Lithium methyl carbonate as a reaction product of metallic lithium and dimethyl carbonate

To improve the understanding of passive film formation on metallic lithium in organic electrolyte, we synthesized and characterized lithium methyl carbonate (LiOCO ₂CH ₃), a prototypical component of the film. The chemical structure of this compound was characterized with nuclear magnetic resonance and Fourier transform infrared spectroscopy (FTIR), and its thermal stability and decomposition pathway was studied by thermogravimetric analysis. The FTIR spectrum of chemically synthesized compound enabled us to resolve multiple products in the passive film on lithium in dimethyl carbonate. Lithium methyl carbonate is only one of the components, the others being lithium oxalate and lithium methoxide.