(277b) Composite Polybenzimidazole/Polyimide-Clay-H3po4 Membranes for Use in Fuel Cell Applications

Proton exchange membranes (PEMs) have been prepared using an inorganic/polymer composite membrane. These membranes were formed from polybenzimidazole (PBI) / phosphotungstic acid and commercial polyimide (kapton) / clay-H3PO4. Proton conductivity was measured using AC impedance spectroscopy. A Nyquist plot is generated which shows both real and imaginary resistances. The conductivity is determined from the real resistance. The membrane with 20% wt phosphotungstic acid in PBI was characterized and the proton conductivity was 1.7 x 10-6 S.cm-1 at room temperature and 100% relative humidity. The membrane with 20% wt clay-H3PO4 in commercial polyimide (kapton) has been characterized and it gave proton conductivity of 1.8 x 10-3 S.cm-1 at room temperature and 90% relative humidity. Current synthesis involves the use of supramolecular chemistry for enhanced proton conductivity through the formation of pores and channels in the membrane.