EDLCs during charging, especially for systems with porous carbon electrodes. These studies have elucidated the charging mechanisms of EDLCs for both carbon nanotube electrodes with idealized model architectures, and realistic porous carbon electrodes, which are challenging to construct. The electrochemical environment was modelled based on the constant potential method, which applies an electric field in the simulation cell and describes the polarisation of the electrode charges as a point charge distribution. Similar MD simulations have been employed to study the charging mechanism of MOFs with ionic liquids, focusing on the EDLC response. This study elucidated the electrochemical interface of 2D MOFs and included both EDL structures and diffusion models, therefore giving information on both thermodynamics and kinetic phenomena. However, simple classical force fields cannot describe polarisation phenomena of the electrode, due to the absence of a realistic charge density distribution. In contrast to porous carbon electrodes, this becomes important for MOFs because of their heterogeneous electronic structures which arise from the distinct chemical building blocks. An alternative theoretical approach is to describe the electrode charge density at a quantum mechanical level. Recently, we studied the electrochemical interface of the Cu3HHTP2 MOF with a multiscale quantummechanics/molecular-mechanics (QM/MM) methodology, based on recent methodological developments on other electrochemical systems. The polarisation phenomena of the electrode were more accurately revealed by describing the MOFs at the QM level. For the studied range of charge densities, it was found that the electronic charges (or holes) are localised solely on the organic ligand, and not the metal ion nodes. The counter-ion insertion mechanism for negatively polarised electrodes and co-ion removal mechanism for positively polarised electrodes were shown to produce higher capacitances, respectively. Thus, these studies have begun to answer an open question in the field: "How does the charging mechanism affect the performance of a supercapacitor?". Using a quantum-mechanical description to study the charging mechanism of MOFbased supercapacitors becomes even more important when considering pseudo-capacitance.