High figures of merit and natural nanostructures in Mg_2Si_(0.4)Sn_(0.6) based thermoelectric materials

摘要

Mg_2(Si,Sn) compounds have shown great promise for thermoelectric applications due to good thermoelectric properties, nontoxicity, and abundantly available constituent elements. Herein we report on the thermoelectric properties and microstructure of high performance Mg_2Si_(0.4-x)Sn_(0.6)Sb_x (0≤x≤0.015) alloys. The state-of-the-art ZT value of ～ 1.1 has been attained in the samples with x=0.0075 due to the relatively low thermal conductivity. In light of the simple cubic structure and mostly light constituent elements, the reduction in lattice thermal conductivity has been discussed in connection with a fairly large amount of in situ formed nanostructures in these samples.