Mesoporous-rich and oxygen-rich hierarchical porous carbon derived from Black Humic Acid for supercapacitor electrode

Constructing reasonable pore structures and elements doping are significant for applying porous carbon materials in supercapacitors. Black humic acid is widely distributed in soils, waters and sediments, which inherently contains oxygen functional groups. In this research, black humic acid is used as a carbon source, and H2O2 oxidation is synergistically applied with KOH activation to promote the formation of mesopores and enhance oxygen content to prepare the oxygen-rich and mesopore-rich hierarchical porous carbon material (HPCOA). HPCOA has a high oxygen content of 26.39 atom%, an abundant mesopore ratio of 87.00%, and a high specific surface area of 1727 m2·g-1. In a 6 M KOH electrolyte, the electrode material of HPCOA as a supercapacitor exhibits a specific capacitance of 226 F⋅g-1 at 0.2 A⋅g-1. The symmetric electrodes exhibit an energy density of 11.28 Wh⋅kg−1 with a power density of 60.00 W⋅kg−1 and the capacitor retention are 98.53% after 6000 cycles. The research proposes a new strategy from hierarchical porous carbon materials to regulate the mesoporous formation and oxygen doping, providing carbon electrode materials for supercapacitors with excellent performance.