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

Abstract

Engineered $N{a}_{0.75}Co{O}_2$ 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 $N{a}_{0.75}Co{O}_2$. Systematic $ab$ $initio$ density functional calculations with $DMO{L}^3$ 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 (6)

• Charge-ordering, commensurability and metallicity in the phase diagram of layered Na(x)CoO(2)
• The crystal growth and characterization of NaxCoO2 and NaxCoO2yH2O
• Na Induced Correlations in Na${}_x$CoO${}_2$
• Infrared spectroscopy of the charge ordering transition in Na${}_{0.5}$CoO${}_2$
• Drastic ground state changes induced by Ni substitution in NaxCoO2
• Effect of Ti doping on the electrical transport and magnetic properties of layered compound Na0.8CoO2

Cited by in corpus (4)

• Restoration of long range order of Na ions in $N{a}_{x}Co{O}_2$ at high temperatures by sodium site doping
• Interplay between Magnetism and Na concentration in $N{a}_{x}Co{O}_2$
• Dopant incorporation site in sodium cobaltate's host lattice: A critical factor for thermoelectric performance
• Magnetic, electrochemical and thermoelectric properties of $P2-N{a}_x(C{o}_{7/8}S{b}_{1/8})O_2$