KR20180050142A - Polymer, electrolyte membrane comprising the same, fuel cell and redox flow battery including the same - Google Patents

Abstract

The present invention relates to a polymer, an electrolyte membrane containing the same, a fuel cell including the same, and a redox flow battery. To this end, the polymer includes a repeating unit represented by chemical formula 1, and ensures excellent durability and acid resistance.

Description

TECHNICAL FIELD [0001] The present invention relates to a polymer electrolyte membrane, a polymer electrolyte membrane, and a fuel cell and a redox flow battery including the polymer electrolyte membrane.

Polymer, a membrane of an electrolyte containing the same, a fuel cell and a redox flow battery containing the same.

A polymer is a compound having a large molecular weight and refers to a compound formed by polymerizing a plurality of small molecules called a monomer. Polymers can be classified into linear polymers, branched polymers, and crosslinked polymers depending on the structure and form of the chains, and there are significant differences in physical and chemical properties depending on the structure.

Polymers have superior mechanical strength compared to relatively light weight and have good workability. They have been mainly used as materials for structuring, but recently their use as functional materials has been emphasized due to their excellent physical and chemical properties.

Typical examples are polymer membranes. The polymer separator means not only a thin film such as a film but a polymer membrane having a function of separating the material. Specifically, it is used as an electrolyte membrane capable of cation exchange such as a fuel cell and a redox flow cell.

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.

Redox Flow Battery (Redox Flow Battery) is a system in which an active substance contained in an electrolyte is oxidized and reduced to be charged and discharged. An electrochemical storage device that stores chemical energy of an active substance directly as electric energy to be. The unit cell of the redox flow battery includes an electrode, an electrolyte, and an ion exchange membrane (electrolyte membrane).

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

One of the key components of the fuel cell and the redox flow cell is a polymer electrolyte membrane capable of cation exchange, 1) excellent proton conductivity 2) prevention of cross over of electrolyte 3) strong chemical resistance 4) mechanical properties Reinforcing and / or 4) 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 because it has a fluorine-based 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.

Research has been conducted on monomers used in the synthesis of polymers to produce polymer membranes for fuel cells and / or redox flow cells with high durability and acid resistance. Further, in order to increase the utilization of the partially fluorinated polymer electrolyte membrane, studies have been made on a partial fluorinated polymer electrolyte membrane having improved proton conductivity, mechanical properties, and physical and chemical properties.

Korean Laid-Open Publication No. 2003-0076057

The present invention seeks to provide a polymer and an electrolyte membrane containing the same.

One embodiment of the present invention provides a polymer comprising a repeating unit represented by the following formula (1).

[Chemical Formula 1]

In Formula 1, X1 and X2 are the same or different and each independently O or S,

R1 and R2 are the same or different from each other, and each independently hydrogen; heavy hydrogen; A halogen group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group.

M is hydrogen or an alkali metal ion,

m is an integer of 0 to 3, n is an integer of 0 to 4,

q and s are each 0 or 1, q + s? 1,

r and t are each an integer of 1 to 6,

p is an integer of 1 to 3,

When m, n, p, r and t are 2 or more, the substituents in the parentheses are the same or different.

The present specification also provides a polymer electrolyte membrane comprising the above-mentioned polymer.

The present disclosure relates to an anode; Cathode; And the above-described polymer electrolyte membrane provided between the anode and the cathode.

The present specification discloses a stack comprising two or more of the above-described membrane-electrode assemblies, and 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.

Finally, the present specification discloses a positive electrode comprising a positive electrode and a positive electrode electrolyte; A negative electrode cell comprising a negative electrode and a negative electrode electrolyte; And a polymer electrolyte membrane provided between the anode cell and the cathode cell.

The polymer in one embodiment of the present specification is excellent in durability and acid resistance.

