CN110197918A - A kind of perfluorinated sulfonic acid composite membrane used for all-vanadium redox flow battery and its preparation method and application - Google Patents

Abstract

The invention discloses a perfluorosulfonic acid composite membrane for an all-vanadium redox flow battery and its preparation method and application. The perfluorosulfonic acid ion exchange membrane and ammoniated polysulfone are used as materials and prepared by a blending method. The perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery is described, and the method effectively improves the vanadium ion selectivity of the composite membrane, so that the composite membrane has better charge and discharge performance in the all-vanadium redox flow battery. The rigid structure of the ammoniated polysulfone is beneficial to increase the mechanical properties of the composite membrane, which can effectively limit the expansion of the composite membrane. The preparation method of the invention is simple, effectively utilizes the discarded perfluorosulfonic acid proton exchange membrane, not only realizes waste utilization, but also saves cost. The prepared composite membrane takes into account high ion conductivity, low vanadium ion permeability, swelling and water absorption, and is suitable for all-vanadium redox flow batteries.

Description

A perfluorosulfonic acid composite membrane for all-vanadium redox flow battery and its preparation method and application

technical field

The invention belongs to the technical field of all-vanadium redox flow batteries, and in particular relates to a perfluorosulfonic acid composite membrane for all-vanadium redox flow batteries and its preparation method and application.

Background technique

Liquid flow battery is a new type of electrochemical energy storage technology, which has the advantages of high efficiency, modular design, safety and environmental protection, simple maintenance, and low operating cost. Smart grid and other fields have shown outstanding application prospects. Vanadium flow battery (Vanadium flow battery, VFB) is currently the most promising liquid flow battery due to its high charge and discharge efficiency, environmental friendliness, flexible design, high safety, low self-discharge, and long life. flow battery.

The battery separator is one of the key materials of the all-vanadium redox flow battery. On the one hand, the battery separator separates the positive and negative electrolytes to avoid cross-contamination of positive and negative active ions and self-discharge; on the other hand, it allows conductive ions such as protons to Through, the circuit inside the battery is formed. The battery separator of VFB should have the following characteristics: high ionic conductivity, so that the battery has a high voltage efficiency, so as to reduce the polarization of the battery; high vanadium ion selectivity, so that the battery has a high coulombic efficiency, reduce the battery Self-discharge; has good mechanical properties, chemical corrosion resistance, electrochemical oxidation resistance, and ensures a long service life.

At present, the diaphragm material used in commercialized vanadium batteries at home and abroad is still mainly Nafion film developed by DuPont. In flow batteries, although Nafion membranes are relatively expensive and have poor ion selectivity, they are still unmatched by many commercial membranes in terms of ion conductivity, mechanical properties, chemical properties and service life. However, the poor selectivity of Nafion membranes has always been a difficult problem for people. The traditional modification is often to reduce the nanochannels inside the membrane by filling or doping with nanoparticles. Although this method can improve the selectivity of the membrane, it is not The conductivity of the membrane to hydrogen ions will also be greatly affected, so it cannot effectively solve the problem. However, if the agglomerated sulfonic acid functional groups can be dispersed with basic groups, the radius of the clusters can be reduced, the selectivity of the membrane can be increased, and the influence on the conduction of hydrogen ions can also be weakened.

Contents of the invention

In order to improve the deficiencies in the prior art, the present invention provides a perfluorosulfonic acid composite membrane for an all-vanadium redox flow battery and its preparation method and application. A perfluorosulfonic acid composite membrane for all-vanadium redox flow batteries with less consumables, good ion selectivity and excellent performance was prepared by blending polysulfone. The method rationally utilizes the discarded perfluorosulfonic acid ion exchange membrane, effectively reduces the production cost, and improves the vanadium resistance performance of the perfluorosulfonic acid membrane composite membrane.

The technical scheme that the present invention adopts is as follows:

A method for preparing a perfluorosulfonic acid composite membrane for an all-vanadium redox flow battery, comprising the steps of:

(1) prepare the mixed solution of perfluorosulfonic acid proton exchange membrane and polysulfone resin after ammoniation treatment;

(2) The mixed solution in step (1) is contacted with the substrate, and heat-treated twice to prepare the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery.

