4,5-dicyano-1H-[1,2,3]-triazole as a proton transport facilitator for polymer electrolyte membrane fuel cells

High proton conductivity with limited or no dependence on humidity is the desired property for proton exchange membrane for use in a fuel cell operating above 100 degrees C. Proton exchange facilitators are designed to aid in transport of protons at low humidity conditions by acting as a proton bridge. The presence of intermolecular hydrogen bonding in these compounds leads to the formation of a proton conducting network where the proton hopping is enabled by the amphoteric nature of these neutral molecules. We report 4,5-dicyano-1H-[1,2,3]-triazole (DCTz) as an active proton transport facilitator for PEM fuel cells. We observe conductivities on the order of 1 mS/cm in dry conditions at 100 degrees C for composites of DCTz with polyacrylonitrile in the absence of any external proton sources. High acidity of N-H proton as well as existence of a hydrogen-bonded network in DCTz leads to facile proton transport through the membrane in the absence of humidity. Diffusion measurements from NMR experiments further confirm the existence of local proton conducting structures over the long range. Electrochemical stability of DCTz in the potential window of interest offers additional advantage for the use of this material in PEM fuel cells.