Lithium Imide Electrolytes with Two-Oxygen-Atom-Containing Cycloalkane Solvents for 4 V Lithium Metal Rechargeable Batteries

Lithium bisperfluoroethylsulfonyl imide electrolytes with five‐, six‐, and seven‐membered cycloalkane solvents containing two oxygen atoms were characterized in order to develop the organic electrolytes for 4 V lithium metal rechargeable batteries. Among the examined electrolytes, ethylene carbonate (EC) and 1,3‐dioxane (DOX) mixed electrolyte (5:5) with as solute were found to be the most advantegeous, with high cycling efficiency (95.2%), good oxidation stability (>5 V), promising freezing point (−21°C), and high boiling point, (105%C) of DOX solvent. Furthermore, only a slight decline in discharge capacity was observed for a coin cell with this electrolyte. Lithium cycling efficiency was also found to increase with decreasing deposition current density. Especially at deposition/dissolution current density of , lithium cycling efficiency in (5:5) electrolyte achieved above 99%. Thermal tests disclosed that this mixed electrolyte showed good thermal stability even with the existence of lithium metal. © 2000 The Electrochemical Society. All rights reserved.