Symmetrical solid oxide fuel cells with impregnated SrFe0.75Mo0.25O3−δ electrodes

Here we report nominally symmetrical solid oxide fuel cells that feature thin La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) electrolytes and impregnated SrFe0.75Mo0.25O3−δ (SFMO)-LSGM composite electrodes. Operation on hydrogen fuels and air oxidants can produce maximum power densities of 0.39 W cm−2 at 650 °C and 0.97 W cm−2 at 800 °C. Impedance measurements indicate that the anode and the cathode polarizations are 0.22 and 0.04 Ω cm2 at 800 °C, respectively. Hydrogen partial pressure and temperature dependence of impedance data in humidified hydrogen shows that hydrogen oxidation kinetics is largely determined by hydrogen adsorption on the SFMO catalysts at high temperatures and charge transfer reactions along the SFMO|LSGM interfaces at low temperatures. Carbon tolerance of the present fuel cells is also examined in iso-octane fuels balanced by nitrogen at 800 °C that yields stable maximum power densities of 0.39 W cm−2.