Homo‐Crystalline Interfaces for Durable Thermoelectric Generation

Enhancing average dimensionless figure of merit ( ZT ) through segmentation is central to thermoelectric energy conversion, yet practical application is hindered by the kinetic and electrical instability of conventional soldered hetero‐interfaces. Herein, we introduce a seamless partitioning (SP) approach that creates compositionally graded, homo‐crystalline interfaces within Bi‐Sb‐Te through a one‐step sintering process, eliminating foreign interlayers. The yielded coherent and semi‐coherent interfaces with minimal misfit strongly suppress interdiffusion and defect mobility, establishing an intrinsically stable interfacial configuration with a thermally robust contact resistivity and bulk‐like mechanical integrity, based on which SP‐based modules achieve a conversion efficiency up to 7.6% at a temperature difference of 250 K, outperforming state‐of‐the‐art Bi 2 Te 3 ‐ and Mg 3 (Bi,Sb) 2 ‐based modules and retaining stable performance after 100 h of thermal endurance. This interface‐intrinsic design links atomic configuration, kinetic stability, and module‐level reliability, offering a general blueprint for high‐performance thermoelectric.