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.