Activated carbon from wasp hive for aqueous electrolyte supercapacitor application

In this work, a honeycomb-like hierarchical porous activated carbon derived from a sustainable wasp hive was produced by single-step chemical activation with potassium carbonate (K2CO3) as an activating agent at 800 degrees C for 1 h. The activated carbon was tested as a supercapacitor electrode for energy storage. The chemical activation with K2CO3 tailored the topography and surface properties to realize an amorphous macro-meso-microporous activated carbon material with a specific surface area of 765 m2/g and an average pore diameter of 2.4 nm. The highest specific capacitance (225 F/g) in 3-electrode cells was obtained in an acid electrolyte, whereas the neutral and alkaline electrolytes have lower specific capacitance. The wasp hive activated carbon electrode presented specific energy of 5.33 Wh/kg at 0.25 A/g, which exceeds the specific energy of a commercial activated carbon at the same conditions. About 100% coulombic efficiency was achieved with capacitance retention of 83.6% after 5000 charge/discharge cycles.