Determination of adsorbed species in the surface hydrolysis of SOF/sub 2/ on activated alumina

Abstract

The nature of the species adsorbed in the hydrolysis of SOFZ on activated alumina has been investigated using spectroscopic XPS and FTIR techniques. XPS technique proved to be a convenient tool for determining the amount of adsorbed species, especially when they are strongly bonded. The amount of fluorine detected by XPS confirmed its strong interaction with alumina, although the formation of an aluminafluorine complex was not observed. With regards to the adsorbed sulfur complexes, the S 2p XPS binding energy (BE) associated with the features of the FTJR spectra (around 1000-1200 cm-') suggests the presence of both chemisorbed SO3 (sulfite) and SOZF (fluorosulfite) species on alumina. Lastly, the decreasing amount of oxygenated species detected by XPS suggests that the presence of adsorbed fluorine has a significant impact on the retention capability of alumina toward moisture.

Study of the Initial Stage of Solid Electrolyte Interphase Formation upon Chemical Reaction of Lithium Metal andN-Methyl-N-Propyl-Pyrrolidinium-Bis(Fluorosulfonyl)Imide

“…Next turning to the S 2p spectra, the presence of a broad S 2p peak at 169 eV suggests the presence of oxidized sulfur species. , Previous studies have shown that SO 2 F – species are observed at 169.5 eV in the S 2p XPS spectra. , On the basis of these reports as well as the simulated reaction mechanism, which predicts an SO 2 F species as a degradation product, we can assign the S spectra to a surface bound SO 2 F species.…”

“…After a reaction period of 4 h, peaks which can be attributed to LiF, LiOH, and a SO 2 F , species as well as species containing N + and N – (assigned to surface confined [C 3 mPy + ] and [FSI – ]) are present on the surface. Similar results are observed over 7 to 18 day samples, albeit with varying peak intensities, suggesting that the quantity of these species changes during the course of the chemical reaction.…”