Preparation method of double quaternary ammonium type polyion liquid / quaternary ammonium type polybenzimidazole cross-linked membrane for high-temperature proton exchange membrane
By preparing a cross-linked membrane of bisquaternary ammonium polyionic liquid and quaternary ammonium polybenzimidazole, the problem of insufficient proton conductivity and phosphoric acid retention in high-temperature proton exchange membrane fuel cells was solved, achieving higher proton conductivity and phosphoric acid retention, and improving the performance of high-temperature proton exchange membranes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2026-03-20
AI Technical Summary
Existing high-temperature proton exchange membrane fuel cells have insufficient proton conductivity and phosphoric acid retention capacity, resulting in low energy conversion efficiency and reactivity.
A composite material of a quaternary ammonium polyionic liquid and a quaternary ammonium polybenzimidazole crosslinked membrane was prepared by forming proton transport channels and enhancing acid-base interactions through silane crosslinking and acid-base doping reactions.
It improved the proton conductivity and phosphate retention rate. The proton conductivity reached 135.5 mS cm-1 at 180℃, and the phosphate retention rate reached 85.3% under anhydrous conditions at 160℃, thus enhancing the performance of the high-temperature proton exchange membrane.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer materials and fuel cells, and discloses a method for preparing a quaternary ammonium type polyionic liquid / quaternary ammonium type polybenzimidazole crosslinked membrane for high-temperature proton exchange membranes. Background Technology
[0002] Proton exchange membrane fuel cells (PEMFCs) possess numerous advantages and potential, primarily including high efficiency, low emissions, and simple structure. High-temperature PEMFCs, as a type of PEMFC, can operate at higher temperatures (120℃-200℃) without external humidification. High-temperature PEMFCs can mitigate carbon monoxide poisoning, improve impurity tolerance, enhance energy conversion efficiency, and exhibit higher reactivity and faster reaction rates. The high-temperature PEMFC is its most crucial component, acting as a proton transporter and barrier between the cathode and anode, and is receiving increasing attention from research. Summary of the Invention
[0003] The purpose of this invention is to provide a method for preparing a dual quaternary ammonium polyionic liquid / quaternary ammonium polybenzimidazole crosslinked membrane for high-temperature proton exchange membrane fuel cells. This composite membrane exhibits excellent proton conductivity, phosphoric acid retention capacity, and output power. The prepared QMPBI-PO 10 -T 90 The proton conductivity can reach 135.5 mS / cm at 180℃. -1 After 240 hours, the phosphoric acid retention rate reached 85.3% at 160°C under anhydrous conditions. This invention first provides a bis-quaternary ammonium type polyionic liquid / quaternary ammonium type polybenzimidazole crosslinked membrane for high-temperature proton exchange membranes, the composite membrane comprising the following components by mass percentage: QMPBI-O x -T y 70% [TePeAm]Br2: 30%
[0004] This invention also provides a method for preparing a bisquaternary ammonium polyionic liquid / quaternary ammonium polybenzimidazole crosslinked membrane for high-temperature proton exchange membranes, comprising the following:
[0005] Step 1: Thoroughly mix polyphosphoric acid and DAB. Then add IPA, MIPA, and P2O5 to a round-bottom flask, and pour the resulting polymer into deionized water containing sodium bicarbonate. Finally, cut the polymer into small pieces, boil, and dry to obtain MPBI. Then, bromine MPBI with NBS and AIBN to synthesize brominated polybenzimidazole Br-MPBI. Then, react it with N-[3-(trimethoxysilyl)propyl]ethylenediamine and triethylamine in different molar ratios in DMSO for 3 days, and then pour it into water to precipitate QMPBI-O. x -T y .
[0006] Step 2: Through S N 2. A reaction was conducted to synthesize the [TePeAm]Br2 ionic liquid with two quaternary ammonium groups.
[0007] Step 3: Add QMPBI-O to DMSO x -T y After the polymer is completely dissolved, an ionic liquid is added and mixed until completely dissolved. Then, AIBN is added and, after complete dissolution, the casting solution is poured evenly onto a glass plate. It is placed in an oven at 60°C and left for 4 hours to allow AIBN to initiate double bond polymerization. The temperature is then increased to 90°C until the solvent is completely evaporated. Subsequently, the membrane is subjected to silane crosslinking in 1M H₂SO₄ at 80°C to obtain QMPBI-PO. x -T y Cross-linked membrane. Preferably, the method for preparing a quaternary ammonium type polyionic liquid / quaternary ammonium type polybenzimidazole crosslinked membrane for high-temperature proton exchange membranes is described above, characterized in that the QMPBI-PO x -T y The membrane was cross-linked using a silane cross-linking method to prepare QMPBI-PO. x -T y The membrane exchanges anions for H2PO4 through an acid-base doping reaction. - This forms ion pairs, with the aim of (1) forming a proton transport channel to promote proton transport; and (2) the formed basic sites and PA have strong acid-base interactions, which can effectively reduce PA leakage. The preferred embodiment is the preparation method of a dual quaternary ammonium polyionic liquid / quaternary ammonium polybenzimidazole crosslinked membrane for high-temperature proton exchange membranes, characterized in that the ratio of quaternary ammonium polybenzimidazole to ionic liquid is 7:3. Attached Figure Description
[0008] Figure 1 is QMPBI-O x -T y Flowchart of the preparation process; Figure 2 This is a flowchart of the preparation process of [TePeAm]Br2; Figure 3 It is QMPBI-PO x -T y Flowchart of membrane preparation; Figure 4 It is QMPBI-PO x -T y Phosphoric acid retention rate of the membrane at 160℃ under anhydrous conditions; Figure 5 It is QMPBI-PO x -T y Proton conductivity of the membrane at 100-180℃.
