Lithium
methyl carbonate (LMC) is synthesized in a single step and investigated
as a coating material for Li protection. The LMC layer can be formed <i>in situ</i> during Li plating on Cu foil. The chemical and crystal
structure of the ∼1 μm thick coating is confirmed, which
remains intact during lithium cycling. SEM also confirms the dissolution
of the LMC layer after being transferred into the commercial LiPF<sub>6</sub>-carbonate electrolyte. Presaturating the electrolyte with
LMC powder prevents the dissolution of the LMC coating layer, which
improves the Li plating/stripping Coulombic efficiency from 90.5%
(bare Cu in commercial electrolyte) to 96.1% at 0.5 mA cm<sup>–2</sup> and 1 mAh cm<sup>–2</sup>
