AgSbSe2 inclusions enabling high thermoelectric and mechanical performance in n-type Ag2Se-based composites

Ag2Se is a promising near-room-temperature thermoelectric material with prospective applications in solid-state cooling and waste heat recovery. To advance the practical application of Ag2Se, it is imperative yet challenging to further boost its average dimensionless figure of merit (zT) and mechanical performance. Herein, we effec-tively enhance the two types of performance by constructing Ag2Se/AgSbSe2 composite architectures with uniform distribution of AgSbSe2 inclusions, which was realized by sintering solution-synthesized mixtures of Ag2Se nano/micro-particles and Sb2Se3 nanorods. Particulate AgSbSe2 and as-built Ag2Se/AgSbSe2 interfaces enable intensified phonon scattering and impeded crack propagation, and refined grain size additionally con -tributes to optimized thermal and mechanical properties. As a result, (Ag2Se)0.98(2AgSbSe2)0.02 composite ap-proaches a low lattice thermal conductivity of 0.15 W m-1 K-1 at 375 K and an excellent average zT of-0.89 between 300 and 375 K; mechanically, this composite obtains a compressive strength of 197.3 MPa, which is improved by-125% compared to that of Ag2Se and represents the highest value ever reported for this com-pound. This study sheds light on the efficacy of introducing secondary-phase particles on simultaneously boosting the thermoelectric and mechanical performance of Ag2Se.

Automated summary

In this study, Ag2Se/AgSbSe2 composite architectures were constructed with uniform distribution of AgSbSe2 inclusions, which effectively enhanced the thermoelectric and mechanical performance of Ag2Se. The composite material exhibited low lattice thermal conductivity, excellent average zT, and significantly improved compressive strength. This research provides new insights into simultaneously boosting the thermoelectric and mechanical performance of Ag2Se by introducing secondary-phase particles.