Figure shows scanning electron microscopy images (SEM) of the resulting lithium layer, after galvanostatic electrodeposition at -1 mA/cm 2 up to 0.74 C/cm 2 (expected to yield 1 µm of electroplated lithium at 100% Faradaic efficiency) for both salts at different concentrations of the water additive. The insets of the figure show digital photos of the sample after rinsing with anhydrous Propylene Carbonate (PC) and vacuum drying. It is clear from the figure that the morphology of the deposit is governed by the concentration of the water additive and that the deposition qualitatively follows the same trend irrespective of the used salt, going from a mossy, to a columnar morphology. The essential role of water, rather than the salt, is also apparent in the color progression of the samples, which evolves from grey/black, to blue, to yellow in both cases. In fact, we will show later that the presence of water is a prerequisite, as we find that there is no adhesion for the deposit in the case of the fully dry solvent. Additional (cross-sectional) SEM, atomic force microscopy (AFM) images, and V-t traces of these experiments are provided in SI-1, where we note that it was more difficult to grow from the LiClO4 than from the LiTFSI electrolyte. As this typically results in black spots that wash away with the PC rinse and a thinner layer than expected based on the total passed charge, we focus on the LiTFSI salt in the remainder of the paper.