KR20200141429A - Polymer electrolyte membrane with cosolvent, the method for producing the same and the energy saving device comprising the same. - Google Patents

Abstract

The present invention relates to a polymer electrolyte composite membrane and to a manufacturing method thereof and, more specifically, to a polymer electrolyte composite membrane introducing a composite solvent applied by selecting a composite solvent candidate group and optimizing the ratio through the evaluation of a solvent candidate group capable of maximizing the performance when manufacturing the polymer electrolyte composite membrane, to a manufacturing method of the polymer electrolyte composite membrane, and to an energy storage device comprising the polymer electrolyte composite membrane.

Description

Polymer electrolyte membrane with cosolvent, the method for producing the same and the energy saving device comprising the same. }

The present invention relates to a polymer electrolyte composite membrane and a method of manufacturing the same, and more specifically, through the evaluation of a solvent candidate group capable of maximizing performance when manufacturing a polymer electrolyte composite membrane, a composite solvent candidate group is selected and the ratio is optimized and applied. It relates to a polymer electrolyte composite membrane into which a composite solvent is introduced, a method of manufacturing the polymer electrolyte composite membrane, and an energy storage device including the polymer electrolyte composite membrane.

In the case of an ion exchange membrane applied to an energy storage system (ESS), a perfluorosulfonic acid (PFSA) and a sulfonated hydrocarbon-based polymer are mainly used due to high ion conductivity. However, when the hydrocarbon-based polymer is applied to a fuel cell and an RFB system, it is difficult to apply it to an energy storage device due to low stability of long-term driving due to low chemical stability.

Therefore, in many studies, ion exchange membranes have been manufactured based on PFSA polymers, but due to the high price of PFSA, studies have been conducted to reduce the ratio by blending PFSA and specific materials. As a representative of them, studies have been reported to produce a polymer electrolyte composite membrane that is chemically stable while maintaining ionic conductivity as much as possible by polymerizing inorganic particles.

On the other hand, one of the factors that greatly affect the chemical stability and ionic conductivity of the polymer electrolyte composite membrane is a solvent, and studies that have reported different solvents of hydrocarbon-based polymers have been reported several times, but polymer electrolytes blended with PFSA and inorganic particles. No studies on the composite membrane solvent have been reported.

Korean Patent Publication No. 10-2018-0003098

As a result of a number of studies, the present inventors completed the present invention by applying inorganic particles in the ion conductive polymer and introducing different solvents to derive the optimum solvent and complex solvent through basic physical property evaluation and chemical stability evaluation.

Accordingly, an object of the present invention is a polymer electrolyte composite membrane in which a composite solvent having high ionic conductivity/high chemical stability prepared by selecting a composite solvent for maximizing the performance of the polymer electrolyte composite membrane and an optimum ratio thereof is introduced, the polymer electrolyte It is to provide a composite membrane manufacturing method and an energy storage device including the polymer electrolyte composite membrane.

Another object of the present invention is to improve safety by reducing toxicity during manufacture by using a complex solvent, and to reduce cost by replacing expensive solvents with more inexpensive solvents. The performance of the membrane is to provide a polymer electrolyte composite membrane in which an excellent composite solvent is introduced, a method for manufacturing the polymer electrolyte composite membrane, and an energy storage device including the polymer electrolyte composite membrane.

The object of the present invention is not limited to the above-mentioned object, and even if it is not specifically mentioned, the object of the invention that one of ordinary skill in the art can recognize from the description of the detailed description of the invention to be described later may naturally be included.

In order to solve the problems of the present invention described above, first, the present invention comprises a silica-based functional polymer and an ion conductive polymer in a weight ratio of 1:3 to 3:1,

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

The silica-based functional polymer and the ion conductive polymer provide a polymer electrolyte composite membrane, characterized in that DMAc and NMP are mixed in a weight ratio of 1:3 to 3:1 and dissolved in a composite solvent and bonded to each other.

