Achieving High Thermoelectric Performance of n-Type Bi 2 Te 2.79 Se 0.21 Sintered Materials by Hot-Stacked Deformation

• Published in: ACS applied materials & interfaces Vol. 13; no. 13; pp. 15429 - 15436
• Main Authors: Xiong, Chenglong, Shi, Fanfan, Wang, Hongxiang, Cai, Jianfeng, Zhao, Simao, Tan, Xiaojian, Hu, Haoyang, Liu, Guoqiang, Noudem, Jacques G, Jiang, Jun
• Format: Journal Article
• Language: English
• Published: United States 07-04-2021
• Subjects: phonon scattering; bismuth telluride; thermoelectric; n-type; hot-stacked deformation
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.1c02417

Bismuth telluride has been the only commercial thermoelectric candidate, but the n-type sintered material lags well behind the p-type one in the
value, which severely limits the further development of thermoelectrics. Here, we report a promising technique named hot-stacked deformation to effectively improve the thermoelectric properties of n-type Bi
Te
Se
+ 0.067 wt % BiCl
materials based on zone-melting ingots. It is found that a high grain alignment is maintained during the plastic deformation and the carrier concentration is properly optimized owing to the donor-like effect, leading to an enhanced power factor. Moreover, the lattice thermal conductivity is obviously suppressed due to the emerged phonon scattering centers of dense grain boundaries and dislocations. These effects synergistically yield a maximum
value of 1.38 and an average
of 1.18 between 300 and 500 K in the hot-stacked deformed sample, which is approximately 42% higher than those of the zone-melting ingots.