Electrodeposition of Niobium from 1-Butyl-1-Methylpyrrolidinium bis(trifluoromethylsulfonyl)amide Ionic Liquid

Electrodeposition of Niobium from the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py1,4]TFSA) was investigated at various temperatures ranging from RT to 170 °C. The effect of addition of salts such as LiF and LiTFSA on the quality of the Nb deposits was also investigated. Cyclic voltammetry was employed to examine the electrochemical behaviour of NbF5 alone in [Py1,4]TFSA and of mixtures of NbF5 with LiF (or NbF5 with LiTFSA) in [Py1,4]TFSA. Potentiostatic electrolysis was performed to deposit Nb. The obtained Nb deposits were characterized using SEM and XRD. The results show that Nb can be electrodeposited along with nonstoichiometric compounds of niobium subfluorides from NbF5/[Py1,4]TFSA. Cubic facets were seen in the SEM analysis of the Nb deposit from (NbF5 + LiTFSA)/[Py1,4]TFSA. Glancing Angle XRD analysis of the deposits obtained from (NbF5 + LiTFSA)/[Py1,4]TFSA and (NbF5 + LiF)/[Py1,4]TFSA at 170 °C proved the existence of elemental Nb in addition to oxides of Nb. The addition of either LiF or LiTFSA to NbF5/[Py1,4]TFSA significantly enhanced the quality of the Nb deposits.