Constructing ultraporous activated hollow carbon nanospheres derived from rotten grapes for boosting energy density and lifespan supercapacitors

Food waste-derived porous carbons are attracting much attention as green, efficient, and affordable electrode materials for supercapacitors. Designing novel carbon nanostructures has the potential to boost electrochemical performance significantly. Herein, we report nitrogen-enriched hollow porous carbon derived from rotten grapes for providing affordable and efficient storage capabilities. Due to its ultrahigh specific surface area of 2756 m2 g  1 and excellent wettability characteristics, the activated hollow carbon nanosphere (AH-Csp) derived from the rotten grape precursor achieves the capacitance of 375 F g  1 at 1 A g  1 in a KOH-based electrolyte. The designed symmetric supercapacitor device (AH-Csp//AH-Csp) delivers a high energy density of 26.33 Wh kg  1 at a power density of 400 W kg  1 and exceptional cyclability with only 5.74% capacity fading after 12000 cycles. This strategy paves the way for developing efficient and economic electrode materials for robust, scalable, and affordable energy storage devices.