Perfluorosulfonic acid resin modified liquid, preparation method and use thereof

Abstract

The present invention aims to disclose a perfluorosulfonic acid resin modifying liquid, a preparation method and a use thereof, and relates to the technical field of perfluorosulfonic acid modification and ion exchange membrane. The perfluorosulfonic acid resin modifying liquid comprises a perfluorosulfonic acid resin modifying material and a solvent; the perfluorosulfonic acid resin modifying material comprises a perfluorosulfonic acid resin, polyvinyl alcohol, a triethanolamine metal complex and a cross-linking agent in a mass ratio of 100:(5-15):(4-8):(2-6), and the solvent comprises ethanol, dimethyl sulfoxide and water. The invention has the following beneficial effects: the hydroxyl groups of the polyvinyl alcohol interact with the sulfonic acid groups of the perfluorosulfonic acid resin to form a hydrogen bond pre-cross-linking network; the triethanolamine metal complex forms a stable coordination-complexation with the perfluorosulfonic acid resin and the polyvinyl alcohol; the aldehyde group of the aldehyde-containing cross-linking agent and the sulfonic acid group of the perfluorosulfonic acid resin and the hydroxyl group of the polyvinyl alcohol form a pre-cross-linking network; the perfluorosulfonic acid resin modifying liquid forms a coordination-complexation-pre-cross-linking network, and further heat treatment is performed to obtain an ion exchange functional layer with a low swelling rate.

Description

Technical Field

[0001] The invention relates to the technical field of perfluorosulfonic acid modification and ion exchange membranes, and in particular to a perfluorosulfonic acid resin modified liquid, a preparation method and application thereof. Background Art

[0002] Traditional perfluorosulfonic acid ion exchange membranes have two forms: one is a self-supporting form, that is, it is composed entirely of perfluorosulfonic acid resin, and the other is a polymer membrane or mesh supported form, that is, the perfluorosulfonic acid resin is filled in the pores of the membrane or mesh and wrapped on both surfaces; traditional perfluorosulfonic acid ion exchange membrane preparation methods mainly include the salivation method and the hot melt method.

[0003] Whether using the salivation method or the hot melt method, the swelling rate of perfluorosulfonic acid resin after being immersed in electrolyte or water is relatively high, resulting in unstable dry and wet dimensions of the ion exchange membrane. The more perfluorosulfonic acid resin is used, the more unstable the ion exchange membrane size is. In addition, perfluorosulfonic acid resin is relatively expensive. When using the salivation method and the hot melt method, the amount of perfluorosulfonic acid resin used is large, making the ion exchange membrane costly and dimensionally unstable. The ion exchange membrane formed by the polymer film or mesh as the support layer has perfluorosulfonic acid resin on both sides of the ion exchange membrane and is also embedded in the pores of the polymer film or mesh, resulting in a long ion transfer path and insufficient ion transfer efficiency.

[0004] In view of this, there is an urgent need to develop a perfluorosulfonic acid resin modified liquid, a preparation method and its use to overcome the above-mentioned defects. Summary of the Invention

[0005] The purpose of the present invention is to disclose a perfluorosulfonic acid resin modified liquid, a preparation method and an application thereof.

[0006] The first object of the present invention is to develop a perfluorosulfonic acid resin modified liquid.

[0007] The second object of the present invention is to develop a method for preparing a perfluorosulfonic acid resin modified liquid.

[0008] The third object of the present invention is to develop a use of a perfluorosulfonic acid resin modified liquid.

[0009] In order to achieve the above first invention object, the present invention provides a perfluorosulfonic acid resin modified liquid,

[0010] The perfluorosulfonic acid resin modified liquid comprises a perfluorosulfonic acid resin modified material and a solvent;

[0011] The perfluorosulfonic acid resin modified material includes a perfluorosulfonic acid resin, polyvinyl alcohol, a triethanolamine metal complex and a cross-linking agent in a mass ratio of 100:(5-15):(4-8):(2-6), and the solvent includes ethanol, dimethyl sulfoxide and water;

[0012] The cross-linking agent is an aldehyde-containing cross-linking agent or a carboxyl-containing cross-linking agent.

