Selecting the suitable dopants: electronic structures of transition metal and rare earth doped thermoelectric sodium cobaltate

M. H. N. Assadi; S. Li; A. B. Yu

doi:10.1039/C2RA22514J

paper

Selecting the suitable dopants: electronic structures of transition metal and rare earth doped thermoelectric sodium cobaltate

arXiv:1206.5448 · doi:10.1039/C2RA22514J

Abstract

Engineered $N a_{0.75} C o O_{2}$ is considered a prime candidate to achieve high-efficiency thermoelectric systems to regenerate electricity from waste heat. In this work, three elements with outmost electronic configurations, (1) an open d shell (Ni), (2) a closed d shell (Zn), and (3) a half filled f shell (Eu) with maximum unpaired electrons, were selected to outline the dopants' effects on electronic and crystallographic structures of $N a_{0.75} C o O_{2}$ . Systematic $ab$ $ini t i o$ density functional calculations with $D M O L^{3}$ package showed that the Ni and Zn were more stable when substituting Co with formation energy $- 2.35$ eV, $2.08$ eV when Fermi level equals to the valence band maximum. While Eu is more stable when it substitutes Na having formation energy of $- 2.64$ eV. As these results show great harmony with existing experimental data, they provide new insights into the fundamental principle of dopant selection for manipulating the physical properties in the development of high-performance sodium cobaltate based multifunctional materials.

8 pages, 9 figures

References in corpus (1)

Na Induced Correlations in Na $_{x}$ CoO $_{2}$

Selecting the suitable dopants: electronic structures of transition metal and rare earth doped thermoelectric sodium cobaltate

Abstract

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