Impact of the nanostructuring on the thermal and thermoelectric properties of α-SrSi2

Abstract

α-SrSi2 is a promising material for thermoelectric application around room temperature, especially if we can decrease the lattice contribution to the thermal conductivity. We report in this article the effect of the nanostructuring and the effect of the purity on the thermal and thermoelectric properties. Combining ball milling and spark plasma sintering we show that it is possible to obtain nanostructured pellets with grain size about 200 nm which permit to decrease the lattice components to the thermal conductivity close to that expected to highly disordered or amorphous materials. The results obtained in this study also show that the figure of merit ZT is improved after nanostructuring to a value of 0.20 around room temperature. The effect of the Sr purity on the thermoelectric properties is also presented.