KR102332293B1 - Reinforced Membrane with low permeability and the preparation as the same - Google Patents

Abstract

The present invention relates to a reinforced composite electrolyte membrane for secondary batteries and a method for manufacturing the same, and more particularly, to a reinforced composite electrolyte membrane having hydration stability, chemical stability and low permeability, a manufacturing method therefor, and a secondary battery including the reinforced composite electrolyte membrane it's about

Description

Reinforced membrane with low permeability and manufacturing method thereof {Reinforced Membrane with low permeability and the preparation as the same}

The present invention relates to a reinforced composite electrolyte membrane for secondary batteries and a method for manufacturing the same, and more particularly, to a reinforced composite electrolyte membrane having hydration stability, chemical stability and low permeability, a manufacturing method therefor, and a secondary battery including the reinforced composite electrolyte membrane it's about

The polymer electrolyte membrane is not a simple thin membrane such as a film, but a polymer membrane having a function of separating materials. Specifically, a polymer capable of cation exchange such as a fuel cell, a redox flow battery, and a water treatment device is used as the electrolyte membrane.

The electrolyte membrane applied to the fuel cell and the redox flow cell must be able to separate the positive electrode and the negative electrode, and it is absolutely necessary to have high selective ion permeability that prevents the movement of other active ions while transferring hydrogen ions.

Therefore, at present, ionically conductive polymers (ion resins) such as Nafion are used as electrolyte membrane materials, but Nafion polymers are expensive and, due to their low mechanical strength and high permeability, are used as electrolyte membranes for long-term batteries. There are limits to its application.

As a result, polymer electrolyte membranes have been developed in the direction of improving mechanical and chemical durability. In order to improve mechanical durability, reinforced composite electrolyte membranes prepared by introducing Nafion solution (5 wt% concentration) into e-PTFE (U.S. Patent No. 5,547,551) and a study on a polymer blend composite membrane in which a polymer having excellent dimensional stability is introduced into a sulfonated hydrocarbon-based polymer material (Korean Patent No. 10-0746339). In addition, W.L. Gore & Associates is launching a commercialized reinforced composite electrolyte membrane product under the trade name of Gore Select.

As such, the known reinforced composite electrolyte membrane not only improves mechanical strength, durability, and selective permeability, but also has the advantage of being cheaper to manufacture than pure polymers. However, in the prior art, it is difficult to impregnate the ionic polymer into the nano-sized pores, and there is a problem in that the ionic polymer is separated from the porous substrate when the battery is operated for a long time. In addition, since the porous substrate itself does not have an ion transport ability, there is a disadvantage in that the conductivity decreases as much as the ratio of the porous substrate compared to a pure ionic polymer.

To compensate for these disadvantages, most of the hydrophobic porous substrates used in the reinforced composite electrolyte membrane are coated with a hydrophilic polymer such as polyvinyl alcohol (PVA). Here, the hydroxyl group (-OH) of the coated polyvinyl alcohol helps the ion conductive polymer to be impregnated into the pores of the porous substrate by modifying the hydrophobic polymer to be hydrophilic. However, the porous material itself has no ion transport ability, and the hydroxyl group of the coated polyvinyl alcohol also does not play a large role in hydrogen transport due to its high pKa (10.67). In order to solve this problem, a technique for improving affinity between a porous substrate and an ionic polymer by substituting a hydrophilic functional group with an ionic functional group has been proposed.

However, the proposed technique has a problem in that not only the manufacturing process is complicated, but also the permeability is still high due to the impregnated ionic polymer.

As a result of research efforts, the present inventors have completed the present invention by changing the composition of the ion conductive polymer material impregnated in the porous substrate to develop a reinforced composite electrolyte membrane having superior durability and low permeability.

Accordingly, it is an object of the present invention to provide a reinforced composite electrolyte membrane having hydration stability and low permeability while ensuring strong durability through a porous substrate, a method for manufacturing the same, and an energy storage device and a water treatment device comprising the reinforced composite electrolyte membrane .

The object of the present invention is not limited to the object mentioned above, and even if not explicitly mentioned, the object of the invention that can be recognized by those of ordinary skill in the art from the description of the detailed description of the invention to be described later may also be included. .

In order to achieve the object of the present invention described above, first the present invention provides a porous polymer support; a dopamine coating layer formed on all surfaces of the polymer support exposed to the outside, including the pores of the polymer support; and an ion transport layer formed to cover the dopamine coating layer.

