Impact of aqueous and organic electrolytes on the supercapacitive performance of activated carbon derived from pea skin

The present work reports the synthesis of porous activated carbons (AC) from pea skin; employing eco-friendly approach. The method involves chemical activation using suitable activating agent and the process of carbonization. The textural properties of synthesized product were studied using standard techniques of field emission scanning electron microscopy (FESEM), N₂ adsorption-desorption isotherms, Raman spectroscopy, X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). It was ascertained that the synthesized product is thermally stable and possess crystalline, porous carbon structure. For evaluating the electrochemical performance, AC based electrodes were tested in selected aqueous (1 M H₂SO₄, 1 M Na₂SO₄ and 6 M KOH) and organic (1 M LiClO₄ in Ethylene Carbonate/Propylene Carbonate (1:1 by volume)) electrolytes, using standard electrochemical techniques. The highest specific capacitance (192.7 F g⁻¹) was found in acidic aqueous medium, while high magnitudes of specific energy and power (17.86 Wh kg⁻¹ and 57.33 kW kg⁻¹ respectively), were observed for organic electrolyte. Also, AC based electrode exhibited good cyclic stability with ~85% capacitance retention for more than 5000 cycles. It is therefore expected, that the synthesized AC can be fruitfully used for supercapacitor applications.