KR20170074545A - Multi-block polymer, electrolyte membrane comprising the same and fuel cell comprising the same - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a multi-block polymer, an electrolyte membrane including the same, and a fuel cell including the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a multi-block polymer, an electrolyte membrane including the same, and a fuel cell including the multi-

TECHNICAL FIELD The present invention relates to a multi-block polymer, an electrolyte membrane including the same, and a fuel cell including the same.

Fuel cells are energy conversion devices that convert the chemical energy of a fuel directly into electrical energy. That is, a fuel cell uses a fuel gas and an oxidizing agent, and generates electricity using electrons generated during the oxidation-reduction reaction. The membrane electrode assembly (MEA) of a fuel cell is composed of a cathode, an anode, and an electrolyte membrane, that is, an ion conductive electrolyte membrane, as a portion where an electrochemical reaction of hydrogen and oxygen takes place.

Fuel cells are being developed as a next-generation energy source due to their high energy efficiency and eco-friendly characteristics with low emission of pollutants.

The most important components in the fuel cell are cation exchange polymer electrolyte membranes, which are: 1) excellent proton conductivity, 2) cross-over prevention of electrolyte, 3) strong chemical resistance, 4) 4) It is preferable to have a characteristic of low swelling ratio. The polymer electrolyte membrane is classified into a fluorine system, a partial fluorine system, and a hydrocarbon system. In the case of a partially fluorinated polymer electrolyte membrane, the polymer electrolyte membrane has an excellent physical and chemical stability and a high thermal stability due to its fluorine main chain. Also, like the fluorinated polymer electrolyte membrane, the partial fluorinated polymer electrolyte membrane has the advantages of the hydrocarbon-based polymer electrolyte membrane and the fluorinated polymer electrolyte membrane because the cation-transfer functional group is attached to the end of the fluorinated chain.

However, the partial fluorine-based polymer electrolyte membrane has a problem that the cation transfer function is relatively low because the fine phase separation of the cation-transfer functional groups and the control of aggregation phenomenon are not effectively performed. Therefore, studies have been made to secure a high cation conductivity by controlling the distribution of sulfonic acid groups and the separation of fine phases.

Korean Patent Publication No. 2003-0076057

The present specification is intended to provide a multi-block polymer, an electrolyte membrane including the multi-block polymer, and a fuel cell including the same.

One embodiment of the present disclosure relates to a composition comprising: a first unit; A second unit represented by the following formula (2); And a third unit represented by the following formula (3) and a hydrophobic block:

 [Chemical Formula 1]

(2)

(3)

In the general formulas (1) to (3), R1 to R5 are the same or different from each other and each independently represents hydrogen; heavy hydrogen; A halogen group; Cyano; A substituted or unsubstituted alkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group, M is a Group 1 element, a to c are each an integer of 0 to 3, a 'to c' are each an integer of 1 to 4, d and e are And f is 0 or 1, and when a to e and a 'to c' are two or more, the substituents in the parentheses are the same or different from each other, a + a'≤4, b + b'≤ 4, and c + c'4.

In addition, one embodiment of the present disclosure provides an electrolyte membrane comprising the multi-block polymer.

One embodiment of the present disclosure relates to an anode; Cathode; And an electrolyte membrane provided between the anode and the cathode.

One embodiment of the present disclosure relates to a stack comprising at least two membrane-electrode assemblies according to the above and a bipolar plate provided between the membrane-electrode assemblies; A fuel supply unit for supplying fuel to the stack; And an oxidant supplier for supplying an oxidant to the stack.

The hydrocarbon-based multi-block polymer according to an embodiment of the present invention may be prepared by applying a monomer having another structure having no sulfonic acid group to two types of monomers having other sulfonic acid groups in the hydrophilic block polymerization, Polymerized to have a molecular weight of a certain level or higher. Through this, it is possible to manufacture an electrolyte membrane having good mechanical properties, and the ionic conductivity of the hydrocarbon-based multi-block polymer having such a structure is improved in a low humidified state.

