Electrochemical formation of Mg–Li alloys at solid magnesium electrode from LiCl–KCl melts

Abstract

This work presents a study on electrochemical formation of Mg–Li alloys on solid magnesium electrode in a molten LiCl–KCl (50:50, wt.%) system at 753 K. Cyclic voltammetry and open circuit chronopotentiometry were employed to investigate the electrode reaction. For an Mg electrode, the electroreduction of Li(I) takes place at more positive potential values than at the inert W electrode indicating the formation of Mg–Li alloys. X-ray diffraction and scanning electron microscopy (SEM) analysis of the deposits indicated that α, α + β and β phases Mg–Li alloys with the thickness of 182, 365 and 2140 μm were obtained by potentiostatic electrolysis at −2.26, −2.30 and −2.39 V (vs. Ag/AgCl), respectively. The results showed that formation of α, α + β and β phases Mg–Li alloys could be controlled by applied potential. Lithium contents of Mg–Li alloys can be decreased via electrolysis at low temperature followed by thermal treatment at higher temperature. Mg–Li alloys with excellent mechanical properties can be produced by this novel method.