Palmyra palm flower biomass-derived activated porous carbon and its application as a supercapacitor electrode

Abstract

Due to its abundant availability, eco-friendliness, and high sustainability, biomass-derived acti­vat­ed carbon has captured more attention in recent years. In this study, activated carbon was derived from Palmyra palm flowers (PPF) using a conventional chemical activation process and carbo­nization at different ambient temperatures, viz. 700, 800, and 900 °C. The carbonized PPF was chemically activated using 1 wt.% potassium hydroxide to increase the microporosity and specific surface. The experimental data were analyzed using an X-ray diffractometer (XRD), scanning elec­tron microscopy (SEM), energy-dispersive X-ray spectrometer (EDX), Raman spectr­oscopy and Fourier transform infrared spectroscopy (FT-IR). The nitrogen adsorption/de­sorption isotherm curve for activated carbon synthesized at the activation temperature of 900 °C indicated type IV with a hysteresis loop associated with mesopores formation and a specific surface area of 950 m2g-1. The supercapacitor electrodes made with PPF-derived carbon were evaluated for their electrochemical performance by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge measurements. In the aqueous electrolyte (3 M KOH), electro­chemical experiments showed that PPF-900 electrode has a specific capacitance of 155 F g-1 at 1 A g-1 and significant cyclic stability (97.3 % capacitance retention over 5000 cycles at 10 A g-1), while energy and power densities were estimated as 15.1 Wh kg-1 and 100.6 W kg-1. This study suggests that biowaste products could be transformed into activated carbon materials to improve the performance of energy storage materials, and it adheres to the 'waste to treasure' principle.