STABILITY AND ELECTROCHEMISTRY OF LITHIUM IN ROOM-TEMPERATURE CHLOROALUMINATE MOLTEN-SALTS

Addition of protons to buffered neutral AlCl3:MEIC:LiCl (MEIC = 1-methyl-3-ethylimidazolium chloride) melts allows elemental lithium to be deposited and stripped at a 250 mum tungsten electrode. Chronopotentiometric studies performed at current densities from 0.16 to 3.06 mA cm-2 show minimal overpotentials for lithium deposition and stripping. When the lithium is stripped immediately after deposition, the stripping to deposition efficiency approaches 80%; however, when the deposited lithium is allowed to contact the electrolyte at open circuit for several minutes, the efficiencies drop rapidly due to the reaction of lithium with the melt. In basic (chloride-rich) AlCl3:MEIC melts, elemental lithium appears to be stable for long times with and without the addition of protons. In addition, the maximum lithium anodization current density achieved in basic melts is higher than the buffered neutral melts.