Enhanced Thermoelectric Performance by Strong Phonon Scattering at the Heterogeneous Interfaces of the Mg<sub>2</sub>Sn/Mg<sub>3</sub>Sb<sub>2</sub> High-Content Nanocomposite
Yongbin Zhu, Zhijia Han, Bing Han, Feng Jiang, Xinzhi Wu, Cheng‐Gong Han, Yonghong Deng, Weishu Liu
Abstract
Nano approaches are practical strategies to boost the thermoelectric figure of merit due to the strong phonon scattering from the grain boundaries and nanoinclusions. Here, we have reported a strong phonon scattering at the heterogeneous interfaces of Mg2Sn/Mg3Sb2 high-content nanocomposites (HCnCs). As a result, a significantly reduced lattice thermal conductivity of 1.09 W m–1 K–1 was observed in the equimolar Mg2Sn/Mg3Sb2 HCnC, 80% lower than pure Mg2Sn and 25% lower than pure Mg3Sb2. As a result, a high ZT ∼ 1.13 at 773 K was achieved in the Mg2Sn/Mg3Sb2 HCnC. Furthermore, various defects, including solid solutions, nanoinclusions, and misfit dislocations, were observed in both the Mg3Sb2 phase and the Mg2Sn phase through the microstructure characterization.