Preparation, characterization and proton conductivity of membrane based on zirconium tricarboxybutylphosphonate and polybenzimidazole for fuel cells

Zirconium tricarboxybutylphosphonate, Zr(O3PC(CH2)3(COOH)3)2, was synthesized to prepare inorganic/organic composite membranes based on polybenzimidazole (PBI). The characteristics of zirconium tricarboxybutyl-phosphonate (Zr(PBTC)) and of the membranes formed by this and PBI were studied by X-ray diffraction, FTIR, and TG analysis. Both the compacted powers Zr(PBTC) and the Zr(PBTC)/PBI membranes were thermally stable and the conductivities measured on Zr(PBTC) and a sample of the PBI-based membrane with 50 wt.% Zr(PBTC) gave values of 6.74×10−2 and 3.82×10−3 S cm−1 at 200 °C under PH2O/Ps=1, respectively. The treatment to make PBI with characteristic of proton conductivity influenced positively the proton conductivity of PBI-based membrane with 50 wt.% Zr(PBTC). This membrane presented a proton conductivity of 5.24×10−3 S cm−1 under the same measurement conditions.