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

Pingjun Ying,Kornelius Nielsch,Zhifeng Ren,Jun Mao,Heiko Reith,Jiehe Sui,Ran He,Gabi Schierning,Qihao Zhang

doi:10.1038/s41467-021-21391-1

Abstract

Thermoelectric technology converts heat into electricity directly and is a promising source of clean electricity. Commercial thermoelectric modules have relied on Bi2Te3-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 Bi2Te3-substitute compounds, including p-type MgAgSb and n-type Mg3(Sb,Bi)2, 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 Bi2Te3-based thermoelectric modules. Our work demonstrates the feasibility and scalability of high-performance thermoelectric modules based on sustainable elements for recovering low-grade heat.

Highlights

Thermoelectric technology converts heat into electricity directly and is a promising source of clean electricity
High-performance TE materials with simple synthesis are favored for module fabrication
With a hot-side temperature (Thot) of 548 K and a cold-side temperature (Tcold) of 293 K, we evaluated the maximum conversion efficiency as a function of the working current (I), the ratio of the cross-sectional areas between the p- and n-type legs (Ap/An), and the height ratio of the two n-type materials (HnSb0.7/Hn-Sb0.5) in a segmented leg (Fig. 3a and Supplementary Fig. 2)

Summary

Introduction

Thermoelectric technology converts heat into electricity directly and is a promising source of clean electricity. Our work demonstrates the feasibility and scalability of high-performance thermoelectric modules based on sustainable elements for recovering low-grade heat. Effective harnessing this “cooler” heat to generate electricity is vital for alleviating the burden on the energy supply and reducing the emission of greenhouse gases Potential technologies, such as the organic Rankine cycle[3,4], thermogalvanic cells[5], and thermo-osmotics[6] are being explored, these are limited by their low efficiencies, short lifetimes, and difficulty in system integration. For successful delivery, it is essential to employ synthesis routines that are potentially scalable for these Te-free TE modules, as well as to address their device-level issues such as geometry optimization, brazing process, and contact optimization, etc.[23] Till despite their promise, the assembly of these substitute compounds into powergeneration modules has not been reported

Methods

Results

Conclusion