Anion-exchanged porous SnTe nanosheets for ultra-low thermal conductivity and high-performance thermoelectrics

Abstract

Thermoelectric materials with efficient heat-energy conversion have been widely considered as potential electrical energy sources. Herein we propose an anion-exchanged porous SnTe nanosheets (NSs) as a high-performance thermoelectric material with ultra-low thermal conductivity. The solution-phase reaction mechanisms for porous SnTe NSs are proposed, and the reaction conditions are carefully manipulated in order to determine the optimal morphology and excellent thermoelectric performance. The porous SnTe NSs, which consist of extremely small nanoparticles of only ~3 nm in size with defective shapes, lead to a substantial reduction in the lattice thermal conductivity and a higher Seebeck coefficient compared to bulk SnTe, caused by the introduced nanointerfaces, pores and defects. An impressive ZT of ~1.1 at 923 K is achieved without atomic doping process, which is as many as ~2.8 times higher than that of bulk SnTe. This proposed strategy provides an insight to represent an unconventional method for the production of the porous SnTe NSs that can potentially be employed in practical high-performance thermoelectric applications. © 2020 Elsevier B.V.