We calculate the optimized geometry and the corresponding electronic s
tructure of Li ions doped in a small graphite cluster with dangling bo
nds or hydrogen terminations at the edge surrounding the cluster. The
calculations imply both covalent and ionic bonds of Li ions to carbon
atoms, which may be relevant to explaining the broad signal of the Li-
7 NMR Knight shift spectra. Li intercalation, in particular, is possib
le even at the hydrogen-terminated edges. Because of the finite size e
ffect of the cluster, the ionicity of intercalated Li ions has a large
distribution of values, ranging from positive values close to that in
graphite intercalation compounds to even slightly negative values, de
pending on the bonding geometry. We propose that the cluster edge surf
ace plays a special role in accommodating excess Li ions in the disord
ered graphite system.