(red) forms a stable layer on the anode, bound by strong electrostatic forces to multi-coordination state Li + , which increases in mass density as the simulation progresses. This presents the start of crystallization of Li 2 CO 3 , identified by X-ray photoelectron spectroscopy (XPS) to be one of the main components of the inner inorganic layer. Ethene gas (gray), one of most abundant gases trapped in the SEI regardless of the type(s) of carbonate the electrolyte is based on, accumulates between the inorganic and organic layers.