In a preferred embodiment, the ion conductive polymer is Nafion, 3M ionomer, sulfonated fluorine polymer, benzimidazole polymer, polyimide polymer, polyamide polymer, polyarylene ether polymer, polyetherimide Polymer, polyphenylene sulfide polymer, polysulfone polymer, polyethersulfone polymer, polyetherketone polymer, polyether-etherketone polymer, polyphosphazen polymer, polystyrene polymer, radiation-graft FEP-g-polystyrene (radiation-grafted FEP-g-polystyrene), radiation-grafted PVDF-g-polystyrene (radiation-grafted PVDF-g-polystyrene) and selected from the group consisting of polyphenylquinoxaline polymers Is any one or more.

In addition, the present invention comprises the steps of preparing a complex solvent; Preparing a membrane precursor solution by adding a silica-based functional polymer and an ion conductive polymer to the complex solvent; Casting the film precursor solution to form a precursor film; Drying the precursor film; And pre-treating the dried precursor film;

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

The complex solvent is composed of DMAc and NMP mixed in a weight ratio of 1:3 to 3:1,

The membrane precursor solution contains the silica-based functional polymer and the ion conductive polymer in a weight ratio of 1:3 to 3:1,

The drying step provides a method for manufacturing a polymer electrolyte composite film, characterized in that the precursor film is heated to a temperature of 70° C. or less, 70° C. to 90° C., and 100° C. or more in a vacuum state.

In a preferred embodiment, the pretreatment step is carried out by immersing the dried precursor film in a basic aqueous solution, immersing it in distilled water, immersing it in an acidic aqueous solution, and then immersing it in distilled water.

In addition, the present invention provides an energy storage device including any one of the polymer electrolyte composite membranes described above or the polymer electrolyte composite membrane manufactured by any one of the above-described manufacturing methods.

In a preferred embodiment, the energy storage device is a redox flow cell or a fuel cell.

In addition, the present invention provides a water treatment apparatus including any one of the polymer electrolyte composite membranes described above or the polymer electrolyte composite membrane manufactured by any one of the above-described manufacturing methods.

According to the present invention described above, a composite solvent having high ionic conductivity/high chemical stability prepared by selecting an optimal composite solvent for maximizing the performance of the polymer electrolyte composite membrane by evaluating the polymer electrolyte composite membrane according to the solvent candidate group and the optimal ratio thereof. It is possible to provide a polymer electrolyte composite membrane having introduced.

In addition, according to the present invention, by lowering the ratio of a specific solvent having high toxicity in and using a complex solvent, that is, a complex solvent by mixing a solvent with relatively low toxicity, toxicity is reduced during manufacture, thereby improving safety, and more expensive solvents. It can be replaced with an inexpensive solvent, thereby reducing the cost, and simplifying the manufacturing process to establish an economical polymer electrolyte composite membrane manufacturing process.

These technical effects of the present invention are not limited only to the ranges mentioned above, and even if not explicitly mentioned, the effects of the invention that can be recognized by those of ordinary skill in the art from the description of specific details for the implementation of the invention described later are also Of course it is included.

1 shows the structural formula of D-ASFP (Diol Alkoxysilane-functionalized Polymer), an embodiment of a silica-based functional polymer included in the polymer electrolyte composite membrane of the present invention.
FIG. 2 shows the structural formula of a bisphenol dimethylbenzanthracene Alkoxysilane-functionalized Polymer (BD-ASFP), which is another embodiment of a silica-based functional polymer included in the polymer electrolyte composite membrane of the present invention.
3 shows the structural formula of BDP-ASFP (Polydimethylsiloxane Alkoxysilane-functionalized Polymer), another embodiment of the silica-based functional polymer included in the polymer electrolyte composite film of the present invention.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other features or It is to be understood that the presence or addition of numbers, steps, actions, components, parts, or combinations thereof does not preclude the possibility of preliminary exclusion.

Terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present invention. Does not.

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 same reference numerals used to describe the present invention throughout the specification denote the same elements.

Technical features of the present invention are a polymer electrolyte composite membrane in which a composite solvent having high ionic conductivity/high chemical stability prepared by selecting a composite solvent for maximizing the performance of the polymer electrolyte composite membrane and an optimum ratio thereof is introduced, the polymer electrolyte composite It is in the method of manufacturing the membrane.