[0013] Preferably, the triethanolamine metal complex is triethanolamine chelated titanium or triethanolamine chelated zirconium.

[0014] Preferably, the aldehyde-containing cross-linking agent is terephthalaldehyde or glutaraldehyde;

[0015] The carboxyl-containing cross-linking agent is maleic acid.

[0016] Preferably, the hydroxyl groups of the polyvinyl alcohol interact with the sulfonic acid groups of the perfluorosulfonic acid resin to form a hydrogen bond pre-crosslinked network;

[0017] The triethanolamine metal complex forms a stable coordination-complex with the perfluorosulfonic acid resin and polyvinyl alcohol;

[0018] The aldehyde group of the aldehyde-containing cross-linking agent / the carboxyl group of the carboxyl-containing cross-linking agent and the sulfonic acid group of the perfluorosulfonic acid resin form a pre-cross-linked network;

[0019] The aldehyde group of the aldehyde-containing crosslinking agent / the carboxyl group of the carboxyl-containing crosslinking agent and the hydroxyl group of the polyvinyl alcohol form a hydrogen bond pre-crosslinking network.

[0020] Preferably, the mass fraction of the perfluorosulfonic acid resin modified material is 1%-5%.

[0021] Based on the same inventive principle, in order to achieve the above-mentioned second invention object, the present invention provides a method for preparing a perfluorosulfonic acid resin modified liquid, characterized in that it comprises the following steps:

[0022] Step S1: adding water and dimethyl sulfoxide in a mass ratio of 100:(5-25) to a first corrosion-resistant reaction kettle, and slowly adding polyvinyl alcohol in a mass ratio of 0.4%-0.8% under stirring, stirring for 30 minutes to 60 minutes, and then standing for 2 hours to 3 hours to swell; heating to 70°C-90°C under stirring until the polyvinyl alcohol solution is completely transparent, continuing to stir for 1 hour to 2 hours, and cooling the polyvinyl alcohol solution to 30°C to prepare a first component;

[0023] Step S2: adding ethanol, a cross-linking agent, and an alcohol solution of a triethanolamine metal complex in a mass ratio of 100: (0.105-0.320): (0.160-0.480) to a second corrosion-resistant reaction kettle, slowly adding water and a perfluorosulfonic acid alcohol aqueous solution after complete dissolution, and stirring for 2h-3h to prepare a second component, wherein the cross-linking agent is an aldehyde-containing cross-linking agent or a carboxyl-containing cross-linking agent;

[0024] Step S3: Stir the first component and slowly add the second component to the first component, stirring continuously for 2h-3h;

[0025] Step S4: filtering with a filter having a precision of 5 μm to 20 μm to obtain a perfluorosulfonic acid resin modified liquid having a mass fraction of 1% to 5%.

[0026] Preferably, the triethanolamine metal complex is triethanolamine chelated titanium or triethanolamine chelated zirconium.

[0027] Preferably, the aldehyde-containing cross-linking agent is terephthalaldehyde or glutaraldehyde;

[0028] The carboxyl-containing cross-linking agent is maleic acid.

[0029] Preferably, the hydroxyl groups of the polyvinyl alcohol interact with the sulfonic acid groups of the perfluorosulfonic acid resin to form a hydrogen bond pre-crosslinked network;

[0030] The triethanolamine metal complex forms a stable coordination-complex with the perfluorosulfonic acid resin and polyvinyl alcohol;

[0031] The aldehyde group of the aldehyde-containing cross-linking agent / the carboxyl group of the carboxyl-containing cross-linking agent and the sulfonic acid group of the perfluorosulfonic acid resin form a pre-cross-linked network;

[0032] The aldehyde group of the aldehyde-containing crosslinking agent / the carboxyl group of the carboxyl-containing crosslinking agent and the hydroxyl group of the polyvinyl alcohol form a hydrogen bond pre-crosslinking network.