The polymer according to one embodiment of the present invention enhances the proton conductivity by reducing the pKa value by introducing the partial fluorinated sulfonic acid into the hydrocarbon main chain, and in particular, C is the reaction position of the main chain site and the site of the sulfonic acid group which gives an ion-transferring effect, and the phase separation performance of the electrolyte membrane is improved due to the effect of π-π stacking of a plurality of phenyl linkages.

In addition, the polymer according to one embodiment of the present disclosure comprises a thioether (-S-) repeating unit. In this case, since it forms a wider ion channel at low humidification compared to polymers containing (-O-) repeating units, it has a lower proton conductivity than a lower humidification.

The polymer electrolyte membrane comprising a polymer according to one embodiment of the present disclosure easily forms a hydrophilic-hydrophobic phase-separation structure.

In addition, the polymer electrolyte membrane effectively controls the hydrophilic channel in the polyelectrolyte membrane by controlling the phase separation structure.

In addition, the polymer electrolyte membrane is excellent in proton conductivity. As a result, the performance of the fuel cell and / or the redox flow battery including the same is improved.

1 is a schematic view showing an electricity generation principle of a fuel cell.
2 is a schematic view showing an embodiment of a redox flow battery.
3 is a schematic view showing one embodiment of a fuel cell.

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

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; Or an alkoxy group, or does not have any substituent (s).

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, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, isobutyl, sec-butyl, It is 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 is not particularly limited, but preferably has 6 to 30 carbon atoms, and the aryl group may be monocyclic or polycyclic.

When the aryl group is a monocyclic 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, but are not limited to, a naphthyl group, an anthracenyl group, a phenanthryl group, a triphenyl group, a pyrenyl group, a perylenyl group, a klycenyl group and a fluorenyl group.

In the present specification, the fluorenyl group may be substituted, and adjacent groups may combine with each other to form a ring.

,

및

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 heteroaryl group includes at least one non-carbon atom and at least one hetero atom. Specifically, the hetero atom may include one or more atoms selected from the group consisting of O, N, Se and S, and the like. The number of carbon atoms is not particularly limited, but is preferably 2 to 30 carbon atoms, and the heteroaryl group may be monocyclic or polycyclic. Examples of the heterocyclic group include a thiophene group, a furanyl group, a pyrrolyl group, an imidazolyl group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, A substituted or unsubstituted heterocyclic group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted heterocyclic group, , An isoquinolinyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a benzimidazolyl group, a benzothiazolyl group, a benzocarbazolyl group, a benzothiophene group, a dibenzothiophene group, a benzofuranyl group, But are not limited to, phenanthroline, thiazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, benzothiazolyl, phenothiazyl and dibenzofuranyl groups.

As used herein, the term " repeating unit " means a structure in which a compound is contained in the polymer in a form of two or more groups by polymerization reaction.

Whenever a component is referred to as "comprising ", it is understood that it may include other components as well, without departing from the other components unless specifically stated otherwise.

In one embodiment of the present invention, the alkali metal is an element belonging to Group 1 of the periodic table.

In one embodiment of the present disclosure, the alkali metal is selected from the group consisting of Li, Na and K.

In one embodiment of the present disclosure, the alkali metal is K.

In one embodiment of the present invention, the repeating unit of formula (1) is represented by the following formula (2).

(2)

In the above formula (2), the definitions of R1, R2, m, n, p, r, t and M are as defined in the formula (1).

In one embodiment of the present invention, the repeating unit represented by the formula (1) is represented by the following formula (1-1) or (1-2).

[Formula 1-1]

[Formula 1-2]

In the above formulas 1-1 and 1-2,

X1, X2, p, q, r, s, t and M are as defined in the formula (1).

In one embodiment of the present invention, the repeating unit represented by the formula (1) may be represented by any of the following formulas (3) to (8).

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

In one embodiment of the present invention, the polymer includes only the repeating unit represented by the above formula (1).

In one embodiment of the present invention, the polymer may be prepared by a method known in the art, and specifically, the polymer may be prepared by a nucleophilic substitution reaction method.

