Preparation and Characterization of Physically Activated Carbon and Its Energetic Application for All-Solid-State Supercapacitors: A Case Study.

Biomass-derived activated carbons have gained significant attention as electrode materials for supercapacitors (SCs) due to their renewability, low-cost, and ready availability. In this work, we have derived physically activated carbon from date seed biomass as symmetric electrodes and PVA/KOH has been used as a gel polymer electrolyte for all-solid-state SCs. Initially, the date seed biomass was carbonized at 600 °C (C-600) and then it was used to obtain physically activated carbon through CO 2 activation at 850 °C (C-850). The SEM and TEM images of C-850 displayed its porous, flaky, and multilayer type morphologies. The fabricated electrodes from C-850 with PVA/KOH electrolytes showed the best electrochemical performances in SCs (Lu et al. Energy Environ. Sci. , 2014 , 7 , 2160) application. Cyclic voltammetry was performed from 5 to 100 mV s -1 , illustrating an electric double layer behavior. The C-850 electrode delivered a specific capacitance of 138.12 F g -1 at 5 mV s -1 , whereas it retained 16 F g -1 capacitance at 100 mV s -1 . Our assembled all-solid-state SCs exhibit an energy density of 9.6 Wh kg -1 with a power density of 87.86 W kg -1 . The internal and charge transfer resistances of the assembled SCs were 0.54 and 17.86 Ω, respectively. These innovative findings provide a universal and KOH-free activation process for the synthesis of physically activated carbon for all solid-state SCs applications.