High figure of merit and thermoelectric properties of Bi-doped Mg{sub 2}Si{sub 0.4}Sn{sub 0.6} solid solutions

Journal Article · Mon Jul 15 04:00:00 UTC 2013 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.04.041· OSTI ID:22309055

Liu, Wei ^[1]; Zhang, Qiang; Yin, Kang ^[1]; Chi, Hang; Zhou, Xiaoyuan ^[2]; Tang, Xinfeng ^[1]; Uher, Ctirad ^[2]

---

1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)
2. Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States)

The study of Mg{sub 2}Si{sub 1−x}Sn{sub x}-based thermoelectric materials has received widespread attention due to a potentially high thermoelectric performance, abundant raw materials, relatively low cost of modules, and non-toxic character of compounds. In this research, Mg{sub 2.16}(Si{sub 0.4}Sn{sub 0.6}){sub 1−y}Bi{sub y} solid solutions with the nominal Bi content of 0≤y≤0.03 are prepared using a two-step solid state reaction followed by spark plasma sintering consolidation. Within this range of Bi concentrations, no evidence of second phase segregation was found. Bi is confirmed to occupy the Si/Sn sites in the crystal lattice and behaves as an efficient n-type dopant in Mg{sub 2}Si{sub 0.4}Sn{sub 0.6}. Similar to the effect of Sb, Bi doping greatly increases the electron density and the power factor, and reduces the lattice thermal conductivity of Mg{sub 2.16}Si{sub 0.4}Sn{sub 0.6} solid solutions. Overall, the thermoelectric figure of merit of Bi-doped Mg{sub 2.16}Si{sub 0.4}Sn{sub 0.6} solid solutions is improved by about 10% in comparison to values obtained with Sb-doped materials of comparable dopant content. This improvement comes chiefly from a marginally higher Seebeck coefficient of Bi-doped solid solutions. The highest ZT∼1.4 is achieved for the y=0.03 composition at 800 K. - Graphical abstract: (a)The relationship between electrical conductivity and power factor for Sb/Bi-doped Mg{sub 2.16}(Si{sub 0.4}Sn{sub 0.6}){sub 1−y}(Sb/Bi){sub y} (0

• OSTI ID: 22309055
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 203; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CRYSTAL LATTICES
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRON DENSITY
MAGNESIUM SILICIDES
POINT DEFECTS
RAW MATERIALS
SCATTERING
SOLID SOLUTIONS
SOLIDS
TEMPERATURE DEPENDENCE
THERMAL CONDUCTIVITY
THERMOELECTRIC MATERIALS
THERMOELECTRIC PROPERTIES
TOXICITY