La1-xSrxFe0.7Ni0.3O3-delta (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 Omega cm(2) at 800 degrees C under open circuit voltage. In a H-2 atmosphere, Ni nanoparticles are exsolved on the surface, leading to a polarization resistance as low as 0.06 Omega cm(2) . A cell with a 350 mu m thick La0.9Sr0.1Ga0.8Mg0.2O3-delta electrolyte and LSFN electrodes generates a power output of 540 mWcm(-2) at 800 degrees C. Moreover, stable values of power density are obtained after successive oxidation/reduction cycles, confirming the reversibility of the electrodes. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.