Colossal Thermoelectric Power Factor in K$_{7/8}$RhO$_2$
Abstract
We discuss the thermoelectric and optical properties of layered K$_{x}$RhO$_{2}$ (\emph{x} = 1/2 and 7/8) in terms of the electronic structure determined by first principles calculations as well as Boltzmann transport theory. Our optimized lattice constants differ significantly from the experiment, but result in optical and transport properties close to the experiment. The main contribution to the optical spectra are due to intra and interband transitions between the Rh 4\emph{d} and O 2\emph{p} states. We find a similar power factor for pristine K$_{x}$RhO$_{2}$ at low and high cation concentartions. Our transport results of hydrated K$_{x}$RhO$_{2}$ at room temperature show highest value of the power factor among the holetype materials. Specially at 100 K, we obtain a value of 3$\times$10$^{3}$ K$^{1}$ for K$_{7/8}$RhO$_{2}$, which is larger than that of Na$_{0.88}$CoO$_{2}$ {[}M. Lee \emph{et al}., Nat. Mater. 5, 537 (2006){]}. In general, the electronic and optical properties of K$_{x}$RhO$_{2}$ are similar to Na$_{x}$CoO$_{2}$ with enhanced transport properties in the hydrated phase.
 Publication:

arXiv eprints
 Pub Date:
 November 2013
 arXiv:
 arXiv:1311.3402
 Bibcode:
 2013arXiv1311.3402S
 Keywords:

 Condensed Matter  Materials Science
 EPrint:
 Adv. Funct. Mater. 22, 2792 (2012)