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

Abstract

The invention discloses a preparation method of a high-performance vitamin C magnesium phosphate / polybenzimidazole composite high-temperature proton exchange membrane, and belongs to the field of high-temperature fuel cells. The method comprises the following steps: dissolving 3, 3 '-diaminobenzidine and 4, 4'-diphenyl ether dicarboxylic acid in PPA to prepare OPBI; preparing a vitamin C magnesium phosphate / OPBI composite membrane by adopting OPBI, DMAc and MAP; and dipping the vitamin C magnesium phosphate / OPBI composite membrane in a phosphoric acid solution to obtain a final product. According to the prepared composite high-temperature proton exchange membrane, proton transfer is achieved, so that the membrane shows excellent proton conductivity, and the stability of the membrane is improved. More hydrogen bonds and more covalent bonds are widely formed between the vitamin C magnesium phosphate and the OPBI skeleton, and the excellent interface compatibility is achieved, so that the mechanical property of the film is improved. The composite high-temperature proton exchange membrane disclosed by the invention has relatively high mechanical property, proton conductivity and oxidation resistance under a high-temperature anhydrous condition.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature fuel cells, specifically relating to a method for preparing a high-performance vitamin C phosphate magnesium / 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 purpose of this invention is to solve the above-mentioned technical problems by providing a method for preparing a high-performance vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membrane.

[0005] A method for preparing a high-performance vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membrane, comprising 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). The mixture was heated and stirred under nitrogen protection, and then the temperature was increased and the stirring was continued 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. After drying, the product was ground to obtain OPBI (polyarylene ether benzimidazole).

[0008] II. Preparation of Vitamin C Phosphate Magnesium / OPBI Composite Membrane:

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

[0010] III. Preparation of Composite Membranes:

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

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

[0013] Furthermore, the heating and stirring described in step one: heat to 100°C and mechanically stir 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 mentioned in step one 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 mentioned in step three is an 85% phosphoric acid solution.

[0020] The high-performance vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membrane prepared in this invention can pass through the H of PA + Displacement of Mg 2+Furthermore, a high-density hydrogen bond network is achieved with low PA doping, ensuring continuous proton transfer and resulting in excellent proton conductivity in the phosphate-doped composite membrane. The excellent antioxidant properties of vitamin C phosphate further enhance the antioxidant stability of the polymer electrolyte composite membrane. Extensive hydrogen bonding and acid-base interactions are formed between vitamin C phosphate and the OPBI backbone, exhibiting excellent interfacial compatibility and thus increasing the mechanical properties of the composite membrane. Therefore, the composite high-temperature proton exchange membrane prepared in this invention exhibits superior thermal stability, mechanical properties, proton conductivity, and antioxidant properties compared to the original OPBI membrane under high-temperature anhydrous conditions.

[0021] This invention is applicable to the preparation of high-performance vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membranes. Attached Figure Description

[0022] Figure 1 Proton conductivity curves for the products in comparative examples and Examples 1-5;

[0023] Figure 2 The antioxidant stability curves are for the comparative examples and products in Examples 1-5;

[0024] Figure 3 The stress-strain curves are for comparative examples and products in Examples 1 to 5. Detailed Implementation

[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 Implementation Method 1: This implementation method provides a method for preparing a high-performance vitamin C phosphate magnesium / 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] II. Preparation of Vitamin C Phosphate Magnesium / OPBI Composite Membrane:

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

[0031] III. Preparation of Composite Membranes:

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

[0033] The preparation process of OPBI in step one of this embodiment is illustrated in the following structural formula:

[0034]

[0035] The vitamin C phosphate magnesium / OPBI composite membrane obtained in step two of this embodiment is stored in a dry container.

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

[0037] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the amount of 3,3'-diaminobenzidine used in step one is 4.29g, the amount of 4,4'-diphenyl ether dicarboxylic acid is 5.16g, and the amount of PPA is 89g. Other steps and parameters are the same as in Specific Implementation Method One.

[0038] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that the heating and stirring in step one is performed by heating to 100°C and mechanically stirring until completely dissolved. Other steps and parameters are the same as in Specific Implementation Method One.

