In the F1s region, Li deposition leads to an additional peak at about 685.9 eV (FTFSI,dec-1, yellow), while except for a considerable intensity loss there is no significant change in the TFSI-related peak at 689.4 eV (FTFSI+Li, cyan). Based on its BE, the new peak could be due to the formation of LiF, whose BE was reported to be in the range of 685.00.2 eV. Considering that at RT desorption of BMP-TFSI is negligible, the total loss in F1s intensity of about 40% upon Li deposition was attributed to the formation and desorption of F-containing, but N-free (see above) reaction products such as C2F4, which are volatile already at room temperature. Nevertheless, most of the remaining F1s intensity is in the TFSI-related peak, indicating that under these conditions the formation of adsorbed stable reaction products is still slow.