Characterization of La_(0.8)Sr_(0.2)(Co,Cu,Fe)O3 Perovskites as a Cathode Contact Material for Solid Oxide Fuel Cells

摘要

Perovskites resulting from discrete changes in composition within the quasi-ternary system La_(0.8)Sr_(0.2)CuO_(2.4+δ)-La_(0.8)Sr_(0.2)CoO_(3-δ)-La_(0.8)Sr_(0.2)FeO_(3-δ) were investigated under similar experimental conditions for the first time with the objective of obtaining an overview of the variation of the relevant properties for possible applications as cathode contact layer in SOFCs. Nineteen perovskite compositions within this system were systematically selected and synthesized under identical conditions by the Pechini method. The distribution of the different crystallographic phases at 1050oC within this quasi-ternary phase diagram, the DC electrical conductivity at 800oC and the thermal expansion coefficients are presented. High densification was obtained in compositions containing Cu. The highest conductivity is obtained for La_(0.8)Sr_(0.2)CoO_(3-δ) with 1350 S cm~(-1) and the highest thermal expansion for La_(0.8)Sr_(0.2)Co_(0.75)Fe_(0.25)5O3 with 18 x 10~(-6) K~(-1).^