Electrodeposition of Ti in molten AF–ACl–A₃TiF₆ (A = Li, Na, K)

Electrochemical behaviors of Ti(III) ions and electrodeposition of Ti were investigated in molten AF–ACl–A 3 TiF 6 (A = Li, Na, K) at 973 K. Redox currents corresponding to Ti(III)/Ti(0) and Ti(IV)/Ti(III) reactions were observed by cyclic voltammetry. The redox potentials of the reactions with reference to Cl 2 /Cl − and F 2 /F − were most positive for the Li system, followed by the Na system, and most negative for the K system. The differences in the potential can be explained by the interactions of alkali cations and F - ions; smaller cations interact more strongly with F − , resulting in a weaker interaction between Ti(III) ions and F - ions. As a result, the electrochemical stability of TiF 6 3− decreased. The electrodeposited Ti was confirmed to be crystalline by XRD, and the orientation of the Ti crystals differed depending on the molten salt.