Wherein, step (1) may include the following steps: dissolving the perfluorosulfonic acid proton exchange membrane and the ammoniated polysulfone resin in an organic solvent respectively to prepare a perfluorosulfonic acid solution and an ammoniated polysulfone solution, and The two are mixed to prepare a mixed solution.

According to an embodiment of the present invention, in step (1), the perfluorosulfonic acid proton exchange membrane is selected from pretreated perfluorosulfonic acid proton exchange membranes, or is selected from discarded perfluorosulfonic acid proton exchange membranes, Alternatively, it can be selected from pretreated waste perfluorosulfonic acid proton exchange membranes.

According to an embodiment of the present invention, in step (1), the organic solvent is N,N-dimethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl at least one of sulfoxide or N-methylpyrrolidone.

According to an embodiment of the present invention, in step (1), the weight concentration of the perfluorosulfonic acid proton exchange membrane in the perfluorosulfonic acid solution is 2 to 10 wt%, and the ammoniated polysulfone solution in the ammoniated polysulfone solution is The weight concentration of polysulfone resin is 2-15wt%.

According to an embodiment of the present invention, in step (1), the weight ratio of the perfluorosulfonic acid proton exchange membrane and the ammonated polysulfone resin in the mixed solution is (60-99.999):(0.001-40).

According to an embodiment of the present invention, step (1) includes the following steps: dissolving the pretreated perfluorosulfonic acid proton exchange membrane and the ammoniated polysulfone resin in an organic solvent to prepare a perfluorosulfonic acid solution Mix the two with ammoniated polysulfone solution, stir them by magnetic force for 1-3 hours, ultrasonically disperse for 20-40 minutes, and then stand at 40-80° C. for 4-7 hours to prepare a mixed solution.

According to an embodiment of the present invention, in step (2), the mixed solution can be mixed with the substrate by methods including but not limited to casting, dipping, screen printing, inkjet printing, roll coating, spray painting, spray coating, spin coating and/or vapor deposition. material contact.

According to an embodiment of the present invention, in step (2), the substrate is selected from glass, single crystal silicon, polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polyethylene naphthalate At least one of glycol ester (PEN), polyimide (PI) and the like.

According to an embodiment of the present invention, the step (2) includes the following steps: apply the mixed solution of the step (1) to the surface of the substrate, perform the first heat treatment at 40-80° C., and cool down at 100 The second heat treatment is carried out under a vacuum condition of ~170° C. to prepare the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery.

According to an embodiment of the present invention, the step (2) includes the following steps: apply the mixed solution of the step (1) to the surface of the substrate, perform the first heat treatment in an oven at 40-80° C. for 8-14 hours, and cool down Afterwards, transfer to a vacuum oven, and perform a second heat treatment in a vacuum oven at 100-170° C. for 3-6 hours to prepare the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery.

According to an embodiment of the present invention, the vacuum degree of the vacuum oven is 0.01-0.1 MPa, such as 0.08 MPa.

The present invention also provides a perfluorosulfonic acid composite membrane for an all-vanadium redox flow battery, and the composite membrane is prepared by the above method.

Wherein, the thickness of the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery is 50-150 μm.

The invention also provides the use of a perfluorosulfonic acid composite membrane, which is used in an all-vanadium redox flow battery.

The present invention also provides an all-vanadium redox flow battery, which comprises the above-mentioned perfluorosulfonic acid composite membrane.

Beneficial result of the present invention is:

1. The present invention takes perfluorosulfonic acid ion-exchange membrane (preferably discarded perfluorosulfonic acid ion-exchange membrane) and ammoniated polysulfone as raw materials, and prepares the described all-vanadium redox flow battery by blending method. A perfluorosulfonic acid composite membrane, the method effectively improves the selectivity of the composite membrane to vanadium ions, so that the composite membrane has better charge and discharge performance in an all-vanadium redox flow battery.

2. The rigid structure of ammoniated polysulfone in the composite membrane of the present invention is beneficial to increase the mechanical properties of the composite membrane, which can effectively limit the expansion of the composite membrane.

