Large-scale SHS based 3D printing of high-performance n-type BiTeSe: Comprehensive development from materials to modules. (May 2022) - Zhan, Ruoyu
Abstract: Micro thermoelectric devices have a broad application prospect in confined space refrigeration and power generation of small nodes in the Internet of things. The leg performance, manufacturing efficiency and yield are very important for the industrial production of thermoelectric devices. Here, self-propagating high-temperature synthesis (SHS) and selective laser melting (SLM) technique are combined to directly form a dense and highly growth-oriented n-type BiTeSe material in large scale from raw materials of Bi, Te and Se powders. Ignoring the solid solution of a small amount of Se, the composition and structure analysis of the micro-region via transmission electron microscopy shows that Bi first reacts with Te to form BiTe compound in the molten pool of laser, and then Te reacts with the intermediate BiTe to form Bi2 Te3 phase. In the next manufacturing process, a thin bulk material with a size of 60 × 30 × 0.5 mm 3 can be printed out within 1 h. Because of the excellent mechanical properties, 4000 valid legs with a size of 0.4 mm × 0.4 mm in plane can be obtained successfully. Finally, a micro thermoelectric device is fabricated via using 3D-printed n-type BiTeSe and commercially hot extrusion p-type BiSbTe legs (28 pairs). For solid refrigeration, the maximum cooling temperature difference is about 44 °C and the maximum cooling power Q max of the device is about 2.1 W when the input current I max is about 1.1 A. For power generation, the open-circuit voltage U oc is 324 mV and the maximum output power P max is 4.97 mW when Δ T is 40 K. Graphical abstract: Image 1 Highlights: The SLM-based SHS reaction mechanism is clarified via transmission electron microscopy. The 3D printed bulk material shows preferential orientation of (hk0) perpendicular to the building direction (BD). A thin bulk material with a size of 60 × 30 × 0.5 mm 3 can be printed out within 1 h. A micro TE device is fabricated via using 3D-printed BiTeSe and commercially hot extrusion BiSbTe legs (28 pairs). Abstract : Large scale SHS-based 3D printing BiTeSe bulk material can be prepared efficiently and has high yield at the same time.