[0033] Based on the same inventive principle, in order to achieve the above-mentioned third invention purpose, the present invention provides a use of a perfluorosulfonic acid resin modified liquid. The perfluorosulfonic acid resin modified liquid described in the first invention is used to form an ion exchange functional layer on one surface of a hydrophilic polytetrafluoroethylene support membrane or a hydrophilic polypropylene support membrane.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The hydroxyl groups of the polyvinyl alcohol interact with the sulfonic acid groups of the perfluorosulfonic acid resin to form a hydrogen bond pre-crosslinking network; the triethanolamine metal complex forms a stable coordination-complexation with the perfluorosulfonic acid resin and polyvinyl alcohol; the aldehyde group of the aldehyde-containing crosslinking agent / the carboxyl group of the carboxyl-containing crosslinking agent and the sulfonic acid group of the perfluorosulfonic acid resin form a pre-crosslinking network; the aldehyde group of the aldehyde-containing crosslinking agent / the carboxyl group of the carboxyl-containing crosslinking agent and the hydroxyl groups of the polyvinyl alcohol form a hydrogen bond pre-crosslinking network, and the perfluorosulfonic acid resin modified liquid forms a coordination-complexation-pre-crosslinking network, which is then phase-inverted and thermally crosslinked on a hydrophilic polytetrafluoroethylene support membrane or a hydrophilic polypropylene support membrane. When an ion exchange functional layer is formed on one surface of the support membrane, the self-assembly deposition of the perfluorosulfonic acid resin modified material enables the defects on the ion exchange functional layer to be automatically repaired, significantly improving the reliability of the ultra-thin ion exchange functional layer; the ion exchange functional layer forms an indiscriminate, saturated point-like physical anchoring with the surface pore fibers of the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane, greatly increasing the bonding strength between the two materials and maximizing the effective transmission channel; the perfluorosulfonic acid resin modified material residue in the main body of the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane is very low, and no new ion transfer resistance is generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the cross-linking principle of the perfluorosulfonic acid resin modified material of the present invention.

[0037] Figure 2 The figure is a flow chart of the preparation method of the perfluorosulfonic acid resin modified liquid of the present invention.

[0038] Figure 3 This is a cross-sectional view of the perfluorosulfonic acid resin ion exchange membrane of the present invention.

[0039] Among them, 1. support membrane; 2. ion exchange functional layer. DETAILED DESCRIPTION

[0040] The present invention is described in detail below with reference to the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in this field based on these embodiments are all within the scope of protection of the present invention.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0042] The specific implementation process of the present invention is described below through multiple embodiments.

[0043] Example 1:

[0044] This embodiment discloses a perfluorosulfonic acid resin modified liquid, which includes a perfluorosulfonic acid resin modified material and a solvent; the perfluorosulfonic acid resin modified material includes a perfluorosulfonic acid resin, polyvinyl alcohol, a triethanolamine metal complex, and a cross-linking agent in a mass ratio of 100:(5-15):(4-8):(2-6); the solvent includes ethanol, dimethyl sulfoxide, and water; the mass fraction of the perfluorosulfonic acid resin modified material is 1%-5%; the cross-linking agent is an aldehyde-containing cross-linking agent or a carboxyl-containing cross-linking agent.

