Synthesis and electrical properties of Al-doped Sr2MgMoO6-δ as an anode material for solid oxide fuel cells

Aluminum doped Sr2MgMoO6-δ (SMMO) was synthesized via citrate-nitrate route. Dense samples of Sr2Mg1-xAlxMoO6−δ (0 ≤ x ≤ 0.05) were prepared by sintering the pellets at 1500 °C in air and then reducing at 1300 °C in 5%H2/Ar. The electrical conductivity strongly depended on the preparing atmosphere, samples reduced in 5%H2/Ar exhibited higher conductivity than those unreduced. Al-doping increased remarkably the electrical conductivity of Sr2Mg1-xAlxMoO6−δ. The reduced samples displayed a relatively stable electrical conductivity under oxygen partial pressure (Po2) from 10−19 to 10−14 atm at 800 °C, and exhibited an excellent recoverability in electrical conductivity when cycled in alternative air and 5%H2/Ar atmospheres. Sr2Mg0.95Al0.05MoO6−δ material showed a good chemical compatibility with LSGM and GDC electrolytes below 1000 °C, while there was an obvious reaction with YSZ. Al-doping improves the anode performance of SMMO in half-cell of Pt/Sr2Mg1-xAlxMoO6−δ∣GDC∣Pt in H2 fuel. The present results demonstrate that Sr2Mg1-xAlxMoO6−δ is a potential anode material for intermediate temperature-Solid Oxide Fuel Cells (IT-SOFCs).