CN109390601B

CN109390601B - Preparation method of ion exchange membrane

Info

Publication number: CN109390601B
Application number: CN201710672219.XA
Authority: CN
Inventors: 徐鹤英; 张华民; 邹毅; 张涛; 高新亮; 张志英
Original assignee: Dalian Rongke Power Co Ltd
Current assignee: Dalian Rongke Power Co Ltd
Priority date: 2017-08-08
Filing date: 2017-08-08
Publication date: 2021-11-26
Anticipated expiration: 2037-08-08
Also published as: CN109390601A

Abstract

The invention relates to a preparation method of an ion exchange membrane, which specifically comprises the following steps of 1, preparing a membrane forming solution; 2. forming a diaphragm; 3. modification treatment; the step 3 comprises the following steps: 1) preparing a modified solution: the modified solution is a sodium sulfate solution, a potassium sulfate solution or a mixture of the sodium sulfate solution and the potassium sulfate solution; 2) soaking the diaphragm formed in the step 2 in a modified solution for 30-90 minutes; 3) drying the soaked diaphragm in a constant-temperature drying box; 4) and taking out the dried diaphragm and cooling to room temperature to obtain the final ion exchange membrane. The preparation method of the ion exchange membrane provided by the invention has the advantages of simple preparation process, easiness in realization, good safety and low cost, and is suitable for batch production. The mechanical property of the ion exchange membrane prepared by the method is greatly improved, the coulomb efficiency and the energy efficiency of the assembled battery can be improved by about 3 percent, and the stability of the battery performance is good.

Description

Preparation method of ion exchange membrane

Technical Field

The invention relates to a preparation method of an ion exchange membrane, belonging to the field of high polymer materials.

Background

Electric energy is difficult to store and indispensable, and the production of the electric energy at any time meets the power utilization requirement, so people always find an economical and feasible energy storage technology to solve the contradiction between supply and demand and unhook the production and the demand of the electric energy. In addition, the electric energy storage has important effects on the aspects of electric energy management, power grid auxiliary service, voltage control, renewable energy utilization, large uninterrupted power supply and the like, and if the electric energy storage is combined with large thermal power generation, the peak capacity of a power station can be reduced, the power generation cost can be reduced, and the pollution can be reduced. If the device is combined with renewable energy sources such as wind power, tidal power and the like for power generation, continuous and stable supply of electric energy can be realized, and the requirements of users are met. Since the flow battery has the characteristics of power and capacity separation, is easy to design and convenient to operate, and is gradually one of the most promising large and medium-scale power storage options. Among them, flow batteries are preferred.

At present, the flow battery galvanic pile mostly adopts a filter press structure and mainly comprises a bipolar plate, a positive electrode, a negative electrode, an electrode frame, an ion exchange membrane (also called a diaphragm), an end plate, a sealing material and a fastening piece. Wherein, an electrode frame is arranged between the two bipolar plates, the electrode frame is of a hollow structure, positive and negative electrodes are respectively arranged in the electrode frame, and a diaphragm is arranged between the positive and negative electrodes. The positive electrolyte and the negative electrolyte used in the flow battery are respectively stored in a positive electrolyte storage tank and a negative electrolyte storage tank.

The ion exchange membrane is very important for the flow battery, is one of the most important components of a flow battery system, and is the key for determining the performance of the whole flow battery. The device separates the positive electrolyte from the negative electrolyte, and allows charge carriers to freely pass through so as to ensure the charge balance of the positive electrolyte and the negative electrolyte. The existing ion exchange membrane still has the defects of low stability, high swelling degree, high production cost, complex process, poor mechanical property and the like.

The current methods are as follows: by utilizing the treatment solution or the electrolyte, the ion exchange membrane is subjected to pretreatment before being assembled in the galvanic pile so as to ensure that the volume of the ion exchange membrane is not changed after the ion exchange membrane is assembled and the electrolyte is introduced, and prevent the sealing property of the galvanic pile from being damaged due to the form change of the ion exchange membrane. The following problems still remain: the treatment time of the ion exchange membrane is long, the toxicity of the treatment solution is strong, the safety is poor, the price of the treatment solution is high, and the cost is increased; the battery performance of the ion exchange membrane after assembly treatment is low, and the development of the flow battery is severely restricted.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a preparation method of an ion exchange membrane, the mechanical property of the ion exchange membrane prepared by the method is greatly improved, the coulomb efficiency and the energy efficiency of a battery after assembly can be improved by about 3%, and meanwhile, the production cost of the membrane can be greatly reduced.

