Room temperature molten salt as medium for lithium battery

Due to the wide electrochemical window and high ionic conductivity, the 1-m ethyl-3-ethylimidazolium chloride (MeEtImCl) room temperature molten salt ( RTMS) was investigated as the medium for lithium battery in the present wor k. The addition of C6H5SO2Cl to the RTMS was shown to improve its chemical stability and the reversibility of the lithium electrode because of the rem oval of AI(2)Cl(7)(-) from the melt. Electrochemical reaction which occurre d at the LiCoO2 was studied and the carbon current collector was found to i nteract with the melt. Out of the various carbon materials studied, graphit e was found to be the best material. A LiAl/LiCoO2 battery using RTMS as th e electrolyte was assembled for battery test. Satisfactory results were obt ained in preliminary cycling, showing a cell voltage of 3.45 V with better than 90% coulombic efficiency and a discharging capacity of 112 mA h/g LiCo O2 at current density of 1 mA/cm(2). (C) 1999 Elsevier Science S.A. All rig hts reserved.