CALPHAD accelerated design of advanced full-Zintl thermoelectric device.

Yin, Li; Li, Xiaofang; Bao, Xin; Cheng, Jinxuan; Chen, Chen; Zhang, Zongwei; Liu, Xingjun; Cao, Feng et al. · Nat Commun · 2024

basic_science · Level V

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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<sub>2</sub>Ni has been identified as a matched contact layer for n-type Mg<sub>3</sub>Sb<sub>2</sub>-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<sub>3.15</sub>Co<sub>0.05</sub>SbBi<sub>0.99</sub>Se<sub>0.01</sub> 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<sub>0.9</sub>Mg<sub>0.9</sub>Zn<sub>1.198</sub>Ag<sub>0.002</sub>Sb<sub>2</sub>. Additionally, the thermal aging and thermal cycle experiments proved the long-term reliability of the Mg<sub>2</sub>Ni/Mg<sub>3.15</sub>Co<sub>0.05</sub>SbBi<sub>0.99</sub>Se<sub>0.01</sub> interface and the nano-silver sintering joints. Our work paves an effective avenue for the development of advanced devices for thermoelectric power generation.