RESUMO
Formation mechanisms of dendrite structures have been extensively explored theoretically, and many theoretical predictions have been validated for micro- or macroscale dendrites. However, it is challenging to determine whether classical dendrite growth theories are applicable at the nanoscale due to the lack of detailed information on the nanodendrite growth dynamics. Here, we study iron oxide nanodendrite formation using liquid cell transmission electron microscopy (TEM). We observe "seaweed"-like iron oxide nanodendrites growing predominantly in two dimensions on the membrane of a liquid cell. By tracking the trajectories of their morphology development with high spatial and temporal resolution, it is possible to explore the relationship between the tip curvature and growth rate, tip splitting mechanisms, and the effects of precursor diffusion and depletion on the morphology evolution. We show that the growth of iron oxide nanodendrites is remarkably consistent with the existing theoretical predictions on dendritic morphology evolution during growth, despite occurring at the nanoscale.
RESUMO
We report direct visualization of electrochemical lithiation and delithiation of Au anodes in a commercial LiPF6/EC/DEC electrolyte for lithium ion batteries using transmission electron microscopy (TEM). The inhomogeneous lithiation, lithium metal dendritic growth, electrolyte decomposition, and solid-electrolyte interface (SEI) formation are observed in situ. These results shed lights on strategies of improving electrode design for reducing short-circuit failure and improving the performance of lithium ion batteries.