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 °C, 600 °C, and 700 °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 m2 g−1 to 1218 m2 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.