High‐Efficiency Thermoelectric Module Based on High‐Performance Bi0.42Sb1.58Te3 Materials

• Published in: Advanced functional materials Vol. 33; no. 47
• Main Authors: Wu, Gang, Zhang, Qiang, Fu, Yuntian, Tan, Xiaojian, Noudem, Jacques G., Zhang, Zongwei, Cui, Chen, Sun, Peng, Hu, Haoyang, Wu, Jiehua, Liu, Guo‐Qiang, Jiang, Jun
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 16-11-2023
• Subjects: Bi0.42Sb1.58Te3; Bismuth; Carrier density; conversion efficiency; Crystal defects; devices; Grain boundaries; Heat conductivity; heat harvest; Heat transfer; Materials science; Modules; Point defects; Room temperature; Synergistic effect; Tellurides; Thermal conductivity; Thermoelectricity; thermoelectrics
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202305686

Bismuth‐telluride‐based alloy is the sole thermoelectric candidate for commercial thermoelectric application in low‐grade waste heat harvest near room temperature, but the sharp drop of thermoelectric properties at higher temperature and weak mechanical strength in zone‐melted material are the main obstacles to its wide development for power generation. Herein, an effective approach is reported to improve the thermoelectric performance of p‐type Bi0.42Sb1.58Te3 hot‐pressed sample by incorporating Ag5SbSe4. A peak ZT of 1.40 at 375 K and a high average ZT of 1.25 between 300 and 500 K are achieved. Such outstanding thermoelectric performance originates from the synergistic effects of improved density‐of‐states effective mass, reduced bipolar thermal conductivity by the boosted carrier concentration, and suppressed lattice thermal conductivity by the induced phonon scattering centers including substitute point defects, dislocations, stress–strain clusters, and grain boundaries. Comprised of the p‐type Bi0.42Sb1.58Te3 + 0.10 wt% Ag5SbSe4 and zone‐melted n‐type Bi2Te2.7Se0.3, the thermoelectric module exhibits a high conversion efficiency of 6.5% at a temperature gradient of 200 K, indicating promising applications for low‐grade heat harvest near room temperature.
Ag5SbSe4 doping not only enhances the average power factor of Bi0.42Sb1.58Te3 by improved density‐of‐states effective mass, but also reduces the lattice thermal conductivity by induced multiscale defects. Consequently, a peak ZT of 1.40 at 375 K and a conversion efficiency of 6.5% is achieved at ΔT = 200 K, which is better than most of previously reported results.