The porous polymer support is made of polyphenylene sulfide (PPS) or sulfonated polyphenylene sulfide (sPPS),

The ion transport layer includes a silica-based polymer material and an ion conductive material in a weight ratio of 1:3 to 3:1, and the silica-based polymer material is D-ASFP (Diol Alkoxysilane-functionalized Polymer), BD-ASFP (bisphenol dimethyl benzanthracene ASFP) or BDP-ASFP (Polydimethylsiloxane ASFP),

When the porous polymer support is sulfonated polyphenylene sulfide (sPPS), it is obtained by sulfonating polyphenylene sulfide (PPS) on a porous membrane, and the ion conductive material is Nafion, 3M ionomer, sulfonated fluorine polymers, benzimidazole polymers, polyimide polymers, polyamide polymers, polyarylene ether polymers, polyetherimide polymers, polyphenylene sulfide polymers, polysulfone polymers, polyethersulfone polymers, Polyether ketone-based polymer, polyether-etherketone-based polymer, polyphosphazene-based polymer, polystyrene-based polymer, radiation-grafted FEP-g-polystyrene, radiation-grafted FEP-g-polystyrene and at least one hydrogen ion conductive polymer selected from radiation-grafted PVDF-g-polystyrene and polyphenylquinoxaline-based polymers.

In a preferred embodiment, the transmittance is ^{less than or equal to 2.00×10 -6} cm 2 /min.

In addition, the present invention comprises the steps of preparing a dopamine solution; preparing a precursor film in which a dopamine coating layer is formed on all surfaces of the porous polymer support exposed to the outside by immersing the porous polymer support in the dopamine solution; and forming an ion transport layer on the surface of the precursor film.

The porous polymer support is made of polyphenylene sulfide (PPS) or sulfonated polyphenylene sulfide (sPPS),

The forming of the ion transport layer may include: preparing a solution for forming an ion transport layer in which a silica-based polymer material and an ion conductive material are included in a weight ratio of 1:3 to 3:1; coating the solution for forming the ion transport layer on the surface of the precursor film; and drying the ion transport layer;

The silica-based polymer material is any one of D-ASFP (Diol Alkoxysilane-functionalized Polymer), BD-ASFP (bisphenol dimethylbenzanthracene ASFP), BDP-ASFP (Polydimethylsiloxane ASFP),

When the porous polymer support is sulfonated polyphenylene sulfide (sPPS), it is obtained by sulfonating polyphenylene sulfide (PPS) on a porous membrane,

The ion conductive material is Nafion, 3M ionomer, sulfonated fluorine-based polymer, benzimidazole-based polymer, polyimide-based polymer, polyamide-based polymer, polyarylene ether-based polymer, polyetherimide-based polymer, polyphenyl Rensulfide-based polymer, polysulfone-based polymer, polyethersulfone-based polymer, polyetherketone-based polymer, polyether-etherketone-based polymer, polyphosphazene-based polymer, polystyrene-based polymer, radiation-grafted FEP-g- At least one hydrogen ion conductive polymer selected from polystyrene (radiation-grafted FEP-g-polystyrene), radiation-grafted PVDF-g-polystyrene, and polyphenylquinoxaline-based polymers includes

In a preferred embodiment, the step of preparing the dopamine solution comprises the steps of adding dopamine chloride to distilled water and stirring; And after adding Tris (hydroxymethyl) aminomethane to the stirred solution, stirring is performed.

In a preferred embodiment, preparing the precursor film includes washing the porous polymer support immersed in the dopamine solution; and drying the washed porous polymer support.

Also, the present invention provides a fuel cell including any one of the reinforced composite electrolyte membranes described above or a reinforced composite electrolyte membrane manufactured by any one of the manufacturing methods described above.

In addition, the present invention provides a redox flow battery comprising any one of the above-described reinforced composite electrolyte membrane or a reinforced composite electrolyte membrane manufactured by any one of the manufacturing methods described above.

According to the present invention described above, it is possible to provide a reinforced composite electrolyte membrane having hydration stability, chemical stability and low permeability while ensuring strong durability through the porous substrate.

In addition, since the redox flow battery including the reinforced composite electrolyte membrane having low permeability of the present invention has improved ion conductivity as well as ion blocking ability, the performance of the battery can be improved.

These technical effects of the present invention are not limited only to the above-mentioned range, and even if not explicitly mentioned, the effect of the invention that can be recognized by a person of ordinary skill in the art from the description of the specific content for the implementation of the invention to be described later is also of course included.

1 shows the chemical structure of D-ASFP, a silica-based polymer material that can be applied to the present invention.
Figure 2 shows the chemical structure of BD-ASFP, a silica-based polymer material that can be applied to the present invention.
3 shows the chemical structure of BDP-ASFP, a silica-based polymer material that can be applied to the present invention.

