Enhanced Electrochemical Performance of Porous Carbon Derived from Cornstalks for Supercapacitor Applications

Biomass is a reliable and sustainable source of energy and chemicals. It is important to find simple and green solutions to turn the large amount of available biomass into materials with high added value. Porous carbon with a unique microporous structure has been prepared from cornstalk waste by simple carbonization and activation processes, and used as an electrode material for supercapacitors. The obtained porous carbon with high specific surface area (408 m(2)/g) and appropriate pore size distribution (1 nm to 2 nm) provided multiple energy storage sites and ionic diffusion paths, effectively improving the electrochemical characteristics. In a symmetric supercapacitor system, the produced electrode exhibited high specific capacitance of 125 F/g and outstanding cycling stability with capacitance retention of 88% after 2000 cycles in aqueous electrolyte. Moreover, a high energy density of 15.3 Wh/kg and a specific capacitance of 62 F/g were achieved in organic electrolyte. This approach could provide a novel route for high-performance energy storage materials derived from biomass waste.