Investigation into cathodic reduction process of Yb(III) ion in (LiF-YbF3)eut.-Yb2O3 molten salt system

The electrochemical behavior of Yb3+ ions is investigated through cyclic voltammetry and chronoamperome-try/potentiometric methods on the surface of a W/Ni working electrode in a (LiF-YbF3)eut-Yb2O3 molten salt system. The results show that the reduction of Yb3+ ions is completed by two-step quasi-reversible processes of Yb3+/Yb2+ and Yb2+/Yb on the W and Ni cathodes in LiF-YbF3 and (LiF-YbF3)eut-Yb2O3 molten salt systems at 1223 K; and the diffusion coefficients of Yb3+ are 5.45 x 10-4 cm2 s-1 and 3.75 x 10-3 cm2 s-1, respec-tively. The addition of Yb2O3 can improve the electrochemical activity of Yb3+ in the LiF-YbF3 system. The crystallization of Yb3+ ions are through three-dimensional instantaneous and continuous nucleation on the W and Ni electrodes in the (LiF-YbF3)eut-Yb2O3 molten salt system, respectively. The reduction activity of Yb2+ ions on the Ni cathode is stronger than on the W cathode, which is beneficial to alloying. The Ni2Yb alloy can be prepared by constant voltage electrolysis with Ni as a consumable cathode in the (LiF-YbF3)eut-Yb2O3 molten salt system.

Automated summary

The electrochemical behavior of Yb3+ ions was investigated in a (LiF-YbF3)eut-Yb2O3 molten salt system, and it was found that Yb3+ ions undergo two quasi-reversible processes on W and Ni cathodes. The addition of Yb2O3 improves the electrochemical activity of Yb3+. The crystallization of Yb3+ ions occurs through three-dimensional instantaneous and continuous nucleation on W and Ni electrodes, respectively. The reduction activity of Yb2+ ions on the Ni cathode is stronger, which enables the preparation of the Ni2Yb alloy.