Electrochemical Investigation of Composite Cathodes with SmBa0.5Sr0.5Co2O5+δ Cathodes for Intermediate Temperature-Operating Solid Oxide Fuel Cell

The electrochemical characteristics of the samarium and strontium doped layered perovskite (SmBa1−xSrxCo2O5+δ, x = 0.5) have been investigated for possible application as a cathode material for an intermediate temperature-operating solid oxide fuel cell (IT-SOFC). The cathodic polarization of single-phase and composite cathodes with 10 mol % gadolinia-doped ceria (Ce0.9Gd0.1O2−δ, CGO91) shows that a weight ratio between SmBa0.5Sr0.5Co2O5+δ (SBSCO) and CGO91 of 1:1 (50 wt % SBSCO and 50 wt % CGO91, SBSCO:50) gives the lowest area specific resistance (ASR) of 0.10 Ω cm2 at 600 °C and 0.013 Ω cm2 at 700 °C. The maximum and minimum electrical conductivity in SBSCO are 1280 S cm−1 at 50 °C and 280 S cm−1 at 900 °C, with the influence of oxygen partial pressure indicating p-type conduction. The maximum power density of SBSCO:50 in an anode supported SOFC was 1.31 W cm−2 at 800 °C and 0.75 W cm−2 at 700 °C.