[0045] Specifically, the triethanolamine metal complex is the first crosslinking agent, and the aldehyde-containing crosslinking agent / carboxyl-containing crosslinking agent is the second crosslinking agent, wherein the triethanolamine metal complex is triethanolamine chelated titanium or triethanolamine chelated zirconium, the aldehyde-containing crosslinking agent is terephthalaldehyde or glutaraldehyde, and the carboxyl-containing crosslinking agent is maleic acid. In the perfluorosulfonic acid resin modified liquid, the hydroxyl groups of the polyvinyl alcohol interact with the sulfonic acid groups of the perfluorosulfonic acid resin to form a hydrogen bond pre-crosslinking network; the triethanolamine metal complex forms a stable coordination-complex with the perfluorosulfonic acid resin and polyvinyl alcohol; the aldehyde group of the aldehyde-containing crosslinking agent / the carboxyl group of the carboxyl-containing crosslinking agent and the sulfonic acid group of the perfluorosulfonic acid resin form a pre-crosslinking network; the aldehyde group of the aldehyde-containing crosslinking agent / the carboxyl group of the carboxyl-containing crosslinking agent and the hydroxyl group of the polyvinyl alcohol form a hydrogen bond pre-crosslinking network, see for details. Figure 1 Schematic diagram of the cross-linking principle formed, Figure 1 In the embodiment, the triethanolamine metal complex is triethanolamine chelated zirconium, R1, R2, and R3 are independent long-chain fluoroalkyl groups; when the aldehyde-containing crosslinking agent is terephthalaldehyde, x is 6 and y is 4; Figure 1 The chemical formula structure in the polymer forms a three-dimensional network structure, so the swelling rate of the ion exchange functional layer is low. At the same time, polyvinyl alcohol not only provides a monomer component for cross-linking, but also acts as a "medium" for cross-linking other components, which is beneficial to improving proton conductivity and defect self-repair.

[0046] Example 2:

[0047] See also Figure 2 This embodiment discloses a method for preparing a perfluorosulfonic acid resin modified liquid, comprising the following steps:

[0048] Step S1: adding water and dimethyl sulfoxide in a mass ratio of 100:(5-25) to a first corrosion-resistant reaction kettle, and slowly adding polyvinyl alcohol in a mass ratio of 0.4%-0.8% under stirring, stirring for 30 minutes to 60 minutes, and then standing for 2 hours to 3 hours to swell; heating to 70°C-90°C under stirring until the polyvinyl alcohol solution is completely transparent, continuing to stir for 1 hour to 2 hours, and cooling the polyvinyl alcohol solution to 30°C to prepare a first component;

[0049] Step S2: adding ethanol, a cross-linking agent, and an alcohol solution of a triethanolamine metal complex in a mass ratio of 100: (0.105-0.320): (0.160-0.480) to a second corrosion-resistant reaction kettle, slowly adding water and a perfluorosulfonic acid alcohol aqueous solution after complete dissolution, and stirring for 2h-3h to prepare a second component, wherein the cross-linking agent is an aldehyde-containing cross-linking agent or a carboxyl-containing cross-linking agent;

[0050] Step S3: Stir the first component and slowly add the second component to the first component, stirring continuously for 2h-3h;

[0051] Step S4: filtering with a filter having a precision of 5 μm to 20 μm to obtain a perfluorosulfonic acid resin modified liquid having a mass fraction of 1% to 5%.

[0052] The perfluorosulfonic acid resin modified liquid described in Example 1 was prepared through Example 2. The modification mechanism and reaction process of the perfluorosulfonic acid resin modified liquid refer to Example 1 and will not be described again here.

[0053] Example 3:

[0054] See also Figure 3 This embodiment provides a use of a perfluorosulfonic acid resin modified liquid. The perfluorosulfonic acid resin modified liquid described in Example 1 is used to form an ion exchange functional layer on one surface of a hydrophilic polytetrafluoroethylene support membrane or a hydrophilic polypropylene support membrane.

[0055] In a preferred embodiment, the ion exchange functional layer 2 is formed on the surface of the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane 1 by phase inversion and thermal crosslinking to form a single-sided perfluorosulfonic acid resin ion exchange membrane.