The terms used in the present invention have been selected as currently widely used general terms as possible while considering the functions in the present invention, but these may vary depending on the intention or precedent of a person skilled in the art, the emergence of new technology, and the like. In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the description of the corresponding invention. Therefore, the terms used in the present invention should be interpreted based on the general meaning of the term and the content described throughout the specification of the present invention, rather than the name of a simple term. In particular, when the terms "about", "substantially", etc. of degree are used, they may be construed as being used in a sense at or close to the numerical value when manufacturing and material tolerances inherent in the stated meaning are presented. .

The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification is present, and includes one or more other features or It should be understood that the existence or addition of numbers, steps, operations, components, parts, or combinations thereof does not preclude the possibility of addition.

Hereinafter, the technical configuration of the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

However, the present invention is not limited to the embodiments described herein and may be embodied in other forms.

The technical feature of the present invention is that it is possible to improve hydration stability without a separate ionic functional group substitution process by forming a dopamine coating layer on the porous support while ensuring strong durability through the porous support, as well as ion conductive polymer impregnated in the porous substrate An object of the present invention is to provide a reinforced composite electrolyte membrane having low permeability by changing the composition of the material and a method for manufacturing the same.

That is, focusing on the fact that dopamine is not only a hydrophilic material but also has strong adhesive properties, the present invention formed a dopamine coating layer in particular to impart hydrophilicity to the porous support, and the ion transport layer is formed on the dopamine coating layer. This is because the interfacial bonding force between the porous support and the ion transport layer is very strong due to the dopamine coating layer without performing a separate process of substituting the ionic functional group, and as will be described later, the hydration stability is excellent.

In addition, the present invention does not form the ion transport layer formed on the dopamine coating layer only with the ion conductive polymer, but by mixing the silicon-based polymer with the ion conductive polymer in a certain ratio to form it, thereby improving the hydrogen ion conductivity while improving the permeability of other active ions. Remarkably lowered, low transmittance was secured.

Therefore, the reinforced composite electrolyte membrane of the present invention includes a porous polymer support; a dopamine coating layer formed on all surfaces of the polymer support exposed to the outside, including the pores of the polymer support; and an ion transport layer formed to cover the dopamine coating layer.

Here, the ion transport layer may contain a silica-based polymer material and an ion conductive material in a weight ratio of 1:3 to 3:1, and the set range is experimentally determined, and the silica-based polymer is formed when the silica-based polymer is included in excess of the set weight ratio. As a result, there is a problem in that the permeability is lowered and the hydrogen ion conductivity is lowered. When the silica-based polymer material is introduced with less than a set weight ratio, the ion conductivity is improved, and when the ion conductive material is included, the permeability is increased.

Therefore, in the reinforced composite electrolyte membrane of the present invention, the silica-based polymer material and the ion conductive material further improve the hydrogen ion conductivity, and block other active ions, so the transmittance is 1.0 × 10 ^-7 ㎠/min or less It has a very low characteristic. .

As the silica-based polymer material used in the present invention, all known silica-based polymer materials may be used, but as an embodiment, Diol Alkoxysilane-functionalized Polymer (D-ASFP) having the chemical structure shown in FIG. It may be any one of bisphenol dimethyl benzanthracene ASFP (BD-ASFP) having the chemical structure shown, and polydimethylsiloxane ASFP (BDP-ASFP) having the chemical structure shown in FIG. 3, and the weight average molecular weight (Mm) is 50 ~ 　5000 g /mol. When the weight average molecular weight of the silica-based polymer is less than or exceeding the set range, a long time when dissolved in an organic solvent or crosslinking occurs in the polymer, causing many difficulties.

The ion conductive material is also not particularly limited as long as it is a polymer capable of ion exchange with cation conductivity or anion conductivity, and a known conventional material may be used. In particular, Nafion, 3M ionomer, sulfonated fluorine-based polymer, benzimidazole-based polymer, polyimide-based polymer, polyamide-based polymer, polyarylene ether-based polymer, polyetherimide-based polymer, polyphenylene sulfide-based polymer Polymer, polysulfone-based polymer, polyethersulfone-based polymer, polyetherketone-based polymer, polyether-etherketone-based polymer, polyphosphazene-based polymer, polystyrene-based polymer, radiation-grafted FEP-g-polystyrene (radiation) -grafted FEP-g-polystyrene), radiation-grafted PVDF-g-polystyrene (radiation-grafted PVDF-g-poly styrene), and polyphenylquinoxaline-based polymer containing at least one hydrogen ion conductive polymer selected from and more specifically, sulfonated poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), copolymer of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid group, sulfided polyether Ketones, aryl ketones, poly(2,2'-m-phenylene)-5,5'-bibenzimidazole [poly(2,2'-m-phenylene)-5,5'-bibenzimidazole] and poly( 2,5-benzimidazole), sulfonated polysulfone, sulfonated polyethersulfone, sulfonated polyetherethersulfone, sulfonated polyaryleneethersulfone, sulfonated polyetherketone, sulfonated poly Etheretherketone, sulfonated polyimide, sulfonated polybenzimidazole, sulfonated polyphenyleneoxide, sulfonated polyphenylenesulfide, sulfonated polystyrene, sulfonated polyurethane, Nafion, polytri Any one of fluorostyrene sulfonic acid, polystyrene sulfonic acid and branched sulfonated polysulfone ketone copolymer may be used.

