Exfoliation Route to Nanostructured Cobalt Oxide with Enhanced Thermoelectric Performance

We report on two dimensional (2D)-nanostructured NaxCoO2 with enhanced thermoelectric properties prepared by the exfoliation/restacking method. We have shown that the exfoliation/restacking method is an effective route to constructing nanostructured cobalt oxide. Such a nanostructured sodium cobalt oxide results in an exceptionally low cross-plane conductivity, as low as 0.5 Wm(-1) K-1. Due to the decrease of in-plane thermal conductivity, ZT values of the restacked samples increase in comparison to that of the pristine, which shows the beneficial effect of the nanostructure on the thermoelectric property. (C) 2011 The Japan Society of Applied Physics