Effect of Electrode Thickness on Capacitive and Self-Discharge Performance of Carbon-Based Supercapacitor

Supercapacitor is an energy storage device that has electrodes, electrolyte, separator and current collector components. In this study, activated carbon electrode material with turbostratic structure having the interlayer spacing ( d 002 ) of 3.550 Å, and with porosity having the specific surface area ( S BET ) of 685 m 2 g -1 was used to prepare electrodes with the thickness of 0.1, 0.3 and 0.5 mm for symmetrical supercapacitor cells, respectively. Electrochemical tests show that the reduction in the electrodes thickness from the thickest electrodes to 0.1 mm causes the specifics capacitance, energy and power of the cells to increase by factors of 6, 5, and 3.5 times, respectively, to reach the values of 37 F kg -1 , 5 W h kg -1 , 114 W kg -1 . This test also shows that the length of time domain in which the activation-controlled mechanisms that dominantly drives the voltage decay during self-discharge and the corresponding voltage decay rate, which are longer and higher for the cell (0.1 mm), respectively. Furthermore, the self-discharge data show the present of the time region of dominant diffusion-controlled mechanism for the cell (0.5 mm) but show the absence of such region for the other cells.