Department of Chemistry and Biochemistry

Faculty: Cora Lind-Kovacs, Ph.D.

Office: WO 2262
Phone: (419) 530-1505
Fax: (419) 530-4033

Professional Background:
Prediploma, 1996, Bergische Universität Wuppertal, Germany
M.S. 1999, Ph.D., 2001, Georgia Institute of Technology
Postdoctoral Associate, 2001-2003, Cornell University


Research Synopsis:
Synthesis and characterization of new and improved solids; non-hydrolytic sol-gel chemistry; negative thermal expansion materials; polymer composites; battery expanders; powder x-ray methods; Rietveld method. 

The Lind-Kovacs group is pursuing research in the following target areas: 1) Synthesis and characterization of new negative thermal expansion (NTE) materials in the Sc2W3O12 family, 2) Incorporation of NTE materials into polymers, 3) Development of in situ methods for the preparation of inorganic/polymer composites and 4) Synthesis and characterization of model expander materials for advanced lead batteries.

Negative thermal expansion (NTE) materials

While most solids expand upon heating, a few classes of materials shrink with increasing temperature. This unusual property is based on the compounds' crystal structures. It has attracted growing attention during the last decade, as it can be used to counterbalance the normal, positive thermal expansion of other materials through the preparation of composites.

There are many factors that influence the usefulness of NTE materials for composites (temperature range over which NTE is observed, occurrence of temperature or pressure induced phase transitions, ease of preparation etc.). For each specific application, additional factors like magnitude of the expansion coefficient, compatibility with other composite components, and stability under the expected processing conditions, need to be considered. To date, no "ideal" NTE material has been prepared, limiting the choice of composite components to the "most suitable" NTE material instead.

Research in our group will focus on the preparation of new materials in the Sc2W3O12 family. This family shows the strongest dependence of expansion behavior on cation identity. The use of non-hydrolytic sol-gel chemistry allows the incorporation of a larger variety of cations than those accessible by traditional ceramic methods, and facilitates the preparation of highly homogenous mixed cation compounds. The expansion behavior of the resulting materials will be characterized by variable temperature powder x-ray diffraction in combination with Rietveld analysis.

Model Expander Molecules (MEMs) for advanced lead batteries

Lead batteries are well known for their use in vehicles, but have the potential to make significant additional contributions to an increasingly electric and decarbonized energy landscape. The battery electrodes contain a number of additives besides the actual lead species, which contribute to improved battery performance and lifetime. One of these additives consists of lignosulfonates (LS), which are also known as "expanders" as they help retain the porous nature of the lead electrode and thus the cyclability. LS have a strong effect on a battery's ability to discharge and charge at different rates, but the actual mechanism of interaction with the various lead species is unknown. Because LS are complex mixtures of large molecules with many functional groups, direct characterization of these interactions is not feasible. In collaboration with Argonne National Lab and 5 battery companies, our group is synthesizing MEMs that mimic various features of commercial expanders and characterize their interaction with lead species. Materials with promising effects will be tested in prototype batteries.

Notes for Crystallography Course

Last Updated: 7/15/24