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2011
Conference Paper
Titel
Microstructure of sol-gel derived nanoscaled La0.6Sr0.4CoO 3-delta cathodes for intermediate-temperature SOFCs
Abstract
Nanocrystalline La 1-xSr xCoO 3-delta (LSC) thin films with a nominal Sr-content of x = 0.4 were deposited on Ce 0.9Gd 0.1O 1.95 electrolyte substrates by low-temperature sol-gel processing. Microstructure, element distribution and electrochemical properties of the LSC thin films were studied after thermal treatment, which included calcination and extended annealing at 700°C or 800°C. Transmission electron microscopy combined with Debye electron diffraction and electron tomography was applied for the investigation of the grain-size distribution and porosity. The local chemical composition and element distribution was analyzed by energy-dispersive X-ray spectrometry on the nanoscale. Area specific polarization resistances as low as 0.023 ohm cm 2 at 600°C were measured applying electrochemical impedance spectroscopy. These low resistance values are facilitated by a substantial increase of the inner surface area of the porous thin-film cathode and amplified by an enhanced surface exchange, resulting from precipitation of Co3O4
Author(s)