Enhanced Thermoelectric and Mechanical Properties of p-type Bi_0.5Sb_1.5Te₃ Bulk Alloys by Composite Electroless Plating with Ni&Cu

Abstract

In order to improve the thermoelectric and mechanical properties of p-type Bi₂Te₃ thermoelectric material, Bi_0.5Sb_1.5Te₃/Ni&Cu core/shell powders were electroless plated with the same content of Ni and different content of Cu, and then reduced by hydrogen, and finally sintered into bulk by spark plasma sintering. After composite electroless plating with Ni&Cu, for the bulk sample with 0.3 wt% Ni and 0.15 wt% Cu, the power factor rises significantly and the highest value increases from 25 to 33 µW·cm⁻¹·K⁻² at room temperature. Meanwhile, the thermal conductivity decreases to about 0.80 W·m⁻¹·K⁻¹ at 623 K. Therefore, the composite electroless plating with Ni&Cu can obviously improve the electrical and thermal transport performance of p-type Bi₂Te₃ based thermoelectric materials. Thus, the ZT value enhances significantly and the highest value increases over 3 times, from 0.35 to 1.16 at 473 K in Bi_0.5Sb_1.5Te₃ with 0.3 wt% Ni and 0.15 wt% Cu bulk sample. At the same time, the mechanical properties have also been improved after composite electroless plating with Ni&Cu.