ELECTROCHEMICAL BEHAVIOR OF COPPER IN AMMONIUM IMIDE TYPE ROOM TEMPERATURE MOLTEN SALT

摘要

The redox behavior of copper species in an "ammonium imide" room temperature molten salt was examined in order to clarify the applicability of the salt to the electroplating media of various metals. Trimethyl-n -hexylammonium bis(trifluoromethanesulfonyl)-amide (TMHA-Tf_2N), having an electrochemical window of 5.6 V (50 deg C), and corresponding copper(II) salt were synthesized. In TMHA-Tf_2N media monovalent copper ion, Cu(I), was stable and Cu metal was oxidized, or corroded, in the presence of Cu(II) species. Cathodic electrodeposition of copper metal and anodic dissolution of it were, thus, one-electron reaction and their current efficiencies were almost 100 percent.