Despite the initial CV results, A-CuHHTP and B-CuHHTP exhibited similar specific capacitances, Cg, at low current densities (129 ± 2 and 127 ± 5 F g -1 , respectively) (Fig. ). This suggests that both A-CuHHTP and B-CuHHTP have pore structures which are freely accessible to organic electrolyte ions at long charging times. This result seemingly contradicts the N2 sorption isotherm data, which suggested a larger accessible surface area for A-CuHHTP. As reported previously, this suggests that BET areas are not always an accurate predictor of the electrolyte ion accessible surface area, and therefore the capacitance, of porous materials. In contrast, C-CuHHTP displayed a significantly lower specific capacitance of 36 ± 6 F g -1 at 0.05 A g -1 , supporting previous reports that strongly agglomerated microstructures have lower capacitive performance and energy storage compared to samples with weaker particle agglomeration. This is likely due to limited ionic diffusion through the spherical agglomerates, resulting in poor ion accessibility to the crystallites at the centre of the agglomerates.