Pyrolytic carbon black-derived porous carbon with spherical skeleton as recovered and enduring electrode material for supercapacitor

Abstract With the increasing quantity of waste tires, pyrolytic carbon black (CBp) as a kind of black pollutants has been limited in the application typically for rubber reinforcement due to its high ash content and small specific surface area, so it is quite necessary to develop new practical applications of CBp in the energy field to improve the utilization efficiency of carbon resources. Herein, CBp is proposed as a carbon precursor to prepare porous carbon for electrode materials via acid-base combined treatment and KOH activation process. The obtained activated CBp (A-CBp) has a higher degree of disorder, hierarchical pore structure and enhanced specific surface area, possessing a large quantity of electrolyte storage space, ions migration channels and active sites. Moreover, The sample of A-CBp displays 212.2 F g−1 at 1 A g−1 with 690.9 m2 g−1, superb cycling stability and excellent rate performance at high current densities, while CBp only shows a very low specific capacitance of 9.6 F g−1 at 1 A g−1 with 48.5 m2 g−1. In addition, the assembled symmetrical supercapacitor exhibits a superb energy density of 22.6 Wh kg−1 in 1 M Et4NBF4/AN organic electrolyte for practical application. This work demonstrates the structural changes of CBp in the activation process, which improves the added value of CBp as electrode material for supercapacitors, realizing the recycling of waste carbon resources in the energy storage field to reduce the consumption of fossil resources.