NEW PEM FUEL CELL MEMBRANES FOR HIGHER TEMPERATURE, DRIER OPERATING CONDITIONS BASED ON THE HETEROPOLYACIDS

We are developing new proton exchange membranes for hotter and drier operating conditions in fuel cells. The materials we are developing are based on the interaction between the heteropolyacids (HPAs) and the proton donating groups in polymers. One set of materials are composite membranes taking advantage of the HPAs and perfluorosulfonic acid (PFSA) ionomers. These composite membranes have superior proton conductivity compared to the native ionomer under hotter and drier conditions and additionally appear to be more durable under the harsh oxidizing environment of the PEM fuel cell. In another set of materials HPAs are functionalized with monomers which are co-polymerized with monomers that donate protons and add structural features to the hybrid films. While we are yet to fabricate a "polyPOM" with superior proton conductivity these materials can be made to conduct protons as well as standard PFSAs without the need for sulfonic acids.