In situ and operando characterization of battery materials
Lithiation of a Germanium particle from a solid electrolyte, operando FIB-SEM
The rapid expansion of the electric vehicle market has created a continuous demand for increasing the energy density of Li-ion batteries. One promising approach is the use of alloy-type anode materials, such as silicon (Si), germanium (Ge), and tin (Sn), which offer significantly higher capacities compared to graphite (372 mAh/g). For example, Si, Ge, and Sn have theoretical capacities of 3579 mAh/g, 1600 mAh/g, and 994 mAh/g, respectively. However, these materials undergo approximately 300% volume changes during charging and discharging, which can lead to particle fracture and electrode delamination from the current collector, resulting in a rapid loss of specific capacity. During battery cycling, the insertion and removal of Li ions into and from the active materials are accompanied by dynamic changes in phase, morphology, microstructure, strain, and stress. Understanding these dynamic processes in high-capacity electrode materials is crucial for advancing the development of high-energy-density Li-ion batteries. In this project, we will study the dynamics of high-capacity electrode materials during Li-ion insertion and removal, utilizing advanced in situ and operando characterization technologies such as transmission X-ray microscopy (TXM), X-ray diffraction (XRD), focused ion beam-scanning electron microscopy(FIB-SEM), and X-ray absorption spectroscopy (XAS). These fundamental insights will provide a solid foundation for guiding 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.