Abstract:Li2CO3 was used as raw materials to prepare lithium metal in LiCl-LiF pure lithium salt system at 680 ℃ by molten salt electrolysis method. Electrochemical behavior of Li2CO3 on tungsten electrode was analyzed by electrochemical methods such as cyclic voltammetry and chronopotentiometry. The results show that lithium metal reduction on tungsten electrode is one step electron reversible reaction process. There is an oxidation peak before chlorine emission peak, which is caused by addition of Li2CO3 under electric field. Li2CO3 decomposes into lithium oxide and carbon dioxide. Oxygen ions are discharged to produce oxygen before chlorine emission peak. Diffusion coefficient of lithium ion drops from 1.98×10-8 cm2/s to 0.82×10-8 cm2/s after addition of 1%Li2CO3 to LiCl-LiF molten salt system, and the minimal reduction current density rises from 0.28 A/cm2 to 0.59 A/cm2. The electrochemical reduction process of lithium on tungsten electrode is controlled by diffusion.