1 is a graph comparing the ionic conductivities of the electrolyte membranes prepared in Examples 1 to 3 and Comparative Example 2 according to one embodiment of the present invention.
2 is a schematic diagram showing the electricity generation principle of the fuel cell.
3 is a schematic view showing one embodiment of a fuel cell.

Hereinafter, the present specification will be described in more detail.

Whenever a component is referred to as "comprising ", it is to be understood that the component may include other components as well, without departing from the scope of the present invention.

The term "substituted" means that the hydrogen atom bonded to the carbon atom of the compound is replaced with another substituent, and the substituted position is not limited as long as the substituent is a substitutable position, , Two or more substituents may be the same as or different from each other.

As used herein, the term " substituted or unsubstituted " A halogen group; A hydroxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryl group; And a substituted or unsubstituted heterocyclic group, or that at least two of the substituents exemplified above are substituted with a substituted substituent.

In the present specification, the halogen group may be fluorine, chlorine, bromine or iodine.

In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 30. Specific examples include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec- N-pentyl, 3-dimethylbutyl, 2-ethylbutyl, heptyl, n-hexyl, Cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethyl Heptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl and the like.

In the present specification, the cycloalkyl group is not particularly limited, but is preferably a group having 3 to 30 carbon atoms. Specific examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, But are not limited to, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert- butylcyclohexyl, cycloheptyl, Do not.

In the present specification, the alkoxy group may be linear, branched or cyclic. The number of carbon atoms of the alkoxy group is not particularly limited, but is preferably 1 to 30 carbon atoms. Specific examples include methoxy, ethoxy, n-propoxy, isopropoxy, i-propyloxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentyloxy, neopentyloxy, N-hexyloxy, n-hexyloxy, 3,3-dimethylbutyloxy, 2-ethylbutyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, benzyloxy, But is not limited thereto.

In the present specification, the aryl group may be a monocyclic or polycyclic aryl group.

When the aryl group is an aryl group, the number of carbon atoms is not particularly limited, but is preferably 6 to 30 carbon atoms. Specific examples of the monocyclic aryl group include a phenyl group, a biphenyl group, a terphenyl group, and the like, but are not limited thereto.

When the aryl group is a polycyclic aryl group, the number of carbon atoms is not particularly limited. And preferably 10 to 30 carbon atoms. Specific examples of the polycyclic aryl group include naphthyl, anthracenyl, phenanthryl, pyrenyl, perylenyl, klychenyl, fluorenyl, and the like.

In the present specification, the fluorenyl group may be substituted, and adjacent substituents may be bonded to each other to form a ring.

,

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등이 될 수 있다. 다만, 이에 한정되는 것은 아니다.When the fluorenyl group is substituted,

,

,

And

And the like. However, the present invention is not limited thereto.

In the present specification, the heterocyclic group in the present specification includes one or more atoms other than carbon, a hetero atom, and specifically, the hetero atom preferably represents an atom selected from the group consisting of O, N, Se and S, . The number of carbon atoms is not particularly limited, but is preferably 2 to 30 carbon atoms. Examples of the heterocyclic group include a thiophene group, a furane group, a furyl group, an imidazole group, a thiazole group, an oxazole group, an oxadiazole group, a triazole group, a pyridyl group, a bipyridyl group, a pyrimidyl group, A pyridazinyl group, a pyrazinopyrazinyl group, an isoquinoline group, an isoquinolinyl group, an isoquinolinyl group, an isoquinolinyl group, an isoquinolinyl group, an isoquinolyl group, A benzothiazole group, a benzothiazole group, a benzothiophene group, a dibenzothiophene group, a benzofuranyl group, a phenanthroline group, a thiazolyl group, a thiazolyl group, An isoxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a benzothiazolyl group, a phenothiazinyl group, and a dibenzofuranyl group, but is not limited thereto.

In the present specification, the heterocyclic group may be monocyclic or polycyclic, and may be an aromatic, aliphatic or aromatic and aliphatic condensed ring, and examples thereof may be selected from the above heteroaryl groups.

