Cu_1.8S has been considered as a potential thermoelectric (TE) material for its stable electrical and thermal properties, environmental benignity, and low cost. Herein, the TE properties of nanostructured Cu_1.8S_1−xTe_x (0 ⩽ x ⩽ 0.2) bulks fabricated by a facile process combining mechanical alloying (MA) and room-temperature high-pressure sintering (RT-HPS) technique were optimized via eliminating the volatilization of S element and suppressing grain growth. Experimentally, a single phase of Cu_1.8S was obtained at x = 0, and a second Cu_1.96S phase formed in all Cu_1.8S_1−xTe_x samples when 0.05 ⩽ x ⩽ 0.125. With further increasing x to 0.15 ⩽ x ⩽ 0.2, the Cu_2−zTe phase was detected and the samples consisted of Cu_1.8S, Cu_1.96S, and Cu_2−zTe phases. Benefiting from a modified band structure and the coexisted phases of Cu_1.96S and Cu_2−zTe, the power factor is enhanced in all Cu_1.8S_1−xTe_x (0.05 ⩽ x ⩽ 0.2) alloys. Combining with a drastic decrease in the thermal conductivity due to the strengthened phonon scatterings from multiscale defects introduced by Te doping and nano-grain boundaries, a maximum figure of merit (ZT) of 0.352 is reached at 623 K for Cu_1.8S_0.875Te_0.125, which is 171% higher than that of Cu_1.8S (0.130). The study demonstrates that doping Te is an effective strategy to improve the TE performance of Cu_1.8S based materials and the proposed facile method combing MA and RT-HPS is a potential way to fabricate nanostructured bulks.

Cu _1.8 S由于其稳定的电学和热学性质，环境友好性和低成本而被认为是潜在的热电（TE）材料。在本文中，纳米结构的Cu的TE特性_1.8小号_{1- X}特_X（0⩽ X ⩽0.2）块材制造用的简便工艺相结合机械合金化（MA）和室温高压烧结（RT-HPS）技术进行了优化通过消除S元素的挥发并抑制晶粒长大。实验上，在x = 0时获得了单相Cu _1.8 S ，在所有Cu _1.8 S _{1- x中}形成了第二个Cu _1.96 S相。特_X样品时0.05⩽ X ⩽0.125。随着x进一步增加到0.15 x 0.2，将检测到Cu _{2- z} Te相，样品包括Cu _1.8 S，Cu _1.96 S和Cu _{2- z} Te相。从修改的带结构和Cu的共存相受益_1.96 S和铜_{2- Ž}碲，功率因数增强所有的Cu _1.8小号_{1- X}特_X（0.05⩽ X⩽0.2）合金。结合由于Te掺杂和纳米晶界引入的多尺度缺陷引起的声子散射增强而导致的导热率急剧下降，对于Cu _1.8 S _0.875 Te _0.125，在623 K时，最大品质因数（ZT）为0.352。，比Cu _1.8 S（0.130）高171％。研究表明，掺杂Te是提高Cu _1.8 S基材料的TE性能的有效策略，而提出的将MA和RT-HPS结合起来的简便方法是一种制备纳米结构体的潜在方法。