An in-situ Raman study of the oxygen reduction reaction in ionic liquids

摘要

In-situ Raman spectroscopy is applied, for the first time, to elucidate the reaction products of oxygen reduction in two types of ionic liquids: 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C2mimTFSI) and 1- butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (Pyr_(14)TFSI). The degradation of C_2mimTFSI by superoxide attack is evidenced by the appearance of bands characteristic of amide and carbonate compounds. On the contrary, Pyr_(14)TFSI is found to be resistant towards degradation. It is observed that superoxide is the first product of oxygen reduction in Pyr_(14)TFSI, and the formation of Li_2O_2 is observed at longer times.