Strontium- and Manganese-Doped Lanthanum Gallate as a Potential Anode Material for Intermediate-Temperature Solid Oxide Fuel Cells

Abstract

Sr- and Mn-doped LaGaO3 (La0.8Sr0.2Ga0.5Mn0.5O3−δ, LSGMn) has been synthesized using a glycine nitrate combustion method. Powder X-ray diffraction examinations show that the synthesized LSGMn has a pure single cubic perovskite phase. Four-probe direct current conductivity characterization indicates that the conductivity of the sintered LSGMn in wet H2 is lower than that in air, whereas the activation energy in wet H2 is higher than that in air. Such an expected p-type conduction mechanism is the result of the valence change of Mn, which enables LSGMn to be a mixed ionic and electronic conductor. Using LSGMn as an anode and LSCF as a cathode, the peak power density at 800°C of the LSGM electrolyte supported all-perovskite cells can reach 460 mW/cm2 using wet H2 as fuel and ambient air as an oxidant. Further, LSGMn anode has showed reasonable sulfur tolerance in H2-containing 100 ppm H2S and the all-perovskite cell has demonstrated good performance stability in the short-term operation at a constant cell voltage of 0.7 V.