Controlling activation parameters in phytagel-derived activated carbons for enhanced supercapacitor performance

Activated carbons, because of their high surface area and well-developed pore structure, are a very good electrode material for energy storage devices. The properties of activated carbons can be tuned by modifying certain factors such as activating agent, activation temperature, time, concentration of activating agent, etc. In the present work, the effect of activating agent concentration on the properties of activated carbon is systematically investigated by synthesizing a series of samples via chemical activation and carbonization of a biopolymer, phytagel, using zinc chloride (ZnCl 2 ) as the activating agent. Five different samples of activated carbons are prepared by using the phytagel to ZnCl 2 w/w ratio in 1:0, 1:1, 1:2, 1:3, and 1:4. The prepared activated carbons are characterized using different characterization tools such as XRD, Raman, BET, SEM, TEM, EDX, XPS, etc. To study the practical application, all the activated carbons are used to fabricate solid-state supercapacitors, which are further characterized using EIS, CV, and GCD in a two-electrode geometry. The activated carbon with phytagel to ZnCl 2 w/w ratio 1:3 shows the highest specific capacitance of 129 F g -1 at 0.5 A g -1 and an energy density of 17.9 Wh kg -1 at a power density of 974 W kg -1 .