Journals
Laser Photochemistry Laboratory
Journals
Laser Photochemistry Laboratory
Abstract
This research has investigated the viability of valorizing Areca or Betel palm-shells into activated carbon, to be applied as an electrode active material in supercapacitors. The palm-shells are an agricultural waste from betel-nut production, an important economic crop in several regions around the world. The conversion process mainly involves pulverization, ZnCl 2-activation, and carbonization. The effect of carbonization temperatures – 500, 600, 700, and 800 °C, was studied on the properties of the activated carbon. Microstructural characterizations like BET, Raman, and XPS were carried out. All the activated samples are microporous, have a specific surface area > 1,000 m 2 g -1 , and possess an intensity ratio of D-to-G band close to 1. More than 80 % of the atomic concentration of the samples is carbon; the C 1s bonds include C=C or sp 2 , C–C or sp 3 , C–(O,N), C=O, and O–C=O or π- π*. The activated carbon synthesized at 700 °C shows the most favorable properties for being used as the electrode in supercapacitors. Its electrochemical properties, evaluated by galvanostatic charge-discharge and cyclic voltammetry deliver the maximum specific capacitances of 144.48 F·g -1 at 1 A·g -1 and 169.21 F·g -1 20 mV·s -1 , respectively. The supercapacitors do perform stably at long-term cycling with the capacitance retention (> 98%) and the coulombic efficiency at almost 100 % over 50,000 cycles. The betel -palm-shell carbon has a very comparable capacitive performance to other biomass-derived carbons with the respective maximum energy and powder densities of 7.63 Wh·kg -1 and 5,849.93 W·kg -1 .