[0009] The technical solution of the present invention will be clearly and completely described below, and detailed implementation methods and specific operation processes will be given. It should be pointed out that researchers in this field can make several improvements and modifications 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.
[0010] Example 1 includes the following steps:
[0011] 72.9 g of polyphosphoric acid was gradually poured into a round-bottom flask at 140 °C. Then, 3.0 g of DAB was added to the reaction mixture and thoroughly mixed. Subsequently, 0.7 g of IPA, 1.8 g of MIPA, and 2.7 g of P₂O₅ were gradually added to the round-bottom flask. When the reactants became viscous, the temperature was raised to 200 °C at a specific rate. To neutralize the polymer, the resulting polymer was poured into deionized water containing sodium bicarbonate. The polymer was then shredded, boiled, and dried to obtain MPBI. The MPBI was brominated by adding 0.3 g of MPBI to a three-necked flask under a nitrogen atmosphere and reflux condenser. Then, 20 mL of DMF was added as a solvent. After the polymer was completely dissolved in the solvent, 117.5 mg of NBS and 10.9 mg of AIBN were added, and the mixture was heated at 65 °C for one day to carry out the bromination reaction. The mixture was washed with water and then dried to obtain a powdered methyl bromide polybenzimidazole (Br-MPBI) with a bromination ratio of 70%. This Br-MPBI was then reacted with N-[3-(trimethoxysilyl)propyl]ethylenediamine and triethylamine in different molar ratios in DMSO for three days. The resulting product was then poured into water to precipitate QMPBI-O. x -T y .
[0012] 0.01 mol of N,N,N',N'-tetramethyl-1,3-propanediamine and 0.022 mol of 5-bromo-1-pentene were added to a 50 mL round-bottom flask. The reaction was carried out at 45 °C for 1 day until the solution turned into a white solid. The solid was poured into acetone and washed repeatedly with acetone to remove unreacted reactants. Then, the mixture was evacuated at room temperature to obtain an ionic liquid with two quaternary ammonium groups—[TePeAm]Br2.
[0013] 0.3g of QMPBI-O x -T y The polymer was dissolved in DMSO. After complete dissolution, an ionic liquid containing two quaternary ammonium groups (30% by mass) was added and stirred until completely dissolved. Then, 1% by mass of AIBN was added and stirred for 30 minutes. The casting solution was poured through a filter cloth onto a clean glass plate until it evenly covered the entire plate. The plate was then placed in a 60°C oven for 4 hours to allow AIBN to initiate double bond polymerization. The temperature was then increased to 90°C until the solvent was completely evaporated. The membrane was then immersed in 1M H₂SO₄ for silane crosslinking. QMPBI-PO was obtained. x -T y membrane.
[0014] QMPBI-PO 10 -T 90 The phosphoric acid retention rate can reach 85.3% at 160℃ under anhydrous conditions.
[0015] QMPBI-PO 10 -T 90 The membrane's proton conductivity reaches 135.5 mS / cm at 180 °C under anhydrous conditions. -1 This indicates that the membrane can be applied to high-temperature proton exchange membranes.
Claims
1. A quaternary ammonium polyionic liquid / quaternary ammonium polybenzimidazole crosslinked membrane for high-temperature proton exchange membranes, prepared by in-situ free radical polymerization of quaternary ammonium polybenzimidazole and ionic liquid. The invention is further described in detail below with reference to embodiments:
1. Gradually pour 72.9 g of polyphosphoric acid into a round-bottom flask at 140 °C. Then, add 3.0 g of DAB to the reaction system and mix thoroughly. Subsequently, gradually add 0.7 g of IPA, 1.8 g of MIPA, and 2.7 g of P2O5 to the round-bottom flask. When the reactants become viscous, raise the temperature to 200 °C at a specific rate. To neutralize the polymer, pour the resulting polymer into deionized water containing sodium bicarbonate. Afterward, cut the polymer into small pieces, boil, and dry to obtain MPBI. The bromination of MPBI was carried out in a nitrogen atmosphere. 0.3 g of MPBI was added to a three-necked flask equipped with a reflux condenser, followed by the addition of 20 mL of DMF as a solvent. After the polymer was completely dissolved in the solvent, 117.5 mg of NBS and 10.9 mg of AIBN were added, and the mixture was heated at 65 °C for one day to carry out the bromination reaction. The mixture was washed with water and then dried to obtain a powdered methyl bromide polybenzimidazole (Br-MPBI) with a bromination ratio of 70%. This Br-MPBI was then reacted with N-[3-(trimethoxysilyl)propyl]ethylenediamine and triethylamine in different molar ratios in DMSO for three days. The mixture was then poured into water to precipitate QMPBI-O. x -T y .
2. Add 0.01 mol of N,N,N',N'-tetramethyl-1,3-propanediamine and 0.022 mol of 5-bromo-1-pentene to a 50 mL round-bottom flask. React at 45 °C for 1 day until the solution turns into a white solid. Pour the solid into acetone and wash repeatedly with acetone to remove unreacted reactants. Then, under vacuum at room temperature, obtain an ionic liquid with two quaternary ammonium groups—[TePeAm]Br2.
3. Add 0.3g of QMPBI-O x -T y The polymer was dissolved in DMSO. After complete dissolution, an ionic liquid containing two quaternary ammonium groups (30% by mass) was added and stirred until completely dissolved. Then, 1% by mass of AIBN was added and stirred for 30 minutes. The casting solution was poured through a filter cloth onto a clean glass plate until it evenly covered the entire plate. The plate was then placed in a 60°C oven for 4 hours to allow AIBN to initiate double bond polymerization. The temperature was then increased to 90°C until the solvent was completely evaporated. The membrane was then immersed in 1M H₂SO₄ for silane crosslinking. QMPBI-PO was obtained. x -T y membrane.