A kind of porous polymer ion exchange membrane based on polybenzimidazole and its preparation method and application by sol-gel method

Abstract

The invention discloses a polybenzimidazole-based porous polymer ion exchange membrane and its preparation method and application by a sol-gel method. The porous membrane is prepared by a sol-gel method, and polyphosphoric acid is A solution of polybenzimidazole was cast into a film, and a transition from a solution state to a gel state was observed during the hydrolysis of the solution from polyphosphoric acid to phosphoric acid. After being solidified into a film by dipping and pulling method, phosphoric acid remains in the gel structure of the film, and a sponge-like dense porous structure is formed after phosphoric acid is washed away. After the prepared porous membrane is doped with alkali, the transfer of ion exchange can be realized without the need of ion exchange groups. The sol-gel method of the invention has the characteristics of low cost, simple process, easy large-area film formation, easy control of stoichiometric ratio, high product purity and good uniformity. The porous film produced by the invention is applied to the alkaline water electrolyzer after alkali doping, exhibits high ion conductivity and stable mechanical properties, and has a very good application prospect in the alkaline water electrolyzer.

Description

technical field

[0001] The invention belongs to the technical field of alkaline water electrolyzer, relates to a porous polymer ion exchange membrane material, in particular to a polybenzimidazole-based porous polymer ion exchange membrane and its preparation method and application by sol-gel method . Background technique

[0002] At present, electrochemical energy storage technology (that is, the storage of renewable energy surplus electricity in the form of hydrogen by splitting water electrochemically) has received more and more attention (IEEE, 2012, 100, 410). Proton exchange membrane (PEM) systems based on perfluorosulfonic acid membranes can produce high-purity hydrogen at high current densities, but are limited by electrode materials and catalysts in acidic environments, which hinders their large-scale application, making People began to turn to the traditional alkaline water electrolyzer technology. Under alkaline conditions, the relatively easy oxidation-reduction...

Examples

Embodiment 1

[0039] A kind of method adopting sol-gel method to prepare the porous polymer ion-exchange membrane based on polybenzimidazole, comprises the following steps:

[0040] 1. Preparation of stable solution.

[0041] Isophthalic acid (6.230g) and biphenyl tetramine (8.037g) are dissolved in the PPA of 300g, and the pH of adjusting solution is 1, obtains stable, transparent solution, is fully stirred under 110 ℃ at temperature, then in Polymerization at 250°C for 24h;

[0042] 2. Preparation of porous polybenzimidazole polymer electrolyte separator by sol-gel method. This step is as follows: slowly immerse the cleaned 20*20cm glass plate in the solution with a temperature of 250°C after polymerization, let it stand for 10 minutes, and pull the glass plate vertically upward at a speed of 0.05m / s. Immediately heat treatment in a steam atmosphere with a humidity of 50% for 24 hours to solidify and form a film, and repeat 5 times to obtain a film with a certain thickness. Soak the me...

Embodiment 2

[0049] A kind of method adopting sol-gel method to prepare the porous polymer ion-exchange membrane based on polybenzimidazole, comprises the following steps:

[0050] 1. The preparation steps of the stable solution are the same as in Example 1.

[0051] 2. Preparation of porous polybenzimidazole polymer electrolyte separator by sol-gel method. This step is as follows: slowly immerse the cleaned 20*20cm glass plate in the solution with a temperature of 250°C after polymerization, let it stand for 10 minutes, and pull the glass plate vertically upward at a speed of 0.05m / s. Immediately heat treatment in a steam atmosphere with a humidity of 60% for 24 hours to solidify and form a film, and repeat 5 times to obtain a film with a certain thickness. Soak the membrane in 1M ammonium hydroxide at 80°C for 12 hours to fully wash away the phosphoric acid in the membrane, then place the membrane in deionized water at 50°C for 12 hours, wash away the residual impurities, and dry it in ...

Embodiment 3

[0054] A kind of method adopting sol-gel method to prepare the porous polymer ion-exchange membrane based on polybenzimidazole, comprises the following steps:

[0055] 1. The preparation steps of the stable solution are consistent with Example 1.

