Simultaneous Optimization of Thermoelectric Transport and Mechanical Performance in Full‐Zintl CaCd 2 Sb 2 /Mg 3
Kejia Liu, Ruihuan Cheng, Yujie Huang, Xiaofang Li, Wenhua Xue, Haiqi Li, Huajian Wu, Yuxin Sun, Jinsuo Hu, Dongyi Shen, Xiaodong Wang, Chen Chen, Yue ChenABSTRACT
Achieving both high thermoelectric performance and robust mechanical strength remains a key pursuit for the practical deployment of thermoelectric applications. Herein, a solid‐solution approach is employed in CaCd 2 Sb 2 via alloying with EuMg 2 Sb 2 , achieving a synergistic optimization of electrical and phonon transport and mechanical performance. The incorporation of EuMg 2 Sb 2 facilitates band degeneracy, thereby substantially improving the electrical transport properties. Together with the reduced thermal conductivity, the optimized composition exhibits a peak zT of ∼ 1.4 at 750 K and an average zT of ∼ 0.81 between 300 and 750 K. Furthermore, solid‐solution strengthening markedly enhances the mechanical properties, thereby ensuring mechanical integrity for reliable device integration. Leveraging transient liquid phase bonding, a 2 × 2 full‐Zintl module combining this optimized p‐type material with Mg 3 Sb 2 ‐based n‐type legs achieves a conversion efficiency of ∼ 11% at a temperature difference of 422 K. This work highlights the viability of Zintl phases toward high‐efficiency thermoelectric modules.