CALPHAD accelerated design of advanced full-Zintl thermoelectric device

Abstract

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 Mg₂Ni has been identified as a matched contact layer for n-type Mg₃Sb₂-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_3.15Co_0.05SbBi_0.99Se_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_0.9Mg_0.9Zn_1.198Ag_0.002Sb₂. Additionally, the thermal aging and thermal cycle experiments proved the long-term reliability of the Mg₂Ni/Mg_3.15Co_0.05SbBi_0.99Se_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.