The formation of bi-dioxolylidene is predicted to be less kinetically favorable than that of LFEO. The dimerization reaction has an energy barrier that is considerably higher than many major SEI formation pathways, implying that bi-dioxolylidene should not be a significant product. The formation of the carbene monomer, on the other hand, is plausible. Using the Eyring equation, the addition of CO 2 to Li + EC 2-with a 0.20 eV barrier has a predicted rate coefficient roughly 70 times lower than that of the shoulder ring-opening of Li + EC 2-with a 0.09 eV barrier. However, dioxolylidene formation could be significant if CO 2 is abundant, a plausible scenario considering that CO 2 can form at either the anode or the cathode in Li-ion batteries. On this basis, we predict that while LFEO, Li + OCH 2 CH 2 O 2-, and CO will be favored, dioxolylidene should at least form as a short-lived minority intermediate (considering the general reactivity of carbenes).