Thermoelectric properties of rare earths filled CoSb3 based nanostructure skutterudite

Nanostructure engineering and rare earths filling were employed to enhance the thermoelectric properties of the CoSb3 based skutterudite. The CoSb3 and the rare earths filled LaFe3CoSb12, CeFe3CoSb12, La0.5Ce0.5Fe3CoSb12 nano-powders were prepared via a hydro/solvo thermal method and then the nano-powders were used to make bulk samples by hot-press. Our results indicate that besides the nanostructure and the rare earths filling, the existence of a glassy phase in the samples is also an important factor for the enhancement of the thermoelectric properties. The Seebeck coefficients of the samples were improved obviously while their excellent electrical conductivities could be maintained, meanwhile the thermal conductivities of the samples were suppressed significantly. Therefore, the figures of merit were enhanced and ZT values could be reached at 773 K as 0.19, 0.43, 0.62 and 0.82 for CoSb3, LaFe3CoSb12, CeFe3CoSb12 and La0.5Ce0.5Fe3CoSb12 respectively.