Fuel Cell Membrane Polymer Degradation Mechanisms by Density Functional Theory

Utterbeck, Kimberly, and Jonathan Stevens

~~Polymer Electrolyte Membrane Fuel Cells (PEFMC’s), or simply “Fuel Cells,” are expected to continue to play a role in the development of applied alternative energy sources.  Sulfonated polyether (ether) ketone, or sulfonated PEEK (sPEEK) membranes are one possible candidate for fuel cell membranes, however, the chemical stability of such membranes needs to be explored further in the presence of H radicals in order to make a better assessment. Our group’s research in molecular orbital /density functional calculations aims to study the attack of H radicals on sPEEK1, a derivative of the sPEEK molecule. Our study of sPEEK thus far has illustrated that H radicals readily attach to the aryl rings of sPEEK polymers. The effect of H radical attachment to sPEEK was further studied by finding the transition states and associated energetics of bond breaking reactions of C-S and C-O occurring after the radicals attach. The barriers associated with the breaking of these bond are not high, and therefore bond breaking is likely to occur, especially at the C-S bond location.