conditions are mild, which solves the problem of high cost in the preparation of high-temperature proton exchange membranes and is more suitable for large-scale industrial production. Attached Figure Description

[0049] Figure 1 The 1H NMR spectrum of the polymer prepared in Example 1 (solvent: CDCl3);

[0050] Figure 2 The 1H NMR spectrum of the polymer prepared in Example 2 (solvent: CDCl3);

[0051] Figure 3 The 1H NMR spectrum of the polymer prepared in Example 5 (solvent: CDCl3);

[0052] Figure 4 The 1H NMR spectrum of the polymer prepared in Example 6 (solvent: CDCl3);

[0053] Figure 5 The 1H NMR spectrum of the polymer prepared in Example 9 (solvent: CDCl3);

[0054] Figure 6 The 1H NMR spectrum of the polymer prepared in Example 10 (solvent: CDCl3);

[0055] Figure 7 The performance test curve of the fuel cell assembled with the high-temperature proton exchange membrane prepared using the polymer obtained in Example 2 as the film-forming material at 120°C is shown.

[0056] Figure 8 The performance test curves of the fuel cell assembled with the high-temperature proton exchange membrane prepared using the polymer obtained in Example 9 as the film-forming material are shown at 120°C. Detailed Implementation

[0057] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0058] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0059] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0060] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0061] Example 1

[0062] (I) Polymer Preparation

[0063] Weigh 0.011 mol (1.78 g) of 1-methyl-7-N-heteroindigo and 0.01 mol (1.54 g) of biphenyl into a 50 mL round-bottom flask containing a magnetic stir bar. Add 2 mL of DCM and 4 mL of TFA and stir until the system is homogeneous. Slowly add 4 mL of TFSA at 0 °C with rapid stirring. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer. The 1H NMR spectrum of this polymer is shown below. Figure 1 As shown.

[0064] The polymer has the following structural formula:

[0065]

[0066] (II) Preparation of high-temperature proton exchange membranes

[0067] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0068] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the surface phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0069] Example 2

[0070] (I) Polymer Preparation

[0071] Weigh 0.011 mol (1.78 g) of 1-methyl-7-N-heteroindigo and 0.01 mol (2.3 g) of terphenyl and add them to a 50 mL round-bottom flask containing a magnetic stir bar. Add 3 mL of DCM and 6 mL of TFA and stir until the system is homogeneous. At 0 °C, slowly add 6 mL of TFSA while stirring rapidly. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer. The 1H NMR spectrum of this polymer is shown below. Figure 2 As shown.

[0072] The polymer has the following structural formula:

[0073]

[0074] (II) Preparation of high-temperature proton exchange membranes

[0075] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0076] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0077] (III) Assembly of hydrogen-oxygen fuel cells

[0078] Using the high-temperature proton exchange membrane prepared in this embodiment as the separator of the battery, the membrane battery assembly needs to be assembled first. A Pt / C (40wt%) catalyst, ionomer, isopropanol, and water are mixed and then ultrasonicated for 2 hours until uniformly dispersed to prepare a catalyst ink. The catalyst ink is then uniformly sprayed onto carbon paper using a spray gun. The composition and amount of catalyst ink on the carbon paper are identical. Then, carbon paper coated with the catalyst is placed on both sides of the membrane as a gas diffusion layer, with the catalyst facing the high-temperature proton exchange membrane. The assembled carbon paper and membrane are then assembled into a battery fixture, with H2 introduced on one side of the membrane and O2 introduced on the other. Single-cell performance is tested at different temperatures.

[0079] The assembled hydrogen-oxygen fuel cell was tested at 120°C with no back pressure and a catalyst concentration of 0.5 mg / cm³. -2 Performance tests were conducted under the following conditions, and the polarization curves are as follows: Figure 7As shown, the open-circuit voltage of the high-temperature proton exchange membrane fuel cell in Example 2 is 0.98V, as determined by polarization curve testing. This indicates low hydrogen permeation and good gas tightness of the membrane. At a current of 450mA / cm², the open-circuit voltage is [not specified]. -2 At that time, the maximum power density was 140 mW cm⁻¹ -2 .

