Hosted by: Dong Su

Dynamic materials processes (phase transformations, interfacial reactions, mechanical degradation, etc.) play major roles in determining the lifetime and performance of next-generation electrochemical energy storage systems. To develop batteries with improved safety, energy density, and lifetime, it is critical to understand transformation mechanisms and degradation processes within these devices. In my group, multiscale in situ techniques are used to reveal reaction mechanisms and interfacial transformations in energy storage materials to guide the development of better batteries. Our recent work has used a combination of in situ transmission electron microscopy (TEM) and in situ x-ray diffraction (XRD) to elucidate transformation pathways when high capacity electrode materials react with lithium vs. sodium for Li-ion and Na-ion batteries. Cu2S-based electrodes, for instance, show similar global transformations during reactions with lithium and sodium, but the nanoscale reaction pathways differ significantly, which influences the electrochemical performance. Other work to be presented is focused on using X-ray spectroscopy and imaging methods to understand reaction mechanisms at nanoscale interfaces, as well as strain evolution within individual nano-to-micro particles. Together, these results demonstrate the importance of developing in situ techniques to understand atomic-to-macroscale dynamic processes in energy materials.