Fuel cell electrodes using high density support material
Methods of preparing fuel cells and fuel cell electrodes having catalyst with high density catalyst support are provided. One method of fabricating a fuel cell electrode comprises adjusting the gravimetric ratio of ionomer to catalyst support based on the density of the support material to optimize ionomer performance.
1. A method of fabricating a fuel cell electrode comprising:
setting a target volumetric ratio of an ionomer to a high density catalyst support by:
selecting a desired gravimetric ratio of the ionomer to a reference catalyst support and calculating a corresponding volumetric ratio of the ionomer to the reference catalyst support; and
setting the target volumetric ratio to the corresponding volumetric ratio;
determining a relationship between a gravimetric ratio and a volumetric ratio for the high density catalyst support;
from the target volumetric ratio and the relationship, calculating a target gravimetric ratio of the ionomer to the high density support;
preparing the catalyst ink from a mass of the ionomer and a mass of the hi g h density support based on the target gravimetric ratio of the ionomer to the high density support; and
coating the catalyst ink onto a membrane to form a catalyst layer on the membrane.
2. The method of claim 1 , wherein the high density support consists essentially of one or more metal oxides.
3. The method of claim 2 , wherein the one or more metal oxides are selected from MnO x , CuO, ZnO, FeO x , Cr 2 O 3 , TiO 2 , SnO 2 , Nb 2 O 5 , WO 3 , In 2 O 3 , Sb 2 O 3 , CeO 2 and RuO 2 , composites thereof and alloys thereof.
4. The method of claim 1 , wherein the high density support consists essentially of titanium dioxide and ruthenium dioxide.
5. The method of claim 1 , wherein the reference catalyst support is a carbon catalyst support.
6. The method of claim 1 , wherein the relationship between a gravimetric ratio and a volumetric ratio is based on density.
7. The method of claim 1 , wherein the relationship between a gravimetric ratio and a volumetric ratio is based on morphology.
8. The method of claim 1 , wherein the relationship between a gravimetric ratio and a volumetric ratio is based on porosity.
9. A fuel cell assembly comprising the membrane prepared according to claim 1 , wherein the catalyst layer comprises the ionomer and the high density support, and an amount of ionomer in the catalyst layer is determined from the tar g et gravimetric ratio of the ionomer to the high density support.
10. A method of manufacturing a fuel cell comprising:
preparing a catalyst ink comprising:
setting a target volumetric ratio of an ionomer to a high density catalyst support by:
selecting a desired gravimetric ratio of the ionomer to a reference catalyst support and calculating a corresponding volumetric ratio of the ionomer to the reference catalyst support; and
setting the target volumetric ratio to the corresponding volumetric ratio;
determining a relationship between a gravimetric ratio and a volumetric ratio for the high density catalyst support; and
from the target volumetric ratio and the relationship, calculating a target gravimetric ratio of the ionomer to the high density support;
preparing the catalyst ink comprising active catalyst particles, the high density support and the ionomer according to the target gravimetric ratio of the ionomer to the high density support; and
coating the catalyst ink onto a membrane.
11. The method of claim 10 , wherein the high density support consists essentially of one or more metal oxides.
12. The method of claim 11 , wherein the one or more metal oxides are selected from MnO x , CuO, ZnO, FeO x , Cr 2 O 3 , TiO 2 , SnO 2 , Nb 2 O 5 , WO 3 , In 2 O 3 , Sb 2 O 3 , CeO 2 and RuO 2 , composites thereof and alloys thereof.
13. The method of claim 10 , wherein the high density support consists essentially of titanium dioxide and ruthenium dioxide.
14. The method of claim 10 , wherein the reference catalyst support is a carbon catalyst support.
15. The method of claim 10 , wherein the relationship between a gravimetric ratio and a volumetric ratio is based on density.
16. The method of claim 10 , wherein the relationship between a gravimetric ratio and a volumetric ratio is based on morphology.
17. The method of claim 10 , wherein the relationship between a gravimetric ratio and a volumetric ratio is based on porosity.
18. A fuel cell stack comprising a plurality of fuel cells manufactured according to claim 9 .