In the present specification, an arylene group means a divalent group having two bonding positions in an aryl group. The description of the aryl group described above can be applied except that each of these is 2 groups.

In the present specification, the term "derived" means that the bond of the compound is broken or a new bond is formed as the substituent is released, and the unit derived from the compound may mean a unit connected to the main chain of the polymer. The unit may be included in the main chain in the polymer to constitute the polymer.

As used herein, the term " monomers " refers to a structure in which monomers are included in a polymer, and the monomers are bonded in the polymer by polymerization.

In one embodiment of the present invention, the first unit body and the second unit body means a unit having a sulfonic acid group.

In one embodiment of the present invention, the third unit unit means a unit having no sulfonic acid group.

In one embodiment of the present disclosure, M is sodium or potassium.

In one embodiment of the present disclosure, R 1 to R 3 are hydrogen.

In one embodiment of the present specification, R < 4 > is hydrogen or cyano group.

In one embodiment of the present disclosure, R5 is hydrogen.

In one embodiment of the present disclosure, a + a'4.

In one embodiment of the present disclosure, b + b'4.

In one embodiment of the present disclosure, c + c'4.

In one embodiment of the present invention, Formula (1) is represented by Formula (A), and Formula (2) is represented by Formula (B).

(A)

[Chemical Formula B]

In one embodiment of the present disclosure, Formulas A and B are units derived from potassium hydroquinone sulfonate and sodium 5,5'-sulfonylbis (2-fluorobenzenesulfonate), respectively.

[Potassium hydroquinone sulfonate]

[Sodium 5,5'-sulfonylbis (2-fluorobenzenesulfonate)]

In one embodiment of the present invention, the third unit is a unit selected from the group consisting of the following formulas (C) to (E).

≪ RTI ID = 0.0 &

[Chemical Formula D]

(E)

In one embodiment of the present disclosure, the third unit is selected from the group consisting of 2,6-difluorobenzonitrile, 4,4-difluorobenzophenone and hydroquinone (hydroquinone). < / RTI >

In one embodiment of the present invention, when the third monomer unit is used, polymerization can be performed at a molecular weight higher than that of the multi-block polymerized unit using only two different first monomer units and second monomer units, As shown in FIG. Further, by combining the hydrophilic blocks in the above-described manner, the conductivity is improved in the low humidification region.

In one embodiment of the present invention, the sum of the weights of the first unit body and the second unit body and the weight ratio of the third unit body is 3: 1 to 20: 1.

In one embodiment of the present invention, the hydrophilic block may be represented by the following formula (4).

[Chemical Formula 4]

In Formula 4, R1 to R5, a to f, a 'to c' and M are as defined in Formula (1), and 1, m and n are each independently an integer of 1 to 300.

In one embodiment of the present invention, the hydrophilic block comprises three different first units, second units and third units, and the unit having no ion-exchanger or the ion-exchanger-containing unit . Here, the functional group of the ion exchange group is ^{_{-SO 3 H, -SO 3 - M}} +, -COOH, -COO - M +, -PO 3 H 2, -PO 3 H - M +, -PO 3 2- 2M + , _{-O (CF 2) m SO 3} H, -O (CF 2) m SO 3 - M +, -O (CF 2) m COOH, -O (CF 2) m COO - M +, -O (CF 2 ) _m PO ₃ H ₂ , -O (CF ₂ ) _m PO ₃ H ^- M ⁺ , and -O (CF ₂ ) _m PO ₃ ^{2 -} 2M ⁺ . Here, M may be a metallic element. That is, the functional group may be hydrophilic.

The hydrophobic block means the polymer block having substantially no ion exchanger. Here, the " block having substantially no ion-exchanger " means a block represented by the number of ion-exchange groups per one structural unit constituting the block, and the average block is less than 0.1, more preferably 0.05 or less, Is more preferable.

In one embodiment of the present disclosure, the hydrophobic block comprises at least one hydrophobic block comprising at least one of the group consisting of 4,4-difluorobenzophenone, 9,9-bis (hydroxyphenyl) fluorine and monomers derived from potassium carbonate .

