Thermoelectric devices directly convert heat into electricity and can provide additional power for automotive functions. Earth abundant, light-weight elements, and materials with a high stability above the working temperature range of the exhaust manifold of automobile engines are the materials requirements for this idea to become reality. Mg2Si is an n-type semiconductor and the electrical resistivity can be tuned by changing the carrier concentration with dopants making it an important material for this application. Thermal conductivity can be reduced by scattering of mid- and long-wavelength phonons by the presence of nanoparticles in the matrix. The power factor may also increase by selective scattering of hot carriers by controlling the heterostructure band offset and the potential barrier of nanoparticles with respect to the matrix. The samples were characterized by powder X-ray diffraction, thermogravimetric/differential scanning calorimetry (TG/DSC), and scanning transmission electron microscopy (STEM). Thermopower, electrical resistivity, and thermal conductivity data and scanning electron microscopy (SEM) and electron microprobe analysis (EMPA) on spark plasma sintered pellets will be presented. I will discuss how the optimization of the electronic states of the matrix and nanoparticle size and composition can further enhance the figure of merit.

Nanocomposites of Mg<sub>2</sub>Si for high performance thermoelectric applications

245th National Meeting (2013)

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Nanocomposites of Mg2Si for high performance thermoelectric applications

Nanocomposites of Mg₂Si for high performance thermoelectric applications