Highly effective solid solution towards high thermoelectric and mechanical performance in Bi-Sb-Te alloys via Trojan doping

Shi, Yong-Cai1; Yang, Jianmin2; Wang, Yu1; Li, Zu-Gang1; Zhong, Tian-Yu1; Ge, Zhen-Hua1; Feng, Jing1; He, Jiaqing2

2024-03-19

10.1039/d4ee00132j

ENERGY & ENVIRONMENTAL SCIENCE   影响因子和分区

1754-5692

1754-5706

The optimization of electrical and thermal transport properties of thermoelectric materials greatly relies on achieving higher solubility of doping elements. In this study, we present a novel approach named Trojan doping, which utilizes NaBiS2 to increase the solubility of Na in p-type Bi0.42Sb1.58Te3 (BST) alloys. NaBiS2 is just like the Trojan horse, which brings Na ions into the BST matrix. The S elements were proved to play a role in keeping more Na dissolved in the BST matrix. This strategy reduces the total thermal conductivity of the BST alloy while enhancing its electrical transport properties due to the highly effective Na solid solution in the BST system. Among the BST + 4.0 wt% NaBiS2 samples, the highest peak ZT value of 1.44 was achieved at 373 K with a high ZT platform beyond 1.4, from 323 to 373 K. Furthermore, analysis of the defect formation energy obtained through density functional theory (DFT) calculations revealed that the coordination between Na and S exhibits a lower defect formation energy compared to that exhibited by Te coordination in the vicinity of Na. This reduction in the defect formation energy is attributed to the greater strength and stability of Na-S bonds compared to Na-Te bonds, as confirmed by crystal orbital Hamiltonian calculations. The solid solution of Na and S also resulted in a conversion efficiency of about 6.0% in single-leg devices, indicating their potential application in multi-leg devices. Moreover, the mechanical properties of the sample showed significant improvement. Specifically, the sample with a doping level of 4.0 wt% exhibited a 44.9% increase in hardness and a 41.3% increase in the modulus compared to the pure sample. This work demonstrates the feasibility of increasing the solid solubility of doping elements through Trojan doping, highlighting its potential application in other thermoelectric materials.

SCI ; EI

英语

通讯

National Key Research and Development Program of China[2022YFF0503804] ; National Key R&D Program of China[52162029] ; National Natural Science Foundation of China[202101AS070015] ; Yunnan Provincial Natural Science Key Fund[202201AV070005] ; Outstanding Youth Fund of Yunnan Province[202108]

Chemistry ; Energy & Fuels ; Engineering ; Environmental Sciences & Ecology

Chemistry, Multidisciplinary ; Energy & Fuels ; Engineering, Chemical ; Environmental Sciences

WOS:001177409600001

ROYAL SOC CHEMISTRY

Web of Science

1.Kunming Univ Sci & Technol, Fac Mat Sci & Engn, Kunming 650093, Peoples R China
2.Southern Univ Sci & Technol, Dept Phys, Shenzhen Key Lab Thermoelectr Mat, Shenzhen 518055, Peoples R China

Shi, Yong-Cai,Yang, Jianmin,Wang, Yu,et al. Highly effective solid solution towards high thermoelectric and mechanical performance in Bi-Sb-Te alloys via Trojan doping[J]. ENERGY & ENVIRONMENTAL SCIENCE,2024,17(6).

Shi, Yong-Cai.,Yang, Jianmin.,Wang, Yu.,Li, Zu-Gang.,Zhong, Tian-Yu.,...&He, Jiaqing.(2024).Highly effective solid solution towards high thermoelectric and mechanical performance in Bi-Sb-Te alloys via Trojan doping.ENERGY & ENVIRONMENTAL SCIENCE,17(6).

Shi, Yong-Cai,et al."Highly effective solid solution towards high thermoelectric and mechanical performance in Bi-Sb-Te alloys via Trojan doping".ENERGY & ENVIRONMENTAL SCIENCE 17.6(2024).