High temperature (>900°C) industrial waste heat recovery remains at the frontier in thermoelectric materials. The high temperature (greater than 1200°C), low heat-flux, and large surface area encountered in high temperature industrial reactors imply that materials cost dictates deployment. Molten semiconductors are one cost-effective material option that remains understudied. Here we report the performance of a laboratory-scale device based on molten SnS, in particular the Figure of Merit (ZT) and the conversion efficiency of this first generation of material. Furthermore, a discussion of the Seebeck and transport properties of molten SnS is proposed [1]. It is found that electronic properties of molten semiconductors are promising, and that the remaining question lies in the thermal transport properties. Recent experimental results show that thermal transport in molten SnS involves drastically different mechanisms than in the solid-state , and it calls for advances in the prediction and evaluation of physical properties of molten materials. The results with SnS highlight the materials and engineering challenges that will allow the next generation of molten semiconductors to be developed.

[1] Youyang Zhao, Charles Rinzler, and Antoine Allanore, Molten Semiconductors for High Temperature Thermoelectricity, ECS J. Solid State Sci. Technol. 2017 6(3): N3010-N3016; doi:10.1149/2.0031703jss