Performance of electrochemical double layer capacitors using highly porous activated carbons prepared from beer lees

Beer lees precursor is chosen to prepare activated carbons having different physical and chemical properties. The beer lees-based activated carbons (BL-ACs) are characterized by N2 adsorption/desorption isotherms, adsorption energy distributions (AEDs), and X-ray photoelectric spectroscopy (XPS). Furthermore the electrochemical properties of the BL-ACs are assessed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and constant current charge/discharge method. The maximum specific capacitance (about 188 F/g at discharge current of l mA/cm2) is obtained in 0.1 M H2SO4 electrolyte solution, which is a relatively low electrolyte concentration. The overall results suggest that the BL-ACs are good candidates for EDLC electrode materials.