Tuesday, 3 October 2017: 08:30
Chesapeake 12 (Gaylord National Resort and Convention Center)
Polybenzimidazole (PBI) polymers are excellent candidates for PEM fuel cell membranes capable of operating up to 200˚C. Several years ago, we developed a sol-gel process to produce PBI membranes loaded with high levels of phosphoric acid. This process, termed the PPA process, uses polyphosphoric acid as the condensing agent for the polymerization and the membrane casting solvent. Membranes produced from this process showed the ability to maintain high levels of phosphoric acid (PA) and high proton conductivities while simultaneously exhibiting low levels of PA loss during operation. We have been exploring the effects of chemical structure on the basic membrane properties, as well as issues of membrane stability and durability. We will describe some of our recent results on the correlations between polymer structure and properties which provide valuable insights for designing membranes with extended durability tailored to fuel cells. Additionally, the synthetic variability in preparing many different PBI polymers has provided several opportunities to tailor the PBI chemistry to a growing number of devices related to energy and separations applications. PBI membranes have been prepared which were designed for hydrogen "pumping", the hybrid-sulfur cycle, and flow batteries. Recent results in these areas will be presented.