Changes In LSC and LSCF Cathode Crystallographic Parameters Measured by Electrochemical In Situ High-Temperature XRD

The solid oxide fuel cell symmetrical cells with porous cathodes for intermediate temperature applications have been studied under electrochemical polarization and oxygen feeding conditions using high-temperature in situ XRD (HT-XRD) method. Changes in the lattice parameters of La0.6Sr0.4CoO3−δ and La0.6Sr0.4Co0.2Fe0.8O3−δ were observed depending on the temperature (T), electrode potential (E) and oxygen partial pressure (pO2) applied. At fixed T and pO2, the cathode potential noticeably influences the crystallographic cell volume calculated, thus, i.e., the oxygen stoichiometry, explained by the partial reduction of electrochemically labile Co-ionic centers in La0.6Sr0.4CoO3−δ (LSC) and the La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) under study. Noticeably higher effect of cathode potential on the cell volume has been established at lower pO2.