Activated Carbon Tailored by Potassium Hydroxide from Waste Tires as a Supercapacitor Electrode

Hard-carbon materials are considered as the most promising anodes in various energy storage system applications including lithium, sodium, potassium ion batteries and supercapacitors. Given the huge bulk of the waste tires produced by the rapid development of automobile industry, recycling waste tires to generate value-added products is crucially important for the development of a more sustainable world. In this work, we demonstrate how waste tire-derived pyrolytic char can be transformed into activated carbon for supercapacitor electrodes. The process consists of the acidification of the waste tire-derived pyrolytic char with mixed acids (HCl and HF) and the followed activation with KOH. The activated carbon exhibited a hierarchical meso-/micro-porous network with specific surface area 524 m2 g−1. A traditional three-electrode system was used to investigate the electrochemical performances of the activated carbon as a supercapacitor electrode material, which displayed a specific capacitance of ∼408 F g−1 at 0.25 A g−1 in an electrolyte of 6 M KOH, with capacitance retention of up to 97% after 10,000 charge/discharge cycles. This work offers an innovative and simple approach to yield higher performance activated carbon from waste tires for use in energy storage devices.