Fuel cell electrode catalyst layer, fuel cell electrode, fuel cell membrane electrode assembly and fuel cell having a proton-conductive material coated on a catalyst thereof
A fuel cell electrode catalyst layer ( 13 ) of the preset invention includes: a catalyst ( 131 b ); a support ( 131 a ) that supports the catalyst; and two or more proton-conductive materials ( 133 ) different in dry mass value per mole of a proton-donating group, the proton-conductive materials being in contact with at least a part of the catalyst and at least a part of the support. Then, a proton-conductive material in which a dry mass value per mole of the proton-donating group is highest among the proton-conductive materials is in contact with at least a part of the catalyst, and has a largest contact ratio with a surface of the catalyst.
1. A fuel cell electrode catalyst layer comprising a catalyzer, the catalyzer comprising:
a catalyst;
a support that supports the catalyst; and
two or more proton-conductive materials different in dry mass value per mole of a proton-donating group, all of the proton-conductive materials being in contact with at least a part of the catalyst and at least a part of the support,
wherein a proton-conductive material in which a dry mass value per mole of the proton-donating group is highest among the proton-conductive materials is in contact with at least a part of the catalyst, and has a largest contact ratio of the proton-conductive materials with a surface of the catalyst among the proton-conductive materials.
2. The fuel cell electrode catalyst layer according to claim 1 , wherein the proton-donating group is a sulfonic acid group, and
a dry mass value per mole of the sulfonic acid group in the proton-conductive material in which a dry mass value per mole of the sulfonic acid group is highest among the proton-conductive materials is 1200 g/eq or more.
3. The fuel cell electrode catalyst layer according to claim 1 , wherein the proton-donating group is a sulfonic acid group, and
the proton-conductive materials include a proton-conductive material in which a dry mass value per mole of the sulfonic acid group is 1200 g/eq or more, and
a ratio, with respect to the support, of the proton-conductive material in which the dry mass value per mole of the sulfonic acid group is 1200 g/eq or more is 0.5 or less in a mass ratio.
4. The fuel cell electrode catalyst layer according to claim 1 , wherein the proton-donating group is a sulfonic acid group, and
the proton-conductive materials are composed of: a proton-conductive material in which a dry mass value per mole of the sulfonic acid group is 1200 g/eq or more; and a proton-conductive material in which a dry mass value per mole of the sulfonic acid group is 700 g/eq or less.
5. The fuel cell electrode catalyst layer according to claim 1 , wherein a contact ratio (θ) of the proton-conductive materials with the support is 0.4 or more, the contact ratio (θ) being represented by a following Expression (1):
θ=( C dl _ 30% )/( C dl _ 100% ) (1)
where “C dl _ 30% ” is an electrical double layer capacitance at relative humidity of 30%, and “C dl _ 100% ” is an electrical double layer capacitance at relative humidity of 100%.
6. The fuel cell electrode catalyst layer according to claim 1 , wherein a supported amount of the catalyst is 0.35 mg/cm 2 or less.
7. The fuel cell electrode catalyst layer according to claim 1 , wherein a supported amount of the catalyst is 0.12 mg/cm 2 or less.
8. The fuel cell electrode catalyst layer according to claim 1 , wherein the support is a carbon support, and a specific surface area of the carbon support is 150 m 2 /g or more.
9. The fuel cell electrode catalyst layer according to claim 8 , wherein a contact ratio (θ) of the proton-conductive materials with the carbon support is 0.4 or less, the contact ratio (θ) being represented by a following Expression (1):
θ=( C dl _ 30% )/( C dl _ 100% ) (1)
where “C dl _ 30% ” is an electrical double layer capacitance at relative humidity of 30%, and “C dl _ 100% ” is an electrical double layer capacitance at relative humidity of 100%.
10. The fuel cell electrode catalyst layer according to claim 1 , wherein the support is a carbon support, and a specific surface area of the carbon support is 700 m 2 /g or more.
11. The fuel cell electrode catalyst layer according to claim 10 , wherein a contact ratio (θ) of the proton-conductive materials with the carbon support is 0.35 or less, the coating ratio contact ratio (θ) being represented by a following Expression (1):
θ=( C dl _ 30% )/ ( C dl _ 100% ) (1)
where “C dl _ 30% ” is an electrical double layer capacitance at relative humidity of 30%, and “C dl _ 100% ” is an electrical double layer capacitance at relative humidity of 100%.
12. A fuel cell electrode comprising: the fuel cell electrode catalyst layer according to claim 1 .
13. A fuel cell membrane electrode assembly comprising: the fuel cell electrode catalyst layer according to claim 1 .
14. A fuel cell comprising: the fuel cell membrane electrode assembly according to claim 13 .
15. A fuel cell comprising:
a fuel cell membrane electrode assembly having a fuel cell electrode catalyst layer, the fuel cell electrode catalyst layer comprising a catalyzer comprising:
a catalyst;
a support that supports the catalyst; and
two or more proton-conductive materials different in dry mass value per mole of a proton-donating group, the proton-conductive materials being in contact with at least a part of the catalyst and at least a part of the support, wherein
a proton-conductive material in which a dry mass value per mole of the proton-donating group is highest among the proton-conductive materials is in contact with at least a part of the catalyst, and has a largest contact ratio of the proton-conductive materials with a surface of the catalyst among the proton-conductive materials,
the fuel cell electrode catalyst layer has the catalyzer in a plane of the electrode catalyst layer, and a mass ratio of a proton-conductive material with a low dry mass value per mole of the proton-donating group to a proton-conductive material with a high dry mass value per mole of the proton-donating group differ in portions of the plane of the fuel cell electrode catalyst layer, and
the catalyzer is contained in a manner such that the catalyzer in which a mass ratio of the proton-conductive material with the high dry mass value per mole of the proton-donating group to the proton-conductive material with the low dry mass value per mole of the proton-donating group is large is arranged in a region where relative humidity of gas in a gas flow passage is 90% or more, and the catalyzer in which the mass ratio is small is arranged in a region where relative humidity of gas in the gas flow passage is less than 90%.
16. A fuel cell comprising:
a fuel cell membrane electrode assembly having a fuel cell electrode catalyst layer, the fuel cell electrode catalyst layer comprising a catalyzer comprising:
a catalyst;
a support that supports the catalyst; and
two or more proton-conductive materials different in dry mass value per mole of a proton-donating group, the proton-conductive materials being in contact with at least a part of the catalyst and at least a part of the support, wherein
a proton-conductive material in which a dry mass value per mole of the proton-donating group is highest among the proton-conductive materials is in contact with at least a part of the catalyst, and has a largest contact ratio of the proton-conductive materials with a surface of the catalyst among the proton-conductive materials,
the fuel cell electrode catalyst layer has the catalyzer in a plane of the electrode catalyst layer, and a mass ratio of a proton-conductive material with a low dry mass value per mole of the proton-donating group to a proton-conductive material with a high dry mass value per mole of the proton-donating group differ in portions of the plane of the fuel cell electrode catalyst layer, and
the catalyzer is contained in a manner such that the catalyzer in which a mass ratio of the proton-conductive material with the high dry mass value per mole of the proton-donating group to the proton-conductive material with the low dry mass value per mole of the proton-donating group is large is arranged in a region in a vicinity of a gas discharge port, and the catalyzer in which the mass ratio is small is arranged in a region other than a vicinity of the gas discharge port.
17. The fuel cell electrode catalyst layer according to claim 1 , wherein the electrode catalyst layer is formed on a surface of a polymer electrolyte membrane.
18. The fuel cell electrode catalyst layer according to claim 1 , wherein the two or more proton-conductive materials are concentric.