Study of la4bacu5-xmnxo13+delta materials as potential electrode for symmetrical-sofc
Résumé
La4BaCu5-xMnxO13+δ materials have been synthesized by the sol-gel method in air and studied as possible electrode materials for symmetrical Solid Oxide Fuel Cells (S-SOFC). Within the series, La4BaMn5O13+δ (LBMn) exhibits an excellent stability in reducing atmosphere and remarkable redox stability, although a structure transition from rhombohedral to cubic perovskite structure is found beyond 500 °C in air or wet diluted hydrogen. The thermal expansion coefficients (TEC), deduced from HT-XRD study during redox cycling, make the manganite compatible with classical SOFC electrolytes at low temperature; however, relatively high values of 15.8(5) and 18.1(2) K−1 are found in cathode and anode conditions for T > 500 °C. With high electrical conductivities of 178 and 33.3 S cm−1, in air and hydrogen at 800 °C, we demonstrate that the La0.8Ba0.2MnO3±δ manganite fulfils all the preliminary requirements of an electrode material for symmetrical SOFC.