Preparation method of high-performance vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membrane

Abstract

The application relates to a preparation method of a high-performance vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membrane, and belongs to the field of high-temperature fuel cells. Method: 3,3'-diamino benzidine and 4,4'-diphenyl ether dicarboxylic acid are dissolved in PPA to prepare OPBI; vitamin C phosphate magnesium / OPBI composite membranes are prepared by using OPBI, DMAc and MAP; the vitamin C phosphate magnesium / OPBI composite membranes are immersed in a phosphoric acid solution to obtain a final product. The composite high-temperature proton exchange membrane prepared by the application realizes the transfer of protons, so that the membrane exhibits excellent proton conductivity and improves the stability of the membrane. More hydrogen bonds and more covalent bonds are widely formed between vitamin C phosphate magnesium and the OPBI skeleton, and the interface compatibility is excellent, so that the mechanical properties of the membrane are improved. The composite high-temperature proton exchange membrane in the application has high mechanical properties, proton conductivity and oxidation resistance under high-temperature anhydrous conditions.

Description

Technical Field

[0001] The present invention belongs to the field of high-temperature fuel cells, and in particular relates to a method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane. Background Art

[0002] Fuel cells, a highly efficient energy conversion technology that directly converts chemical energy into electrical energy, are demonstrating enormous potential for application across a wide range of sectors. From transportation to household electricity to aerospace, fuel cells, with their high efficiency, environmental friendliness, and diverse fuel sources, are considered a crucial component of future energy solutions. In terms of market demand, a growing awareness of environmental protection and energy sustainability is driving the demand for clean energy, further driving the fuel cell market. As a core component of fuel cells, proton exchange membranes play a key role in cell performance.

[0003] An ideal high-temperature proton exchange membrane needs to exhibit high proton conductivity while simultaneously preventing electron transport and crossover of hydrogen and oxygen. Furthermore, the proton exchange membrane material must maintain chemical stability in an environment containing ·HO and ·HOO radicals, maintain good thermal stability throughout the entire high-temperature fuel cell operating range (100-200°C), and possess a certain level of mechanical strength. Therefore, improving the proton conductivity, oxidative stability, and mechanical properties of high-temperature proton exchange membranes is crucial. Summary of the Invention

[0004] The present invention aims to solve the above technical problems and provide a method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane.

[0005] A method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane is carried out according to the following steps:

[0006] 1. Preparation of polyarylether benzimidazole:

[0007] In a 150 ml three-necked round-bottom flask, 3,3'-diaminobenzidine and 4,4'-diphenyl ether dicarboxylic acid were dissolved in PPA (polyphosphoric acid), heated and stirred under nitrogen protection, and then continued to heat and stir until the solution became viscous. The solution was then poured into deionized water, and the product was collected and washed with sodium bicarbonate alkaline solution until neutral, dried, and then ground to obtain OPBI (polyarylene ether benzimidazole);

[0008] 2. Preparation of magnesium ascorbyl phosphate / OPBI composite film:

[0009] The above-mentioned OPBI was dissolved in DMAc (N,N-dimethylacetamide), and then magnesium ascorbyl phosphate (MAP) was added. The mixture was kept at 60°C under a nitrogen atmosphere for 24 hours, and then a film was prepared by a cast method. The film was then immersed in deionized water and removed. After drying, a magnesium ascorbyl phosphate / OPBI composite film was obtained.

[0010] 3. Preparation of composite membrane:

[0011] The above-mentioned magnesium ascorbyl phosphate / OPBI composite membrane is immersed in a phosphoric acid solution for 48 hours. After being taken out, the phosphoric acid solution on the surface of the composite membrane is wiped off with filter paper. After drying, a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane is obtained, thereby completing the preparation method.

[0012] Furthermore, in step 1, the amount of 3,3'-diaminobenzidine used is 4.29 g, the amount of 4,4'-diphenyl ether dicarboxylic acid used is 5.16 g, and the amount of PPA used is 89 g.

[0013] Furthermore, the heating and stirring in step 1: heating to 100° C. and mechanically stirring until completely dissolved.

[0014] Furthermore, the temperature is continued to be raised to 140° C. as described in step 1.

