KR20120041645A - Ion conductive composite membrane, preparation method thereof, membrane-electrode assembly and fuel cell comprising the same - Google Patents

Abstract

PURPOSE: An ion-conductive composite layer is provided to have excellent durability, dimensional stability, and electrochemical properties, thereby remarkably improving the performance of a membrane-electrode assembly and a fuel cell. CONSTITUTION: An ion-conductive composite layer comprises crosslinked polyvinylalcohol and a polystyrene sulfonic acid/maleic acid copolymer coating layer(4) on at least one side of a porous non-ionic conductive polymer layer. A manufacturing method of the ion conductive composite film comprises: a step of manufacturing a porous non-ion conductive polymer membrane; a step of manufacturing coating solution by mixing polyvinylalcohol, polystyrene, a sulfonic acid/maleic acid copolymer, and a solvent; a step of coating at least one side of the porous polymer with the coating solution; and a step of thermal crosslinking the coated polymer membrane at 100-160 °C for 30 minutes - 5 hours.

Description

Ionic conductive composite membrane, preparation method thereof, membrane-electrode assembly and fuel cell

The present invention relates to an ion conductive composite membrane, a method for manufacturing the same, a membrane-electrode assembly and a fuel cell comprising the same, an ion conductive composite membrane having excellent dimensional stability, durability and electrochemical properties, a method for manufacturing the same, and a membrane comprising the same It relates to an electrode assembly and a fuel cell.

The direct methanol fuel cell (DMFC) has a structure and principle of operation similar to that of a polymer electrolyte membrane fuel cell (PEMFC) that uses hydrogen. ) To be used.

Therefore, the fuel supply system is simple and the whole apparatus is simple, which makes it possible to miniaturize. The direct methanol fuel cell can be used for various purposes. Especially, it is very likely to be used as a power source for replacing a small battery of about 1W or a portable power supply of less than 500W. will be.

The problems in the commercialization of the direct methanol fuel cell are that the power density is lower than that of the conventional fuel cell system due to the catalyst poisoning phenomenon, and the conventional Nafion used in the membrane-electrode assembly (MEA). Polymer electrolyte membranes are not optimized for direct methanol fuel cells, and commercially available economical polymer electrolyte membranes have not been developed worldwide.

In addition, a major problem in using a conventional polymer electrolyte membrane directly in a methanol fuel cell is that methanol, which is a fuel, penetrates the polymer electrolyte membrane from the cathode to the anode in a significant amount to cause interaction with the anode electrode. Due to this interaction, the anode potential decreases and battery voltage is lost. That is, a large area of research for improving the performance of direct methanol fuel cell is in the polymer electrolyte membrane, and the development of materials capable of minimizing the influence on methanol crossover and obtaining high ion conductivity is required.

Accordingly, the present inventor has proposed a polymer electrolyte membrane comprising polyvinyl alcohol (polyvinylalcohol, PVA) known as a methanol resistor in a dialysis evaporation process, and a polystyrene sulfonic acid / maleic acid copolymer capable of bringing about an increase in ionic conductivity as a crosslinking agent. However, when the content of the polystyrene sulfonic acid / maleic acid copolymer is high, the membrane tends to be easily broken, and thus there is a problem that the durability is poor and the ion conductivity is difficult to be improved.

In order to improve the above problems, an object of the present invention is a polyvinyl alcohol (polyvinylalcohol, PVA) and a crosslinking agent and a polystyrene sulfonic acid / maleic acid copolymer which can bring an increase in ionic conductivity on the surface of the porous non-ionic polymer membrane having excellent durability It is to provide an ion conductive composite membrane and a method of manufacturing the same to form a polymer layer to have excellent electrochemical properties and durability.

Another object of the present invention is to provide a membrane-electrode assembly and a fuel cell including such an ion conductive composite membrane.

To this end, the present invention,

Provided is an ion conductive composite membrane having a polyvinyl alcohol crosslinked and a polystyrene sulfonic acid / maleic acid copolymer coating layer formed on at least one surface of a porous nonionic conductive polymer membrane.

