Dispersion of InSb nanoinclusions in Cu${}_3$SbS${}_4$ for improved stability and thermoelectric efficiency

Thermoelectric-based waste heat recovery requires efficient materials to replace conventional non-eco-friendly Te- and Pb-based commercial devices. Ternary copper chalcogenide-based famatinite (Cu${}_3$SbS${}_4$) compound is one of the practical substitutes for traditional thermoelectric materials. However, the pristine Cu${}_3$SbS${}_4$ inherits poor structural complexion, large thermal conductivity, and low power conversion efficiency. To develop high-efficiency Cu${}_3$SbS${}_4$, InSb nanoinclusions are incorporated via high-energy ball milling followed by the hot-press densification method. Incorporating InSb nanoinclusions to lower thermal conductivity via phonon scattering while increasing the thermopower via a carrier energy filtering process. The thermoelectric performance (ZT) of ≈0.4 at 623 K is obtained in Cu${}_3$SbS${}_4$-3 mol% InSb nanocomposite, which is ≈140% higher than pure Cu${}_3$SbS${}_4$. Both mechanical and thermal stability are improved by grain boundary hardening and dispersion strengthening. Thus, a facile nanostructured Cu${}_3$SbS${}_4$ with added InSb nanoinclusions is delivered as a highly efficient, eco-friendly, structurally-, thermally-, and mechanically-stable material for next-generation thermoelectric generators. (© 2023 The Authors. Advanced Energy and Sustainability Research published by Wiley‐VCH GmbH)