# US 2010/0167159 A1 · Polyelectrolyte film, film-electrode assembly, and solid-polymer-type fuel cell

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- Number: US 2010/0167159 A1
- Document ID: US20100167159A1
- Status: Published application
- Kind: A1
- Application number: 12/278,794
- Filed: 2007-02-05
- Published: 2010-07-01
- Earliest claimed: 2006-02-24
- Assignees: Kuraray Co., Ltd.
- Inventors: Tomohiro Ono; Shinji Nakai; Hiroyuki Ogi; Takeshi Nakano
- Web page: https://patentgrep.com/patent/US20100167159A1

## CPC

- C08F 297/00: Macromolecular compounds obtained by successively polymerising different monomer systems using a catalyst of the ionic or coordination type without deactivating the intermediate polymer
- C08F 297/02: using a catalyst of the anionic type
- C08J 5/2243: {obtained by introduction of active groups capable of ion-exchange into compounds of the type C08J5/2231}
- C08L 53/00: Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
- C08L 53/005: {Modified block copolymers}
- C08L 53/02: of vinyl-aromatic monomers and conjugated dienes
- C08L 53/025: {modified}
- H01B 1/122: {Ionic conductors}
- H01M 8/1011: Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
- H01M 8/1023: having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
- H01M 8/1067: characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
- C08J 2353/02: of vinyl aromatic monomers and conjugated dienes
- H01M 2300/0082: Organic polymers
- Y02E 60/50: Fuel cells
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A polymer electrolyte membrane comprising as a main ingredient a block copolymer which comprises, as its constituents, a polymer block (A) having as a main unit an aromatic vinyl compound unit and a polymer block (B) forming a flexible phase, and has ion-conducting groups on the polymer block (A), said aromatic vinyl compound unit being such that the hydrogen atom bonded to the α-carbon atom is non-replaced or replaced with an alkyl group or an aryl group optionally having substituent(s), and at least one of hydrogen atoms directly bonded to the aromatic ring is replaced with an alkyl group; and a membrane electrode assembly and a polymer electrolyte fuel cell both of which uses it. The polymer block (A) can have a restraining phase, and/or can be cross-linked. The electrolyte membrane is mild to the environment, has a high ion conductivity and good bonding properties to electrodes, is excellent in moldability, and is not easily influenced by methanol; and displays excellent performance in polymer electrolyte fuel cells, particularly direct methanol fuel cells.

## Claims

### Claim 1

A polymer electrolyte membrane comprising as a main ingredient a block copolymer which comprises, as its constituents, a polymer block (A) having as a main unit an aromatic vinyl compound unit and a polymer block (B) forming a flexible phase, and has ion-conducting groups on the polymer block (A), said aromatic vinyl compound unit being such that the hydrogen atom bonded to the α-carbon atom is non-replaced or replaced with an alkyl group having 1 to 4 carbon atoms or an aryl group which has 6 to 14 carbon atoms and can have 1 to 3 substituents, and at least one of hydrogen atoms directly bonded to the aromatic ring is replaced with an alkyl group having 1 to 8 carbon atoms.

### Claim 2 (depends on 1)

The electrolyte membrane according to claim 1 wherein polymer block (A) is
(1) a polymer block (A1) having as a main unit an aromatic vinyl compound unit represented by the general formula (I)
wherein Ar1 represents an aryl group having 6 to 14 carbon atoms which aryl group is substituted with one alkyl group having 1 to 8 carbon atoms and can further have one or two substituents, and R1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 14 carbon atoms which aryl group can have 1 to 3 substituents, or said polymer block (A) is a polymer block (A2) which is composed of
(2) a polymer block (A2a) having as a main unit an aromatic vinyl compound unit represented by the general formula (II)
wherein Ar2 represents an aryl group having 6 to 14 carbon atoms which aryl group can have 1 to 3 substituents, and R1 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 14 carbon atoms which aryl group can have 1 to 3 substituents,
and a polymer block (A2b) forming a restraining phase which polymer block (A2b) is a polymer block (A2b1) having as a main unit an aromatic vinyl compound unit represented by the general formula (III)
wherein each of R2 to R4 represents, mutually independently, a hydrogen atom or an alkyl group having 1 to 8 carbon atoms but at least one of them is an alkyl group having 1 to 8 carbon atoms, and R5 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
or a crystalline polyolefin block,
and the ion-conducting groups exist on the polymer block (A1) in the case of (1) and on the polymer block (A2a) in the case of (2).

