Effect of Excessive Antimony on the Thermoelectric and Transport Properties of Mg 3 Sb 2 Synthesized by Controlled Melti
- PDF / 1,826,170 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 72 Downloads / 256 Views
ORIGINAL ARTICLE - ENERGY AND SUSTAINABILITY
Effect of Excessive Antimony on the Thermoelectric and Transport Properties of Mg3Sb2 Synthesized by Controlled Melting, Pulverizing Followed by Vacuum Hot Pressing Md. Mahmudur Rahman1 · A. K. M. Ashiquzzaman Shawon1 · Soon‑Chul Ur1 Received: 10 June 2020 / Accepted: 23 September 2020 © The Korean Institute of Metals and Materials 2020
Abstract Zintl compounds were recognized as very good thermoelectric candidate due to their characteristics electron-crystal phononglass properties. Mg3Sb2 is a known Group II–V Zintl semiconductor. This compound is a well-established thermoelectric material and many of recent works focus on this compound due to its intrinsic low thermal conductivity. The band gap of this compound has been shown to be optimum, making it a promising thermoelectric material. This work introduces a new synthetic method and analyzes the thermoelectric properties found using this method. The single phase of M g3Sb2 was synthesized by melting elemental shots at 1173 K for 1 hour in a controlled inert Ar gas atmosphere in a tapped graphite crucible followed by vacuum hot pressing at 873 K for 4 hours. X-ray diffraction and scanning electron microscopy were carried out to investigate existing phases and surface morphology respectively. Thermoelectric properties in terms of Seebeck coefficient, electrical conductivity, and thermal conductivity were evaluated and the results are discussed in comparison to analogous studies. Transport properties were also evaluated and discussed. Single phase magnesium antimonide was found with a nominal formula of Mg3.8 Sb2 and showed a comparable ZT value which is ~ 0.24 at 873 K. Graphic Abstract
Keywords Mge3Sb2 · Controlled melting · Vacuum hot pressing · Zintl phase · Thermoelectric * Soon‑Chul Ur [email protected] 1
Department of Material Science and Engineering, Research Center for Sustainable Eco‑Devices and Materials (ReSEM), Korea National University of Transportation, Chungju, Chungbuk, Republic of Korea
13
Vol.:(0123456789)
Electronic Materials Letters
1 Introduction Thermoelectric devices have the ability to convert electricity into thermal energy directly and vice versa, which can reduce greenhouse gas (like CO2) emissions to provide cleaner forms of energy [1]. The big challenge with these materials is to get high conversion efficiency. The performance of thermoelectric materials is determined by the dimensionless figure of merit ZT and calculated by the following equation
eZT =
S2 σ T κ
(1)
Here, S is the Seebeck coefficient, σ is the electrical conductivity, κ is the thermal conductivity and T is temperature. As shown in Eq. (1), ZT value is directly proportional to the Seebeck coefficient and inversely proportional to the thermal conductivity. However, the electrical conductivity is also proportional to the thermal conductivity according to Widemann–Franz law (κE = σL0T, where κE = electronic thermal conductivity and L 0 = Lorenz number) [2]. On the other hand, as the carrier concentration
Data Loading...
