Proton Conduction in Sn[sub 0.95]Al[sub 0.05]P[sub 2]O[sub 7]–PBI–PTFE Composite Membrane

Proton-conducting composite membranes were fabricated by blending having an excess of phosphates with polybenzimidazole (PBI) and polytetrafluoroethylene (PTFE). The addition of PBI to powder stabilized the conductivity of the composite, providing higher conductivities than those of stoichiometric . The addition of PTFE to powder reduced the conductivity but increased the tensile strength. The resulting composite membrane exhibited a conductivity of at and a tensile strength of 2.30 MPa. Moreover, a fuel cell made with this composite membrane yielded high power densities exceeding above and good durability under unhumidified conditions.