ABSTRACT Harnessing the potential of thermoelectric technology to convert waste heat into electricity, this study sought to enhance overall energy utilization efficiency and contribute to sustainable development through the advancement of environmentally friendly direct‐conversion materials. Focusing on Cu 3 SbSe 4 ‐based diamond‐like compounds, which are limited by low carrier concentration and high lattice thermal conductivity, we proposed and implemented a synergistic optimization strategy centered on multiscale microstructure engineering. Through employing ternary co‐alloying with Ge, Te, and CuAlSe 2 , a multiscale heterogeneous microstructure comprising point defects, nano‐precipitates, dislocations, and phase boundaries was successfully constructed, which not only enhanced the carrier concentration and optimized the band structure but also enabled full‐spectrum phonon scattering, which dramatically suppressed the lattice thermal conductivity to near its amorphous limit while preserving a comparatively high power factor. Consequently, the optimized material attained a zT of ∼1.38 at 650 K and an average zT avg of ∼0.61, accompanied by significantly enhanced mechanical robustness and thermal stability, thereby demonstrating its promising applicability in mid‐temperature thermoelectric power generation. This work ultimately established an effective paradigm for the synergistic regulation of electrical and thermal transport properties in Cu 3 SbSe 4 ‐based systems via multicomponent alloying.
Wang et al. (Fri,) studied this question.