3D sponge-like nanoporous carbons via a facile synthesis for high-performance supercapacitors: direct carbonization of tartrate salt

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   μF   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   μF   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 .