Improved Thermoelectric Performance and Mechanical Properties of Nanostructured Melt-Spun β-Zn₄Sb₃

Abstract

β-Zn₄Sb₃ is one of the most important thermoelectric materials in the intermediate temperature range, but poor mechanical properties limit its commercial application. In this work we adopted a melt-spinning (MS) technique followed by a quick spark plasma sintering (SPS) procedure to fabricate nanostructured β-Zn₄Sb₃ bulk material with good thermoelectric performance and mechanical properties. The nanostructure had a significant influence on the thermoelectric transport properties and mechanical strength. Compared with the sample prepared by the traditional melting method (M-ingot), the Seebeck coefficient of the MS-SPS samples was significantly higher and the thermal conductivity was remarkably lower. In spite of the lower electrical conductivity, the σ/κ ratio increased in the high temperature range, leading to great improvement in the thermoelectric figure of merit (ZT). The maximum ZT value of 1.16 was obtained at 700 K for the MS-SPS-40 sample. Compared with the M-ingot sample, it was 47% higher at the same temperature. Moreover, the average compressive strength of the MS-SPS-40 sample reached 337.9 MPa, which is 130% higher than that of the M-ingot sample. β-Zn₄Sb₃ with such high mechanical strength has great potential for commercial application.