Effect of different activating agents on carbon derived from <i>Tinospora cordifolia</i> for EDLC application

Abstract The effect of two activating agents namely phosphoric acid (H 3 PO 4 ) and iron (III) chloride (FeCl 3 ) is investigated, in activation of carbon obtained from Tinospora cordifolia . The structural and morphological properties of the synthesized activated carbons were investigated using X-ray diffraction, scanning electron microscopy, Raman spectroscopy, and Brunauer–Emmett–Teller analysis. A notable yield of ∼60 % of the activated carbons was obtained using a simple and cost-effective approach of chemical activation followed by the thermal activation method. The electrochemical properties of the activated carbons were studied for electric double-layer capacitor application. The electrochemical impedance spectroscopy, galvanostatic charge–discharge and cyclic voltammetry studies revealed superior charge transfer properties of the carbon activated with H 3 PO 4 . The capacitor comprising carbon activated with H 3 PO 4 electrodes shows higher specific capacity of 58 F g −1 at 1 A g −1 than that of carbon activated with FeCl 3 (37.5 F g −1 ). The optimized capacitor delivers superior power density and energy density of 2 kW kg −1 and 28.33 W h kg −1 , respectively.