In another embodiment, the polymer may further comprise a repeating unit other than the repeating unit represented by the formula (1).

In one embodiment of the present invention, the polymer further comprises a repeating unit represented by the following general formula (9).

[Chemical Formula 9]

For Formula 9, and X3 is SO ₂ or CO,

u is an integer of 0 to 5;

In one embodiment of the present specification, the polymer further comprises repeating units of any one of the following formulas (10) to (13).

[Chemical formula 10]

(11)

[Chemical Formula 12]

[Chemical Formula 13]

In one embodiment of the present invention, the repeating unit represented by the above-mentioned formula (1) comprises 30 mol% to 100 mol%, preferably 50 mol% to 100 mol%, based on 100 mol% Mol%.

In one embodiment of the present invention, when the polymer further comprises the repeating unit of Formula 3, the content of the repeating unit represented by Formula 1 is preferably 30 mol% to 70 mol%.

According to one embodiment of the present invention, the repeating unit of formula (1) serves to regulate the ionic conductivity of the separator.

In one embodiment of the present disclosure, the weight average molecular weight of the polymer is from 500 g / mol to 2,000,000 g / mol. When the weight average molecular weight of the polymer is in the above range, the mechanical properties of the electrolyte membrane containing the polymer are not lowered, the solubility of the appropriate polymer is maintained, and the electrolyte membrane can be easily produced.

In one embodiment of the present disclosure, the polymer is a random polymer or a block polymer.

In one embodiment of the present invention, the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) may constitute a random polymer.

In one embodiment of the present disclosure, the polymer may be a block polymer. More specifically, the block polymer comprises a hydrophilic block and a hydrophobic block, and the hydrophilic block may comprise a repeating unit of the formula (1).

In one embodiment of the present disclosure, in the block polymer, the hydrophilic block and the hydrophobic block are included in a molar ratio of 1: 0.1 to 1:10. In one embodiment of the present disclosure, in the block polymer, the hydrophilic block and the hydrophobic block are contained in a molar ratio of 1: 0.1 to 1: 2.

In one embodiment of the present invention, the monomer derived from the compound represented by the formula (1) in the hydrophilic block is contained in an amount of 30 mol% to 70 mol% based on the hydrophilic block.

In one embodiment of the present disclosure, the number average molecular weight of the hydrophilic block is from 1,000 g / mol to 500,000 g / mol. In a specific embodiment, from 2,000 g / mol to 300,000 g / mol. And in another embodiment from 2,500 g / mol to 100,000 g / mol.

In one embodiment of the present disclosure, the number average molecular weight of the hydrophobic block is from 1,000 g / mol to 500,000 g / mol. In a specific embodiment, from 2,000 g / mol to 300,000 g / mol. And in another embodiment from 2,500 g / mol to 100,000 g / mol.

According to the embodiment of the present invention, in the case of a block polymer, separation of the hydrophilic block and the hydrophobic block is clearly distinguished, so that phase separation is easy and ion transfer can be facilitated. According to one embodiment of the present invention, when the repeating unit represented by Formula 1 is included, the separation between the hydrophilic block and the hydrophobic block becomes more clear, and the ion transporting effect can be superior to that of the conventional polymer.

In one embodiment of the present invention, the block polymer includes a hydrophilic block including the repeating unit represented by the formula (1) and a hydrophobic block including the repeating unit represented by the formula (9).

 In one embodiment of the present disclosure, the block polymer is represented by the following formula (A).

(A)

In the above formula (A)

The definitions of X1 to X3, R1, R2, M, m, n, p, q, r, s, t and u are as defined in the formulas (1)

x and y are each an integer of 1 to 100,000, and when x and y are each 2 or more, the repeating units in the parentheses are the same or different from each other.

In one embodiment of the present disclosure, the terminal group of the polymer is hydrogen; Or a halogen group.

