Fructose-Derived Hollow Carbon Nanospheres with Ultrathin and Ordered Mesoporous Shells as Cathodes in Lithium–Sulfur Batteries for Fast Energy Storage

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.