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

Mechanically robust thermoelectric materials are essential for designing reliable thermoelectric modules. The Bi₂Te₃-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_0.4Sb_1.6Te₃ and n-type Bi₂Te_2.7Se_0.3(CuI)_0.003 with different K₂Ti₆O₁₃ 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 Bi₂Te₃-based materials are significantly improved. In addition, the zT value of the Bi₂Te₃-based 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.