CALPHAD accelerated design of advanced full-Zintl thermoelectric device.

Since thermoelectric materials have different physical and chemical properties, the design of contact layers requires dedicated efforts, and the welding temperatures are distinctly different. Therefore, a general interface design and connection technology can greatly facilitate the development of thermoelectric devices. Herein, we proposed a screening strategy for the contact materials based on the calculation of phase diagram method, and Mg 2 Ni has been identified as a matched contact layer for n-type Mg 3 Sb 2 -based materials. And this screening strategy can be effectively applied to other thermoelectric materials. By adopting the low-temperature sintering silver nanoparticles technology, the Zintl phase thermoelectric device can be fabricated at low temperature but operate at medium temperature. The single-leg n-type Mg 3.15 Co 0.05 SbBi 0.99 Se 0.01 device achieves an efficiency of ~13.3%, and a high efficiency of ~11% at the temperature difference of 430 K has been realized for the Zintl phase thermoelectric device comprised together with p-type Yb 0.9 Mg 0.9 Zn 1.198 Ag 0.002 Sb 2 . Additionally, the thermal aging and thermal cycle experiments proved the long-term reliability of the Mg 2 Ni/Mg 3.15 Co 0.05 SbBi 0.99 Se 0.01 interface and the nano-silver sintering joints. Our work paves an effective avenue for the development of advanced devices for thermoelectric power generation.