Green synthesis of oxygen-enriched tobacco stem-derived porous carbon via pre-oxidation and self-activation for high-performance supercapacitors

The use of agricultural and forestry waste to produce functional materials is a significant approach to achieving carbon neutrality. Herein, a green and cost-effective pre-oxidation and self-activation approach has been adapted to produce porous carbon from discarded tobacco stems for supercapacitors. The analysis of tobacco stem structure evolution reveals that the pre-oxidation process facilitated the cross-linked structure of the tobacco stem and the formation of KCl crystals, endowing tobacco stem-derived porous carbon with abundant micropores and high oxygen content during self-activation. The impact of pre-oxidation and self-activation temperature on the carbon structural characteristics of tobacco stems is systematically investigated. The optimized porous carbon exhibited a specific capacitance of 320 F/g at 0.5 A/g with good rate capability. Besides, it delivered a high energy density of 10.68 Wh/kg in a symmetrical supercapacitor. This work provides a green route for preparing carbon electrode materials for high-performance supercapacitors using agricultural and forestry wastes.