Highly microstructured porous carbon derived from vitex mombassae for high specific capacitance supercapacitors

Abstract

This study reports on producing highly porous carbon materials by carbonization and activation of biomass (Vitex mombassae) seed wastes. The pore textural properties and microstructures of the synthesized materials are controlled by adjusting the activation temperature from 600 to 800 °C. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, Raman and nitrogen adsorption and desorption are used to study the physical characteristics of the synthesized materials. The Brunauer–Emmet–Teller surface area, micropore surface area and pore volume increase with activation temperature. At activation temperature of 700 °C, the porous carbon acquires high specific area (2044 m2 g−1). The pore volume increases with increase in activation temperature 0.8–1.1 cm3 g−1 with high self-doping oxygen content. As a result of good physical characteristics, the prepared electrodes exhibit excellent performance with the specific capacitance up to 437 F g−1 at 5 mV s−1 in 6 M KOH electrolyte. The good capacitive behavior of the synthesized porous carbon depends on high surface area, micropore pore volume as well as moderate microstructures. The synthesized sample demonstrates high cyclic stability with capacitance retention of over 90% after 50,000 cycles.