Also,

Preparing a porous nonionic conductive polymer membrane;

Preparing a coating solution by mixing a polyvinyl alcohol, a polystyrene sulfonic acid / maleic acid copolymer, and a solvent;

Coating at least one surface of the porous polymer membrane with the coating solution; And

It provides an ion conductive composite membrane manufacturing method comprising the step of thermally cross-linking the coated polymer membrane at 100 ~ 160 ℃ for 30 minutes to 5 hours.

Also,

The ion conductive composite membrane; And

Provided is a fuel cell membrane-electrode assembly including an anode electrode and a cathode electrode which face each other with the ion conductive composite membrane interposed therebetween.

In another aspect, the present invention provides a fuel cell comprising the membrane electrode assembly.

The ion conductive composite membrane of the present invention exhibits excellent durability, dimensional stability and electrochemical characteristics, and can greatly improve the performance of the membrane-electrode assembly and the fuel cell including the same.

1 is a perspective view showing a composite membrane according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, the present invention is not necessarily limited to those illustrated in the drawings, and the thicknesses are enlarged to clearly express various parts and regions.

1 is a cross-sectional view showing a composite film according to an embodiment of the present invention.

Referring to the drawings, the composite membrane 10 according to an embodiment of the present invention is a medium used to transfer hydrogen ions generated from the anode electrode of the fuel cell to the cathode, and is crosslinked on at least one surface of the porous non-ionic conductive polymer membrane. Polyvinyl alcohol and polystyrene sulfonic acid / maleic acid copolymer coating layer are formed.

The polymer membrane 2 is made of a nonionic conductive polymer, and may be used without limitation as long as it can serve as a porous substrate that provides an ion conducting channel for mechanical strength and migration of hydrogen ions. Typically, a polymer film made of polyethylene, polypropylene, or polytetrafluoroethylene can be used.

The porosity of the porous nonionic conductive polymer membrane 2 is preferably 50 to 90%. In this case, when the porosity exceeds the above range, there is a problem in that the mechanical strength is insufficient and it is difficult to act as a support. On the contrary, when the porosity is below the above range, there is a problem that the ion is not sufficiently moved due to the lack of a hydrogen ion conducting channel.

The polymer membrane 2 may not only secure mechanical strength and durability, but may also secure hydrogen ion conductivity by forming a coating layer 4 on the surface thereof.

The coating layer (4) comprises a cross-linked polyvinyl alcohol and polystyrene sulfonic acid / maleic acid copolymer coating layer. The polyvinyl alcohol is formed on the surface of the polymer film 2 as a methanol resistor to reduce the methanol permeability of the composite film 10. The polystyrene sulfonic acid / maleic acid copolymer not only acts as a crosslinking agent, but can also lead to an increase in ionic conductivity through sulfonic acid groups.

As such, the composite membrane 10 according to the present invention is applied to the polystyrene sulfonic acid / maleic acid copolymer through the coating layer, it is possible to improve the weak durability that occurs when manufacturing the membrane using this.

At this time, the coating layer (4) is added to tri- trihydroxysilyl-1-propane sulfonic acid (3- (trihydroxysilyl) -1-propane-sulfonic acid) in addition to improve the ionic conductivity as well as inhibit methanol permeation due to hydrophobic groups. It is preferable to include.

As described above, the composite membrane according to the present invention is formed of a cross-linked polyvinyl alcohol and polystyrene sulfonic acid / maleic acid copolymer coating layer on a porous non-ionic conductive polymer membrane having an appropriate mechanical strength and durability, thereby providing excellent electrical conductivity and the like. Since the chemical properties are exhibited, the performance of the membrane-electrode assembly and the fuel cell including the same can be greatly improved.

Such a composite membrane of the present invention,

Preparing a porous nonionic conductive polymer membrane;

Preparing a coating solution by mixing a polyvinyl alcohol, a polystyrene sulfonic acid / maleic acid copolymer, and a solvent;

Coating at least one surface of the porous polymer membrane with the coating solution; And

The coated polymer film is prepared through thermal crosslinking at 100 to 160 ° C. for 30 minutes to 5 hours.

