Enhancement performance of carbon electrode for supercapacitors by quinone derivatives loading via solvent-free method

Activated carbon (AC) from coconut shell, surface area of 764 m(2) g(-1), was functionalized with various quinone derivatives (anthraquinone (AQ), 9,10-phenanthrenequinone (PQ) or tetrachlorohydroquinone (TCHQ)) via a sublimation method for supercapacitor application. The properties of modified activated carbons were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption. The results showed a supercapacitor containing AC modified with 16 wt% AQ achieved higher specific capacitance than other quinone derivatives. AQ/AC performed specific capacitance about 485 F g(-1) at a current density of 1.0 A g(-1), resistance of 2.25 Omega and specific capacitance loss of 1.2% after 1000 charge-discharge cycles. The experimental data is in good agreement with the computational results of quinone adsorption on graphene surface; the lowest interaction energy (IE) of -28.0 kcal mol(-1) was obtained for AQ loading model. The modified AC successfully prepared by a solvent-free method which could be further developed as low-cost and environmentally friendly electrode materials for high-performance supercapacitors.