[0056] The preparation process of the single-sided perfluorosulfonic acid resin ion exchange membrane is as follows, comprising the following steps:

[0057] Step S1: Immerse the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane into the perfluorosulfonic acid resin modification liquid described in Example 1, and quantify it with a scraper to obtain an impregnated membrane; specifically, the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane has a spontaneous wetting time of less than 5s. Since the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane and the perfluorosulfonic acid resin modification liquid have a very small contact angle, when the hydrophilic porous support membrane is immersed in the perfluorosulfonic acid resin modification liquid, under the strong capillary force of the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane, the perfluorosulfonic acid resin modification liquid is rapidly filled into the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane. After the impregnation is completed, the perfluorosulfonic acid resin modification liquid is evenly laid on the interior and both surfaces of the hydrophilic polytetrafluoroethylene support membrane or the hydrophilic polypropylene support membrane, and an impregnated membrane is formed under the quantitative action of the scraper. The loading amount of the perfluorosulfonic acid resin modification liquid of the impregnated membrane is 40ml / m 2 -150ml / m 2 The preparation method of the perfluorosulfonic acid resin modified liquid is shown in Example 2.

[0058] Polyvinyl alcohol enhances the proton conductivity and defect self-healing ability of the ion exchange functional layer. Triethanolamine chelates zirconium / titanium with delayed crosslinking and strongly chelates with the hydrophilic surface of polytetrafluoroethylene (PTFE) or polypropylene membranes. The high boiling point of terephthalaldehyde / maleic acid effectively increases the temperature and shortens the reaction time of the subsequent crosslinking reaction. These properties and benefits are stable during the single-sided phase transformation and chemical crosslinking film formation of the perfluorosulfonic acid resin modified solution and provide an essential preconditioning for subsequent solid-state chemical crosslinking. The solvent, consisting of ethanol, dimethyl sulfoxide, and water, serves as a carrier for the modified material. Its primary function is to fully dissolve the modified material, so a complex solvent is used. The solvent ratio is adjusted to ensure sufficient stretching of the polymer segments, increase the degree of freedom for assembly, coordination, and complexation between functional groups, improve the permeability of the polymer solution to the base membrane, facilitate programmed evaporation, facilitate coating uniformity, and ensure solution displacement and defoaming capabilities. The perfluorosulfonic acid resin modified solution adopts a low concentration strategy, with the mass concentration of the perfluorosulfonic acid resin modified material controlled at 1-5%.

[0059] Step S2: Laminating a non-porous film on one surface of the impregnated membrane, and passing the laminated membrane through a first evaporation box, a second evaporation box, and a third evaporation box at a speed of 0.5 m / min-3 m / min, wherein the temperature of the first evaporation box is 30° C.-45° C., the temperature of the second evaporation box is 50° C.-65° C., and the temperature of the third evaporation box is 70° C.-85° C. The humidity of the first, second, and third evaporation boxes is 5%-15% and the wind speed is 0.5 m / s-2 m / s, thereby evaporating the solvent in the perfluorosulfonic acid resin modified solution from one side to obtain a composite membrane;

[0060] Specifically, the non-porous film is a PET non-porous film, a PP non-porous film or a stainless steel non-porous film. The non-porous film is taken as an example of a PET non-porous film. A surface evaporation mass transfer method is adopted. The impregnated membrane evaporates the solvent in the perfluorosulfonic acid resin modified liquid according to a predetermined procedure in a space where the temperature, humidity and wind speed are controlled, thereby realizing phase transformation into a membrane. Specifically, a non-porous film is composited on one surface of the impregnated membrane. The non-porous film limits the evaporation of the solvent on this surface, driving the solvent to evaporate through a single side. During the single-surface solvent evaporation process, the perfluorosulfonic acid resin modified liquid continuously migrates to the evaporation surface through the membrane pores of the porous support membrane under the action of the capillary attraction (effect) generated by the micropores of the porous support membrane, and finally accumulates on a surface where evaporation occurs. After the solvent evaporation is completed, a single-sided perfluorosulfonic acid resin ion exchange membrane is obtained.

