Membrane/electrode assembly for polymer electrolyte fuel cell
View Patent ↗A membrane/electrode assembly for a polymer electrolyte fuel cell, comprising an anode and a cathode each having a catalyst layer containing a proton conductive polymer, and a polymer electrolyte membrane disposed between the anode and the cathode, wherein the proton conductive polymer has an electrical conductivity of at least 0.07 S/cm at a temperature of 80° C. at a relative humidity of 40% and has a water content less than 150 mass %.
1. A membrane/electrode assembly for a polymer electrolyte fuel cell, comprising an anode and a cathode each having a catalyst layer containing a fluoropolymer, and a polymer electrolyte membrane disposed between the anode and the cathode,
wherein the fluoropolymer has an electrical conductivity of at least 0.07 S/cm at a temperature of 80° C. at a relative humidity of 40% and has a water content less than 150 mass %, and
wherein the fluoropolymer has repeating units having a fluorinated structure having a group represented by the following formula (α):
wherein
Q 1 is a perfluoroalkylene group which may have an etheric oxygen atom,
Q 2 is a single bond or a perfluoroalkylene group which may have an etheric oxygen atom,
R f1 is a perfluoroalkyl group which may have an etheric oxygen atom,
X is an oxygen atom, a nitrogen atom or a carbon atom, wherein a is 0 when X is an oxygen atom, a is 1 when X is a nitrogen atom and a is 2 when X is a carbon atom, and
Y is a fluorine atom or a monovalent perfluoroorganic group.
2. The membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 1 , wherein the fluoropolymer has an electrical conductivity of at least 0.08 S/cm at a temperature of 80° C. at a relative humidity of 40%.
3. The membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 1 , wherein the fluoropolymer also has tetrafluoroethylene repeating units.
4. The membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 1 , wherein the perfluoroalylene group in Q 1 is linear.
5. The membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 1 , wherein the perfluoroalylene group in Q 1 is branched.
6. The membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 1 , wherein the perfluoroalylene groups independently have 1 to 6 carbon atoms.
7. The membrane/electrode assembly for a polymer electrolyte fuel cell according to claim 1 , wherein at least one of Q 1 and Q 2 is a C 1-6 perfluoroalkylene goup having an etheric oxygen atom.
8. A polymer electrolyte fuel cell comprising the membrane/electrode assembly of claim 1 .
9. The polymer electrolyte fuel cell according to claim 8 , wherein the fluoropolymer has an electrical conductivity of at least 0.08 S/cm at a temperature of 80° C. at a relative humidity of 40%.
10. A method of generating power, comprising supplying an air to the cathode of the polymer electrolyte fuel cell of claim 8 .
11. The method of claim 10 , wherein the air has a relative humidity of at most 40%.
12. The method of claim 10 , wherein the temperature of the membrane/electrode assembly is maintained at 90° C. or higher.
13. The method of claim 10 , wherein the air has a relative humidity of at most 40% and wherein the temperature of the membrane/electrode assembly is maintained at 90° C. or higher.
14. A method of assembling the membrane/electrode assembly for a polymer electrolyte fuel cell of claim 1 , comprising assembling the anode, cathode and polymer electrolyte membrane disposed between the anode and the cathode.