Electrochemical and redox studies of Sm0.5Sr0.5Co1-xNbx (x = 0, 0.1) as cathode materials in intermediate temperature-solid oxide fuel cells

Abstract

The perovskite-oxides, such as (La,Sr)CoO3 and (Ba,Sr)CoO3, have received much attention in recent years as cathode materials for intermediate temperature-solid oxide fuel cells (IT-SOFCs). In this study, we have investigated the structural, electrical, electrochemical, and redox properties of Sm0.5Sr0.5Co1-xNbxO3-δ (SSCNbx) cathodes under conditions relevant to IT-SOFC operation. The SSCNbx (x = 0, 0.1) oxides show gradually decreasing electrical conductivity with increasing Nb doping at the same temperature. The maximum power density of SSCNbx (x = 0.1) is lower than that of SSC; however, SSCNbx (x = 0.1) is more stable than SSC considering the thermodynamic behavior, as determined through redox isotherms. These results suggest that a Nb doped SSC perovskite is suitable, considering its high power density and reasonable redox stability, as an IT-SOFC cathode material.