High-Efficiency and Stable Thermoelectric Module Based on Liquid-Like Materials

Thermoelectric technology provides an alternative way to use fossil energy more efficiently through converting the waste heat into electricity. In the past two decades, various kinds of novel thermoelectric materials have been reported with ultra-high figures of merit (zT). However, some of them, such as liquid-like materials Cu_2-δX (X = S, Se, and Te) and Zn₄Sb₃, possess low thermodynamic stability and thus lead to possible module instability during service. Here we provide a rational design strategy for achieving stable and highly efficient thermoelectric modules based on liquid-like materials. According to this strategy, a prototype Cu₂Se/Yb_0.3Co₄Sb₁₂ module is successfully built with good stability and high efficiency up to 9.1%, more than 50% higher than those made by half-Heusler and SiGe alloys. This work accelerates the development of liquid-like thermoelectric materials for high-efficiency modules in real applications. Recently, many novel thermoelectric materials have been reported with ultra-high performance. However, some of them (e.g., Cu/Ag-based liquid-like materials) possess low thermodynamic stability. Here, we successfully achieve both good stability and high efficiency in a thermoelectric module based on high-performance liquid-like materials through tuning the geometry of the legs to ensure the voltage applied on the liquid-like materials is below their threshold for stable usage. This work accelerates the development of liquid-like thermoelectric materials for high-efficiency modules in real applications.