Mechanics of Redox Active Materials

Speaker: Dr. Kejie Zhao - Purdue University, West Lafayette, Indiana
Date: Nov 4, 2022; Time: 2:30 PM Location: UTEB 150

Abstract: This talk focuses on the interplay of mechanics with chemical reactions across multiple scales in redox active materials. I will use battery materials to introduce how electrochemistry induces deformation, stresses, and mechanical damage, and how mechanical stresses regulate charge transfer, mass diffusion, capacity, and voltage. I will introduce the customized operando nanoindentation and its use to inform the thermodynamics and kinetics of Li reactions in amorphous Si. I will introduce in-situ optical microscopy as a laboratory tool to map the spatial composition heterogeneity in a solid-solution cathode. We develop computational models by integrating electrochemical response and mechanical failure in battery cells. The multiscale modeling will discuss the heterogeneous chemical activity and heterogeneous mechanical damage in commercial composite electrodes. I will discuss corrosive fracture in single particles, dynamic equilibrium in the particulate network, and the relationship between mechanical damage and electrochemical metrics of voltage, capacity, and cyclic efficiency in cells.

Biographical Sketch: Dr. Kejie Zhao is an Associate Professor of Mechanical Engineering and B.F.S. Schaefer Scholar at Purdue University. He received his Ph.D. degree in Engineering Science in 2012 from Harvard University, and his bachelor’s and master’s degrees from Xi’an Jiaotong University in 2005 and 2008, respectively. He worked as a postdoctoral associate at MIT in 2012-2014. His group focuses on the chemomechanics of electrochemically active materials using experimentation and multi-scale modeling approaches. He is a recipient of the NSF CAREER Award, EML Young Investigator Award, 3M Non-tenured Faculty Award, EnSM Young Scientist Award, and James W. Dally Young Investigator Award from the Society for Experimental Mechanics. He is a fellow of ASME.