The identified elementary mechanisms to LFEO and bidioxolylidene involve steps that are predicted to be competitive with other known SEI formation processes. Both mechanisms rely on Li + EC 2-, which can form easily at low potentials. After breaking the shoulder bond, the ring-opened Li + EC 2-is known to decompose unimolecularly to Li + OCH 2 CH 2 O 2-and CO with a predicted energy barrier between 0.09 eV and 0.22 eV 51 depending on the level of theory used. Considering that the necessary precursor to LFEO formation, Li + EC, should be present in abundance during early SEI formation, this implies that LFEO could actually be a significant product during early SEI formation at low potentials.