Achieving high thermoelectric performance of Ni/Cu modified Bi0.5Sb1.5Te3 composites by a facile electroless plating

Abstract

Thermoelectric materials have drawn great attention due to their ability to convert heat directly into electricity and vice versa. However, practical applications of thermoelectric materials have been limited by their high cost, low efficiency, and poor mechanical property. To address this issue, we fabricate NiCu/Bi0.5Sb1.5Te3 thermoelectric composites via a facile electroless plating method and spark plasma sintering, which successfully achieve an enhanced peak figure of merit, zT, of ∼1.16 at 425 K for 0.3 wt.%Ni0.15 wt.%Cu/Bi0.5Sb1.5Te3 composites with high average zT of 0.95 in the wide temperature range between 300 and 527 K. Through detailed structural characterization, we found that the plated Cu can be doped into BST matrix and partial Cu/Ni can react with the matrix to form nanoinclusions, which can decouple the interdependent electrical and thermal transport properties, enabling us to achieve synergistic enhancement of zT. This study provides a cheap, simple, fast and effective way to improve the thermoelectric of Bi2Te3-based alloys for high-performance thermoelectric power harvesting and refrigeration.