NAMS 2002 Workshop - ICOM 2008

Fuel Cells III – 4
Friday July 18, 4:00 PM-4:30 PM, Moloka’i
Novel Electrolytes for Fuel Cell Electrodes
J. Muldoon (Speaker), Toyota Motor Engineering & Manufacturing North America, Inc., Ann
Arbor, Michigan, USA - john.muldoon@tema.toyota.com
R. Wycisk, Case Western Reserve University, Cleveland, Ohio, USA
J. Lin, Case Western Reserve University, Cleveland, Ohio, USA
P. Pintauro, Case Western Reserve University, Cleveland, Ohio, USA
K. Hase, Toyota Motor Corporation, Japan
Fuel cells (FC) are attracting great attention due to their high energy conversion
efficiency and low pollution emission, relative to conventional combustion
engines. Among various types, proton exchange membrane fuel cells (PEMFC)
have emerged as promising power generators for portable, stationary, and
automotive applications. For hydrogen/air and direct methanol fuel cells, a typical
electrode binder is a perfluorsulfonic acid polymer such as Nafion" (DuPont)
which shows exceptional chemical stability, good mechanical strength, high
proton conductivity, and high gas permeability (oxygen/hydrogen). Unfortunately,
Nafion" is very expensive and poses a serious environmental threat of HF
release upon its decomposition under FC operating conditions and during
recycling of the catalyst, which would be avoided if a non-fluorinated polymer
were used. Polyphosphazenes are an attractive class of polymers with a
backbone composed of alternating phosphorus and nitrogen atoms. Through
appropriate functionalization of the backbone, the properties of these polymers
can be designed to an extent unachievable with other types of materials. Here
we report on the preparation and fuel cell performance of catalyst inks containing
sulfonated polyphosphazenes. The method of preparing membrane-electrodeassemblies
with polyphosphazene-based binders will be described and the
resulting hydrogen/air fuel cell performance plots will be contrasted to those
obtained with Nafion as the electrode binder.