Abstract:Cyclic voltammetry and chronopotentiometry were used to study the reaction mechanism of Pb(II) and the co-deposition of Pb, Mg and Li on molybdenum electrodes in LiCl−KCl−PbCl₂−MgCl₂ melts. The diffusion coefficient of lead ions in the melts was determined by different electrochemical techniques. The results obtained by cyclic voltammetry and chronopotentiometry indicated that the underpotential deposition of lithium on pre-deposited Pb leads to the formation of a liquid Li−Pb alloy, and the Mg−Li−Pb alloys are formed after the addition of MgCl₂. X-ray diffraction confirmed that in the Mg−Li−Pb alloy, PbLi₃, Mg₂Pb and Li₇Pb₂ phases exist by galvanostatic electrolysis at 6.21 A/cm² for 2 h at 873 K and the phases can be controlled by changing the concentration of PbCl₂ and MgCl₂.

Key words: LiCl−KCl system; cyclic voltammetry; chronopotentiometry; diffusion coefficient; molten salts electrolysis