That is, one of the factors that have a great influence on the chemical stability and ion conductivity of the polymer electrolyte composite membrane is the solvent used during manufacture, so the silica-based functional polymer and the ion conductive polymer used to introduce inorganic particles into the polymer electrolyte composite membrane This is because two types of optimal solvents that can be applied were selected, and after cosolvent was used, a complex solvent whose ratio was optimized was used.

Accordingly, the polymer electrolyte composite membrane of the present invention includes a silica-based functional polymer and an ion conductive polymer in a weight ratio of 1:3 to 3:1. The content ratio of the silica-based functional polymer and the ion conductive polymer was experimentally determined in consideration of the performance of the polymer electrolyte composite membrane, especially high ion conductivity/high chemical stability.

Here, the silica-based functional polymer is any one or more of D-ASFP (Diol Alkoxysilane-functionalized Polymer), BD-ASFP (bisphenol dimethyl benzanthracene ASFP), BDP-ASFP (Polydimethylsiloxane ASFP), and the structural formulas shown in FIGS. Can have.

As the ion conductive polymer, all known ion conductive polymers that can be used in the polymer electrolyte membrane may be used, but as an embodiment, Nafion, 3M ionomer, sulfonated fluorine polymer, benzimidazole polymer, polyimide polymer , Polyamide polymer, polyarylene ether polymer, polyetherimide polymer, polyphenylene sulfide polymer, polysulfone polymer, polyethersulfone polymer, polyetherketone polymer, polyether-etherketone polymer , Polyphosphazene polymer, polystyrene polymer, radiation-grafted FEP-g-polystyrene, radiation-grafted PVDF-g-polystyrene (radiation-grafted PVDF- g-polystyrene) and polyphenylquinoxaline-based polymer may be any one or more selected from the group consisting of.

In particular, the polymer electrolyte composite membrane of the present invention is formed by being combined with each other after dissolving in a complex solvent composed of a silica-based functional polymer and an ion conductive polymer mixed in a weight ratio of DMAc and NMP in a weight ratio of 1:3 to 3:1. /It is predicted that high chemical stability can be obtained.

In addition, the method for producing a polymer electrolyte composite film of the present invention comprises: preparing a composite solvent; Preparing a membrane precursor solution by adding a silica-based functional polymer and an ion conductive polymer to the complex solvent; Casting the film precursor solution to form a precursor film; Drying the precursor film; And pre-treating the dried precursor film.

Here, the complex solvent may be formed by mixing dimethylacetamide (DMAc) N-Methyl-2-pyrrolidone (NMP) in a weight ratio of 1:3 to 3:1. . As will be described later, the types and mixing ratios of the solvents constituting the composite solvent of the present invention are determined to have an optimum range through a characteristic experiment of the polymer electrolyte composite membrane prepared using the composite solvent. Therefore, the step of preparing the complex solvent may be performed by adding DMAc and NMP to the reaction vessel to have a certain weight ratio. If necessary, further mixing for homogenization may be performed.

The step of preparing the membrane precursor solution may be performed by adding a silane-based functional polymer and an ion conductive polymer in any order to the prepared complex solvent and then stirring at room temperature. At this time, the membrane precursor solution may be prepared to contain a silica-based functional polymer and an ion conductive polymer in a weight ratio of 1:3 to 3:1. As described above, the content ratio of the silica-based functional polymer and the ion conductive polymer is a polymer It was determined experimentally in consideration of the performance of the electrolyte composite membrane, especially high ionic conductivity/high chemical stability.

The step of forming the precursor film may be performed by applying a film precursor solution onto a flat plate such as a glass plate and then forming a thin film with a doctor blade as an embodiment.

The drying step is performed by raising the temperature of the precursor film in a vacuum to a temperature of 70° C. or less, a temperature of 70° C. to 90° C., and a temperature of 100° C. or more, and as an embodiment, after maintaining the precursor film at 60° C. for 8 hours, Treatment at 90° C. for 8 hours and further treatment at 110° C. for 8 hours may be performed.

The pretreatment step is performed to effectively form an ion transport channel by activating hydrophilic groups in the composite film while simultaneously treating contaminants on the surface of the obtained precursor film. As an embodiment, the dried precursor film may be immersed in a basic aqueous solution, treated, and then immersed in distilled water, and then treated by immersing in an acidic aqueous solution, and then immersed in distilled water.In the examples described later, the basic aqueous solution is an acidic solution of hydrogen peroxide. As the aqueous solution, aqueous sulfuric acid solution was used. Here, the immersion treatment may be performed for 0.1 to 2 hours at a temperature range of 20 to 90°C.

