The changing structure by component: Biomass-based porous carbon for high-performance supercapacitors.

In this work, a simple and efficient method is introduced to prepare biomass-based porous carbon with excellent performance by changing the content of component (e.g., cellulose, hemicellulose, lignin, and extractives) of the raw materials. When the content of the components change, the corresponding carbon skeleton will be separated, resulting in a structure that is conducive to activation conditions. Using bagasse with fiber tubular structure as carbon precursor, the synthetic hierarchical porous carbon (BHPC-4) possesses a high specific surface area (SSA) of 3135 m2 g-1 more than the control sample (2484 m2 g-1). Benefitting from the improvement of the structure, the BHPC-4 electrode exhibits an appealing capacitance of 410.5F g-1 at 0.5 A g-1 and long-term cycling stability of 100% capacitance retention after 10,000 cycles in the 6.0 M KOH system. Furthermore, a delightful energy density of 25.6 Wh kg-1 at a 226 W kg-1 can be achieved in 1.8 V Na2SO4 aqueous symmetrical supercapacitors. This method has universal significance in preparing high-porosity and high-performance biomass-based carbon materials for various energy storage/conversion.