Imidazolium ionic liquids, EMIIm vs. EMIBeti: electrochemical stability on glassy carbon aluminum, and the stainless steels 316 and 304

摘要

The electrochemical stability of the ionic liquids EMIm and EMIBeti on several electrode materials was determined. The purpose of the study was to compare anion effects in a solvent free system. The EMIBeti ionic liquid is 0.2 V more stable onglassy carbon, liikely due to the decreased basicity of the anion. With cycling to positive potentials in either ionic liquid, aluminum formed a passivation layer while the stainless steels underwent both passivation and corrosion. The stainless steel 304 is less stable than the 316 alloy. In contrast to the lithium salt analogs in propylene carbonate (PC), low corrosion currents (<1μA/cm{sup}2 at 30 min.) were observed in these ionic liquids at 2.2 V vs. Ag (5.2 V vs. Li/Li{sup}+). With the addition of10 weight percent PC to EMIIm, however, a large corrosion current at 1.2 V vs Ag is observed, consistent with previous reports.