Effect of Pb(BO[2])[2] Doping on Power Factor of Bi[2]Sr[2]Co[1.8]O[y] Thermoelectric Ceramics

Abstract

In this work, Pb(BO[2])[2]-doped Bi[2]Sr[2]Co[1.8]O[y] thermoelectric materials with composition Bi[2−x][Pb(BO[2])[2]][x]Sr[2]Co[1.8]O[y] (x = 0, 0.075, 0.15, 0.25) were prepared through the solid-state reaction method. Electron transport and microstructural characteristics of prepared materials were studied, and values of their power factor were calculated. It was found that the slight doping of Bi[2]Sr[2]Co[1.8]O[y] with lead borate leads to the decrease in electrical resistivity at 923 K from 126 to 76.5 mΩ cm for x = 0.15. The resistivity increases upon further Pb(BO[2])[2] doping for x = 0.25. The increase in the Seebeck coefficient was observed with an increase in dopant content from x = 0.15 up to 0.25. The Pb(BO[2])[2] doping resulted in a 1.8-fold enhancement of the power factor from 21.7 µW/(m K2) at 923 K in the reference sample to 38.2 µW/(m K{2}) in the doped sample with x = 0.15. Partial substitution of Bi2O3 by Pb(BO2)2 also promotes both grain growth and densification of Bi[2]Sr[2]Co[1.8]O[y] thermoelectric ceramics.