This project seeks to develop a new class of proton exchange membranes for use in fuel cells at temperatures up to 120 °C. Whereas the industry standard for such membranes is sulfonated Nafion, fuel cells using that material are limited to significantly lower temperatures of 80 °C and high humidity because liquid water entrapped in the membrane is necessary for proton conductivity. We propose new materials that use acid-base complexation between phosphoric acid and an amphoteric polymer such as poly(ethylene oxide) (PEO) or others to provide the proton conductivity, and no water will be required. PEO domains will be dispersed in a high-temperature stable aromatic polyimide that will provide mechanical support for the PEO, which melts at 65 °C. New polymers will be synthesized, fabricated into membranes, and characterized for their proton conductivity as a general screen. High conductivity membranes will be additionally characterized using small-angle X-ray scattering at SSRL and small-angle neutron scattering at NIST to determine the optimum morphology of the multi-phase system.
Curtis W. Frank, Department of Chemical Engineering, Stanford and Michael Toney, Stanford Synchrotron Radiation Lightsource, SLAC
http://news.stanford.edu/news/2010/may/precourt-research-grants-050410.html