In one embodiment of the present invention, the hydrophobic block may be represented by the following general formula (5).

[Chemical Formula 5]

In Formula 5, o and p are each independently an integer of 1 to 300.

The term " multi-block " in the present application means that in addition to the copolymerization mode in which the hydrophilic block and the hydrophobic block form a main chain structure, one block forms a main chain structure and the other block forms a branched structure Is a concept including a copolymer of a graft polymerization type.

In the present application, O represents oxygen, N represents nitrogen, S represents sulfur, Si represents silicon, and H represents hydrogen.

In one embodiment of the present disclosure, the polymer may further include a brancher. In the present specification, a brancher serves to connect or crosslink the polymer chain.

In the present specification, in the case of a polymer further comprising the above-mentioned brancher, the brancher can directly constitute the main chain of the polymer, and the mechanical integration degree of the thin film can be improved. For example, the branched polymer of the present invention can be produced by polymerizing a branched hydrophilic block containing an acid substituent and a branched hydrophobic block containing no acid substituents, Without branching or cross-linking of sulfonated polymers, branchers can directly constitute the main chain of the polymer and maintain the mechanical integrity of the thin film. Hydrophilic blocks that impart ionic conductivity to the minority block and the thin film can be alternately led to chemical bonding.

Also, in one embodiment of the present disclosure, the brancher may be represented by any one of the following structures, but is not limited thereto.

,

,

,

,

,

,

,

,

,

,

,

,

,

,

In one embodiment of the present invention, the weight average molecular weight of the hydrophilic block is from 5,000 g / mol to 100,000 g / mol.

In one embodiment of the present invention, the weight average molecular weight of the hydrophobic block is from 5,000 g / mol to 70,000 g / mol.

In one embodiment of the present invention, the weight average molecular weight of the multi-block polymer is 100,000 g / mol to 2,000,000 g / mol, and more preferably 150,000 g / mol to 1,000,000 g / mol. The use of only two different first monomer units and second monomer units and the failure to use the third monomer units does not satisfy the range of the molecular weight, thereby deteriorating the physical properties of the electrolyte membrane. Accordingly, when the molecular weight of the multi-block polymer is in the above range, the mechanical properties of the electrolytic membrane including the multi-block polymer are not lowered, the solubility of the polymer is maintained, The conductivity can be improved.

An electrolyte membrane according to one embodiment of the present disclosure may be manufactured using materials and / or methods known in the art, except that the electrolyte membrane includes a multi-block polymer including the hydrophilic block and the hydrophobic block.

The electrolyte membrane according to one embodiment of the present invention is obtained by condensation polymerization of a hydrophilic block and a hydrophobic block-bound multi-block polymer, dissolving the multi-block polymer in a solvent to prepare a polymer solution composition, The polymer film can be cast and dried by a casting method to produce an electrolyte membrane.

In one embodiment of the present invention, the ionic conductivity of the electrolyte membrane is from 0.001 S / cm to 0.3 S / cm to be.

In one embodiment of the present invention, the ionic conductivity of the polymer electrolyte membrane can be measured under a humidifying condition. In the present specification, the humidification line refers to the relative humidity (RH) Can be from 30% to 100%.

Measurement of ion conductivity

The ionic conductivity of the electrolyte membrane was measured using the 4-probe method. The frequency range was measured by a complex impedance method between 10 Hz and 1 MHz and Nyquist plots were plotted to obtain the bulk resistance value. The ionic conductivity of the electrolyte membrane was calculated by the following equation (1). Where L is the distance between the two sensor electrodes is fixed at 0.425. R is the bulk resistance of the electrolyte membrane, w is the width of the electrolyte membrane, and t is the thickness of the electrolyte membrane.

[Formula (1)

? = {L / (R * w * t)} * 100

In one embodiment of the present invention, the ion exchange capacity (IEC) value of the electrolyte membrane is 0.01 mmol / g to 5.0 mmol / g. When the ion exchange capacity value is within the range, ion channels are formed in the polyelectrolyte membrane, and the block copolymer may exhibit ion conductivity.

