Electrochemical Behavior of Dysprosium Complex in Potassium Bis(trifluoromethylsulfonyl)Amide Melts

摘要

From the standpoint of energy conservation, the development of a recovery process for rare earth metals with reduced energy consumption is desired. In previous investigations, we demonstrated the recovery of Nd metal using low-temperature molten salts (LTMSs), because an LTMS has many useful physicochemical properties such as a wide electrochemical window, low liquid-phase temperature, and high ionic conductivity. In our findings, the reduction process of Dy(III) proceeded in two steps by way of Dy(II), [Dy(III)+e~-→Dy(II), Dy(II)+2e~-→Dy(0)] in [NTf_2~-] based ionic liquids (ILs), because [Dy_((III))(NTf_2)_5]~(2-) and [Dy_((II))(NTf_2)_4]~(2-) in ILs were confirmed by Raman spectroscopy and DFT calculations. However, there were no information about the detailed solvation conformations of Dy(II) and Dy(III) in K[NTf_2] melts. Therefore, we have investigated the electrochemical behavior of Dy(II) and Dy(III) in K[NTf_2] melts.