Electrical transport properties of Ca0.9La0.1-xBixMnO3-δ (0 ≤ x ≤ 0.1) thermoelectric materials

A series of Ca0.9La0.1-xBixMnO3-delta (0 <= x <= 0.1) was fabricated by cold compaction and tape casting methods. The microstructural and thermoelectric properties of Ca0.9La0.1-xBixMnO3-delta were studied, with respect to the partial substitution of Bi3+ for La3+. All of the sintered Ca0.9La0.1-xBixMnO3-delta crystallized in the orthorhombic perovskite structure, belonging to the Pnma space group. The substituted Bi3+ significantly increased grain size and density because it acted as a sintering additive. The electrical conductivities of tape casting-processed Ca0.9La0.1-xBixMnO3-delta were much higher than those of cold compactionprocessed Ca0.9La0.1-xBixMnO3-delta. On the other hand, the absolute values of the Seebeck coefficient for tape casting-processed Ca0.9La0.1-xBixMnO3-delta were similar to those of cold compaction-processed Ca0.9La0.1-xBixMnO3-delta. Consequently, tape casting-processed Ca0.9La0.1-xBixMnO3-delta showed a much higher power factor in comparison with cold compaction-processed Ca0.9La0.1-xBixMnO3-delta. The partial substitution of La3+ by Bi3+ up to x = 0.05 led to an increase in the power factor. The highest power factor (3.01 x 10(-4) Wm(-1).K-2) was obtained for tape casting-processed Ca0.9La0.1-xBixMnO3-delta at 800 degrees C. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.