Robust Bi2(Te,Se)3 Thermoelectrics From Large Shrinkage Ratio Extrusion Drives Advanced Peltier Microcooler and Power Generator

Abstract

The “Barrel Effect” of n-type Bi₂Te₃ materials have always been the biggest obstacle to expanding thermoelectric commercial applications. This work develops an industrial-scale large shrinkage ratio extrusion method that synchronously coordinates appropriate texturing and modifies atomic defects, as well as micro and nanostructures, prompting simultaneous gains in rods with a diameter of 30 mm increases to ≈1.20 at 325 kelvin, with flexural and compressive strengths significantly improve to 77.7 and 192.4 MPa, respectively. Successfully fabricated Peltier microcoolers (1 × 3 mm² cross-section) exhibit a competitive maximum cooling temperature difference of 90.6 kelvin at a hot-side temperature of 348 kelvin. A designed and integrated 17-by-17 power generator demonstrates a high conversion efficiency of 7% under a 200-kelvin temperature gradient and highlights operational stability. These achievements hold great potential for advancing applications in compact solid-state cooling and low-grade waste heat recovery.