The porous polymer support used in the present invention may be composed of any known hydrophobic polymer material as long as it has excellent mechanical durability. PI), polyamide (PA), polycarbonate (PC), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), polyvinyl die Fluorethylene (polyvinyldifluoroethylene), polyvinyl chloride (polyvinyl chloride), polyvinylidene chloride (polyvinylidene chloride), polyether ketone (polyetherketone), polyether ether ketone (PEEK), polyethylene ether nitrile (polyethylene ether nitrile), polyphenyl A porous polymer support made of any one of lensulfide (PPS) and sulfonated polyphenylene sulfide (sPPS) may be used. In particular, in consideration of durability and economy, the material of the porous polymer support may be advantageously polyphenylene sulfide (PPS) and sulfonated polyphenylene sulfide (sPPS).

In particular, when the porous polymer support is sulfonated polyphenylene sulfide (sPPS), the sulfonated polyphenylene sulfide support is obtained by sulfonating the polyphenylene sulfide (PPS) in a film form suitable for use as a porous support. can be obtained

In the present invention, the porous support may be in the form of a fiber or a membrane as a membrane. In particular, in the case of a fiber type, it is a nonwoven fabric that forms a porous web, and includes a spunbond or meltblown type composed of long fibers. Here, the pore size formed in the porous support of the present invention is not particularly limited, but may be 100 nm to 20 μm. If the pore size is less than 100 nm in the porous support, the ion conductive material must fill the pores, but the smaller the pores, the more perfectly It is difficult to fill, and when it exceeds 20 μm, the mechanical strength of the support itself cannot be maintained, and when an ion conductive material is coated, the mechanical strength, which is an excellent property of the existing reinforced composite membrane, may decrease. In addition, the porosity is not particularly limited, but may be in the range of 30 to 80%. That is, if the porosity of the porous support is less than 30%, it is difficult to coat the ion conductive material, and at the same time, the ion conductivity property may decrease due to the small amount of the ion conductive material. In addition to being unable to maintain mechanical strength, when an ion conductive material is coated, mechanical strength, which is an excellent property of the existing reinforced composite membrane, may decrease.

Next, the method for manufacturing a reinforced composite electrolyte membrane of the present invention comprises the steps of preparing a dopamine solution; preparing a precursor film in which a dopamine coating layer is formed on all surfaces of the porous polymer support exposed to the outside by immersing the porous polymer support in the dopamine solution; and forming an ion transport layer on the surface of the precursor film.

At this time, the step of preparing the dopamine solution includes adding dopamine chloride to distilled water and stirring; And after adding Tris(hydroxymethyl)aminomethane to the stirred solution, stirring is performed; it may be effective to maintain the finally obtained dopamine solution in a weakly basic state of pH 8 to pH 9.5. The thickness of the dopamine coating layer formed on the porous support can be adjusted by controlling the concentration and impregnation time of the dopamine solution, and the thickness of the dopamine coating layer can be 10 nm to 1 μm or less, and has some effect on the binding force between the porous support and the ion transport layer. can affect

Preparing the precursor film may include washing the porous polymer support immersed in a dopamine solution; and drying the washed porous polymer support.

The step of forming the ion transport layer comprises the steps of: preparing a solution for forming an ion transport layer containing a silica-based polymer material and an ion conductive material in a weight ratio of 1:3 to 3:1; coating the solution for forming the ion transport layer on the surface of the precursor film; and drying the ion transport layer; particularly, the coating of the ion transport layer may be formed by casting.

At this time, the casting may include all casting methods generally performed such as coating using a comma coater, spin coating, dip coating, slot die coating, or doctor blade coating, but in one embodiment, coating may be performed using a doctor blade. have. In particular, the present invention developed and applied a new coating method that can simplify the manufacturing procedure by coating both surfaces of the precursor film at a time without using a doctor blade as in Examples to be described later. In addition, the drying step may be performed for 10 to 14 hours at 40 to 60 ℃ and then again to be performed at a temperature range of 120 ℃ for 18 to 24 hours.

