Electrochemical characterization of infiltrated Bi2V0.9Cu0.1O5.35 cathodes for use in low temperature solid oxide fuel cells

The electrochemical performance of porous Bi2V0.9Cu0.1O5.35 (BICUVOX) and BICUVOX-Ce0.9Gd0.1O1.95 (CGO) composite backbones infiltrated with La0.6Sr0.4Co1.05O3-δ (LSC) has been evaluated. LSC was introduced into the screen printed and sintered porous backbones by multiple infiltrations of aqueous nitrate solutions followed by firing. The polarization resistance at 500 °C in air, measured using electrochemical impedance spectroscopy on symmetrical cells of BICUVOX backbones infiltrated with LSC, was approximately 100 times higher than the one obtained for a CGO backbone subjected to the same LSC infiltrations even though the conductivity of BICUVOX at 500 °C was significantly higher than that of CGO at this temperature. The poor performance of the infiltrated BICUVOX backbones is attributed to their coarse microstructure, brought about by the high temperature sintering of the BICUVOX backbone onto the dense CGO electrolyte and a possible reaction layer between the LSC infiltrate material and the BICUVOX backbone. The poor chemical compatibility of BICUVOX with LSC even by using a low temperature processing for the LSC using the infiltration method greatly undermines the motivation to continue the exploration of the combination of these materials for use in solid oxide fuel cells. © 2012 Elsevier B.V. All rights reserved