Through the above configuration, the polymer electrolyte composite membrane of the present invention exhibits excellent properties, and in particular, high ionic conductivity/high chemical stability can be realized.

Accordingly, the energy storage device and water treatment device such as a redox flow cell or a fuel cell of the present invention can secure stable performance by including a polymer electrolyte composite membrane having high ionic conductivity and high chemical stability.

Example 1

1. Steps to prepare a complex solvent

Complex solvent 1 was prepared by adding DMAc and NMP in a weight ratio of 3:1 to the reaction vessel.

2. Preparing the membrane precursor solution

Based on 2 g of solid content, 75 wt% of PFSA polymer as an ion conductive polymer and 25 wt% of D-ASFP (Diol Alkoxysilane-functionalized Polymer) shown in FIG. 1 as a silane-based functional polymer were added to the complex solvent 1 at room temperature. After stirring for a period of time, a membrane precursor solution was obtained.

3. Step of forming the precursor film

After the film precursor solution was applied on a glass plate, it was formed thinly with a doctor blade to obtain a precursor film.

4. Drying step

The precursor film was placed in a vacuum oven, maintained for 8 hours in the order of 60°C, 90°C, and 110°C, and gradually heated up and treated to obtain a dried precursor film.

5. Pre-treatment steps

After the dried precursor film is immersed in distilled water, 50 ml of 3% hydrogen peroxide, 0.5MH ₂ SO ₄ aqueous solution, and distilled water are each prepared and placed on a plate set at 50°C. Thereafter, 3% hydrogen peroxide, distilled water, 0.5MH ₂ SO ₄ aqueous solution, and distilled water were allowed to stand for 30 minutes each step in order to perform a pretreatment step to obtain a polymer electrolyte composite membrane 1 (D3N1).

Example 2

A polymer electrolyte composite film 2 (D1N1) was obtained in the same manner as in Example 1 except for using the composite solvent 2 prepared by adding DMAc and NMP in a weight ratio of 1:1, not the composite solvent 1.

Example 3

A polymer electrolyte composite film 3 (D1N3) was obtained in the same manner as in Example 1, except for using the composite solvent 3 prepared by adding DMAc and NMP in a weight ratio of 1:3 instead of the composite solvent 1.

Comparative Example 1

PFSA polymer was added to DMAc to prepare a 20wt% PFSA solution, and D-ASFP shown in FIG. 1 as a silica-based functional polymer was added to DMAc to prepare a solution diluted to a concentration of 50wt%, and then an ion conductive polymer based on 2g of solid content. Comparative Example Polymer electrolyte was carried out in the same manner as in Example 1, except that the membrane precursor solution was prepared by mixing in DMAc in a solution phase so as to be 75 wt% and 25 wt% of the silane-based functional polymer and stirred at room temperature for 1 hour. A composite film 1 (DMAc) was obtained.

Comparative Example 2

A comparative example polymer electrolyte composite film 2 (DMF) was obtained by performing the same method as in Comparative Example 1, except that DMF instead of DMAc was used as the solvent.

Comparative Example 3

Comparative Example Polymer Electrolyte Composite Film 3 (NMP) was obtained by performing the same method as in Comparative Example 1, except that NMP instead of DMAc was used as the solvent.

Sample names of the polymer electrolyte composite membranes prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1 below.

Sample name Polymer composition Solvent composition DMAc (Comparative Prepolymer Electrolyte Composite Membrane 1) PFSA+ASFP
(75 wt%: 25 wt%) DMAc DMF (Comparative Preliminary Polymer Electrolyte Composite Membrane 2) DMF NMP (Comparative Preliminary Polymer Electrolyte Composite Membrane 3) NMP D3N1 (Polymer electrolyte composite film 1) DMAc: NMP
(75 wt%: 25 wt%) D1N1 (polymer electrolyte composite film 2) DMAc: NMP
(50 wt%: 50 wt%) D1N3 (polymer electrolyte composite film 3) DMAc: NMP
(25 wt%: 75 wt%)

Experimental Example 1

The moisture content was measured for the polymer electrolyte composite membranes 1 to 3 and the polymer electrolyte composite membranes 1 to 3 obtained in Examples 1 to 3 and Comparative Examples 1 to 3 as follows, and the results are shown in Table 2 below.

