Improved Methanol Permeability for Direct Methanol Fuel Cells

"The purpose of the proposed OSD Phase I program is to develop and commercialize ion-conducting thermally stable polymers for use as high temperature proton exchange membrane/membrane electrode assemblies (PEM/MEA) materials with low methanol permeabilityas components of direct methanol fuel cells (DMFC). Polymer electrolyte/proton exchange membrane (PEM) fuel cell systems are an environmentally friendly power source for a wide range of applications that include transportation (cars and buses), stationary(home power generation), and consumer electronics (computers and phones). Sulfonated ion-conducting sites will be introduced via direct polymerization, allowing control of both their location and concentration. Preliminary work has indicated that the PIand colleagues are capable of synthesizing such materials exceeding the conductivity and methanol permeability performance of perfluorinated sulfonic acid Nafion materials at, or above, room temperature. These new sulfonated copolymers show no change incell resistance over a period of one month at a hydrogen/air delivery pressure of 30psig at 80¿C under fully humidified conditions. Additionally, cast films of the novel copolymers demonstrated a marked (nearly four-fold) decrease in methanol permeability(fuel cross-over), which could greatly limit flooding, and the decreased efficiency associated with this phenomenon. These new materials also are much less costly than fluoropolymers