Electrochemical Property of Activated Carbon Monolith from Potato for Supercapacitor Electrode

Abstract

Electrochemical property of activated carbon monolith from potato was studied for possible application in supercapactor electrode. First, potato powder was purchased and used to prepare column shape samples via pressing. Then, they were subjected to two-step pyrolysis to avoid cracking, such as the 1st step at 300 °C at 0.5 °C/min heating rate and the 2nd pyrolysis at 400, 500 or 600 °C under N2 flow in a tube furnace. Next, the samples were cut into 1 mm thickness and then grinded into 0.5 mm, followed by immersing in 6M KOH solution and then the activation at 700 °C under N2 flow. Finally, the electrochemical properties of activated carbon monoliths were evaluated with a three-electrode system by cyclic voltammetry, galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). In addition, two-electrode system was also studied with the samples having highest specific capacitances, being from 400 °C pyrolysis. The samples were characterized by Raman, XRD, XPS and SEM, and specific surface area was also measured. Specific capacitance of 382 F/g was obtained from 400 °C pyrolysis, followed by 321 and 253 F/g from 500 and 600 pyrolysis, respectively.