Each step will be described in more detail below.

First, a porous nonionic conductive polymer membrane is prepared.

The thickness of the polymer membrane is preferably in the range of 10 to 30 ㎛ in consideration of mechanical properties and ion conductivity resistance. The material of the porous nonionic conductive polymer membrane is as described above.

Subsequently, a coating solution is prepared by mixing the polyvinyl alcohol, polystyrene sulfonic acid / maleic acid copolymer, and a solvent.

The coating solution may further include 3-trihydroxysilyl-1-propane sulfonic acid to improve ion conductivity.

The solvent is not particularly limited as long as the polyvinyl alcohol, polystyrene sulfonic acid / maleic acid copolymer and 3-trihydroxysilyl-1-propane sulfonic acid can be uniformly dissolved and dispersed. Preferably, polyvinyl alcohol is dissolved in dimethyl sulfoxide, polystyrene sulfonic acid / maleic acid copolymer, and 3-trihydroxysilyl-1-propane sulfonic acid are used after mixing in water.

At this time, the coating solution is 6 to 10% by weight of polyvinyl alcohol; 0.5 to 3 weight percent polystyrene sulfonic acid / maleic acid copolymer; 0.1 to 3 weight percent of 3-trihydroxysilyl-1-propane sulfonic acid; It is preferred to include 55 to 85% by weight of dimethyl sulfoxide and the balance of water.

If the content of each component is less than the lower limit, the uniformity of the coating is reduced and the performance of the membrane is not constant. If the upper limit is exceeded, pores on the surface of the polymer membrane are blocked, and thus the performance of the membrane is reduced.

Next, at least one surface of the porous polymer membrane is coated with the coating solution.

As a method of coating the coating solution on the polymer film, dip coating, bar coating, spray coating, flow coating, solution casting, and the like, which are commonly used, may be used. Preferably solution casting is performed.

In order to uniformly form the coating layer on the surface of the polymer film, the polymer concentration of the coating solution and the coating time may be appropriately adjusted within the above range.

Subsequently, the coated polymer film is thermally crosslinked at 100 to 160 ° C. for 30 minutes to 5 hours.

Through such thermal crosslinking, the polystyrene sulfonic acid / maleic acid copolymer acts as a crosslinking agent to crosslink the polymer in the coating layer, thereby further improving the stability of the coating layer.

In this case, if the thermal crosslinking temperature and time are less than the range, an efficient thermal crosslinking reaction effect may not be obtained. On the contrary, if the thermal crosslinking temperature and time are exceeded, a problem may occur in the thermal stability of the composite membrane.

According to the method of the present invention, it is possible to significantly improve the dimensional stability and durability of the ion conductive composite membrane through a relatively simple process.

The membrane-electrode assembly of the present invention comprises the above ion conductive composite membrane. The membrane electrode assembly of the present invention is the ion conductive composite membrane; And an anode electrode and a cathode electrode which face each other with the ion conductive composite membrane interposed therebetween.

The details of the anode electrode, the cathode electrode, the gas diffusion layer, and the catalyst layer constituting the membrane-electrode assembly are well known in the art and thus, detailed description thereof will be omitted.

The ion conductive composite membrane and the membrane-electrode assembly of the present invention can be effectively used in a polymer electrolyte fuel cell and a direct liquid fuel cell using an electrolyte membrane. Preferably it can be used in a direct methanol fuel cell using methanol as a fuel.

Accordingly, the present invention also provides a fuel cell comprising the membrane-electrode assembly of the present invention.

Example

Hereinafter, preferred embodiments of the present invention are described. The following examples are described for the purpose of more clearly expressing the present invention, but the contents of the present invention are not limited to the following examples.

Example  1 to 6

Polyvinyl alcohol (average molecular weight 89,000 g / mol), polystyrene sulfonic acid / maleic acid copolymer (average molecular weight 20,000 g / mol) and 3-trihydroxysilyl-1-propane sulfonic acid according to the content described in Table 1 Was prepared.

