Li-ion battery electrolyte formulated for low-temperature applications
- Covalent Associates, Inc., Woburn, MA (United States)
Low-temperature (<0 C) applications of Li-ion batteries have prompted the search for improved, high-conductivity electrolytes. Because the performance of the carbonaceous anode is highly sensitive to changes in electrolyte composition, the authors focused their efforts on this electrode. Electrolytes containing LiAsF{sub 6}, LiPF{sub 6}, LiN(SO{sub 2}CF{sub 3}){sub 2}[lithium bis(trifluoromethanesulfonyl)imide], or LiIm, and LiC(SO{sub 2}CF{sub 3}){sub 3} [lithium tris(trifluoromethanesulfonyl)methide], or LiMe, in methyl formate (MF)-ethylene carbonate (EC) solvent mixtures were tested in lithium-graphite half-cells. The graphite electrodes could be cycled at ambient temperature with high reversible capacity. The best supporting electrolyte was found to be LiAsF{sub 6}, and the presence of a high concentration of ethylene carbonate and up to 300 ppm H{sub 2}O in the solution considerably increased the reversible capacity upon cycling. The conductivity values of a binary solvent mixture of methyl formate and ethylene carbonate containing LiAsF{sub 6} or LiMe were measured between {minus}40 C and room temperature. Graphite electrodes cycled at {minus}2 C in these electrolytes obtained reasonable reversible capacity, approaching 50%.
- Sponsoring Organization:
- Office of Naval Research, Washington, DC (United States)
- OSTI ID:
- 483779
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 3 Vol. 144; ISSN 0013-4651; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
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