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.