Dependence of capacitive properties of an EDLC on exfoliation time of graphite electrodes

The scientific focus has been directed through the production and application of “wonder material-graphene” after its discovery in 2004. But the mass production cost has become a huge disadvantage towards commercializing graphene-based manufactures. As alternative low-cost material, exfoliated graphite (EG) has emerged to be a novel nanostructured carbon material with a potential for electrochemical energy storage device applications owed to its unique characteristics similar to graphene. In this study a series of EG samples were prepared by a surfactant-mediated liquid-phase exfoliation method by changing the exfoliation time. Electrochemical double-layer capacitors (EDLCs) were fabricated using different EG samples as an electrode material and a gel polymer electrolyte (GPE). They were characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge discharge (GCD) techniques. EDLC having EG electrodes of 10 h exfoliation time showed the highest results with single-electrode specific capacitance ( C sc ) of 4.12 F g −1 , single-electrode specific discharge capacitance ( C sd ) of 1.10 F g −1 , and relaxation time of 0.22 s from CV, GCD, and EIS, respectively.