High temperature structural stability, electricalproperties and chemical reactivity ofNdBaCo2xMnxO5+d (0 # x # 2) for use as cathodesin solid oxide fuel cells

International audienceThe effects of Mn substitution for Co on the crystal chemistry, oxygen content, thermal expansion andelectrical conductivity of the NdBaCo2xMnxO5+d perovskites (0 # x # 2) have been investigated. TheNdBaCo2xMnxO5+d samples exhibit structural changes with increasing Mn contents from orthorhombic(x ¼ 0) to tetragonal (0.5 # x # 1) then to cubic (1.5 # x # 2.0) symmetry. All the samples lose oxygenwhen heated in air at T > 400 C although the degree of oxygen loss and kinetics of oxygen exchangebetween the gas phase and oxide decrease with increasing Mn contents. The thermal expansioncoefficients evaluated from ex situ XRD and electrical resistivity decrease with increasing Mn substitutionand the values for the x ¼ 1.5 and 2.0 compositions match with those of the Ce0.8Gd0.2O1.95 (GDC) andLa0.8Sr0.2Ga0.8Mg0.2O2.8 (LSGM) electrolytes. With electrical conductivity values of >100 S cm1 at 800 Cand good chemical stability with GDC and LSGM, the Mn-substituted perovskites are promising cathodematerials for SOFC