Surface micro-etching of Bi2Te3 thermoelectric legs enables a high-efficiency power generator

Abstract

Interface characteristics significantly influence the output performance of thermoelectric power generators, making it crucial to develop cost-effective and straightforward processes for fabricating modules with high bonding strength and low interface contact resistivity. Here, Bi₂Te₃-based materials are treated with a micro-etching method using a mixed acid solution, followed by nickel electroplating and welding with Cu electrodes to assemble the thermoelectric power generator. The micro-etching process induces micropores that create an anchoring effect with the nickel layer, leading to an enhanced tensile strength of ∼9.2 MPa and a reduced interface contact resistivity of ∼4 μΩ cm². As a result, the fabricated Bi₂Te₃ thermoelectric power generator achieves a conversion efficiency of 6.6% and an output power of 0.79 W at a ΔT of 200 K. Furthermore, the module exhibits minimal efficiency and output power loss after aging at 493 K for 700 hours. This work provides a simple yet effective strategy to optimize the performance of Bi₂Te₃-based thermoelectric power generators.