Activating agent-driven hierarchical nano-porous structure in mustard oil-derived carbon soot for supercapacitive...

In the present paper, activated nano-carbon soot is derived from atmospheric flame combustion of thymol-mustard oil followed by activation with potassium hydroxide (KOH) to produce micro- and mesoporous interiors. Different forms of activated nano-carbon soot are produced by using different weight percentage ratios 1:1, 1:3, and 1:5 of precursor carbon soot (CS) to KOH and named CS11, CS13, and CS15, respectively. An increase in specific surface area and average pore volume is observed with an increase in the amount of KOH with the hierarchical network having balanced micropores as well as mesopores in CS15. The electrochemical performance of prepared activated nano-carbon soot is further investigated by the fabrication of a symmetric electric double-layer solid-state supercapacitor (SC) device utilizing a 6 M KOH electrolyte. The CS15-based device displays the highest specific capacitance (C_sp) of 226.20 F/g at a current density of 0.5 A/g with energy density (E_d) 31.42 Wh/kg at a power density (P_d) of 250 W/kg. The C_sp, E_d, and P_d are found to be higher than activated nano-carbon soot reported in the literature. Further, three-coin cells are fabricated using CS15 which are tested in series combination with yellow light emitting diode (LED) and are found to be able to glow LED for ~ 5 min 25 s.