| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Engineering Ceramics: Microstructure-Property-Performance Relations and Applications
|
| Presentation Title |
Impact of Mixed Valence Dopants and Related Grain Boundary Segregation on the Seebeck Coefficient of Ca3Co4O9 Ceramics |
| Author(s) |
Geoffroy Gauneau, Cesar-Octavio Romo-de-la-Cruz, Fuming Jiang, Yun Chen, Xueyan Song |
| On-Site Speaker (Planned) |
Geoffroy Gauneau |
| Abstract Scope |
We have previously demonstrated that oversized dopants segregate at the grain boundaries of Ca3Co4O9 ceramics and lead to a dramatic increase in the Seebeck Coefficient. The dominance of the ionic size factor on the dopants' grain boundary segregation could be complicated for the mixed valent dopants such as Sm. Sm presents as an oversized dopant for Ca when Sm is divalent and an undersized dopant when Sm is trivalent. Our present work shows that an increase of Sm doping in both Ca3Co4O9Smx (x=0.00, 0.05, 0.10, 0.20) with Sm addition and Ca3-xSmxCo4O9+δ (x=0.00, 0.05, 0.10, 0.15, 0.30) with Sm substitution has led to the increase of Seebeck coefficient. The Seebeck coefficient of Ca3Co4O9 ceramics was further increased with the simultaneous incorporation of dual dopants Bi and Sm. The impact of the chemistry stoichiometry and dual dopants on the valence state of Sm and its related grain boundary segregation was systematically analyzed. |