This study provides a comparison of different commercially
available
low-cost anion exchange membranes (AEMs), a microporous separator,
a cation exchange membrane (CEM), and an anionic-treated CEM for their
application in the liquid-feed alkaline direct ethanol fuel cell (ADEFC).
Moreover, the effect on performance was evaluated taking two different
modes of operation for the ADEFC, with AEM or CEM, into consideration.
The membranes were compared with respect to their physical and chemical
properties, such as thermal and chemical stability, ion-exchange capacity,
ionic conductivity, and ethanol permeability. The influence of these
factors on performance and resistance was determined by means of polarization
curve and electrochemical impedance spectra (EIS) measurements in
the ADEFC. In addition, the influence of two different commercial
ionomers on the structure and transport properties of the catalyst
layer and on the performance were analyzed with scanning electron
microscopy, single cell tests, and EIS. The applicability barriers
of the membranes were pointed out, and the ideal combinations of membrane
and ionomer for the liquid-feed ADEFC achieved power densities of
approximately 80 mW cm–2at 80 °C.