| Description | Mechanical Reliability of Li-ion Batteries: OperandoExperiments and Theoretical Modeling Abstract: Mechanical failure in energy materials is ubiquitous. Less understood is the mechanical
behavior of materials under chemical load, and the impact of stress on the kinetics of mass transport, charge transfer, interfacial reactions, and hence the potential and capacity of the electrochemical system. This talk focuses on the interplay of mechanics with chemical reactions in
Li-ion batteries. I will overview our effort in devising the theories of coupled diffusion and stress, stress regulated interfacial reactions, reactive flow, and corrosive fracture in recent years. I will introduce the customized operando nanoindentation which probes the continuous evolution of material states/properties during Li reactions. I will use a cathode to elaborate the use of the indentation experiments to measure the mechanical strength of electrodes at different states of charge and over cycles. I will use an anode to elaborate the use of the mechanics experiments to inform the chemistry and kinetics of Li reactions. I will introduce the use of synchrotron analytics to examine the heterogeneous chemistry and heterogeneous mechanical damage in composite
electrodes. Computational modeling integrating mechanics failure and electrochemical metrics of batteries is developed to quantify the relationship between mechanical degradation and battery performance in terms of voltage, capacity, and cyclic efficiency. Speaker Bio: Dr. Kejie Zhao joined the faculty of mechanical engineering at Purdue University in 2014. He received his Ph.D degree in Engineering Science in 2012 from Harvard, and obtained 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. The research theme of his group focuses on the chemomechanics of energy materials using experimentation and multi-scale modeling approaches. He is also working on organic electrochromics and superelastic organic semiconductors. He is a recipient of the EML Young Investigator Award, 3M Non-tenured Faculty Award, and EnSM Young Scientist Award for his research and multiple teaching awards at Purdue University. |
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