Bead Mill for Supercapacitor Electrode Material: Why More Grinding Can Mean Less Capacitance. Supercapacitor (EDLC) electrodes rely on activated carbon's internal micro- and mesoporosity — its surface area — to store electrical charge, not just its particle size. Reducing particle size generally improves capacitance up to a point, but research has shown the relationship is non-monotonic: beyond a certain milling time, smaller particle sizes actually correspond to decreased