A coating solution was prepared by mixing a solution of polyvinyl alcohol in dimethyl sulfoxide, a solution of polystyrene sulfonic acid / maleic acid copolymer, and 3-trihydroxysilyl-1-propane sulfonic acid in water.

The coating solution was cast on a polyethylene membrane, dried at room temperature for 24 hours to remove the solvent, and crosslinked at 110 ° C. for 2 hours in an oven.

division
Coating solution (content: wt%)
Polyvinyl alcohol Polystyrene Sulfonic Acid / Maleic Acid Copolymer  3-trihydroxy silyl-1-propane sulfonic acid Dimethyl sulfoxide water Example 1
9 One 0 81 9 Example 2
8 2 0 72 18 Example 3
7.5 2.5 0 67.5 22.5 Example 4
8.6 One 0.4 77.4 12.6 Example 5
7.9 0.9 1.2 71.1 18.9 Example 6
7.1 0.8 2.1 63.9 26.1

Example  7 to 13

Polyvinyl alcohol (average molecular weight 89,000 g / mol), polystyrene sulfonic acid / maleic acid copolymer (average molecular weight 20,000 g / mol) and 3-trihydroxy silyl-1-propane sulfonic acid according to the content shown in Table 2 below Was prepared.

A coating solution was prepared by mixing a solution of polyvinyl alcohol in dimethyl sulfoxide, a solution of polystyrene sulfonic acid / maleic acid copolymer, and 3-trihydroxysilyl-1-propane sulfonic acid in water.

The coating solution was cast on a polypropylene membrane, dried at room temperature for 24 hours to remove the solvent, and then crosslinked at 120 ° C. for 30 minutes in an oven.

division
Coating solution (content: wt%)
Polyvinyl alcohol Polystyrene Sulfonic Acid / Maleic Acid Copolymer  3-trihydroxysilyl-1-propane sulfonic acid Dimethyl sulfoxide water Example 7
9 One 0 81 9 Example 8
8 2 0 72 18 Example 9
7.5 2.5 0 67.5 22.5 Example 10
7.7 1.9 0.4 69.3 20.7 Example 11
7.1 1.8 1.1 63.9 26.1 Example 12
6.5 1.6 1.9 58.5 31.5

Example  13 to 18

Polyvinyl alcohol (average molecular weight 89,000 g / mol), polystyrene sulfonic acid / maleic acid copolymer (average molecular weight 20,000 g / mol) and 3-trihydroxysilyl-1-propane sulfonic acid according to the content shown in Table 3 below Sulfonic acid was prepared.

A coating solution was prepared by mixing a solution of polyvinyl alcohol in dimethyl sulfoxide, a solution of polystyrene sulfonic acid / maleic acid copolymer, and 3-trihydroxysilyl-1-propane sulfonic acid in water.

The coating solution was cast on a polyterafluoroethylene membrane, dried at room temperature for 24 hours to remove the solvent, and then crosslinked at 140 ° C. for 90 minutes in an oven.

division
Coating solution (content: wt%)
Polyvinyl alcohol Polystyrene Sulfonic Acid / Maleic Acid Copolymer  3-trihydroxy silyl-1-propane sulfonic acid Dimethyl sulfoxide water Example 13
9 One 0 81 9 Example 14
8 2 0 72 18 Example 15
7.5 2.5 0 67.5 22.5 Example 16
7.2 2.4 0.4 64.8 25.2 Example 17
6.7 2.3 One 60.3 39.7 Example 18
6.2 2 1.8 55.8 34.2

Comparative Example 1

A casting solution was prepared by dissolving 10 g of polyvinyl alcohol (average molecular weight 89,000 g / mol) and 0.7 g of polystyrene sulfonic acid / maleic acid copolymer (average molecular weight 20,000 g / mol) in 0.0893 L of water. The prepared solution was sufficiently stirred to prepare a homogeneous solution, which was cast on a glass plate using a Gardner knife. After drying at room temperature for one day, the formed membrane was separated from the glass plate and crosslinked at 130 ° C. for 90 minutes using a constant temperature dryer to prepare a membrane having a thickness of 60 μm.

