This difference may, however, be related to the lower amount of Li post-deposition on the monolayer film as compared to the multilayer film. The TFSI-related signal at 400.0 eV also seems to shift to slightly higher BE (400.5 eV) upon Li deposition and loses intensity, although much less than the BMP-related signal. As discussed already in section 3.1.1, we had shown recently in a series of stepwise increasing Li doses that an interaction / reaction product between BMP and Li appears at this position (NBMP,dec1, green), which upon increasing Li deposition stepwise replaces the original TFSI-related peak. In fact, LiNC9H20 and LiFNC9H20, species, where Li or LiF interact with BMP, were found to exhibit BEs exactly in this range. After 3.6 ML Li deposition, this process is almost completed. Furthermore, two new peaks appear at 398.2 eV and 398.9 eV, which were assigned to species resulting from the reaction between Li and TFSI (398.9 eV: NTFSI,dec-1 (blue-yellow) and 398.2 eV: NTFSI,dec-2, yellow). This assignment was supported also by the intensity balance of the BMP-related peaks and the TFSI-related peaks during stepwise increasing Li deposition, which showed a constant total intensity for each of these species. Hence, losses due to desorption of Ncontaining species and thus the formation of volatile, N-containing reaction products during Li deposition must be small.