Solid oxide fuel cells with Sm0.2Ce0.8O2-δ electrolyte film deposited by novel aerosol deposition method

In this study, dense electrolyte ceramic Sm0.2Ce0.8O2-delta (SDC) thin films are successfully deposited on NiO-SDC anode substrate by aerosol deposition (AD) with oxygen as the carrier gas at the substrate temperature ranging from room temperature to 300 degrees C. To remove the effect of humidity on the starting powders, this study found that, in depositing SDC films, having the starting powders preheat-treated at 200 degrees C helped generate a smooth and dense layer, though a lower deposition rate was achieved. At a deposition time of 22 min, SDC films with a uniform thickness of 1.5 mu m and grain sizes of approximate to 67 nm are obtained. SOFC single cells are then built by screen printing a LSCF cathode on the anode-supported substrates with SDC electrolyte. The cross-sectional SEM micrographs exhibit highly dense, granular, and crack-free microstructures. The open circuit voltages (OCV) of the single cells decrease with the rise in temperature, dropping from 0.81 Vat 500 degrees C to 0.59 V at 700 degrees C. Maximum power densities (MPD) decline with decreasing operating temperature from 0.34 to 0.01 W cm(-2) due to the increase of the R-0 and R-P of the single cells. The electrochemical results testify to the fine quality of SDC films as well as illustrate the electrolyte thickness effect and the effect of mixed ionic and electronic conduction of the SDC electrolyte in the reducing atmosphere. (C) 2011 Elsevier B.V. All rights reserved.