Synthesis and high temperature thermoelectric properties of Yb0.25Co4Sb12-(Ag2Te)x(Sb2Te3)1−x nanocomposites

摘要: Nanocomposites are becoming a new paradigm in thermoelectric study: by incorporating nanophase(s) into bulk matrix, nanocomposite often exhibits unusual properties beyond its constituent phases. To date most nanophases binary, while reports on ternary nanoinclusions scarce. In this work, we conducted an exploratory study of introducing (Ag2Te)x(Sb2Te3)1-x inclusions the host matrix Yb0.25Co4Sb12. Yb0.25Co4Sb12 - 4wt% nanocomposites were prepared melting-milling-hot-pressing process. Microstructural analysis showed that poly-dispersed nanosized Ag-Sb-Te distributed grain boundaries coarse grains. Compared to pristine nanoinclusion-free sample, electrical conductivity, Seebeck coefficient, and thermal conductivity optimized simultaneously upon nanocompositing, carrier mobility was largely remained. A maximum ZT 1.3 obtained Yb0.25Co4Sb12-4wt% (Ag2Te)0.42(Sb2Te3)0.58 at 773 K, ~ 40% increase compared sample. The electron phonon mean-free-path estimated help quantify observed changes lattice conductivity.