In order to measure the water content (Water Uptake) of the polymer electrolyte composite membrane sample, the samples to be measured were dried in an oven at 100° C. under vacuum for 24 hours or more, and then the mass and length/length were measured, and immersed in distilled water for 24 hours or more. Thereafter, moisture on the surface of the polymer electrolyte composite membrane was removed, and the weight and dimensional change at room temperature were measured three times each to derive an average value. In the same manner as the above method, the weight was measured three times at 30°C, 50°C, and 70°C, and the average value was calculated by applying to the following equation.

[Equation 1]

Water Uptake(%) 30℃ 50℃ 70℃ Nafion 212 20.4 32.2 41.2 DMAc 23.0 37.2 48.1 DMF 21.1 33.3 44.3 NMP 22.3 35.2 46.7 D3N1 23.5 36.9 47.9 D1N1 22.9 35.8 47.8 D1N3 22.5 34.7 47.7

The moisture content of the polymer electrolyte composite membrane is greatly influenced by the hydrophilic group, and among them, it is mainly influenced by the sulfonic acid group. As can be seen from the above results, it can be seen that the water content of the polymer electrolyte composite membrane in which the solvent is selected as DMF is the lowest, which, as reported in other documents, has the binding strength of the DMF solvent and the sulfonic acid group (-SO ₃ H) to other solvents. Because it is the strongest compared to

On the other hand, in the case of the polymer electrolyte composite membrane in which the solvent is DMAc, it can be seen that the value is somewhat higher than that of NMP.

Experimental Example 2

The ion exchange capacity was measured for the polymer electrolyte composite membranes 1 to 3 and Comparative Example polymer electrolyte composite membranes 1 to 3 obtained in Examples 1 to 3 and Comparative Examples 1 to 3 as follows, and the results are shown in Table 3 below. Done.

In order to measure the ion exchange capacity of the polymer electrolyte composite membrane for each solvent used at the time of manufacture, samples dried in an oven at 100° C. for more than 24 hours were weighed. Thereafter, a 1M NaOH solution was prepared, 50 ml was aliquoted into a beaker, and the sample was immersed for 24 hours or more. Thereafter, about 5 drops were added dropwise by designating 3wt% of phenolphthalein as an indicator. Then, it was titrated with a 0.1M NaOH solution, and the titrated amount of 0.1M NaOH, the weight of the dried sample measured above, and the number of moles of NaOH were applied to the following equation.

[Equation 2]

Ion Exchange Capacity
(mmol/g) Nafion 212 0.91 DMAc 0.98 DMF 0.80 NMP 0.94 D3N1 0.97 D1N1 0.97 D1N3 0.96

Ion exchange capacity (IEC) is an experiment that quantitatively identifies hydrophilic groups in a polymer membrane sample, and is affected by -COOH, -OH, -SO ₃ H, but is greatly influenced by -SO ₃ H, which has high acidity. Receive.

Compared to the Nafion 212 sample, it can be seen that the IEC is generally higher for other polymer membranes, which is believed to be due to the structure of D-ASFP introduced into the PFSA polymer. As shown in FIG. 1, D-ASFP has a number of -COOH, -OH, -SO ₃ H, and thus it appears that when introduced into a polymer membrane, the ion exchange capacity can be drawn at the level of a commercially available Nafion membrane.

As a result of the ion exchange capacity analysis, it can be seen that the IEC value of DMF is the lowest, and the value of the polymer composite membrane sample in which DMAc is the solvent is higher, as in the moisture content analysis. However, the difference is insignificant when compared to D3N1, D1N1, and D1N3, so it is predicted that a similar trend will also be exhibited in the ionic conductivity results to be analyzed later.

Experimental Example 3

The ionic conductivity of the polymer electrolyte composite membranes 1 to 3 obtained in Examples 1 to 3 and Comparative Examples 1 to 3 and the comparative polymer electrolyte composite membranes 1 to 3 were measured as follows, and the results are shown in Table 4 below. .

