A range of in situ experimental techniques have been developed to characterise the charge storage mechanisms in supercapacitors. Nuclear magnetic resonance (NMR) spectroscopy, infra-red (IR) and Raman spectroscopies, small angle X-ray and neutron scattering (SAXS and SANS, respectively) and electrochemical quartz crystal microbalance (EQCM) techniques have all been used to investigate porous carbon-based EDLCs. Due to the limitations of each technique in terms of the probed time-and length-scales, as well as differing chemical selectivities, these techniques are best employed in combination. For example, NMR spectroscopy can provide specific and quantitative information on the cations, anions and solvent in supercapacitor electrolytes. Decoupling and quantifying contributions from different electrolyte components is more difficult in EQCM, SAXS and SANS, and is generally not possible with IR spectroscopy. However, NMR spectroscopy requires good NMR-active nuclei for study, and unambiguous quantification of charge storage mechanisms relies on good resolution of the resonances arising from in-pore species (in the electric double-layer) and free electrolyte species in the NMR spectrum. Both the thermodynamic and kinetic charging regimes can be probed with in situ experimental techniques. NMR spectroscopy has mainly been used to study thermodynamic charging mechanisms (i.e. under constant voltage equilibrium conditions) due to the relatively long times needed to obtain a single NMR spectrum and the slow charging times of the custom cells used for in situ measurements. In contrast, EQCM measurements are generally made continuously as the cell state-of-charge is varied, and these measurements have been used to provide insights on the kinetic regime during charging. In situ X-ray transmission measurements have also been used to study the kinetic charging regime, with different charging mechanisms observed depending on the charging rate. While the charging mechanisms of carbon-based EDLCs have been extensively probed, experimental work on MOF-based EDLCs is much more limited. Most prominently, He et al. employed in situ SANS to study the charging mechanism dynamics of Ni3(HITP)2 EDLCs with sodium triflate organic in dimethylformamide (DMF) electrolyte. It must be noted that the electrochemical performance of this system was not measured as part of this work. From fitting the changes in scattering intensity, He et al. concluded that the dominant mechanism was dependent on the electrode polarisation, with a charging mechanism intermediate between exchange and counter-ion adsorption suggested. The study reported that the MOF pores were ionophobic with this electrolyte (i.e. the ions are preferentially located outside the MOF pores). This was the first reported example of ionophobicity in MOF-based supercapacitors, and was interestingly in contrast to a computational study on the same MOF with an ionic liquid electrolyte, where the pores were found to be ionophillic. Theoretical studies of model slit pores suggest ionophobic pores give rise to improved power and energy performance. Given that this unusual ionophobic example has been identified in one of the first mechanistic studies of MOFs, this motivates further investigation of MOF EDLCs to understand how ionophobicity is achieved, and its influence on EDLC performance.