3. In the process of preparing the composite membrane of the present invention, the regulation of the composite membrane can be realized by controlling the mixing ratio of the ammoniated polysulfone solution and the perfluorosulfonic acid solution, and then the performance of the battery using the composite membrane can be improved. Controllable adjustment.

4. The preparation method of the present invention is simple, effectively utilizes the discarded perfluorosulfonic acid proton exchange membrane, realizes waste utilization, and saves cost. The prepared composite membrane takes into account high ion conductivity, low vanadium ion permeability, swelling and water absorption, and is suitable for all-vanadium redox flow batteries.

Description of drawings

Fig. 1 is the SEM surface topography diagram of the composite film prepared in Example 1 and Comparative Example 1.

Figure 2 is the charge and discharge curves of the composite membranes prepared in Example 1 and Comparative Example 1 in an all-vanadium redox flow battery.

Detailed ways

[Preparation method of perfluorosulfonic acid composite membrane]

As mentioned above, the present invention provides a method for preparing a perfluorosulfonic acid composite membrane for an all-vanadium redox flow battery, comprising the following steps:

(1) prepare the mixed solution of perfluorosulfonic acid proton exchange membrane and polysulfone resin after ammoniation treatment;

(2) The mixed solution in step (1) is contacted with the substrate, and heat-treated twice to prepare the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery.

In one solution of the present invention, in step (1), the preparation method of the mixed solution is not particularly limited, it can be a method known to those skilled in the art, as an example, it can be the The sulfonic acid proton exchange membrane and the ammoniated polysulfone resin are respectively dissolved in an organic solvent to prepare a perfluorosulfonic acid solution and an ammoniated polysulfone solution, and the two are mixed to prepare a mixed solution; The fluorosulfonic acid proton exchange membrane is dissolved in an organic solvent to obtain a perfluorosulfonic acid solution, and then the ammoniated polysulfone resin is dissolved in it; or the ammoniated polysulfone resin is dissolved in an organic solvent , to obtain an ammoniated polysulfone solution, and then dissolve the perfluorosulfonic acid proton exchange membrane in it.

In one solution of the present invention, in step (1), the perfluorosulfonic acid proton exchange membrane is not particularly limited, it can be selected from any perfluorosulfonic acid proton exchange membrane known in the prior art , such as selected from pretreated perfluorosulfonic acid proton exchange membranes, or from discarded perfluorosulfonic acid proton exchange membranes, or from pretreated discarded perfluorosulfonic acid proton exchange membranes; Those skilled in the art can understand that the selection of the perfluorosulfonic acid proton exchange membrane can meet the requirement that it can be dissolved in an organic solvent and mixed with the ammoniated polysulfone solution to prepare the perfluorosulfonic acid for the all-vanadium redox flow battery. composite film.

In one solution of the present invention, in step (1), the pretreatment can be any pretreatment for discarded perfluorosulfonic acid proton exchange membranes known in the prior art, and through the pretreatment Treatment can remove high-valent vanadium ions and other impurities in the spent perfluorosulfonic acid proton exchange membrane. As an example, the recovered waste perfluorosulfonic acid ion exchange membrane is cut into pieces of about 0.25 cm ² , immersed in hydrogen peroxide solution, stirred at 40-100°C for 10-24 hours, and then washed with deionized water; After cleaning, immerse in a sulfuric acid solution, stir at 40-100° C. for 10-24 hours, and wash again with deionized water to obtain a pretreated perfluorosulfonic acid proton exchange membrane. The purpose of the shredding is to better process the discarded perfluorosulfonic acid proton exchange membrane and remove other impurities such as high-valent vanadium ions therein. Those skilled in the art can understand that the step of shredding is not necessary, and similarly, the degree of shredding is not limited to about 0.25 cm ² .

In one solution of the present invention, in step (1), the concentration of the hydrogen peroxide solution and the sulfuric acid solution is not particularly limited, which can realize the removal of high-valent vanadium ions in the discarded perfluorosulfonic acid proton exchange membrane and the The protonation treatment of the perfluorosulfonic acid proton exchange membrane is sufficient. Preferably, the weight concentration of the hydrogen peroxide solution is 1-15 wt%, and the concentration of the sulfuric acid solution is 0.2-3M (mol/L).

