Tetrachloroethylene as new film-forming additive to propylene carbonate-based electrolytes for lithium ion batteries with graphitic anode

Tetrachloroethylene (TCE) has been investigated as a new film-forming additive to propylene carbonate (PC)-based electrolytes for use in lithium ion batteries. Even in small additive amounts (3 vol.%) TCE was capable of preventing PC co-intercalation into graphite. The formation of a stable passivating film on the graphite surface is believed to be the reason for the improved cell performance. It is observed for the first time that the many particles with micrometer size were deposited on the graphite surface. EDX, IR and XPS results show that the film is probably composed of LiCl, ROCO2Li, Li2CO3, etc. In addition, the PC/TCE electrolyte has been proved to have a high oxidation stability (>4.5 V vs. Li/Li+) allowing the cycling of a LiMn2O4 cathode. TCE shows promising performance for use as an effective film-forming electrolyte additive in lithium ion batteries. (C) 2004 Elsevier B.V. All rights reserved.