In one embodiment of the present disclosure, the terminal group of the polymer is hydrogen; Or a fluorine group.

The block polymer means a polymer composed of one block and one or more blocks different from the block connected to each other through a main chain of the polymer.

As used herein, the term "hydrophilic block" means a block having an ion-exchange group as a functional group. Wherein the functional groups are ^{_{-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 above-mentioned "block having an ion-exchange group" means an average of 0.5 or more ion exchange groups per one structural monomer constituting the block, and an average of 1.0 or more ions per structural monomer It is more desirable to have an exchange.

As used herein, the term "hydrophobic block" means the polymer block having substantially no ion exchanger.

The above-mentioned "block having substantially no ion exchanger" means a block represented by the number of ion-exchange groups per one structural monomer constituting the block and less than 0.1 on the average, more preferably 0.05 or less, It is more preferable that the block has no ion exchanger.

In one embodiment of the present disclosure, the polymer further comprises a brancher.

In the present specification, a brancher serves to connect or crosslink the polymer chain.

In the present specification, in the case of the polymer further comprising the above-mentioned branching agent, the branching 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 polymers of the present invention can be prepared by polymerizing a branched hydrophilic block comprising a branched hydrophobic block that does not contain acid substituents and an acid substituent, Without branching or post-sulfonation or cross-linking of the sulfonated polymer, a brancher directly forms the main chain of the polymer and maintains the mechanical integrity of the film Hydrophilic blocks that impart ionic conductivity to the minority block and the thin film can be alternately led to chemical bonding.

In one embodiment of the present invention, the polymer further comprises a branching agent derived from a compound of the following general formula (20) or a branching agent represented by the following general formula (21).

[Chemical Formula 20]

[Chemical Formula 21]

In formulas (20) and (21)

X is S; O; CO; SO; SO ₂ ; NR; A hydrocarbon-based or fluorine-

R is an aromatic ring substituted with a halogen group; Or an aliphatic ring substituted with a halogen group,

l is an integer from 0 to 100,

When l is 2 or more, two or more X's are the same or different from each other,

Y1 and Y2 are the same or different and are each independently selected from NR _2; An aromatic ring substituted with one or more substituents selected from the group consisting of a hydroxyl group and a halogen group; Or an aliphatic ring substituted by one or more substituents selected from the group consisting of a hydroxyl group and a halogen group,

Z is a trivalent organic group.

In the present specification, the branche derived from the compound of formula (20) is an aromatic ring substituted with a halogen group of each of Y1 and Y2; Or a halogen group of an aliphatic ring substituted with a halogen group may act as a branching agent while being separated from an aromatic ring or an aliphatic ring.

In one embodiment of the present specification, l is 3 or more.

In one embodiment of the present disclosure, X is S.

In another embodiment, X is a haloalkyl group.

In another embodiment of the present disclosure, X is NR.

In one embodiment of the present invention, Y1 and Y2 are the same or different from each other and each independently a halogen-substituted aromatic ring.

In one embodiment of the present specification, Y1 and Y2 are the same or different and are each independently a fluorine-substituted aromatic hydrocarbon ring.

In another embodiment, Y1 and Y2 are each a fluorine-substituted phenyl group. Specific examples thereof include 2,4-phenyl, 2,6-phenyl, 2,3-phenyl, 3,4-phenyl, and the like.

In one embodiment of the present invention, the compound represented by Formula 20 may be represented by any one of the following structures.

In the above structure, X, l, and R are the same as defined in Formula (20).

According to one embodiment of the present invention, Z in the formula (21) may be represented by any one of the following formulas (21-1) to (21-4).

