Fructose-derived hollow carbon nanospheres with ultrathin and ordered mesoporous shells as cathodes in lithium-sulfur batteries for fast energy storage

Abstract

Hollow carbon nanospheres with diameters of ≈300 nm and ultrathin, ordered mesoporous shells (OP‐HCS) are synthesized via the facile dual‐template‐assisted hydrothermal carbonization of eco‐friendly, sustainable, and inexpensive fructose, in which ordered concave nanopore arrays with an average distance of 10–12 nm and a pore diameter of 4.37 nm are integrated into the balloon‐like OP‐HCS particles. Lithium–sulfur batteries with S/OP‐HCS cathodes exhibit high sulfur utilization, excellent rate capabilities, and decent cycling stabilities. The S/OP‐HCS cathode with 71 wt% sulfur demonstrates an excellent discharge capacity of 483 mAh g−1 at the ultrahigh current of 5 C with an overpotential of ≈0.1 V. The cathode also presents an outstanding reversible capacity of 585 mAh g−1 at 2 C over 200 cycles and a prolonged and stable 600‐cycle performance with an average Coulombic efficiency of 97.0% cycle−1 at 1 C. The unique hierarchically ordered porous structure of the OP‐HCS conductive framework provides highly efficient Li+ diffusion and electron transfer, as well as excellent sulfur confinement. Overall, the fundamental understanding of the structural advantages of ordered porous OP‐HCS is expected to inspire the development of new functional carbon nanomaterials for other applications.