Hierarchical porous active carbon from fallen leaves by synergy of K2CO3 and their supercapacitor performance

Hierarchical porous active carbon materials (ACs) are prepared by activation treatment and the fallen leaves are used as the carbon source. The mixed activators K2CO3/KOH provide the possibility to obtain the hierarchical pore structures on ACs. The micro-, meso- and macropores can be observed by N2 adsorption-desorption isotherm and TEM. The capacitance of ACs is up to 242 F/g at 0.3 A g−1 in two-electrode system and with nearly no decrease after 2000 cycles.184