The role of defects and dimensionality in influencing the charge, capacitance, and energy storage of graphene and 2D materials

Abstract

The inevitable presence of defects in graphene and other two-dimensional (2D) materials influences the charge density and distribution along with the concomitant measured capacitance and the related energy density. We review, in this paper, the various manifestations of the capacitance including both the classical electrostatic (e.g. associated with double layer, space charge, chemical capacitances) and the quantum forms, as well as a few methodologies to tune the respective capacitances. The role of a proper determination of the surface area of 2D materials, considering the presence of defects, in determining the capacitance and the magnitude of the energy storage is also considered.