|Title: Thermoelectric energy generation: improving efficiency through crystal chemistry|
Abstract: Thermoelectric devices, which directly convert thermal energy to electrical energy, have the potential to play a significant role in our global energy infrastructure. While thermoelectric generators are currently indispensible in space exploration and other specialized applications, further improvements in efficiency are required for them to be widely used in automotive and industrial waste heat recovery. High efficiency thermoelectric materials must strike a balance between high electrical conductivity (found in metals), low thermal conductivity (found in glasses or polymers), and high Seebeck coefficients (found in insulators). Understanding the influence of the crystal structure, composition, and chemistry of thermoelectric materials on their thermal and electronic transport properties is critical to engineering materials with improved conversion efficiency. In this talk, I will introduce a class of thermoelectrics known as Zintl compounds, which crystallize in an astounding variety of complex structural arrangements. Our exploration of structurally complex Zintl antimonides as novel thermoelectric materials has demonstrated that such compounds meet all of the fundamental requirements for high efficiency: glass-like lattice thermal conductivity, a band gap in the electronic structure, and tunable electronic properties. This work provides a unique window into the relationship between crystal structure and transport properties in complex semiconductors, and has led to the discovery of several new promising thermoelectric materials for high temperature energy generation.
Bio: Alexandra Zevalkink is an assistant professor in the Department of Chemical Engineering and Materials Science at Michigan State University. She received her B.S. from Michigan Technological University in 2008 and her Ph.D. at the California Institute of Technology in 2014. After completing her Ph.D., she pursued postdoctoral research at NASA's Jet Propulsion Laboratory and at the Max Planck Institute for Chemical Physics of Solids in Dresden, Germany. Her research focus is on the relationship between the atomic structure and bonding in inorganic materials and the resulting thermal, electronic, and mechanical properties.