  Ionic liquids (IL) are promising electrolytes for electrochemical
applications due to their remarkable stability and high charge density.
Molecular dynamics simulations are essential for better understanding the
complex phenomena occurring at the electrode-IL interface. In this work, we
have studied the interface between graphene and 1-ethyl-3-methyl-imidazolium
tetrafluoroborate IL, using density functional theory-based molecular dynamics
simulations at variable surface charge densities. We have disassembled the
electrical double layer potential drop into two main components: one involving
atomic charges and the other - dipoles. The latter component arises due to the
electronic polarisation of the surface and is related to concepts hotly debated
in the literature, such as the Thomas-Fermi screening length, effective surface
charge plane, and quantum capacitance.
