Effects of Cathode Corrosion on Through-Plane Water Transport in Proton Exchange Membrane Fuel Cells

Date Published
01/2013
Publication Type
Journal Article
Authors
DOI
10.1149/2.024309jes
Abstract

The corrosion of carbon in the cathodes of proton-exchange-membrane fuel cells leads to electrode collapse, reduced active catalyst area, and increased surface hydrophilicity. While these effects have been linked to performance degradation over cell lifetime, the role of corrosion in the evolving water balance has not been clear. In this study, neutron imaging was used to evaluate the through-plane water distribution within several cells over the course of accelerated stress testing using potential holds and square-wave cycling. A dramatic decrease in water retention was observed in each cell after the cathode was severely corroded. The increasing hydrophilic effect of carbon surface oxidation (quantified by ex situ X-ray photoelectron spectroscopy) was overwhelmed by the drying effect of increased internal heat generation. To evaluate this mechanism, the various observed electrode changes are included in a multiphase, non-isothermal one-dimensional cell model, and the simulated alterations to cell performance and water content are compared with those observed experimentally. Simulation results are consistent with the idea that collapse and compaction of the catalyst layer is the dominant limitation to cell performance and not the lower amounts of active Pt surface area, and that higher temperature gradients result in drying out of the cell.

Journal
Journal of the Electrochemical Society
Volume
160
Year of Publication
2013
Issue
9
Pagination
F980 - F993
ISSN Number
0013-4651
Short Title
Journal of the Electrochemical Society
Keywords
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Research Areas
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