Analysis of Electrochemical Behavior of (LiF–CaF₂)_eut.–Yb₂O₃ System with (Ni²⁺/Ni) Internal Reference Electrode

The transient electrochemical behavior of the Yb (III) ion (Yb 3+ ) on the surface of a Ni working electrode in a (LiF–CaF 2 ) eut. –Yb 2 O 3 molten salt system was analyzed using a three-electrode system with a reversible (Ni 2+ /Ni) internal reference electrode and Pt external reference electrode. The (Ni 2+ /Ni) internal reference electrode exhibited good stability and reliability, and provided results that were consistent with those of the Pt external reference electrode. The (Ni 2+ /Ni) electrode also had a wider measurement window for analysis of the electrochemical process than that of the Ni working electrode. Cyclic voltammetry, square wave voltammetry, chronopotentiometry, and chronoamperometry were used to analyze the Yb 3+ ion in the (LiF–CaF 2 ) eut. –Yb 2 O 3 (0.03 mol%) system. It was confirmed that the Yb 3+ ion was reduced according to Yb 3+ + e → Yb 2+ and Yb 2+ + 2 e → Yb, and the electrode reaction process was quasi-reversible and controlled by diffusion. Moreover, the Yb 3+ ion alloyed with the Ni electrode to form a Ni–Yb alloy.