[0080] Example 3

[0081] (I) Polymer Preparation

[0082] Weigh 0.011 mol (1.78 g) of 1-methyl-7-N-heteroindigo and 0.01 mol (3.06 g) of tetraphenylbenzene into a 50 mL round-bottom flask containing a magnetic stir bar. Add 4 mL of LDCM and 7 mL of LTFA and stir until the system is homogeneous. Slowly add 7 mL of TFSA at 0 °C with rapid stirring. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer.

[0083] The polymer has the following structural formula:

[0084]

[0085] (II) Preparation of high-temperature proton exchange membranes

[0086] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0087] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0088] Example 4

[0089] (I) Polymer Preparation

[0090] Weigh 0.011 mol (1.78 g) of 1-methyl-7-N-heteroindigo and 0.01 mol (1.94 g) of 9,9-dimethylfluorene into a 50 mL round-bottom flask containing a magnetic stir bar. Add 3 mL of LDCM and 6 mL of LTFA and stir until the system is homogeneous. At 0 °C, slowly add 6 mL of TFSA while stirring rapidly. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the solution is converted into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer.

[0091] The polymer has the following structural formula:

[0092]

[0093] (II) Preparation of high-temperature proton exchange membranes

[0094] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0095] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0096] Example 5

[0097] (I) Polymer Preparation

[0098] Weigh 0.011 mol (1.78 g) of 1-methyl-7-N-hexa-indigo and 0.01 mol (2.1 g) of 9,9-dimethyloxanthracene into a 50 mL round-bottom flask containing a magnetic stir bar. Add 3 mL of DCM and 6 mL of TFA and stir until the system is homogeneous. Slowly add 6 mL of TFSA at 0 °C with rapid stirring. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K₂CO₃ solution, wash with water until neutral, filter, and vacuum dry at 80 °C to obtain the target polymer. The 1H NMR spectrum of this polymer is shown below. Figure 3 As shown.

[0099] The polymer has the following structural formula:

[0100]

[0101] (II) Preparation of high-temperature proton exchange membranes

[0102] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0103] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0104] Example 6

[0105] (I) Polymer Preparation

[0106] Weigh 0.011 mol (1.78 g) of 7-N-indigo (0.01 mol, 2.1 g) and add them to a 50 mL pear-shaped flask containing a magnetic stir bar. Add 3 mL of LDCM and 6 mL of LTFA and stir until the system is homogeneous. Slowly add 6 mL of TFSA at 0 °C with rapid stirring. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer. The 1H NMR spectrum of this polymer is shown below. Figure 4 As shown.

[0107] The polymer has the following structural formula:

[0108]

[0109] (II) Preparation of high-temperature proton exchange membranes

[0110] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0111] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0112] Example 7

[0113] (I) Polymer Preparation

[0114] Weigh 0.011 mol (2.55 g) of 1-hexyl-7-N-heteroindigo and 0.01 mol (2.1 g) of 9,9-dimethyloxanthracene into a 50 mL pear-shaped flask containing a magnetic stir bar. Add 4 mL of LDCM and 7 mL of LTFA and stir until the system is homogeneous. Slowly add 7 mL of TFSA at 0 °C with rapid stirring. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer.

[0115] The polymer has the following structural formula:

[0116]

[0117] (II) Preparation of high-temperature proton exchange membranes

[0118] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0119] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0120] Example 8

[0121] (I) Polymer Preparation

[0122] Weigh 0.011 mol (3.48 g) of 1-dodecyl-7-N-heteroindigo and 0.01 mol (2.1 g) of 9,9-dimethyloxanthracene into a 50 mL round-bottom flask containing a magnetic stir bar. Add 4 mL of LDCM and 7 mL of LTFA and stir until the system is homogeneous. Slowly add 7 mL of TFSA at 0 °C with rapid stirring. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer.

