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Physics Colloquium

Speaker: Likun Zhu Location: LD 010

Understanding the dynamics of high capacity Li-ion battery electrode materials during cycling using in-situ and in-operando technologies

Abstract:
Generally, battery technology has advanced at a slightly slower rate than the applications that use renewable energy, such as electric vehicles. It is a continual race to further develop the two key elements of capacity and recharge rate, which determine how much energy a battery can store and how long it takes to fully recharge. One promising direction is the use of alloy-type anode materials in Li-ion batteries such as silicon (Si), germanium (Ge) and tin (Sn) because of their much higher capacity compared to graphite (372 mAh/g). For instance, Si, Ge and Sn have theoretical capacity of 3579 mAh/g, 1600 mAh/g and 994 mAh/g respectively. However, these materials have about a 300% volume change upon charging/discharging, which could result in particle fracture and electrode delamination from the current collector, thereby leading to rapid loss of specific capacity. During battery cycling, Li ions are inserted into or removed from the active materials accompanied by the dynamic changes of phase, morphology, microstructure, strain, stress, etc. Understanding the dynamic processes of high capacity electrode materials during Li ion insertion and removal is essential to the development of high energy density Li-ion batteries. In this talk, I will present the dynamics of high capacity electrode materials during Li ion insertion and removal using in-situ and in-operando technologies, such as synchrotron transmission X-ray microscopy, synchrotron X-ray diffraction, and focused ion beam scanning electron microscopy. These fundamental understandings will lay a solid foundation to guide the design and fabrication of high capacity Li-ion battery electrode materials, thereby facilitating the development and commercialization of high energy density batteries for energy storage applications.

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Refreshments will be served in LD 154B from 3:00-3:30pm.