La1−xSrxFe0.7Ni0.3O3−δ as both cathode and anode materials for Solid Oxide Fuel Cells

Abstract

La1−xSrxFe0.7Ni0.3O3−δ (x = 0, 0.1 and 0.2, LSFNx) are investigated as both cathode and anode materials for Solid Oxide Fuel Cells (SOFCs). The structure, microstructure and electrochemical properties of these materials are studied under oxidizing and reducing atmospheres. In air, the electrodes exhibit polarization resistance of 0.1 Ωcm2 at 800 °C under open circuit voltage. In a H2 atmosphere, Ni nanoparticles are exsolved on the surface, leading to a polarization resistance as low as 0.06 Ωcm2. A cell with a 350 μm thick La0.9Sr0.1Ga0.8Mg0.2O3−δ electrolyte and LSFN electrodes generates a power output of 540 mWcm−2 at 800 °C. Moreover, stable values of power density are obtained after successive oxidation/reduction cycles, confirming the reversibility of the electrodes.