Sahu, A.K. and Selvarani, G. and Pitchumani, S. and Sridhar, P. and Shukla, A.K.
(2007)
A Sol-Gel Modified Alternative Nafion-Silica Composite
Membrane for Polymer Electrolyte Fuel Cells.
Journal of the Electrochemical Society, 154 (2).
B123-B132.
ISSN 0013-4651
Abstract
Nafion-silica composite membranes are fabricated by embedding silica particles as inorganic fillers in perfluorosulfonic acid
ionomer by a novel water hydrolysis process. The process precludes the use of an added acid but exploits the acidic characteristic
of Nafion facilitating an in situ polymerization reaction through a sol-gel route. The use of Nafion as acid helps in forming
silica/siloxane polymer within the membrane. The inorganic filler materials have high affinity to water and assist proton transport
across the electrolyte membrane of the polymer electrolyte fuel cell �PEFC� even under low relative humidity �RH� conditions. In
the present study, composite membranes have been tested in hydrogen/oxygen PEFCs at varying RH between 100 and 18% at
elevated temperatures. Attenuated total reflectance-Fourier transform infrared spectroscopy and scanning electron microscopy
studies suggest an evenly distributed siloxane polymer with Si–OH and Si–O–Si network structures in the composite membrane.
At the operational cell voltage of 0.4 V, the PEFC with an optimized silica–Nafion composite membrane delivers a peak power
density value five times higher than that achievable with a PEFC with conventional Nafion-1135 membrane electrolyte while
operating at a RH of 18% at atmospheric pressures.
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