MRSEC: Structure and Property Relationships in Thermoelectric Materials and Solid Electrolytes
Physical and transport properties in solids arise from, and are strongly influenced by, the structure of a material. The understanding of crystal structures and their correlation to the observed transport phenomena play a crucial role in finding and optimizing new materials for specific applications. Li-ion conducting solid electrolytes and thermoelectric materials will be discussed as examples to illustrate the structure-property relationships. Firstly, isoelectronic substitution in the garnet type Li6MLa2Ta2O12 and its influence on the Li+ transport in this class of solid electrolytes will be presented. A combination of synchrotron and neutron diffraction, neutron total scattering and AC impedance spectroscopy will show our understanding of the structural influence on the lithium ion conductivities in this class of materials. Secondly, thermal transport in Zintl phases and quaternary copper selenide thermoelectrics will be discussed with a focus on understanding thermal transport and the role of phonon scattering mechanisms. Specifically, the substitution-induced charge imbalance, which triggers phase segregation in quaternary copper selenides, influences the thermal transport properties. Likewise, phonon scattering through anisotropic structural disorder in these materials demonstrates different chemical and structural strategies for improved thermoelectric properties.
Bio: Wolfgang Zeier was born in Germany (1985) and studied Chemistry at the Johannes Gutenberg-University in Mainz. After a research stay with Prof. Hans-Conrad zur Loye (University of South Carolina) in 2008 focusing on crystal growth of oxides, he received his Diploma in Chemistry (M.Sc.) in 2010. His Diploma research with Dr. G. Jeffrey Snyder (California Institute of Technology) focused on the thermoelectric transport of the Zintl phase Ca3AlSb3. Dr. Zeier conducted his graduate studies in the field of thermoelectrics as a joint student of Dr. Snyder and Prof. Wolfgang Tremel at the Johannes Gutenberg-University in Mainz, where he received his Ph.D. in 2013. After his dissertation, he became a postdoctoral fellow at the University of Southern California with Prof. Brent Melot changing his research field from thermoelectrics to Li+ conducting solid electrolytes. Currently, Dr. Zeier is researching the influence of ion-conduction on thermoelectric transport at the California Institute of Technology.