In one embodiment of the present invention, the thickness of the electrolyte membrane is 1 to 500 mu m. The polymer electrolyte membrane having the above-described range of thickness can reduce electric short and cross-over of the electrolyte material and exhibit excellent cation conductivity. Particularly, in the low humidification region, the ionic conductivity shows an effect of improving the ionic conductivity.

The disclosure also includes an anode; Cathode; And the above-described polymer electrolyte membrane provided between the anode and the cathode.

The membrane-electrode assembly (MEA) means a junction body of an electrode (cathode and anode) where an electrochemical catalytic reaction of fuel and air takes place and a polymer membrane in which hydrogen ions are transferred, and the electrode (cathode and anode) It is a single integral unit.

The membrane-electrode assembly of the present invention can be produced by a conventional method known in the art, such that the catalyst layer of the anode and the catalyst layer of the cathode are in contact with the electrolyte membrane. For example, the cathode; Anode; And an electrolyte membrane positioned between the cathode and the anode in close contact with each other at 100 to 400 ° C.

The anode electrode may include an anode catalyst layer and an anode gas diffusion layer. The anode gas diffusion layer may again include an anode microporous layer and an anode electrode substrate.

The cathode electrode may include a cathode catalyst layer and a cathode gas diffusion layer. The cathode gas diffusion layer may again include a cathode microporous layer and a cathode electrode substrate.

FIG. 2 schematically illustrates the principle of electricity generation of a fuel cell. In a fuel cell, a basic unit for generating electricity is a membrane electrode assembly (MEA), which includes an electrolyte membrane 100 and an electrolyte membrane 100, And an anode 200a and a cathode 200b electrodes formed on both sides of the cathode 200a. 1 showing the principle of electricity generation of a fuel cell, in the anode 200a, oxidation reaction of a fuel such as hydrogen or hydrocarbons such as methanol or butane occurs to generate hydrogen ions (H ⁺ ) and electrons (e ^- ) , The hydrogen ions move to the cathode 200b through the electrolyte membrane 100. [ In the cathode 200b, hydrogen ions transferred through the electrolyte membrane 100 react with an oxidizing agent such as oxygen and electrons to generate water. This reaction causes electrons to migrate to the external circuit.

The catalyst layer of the anode electrode is preferably a catalyst selected from the group consisting of platinum, ruthenium, osmium, platinum-ruthenium alloy, platinum-osmium alloy, platinum-palladium alloy and platinum- Lt; / RTI > The catalyst layer of the cathode electrode is a place where a reduction reaction of an oxidizing agent occurs, and a platinum or platinum-transition metal alloy can be preferably used as a catalyst. The catalysts can be used not only by themselves but also by being supported on a carbon-based carrier.

The process of introducing the catalyst layer can be performed by a conventional method known in the art. For example, the catalyst ink may be directly coated on the electrolyte membrane or coated on the gas diffusion layer to form the catalyst layer. The method of coating the catalyst ink is not particularly limited, but spray coating, tape casting, screen printing, blade coating, die coating or spin coating may be used. The catalyst ink may typically consist of a catalyst, a polymer ionomer and a solvent.

The gas diffusion layer serves as a current conductor and serves as a passage for reacting gas and water, and has a porous structure. Therefore, the gas diffusion layer may include a conductive base material. As the conductive substrate, carbon paper, carbon cloth or carbon felt can be preferably used. The gas diffusion layer may further include a microporous layer between the catalyst layer and the conductive base. The microporous layer can be used to improve the performance of the fuel cell under low humidification conditions and serves to reduce the amount of water flowing out of the gas diffusion layer to make the electrolyte membrane sufficiently wet.

One embodiment of the present disclosure includes at least two membrane-electrode assemblies; A stack including a bipolar plate disposed between the membrane-electrode assemblies; A fuel supply unit for supplying fuel to the stack; And an oxidant supply unit for supplying an oxidant to the stack.

