Advances and challenges for Mg3(Sb,Bi)2-based thermoelectric materials and devices

Abstract

Mg₃(Sb,Bi)₂-based thermoelectric (TE) materials have attracted considerable attention due to their earth-abundant constituent elements, excellent environmental compatibility, and outstanding TE properties in the low- and medium-temperature range. However, optimizing TE properties remains challenging for Mg₃(Sb,Bi)₂, as does device structure design. Given the rapid development of Mg₃(Sb,Bi)₂-based materials and their devices in recent years, there is an urgent need for a systematic and critical review of the progress, challenges, and prospects. We systematically summarize and analyze various current strategies for improving TE properties, including component modulation, defect engineering, band engineering, grain boundary engineering, and mixed scattering optimization of ionized impurities and phonons. In addition, the key challenges for practical applications are comprehensively analyzed, particularly focusing on connection technology, barrier layer material screening, and device structure design. Finally, we outline the significant potential and current challenges of Mg₃(Sb,Bi)₂-based materials in low- and medium-temperature waste heat recovery and solid-state cooling applications, and provide future insights regarding TE properties modulation, preparation scale-up, and novel application prospects.