In–situ Molten Salt Template Strategy for Hierarchical 3D Porous Carbon from Palm Shells as Advanced Electrochemical Supercapacitors

Abstract

AbstractPorous carbon with a large specific surface area, high electrical conductivity and suitable pore sizes possesses large potential for electrochemical capacitance. Herein, a 3D hierarchical porous carbon materials (PC) were synthesized through in‐situ molten salt template route by using the renewable biomass waste palm shell as carbon source. The unique structures endow the synthetic PC excellent capacitive performance. As electrode for supercapacitors, the typical PC‐1‐700 sample showed excellent electrochemical capacitance (up to 326 F g−1 at 0.5 A g−1), cycling stability (99 % retention of its initial capacity) and perfect rate performance in 6 M KOH electrolyte. For security considerations, we have chosen the aqueous and the ionic liquid as the electrolyte in two‐electrode cells. For the two‐electrode symmetric supercapacitors, the maximum energy densities could be 10.4 Wh kg−1 in aqueous electrolytes, while it can deliver as high as 42.5 Wh kg−1 in ionic liquid electrolyte. The supercapacitor was capable of lighting a LED light bulb (3 V). The strategy holds great promise for preparing functional carbon materials from natural resources for fulfilling the demand in different areas.