Solid State Ionics, Vol.181, No.23-24, 1119-1124, 2010
Effect of Ni content on the microstructure and electrochemical properties of Ni-SDC anodes for IT-SOFC
Ni-SDC (samaria-doped ceria) films for an IT-SOFC anode were fabricated by a slurry spin coating method. The microstructure and electrochemical performances of the Ni-SDC anodes were investigated with respect to the Ni vol.%. The connectivity of Ni-Ni grains, SDC-SDC grains and Ni-SDC grains, which is remarkably influenced by the Ni vol.%, is suggested to dominate the electrochemical behavior of the Ni-SDC anodes, including a hydrogen adsorption/diffusion process on the surface of Ni particles and a charge transfer process on the SDC electrolyte. A porous microstructure consisting of homogeneously distributed Ni and SDC phases together with well-connected grains was observed for the Ni-SDC anodes containing 50% and 60% volume content of Ni, which exhibited a polarization resistance around 0.1 Omega cm(2) together with an overpotential around 30 mV under a current density of 200 mA cm(-2) at 800 degrees C in a 60%N-2+40%H-2 atmosphere. (C) 2010 Elsevier B.V. All rights reserved.
Keywords:Slurry spin coating;Three electrode half cell;Hydrogen adsorption/diffusion;Charge transfer;Overpotential