PNNL

Abstract

The understanding of lithium (Li) nucleation and growth is still limited due to the lack of imaging tools that can provide the information of this dynamic process. Herein, we report an operando reflection interference microscope (RIM) that enables the real-time imaging and tracking the individual Li nucleation process with high spatial and temporal resolutions. Both growth and stripping processes of Li nuclei show two distinct stages. In addition, we find that there are no Li nuclei generated before the overpotential reaches its minimum value. More importantly, the formations and growth of the initial Li nuclei are not the same, which strongly indicates the localized surface electrochemical environments, including solid electrolyte interphase, ion concentration, and surface energy, determine the Li nucleation and growth. To further illustrate this effect, we extract the localized overpotential map using the particle size dynamics obtained from the RIM and the Barton’s model for the first time.