Preparation and Enhanced Thermoelectric Properties of Cu/Bi 0.5 Sb 1.5 Te 3 Composite Materials

The practical application of Bi2Te3 thermoelectric (TE) materials is constrained by their high orientation structure and limited service temperature range. In this work, non-textured Bi0.5Sb1.5Te3 (BST) TE materials were fabricated via a facile, low-cost, and commercially applicable method: cold-pressing combined with annealing. Cu impurity was added into a BST matrix to regulate the carrier concentration and expand the service temperature range. The effects of Cu impurity on the phase composition, microstructure, and TE properties of xCu/BST (x = 0.000%, 0.025%, 0.050%, 0.075%, 0.100%, 0.200% in weight) composite TE materials were investigated. An excellent ZTave value of 0.85 was achieved across the entire temperature range due to synergistic optimization of the electronic and thermal transport properties, which was larger than that of the BST matrix of 0.52 and comparable to that of BST materials prepared by costly and low-yield methods.