Bonding character of lithium atoms adsorbed on a graphene layer

Abstract

This work uses first-principles calculations to investigate the aspects of the bonding character of lithium atoms adsorbed on a graphene layer. The presented results are in contradiction to other results that have recently appeared in the specialized literature, although they confirm some previous claims. In particular, a discussion of the characteristics of the bonding between lithium and carbon atoms and whether they interact via an sp2 or an sp3 hybridization is intended to clarify the problem. It is also found that the carbon–lithium bond is not purely covalent but instead presents a significant ionic character. The local geometry is governed by the π-acceptor character of lithium atoms which occupy reverse positions relative to the carbon atoms as compared to the positions of hydrogen in graphane.