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

摘要

Sr- and Mn-doped LaGaO_3 (La_(0.8)Sr_(0.2)Ga_(0.5)Mn_(0.5)O_(3-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 H_2 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℃ of the LSGM electrolyte supported all-perovskite cells can reach 460 mW/cm~2 using wet H_2 as fuel and ambient air as an oxidant. Further, LSGMn anode has showed reasonable sulfur tolerance in H_2-containing 100 ppm H_2S and the all-perovskite cell has demonstrated good performance stability in the short-term operation at a constant cell voltage of 0.7 V.