Hierarchical Nanoporous C/C Composite from Humic Fulvic Acid and Sulfonated Pitch for High-Energy-Density EDLC Electrodes

Graphical A hierarchical nanoporous C/C composite with high specific surface area was synthesized from sulfonated pitch and fulvic acid for high-energy-density EDLCs. It exhibits a highly continuous 3D carbonaceous network. By fully exploiting the synergistic effect between high e -conductivity and high specific surface area, it shows excellent electrochemical stability in EMIMBF 4 ionic liquid electrolyte. The maximum energy density can be as high as 55.4 Wh kg −1 , largely better than commercial activated carbon. As a new type of energy storage device, electric double layer capacitors (EDLCs) possess fast charge/discharge speed and good cycling stability. However, the low energy density and high production cost of EDLC electrodes are still big challenges. Herein, a hierarchical nanoporous C/C composite is synthesized by chemical recombination and subsequent activation strategy from low-cost carbon resources, namely renewable humic fulvic acid (FA) and industrial sulfonated pitch (SP). Profiting from the abundant polycyclic aromatic hydrocarbons in SP and plentiful oxygen-containing groups in FA, the resultant nanoporous C/C composite has both high e -conductivity and high specific surface area (SSA). Thus, this porous C/C composite can be directly fabricated as EDLC electrode without any conductive agent. By fully exploiting the synergistic effect between high e -conductivity and high SSA, it shows excellent electrochemical stability in EMIMBF 4 ionic liquid electrolyte. Furthermore, it possesses a higher specific gravimetric capacitance (117 F g −1 ) than that of pure FA-based porous carbon (92.5 F g −1 ) at a current density of 1 A g −1 . More importantly, the maximum energy density can be as high as 55.4 Wh kg −1 , largely better than commercial activated carbon.