Conversion Syzygium oleana leaves biomass waste to porous activated carbon nanosheet for boosting supercapacitor performances

The porous activated carbon nanosheet derived from Syzygium oleana leaves biomass was prepared by one-stage integrated pyrolysis through both carbonization and physical activation for supercapacitor electrode as energy storage application. Carbonization was performed in three different temperatures, including 500 degrees C, 600 degrees C, and 700 degrees C. The 1 M potassium hydroxide was selected to produce activated carbon progressively. Importantly, the surface morphology and the samples were characterized by Scanning electron microscopy at a voltage of 15 kV and nitrogen adsorption/desorption at a temperature of 77 K. The results showed a like-flower nanosheets structure decorated by nanofiber increases the surface area of activated carbon from 216 m(2) g(-1) to 1218 m(2) g(-1) with tuneable well confirmed mesopores sizes. Degree of crystallinity and chemical composition also were characterized by using X-ray diffraction and Energy dispersive spectroscopy. Furthermore, electrochemical measurements had the best performances with a high specific capacitance of 188 F g(-1) at two-electrode system with a scan rate of 1 mV s(-1). (C) 2020 The Author(s). Published by Elsevier B.V.