Electrode porosity and effective electrocatalyst activity in electrode-membrane-assemblies (MEAs) of PEMFCs
- Institut fuer Chemische Technologie, Darmstadt (Germany)
New production technologies of membrane-electrode-assemblies for PEWCs which ensure almost complete catalyst utilization by {open_quotes}wetting{close_quotes} the internal catalyst surface with the ionomeric electrolyte, allow for a reduction of Pt-loadings from prior 4 mg cm{sup -2} to now less than 0.5 mg cm{sup -2}. Such electrodes are not thicker than from 5 to 10 {mu}m. Little has been published hitherto about the detailed micromorphology of such electrodes and the role of electrode porosity on electrode performance. It is well known, that the porosity of thicker fuel cell electrodes, e.g. of PAFC or AFC electrodes is decisive for their performance. Therefore the issue of this investigation is to measure and to modify the porosity of electrodes prepared by typical MEA production procedures and to investigate the influence of this porosity on the effective catalyst activity for cathodic reduction of oxygen from air in membrane cells. It may be anticipated that any mass transfer hindrance of gaseous reactants into porous electrodes would manifest itself rather in the conversion of dilute gases than in the conversion of pure gases (e.g. neat oxygen). Therefore in this investigation the performance of membrane cell cathodes with non pressurized air had been compared to that with neat oxygen at cathodes which had a relatively low Pt-loading of 0.15 mg cm{sup -2}.
- Research Organization:
- Fuel Cell Seminar Organizing Committee (United States)
- OSTI ID:
- 460297
- Report Number(s):
- CONF-961107-Absts.; ON: TI97001494; TRN: 97:001723-0150
- Resource Relation:
- Conference: Fuel cell seminar, Kissimmee, FL (United States), 17-20 Nov 1996; Other Information: PBD: [1996]; Related Information: Is Part Of Fuel cells seminar; PB: 794 p.
- Country of Publication:
- United States
- Language:
- English
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