Electrodeposition is used in various manufacturing processes for creating metal, colloid, and polymer coatings on conductive substrates. The process also plays an important role in electrochemical storage technologies based on rechargeable batteries, where it must be carefully managed to facilitate stable and safe operations at low operating temperatures, high rates, and over many cycles of charge and discharge. A successful electrodeposition processes requires fast transport of charged species (e.g. ions, particles, & polymers) and stable redox reactions at liquid-solid interfaces. This talk considers the stability of electrodeposition of reactive metals on planar electrodes with an emphasis on its role in enabling next-generation batteries in which metallic lithium or sodium serves as the electrode. Such batteries have been argued to offer step-change improvements in electrochemical storage technology over todays’s state-of-the art lithium ion batteries and are under active investigation worldwide for high-energy, portable energy storage solutions in multiple fields. Beginning with analyses of ion transport processes and stability of electrodeposition in a so-called structured electrolyte, the talk will discuss strategies for rationally designing electrolytes and electyrtochemical interphases for stabilizing deposition of reactive metals. The talk will also discuss contemporary efforts to evaluate these approaches using electrochemical and visualization studies.