High-efficiency and reliable same-parent thermoelectric modules using Mg ₃Sb ₂-based compounds

ABSTRACT

Thermoelectric modules can convert waste heat directly into useful electricity, providing a clean and sustainable way to use fossil energy more efficiently. Mg ₃Sb ₂-based alloys have recently attracted considerable interest from the thermoelectric community due to their nontoxic nature, abundance of constituent elements and excellent mechanical and thermoelectric properties. However, robust modules based on Mg ₃Sb ₂ have progressed less rapidly. Here, we develop multiple-pair thermoelectric modules consisting of both n-type and p-type Mg ₃Sb ₂-based alloys. Thermoelectric legs based on the same parent fit into each other in terms of thermomechanical properties, facilitating module fabrication and ensuring low thermal stress. By adopting a suitable diffusion barrier layer and developing a new joining technique, an integrated all-Mg ₃Sb ₂-based module demonstrates a high efficiency of 7.5% at a temperature difference of 380 K, exceeding the state-of-the-art same-parent thermoelectric modules. Moreover, the efficiency remains stable during 150 thermal cycling shocks (∼225 h), demonstrating excellent module reliability.

Abstract

The stable-service same-parent all-Mg ₃Sb ₂-based thermoelectric modules provide a fresh perspective for the efficient generation of electricity from low-grade but extremely abundant waste heat.