Finally, we would like to briefly comment on future developments for an improved XPS analysis of complex surfaces such as SEI layers. In that case, the identification of possible  Based on the close similarity between the Li-induced decomposition of a pre-adsorbed BMP-TFSI monolayer film with the reaction between a multilayer bulk-like BMP-TFSI film and post-deposited Li, the non-chemical interaction between the graphite substrate and BMP-TFSI has no significant impact on the reaction with Li. The same seems to be true also for the difference in the initial state of Li: post-deposited Li can co-adsorb and transfer electron charge to the graphite substrate to form Li + in the monolayer case, while during interaction with bulk BMP-TFSI charge is directly transferred to the ionic liquid ions.