Having found that more disordered carbons have higher capacitances, we considered the question of why this is the case. To explore the impact of disorder on the charge storage mechanism, charged supercapacitor electrodes were studied with ex situ MAS NMR experiments on two selected carbons with contrasting levels of disorder, namely PW-400 (ordered carbon) and SC-1800 (disordered carbon). Magic angle spinning was required to resolve the in-pore peaks due to the small Dd value 200 for SC-1800, which precluded in situ measurements. To avoid solvent evaporation during cell disassembly and rotor packing, we employed a 0.5 M PEt4BF4 in propylene carbonate (PC) electrolyte, and then used 19 The ex situ NMR measurements report on the number of in-pore cations and anions at different charging voltages (Fig. , fig. ), as well as the excess ionic charge (Fig. ). For both of the 215 studied carbons, the anion uptake increases while the cation uptake decreases with increasing applied cell voltage for the positively charged electrodes, and vice versa for the negative electrodes (Fig. ). This suggests that both carbons store charge through an ion exchange mechanism, wherein counter ions are adsorbed and co-ions are expelled from the pores for both positive and negative charging . Importantly, the more disordered carbon (SC-1800) shows a greater capacity 220 to store ions at a given voltage than the more ordered carbon (PW-400) (Fig. ).