Improving the Mechanical Properties of Bi₂Te₃‐based Thermoelectric Materials by K₂Ti₆O₁₃ Whiskers

Abstract

Mechanically robust thermoelectric materials are essential for designing reliable thermoelectric modules. The Bi 2 Te 3 -based alloys show intrinsically poor mechanical properties, thus improving their mechanical performance is of great significance. In this work, the composites of p-type Bi 0.4 Sb 1.6 Te 3 and n-type Bi 2 Te 2.7 Se 0.3 (CuI) 0.003 with different K 2 Ti 6 O 13 whiskers contents are prepared. Due to the grain refinement and the whiskers strengthening mechanism of crack deflection, whiskers pulling out, and whiskers bridging, the mechanical properties of Bi 2 Te 3 -based materials are significantly improved. In addition, the zT value of the Bi 2 Te 3based alloys remains almost unchanged compared with the pristine sample. Our study indicates that whiskers strengthening is an effective route to enhance the mechanical properties of thermoelectric materials.