[Formula 21-1]

[Formula 21-2]

[Formula 21-3]

[Formula 21-4]

In Formulas (21-1) to (21-4)

L2 To L < 8 > are the same or different and are each independently a direct bond; -S-; -O-; -CO-; Or -SO ₂ - and,

R10 to R20 are the same or different from each other and each independently hydrogen; heavy hydrogen; A halogen group; Cyano; A nitrile group; A nitro 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 alkenyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group,

a, b, c, f, h, i and j are each an integer of 1 to 4,

d, e and g are each an integer of 1 to 3,

k is an integer of 1 to 6,

In the case where a, b, c, d, e, f, g, h, i, j and k are each an integer of 2 or more, the structures in parentheses two or more are the same or different.

In one embodiment of the present disclosure, L2 is CO.

In yet one embodiment, the L2 is SO _2.

In another embodiment, L2 is S.

In another embodiment, L3 is CO.

In yet one embodiment, the L3 is SO _2.

In another embodiment, L3 is S.

In one embodiment of the present disclosure, L4 is CO.

In yet one embodiment, the L4 is SO _2.

In another embodiment, L4 is S.

In one embodiment of the present disclosure, L5 is CO.

In yet one embodiment, the L5 is SO _2.

In one embodiment of the present specification, L6 is a direct bond.

In another embodiment, L7 is a direct bond.

In one embodiment of the present specification, L8 is a direct bond.

In one embodiment of the present specification, R10 to R20 are hydrogen.

In one embodiment of the present specification, R16 is a halogen group.

In another embodiment, R16 is fluorine.

Further, in one embodiment of the present invention, the branching agent represented by the formula (21) may be represented by any one of the following structures.

The present specification also provides a polymer electrolyte membrane comprising the above-mentioned polymer.

When a polymer containing a monomer derived from the compound according to one embodiment of the present invention is included, it has high mechanical strength and high ion conductivity and can facilitate the phase separation of the electrolyte membrane.

As used herein, the term "electrolyte membrane" is a membrane capable of ion exchange, and includes a membrane, an ion exchange membrane, an ion transport membrane, an ion conductive membrane, a membrane, an ion exchange membrane, A transfer electrolyte membrane, an ion conductive electrolyte membrane, and the like.

The polymer electrolyte membrane according to one embodiment of the present invention can be produced using materials and / or methods known in the art, except that the polymer includes the polymer containing the repeating units.

According to one embodiment of the present invention, the ionic conductivity of the polymer electrolyte membrane is 0.01 S / cm or more and 0.5 S / cm or less. In another embodiment, the ionic conductivity of the polymer electrolyte membrane is 0.01 S / cm or more and 0.3 S / cm or less.

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 humidifying condition may mean a relative humidity (RH) of 10% to 100%.

In one embodiment of the present invention, the ion exchange capacity (IEC) value of the polymer electrolyte membrane is 0.01 mmol / g to 5.0 mmol / g. When the ion exchange capacity value is in the range, the ion channel in the polymer electrolyte membrane is formed, and the polymer can exhibit ion conductivity.

In one embodiment of the present invention, the thickness of the polymer electrolyte membrane is 1 탆 to 500 탆. 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.

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. 1 schematically shows an electricity generating principle 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 hydrogen such as hydrogen or hydrocarbons such as methanol and butane occurs, hydrogen ions (H +) and electrons (e-) are generated, The hydrogen ions move through the electrolyte membrane 100 to the cathode 200b. 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 a stack comprising at least two membrane-electrode assemblies, and 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.

In addition, one embodiment of the present disclosure includes a positive electrode cell including a positive electrode and a positive electrode electrolyte; A negative electrode cell comprising a negative electrode and a negative electrode electrolyte; And a polymer electrolyte membrane according to an embodiment of the present invention provided between the anode cell and the cathode cell.

Redox Flow Battery (Redox Flow Battery) is a system in which an active substance contained in an electrolyte is oxidized and reduced to be charged and discharged. An electrochemical storage device that stores chemical energy of an active substance directly as electric energy to be. The redox flow battery utilizes the principle of charging and discharging electrons by receiving electrons when an electrolyte containing an active material having a different oxidation state meets the ion exchange membrane. Generally, a redox flow battery is composed of a tank containing an electrolyte solution, a battery cell in which charging and discharging occur, and a circulation pump circulating the electrolyte between the tank and the battery cell, and the unit cell of the battery cell includes an electrode, Exchange membrane.

