Sustainable activated carbon derived from biomass of Borassus flabellifer: Unveiling their potential as electrode in supercapacitors for triazolium ionic liquid-based systems

Abstract

Biomass is the most plentiful renewable source of energy. Biomass has many uses, one of which is the production of activated carbon (AC), which is then utilised as an electrode in energy storage devices. The goal of this work is to synthesize a novel AC that is compatible with room temperature triazolium-based ionic liquids. The prepared AC was characterized by BET, SEM, XRD, and RAMAN techniques. The surface area, pore volume, and pore radius of the AC were 780 m²/g, 0.519 cc/g, and 1.33 nm, respectively. Additionally, novel symmetrically and asymmetrically substituted triazolium ionic liquids (IL) are synthesized and characterized. Cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge studies were used to examine the electrochemical performance of the device. The symmetrical IL provided an excellent specific capacitance of 62.29F/g at 2 mV/s, an energy density of 1.06 W h/kg, a power density of 229.5 W/kg, and maintained 76 % retention after 1500 cycles. For asymmetrically substituted IL, a reversible potential window of around 2 V was obtained along with a capacitance of 91.31F/g at 2 mV/s, an energy density of 2.8 W h/kg, a power density of 420 W/kg, and maintained 73.9 % of capacitance after 1500 cycles.