Oxide anode derived from Sr-doped LaMnO ₃ perovskite oxide for SOFCs using LaGaO ₃ electrolyte

Various oxides were investigated as a ceramic anode of solid oxide fuel cells (SOFCs) using LaGa O3 -based oxide electrolyte. It was found that the cell using Sr-doped LaMn O3 for anode exhibits a fairly large power density among the examined oxides for anode. Because the anodic overpotential as well as the electrical resistance decreased, the power density of the cell increased with increasing the amount of Sr doped for La site in LaMn O3, and the highest power density of the cell was obtained by using La0.5 Sr0.5 Mn O3 for anode. On this cell, the maximum power density was achieved to a value of 0.64 and 0.25 W cm2 at 1273 and 1073 K, respectively. After exposure of the cell to air at 1273 K for 24 h, almost the same power density was recovered by changing air to H2. X-ray diffraction measurement suggests that the perovskite phase of La0.5 Sr0.5 Mn O3 anode partially decomposed into La2 Mn O4, Mn O2, and SrMn O3 after the power generation measurement; however, small power density can only be achieved on the cell using Mn O2, SrMn O3, La2 Mn O4, and LaSrMn O4 for anode. Therefore, LaMn O3 perovskite phase doped with Sr is active as the anode of SOFCs, which is highly tolerant against oxidation.