Example 1

1. Steps to prepare dopamine solution

Dopamine chloride was added to distilled water at a concentration of 1.5 g/L and stirred for 30 minutes. Tris (hydroxymethyl) aminomethane was added to the prepared solution at a concentration of 3.75 mM, and stirred for 10 minutes to dissolve the solution, thereby preparing a dopamine solution.

2. Preparation of precursor membrane

In the prepared dopamine solution, a polymeric support was immersed in a membrane-like PPS porous support having a pore size of 10 to 15 μm, a thickness of 20 to 24 μm, and a porosity of 46 to 60% in the dopamine solution for 12 hours, washed with distilled water, and vacuum at 60° C. By drying in an oven, a precursor film in which a dopamine coating layer was formed on the surface of the PPS material porous support was prepared.

3. Forming an ion transport layer

① Preparing a solution for ion transport layer formation

Put Nafion in DMAc to prepare a 20wt% Nafion solution, and based on 2g of polymer, 0.5g of D-ASFP (Diol Alkoxysilane-functionalized Polymer) and 1.5g of 20wt% Nafon solution are added as a silica-based polymer, SP, with cation conductivity ions A solution for forming a transport layer (NSP) was prepared.

② Coating the ion transport layer

The ion transport layer forming solution (NSP) was applied to the precursor film using a doctor blade to complete the coating of the ion transport layer in one process. That is, the precursor film is placed on the bottom surface in a state where the ion transport layer forming solution (NSP) is on the bottom surface in a certain amount, and then the ion transport layer forming solution (NSP) is again flowed on the surface of the precursor film located on the upper surface in the arranged state. This is because ion transport layers can be formed on all surfaces, including both sides of the precursor film, when the doctor blade is passed through after being wetted.

③ Drying the ion transport layer

The precursor film on which the ion transport layer was formed was first dried at 50° C. for 12 hours. After that, the temperature was raised from 50°C to 20°C every 2 hours, and finally secondary drying was performed at 120°C for 12 hours to obtain a reinforced composite electrolyte membrane 1 (NASP250). The thickness of the finally dried reinforced composite electrolyte membrane 1 was 50±5 μm.

Example 2

Reinforced composite electrolyte membrane 1 (NSSP250) was obtained in the same manner as in Example 1, except that the membrane-type sPPS polymer support obtained by sulfonating the membrane-type PPS polymer support was used instead of the membrane-type PPS polymer support. .

The membrane-type PPS polymer support was sulfonated as follows to obtain a membrane-type sPPS polymer support. First, methanesulfonic acid (MethaneSulfonic Acid) and chlorosulfonic acid (CSA) were added to contain 36 mmol of each in 500 ml of chloromethane, and then dissolved to prepare a sulfonation solution. Thereafter, a sulfonation solution was added to a 1000 ml flask, and the membrane PPS polymer support was immersed. Next, the sulfonation reaction was performed by stirring for 30 hours so that the magnetic bar did not come into contact with the PPS polymer support on the membrane to obtain an electrolyte membrane precursor. Then, the electrolyte membrane precursor was washed 4 times with distilled water. The washed electrolyte membrane precursor was impregnated in 1 mol aqueous solution of sodium hydroxide for 18 hours. After the reaction was completed, the sulfonated polyphenylene sulfide electrolyte membrane (sPPS polymer support on membrane) was prepared by drying in a vacuum oven for 24 hours at 80° C. for 24 hours in a vacuum oven.

Comparative Example 1

Nafion was put in DMAc to prepare a 20wt% Nafion solution, and the membrane PPS porous support used in Example 1 was coated in one process using a doctor blade to form a Nafion layer. After that, it was first dried at 50° C. for 12 hours. In addition, the temperature was raised by 20 °C every 2 hours from 50 °C, and finally secondary drying was performed at 120 °C for 12 hours to obtain Comparative Example reinforced composite electrolyte membrane 1 (NA150). The thickness of Comparative Example reinforced composite electrolyte membrane 1 obtained by final drying was 50±5 μm.

Comparative Example 2

Comparative Example Reinforced Composite Electrolyte Membrane 2 (NA250) was obtained in the same manner as in Comparative Example 1, except that the dopamine layer was formed in the same manner as in Example 1 before forming the Nafion layer on the membrane PPS porous support.

Comparative Example 3

Comparative Example reinforced composite electrolyte membrane 3 (NS150) was obtained in the same manner as in Comparative Example 1, except that the membrane sPPS porous support prepared in Example 2 was used.

Comparative Example 4

Comparative Example reinforced composite electrolyte membrane 4 (NS250) was obtained in the same manner as in Comparative Example 2, except that the membranous sPPS porous support prepared in Example 2 was used.

