Properties of 10% Dy-doped La2Mo2O9 and its electrolyte performance in single chamber solid oxide fuel cell

Abstract

Abstract To explore plausible applications of 10 mol% Dy-doped La 2 Mo 2 O 9 (LDM), we have prepared membrane-electrode assemblies (MEAs) based on this oxide ion conductor and operated them under single chamber conditions of methane and air. Material selection is centered on matching thermal expansion of the LDM electrolyte, joined with an anode support of nickel and ceria cermet and a graded cathode of samarium strontium cobaltite plus ceria. The performance test results indicate that both open circuit voltage and ohmic loss increase with increasing LDM thickness, leading an optimal LDM thickness 60 μm. This MEA of 60 μm thick LDM generates peak power 330 mW cm −2 at 700 °C, which can be upgraded to 420 mW cm −2 through promoting the anode activity. Impedance analysis indicates the electrode improvements are effective, but have limitations, because the major polarization loss resides in the LDM electrolyte. High electrolyte polarization loss originates from two weaknesses of LDM, excessive thermal expansion and vulnerability to hydrogen reduction.