[0015] Furthermore, the drying described in steps 1, 2 and 3 is carried out by drying in a vacuum oven at 60° C. for 24 h.

[0016] Furthermore, the structural formula of OPBI in step 1 is:

[0017]

[0018] Furthermore, in step 2, the amount of OPBI used is 1 g, the amount of DMAc used is 20 ml, and the amount of magnesium ascorbyl phosphate used is 0.07-0.45 g.

[0019] Furthermore, the phosphoric acid solution in step 3 is 85w% phosphoric acid solution.

[0020] The high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane prepared in the present invention is + Replacement of Mg 2+, and a high-density hydrogen bond network is achieved under low PA doping, achieving the continuity of proton transfer, so that the phosphoric acid-doped composite membrane exhibits excellent proton conductivity. Due to the excellent antioxidant properties of vitamin C phosphate itself, the antioxidant stability of the polymer electrolyte composite membrane is further improved. More hydrogen bonds and acid-base interactions are widely formed between vitamin C phosphate and the OPBI skeleton, with excellent interface compatibility, thereby achieving the purpose of increasing the mechanical properties of the composite membrane. Therefore, the composite high-temperature proton exchange membrane prepared in the present invention is superior to the original OPBI membrane in thermal stability, mechanical energy, proton conductivity and antioxidant properties under high-temperature anhydrous conditions.

[0021] The invention is suitable for the preparation of a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Graphs showing the proton conductivity of the products in the comparative example and examples 1 to 5;

[0023] Figure 2 The antioxidant stability curves of the products in the comparative example and Examples 1 to 5 are shown;

[0024] Figure 3 Graphs showing stress-strain curves of the products in comparative example and examples 1 to 5. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0026] Specific embodiment 1: This embodiment is a method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane, which is carried out according to the following steps:

[0027] 1. Preparation of polyarylether benzimidazole:

[0028] In a 150 ml three-necked round-bottom flask, 3,3'-diaminobenzidine and 4,4'-diphenyl ether dicarboxylic acid were dissolved in PPA, heated and stirred under nitrogen protection, and then continued to heat and stir until the solution became viscous. The solution was then poured into deionized water, and the product was collected and washed with sodium bicarbonate alkaline solution until neutral, dried, and then ground to obtain OPBI;

[0029] 2. Preparation of magnesium ascorbyl phosphate / OPBI composite film:

[0030] The above-mentioned OPBI was dissolved in DMAc, and then magnesium ascorbyl phosphate was added, and the mixture was kept at 60°C under a nitrogen atmosphere for 24 hours. A film was prepared by a cast method, and then the film was immersed in deionized water and removed. After drying, a magnesium ascorbyl phosphate / OPBI composite film was obtained;

[0031] 3. Preparation of composite membrane:

[0032] The above-mentioned magnesium ascorbyl phosphate / OPBI composite membrane is immersed in a phosphoric acid solution for 48 hours. After being taken out, the phosphoric acid solution on the surface of the composite membrane is wiped off with filter paper. After drying, a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane is obtained, thereby completing the preparation method.

[0033] The preparation process of OPBI in step 1 of this embodiment is illustrated as follows using the structural formula:

[0034]

[0035] The magnesium ascorbyl phosphate / OPBI composite film obtained in step 2 of this embodiment is stored in a dry container.

[0036] The high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane obtained in step three of this embodiment is stored in a dry container.

[0037] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the amount of 3,3'-diaminobenzidine used in step 1 is 4.29 g, the amount of 4,4'-diphenyl ether dicarboxylic acid used is 5.16 g, and the amount of PPA used is 89 g. The other steps and parameters are the same as those in specific embodiment 1.

[0038] Specific embodiment 3: This embodiment differs from specific embodiment 1 in that the heating and stirring in step 1 is: heating to 100°C and mechanically stirring until completely dissolved. Other steps and parameters are the same as those in specific embodiment 1.

[0039] Specific embodiment 4: This embodiment differs from specific embodiment 1 in that the temperature is continued to be raised to 140° C. in step 1. Other steps and parameters are the same as those in specific embodiment 1.

[0040] Specific embodiment 5: This embodiment differs from specific embodiment 1 in that the drying in steps 1, 2, and 3 is carried out in a vacuum oven at 60° C. for 24 hours. Other steps and parameters are the same as those in specific embodiment 1.

