Superior thermoelectric response in the 3R phases of hydrated Na(x)RhO(2)

Density functional theory is used to investigate the thermoelectric properties of the 3R phases of Na(x)RhO(2) for different Na vacancy configurations and concentrations. As compared to the analogous 2H phases, the modified stacking of the atomic layers in the 3R phases reduces the interlayer coupling. As a consequence, the 3R phases are found to be superior in the technologically relevant temperature range. The Rh [Image: see text] orbitals still govern the valence band maxima and therefore determine the transport properties. A high figure of merit of 0.35 is achieved in hydrated Na(0.83)RhO(2) at 580 K by water intercalation, which is 34% higher than in the non-hydrated phase.