Construction of Porous Sulfur-Doped Petroleum Coke-Derived Carbon Materials with Adjustable Interlayer Spacing via a Low-Temperature Sulfurization Strategy and Its Efficient Sodium Storage Mechanism

To address the limitations of sodium-ion battery (SIB) anodes, porous sulfur-doped carbon materials derived from petroleum coke (PC) were synthesized through a green, scalable approach involving low-temperature sulfidation and gradient carbonization. This approach enabled the simultaneous expansion of the interlayer spacing (d002 = 0.373 nm for S-CY-850), and the construction of hierarchical pores (1–6 nm), achieved through thiophenic sulfur-induced lattice strain and in situ etching by CS2/SO2 evolution. The optimized S-CY-850 anode exhibited exceptional performance, including a high reversible capacity (420 mAh g–1 at 0.5 A g–1, representing a 5.38-fold improvement over undoped carbon), outstanding cycling stability (90.0% capacity retention after 2000 cycles), excellent rate capability (236.41 mAh g–1 at 5.0 A g–1), and an initial Coulombic efficiency (ICE) of 75.6%. This work presents a high-performance, low-cost anode solution for sodium-ion batteries (SIBs) derived from industrial byproducts, highlighting the synergistic effect of sulfur doping and microstructure modulation.