To measure the ionic conductivity of the polymer electrolyte composite membrane sample, the thickness and length of the sample were measured, and the resistance value was derived through the 4-probe method of Dupont, and the evaluation was performed at each of 30℃, 50℃, and 70℃. Evaluation was performed. Thereafter, the average value of the derived thickness, vertical length, and resistance was introduced into the following equation.

[Equation 3]

Ion Conductivity (S/cm) 30℃ 50℃ 70℃ Nafion 212 0.081 0.148 0.168 DMAc 0.099 0.159 0.179 DMF 0.079 0.093 0.130 NMP 0.085 0.152 0.170 D3N1 0.090 0.155 0.174 D1N1 0.087 0.154 0.173 D1N3 0.085 0.152 0.171

As a result of the ion conductivity analysis for each temperature, it can be seen that DMAC> D3N1> D1N1> D1N3> NMP> DMF were high in the order, and the tendency was remarkable as the temperature increased.

As mentioned in the IEC analysis, although DMAc shows a slightly high tendency, it can be seen that it has similar ionic conductivity to D3N1 and D1N1. Therefore, it is judged that it can be used as a complex solvent by reducing the content of highly toxic DMAc and mixing NMP together.

Experimental Example 4

The Fenton test was performed on the polymer electrolyte composite membranes 1 to 3 obtained in Examples 1 to 3 and Comparative Examples 1 to 3 and the polymer electrolyte composite membranes 1 to 3 of Comparative Examples as follows, and the results are shown in Table 5 below. .

Fenton Test Before immersion After immersion Weight change rate (%) Nafion 212 0.0903g 0.0870g 3.7 DMAc 0.1086g 0.1022g 5.9 DMF 0.0853g 0.0820g 3.9 NMP 0.0617g 0.0578g 6.3 D3N1 0.1424 0.1340 5.9 D1N1 0.1211 0.1138 6.0 D1N3 0.1139 0.1070 6.1

The Fenton test is an index to evaluate the chemical stability of a polymer membrane, and more specifically, an experiment to evaluate the stability against OH radicals. In a 1L volumetric flask, add 3mg (3 ppm) of FeSO ₄ (Ⅱ) , fill 30% of H ₂ O ₂ to the mark, stir sufficiently, and then add a buffer (Hepes, (4-(2-hydroxyethyl)-1-piperazine ethnaesulfonic). acid; HEPES, or 3-morpholinopropane-1 -sulfonic acid; MOPS) was added to adjust the pH of the solution to about 3.5. Then, the polymer membrane sample was dried at 100°C and then weighed. , About 25 ml of the pH-adjusted solution was aliquoted and the dried polymer membrane sample was immersed in. The immersed sample was left in an oven at 80°C, washed thoroughly with distilled water, dried in an oven at 100°C, and then weighed The stability of OH radicals is evaluated by comparing the weight before immersion and the weight after immersion.

Since OH radicals are very unstable in their structure, they have the property of obtaining electrons by oxidizing other substances to become stable. As reported in many literatures, OH radicals tend to recover stability by attacking amorphous parts such as sulfonic acid groups and carboxyl groups (-COOH) when in contact with PFSA polymers.

As a result of the Fenton test analysis, as shown in Table 5, it can be seen that the weight change rate of the polymer electrolyte composite membrane in which DMF was selected as a solvent was 3.9%, which corresponds to Nafion 212 and has the highest chemical stability. This is because, as mentioned above, the attraction of the DMF solvent and the sulfonic acid group is greater than that of other solvents.

When comparing the attraction of the sulfonic acid group with the DMAc and NMP solvents as reported in various documents, NMP is somewhat higher than that of DMAc, and thus chemical stability should also be high. However, in the above results, the stability of NMP is lower than that of DMAc. This is because the BP of NMP is 202°C, so it is estimated that there are more residual solvents than other solvents DMAc (BP 165°C) and DMF (153°C). Although the binding strength of the NMP and sulfonic acid groups is greater than that of DMAc, the stability of the polymer membrane sample in which NMP is a solvent is estimated to be relatively low because the residual solvent is relatively larger than that of DMAc, creating an environment susceptible to attack in the irregular region.

