Co-carbonization of bitumen asphaltenes and recycled cellulose acetate to fabricate hierarchical porous carbon with superior supercapacitor performance

Discarded cigarette butts constitute a significant source of solid waste, contributing to environmental pollution due to the non-biodegradable nature of cellulose acetate and the presence of toxic chemical residues. This study investigates, for the first time, the co-carbonization of bitumen asphaltenes with varying proportions of recycled cellulose acetate from cigarette butts at a constant temperature of 800 degrees C for 1 h. The effects of recycled cellulose acetate on the carbonization behavior of bitumen asphaltenes were analyzed in terms of surface morphology, pore structure, and electrochemical performance using techniques such as scanning electron microscopy, X-ray photoelectron spectroscopy, and supercapacitor testing. The resulting carbon materials exhibited a high specific surface area of 3613 m2 g-1, with well-defined hierarchical pores. In a three-electrode system, the porous carbon showed a high specific capacitance of 343.9 F g- 1 at 0.5 A g-1. When assembled into a symmetric supercapacitor, it achieved an energy density of 5.11 Wh kg- 1 at 8361.8 W kg- 1 power density. The carbon precursor with 33 wt % content of recycled cellulose acetate delivered the best electrochemical performance, benefiting from its abundant micropores and an optimal mesopore content. The high vaporization rate of recycled cellulose acetate can facilitate the pyrolysis and activation of bitumen asphaltenes during co-carbonization, promoting effective micropore and mesopore formation. The results suggest that the combination of bitumen asphaltenes and recycled cellulose acetate is a promising precursor for high-performance supercapacitors, offering a sustainable solution for both cigarette waste management and the value-added utilization of bitumen.