| dc.description.abstract | Hydrogen/air fuel cells are a clean-energy alternative to the internal combustion engine in
automotive vehicles. This type of fuel cell utilizes the chemical potential between hydrogen
and oxygen to generate electricity, with water as the by-product. A significant barrier to largescale commercialization of fuel cell electric vehicles is the costly platinum catalyst needed to
facilitate the electrochemical reaction. Herein, we discuss the use of electrospinning
particle/polymer fibers to produce highly porous fuel cell electrodes with a high surfac e area.
These fibrous electrodes increase platinum availability and are appreciably more resistant to
degradation than conventional spray electrodes. Specifically, this work discusses:
(1) Improved power production using a platinum-nickel alloyed cathode catalyst, which is
inherently more active towards the oxygen reduction reaction than pure platinum. PtNi/C fiber
cathodes membrane-electrode-assemblies (MEAs) exhibited high power at both high and low
operating humidity and retainedg0% of beginning-of-life power after 30,000 load cycles.
(2) The production of fiber electrodes with a neat Nafion binder. This was achieved by
spinning with Na*-form Nafion and poly(ethylene oxide), the latter of which was removed via
awater wash. Neat-Nafion fiber MEAs exhibited increased power output and, surprisingly,
significantly improved performance at low operating humidity due to capillary condensation
of water in small pores.
(3) The use of higher platinum loading cathodes in fiber mat MEAs for heavy duty vehicle
applications. By altering the electrode processing, high cathode loadings lead to improve
power and durability.
(4) Examination of water distribution profiles in an operating fuel cell MEA via neutron
scattering experiments with both spray and fiber mat electrodes. It was confirmed that, at high
operating humidity, fiber electrode MEAs held less water than spray electrode MEAs. | |
