Li-doped Sr2Fe1.5Mo0.5O6–δ as novel symmetrical electrode for solid oxide cells: An insight into the oxygen reduction reaction

For the first time, lithium-doped Sr2Fe1.5Mo0.5O6–δ was synthesized and investigated in terms of its electrochemical behavior. It was found that the use of Li2CO3 as a lithium precursor for the solid-state synthesis of Sr1.9Li0.1Fe1.5Mo0.5O6–δ is ineffective because it results in the formation of a LiFeO2. In contrast, the use of LiNO3 enables the synthesis of single-phase Sr1.9Li0.1Fe1.5Mo0.5O6–δ. Lithium substitution was found to enhance the electrochemical activity of the electrode toward the oxygen reduction reaction. The polarization resistance of Sr1.9Li0.1Fe1.5Mo0.5O6–δ was approximately 0.20 Ohm · cm2 at 800 °C, which is about 1.5 times lower than that of Sr2Fe1.5Mo0.5O6–δ.