Flexible solid-state supercapacitors based on biowaste-derived activated carbon and nanomaterials for enhanced performance

Supercapacitors are energy storage devices with long cycle life that can harvest and deliver high power. This makes them attractive for a broad range of applications including flexible and lightweight wearable consumer electronics. In this work, we fabricate flexible solid-state supercapacitors with improved capacitance and cycle life. We synthesize activated carbon (AC) from cabbage leaves as a low cost, biowaste-derived active electrode material. To improve mechanical flexibility and conductivity, we incorporate reduced graphene oxide sheets (RGO) and carbon quantum dots (CQDs) into the electrodes. We show that at the optimum AC/RGO/CQD composition, the capacitance of the solid-state supercapacitor is maximized while its scan rate dependence and bending stability are simultaneously improved. We envision that this approach offers significant potential for delivering efficient energy storage devices for consumer electronics.