Comparative Example 5

Comparative Example reinforced composite electrolyte membrane 5 (NASP150) was obtained in the same manner as in Example 1, except that an ion transport layer was directly formed without forming a dopamine coating layer on the membrane PPS porous support.

Comparative Example 6

Comparative Example Reinforced Composite Electrolyte Membrane 6 (NSSP150) was obtained in the same manner as in Example 2, except that the ion transport layer was directly formed without forming the dopamine coating layer on the sPPS porous support.

Experimental Example 1

Reinforced composite electrolyte membranes 1 and 2 (NASP250, NSSP250) obtained in Examples 1 and 2 and Comparative Example reinforced composite electrolyte membranes 1 to 6 (NA150 NA250, NS150, NS250, NASP150, NSSP250) and Nafion obtained in Comparative Examples 1 to 6 For 212 (N212), hydration stability was evaluated as follows, and the results are shown in Table 1.

In order to evaluate the stability between the polymer support included in the reinforced composite electrolyte membrane and the electrolyte material of the ion transport layer, a stability evaluation experiment was conducted by immersing it in high temperature water for a long time. After measuring the dry weight of the reinforced composite electrolyte membrane, it was fastened to a pressure vessel, heated in an oven at 200° C., and after 3 days, the weight loss of the reinforced composite electrolyte membrane was measured, and the reduction rate was measured through the following equation.

은 반응 강화복합전해질막 무게를,

는 반응 전 강화복합전해질막의 무게를 의미한다.From here

is the weight of the reaction-enhanced composite electrolyte membrane,

is the weight of the reinforced composite electrolyte membrane before the reaction.

division Before After weight change rate
(%) pH change rate
(%) weight
(mg) pH weight
(mg) pH N212 0.052 7.14 X 3.78 X 47.06 NA150 0.023 7.31 0.009 2.44 60.87 66.62 NA250 0.026 7.67 0.024 5.44 7.69 29.07 NS150 0.023 7.01 0.007 2.34 69.56 66.62 NS250 0.027 6.97 0.025 4.74 7.41 31.99 NASP150 0.031 7.56 0.013 2.10 58.06 72.22 NASP250 0.035 7.43 0.034 6.66 2.86 10.36 NSSP150 0.033 7.11 0.010 3.33 69.70 53.16 NSSP250 0.045 7.31 0.041 5.88 8.89 19.56

From Table 1, the weight change, pH change, and weight change of Nafion 212, reinforced composite electrolyte membranes 1 and 2, and comparative example reinforced composite electrolyte membranes 1 to 6 can be confirmed. Nafion 212 was found to be dissolved as a result of reaction at 200 °C for 24 hours and showed a change in pH of 47%. In addition, in NA150, NS150, NASP150, and NSSP150 without dopamine coating on the polymer support, Nafion, a polymer ionomer, melted at high temperature, resulting in a large weight change rate, and the pH change was lowered by the dissolved Nafion. was able to confirm On the other hand, NA250, NS250, NASP250, and NSSP250 coated with dopamine on a polymer support all improved the adhesion between the support and Nafion and NSP, so that physical delamination due to high temperature was small, so it was confirmed that the weight change rate was small.

In particular, NASP250 and NSSP250, which are reinforced composite electrolyte membranes according to the present invention, have a smaller weight change rate than NA250 and NS250, which are comparative example reinforced composite electrolytes in which the ion transport layer is formed only with Nafion, which is the ion transport layer as in the present invention. When the ionic polymer contains more silica-based polymer materials rather than the ionic polymer alone, the ionic polymer has a high affinity between silica-based polymer materials, which further strengthens the adhesion of the ionic polymer to further improve hydration stability. show that

Experimental Example 2

Reinforced composite electrolyte membranes 1 and 2 (NASP250, NSSP250) obtained in Examples 1 and 2 and Comparative Example reinforced composite electrolyte membranes 1 to 6 (NA150 NA250, NS150, NS250, NASP150, NSSP250) and Nafion obtained in Comparative Examples 1 to 6 For 212 (N212), the chemical stability was evaluated as follows, and the results are shown in Table 2.