[0039] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method One in that the temperature is further increased to 140°C in step one. All other steps and parameters are the same as in Specific Implementation Method One.

[0040] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method One in that the drying process described in steps one, two, and three involves drying in a vacuum oven at 60°C for 24 hours. All other steps and parameters are the same as in Specific Implementation Method One.

[0041] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method One in that the structural formula of OPBI in step one is:

[0042]

[0043] The other steps and parameters are the same as in Specific Implementation Method 1.

[0044] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method One in that the amount of OPBI used in step two is 1g, the amount of DMAc is 20ml, and the amount of magnesium vitamin C phosphate is 0.07-0.45g. Other steps and parameters are the same as in Specific Implementation Method One.

[0045] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method One in that the phosphoric acid solution mentioned in step three is an 85% wt% phosphoric acid solution. Other steps and parameters are the same as in Specific Implementation Method One.

[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 vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membrane, comprising the following steps:

[0049] I. Preparation of polyarylene ether 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. The mixture was heated and stirred under nitrogen protection, and then the temperature was increased and the stirring was continued 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, the product was 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 vitamin C phosphate was added. The mixture was kept at 60°C under a nitrogen atmosphere for 24 hours. The membrane was then prepared by the casting method, and then soaked in deionized water and removed. After drying, the magnesium vitamin C phosphate / OPBI composite membrane was obtained.

[0053] III. Preparation of Composite Membranes:

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

[0055] In step one, the amount of 3,3'-diaminobenzidine used is 4.29g, the amount of 4,4'-diphenyl ether dicarboxylic acid used is 5.16g, and the amount of PPA used is 89g.

[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 mentioned in step one is:

[0060]

[0061] In step two, the dosage of OPBI is 1g, the dosage of DMAc is 20ml, and the dosage of magnesium vitamin C phosphate is 0.431g.

[0062] The phosphoric acid solution mentioned in step three: use an 85% phosphoric acid solution.

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

[0064] Comparative example:

[0065] In this embodiment, the OPBI obtained in step one is prepared into an OPBI membrane using 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 vitamin C phosphate used in step two is 0.144g; all other aspects are the same as in 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 vitamin C phosphate used in step two is 0.288g; all other aspects are the same as in 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 For comparative examples and examples 1-5, see the proton conductivity curves; 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 exhibits higher conductivity, at the same temperature, at 147.41 mS / cm. -1 This indicates that the high-performance vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membranes prepared in Examples 1-5 significantly improve proton conductivity, a performance that is significantly superior to many existing high-temperature proton exchange membranes.

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

[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, compared with the tensile strength of the OPBI membrane in the comparative example, the high-performance vitamin C phosphate magnesium / polybenzimidazole composite high-temperature proton exchange membranes prepared in Examples 1-5 all exhibited higher tensile strength. This is because more hydrogen bonds and acid-base interactions are formed extensively between the MAP and OPBI framework, resulting in excellent interfacial compatibility and thus increasing the mechanical properties of the composite membrane.

[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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some 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 should be included within the protection scope 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, heated and stirred under nitrogen protection, and then continued to heat and stir until the solution became viscous, then poured into deionized water, and then the product was collected and washed with sodium bicarbonate alkaline solution to neutrality, dried and ground to obtain OPBI; 2. Preparation of Vitamin C Magnesium Phosphate / OPBI Composite Film: The OPBI was dissolved in DMAc, and then ascorbic acid magnesium phosphate was added, and the mixture was kept at 60° C. and in a nitrogen atmosphere for 24 hours, and then a film was prepared by a cast method, and then the film was immersed in deionized water and removed, and dried to obtain a ascorbic acid magnesium phosphate / OPBI composite film; 3. Preparation of composite membrane: The above-mentioned magnesium ascorbyl phosphate / OPBI composite membrane is immersed in a phosphoric acid solution for 48 hours, and the phosphoric acid solution on the surface of the composite membrane is wiped off with filter paper after being taken out. After drying, a high-performance magnesium ascorbyl phosphate / polybenzimidazole composite high-temperature proton exchange membrane is obtained, and the preparation method is completed.

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 The heating and stirring 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 raise 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 24h.

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 described 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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