Comparative example  2

10 g of polyvinyl alcohol (average molecular weight 89,000 g / mol), 0.7 g of polystyrene sulfonic acid / maleic acid copolymer (average molecular weight 20,000 g / mol), 0.3 g of 3-trihydroxysilyl-1-propane sulfonic acid It was dissolved in 0.089 L to prepare a casting solution. The prepared solution was sufficiently stirred to prepare a homogeneous solution, which was cast on a glass plate using a gardener knife. After drying at room temperature for one day, the formed membrane was separated from the glass plate and crosslinked at 130 ° C. for 90 minutes using a constant temperature dryer to prepare a membrane having a thickness of 60 μm.

Experimental Example  1: moisture content and swelling

In order to confirm the dimensional safety of the composite membrane prepared in Examples 1 to 18, the water content and the swelling ratio for water were measured.

A sample membrane having a size of 5 cm × 5 cm was prepared and immersed in 25 ° C. ultrapure water for 24 hours or more, and then removed from the glass moisture adhered to the surface by a filter paper. Next, the water was put in a vacuum oven to remove moisture, and the dried film was placed in an airtight container and weighed.

The water content was calculated as (weight of membrane after swelling-weight of membrane before swelling) / (weight of membrane before swelling) X100 and swelling degree was calculated as (membrane area after swelling-membrane area before swelling) / (membrane area before swelling) X100. The results are shown in Table 4 below.

division Moisture content (%) Swelling degree (%) Example 1 20.5 110.8 Example 2 11.7 109.2 Example 3 7.5 108.9 Example 4 20 108.4 Example 5 10.8 106.2 Example 6 6.3 103.9 Example 7 31.5 117.6 Example 8 21.8 114.1 Example 9 20.9 109.6 Example 10 30.6 112.4 Example 11 19.6 109.3 Example 12 15.4 107.7 Example 13 17.4 108.7 Example 14 16.9 108.2 Example 15 14.8 107.3 Example 16 13.3 105.2 Example 17 12.0 105.4 Example 18 8.2 102.7 Nafion 115 19 113.4 Comparative Example 1 150 175 Comparative Example 2 175 173.3

As shown in Table 4, as the content of the polystyrene sulfonic acid / maleic acid copolymer and 3-trihydroxysilyl-1-propane sulfonic acid in the coating aqueous solution increased, both the water content and the swelling degree of the membrane decreased. This is because the free volume in the membrane is reduced due to the increase in the polystyrene sulfonic acid / maleic acid copolymer and 3-trihydroxy 1-propane sulfonic acid particles, thereby decreasing the water content. As such, the low water content means that the swelling effect is small, which means that penetration into the electrolyte membrane is difficult but selective is advantageous for permeation.

Experimental Example  2: Ion exchange capacity measurement

In order to measure the ion exchange capacity, the ion exchange capacity was determined by an acid salt titration using 1N NaOH aqueous solution and 1N HCl aqueous solution by the following equation. The prepared sample membrane was cut to an appropriate size, weighed, and deposited in 100 ml of 0.1N NaOH aqueous solution for at least one day. Thereafter, NaOH reduction was measured by titration with 0.1 N HCl. The results are shown in Table 5 below.

Ion exchange capacity IEC (meq / g) = {(VHCl × NHCl) -5 (VNaOH × NNaOH)} / sample film weight (g)

Volume of VHCl: HCl (ml), VNaOH: volume of NaOH (ml)

NHCl: concentration of HCl (N), NNaOH: concentration of NaOH (N)

division Ion exchange capacity (meq / g)
Example 1 0.652 Example 2 0.712 Example 3 0.732 Example 4 0.684 Example 5 0.744 Example 6 0.763 Example 7 0.61 Example 8 0.66 Example 9 0.70 Example 10 0.662 Example 11 0.745 Example 12 0.75 Example 13 0.54 Example 14 0.624 Example 15 0.696 Example 16 0.62 Example 17 0.724 Example 18 0.745 Nafion 115 0.91 Comparative Example 1 0.88 Comparative Example 2 1.04

Referring to Table 5, as the content of the polystyrene sulfonic acid / maleic acid copolymer and 3-trihydroxysilyl-1-propane sulfonic acid increased in the coating solution, the ion exchange capacity of the composite membrane increased.