[0061] Specifically, the composite membrane passes through the first evaporation box, the second evaporation box and the third evaporation box with increasing temperature at a speed of 0.5m / min-3m / min. During the process, the solvent on the single surface of the composite membrane evaporates first, causing the surface of the perfluorosulfonic acid resin modified liquid to rapidly undergo phase transformation and form a cortex of the perfluorosulfonic acid modified material. The solvent in the main body of the perfluorosulfonic acid resin modified liquid continuously diffuses to the cortex under the action of the concentration difference driving force, causing the perfluorosulfonic acid resin modified material to continuously undergo phase transformation on the inner surface of the cortex, forming a self-assembled deposition of the perfluorosulfonic acid resin modified material, and the perfluorosulfonic acid resin modified liquid continuously migrates and is transported to the surface where the phase transformation occurs under the action of the capillary attraction of the hydrophilic polytetrafluoroethylene membrane pores, finally realizing the layered superposition and aggregation of the perfluorosulfonic acid resin modified material. The loading amount of the perfluorosulfonic acid resin modified material is controlled at 1g / m 2 -5g / m 2 Compared to existing "filled composite" structures, the amount of perfluorosulfonic acid resin used is reduced by at least 10 times, resulting in a very high cost-effectiveness. This single-sided phase transformation produces at least three beneficial results: ① The self-assembled deposition of the perfluorosulfonic acid resin modifier automatically repairs defects in the ion exchange functional layer, significantly improving the reliability of the ultra-thin functional layer; ② The ion exchange functional layer forms an indiscriminate, saturated, point-like physical anchoring with the surface pore fibers of the hydrophilic polytetrafluoroethylene microporous membrane, greatly increasing the bonding strength between the two materials and maximizing the effective transfer channel; and ③ The amount of perfluorosulfonic acid modifier remaining in the hydrophilic polytetrafluoroethylene microporous membrane is very low, generating no additional transfer resistance.

[0062] Step S3: The composite membrane is passed through a reaction chamber at a temperature of 100°C-160°C at a speed of 0.5-3 m / min for chemical crosslinking. The non-porous film is then peeled off to produce a single-sided perfluorosulfonic acid resin ion exchange membrane. Specifically, perfluorosulfonic acid resin and polyvinyl alcohol are the two core components of the molecular crosslinking structure, while triethanolamine chelated zirconium and terephthalaldehyde form a composite crosslinking agent. The chemical crosslinking reaction is initiated by heating. The water and alcohol products produced during the crosslinking reaction, as well as the small amount of solvent remaining in the phase-transformed membrane, diffuse out of the ion exchange functional layer. Because the high-boiling-point dimethyl sulfoxide is added to the perfluorosulfonic acid resin modifying solution, the crosslinking reaction proceeds through three stages: semi-solid-phase thermal chemical crosslinking, solid-phase thermal chemical crosslinking, and stress relief. Because the composition, distribution, and interactions of the four components—perfluorosulfonic acid resin, polyvinyl alcohol, triethanolamine chelated zirconium, and terephthalaldehyde—are already pre-determined during the perfluorosulfonic acid resin modifying solution preparation and phase-transformation membrane formation process, the crosslinking reaction is highly controllable, the reaction product is uniform, and the process is convenient and simple.

