Achieving ultrahigh power factor in Mg 3(Sb,Bi) 2-based thermoelectric alloys sintered by introducing elemental Mg and W

• DOI: 10.26599/jac.2025.9221029
• Publication Date: 2025-01-08T01:22:02Z
• Authors: Liangsheng Wang; Shunjian Xu; Jian Yang; Xinyu Tang; Xinyu Wang; Guanjun Qiao; Guiwu Liu
• Keywords: Structural material

Improving the power factor (<em>PF</em>) of thermoelectric materials is crucial for enhancing output density and broadening practical applications. The near-room-temperature electrical performance Mg₃(Sb,Bi)₂-based alloys hindered due to presence Mg vacancies grain boundary scattering, resulting in lower factor. Herein, we introduced an excess into Mg₃(Sb,Bi)₂alloy during hot-pressing process, triggering a liquid phase sintering which can effectively fill increase average size significantly reduce scattering. This leads enhanced room-temperature conductivity (<em>σ</em>) without detrimental effects on Seebeck coefficient (<em>S</em>), thus yielding high <em>PF</em> ~25.3 μW cm^-1 K^-2 figure merit<em> </em>(<em>ZT</em>) ~ 1.03 within temperature range 323‒623 K. Moreover, different amounts W were further added, density-functional theory (DFT) calculations reveal that segregation at boundaries reduces interfacial potential barriers, leading improved <em>S</em> <em>σ</em>. Consequently, ultrahigh ~26.2 was attained W_0.06Mg_3.2Sb_1.5Bi_0.49Te_0.01–4%Mg alloys. Additionally, mechanical properties (Vickers hardness fracture toughness) also compared with pristine </sub>alloy. dual-modified approach boost TE stability, advancing