The electrochemical properties of porous carbons used as supercapacitor electrodes are largely determined by the pore size and its distribution. Here, we report that high-mesopore-volume nanocarbons (HMC) produced by one-step sintering process considerably improve the capacitive behavior by providing the desired highly accessible surfaces. The symmetric supercapacitors based on the HMC materials show high gravimetric capacitances of similar to 180 and similar to 215 F g(-1) and also high volumetric capacitances in organic and ionic liquid electrolytes. High mesoporous volume ratio of HMC sample (similar to 76%) facilitates fast ionic transport while preserving good electronic conductivity and thus delivers both high energy and power density. This simple, cost-effective and scalable preparation technique and excellent capacitive behavior of HMC samples encourage their practical application. (C) 2015 Elsevier Ltd. All rights reserved.