[0123] The polymer has the following structural formula:

[0124]

[0125] (II) Preparation of high-temperature proton exchange membranes

[0126] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0127] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0128] Example 9

[0129] (I) Polymer Preparation

[0130] Weigh 0.011 mol (1.78 g) of 1-methyl-7-N-hexa-indigo, 0.005 mol (1.05 g) of 9,9-dimethyloxanthracene, and 0.005 mol (1.15 g) of terphenyl into a 50 mL piezoelectric flask containing a magnetic stir bar. Add 3 mL of LDM and 6 mL of TFA and stir until the system is homogeneous. Slowly add 6 mL of TFSA at 0 °C with rapid stirring. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer. The 1H NMR spectrum of this polymer is shown below. Figure 5 As shown.

[0131] The polymer has the following structural formula:

[0132]

[0133] (II) Preparation of high-temperature proton exchange membranes

[0134] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0135] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0136] (iv) Assembly of hydrogen-oxygen fuel cells

[0137] Using the high-temperature proton exchange membrane prepared in this embodiment as the separator of the battery, the membrane battery assembly needs to be assembled first. A Pt / C (40wt%) catalyst, ionomer, isopropanol, and water are mixed and then ultrasonicated for 2 hours until uniformly dispersed to prepare a catalyst ink. The catalyst ink is then uniformly sprayed onto carbon paper using a spray gun. The composition and amount of catalyst ink on the carbon paper are identical. Then, carbon paper coated with the catalyst is placed on both sides of the membrane as a gas diffusion layer, with the catalyst facing the high-temperature proton exchange membrane. The assembled carbon paper and membrane are then assembled into a battery fixture, with H2 introduced on one side of the membrane and O2 introduced on the other. Single-cell performance is tested at different temperatures.

[0138] The assembled hydrogen-oxygen fuel cell was tested at 180°C with no back pressure and a catalyst concentration of 0.5 mg / cm³. -2 Performance tests were conducted under the following conditions, and the polarization curves are as follows: Figure 8 As shown, the open-circuit voltage of the high-temperature proton exchange membrane fuel cell in Example 9 is 0.96V, as determined by polarization curve testing. This indicates low hydrogen permeation and good gas tightness of the membrane. At a current of 1500 mA / cm², the open-circuit voltage is [not specified].-2 At that time, the maximum power density was 495 mW cm⁻¹ -2 .

[0139] Example 10

[0140] (I) Polymer Preparation

[0141] Weigh 0.011 mol (1.78 g) of 1-methyl-7-N-hexa-indigo, 0.007 mol (1.47 g) of 9,9-dimethyloxanthracene, and 0.003 mol (0.69 g) of terphenyl into a 50 mL round-bottom flask containing a magnetic stir bar. Add 3 mL of LDM and 6 mL of TFA and stir until the system is homogeneous. Slowly add 6 mL of TFSA at 0 °C with rapid stirring. React at room temperature for 2 h to obtain a polymer solution with a certain viscosity. After dilution, the polymer is phase-transformed into a white filamentous polymer in a large amount of anhydrous ethanol. Wash with 1 M K2CO3 solution, wash with water until neutral, filter, and dry under vacuum at 80 °C to obtain the target polymer. The 1H NMR spectrum of this polymer is shown below. Figure 6 As shown.

[0142] The structural formula of polymer 10 is as follows:

[0143]

[0144] (II) Preparation of high-temperature proton exchange membranes

[0145] 0.3 g of polymer was dissolved in 10 mL of tetrachloroethane solvent in a single-necked flask to prepare a 3 wt% casting solution. After filtration, the solution was cast onto a glass plate to form a film. The solvent was dried at 80 °C to obtain the polymer film.

[0146] At 80°C, the polymer membrane is immersed in an 85wt% phosphoric acid solution to adsorb phosphoric acid. After standing for 24 hours, the membrane is removed and the phosphoric acid is wiped dry to obtain a high-temperature proton exchange membrane.

