Xm. Wang et al., Lithium imide electrolytes with two-oxygen-atom-containing cycloalkane solvents for 4 V lithium metal rechargeable batteries, J ELCHEM SO, 147(7), 2000, pp. 2421-2426
Lithium bisperfluoroethylsulfonyl imide (LiN(SO2C2F5)(2)) 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
1 mol/dm(3) LiN(SO2C2F5)(2) as solute were found to be the most advantageou
s, with high cycling efficiency (95.2%), good oxidation stability (>5 V), p
romising freezing point (- 21 degrees C), and high boiling point (105 degre
es C) of DOX solvent. Furthermore, only a slight decline in discharge capac
ity was observed for a Li/LiMn2O4 coin cell with this electrolyte. Lithium
cycling efficiency was also found to increase with decreasing deposition cu
rrent density. Especially at deposition/dissolution current density of 0.3/
0.6 mA/cm(2), lithium cycling efficiency in 1 mol/dm(3) LiN(SO2C2F5)(2)/EC
+ DOX (5:5) electrolyte achieved above 99%. Thermal tests disclosed that th
is mixed electrolyte showed good thermal stability even with the existence
of lithium metal. (C) 2000 The Electrochemical Society. S0013-4651 (99)08-0
90-8. All rights reserved.