In order to determine the stability of the reinforced composite electrolyte membrane with respect to V(V), an accelerated experiment was performed as follows. Prepare a solution by dissolving 0.1 M V(V) in 3 M H2SO4. The membrane was immersed in 15 ml of the solution, the solution was sampled 48 hours later, and the amount of V(V) reduced to V(IV) was measured with a UV-VIS Spectrophotometer, and the wavelength used for the measurement was 765.5 nm. Therefore, the process of dissolving the membrane in the vanadium sulfuric acid solution varies depending on the oxidation/reduction state of the solution, and the stability of the membrane over time can be confirmed through this concentration comparison experiment.

division N212 NA
150 NA
250 NS
150 NS
250 NASP
150 NASP250 NSSP150 NSSP250 density
(mmol/L) 0.232 0.133 0.038 0.171 0.087 0.12 0.063 0.091 0.033

Table 2 shows the chemical stability test results for V(V) obtained by impregnating each reinforced composite electrolyte membrane in 0.1M V(V)/3.0M H2SO4 solution, and performing accelerated experiments for 48 hours. From Table 2, it can be confirmed that the reinforced composite electrolyte membranes are chemically more stable with respect to V(V) than Nafion 212. In addition, among the reinforced composite electrolyte membranes, the NA250, NS250, NASP250, and NSSP250 reinforced composite electrolyte membranes coated with dopamine on a polymer support show higher stability than the NA150, NS150, NASP150, and NSSP150 reinforced composite electrolyte membranes that are not coated with dopamine. . This serves to improve durability by preventing the -OH groups of dopamine from reducing V(V) ions.

In addition, NASP150, NASP250, NSSP150, and NSSP250, which are reinforced composite electrolyte membranes in which the ion transport layer contains ionic polymers and silica-based polymers, show superior durability compared to other reinforced composite electrolyte membranes, which are the components of the ion transport layer. A hydrogen bond is formed inside the NSP, and this hydrogen bond appears to play a role in preventing oxidation ^{of V 5+ ions.} In addition, NASP250 and NSSP250, which are coated with dopamine on the support, show the best durability, and it is judged that the durability is improved by dopamine and NSP.

Experimental Example 3

Reinforced composite electrolyte membranes 1 and 2 (NASP250, NSSP250) obtained in Examples 1 and 2 and Comparative Example reinforced composite electrolyte membranes 1 to 6 (NA150 NA250, NS150, NS250, NASP150, NSSP250) and Nafion obtained in Comparative Examples 1 to 6 For 212 (N212), transmittance was measured as follows, and the results are shown in Table 3.

To measure the permeability of the reinforced composite electrolyte membrane, Nafion 212 and the manufactured reinforced composite electrolyte membrane were assembled in a unit cell for VRFB. The equipment configuration at this time is the same as the cell test, and different solutions (MgSO4 solution and VOSO4 solution) were put into the tank and prepared. In order to achieve electronic equilibrium, a solution in which 1.5M MgSO4 was dissolved in 3M H2SO4 was put in one tank, and a solution in which 1.5M VOSO4 was dissolved in 3M H2SO4 was put in the other tank, and the experiment was conducted. The solution in the tank containing the MgSO4 solution was sampled at intervals of 1, 2, 4, 8, 12, and 24 hours. The amount of transmitted V(IV) was measured using UV, and the wavelength used for the measurement was 765.5 nm. The transmittance (D) was calculated by the following formula.

는 MgSO4 용액의 부피,

는 MgSO4의 투과된 V(Ⅳ)이온의 농도이며,

는 시간,

는 반응 면적,

은 막 두께,

는 VOSO4의 초기 농도이다.here

is the volume of the MgSO4 solution,

is the concentration of permeated V(IV) ions of MgSO4,

is the time,

is the reaction area,

silver film thickness,

is the initial concentration of VOSO4.

division N212 NA
150 NA
250 NS
150 NS
250 NASP
150 NASP
250 NSSP
150 NSSP
250 permeability
(cm2/min) 2.47×10 ^-7 1.7×10 ^-7 8.43×10 ^-8 3.33×10 ^-7 2.44×10 ^-8 1.45×10 ^-8 1.01×10 ^-8 2.11×10 ^-8 0.9×10 ^-8

Table 3 shows the permeability of V(IV) ions of Nafion 212, reinforced composite electrolyte membranes. In the case of Nafion 212, the permeability was measured to be 2.47×10-7 cm2/min, and the reinforced composite electrolyte membranes showed lower permeability than Nafion 212. Among the reinforced composite electrolyte membranes, dopamine-coated NA250, NS250, NASP250, and NSSP250 reinforced composite electrolyte membranes show low permeability. It seems that, despite the porous support, the interfacial adhesion between the Nafion ionomer and the support was improved by dopamine, and the permeation of V(IV) was suppressed despite the Nafion ionomer, showing low permeability.

In addition, the NASP150, NASP250, NSSP150, and NSSP250 reinforced composite electrolyte membranes containing silica-based polymers show lower permeability than other reinforced composite electrolyte membranes. It is confirmed that the selective permeation of V ions occurs by silica. In view of this, NSP constituting the ion transport layer in the reinforced composite electrolyte membrane of the present invention is judged to be an optimal material capable of suppressing permeability.

