Ultrahigh thermoelectricity obtained in classical BiSbTe alloy processed under super-gravity
Min Zhou, Haojian Su, Jun Pei, Li Wang, Hua‐Lu Zhuang, Jing‐Feng Li, Kun Song, Haoyang Hu, Jun Jiang, Qinghua Zhang, Jiangtao Li, Laifeng Li, Jiangtao Li, Laifeng Li
Abstract
Abstract Thermoelectric materials allow direct conversion between heat and electricity and may be useful for power generation or solid-state refrigeration. However, improving thermoelectric performance is challenging because of the strong coupling between the electrical and thermal transport properties. We demonstrate a new super-gravity-field re-melting fabrication technology that synergistically optimizes the thermoelectric performance. Using a super-gravity field, the brittle (Bi,Sb) 2 Te 3 alloy undergoes unusual plastic deformation and forms mounts of microstructure defects, which is rarely observed in common fabrication process. As a result, the microstructure reconstruction and carrier concentration optimization were simultaneously realized, resulting in an ultra-low lattice thermal conductivity of <0.25 W/m K and a record-high figure of merit of >1.91 in the BiSbTe alloy. The strong enhancement of thermoelectric properties was validated in a thermoelectric module with high conversion efficiency of 6.4% and corresponding output power density of 0.34 W/cm 2 when subjected to a temperature difference of 185 K. This work highlights a new super-gravity strategy to achieve a high thermoelectric performance, which may be applicable to other thermoelectric materials.