Effective cost and high-performance supercapacitor electrodes from Syzygium oleana leave biomass wastes

Abstract

Effective cost and high-performance supercapacitor electrodes were prepared using Syzygium oleana leave biomass wastes. Simple one-stage integrated pyrolysis is adopted to get the porous activated carbon monolith without the addition of synthetic materials. The carbon samples were chemically activated by using sodium hydroxide. Four different carbonization temperature of 550 °C, 600 °C, 650 °C, and 700 °C have been evaluated and compared for their electrochemical behavior in supercapacitor cells. The physical characteristics were obtained using dimensions reduction and an X-ray diffraction method. The electrochemical properties of the porous activated carbon monolith were studied using cyclic voltammetry technique. Furthermore, two different aqueous electrolytes were selected to improve the electrochemical behavior of the electrode such as 1 M H2SO4 and 6 M KOH with low scanning rate of 1 mV s-1. The capacitive of symmetric supercapacitor showed high specific capacitance of 153 F g-1. Moreover, the maximum specific energy and specific power were found as high as 21.25 Wh kg-1 and 76.57 kW kg-1 at the voltage window of 0-1.0V. The simple and economically friendly method demonstrated to obtained porous activated carbon monolith derived from Syzygium oleana leaves waste makes them excellent candidates for future electrode materials of energy storage technologies.