Electrochemical Property Measurement of Monolithic Carbon Xerogel from Resorcinol and Formaldehyde for Supercapacitor Electrodes

Abstract

Monolithic carbon xerogel with porous structure was prepared via one-step, catalyst-free, hydrothermal reaction from resorcinol (R), formaldehyde (F) and distilled water (W). The reaction was carried out in a pressurized Teflon mold at 100 ℃ for 6 h with varied R/W ratios (45, 50, 55, 60) at a fixed R/F ratio of 0.5. The RF xerogels were subjected to pyrolysis at 500, 600, 700, or 800 ℃ for 4 h followed by cutting into a disk shape (~1 mm thickness) samples, and then immersed in 6 M KOH aqueous solution. After completed soaking, the carbon xerogels were activated at 600~800 ℃ for 1 h. These prepared carbon xerogels were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The textural properties (specific surface area, pore size distribution) of the obtained samples were also investigated by N2 adsorption-desorption measurements. Electrochemical property was also evaluated via cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The monolith carbon xerogels provided a specific capacitance of as high as ~320 F g-1 at a current density of 1 A g-1, which can be used as an electrode for supercapacitor without involving binder, filler and/or solvent.