An unusual low-surface-area nitrogen doped carbon for ultrahigh gravimetric and volumetric capacitances

The popular pursuit of a high interior surface area, although leading to increasing capacitance records for carbon-based supercapacitor electrode materials, also produces low volumetric capacitances. We herein reported a porous nitrogen doped carbon material with a relatively low specific surface area of 403 m 2 g −1 and a total pore volume of only 0.29 cm 3 g −1 , exhibiting a very high gravimetric capacitance of 400 F g −1 and a volumetric capacitance of 507 F cm −3 in a three-electrode system. Simultaneously, the energy density reaches 26.1 W h kg −1 at a power density of 200 W kg −1 , and maintains 7.44 W h kg −1 at 5000 W kg −1 , in a symmetric two-electrode test conducted in 6 M KOH solution. The result implies a maximized utilization of the interior surface and the significant capacitance contribution resulted from each unit surface, for which a systematic investigation on the critical structural features has been given. An unusual low-surface-area N-doped carbon with nice performances of 400 F g −1 and 507 F cm −3 , for gravimetric and volumetric capacitances respectively, has been extensively investigated to reveal the structural features.