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Composite electrodes were prepared by adding 40 wt % La0.8Sr0.2FeO3 (LSF) into porous yttria-stabilized zirconia (YSZ) and their performance was studied as a function of time and calcination temperature. X-ray diffraction (XRD) patterns of the LSF-YSZ composites indicated an expanded lattice parameter after calcination above 1523 K, suggesting that Zr reacted with the LSF to form a Zr-doped perovskite; but XRD provided no evidence for reaction between LSF and YSZ after calcination at 1373 K or after operation for 1000 h at 973 K and 700 h at 1073 K. A composite of 40 wt % La0.8Sr0.2Fe0.9Zr0.1O3 in YSZ showed reasonable performance at 973 K, with an area-specific resistance (ASR) of 0.22 Ω cm2. Based on symmetric-cell measurements, electrodes calcined at 1123 K showed an initial ASR of 0.13 Ω cm2 at 973 K but this increased linearly with time to 0.55 Ω cm2 after 2500 h at 973 K. However, the ASR depended strongly on current density, decreasing dramatically under both anodic and cathodic polarization. Electrodes calcined at 1373 K showed an ASR of 2.5 Ω cm2 at 973 K but this value also decreased dramatically under polarization. Scanning electron microcopy images demonstrate that aging at 973 K and calcination at 1373 K cause significant sintering of the LSF. It is therefore suggested that deactivation is caused by morphological changes, rather than solid-state reactions, with a dense layer of LSF forming over the YSZ substrate.
lanthanum compounds, strontium compounds, yttrium compounds, zirconium compounds, electrodes, composite materials, calcination, lattice constants, electrical resistivity, anodisation, scanning electron microscopy, ageing, current density, sintering, melt infiltration, porous materials, ceramics
Wang, W., Gross, M. D., Vohs, J. M., & Gorte, R. J. (2007). The Stability of LSF-YSZ Electrodes Prepared by Infiltration. Retrieved from https://repository.upenn.edu/cbe_papers/89
Date Posted: 24 May 2007
This document has been peer reviewed.