Charge distribution of Lithium-doped graphane/graphene hybrid system: Role of nearly-free electronic states

•The transferred charges mainly distribute on the outmost graphane layer of system.•Graphane can screen the external charge and behave like classical plate capacitor.•Nearly-free electron states are dominant in band filling.

Charge distribution of Lithium-doped graphane/graphene hybrid system is performed by density functional theory. It is found that almost all of transferred charges reside on the graphane layer nearest to the lithium atom, and only a few of them stay in interior layers. It indicates that the graphane layer can screen the external charge offered by lithium atom and behave like classical plate capacitor. The underlying mechanism reveals that the predominance of nearly-free electron states in band filling play an important role in determining charge distribution.