Structure and Solution Dynamics of Lithium Methyl Carbonate as a Protective Layer For Lithium Metal

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 in situ 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 LiPF6-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–2 and 1 mAh cm–2.