Enhancement of the thermoelectric performance of SnTe via Mn solubility control

Abstract

Thermoelectric materials have drawn attention due to their capability of directly converting heat and electricity, which helps utilize waste heat and provides an alternative energy source. SnTe is a competitive candidate for thermoelectric performance at medium-high temperature ranges and has become a promising lead-free thermoelectric material. However, the high carrier concentration and thermal conductivity limit its thermoelectric performance and lead to different strategies to enhance its dimensionless figure of merit (zT). Herein, we report an improvement in the thermoelectric performance of SnTe via Ge, Mn, and AgBiSe2 co-alloying. The introduction of AgBiSe2 preliminarily reduces electrical and thermal conductivity, while the co-alloying of Ge and Mn significantly increases the Seebeck coefficient at room temperature and reduces the lattice thermal conductivity. The Sn0.73Ge0.1Mn0.2Te + 3% AgBiSe2 sample exhibits the highest zT of ∼1.44 at 823 K and an average zT of ∼0.71 between 300 and 823 K.