Electrolytic deposition of lithium from non-aqueous solutions

This paper describes a study of the deposition of lithium from lithium salts (LiNO3, LiCl, and LiClO4) in organic solvents (CH3CN, (CH3)2SO, HCONH2, HCON(CH3)2, CH3CON(CH3)2, and THF) using the potential-sweep technique. The current efficiency for lithium deposition was found to depend on both the solvent used and the particular anion in the electrolyte. In CH3CON(CH3)2, (CH3)2SO, and HCON(CH3)2 solutions, the current efficiency for lithium deposition increased in the order: lithium chloride < lithium perchlorate < lithium nitrate whereas in CH3CN it increased on addition of chloride. Addition of water to the LiNO3-DMF solution also increased the current efficiency for lithium deposition. The solution which gave the highest efficiency was LiNO3 in CH3CON(CH3)2, in which efficiencies higher than 70% were obtained. The lithium metal deposited electrolytically from the LiNO3-HCON(CH3)2 solution consisted of fine grains and had a high degree of crystallinity with very smooth deposit surfaces.