title: Nano- and Microstructure Engineering: An Effective Method for Creating High Efficiency Magnesium Silicide Based Thermoelectrics.
abstract: Considering the effect of CO2emission together with the depletion of fossil fuel resources on future generations, industries in particular the transportation sector are in deep need of a viable solution to follow the environmental regulation to limit the CO2emission. Thermoelectrics may be a practical choice for recovering the waste heat, provided their conversion energy can be improved. Here, the high temperature thermoelectric properties of high purity Bi doped Mg2(Si,Sn) are presented. The samples Mg2Si1-x-ySnxBiywith x(Sn) ≥ 0.6 and y(Bi) ≥ 0.03 exhibited electrical conductivities and Seebeck coefficients of approximately 1000 Ω-1cm-1and -200 μV K-1at 773 K, respectively, attributable to a combination of band convergence and microstructure engineering through ball mill processing. In addition to the high electrical conductivity and Seebeck coefficient, the thermal conductivity of the solid solutions reached values below 2.5 W m-1K-1due to highly efficient phonon scattering from mass fluctuation and grain boundary effects. These properties combined for zT values of 1.4 at 773 K with an average zT of 0.9 between 400 and 773 K. The transport properties were both highly reproducible across several measurement systems and were stable with thermal cycling.
authors.affiliation: Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo , Waterloo, ON N2L 3G1, Canada.
authors.forename: Nader
authors.initials: N
authors.lastname: Farahi
authors.affiliation: Materials Science and Engineering Department, McMaster University , Hamilton, ON L8S 4L8, Canada.
authors.forename: Sagar
authors.initials: S
authors.lastname: Prabhudev
authors.affiliation: Materials Science and Engineering Department, McMaster University , Hamilton, ON L8S 4L8, Canada.
authors.forename: Gianluigi A
authors.initials: GA
authors.lastname: Botton
authors.affiliation: General Motors Research & Development Center , Warren, Michigan 48154, United States.
authors.forename: James R
authors.initials: JR
authors.lastname: Salvador
authors.affiliation: Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo , Waterloo, ON N2L 3G1, Canada.
authors.forename: Holger
authors.identifier: http://orcid.org/0000-0002-6777-6140
authors.initials: H
authors.lastname: Kleinke
keywords: high efficiency; magnesium silicide; microstructure; nanostructure; thermoelectric