Reliable N-type Mg3.2Sb1.5Bi0.49Te0.01/304 stainless steel junction for thermoelectric applications

Abstract Mg3Sb2-based materials possess promising thermoelectric performances, however, probably poor interfacial behaviors when connected with the metal electrodes due to the strong chemical activity and volatility of the element Mg. In this paper, a high conversion efficiency of up to 9 % was achieved with a reliable Mg3.2Sb1.5Bi0.49Te0.01/304 stainless steel junction at a temperature difference of 370 K (Th = 673 K, Tc = 303 K). The transformation from a single ferritic structure (Fe) to an austenitic structure (304 stainless steel) insures the lower diffusion coefficient and higher expansion coefficient of 304 stainless steel, which contributes to the suppressed interfacial reaction, ideal electrical properties, and robust mechanical properties from room temperature to higher temperature.