Realizing a Superior Conversion Efficiency of ≈11.3% in the Group IV-VI Thermoelectric Module

GeTe-based materials exhibit superior thermoelectric performance, while the development of power generation devices has mainly been limited by the challenge of designing the interface due to the phase transition in GeTe. In this work, via utilizing the low-temperature nano-Ag sintering technique and screening suitable Ti-Al alloys, a reliable interface with excellent connection performance has been realized. The Ti-Al intermetallic compounds effectively inhibit the diffusion process at Ti-34Al/Ge_0.9Sb_0.1Te interface. Thus, the thickness of the interfacial reaction layer only increases by ≈2.08 µm, and the interfacial electrical contact resistivity remains as low as ≈15.2 µΩ cm² even after 30 days of isothermal aging at 773 K. A high conversion efficiency of ≈11.3% has been achieved in the GeTe/PbTe module at a hot-side temperature of 773 K and a cold-side temperature of 300 K. More importantly, the module's performance and the reliability of the interface remain consistently stable throughout 50 thermal cycles and long-term aging. This work promotes the application of high-performance GeTe materials for thermoelectric power generation.