### Claim 3 (depends on 2)

The electrolyte membrane according to claim 2 wherein the aromatic vinyl compound unit represented by the general formula (I) is an aromatic vinyl compound unit represented by the general formula (Ia)
wherein each of R6 to R8 represents, mutually independently, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms but at least one of them is an alkyl group having 1 to 4 carbon atoms, and R9 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group,
and the aromatic vinyl compound unit represented by the general formula (II) is an aromatic vinyl compound unit represented by the general formula (IIa)
wherein each of R16 to R12 represents, mutually independently, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R9 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group.

### Claim 4 (depends on 2)

The electrolyte membrane according to claim 2, wherein the block copolymer comprises the polymer block (A1) and the polymer block (B).

### Claim 5 (depends on 4)

The electrolyte membrane according to claim 4, wherein the mass ratio of the polymer block (A1) to the polymer block (B) is 95:5 to 5:95.

### Claim 6 (depends on 2)

The electrolyte membrane according to claim 2, wherein the block copolymer comprises the polymer block (A2a), the polymer block (A2b) and the polymer block (B).

### Claim 7 (depends on 6)

The electrolyte membrane according to claim 6, wherein the mass ratio of the polymer block (A2b) to the polymer block (B) is 95:5 to 5:95.

### Claim 8 (depends on 6)

The electrolyte membrane according to claim 6, wherein the mass ratio of the sum of the polymer block (A2a) and the polymer block (A2b) to polymer block (B) is 90:10 to 10:90.

### Claim 9 (depends on 2)

The electrolyte membrane according to claim 2, wherein the polymer block (A1) is cross-linked in the case of (1) and the polymer block (A2a) is cross-linked in the case of (2).

### Claim 10 (depends on 9)

The electrolyte membrane according to claim 9, wherein the cross-linking is heat cross-linking, and, in the case of (1), Ar1 in the general formula (I) is an aryl group having 6 to 14 carbon atoms which aryl group is substituted with one alkyl group having 1 to 8 carbon atoms in which alkyl group at least one hydrogen atom is bonded to the carbon atom at the 1-position, and can further have one or two substituents, and, in the case of (2), Ar2 in the general formula (II) is an aryl group having 6 to 14 carbon atoms which aryl group is substituted with one alkyl group having 1 to 8 carbon atoms in which alkyl group at least one hydrogen atom is bonded to the carbon atom at the 1-position, and can further have one or two substituents.

### Claim 11 (depends on 1)

The electrolyte membrane according to claim 1, wherein the polymer block (B) is a polymer block having as a main unit at least one unit selected from the group consisting of an alkene unit having 2 to 8 carbon atoms, a cycloalkene unit having 5 to 8 carbon atoms, a vinylcycloalkene unit having 7 to 10 carbon atoms, a conjugated diene unit having 4 to 8 carbon atoms and a conjugated cycloalkadiene unit having 5 to 8 carbon atoms; and a vinylcycloalkene unit having 7 to 10 carbon atoms, a conjugated diene unit having 4 to 8 carbon atoms and a conjugated cycloalkadiene unit having 5 to 8 carbon atoms in which units, part or all of carbon-carbon double bonds are hydrogenated.

### Claim 12 (depends on 11)

The electrolyte membrane according to claim 11, wherein the polymer block (B) is a polymer block having as a main unit at least one unit selected from the group consisting of an alkene unit having 2 to 8 carbon atoms, a conjugated diene unit having 4 to 8 carbon atoms and a conjugated diene unit having 4 to 8 carbon atoms wherein part or all of carbon-carbon double bonds are hydrogenated.

### Claim 13 (depends on 2)

The electrolyte membrane according to claim 2, wherein the aromatic vinyl compound unit in the general formula (I) or (Ia) or the general formula (III) is a p-methylstyrene unit or a 4-tert-butylstyrene unit, and the polymer block (B) is a polymer block having as a main unit at least one unit selected from the group consisting of a conjugated diene unit having 4 to 8 carbon atoms and a conjugated diene unit having 4 to 8 carbon atoms wherein part or all of carbon-carbon double bonds are hydrogenated.

### Claim 14 (depends on 1)

The electrolyte membrane according to claim 1, wherein the ion-conducting group is a group represented by —SO3M or —PO3HM wherein M represents a hydrogen atom, an ammonium ion or an alkali metal ion.

### Claim 15 (depends on 1)

The electrolyte membrane according to claim 1, wherein the ion exchange capacity is 0.30 meq/g or more.

### Claim 16 (depends on 1)

A membrane electrode assembly comprising the electrolyte membrane according to claim 1.

### Claim 17 (depends on 1)

A polymer electrolyte fuel cell comprising the electrolyte membrane according to claim 1.