An insight into β-Zn4Sb3 from its crystal structure, thermoelectric performance, thermal stability and graded material

Abstract

Thermoelectric (TE) materials have emerged as promising alternative for environment-friendly applications, being used for solid state power generator and heating/cooling to address environmental issues such as the global warming and the limitations of energy resources. Excellent TE materials should possess low thermal conductivity and high power factor, simultaneously. β-Zn4Sb3 is a p-type intermetallic compound, which is endowed with “phonon glass, electron crystal” (PGEC) behavior, exhibiting high Seebeck coefficient and low thermal conductivity close to the limit of amorphous structure. Due to its high TE performance, β-Zn4Sb3 is considered to be a promising TE material in the intermediate range of 500–750 K. In particular, remarkable advances have been recently achieved in the β-Zn4Sb3 TE material by introduction of nano-structures to tune the transport of phonons and electrons. However, its poor thermal stability is the obstacle to commercial application at the operating temperature. To understand the intrinsic nature of β-Zn4Sb3, such as crystal structure and structural variations with temperature, can help to develop appropriate strategies to enhance its TE performance and thermal stability. In this review, we shed light on the β-Zn4Sb3 TE material in details from several key aspects such as crystal structure, TE performance, thermal stability and the novel in-situ graded material. Finally, we propose the strategies for improving the TE performance and thermal stability of β-Zn4Sb3.