From the late-1960's, perfluorosulfonic acid (PFSAs) ionomers have
dominated the PEM fuel cell industry as the membrane material of choice.
The "gold standard' amongst the many variations that exist today has
been, and to a great extent still is, DuPont's Nafion(R) family of
materials. However, there is significant concern in the industry that
these materials will not meet the cost, performance, and durability
requirementsnecessary to drive commercialization in key market
segments - es- cially automotive. Indeed, Honda has already put fuel
cell vehicles in the hands of real end users that have home-grown fuel
cell stack technology incorporating hydrocarbon-based ionomers. "Polymer
Membranes in Fuel Cells" takes an in-depth look at the new chem- tries
and membrane technologies that have been developed over the years to
address the concerns associated with the materials currently in use.
Unlike the PFSAs, which were originally developed for the chlor-alkali
industry, the more recent hydrocarbon and composite materials have been
developed to meet the specific requirements of PEM Fuel Cells. Having
said this, most of the work has been based on derivatives of known
polymers, such as poly(ether-ether ketones), to ensure that the critical
requirement of low cost is met. More aggressive operational requi- ments
have also spurred the development on new materials; for example, the
need for operation at higher temperature under low relative humidity has
spawned the creation of a plethora of new polymers with potential
application in PEM Fuel Cells.
