# US 8,771,897 B2 · Electrolyte membrane for fuel cell including blend of polymers with different degrees of sulfonation, and membrane-electrode assembly and fuel cell including the same

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- Number: US 8,771,897 B2
- Document ID: US8771897B2
- Status: Granted
- Kind: B2
- Application number: 13/186,652
- Filed: 2011-07-20
- Published: 2012-09-20
- Granted: 2014-07-08
- Earliest claimed: 2011-03-18
- Assignees: Korea Institute of Science and Technology
- Applicants: Hyoung-Juhn Kim; Soo-Kil Kim; Eun Ae Cho; Jong Hyun Jang; Sung Pil Yoon; In Hwan Oh; Jonghee Han; Seong Ahn Hong; Suk-Woo Nam; Tae Hoon Lim
- Inventors: Hyoung-Juhn Kim; Soo-Kil Kim; Eun Ae Cho; Jong Hyun Jang; Sung Pil Yoon; In Hwan Oh; Jonghee Han; Seong Ahn Hong; Suk-Woo Nam; Tae Hoon Lim
- Web page: https://patentgrep.com/patent/US8771897B2

## CPC

- H01M 8/1044: Mixtures of polymers, of which at least one is ionically conductive
- C08J 5/2256: {based on macromolecular compounds obtained by reactions other than those involving carbon-to-carbon bonds, e.g. obtained by polycondensation}
- H01M 8/1027: having carbon, oxygen and other atoms, e.g. sulfonated polyethersulfones [S-PES]
- H01M 8/1032: having sulfur, e.g. sulfonated-polyethersulfones [S-PES]
- C08J 2381/06: Polysulfones; Polyethersulfones
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Disclosed herein is an electrolyte membrane for a fuel cell. The electrolyte membrane includes a blend of polymers with different degrees of sulfonation. The electrolyte membrane can exhibit excellent effects such as improved long-term cell performance and good long-term dimensional stability while at the same time solving the problems of conventional hydrocarbon electrolyte membranes. Further disclosed are a membrane-electrode assembly and a fuel cell including the electrolyte membrane.

## Claims

### Claim 1

An electrolyte membrane for a fuel cell comprising a polymer blend of two poly(aryl ether sulfone)s having different degrees of sulfonation of 35 to 60% and 5 to 35%, the difference in degree of sulfonation between the poly(aryl ether sulfone)s being at least 5 to 40%.

### Claim 2

An electrolyte membrane for a fuel cell comprising a polymer blend of three poly(aryl ether sulfone)s having different degrees of sulfonation of 40 to 60%, 15 to 40% and 5 to 15%, the difference in degree of sulfonation between the poly(aryl ether sulfone)s being at least 5 to 40%.

### Claim 3

An electrolyte membrane for a fuel cell comprising a polymer blend of four poly(aryl ether sulfone)s having different degrees of sulfonation of 45 to 55%, 35 to 45%, 25 to 35% and 15 to 25%, the difference in degree of sulfonation between the poly(aryl ether sulfone)s being at least 5 to 40%.

### Claim 4 (depends on 1)

The electrolyte membrane according to claim 1, wherein the two poly(aryl ether sulfone)s of the polymer blend are block copolymers.

### Claim 5 (depends on 1)

The electrolyte membrane according to claim 1, wherein the two poly(aryl ether sulfone)s of the polymer blend are random copolymers.

### Claim 6 (depends on 2)

The electrolyte membrane according to claim 2, wherein the three poly(aryl ether sulfone)s of the polymer blend are block copolymers.

### Claim 7 (depends on 2)

The electrolyte membrane according to claim 2, wherein the three poly(aryl ether sulfone)s of the polymer blend are random copolymers.

### Claim 8 (depends on 3)

The electrolyte membrane according to claim 3, wherein the three poly(aryl ether sulfone)s of the polymer blend are block copolymers.

### Claim 9 (depends on 3)

The electrolyte membrane according to claim 3, wherein the three poly(aryl ether sulfone)s of the polymer blend are random copolymers.

### Claim 10

An electrolyte membrane for a fuel cell comprising:
a disulfonated poly(ether sulfone) of Formula 1a
and
a monosulfonated poly(ether sulfone) of Formula 1b
wherein
n is a positive integer greater than 1,
a and b are positive fractional ratios such that a+b=1, and
c and d are positive fractional ratios such that c+d=1.

### Claim 11 (depends on 10)

The electrolyte membrane of claim 10 wherein a is about 0.55, and b is about 0.45.

### Claim 12 (depends on 10)

The electrolyte membrane of claim 10 wherein c is about 0.7, and d is about 0.3.

### Claim 13 (depends on 10)

The electrolyte membrane of claim 10 wherein a is about 0.55, b is about 0.45, c is about 0.7, and d is about 0.3.

### Claim 14

An electrolyte membrane for a fuel cell comprising:
a disulfonated poly(ether sulfone) of Formula 2a
and
a monosulfonated poly(ether sulfone) of Formula 2b
wherein
n is a positive integer greater than 1,
Y is O or S,
a and b are positive fractional ratios such that a+b=1, and
c and d are positive fractional ratios such that c+d=1.

### Claim 15 (depends on 14)

The electrolyte membrane of claim 14 wherein a is about 0.55, and b is about 0.45.

### Claim 16 (depends on 14)

The electrolyte membrane of claim 14 wherein c is about 0.5, and d is about 0.5.