Journal of Inorganic Materials, Volume. 36, Issue 8, 835(2020)
Mg3Sb2 compound has attracted much attention due to the promising thermoelectric properties and cost advantage. However, it is quite difficult to control Mg content during synthesizing processes because of high saturation vapor pressure and chemical reactivity of Mg element. Herein, Mg3(1+z)Sb2 (z=0, 0.02, 0.04, 0.06 and 0.08) samples were prepared by combination of solid state reaction, ball milling and spark plasma sintering (SPS). Their effects of Mg content on thermoelectric properties of Mg3Sb2 compounds were investigated in this study. Results indicate that actual Mg content rises with nominal Mg content increasing, and their point defect type changes from Mg vacancy(${{\text{{V}''}}_{\text{Mg}}}$) to interstitial Mg($\text{Mg}_{\text{i}}^{\centerdot \centerdot }$), leading to transition of transport behavior from p type (hole carriers predominated) for Mg3(1+z)Sb2 (z=0, 0.02, 0.04) samples to n type (electron carriers predominated) for Mg3(1+z)Sb2 (z=0.06, 0.08) samples. Besides, Mg3(1+0.04)Sb2 sample shows the highest ZT value from room temperature to 770 K, and achieves maximum ZT of 0.28 at 800 K. Additionally, Mg3(1+0.04)Sb2 sample exhibits intrinsic p-type transport behavior for Mg3Sb2 compound, which could serve as matrix to be extrinsically doped in the future study for further improvements of electrical properties and ZT value.
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Xu LU, Jichong HOU, Qiang ZHANG, Jianfeng FAN, Shaoping CHEN, Xiaomin WANG.
Category: RESEARCH ARTICLE
Received: Sep. 15, 2020
Accepted: --
Published Online: Dec. 8, 2021
The Author Email: ZHANG Qiang (zhangqiang@tyut.edu.cn), WANG Xiaomin (wangxiaomin@tyut.edu.cn)