Pack Cementation Route to Ag2Se: Correlating Structure, Phase Formation, and Thermoelectric Performance

Silver selenide (Ag₂Se) is a promising thermoelectric material for near-room-temperature applications, yet its scalable fabrication remains challenging due to limitations in conventional synthesis routes and the strong dependence of its properties on processing conditions. In this work, the pack cementation technique is introduced as a novel cost-effective, and industrially viable route for producing <i>β</i>-Ag₂Se powders. The influence of synthesis parameters on phase formation, composition, and microstructure is examined, and their correlation with thermoelectric behavior is studied to establish clear structure-property relationships. The resulting Ag₂Se is comprehensively evaluated for quality and performance. Phase-pure orthorhombic <i>β</i>-Ag₂Se with near-stoichiometric composition and a uniform microstructure was successfully synthesized, with phase purity preserved after consolidation without secondary phases. The material exhibited competitive thermoelectric performance, achieving a maximum <i>ZT</i> = 0.63 at 352 K and stable operation up to ~375 K. These findings demonstrate that pack cementation can deliver high-quality Ag₂Se with competitive efficiency, highlighting its potential for future optimization and large-scale production.