[0147] Example of effect:

[0148] I. The viscosity (η) and molecular weight (Mn) of the polymers prepared in Examples 1 to 10 above were tested.

[0149] Viscosity (η) test: Prepare a 125 mg / 25 mL polymer / N,N-dimethylacetamide solution and test it with an Ubbelohde viscometer at 30 °C.

[0150] Molecular weight (Mn) determination: Obtained using a GPC instrument. The mobile phase was N,N-dimethylformamide (DMF), and the test was conducted at 80°C. The instrument used was a Water 1515 series GPC, conducted at 35°C, with a flow rate of 1.0 mL / min. Commercially available polystyrene (PS) was used as the standard sample to plot the molecular weight standard curve. Sample preparation: 3 mg of sample was dissolved in 3 mL of mobile phase solvent, filtered through a filter tip, before loading.

[0151] The test results are shown in Table 1 below:

[0152] Table 1

[0153] Serial Number η(s) Mn Example 1 1.21 35000 Example 2 1.31 157200 Example 3 1.10 35975 Example 4 1.17 21896 Example 5 1.42 61247 Example 6 1.51 47895 Example 7 1.12 60398 Example 8 1.32 21864 Example 9 1.34 65238 Example 10 1.21 35369

[0154] II. The conductivity, acid absorption rate, tensile strength, and elongation at break of the high-temperature proton exchange membranes prepared in Examples 1 to 10 above were tested. The test results are shown in Table 2 below:

[0155] Table 2

[0156]

[0157]

[0158] III. The surface area and pore size distribution of the polymers prepared in Examples 1 to 10 were tested (obtained by N2 adsorption test). The test results are shown in Table 3 below:

[0159] Table 3:

[0160] Serial Number <![CDATA[BET surface area m 2 / g]]> Aperture concentration distribution nm Example 1 121.23 5.034 Example 2 102.14 3.015 Example 3 75.27 4.321 Example 4 157.21 7.621 Example 5 274.25 7.296 Example 6 195.54 6.345 Example 7 67.20 2.34 Example 8 47.24 3.21 Example 9 67.54 5.12 Example 10 107.67 2.36

[0161] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A polymer for preparing high-temperature proton exchange membranes, characterized in that, The polymer has the following structural formula: In the formula, n is the number of repeating polymer units, which is an integer selected from 20 to 500; R1 is H or (CH2). m CH3, where m is an integer from 0 to 5; Ar is: , , , , One or more of the following.

2. A method for preparing the polymer according to claim 1, characterized in that, The method is as follows: First, aromatic monomers and carbonyl monomers were used as raw material monomers and mixed with DCM and TFA. After complete dissolution, TFSA was added dropwise at 0°C to obtain a reaction solution. Then, the reaction solution is heated to the polymerization temperature and kept at that temperature to carry out the polymerization reaction. After the reaction is completed, the polymer is obtained through post-treatment.

3. The method for preparing the polymer according to claim 2, characterized in that, The molar ratio of aromatic monomer to carbonyl monomer is 1:(1~1.5), and the mass concentration of the raw material monomer in the acid solution is 5~50wt%. The solutes in the acid solution are TFA and TFSA, and the volume ratio of TFA to TFSA is 1:(1~10).

4. The method for preparing the polymer according to claim 2, characterized in that, The polymerization reaction temperature is -10~80℃, and the time is 0.1~48h.

5. A high-temperature proton exchange membrane, characterized in that, The polymer described in claim 1 is used as the film-forming material.

6. A method for preparing the high-temperature proton exchange membrane according to claim 5, characterized in that, include: (1) Dissolve the polymer in a solvent to prepare a casting solution, cast the casting solution into a film, and dry it to obtain a polymer film; (2) The polymer membrane is immersed in a phosphoric acid solution for acid doping treatment to obtain a high-temperature proton exchange membrane.

7. An application of the high-temperature proton exchange membrane according to claim 5, characterized in that, It is used as a membrane material for fuel cells.

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