High entropy phenomena induced low thermal conductivity in BiSbTe1.5Se1.5 thermoelectric alloy through mechanical alloying and spark plasma sintering

Abstract

The facile synthesis approach combining the mechanical alloying (5 h) and spark plasma sintering (SPS) (11 min) of BiSbTe1.5Se1.5 high entropy alloy (HEA) is reported. High entropy engineering and nanostructuring phenomena synergistically lower the lattice thermal conductivity (<0.2 W/mK) and thermal diffusivity (<0.5 mm2/s) thus results in ultralow thermal conductivity (0.667 W/mK) at 523 K. The synthesized nanostructured HEA offers good power factor (5.51 × 10−4 W/mK2) and figure of merit (ZT) of 0.43 at 523 K.