[0056] 2. Preparation of porous polybenzimidazole polymer electrolyte separator by sol-gel method. This step is as follows: slowly immerse the cleaned 20*20cm glass plate in the solution with a temperature of 250°C after polymerization, let it stand for 10 minutes, and pull the glass plate vertically upward at a speed of 0.05m / s. Immediately heat treatment in a steam atmosphere with a humidity of 70% for 24 hours to solidify and form a film, and repeat 5 times to obtain a film with a certain thickness. Soak the membrane in 1M ammonium hydroxide at 80°C for 12 hours to fully wash away the phosphoric acid in the membrane, then place the membrane in deionized water at 50°C for 12 hours, wash away the residual impurities, and dry it in...

technical field

[0001] The invention belongs to the technical field of alkaline water electrolyzer, relates to a porous polymer ion exchange membrane material, in particular to a polybenzimidazole-based porous polymer ion exchange membrane and its preparation method and application by sol-gel method . Background technique

[0002] At present, electrochemical energy storage technology (that is, the storage of renewable energy surplus electricity in the form of hydrogen by splitting water electrochemically) has received more and more attention (IEEE, 2012, 100, 410). Proton exchange membrane (PEM) systems based on perfluorosulfonic acid membranes can produce high-purity hydrogen at high current densities, but are limited by electrode materials and catalysts in acidic environments, which hinders their large-scale application, making People began to turn to the traditional alkaline water electrolyzer technology. Under alkaline conditions, the relatively easy oxidation-reduction...

Examples

Embodiment 1

[0039] A kind of method adopting sol-gel method to prepare the porous polymer ion-exchange membrane based on polybenzimidazole, comprises the following steps:

[0040] 1. Preparation of stable solution.

[0041] Isophthalic acid (6.230g) and biphenyl tetramine (8.037g) are dissolved in the PPA of 300g, and the pH of adjusting solution is 1, obtains stable, transparent solution, is fully stirred under 110 ℃ at temperature, then in Polymerization at 250°C for 24h;

[0042] 2. Preparation of porous polybenzimidazole polymer electrolyte separator by sol-gel method. This step is as follows: slowly immerse the cleaned 20*20cm glass plate in the solution with a temperature of 250°C after polymerization, let it stand for 10 minutes, and pull the glass plate vertically upward at a speed of 0.05m / s. Immediately heat treatment in a steam atmosphere with a humidity of 50% for 24 hours to solidify and form a film, and repeat 5 times to obtain a film with a certain thickness. Soak the me...

Embodiment 2

[0049] A kind of method adopting sol-gel method to prepare the porous polymer ion-exchange membrane based on polybenzimidazole, comprises the following steps:

[0050] 1. The preparation steps of the stable solution are the same as in Example 1.

[0051] 2. Preparation of porous polybenzimidazole polymer electrolyte separator by sol-gel method. This step is as follows: slowly immerse the cleaned 20*20cm glass plate in the solution with a temperature of 250°C after polymerization, let it stand for 10 minutes, and pull the glass plate vertically upward at a speed of 0.05m / s. Immediately heat treatment in a steam atmosphere with a humidity of 60% for 24 hours to solidify and form a film, and repeat 5 times to obtain a film with a certain thickness. Soak the membrane in 1M ammonium hydroxide at 80°C for 12 hours to fully wash away the phosphoric acid in the membrane, then place the membrane in deionized water at 50°C for 12 hours, wash away the residual impurities, and dry it in ...

Embodiment 3

[0054] A kind of method adopting sol-gel method to prepare the porous polymer ion-exchange membrane based on polybenzimidazole, comprises the following steps:

[0055] 1. The preparation steps of the stable solution are consistent with Example 1.

[0056] 2. Preparation of porous polybenzimidazole polymer electrolyte separator by sol-gel method. This step is as follows: slowly immerse the cleaned 20*20cm glass plate in the solution with a temperature of 250°C after polymerization, let it stand for 10 minutes, and pull the glass plate vertically upward at a speed of 0.05m / s. Immediately heat treatment in a steam atmosphere with a humidity of 70% for 24 hours to solidify and form a film, and repeat 5 times to obtain a film with a certain thickness. Soak the membrane in 1M ammonium hydroxide at 80°C for 12 hours to fully wash away the phosphoric acid in the membrane, then place the membrane in deionized water at 50°C for 12 hours, wash away the residual impurities, and dry it in...

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