Highly efficient power generation near room temperature in earth-abundant thermoelectric tin sulfide via lattice ordering

In this work SnS is co-doped with Na and Ag rendering high electric conductivity and Seebeck coefficient while reducing thermal conductivity yielding high thermoelectric performance near room temperature. The study is published in Nature Communications.

The resulting highly metallic conductivity combined with high thermopower yields an ultrahigh room-temperature power factor of ~101 µW cm^-1K^-2 in Sn_0.96Na_0.01Ag_0.03S single crystals. Coupled with the intrinsically low thermal conductivity of SnS, the optimized crystal achieves the figure of merit (zT) of ~1.06 at 300 K and ~2.0 at 573 K, delivering a conversion efficiency of ~3.3% and an output power density of ~0.31 W cm^-2 in a single-leg module under a 243 K temperature gradient.

Detailed characterizations including XRD, Raman spectroscopy, HAADF-STEM, ARPES, XANES, EXAFS, and DFT calculation have been applied to elucidate the lattice and electronic structural modification under the Na and Ag co-doping. Multivalence-band convergence facilitated efficient charge transport in flattened bands rendering strong coupling effect between σ and S in Sn_0.96Na_0.01Ag_0.03S single crystal, enabling the realization of an ultrahigh TE performance at near RT.

“Notably, a high zT peak of ~2 at 573 K was realized within a sulfide-based system, highlighting a significant advance in earth-abundant and environmentally friendly thermoelectrics near RT,” says co-corresponding author Dr. Kuei-Hsien Chen, distinguished research fellow of Institute of Atomic and Molecular Sciences, Academia Sinica and Center for Condensed Matter Sciences, National Taiwan University.

Dr. Kuei-Hsien Chen’s email address: [email protected]