Stepwise annealing up to 450 K results in little change. Only upon annealing to 500 K we find some intensity transfer from the high-BE FTFSI+Li peak (cyan) to the low-BE FFTFSI,dec-1 peak (yellow), indicating that at this temperature another reaction pathway opens up. Annealing to 650 K leads to the complete disappearance of the FTFSI+Li peak, together with a much smaller intensity loss (-10%) in the low-BE FTFSI-dec-1 peak. We cannot decide from these data, however, whether the desorption of the TFSI-related species occurs directly or whether part of them convert into the peak FTFSI,dec-1 species, together with desorption of the FTFSI,dec-1 related species. Together with these intensity losses, the FTFSI,dec-1 peak shifts also to slightly higher BE, which can result either from a modification of the species underlying the FTFSI,dec-1 peak or from decomposition of species in the previous FTFSI+Li peak. Finally, upon annealing to 700 K, also this latter peak disappears completely. The identity of possible reaction products species resulting in the two F1s peaks will be discussed in more detail in section 3.2.2.