Triazole and triazole derivatives as proton transport facilitators in polymer electrolyte membrane fuel cells

Some basic aspects pertaining to the application of triazole and its derivatives as proton transport facilitators for membranes for high temperature fuel cell operations are investigated. Performance as proton transport facilitators is studied for compounds in their native solid state and as a dopant in a polymer membrane. Some key parameters which influence the proton transport in the system are the proton affinity, pKa or acidity, activation energy and the ease of formation of hydrogen bonding network. Theoretical calculations of the proton affinity of the compounds are presented. The effect of proton affinity of the compound on the activation energies for proton transport is investigated. Proton conductivity is measured for acid doped triazoles in both pellet form (powder triazole mixed with acid) and in composite forms wherein the acid group is contained in a polymer matrix. The effect of formation of a hydrogen bonding network by the triazoles and its impact on the proton conductivity are studied. Also, the effect of ion exchange capacity (IEC) of the host polymeric electrolytes and loading of triazoles in the composites were investigated.