Fuel cells are energy conversion devices that convert the chemical energy of a fuel directly into electrical energy. That is, a fuel cell uses a fuel gas and an oxidizing agent, and generates electricity using electrons generated during the oxidation-reduction reaction.

The fuel cell can be manufactured according to a conventional method known in the art using the above-described membrane-electrode assembly (MEA). For example, the membrane electrode assembly (MEA) and the bipolar plate may be fabricated.

The fuel cell of the present invention comprises a stack, a fuel supply, and an oxidant supply.

3 schematically shows the structure of a fuel cell, which includes a stack 60, an oxidant supply unit 70, and a fuel supply unit 80. [

The stack 60 includes one or more of the membrane electrode assemblies described above and includes a separator interposed therebetween when two or more membrane electrode assemblies are included. The separator serves to prevent the membrane electrode assemblies from being electrically connected and to transfer the fuel and oxidant supplied from the outside to the membrane electrode assembly.

The oxidant supply part 70 serves to supply the oxidant to the stack 60. As the oxidizing agent, oxygen is typically used, and oxygen or air can be injected into the pump 70 and used.

The fuel supply unit 80 serves to supply the fuel to the stack 60 and includes a fuel tank 81 for storing the fuel and a pump 82 for supplying the fuel stored in the fuel tank 81 to the stack 60 Lt; / RTI > As the fuel, gas or liquid hydrogen or hydrocarbon fuel may be used. Examples of hydrocarbon fuels include methanol, ethanol, propanol, butanol or natural gas.

The fuel cell may be a polymer electrolyte fuel cell, a direct liquid fuel cell, a direct methanol fuel cell, a direct formic acid fuel cell, a direct ethanol fuel cell, or a direct dimethyl ether fuel cell.

When the electrolyte membrane according to one embodiment of the present invention is used as an ion exchange membrane of a fuel cell, the above-described effect can be obtained.

Hereinafter, examples and comparative examples are provided to facilitate understanding of the contents of the present specification. However, the content of the present specification is not limited to the following examples.

≪ Example 1 >

1) Synthesis of polymer

A three-necked flask was used as a reactor by connecting a dean-stark filled with a molecular sieve and a condenser, and another type of sodium 5,5'-sulfonylbis (2- Sulfonylbis (2-fluorobenzene sulfonate), hydroquinone sulfonic acid potassium salt and 2,6-difluorobenzonitrile (2,6-difluorobenzonitrile) (NMP) or dimethylsulfoxide (DMSO) as a catalyst, depending on the solubility of the monomer, in a reaction solvent and a benzene solvent in the presence of potassium carbonate as a catalyst. The mixture was stirred at a temperature of 140 ° C. for 4 hours and then subjected to a benzene evaporation process by an azeotropic distillation method and then condensation polymerization was carried out at 180 to 190 ° C. for 20 hours. Back to 60 ℃ After the reaction was stopped, 4,4-difluorobenzophenone, 9,9-bis (hydroxyphenyl) fluorine and potassium carbonate were added, and the reaction was resumed in a reaction solvent and a benzene solvent. After the reaction was completed, the temperature was lowered to room temperature, and then the product was poured into an excess amount of methanol, and the product was distilled from the solvent After washing, the filtrate was filtered through a filter and dried in a vacuum oven at 80 ° C to remove the hydrophilic block and the hydrophobic block And finally a combined multi-block copolymer was obtained.

2) Preparation of polymer electrolyte membrane

The polymer resin obtained in 1) was dissolved in a dimethylsulfoxide (DMSO) solvent in a desired ratio, and water was added thereto at a specific ratio after the filtration, followed by stirring to prepare a solution. The polymer solution was used to cast a polymer film by a bar casting method, which was performed by using a doctor blade on a substrate of an applicator. The cast film was held in an applicator at 50 DEG C for at least 2 hours and then dried in an oven at 100 DEG C for a day. The dried electrolyte membrane was immersed in a ₁ M sulfuric acid aqueous solution at 80 ° C to replace the sulfonic acid group with the -SO ₃ H form, thereby completing the electrolyte membrane.

