Electrocatalytic Properties of Intermediate Temeprature-SOFC Cathode/LSGMC Interfaces

Electrocatalytic properties of the interfaces between La 0 8Sr0 2Ga0 8Mg0 115Co 0 085O3-δ (LSGMC) electrolyte and various cathodes: comprised of Sm0 5Sr0 5CoO3-δ (SSC), and La0 7Sr0 3Co0 2Fe0 8O 3-δ (LSCF) in composite forms (70wt.%) with LSGMC (30wt.%) were investigated under both oxygen reduction and evolution conditions. All the oxides were synthesized using the glycine-nitrate process (GNP). Symmetrical electrochemical cells were investigated with three-electrode linear dc polarization and ac impedance spectroscopy. For the composite SSC-LSGMC cathode/LSGMC interface, the cathodic overpotential under 1 A/cm2 current density was as low as 0.085 V at 700°C, 0.062V at 750°C and 0.051V at 800°C in air. Composite LSCF-LSGMC cathode/LSGMC interfaces were found to have about twice the exchange current density of composite SSC-LSGMC/LSGMC interfaces at 700°C © The Electrochemical Society.