On the synthesis and performance of flame-made nanoscale La0.6Sr0.4CoO3-δ and its influence on the application as an intermediate temperature solid oxide fuel cell cathode

Flame spray synthesis (FSS), a large-scale powder processing technique is used to prepare nanoscale La0.6Sr0.4CoO3-delta powder for solid oxide fuel cell cathodes from water-based nitrate solutions. Influence of processing is investigated on basis of the as-synthesised powders by X-ray powder diffraction (XRD), thermal gravimetric analysis (TGA), nitrogen adsorption (BET) and electron microscopy (SEM and TEM). Against the background of a nanostructured cathode morphology for an intermediate temperature solid oxide fuel cell (IT-SOFC) at 600 degrees C, an optimised and high surface area flame-made La0.6Sr0.4CoO3-delta nanopowder of 29 m(2) g(-1) is used to investigate its performance and chemical reaction with common electrolytes (Y0.16Zr0.84O2-delta, Ce0.9Gd0.1O2-delta and Sc0.20Ce0.01Zr0.79O2-delta). Secondary phase analysis from XRD measurements revealed a substantially lower La2Zr2O7 and SrZrO3 formation in comparison to conventional spray pyrolysed and submicron powder of about 9 m(2) g(-1). TGA and resistivity measurements proofed that La0.6Sr0.4CoO3-delta is non-sensitive towards carbonate formation under CO2 containing atmospheres. Electronic bulk conductivity of 2680 S cm(-1) (600 degrees C) and 3340S cm(-1) (500 degrees C) were measured in air and as function of oxygen partial pressure (2 x 10(5) Pa > p(O-2) > 1.2 x 10(-2) Pa) in the temperature range between 400 and 900 degrees C. Electrochemical performance is determined by impedance spectroscopy on symmetrical cells of screen printed nanoscale La0.6Sr0.4CoO3-delta on Ce0.9Gd0.1O2-delta substrates from which an area specific resistance (ASR) of 0.96 Omega cm(2) at 600 degrees C and 0.14 Omega cm(2) at 700 degrees C were obtained. (C) 2010 Elsevier B.V. All rights reserved.