Cu_1.8S (digenite), a copper sulfide with natural Cu deficiencies, possesses excellent conductivity, low-cost, as well as environmentally friendly features. It has thus recently attracted heightened attention. However, the thermoelectric performance of pristine Cu_1.8S is poor, and the related mechanical properties have not been deeply investigated, which hinders this material from becoming a candidate for commercial applications. This work proposes an effective approach to synergistically improve the comprehensive performance of polycrystalline Cu_1.8S-based bulk materials for use in practical applications. Cu_1.8S-xRu (x = 0.005, 0.01, 0.02) bulk composites were successfully fabricated by combining mechanical alloying and spark plasma sintering technology. Benefiting from the overall optimized power factor and thermal conductivity by the regulated carrier concentration and enhanced phonon scattering effect from the incorporation of multiscale lattice defects, a peak figure of merit of 1.0 at 773 K was achieved in the Cu_1.8S-1% Ru bulk specimen. In addition, the introduction of ruthenium could enhance the thermal stability of Cu_1.8S materials by suppress the Cu ions motion. A conversion efficiency of 1.0% at a temperature difference of 480 K was obtained for the single-leg TE module. Finally, the excellent average Vickers hardness of 1.22 GPa for the Cu_1.8S-1%Ru bulk composite was higher than that of other state-of-art TE materials. Compositing with ruthenium might be an approach worth promoting to synergistically improve the thermoelectric and mechanical performance of other materials.

Cu _1.8 S (digenite) 是一种天然铜缺乏的硫化铜，具有优良的导电性、低成本和环保特性。因此，它最近引起了高度关注。然而，原始Cu _1.8 S的热电性能较差，相关力学性能尚未深入研究，这阻碍了该材料成为商业应用的候选材料。这项工作提出了一种有效的方法来协同提高多晶 Cu _1.8 S 基块状材料在实际应用中的综合性能。Cu _1.8 S- x Ru ( x = 0.005, 0.01, 0.02) 通过结合机械合金化和放电等离子烧结技术成功地制造了块状复合材料。受益于通过调节载流子浓度实现的整体优化功率因数和热导率，以及通过引入多尺度晶格缺陷增强声子散射效应，在 Cu _1.8 S-1% Ru 块体中实现了 773 K 时的 1.0 峰值品质因数标本。此外，钌的引入可以通过抑制Cu离子运动来增强Cu _1.8 S材料的热稳定性。对于单腿 TE 模块，在 480 K 的温差下获得了 1.0% 的转换效率。最后，Cu _1.8的优异平均维氏硬度为 1.22 GPaS-1%Ru 块状复合材料高于其他最先进的 TE 材料。与钌复合可能是一种值得推广的方法，可以协同提高其他材料的热电和机械性能。