A facile production of microporous carbon spheres and their electrochemical performance in EDLC

In the absence of activation process, we prepared a series of carbon particles from saccharine, in which hydrothermal carbonization method was used. These particles have spherical or near-spherical morphology, controllable monodisperse particle size from the analyses of SEM. Raman and XRD results show that they are nongraphitizable. The BET surface area of these carbon spherules is around 400–500 m2 g−1 and the microporosity is about 84%, suggesting that the carbon particles are rich in micropores. The electrochemical behaviors were characterized by means of galvanostatic charging/discharging, cycle voltammetry and impedance spectroscopy. The results show that the specific capacitance of sucrose-based carbon spherule reached 164 F g−1 in 30% KOH electrolyte and a high volumetric capacitance over 170 F cm−3 was obtained. These carbon spherules could be promising materials for EDLC according to their facile preparation way, low cost and high packing density.

► The performance of the carbon spheres in EDLC was thoroughly studied. ► β-cyclodextrin is converted to carbon spheres by hydrothermal carbonization. ► The carbon spherule exhibits a high volumetric capacitance over 170 F cm−3.