We report the direct synthesis of 3D sponge-like nanoporous carbons via carbonization of tartrate salt, including potassium tartrate and sodium tartrate, in inert atmosphere without any activation. The carbonization temperature is a very important parameter that ensures formation of the desired carbon structures and enhances their electrochemical performance in supercapacitors. Given that alkali metal is present in the selected carbon precursor, high-temperature activation causes reaming of carbon-K-800-1 to achieve a high specific surface area of 1018 m(2) g (1), thereby rendering the material suitable for use as an electrode for supercapacitors. All of the aqueous measurements were performed in a three-electrode system with 6 M KOH as the electrolyte. Carbon-K-800-1 can deliver a high specific capacitance of 296 F g (1) (29.1 mu F cm (2)) at a constant charge-discharge current of 0.7 A g (1); this capacitance may be maintained at 213 F g (1) (20.9 mu F cm (2)) at 20 A g (1). A long cycle stability of 95.1% capacitance retention was observed after 5000 charge-discharge cycles at a current density of 3 A g (1). (C) 2015 Elsevier Ltd. All rights reserved.