Properties and Performance of Anode-Supported Proton-Conducting BaCe0.48Zr0.4Yb0.1Co0.02O3-delta Solid Oxide Fuel Cells

The anode-supported BaCe0.48Zr0.4Yb0.1Co0.02O3-delta (BCZYC2)-based proton-conducting solid oxide fuel cells (H+-SOFCs) were fabricated using dual layer tape casting technique. BCZYC2 is a phase pure cubic perovskite and is stable in both humidified H-2 and CO2 at 973 K. The total dc conductivity of BCZYC2 measured in humidified H-2 was 2.1 X 10(-3) S/cm at 873 K. The cell performance was measured with humidified H-2 fuel and methanol/water fuel [with varying molar steam:carbon (S:C) ratios] at 873 K. The maximum open-circuit potential (OCP) of 1.04 V was achieved at 873 K in 3% humidified H-2 fuel with an accompanying peak power density of 89 mW/cm(2). The total cell polarization resistance was 0.83 Omega cm(2). Impedance measurements showed decreasing polarization and ohmic resistance with increasing current density. The cell operation via internal steam reforming of methanol was demonstrated using a methanol/water feed with 3:1 and 2:1 S:C ratios; however, the OCP was reduced to 0.97 and 0.95 V and the peak power density decreased to 65 and 58 mW/cm(2), respectively. This was primarily attributed to a lower H-2 concentration in the feed stream. (C) 2010 The Electrochemical Society. [DOI:10.1149/1.3467840] All rights reserved.