Ultra-fast Synthesis of Cu2S Thermoelectric Materials under Pulsed Electric Field

Abstract

Cu2S shows excellent thermoelectric properties as a material with phonon liquid-electron crystal characteristics. However, traditional preparation methods are cumbersome and difficult to afford bulk Cu2S with uniform composition, high density and excellent thermoelectric properties. In this study, a novel method named Pulsed Electric Current Sintering was introduced to synthesize and sinter Cu2S materials in one step consuming only 30 s. The synthesis of Cu2S under intense pulsed electric field includes three steps. A small amount of CuS and Cu2S forms in the first step; most of Cu2S and part of Cu1.96S are produced in the second step; finally, the remained Cu1.96S and Cu react to form completely pure Cu2S. The Cu2S bulk obtained by this method is a dense bulk with homogeneous composition, and contained abundant multi-scale microstructures. The thermoelectric performance is optimized by regulation of Cu-deficient Cu2-xS. The maximum ZT of Cu1.97S bulk at 873 K is 0.72, which is 49% higher than that of the pristine sample.