Simultaneous enhancement of thermoelectric and mechanical performance in Ag2Se via Sb2Te3 compositing

Silver Selenide (Ag2Se) has been deemed as an excellent candidate for substitution of the n-type Bi2Te3 for thermoelectric applications. However, the naturally high electron concentration resulting from interstitial cation and inferior mechanical performance of pristine Ag2Se significantly limit its practical application. Additionally, the conventional synthesis of Ag2Se commonly requires complex and time-consuming high temperatures melting or ball milling processes. In this study, Ag2Se composited with Sb2Te3 was synthesized through a simple manual mixing followed by a hot press sintering method. By introducing microparticle Sb2Te3, the carrier concentration of Ag2Se was suppressed and thus the Seebeck coefficient and Hall mobility were enhanced simultaneously. Furthermore, the presence of particulate Sb2Te3 and the interfaces formed between Ag2Se and Sb2Te3 intensified phonon scattering and impeded crack propagation. These lead to a suppression in thermal conductivity accompanied by an improvement in hardness. Consequently, an enhanced zT of 0.92 and an improved hardness of 71 Kgf center dot mm(-2) were achieved for Ag2Se composited with 2 mol% and 3mol% Sb2Te3, which were approximately 30 % and 18 % higher than those of the pristine Ag2Se, respectively. These results indicate that combining manual mixing with the introduction of secondary-phase particles provides a facile approach to simultaneously optimize both the thermoelectric and mechanical performance of Ag2Se.