Biomass-derived graphitic-like hierarchical porous carbon for electrochemical supercapacitor application

High conductivity and applicable pore size are typically anticipated as key features for high-performance capacitive carbon electrodes in supercapacitor applications. However, these desired characteristics often conflict with each other, making incorporating both into a single carbon material challenging. Herein, graphitic-like hierarchical porous carbon (GHPC) was synthesized through a straightforward two-step pyrolysis process, utilizing pumpkin skin as the precursor without activating agents. We found that in contrast, to single pyrolysis under N2 atmosphere, further annealing under H2 gas effectively improves specific surface area and creates a graphitic-like hierarchical porous structure with mesopores, achieving an effective electrode potential for supercapacitors. GHPC's unique graphitic-like hierarchical porous structure contributes to excellent electrochemical performance achieving a specific capacitance of 274 Fg- 1 and exceptional rate capability of 67 % at 1 Ag- 1. Furthermore, GHPC showcased an outstanding cyclic stability of 95.7 % at current density of 2 Ag- 1 after 5000 cycles in 1 M KOH analyte, comparable to the state-of-the-art chemically activated biomass-derived carbon. These results emphasize the potential of biomass-derived graphitic-like hierarchical porous carbon as a promising electrode material for high-performance supercapacitors.