Properties of La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) double layer cathodes on gadolinium-doped cerium oxide (CGO) electrolytes - I. Role of SiO2

Abstract

Investigations using Gd-doped CeO2 electrolytes containing different levels of SiO2, in combination with La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF) electrodes, have shown that the SiO2 can influence both the electrolyte and cathode resistivities. The cathode resistivity, as measured by AC impedance spectroscopy, was further reduced by fabricating an intermediate thin dense LSCF layer at the electrolyte/electrode interface. Etching the electrolyte surface to eliminate the influence of SiO2, and using the thin dense interfacial layer, made it possible to obtain cathode area specific resistivities (ASR) as low as 0.5 Omega cm(2) at 520 degrees C.