Scholarly record
ENHANCED POWER FACTOR OF BI2O3 AND BIBO3 CO-SUBSTITUTED CA3CO4OY THERMOELECTRIC CERAMICS
Abstract
Thermoelectricity is a green, renewable energy technology that uses the Seebeck effect to convert waste heat directly into electricity. Cobaltites have great potential for use in thermoelectric generators due to their environmental friendliness, good thermal and chemical stability, and relatively low raw-material costs. Improving the thermoelectric performance of cobaltites using suitable dopants could expand their application potential. This study investigated the effect of bismuth oxide (Bi2O3) and bismuth borate (BiBO3) incorporation on the phase composition, microstructure, and power factor (PF = S^2/Ï) of Ca3Co4Oy cobaltite, where S and Ï represent the Seebeck coefficient and resistivity, respectively. The reference Ca3Co4Oy, Bi2O3-substituted, and Bi2O3/BiBO3 co-substituted samples of Ca3Co4Oy, Ca2.7Bi0.3Co4Oy, Ca2.7Bi0.275Co4(BiBO3)0.025Oy, and Ca2.7Bi0.25Co4(BiBO3)0.05Oy were prepared using the sol-gel method. Phase formation and microstructure were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The Seebeck coefficient and resistivity were measured from 300 to 973 K, and the power factor values were then calculated to assess the thermoelectric performance of the prepared materials. Dual Bi2O3 and BiBO3 incorporation improves the Seebeck coefficient and power factor. The Ca2.7Bi0.275Co4(BiBO3)0.025Oy composition co-substituted with Bi2O3 and BiBO3 showed a 19.3% increase in power factor at 973 K compared to the reference Ca3Co4Oy and Bi-doped Ca2.7Bi0.3Co4Oy compounds.
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References16
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