Dr. Vyacheslav S. Bryantsev
When: November 7, 2013 at 13.00 – 14.30
Where: Skolkovo School of Management, Beijing – 1 Auditorium
SEMINAR ABSTRACT:
As one of the few possible rechargeable battery systems having specific energy within an order of magnitude of gasoline, Li-O2 batteries are a current target of research and development for electric vehicles. Electrolyte stability is an essential prerequisite for the successful development of a rechargeable organic electrolyte Li-O2 battery. Computational screening for stable solvents in Li-O2 batteries indicates that straight-chain alkyl amides are among the most stable classes of solvents to the reactions of the O2 electrode. In this seminar, I will present an overview of our current experimental and computational research activities toward the design of N-alkyl amide-based electrolytes that show improved stability toward both the Li metal and O2 electrode. In one approach we utilize fluorinated amide solvents as additives to stabilize the Li/electrolyte interface. However, this class of solvents appears to be not sufficiently stable in the O2 electrode. In another approach we employ lithium nitrate (LiNO3) as both an electrolyte salt and an SEI film stabilizing agent. Substantial improvement in the cycling efficiency is obtained through the cooperative effect of LiNO3 and dissolved O2. We provide a rationale why a higher concentration of LiNO3 has a positive effect on the degradation reactions of the O2 electrode. We also report on the use of new classes of amide solvents that show unexpected stability toward superoxide. Finally, based on the combined computational and experimental evidence we suggest a possible mechanism of regeneration of LiNO3 from LiNO2 in the electrolyte, which could be a contributing factor to the observed interfacial stability and cycling of Li metal when both LiNO3 and O2 are present.
SPEAKER INTRODUCTION:
Dr. Vyacheslav S. Bryantsev is a computational chemist with research interests in electronic structure theory, solvation models, and computational materials design for environment and energy storage. His goal is to develop a comprehensive framework for predictive modeling of functional materials for electrochemical energy storage and chemical recognition, and based on this knowledge, devise promising new materials with better properties.
Dr. Vyacheslav S. Bryantsev obtained his MS degree in chemistry with honors from Donetsk State University in 1999 and PhD degree in physical chemistry from the National Academy of Sciences of Ukraine in 2003, under the supervision of Prof. Yuri B. Vysotsky. He was a junior faculty at the Donbas National University of Building and Architecture before joining the Pacific Northwest National Laboratory, Richland, USA in 2004 as a postdoctoral research associate to work with Dr. Ben P. Hay on problems related to computer-aided molecular design and supramolecular chemistry. From 2006 to 2009 he held a position of a staff scientists in the Materials and Process Simulation Center headed by Prof. William A. Goddard III at the California Institute of Technology. Since 2009, he holds a position of a senior scientist, computational chemist at Liox Power, Inc., seeking to revolutionize energy storage through the development of advanced lithium-air electrochemical cells and systems for automotive (electric vehicles) and power industries. He is the co-author of about fifty peer-reviewed publications, one book, and two book chapters.