A preparation method of an ion exchange membrane specifically comprises the following steps:

step 1: preparing a film forming solution;

step 2: forming a diaphragm;

and step 3: modification treatment:

1) preparing a modified solution: the modified solution is a sodium sulfate solution, a potassium sulfate solution or a mixture of the sodium sulfate solution and the potassium sulfate solution, wherein the mass percent of the sodium sulfate is 1-8%, and the mass percent of the potassium sulfate is 1-5%;

2) soaking the diaphragm obtained in the step 2 in a modified solution for 30-90 minutes;

3) drying the soaked diaphragm in a constant-temperature drying box, wherein the drying temperature is controlled to be 80-120 ℃, and the drying time is 60-120 minutes;

4) and taking out the dried diaphragm and cooling to room temperature to obtain the final ion exchange membrane.

Further, the step 1 is as follows: preparing a film-forming solution by using N, N-dimethylformamide as a solvent and perfluorosulfonic acid resin or sulfonated polyether ether ketone as a solute, wherein the mass percent of the perfluorosulfonic acid resin is 1-20%, and the mass percent of the sulfonated polyether ether ketone is 1-20%; the mass percentage of the perfluorosulfonic acid resin is more preferably 10%; the mass percentage of the sulfonated polyether ether ketone is more preferably 12%.

Further, the separator described in step 2 is formed into: and (3) casting the solution obtained in the step (1) into a film by using a casting method.

Further, the modification solution in the step 1) is a sodium sulfate solution, and the mass percentage is 4-6%, and more preferably 5%.

Further, the modified solution in the step 1) is a potassium sulfate solution, and the mass percentage is 3%.

Further, the modified solution in the step 1) is a mixed solution of sodium sulfate and potassium sulfate, wherein the mass percent of the sodium sulfate is 3%, and the mass percent of the potassium sulfate is 2%.

Further, the soaking time in the step 2) is 60-90 minutes, and further preferably 60 or 90 minutes.

Further, the drying temperature in the step 3) is controlled to be 80-100 ℃, and further preferably 80 or 100 ℃; the drying time is 60-90 minutes; further preferably 60 or 90 minutes.

The first two steps of the preparation method of the ion exchange membrane can also be conventional film forming steps of other types of ion exchange membranes, such as sulfonated polyvinylidene fluoride ion exchange membranes, sulfonated polysulfone ion exchange membranes, sulfonated polyether sulfone ion exchange membranes, sulfonated polyphenylene ether ion exchange membranes, sulfonated polybenzimidazole ion exchange membranes, sulfonated polyimide ion exchange membranes and the like.

The casting method is a process of uniformly coating a polymer solution having a certain viscosity on a flat support material and then drying it to form a film. The advantages of the fluid court method are that (1) the process range is wide; (2) isotropy of film properties; (3) mass production of the film is easy to realize; (4) a plurality of substances can be compounded to prepare the composite material with specific functions. Thus, isotropic ion exchange membranes can be prepared in a wide range of processes using the fluidly coupled process.

The invention has the beneficial effects that: the preparation method of the ion exchange membrane provided by the invention has the advantages of simple preparation process, easiness in realization, good safety and low cost, and is suitable for batch production. The mechanical property of the ion exchange membrane prepared by the method is greatly improved, the coulomb efficiency and the energy efficiency of the assembled battery can be improved by about 3 percent, and the stability of the battery performance is good.

Detailed Description

The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.

