Effect of heteroatoms on the electrochemical behaviours of quinone-incorporated carbon

Supercapacitor has a bright future in electrochemical energy storage devices due to its excellent power density and moderate energy density. Further modification of the activated carbon as electrode has been conducted in this study to achieve the higher electrochemical performance. The N-doped activated carbon was successfully synthesized by chemical activation of tea leaves with potassium carbonate, whereas S-doped activated carbon was prepared from hemp stems using sodium sulfite as the activating agent. Moreover, anthraquinone was introduced into the carbon by the sublimation method. The electrochemical performance of the electrode was investigated using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). It was found that the quinone-carbon electrode that fabricated from N-doped carbon, activated at 700 °C, gives the highest efficiency of AQ (97.26 %) as well as total capacity of 186.9 mAh g-1. The results implies that N-doped ACs and S-doped ACs play an important role enhance the charge capacity of by strengthening the π-π interaction between carbon and AQ, which leads to enhance the performance of the electrode.