[0063] Through steps S1 to S3, a single-sided perfluorosulfonic acid resin ion exchange membrane as shown in Example 3 was prepared and tested according to the methods specified in "GB / T 20042.3-2022 Proton Exchange Membrane Fuel Cell Part 3: Proton Exchange Membrane Test Method" and "NB / T 42080-2023 General Technical Requirements and Test Methods for Ion Conducting Membranes for All-Vanadium Redox Flow Batteries". The indicators of the porous support membranes of Examples 1 to 4 are: pore size 0.05 μm, porosity 40%-65%, and water spontaneous wetting time 3 s. In Example 1, the perfluorosulfonic acid resin modified material includes perfluorosulfonic acid resin, polyvinyl alcohol, triethanolamine chelated zirconium and terephthalaldehyde in a mass ratio of 100:9:5:3; in Example 2, the perfluorosulfonic acid resin modified material includes perfluorosulfonic acid resin, polyvinyl alcohol, triethanolamine chelated titanium and pentanediol in a mass ratio of 100:10:6:6. Aldehyde; In Example 3, the perfluorosulfonic acid resin modified material includes perfluorosulfonic acid resin, polyvinyl alcohol, triethanolamine chelated titanium and maleic acid in a mass ratio of 100:11:7:5; In Example 4, the perfluorosulfonic acid resin modified material includes perfluorosulfonic acid resin, polyvinyl alcohol, triethanolamine chelated zirconium and maleic acid in a mass ratio of 100:8:4:2; Comparative Examples 1 and 2 adopt a "filling composite" structure, and the perfluorosulfonic acid resin not only exists on the surface of the porous support membrane, but also fills the pores of the porous support membrane, so that the entire exchange membrane has an ion interaction function, that is, the entire exchange membrane becomes an ion exchange functional layer. The test data is shown in Table 1. After testing, the modified material loading of Examples 1 to 4 is 1g / m 2 -5g / m 2, longitudinal and transverse tensile strength, longitudinal and transverse elongation at break, water swelling rate, longitudinal and transverse thermal deformation and other indicators are shown in Table 1, the thickness of the ion exchange functional layer does not exceed 3μm, and ultra-thinness helps to stabilize the swelling rate of the perfluorosulfonic acid ion exchange membrane, the swelling rate is below 1%, the size is stable, and the ion transfer path is greatly shortened; the functional layer loading amount of Comparative Examples 1 to Comparative Examples 2 is 12 times to 28 times higher than that of Examples 1 to 4, and the cost of the perfluorosulfonic acid resin modified material used in Comparative Examples 1 to 2 is much higher than that of the exchange membranes of Examples 1 to 4. The perfluorosulfonic acid ion exchange membrane was used as the diaphragm of the iron-chromium redox flow battery for charge and discharge tests. The test results are shown in Table 2. When the single-sided perfluorosulfonic acid resin ion exchange membrane is used for fuel cells or all-vanadium redox flow batteries, the coulombic efficiency of the battery is 96.1%-96.7%, the voltage efficiency is 82.2%-86.5%, and the energy efficiency is 79.0%-83.3%. It can be seen that although the modified material loading of Examples 1 to 4 is only 1g / m 2 -5g / m 2 , but it performs well in coulombic efficiency, voltage efficiency and energy efficiency.

[0064] Table 1 Parameter test values ​​of stacked modified perfluorosulfonic acid ion exchange membrane

[0065]

[0066] Table 2 Application performance test values ​​of laminated modified perfluorosulfonic acid ion exchange membrane

[0067]

Claims

1. Perfluorosulfonic acid resin modified liquid, characterized in that, The perfluorosulfonic acid resin modified liquid comprises a perfluorosulfonic acid resin modified material and a solvent; The perfluorosulfonic acid resin modified material comprises perfluorosulfonic acid resin, polyvinyl alcohol, triethanolamine metal complex and cross-linking agent in a mass ratio of 100:(5-15):(4-8):(2-6), and the solvent comprises ethanol, dimethyl sulfoxide and water; The cross-linking agent is an aldehyde-containing cross-linking agent or a carboxyl-containing cross-linking agent.

2. The perfluorosulfonic acid resin modified liquid according to claim 1, wherein The triethanolamine metal complex is triethanolamine chelated titanium or triethanolamine chelated zirconium.

3. The perfluorosulfonic acid resin modified liquid according to claim 1, wherein The aldehyde-containing cross-linking agent is terephthalaldehyde or glutaraldehyde; The carboxyl-containing cross-linking agent is maleic acid.

