Speaker: Alamgir Karim, William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston
Abstract: We will provide a brief introduction to the Chemical and Biomolecular Engineering Program at University of Houston, with overview of the research themes of various faculty members in the Department. This will be followed by a focused talk on research i
n my group on recent advancements in both fundamental knowledge and applied strategies towards development of polymers and 2D nanomaterials for advanced and flexible energy storage devices of the future.
The need for high power density, flexible, pulsed power and lightweight energy storage devices requires the use of polymer film-based dielectric capacitors. Elevating their use for advancd energy applications such as EVs however requires significant enhancement of their energy densities. The maximum energy storage density of a dielectric capacitor is directly proportional to the square of the maximum voltage that can be applied to the dielectric without causing the breakdown. Theoretically, it has been shown that chain ends contribute adversely to the electrical breakdown of polymer dielectrics at high electric fields, resulting in low energy density in polymer capacitors. In this work, we enhanced the dielectric breakdown voltage and hence the energy density of the polymer capacitor by using a variety of strategies: a) by utilizing well-ordered high molecular weight block copolymers (BCP), in which the chain ends are segregated to narrow zones, b) study energy storage in films of cyclic homopolymers that have no no chain ends, c) study effect of ultra-confinement in high molecular weight homopolymers, and d) investigate thin film heterostructure capacitor based on poly(vinylidene fluoride)/poly(methyl methacrylate)/poly(vinylidene fluoride) with stratified 2D nanofillers (Mica or h-BN nanosheets) (PVDF/PMMA-2D fillers/PVDF), that shows enhanced permittivity, high dielectric strength and an ultra-high energy density of ≈ 75 J/cm3 with efficiency over 79%. Density functional theory calculations verify the observed permittivity enhancement. These approaches of using polymer and polymer based heterostructure composites is expected to be universal for designing high energy density thin film polymeric dielectric capacitors for myriads of applications.
Bio: Alamgir Karim is the Dow Chair Professor in the William A. Brookshire Department of Chemical and Biomolecular Engineering, and Director of Materials Science and Engineering Program at the University of Houston. He obtained his Ph.D. in Physics from Northwestern University in Illinois, and did a post-doc in Chemical Engineering at
University of Minnesota. He previously held positions of Group Leader of Polymer Blends, Combinatorial Methods and Nanomaterials Group at the National Institute of Standards and Technology (NIST), in Gaithersburg, Maryland. At University of Akron, he was Goodyear Chair Professor in Polymer Engineering, and Director, Akron Functional Materials Center and Associate Dean of Research and Institute Director. His current areas of research include polymers for energy and sustainability. He has published over 250 papers with an h-index of 67 and edited several books in these areas of polymer research, and organized several international conferences. He is a Fellow of the American Physical Society (APS), Fellow of American Association for the Advancement of Science (AAAS), Fellow of Neutron Scattering Society of America (NSSA) and recipient of Keck and Welch Foundation Awards.