A Study on the Changes in Mechanical Properties by the Hydration of Polymer Electrolyte Membrane

Abstract

ZrO2-TiO2 binary oxides with various Zr:Ti molar ratios were prepared by sol-gel method and Nafion Ⓡ /ZrO 2 -TiO 2 composite membranes were fabricated for proton exchange membrane fuel cells (PEMFCs) at high temperature and low humidity. Water uptake, Ion exchange capacity (IEC), and proton conductivity of Nafion Ⓡ /ZrO2-TiO2 composite membranes were characterized and these composite membranes were tested in a single cell at 120℃ with various relative humidity (R.H.) conditions. The obtained results were compared with the unmodified membranes (Nafion Ⓡ 112 and Recast Nafion Ⓡ ). A Nafion Ⓡ /ZrO 2 -TiO 2 composite membrane with 1:3 of Zr:Ti molar ratio showed the highest performance. The performance showed 500 mW/cm 2 (0.499V) at 120℃, 50% R. H., and 2 atm.