4. The perfluorosulfonic acid resin modified liquid according to any one of claims 1 to 3, characterized in that: The hydroxyl groups of the polyvinyl alcohol interact with the sulfonic acid groups of the perfluorosulfonic acid resin to form a hydrogen bond pre-crosslinking network; The triethanolamine metal complex forms a stable coordination-complex with the perfluorosulfonic acid resin and polyvinyl alcohol; The aldehyde group of the aldehyde-containing cross-linking agent / the carboxyl group of the carboxyl-containing cross-linking agent and the sulfonic acid group of the perfluorosulfonic acid resin form a pre-cross-linked network; The aldehyde group of the aldehyde-containing crosslinking agent / the carboxyl group of the carboxyl-containing crosslinking agent and the hydroxyl group of the polyvinyl alcohol form a hydrogen bond pre-crosslinking network.

5. The perfluorosulfonic acid resin modified liquid according to claim 4, wherein The mass fraction of the perfluorosulfonic acid resin modified material is 1%-5%.

6. A method for preparing a perfluorosulfonic acid resin modified liquid, characterized in that: The following steps are involved: Step S1: adding water and dimethyl sulfoxide in a mass ratio of 100:(5-25) to a first corrosion-resistant reactor, and slowly adding polyvinyl alcohol in a mass ratio of 0.4%-0.8% under stirring, stirring for 30 minutes to 60 minutes, and then standing for swelling for 2 hours to 3 hours; heating to 70°C to 90°C under stirring until the polyvinyl alcohol solution is completely transparent, continuing to stir for 1 hour to 2 hours, and cooling the polyvinyl alcohol solution to 30°C to prepare a first component; Step S2: adding ethanol, a cross-linking agent, and an alcohol solution of a triethanolamine metal complex at a mass ratio of 100: (0.105-0.320): (0.160-0.480) to a second corrosion-resistant reactor, slowly adding water and an alcohol solution of a perfluorosulfonic acid resin after complete dissolution, and stirring for 2 h to 3 h to prepare a second component, wherein the cross-linking agent is an aldehyde-containing cross-linking agent or a carboxyl-containing cross-linking agent; Step S3: Stir the first component and slowly add the second component to the first component, stirring continuously for 2h-3h; Step S4: Filtering with a filter having a precision of 5 μm to 20 μm to obtain a perfluorosulfonic acid resin modified liquid having a mass fraction of 1% to 5%.

7. The method for preparing a perfluorosulfonic acid resin modified liquid according to claim 6, wherein: The triethanolamine metal complex is triethanolamine chelated titanium or triethanolamine chelated zirconium.

8. The method for preparing a perfluorosulfonic acid resin modified liquid according to claim 6, wherein: The aldehyde-containing cross-linking agent is terephthalaldehyde or glutaraldehyde; The carboxyl-containing cross-linking agent is maleic acid.

9. The method for preparing a perfluorosulfonic acid resin modified liquid according to any one of claims 6 to 8, wherein: The hydroxyl groups of the polyvinyl alcohol interact with the sulfonic acid groups of the perfluorosulfonic acid resin to form a hydrogen bond pre-crosslinking network; The triethanolamine metal complex forms a stable coordination-complex with the perfluorosulfonic acid resin and polyvinyl alcohol; The aldehyde group of the aldehyde-containing cross-linking agent / the carboxyl group of the carboxyl-containing cross-linking agent and the sulfonic acid group of the perfluorosulfonic acid resin form a pre-cross-linked network; The aldehyde group of the aldehyde-containing crosslinking agent / the carboxyl group of the carboxyl-containing crosslinking agent and the hydroxyl group of the polyvinyl alcohol form a hydrogen bond pre-crosslinking network.

10. Use of the perfluorosulfonic acid resin modified liquid according to any one of claims 1 to 5 to form an ion exchange functional layer on one surface of a hydrophilic polytetrafluoroethylene support membrane or a hydrophilic polypropylene support membrane.

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