Although the present invention has been illustrated and described with reference to preferred embodiments as described above, it is not limited to the above-described embodiments, and those of ordinary skill in the art to which the present invention pertains within the scope not departing from the spirit of the present invention Various changes and modifications will be possible.

Claims (7)

porous polymer support; a dopamine coating layer formed on all surfaces of the polymer support exposed to the outside, including the pores of the polymer support; and an ion transport layer formed to cover the dopamine coating layer.
The porous polymer support is made of polyphenylene sulfide (PPS) or sulfonated polyphenylene sulfide (sPPS),
The ion transport layer contains a silica-based polymer material and an ion conductive material in a weight ratio of 1:3 to 3:1,
The silica-based polymer material is any one of D-ASFP (Diol Alkoxysilane-functionalized Polymer), BD-ASFP (bisphenol dimethylbenzanthracene ASFP), BDP-ASFP (Polydimethylsiloxane ASFP),
When the porous polymer support is sulfonated polyphenylene sulfide (sPPS), it is obtained by sulfonating polyphenylene sulfide (PPS) on a porous membrane,
The ion conductive material is Nafion, 3M ionomer, sulfonated fluorine-based polymer, benzimidazole-based polymer, polyimide-based polymer, polyamide-based polymer, polyarylene ether-based polymer, polyetherimide-based polymer, polyphenyl Rensulfide-based polymer, polysulfone-based polymer, polyethersulfone-based polymer, polyetherketone-based polymer, polyether-etherketone-based polymer, polyphosphazene-based polymer, polystyrene-based polymer, radiation-grafted FEP-g- One or more hydrogen ion conductive polymers selected from polystyrene (radiation-grafted FEP-g-polystyrene), radiation-grafted PVDF-g-polystyrene, and polyphenylquinoxaline-based polymers including,
Reinforced composite electrolyte membrane, characterized in that the transmittance is 2.00×10 ^{-6 ㎠/min or less.}
delete preparing a dopamine solution; preparing a precursor film in which a dopamine coating layer is formed on all surfaces of the porous polymer support exposed to the outside by immersing the porous polymer support in the dopamine solution; and forming an ion transport layer on the surface of the precursor film.
The porous polymer support is made of polyphenylene sulfide (PPS) or sulfonated polyphenylene sulfide (sPPS),
The step of forming the ion transport layer comprises the steps of: preparing a solution for forming an ion transport layer containing a silica-based polymer material and an ion conductive material in a weight ratio of 1:3 to 3:1; coating the solution for forming the ion transport layer on the surface of the precursor film; and drying the ion transport layer;
The silica-based polymer material is any one of D-ASFP (Diol Alkoxysilane-functionalized Polymer), BD-ASFP (bisphenol dimethylbenzanthracene ASFP), BDP-ASFP (Polydimethylsiloxane ASFP),
When the porous polymer support is sulfonated polyphenylene sulfide (sPPS), it is obtained by sulfonating polyphenylene sulfide (PPS) on a porous membrane,
The ion conductive material is Nafion, 3M ionomer, sulfonated fluorine-based polymer, benzimidazole-based polymer, polyimide-based polymer, polyamide-based polymer, polyarylene ether-based polymer, polyetherimide-based polymer, polyphenyl Rensulfide-based polymer, polysulfone-based polymer, polyethersulfone-based polymer, polyetherketone-based polymer, polyether-etherketone-based polymer, polyphosphazene-based polymer, polystyrene-based polymer, radiation-grafted FEP-g- One or more hydrogen ion conductive polymers selected from polystyrene (radiation-grafted FEP-g-polystyrene), radiation-grafted PVDF-g-polystyrene, and polyphenylquinoxaline-based polymers including,
A method for manufacturing a reinforced composite electrolyte membrane, characterized in that the permeability of the reinforced composite electrolyte membrane is 2.00×10 ^{-6 ㎠/min or less.}
4. The method of claim 3,
The step of preparing the dopamine solution includes adding dopamine chloride to distilled water and stirring; And Tris (hydroxymethyl) aminomethane is added to the stirred solution and then stirred.
4. The method of claim 3,
Preparing the precursor film may include washing the porous polymer support immersed in the dopamine solution; and drying the washed porous polymer support.
A fuel cell comprising the reinforced composite electrolyte membrane of claim 1 or the reinforced composite electrolyte membrane manufactured by the manufacturing method of any one of claims 3 to 5.
A redox flow battery comprising the reinforced composite electrolyte membrane of claim 1 or the reinforced composite electrolyte membrane manufactured by the manufacturing method of any one of claims 3 to 5.

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