Christopher S. Johnson

Chemical Sciences and Engineering Division, Argonne National Laboratory

Wednesday, April 24 from 3:15–4:30 p.m. in the Perlstein Hall Auditorium

Abstract

Because of their high-gravimetric capacities, use of Si-containing anodes in Li-ion batteries can lead to a big jump in energy densities. The control of lithium consumption, however, is a big obstacle for these cells, and many strategies are emerging to address the problem of Li inventory. We search for solutions on the subject from two fronts. The first is to understand the lithium inventory via utilization of a quasi-RE/CE thick LiFePO4 in a Si-type full cell. In this study we show the effectiveness of LiFePO4 as a diagnostic tool in order to assay the quantity of Li consumption in a full cell as marked by the percent loss of lithium per cycle via SEI growth and/or SEI consumption and re-formation. This approach allows the Li content to be followed during cycling without Li metal or layered oxide cathode complications (i.e., non-controlled voltage shifts). The second topic focuses on practical solutions to introduce high contents of Li into the cell in the easiest, most straightforward way. We take the approach of designing cathodes and utilizing cathode blends wherein sacrificial Li is introduced into the cell. In these cases, greater energy densities can be realized from higher retained cathode capacity, and cycle life is dramatically improved.

 Short Biography

Chris Johnson is currently a senior chemist and group leader at Argonne National Laboratory, specializing in the research and development of battery materials and battery systems with 27 years of experience. He is known worldwide for his development of state-of-art lithium-ion battery cathode materials. He holds a B.S. in chemistry from the University of North Carolina at Chapel Hill and a Ph.D. in chemistry from Northwestern University. He has extensively published and has 25 issued United States patents in the battery field. He received the research award from the International Battery Association in 2006 and an R&D-100 award for the commercialization of lithium battery materials in 2009. He is past-chair of the Electrochemical Society Battery Division and currently the International Battery Association president. Johnson is the 2018 recipient of the University of Chicago Argonne Distinguished Scientist Award and is a fellow of the Electrochemical Society.