In one solution of the present invention, in step (1), the polysulfone resin is selected from polysulfone resins with any molecular weight and degree of polymerization known in the prior art, and the ammoniation treatment is also a prior art Any method in which polysulfone resin can be ammonated; the ammoniated treatment is by introducing a nitro group or a branched chain containing a nitro group on the benzene ring of the polysulfone main chain, and converting the nitro group into Amino groups, that is, to realize the ammoniated treatment of polysulfone resin. The purpose of the ammoniation treatment is to make the polysulfone resin have better hydrophilicity and increase the compatibility with the perfluorosulfonic acid proton exchange membrane. Not only that, the polysulfone resin after the ammoniation treatment has The rigid structure can increase the mechanical properties of the prepared composite membrane, thereby effectively limiting the expansion of the composite membrane and greatly increasing its service life.

In one solution of the present invention, in step (1), the organic solvent is N,N-dimethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, di At least one of methyl sulfoxide or N-methylpyrrolidone.

In one solution of the present invention, in step (1), the weight ratio of the perfluorosulfonic acid proton exchange membrane and the ammoniated polysulfone resin in the mixed solution is (60-99.999): (0.001-40) .

In one solution of the present invention, step (1) specifically includes the following steps: respectively dissolving the pretreated perfluorosulfonic acid proton exchange membrane and the ammoniated polysulfone resin in an organic solvent to prepare perfluorosulfonic acid The acid solution and the ammoniated polysulfone solution are mixed, stirred by magnetic force for 1-3 hours, ultrasonically dispersed for 20-40 minutes, and then left to stand at a temperature of 40-80° C. for 4-7 hours to prepare a mixed solution.

In one solution of the present invention, the weight concentration of the perfluorosulfonic acid proton exchange membrane in the perfluorosulfonic acid solution is 2-10 wt%. The weight concentration of the ammoniated polysulfone resin in the ammoniated polysulfone solution is 2-15 wt%.

In one solution of the present invention, in step (1), the organic solvent that dissolves the perfluorosulfonic acid proton exchange membrane and the organic solvent that dissolves the polysulfone resin after ammoniation treatment can be the same organic solvent, and can also be the organic solvent that has relatively Two organic solvents with good compatibility.

In one solution of the present invention, in step (2), the contacting method is not specifically limited, as long as the purpose of preparing the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery can be achieved. Those skilled in the art can understand that the mixed solution can be contacted with the substrate by methods including but not limited to casting, dipping, screen printing, inkjet printing, roller coating, spray painting, spray coating, spin coating and/or vapor deposition. Exemplarily, the mixed solution is placed on the surface of the substrate for spin coating, or the substrate is immersed in the mixed solution for dip coating, etc., or the mixed solution is cast onto the surface of the substrate.

In one solution of the present invention, in step (2), the selection of the substrate is not specifically limited, and it can be any commonly used substrate for preparing membrane materials that does not react with the composite membrane, such as Glass, monocrystalline silicon, polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), etc.; similarly Those skilled in the art will understand that the shape of the substrate is not specifically limited, and it can be selected according to requirements, for example, it can be a flat substrate (such as a glass sheet) that is easy to form a film. , single crystal silicon wafer, etc.), it can also be a mold with a specific shape (such as a cuboid or cylinder).

In one solution of the present invention, in step (2), the thickness of the mixed solution on the surface of the substrate is not specifically limited, which can ensure that the prepared perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery can realize The purpose of using the composite membrane is to separate the positive and negative electrolytes, avoid cross-contamination of active ions in the positive and negative electrodes, and self-discharge; and allow conductive ions such as protons to pass through, thereby forming an internal circuit of the battery. As an example, the thickness of the mixed solution applied to the surface of the substrate should ensure that the thickness of the composite film obtained after two heat treatments is 50-150 μm.

In one solution of the present invention, the step (2) specifically includes the following steps: apply the mixed solution of the step (1) to the surface of the substrate, perform the first heat treatment at 40-80°C, and after cooling down, The second heat treatment is carried out under a vacuum condition of 100-170° C. to prepare the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery.

