Sorghum biomass-derived porous carbon electrodes for capacitive deionization and energy storage

Biomass-derived carbons are widely studied as cost-effective and high-performance energy storage materials due to their high specific surface area, abundance, and facile synthetic methods. Through widespread research, a number of strategies can be implemented to maximize specific capacitance and power. Among the different approaches to improve the energy storage performance of biomass-derived carbons, an increase of specific surface area and the introduction of heteroatom doping are usually effective strategies. As such, in this study, we utilize sorghum stem biomass to obtain porous carbonaceous forms, and subsequent KOH activation to increase the porosity and surface area. The resulting activated sorghum stem-derived porous carbon materials exhibit significantly higher specific capacitance compared to their pre-activated carbon. Capacitive deionization (CDI) that is used to deionize water is also studied to demonstrate the versatility of sorghum stem-derived porous carbon. A similar performance trend is observed for both supercapacitor and CDI for all carbon samples because both applications exploit the electrostatic double-layer capacitance behavior of carbon materials.