Tellurium-free thermoelectric materials and devices for low-temperature energy harvesting

Abstract

Harvesting low-temperature waste heat (below 573 K), which constitutes around 89% of the total waste heat, remains a considerable technical challenge. Thermoelectric (TE) power generation offers a viable solution to this issue. Currently, commercial TE technology relies almost exclusively on Bi2Te3, used predominantly for Peltier cooling. However, the scarcity of tellurium (Te), along with the lower TE performance and thermal stability of Bi2Te3 above 423 K, hampers its potential for energy harvesting. As a result, there has been a surge of interest in tellurium-free TE materials and devices, including MgAgSb, Mg3Sb2 and SnSe, as alternatives to Bi2Te3. In this Review, we highlight advancements and effective strategies for the development of Te-free thermoelectrics, from the material level to the interface and device levels. Specifically, we discuss the physical origin of their high-performance, computational strategies to design TE interface materials, as well as module assembly and design of practical power generation systems. We conclude by discussing the future prospects and challenges of these emerging systems for low-temperature energy harvesting. As alternatives to bismuth telluride, Te-free thermoelectric materials are emerging as promising candidates for low-temperature power generation. This Review discusses the design principles and future prospects of Te-free thermoelectric materials and devices across scales, from materials and interfaces to devices and system-level integration.