Characterization of the 75% Gd0.8Sr0.2CoO3−δ/25% Ce0.9Gd0.1O2−δ composite cathode system for use in intermediate temperature solid oxide fuel cells

The composite cathode system is examined for suitability on a Ce0.9Gd0.1O2−δ electrolyte based solid oxide fuel cell at intermediate temperatures (500–700 °C). The cathode is characterized for electronic conductivity and area specific charge transfer resistance. This cathode system is chosen for its excellent thermal expansion match to the electrolyte, its relatively high conductivity (115 S cm−1 at 700 °C), and its low activation energy for oxygen reduction (99 kJ mol−1). It is found that the decrease of sintering temperature of the composite cathode system produces a significant decrease in charge transfer resistances to as low as 0.25 Ω cm2. The conductivity of the cathode systems is between 40 and 88 S cm−1 for open porosities of 30–40%.