Experimental Example  3: Methanol Permeability Measurement

The methanol permeability of Example 3 prepared above was measured by a two chamber diffusion cell method. One chamber (250 mL) was filled with 2 M methanol solution and the other chamber (34 mL) was filled with ultrapure water for measurement. The effective area of the membrane located between the two chambers was 7.02 cm ² and was kept airtight using clamps. The experiment was stirred and a thermocouple was used for temperature measurement. After a certain period of time, when methanol diffused from the chamber filled with the methanol solution toward the chamber filled with ultrapure water through the polymer electrolyte, the amount of methanol diffused was measured by gas chromatography. Table 6 below shows the methanol concentration measured at 55 ° C., and Table 7 shows the methanol permeability of each sample membrane at 25 ° C.

Time (minutes) GC Methanol Concentration Actual methanol concentration 0 0 0 30 0 0 60 0 0 90 0.8807 0.894838447 120 1.0494 1.066246698 2M methanol 6.1834 6.282666125

division Methanol Permeability (cm ² / s) Example 3 - Comparative Example 1 1.19 × 10 ^-6 Comparative Example 2 4.12 × 10 ^-7

As shown in Table 6 and Table 7, the composite membrane of Example 3 according to the present invention showed that the methanol content was less than measurable as measured by methanol at 25 ° C., and methanol permeability at 55 ° C. was 5.4 ×. 10 ^-5 cm ² / s. This result is significantly lower than 2.11 × 10 ⁶ cm ² / s at 25 ° C of Nafion 115, which is currently used in direct methanol fuel cells. This low methanol permeability increases the hydrogen bond between the hydroxyl group of polyvinyl alcohol and the functional group of the polystyrene sulfonic acid / maleic acid copolymer as the content of the polystyrene sulfonic acid / maleic acid copolymer in the coating solution increases, thereby reducing the free volume. As a result, the migration of water molecules is reduced, and the hydrophobic porous membrane is thought to be due to the barrier action to methanol.

Experimental Example  4: ion conductivity measurement

Hydrogen ion conductivity was measured according to the equation of σ = l / (R × S) by measuring ohmic resistance or bulk resistance using a Four Point probe AC impedance spectroscopic method.

Where σ (S / cm) is the hydrogen ion conductivity, l (cm) is the distance between the voltage drop measurement electrodes, R (Ω) is the ohmic resistance of the polymer electrolyte, and S is the area in the electrolyte through which a constant current passes (cm ² ). Means. The results are shown in Table 8 below.

division Ion Conductivity (scm ^-1 )
25 ℃ 40 ℃ 55 ℃ 70 ℃ Example 1 0.00106 0.00160 0.00205 0.00343 Example 2 0.00635 0.00964 0.0119 0.0104 Example 3 0.00873 0.01322 0.01841 0.01926 Example 4 0.0062 0.0123 0.0173 0.053 Example 5 0.0143 0.043 0.097 0.147 Example 6 0.018 0.09 0.127 0.176 Example 7 0.001 0.00162 0.002 0.00326 Example 8 0.006 0.00847 0.0108 0.0120 Example 9 0.00724 0.0121 0.01671 0.018 Example 10 0.0059 0.0114 0.016 0.049 Example 11 0.0126 0.044 0.096 0.138 Example 12 0.020 0.094 0.132 0.181 Example 13 0.0009 0.00142 0.00192 0.0028 Example 14 0.0052 0.00802 0.0093 0.0101 Example 15 0.006 0.0117 0.01423 0.0164 Example 16 0.0041 0.0108 0.0154 0.04 Example 17 0.0107 0.032 0.077 0.129 Example 18 0.0163 0.082 0.10 0.154 Nafion 115 0.091 0.087 0.083 00.074 Comparative Example 1 0.010 - - - Comparative Example 2 0.023 - - -

