Phase transition of doped LaFeO₃ anode in reducing atmosphere and their power generation property in intermediate temperature solid oxide fuel cell

In general, transition metal-doped La_0.6Sr_0.4FeO₃ (LSF) has been used as a cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs) because of its high mixed electronic−ionic conductivity and catalytic properties. Recently, some research groups have been investigating the doped LSF as an anode material. In this study, we evaluated the influence of dopant in LSF on anodic properties of LSF in SOFCs. Whereas Mn-doped LSF showed typical perovskite oxide structure even after reduction in hydrogen at high temperature, the LSF and Co-doped LSF exhibited phase transition partially to LaSrFeO₄ and exsolution of metal particles after reduction. The phase transition and metal exsolution occurred at temperature higher than 1008 K in a reducing atmosphere. Despite the partial phase transition, the cell using Co-doped LSF anode exhibited fairly high power density of 1.33 W/cm² at 1173 K with the lowest polarization resistance. These results may originate from the high oxygen-ion conductivity of LaSrFeO₄–La(Sr)Fe(Co)O₃ and the high hydrogen oxidation property of the Co–Fe particles on ceramic anode surface.