Hierarchically porous carbon derived from tobacco waste by one-step molten salt carbonization for supercapacitor

High-performance carbon materials were prepared via a one-step molten salt carbonization of tobacco waste used as electrode materials for supercapacitors. Carbon material prepared by carbonization for 3 h in molten CaCl2 at 850 degrees C exhibits hierarchically porous structure and ideal capacitive behavior. In a three-electrode configuration with 1 mol L-1 H2SO4 aqueous solution, it delivers specific capacitance of 196.5 F g(-1) at 0.2 A g(-1), energy density of 27.2 Wh kg(-1) at 0.2 A g(-1), power density of 983.5 W kg(-1) at 2 A g(-1), and excellent cyclic stability with 94% capacitance retention after 5000 charge-discharge cycles at 1 A g(-1). Moreover, in a symmetrical two-electrode configuration with 6 mol L-1 KOH aqueous solution, it delivers specific capacitance of 111.1 F g(-1) at 0.2 A g(-1), energy density of 3.8 Wh kg(-1) at 0.2 A g(-1), and power density of 482.0 W kg(-1) at 2 A g(-1). The relationship between hierarchically porous structure and capacitive performance is also discussed.

Automated summary

High-performance carbon materials were prepared via one-step molten salt carbonization of tobacco waste, displaying excellent capacitive behavior in both acidic and alkaline electrolytes. The hierarchically porous structure of the carbon material contributes to its superior capacitive performance.