THEORETICAL STUDY OF LiC6

We have studied the relative stability of the [MATH] and [MATH] stackings of stage 1 lithium in graphite at zero temperature, focusing on the Li-C chemical bond in each case. We have determined the equilibrium atomic structure of LiC6 with a first-principles molecular dynamics technique, in particular for the Li atoms equilibrium positions, and the effect of Li-intercalation on the graphite planes. We found that the [MATH] stacking is favorable, although the energy difference turns out to be quite small. A very slight distortion of the graphite lattice gives rise to two different classes of hexagonal rings, depending on whether they are occupied by lithium atoms