Enhanced Thermoelectric and Mechanical Properties of n-type Bi2Te2.7Se0.3 Bulk Alloys by Electroless Plating with Cu

Abstract

Bi2Te2.7Se0.3/Cu core/shell powders were prepared by electroless plating and hydrogen reduction, and then sintered into bulk by spark plasma sintering in order to improve the thermoelectric and mechanical properties of n-type Bi-Te thermoelectric material. After electroless plating, with the increasing of Cu content, Seebeck coefficient keeps increasing and power factor enhances significantly. The highest power factor increases by three times and reaches 23.8 W·cm−1·K−2 at room temperature in Bi2Te 2.7Se0.3 with 0.22wt% Cu sample, which means electrical transport properties of Bi2Te2.7Se0.3/Cu samples have been improved. Meanwhile, the ZT values of Bi2Te2.7Se0.3/Cu samples can be enhanced at different temperature zone by adjusting the Cu content. Bi2Te2.7Se0.3 with 0.05wt% Cu sample has the best thermoelectric properties in high temperature zone, and the ZT peak value increases from 0.35 to 0.85 at 623 K. When the Cu content increases to 0.15wt%, the ZT peak value moves to the low temperature (373 K) and increases from 0.24 to 0.71. At the same time, the mechanical properties increases with the increasing of Cu content.