The test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Example 1

A method of preparing an ion exchange membrane comprising:

1. preparing a film forming solution: dissolving perfluorinated sulfonic acid resin in N, N-dimethylformamide, wherein the mass percent of the perfluorinated sulfonic acid resin is 10%;

2. forming a diaphragm: casting the perfluorinated sulfonic acid resin solution into a film by using a casting method, wherein the thickness of the film is 50 mu m;

3. modification treatment: the method comprises the following steps:

1) preparing a modified solution: preparing a sodium sulfate solution with the mass percent of 1%;

2) soaking the diaphragm in the modified solution for 60 minutes;

3) drying the soaked diaphragm in a constant-temperature drying box at 80 ℃ for 60 minutes;

Comparative example 1

A method of preparing an ion exchange membrane comprising:

1. preparing a film forming solution: dissolving perfluorinated sulfonic acid resin in N, N-dimethylformamide, wherein the mass percent of the resin is 10%;

2. forming a diaphragm: the perfluorosulfonic acid resin solution was cast into a film having a thickness of 50 μm by a casting method.

Comparative example 2

A method of preparing an ion exchange membrane comprising:

1. preparing a film forming solution: dissolving sulfonated polyether ether ketone resin in N, N-dimethylformamide, wherein the mass percent of the resin is 12%;

2. forming a diaphragm: the sulfonated polyether ether ketone resin solution is cast into a film by a casting method, and the film thickness is 50 mu m.

Examples 2 to 48, the preparation process was carried out in the same manner as in example 1 except that the following preparation parameters were different.

See the following table for details:

as can be seen from the table, the coulomb efficiency and the energy efficiency of the assembled battery of the ion exchange membrane prepared by the method are improved by about 3 percent.

Claims

1. A preparation method of an ion exchange membrane, which is used for a flow battery, comprises the following steps:

step 1: preparing a film forming solution;

step 2: forming a diaphragm;

it is characterized in that the method also comprises the following steps: modification treatment:

1) preparing a modified solution: the modified solution is a sodium sulfate solution, a potassium sulfate solution or a mixture of the sodium sulfate solution and the potassium sulfate solution, wherein the mass fraction of the sodium sulfate solution is 1-8%, and the mass fraction of the potassium sulfate solution is 1-5%;

3) drying the soaked diaphragm in a constant-temperature drying box, wherein the drying temperature is controlled to be 80-120 ℃; the drying time is 60-120 minutes;

2. The method for preparing an ion exchange membrane according to claim 1, wherein the step 1 is: the method comprises the steps of preparing a film forming solution by using N, N-dimethylformamide as a solvent and perfluorosulfonic acid resin or sulfonated polyether ether ketone as a solute, wherein the mass fraction of the film forming solution formed by the perfluorosulfonic acid resin is 1-20%, and the mass fraction of the film forming solution formed by the sulfonated polyether ether ketone is 1-20%.

3. The method for preparing an ion exchange membrane according to claim 2, wherein the mass fraction of the membrane solution formed by the perfluorosulfonic acid resin in the step 1 is 10%; the mass fraction of the membrane solution formed by the sulfonated polyether ether ketone is 12 percent.

4. The preparation method of the ion exchange membrane according to claim 1, wherein the modification solution in the step 1) is a sodium sulfate solution, and the mass fraction of the sodium sulfate solution is 4-6%.

5. The method for preparing the ion exchange membrane according to claim 1, wherein the modified solution in the step 1) is potassium sulfate solution, and the mass fraction of the modified solution is 3%.

6. The method for preparing an ion exchange membrane according to claim 1, wherein the modified solution in the step 1) is a mixed solution of sodium sulfate and potassium sulfate, the mass fraction of the sodium sulfate solution is 3%, and the mass fraction of the potassium sulfate solution is 2%.

7. The method for preparing an ion-exchange membrane according to claim 4, wherein the mass fraction of the sodium sulfate solution is 5%.

8. The method for preparing an ion exchange membrane according to any one of claims 4 to 7, wherein the soaking time in the step 2) is 60 to 90 minutes.

9. The method for preparing an ion-exchange membrane according to any one of claims 4 to 7, wherein the drying temperature in the step 3) is controlled to be 80 to 100 ℃ and the drying time is 60 to 90 minutes.

10. The method of preparing an ion exchange membrane according to claim 8, wherein the soaking time is 60 or 90 minutes.