[0041] Specific embodiment 6: This embodiment differs from specific embodiment 1 in that the structural formula of OPBI in step 1 is:

[0042]

[0043] Other steps and parameters are the same as those in the first embodiment.

[0044] Specific embodiment 7: This embodiment differs from specific embodiment 1 in that the amount of OPBI used in step 2 is 1 g, the amount of DMAc used is 20 ml, and the amount of magnesium ascorbyl phosphate used is 0.07-0.45 g. The other steps and parameters are the same as those in specific embodiment 1.

[0045] Specific embodiment 8: This embodiment differs from specific embodiment 1 in that the phosphoric acid solution in step 3 is 85w% phosphoric acid solution. Other steps and parameters are the same as those in specific embodiment 1.

[0046] The beneficial effects of the present invention are verified by the following examples:

[0047] Example 1:

[0048] A method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane is carried out according to the following steps:

[0049] 1. Preparation of polyarylether benzimidazole:

[0050] In a 150 ml three-necked round-bottom flask, 3,3'-diaminobenzidine and 4,4'-diphenyl ether dicarboxylic acid were dissolved in PPA, heated and stirred under nitrogen protection, and then continued to heat and stir until the solution became viscous. The solution was then poured into deionized water, and the product was collected and washed with sodium bicarbonate alkaline solution until neutral, dried, and then ground to obtain OPBI;

[0051] 2. Preparation of magnesium ascorbyl phosphate / OPBI composite film:

[0052] The above-mentioned OPBI was dissolved in DMAc, and then magnesium ascorbyl phosphate was added, and the mixture was kept at 60°C under a nitrogen atmosphere for 24 hours. A film was prepared by a cast method, and then the film was immersed in deionized water and removed. After drying, a magnesium ascorbyl phosphate / OPBI composite film was obtained;

[0053] 3. Preparation of composite membrane:

[0054] The ascorbic acid magnesium phosphate / OPBI composite membrane was immersed in a phosphoric acid solution for 48 hours, and the phosphoric acid solution on the surface of the composite membrane was wiped off with filter paper after being taken out. After drying, a high-performance ascorbic acid magnesium phosphate / polybenzimidazole composite high-temperature proton exchange membrane was obtained, thereby completing the preparation method.

[0055] The amount of 3,3'-diaminobenzidine used in step 1 is 4.29 g, the amount of 4,4'-diphenyl ether dicarboxylic acid used is 5.16 g, and the amount of PPA used is 89 g;

[0056] Heating and stirring as described in step 1: heating to 100°C and mechanically stirring until completely dissolved;

[0057] Continue heating as described in step 1: continue to increase the temperature to 140°C.

[0058] Drying in steps 1, 2 and 3: drying in a vacuum oven at 60°C for 24h;

[0059] The structural formula of OPBI in step 1 is:

[0060]

[0061] In step 2, the amount of OPBI used is 1 g, the amount of DMAc used is 20 ml, and the amount of magnesium ascorbyl phosphate used is 0.431 g;

[0062] The phosphoric acid solution in step 3: 85w% phosphoric acid solution is used.

[0063] The high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane prepared in this example is designated as OPBI-MAP-30.

[0064] Comparative Example:

[0065] In this example, the OPBI obtained in step 1 was prepared into an OPBI membrane according to existing methods.

[0066] Example 2

[0067] The difference between this embodiment and embodiment 1 is that the amount of magnesium ascorbyl phosphate used in step 2 is 0.072 g; the rest is the same as embodiment 1.

[0068] The high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane prepared in this example is designated as OPBI-MAP-5.

[0069] Example 3

[0070] The difference between this embodiment and embodiment 1 is that the amount of magnesium ascorbyl phosphate used in step 2 is 0.144 g; the rest is the same as embodiment 1.

[0071] The high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane prepared in this example is designated as OPBI-MAP-10.

[0072] Example 4

[0073] The difference between this embodiment and embodiment 1 is that the amount of magnesium ascorbyl phosphate used in step 2 is 0.216 g; the rest is the same as embodiment 1.

[0074] The high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane prepared in this example is designated as OPBI-MAP-15.

