NAMS 2002 Workshop - ICOM 2008

Fuel Cells III – 5
Friday July 18, 4:30 PM-5:00 PM, Moloka’i
Effect of Hydrocarbon Ionomer on Electrochemical Performance of MEA for
Direct Methanol Fuel Cell (DMFC)
S. Lee (Speaker), School of Chemical Engineering, Hanyang University, Korea
C. Lee, School of Chemical Engineering, Hanyang University, Korea
Y. Lee, School of Chemical Engineering, Hanyang University, Korea - ymlee@hanyang.ac.kr
Direct methanol fuel cells (DMFCs) have been receiving much attention as clean
and alternative energy source owing to high energy efficiency and excellent
power density. The fuel cell performances are significantly affected by
electrochemical properties of membrane-electrode assemblies (MEAs) where the
electrochemical reactions take a place at the three-phase boundary zone
consisting of catalyst, catalyst binder and proton exchange membrane (PEM).
Hear, a catalyst binder acts as proton conductor as well as a mechanical
supporter in the catalyst layer. The binder also contributes to enhanced
dispersion of catalyst. A high-performance electrode requires good adhesion
between the membrane and electrode, uniform catalyst dispersion in the
electrode and good ion conduction. These properties are influenced by the
component materials and fabrication process of the electrode. In most cases,
Nafion® ionomer (EW=1,100) has been used as catalyst binder, irrespective of
membrane materials. A severe delamination in MEAs occurred between low-cost
hydrocarbon membrane and Nafion® ionomer owing to incompatibility between a
catalyst binder and a membrane material. MEA containing hydrocarbon
membrane needs a new hydrocarbon catalyst binder to reduce interfacial
resistance with catalyst layers. Unfortunately,only a little attention has been paid
so far to the catalyst binder compatible with the alternative electrolyte
membranes. In this study, a new type of hydrocarbon binder (B1) was designed
to fabricate a desirable MEA based on sulfonated polymer membrane. The
effects of B1 binder on MEA properties and also on its electrochemical cell
performance are investigated.