Polymer Electrolyte Fuel Cells Understanding
the Role of Interfaces for Water Management in Platinum Group
Metal-Free Electrodes in Polymer Electrolyte Fuel Cells Jiangjin
Liu, Morteza Rezaei Talarposhti, Tristan Asset, Dinesh C. Sabarirajan,
Dilworth Y. Parkinson, Plamen Atanassov, and Iryna V. Zenyuk Department of Mechanical Engineering, Tufts University, Medford, Massachusetts 02155, United States National Fuel Cell Research Center, University of California, Irvine, California 92697, United States Department of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, United States Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States Abstract: A
systematic analysis, both experimental and model-assisted, has been
performed over three main configurations of platinum group metal-free
(PGM-free) electrodes in polymer electrolyte fuel cells (PEFCs):
catalyst-coated membrane CCM technology is being compared to the
gas-diffusion electrode (GDE) method of electrode fabrication and
juxtaposed to a hybrid/combined GDE-CCM method of membrane-electrode
assembly (MEA) fabrication. The corresponding electrodes were evaluated
for their electrochemical performance, modeled, and studied with in situ
and operand X-ray computed tomography (X-ray CT). The study establishes
that through-thickness inhomogeneities play the most important role in
water withdrawal/water management and affect most significantly PGM-free
PEFC performance. The catalyst integration technique results in
formation of interfacial regions with increased porosity and surface
roughness. These regions form critical interfaces de facto responsible
for flooding type behavior of the PEFC as shown for a first time by
operando X-ray CT. The computational model shows that the PEFC
performance critically depends on liquid water formation and transport
at cold and wet conditions.   |
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