In one solution of the present invention, the step (2) specifically includes the following steps: apply the mixed solution of the step (1) to the surface of the substrate, and perform the first heat treatment in an oven at 40-80°C for 8-14 hours , after cooling down, transfer to a vacuum oven, and perform a second heat treatment in a vacuum oven at 100-170° C. for 3-6 hours to prepare the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery.

In one solution of the present invention, the vacuum degree of the vacuum oven is 0.01-0.1 MPa, such as 0.08 MPa.

[Perfluorosulfonic acid composite membrane]

As mentioned above, the present invention provides a perfluorosulfonic acid composite membrane for an all-vanadium redox flow battery, and the composite membrane is prepared by the above method.

In one solution of the present invention, the thickness of the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery is 50-150 μm.

[Use of perfluorosulfonic acid composite membrane]

As mentioned above, the present invention provides the use of a perfluorosulfonic acid composite membrane, which is used in an all-vanadium redox flow battery.

[All vanadium redox flow battery]

As mentioned above, the present invention also provides an all-vanadium redox flow battery, which comprises the above-mentioned perfluorosulfonic acid composite membrane.

In one solution of the present invention, the charging voltage of the all-vanadium redox flow battery is lower than 1.45V, and the discharging voltage is higher than 1.35V.

In one solution of the present invention, the coulombic efficiency of the all-vanadium redox flow battery is above 95%, the voltage efficiency is above 86%, and the energy efficiency is above 83%.

The voltage efficiency refers to the ratio of the average voltage of the discharge voltage to the average voltage of the charge voltage.

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the protection scope of the present invention. In addition, it should be understood that after reading the disclosure of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope of protection defined by the present invention.

The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents and materials used in the following examples can be obtained from commercial sources unless otherwise specified.

Example 1

Dissolve 5g of the pretreated waste perfluorosulfonic acid proton exchange membrane (discarded Nafion membrane) and 5g of ammoniated polysulfone in 45mL of N-methylpyrrolidone solvent respectively to prepare perfluorosulfonic acid solution and ammonia Polysulfone solution. Mix 8mL of the above-mentioned perfluorosulfonic acid solution and 0.5mL of the above-mentioned ammoniated polysulfone solution, stir magnetically for 1-3 hours, and then ultrasonically disperse for 20-40 minutes, then put the mixed solution in an oven at 40-80°C and let it stand for desorption. Soak for 4-7 hours.

The weight ratio of the perfluorosulfonic acid proton exchange membrane and the ammoniated polysulfone resin in the mixed solution is 16:1.

Pour the uniform mixed solution into the mold for the first heat treatment, that is, dry it in an oven at 40-80°C for 8-14 hours, transfer it to a vacuum oven after cooling down, and perform the second heat treatment, that is, dry it in a vacuum oven for 100-14 hours. Heat treatment at 170° C. for 3 to 6 hours, and then prepare the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery after cooling down. The thickness of the composite membrane is 80 μm.

The all-vanadium redox flow battery is assembled by using the above-mentioned perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery prepared above, wherein the catalytic layer is activated carbon felt, the bipolar plate is graphite plate, the effective area of the composite membrane is 4cm ² , and the current density is 40mA·cm ^-2 , the concentration of vanadium ions in the electrolyte is 1.5mol·L ^-1 , and the concentration of sulfuric acid is 3mol·L ^-1 .

The all-vanadium redox flow battery was tested, and the test results were: the Coulombic efficiency of the all-vanadium redox flow battery was 96.4%, the voltage efficiency was 89%, and the energy efficiency was 85.8%.

Example 2

Other conditions were the same as in Example 1, except that in the mixed solution, the perfluorosulfonic acid solution was 7 mL, and the ammoniated polysulfone solution was 2 mL. The weight ratio of the perfluorosulfonic acid proton exchange membrane and the ammoniated polysulfone resin in the mixed solution is 7:2.

The prepared composite film has a thickness of 84 μm.

The all-vanadium redox flow battery was tested, and the test results were: the Coulombic efficiency of the all-vanadium redox flow battery was 97%, the voltage efficiency was 86%, and the energy efficiency was 83.4%.