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

The redox flow cell of the present specification can be produced according to a conventional method known in the art, except that it includes a polymer electrolyte membrane according to one embodiment of the present specification.

2, the redox flow battery is divided into a positive electrode cell 32 and a negative electrode cell 33 by an electrolyte film 31. As shown in FIG. The anode cell 32 and the cathode cell 33 each include an anode and a cathode. The anode cell (32) is connected to the anode tank (10) for supplying and discharging the anode electrolyte (41) through a pipe. The cathode cell 33 is also connected to a cathode tank 20 for supplying and discharging the cathode electrolyte 42 through a pipe. The electrolytic solution is circulated through the pumps 11 and 21, and an oxidation / reduction reaction (that is, a redox reaction) in which the oxidation number of ions is changed occurs, thereby charging and discharging occur in the anode and the cathode.

Hereinafter, the present invention will be described in detail by way of examples with reference to the drawings. However, the embodiments according to the present disclosure can be modified in various other forms, and the scope of the present specification is not construed as being limited to the embodiments described below. Embodiments of the present disclosure are provided to more fully describe the present disclosure to those of ordinary skill in the art.

≪ Example 1 >

A 250 mL round flask equipped with a dean-stark apparatus and a condenser was charged with 2.000 g (4.1631 mmol) of perfluorinated 2,4-difluorobenzene, 4,4'-thiobisbenzenethiol 1.0426 g (4.1631 mmol) of N-methyl-2-pyrrolidone (NMP) and 6 mL of toluene were introduced into a nitrogen atmosphere to initiate the reaction using 2.3019 g (16.656 mmol) of potassium carbonate as a catalyst.

The reaction mixture was then stirred for 4 hours in an oil bath at a temperature of 140 ° C to remove the azeotropic mixture by adsorbing molecular sieves on a Dean Stark apparatus while the toluene was flowing back to the reactor, , 4.1531 g (4.1631 mmol) of 4'-difluorodiphenylsulfone and 1.0426 g (4.1631 mmol) of 4,4'-thiobisbenzenethiol were placed, and 8.5 mL of N-methyl-2-pyrrolidone (NMP) (16.656 mmol) of potassium carbonate as a catalyst in a nitrogen atmosphere.

The reaction mixture was then stirred again in an oil bath at a temperature of 140 ° C for 4 hours to adsorb and remove the azeotropic mixture on molecular sieves of the Dean Stark apparatus while the toluene was flowing back, Lt; 0 > C and condensation polymerization was carried out for 5 hours.

Thereafter, the temperature of the reactant was reduced to room temperature, the reaction product was poured into an excess amount of methanol to separate the copolymer from the solvent, and the copolymer obtained by filtration was added again to water to remove the potassium carbonate. And dried for 12 hours or more in a vacuum oven to prepare a multi - block copolymer containing perfluoro sulfonic acid, which is alternately chemically bonded to a hydrophobic block and a hydrophobic block.

1 g of the prepared copolymer was dissolved in 5 mL of N-methyl-2-pyrrolidone (NMP) to prepare a 20 wt / v% solution. The solution was coated on a glass substrate and dried to prepare a film having a thickness of about 50 μm. The ionic conductivity was 0.123 S / cm.

≪ Example 2 >

In the same manner as in Example 1 except that perfluorinated tetrafluorobenzene was used in place of perfluorinated 2,4-difluorobenzene in Example 1 at the same molar ratio, And an electrolyte membrane were prepared. The ionic conductivity of the electrolyte membrane was 0.125 S / cm.

