Electrochemical characteristics of lithiated graphite (LiC6) in PC based electrolytes

The influence of the surface film formed on the graphite surface in ethylen e carbonate (EC) on the lithium intercalation reaction into graphite in oth er electrolyte solutions including propylene carbonate (PC) was investigate d. A graphite sample could be charged and discharged in PC + DME, while no lithium intercalation occurred in either PC + DMC or in PC + DEC. However, the lithiated graphite (LiC6) obtained from a charge in EC with 1 mol dm(3) LiPF6 exhibited a reversible intercalation reaction with a large discharge capacity (370 mAh g(-1)) and a good cycle performance even in PC + DMC. Th is result suggests that nature of the surface film formed in EC is a domina nt factor in the reactivity of graphite with lithium ions in PC + DM, In PC + DME, the reversible capacity was smaller in both cases of the as-manufac tured graphite and the LiC6 obtained in EC. An XRD analysis indicated that the reduction in the crystalline size along the c-axis during the initial l ithium intercalation is responsible for the smaller capacity. (C) 2001 Else vier Science B.V. All rights reserved.