Dispersion of InSb Nanoinclusions in Cu₃SbS₄ 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 (Cu₃SbS₄) compound is one of the practical substitutes for traditional thermoelectric materials. However, the pristine Cu₃SbS₄ inherits poor structural complexion, large thermal conductivity, and low power conversion efficiency. To develop high-efficiency Cu₃SbS₄, 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 Cu₃SbS₄-3 mol% InSb nanocomposite, which is ≈140% higher than pure Cu₃SbS₄. Both mechanical and thermal stability are improved by grain boundary hardening and dispersion strengthening. Thus, a facile nanostructured Cu₃SbS₄ with added InSb nanoinclusions is delivered as a highly efficient, eco-friendly, structurally-, thermally-, and mechanically-stable material for next-generation thermoelectric generators.