Experimental and theoretical studies on reduction mechanism of vinyl ethylene carbonate on graphite anode for lithium ion batteries

Vinyl ethylene carbonate (VEC) has been investigated as an electrolyte additive for use in lithium ion batteries. Even in small additive amounts (5 vol%) VEC was capable of preventing propylene carbonate (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. The passivating film resulting from the reductive decomposition of VEC on the graphite surface was comprehensively studied by FTIR and XPS as well as the density functional theory (DFT) calculations. (C) 2003 Elsevier B.V. All rights reserved.