고온/저가습 PEMFC 운전을 위한 Nafion^Ⓡ/ZrO_2-TiO_2 복합 전해질 막의 특성 연구

Abstract

ZrO_2-TiO_2 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^Ⓡ/ZrO_2-TiO_2 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.