Dependence of PEM fuel cell performance on catalyst loading
Abstract
This study focuses on a determination of the cell voltage losses observed for Pt and PtRu loading reductions in H 2/air and reformate/air polymer/electrolyte-membrane fuel cells (PEMFC). Experiments with catalyst-coated membranes (CCM) of varying anode and cathode catalyst loadings with H 2/O 2 and H 2/air demonstrate that the anode catalyst loading in state-of-the-art membrane electrode assemblies (MEAs) operating on pure H 2 can be reduced to 0.05 mg Pt/cm 2 without significant voltage losses, while the cell voltage losses upon a reduction of the cathode catalyst loading from 0.40 to 0.20 mg Pt/cm 2 for optimized MEAs amounts to 10-20 mV, consistent with purely kinetic losses due to the oxygen reduction reaction. It is shown that H 2/air operation with state-of-the-art MEAs very closely approaches the Pt-specific power density (in units of g Pt/kW) for large-scale automotive fuel cell applications with pure H 2 feed. For reformate/air operation, PtRu anode loadings can be reduced to 0.20 mg PtRu/cm 2 for reformate containing 100 ppm CO with a 2% air-bleed. Any further reduction will, however, require either a change in operating conditions (i.e. lower CO concentration or cell temperature ≫80 °C) or novel, more CO-tolerant anode catalysts.
- Publication:
-
Journal of Power Sources
- Pub Date:
- 2004
- DOI:
- 10.1016/j.jpowsour.2003.09.013
- Bibcode:
- 2004JPS...127..162G