Improving the Electrochemical Performances of Supercapacitors through Modification of the Particle Size Distribution of the Carbon Electrode

Abstract

The effect of a synergetic mixture of large and small activated carbon composite particles on the performance of organic electrolyte-based EDLCs was examined in this work. Different surface areas, pore volumes, particle size distributions, and concentrations of surface functional groups were observed in bi-modal particle sizes of activated carbon composites. Using galvanostatic cycling, the cell capacitance of an activated carbon composite rose with an increase in the fraction of big particles (C8) over a wide range of rates. Due to their moderate specific surface areas, a relatively low fraction of smaller particle size, low concentration of oxygen functional groups, low contact resistance, and high ionic conductivity, the 0.25C4+0.75C8 carbon electrode composite has a high specific capacitance, high retention of high rate discharge, and long cycle life when compared to other composites and single carbon electrodes (C4, C8, and C12). The leakage current and gas evolution may be suppressed to an operating voltage of 3.0 V with an appropriate fraction of large and small particle composition on the carbon electrode, boosting the carbon cells’ reliability and stability.