A High Precision Study of the Effect of Vinylene Carbonate (VC) Additive in Li/Graphite Cells

Li/graphite coin cells containing different amounts of vinylene carbonate (VC) electrolyte additive were examined at different temperatures using the High Precision Charger at Dalhousie University. The charge endpoint capacities as well as the coulombic efficiency (CE) were compared to characterize the effect of the VC additive on the graphite electrode. The experiments show that VC improves the coulombic efficiency and reduces charge and discharge endpoint slippage at 50 and 60 degrees C. However, the addition of VC has little evident effect on the performance of the graphite electrode at 30 and 40 degrees C and also increases the irreversible capacity. By contrast, additions of VC have a marked impact on the coulombic efficiency and slippages of NMC positive electrodes, even at 30 degrees C. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.100112jes]