Example 3

Other conditions were the same as in Example 1, except that in the mixed solution, the perfluorosulfonic acid solution was 7 mL, and the ammoniated polysulfone solution was 1 mL. The weight ratio of the perfluorosulfonic acid proton exchange membrane and the ammoniated polysulfone resin in the mixed solution is 7:1.

The prepared composite film has a thickness of 78 μm.

The all-vanadium redox flow battery was tested, and the test results were: the Coulombic efficiency of the all-vanadium redox flow battery was 95.2%, the voltage efficiency was 88%, and the energy efficiency was 83.8%.

Comparative example 1

Dissolve 5 g of the pretreated discarded perfluorosulfonic acid proton exchange membrane in 45 mL of N-methylpyrrolidone solvent to prepare a perfluorosulfonic acid solution. Take 8.5mL of the above-mentioned perfluorosulfonic acid solution, stir it magnetically for 1-3h, then ultrasonically disperse it for 20-40min, then put the solution in an oven at 40-80°C and let it stand for 4-7h.

Pour the uniform solution into the mold for the first heat treatment, that is, dry in an oven at 40-80°C for 8-14 hours, transfer to a vacuum oven after cooling down, and perform the second heat treatment, that is, dry in a vacuum oven at 100-170 ℃ heat treatment for 3-6 hours, and after cooling down, the perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery was prepared, and the thickness of the composite membrane was 80 μm.

The all-vanadium redox flow battery is assembled by using the above-mentioned perfluorosulfonic acid composite membrane for the all-vanadium redox flow battery prepared above, wherein the catalytic layer is activated carbon felt, the bipolar plate is graphite plate, the effective area of the composite membrane is 4cm ² , and the current density is 40mA·cm ^-2 , the concentration of vanadium ions in the electrolyte is 1.5mol·L ^-1 , and the concentration of sulfuric acid is 3mol·L ^-1 .

The all-vanadium redox flow battery was tested, and the test results were: the Coulombic efficiency of the all-vanadium redox flow battery was 90.6%, the voltage efficiency was 90.2%, and the energy efficiency was 81.7%.

It can be seen from the performance of the all-vanadium redox flow battery prepared in the above-mentioned Examples 1-3 and Comparative Example 1 that the introduction of ammoniated polysulfone (APSF) has greatly improved the Coulombic efficiency of the prepared composite membrane. , the voltage efficiency has not changed much, so the energy efficiency has been significantly improved. The rigid structure of the ammoniated polysulfone resin increases the mechanical stability of the composite membrane and reduces the swelling of the composite membrane, so that the battery assembled with the composite membrane exhibits low water mobility and vanadium ion permeability.

Fig. 1 is the SEM surface topography diagram of the composite film prepared in Example 1 and Comparative Example 1.

Figure 2 is the charge and discharge curves of the composite membranes prepared in Example 1 and Comparative Example 1 in an all-vanadium redox flow battery.

As can be seen from Fig. 1, find that the Nafion film of comparative example 1 (as shown in Figure 1a) has a smooth surface through comparison, and the surface of the composite film of Example 1 (as shown in Figure 1b) appears to be evenly dispersed many No phase separation was observed for the white particles and some veins. This shows that APSF is uniformly dispersed in Nafion membrane, and the two have good compatibility.

It can be seen from FIG. 2 that the charging voltage of the all-vanadium redox flow battery in Example 1 is lower than 1.45V, and the discharging voltage is higher than 1.35V. Compared with Comparative Example 1, the resistance of the composite film of the all-vanadium redox flow battery assembled in Example 1 increases due to the addition of APSF, so the charging voltage is higher than that of Comparative Example 1, and the discharge voltage is lower than that of Comparative Example 1.

The batteries prepared in Examples 1-3 and Comparative Example 1 are all-vanadium redox flow batteries, and the coulombic efficiency is determined by the selectivity of the membrane to vanadium ions. High coulombic efficiency indicates that the self-discharge degree of the battery is relatively low. Energy efficiency reflects the energy utilization rate of the battery, which is equal to the product of Coulomb efficiency and voltage efficiency. Although comparative example 1 has higher voltage efficiency, the coulombic efficiency is relatively low and the degree of self-discharge is high, so the energy conversion rate is also relatively low. Therefore, it is not suitable for all-vanadium redox flow batteries.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-mentioned embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a kind of preparation method of perfluorinated sulfonic acid composite membrane, includes the following steps:

(1) mixed solution of the polysulfone resin after perfluorosulfonic acid proton exchange film and ammoniated treatment is prepared；

(2) mixed solution of step (1) is contacted with substrate, is heat-treated twice, it is compound that the perfluorinated sulfonic acid is prepared Film.

