SnSe + Ag2Se composite engineering with ball milling for enhanced thermoelectric performance
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Earth-abundant IV–VI semiconductor SnSe is regarded as a promising thermoelectric material due to its intrinsic low thermal conductivity. In this report, the highly textured SnSe/Ag2Se composites were first designed by solid solution method followed by spark plasma sintering (SPS) and their thermoelectric properties in two directions were investigated, and then, the performance of composites was further optimized with an additional ball milling. The coexistence of SnSe and Ag2Se phases is clearly confirmed by energy-dispersive X-ray spectroscopy (EDX) in transmission electron microscopy (TEM). After ball milling, the size of SnSe grains as well as the incorporated Ag2Se particles reduces effectively, which synergistically optimizes the electrical and thermal transport properties at high temperature range. As a result, a maximum ZT of ~ 0.74 at 773 K for SnSe + 1.0%Ag2Se in the direction vertical to the pressing direction is achieved. Composite engineering with additional ball milling is thus proved to be an efficient way to improve the thermoelectric properties of SnSe, and this strategy could be applicable to other thermoelectric systems.
KeywordsThermoelectrics SnSe Composite engineering Ball milling
This work was financially supported by the National Science Foundation (No. DMR-1410636), the Natural Science Foundation of Guangdong Province (No. 2015A030308001), the Leading Talents of Guangdong Province Program (No. 00201517), the Science, Technology and Innovation Commission of Shenzhen Municipality (Nos. JCYJ20150831142508365, KQTD2016022619565991 and KQCX2015033110182370) and the National Natural Science Foundation of China (No. 51632005). This work was also supported by Project funded by China Postdoctoral Science Foundation.
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