MAE Seminar: Mechanics of Redox Active Materials

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 briefly introduce the customized operando nanoindentation and its use to inform the thermodynamics and kinetics of Li reactions in amorphous Si. 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 introduce 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.

Bio: Kejie Zhao is an associate professor of mechanical engineering at Purdue University. He received his Ph.D. degree in engineering science in 2012 from Harvard, 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 2012-2014. His group focuses on the chemomechanics of redox active materials, including batteries, electrochromic polymers, electrochemical transistors and molecular crystal semiconductors. He is a recipient of the NSF CAREER Award, Extreme Mechanics Letters Young Investigator Award, 3M Non-tenured Faculty Award, Energy Storage Materials Young Scientist Award, and James W. Dally Young Investigator Award from the Society for Experimental Mechanics for his research and multiple teaching awards at Purdue University.