2. preparation method according to claim 1, which is characterized in that step (1) includes the following steps:

Polysulfone resin after perfluorosulfonic acid proton exchange film and ammoniated treatment is dissolved in organic solvent respectively, perfluor is prepared Sulfonic acid solutions and ammonification polysulfones solution, the two is mixed, mixed solution is prepared.

3. preparation method according to claim 1 or 2, which is characterized in that step (1) includes the following steps:

Polysulfone resin after pretreated perfluorosulfonic acid proton exchange film and ammoniated treatment is dissolved in organic solvent respectively, is made It is standby to obtain perfluorinated sulfonic acid solution and ammonification polysulfones solution, the two is mixed, through 1~3h of magnetic agitation, 20~40min of ultrasonic disperse 4~7h is stood at a temperature of 40~80 DEG C afterwards, mixed solution is prepared.

4. preparation method according to claim 1-3, which is characterized in that in step (1), the perfluorinated sulfonic acid matter Proton exchange is selected from pretreated perfluorosulfonic acid proton exchange film, or selected from discarded perfluorosulfonic acid proton exchange film, Either it is selected from pretreated discarded perfluorosulfonic acid proton exchange film；

Preferably, in step (1), the organic solvent is n,N-Dimethylformamide, n,N-Dimethylformamide, N, N- diformazan At least one of yl acetamide, dimethyl sulfoxide or N-Methyl pyrrolidone.

5. preparation method according to claim 1-4, which is characterized in that in step (1), the perfluorinated sulfonic acid is molten The weight concentration of perfluorosulfonic acid proton exchange film is 2~10wt% in liquid, poly- after ammoniated treatment in the ammonification polysulfones solution 2~15wt% of weight concentration of sulphone resin；

Preferably, in step (1), polysulfone resin in the mixed solution after perfluorosulfonic acid proton exchange film and ammoniated treatment Weight ratio is (60~99.999): (0.001~40).

6. preparation method according to claim 1-5, which is characterized in that in step (2), by including but unlimited In casting, dipping, silk-screen, inkjet printing, roller coating, spray painting, spraying, spin coating and/or vapor deposition mode by mixed solution with Substrate contact；

Preferably, in step (2), the substrate is selected from glass, monocrystalline silicon, polytetrafluoroethylene (PTFE) (PTFE), poly terephthalic acid second At least one of diol ester (PET), polyethylene naphthalate (PEN), polyimides (PI) etc..

7. preparation method according to claim 1-6, which is characterized in that the step (2) includes the following steps:

The mixed solution of step (1) is coated to substrate surface, first time heat treatment, cooling are carried out under the conditions of 40~80 DEG C Afterwards, second is carried out under 100~170 DEG C of vacuum conditions to be heat-treated, the perfluorinated sulfonic acid composite membrane is prepared；

Preferably, the step (2) includes the following steps:

The mixed solution of step (1) is coated to substrate surface, in 40~80 DEG C of baking oven carry out for the first time heat treatment 8~ 14h is transferred in vacuum drying oven after cooling, and second of 3~6h of heat treatment is carried out in 100~170 DEG C of vacuum drying ovens, is prepared into To the perfluorinated sulfonic acid composite membrane；

Preferably, the vacuum degree of the vacuum drying oven is 0.01-0.1MPa, for example, 0.08MPa.

8. a kind of perfluorinated sulfonic acid composite membrane, the composite membrane is prepared by the described in any item methods of claim 1-7 's；

Preferably, the perfluorinated sulfonic acid composite membrane with a thickness of 50~150 μm.

9. the purposes of perfluorinated sulfonic acid composite membrane according to any one of claims 8, is used for all-vanadium flow battery.

10. a kind of all-vanadium flow battery, the battery includes perfluorinated sulfonic acid composite membrane according to any one of claims 8.