The concept of a ‘phonon-liquid electron-crystal’ has received significant interest in recent years, with copper selenide (Cu₂Se) emerging as one of the high-performance thermoelectric materials within this framework. This study focuses on the fabrication of Cu₂Se bulk pellets through a low-temperature sintering method known as cold sintering process (CSP). The introduction of a liquid phase (thiol-amine solution) in this process facilitates the dissolution and precipitation of ion/atom clusters, resulting in sample densification. Remarkably, a sample density of nearly 90 % is achieved at a low sintering temperature of only 473 K. Furthermore, this CSP approach preserves the morphology of the Cu₂Se precursor powders and effectively inhibits grain growth. Consequently, the lattice thermal conductivity of the CSP samples is significantly reduced, attributed to enhanced grain boundary phonon scattering. This leads to a substantial improvement in the figure-of-merit (ZT), increasing from 0.65 at 800 K in the hot-pressed sample to 2.13 at 800 K in the CSP sample. The advantages of CSP can be extended beyond Cu₂Se, as it holds promise for enhancing the performance of various high-performance thermoelectric materials.

近年来，“声子液体电子晶体”的概念引起了人们的极大兴趣，硒化铜（Cu ₂ Se）成为该框架内的高性能热电材料之一。本研究重点是通过称为冷烧结工艺 (CSP) 的低温烧结方法制造 Cu _{2 Se 块状颗粒。}在此过程中引入液相（硫醇-胺溶液）有利于离子/原子簇的溶解和沉淀，从而导致样品致密化。_{值得注意的是，在仅 473 K 的低烧结温度下即可实现近 90% 的样品密度。此外，这种 CSP 方法保留了 Cu 2} Se 前驱体粉末的形态并有效抑制了晶粒生长。因此，由于晶界声子散射增强，CSP 样品的晶格热导率显着降低。这导致品质因数 ( ZT ) 显着改善，从热压样品中 800 K 时的 0.65 增加到 CSP 样品中 800 K 时的 2.13。CSP 的优势可以扩展到 Cu ₂ Se 之外，因为它有望提高各种高性能热电材料的性能。