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 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.