Effects of Electroless Plating with Cu Content on Thermoelectric and Mechanical Properties of p-type Bi0.5Sb1.5Te3 Bulk Alloys.

Bi_0.5Sb_1.5Te₃/Cu core/shell powders were prepared by electroless plating and hydrogen reduction, and then sintered into bulk by spark plasma sintering. After electroless plating, with increasing the Cu content, the electrical conductivity keeps enhancing significantly. The highest electrical conductivity reaches 3341S/cm at room temperature in Bi_0.5Sb_1.5Te₃ with 0.67wt% Cu bulk sample. Moreover, the lowest lattice thermal conductivity reaches 0.32 W/m·K at 572.2 K in Bi_0.5Sb_1.5Te₃ with 0.67wt% Cu bulk sample, which is caused by the scattering of the rich-copper particles with different dimensions and massive grain boundaries. According to the results, the ZT values of all Bi_0.5Sb_1.5Te₃/Cu bulk samples have improved in a high temperature range. In Bi_0.5Sb_1.5Te₃ with 0.15wt% Cu bulk sample, the highest ZT value at 573.4 K is 0.81. When the Cu content increases to 0.67wt%, the highest ZT value reaches 0.85 at 622.2 K. Meanwhile, the microhardness increases with increasing the Cu content. [ABSTRACT FROM AUTHOR]