A composite anode composing of in-situ exsolved Fe-Ni alloy (FNA) nanoparticles and Ruddlesden-Popper perovskite SrLaFeO4 (SLF) substrate has been prepared by reducing La0.5Sr0.5Fe0.8Ni0.20O3-delta(LSFN) perovskite precursor in humidified H-2 (3% H2O) at 800 degrees C. Roles of FNA and SLF, respectively, in performance and stability of the anode are systematically studied. The electric conductivity of the reduced LSFN and single cell performance of the composite (SLF-FNA) are examined in comparison with those of the SrLaFeO4-delta(SLFO4) anode alone. The significantly improved performance of the composite anode cell at lower temperatures (<700 degrees C) maybe predominately ascribed to the enhanced electrochemical activity as well as electric conductivity due to the presence of FNA exsolution. The maximum power densities (PmaxS) of a single cell with the composite anode achieve 0.74, 0.58, 0.40, and 0.25 W cm(-2) at 800, 750, 700 and 650 degrees C, respectively, which is comparable to the performance of Fe-Ni-SDC cermets anode. However, the long time stability of the composite anode is superior to that of the Fe-Ni-SDC cermets in various fuels, suggesting that SLF-FNA is sulfur tolerant and coking-tolerant composite anode material, which possess great potentials for future application. The results can be used as guidance for designing high-performance composite anodes for intermediate temperature solid oxide fuel cells (IT-SOFCs). (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.