Marie Calendar's Restaurant ,
790 West Winton Avenue, CA 94545
(Click for map)
6:20 pm. to 7:00 pm. Cost: $18 for members; $12 for students. Dinner includes salad, cornbread, mashed potatoes, vegetables, meatloaf, lemon chichen and soda. (No cost to attend the presentation only)
Zach Liu, via email (firstname.lastname@example.org) or phone (510-239-2742) by Friday, April 14, 2006. Please indicate if you will attend both the talk and dinner or only the talk.
Membership in ECS is not a requirement for attendance.
Sarah Stewart is a doctoral candidate in chemical engineering at UC Berkeley under the supervision of Professor John Newman. Her thesis work is on property measurements and optimization of lithium-ion batteries. Sarah carries a goal to contribute to the advancement of environmentally beneficial technologies and hopes that lithium-ion batteries will soon find their way into more capable hybrid-electric vehicles. Sarah came to UC Berkeley in the fall of 2002 after graduating with honors from the University of Arizona, where she was involved with several research projects and internships as an undergraduate. Her awards include a 2005 Award for Outstanding Graduate Student Instructor, a 2003 Citation for Outstanding Teaching, and a 2000 Morris K. Udall Scholarship.
Lithium-ion batteries have received considerable attention for use in electric and hybrid-electric vehicles due to their high energy densities. These batteries must be optimized for cost, calendar life, safety, power requirements, and a wide range of operating temperatures. Mathematical modeling and property measurements can assist us in understanding these systems, and the processes that limit battery performance. These models can help to improve cell performance through optimization of cell geometry and can examine the impact of different parameters on cell performance. Accurate property measurements are necessary in order to develop accurate models and to compare the performance of different chemistries. Our work involves the characterization of electrolyte transport through the development of new and more accurate methods for measuring thermodynamic and transport properties in Li-battery electrolytes. We have adapted the method of restricted diffusion to measure diffusion coefficients in lithium-battery electrolytes using UV-Vis absorption. The use of UV-Vis absorption provides a simple alternative to more arduous experiments that may be prone to side reactions. In addition, through collaboration with the Energy Storage Group at Rutgers University, we have begun work optimizing the design of an asymmetric-hybrid system. This technology attempts to bridge the gap in energy density between a battery and supercapacitor. In this system, the positive electrode stores charge through a reversible, nonfaradaic adsorption of anions on the surface. The negative electrode is nanostructured Li4Ti5O12, which reversibly intercalates lithium.
Bree Sharratt graduated from Colorado State University, where she played four years of varsity women's golf, in 2001 with degrees in Engineering Science and Mechanical Engineering. She received her masters degree in Aeronautics and Astronautics in 2002 and has since continued on in the PhD program. After short research projects in structural health monitoring, she began her research with Prof. Reinhold Dauskardt in Stanford's Materials Science and Engineering. Ms. Sharratt's doctoral research explores the effects of interface chemistry, moisture attack, and mechanical fatigue on crack growth along polymer/inorganic interfaces. Accomplishments include the Perimeter Aviation Education Foundation Scholarship, the Robert F. Cannon Stanford 2003 Summer Fellowship, and the Techcon 2005 Best Paper in Session award. Upon completion of her degree (est. September 2006) Ms. Sharratt plans on an academic career where she will pursue research in coatings and adhesion issues for microelectronic, biomaterials, and aerospace applications.
Among the many issues integral to the success of emerging technologies, degradation of interfaces stands out as a critical factor in design and reliability assessment. Motivated by an observed anomalous near-threshold debonding phenomenon, which occurs at the interface between a model polymer layer and silicon nitride film, this work addresses relationships between interface chemistry, moisture diffusion, and subcritical interface debonding. Low measured adhesion values suggest weak interfacial bonding, which results in easy displacement of the polymer film from the substrate surface by impinging water molecules. Successful modeling of this behavior, which has important implications for interface integrity, opens the door to a systematic study of interface chemistry effects through the incorporation of organosilane molecules. These modifications affect measured adhesion values and, most importantly, moderate and even inhibit the diffusion mechanism responsible for the anomalous debonding phenomenon. Implications for design of thin-film polymer/inorganic interfaces from a defect tolerance perspective are discussed.
Tal Sholklapper graduated with B.A. degrees in Applied Mathematics and Physics from UC Berkeley. He is currently in his first year of graduate study at UC Berkeley in the Materials Science and Engineering department. He has worked at Lawrence Berkeley National Laboratory for over four years, and his research has focused on the development of Solid Oxide Fuel Cells. He has published 4 articles and has 1 patent pending.
Infiltrated electrodes have been a focus of SOFC research since the early 1960's and have become of increasing importance in recently developed high performance electrode structures. The primary interest in infiltrated electrodes is due to the larger electrode reaction areas, as compared to conventional composite cathodes, due to the small particle size (generally <100nm). Moreover, SOFC cathodes incorporating unusual catalysts can be realized because of the relaxation in compatibility issues typically found in fabricating composite cathodes. Recently we have developed a method for producing continuous nano-catalyst networks in porous SOFC electrodes with exceptional performance. An introduction to infiltrated electrodes and recent progress will be presented.
Thomas G. Smagala is currently pursuing his Ph.D. in chemistry at the University of California, Davis. He specializes in physical electrochemistry under the guidance of Professor W. Ronald Fawcett. Thomas earned a B.S. in chemical engineering / materials science and engineering at UC Davis in 2002. At graduation, he was awarded the College of Engineering Medal, the College's highest honor. He stayed an extra year and finished his M.S. in chemical engineering in 2003. Afterwards, he left Davis and worked for a while at DuPont Engineering Technology in Wilmington, DE. Thomas returned to academic life in 2004 to pursue his dream of becoming a professor, but this time as a chemist.
A novel empirical model for the diffuse double layer is found by generalizing the simple analytical equations of Gouy-Chapman theory. Two adjustable parameters are introduced into the Boltzmann equation for the exponential dependence of the ion-wall correlation functions on the diffuse layer potential. Optimal parameter values and model validation are provided by Monte Carlo simulations. Simple relationships are obtained between these empirical parameters and those commonly associated with the mean-spherical approximation. The new empiricism accurately models diffuse layer potential profiles and ion-wall correlation functions for a restricted 1:1 electrolyte in a primitive solvent.
Christopher S. Roper received the B.S.E. degree in chemical engineering from Case Western Reserve University in 2002. He is currently working toward the Ph.D. degree in chemical engineering at the University of California, Berkeley. His research focuses on Silicon Carbide deposition and processing for harsh environment MEMS and NEMS applications. He is also interested in massively parallel fabrication techniques for NEMS and other nanotechnology applications.
The ability of Silicon Carbide to tolerate harsh environments makes it a desirable material for micro- and nanoelectromechanical systems (MEMS and NEMS) devices. SiC is deposited from a single precursor, 1,3-disilabutane, on 4- and 6-inchs wafers in a low pressure chemical vapor deposition reactor. Films with high uniformity and low surface roughness are achieved in a closed boat configuration. Current film characteristics make these SiC films well-suited for chemically resistant and wear resistant MEMS coatings.