Nitrogen/oxygen/sulfur tri-doped hard carbon nanospheres derived from waste tires with high sodium and potassium anodic performances

Hard carbons (HCs) are more conductive to the intercalation and adsorption of Na and K ions than commercial graphite, enabling their application in sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). However, further improving the rate performance and cycle life of SIBs and PIBs has always been hindered. In this work, N, O, and S triple-doped hard carbons (NOS-HCs) with hierarchical micro/mesoporous structures were prepared by a one-step synthesis process. The adsorption effect of N and O in HCs could be weakened synergistically by the doping of S. Thus, the migration rate of solvated molecules is improved on the electrode surface. Furthermore, the reasonable adsorption effect caused by heteroatoms promotes sodium and potassium storage by adsorption and intercalation at defect edges. Based on the co-regulation between the turbine layers, porous structure, and defects of NOS-HC900, excellent rate capability (315.1 mA g(-1) at 2000 mA g(-1)) for SIBs and stable cycle performance (322.7 mA h g(-1) at 100 mA g(-1) after 1000 cycles) for PIBs were obtained. This work provides a simple and feasible strategy for improving the rate performance and cycle life of SIB and PIB anodes.