In the mechanism for LFEO formation identified in Figure , a byproduct is the deprotonated EC species Li + EC H -. We suspected that this byproduct would be highly reactive and would likely decompose. Indeed, we found (Figure ) that Li + EC H - can open at the waist bond with an extremely low barrier (∆G ‡ = 0.02 eV), forming lithium vinyl carbonate. We note that lithium vinyl carbonate has previously been identified as an SEI product, though its formation mechanism has not been thoroughly studied. Therefore, not only is the formation of LFEO plausible on the basis of the low reaction barriers identified, but LFEO formation can potentially help to explain the formation of another SEI product.