The Stability of LSF-YSZ Electrodes Prepared by Infiltration

Abstract

Composite electrodes were prepared by adding (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 , 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 or after operation for at and at . A composite of in YSZ showed reasonable performance at , with an area-specific resistance (ASR) of . Based on symmetric-cell measurements, electrodes calcined at showed an initial ASR of at but this increased linearly with time to after at . However, the ASR depended strongly on current density, decreasing dramatically under both anodic and cathodic polarization. Electrodes calcined at showed an ASR of at but this value also decreased dramatically under polarization. Scanning electron microcopy images demonstrate that aging at and calcination at 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.