Electrodeposition of magnesium in eutectic (58-42mol%) containing vatious MgCl2 concentrations was studied using tungsten as the cathode. The temperature was varied above and below the melting point (983K) of magnesium. Techniques such as cyclic voltammetry, chronopotentiometry and chronoamperometry were used to characterise the system. For all of the electrochemical techniques, macroscopic growth of the solid magnesium deposit was observed. Liquid magnesium deposits were found to grow without giving rise to any significant increase in surface area. This could be attributed to lithium co-deposition and the formation of Li-Mg liquid solutions, and differences in the interfacial properties of the cathodic deposits obtained in each case. The deposition of lithium on pre-deposited magnesium led to the formation of Li-Mg solid alloys or to a liquid Li-Mg solution at temperatures below or above the melting point of magnesium, respectively. The diffusion coefficient of magnesium ions was determined using various electrochemical techniques (table 102). The values obtained showed the effect of macroscopic growth of the deposit in the case of solid magnesium deposits.

Electrodeposition of Magnesium from the Eutectic LiCl-KCl Melt. A.M.Martínez, B.Børresen, G.M.Haarberg, Y.Castrillejo, R.Tunold: Journal of Applied Electrochemistry, 2004, 34[12], 1271-8

Table 102

Diffusivity of Mg in LiCl-KCl Melt