A new perspective on the formation and structure of the solid electrolyte interface at the graphite anode of Li-ion cells

A new model describing the interactions between the graphite anode in Li-io n batteries and the liquid electrolyte reduction products [the solid electr olyte interface (SEI)] is presented. According to this model, certain solve nts and additives produce efficient passive films which mimic a double-laye r capacitor, wherein local, fixed positive charges in the SEI serve to coun teract the negatively charged graphite anode. The model also suggests that internal passive layer interactions are of a multilayered capacitor type. P reviously published experimental data in support of this model is presented . (C) 1999 The Electrochemical Society. S1099-0062(98)07-051-5. All rights reserved.