Electrochemical behavior of Pb(II) in LiCl−KCl−MgCl2−PbCl2 melts on
Mo electrode
Mo electrode
(Key Laboratory of Superlight Materials and Surface Technology (Ministry of Education),
College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China)
College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China)
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