With an expanded series of nanoporous carbons including those from our previous studies, it is observed that carbons with higher gravimetric capacitances generally have (i) larger ion adsorption capacities (Figure ) and (ii) Δδ values of smaller magnitude (Figure ). The correlation between the capacitance and the ion adsorption capacity was much less obvious in our previously studied commercial activated carbon series (Figure , grey points) , likely because they have similar pore volumes (mostly 0.8-0.9 cc g - 1