A theoretical study of the electronic properties of intercalated graphite

Abstract

We present the results of electronic structure calculations for first and second stages of lithium intercalated graphite (LiC6 and LiC12). The various stages of Li intercalated graphite all have hexagonal symmetry, where different carbon layers are stacked with C-atoms directly on top of each other (AIAI...), as opposed to natural graphite where the C-layers are staggered (ABAB...). All our calculations have been performed within the framework of the extended tight binding method with Gaussian type basis sets. From the orbital and total densities of states, we conclude that Li-2s electrons are transferred into carbon π-bands. This results in shifting the Fermi level into the region of high density of states (compared with pure graphite) and, hence, to observed metallic behavior. The calculated density of states for LiC6 and LiC12 is 0.25 and 0.12/(eV C-atom), respectively. Recall that for pure graphite the value is nearly zero and for copper it is 0.29. We also found it instructive to obtain the electronic structure of LiC6 and LiC12 based on a rigid band model. © 1980.