≪ Example 3 >

The procedure of Example 1 was repeated except that perfluorinated 3,5-difluorobenzene was used instead of perfluorinated 2,4-difluorobenzene in the same molar ratio as in Example 1 A multi-block copolymer and an electrolyte membrane were prepared. The ionic conductivity of the electrolyte membrane was 0.125 S / cm.

≪ Comparative Example 1 &

Example 1 was repeated except that disodium 2,2'-disulfonate-4,4'-difluorodiphenylsulfone was used in place of perfluorinated 2,4-difluorobenzene in Example 1, A multi-block copolymer and an electrolyte membrane were prepared. The ionic conductivity of the electrolyte membrane was 0.1 S / cm.

As shown in the performance evaluation of the electrolyte membranes of Examples 1 to 3 and Comparative Example 1, it can be seen that the ionic conductivity of the electrolyte membranes prepared in Examples 1 to 3 is higher than that of the electrolyte membranes prepared in Comparative Examples.

Therefore, the electrolyte membrane including the copolymer according to one embodiment of the present application can exhibit an ionic conductivity superior to that of the conventional electrolyte membrane.

100: electrolyte membrane
200a: anode
200b: cathode
10, 20: tank
11, 21: pump
31: electrolyte membrane
32: anode cell
33: cathode cell
41: anode electrolyte
42: cathode electrolyte
60: Stack
70: oxidant supplier
80: fuel supply unit
81: Fuel tank
82: Pump

Claims (11)

1. A polymer comprising a repeating unit represented by the following formula (1): < EMI ID =
[Chemical Formula 1]

In Formula 1, X1 and X2 are the same or different and each independently O or S,
R1 and R2 are the same or different from each other, and each independently hydrogen; heavy hydrogen; A halogen group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group.
M is hydrogen or an alkali metal ion,
m is an integer of 0 to 3, n is an integer of 0 to 4,
q and s are each 0 or 1, q + s? 1,
r and t are each an integer of 1 to 6,
p is an integer of 1 to 3,
When m, n, p, r and t are 2 or more, the substituents in the parentheses are the same or different. The polymer according to claim 1, wherein the repeating unit of the formula (1) is represented by the following formula (2):
(2)

In the above formula (2), the definitions of R1, R2, m, n, p, r, t and M are as defined in the formula (1). The polymer according to claim 1, wherein the repeating unit represented by the formula (1) is represented by the following formula (1-1) or (1-2):
[Formula 1-1]

[Formula 1-2]

In the above formulas 1-1 and 1-2,
X1, X2, p, q, r, s, t and M are as defined in the formula (1). The polymer according to claim 1, wherein the repeating unit represented by the formula (1) is represented by any one of the following formulas (3) to (8)
(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

[Chemical Formula 8]

The polymer of claim 1, wherein the polymer further comprises a repeating unit represented by the following formula (9):
[Chemical Formula 9]

For Formula 9, and X3 is SO ₂ or CO,
u is an integer of 0 to 5; The polymer of claim 1, wherein the polymer further comprises a repeating unit of any of the following formulas (10) to (13):
[Chemical formula 10]

(11)

[Chemical Formula 12]

[Chemical Formula 13]

The polymer according to claim 1, which comprises from 50 mol% to 100 mol% of the repeating unit represented by the formula (1) based on 100 mol% of the repeating units constituting the polymer. A polymer electrolyte membrane comprising a polymer according to any one of claims 1 to 7. Anode; Cathode; And a polymer electrolyte membrane according to claim 8 provided between the anode and the cathode. At least two membrane-electrode assemblies according to claim 9, and
A stack including a bipolar plate disposed between the membrane-electrode assemblies;
A fuel supply unit for supplying fuel to the stack; And
And an oxidant supplier for supplying the oxidant to the stack. A positive electrode including a positive electrode and a positive electrode electrolyte;
A negative electrode cell comprising a negative electrode and a negative electrode electrolyte; And
The redox flow battery according to claim 8, which is provided between the positive electrode cell and the negative electrode cell.

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