Porous carbon nanospheres with high EDLC capacitance

Abstract

This paper reports on the fabrication and electrochemical properties of porous carbon nanospheres, which have been prepared by the hydrothermal carbonization of natural glucose and subsequent activation of potassium hydroxide (KOH). Porous nanospheres with high bulk porosity and partial graphitization are obtained by the optimization of mass ratio (KOH: hydrochar). The optimal of specific surface area reaches 1563 m2/g with an average diameter of 3.64 nm. The maximum of specific capacitance of the activated carbon nanospheres is 207 F/g at a current density of 0.5 A/g, high rate capability (181 F/g at a current density of 10 A/g) and cycling stability (capacitance retention of nearly 96.7% over 1000 cycles). The high-conductive porous carbon nanosphere material with low microporosity and blind porosity might be a potential material for electrochemical double-layer capacitors (EDLCs).