Hydroquinone-modified Mesoporous Carbon Nanospheres with Excellent Capacitive Performance

Pure carbon materials store energy mainly by the electric double-layer mechanism, resulting in their low specific capacitance. However, pseudocapacitive materials can store energy through faradaic reactions, leading to drastically improved specific capacitance. Herein, mesoporous carbon nanospheres with 3D ordered pore symmetry were synthesized by soft template method. Then, the hydroquinone (HQ) was used to modify mesoporous carbon nanospheres by hydrothermal method. As demonstrated by cyclic voltammetry and galvanostatic charge-discharge tests, HQ modified carbon nanospheres show both electric double layer capacitance and pseudocapacitance. Carbon nanospheres with 10wt% HQ loading possess the highest specific capacitance of 285 F/g at the current density of 0.5 A/g and 212 F/g at 10 A/g, exhibiting excellent rate performance. This should be ascribed to the HQ molecules adsorbed on carbonaceous mesopore surface by interactions, which not only provide extra pseudocapacitance, but also improve the rate performance of carbons in aqueous electrolyte.