[0075] Example 5

[0076] The difference between this embodiment and embodiment 1 is that the amount of magnesium ascorbyl phosphate used in step 2 is 0.288 g; the rest is the same as embodiment 1.

[0077] The high-performance magnesium ascorbyl phosphate / impregnated polybenzimidazole composite high-temperature proton exchange membrane prepared in this example is designated as OPBI-MAP-20.

[0078] result:

[0079] Figure 1 The proton conductivity curves of the products in the comparative example and Examples 1 to 5 are shown in FIG. Figure 1 As shown in Figure 2, it shows that there is a positive relationship between temperature and proton conductivity of the membrane. The peak proton conductivity of the OPBI membrane is the highest, which is 58.94 mS cm -1 In contrast, the OPBI-MAP-30 membrane exhibited a higher conductivity of 147.41 mS cm at the same temperature. -1 This indicates that the high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membranes prepared in Examples 1 to 5 have greatly improved proton conductivity, which is significantly better than many existing high-temperature proton exchange membranes.

[0080] Figure 2 The antioxidant stability curves of the products in the comparative example and Examples 1 to 5 are shown in FIG. Figure 2 As shown, the high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membranes prepared in Examples 1 to 5 all exhibited better antioxidant stability than the OPBI membrane in the comparative example, indicating that the hydrogen bond network and acid-base interaction formed by MAP and OPBI are beneficial to hindering the attack of free radicals on the polymer main chain.

[0081] Figure 3 The stress-strain curves of the products in the comparative example and Examples 1 to 5 are as follows: Figure 3As shown, the high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membranes prepared in Examples 1 to 5 all exhibited higher tensile strength than the OPBI membrane in the comparative example. This is due to the extensive hydrogen bonding and acid-base interactions between MAP and the OPBI backbone, resulting in excellent interfacial compatibility and enhanced mechanical properties of the composite membranes.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features and materials such as vitamin C derivatives. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane, characterized in that It proceeds as follows:

1. Preparation of polyarylether benzimidazole: In a 150 ml three-necked round-bottom flask, 3,3'-diaminobenzidine and 4,4'-diphenyl ether dicarboxylic acid were dissolved in PPA. The temperature was raised and stirred under nitrogen. The temperature was then raised and stirred continuously until the solution became viscous. The solution was then poured into deionized water. The product was collected and washed with sodium bicarbonate alkaline solution until neutral. After drying, it was ground to obtain OPBI.

2. Preparation of magnesium ascorbyl phosphate / OPBI composite film: The above-mentioned OPBI was dissolved in DMAc, and then magnesium ascorbyl phosphate was added, and the mixture was kept at 60°C under a nitrogen atmosphere for 24 hours. A film was prepared by a cast method, and then the film was immersed in deionized water and removed. After drying, a magnesium ascorbyl phosphate / OPBI composite film was obtained; 3. Preparation of composite membrane: The above-mentioned magnesium ascorbyl phosphate / OPBI composite membrane is immersed in a phosphoric acid solution for 48 hours. After being taken out, the phosphoric acid solution on the surface of the composite membrane is wiped off with filter paper. After drying, a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane is obtained, thereby completing the preparation method.

2. The method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane according to claim 1, characterized in that In step 1, the amount of 3,3'-diaminobenzidine used is 4.29 g, the amount of 4,4'-diphenyl ether dicarboxylic acid used is 5.16 g, and the amount of PPA used is 89 g.

3. The method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane according to claim 1, characterized in that Heating and stirring as described in step 1: heating to 100°C and mechanically stirring until completely dissolved.

4. The method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane according to claim 1, characterized in that Continue heating as described in step 1: continue to increase the temperature to 140°C.

5. The method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane according to claim 1, characterized in that Drying in steps 1, 2 and 3: Dry in a vacuum oven at 60°C for 24 hours.

6. The method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane according to claim 1, characterized in that The structural formula of OPBI in step 1 is: 。 7. The method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane according to claim 1, characterized in that In step 2, the amount of OPBI used is 1 g, the amount of DMAc used is 20 ml, and the amount of magnesium ascorbyl phosphate used is 0.07-0.45 g.

8. The method for preparing a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane according to claim 1, characterized in that The phosphoric acid solution in step 3: 85w% phosphoric acid solution is used.

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