≪ Example 2 >

A multi-block polymer was prepared in the same manner as in Example 1, except that 4,4-difluorobenzophenone was used instead of 2,6-difluorobenzonitrile in the polymer synthesis step of Example 1, To prepare an electrolyte membrane.

≪ Example 3 >

A multi-block polymer was prepared in the same manner as in Example 1 except that 2,6-difluorobenzonitrile was replaced with hydroquinone in the polymer synthesis step of Example 1, and an electrolyte membrane was prepared in the same manner.

≪ Comparative Example 1 &

A multi-block polymer was prepared in the same manner as in Example 1 except for using 2,6-difluorobenzonitrile in the polymer synthesis step of Example 1 of Example 1, and an electrolyte membrane was prepared in the same manner.

≪ Comparative Example 2 &

In the same manner as in Example 1 except that sodium 5,5'-sulfonylbis (2-fluorobenzenesulfonate) (sodium 5,5'-sulfonylbis (2-fluorobenzenesulfonate) , And an electrolyte membrane was prepared by the same method.

≪ Comparative Example 3 &

In the polymer synthesis step of Example 1, a multi-block polymer was prepared in the same manner as in Example 1 except hydroquinone sulfonic acid, and an electrolyte membrane was prepared in the same manner.

Molecular weight measurement

After completion of the synthesis, an appropriate amount of the sample was sampled and the molecular weight of the multi-block polymer was measured using a GPC (Gel Permeation Chromatography) analyzer. The analysis conditions are as follows.

Column: PL mixed B, C

Solvent: DMF / LiBr (0.45 m filtered)

Flow rate: 1.0 ml / min

Concentration: 1 mg / mL (100 μL injection)

Column temperature: 65 ºC

Detector: Waters RI detector

Standard: PS 7,200 ~ 3,900,000 Da.

Data processing: Empower2

The molecular weight analysis results of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1 below.

Multiblock polymer molecular weight (Mw) Example 1 150K ~ 250Kg / mol Example 2 200K ~ 300Kg / mol Example 3 200K ~ 300Kg / mol Comparative Example 1 40K ~ 100Kg / mol Comparative Example 2 350K ~ 800Kg / mol

Water absorption measurement

The method of measuring the water absorption of the prepared polymer electrolyte membrane is as follows. First, the electrolyte membrane was completely dried for more than one day in a 80 ° C vacuum oven, and the mass and diagonal length of the membrane were measured. Then, the dried membranes were immersed in distilled water at room temperature for one day to swell completely, and then the surface of the membrane was quickly wiped off and the mass and diagonal length of the membrane were measured. After measuring the mass and diagonal length of the membrane in this way, the calculation can be carried out as follows.

Water Absorption

= {(Mass of hygroscopic membrane - mass of dried membrane) / mass of dried membrane} * 100

The water absorption of Example 3 and Comparative Example 3 was measured and is shown in Table 2 below.

Water uptake Example 3 70 to 80% Comparative Example 3 110 to 130%

As shown in the results of Table 1, the molecular weight of the final multi-block polymer was low in Comparative Example 1 in which the polymer was polymerized in the form of a sulfonic acid group in all the benzene rings of the hydrophilic block of the multi-block polymer . When the electrolyte membrane is manufactured using this, a small-sized film can be obtained, but it is difficult to obtain a large-sized electrolyte membrane having good mechanical properties. On the other hand, in the case of Examples 1 to 3, when an additional monomer having no sulfonic group was added to monomers having two types of sulfonic acid groups, polymer having a certain molecular weight (150,000 g / mol or more) .

FIG. 1 shows the ion conductivity according to the humidifying state of the electrolyte membrane thus produced. The molecular weight of the polymer was higher when the hydrophilic block was composed of a monomer having a sulfonic acid group and a monomer having no sulfonic acid group in Comparative Example 2 and the ionic conductivity Values are lower than those of Examples 1 to 3.

