|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Alloys and Compounds for Thermoelectric and Solar Cell Applications IV
||Enhancement of Thermoelectric Performance Calcium Cobaltite through Cation Grain Boundary Segregation
||Xueyan Song, Cullen Boyle, Paulo Carvillo, Yun Chen, Ever Barbero, Dustin McIntyre, Paul Barnes
|On-Site Speaker (Planned)
We report the increase of the Seebeck coefficient S and thermoelectric performance of Ca3Co4O9 ceramics through both non-stoichiometric addition of Ba and stoichiometric substitution of Bi, resulting in the high ZT values of 0.52 at 1073 K for Ca3Ba0.05Co4O9 and 0.43 at 1083 K for Ca2.8Bi0.2Co4O9.
Nanostructure examinations show that Ba segregated at Ca3Co4O9 grain boundaries while grain interior is free of Ba. Conversely, dopant Bi in Ca3-yBiyCo4O9 presents both in grain interiors and boundaries. Enhancement of S is attributed to the carrier filtering effect caused by the segregation of dopants at the grain boundaries of Ca3Co4O9. Furthermore, dopant segregation promotes better crystal alignment and development of crystal texture. Additionally, dopants as defect may cause disorder and structural distortion and therefore suppress the phonon transport. This study opens the new directions and revolutionizes our ability to control grain boundaries for enhancing the thermoelectric properties of oxide ceramic.
||Planned: A print-only volume