Through the above experiments, it can be seen that DMAc is an optimal solvent that satisfies the properties of water content, ion exchange capacity, ion conductivity, and high ion conductivity/high chemical durability derived through the Fenton test. However, DMAc is known to deteriorate the health of users due to its toxic properties and adversely affect the environment when discharged.

Therefore, it is considered desirable to make a complex solvent by mixing NMP, which is relatively less toxic than DMAc. In fact, as a result of the evaluation of physical properties and chemical stability, the complex solvents D3N1, D1N1, and D1N3 showed very similar performance to the polymer membrane samples in which DMAc was a solvent, so it is believed that application as a complex solvent will not significantly affect the performance.

In other words, rather than using only DMAc as a solvent, when using a complex solvent composed of mixing DMAc and NMP in a weight ratio of 1:3 to 3:1 as in the present invention, toxicity is reduced during manufacture, improving safety, and reducing expensive solvents. This is because it can be seen from the above experiment that the cost can be reduced because it can be replaced with a more inexpensive solvent, and the performance of the polymer electrolyte composite membrane is equal to or higher while the manufacturing process is simplified and economical is excellent.

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

Claims (7)

A silica-based functional polymer and an ion conductive polymer are included in a weight ratio of 1:3 to 3:1,
The silica-based functional polymer is any one or more of D-ASFP (Diol Alkoxysilane-functionalized Polymer), BD-ASFP (bisphenol dimethylbenzanthracene ASFP), BDP-ASFP (Polydimethylsiloxane ASFP),
The silica-based functional polymer and the ion conductive polymer are dissolved in a complex solvent composed of DMAc and NMP mixed in a weight ratio of 1:3 to 3:1 and bonded to each other.
The method of claim 1,
Ion conductive polymers include Nafion, 3M ionomer, sulfonated fluorine polymer, benzimidazole polymer, polyimide polymer, polyamide polymer, polyarylene ether polymer, polyetherimide polymer, polyphenylene sulphate. Fide-based polymer, polysulfone-based polymer, polyethersulfone-based polymer, polyetherketone-based polymer, polyether-etherketone-based polymer, polyphosphagen-based polymer, polystyrene-based polymer, radiation-grafted FEP-g-polystyrene (radiation-grafted FEP-g-polystyrene), radiation-grafted PVDF-g-polystyrene (radiation-grafted PVDF-g-polystyrene), and polyphenylquinoxaline-based polymer. Polymer electrolyte composite membrane.
Preparing a complex solvent; Preparing a membrane precursor solution by adding a silica-based functional polymer and an ion conductive polymer to the complex solvent; Casting the film precursor solution to form a precursor film; Drying the precursor film; And pre-treating the dried precursor film;
The silica-based functional polymer is any one or more of D-ASFP (Diol Alkoxysilane-functionalized Polymer), BD-ASFP (bisphenol dimethylbenzanthracene ASFP), BDP-ASFP (Polydimethylsiloxane ASFP),
The complex solvent is composed of DMAc and NMP mixed in a weight ratio of 1:3 to 3:1,
The membrane precursor solution contains the silica-based functional polymer and the ion conductive polymer in a weight ratio of 1:3 to 3:1,
The drying step is a method of manufacturing a polymer electrolyte composite film, characterized in that the precursor film is heated to a temperature of 70 ℃ or less, a temperature of 70 ℃ to 90 ℃ and a temperature of 100 ℃ or more in a vacuum state.
The method of claim 3,
The pretreatment step is a method of manufacturing a polymer electrolyte composite membrane, characterized in that the dried precursor film is immersed in a basic aqueous solution, treated, and then immersed in distilled water, and then treated by immersing in an acidic aqueous solution, and then immersed in distilled water.
An energy storage device comprising the polymer electrolyte composite membrane of claim 1 or 2 or the polymer electrolyte composite membrane manufactured by the manufacturing method of claim 3 or 4.
The method of claim 5,
The energy storage device is an energy storage device, characterized in that the redox flow cell or fuel cell.
A water treatment apparatus comprising the polymer electrolyte composite membrane of claim 1 or 2 or the polymer electrolyte composite membrane manufactured by the manufacturing method of claim 3 or 4.

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