Oxygen-rich functionalized porous carbon by KMnO4 activation on pods of Prosopis juliflora for symmetric supercapacitors

The need for energy storage devices with low-cost electrode material is predominant in joining the race to meet the energy crisis. The present work aims to turn the invasive weed, Prosopis juliflora (PJF), to serve energy storage applications under the turning waste into wealth concept. The porous carbon was prepared from PJF at different temperatures (600, 700, and 800 °C) using KMnO4 as the activating agent. The obtained carbon offers oxygen-rich functional groups (36 %), a high specific surface area (1210.4 m2g−1), and a hierarchical porous carbon network. The synthesized carbon (PJF-700) facilitates abundant active sites, which offered a significant energy density of 13.13 Wh kg−1 at the power density of 450 W kg−1 with an operating voltage window of 1.8 V in 1 M Na2SO4 electrolyte @ 0.5 A g−1. The present work claims its novelty by reporting KMnO4 as the activating agent for PJF-derived biomass carbon resulting in oxygen-rich functional groups. The significance of synthesized carbon with distinct properties and promising electrochemical performances for supercapacitors is also explored. [Display omitted] •Prosopis juliflora, an invasive weed, is utilized to prepare porous carbon through a simple KMnO4 activation.•KMnO4 activation enables hierarchical porosity and oxygen-rich functional groups on activated carbon•The porous carbon pyrolyzed at 700°C offers a better electrochemical feature by improved surface area and favorable oxygen functional groups.•The symmetric supercapacitor built with PJF 700 produced a high energy density of 13.12 Wh kg-1 with 450 W Kg-1 of power density at 0. 5 A g-1.