Assistant Professor Don Siegel has been selected by the National Science Foundation as a CAREER Awardee, based on his research proposal entitled "CAREER: First-Principles Modeling of Gas Evolution Reactions in Lithium Batteries."
The Faculty Early Career Development (CAREER) Program, which exists within the National Science Foundation, offers awards to junior faculty who have exemplified the ideal teacher-scholar dynamic. In other words, the program advocates research in unison with education as a means to further a specific mission. The grant differs from other NSF awards, in that the stakes are set higher. Projects are expected to be new and innovative, and there is greater focus placed on education as well as outreach.
Abstract: "The primary objective of this project is to characterize the reaction mechanisms associated with electrolyte decomposition within the cathode of Li-air and Li-ion batteries. These reactions occur at the electrolyte/cathode interface, and have major implications for the safety, longevity, and efficiency of these systems. Nevertheless, they have received relatively little attention compared those occurring on the opposing electrode, i.e., at the electrolyte/anode interface. This bias, coupled with the inherent complexity of the electrolyte/cathode interface, has resulted in limited understanding of cathode-mediated decomposition mechanisms. This project will close this knowledge gap by simulating the electrolyte/cathode interface at the atomic scale, under conditions similar to those found in a realistic battery, using state of the art ab intio molecular dynamics and dispersion-corrected Density Functional Theory simulations, in concert with a design of experiments approach that will isolate individual contributions from the electrode potential, variations in the electrode surface, and the presence of solvated (salt) ions.
In high-capacity Li-air batteries, decomposition of the electrolyte results in the formation of stable compounds (e.g., Li carbonate), which require high overpotentials to recharge and which release CO2 rather than O2. In Li-ion batteries, reactions at the electrolyte-cathode interface can lead to the accumulation of gaseous species such as CO2, H2, etc., which when vented to the atmosphere release highly flammable solvent vapor. By revealing the elementary steps associated with these decomposition processes the PI will facilitate the development of rational strategies to minimize their occurrence, leading to more efficient and safe batteries. The simulations will advance understanding of the interplay between structural, electronic, thermodynamic, and kinetic aspects of protype electrolyte-electrode interfaces. These interfaces are pervasive in electrochemical systems such as fuel cells and photo-electrochemical cells.
In addition, this project will translate research outcomes into energy-themed educational activities for students at the grade school, collegiate, and professional levels. At the grade-school level the PI will engage 7th-8th grade girls by developing a week-long focus group on "Materials for Energy" for the UM Girls in Science and Engineering Summer Camp. At the collegiate level, the PI will extend his existing course, "Atomistic Computer Modeling of Materials," by developing new lectures and laboratory exercises that describe methods for introducing bias potentials into electronic structure calculations, and their importance in modeling electrochemical systems. Finally, at the professional level, a new module on "Battery Safety" will be created and distributed to participants in the PI's short course for practicing automotive engineers, "Introduction to Electrical Energy Storage." The impact of these activities will be assessed annually -- and in selected cases over a multi -year term -- using web-based and social media."
For more information, visit the NSF Award Abstract page.