Electrochemical performance of Sr1.9La0.1Fe1.5Mo0.5O6-δ symmetric electrode for solid oxide fuel cells with carbon-based fuels

La-doped Sr 2-x La x Fe 1.5 Mo 0.5 O 6-δ perovskite oxides are synthesized and used as a symmetric electrode to evaluate the effect of La on the crystal structure, conductivity, and catalytic activity for O 2 reduction and H 2 oxidation reaction. The electronic doping effect dominates the oversize effect in Sr 2-x La x Fe 1.5 Mo 0.5 O 6-δ oxide, resulting in unit cell volume expansion and decreased conductivity in air. In addition, the introduction of La increases the chemical structural stability of Sr 2 Fe 1.5 Mo 0.5 O 6-δ in reducing condition due to the higher La–O bond compared with Sr–O bond, leading to high catalytic activity for the H 2 oxidation reaction. At 800 °C, the R p values of Sr 1.9 La 0.1 Fe 1.5 Mo 0.5 O 6-δ symmetric cell in air and wet H 2 are as low as 0.075 and 0.21 Ω cm 2 , respectively. Moreover, the peak power densities of 769, 561, 439, and 653 mW cm −2 at 850 °C are obtained when wet H 2 , CO, CH 4, and C 3 H 8 are used as fuels on Sr 1.9 La 0.1 Fe 1.5 Mo 0.5 O 6-δ /LSGM/Sr 1.9 La 0.1 Fe 1.5 Mo 0.5 O 6-δ cell. The symmetric cell also shows excellent stability (>100 h) in wet H 2 /air, implying Sr 1.9 La 0.1 Fe 1.5 Mo 0.5 O 6-δ oxide is a promising symmetric electrode material .