Hou et al. reported the popcorn-derived porous carbon flakes (PCFs) from maize biomass through the "puffing effect" by 2 minutes microwave irradiation at 900 W [935]. The PCFs were mixed with KOH, and activated using 750, 800, 850, and 900 ˚C, and the obtained samples were labelled as PCF-X, (X means activation temperature). The SBET of PCFs were increased with increasing temperature, and the maximum value of 3301 m 2 g -1 was recorded for PCF-900 sample. The XPS analysis showed the decreasing content of nitrogen, and oxygen with increasing activation temperature, while the carbon content was enhanced. For PCF-900, O, N, and S contents were 6.41, 1.08, and 0.34 wt%, and the carbon content for PCF-850, and PCF-900 were found to be 90.56 wt%, and 92.51 wt%, respectively, which was closer the commercially available YP-17D . The supercapacitor performances of the PCF-X were analysed in 6 M KOH aqueous electrolyte. PCF-900 electrode showed the highest specific capacitance of 348 F g -1 at 0.2 A g -1 , while the commercial carbon material YP-17D showed 158 F g -1 . The Ragone plot of PCF-900 electrode in ionic liquid delivered the specific energy density of about 103 Wh Kg -1 (53 W h L -1 ) at 0.5 A g -1 , and maintained a capacitance retention of 88 % after 5000 cycles at 5 A g -1 . The observed high supercapacitor performances are attributed to the high SBET that provided plenty of active sites, and interconnected layered flakelike structure could reduce the ion diffusion distance in the materials. Additionally, the heteroatoms could boost-up the wettability, and pseudocapacitance of carbon-based materials.