Waste tire-derived porous nitrogen-doped carbon black as an electrode material for supercapacitors

Abstract

Given that the disposal of waste tires has become a significant environmental hazard and economic challenge worldwide, establishing practical treatment processes and profitable applications for carbon black derived from waste tires are critical for boosting industrial pyrolysis of waste tires. In this work, nitrogen-functionalized waste tire-derived carbon black (WTCB) is successfully coactivated by melamine (M) and alkali metal-based activation agents, including C4H6K2O7-M, KHCO3-M, and KOH-M. The resultant porous carbon black exhibits excellent electrochemical performance due to the synergistic effect of nitrogen-doping and active-potassium-atom-induced pore creation. The proposed activation process serves to tune multiple physical properties of WTCB, such as the specific surface area, pore structure, wettability, and conductivity, all of which largely increase the electrochemical performance. C4H6K2O7-M, with a specific surface area of 247.5 m2/g and nitrogen doping of pyrrolic-N and pyridinic-N species, reaches the highest electrochemical capacitance. The activated WTCBs not only have porous features resembling activated carbon but exhibit comparable conductivity to commercial carbon black, emerging as a potentially viable alternative feedstock for carbon electrodes used in energy-related applications. Moreover, the proposed regeneration methods can be directly adopted in existing industrial pyrolysis plants, providing a feasible and greener implementation strategy for the industrial processing of waste tires.