Effect of B-site doping on the thermoelectric performances of Ca_0.97Y_0.01 La_0.01 Yb_0.01Mn_1-2xNb_xMo_xO_{3 thermoelectric ceramics}

A-, and B -site multiple -doped Ca0.97Y0.01La0.01Yb0.01Mn1-2xNbxMoxO3 was studied for improving its thermoelectric thermoelectric performance. Samples were prepared from planetary milled precursors and sintered at 1310 degrees C for 12 h. XRD showed that sintered samples are nearly single phase, with small amounts of CaMn2O4. SEM analysis revealed that grain size decreases with Nb and Mo content, leading to lowered electrical resistivity, reaching 6.1 mdl cm at 800 degrees C in x = 0.03 samples, 60% lower than that of pristine samples. The highest Seebeck coefficient for doped samples has been obtained for x = 0.005, 210 mu V/K at 800 degrees C. A high power factor (0.46 mW/K2 m at 800 degrees C) has been reached for x = 0.01 samples. However, thermal conductivity did not significantly vary with composition, leading to ZT similar to 0.27 at 800 degrees C for x = 0.005 samples, among the best reported in the literature. These results suggest that multi -doping approach opens new paths for integrating calcium manganitebased materials in thermoelectric modules for power generation at high temperatures.