It can be seen from Examples 1 to 3 that the results of Example 3 are the best in the RH 30, 50, and 80% humidification regions. RH 30% shows a similar conductivity value to that of Example 3 in Example 1. [ It can be seen from the results that Examples 1 and 3, in which the number of benzene rings is relatively small when a monomer having no sulfonic acid group is added in a hydrophilic block structure, exhibit improved low humidification ion conductivity as compared with Example 2.

The results of the above Table 2 show that the polymer of Comparative Example 3 exhibits high absorption when synthesized within a similar ion exchange capacity (IEC) range. From the viewpoint of dimensional stability, dimensional stability is unstable, which deteriorates the physical properties of the electrolyte membrane, which is problematic for use as an electrolyte membrane for MEA. However, in the case of Example 3, the water uptake is low within a similar IEC range, which is more effective in terms of dimensional stability than Comparative Example 3. [ (Comparative Example 3 is compared with Example 3 only because the monomers used in Example 3 are capable of reacting with sodium 5,5'-sulfonylbis (2-fluorobenzenesulfonate) monomer with the terminal group being -OH However, in Examples 1 and 2, since the terminal group is -F, it is impossible to react with the sodium 5,5'-sulfonylbis (2-fluorobenzenesulfonate) monomer.

100: electrolyte membrane
200a: anode
200b: cathode
60: Stack
70: oxidant supplier
80: fuel supply unit
81: Fuel tank
82: Pump

Claims (15)

A first unit represented by the following formula (1); A second unit represented by the following formula (2); And a third unit represented by the following formula (3) and a hydrophobic block:
[Chemical Formula 1]

(2)

(3)

In the general formulas (1) to (3), R1 to R5 are the same or different from each other and each independently represents hydrogen; heavy hydrogen; A halogen group; Cyano; A substituted or unsubstituted alkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group,
M is a Group 1 element,
a to c are each an integer of 0 to 3, a 'to c' are each an integer of 1 to 4, d and e are each an integer of 1 to 4, f is 0 or 1,
a to e and a 'to c' are two or more, the substituents in the parentheses are the same or different from each other, a + a'≤4, b + b'4, and c + c'4. The multi-block polymer of claim 1, wherein M is sodium or potassium. The multi-block polymer of claim 1, wherein R4 is hydrogen or a cyano group. [2] The method according to claim 1, wherein the compound represented by Formula 1 is represented by Formula A,
Wherein the formula (2) is a multi-block polymer represented by the following formula (B):
(A)

[Chemical Formula B]

[3] The method according to claim 1, wherein the third unit is selected from the group consisting of 2,6-difluorobenzonitrile, 4,4-difluorobenzophenone, and hydroquinone. Wherein the polymer is a unit derived from at least one compound selected from the group consisting of The multi-block polymer according to claim 1, wherein the sum of the weights of the first unit and the second unit and the weight ratio of the third unit are 3: 1 to 20: 1. The multi-block polymer of claim 1, wherein the hydrophilic block has a weight average molecular weight of from 5,000 g / mol to 100,000 g / mol. The multi-block polymer of claim 1, wherein the hydrophobic block has a weight average molecular weight of from 5,000 g / mol to 70,000 g / mol. [3] The method of claim 1, wherein the weight average molecular weight of the multi-block polymer is 120,000 g / mol to 2,000,000 g / mol A multi-block polymer. A polymer electrolyte membrane comprising a multi-block polymer according to any one of claims 1 to 9. The electrolyte membrane according to claim 10, wherein the electrolyte membrane has an ion conductivity of 0.001 S / cm to 0.3 S / cm. The electrolyte membrane according to claim 10, wherein the ion exchange capacity (IEC) value of the electrolyte membrane is 0.01 mmol / g to 5.0 mmol / g. The electrolyte membrane according to claim 10, wherein the electrolyte membrane has a thickness of 1 탆 to 500 탆 ≪ / RTI > Anode; Cathode; And an electrolyte membrane according to claim 10 provided between the anode and the cathode. A stack comprising at least two membrane-electrode assemblies according to claim 14 and a bipolar plate provided between the membrane-electrode assemblies;
A fuel supply unit for supplying fuel to the stack; And
And an oxidant supplier for supplying an oxidant to the stack.

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