Towards tellurium-free thermoelectric modules for power generation from low-grade heat.

Ying, Pingjun; He, Ran; Mao, Jun; Zhang, Qihao; Reith, Heiko; Sui, Jiehe; Ren, Zhifeng; Nielsch, Kornelius et al. · Nat Commun · 2021

basic_science · Level V

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Abstract

Thermoelectric technology converts heat into electricity directly and is a promising source of clean electricity. Commercial thermoelectric modules have relied on Bi<sub>2</sub>Te<sub>3</sub>-based compounds because of their unparalleled thermoelectric properties at temperatures associated with low-grade heat (<550 K). However, the scarcity of elemental Te greatly limits the applicability of such modules. Here we report the performance of thermoelectric modules assembled from Bi<sub>2</sub>Te<sub>3</sub>-substitute compounds, including p-type MgAgSb and n-type Mg<sub>3</sub>(Sb,Bi)<sub>2</sub>, by using a simple, versatile, and thus scalable processing routine. For a temperature difference of ~250 K, whereas a single-stage module displayed a conversion efficiency of ~6.5%, a module using segmented n-type legs displayed a record efficiency of ~7.0% that is comparable to the state-of-the-art Bi<sub>2</sub>Te<sub>3</sub>-based thermoelectric modules. Our work demonstrates the feasibility and scalability of high-performance thermoelectric modules based on sustainable elements for recovering low-grade heat.