As shown in Table 8, as the content of polystyrene sulfonic acid / maleic acid copolymer in the coating solution and the measurement temperature increases, the ion conductivity showed a tendency to increase. The ionic conductivity of Nafion 115 tended to decrease slightly with increasing temperature, while the composite membrane of polyvinyl alcohol-polystyrene sulfonic acid / maleic acid copolymer-3-trihydroxysilyl-1-propane sulfonic acid was formed. As the temperature increased, the ion conductivity increased. This suggests that the compact portion of the porous polymer membrane inhibits the movement of ions at room temperature, but the ion conductivity of the composite membrane showed better ion conductivity than that of Nafion 115 as these portions became loose due to the increase of temperature.

Experimental Example  5: imprint Modulus  Measure

As an experiment for measuring the mechanical properties of the membrane, the tensile modulus of the membrane was measured using a stretching machine (Universal testing machine: UTM, Llody). Dumbbell-shaped specimens were made and measured by applying a speed of 5 mm / min with a 100 N load cell using a jig of rubber surface. The results are shown in Table 9 below.

division Tensile Modulus (Mpa) Example 1 465.2 Example 2 470.2 Example 3 554.1 Example 4 1027.0 Example 5 906.9 Example 6 846.1 Example 7 327.0 Example 8 415.4 Example 9 486.2 Example 10 782.1 Example 11 624.3 Example 12 611.4 Example 13 512.7 Example 14 523.0 Example 15 549.3 Example 16 1013.2 Example 17 901.4 Example 18 861.2 Nafion 115 350 Comparative Example 1 278 Comparative Example 2 347

As can be seen in Table 9, the composite membrane according to the present invention is Comparative Example 1 consisting of a polyvinyl alcohol / polystyrene sulfonic acid / maleic acid copolymer and polyvinyl alcohol / polystyrene sulfonic acid / maleic acid copolymer / 3-trihydroxy Excellent mechanical strength was shown compared to the membrane of Comparative Example 2 consisting of silyl-1-propane sulfonic acid.

2: porous nonionic conductive polymer membrane
4: coating layer
10: composite membrane

Claims (9)

An ion conductive composite membrane having a coating layer formed of a polyvinyl alcohol crosslinked on at least one surface of a porous nonionic conductive polymer membrane and a polystyrene sulfonic acid / maleic acid copolymer. The method of claim 1, wherein the polymer membrane
Composite membrane comprising one material selected from the group consisting of polyethylene, polypropylene, and polytetrafluoroethylene. The method of claim 1, wherein the coating layer
The composite membrane further comprises 3-trihydroxysilyl-1-propane sulfonic acid. Preparing a porous nonionic conductive polymer membrane;
Preparing a coating solution by mixing a polyvinyl alcohol, a polystyrene sulfonic acid / maleic acid copolymer, and a solvent;
Coating at least one surface of the porous polymer membrane with the coating solution; And
Ion conductive composite membrane manufacturing method comprising the step of thermally cross-linking the coated polymer membrane at 100 ~ 160 ℃ for 30 minutes to 5 hours. The method of claim 4, wherein the coating solution
Further comprising 3-trihydroxysilyl-1-propane sulfonic acid. The method of claim 5, wherein the coating solution
6 to 10 weight percent polyvinyl alcohol; 0.5 to 3 weight percent polystyrene sulfonic acid / maleic acid copolymer; 0.1 to 3 weight percent of 3-trihydroxysilyl-1-propane sulfonic acid; 55 to 85% by weight of dimethyl sulfoxide and the balance of water. The ion conductive composite membrane according to claim 1; And
A membrane-electrode assembly for a fuel cell comprising an anode electrode and a cathode electrode which are opposed to each other with the ion conductive composite membrane interposed therebetween. A fuel cell comprising the membrane-electrode assembly according to claim 7. The fuel cell of claim 8, wherein the fuel cell is a direct methanol fuel cell.

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